MTOR (mechanistic target of rapamycin) plays a crucial role in many major cellular processes and a growing number of proliferative and metabolic diseases. In a study, Prof. Huahao Shen’s group observed that lipopolysaccharide (LPS) stimulation induced MTOR phosphorylation and decreased the expression of MAP1LC3B/LC3B (microtubule-associated protein 1 light chain 3beta)-II in mouse lung epithelium and in human bronchial epithelial (HBE) cells. The activation of MTOR in HBE cells was mediated by TLR4 (toll-like receptor 4) signaling. Genetic knockdown of MTOR or overexpression of autophagy-related proteins significantly attenuated, whereas inhibition of autophagy further augmented, LPS-induced expression of IL6 (interleukin 6) and IL8, through NFKB signaling in HBE cells. Mice with specific knockdown of Mtor in bronchial or alveolar epithelial cells exhibited significantly attenuated airway inflammation, barrier disruption, and lung edema, and displayed prolonged survival in response to LPS exposure. Taken together, their results demonstrate that activation of MTOR in the epithelium promotes LPS-induced ALI, likely through downregulation of autophagy and the subsequent activation of NFKB. Thus, inhibition of MTOR in pulmonary epithelial cells may represent a novel therapeutic strategy for preventing ALI induced by certain bacteria. Their finding was published in Autophagy.
