1,25(OH)2D3 supplementation alleviates gut-vascular barrier disruption via inhibition of S100B/ADAM10 pathway.

Gut-vascular barrier (GVB) is the second barrier in mucosa to control systemic dissemination of gut bacteria. Severe burns induce enteroglial cells to produce S100B and endothelial cells to generate ADAM10 and cause vitamin D3 insufficiency/deficiency and GVB disruption. It is not clear whether vitamin D3 supplementation attenuates GVB damage via regulation of S100B/ADAM10 pathway. Here, GVB disruption was induced by 30% of total body surface area scalds. Rats were treated with 1,25(OH)2D3 (0.05, 0.5 or 5 µg/kg) or S100B monoclonal antibody (S100BmAb, 10 µg/kg) or GI254023X (ADAM10 inhibitor, 100 mg/kg). Rat enteric glial cell-line CRL2690 and rat intestinal microvascular endothelial cells (RIMECs) were treated with S100B (5 µM) or plus 1,25(OH)2D3 (0.05, 0.5 or 5 µM) or GI254023X (5 µM). S100B, TNF-α, 25(OH)D3 and 1,25(OH)2D3 in serum and gut mucosa were determined by enzyme-linked immunosorbent assay. The endothelial permeability was measured using FITC-dextran 70 kDa. ADAM10 and ß-catenin expression was assayed by Western blot. The results showed that 1,25(OH)2D3 and 25(OH)D3 concentration in serum reduced whereas TNF-α and S100B in serum and gut mucosa increased in burned rats. S100BmAb, GI254023X and 1,25(OH)2D3 treatment lowered burns-increased GVB permeability. 1,25(OH)2D3 also decreased S100B concentration in serum and gut mucosa. 1,25(OH)2D3 inhibited S100B release from TNF-α-treated CRL2690 and raised ß-catenin while decreasing ADAM10 protein in S100B-treated RIMECs. 1,25(OH)2D3 and GI254023X also decreased the endothelial permeability of S100B-treated RIMECs. Collectively, these findings provide evidence that severe burns lower serum 25(OH)D3 and 1,25(OH)2D3 concentration. 1,25(OH)2D3 supplementation alleviates burns-elicited GVB disruption via inhibition of S100B/ADAM10 signaling.

Berberine decreases S100B generation to regulate gut vascular barrier permeability in mice with burn injury.

Context: Berberine (BBR) can regulate enteric glial cells (EGCs) and the gut vascular barrier (GVB).Objective: To explore whether BBR regulates GVB permeability via the S100B pathway.Materials and methods: GVB hyperpermeability in C57BL/6J mice was induced by burns or S100B enema. BBR (25 or 50 mg/kg/d, 3 d) was gavaged preburn. S100B monoclonal antibody (S100BmAb) was i.v. injected postburn. Mouse intestinal microvascular endothelial cells (MIMECs) were treated with S100B, S100B plus BBR, or Z-IETD-FMK. GVB permeability was assayed by FITC-dextran, S100B by ELISA, caspase-8, ß-catenin, occludin and PV-1 by immunoblot.Results: Burns elevated S100B in serum and in colonic mucosa to a peak (147.00 ± 4.95 ng/mL and 160.30 ± 8.50 ng/mg, respectively) at 36 h postburn, but BBR decreased burns-induced S100B in serum (126.20 ± 6.30 or 90.60 ± 3.78 ng/mL) and in mucosa (125.80 ± 12.40 or 91.20 ± 8.54 ng/mg). Burns raised GVB permeability (serum FITC-dextran 111.40 ± 8.56 pg/mL) at 48 h postburn, but BBR reduced GVB permeability (serum FITC-dextran 89.20 ± 6.98 or 68.60 ± 5.50 ng/mL). S100B enema (1 µM) aggravated burns-raised GVB permeability (142.80 ± 8.07 pg/mL) and PV-1, but the effect of S100B was antagonized by BBR. Z-IETD-FMK (5 µM) increased S100B-induced permeability to FITC-dextran (205.80 ± 9.70 to 263.80 ± 11.04 AUs) while reducing ß-catenin in MIMECs. BBR (5 µM) reduced S100B-induced permeability (104.20 ± 9.65 AUs) and increased caspase-8, ß-catenin and occludin.Discussion and conclusion: BBR decreases burns-induced GVB hyperpermeability via modulating S100B/caspase-8/ß-catenin pathway and may involve EGCs.

Berberine reduces gut-vascular barrier permeability via modulation of ApoM/S1P pathway in a model of polymicrobial sepsis.

AIMS: The hyperpermeability of gut-vascular barrier (GVB) plays a role in gut-derived sepsis. The goal of this study was to evaluate if berberine might improve hepatic apolipoprotein M (ApoM) generation and raise plasma ApoM level to protect the compromised GVB. MATERIALS AND METHODS: The compromised GVB was induced by sepsis. Hepatic ApoM mRNA and phosphoenolpyruvate carboxykinase (PEPCK) mRNA and plasma ApoM level were assayed by qRT-PCR and ELISA, respectively. The permeability of intestinal capillary in vivo and of rat intestinal microvascular endothelial cells (RIMECs) in vitro was assayed by FITC-dextran. The blood glucose was detected by a glucometer. Plasma insulin, TNF-α and IL-1ß were assayed by ELISA. The plasmalemma vesicle-associated protein-1 (PV1), ß-catenin and occludin in RIMECs were assayed by Western blot. KEY FINDINGS: Sepsis decreased hepatic ApoM mRNA and plasma ApoM level, but raised hepatic PEPCK mRNA and plasma glucose, insulin, TNF-α, and IL-1ß levels. The increased vascular endothelial permeability was abrogated by recombinant rat ApoM in vivo or ApoM-bound S1P in vitro. ApoM-bound S1P decreased PV1 but increased occludin and ß-catenin expression in LPS-treated RIMECs. Berberine in a dose-dependent manner raised hepatic ApoM mRNA and plasma ApoM level, but decreased septic hyperglycemia, insulin resistance and plasma TNF-α and IL-1ß levels. Berberine reduced sepsis-induced PEPCK and TLR4 mRNA overexpression in the liver. SIGNIFICANCE: This study demonstrated berberine inhibited TLR4-mediated hyperglycemia, insulin resistance and proinflammatory molecule production, thereby increasing ApoM gene expression and plasma ApoM. Berberine protected the damaged GVB via modulation of ApoM/S1P pathway.

Activation of IGF-1/IGFBP-3 signaling by berberine improves intestinal mucosal barrier of rats with acute endotoxemia.

Insulin-like growth factor I (IGF-I) and binding protein 3 (IGFBP-3) play a role in the maintenance of gut mucosal barrier function. Nevertheless, IGF-I/IGFBP-3 and tight junction protein (TJP) expression in small intestinal mucosa are often impaired during endotoxemia. In this model of acute endotoxemia, the regulatory effect of berberine on IGF-I/IGFBP-3 and TJP expression in ileal mucosa was evaluated. The findings revealed systemic injection of lipopolysaccharide (LPS) suppressed mRNA and protein expression of IGF-I and IGFBP-3, but berberine ameliorated their production. LPS injection inhibited occludin and claudin-1 protein generation, and this inhibitory effect of LPS was abolished by berberine. Inhibition of IGF-I/IGFBP-3 signaling by AG1024 or siRNAs reduced berberine-induced occludin and claudin-1 production. Additionally, GW9662 was found to repress berberine-induced IGF-I/IGFBP-3 expression, indicating of a cross-link between PPARγ and IGF-I/IGFBP-3 axis.

Berberine hydrochloride attenuates cyclooxygenase-2 expression in rat small intestinal mucosa during acute endotoxemia.

The effect of berberine hydrochloride (BBR) on inducible cyclooxygenase-2 (COX-2) in small intestinal mucosa and related mechanisms was investigated in a rat model of acute endotoxemia. The results showed that lipopolysaccharide (LPS) increased COX-2 expression, whereas SB202190 and BBR curtailed it. LPS increased phosphorylation of mucosal p38 MAPK and ATF2 as well as production of ATF2, whereas BBR attenuated these effects. LPS upregulated mucosal peroxisome proliferator-activated receptor gamma (PPARγ), but BBR reduced this receptor. GW9662 aggravated LPS-induced and reversed BBR-attenuated COX-2 expression. The findings showed that BBR ameliorated COX-2 overexpression partially via modulation of p38 and PPARγ pathways during acute endotoxemia.

Triptolide ameliorates Crohn's colitis is associated with inhibition of TLRs/NF-κB signaling pathway.

Growing evidence suggests that TLRs/NF-κB signaling pathway plays a critical role in the pathogenesis of Crohn's disease (CD). We have reported that triptolide, an active component from Tripterygium wilfordii Hook, showed therapeutic activity in IL-10-deficeint (IL-10-/- mice, a murine CD model. However the full mechanisms of action of this agent in CD remain largely unknown. We hypothesized that triptolide would ameliorate the experimental colitis by inhibiting TLRs/NF-κB signaling pathway. We found TLR2 and TLR4 were upregulated in IL-10-)/- mice, triptolide inhibited the TLRs/NF-κB signaling pathway in vivo. In addition, triptolide in vitro was able to downregulate the TLRs/NF-κB pathway in cultured colonic explants from CD patients. Our results confirm the therapeutic effect of triptolide in experimental colitis, and suggest it as a promising compound for CD treatment. These findings also support the possibility that targeted inhibition of TLR signaling pathway is an approach deserving further investigation as a therapeutic strategy for CD.