Zhiyu Dai
- Assistant Professor, Internal Medicine
- Assistant Professor, Clinical Translational Sciences
- Assistant Professor, BIO5 Institute
- Member of the Graduate Faculty
Contact
- (602) 827-2982
- Biosciences Partnership Phx, Rm. 9TH FL
- Phoenix, AZ 85004
- zhiyudai@arizona.edu
Degrees
- Ph.D.
- Sun Yat-sen University, Guangzhou, China
Awards
- Early Career Excellence in Research Award, University of Arizona College of Medicine Phoenix
- University of Arizona College of Medicine Phoenix, Winter 2023
- Chinese-American Lung Association Service Award
- Chinese-American Lung Association, Spring 2023
- The Cournand and Comroe Early Career Investigator Prize
- American Heart Association, Winter 2022 (Award Finalist)
- Chinese-American Lung Association Early Career Investigator Award
- Chinese-American Lung Association, Summer 2022
- Fellow of the American Heart Association (FAHA)
- American Heart Association, Summer 2022
- Pew Biomedical Scholars
- Pew Foundation, Summer 2022 (Award Nominee)
- George H. Davis Fellowship
- University of Arizona, Winter 2021
- 2021 Mallinckrodt Grants
- Mallinckrodt Foundation, Spring 2021 (Award Nominee)
- Career Development Award
- American Heart Association, Summer 2020
- Grover Conference Young Investigator Award
- Grover Conference, Fall 2019
Interests
Research
Pulmonary vascular diseasesVascular biology
Courses
2023-24 Courses
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Research
CR 900 (Fall 2023)
2022-23 Courses
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Thesis
CTS 910 (Fall 2022)
Scholarly Contributions
Journals/Publications
- Dai, Z., & Thorp, E. B. (2023). New Way to Study Pulmonary Hypertension in HFpEF. Circulation research, 133(11), 899-901.
- James, J., Dekan, A., Niihori, M., McClain, N., Varghese, M., Bharti, D., Lawal, O. S., Padilla-Rodrigez, M., Yi, D., Dai, Z., Gusev, O., Rafikova, O., & Rafikov, R. (2023). Novel Populations of Lung Capillary Endothelial Cells and Their Functional Significance. Research square.More infoThe role of the lung's microcirculation and capillary endothelial cells in normal physiology and the pathobiology of pulmonary diseases is unequivocally vital. The recent discovery of molecularly distinct aerocytes and general capillary (gCaps) endothelial cells by single-cell transcriptomics (scRNAseq) advanced the field in understanding microcirculatory milieu and cellular communications. However, increasing evidence from different groups indicated the possibility of more heterogenic structures of lung capillaries. Therefore, we investigated enriched lung endothelial cells by scRNAseq and identified five novel populations of gCaps with distinct molecular signatures and roles. Our analysis suggests that two populations of gCaps that express Scn7a(Na) and Clic4(Cl) ion transporters form the arterial-to-vein zonation and establish the capillary barrier. We also discovered and named mitotically-active "root" cells (Flot1+) on the interface between arterial, Scn7a+, and Clic4 + endothelium, responsible for the regeneration and repair of the adjacent endothelial populations. Furthermore, the transition of gCaps to a vein requires a venous-capillary endothelium expressing Lingo2. Finally, gCaps detached from the zonation represent a high level of Fabp4, other metabolically active genes, and tip-cell markers showing angiogenesis-regulating capacity. The discovery of these populations will translate into a better understanding of the involvement of capillary phenotypes and their communications in lung disease pathogenesis.
- Lee, W. H., Ong, S., Shao, N., Dai, Z., Denaro III, P., Le, H. H., & Liu, C. (2023).
E-cigarettes induce dysregulation of autophagy leading to endothelial dysfunction in pulmonary arterial hypertension
. Stem Cells. - Pan, J., Liu, B., & Dai, Z. (2023). The Role of a Lung Vascular Endothelium Enriched Gene TMEM100. Biomedicines, 11(3).More infoTransmembrane protein 100 (TMEM100) is a crucial factor in the development and maintenance of the vascular system. The protein is involved in several processes such as angiogenesis, vascular morphogenesis, and integrity. Furthermore, TMEM100 is a downstream target of the BMP9/10 and BMPR2/ALK1 signaling pathways, which are key regulators of vascular development. Our recent studies have shown that TMEM100 is a lung endothelium enriched gene and plays a significant role in lung vascular repair and regeneration. The importance of TMEM100 in endothelial cells' regeneration was demonstrated when Tmem100 was specifically deleted in endothelial cells, causing an impairment in their regenerative ability. However, the role of TMEM100 in various conditions and diseases is still largely unknown, making it an interesting area of research. This review summarizes the current knowledge of TMEM100, including its expression pattern, function, molecular signaling, and clinical implications, which could be valuable in the development of novel therapies for the treatment of cardiovascular and pulmonary diseases.
- Qi, W., Fang, Z., Luo, C., Hong, H., Long, Y., Dai, Z., Liu, J., Zeng, Y., Zhou, T., Xia, Y., Yang, X., & Gao, G. (2023). The critical role of BTRC in hepatic steatosis as an ATGL E3 ligase. Journal of molecular cell biology.More infoNon-alcoholic fatty liver disease (NAFLD), characterized by hepatic steatosis, is one of the commonest causes for liver dysfunction. Adipose triglyceride lipase (ATGL) is closely related to lipid turnover and hepatic steatosis as the speed-limited triacylglycerol lipase in liver lipolysis. However, the expression and regulation of ATGL in NAFLD remain unclear. Herein, our results showed that ATGL protein levels were decreased in the liver tissues of high-fat diet (HFD)-fed mice, naturally obese mice, and cholangioma/hepatic carcinoma patients with hepatic steatosis, as well as in the oleic acid-induced hepatic steatosis cell model, while ATGL mRNA levels were not changed. ATGL protein was mainly degraded through the proteasome pathway in hepatocytes. beta-transducin repeat containing (BTRC) was upregulated and negatively correlated with the decreased ATGL level in these hepatic steatosis models. Consequently, BTRC was identified as the E3 ligase for ATGL through predominant ubiquitination at the lysine 135 residue. Moreover, adenovirus-mediated knockdown of BTRC ameliorated steatosis in HFD-fed mouse livers and oleic acid-treated liver cells via upregulating the ATGL level. Taken together, BTRC plays a crucial role in hepatic steatosis as a new ATGL E3 ligase and may serve as a potential therapeutic target for treating NAFLD.
- Yi, D., Liu, B., Ding, H., Li, S., Li, R., Pan, J., Ramirez, K., Xia, X., Kala, M., Ye, Q., Lee, W. H., Frye, R. E., Wang, T., Zhao, Y., Knox, K. S., Glembotski, C. C., Fallon, M. B., & Dai, Z. (2023). E2F1 Mediates SOX17 Deficiency-Induced Pulmonary Hypertension. Hypertension (Dallas, Tex. : 1979), 80(11), 2357-2371.More infoRare genetic variants and genetic variation at loci in an enhancer in SOX17 (SRY-box transcription factor 17) are identified in patients with idiopathic pulmonary arterial hypertension (PAH) and PAH with congenital heart disease. However, the exact role of genetic variants or mutations in SOX17 in PAH pathogenesis has not been reported.
- Dai, Z., Cheng, J., Liu, B., Yi, D., Feng, A., Wang, T., An, L., Gao, C., Wang, Y., Zhu, M. M., Zhang, X., & Zhao, Y. Y. (2021). Loss of Endothelial Hypoxia Inducible Factor-Prolyl Hydroxylase 2 Induces Cardiac Hypertrophy and Fibrosis. Journal of the American Heart Association, 10(22), e022077.More infoBackground Cardiac hypertrophy and fibrosis are common adaptive responses to injury and stress, eventually leading to heart failure. Hypoxia signaling is important to the (patho)physiological process of cardiac remodeling. However, the role of endothelial PHD2 (prolyl-4 hydroxylase 2)/hypoxia inducible factor (HIF) signaling in the pathogenesis of cardiac hypertrophy and heart failure remains elusive. Methods and Results Mice with (-Cre-mediated deletion of [encoding PHD2]) exhibited left ventricular hypertrophy evident by increased thickness of anterior and posterior wall and left ventricular mass, as well as cardiac fibrosis. Tamoxifen-induced endothelial deletion in adult mice also induced left ventricular hypertrophy and fibrosis. Additionally, we observed a marked decrease of PHD2 expression in heart tissues and cardiovascular endothelial cells from patients with cardiomyopathy. Moreover, genetic ablation of but not in mice normalized cardiac size and function. RNA sequencing analysis also demonstrated HIF-2α as a critical mediator of signaling related to cardiac hypertrophy and fibrosis. Pharmacological inhibition of HIF-2α attenuated cardiac hypertrophy and fibrosis in mice. Conclusions The present study defines for the first time an unexpected role of endothelial PHD2 deficiency in inducing cardiac hypertrophy and fibrosis in an HIF-2α-dependent manner. PHD2 was markedly decreased in cardiovascular endothelial cells in patients with cardiomyopathy. Thus, targeting PHD2/HIF-2α signaling may represent a novel therapeutic approach for the treatment of pathological cardiac hypertrophy and failure.
- Evans, C. E., Cober, N. D., Dai, Z., Stewart, D. J., & Zhao, Y. Y. (2021). Endothelial Cells in the Pathogenesis of Pulmonary Arterial Hypertension. The European respiratory journal.More infoPulmonary arterial hypertension (PAH) is a devastating disease that involves pulmonary vasoconstriction, small vessel obliteration, large vessel thickening and obstruction, and development of plexiform lesions. PAH vasculopathy leads to progressive increases in pulmonary vascular resistance, right heart failure, and ultimately, premature death. Besides other cell types that are known to be involved in PAH pathogenesis ( smooth muscle cells, fibroblasts, and leukocytes), recent studies demonstrate a crucial role of endothelial cells (ECs) in the initiation and progression of PAH. The EC-specific role in PAH is multi-faceted and impacts upon numerous pathophysiological processes including vasoconstriction, inflammation, coagulation, metabolism, and oxidative/nitrative stress, as well as cell viability, growth, and differentiation. In this review, we describe how EC dysfunction and cell signalling regulate the pathogenesis of PAH. We also highlight areas of research that warrant attention in future studies, and discuss potential molecular signalling pathways in ECs that could be targeted therapeutically in the prevention and treatment of PAH.
- Yi, D., Liu, B., Wang, T., Liao, Q., Zhu, M. M., Zhao, Y. Y., & Dai, Z. (2021). Endothelial Autocrine Signaling through CXCL12/CXCR4/FoxM1 Axis Contributes to Severe Pulmonary Arterial Hypertension. International journal of molecular sciences, 22(6).More infoEndothelial autocrine signaling is essential to maintain vascular homeostasis. There is limited information about the role of endothelial autocrine signaling in regulating severe pulmonary vascular remodeling during the onset of pulmonary arterial hypertension (PAH). In this study, we employed the first severe pulmonary hypertension (PH) mouse model, (-mediated disruption of ) mice, to identify the novel autocrine signaling mediating the pulmonary vascular endothelial cell (PVEC) proliferation and the pathogenesis of PAH. PVECs isolated from lung expressed upregulation of many growth factors or angiocrine factors such as CXCL12, and exhibited pro-proliferative phenotype coincident with the upregulation of proliferation-specific transcriptional factor FoxM1. Treatment of CXCL12 on PVECs increased FoxM1 expression, which was blocked by CXCL12 receptor CXCR4 antagonist AMD3100 in cultured human PVECs. The endothelial specific deletion of ) or AMD3100 treatment mice downregulated FoxM1 expression in vivo. We then generated and characterized a novel mouse model with endothelial specific FoxM1 deletion in mice (), and found that endothelial FoxM1 deletion reduced pulmonary vascular remodeling and right ventricular systolic pressure. Together, our study identified a novel mechanism of endothelial autocrine signaling in regulating PVEC proliferation and pulmonary vascular remodeling in PAH.
- Kelly, G. T., Faraj, R., Dai, Z., Cress, A. E., & Wang, T. (2020). A mutation found in esophageal cancer alters integrin β4 mRNA splicing. Biochemical and biophysical research communications, 529(3), 726-732.More infoIntegrin β4 (CD104, mRNA: ITGβ4) contributes to anchoring cells to the extracellular matrix and is regulated in many cancer types where it contributes to tumor progression. One splice variant, integrin β4E, is poorly characterized. We extracted several mutations from tumor samples within ITGB4 near the splice site that controls ITGβ4E production, and computational analysis predicted six of these would alter splicing to alter ITGβ4E abundance. One of these mutations, from an esophageal squamous cell carcinoma sample, was predicted to increase splicing toward ITGβ4E. We verified this effect using a minigene, and observed that integrin β4E slows esophageal squamous cell migration while other variants enhance migration, demonstrating that integrin β4E regulation through mutations may contribute to esophageal squamous cell tumorigenesis.
- Dai, Z., & Zhao, Y. Y. (2019). BET in Pulmonary Arterial Hypertension: Exploration of BET Inhibitors to Reverse Vascular Remodeling. American journal of respiratory and critical care medicine, 200(7), 806-808.
- Dai, Z., Zhu, M. M., Peng, Y., Jin, H., Machireddy, N., Qian, Z., Zhang, X., & Zhao, Y. Y. (2018). Endothelial and Smooth Muscle Cell Interaction via FoxM1 Signaling Mediates Vascular Remodeling and Pulmonary Hypertension. American journal of respiratory and critical care medicine, 198(6), 788-802.More infoAngioproliferative vasculopathy is a hallmark of pulmonary arterial hypertension (PAH). However, little is known about how endothelial cell (EC) and smooth muscle cell (SMC) crosstalk regulates the angioproliferative vascular remodeling.
- Dai, Z., Zhu, M. M., Peng, Y., Machireddy, N., Evans, C. E., Machado, R., Zhang, X., & Zhao, Y. Y. (2018). Therapeutic Targeting of Vascular Remodeling and Right Heart Failure in Pulmonary Arterial Hypertension with a HIF-2α Inhibitor. American journal of respiratory and critical care medicine, 198(11), 1423-1434.More infoPulmonary arterial hypertension (PAH) is a devastating disease characterized by progressive vasoconstriction and obliterative vascular remodeling that leads to right heart failure (RHF) and death. Current therapies do not target vascular remodeling and RHF, and result in only modest improvement of morbidity and mortality.
- Zhang, T., Yin, P., Zhang, Z., Xu, B., Di Che, ., Dai, Z., Dong, C., Jiang, P., Hong, H., Yang, Z., Zhou, T., Shao, J., Xu, Z., Yang, X., & Gao, G. (2018). Correction: Deficiency of pigment epithelium-derived factor in nasopharyngeal carcinoma cells triggers the epithelial-mesenchymal transition and metastasis. Cell death & disease, 9(8), 784.More infoThe PDF and HTML versions of the article have been updated to include the Creative Commons Attribution 4.0 International License information.Correction to: Cell Death Dis. 5, e1484 (2014); https://doi.org/10.1038/cddis.2014.408 ; published online 23 October 2014.
- Dai, Z. (2017). Invited commentary. Journal of vascular surgery, 65(4), 1170.
- Dai, Z., & Zhao, Y. Y. (2017). Discovery of a murine model of clinical PAH: Mission impossible?. Trends in cardiovascular medicine, 27(4), 229-236.More infoPulmonary arterial hypertension (PAH) is a lung vascular disease characterized with a progressive increase of pulmonary vascular resistance and obliterative pulmonary vascular remodeling resulting in right heart failure and premature death. In this brief review, we document the recent advances in identifying genetically modified murine models of PH, with a focus on the recent discovery of the mouse model of Tie2 Cre-mediated deletion of prolyl hydroxylase 2, which exhibits progressive obliterative vascular remodeling, severe PAH, and right heart failure, thus recapitulating many of the features of clinical PAH. We will also discuss the translational potential of recent findings arising from experimental studies of murine PH models.
- Fang, S., Hong, H., Li, L., He, D., Xu, Z., Zuo, S., Han, J., Wu, Q., Dai, Z., Cai, W., Ma, J., Shao, C., Gao, G., & Yang, X. (2017). Plasminogen kringle 5 suppresses gastric cancer via regulating HIF-1α and GRP78. Cell death & disease, 8(10), e3144.More infoInhibition of tumour angiogenesis has an important role in antitumour therapy. However, a recent study indicates that antiangiogenesis therapy may lead to glucose-related protein 78 (GRP78) associated antiapoptotic resistance. The present study aims to elucidate the dual effects of plasminogen kringle 5 (K5) on tumour angiogenesis and apoptosis induction by targeting hypoxia-inducible factor 1α (HIF-1α) and GRP78. Co-immunoprecipitation and western blotting were used for examining the ubiquitination of HIF-1α and analysing angiogenesis and apoptosis-associated proteins. K5 promoted the sumo/ubiquitin-mediated proteasomal degradation of HIF-1α by upregulating von Hippel-Lindau protein under hypoxia, resulting in the reduction of vascular endothelial growth factor and thus suppressing tumour angiogenesis. Furthermore, K5 decreased GRP78 expression via downregulation of phosphorylated extracellular-regulated protein kinase, leading to caspase-7 cleavage and tumour cell apoptosis. Blocking voltage-dependent anion channel abrogated the effects of K5 on both HIF-1α and GRP78. K5 significantly inhibited the growth of gastric carcinoma xenografts by inhibiting both angiogenesis and apoptosis. The dual effects suggest that K5 might be a promising bio-therapeutic agent in the treatment of gastric cancer, particularly in patients who exhibit the induction of GRP78.
- Wu, C., Evans, C. E., Dai, Z., Huang, X., Zhang, X., Jin, H., Hu, G., Song, Y., & Zhao, Y. Y. (2017). Lipopolysaccharide-induced endotoxemia in corn oil-preloaded mice causes an extended course of lung injury and repair and pulmonary fibrosis: A translational mouse model of acute respiratory distress syndrome. PloS one, 12(3), e0174327.More infoAcute respiratory distress syndrome (ARDS) is characterized by acute hypoxemia respiratory failure, bilateral pulmonary infiltrates, and pulmonary edema of non-cardiac origin. Effective treatments for ARDS patients may arise from experimental studies with translational mouse models of this disease that aim to delineate the mechanisms underlying the disease pathogenesis. Mouse models of ARDS, however, can be limited by their rapid progression from injured to recovery state, which is in contrast to the course of ARDS in humans. Furthermore, current mouse models of ARDS do not recapitulate certain prominent aspects of the pathogenesis of ARDS in humans. In this study, we developed an improved endotoxemic mouse model of ARDS resembling many features of clinical ARDS including extended courses of injury and recovery as well as development of fibrosis following i.p. injection of lipopolysaccharide (LPS) to corn oil-preloaded mice. Compared with mice receiving LPS alone, those receiving corn oil and LPS exhibited extended course of lung injury and repair that occurred over a period of >2 weeks instead of 3-5days. Importantly, LPS challenge of corn oil-preloaded mice resulted in pulmonary fibrosis during the repair phase as often seen in ARDS patients. In summary, this simple novel mouse model of ARDS could represent a valuable experimental tool to elucidate mechanisms that regulate lung injury and repair in ARDS patients.
- Zhang, T., Yin, P., Zhang, Z., Xu, B., Che, D., Dai, Z., Dong, C., Jiang, P., Hong, H., Yang, Z., Zhou, T., Shao, J., Xu, Z., Yang, X., & Gao, G. (2017). Deficiency of pigment epithelium-derived factor in nasopharyngeal carcinoma cells triggers the epithelial-mesenchymal transition and metastasis. Cell death & disease, 8(6), e2838.More infoDistant metastasis is the primary cause of nasopharyngeal carcinoma (NPC) treatment failure while epithelial-mesenchymal transition (EMT) is the critical process of NPC invasion and metastasis. However, tumor-suppressor genes involved in the EMT and metastasis of NPC have not been explored clearly compared with the oncogenes. In the present study, the expression of pigment epithelium-derived factor (PEDF), a potent endogenous antitumor factor, was diminished in human NPC tissues and associated with clinicopathological and EMT features. The knockdown of PEDF induced EMT in lower metastatic NPC cell lines and overexpression of PEDF restored epithelial phenotype in higher metastatic NPC cell lines with typical EMT. The inhibition of PEDF mediated NPC cell spontaneous metastasis in vivo. LRP6/GSK3β/β-catenin signal pathway rather than AKT/GSK3β pathway was involved in the effects of PEDF on EMT. The expression of PEDF was directly downregulated by elevated miR-320c in NPC. In conclusion, our findings indicate for the first time that PEDF functions as tumor-suppressor gene in the occurrence of EMT and metastasis in NPC. PEDF could serve as a promising candidate for NPC diagnosis, prognosis and treatment.
- Dai, Z., Li, M., Wharton, J., Zhu, M. M., & Zhao, Y. Y. (2016). Prolyl-4 Hydroxylase 2 (PHD2) Deficiency in Endothelial Cells and Hematopoietic Cells Induces Obliterative Vascular Remodeling and Severe Pulmonary Arterial Hypertension in Mice and Humans Through Hypoxia-Inducible Factor-2α. Circulation, 133(24), 2447-58.More infoVascular occlusion and complex plexiform lesions are hallmarks of the pathology of severe pulmonary arterial hypertension (PAH) in patients. However, the mechanisms of obliterative vascular remodeling remain elusive; hence, current therapies have not targeted the fundamental disease-modifying mechanisms and result in only modest improvement in morbidity and mortality.
- Qi, W., Yang, C., Dai, Z., Che, D., Feng, J., Mao, Y., Cheng, R., Wang, Z., He, X., Zhou, T., Gu, X., Yan, L., Yang, X., Ma, J. X., & Gao, G. (2015). High levels of pigment epithelium-derived factor in diabetes impair wound healing through suppression of Wnt signaling. Diabetes, 64(4), 1407-19.More infoDiabetic foot ulcer (DFU) caused by impaired wound healing is a common vascular complication of diabetes. The current study revealed that plasma levels of pigment epithelium-derived factor (PEDF) were elevated in type 2 diabetic patients with DFU and in db/db mice. To test whether elevated PEDF levels contribute to skin wound-healing delay in diabetes, endogenous PEDF was neutralized with an anti-PEDF antibody in db/db mice. Our results showed that neutralization of PEDF accelerated wound healing, increased angiogenesis in the wound skin, and improved the functions and numbers of endothelial progenitor cells (EPCs) in the diabetic mice. Further, PEDF-deficient mice showed higher baseline blood flow in the skin, higher density of cutaneous microvessels, increased skin thickness, improved numbers and functions of circulating EPCs, and accelerated wound healing compared with wild-type mice. Overexpression of PEDF suppressed the Wnt signaling pathway in the wound skin. Lithium chloride-induced Wnt signaling activation downstream of the PEDF interaction site attenuated the inhibitory effect of PEDF on EPCs and rescued the wound-healing deficiency in diabetic mice. Taken together, these results suggest that elevated circulating PEDF levels contribute to impaired wound healing in the process of angiogenesis and vasculogenesis through the inhibition of Wnt/β-catenin signaling.
- Cai, L., Yi, F., Dai, Z., Huang, X., Zhao, Y. D., Mirza, M. K., Xu, J., Vogel, S. M., & Zhao, Y. Y. (2014). Loss of caveolin-1 and adiponectin induces severe inflammatory lung injury following LPS challenge through excessive oxidative/nitrative stress. American journal of physiology. Lung cellular and molecular physiology, 306(6), L566-73.More infoExcessive reactive oxygen/nitrogen species have been associated with the onset, progression, and outcome of sepsis, both in preclinical and clinical studies. However, the signaling pathways regulating oxidative/nitrative stress in the pathogenesis of sepsis-induced acute lung injury and acute respiratory distress syndrome are not fully understood. Employing the novel mouse model with genetic deletions of both caveolin-1 (Cav1) and adiponectin (ADPN) [double knockout (DKO) mice], we have demonstrated the critical role of Cav1 and ADPN signaling cross talk in regulating oxidative/nitrative stress and resulting inflammatory lung injury following LPS challenge. In contrast to the inhibited inflammatory lung injury in Cav1(-/-) mice, we observed severe lung inflammation and markedly increased lung vascular permeability in DKO mice in response to LPS challenge. Accordingly, the DKO mice exhibited an 80% mortality rate following a sublethal dose of LPS challenge. At basal state, loss of Cav1 and ADPN resulted in a drastic increase of oxidative stress and resultant nitrative stress in DKO lungs. Scavenging of superoxide by pretreating the DKO mice with MnTMPYP (a superoxide dismutase mimetic) restored the inflammatory responses to LPS challenge including reduced lung myeloperoxidase activity and vascular permeability. Thus oxidative/nitrative stress collectively modulated by Cav1 and ADPN signalings is a critical determinant of inflammatory lung injury in response to LPS challenge.
- Hong, H., Zhou, T., Fang, S., Jia, M., Xu, Z., Dai, Z., Li, C., Li, S., Li, L., Zhang, T., Qi, W., Bardeesi, A. S., Yang, Z., Cai, W., Yang, X., & Gao, G. (2014). Pigment epithelium-derived factor (PEDF) inhibits breast cancer metastasis by down-regulating fibronectin. Breast cancer research and treatment, 148(1), 61-72.More infoPigment epithelium-derived factor (PEDF) plays an important role in the tumor growth and metastasis inhibition. It has been reported that PEDF expression is significantly reduced in breast cancer, and associated with disease progression and poor patient outcome. However, the exact mechanism of PEDF on breast cancer metastasis including liver and lung metastasis remains unclear. The present study aims to reveal the impact of PEDF on breast cancer. The orthotopic tumor mice model inoculated by MDA-MB-231 cells stably expressing PEDF or control cells was used to assess liver and lung metastasis of breast cancer. In vitro, migration and invasion experiments were used to detect the metastatic abilities of MDA-MB-231 and SKBR3 breast cancer cells with or without overexpression of PEDF. The metastatic-related molecules including EMT makers, fibronectin, and p-AKT and p-ERK were detected by qRT-PCR, Western blot, and Fluorescent immunocytochemistry. PEDF significantly inhibited breast cancer growth and metastasis in vivo and in vitro. Mechanically, PEDF inhibited breast cancer cell migration and invasion by down-regulating fibronectin and subsequent MMP2/MMP9 reduction via p-ERK and p-AKT signaling pathways. However, PEDF had no effect on EMT conversion in the breast cancer cells which was usually involved in cancer metastasis. Furthermore, the study showed that laminin receptor mediated the down-regulation of fibronectin by PEDF. These results reported for the first time that PEDF inhibited breast cancer metastasis by down-regulating fibronectin via laminin receptor/AKT/ERK pathway. Our findings demonstrated PEDF as a dual effector in limiting breast cancer growth and metastasis and highlighted a new avenue to block breast cancer progression.
- Li, S., Zhou, T., Li, C., Dai, Z., Che, D., Yao, Y., Li, L., Ma, J., Yang, X., & Gao, G. (2014). High metastaticgastric and breast cancer cells consume oleic acid in an AMPK dependent manner. PloS one, 9(5), e97330.More infoGastric cancer and breast cancer have a clear tendency toward metastasis and invasion to the microenvironment predominantly composed of adipocytes. Oleic acid is an abundant monounsaturated fatty acid that releases from adipocytes and impinges on different energy metabolism responses. The effect and underlying mechanisms of oleic acid on highly metastatic cancer cells are not completely understood. We reported that AMP-activated protein kinase (AMPK) was obviously activated in highly aggressive carcinoma cell lines treated by oleic acid, including gastric carcinoma HGC-27 and breast carcinoma MDA-MB-231 cell lines. AMPK enhanced the rates of fatty acid oxidation and ATP production and thus significantly promoted cancer growth and migration under serum deprivation. Inactivation of AMPK attenuated these activities of oleic acid. Oleic acid inhibited cancer cell growth and survival in low metastatic carcinoma cells, such as gastric carcinoma SGC7901 and breast carcinoma MCF-7 cell lines. Pharmacological activation of AMPK rescued the cell viability by maintained ATP levels by increasing fatty acid β-oxidation. These results indicate that highly metastatic carcinoma cells could consume oleic acid to maintain malignancy in an AMPK-dependent manner. Our findings demonstrate the important contribution of fatty acid oxidation to cancer cell function.
- Zhao, Y. D., Huang, X., Yi, F., Dai, Z., Qian, Z., Tiruppathi, C., Tran, K., & Zhao, Y. Y. (2014). Endothelial FoxM1 mediates bone marrow progenitor cell-induced vascular repair and resolution of inflammation following inflammatory lung injury. Stem cells (Dayton, Ohio), 32(7), 1855-64.More infoAdult stem cell treatment is a potential novel therapeutic approach for acute respiratory distress syndrome. Given the extremely low rate of cell engraftment, it is believed that these cells exert their beneficial effects via paracrine mechanisms. However, the endogenous mediator(s) in the pulmonary vasculature remains unclear. Using the mouse model with endothelial cell (EC)-restricted disruption of FoxM1 (FoxM1 CKO), here we show that endothelial expression of the reparative transcriptional factor FoxM1 is required for the protective effects of bone marrow progenitor cells (BMPC) against LPS-induced inflammatory lung injury and mortality. BMPC treatment resulted in rapid induction of FoxM1 expression in wild type (WT) but not FoxM1 CKO lungs. BMPC-induced inhibition of lung vascular injury, resolution of lung inflammation, and survival, as seen in WT mice, were abrogated in FoxM1 CKO mice following LPS challenge. Mechanistically, BMPC treatment failed to induce lung EC proliferation in FoxM1 CKO mice, which was associated with impaired expression of FoxM1 target genes essential for cell cycle progression. We also observed that BMPC treatment enhanced endothelial barrier function in WT but not in FoxM1-deficient EC monolayers. Restoration of β-catenin expression in FoxM1-deficient ECs normalized endothelial barrier enhancement in response to BMPC treatment. These data demonstrate the requisite role of endothelial FoxM1 in the mechanism of BMPC-induced vascular repair to restore vascular integrity and accelerate resolution of inflammation, thereby promoting survival following inflammatory lung injury.
- Dai, Z., Chen, Y., Qi, W., Huang, L., Zhang, Y., Zhou, T., Yang, X., & Gao, G. (2013). Codon optimization increases human kallistatin expression in Escherichia coli. Preparative biochemistry & biotechnology, 43(1), 123-36.More infoA unique serpin, kallistatin, displays vasodilatory, antiangiogenic, anti-inflammatory, and antioxidant activity. Difficulty and low efficacy of obtaining recombinant kallistatin limit the wide investigation of its biological and pathological function. The present study employed a codon optimization algorithm to redesign the kallistatin gene and achieved a high yield of recombinant kallistatin protein. The kallistatin codons were redesigned for a more suitable Escherichia coli host without altering amino acids. Base composition and GC% content were compared between synthetic optimized kallistatin (opti-kallistatin) and wild-type kallistatin (wt-kallistatin). Both opti-kallistatin and wt-kallistatin were purified using Ni-NTA His-binding resins through fast protein liquid chromatography (FPLC). The identity and purity of kallistatin were confirmed by Coomassie blue staining, sodium dodecyl sulfate polyacrylamide gel electrophoresis (SDS-PAGE), and Western blot analysis. The output of opti-kallistatin protein was ~2-fold increase (2.09 ± 0.23 mg/L) compared to wt-kallistatin (1.05 ± 0.2 mg/L). These results suggest that more common codon optimization in the E. coli host significantly increases the yield of heterologous human protein yields. This approach will remarkably facilitate the further investigation of kallistatin in vitro and in vivo.
- Dai, Z., Lu, L., Yang, Z., Mao, Y., Lu, J., Li, C., Qi, W., Chen, Y., Yao, Y., Li, L., Chen, S., Zhang, Y., Cai, W., Yang, X., & Gao, G. (2013). Kallikrein-binding protein inhibits LPS-induced TNF-α by upregulating SOCS3 expression. Journal of cellular biochemistry, 114(5), 1020-8.More infoKallikrein-binding protein (KBP) was previously identified as a serpin family member with specific inhibitory effect on tissue kallikrein and angiogenesis, while there is little knowledge about the effects on inflammation. The aim of this study is to investigate whether KBP can suppress LPS-induced inflammatory process. Our results showed that both recombinant KBP and KBP overexpression inhibited LPS-stimulated TNF-α transcription and translation in macrophage cell line RAW264.7 and primary macrophages. Furthermore, KBP treatment protected mice from endotoxin shock and repressed serum TNF-α production, increasing survival rate of mice from 10% to 50% when compared to LPS alone. Moreover, qPCR and Western blot analysis demonstrated that both suppressor of cytokine signaling 3 (SOCS3) transcription and translation were induced by KBP treatment in the present of LPS. RNA interference assay and luciferase assay showed that SOCS3 was responsible for the down-regulation of TNF-α by KBP, rather than NF-κB subunit p65 and β-catenin. Therefore, we demonstrated that KBP suppressed LPS-induced TNF-α production via upregulating SOCS3 expression. These results present the protective effects of KBP on LPS-induced inflammation and provide novel information for the anti-inflammation mechanism.
- Dai, Z., Qi, W., Li, C., Lu, J., Mao, Y., Yao, Y., Li, L., Zhang, T., Hong, H., Li, S., Zhou, T., Yang, Z., Yang, X., Gao, G., & Cai, W. (2013). Dual regulation of adipose triglyceride lipase by pigment epithelium-derived factor: a novel mechanistic insight into progressive obesity. Molecular and cellular endocrinology, 377(1-2), 123-34.More infoBoth elevated plasma free fatty acids (FFA) and accumulating triglyceride in adipose tissue are observed in the process of obesity and insulin resistance. This contradictory phenomenon and its underlying mechanisms have not been thoroughly elucidated. Recent studies have demonstrated that pigment epithelium-derived factor (PEDF) contributes to elevated plasma FFA and insulin resistance in obese mice via the activation of adipose triglyceride lipase (ATGL). However, we found that PEDF downregulated adipose ATGL protein expression despite of enhancing lipolysis. Plasma PEDF and FFA were increased in associated with a progressive high-fat-diet, and those outcomes were also accompanied by fat accumulation and a reduction in adipose ATGL. Exogenous PEDF injection downregulated adipose ATGL protein expression and elevated plasma FFA, while endogenous PEDF neutralization significantly rescued the adipose ATGL reduction and also reduced plasma FFA in obese mice. PEDF reduced ATGL protein expression in a time- and dose-dependent manner in differentiated 3T3-L1 cells. Small interfering RNA-mediated PEDF knockdown and antibody-mediated PEDF blockage increased endogenous ATGL expression, and PEDF overexpression downregulated ATGL. PEDF resulted in a decreased half-life of ATGL and regulated ATGL degradation via ubiquitin-dependent proteasomal degradation pathway. PEDF stimulated lipolysis via ATGL using ATGL inhibitor bromoenol lactone, and PEDF also downregulated G0/G1 switch gene 2 (G0S2) expression, which is an endogenous inhibitor of ATGL activation. Overall, PEDF attenuated ATGL protein accumulation via proteasome-mediated degradation in adipocytes, and PEDF also promoted lipolysis by activating ATGL. Elevated PEDF may contribute to progressive obesity and insulin resistance via its dual regulation of ATGL.
- Dai, Z., Zhou, T., Li, C., Qi, W., Mao, Y., Lu, J., Yao, Y., Li, L., Zhang, T., Hong, H., Li, S., Cai, W., Yang, Z., Ma, J., Yang, X., & Gao, G. (2013). Intracellular pigment epithelium-derived factor contributes to triglyceride degradation. The international journal of biochemistry & cell biology, 45(9), 2076-86.More infoPigment epithelium-derived factor is well known as a secreted glycoprotein with multiple functions, such as anti-angiogenic, neuroprotective and anti-tumor activities. However, its intracellular role remains unknown. The present study was performed to demonstrate the intracellular function of pigment epithelium-derived factor on triglyceride degradation. Hepatic pigment epithelium-derived factor levels increased at the early stage and subsequently decreased after 16 weeks in high-fat-diet-fed mice compared to those in chow-fed mice. Similarly, oleic acid led to long-term downregulation of pigment epithelium-derived factor in HepG2 cells. Endogenous pigment epithelium-derived factor was an intracellular protein with cytoplasmic distribution in hepatocytes by immunostaining. Exogenous FITC-labeled pigment epithelium-derived factor could be absorbed into hepatocytes. Both signal peptide deletion and full-length pigment epithelium-derived factor transfection HeLa cells and hepatocytes promoted triglyceride degradation. Intracellular pigment epithelium-derived factor co-immunoprecipitated with adipose triglyceride lipase and promoted triglyceride degradation in an adipose triglyceride lipase-dependent manner. Additionally, pigment epithelium-derived factor bound to the C-terminal of adipose triglyceride lipase (aa268-504) and adipose triglyceride lipase-G0/G1 switch gene-2 complex simultaneously, which facilitated adipose triglyceride lipase-G0/G1 switch gene-2 translocation onto lipid droplet using bimolecular fluorescence complementation assay. Moreover, knockdown of endogenous pigment epithelium-derived factor in hepatocytes diminished triglyceride degradation. Taken together, these results indicate that hepatic pigment epithelium-derived factor was decreased in obese mice accompanied with hepatic steatosis. Intracellular pigment epithelium-derived factor binds to and facilitates adipose triglyceride lipase translocation onto lipid droplet, which promotes triglyceride degradation. These findings suggest that a decreased level of hepatic pigment epithelium-derived factor may contribute to hepatic steatosis in obesity.
- Li, C., Li, L., Cheng, R., Dai, Z., Li, C., Yao, Y., Zhou, T., Yang, Z., Gao, G., & Yang, X. (2013). Acidic/neutral amino acid residues substitution in NH2 terminal of plasminogen kringle 5 exerts enhanced effects on corneal neovascularization. Cornea, 32(5), 680-8.More infoRecent results showed that plasminogen kringle 5 (K5) has improved inhibitory effect on human umbilical vein endothelial cells (HUVECs) viability when 5 acidic amino acids in NH2 terminal outside kringle domain were replaced by 5 serine residues (mutant K5, mK5). This study was designed to identify the enhanced antiangiogenic activity of mK5 in corneal neovascularization (CNV).
- Yao, Y., Li, L., Huang, X., Gu, X., Xu, Z., Zhang, Y., Huang, L., Li, S., Dai, Z., Li, C., Zhou, T., Cai, W., Yang, Z., Gao, G., & Yang, X. (2013). SERPINA3K induces apoptosis in human colorectal cancer cells via activating the Fas/FasL/caspase-8 signaling pathway. The FEBS journal, 280(14), 3244-55.More infoSERPINA3K, also known as kallikrein-binding protein (KBP), is a serine proteinase inhibitor with anti-inflammatory and anti-angiogenic activities. Our previous studies showed that SERPINA3K inhibited proliferation in a dose-dependent manner and induced apoptosis of endothelial cells but had no influence on SGC-7901 gastric carcinoma cells or HepG2 hepatocarcinoma cells. However, it is unknown whether SERPINA3K has a direct impact on other carcinoma cells and which mechanisms are involved. In this study, we report for the first time that SERPINA3K not only decreased cell viability but also induced apoptosis in the colorectal carcinoma cell lines SW480 and HT-29. SERPINA3K-induced apoptosis of SW480 and HT-29 was rescued by interference with Fas ligand (FasL) small hairpin RNA. Moreover, SERPINA3K increased the expression of FasL and activated caspase-8. Peroxisome proliferator-activated receptor γ (PPARγ), a transcription factor of FasL, was also upregulated by SERPINA3K in a dose-dependent manner. The upregulation effect of FasL induced by SERPINA3K was reversed after interference with PPARγ small interfering RNA. These results demonstrated that SERPINA3K-induced SW480 and HT-29 cell apoptosis was mediated by the PPARγ/Fas/FasL signaling pathway. Therefore, our study provides additional insight into the direct anti-tumor function by inducing tumor cell apoptosis of SERPINA3K in colorectal tumors.
- Gu, X., Yao, Y., Cheng, R., Zhang, Y., Dai, Z., Wan, G., Yang, Z., Cai, W., Gao, G., & Yang, X. (2011). Plasminogen K5 activates mitochondrial apoptosis pathway in endothelial cells by regulating Bak and Bcl-x(L) subcellular distribution. Apoptosis : an international journal on programmed cell death, 16(8), 846-55.More infoPlasminogen Kringle 5(K5) is a proteolytic fragment of plasminogen, which displays potent anti-angiogenic activities. K5 has been shown to induce apoptosis in proliferating endothelial cells; however the exact mechanism has not been well explored. The present study was designed to elucidate the possible molecular mechanism of K5-induced endothelial cell apoptosis. Our results showed that K5 inhibited basic fibroblast growth factors activated in human umbilical vein endothelial cells (HUVECs), indicating proliferation in a dose-dependent manner and induced endothelial cell death via apoptosis. K5 exposure activated caspase 7, 8 and 9. These results suggested that both the intrinsic mitochondrial apoptosis pathway and extrinsic pathway might be involved in K5-induced apoptosis. K5 reduced mitochondrial membrane potential (MMP) of HUVECs, demonstrating mitochondrial depolarization in HUVECs. K5 increased the ratio of Bak to Bcl-x(L) on mitochondria, decreased the ratio in cytosol, and had no effect on the total amounts of these proteins. K5 also did not effect on Bax/Bcl-2 distribution. K5 increased the ratio of Bak to Bcl-x(L) on mitochondrial that resulted in mitochondrial depolarization, cytochrome c release and consequently the cleavage of caspase 9. These results suggested that K5 induces endothelial cell apoptosis at least in part via activating mitochondrial apoptosis pathway. The regulation of K5 on Bak and Bcl-x(L) distribution may play an important role in endothelial cell apoptosis. These results provide further insight into the anti-angiogenesis roles of K5 in angiogenesis-related ocular diseases and solid tumors.