Anti-inflammatory and preventive activity of white mulberry root bark extract in an experimental model of pancreatitis

Pancreatitis is characterized by highly morbid inflammation in the pancreas. Currently, there is no specific drug available for pancreatitis except supportive medicines. The present study assessed the pancreato-protective effect of Morus alba root bark extract by using alcohol and cerulein-induced model of pancreatitis. The study also investigated the phytochemical profile through GC-MS and HPLC. Methanolic extract of Morus alba root bark extract (MEMARB) was subjected to GC-MS and HPLC studies. Male albino Wistar rats were administered ethanol (0%-36%) and cerulein (20 μg/kg b.wt. i.p.) with or without MEMARB. Serum lipase, amylase, caspase-1, lipid peroxidation products, glutathione and enzymatic antioxidants were determined. Histological changes in the pancreas were assessed. Cudraflavone B in MEMARB was quantified by HPLC. Significant amount of Cudraflavone B was detected by quantitative HPLC. Marked increase in the levels of serum amylase, lipase, caspase-1, IL-18 and IL-1β were observed in ethanol and cerulein administered rats than in MEMARB co-administered rats. In MEMARB co-administered rats, the antioxidant status was restored to near normal levels. Histological examinations showed that MEMARB significantly reduced the inflammatory and fibrotic changes. The results reveal the potent pancreato-protective effects of Morus alba root bark. The anti-inflammatory effect of Morus alba root bark extract might be due to the presence of various phytonutrients including Cudraflavone B.

Inhibitors of Arg-Gly-Asp-Binding Integrins Reduce Development of Pancreatic Fibrosis in Mice

BACKGROUND & AIMS

Pancreatic stellate cells (PSCs) regulate the development of chronic pancreatitis (CP) and are activated by the cytokine transforming growth factor β (TGFB). Integrins of the αv family promote TGFB signaling in mice, probably by interacting with the Arg-Gly-Asp (RGD) sequence of the TGFB latency-associated peptide, which frees TGFB to bind its cellular receptors. However, little is known about the role of integrins in the development of CP. We investigated the effects of small-molecule integrin inhibitors in a mouse model of CP.

METHODS

We induced CP in C57BL/6 female mice by repeated cerulein administration. An active RGD peptidomimetic compound (Center for World Health and Medicine [CWHM]-12) was delivered by continuous infusion, starting 3 days before or 5 days after cerulein administration began. Pancreata were collected and parenchymal atrophy, fibrosis, and activation of PSCs were assessed by histologic, gene, and protein expression analyses. We measured CWHM-12 effects on activation of TGFB in co-culture assays in which rat PSC cells (large T immortalized cells [LTC-14]) activate expression of a TGFB-sensitive promoter in reporter cells.

RESULTS

Pancreatic tissues of mice expressed messenger RNAs encoding subunits of RGD-binding integrins. Cerulein administration increased expression of these integrins, altered pancreatic cell morphology, and induced fibrosis. The integrin inhibitor CWHM-12 decreased acinar cell atrophy and loss, and substantially reduced fibrosis, activation of PSCs, and expression of genes regulated by TGFB. CWHM-12 also reduced established fibrosis in mice and blocked activation of TGFB in cultured cells.

CONCLUSIONS

Based on studies of a mouse model of CP and cultured PSCs, integrins that bind RGD sequences activate PSCs and promote the development of pancreatic fibrogenesis in mice. Small-molecule antagonists of this interaction might be developed for treatment of pancreatic fibrotic diseases.

P2X7 Receptor Mediates Spinal Microglia Activation of Visceral Hyperalgesia in a Rat Model of Chronic Pancreatitis

BACKGROUND & AIMS

Molecular mechanisms underlying the activated spinal microglia in association with the pain in chronic pancreatitis (CP) remain unknown. We tested whether P2X7R on spinal microglia mediates the pathogenesis of visceral pain using a CP rat model.

METHODS

The CP model was induced via intraductal injection of 2% trinitrobenzene sulfonic acid into male Sprague-Dawley rats. Hyperalgesia was assessed based on the mechanical sensitivity to Von-Frey filaments (VFFs), and nocifensive behaviors were measured in response to electrical stimulation of the pancreas. Three weeks after CP induction, spinal cord samples were harvested for immunostaining, immunoblot, and real-time polymerase chain reaction analyses of the P2X7R. Changes in nocifensive behaviors and associated molecular effectors were assessed by blocking spinal cord P2X7R pharmacologically using the selective P2X7R antagonist brilliant blue G (BBG) or genetically using short interfering RNA (siRNA).

RESULTS

CP induced a significant up-regulation of spinal P2X7R expression, which colocalized with a microglial marker (OX-42). Intrathecal administration of BBG significantly attenuated CP-related visceral hyperalgesia in response to VFF-mediated or electrical stimulation of the pancreas, which was associated with suppressed spinal expression of P2X7R and inhibited activation of spinal microglia. Intrathecal injection of siRNA to knock down P2X7R expression in the spinal cord would suppress the nociceptive behaviors in CP rats.

CONCLUSIONS

Spinal microglia P2X7R mediates central sensitization of chronic visceral pain in CP. BBG may represent an effective drug for the treatment of chronic pain in CP patients.

CD4+ T cells potently induce epithelial-mesenchymal-transition in premalignant and malignant pancreatic ductal epithelial cells-novel implications of CD4+ T cells in pancreatic cancer development

Chronic pancreatitis (CP) is a risk factor of pancreatic ductal adenocarcinoma (PDAC) and characterized by a pronounced desmoplastic reaction with CD4⁺ T cells accounting for the majority of the stromal T cell infiltrate. Epithelial-mesenchymal-transition (EMT) is a critical process for metastasis by which epithelial/carcinoma cells become enabled to disseminate probably prior to tumor formation. To investigate whether CD4⁺ T cells induce EMT in human pancreatic ductal epithelial cells, premalignant H6c7 cells were mono- or co-cultured with human CD4⁺CD25⁺CD127^-CD49d^- regulatory T cells (T-regs) or CD4⁺CD25^- T-effector cells (T-effs) being isolated by negative magnetic bead separation from blood of healthy donors. Particularly in the presence of activated T-effs, H6c7 cells acquired a spindle-shaped morphology, reduced E-cadherin expression, and elevated expression of the mesenchymal proteins vimentin, L1CAM, and ZEB-1. This was accompanied by an increased invasive behavior. Moreover, activated T-effs exerted similar effects in the PDAC cell line T3M4. Blocking of TNF-α and IL-6 being released at greater amounts into supernatants during co-cultures with activated T-effs attenuated the EMT-associated alterations in H6c7 cells. Supporting these findings, EMT-associated alterations (exemplified by reduced E-cadherin expression and enhanced expression of vimentin and L1CAM) were predominantly detected in ductal epithelium of CP tissues surrounded by a dense stroma enriched with CD4⁺ T cells. Overall this study points to a novel role of CD4⁺ T cells beyond their immune function in pancreatic tumorigenesis and underscores the view that EMT induction in pancreatic ductal epithelial cells represents an early event in PDAC development being essentially promoted by inflammatory processes.