PD-L1 blockade in mitigating severe acute pancreatitis induced pancreatic damage through modulation of immune cell apoptosis.

Acute pancreatitis (AP) is a prevalent gastrointestinal disorder. The immune response plays a crucial role in AP progression. However, the impact of immune regulatory checkpoint PD-L1 on severe acute pancreatitis (SAP) remains uncertain. Hence, this study aimed to examine the influence of PD-L1 on SAP. We assessed PD-L1 expression in neutrophils and monocytes obtained from SAP patients. We induced SAP in C57BL/6J mice, PD-L1 gene-deficient mice, and PD-L1 humanized mice using intraperitoneal injections of cerulein plus lipopolysaccharide. Prior to the initial cerulein injection, a PD-L1 inhibitor was administered. Pancreatic tissues were collected for morphological and immunohistochemical evaluation, and serum levels of amylase, lipase, and cytokines were measured. Flow cytometry analysis was performed using peripheral blood cells. The expression of PD-L1 in neutrophils and monocytes was significantly higher in SAP patients compared to healthy individuals. Likewise, the expression of PD-L1 in inflammatory cells in the peripheral blood of SAP-induced C57BL/6J mice was notably higher than in the control group. In mice with PD-L1 deficiency, SAP model exhibited lower pancreatic pathology scores, amylase, lipase, and cytokine levels compared to wild-type mice. PD-L1 deletion resulted in reduced neutrophil apoptosis, leading to an earlier peak in neutrophil apoptosis. Furthermore, it decreased early monocyte apoptosis and diminished the peak of T lymphocyte apoptosis. Within the SAP model, administration of a PD-L1 inhibitor reduced pancreatic pathology scores, amylase, lipase, and cytokine levels in both C57BL/6J mice and PD-L1 humanized mice. These findings suggest that inhibiting PD-L1 expression can alleviate the severity of SAP.

Expression profile, molecular functions, and prognostic significance of miRNAs in primary colorectal cancer stem cells.

MicroRNAs (miRNAs) are known to drive the pathogenesis of colorectal cancer (CRC) via the regulation of cancer stem cells (CSCs). We studied the miRNA expression profile of primary CSCs isolated from patients with CRC (pCRCSCs). Compared to pCRCSC-derived differentiated cells, 98 differentially expressed miRNAs were identified in pCRCSCs. Target genes encoding pCRCSC-related miRNAs were identified using a combination of miRNA target databases and miRNA-mRNA regulatory networks from the same patient. The pCRCSC-related miRNA target genes were associated with pathways contributing to malignant phenotypes, including I-kappa B kinase/NF-kappa B signaling, signal transduction by p53 class mediator, Ras signaling, and cGMP-PKG signaling. The pCRCSC-related miRNA expression signature was independently associated with poor overall survival in both the training and validation cohorts. We have thus identified several pCRCSC-related miRNAs with oncogenic potential that could serve as prognostic biomarkers for CRC.

miR-124 Intensified Oxaliplatin-Based Chemotherapy by Targeting CAPN2 in Colorectal Cancer.

Our previous study demonstrated that miR-124 was downregulated in colorectal cancer (CRC) compared with normal mucosa, and the downregulated expression of miR-124 was an independent prognostic factor in CRC patients. However, the function of miR-124 in CRC patients treated with chemotherapy is currently unclear. The aim of this study was to determine the miR-124 expression and its regulative role in oxaliplatin (L-OHP)-based chemotherapy of CRC patients. We observed that low miR-124 expression was correlated with worse overall survival (OS) in the 220 patients who received postoperative chemotherapy of 5-fluorouracil [5-FU]+leucovorin+L-OHP (FOLFOX) or capecitabine+L-OHP (XELOX). miR-124 overexpression promoted L-OHP-induced, but not 5-FU-induced, cytotoxicity and apoptosis in HT29 and SW480 cells. CAPN2 was a direct target of miR-124, and its protein expression was reduced by forced expression of miR-124. miR-124 inhibited tumorigenesis and promoted OS of mice bearing xenograft tumors, especially upon L-OHP treatment. miR-124 also promoted L-OHP-induced apoptosis and restrained CAPN2 protein expression in xenograft tumors. Our results suggest that miR-124 could be considered as both a predictor of L-OHP-based chemotherapy for personalized treatment and a therapeutic target for CRC.

Deletion Of XIAP reduces the severity of acute pancreatitis via regulation of cell death and nuclear factor-κB activity.

Severe acute pancreatitis (SAP) still remains a clinical challenge, not only for its high mortality but the uncontrolled inflammatory progression from acute pancreatitis (AP) to SAP. Cell death, including apoptosis and necrosis are critical pathology of AP, since the severity of pancreatitis correlates directly with necrosis and inversely with apoptosis Therefore, regulation of cell death from necrosis to apoptosis may have practicably therapeutic value. X-linked inhibitor of apoptosis protein (XIAP) is the best characterized member of the inhibitor of apoptosis proteins (IAP) family, but its function in AP remains unclear. In the present study, we investigated the potential role of XIAP in regulation of cell death and inflammation during acute pancreatitis. The in vivo pancreatitis model was induced by the administration of cerulein with or without lipopolysaccharide (LPS) or by the administration of l-arginine in wild-type or XIAP-deficient mice, and ex vivo model was induced by the administration of cerulein+LPS in AR42J cell line following XIAP inhibition. The severity of acute pancreatitis was determined by serum amylase activity and histological grading. XIAP deletion on cell apoptosis, necrosis and inflammatory response were examined. Caspases activities, nuclear factor-κB (NF-κB) activation and receptor-interacting protein kinase1 (RIP1) degradation were assessed by western blot. Deletion of XIAP resulted in the reduction of amylase activity, decrease of NF-κB activation and less release of TNF-α and IL-6, together with increased caspases activities and RIP1 degradation, leading to enhanced apoptosis and reduced necrosis in pancreatic acinar cells and ameliorated the severity of acute pancreatitis. Our results indicate that deletion of XIAP switches cell death away from necrosis to apoptosis and decreases the inflammatory response, effectively attenuating the severity of AP/SAP. The critical role of XIAP in cell death and inflammation suggests that inhibition of XIAP represents a potential therapeutic strategy for the treatment of acute pancreatitis.

Effects of Tocilizumab on Experimental Severe Acute Pancreatitis and Associated Acute Lung Injury.

OBJECTIVE: To examine the therapeutic effects of tocilizumab, an antibody against interleukin-6 receptor, on experimental severe acute pancreatitis and associated acute lung injury. The optimal dose of tocilizumab and the activation of interleukin-6 inflammatory signaling were also investigated. DESIGN: Randomized experiment. SETTING: Research laboratory at a university hospital. SUBJECT: Experimental severe acute pancreatitis in rats. INTERVENTIONS: Severe acute pancreatitis was induced by retrograde injection of sodium taurocholate (50 mg/kg) into the biliopancreatic duct. In dose-study, rats were administered with different doses of tocilizumab (1, 2, 4, 8, and 16 mg/kg) through the tail vein after severe acute pancreatitis induction. In safety-study, rats without severe acute pancreatitis induction were treated with high doses of tocilizumab (8, 16, 32, and 64 mg/kg). Serum and tissue samples of rats in time-study were collected for biomolecular and histologic evaluations at different time points (2, 6, 12, 18, and 24 hr). MEASUREMENTS AND MAIN RESULTS: 1) Under the administration of tocilizumab, histopathological scores of pancreas and lung were decreased, and severity parameters related to severe acute pancreatitis and associated lung injury, including serum amylase, C-reactive protein, lung surfactant protein level, and myeloperoxidase activity, were all significant alleviated in rat models. 2) Dose-study demonstrated that 2 mg/kg tocilizumab was the optimal treatment dose. 3) Basing on multi-organ pathologic evaluation, physiological and biochemical data, no adverse effect and toxicity of tocilizumab were observed in safety-study. 4) Pancreatic nuclear factor-κB and signal transducer and activator of transcription 3 were deactivated, and the serum chemokine (C-X-C motif) ligand 1 was down-regulated after tocilizumab administration. CONCLUSIONS: Our study demonstrated tocilizumab, as a marketed drug commonly used for immune-mediated diseases, was safe and effective for the treatment of experimental severe acute pancreatitis and associated acute lung injury. Our findings provide experimental evidences for potential clinical application of tocilizumab in severe acute pancreatitis and associated complications.