TSPO deficiency exacerbates acute lung injury via NLRP3 inflammasome-mediated pyroptosis

Background:Acute respiratory distress syndrome(ARDS)is a common cause of respiratory failure in many critically ill patients.Although inflammasome activation plays an important role in the induction of acute lung injury(ALI)and ARDS,the regulatory mechanism of this process is still unclear.When cells are stimulated by inflammation,the integrity and physiological function of mitochondria play a crucial part in pyroptosis.However,the underlying mechanisms and function of mitochondrial proteins in the process of pyroptosis are largely not yet known.Here,we identified the 18-kDa translocator protein(TSPO),a mitochondrial outer membrane protein,as an important mediator regulating nucleotide-binding domain,leucine-rich repeat,and pyrin domain-containing protein 3(NLRP3)inflammasome activation in macrophages during ALI.Methods:TSPO gene knockout(KO)and lipopolysaccharide(LPS)-induced ALI/ARDS mouse models were employed to investigate the biological role of TSPO in the pathogenesis of ARDS.Murine macrophages were used to further characterize the effect of TSPO on the NLRP3 inflammasome pathway.Activation of NLRP3 inflammasome was preformed through LPS+adenosine triphosphate(ATP)co-stimulation,followed by detection of mitochondrial membrane potential,reactive oxygen species(ROS)production,and cell death to evaluate the potential biological function of TSPO.Comparisons between two groups were performed with a two-sided unpaired t-test.Results:TSPO-KO mice exhibited more severe pulmonary inflammation in response to LPS-induced ALI.TSPO deficiency resulted in enhanced activation of the NLRP3 inflammasome pathway,promoting more proinflammatory cytokine production of macrophages in LPS-injured lung tissue,including interleukin(IL)-1β,IL-18,and macrophage inflammatory protein(MIP)-2.Mitochondria in TSPO-KO macrophages tended to depolarize in response to cellular stress.The increased production of mitochondrial damage-associated molecular pattern led to enhanced mitochondrial membrane depolarization and pyroptosis in TSPO-KO cells.Conclusion:TSPO may be the key regulator of cellular pyroptosis,and it plays a vital protective role in ARDS occurrence and development.

Anti-PD-1 antibody armored γδ T cells enhance anti-tumor efficacy in ovarian cancer

γδ T cells have the unique ability to detect a wide range of tumors with low mutation burdens,making them attractive candidates for CAR-T-cell therapy.Unlike aβT cells and other immune cells,γδ T cells are superior in MHC non-restriction,selective cell recruitment,and rapid activation.However,clinical trials have shown limited clinical benefits,and the adoptive transplantation of γδ T cells has often fallen short of expectations.We hypothesized that the limited effectiveness of γδ T cells in eradicating tumor cells may be attributed to the inhibitory tumor microenvironment induced by the suppressive PD-1/PD-L1 axis.Herein,we constructed novel armored γδ T cells capable of secreting humanized anti-PD-1 antibodies,referred to as"Lv-PD1-ys T cells.Lv-PD1-γδ T cells showed improved proliferation and enhanced cytotoxicity against tumor cells,resulting in augmented therapeutic effects and survival benefits in ovarian tumor-bearing mice.These engineered cells demonstrated a prolonged in vivo survival of more than 29 days,without any potential for tumorigenicity in immunodeficient NOD/SCID/null mice.We also found that Lv-PD1-γδ T cells exhibited excellent tolerance and safety in humanized NOD/SCID/null mice.With attenuated or eliminated immunosuppression and maximized cytotoxicity efficacy by the local secretion of anti-PD1 antibodies in tumors,Lv-PD1-γδ T cells can serve as a promising"off-the-shelf"cell therapy against cancers.