Secretin Stimulates Biliary Cell Proliferation by Regulating Expression of MicroRNA 125b and MicroRNA let7a in Mice

Abstract

Background & Aims Proliferating cholangiocytes secrete and respond to neuroendocrine hormones including secretin. We investigated whether secretin secreted by S cells and cholangiocytes stimulates biliary proliferation in mice. Methods Cholestasis was induced in secretin knockout (Sct−/−) and wild-type (control) mice by bile-duct ligation (BDL). At days 3 and 7 after BDL, control and Sct−/− mice received tail-vein injections of morpholinos against microRNA 125b or let7a. One week later, liver tissues and cholangiocytes were collected; immunohistochemical, immnoblot, luciferase reporter and real-time PCR assays were performed. Intrahepatic bile duct mass (IBDM) and proliferation were measured. Secretin secretion was measured in conditioned media from cholangiocytes and S cells, and in serum and bile. Results Secretin secretion was increased in supernatants from cholangiocytes and S cells and in serum and bile following BDL in control mice. BDL Sct−/− mice had lower IBDM, reduced proliferation, and reduced production of vascular endothelial growth factor A (VEGFA) and nerve growth factor (NGF) compared with BDL control. BDL and control mice given morpholinos against microRNA 125b or let7a had increased IBDM. Livers of mice given morpholinos against microRNA 125b had increased expression of VEGFA while those treated with morpholinos against microRNA let7a had increased expression of NGF. Secretin regulated VEGF and NGF expression that negatively correlated with microRNA 125b and let7a levels in liver tissue. Conclusions Following liver injury, secretin produced by cholangiocytes and S cells reduces microRNA 125b and let7a levels, resulting in upregulation of VEGF and NGF. Modulation of cholangiocyte expression of secretin could be a therapeutic approach for biliary diseases.

Inhibition of mast cell-derived histamine secretion by cromolyn sodium treatment decreases biliary hyperplasia in cholestatic rodents

“…Autocrine/paracrine regulation of biliary proliferation is highly complex and involves numerous factors, including vascular endothelial growth factor (VEGF), serotonin, secretin and histamine. 26,34,44,45 After BDL, the biliary epithelium proliferates and cholangiocytes secrete abundant amounts of these neuroendocrine factors to support the increased demands of the proliferating biliary tree. 26,34,44 We have previously shown that (i) histamine treatment increases normal rat cholangiocyte proliferation; 28 and (ii) after BDL, histamine levels are increased in both serum and cholangiocyte supernatant.…”

“…26,34,44,45 After BDL, the biliary epithelium proliferates and cholangiocytes secrete abundant amounts of these neuroendocrine factors to support the increased demands of the proliferating biliary tree. 26,34,44 We have previously shown that (i) histamine treatment increases normal rat cholangiocyte proliferation; 28 and (ii) after BDL, histamine levels are increased in both serum and cholangiocyte supernatant. 7 Autocrine regulation by histamine has been demonstrated in both biliary hyperplasia and neoplasia, as evidenced by our finding that inhibition of HDC decreases biliary growth.…”

“…33 Western blotting was performed in isolated cholangiocytes for PCNA expression with 20 mg of protein; b-actin was used as the housekeeping gene. 28,34 Band intensity was determined on the Odyssey system from LI-COR Biosciences (Lincoln, NE, USA), Model no. 9120.…”

Disrupted Murine Gut–to–Human Liver Signaling Alters Bile Acid Homeostasis in Humanized Mouse Liver Models

“…To examine further whether proliferation of hepatocytes had influenced cholangiocyte growth and intrahepatic bile acid mass, chemokine (C-X-C motif) ligand 16 (Cxcl16) (Omenetti et al, 2009) and other vascular endothelial growth factors (Vegf-a and Vegf-c) (Glaser et al, 2014;Meng et al, 2014), key cell-growth proliferators in cholangiocytes, were measured (Fig. 3B).…”

Post-translational Regulation of the Type III Inositol 1,4,5-Trisphosphate Receptor by miRNA-506

“…miR-30b/c, miR-195, miR-200a, miR-320, miR-365, and miR-133a/b were found to be among the principal downregulated miRNAs (29). Additionally, Glaser et al (30) showed that secretin regulation of VEGFA and NGF (mediating cholangiocyte proliferation in bile duct ligated mice) occurred through negative regulation of miR-125b and miRlet7a. Although our results indicate that none of these miRNAs would directly regulate InsP 3 R3, based on the TargetScan algorithm, it is still possible that they regulate InsP 3 R3 indirectly or the algorithms alone currently cannot precisely predict all the miR targets.…”