Long non-coding RNA MMTP mediates necroptosis in alveolar macrophages during Mycoplasma hyopneumoniae infection by enhancing TNF-α transcription.

Mycoplasma hyopneumoniae (M. hyo), a major respiratory pathogen in swine, causes chronic respiratory diseases characterized by severe lung inflammation. Alveolar macrophages, which serve as the first line of defense in the respiratory immune system, undergo necroptosis in response to M. hyo infection. This form of programmed cell death amplifies pulmonary inflammation and leads to impaired lung function, yet the precise molecular mechanisms remain poorly understood. Long non-coding RNAs (lncRNAs), known for their regulatory roles in transcriptional and epigenetic processes, have been linked to various inflammatory and infectious diseases. In this study, we identified a novel lncRNA, lncRNA-MMTP, as a critical regulator of necroptosis during M. hyo infection. Mechanistically, lncRNA-MMTP interacts with the transcription factor TFII-I to enhance c-Fos promoter activity, leading to increased transcription of TNF-α and activation of the RIPK1/RIPK3/MLKL necroptotic pathway. Importantly, knockdown of lncRNA-MMTP or inhibition of TFII-I significantly reduced TNF-α levels and necroptosis in alveolar macrophages. These findings not only elucidate a new molecular pathway underlying M. hyo-induced lung inflammation but also suggest potential therapeutic targets for managing pathogen-induced inflammatory responses in the respiratory system.