The Role Of Inflammasome-associated Proteins In The Development Of Neuroinflammation And Neurodegenerative Diseases

Obejectives: Studies have shown that inflammasomes,especially NLRP3,play an important role in multiple sclerosis(MS).However,the effects of Gasdermin D(GSDMD),a newly identified pyroptosis executioner downstream of NLRP3 inflammasome,in MS has not been well defined.This study aimed to explore the important role and potential mechanism of GSDMD in MS and provide clues for clinical treatments of MS.Methods: We firstly established an experimental allergic encephalomyelitis(EAE)mouse model and detected the expression of GSDMD on EAE peak stage.We compaired the phenotypes between the wiledtype and GSDMD knockout mice in EAE model,including clinical scoring,pathophysiological feature,and immune cells infiltration in CNS.Bone marrow chimeras and cell-specific conditional-knockout mice were further used to explore the major working cells of GSDMD.RNA-seq analysis were performed on the indicated cells to investigate the genetic regulatory pathways underlying GSDMD function in EAE.And the role and regulatory mechanism of GSDMD in EAE was further investigated by T-cell adoptive transfer and cytokine rescue experiments.Results: Here,we observed that the levels of GSDMD protein was greatly enhanced in the CNS of EAE mice,especially near the areas surrounding blood vessels,accompanied with immune cells infiltration.The development of EAE in GSDMD knockout mice was suppressed compaired to wiledtype mice.Recipient mice receiving GSDMD knockout mice bone marrow cells had much milder pathogenesis of EAE in bone marrow transplantation experiments.While the specifically deletion of GSDMD in T-cell and microglia had no effect on the onset of EAE.We also observed that GSDMD knockout mice showed a size increasement,accumulation of CD4+ T cells and decrease of Th1/17 cells proportion in the secondary lymphoid organs at the peak of EAE.The RNA-seq analysis revealed the expression of various T-cell response relative genes was significantly downregulated in GSDMD knockout mice.Adoptive transfer experiments showed the effect of T cells of GSDMD knockout mice on the induction of EAE in recipient mice was decreased.Myeloid cells specific deficiency of GSDMD inhibited the induction of EAE and attenuated T-cell proliferation.The administration of inflammasome-related cytokines partially rescued the impairment of pathogenesis of EAE in GSDMD knockout mice.Conclusion: In summary,peripheral myeloid cell-intrinsic GSDMD mediates pyroptosis to instigate inflammation and promote the activation and differentiation of T cell in the secondary lymphoid organs,thereby driving T cellmediated neuroinflammation and demyelination in the CNS of EAE.The development of therapeutic strategies to specifically target GSDMD-mediated pyroptosis might be useful for the inhibition of CNS inflammation and MS treatment.Objective: Studies have shown that inflammasomes play an important role in a variety of neurodegenerative diseases.However,the effect of AIM2 in Parkinson's disease(PD),as well as its regulation of neuroinflammation during disease,has not been reported.The aim of this study was to clarify the role that AIM2 may play in the development of MPTP-induced acute PD mice model,and to provide new clues for clinical treatment of PD and neuroinflammation.Methods: We firstly tested the PDlike behavior and motor disorder in wild-type and AIM2 knockout mice in MPTP-induced acute PD model by open field test,accelerating rotarod test and pole test.Then,the loss of dopaminergic neurons in the substantia nigra region of wiled-type mice and knockout mice was analyzed.And the activation of glial cells in the substantia nigra region was examined as well.The gene expresssion of proinflammatory cytokines was analysis by q PCR.At last,conditional specific knockout mice were used to explore the influence of AIM2 deficiency in microglia on the development of MPTP-induced PD.Results: We found that AIM2 knockout mice showed more severe PD-like behavior and motor dysfunction than wild-type mice after MPTP induction,accompanied with a higher proportion of dopamine neuron cell loss in the substantia nigra region.Microglia and astrocyte activation were also more severe in AIM2 knockout mice.q PCR results showed that AIM2 deletion up-regulated the expression of a series of proinflammatory genes.In addition,AIM2 deficiency in microglia also contributed to the MPTP-induced PD development.Conclusion: AIM2 plays a neuroprotective role on MPTP-induced acute PD mice model.And AIM2 deletion can up-regulate proinflammatory cytokines,aggravate glial cells activation and promote the development of PD.