Diazepam inhibited lipopolysaccharide (LPS)-induced pyroptotic cell death and alleviated pulmonary fibrosis in mice by specifically activating GABAA receptor α4-subunit

Diazepam could regulate immune system and inflammation, which might be a potential therapeutic agent for pulmonary fibrosis in clinic. This study showed that diazepam reversed LPS-induced inhibition of cell proliferation and promotion of cell apoptosis. Of note, LPS specifically induced Caspase-11 dependent cell pyroptosis, which were significantly attenuated by diazepam or pyroptosis inhibitor necrosulfonamide (NSA) treatment. In addition, α4- and α5-subunits of GABA_ARs were highly expressed in human bronchial 16HBE cells, human pulmonary epithelial cells (BEAS-2B) and pulmonary epithelial cells isolated from mice (mPECs). Further results showed that only knock-down of α4-GABA_ARs abrogated the effects of diazepam on LPS induced cell pyroptosis, apoptosis and proliferation. Similiarly, either diazepam or NSA treatment could alleviate development of LPS induced inflammatory reactions and pulmonary fibrosis in mice, which were abrogated by synergistically knocking down α4-GABA_ARs. Taken together, diazepam alleviated LPS-induced cell pyroptosis and development of pulmonary fibrosis in mice by activating α4-GABA_ARs.