Inflammation In Pancreatic Cells Research Articles

MZB1 regulates cellular proliferation, mitochondrial dysfunction, and inflammation and targets the PI3K-Akt signaling pathway in acute pancreatitis

BackgroundAcute pancreatitis (AP) is a pathological condition characterized by the premature release and activation of trypsinogens and other enzyme precursors. In severe cases, the mortality rates are in the range of 20–30% and may even be as high as 50%. Though various prophylaxes are available for AP, the mechanism of its progression is unclear. Marginal zone B and B-1 cell-specific protein 1 (MZB1) is found in the endoplasmic reticulum (ER) where it is expressed exclusively in the B cells there. MZB1 promotes proliferation, inhibits apoptosis, invasion, and inflammation, and mitigates mitochondrial damage in cells. However, the importance of MZB1 in AP has not yet been determined. MethodsDifferentially expressed genes (DEGs) between healthy pancreatic cells and those affected by AP were identified using datasets from Gene Expression Omnibus (GEO) datasets. Relative differences in MZB1 expression between normal and diseased tissues and cells were validated in vivo using a rat AP model induced with 4% (w/v) sodium taurocholate and in vitro using the AR42J rat pancreatic cell line exposed to caerulein (CAE). Cell Counting Kit-8 (CCK-8) and 5-ethynyl-2`-deoxyuridine (EdU) assays were performed to detect and compare normal and pathological cell proliferation. Flow cytometry was employed to assess and compare cellular apoptosis. Quantitative reverse transcription polymerase chain reaction (qRT-PCR) and western blot (WB) were applied to evaluate the apoptotic factors Bax and Bcl. The inflammatory factors interleukin (IL)-6 and IL-1β were quantified using Enzyme-linked immunosorbent assay (ELISA) and qRT-PCR techniques. Mitochondrial function was evaluated using assays for reactive oxygen species (ROS) and tetramethylrhodamine methyl ester (TMRM). WB and qRT-PCR were utilized to measure the expression levels of the PI3K-Akt signaling pathway, followed by a rescue experiment involving the inhibitor of wortmannin. ResultsMZB1 was upregulated in the AP cases screened from the GEO datasets, the rat AP model, and the AR42J cells exposed to CAE. Overexpression of MZB1 enhanced the growth and supressed the cell death of AR42J cells while also activating the PI3K-Akt signaling pathway. MZB1 knockdown led to mitochondrial dysfunction and exacerbated inflammation. The rescue experiment demonstrated that MZB1 enhanced proliferation and inhibited apoptosis, mitochondrial dysfunction, and inflammation in pancreatic cells through the PI3K-Akt pathway. ConclusionsAP cells and tissues exhibited markedly elevated levels of MZB1 expression compared to their healthy counterparts. MZB1 overexpression promoted proliferation and supressed apoptosis, mitochondrial dysfunction, and inflammation in pancreatic cells through the positive regulation of the PI3K-Akt signaling pathway.

SHCBP1 Overexpression Aggravates Pancreatitis by Triggering the Loss of Primary Cilia.

Primary cilia are microtubule-based organelles that mediate various biological processes. Pancreatic cells are typically ciliated; however, the role of primary cilia in acute pancreatitis (AP) is largely unknown. Here, we report that the loss of primary cilia, mediated by SHCBP1 (SHC1 binding protein), exerted a provocative effect on AP. Primary cilia are extensively lost in inflamed pancreatic cells in vitro and in mouse tissues with AP in vivo. Abrogation of primary cilia aggravated lipopolysaccharide (LPS)-induced inflammation in pancreatic cells. Mechanistically, AP induced the overexpression of SHCBP1 mitotic factor, which is localized to the base of primary cilia. SHCBP1 deficiency relieved LPS- and cerulein-induced pancreatitis by preventing the loss of primary cilia in vitro and in vivo. Collectively, we reveal that inflammation-induced loss of primary cilia aggravates AP. Furthermore, abrogating SHCBP1 to prevent primary cilia loss is an efficient strategy to combat AP.

STAT3 induction by LPS and TNFα in pancreatic acinar cells

Introduction. Inflammatory mediators have been implicated in the onset and progression of acute pancreatitis (AP). The signaling pathways affected by inflammation in pancreatic cells are still largely unknown. SOCS proteins are cytokine-induced cytokine signaling inhibitors that terminate the inflammatory response. Our previous studies show that SOCS-3 mRNA levels are up regulated in response to bacterial lipopolysaccharide (LPS) or inflammation (TNFα) in acinar cells. With the addition of IL-6 or IL-1β, SOCS-3 expression is down regulated. Since SOCS-3 proteins are known to affect the JAK/STAT pathway, we hypothesized that LPS and TNFα, in combination with the proinflammatory cytokines IL-6 and IL-1β, would mediate STAT3 mRNA expression in pancreatic acinar cells. Methods. Rat pancreatic acinar cells (AR42J) were treated with either LPS (10 μg/ml) or TNF-α (10, 100, or 200 ng/ml) in the presence or absence of IL-6 (20 ng/ml) or IL-1β (10 ng/ml) for 0, 15, 30, 45, 60, 180, or 360 min. Total RNA extracted at each time point was used in multiplex RT-PCR reactions to determine STAT3 mRNA expression. Values were standardized to 18S rRNA. Results. STAT3 mRNA expression was significantly ( P < 0.05) increased by 3 h in acinar cells treated with either LPS or TNFα. At the highest concentration of TNFα, the addition of IL-6 and IL-1β significantly ( P < 0.05) enhanced STAT3 mRNA expression. When added in combination with the proinflammatory cytokines IL-6 or IL-1β, LPS-induced STAT3 expression remained elevated without further change. Conclusions. STAT3 expression was increased in response to endotoxin and proinflammatory cytokines, suggesting that STAT3 plays a role in initiating the inflammatory response in pancreatic acinar cells. These results indicate that inhibition of pancreatic STAT3 expression is a potential therapeutic strategy during the onset of acute pancreatitis.