Long noncoding RNA MALAT1 modulates sepsis-induced cardiac inflammation through the miR-150-5p/NF-κB axis

Accumulating evidence shows that long noncoding RNAs (lncRNAs) and microRNAs (miRNAs) are involved in the sepsis inflammatory response. However, the involvement of lncRNA metastasis-associated lung adenocarcinoma transcript 1 (MALAT1)/miR-150-5p axis in sepsis has not been reported.

We first demonstrated that MALAT1 depletion is responsible for the sepsis inflammatory response by inhibiting the expressions of IL-6 and TNF-α and the NF-κB signaling pathway by upregulating miR-150-5p.

Lipopolysaccharide (LPS)-treated H9c2 cells were used to establish a sepsis cell model in vitro. The expressions of MALAT1 and miR-150-5p were monitored using a quantitative reverse transcription polymerase chain reaction (qRT-PCR). An ELISA assay was perfor med to detect the levels of interleukin-6 (IL-6) and tumor necrosis factor-α (TNF-α). The protein expression of NF-κB was determined by western blot. A luciferase reporter assay was introduced to verify the relationship between MALAT1/miR-150-5p. An RNA immunoprecipitation (RIP) assay and an RNA pull-down assay were carried out to detect the abundance of MALAT1.

MALAT1 was highly expressed, but miR-150-5p was downregulated in LPS-mediated H9c2 cells. Meanwhile, LPS significantly promoted the expressions of IL-6, TNF-α, and NF-κB. MALAT1 depletion attenuated the effect of LPS on the expressions of the inflammatory factors and the NF-κB signaling pathway, which was consistent with that of miR-150-5p overexpression. MALAT1 interacted with miR-150-5p. In addition, the rescue-of-function experiments also indicated that the loss of miR-150-5p undermined the effect of MALAT1 downregulation on H9c2 cells with LPS treatment.