MicroRNA-26b-5p promotes development of neonatal respiratory distress syndrome by inhibiting differentiation of mesenchymal stem cells to type II of alveolar epithelial cells via regulating Wnt5a.

OBJECTIVE

The aim was to investigate the role of microRNA-26b-5p in regulating mesenchymal stem cells (MSCs) differentiation to type II of alveolar epithelial cells (AECII) in the disease course of neonatal respiratory distress syndrome (NRDS).

MATERIALS AND METHODS

MSCs were first derived from rat bone marrow. In vitro induction of MSCs differentiation to AECII was conducted by SAGM. The mRNA levels of microRNA-26b-5p, Wnt5a, and AECII-related genes (Occludin, KGF, CK18, SpA, SpB, and SpC) during the process of cell differentiation were detected by quantitative Real Time-Polymerase Chain Reaction (qRT-PCR). Enzyme-linked immunosorbent assay (ELISA) was conducted for detecting levels of inflammatory factors tumor necrosis factor-α (TNF-α), interferon-α (INF-α), and interleukin-1 (IL-1) in cell supernatant. Dual-luciferase reporter gene assay was then carried out to verify the regulatory effect of microRNA-26b-5p on Wnt5a. MicroRNA-26b-5p expression in serum samples of NRDS neonates and healthy neonates was detected by qRT-PCR as well.

RESULTS

MicroRNA-26b-5p was overexpressed in NRDS neonates than those of healthy neonates. Besides, microRNA-26b-5p was highly expressed in the process of MSCs differentiation to AECII. MicroRNA-26b-5p overexpression remarkably inhibited AECII differentiation and Wnt5a expression. Levels of TNF-α, INF-α, and IL-1 in cell supernatant during differentiation induction were elevated. The regulatory effects of microRNA-26b-5p on AECII differentiation, Wnt5a expression, and inflammatory response were reversed by Wnt5a overexpression.

CONCLUSIONS

MicroRNA-26b-5p inhibits MSCs differentiation to AECII via inhibiting Wnt5a expression through the Wnt pathway.