Massachusetts General Hospital

The major focus of the laboratory is to unravel the molecular mechanisms that underlie the processes of growth and differentiation within intestinal epithelia. The small intestine is lined by a simple columnar epithelium in which pluripotent, proliferating crypt cells (stem cells) give rise to four distinct lineages of differentiated cells, including enterocytes (95%), goblet, and enteroendocrine cells on the villi, and paneth cells at the crypt base.

Principal Investigator:

Richard A. Hodin, MD

Members:

Madhu S. Malo, MBBS, PhD; Assistant Professor

Golam Mostafa, MD; Senior Research Technologist

Sayeda Nasrin Alam, MD; Senior Research Technologist

Kathryn Chen, MD; Postdoctoral Fellow

Sundaram Ramasamy, PhD; Postdoctoral Fellow

Nur Muhammad, MD; Postdoctoral Fellow

Farzad Ebrahimi, MD, Postdoctoral Fellow (12/2008)

Ahmad Thabet, MD, Postdoctoral Fellow (12/2008)

Omeed Moaven, MD, Postdoctoral Fellow (01/2009)

The various projects ongoing in the lab relate to understanding the differentiation process in the contexts of:

1. Normal development
2. Homeostasis within the adult
3. Pathological conditions such as starvation, cancer, and inflammatory bowel disease

Presently, we are focused on defining the mechanisms that govern gut mucosal defense and the interplay between the host and the intestinal microflora.

1. Gut development: The mammalian small intestine undergoes a very precise and complex series of morphological and biochemical changes during pre- and post-natal development. Among the most critical factors involved in this process is thyroid hormone. Animals that are hypo-thyroid or lack thyroid hormone receptors exhibit profound abnormalities within the gut mucosa. We are investigating the molecular mechanisms by which thyroid hormone exerts its effects upon gut mucosal homeostasis.
2. Gut homeostasis: The gut epithelium is a dynamic structure that undergoes a continuous cycle of self-renewal, with pluripotent stem cells located in the crypts giving rise to fully differentiated villus cells. We are studying the differentiation process of the enterocyte, the cell that comprises 95% of all villus cells and is responsible for the nutrient digestion and absorption that is critical to life. The enterocyte marker gene, intestinal alkaline phosphatase (IAP) is being used as a tool to identify and characterize transcription factors that mediate the differentiation process. Among the mechanisms that underlie gut differentiation is a specific alteration in chromatin structure. We have therefore employed novel techniques to examine the role that histone proteins play in enterocyte growth and differentiation.
3. Gut pathology: Unfortunately, the normal differentiation process goes awry under a variety of conditions, many of which are seen in surgical patients. Perhaps most notable is the gut mucosal failure that occurs with starvation and inflammation. We have identified a specific alteration in the phenotype of the enterocyte (IAP gene silencing) that appears to be a reliable marker for this gut mucosal failure. Recent work from the lab suggests that this loss of IAP expression may be a key factor in the breakdown of gut mucosal defense that is seen in starvation and other diseases.
4. Microbiotal homeostasis: Over the past millions of years, metazoans have evolved to develop and maintain a mutually beneficial symbiotic relationship with commensal microbiota. Intestinal microbiota plays a pivotal role in maintaining human health and well-being, and dysregulation of the normal homeostasis of the intestinal microbiota has been implicated in the pathogenesis of myriad disease conditions including inflammatory bowel disease (IBD), irritable bowel syndrome (IBS), colorectal carcinoma, systemic sepsis, antibiotic-associated diarrhea, etc. The human gastrointestinal tract harbors approximately 1014 bacteria that are composed of between 300 and 1,000 different species. Presently, we are attempting to decipher the fundamental mechanisms that govern the normal homeostatic number and composition of the intestinal microbiota.

We are employing IAP knockout and IAP transgenic mice in order to examine the role of this protein in regard to the gut barrier, and to lay the groundwork for IAP-based therapies that could be used clinically to help patients in the settings of severe trauma, sepsis, critical illness, and in the context of a variety of gut diseases such as IBD.

Selected Original Articles:

1. Hodin RA, Lazar MA, Wintman B, Darling DS, Koenig RJ, Larsen PR, Moore DD, Chin WW.  Identification of a thyroid hormone receptor that is pituitary-specific.  Science 1989; 244:76-79.

2. Hodin RA, Lazar MA, Chin WW.  Differential and tissue-specific regulation of the multiple rat c-erbA mRNA species by thyroid hormone. J. Clinic Invest. 1990; 85:101-105.

3. Hodin RA, Chamberlain SM, Upton M.  Thyroid hormone differentially regulates rat intestinal brush-border enzyme gene expression. Gastroenterology 1992;103:1529-1536

4. Hodin RA, Graham JR, Meng S, Upton MP.  Temporal pattern of rat small intestinal gene expression with refeeding.  Am. J. Physiol. 1994; 266:G83-G89.

5. Hodin RA, Meng S, Nguyen D. Immediate-early gene expression in EGF-stimulated intestinal epithelial cells.  J. Sur. Res. 1994; 56:500-504.

6. Hodin RA, Meng S, Shei A. Bombesin maintains enterocyte phenotype in fasted rats. Surgery 1994; 116:426-431.

7. Hodin RA, Meng S, Chamberlain SM. Thyroid hormone responsiveness is developmentally regulated in the rat small intestine: A possible role for the µ-2 receptor variant. Endocrinology 1994; 135:564-568. 

8. Hodin RA, Chamberlain SM, Meng, S. Pattern of rat intestinal brush-border enzyme gene expression changes with epithelial growth state. Am. J. Physiol. 1995; 269:C385-C391.

9. Hodin RA, Meng S, Shei A.  Differential cloning of novel intestine-specific genes whose expression is altered under conditions of villus atrophy.  J. Sur. Res. 1995; 59:115-120.

10. Hodin RA, Saldinger P, Meng S. Small bowel adaptation: counter-regulatory effects of EGF and somatostatin on the program of early gene expression. Surgery 1995;118:206-211.

11. Hodin RA, Shei A, Morin M, Meng S.  Thyroid hormone and the gut: Selective transcriptional activation of a villus-enterocyte marker. Surgery 1996; 120:138-143.

12. Hodin RA, Meng S, Archer S, Tang R. Cellular growth state differentially regulates enterocyte gene expression in butyrate treated HT-29 cells. Cell Growth & Differentiation 1996;7:647-653.

13. Meng S, Matthews JB, Hodin RA.  Downregulation of Na-K-Cl cotransporter gene expression during enterocyte differentiation along the crypt-villus axis. Surgical Forum 1996; 47:178-180.

14. Hodin RA, Meng S, Shei A.  Transcriptional activation of the human villin gene during enterocyte differentiation.  J. Gastrointest Surg, 1997;1:433-438.

15. Unno N, Wang H, Menconi MJ, Tytgat SHAJ, Larkin V, Smith M, Morin M, Hodin RA, Fink M.  Inhibition of inducible nitric oxide synthase ameliorates lipopolysaccharide-induced gut mucosal barrier dysfunction in rats. Gastroenterology, 1997; 113:1246-1257.

16. Morin M, Unno N, Hodin RA, Fink MP.  Differential expression of inducible nitric oxide synthase messenger RNA along the longitudinal and crypt-villus axes of the intestine in endotoxemic rats.  Critical Care Medicine, 1998; 26:1258-1264.

17. Matthews JB, Hassan I, Meng S, Archer S, Hrnjez BJ, Hodin RA.  Na-K-2Cl cotransporter gene expression and function during enterocyte differentiation: modulation of C1^- secretory capacity by butyrate.  J. Clinic. Invest., 1998; 101:2072-2079.

18. Archer S, Meng S, Grable P, Hodin RA.  Butyrate inhibits colon carcinoma cell growth through two distinct pathways.  Surgery, 1998; 95:6791-6796.

19. Archer SY, Meng S, Shei A, Hodin RA. p21^WAF1 is required for butyrate mediated growth inhibition of human colon cancer cells.  Proc Nat Acad Sci, 1998; 95:6791-6796.

20. Kim J, Shei A, Meng S, Hodin RA.  A novel Sp1-related cis-element involved in intestinal alkaline phosphatase gene transcription. Am. J. Physiol. 1999;276:G800-G807.

21. Chavez AM, Morin MJ, Unno N, Fink MP, Hodin RA.  Acquired interferon-g-responsiveness during Caco-2 cell differentiation: effects on iNOS gene expression. Gut 1999;44:659-665.

22. Unno N, Hodin RA, Fink MP.  Acidic conditions exacerbate interferon-g-induced intestinal epithelial hyperpermeability: Role of peroxynitrous acid. Crit Care Med  1999;27:1429-36.

23. Meng S, Wu J, Archer S, Hodin RA. Short chain fatty acids and thyroid hormone interact in regulating enterocyte gene transcription.  Surgery 1999;126:293-298.

24. Chavez AM, Menconi MJ, Hodin RA, Fink MP. Cytokine-induced intestinal epithelial hyperpermeability: role of nitric oxide. Crit Care Med, 1999;27:2246-2251.

25. Meng S, Badrinarain J, Sibley E, Fang R, Hodin RA. Thyroid hormone and the D-type cyclins interact in regulating enterocyte gene transcription. J Gastro Surg 2001; 5:49-55

26. Wu JT, Archer SY, Hinnebusch B, Meng S, Hodin RA. Transient vs. prolonged histone hyperacetylation: effects on colon cancer cell growth, differentiation, and apoptosis. Am J Physiol 2001;280:G482-G490

27. Archer SY, Johnson JJ, Kim HJ, and Hodin RA. p21 gene regulation during enterocyte differentiation. J. Sur. Res. 2001; 98: 4-8.

28. Hinnebusch BF, Ma Q, Henderson JW, Siddique A, Archer SY, Hodin RA. Enterocyte response to ischemia is dependent on differentiation state.  J Gastrointest Surg  2002;6:403-409.

29. Hinnebusch, B, Meng S, Wu J, Archer SY, Hodin RA.  The effects of short chain fatty acids on human colon cancer cell phenotype are associated with histone hyperacetylation.  J Nutrition 2002;132:1012-1017.

30. Hinnebusch, B, Henderson JW, Siddique A, Malo MS, Zhang W, Abedrapo MA, Hodin RA. Transcriptional activation of the enterocyte differentiation marker intestinal alkaline phosphatase is associated with changes in the acetylation state of histone H3 at a specific site within its promoter region in vitro. J Gastrointest Surg 2003:7:237-45

31. Siddique A, Ocuin L, Hinnebusch B, Malo MS, Abedrapo MA, Henderson JW, Zhang W, Mozumder M, Yang V, Hodin RA. Convergence of the thyroid hormone and gut-enriched kruppel-like factor pathways in the context of enterocyte differentiation.  J Gastrointest Surg, 2003; 7;1053-1061

32. Malo MS, Abedrapo M, Chen A, Mozumder M, Pushpakaran P, Alkhoury F, Zhang W, Hodin RA. Improved eukaryotic promoter-detection vectors carrying two luciferase reporter genes. Biotechniques 2003;35:1150

33. Hinnebusch B, Siddique A, Henderson JW, Malo MS, Zhang W, Athaide CP, Abedrapo MA, Chen X, Yang V, Hodin RA. Enterocyte differentiation marker intestinal alkaline phosphatase is a target gene of the gut-enriched krüppel-like factor. Am J Physiol, 2004;286:G23-G30

34. Malo MS, Zhang W, Abedrapo MA, Mozumder M, Pushpakaran P, Siddique A, Henderson JW, Hodin RA. Thyroid hormone positively regulates the enterocyte differentiation marker intestinal alkaline phosphates gene via an atypical response element. Molecular Endocrinology, 2004;18:1941-1962

35. Grikscheit T, Siddique A, Ochoa E, Srinivasan A, Alsberg E, Hodin RA, Vacanti JP. Tissue engineered small intestine improves recovery after massive small bowel resection. Annals of Surgery, 2004;240:748-754

36. Alkhoury F, Malo MS, Mozumder M, Mostafa G, Hodin RA.  Differential regulation of intestinal alkaline phosphatase gene expression by Cdx1 and Cdx2. Am J of Physiol., 2005;289:G285-290.

37. Archer SY, Johnson J, Kim H-J, Qing MA, Mou H, Vishnuvardhan D, Meng S, Hodin RA. The histone deacetylase inhibitor, butyrate downregulates cyclin B1 gene expression via a p21/waf1 dependent mechanism in human colon cancer cells. Am J Physiol   2005;289:G696-703

38. Malo MS, Pushpakaran P, Hodin RA.  A swinging cradle model for in vitro classification of different types of response elements of a nuclear receptor. Biochem and Biophys Res Comm 2005;18:490-497

39. Malo MS, Mozumder M, Chen A, Mostafa G, Hodin RA.  pFRL7: an ideal vector for eukaryotic promoter analysis. Analytical Biochem. 2006;350:307-309.

40. Malo MS, Mozumder M, Zhang XB, Biswas S, Chen A, Bai LC, Merchant JL, Hodin RA.  Intestinal alkaline phosphatase gene expression is activated by ZBP-89. Am J Physiol  2006;290:G737-746.

41. Malo MS, Biswas S, Abedrapo M, Yeh L, Chen A, Hodin RA. The pro-inflammatory cytokines, IL-1beta and TNF-alpha, inhibit intestinal alkaline phosphatase gene expression. DNA and Cell Biology 2006;25:684-695.

42. Goldberg RF, Austen, WG Jr., Zhang X, Munene G, Mostafa G, Biswas S,  McCormack M, Eberlin KR, Nguyen JT, Tatlidede HS, Warren HS,  Narisawa S, Millán JL, and Hodin RA. Intestinal alkaline phosphatase is a gut mucosal defense factor maintained by enteral nutrition. Proc Nat Acad Sci, USA 2008 Mar 4;105(9):3551-6