Immune Studies in IBD//

Publications

Eissa N, Elgazzar O, Hussein H, Hendy GN, Bernstein CN, Ghia JE. Pancreastatin reduces alternatively activated macrophages, disrupts the epithelial homeostasis and aggravates colonic inflammation. A descriptive analysis. Biomedicines 2021; 9:134.

Ulcerative colitis (UC) is characterized by modifying alternatively activated macrophages and epithelial homeostasis. Chromogranin-A released by enterochromaffin cells, is elevated in UC and is implicated in inflammation progression. CHGA can be cleaved into several derived peptides, including pancreastatin, which is involved in proinflammatory mechanisms. Previously, we showed that the deletion of Chga decreased the onset and severity of colitis correlated with an increase in alternatively activated macrophages and epithelial cells' functions. Here, we investigated pancreastatin activity in colonic biopsies of participants with active UC and investigated pancreastatin treatment in dextran sulfate sodium (DSS)-induced colitis using Chga-/- mice, macrophages, and a human colonic epithelial cells line. We found that the colonic protein expression of pancreastatin correlated negatively with mRNA expression of alternatively activated macrophages markers and tight junction proteins and positively with mRNA expression of interleukin (IL)-8, IL18, and collagen in human. In a preclinical setting, intra-rectal administration of pancreastatin aggravated DSS-induced colitis by decreasing alternatively activated macrophages' functions, enhancing colonic collagen deposition and disrupting epithelial homeostasis in Chga+/+ and Chga-/- mice. This effect was associated with a significant reduction in AAM markers, increased colonic IL-18 release, and decreased tight junction proteins' gene expression. In vitro, pancreastatin reduced Chga+/+ and Chga-/- alternatively activated macrophages polarization and decreased anti-inflammatory mediators' production. Conditioned medium harvested from PST-treated Chga+/+ and Chga-/- alternatively activated macrophages reduced Caco-2 cell migration, viability, proliferation, and mRNA levels of tight junction proteins and increased oxidative stress-induced apoptosis and proinflammatory cytokines release. In conclusion, pancreastatin is a Chromogranin-A proinflammatory peptide that enhances the severity of colitis and the inflammatory process via decreasing alternatively activated macrophages functions and disrupting epithelial homeostasis.

Eissa N, Elgazzar O, Hussein H, Hendy GN, Bernstein CN, Ghia JE. Pancreastatin reduces alternatively activated macrophages, disrupts the epithelial homeostasis and aggravates colonic inflammation. a descriptive analysis. Biomedicines 2021 Feb 1;9(2):134.

 

Ulcerative colitis is characterized by modifying alternatively activated macrophages and epithelial homeostasis. Chromogranin-A, released by enterochromaffin cells, is elevated in ulcerative colitis and is implicated in inflammation progression. chromogranin-A can be cleaved into several derived peptides, including pancreastatin, which is involved in proinflammatory mechanisms. Previously, we showed that the deletion of Chga decreased the onset and severity of colitis correlated with an increase in alternatively activated macrophages and epithelial cells' functions. Here, we investigated pancreastatin activity in colonic biopsies of participants with active ulcerative colitis and investigated pancreastatin treatment in dextran sulfate sodium (DSS)-induced colitis using Chga-/- mice, macrophages, and a human colonic epithelial cells line. We found that the colonic protein expression of pancreastatin correlated negatively with mRNA expression of alternatively activated macrophages markers and tight junction (TJ) proteins and positively with mRNA expression of interleukin (IL)-8, IL18, and collagen in human. In a preclinical setting, intra-rectal administration of pancreastatin aggravated DSS-induced colitis by decreasing alternatively activated macrophages 's functions, enhancing colonic collagen deposition and disrupting epithelial homeostasis in Chga+/+ and Chga-/- mice. This effect was associated with a significant reduction in alternatively activated macrophages markers, increased colonic IL-18 release, and decreased TJ proteins' gene expression. In vitro, pancreastatin reduced Chga+/+ and Chga-/- alternatively activated macrophage polarization and decreased anti-inflammatory mediators' production. Conditioned medium harvested from PST-treated Chga+/+ and Chga-/- alternatively activated macrophages reduced Caco-2 cell migration, viability, proliferation, and mRNA levels of TJ proteins and increased oxidative stress-induced apoptosis and proinflammatory cytokines release.

In conclusion, pancreastatin is a chromogranin-A proinflammatory peptide that enhances the severity of colitis and the inflammatory process via decreasing alternatively activated macrophages functions and disrupting epithelial homeostasis.

 

 

Eissa N, Hussein H, Tshikudi D, Hendy GN, Bernstein CN, Ghia JE. Interdependence between chromogranin-A, alternatively activated macrophages, tight junction proteins and the epithelial functions. A human and in-vivo/in-vitro descriptive study. International Journal of Molecular Sciences 2020; Oct 27;21(21):7976.

Ulcerative colitis is characterized by altered chromogranin-A, alternatively activated macrophages (M2) and intestinal epithelial cells (IECs). We previously demonstrated that chromogranin-A is implicated in colitis progression by regulating the macrophages. Here, we investigated the interplay between chromogranin-A, M2, tight junctions (TJ) and IECs in an inflammatory environment. Correlations between chromogranin-A mRNA expression of and TJ proteins mRNA expressions of (Occludin [OCLN], zonula occludens-1 [ZO1], Claudin-1 [CLDN1]), epithelial associated cytokines (interleukin [IL]-8, IL-18), and collagen (COL1A2) were determined in human colonic mucosal biopsies isolated from active UC and healthy patients. Acute ulcerative colitis-like colitis (5% dextran sulphate sodium [DSS], five days) was induced in chromogranin-A -C57BL/6-deficient (chromogranin-A-/-) and wild type (chromogranin-A +/+) mice. Colla2 TJ proteins, IL-18 mRNA expression and collagen deposition were determined in whole colonic sections. Naïve chromogranin-A-/- and chromogranin-A+/+ peritoneal macrophages were isolated and exposed six hours to IL-4/IL-13 (20 ng/mL) to promote M2 and generate M2-conditioned supernatant. Caco-2 epithelial cells were cultured in the presence of chromogranin-A-/- and chromogranin-A+/+ non- or M2-conditioned supernatant for 24 h then exposed to 5% DSS for 24 h, and their functional properties were assessed. In humans, chromogranin-A mRNA correlated positively with COL1A2, IL-8 and IL-18, and negatively with TJ proteins mRNA markers. In the experimental model, the deletion of chromogranin-A reduced IL-18 mRNA and its release, COL1A2 mRNA and colonic collagen deposition, and maintained colonic TJ proteins. Chromogranin-A-/- M2-conditioned supernatant protected caco-2 cells from DSS and oxidative stress injuries by improving caco-2 cells functions (proliferation, viability, wound healing) and by decreasing the release of IL-8 and IL-18 and by maintaining the levels of TJ proteins, and when compared with chromogranin-A+/+ M2-conditioned supernatant.

 

We concluded that chromogranin-A contributes to the development of intestinal inflammation through the regulation of M2 and epithelial cells. Targeting chromogranin-A may lead to novel biomarkers and therapeutic strategies in ulcerative colitis.

Eissa N, Hussein H, Diarra A, Kapoor K, Gounni AS, Bernstein CN, Ghia JE. Semaphorin 3E regulates apoptosis in the intestinal epithelium during the development of colitis. Biochemical Pharmacology 2019; 166:264-273. 

 

Semaphorin 3E is a protein that regulates various biological processes including immune responses. However, its role in the pathophysiology of colitis is not fully known. We investigated the role of Semaphorin 3E in intestinal epithelial cells activation, using biopsies from patients with active ulcerative colitis (UC), a mouse model of UC, and an in-vitro model of intestinal mucosal healing. In this study, we confirmed that the mRNA level of Semaphorin 3E is reduced significantly in patients with UC and demonstrated a negative linear association between Semaphorin 3E mRNA and p53-associated genes. In mice, genetic deletion of Sema3e (gene for Semaphorin 3E) resulted in an increase in onset and severity of colitis, p53-associated genes, apoptosis, and interleukin-1b production. Recombinant Semaphorin 3E treatment protected against colitis and decreased these effects. Furthermore, in stimulated epithelial cells, recombinant Semaphorin 3E treatment enhanced wound healing, resistance to oxidative stress and decreased apoptosis and p53-associated genes.

Together, these findings identify Semaphorin 3E as a novel regulator in intestinal inflammation that regulates intestinal epithelial cells apoptosis and suggest a potential novel approach to treat UC.