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Expressions of miR-22 and miR-135a in acute pancreatitis
Tao Qin1, Qiang Fu1, Yan-Feng Pan2
1Department of Hepatobiliary Pancreatic Surgery, People's Hospital of Zhengzhou University, School of Medicine, Zhengzhou University, Zhengzhou, 450003, China.
Abstract:
This study examined the expressions of miR-22 and miR-135a in rats with acute edematous pancreatitis (AEP) and their target genes in order to shed light on the involvement of miR-22 and miR-135a in the pathogenesis of acute pancreatitis (AP). The in vivo model of AEP was established by introperitoneal injection of L-arginine (150 mg/kg) in rats. The miRNA microarray analysis was used to detect the differential expression of miRNAs in pancreatic tissue in AEP and normal rats. The in vitro AEP model was established by inducing the rat pancreatic acinar cell line (AR42J) with 50 ng/mL recombinant rat TNF-α. Real-time quantitative RT-PCR was employed to detect the expression of miR-22 and miR-135a in AR42J cells. Lentiviruses carrying the miRNA mimic and anti-miRNA oligonucleotide (AMO) of miR-22 and miR-135a were transfected into the AR42J cells. The AR42J cells transfected with vehicle served as control. Western blotting was used to measure the expression of activated caspase3 and flow cytometry analysis to detect the apoptosis of AR42J cells. Targets of miR-22 and miR-135a were predicted by using TargetScan, miRanda, and TarBase. Luciferase reporter assay and quantitative real-time RT-PCR were performed to confirm whether ErbB3 and Ptk2 were the target gene of miR-22 and miR-135a, respectively. The results showed that the expression levels of miR-22 and miR-135a were obviously increased in AEP group compared with the control group in in-vivo and in-vitro models. The expression levels of miR-22 and miR-135a were elevated conspicuously and the expression levels of their target genes were reduced significantly in AR42J cells transfected with lentiviruses carrying the miRNA mimic. The apoptosis rate was much higher in the TNF-α-induced cells than in non-treated cells. The AR42J cells transfected with miRNA AMOs expressed lower level of miR-22 and miR-135a and had lower apoptosis rate, but the expression levels of ErbB3 and Ptk2 were increased obviously. It was concluded that the expression levels of miR-22 and miR-135a were elevated in AEP. Up-regulating the expression of miR-22 and miR-135a may promote the apoptosis of pancreatic acinar cells by repressing ErbB3 and Ptk2 expression in AEP.
Insights
MicroRNA-22 and microRNA-135a expressions increase in acute edematous pancreatitis (AEP). Upregulating these microRNAs promotes pancreatic acinar cell apoptosis by repressing ErbB3 and Ptk2, offering insights into acute pancreatitis pathogenesis.
Area of Science:
- Molecular Biology
- Gastroenterology
- Biochemistry
Background:
- Acute pancreatitis (AP) is a serious inflammatory condition.
- MicroRNAs (miRNAs) play crucial roles in cellular processes and disease pathogenesis.
- The specific roles of miR-22 and miR-135a in acute edematous pancreatitis (AEP) remain underexplored.
Purpose of the Study:
- To investigate the expression levels of miR-22 and miR-135a in an in vivo and in vitro model of AEP.
- To identify the target genes of miR-22 and miR-135a involved in AEP pathogenesis.
- To elucidate the mechanism by which miR-22 and miR-135a influence pancreatic acinar cell apoptosis.
Main Methods:
- Establishment of in vivo AEP rat model using L-arginine and an in vitro AEP model using AR42J cells stimulated with TNF-α.
- miRNA microarray analysis and real-time quantitative RT-PCR to detect miRNA expression.
- Lentiviral transfection with miRNA mimics and anti-miRNA oligonucleotides (AMOs), Western blotting for activated caspase-3, flow cytometry for apoptosis, and luciferase reporter assays to confirm target genes (ErbB3 and Ptk2).
Main Results:
- Expression levels of miR-22 and miR-135a were significantly increased in both in vivo and in vitro AEP models compared to controls.
- Upregulation of miR-22 and miR-135a led to decreased expression of their target genes, ErbB3 and Ptk2, respectively.
- Inhibition of miR-22 and miR-135a using AMOs reduced pancreatic acinar cell apoptosis and increased ErbB3 and Ptk2 expression.
Conclusions:
- miR-22 and miR-135a expression is elevated in acute edematous pancreatitis.
- Upregulation of miR-22 and miR-135a contributes to pancreatic acinar cell apoptosis in AEP.
- These findings suggest that miR-22 and miR-135a may promote AEP by repressing ErbB3 and Ptk2 expression, highlighting their potential as therapeutic targets.
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Acute pancreatitis is characterized by rapid inflammation of the pancreas, often caused by factors like gallstone blockage or excessive alcohol consumption. Chronic pancreatitis, on the other hand, is a slow, progressive inflammation that may result from long-term alcohol abuse, obstructions in the pancreatic duct, or genetic factors.
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