Long noncoding RNA myocardial infarction–associated transcript regulated the pancreatic stellate cell activation to promote the fibrosis process of chronic pancreatitis

Abstract

Background: Long noncoding RNAs (lncRNAs) play crucial roles in fibrosis process. In our previous RNA-seq study, we found that lncRNA myocardial infarction-associated transcript (MIAT) was differentially expressed in pancreatic tissues of chronic pancreatitis (CP) patients. However, the function of MIAT in CP remains unknown. This study was aimed to investigate the function and underlying mechanism of MIAT in pancreatic fibrosis. Materials and Methods: The expression levels of MIAT, miR-216a-3p, cyclooxygenase 2 (COX-2), α-smooth muscle actin (α-SMA), and collagen I were estimated by Western blot analysis and qualitative reverse transcription polymerase chain reaction. The relationships between miR-216a-3p, MIAT, and COX-2 were confirmed by luciferase reporter assay. The proliferation of human pancreatic stellate cells (HPaSteCs) was detected by cell counting kit-8 assay.Results: We found that MIAT, along with the levels of fibrosis-related proteins α-SMA and collagen I, as well as COX-2 were upregulated, while miR-216a-3p was downregulated in transforming growth factor (TGF)-β1-stimulated HPaS-teCs. Mechanistically, MIAT acted as a molecular sponge for miR-216a-3p. Furthermore, we identified COX-2 as a direct target of miR-126a-3p. Additionally, MIAT overturned the inhibitory effect of miR-216a-3p overexpression and COX-2 knockdown on the activation and proliferation of HPaSteCs. Conclusion: Our study provided mechanistic insights into a critical role for MIAT as a miRNA sponge in CP. K E Y W O R D S chronic pancreatitis, human pancreatic stellate cells, long noncoding RNA, myocardial infarction-associated transcript J Cell Biochem. 2019;120:9547-9555.wileyonlinelibrary.com/journal/jcb noncoding RNA myocardial infarction-associated transcript regulated the pancreatic stellate cell activation to promote the fibrosis process of chronic pancreatitis. J Cell Biochem. 2019;120:9547-9555.

Molecular Mechanism of Pancreatic Stellate Cells Activation in Chronic Pancreatitis and Pancreatic Cancer

“…Wang et al reported that the inhibition of syntaxin-12 lncRNA, which making miR-148a upregulated and Smad5 decreased, ultimately resulting in the suppression of PSC activation [60]. Liu et al had a similar discovery that lncRNA myocardial infarction-associated transcript contributed to PSCs activation through suppressing miR-216a-3pmediated COX-2, which finally leading to pancreatic fibrosis [61]. Same studies also uncover the inhibitory effect of miR-200a in PSCs activation [62].…”

Hic‐5 deficiency protects cerulein‐induced chronic pancreatitis via down‐regulation of the NF‐κB (p65)/IL‐6 signalling pathway

“…[30][31][32] A large body of evidence from both animal and human studies demonstrate that the TGF-β signalling pathway mediates the progression of fibrotic processes. 29,33,34 Hic-5 was originally characterized as a TGF-βinducible gene. Our results indicate that quiescent PSCs exhibit extremely low expression levels of Hic-5, activation with TGF-β leads to a significant up-regulation of Hic-5 and knocking out Hic-5 did not alter the expression levels of TGF-β in our mice model of CP.…”

“…Immunohistochemical analysis of the pancreas sections indicated that the expression of α-SMA, a marker for activated PSCs, 29 was significantly decreased in the pancreas of Hic-5 KO mice treated with cerulein compared with the wild-type mice treated with cerulein ( Figure 4A). We evaluated the mRNA levels of fibrosis-associated and Timp1 in the pancreas of the Hic-5 KO mice were significantly lower than those of the wild-type mice, following cerulein treatment ( Figure 4B).…”

“…The activation of PSCs plays a crucial role in promoting ECM production and pancreatic fibrosis. 29 Therefore, we assessed whether Hic-5 was required for the activation of PSCs in vitro in primary PSCs isolated from the pancreas of wild-type and Hic-5 KO mice. The PSCs were identified by morphological features and immunofluorescence staining for α-SMA ( Figure 5C).…”

“…After culturing for 12 hours, Hic-5 expression was detected in pancreatic stellate cells, but not in acinar cells (Figure 5A). The activation of PSCs plays a crucial role in promoting ECM production and pancreatic fibrosis 29. Therefore, we assessed whether Hic-5 was required for the activation of PSCs in vitro in primary PSCs isolated from the pancreas of wild-type and Hic-5 KO mice.…”