miR‑206 regulates alveolar type�II epithelial cell Cx43 expression in sepsis‑induced acute lung injury

Abstract

The present study investigated the relationship between connexin 43 (Cx43) expression in alveolar type II epithelial cells (ATII) and alveolar air-blood barrier permeability, and the effect of microRNA-206 (miR-206) on the expression of Cx43 in sepsis-induced acute lung injury. For the in vivo study, rats were divided into the sham, caecum ligation and perforation (CLP), CLP+Cx43 inhibitors (Cx43-In) and CLP+miR-206 analogs (miR-206-Mi) groups. CLP method was used to prepare an acute lung injury model of sepsis. Following successful modeling, lung tissue was collected for hematoxylin and eosin (HE) staining, and the wet to dry weight ratio (W/D) and protein content in bronchoalveolar lavage fluid (BALF) were detected. Cx43 expression in lung tissue was determined by immunohistochemistry and western blot analysis. Additionally, miR-206 and Cx43 expression levels in lung tissue were detected by reverse transcription-quantitative polymerase chain reaction. Rat ATII cells were cultured in Transwells plates to form monolayers, then treated with Cx43 mRNA inhibitors or miR-206 analogs. The cell monolayers were then stimulated with lipopolysaccharide and their permeability was evaluated by detecting fluorescein-labeled dextran at the lower chamber of the Transwells. The dual luciferase reporter gene assay was used to investigate whether miR-206 targeted the 3′ untranslated region of Cx43 mRNA to regulate Cx43 expression, thereby regulating the permeability of the alveolar air-blood barrier. Results demonstrated that the CLP method induced damage to the alveolar structure, thickened the alveolar wall, caused hyperemia and hemorrhage in the pulmonary interstitium and caused infiltration of inflammatory cells. Edema in the pulmonary interstitium and alveolar space, exudation of neutrophilic granulocyte and pink edema fluid in alveolar cavities were also observed. W/D ratio, the BALF protein content, and expression of Cx43mRNA and Cx43 were increased significantly, whilst miR-206 expression decreased compared with the control group. The lung tissue inflammatory response was attenuated, and the W/D ratio and BALF protein content decreased in the Cx43-In and miR-206-Mi groups compared with the CLP group. Moreover, Cx43 mRNA and protein expression were decreased significantly in the Cx43-In and miR-206-Mi groups. In addition, the dual luciferase reporter gene assay determined that the untranslated region of Cx43 mRNA had a complementary sequence to miR-206. Of note, Cx43 mRNA expression in the miR-206-Mi group was not significantly decreased in vitro . In conclusion, the increase in ATII cell Cx43 expression during sepsis-induced acute lung injury resulted in an increase in the permeability of the alveolar air-blood barrier. miR-206 targeted the Cx43 mRNA 3′untranslated region to downregulate Cx43 expression, which further improved the permeability of the alveolar air-blood barrier.

Sufentanil attenuates inflammation and oxidative stress in sepsis-induced acute lung injury by downregulating KNG1 expression

“…Sepsis can result in multiple organ failure and is considered a leading cause of mortality in intensive care unit patients ( 21 ). The lung serves as the most susceptible target organ in sepsis that can further develop into life-threating acute respiratory distress syndrome (ARDS), which is the principle risk factor for mortality ( 22 , 23 ). The present study demonstrated that sufentanil protected against sepsis-induced ALI by regulating KNG1-mediated NF-κB and Nrf2/HO-1 signaling.…”

miR-206 as a prognostic and sensitivity biomarker for platinum chemotherapy in epithelial ovarian cancer

“…Cx43 has been found to be a direct target of miR-206 in many cells, including smooth muscle cells [ 14 ], myocardial cells [ 15 ], type II alveolar epithelial cells [ 15 ] and breast cancer cells [ 16 ]. Cx43 is a gap junction protein that promotes cisplatin cytotoxicity [ 17 ].…”

“…Many proteins have been reported to be directly targeted by miR-206, including estrogen receptor 1 (ESR1) [ 6 ], MET [ 39 ], NOTCH 3 [ 6 , 39 ], HDAC4 [ 27 ], Gadd45β [ 40 ], and Connexin 43 (Cx43) [ 14 , 15 , 41 ]. Among these targets, Cx43 is a well-defined target molecule of miR-206 in many types of cells, including smooth muscle cells [ 14 ], myocardial cells [ 15 ], type II alveolar epithelial cells [ 15 ] and breast cancer cells [ 16 ]. Cx43 is ubiquitous in cells and is reduced in a variety of tumor cells [ 16 ].…”

Upregulation of endothelial cell-derived exosomal microRNA-125b-5p protects from sepsis-induced acute lung injury by inhibiting topoisomerase II alpha

“…HE staining of the lower lobes of the right lungs was performed as previously described [ 7 ]. The tissues were observed and photographed under a microscope.…”

“…MiRNAs are able to modulate protein expression via binding to 3′-untranslation region (3′-UTR) in the target mRNA [ 5 ]. Some particular miRNAs, such as miR-145 [ 6 ] and miR-206 [ 7 ] have been revealed to be involved in the development of sepsis-induced ALI. miR-125b-5p has been verified to be abnormally expressed in sepsis [ 8 ] and impact of miR-125b on lipopolysaccharide (LPS)-induced ALI has been previously studied [ 9 ], while role of miR-125b-5p in the development of sepsis-induced ALI has not been explored yet.…”