- Associate Professor, Pathology - (Research Scholar Track)
- Associate Professor, Applied BioSciences - GIDP
- Associate Professor, BIO5 Institute
- Ph.D. Cell & Molecular Biology
- Karl Ruprecht University of Heidelberg, Germany, Heidelberg, Germany
- Characterization of desmosomal glycoproteins
- University of Arizona, Tucson, Arizona (2015 - Ongoing)
- BIO5 Institute, University of Arizona (2009 - Ongoing)
- University of Arizona, Tucson, Arizona (2000 - 2015)
- University of Arizona, Tucson, Arizona (1998 - 2000)
- Martin Luther University (1995 - 1998)
- German Cancer Research Center (1994 - 1995)
- University of Arizona, Tucson, Arizona (1993 - 1994)
- European Molecular Biology Laboratory (EMBL) (1991 - 1993)
- German Cancer Research Center (1989 - 1991)
- Karl-Ruprecht University, College of Medicine, Anatomy (1982 - 1985)
- Israelian-German Scientific Program Committee of the Israelian-German Cooperation ProgramHeidelberg/Jerusalem, Fall 1997
- Presidential Prize
- International Society of Lymphology, Sao Paolo, Brazil, Fall 1995 (Award Nominee)
- Post-doctoral fellowship
- DFG/German Research Foundation, Spring 1991
- Cited as one of most downloaded articles
- Clinical Microbiology Newsletter/ Elsevier Inc., Spring 2017
My salary is a 100% supported by extramural funds. Therefore teaching is not a departmental requirement for me. However, I strongly believe in teaching and mentoring, and I always found contacts with students satisfactory and I welcomed students in my laboratory. I also trained and mentored colleagues, clinical as well as research staff. Students should derive long-term benefits from their time with me by continuing to grow and develop as scientists. My primary goal is to have a positive effect on the students' future professional practice. Part of the impact involves stimulating students to consider situations from perspectives different from those they normally adopt. This goal also involves encouraging students to develop career-long habits of self-motivated learning. In my opinion, to teach students how to think independently and “out of the box” is the most important aspect of teaching in general. A difficult teaching issue, but an important aspect of research, is the ambiguous, uncertain, and sometimes contradictory nature of research. Rather than supply students with static facts, I believe that I will serve them better by teaching them how to define a problem, how to decide what they need to solve it, how to find and evaluate new information, how to recognize their limits, and how to be prepared for change.
My primary research interest is to study how tumor cells escape immunosurveillance, which is a hallmark of cancer, in aggressive diffuse large B cell lymphoma (DLBCL) and other lymphomas. Major histocompatibility complex class II (MHCII) molecules are cell surface glycoproteins, which play a major role in tumor immunosurveillance. MHCII proteins are involved in antigen processing and presentation, and are important for the adaptive immune response. The expression of MHCII is essential for patient outcome. The loss of MHCII expression leads to a worse outcome for patients diagnosed with DLBCL. The lab is studying the underlying mechanisms of MHCII deregulation.I also have a strong interest in biorepository science. I am the PI of the ALTBR (Arizona Lymphoid Tissue and Blood Repository), which is an integral part of University of Arizona Cancer Center’s TACMASR core. The lab also hosts the Biorepository (ANCHOR-Arizona Biorepository) for a “Anal Cancer/HSIL Outcomes Research" (ANCHOR) study, which is sponsored by the National Cancer Institute’s Office of HIV and AIDS Malignancy (OHAM). It is a Phase III multi-site clinical trial. During the course of the 8-year clinical trial, the Biorepository will receive ~320,000 specimens for future NCI-approved correlative studies.
Directed ResearchNSCS 392 (Summer I 2018)
Directed ResearchECOL 492 (Spring 2017)
Directed ResearchECOL 492 (Fall 2016)
Honors Independent StudyMCB 399H (Spring 2016)
- Schmelz, M. (2006). Cytokeratin 6 expression in prostate stem cells. In Cancer Metastasis- Biology and Treatment: Adhesion and Cytoskeletal Molecules in Metastasis(pp 103-122). The Netherlands: Springer Science & Business Media, Dordrecht.
- Schmelz, M. (1990). Subplasmalemmal plaques intercellular junctions: common and distinguishing proteins. In Morphoregulatory Molecules(pp 285-314). New York: John Wiley & Sons.
- Schmelz, M. (1987). The desmosomal plaque and the cytoskeleton. In Junctional Complexes of Epithelial Cells(pp 26-44). Chichester: Wiley & Sons Ltd.
- Schmelz, M. (1983). Functional and anatomic aspects of central nervous cardiovascular regulation. In Central Cardiovascular Control(pp 1-30). Springer Verlag.
- Schmelz, M., Puvvada, S., Persky, D., Rivera, X., Heard, K., Guillrn-Rodriguez, J., & Schatz, J. (2017). A phase II Exploratory Study of PXD-101 (Belinostat) followed by zevalin in patients with relapsed aggressive high-risk lymphoma. Oncology, epub ahead of print. doi:10.1159/000479230More infoThis was a study in collaboration with Drs. Puvvada and Persky at the Arizona Cancer Center: Aggressive lymphomas (aNHL) including diffuse large B-cell lymphoma (DLBCL) have poor outcomes in relapsed refractory patients. Prior studies have demonstrated that loss of major histocompatibility complex class II (MHCII) expression in DLBCL is associated with poor survival. The objective of this single-arm phase II study was to evaluate if PXD-101 would increase MHCII expression, synergize with Zevalin, and improve clinical outcomes.The pleotropic effects of histone deacetylase inhibition and lack of clinical biomarkers have precluded a priori identification of responding patients. Thus, while we reported a negative trial of PXD-101 in combination with Zevalin, this study highlighted the importance of a clinically feasible biomarker.
- Zeng, Y., Hahn, S., Stokes, J., Hoffman, E., Schmelz, M., Poytcheva, M., Chernoff, J., & Emmanuel, K. (2017). Pak2 Regulates Myeloid Derived Suppressor Cell Development in Mice. Blood Advances, 1(22), 1923-1933. doi:10.1182/bloodadvances.2017007435More infoDr. Zeng and Dr. Schmelz collaborate via the Lymphoma Research Consortium. Dr. Schmelz provided expertise in histology, morphology and imaging to this project. This study showed that Pak2-KO CD11b highGr1high cells suppressed T-cell proliferation, consistent with an myeloid derived suppressor cell (MDSC) phenotype, and it shows a previously unrecognized role of Paks 2 in regulating MDSC development via both cell intrinsic and extrinsic mechanisms. The goal of the Lymphoma Research Consortium is to apply for a NIH/NCI program grant or a SPORE grant. A major step towards achieving this goal is for the members to build a record of published collaborative papers.
- Havas, A. P., Rodrigues, K. B., Bhakta, A., Demirjian, J. A., Hahn, S., Tran, J., Scavello, M., Tula-Sanchez, A. A., Zeng, Y., Schmelz, M., & Smith, C. L. (2016). Belinostat and vincristine demonstrate mutually synergistic cytotoxicity associated with mitotic arrest and inhibition of polyploidy in a preclinical model of aggressive diffuse large B cell lymphoma. Cancer Biology & Therapy, 17(12), 1240-1252.More infoDiffuse Large B-cell lymphoma (DLBCL) is an aggressive malignancy that has a 60 percent 5-year survival rate, highlighting a need for new therapeutic approaches. Histone deacetylase inhibitors (HDACi) are novel therapeutics being clinically-evaluated in combination with a variety of other drugs. However, rational selection of companion therapeutics for HDACi is difficult due to their poorly-understood, cell-type specific mechanisms of action. To address this, we developed a pre-clinical model system of sensitivity and resistance to the HDACi belinostat using DLBCL cell lines. In the current study, we demonstrate that cell lines sensitive to the cytotoxic effects of HDACi undergo early mitotic arrest prior to apoptosis. In contrast, HDACi-resistant cell lines complete mitosis after a short delay and arrest in G1. To force mitotic arrest in HDACi-resistant cell lines, we used low dose vincristine or paclitaxel in combination with belinostat and observed synergistic cytotoxicity. Belinostat curtails vincristine-induced mitotic arrest and triggers a strong apoptotic response associated with downregulated MCL-1 expression and upregulated BIM expression. Resistance to microtubule targeting agents (MTAs) has been associated with their propensity to induce polyploidy and thereby increase the probability of genomic instability that enables cancer progression. Co-treatment with belinostat effectively eliminated a vincristine-induced, actively cycling polyploid cell population. Our study demonstrates that vincristine sensitizes DLBCL cells to the cytotoxic effects of belinostat and that belinostat prevents polyploidy that could cause vincristine resistance. Our findings provide a rationale for using low dose MTAs in conjunction with HDACi as a potential therapeutic strategy for treatment of aggressive DLBCL.
- Schmelz, M. (2015). Langerhans Cell Histiocytosis (LCH) is Characterized by Distinct Cytoplasmic Expression of the Major Histocompatibility Class II Antigen (MHCII).. J. Hematopathology.More infoObjectives: Langerhans cell histiocytosis (LCH) is a monoclonal proliferation of antigen presenting cells (APC). In benign APCs, antigen loading occurs in the Major Histocompatibility class II (MHCII)-lysosomal compartment of the endocytic pathway followed by transport to the cell surface upon antigen stimulation. The pattern of MHC II expression in LCH is previously unreported.Methods: Subcellular MHCII localization was determined using immunohistochemisty (IHC) for the representative molecule HLA-DR. Pattern (cell surface, cytoplasmic granular, or cytoplasmic globular) and intensity (0 to 3+) were recorded for normal tissues and 44 LCH samples along with clinicopathologic features. The ultrastructural morphology of LCH was examined using transmission electronic microscopy (TEM).Results: HLA-DR cell surface expression was present on APCs, benign B cells, some T cells, and pulmonary macrophages. A granular cytoplasmic staining pattern (without surface expression) was seen in benign Langerhans cells (LCs) in the skin and histiocytes. Strikingly, all 44 LCH samples demonstrated both cytoplasmic granular and an unusual “globular” staining pattern with no surface staining. TEM of LCH revealed pronounced dilatation of the rough endoplasmic reticulum (RER) corresponding to the perinuclear globular MHCII aggregates observed by IHC. Conclusion: This is the first report of a highly specific HLA-DR staining pattern in LCH. The cytoplasmic perinuclear globular localization of MHCII in conjunction with the observation of extremely dilated RER suggests RER stress resulting in trapping MHCII due to lack of proper protein folding leading to a defect in antigen trafficking and/or arrest of LCH in an immature state with implications for diagnosis and pathogenesis.
- Schmelz, M. (2016). A phase II study of belinostat (PXD101) in relapsed and refractory aggressive B-cell lymphomas: SWOG S0520. Leukemia & Lymphoma, [Epub ahead of print], 1-11.More infoRecent advances in diffuse large B-cell lymphomas (DLBCL) have underscored the importance of tumor microenvironment in escaping host anti-tumor responses. One mechanism is loss of major histocompatibility Class II antigens (MHCII) associated with decreased tumor infiltrating T lymphocytes (TIL) and poor survival. Transcription of MHCII is controlled by CIITA which in turnis regulated by histone acetylation. In this study, we hypothesized that HDAC inhibition with belinostat increases MHCII, CIITA expression, TIL and improves patient outcomes. Primary objective was evaluation of toxicity and response. Twenty-two patients were enrolled for the study. Belinostat was well tolerated with mild toxicity. Two partial responses were observed at 5, 13 months after registration for an overall response rate (ORR) (95% CI) of 10.5% (1.3–33.1%), and three patients had stable disease for 4.7, 42.3+, and 68.4 + months with minimum 3-year follow-up. Included correlative studies support the hypothesis and serve as the basis for SWOG S0806 combining vorinostat with R-CHOP.
- Schmelz, M. (2016). Aberrant, cytoplasmic expression of MHC Class II confers a worse progression free survival in diffuse large B-cell lymphoma.. Virchows Archiv.More infoBackground: The loss of major histocompatibility class II (MHCII) mRNA and protein expression in diffuse large B-cell lymphoma (DLBCL) is associated with a decrease in tumor immunosurveillance and poor patient outcome. We previously demonstrated that well-recognized mechanisms for silencing such as, large genetic deletion, mutation, or methylation did not account for the MHCII deficiency. More recently, however, we inversely correlated MHCII expression and plasma cell markers. This suggests the absence of MHCII in some cases is related to blocked differentiation towards the plasma cell phenotype. We also observed an aberrant cytoplasmic staining in a subset of DLBCL that may also contribute to the loss of MHCII surface expression. The punctate or globular, cytoplasmic staining may indicate dysfunctional peptide processing and trafficking to the cell surface of MHCII proteins. Here, we correlate the presence of a punctate MHCII staining pattern with patient overall survival (OS) and progression free survival (PFS) to determine if DLBCL with potential aberrations in protein transport exhibit a similar clinical course to MHCII-negative cases. Methods: A total of 194 DLBCL formalin-fixed paraffin-embedded tissues (FFPET) with clinical annotation were constructed into a tissue microarray and stained with a pan-HLA antibody which detects all of the MHCII isoforms including HLA-DP, HLA-DQ, and HLA-DR. The immunohistochemical staining was performed at the BCCA on the Ventana BenchMark® XT instrument. The stained slides were independently scored for surface and cytoplasmic staining patterns in increments of 5% by two hematopathologists (R.D.G. and L.M.R). All patients received R-CHOP therapy. Overall and progression free survival (OS and PFS) were estimated with the Kaplan-Meier method using the date of lymphoma diagnosis. Significant differences were determined using the log-rank test and a P-value of less than 0.05. The use of human tissues and clinical data for this study was approved from the British Columbia Cancer Agency Institutional Review Board in accordance with the Declaration of Helsinki. Results: Within the 194 DLBCL FFPET, 59% (n=114) of cases contained at least 10% of cells with membrane HLA-DPQR expression. There were 22% (n=43) and 19% (n=37) of cases that were negative or consisted of the cytoplasmic staining pattern, respectively. Approximately 6% (n=12) of the cases displayed a mixture of cells with surface and cytoplasmic staining. Patients were stratified into MHCII membrane positive, cytoplasmic, and negative groups. The cytoplasmic staining pattern portended towards a worse OS (Figure 1A, P=0.095) with a significantly lower PFS (Figure 1B, P=0.006). When the cases with cytoplasmic staining were considered negative for MHCII, pooled with the negative cases, and compared to membrane positive the trend for a worse OS was no longer evident (Figure 1C, P=0.261). However, there was an almost 2-fold decrease in time to progression (8.5 vs. 4.5 y; Figure 1D, P=0.022). Conclusion: The MHCII punctate staining pattern within the cytoplasm of DLBCL cells identifies a possible failure in protein transport as a mechanism for the loss of surface expression. The correlation of the atypical MHCII expression with poor prognosis may indicate that this phenomenon also reduces the infiltration of T cells and subsequent immune escape similar to MHCII-negative DLBCL. Of interest, the altered MHCII membrane status and immune response may also affect progression of the disease as supported by the significant decrease in PFS of patients with cytoplasmic entrapment of MHCII proteins. Ongoing studies to further define the cytoplasmic localization of MHCII will provide clarity to the aberrant expression and may help to identify therapeutic targets to restore MHCII cell surface expression. Reactivating MHCII expression has the potential to enhance tumor immunosurveillance and patient outcome.
- Schmelz, M. (2016). Langerhans Cell Histiocytosis (LCH) is Characterized by Distinct Cytoplasmic Expression of the Major Histocompatibility Class II Antigen (MHCII).. J. Hematopathology.More infoObjectives: Langerhans cell histiocytosis (LCH) is a monoclonal proliferation of antigen presenting cells (APC). In benign APCs, antigen loading occurs in the Major Histocompatibility class II (MHCII)-lysosomal compartment of the endocytic pathway followed by transport to the cell surface upon antigen stimulation. The pattern of MHC II expression in LCH is previously unreported.Methods: Subcellular MHCII localization was determined using immunohistochemisty (IHC) for the representative molecule HLA-DR. Pattern (cell surface, cytoplasmic granular, or cytoplasmic globular) and intensity (0 to 3+) were recorded for normal tissues and 44 LCH samples along with clinicopathologic features. The ultrastructural morphology of LCH was examined using transmission electronic microscopy (TEM).Results: HLA-DR cell surface expression was present on APCs, benign B cells, some T cells, and pulmonary macrophages. A granular cytoplasmic staining pattern (without surface expression) was seen in benign Langerhans cells (LCs) in the skin and histiocytes. Strikingly, all 44 LCH samples demonstrated both cytoplasmic granular and an unusual “globular” staining pattern with no surface staining. TEM of LCH revealed pronounced dilatation of the rough endoplasmic reticulum (RER) corresponding to the perinuclear globular MHCII aggregates observed by IHC. Conclusion: This is the first report of a highly specific HLA-DR staining pattern in LCH. The cytoplasmic perinuclear globular localization of MHCII in conjunction with the observation of extremely dilated RER suggests RER stress resulting in trapping MHCII due to lack of proper protein folding leading to a defect in antigen trafficking and/or arrest of LCH in an immature state with implications for diagnosis and pathogenesis.
- Schmelz, M. (2017). Aberrant, cytoplasmic expression of MHC Class II confers a worse progression free survival in diffuse large B-cell lymphoma.. Virchows Archiv, 470, 113-117. doi:10.1007/s00428-016-2041-7More infoBackground: The loss of major histocompatibility class II (MHCII) mRNA and protein expression in diffuse large B-cell lymphoma (DLBCL) is associated with a decrease in tumor immunosurveillance and poor patient outcome. We previously demonstrated that well-recognized mechanisms for silencing such as, large genetic deletion, mutation, or methylation did not account for the MHCII deficiency. More recently, however, we inversely correlated MHCII expression and plasma cell markers. This suggests the absence of MHCII in some cases is related to blocked differentiation towards the plasma cell phenotype. We also observed an aberrant cytoplasmic staining in a subset of DLBCL that may also contribute to the loss of MHCII surface expression. The punctate or globular, cytoplasmic staining may indicate dysfunctional peptide processing and trafficking to the cell surface of MHCII proteins. Here, we correlate the presence of a punctate MHCII staining pattern with patient overall survival (OS) and progression free survival (PFS) to determine if DLBCL with potential aberrations in protein transport exhibit a similar clinical course to MHCII-negative cases. Methods: A total of 194 DLBCL formalin-fixed paraffin-embedded tissues (FFPET) with clinical annotation were constructed into a tissue microarray and stained with a pan-HLA antibody which detects all of the MHCII isoforms including HLA-DP, HLA-DQ, and HLA-DR. The immunohistochemical staining was performed at the BCCA on the Ventana BenchMark® XT instrument. The stained slides were independently scored for surface and cytoplasmic staining patterns in increments of 5% by two hematopathologists (R.D.G. and L.M.R). All patients received R-CHOP therapy. Overall and progression free survival (OS and PFS) were estimated with the Kaplan-Meier method using the date of lymphoma diagnosis. Significant differences were determined using the log-rank test and a P-value of less than 0.05. The use of human tissues and clinical data for this study was approved from the British Columbia Cancer Agency Institutional Review Board in accordance with the Declaration of Helsinki. Results: Within the 194 DLBCL FFPET, 59% (n=114) of cases contained at least 10% of cells with membrane HLA-DPQR expression. There were 22% (n=43) and 19% (n=37) of cases that were negative or consisted of the cytoplasmic staining pattern, respectively. Approximately 6% (n=12) of the cases displayed a mixture of cells with surface and cytoplasmic staining. Patients were stratified into MHCII membrane positive, cytoplasmic, and negative groups. The cytoplasmic staining pattern portended towards a worse OS (Figure 1A, P=0.095) with a significantly lower PFS (Figure 1B, P=0.006). When the cases with cytoplasmic staining were considered negative for MHCII, pooled with the negative cases, and compared to membrane positive the trend for a worse OS was no longer evident (Figure 1C, P=0.261). However, there was an almost 2-fold decrease in time to progression (8.5 vs. 4.5 y; Figure 1D, P=0.022). Conclusion: The MHCII punctate staining pattern within the cytoplasm of DLBCL cells identifies a possible failure in protein transport as a mechanism for the loss of surface expression. The correlation of the atypical MHCII expression with poor prognosis may indicate that this phenomenon also reduces the infiltration of T cells and subsequent immune escape similar to MHCII-negative DLBCL. Of interest, the altered MHCII membrane status and immune response may also affect progression of the disease as supported by the significant decrease in PFS of patients with cytoplasmic entrapment of MHCII proteins. Ongoing studies to further define the cytoplasmic localization of MHCII will provide clarity to the aberrant expression and may help to identify therapeutic targets to restore MHCII cell surface expression. Reactivating MHCII expression has the potential to enhance tumor immunosurveillance and patient outcome.
- Schmelz, M. (2016). Microtubule Poisons Sensitize DLBCL Cells to the Cytotoxic Effects of Histone Deacetylase Inhibitors. Leukemia & Lymphoma.
- Schmelz, M., Montes-Moreno, S., Piris, M., Wilkinson, S. T., & Rimsza, L. M. (2012). Lack and/or aberrant localization of major histocompatibility class II (MHCII) protein in plasmablastic lymphoma. Haematologica, 97(10), 1614-6.
- Jensen, V., Prasad, A. R., Smith, A., Raju, M., Wendel, C. S., Schmelz, M., Leyva, W., Warneke, J., & Krouse, R. S. (2010). Prognostic criteria for squamous cell cancer of the skin. The Journal of surgical research, 159(1), 509-16.More infoNon-well-differentiated cutaneous squamous cell carcinomas may display a more aggressive behavior. It is important to better define prognostic criteria for these tumors.
- Thai, H. M., Juneman, E., Lancaster, J., Hagerty, T., Do, R., Castellano, L., Kellar, R., Williams, S., Sethi, G., Schmelz, M., Gaballa, M., & Goldman, S. (2009). Implantation of a three-dimensional fibroblast matrix improves left ventricular function and blood flow after acute myocardial infarction. Cell transplantation, 18(3), 283-95.More infoThis study was designed to determine if a viable biodegradable three-dimensional fibroblast construct (3DFC) patch implanted on the left ventricle after myocardial infarction (MI) improves left ventricular (LV) function and blood flow. We ligated the left coronary artery of adult male Sprague-Dawley rats and implanted the 3DFC at the time of the infarct. Three weeks after MI, the 3DFC improved LV systolic function by increasing (p < 0.05) ejection fraction (37 +/- 3% to 62 +/- 5%), increasing regional systolic displacement of the infarcted wall (0.04 +/- 0.02 to 0.11 +/- 0.03 cm), and shifting the passive LV diastolic pressure volume relationship toward the pressure axis. The 3FDC improved LV remodeling by decreasing (p < 0.05) LV end-systolic and end-diastolic diameters with no change in LV systolic pressure. The 3DFC did not change LV end-diastolic pressure (LV EDP; 25 +/- 2 vs. 23 +/- 2 mmHg) but the addition of captopril (2mg/L drinking water) lowered (p < 0.05) LV EDP to 12.9 +/- 2.5 mmHg and shifted the pressure-volume relationship toward the pressure axis and decreased (p < 0.05) the LV operating end-diastolic volume from 0.49 +/- 0.02 to 0.34 +/- 0.03 ml. The 3DFC increased myocardial blood flow to the infarcted anterior wall after MI over threefold (p < 0.05). This biodegradable 3DFC patch improves LV function and myocardial blood flow 3 weeks after MI. This is a potentially new approach to cell-based therapy for heart failure after MI.
- Li, L., Schmelz, M., Kellner, E. M., Galgiani, J. N., & Orbach, M. J. (2007). Nuclear labeling of Coccidioides posadasii with green fluorescent protein. Annals of the New York Academy of Sciences, 1111, 198-207.More infoCoccidioidomycosis is a mild to life-threatening disease in otherwise healthy humans and other mammals caused by the fungus Coccidioides spp. Understanding the development of the unique dimorphic life cycle of Coccidioides spp. and its role in pathogenesis has been an area of research focus. However, nuclear behavior during the saprobic and parasitic life cycle has not been studied intensively. In this study, green fluorescent protein (GFP) was fused to histone H1 and introduced into Coccidioides posadasii (C. posadasii) strain Silveira to monitor the nuclear behavior of the fungus during the saprobic and parasitic stages of the life cycle. We constructed an Agrobacterium tumefaciens-mediated transformation (ATMT) vector that had in its T-DNA region a hygromycin-resistance gene as well as the fused histone H1-GFP gene under the control of the histone H3 promoter of C. posadasii. More than 30 hygromycin-resistant transformants were obtained and 23 were purified to homozygosity through multiple passages of the original transformants on hygromycin-containing media. One strain (VFC1420) transformed with a single copy of the fusion histone H1-GFP gene was selected for cytological studies. Strong nuclear-localized GFP signals were observed in arthroconidia, hyphae, as well as in spherules and endospores developed in vitro. Thus GFP can be used to study the expression pattern of potential virulence genes identified in serial analysis of gene expression (SAGE) or expressed sequence tags (EST) libraries, and could be a useful tool to monitor disease development in the murine model.
- Kremer, C. L., Schmelz, M., & Cress, A. E. (2006). Integrin-dependent amplification of the G2 arrest induced by ionizing radiation. The Prostate, 66(1), 88-96.More infoThe progressive loss of laminin 5 and the alpha6beta4 integrin is a characteristic of the transition of prostatic intraepithelial neoplasia (PIN) to invasive human prostate cancer. Our objective was to determine if the loss of the interaction with laminin 5 would influence the ability of human epithelial cells to respond to DNA damage. Three cellular damage responses to ionizing radiation (IR) were analyzed including G2 progression, cdc2 phosphorylation, and cell survival. The adhesion of normal human prostate epithelial cells to laminin 5 amplified the G2 arrest induced by IR, and depends on a known cell binding domain of laminin 5. The alteration of G2 arrest was confirmed by an inhibition of phospho-cdc2 nuclear translocation. In contrast, a prostate epithelial cancer cell line blocked in G2 independent of adhesion to laminin 5. The survival of these cell lines in response to IR was unaffected by adhesion to laminin 5. These results suggest that cell adhesion to laminin 5 in normal cells will amplify the IR induced G2 cell cycle progression block without altering cell survival. The loss of laminin 5 and the alpha6beta4 integrin in PIN lesions may contribute to the selection and progression of genetically unstable cell types via attenuation of a DNA damage induced G2 arrest.
- Li, L., Dial, S. M., Schmelz, M., Rennels, M. A., & Ampel, N. M. (2005). Cellular immune suppressor activity resides in lymphocyte cell clusters adjacent to granulomata in human coccidioidomycosis. Infection and immunity, 73(7), 3923-8.More infoThe in situ immunologic response in human coccidioidomycosis remains undefined. To explore this further, pulmonary necrotizing coccidioidal granulomata were examined using immunohistochemical staining for lymphocyte subsets and for the cytokines interleukin-10 (IL-10) and gamma interferon (IFN-gamma). Discrete perigranulomatous lymphocytic clusters were seen in eight of nine tissues examined. In these tissues, T lymphocytes (CD3+) significantly outnumbered B lymphocytes (CD20+) in the mantle area of the granulomata (P = 0.028), whereas the clusters were composed of roughly equal numbers of T and B lymphocytes. While the number of cells in the mantle expressing IL-10 was similar to those in the perigranulomatous clusters, there were significantly more cells expressing IFN-gamma in the mantle than in the clusters (P = 0.037). Confocal microscopy revealed that CD4+ T lymphocytes and B lymphocytes are associated with IL-10 production. CD4+CD25+ T lymphocytes were identified in the perigranulomatous clusters but were not associated with IL-10 production. This is the first report noting perigranulomatous lymphocyte clusters and IL-10 in association with human coccidioidal granulomata and suggests that down-regulation of the cellular immune response is occurring within coccidioidal granulomata.
- Schmelz, M., Moll, R., Hesse, U., Prasad, A. R., Gandolfi, J. A., Hasan, S. R., Bartholdi, M., & Cress, A. E. (2005). Identification of a stem cell candidate in the normal human prostate gland. European journal of cell biology, 84(2-3), 341-54.More infoStem cells of the human prostate gland have not yet been identified utilizing a structural biomarker. We have discovered a new prostatic epithelial cell phenotype-expressing cytokeratin 6a (Ck6a+ cells). The Ck6a+ cells are present within a specialized niche in the basal cell compartment in fetal, juvenile and adult prostate tissue, and within the stem cell-enriched urogenital sinus. In adult normal prostate tissue, the average abundance of Ck6a+ cells was 4.9%. With proliferative stimuli in the prostate organ culture model, in which the epithelial-stromal interaction was maintained, a remarkable increase of Ck6a expression was noticed to up to 64.9%. The difference in cytokeratin 6a expression between the normal adult prostate and the prostate organ culture model was statistically significant (p
- Wessells, H., King, S. H., Schmelz, M., Nagle, R. B., & Heimark, R. L. (2004). Immunohistochemical comparison of vascular and sinusoidal adherens junctions in cavernosal endothelium. Urology, 63(1), 201-6.More infoTo characterize endothelial cell-to-cell junctions in the sinusoids and microvasculature of the corpus cavernosum.
- Schmelz, M., Cress, A. E., Scott, K. M., Bürger, F., Cui, H., Sallam, K., McDaniel, K. M., Dalkin, B. L., & Nagle, R. B. (2002). Different phenotypes in human prostate cancer: alpha6 or alpha3 integrin in cell-extracellular adhesion sites. Neoplasia (New York, N.Y.), 4(3), 243-54.More infoThe distribution of alpha6/alpha3 integrin in adhesion complexes at the basal membrane in human normal and cancer prostate glands was analyzed in 135 biopsies from 61 patients. The levels of the polarized alpha6/alpha3 integrin expression at the basal membrane of prostate tumor glands were determined by quantitative immunohistochemistry. The alpha6/alpha3 integrin expression was compared with Gleason sum score, pathological stage, and preoperative serum prostate-specific antigen (PSA). The associations were assessed by statistical methods. Eighty percent of the tumors expressed the alpha6 or alpha3 integrin and 20% was integrin-negative. Gleason sum score, but not serum PSA, was associated with the integrin expression. Low Gleason sum score correlated with increased integrin expression, high Gleason sum score with low and negative integrin expression. Three prostate tumor phenotypes were distinguished based on differential integrin expression. Type I coexpressed both alpha6 and alpha3 subunits, type II exclusively expressed alpha6 integrin, and type III expressed alpha3 integrin only. Fifteen cases were further examined for the codistribution of vinculin, paxillin, and CD 151 on frozen serial sections using confocal laser scanning microscopy. The alpha6/alpha3 integrins, CD151, paxillin, and vinculin were present within normal glands. In prostate carcinoma, alpha6 integrin was colocalized with CD 151, but not with vinculin or paxillin. In tumor phenotype I, the alpha6 subunit did not colocalize with the alpha subunit indicating the existence of two different adhesion complexes. Human prostate tumors display on their cell surface the alpha6beta1 and/or alpha3beta1 integrins. Three tumor phenotypes associated with two different adhesion complexes were identified, suggesting a reorganization of cell adhesion structures in prostate cancer.
- Ayala, G. E., Wheeler, T. M., Shine, H. D., Schmelz, M., Frolov, A., Chakraborty, S., & Rowley, D. (2001). In vitro dorsal root ganglia and human prostate cell line interaction: redefining perineural invasion in prostate cancer. The Prostate, 49(3), 213-23.More infoLittle is understood regarding mechanisms of perineural invasion in prostate cancer progression. We present a novel model system and data that indicate perineural invasion is an active, specific, and reciprocal interaction between nerves and prostate cancer cells.
- Calaluce, R., Kunkel, M. W., Watts, G. S., Schmelz, M., Hao, J., Barrera, J., Gleason-Guzman, M., Isett, R., Fitchmun, M., Bowden, G. T., Cress, A. E., Futscher, B. W., & Nagle, R. B. (2001). Laminin-5-mediated gene expression in human prostate carcinoma cells. Molecular carcinogenesis, 30(2), 119-29.More infoInteractions between extracellular matrix (ECM) proteins and prostate carcinoma cells provide a dynamic model of prostate tumor progression. Previous work in our laboratory showed that laminin-5, an important member of a family of ECM glycoproteins expressed in the basal lamina, is lost in prostate carcinoma. Moreover, we showed that the receptor for laminin-5, the alpha6beta4 integrin, is altered in prostate tumors. However, the genes that laminin-5 potentially regulates and the significance of its loss of expression in prostate cancer are not known. We selected cDNA microarray as a comprehensive and systematic method for surveying and examining gene expression induced by laminin-5. To establish a definitive role for laminin-5 in prostate tumor progression and understand the significance of its loss of expression, we used a cDNA microarray containing 5289 human genes to detect perturbations of gene expression when DU145 prostate carcinoma cells interacted with purified laminin-5 after 0.5, 6, and 24 h. Triplicate experiments showed modulations of four, 61, and 14 genes at 0.5, 6, and 24 h, respectively. Genes associated with signal transduction, cell adhesion, the cell cycle, and cell structure were identified and validated by northern blot analysis. Protein expression was further assessed by immunohistochemistry. Mol. Carcinog. 30:119-129, 2001.
- Schmelz, M., Cress, A. E., Barrera, J., McDaniel, K. M., Davis, T. L., Fuchs, L., Dalkin, B. L., & Nagle, R. B. (2001). PEAZ-1: a new human prostate neoplastic epithelial cell line. The Prostate, 48(2), 79-92.More infoThe generation of prostatic cell lines provides in vitro models for experimental studies of the pathogenesis of prostate carcinoma. Therefore, we established and characterized a new human prostate epithelial cell line, PEAZ-1 (prostate epithelial Arizona-1).
- Schmelz, M., Schmid, V. J., & Parrish, A. R. (2001). Selective disruption of cadherin/catenin complexes by oxidative stress in precision-cut mouse liver slices. Toxicological sciences : an official journal of the Society of Toxicology, 61(2), 389-94.More infoPrevious work has shown that chemically induced oxidative stress disrupts the protein interactions of the E-cadherin/beta-catenin/alpha-catenin complex in precision-cut mouse liver slices (Parrish et al., 1999, Toxicol. Sci. 51, 80-86). Although these data suggest a role for oxidative stress in disruption of hepatic cadherin/catenin complexes, multiple complexes are co-expressed in the liver. Both E- and N- cadherin are co-expressed in hepatocytes, as well as beta-catenin and gamma-catenin; thus four distinct complexes mediate cell-cell adhesion in the liver: E-cadherin/beta-catenin/alpha-catenin, E-cadherin/gamma-catenin/alpha-catenin, N-cadherin/beta-catenin/alpha-catenin, and N-cadherin/gamma-catenin/alpha-catenin. Taking advantage of the retention of normal organ architecture and cellular heterogeneity offered by precision-cut mouse liver slices, the current study was designed to examine the impact of chemically induced oxidative stress on cadherin/catenin complexes. Precision-cut mouse liver slices were challenged with diamide (25-250 microM; 6 h) or tert-butylhydroperoxide (5-50 microM; 6 h). A polyclonal antibody against beta- or gamma-catenin was used to immunoprecipitate proteins prior to Western-blot analysis with monoclonal antibodies to E- or N-cadherin. Although a decrease in E-cadherin:beta-catenin co-immunoprecipitation was seen, interactions between beta-catenin and N-cadherin were not disrupted by chemical challenge. In addition, no effect on protein interactions of gamma-catenin with either cadherin was observed. Indirect immunofluorescence was used to co-localize catenins and cadherins following chemical challenge. Consistent with the biochemical observations, a heterogeneous reduction in co-localization of E-cadherin and beta-catenin was seen in precision-cut liver slices, but not other cadherin/catenin complexes. Taken together, these data suggest that oxidative stress selectively disrupts E-cadherin/beta-catenin complexes in the liver. This response is dictated, in part, by the protein composition of the cell-adhesion complex.
- Peitsch, W. K., Grund, C., Kuhn, C., Schnölzer, M., Spring, H., Schmelz, M., & Franke, W. W. (1999). Drebrin is a widespread actin-associating protein enriched at junctional plaques, defining a specific microfilament anchorage system in polar epithelial cells. European journal of cell biology, 78(11), 767-78.More infoUsing immunoblotting, immunprecipitation with subsequent fragment mass spectrometry, and immunolocalization techniques, we have detected the actin-binding ca. 120-kDa protein drebrin, originally identified in - and thought to be specific for - neuronal cells, in diverse kinds of human and bovine non-neuronal cells. Drebrin has been found in numerous cell culture lines and in many tissues of epithelial, endothelial, smooth muscle and neural origin but not in, for example, cardiac, skeletal and certain types of smooth muscle cells, in hepatocytes and in the human epithelium-derived cell culture line A-431. By double-label fluorescence microscopy we have found drebrin enriched in actin microfilament bundles associated with plaques of cell-cell contact sites representing adhering junctions. These drebrin-positive, adhering junction-associated bundles, however, are not identical with the vinculin-containing, junction-attached bundles, and in the same cell both subtypes of microfilament-anchoring plaques are readily distinguished by immunolocalization comparing drebrin and vinculin. The intracellular distribution of the drebrin- and the vinculin-based microfilament systems has been studied in detail by confocal fluorescence laser scanning microscopy in monolayers of the polar epithelial cell lines, MCF-7 and PLC, and drebrin has been found to be totally and selectively absent in the notoriously vinculin-rich focal adhesions. The occurrence and the possible functions of drebrin in non-neuronal cells, notably epithelial cells, and the significance of the existence of two different actin-anchoring junctional plaques is discussed.
- Schmelz, M., Way, D. L., Borgs, P., Peitsch, W. K., Schmidt, H., Witte, M. H., Witte, C. L., Franke, W. W., & Moll, R. (1998). A novel type of adhering junction in an epithelioid tumorigenic rat cell culture line. Cell and tissue research, 294(1), 11-25.More infoTwo major types of plaque-bearing adhering junctions are commonly distinguished: the actin microfilament-anchoring adhaerens junctions (AJs) and the desmosomes anchoring intermediate-sized filaments (IFs). Both types of junction usually possess the common plaque protein, plakoglobin, whereas the other plaque proteins and the transmembrane cadherins are mutually exclusive. For example, AJs contain E-, N-, or P-cadherin in combination with alpha- and beta-catenin, vinculin and alpha-actinin, whereas in desmosomes, desmogleins and desmocollins are associated with desmoplakin and one or several of the plakophilins (PP1-3). Here we describe a novel type of adhering junction comprising proteins of both AJs and desmosomes and the tight junction (TJ) plaque protein, ZO-1, in a newly established, liver-derived tumorigenic rat cell line (RMEC-1). By immunofluorescence microscopy, cell-cell contacts are characterized by mostly continuous-appearing lines which are usually resolved by electron microscopy as extended arrays of closely spaced small plaque subunits. These plaque-covered regions are positive for plakoglobin, alpha- and beta-catenin, the arm-repeat protein p120, vinculin, desmoplakin and protein ZO-1. They are positive for E-cadherin in cultures early on in passaging, but tend to turn negative for all known cadherins in densely grown cultures. On immunoblotting SDS-PAGE-separated proteins from dense-grown cell monolayers, "pan-cadherin" antibodies have reacted with a band at approximately 140 kDa, identified as N-cadherin by peptide fingerprinting of the immunoprecipitated protein, which for reasons not yet clear is modified or masked in immunolocalization experiments. The exact histological derivation of RMEC-1 cells is not known. However, the observations of several endothelial markers and the fact that all cells are rich in IFs containing vimentin and/or desmin, while only subpopulations also reveal IFs containing CKs 8 and 18, is suggestive of a mesenchymal, probably endothelial origin. We discuss the molecular relationship of this novel type of extended junction with other types of adhering junctions.
- Moll, I., Gillardon, F., Waltering, S., Schmelz, M., & Moll, R. (1996). Differences of bcl-2 protein expression between Merkel cells and Merkel cell carcinomas. Journal of cutaneous pathology, 23(2), 109-17.More infoThe bcl-2 gene, originally identified in B-cell lymphomas, encodes for proteins which may assume oncogenic functions by blocking apoptosis. Bcl-2 proteins are broadly distributed among various tissues, including epithelial ones. Within the skin, bcl-2 is strongly expressed in melanocytes, but its further distribution is yet unclear. The Merkel cells, neuroendocrine-epithelial cells of the skin, are present within the epidermis and hair follicles, mostly nerve-associated, and are believed to be postmitotic and long lived. Possibly they give rise to the malignant Merkel cell carcinomas. In the present study we investigated the bcl-2 expression on the protein level by means of immunohistochemical techniques including double confocal laser scanning microscopy, as well as on the RNA level by RT-PCR techniques, in Merkel cells, Merkel cell carcinomas, and cell lines. Merkel cells were identified by double staining for cytokeratins 20 or 8/18. We demonstrate that fetal epidermal and dermal Merkel cells are immunostained for bcl-2 protein, most of them clearly weaker than melanocytes. Adult Merkel cells also express bcl-2 protein very heterogeneously, mostly weak. In contrast, Merkel cell carcinomas are usually strongly positive for bcl-2 protein with some degree of heterogeneity. This is different from malignant melanomas in which bcl-2 expression is reduced as compared to normal melanocytes. Bcl-2 gene expression was also shown for Merkel cell carcinoma cell lines on both the mRNA and the protein level. Possibly bcl-2 protein expression is downregulated during the life span of Merkel cells, arguing that they may succumb to a certain cell turnover. The comparably high bcl-2 protein level in Merkel cell carcinomas may reflect peculiar biological and clinical characteristics.
- Moll, I., Zieger, W., & Schmelz, M. (1996). Proliferative Merkel cells were not detected in human skin. Archives of dermatological research, 288(4), 184-7.More infoThe fetal development of Merkel cells-neuroendocrine cells of the skin - has been a matter of debate for a long time. Recent results have helped to confirm their intraepidermal development in humans. Simple epithelial cytokeratins (CK) nos. 8, 18, 19 and 20 are well established markers at the light microscopic level. These cells could be detected from fetal week 8 within the epidermis with an enormous increase during the following weeks. This gives rise to the question as to whether Merkel cells are undergoing mitoses or whether they are derived from basal keratinocytes. We studied fetal and adult skin using antibodies to simple epithelial CK and to Ki67, a human nuclear cell proliferation-associated antigen in an attempt to answer these questions. In human adult and fetal skin of various stages we could not detect any Merkel cells undergoing cell division. These results suggest that Merkel cells are postmitotic cells to be renewed from undifferentiated keratinocytes with stem cell characteristics.
- Schmelz, M., Moll, R., Kuhn, C., & Franke, W. W. (1994). Complexus adhaerentes, a new group of desmoplakin-containing junctions in endothelial cells: II. Different types of lymphatic vessels. Differentiation; research in biological diversity, 57(2), 97-117.More infoIn diverse mammalian species, including (man, cow and rat) the very flat endothelial cells of lymphatic vessels of various organs, including the retothelial meshwork of sinus of lymph nodes, are connected by zonula-like plaque-bearing junctions which differ from the similarly structured junctions of blood vessel endothelia by the presence of desmoplakin or an as yet unknown but closely related plaque protein. These extended junctions, which also contain plakoglobin but none of the presently known desmogleins and desmocollins, are therefore different from the spot-like desmosomes (maculae adhaerentes) present in epithelia, myocardium and dendritic reticulum cells of lymphatic follicles, and are collectively subsumed under the new category of complexus adhaerentes, including the 'syndesmos' connecting the processes of the retothelial cells. The lymphatic endothelial cells possessing these special desmoplakin-containing junctions also contain the calcium-dependent transmembrane glycoproteins, V-cadherin and cadherin 5, of which the latter has also been partly localized to regions with desmoplakin-positive junctions. Possible functional reasons for the formation and maintenance of complexus adhaerentes are discussed as well as the potential value of reagents which allow their identification in relation to physiology and pathology.
- Schmelz, M., Sodeik, B., Ericsson, M., Wolffe, E. J., Shida, H., Hiller, G., & Griffiths, G. (1994). Assembly of vaccinia virus: the second wrapping cisterna is derived from the trans Golgi network. Journal of virology, 68(1), 130-47.More infoDuring the assembly of vaccinia virus, the intracellular mature virus becomes enwrapped by a cellular cisterna to form the intracellular enveloped virus (IEV), the precursor of the extracellular enveloped virus (EEV). In this study, we have characterized the origin of this wrapping cisterna by electron microscopic immunocytochemistry using lectins, antibodies against endocytic organelles, and recombinant vaccinia viruses expressing proteins which behave as Golgi resident proteins. No labelling for endocytic marker proteins could be detected on the wrapping membrane. However, the wrapping membrane labelled significantly for a trans Golgi network (TGN) marker protein. The recycling pathway from endosomes to the TGN appears to be greatly increased following vaccinia virus infection, since significant amounts of endocytic fluid-phase tracers were found in the lumen of the TGN, Golgi complex, and the wrapping cisternae. Using immunoelectron microscopy, we localized the vaccinia virus membrane proteins VV-p37, VV-p42, VV-p21, and VV-hemagglutinin (VV-HA) in large amounts in the wrapping cisternae, in the outer membranes of the IEV, and in the outermost membrane of the EEV. The bulk of the cellular VV-p37, VV-p21, and VV-p42 were in the TGN, whereas VV-HA was also found in large amounts on the plasma membrane and in endosomes. Collectively, these data argue that the TGN becomes enriched in vaccinia virus membrane proteins that facilitate the wrapping event responsible for the formation of the IEV.
- Schmelz, M., & Franke, W. W. (1993). Complexus adhaerentes, a new group of desmoplakin-containing junctions in endothelial cells: the syndesmos connecting retothelial cells of lymph nodes. European journal of cell biology, 61(2), 274-89.More infoWe describe, in bovine and human tissues, a new kind of adhering junctions ("complexus adhaerens") which occur in certain vascular endothelial and, by morphological and compositional criteria, are neither desmosomes nor adhering junctions of the zonula (fascia) adhaerens category. A particularly abundant and complex subtype among the "complexus adhaerens" junctions is characteristic of the endothelium-related, stellate cells that form the three-dimensional filter meshwork of lymph node sinus. These "retothelial" cells are multiply interconnected by junctions which are highly polymorphic in shape and size, often show interruptions and branches and can be traced for several micrometers. Their dense cytoplasmic plaque contains plakoglobin and desmoplakin but is practically negative for vinculin and alpha-actinin. In contrast to true desmosomes, including those of the dendritic reticulum cells of lymph node follicles, the retothelial junctions are negative for any of the known desmosomal cadherins (desmogleins and desmocollins) and also for E- and M-cadherin. These cells, however, are rich in cadherin-5 which colocalizes with desmoplakin and plakoglobin in numerous, though not all sites, indicating that here cadherin-5 may contribute to the formation of a desmoplakin plaque. The complex arrangement of the retothelial form of complexus adhaerens, for which the term "syndesmos" is proposed, has been reconstructed from electron micrographs by a computer-aided design. We also report that desmoplakin-positive complexus adhaerens junctions constitutively occur in various lymphatic endothelia of many other tissues, most prominently in submucosal lymph vessels, and discuss the possible function of this kind of junctions as a means to fortify cell connections between the tenuous endothelial cells and, in the lymph node sinus, to support their filtering functions.
- Koch, P. J., Goldschmidt, M. D., Walsh, M. J., Zimbelmann, R., Schmelz, M., & Franke, W. W. (1991). Amino acid sequence of bovine muzzle epithelial desmocollin derived from cloned cDNA: a novel subtype of desmosomal cadherins. Differentiation; research in biological diversity, 47(1), 29-36.More infoDesmosomes are cell-type-specific intercellular junctions found in epithelium, myocardium and certain other tissues. They consist of assemblies of molecules involved in the adhesion of specific cell types and in the anchorage of cell-type-specific cytoskeletal elements, the intermediate-size filaments, to the plasma membrane. To explore the individual desmosomal components and their functions we have isolated DNA clones encoding the desmosomal glycoprotein, desmocollin, using antibodies and a cDNA expression library from bovine muzzle epithelium. The cDNA-deduced amino-acid sequence of desmocollin (presently we cannot decide to which of the two desmocollins, DC I or DC II, this clone relates) defines a polypeptide with a calculated molecular weight of 85,000, with a single candidate sequence of 24 amino acids sufficiently long for a transmembrane arrangement, and an extracellular aminoterminal portion of 561 amino acid residues, compared to a cytoplasmic part of only 176 amino acids. Amino acid sequence comparisons have revealed that desmocollin is highly homologous to members of the cadherin family of cell adhesion molecules, including the previously sequenced desmoglein, another desmosome-specific cadherin. Using riboprobes derived from cDNAs for Northern-blot analyses, we have identified an mRNA of approximately 6 kb in stratified epithelia such as muzzle epithelium and tongue mucosa but not in two epithelial cell culture lines containing desmosomes and desmoplakins. The difference may indicate drastic differences in mRNA concentration or the existence of cell-type-specific desmocollin subforms. The molecular topology of desmocollin(s) is discussed in relation to possible functions of the individual molecular domains.
- Koch, P. J., Walsh, M. J., Schmelz, M., Goldschmidt, M. D., Zimbelmann, R., & Franke, W. W. (1990). Identification of desmoglein, a constitutive desmosomal glycoprotein, as a member of the cadherin family of cell adhesion molecules. European journal of cell biology, 53(1), 1-12.More infoMonoclonal antibodies to the constitutive desmosomal glycoprotein desmoglein were characterized whose epitopes are located intracellularly, i.e., in the cytoplasmic portion of this molecule, and contribute to the structure of the desmosomal plaque. Using one of these antibodies (DG3.10), a peptide was isolated from a proteolytic digest of desmoglein purified from isolated bovine muzzle demosomes, and its amino acid sequence was determined. In comparisons of this sequence with the amino acid sequence of desmoglein as deduced from the sequence of cDNA clones from the same tissue, encompassing most of approximately 7.6 kb mRNA and the complete coding region of 959 residues (calculated molecular weight approximately 102,400), the DG3.10 epitope was identified in a region starting 163 amino acids before the carboxy terminus in the first of four consecutive repeats of a homologous element of 29 +/- 1 amino acids. This topological information, together with the identification of a single hydrophobic region of sufficient length to provide a transmembrane segment and of several extended regions showing high sequence homology to various cadherins, has allowed the construction of a model of the molecular organization of desmoglein. We conclude that desmoglein is a member of the cadherin family of cell adhesion glycoproteins which is characterized by an unusually long cytoplasmic domain which exceeds those of the cadherins by more than 275 amino acids, contains special repetitive elements and spans the desmosomal plaque at least once.
- Schmelz, M., Duden, R., Cowin, P., & Franke, W. W. (1986). A constitutive transmembrane glycoprotein of Mr 165,000 (desmoglein) in epidermal and non-epidermal desmosomes. I. Biochemical identification of the polypeptide. European journal of cell biology, 42(2), 177-83.More infoTwo murine monoclonal antibodies (DG 3.4 and DG 3.10) raised against a major glycoprotein ("band 3 component") from desmosomes of bovine muzzle epidermis were used in immunoblot experiments following SDS-polyacrylamide gel electrophoresis or two-dimensional gel electrophoresis to identify this or immunologically related proteins in other bovine tissues and cultured cell lines. In all desmosome-bearing cells, i.e. cells also expressing desmoplakins, including representative of stratified, transitional and simple epithelia as well as myocardium, only a single distinct polypeptide of identical Mr value (165,000) and electrical charge was detected. These findings, together with the immunolocalization results reported in the companion paper indicate that this glycoprotein (desmoglein) is a general constituent protein of desmosomes, providing a case of an integral membrane protein co-expressed with non-membranous desmosomal proteins such as the plaque component, desmoplakin I. Our results further suggest that, contrary to previous suggestions, desmoglein is very similar, if not identical in different cells of the same species and does not display significant cell type diversity.
- Schmelz, M., Duden, R., Cowin, P., & Franke, W. W. (1986). A constitutive transmembrane glycoprotein of Mr 165,000 (desmoglein) in epidermal and non-epidermal desmosomes. II. Immunolocalization and microinjection studies. European journal of cell biology, 42(2), 184-99.More infoUsing two monoclonal antibodies described in the preceding paper we determined by immunofluorescence microscopy the distribution of an integral membrane protein of the desmosomal domain, the major glycopolypeptide of Mr 165,000 (bovine muzzle epidermal desmosome band 3; desmoglein) in various normal tissues, tumors and cultured cell lines from several mammalian species. This protein was detected in dotted or streak-like arrays along cell boundary structures which were known to contain non-membrane-integrated desmosomal plaque proteins such as desmoplakins. This is true for epithelial, i.e. cytokeratin-expressing cell types, for the desmin-producing myocardiac and Purkinje fiber cells of the heart, and for certain vimentin-containing cells such as arachnoidal and meningiomal cells and dendritic follicular cells of lymph nodes. However, on the basis of both immunoblot and immunocytochemical reactions, the protein is absent from non-desmosomal adhering junctions, including those devoid of desmoplakin but containing another plaque protein, plakoglobin ("band 5 protein"). We have used these antibodies to localize their epitopes with respect to the cell membrane. By immunoelectron microscopy we found that both epitopes are located in the desmosomal plaques, and this was confirmed by microinjection of purified antibodies into living cultured cells which resulted in labelling of the plaques. From these findings, taken together with previous analyses and localizations of the carbohydrate moieties of this glycoprotein, we conclude that desmoglein is a transmembrane glycoprotein which projects into--and contributes to--the desmosomal plaque structure. This glycoprotein represents a general component of true desmosomes and it is coexpressed with obligatory desmosome-specific plaque proteins such as desmoplakin I. The potential value of this glycoprotein as a desmosomal and cell type marker in histology and tumor diagnosis is discussed.
- Schmelz, M. (2017. Come in Out of the Cold: Alternatives to Freezing for Microbial Biorepositories(pp 27-34). Clinical Microbiology Newsletter, Vol 39, No 4.More infoThis review summarized the pros and cons of conservative and alternative novel specimen storage devices in biorepository science.The article appeared in January 2017. In April it was cited as one of most downloaded publications:https://www.journals.elsevier.com/clinical-microbiology-newletter/most-downloaded-articles
Other Teaching Materials
- Schmelz, M. (2017. Created 2 x Training Videos for Shipping Biospecimens. NIH/NCI-AMC ANCHOR.More infoWe created 2x Training videos, one for preparing shipments of refrigerated biospecimens, and one for preparing shipments of frozen specimens following IATA regulations for shipping biohazards. The training videos were posted on the ANCHOR Clinical Trial website. The staff of each newly activated clinical site has to watch the videos followed by a quiz prior to going "live".