摘要: The keystone pathogen Porphyromonas gingivalis (P.g.) is responsible for cementum resorption in periodontitis; however, the mechanism involved in it remains unclear. Sirtuin 3 (Sirt3) is a NAD(+)-dependent protein deacetylase contributing to mitochondrial homeostasis and various cell functions. In this study, the expression of Sirt3 in cementoblasts was found to be increased during cementoblast mineralisation and cementum development, while it decreased gradually under P.g. infection in a multiplicity of infection-dependent manner. Compared with wild type mice, the Sirt3 knockout mice showed less cellular cementum and lower mineralisation capacity with decreased expression of Runx2 and OCN in cementoblasts. Sirt3 inhibition by 3-TYP or Sirt3 silencing by lentivirus infection both confirmed the impaired cementogenesis. Conversely, honokiol (HKL) was simulated to bind Sirt3 and was applied to activate Sirt3 in cementoblasts. HKL-mediated Sirt3 activation facilitated cementoblast mineralisation and rescued P.g.-suppressed cementoblast mineralisation markedly. Superoxide dismutase 2 (SOD2), the downstream molecule of Sirt3, showed a similar expression pattern to Sirt3 under different conditions. Silencing of SOD2 was demonstrated to restrain cementoblast mineralisation. The pan acetylation was detected to decrease under Sirt3-upregulating conditions and increase under Sirt3-downregulating conditions. The binding of Sirt3 and SOD2 in cementoblasts was also verified. Furthermore, SOD2 acetylation and specific SOD2-K68 acetylation were found to be upregulated under P.g. or Sirt3 silencing conditions and downregulated by HKL stimulation. Moreover, K68Q mutation simulating acetylation decreased cementoblast mineralisation, while K68R mutation simulating deacetylation increased it. Altogether, Sirt3 deacetylates SOD2 via K68 to orchestrate P.g.-perturbed cementogenesis, and HKL is a Sirt3-targeted treatment candidate.

摘要: As crucial phagocytes of the innate immune system, macrophages (M phi s) protect mammalian hosts, maintain tissue homeostasis and influence disease pathogenesis. Nonetheless, M phi s are susceptible to various pathogens, including bacteria, viruses and parasites, which cause various infectious diseases, necessitating a deeper understanding of pathogen-M phi interactions and therapeutic insights. Pluripotent stem cells (PSCs) have been efficiently differentiated into PSC-derived M phi s (PSCdM phi s) resembling primary M phi s, advancing the modelling and cell therapy of infectious diseases. However, the mass production of PSCdM phi s, which lack proliferative capacity, relies on large-scale expansions of PSCs, thereby increasing both costs and culture cycles. Notably, M phi s deficient in the MafB/c-Maf genes have been reported to re-enter the cell cycle with the stimulation of specific growth factor cocktails, turning into self-renewing M phi s (SRM phi s). This review summarizes the applications of PSCdM phi s in the modelling and cell therapy of infectious diseases and strategies for establishing SRM phi s. Most importantly, we innovatively propose that PSCs can serve as a gene editing platform to creating PSC-derived SRM phi s (termed PSRM phi s), addressing the resistance of M phi s against genetic manipulation. We discuss the challenges and possible solutions in creating PSRM phi s. In conclusion, this review provides novel insights into the development of physiologically relevant and expandable M phi models, highlighting the enormous potential of PSRM phi s as a promising avenue for the modelling and cell therapy of infectious diseases.

摘要: Microglia, considered as the main immune responder, play an important role in regulating neuroinflammation in central nervous system (CNS) disorders. Our previous work found that TREM2 is highly expressed in microglia and is related to their functional state. However, the specific role of TREM2 in spinal cord injury has not yet been explored. To further investigate the potential mechanism of TREM2, we performed single-cell sequencing on wild-type (Wt) and Trem2-/- mice before and after spinal cord injury. Compared to Wt mice, the lysosome, autophagy and membrane-related pathways are more strongly activated in Trem2-/- mice, suggesting that TREM2 may exert its effects by influencing lysosomal membranes and autophagy. Mechanistically, we demonstrated that the knockout of Trem2 can reduce the nuclear translocation of TFEB by decreasing the phosphorylation of Syk. Furthermore, we validated that in vitro and in vivo silencing Trem2 can promote autophagy by repairing lysosomal membrane permeabilization. Through immunofluorescence, 3D gait analysis, motor evoked potential experiments, H&E staining and Masson staining, we demonstrated that the increased level of autophagy can rescue more microglia in vivo and promote both functional and histological recovery of spinal cord injury. Collectively, these results not only suggest that microglial lysosomal autophagy is regulated in a TREM2-dependent LMP manner, but also, more importantly, they provide a promising clinical translation strategy based on gene therapy for lysosome-related central nervous system disorders.