Long non-coding RNA X-inactive specific transcript silencing ameliorates primary graft dysfunction following lung...

Area of Science:

• Immunology
• Molecular Biology
• Transplantation Science

Background:

• Primary graft dysfunction (PGD) is a leading cause of mortality following lung transplantation, representing a form of acute lung injury (ALI).
• The precise molecular mechanisms underlying PGD, particularly the role of long non-coding RNAs (lncRNAs) and their interactions with microRNAs (miRNAs), remain largely unelucidated.
• This study investigates the specific role of the lncRNA X-inactive specific transcript (XIST) in the pathogenesis of PGD.

Purpose of the Study:

• To elucidate the mechanism by which lncRNA XIST contributes to PGD after lung transplantation.
• To investigate the regulatory relationship between XIST, miR-21, and IL-12A in the context of PGD.
• To assess the therapeutic potential of targeting XIST and neutrophil extracellular trap (NET) formation in PGD.

Main Methods:

• Quantitative real-time PCR (RT-qPCR) and western blot analysis were used to measure the expression of miR-21, IL-12A, and XIST.
• Dual luciferase reporter, RNA pull-down, and RNA immunoprecipitation (RIP) assays were employed to confirm targeting and binding interactions.
• In vivo and in vitro loss- and gain-of-function studies were performed in a rat model of prolonged cold ischemia and using polymorphonuclear neutrophils (PMNs).

Main Results:

• In PGD patients, miR-21 expression was decreased, while XIST and IL-12A expression were elevated in bronchoalveolar lavage fluid.
• Overexpression of miR-21 in rats and PMNs reduced pro-inflammatory factors, decreased chemokines, and promoted PMN apoptosis.
• XIST was confirmed to upregulate IL-12A in a miR-21-dependent manner, and XIST silencing reduced NET formation and enhanced PMN apoptosis by modulating miR-21 and IL-12A levels.

Conclusions:

• lncRNA XIST promotes PGD post-lung transplantation by upregulating IL-12A through interaction with miR-21, leading to NET formation.
• These findings highlight a novel molecular pathway implicated in PGD pathogenesis.
• Targeting XIST and inhibiting NET formation presents a potential therapeutic strategy for managing PGD.