- Associate Professor, Pediatrics - (Research Scholar Track)
- Associate Professor, Physiological Sciences - GIDP
No activities entered.
No activities entered.
Senior CapstoneMCB 498 (Spring 2020)
Senior CapstoneMCB 498 (Fall 2019)
Independent StudyMCB 499 (Spring 2019)
Independent StudyMCB 399 (Fall 2018)
- Xu, H., & Ghishan, F. (2018). Molecular Physiology of Gastrointestinal Function during Development. In Physiology of the Gastrointestinal Tract.
- Xu, H., Ghishan, F., & Kiela, P. (2018). SLC9 Gene Family: Function, Expression, and Regulation.. In Compr Physiol.
- Xu, H., Li, J., Chen, H., & Ghishan, F. (2018). NHE8 Deficiency Promotes Colitis-Associated Cancer in Mice via Expansion of Lgr5-Expressing Cells.. Cell Mol Gastroenterol Hepatol..
- Li, X., Cai, L., Xu, H., Geng, C., Lu, J., Tao, L., Sun, D., Ghishan, F. K., & Wang, C. (2016). Somatostatin regulates NHE8 protein expression via the ERK1/2 MAPK pathway in DSS-induced colitis mice. American journal of physiology. Gastrointestinal and liver physiology, 311(5), G954-G963.More infoPrevious studies reported that administration of somatostatin (SST) to human patients mitigated their diarrheal symptoms. Octreotide (an analog of SST) treatment in animals resulted in upregulation of sodium/hydrogen exchanger 8 (NHE8). NHE8 is important for water/sodium absorption in the intestine, and loss of NHE8 function results in mucosal injury. Thus we hypothesized that NHE8 expression is inhibited during colitis and that SST treatment during pathological conditions can restore NHE8 expression. Our data showed for the first time that NHE8 is expressed in the human colonic tissue and that NHE8 expression is decreased in ulcerative colitis (UC) patients. We also found that octreotide could stimulate colonic NHE8 expression in colitic mice. Furthermore, the somatostatin receptor 2 (SSTR2) agonist seglitide and the somatostatin receptor 5 (SSTR5) agonist L-817,818 could restore NHE8 expression via its role in suppressing ERK1/2 phosphorylation. Our study uncovered a novel mechanism of SST stimulation of NHE8 expression in colitis.
- Xu, H., Li, Q., Zhao, Y., Li, J., & Ghishan, F. K. (2016). Intestinal NHE8 is highly expressed in goblet cells and its expression is subject to TNF-α regulation. American journal of physiology. Gastrointestinal and liver physiology, 310(2), G64-9.More infoWhile the intestine plays an important role in digestion and absorption, the mucus lining the epithelium represents a pivotal function in mucosal protection. Goblet cells are scattered in both the crypts and among enterocytes, and they secrete an important component of mucus, mucin. We have reported that sodium/hydrogen exchanger (NHE) 8 is a novel player in mucosal protection, since loss of NHE8 function resulted in reduced mucin production and increased bacterial adhesion. While NHE8 has been shown to be expressed in enterocytes and its expression is reduced during intestinal inflammation, nothing is known about the role of NHE8 in goblet cells. This current study is designed to define the expression of NHE8 and the role of TNF-α in the regulation of NHE8 in goblet cells. Using HT29-MTX cells as an in vitro model, we detected abundant NHE8 mRNA in goblet cells. Immunohistochemical staining localized NHE8 protein on the plasma membrane and in the intracellular compartments in goblet cells. Furthermore, NHE8 expression in goblet cells is regulated by the proinflammatory cytokine TNF-α. The expression of NHE8 in HT29-MTX cells was significantly reduced at both mRNA and protein levels in the presence of TNF-α. This inhibition of NHE8 mRNA expression could be blocked by the transcriptional inhibitor actinomycin D. Promoter reporter assay showed that NHE8 promoter activity was indeed reduced by TNF-α. Mechanistically, TNF-α reduced Sp3 protein binding to the human NHE8 basal promoter region. Therefore, NHE8 is expressed in goblet cells, and the inflammatory cytokine TNF-α downregulates NHE8 expression by a transcriptional mechanism.
- Xu, H., Bernardazzi, C., & Ghishan, F. (2018, December). EFFECTS OF BUTYRATE SUPPLEMENTATION ON NHE8KO MICE. DDW 2019.
- Xu, H., Bernardazzi, C., Li, J., & Ghishan, F. (2018, December). LOSS OF NHE8 IMPAIRS GOBLET CELL DIFFERENTIATION/MATURATION IN THE COLON. DDW 2019.
- Xu, H. (2018, Sept). Short Chain Fatty Acid and Digestive Health. 2018 IFFSH 食品科学与健康国际学术论坛. Changsha, China: 湖南农业大学.
- Xu, H., Li, J., & Ghishan, F. (2017, May). LOSS OF NHE8 EXPRESSION IMPAIRS CRYPT FUNCTION IN THE COLON. DDW.
- Gurney, M. A., Laubitz, D., Xu, H., Ghishan, F. K., & Kiela, P. R. (2016, April). Intrinsic Effects of Reduced NHE3 Activity in Intestinal Epithelial Cells. Digestive Disease Week. San Diego, USA: American Gastroenterological Association.
- Xu, H., Li, J., & Ghishan, F. (2016, Apr). NHE8 is required for goblet cell function. Experimental Biology.
- Xu, H., Li, J., & Ghishan, F. (2016, May). NHE8 has a protective role from colon cancer development. Digestive Disease Week.
- Xu, H., Li, J., Chen, H., & Ghishan, F. (2018, June 2-5). INCREASED COLONIC LGR5 EXPRESSION IS ASSOCIATED WITH NHE8 DEFICIENCY. DDW2018.