Monkeypox,a zoonotic disease caused by the monkeypox virus(MPXV),has significant global public health implications.Inflammasomes serve as crucial components of the innate immune system,detecting pathogens and triggeri...Monkeypox,a zoonotic disease caused by the monkeypox virus(MPXV),has significant global public health implications.Inflammasomes serve as crucial components of the innate immune system,detecting pathogens and triggering cell death in infected cells to eliminate harmful agents.However,the precise molecular mechanisms governing the activation of inflammasomes during MPXV infection remain largely unclear.Using CRISPR-knockout cytosolic innate immune sensor screening,we identified AIM2 as the sensor for MPXV within the inflammasome,a trigger for inflammatory cell death.Mechanistically,AIM2 forms a complex with essential cell death molecules,including ASC and caspase-1(CASP1),without interacting with RIPK3 or CASP8.Loss of ASC,CASP1,or gasdermin D(GSDMD)reduced cell death following MPXV infection,whereas loss of GSDME,CASP3,CASP6,CASP7,CASP9,RIPK3,or MLKL did not.Pyroptotic cell death was predominantly observed in infected cells,whereas apoptotic and necroptotic signaling pathways were primarily activated in uninfected bystander cells.Furthermore,we found that the transcription factor IRF1 serves as an upstream regulator of AIM2,controlling AIM2-dependent cell death.In experiments involving AIM2-deficient mice infected with MPXV,we observed a decrease in proinflammatory cytokines,multiple inflammatory cell death pathways,and leukocyte migration,culminating in increased viral spread.CAST/EiJ mice succumbed to high-dose MPXV infection within 8 days,whereas AIM2 inhibition increased survival,with 10%of the mice treated with an AIM2 inhibitor surviving the infection.In a low-dose infection model,AIM2 inhibition reduced IL-1βand IL-18 production,LDH release,and tissue pathology.These findings highlight the critical role of AIM2-mediated inflammasome activation,along with multiple programmed cell death pathways,in shaping the innate immune response to MPXV infection,offering valuable insights for developing therapeutic strategies targeting AIM2 and the broader innate immune response against monkeypox.展开更多
In order to flower in the appropriate season,plants monitor light and temperature changes and alter downstream pathways that regulate florigen genes such as Arabidopsis(Arabidopsis thaliana)FLOWERING LOCUS T(FT).In Ar...In order to flower in the appropriate season,plants monitor light and temperature changes and alter downstream pathways that regulate florigen genes such as Arabidopsis(Arabidopsis thaliana)FLOWERING LOCUS T(FT).In Arabidopsis,FT messenger RNA levels peak in the morning and evening under natural long-day conditions(LDs).However,the regulatory mechanisms governing morning FT induction remain poorly understood.The morning FT peak is absent in typical laboratory LDs characterized by high red:far-red light(R:FR)ratios and constant temperatures.Here,we demonstrate that ZEITLUPE(ZTL)interacts with the FT repressors TARGET OF EATs(TOEs),thereby repressing morning FT expression in natural environments.Under LDs with simulated sunlight(R:FR=1.0)and daily temperature cycles,which are natural LD-mimicking environmental conditions,FT transcript levels in the ztl mutant were high specifically in the morning,a pattern that was mirrored in the toe1 toe2 double mutant.Low night-to-morning temperatures increased the inhibitory effect of ZTL on morning FT expression by increasing ZTL protein levels early in the morning.Far-red light counteracted ZTL activity by decreasing its abundance(possibly via phytochrome A(phyA))while increasing GIGANTEA(GI)levels and negatively affecting the formation of the ZTL-GI complex in the morning.Therefore,the phyA-mediated high-irradiance response and GI play pivotal roles in morning FT induction.Our findings suggest that the delicate balance between low temperature-mediated ZTL activity and the far-red light-mediated functions of phyA and GI offers plants flexibility in fine-tuning their flowering time by controlling FT expression in the morning.展开更多
文摘Monkeypox,a zoonotic disease caused by the monkeypox virus(MPXV),has significant global public health implications.Inflammasomes serve as crucial components of the innate immune system,detecting pathogens and triggering cell death in infected cells to eliminate harmful agents.However,the precise molecular mechanisms governing the activation of inflammasomes during MPXV infection remain largely unclear.Using CRISPR-knockout cytosolic innate immune sensor screening,we identified AIM2 as the sensor for MPXV within the inflammasome,a trigger for inflammatory cell death.Mechanistically,AIM2 forms a complex with essential cell death molecules,including ASC and caspase-1(CASP1),without interacting with RIPK3 or CASP8.Loss of ASC,CASP1,or gasdermin D(GSDMD)reduced cell death following MPXV infection,whereas loss of GSDME,CASP3,CASP6,CASP7,CASP9,RIPK3,or MLKL did not.Pyroptotic cell death was predominantly observed in infected cells,whereas apoptotic and necroptotic signaling pathways were primarily activated in uninfected bystander cells.Furthermore,we found that the transcription factor IRF1 serves as an upstream regulator of AIM2,controlling AIM2-dependent cell death.In experiments involving AIM2-deficient mice infected with MPXV,we observed a decrease in proinflammatory cytokines,multiple inflammatory cell death pathways,and leukocyte migration,culminating in increased viral spread.CAST/EiJ mice succumbed to high-dose MPXV infection within 8 days,whereas AIM2 inhibition increased survival,with 10%of the mice treated with an AIM2 inhibitor surviving the infection.In a low-dose infection model,AIM2 inhibition reduced IL-1βand IL-18 production,LDH release,and tissue pathology.These findings highlight the critical role of AIM2-mediated inflammasome activation,along with multiple programmed cell death pathways,in shaping the innate immune response to MPXV infection,offering valuable insights for developing therapeutic strategies targeting AIM2 and the broader innate immune response against monkeypox.
基金supported by the Japan Society for the Promotion of Science(JSPS)KAKENHI grant(No.19K16170 and No.23K05817 to A.K.)National Institutes of Health(NIH)(No.R01GM079712 to T.I.)the National Research Foundation(NRF)of Korea grant funded by the Korean Government(MSIT)(No.NRF-2020R1A2C1014655 andNo.NRF-2021R1A4A1032888 to Y.H.S.).
文摘In order to flower in the appropriate season,plants monitor light and temperature changes and alter downstream pathways that regulate florigen genes such as Arabidopsis(Arabidopsis thaliana)FLOWERING LOCUS T(FT).In Arabidopsis,FT messenger RNA levels peak in the morning and evening under natural long-day conditions(LDs).However,the regulatory mechanisms governing morning FT induction remain poorly understood.The morning FT peak is absent in typical laboratory LDs characterized by high red:far-red light(R:FR)ratios and constant temperatures.Here,we demonstrate that ZEITLUPE(ZTL)interacts with the FT repressors TARGET OF EATs(TOEs),thereby repressing morning FT expression in natural environments.Under LDs with simulated sunlight(R:FR=1.0)and daily temperature cycles,which are natural LD-mimicking environmental conditions,FT transcript levels in the ztl mutant were high specifically in the morning,a pattern that was mirrored in the toe1 toe2 double mutant.Low night-to-morning temperatures increased the inhibitory effect of ZTL on morning FT expression by increasing ZTL protein levels early in the morning.Far-red light counteracted ZTL activity by decreasing its abundance(possibly via phytochrome A(phyA))while increasing GIGANTEA(GI)levels and negatively affecting the formation of the ZTL-GI complex in the morning.Therefore,the phyA-mediated high-irradiance response and GI play pivotal roles in morning FT induction.Our findings suggest that the delicate balance between low temperature-mediated ZTL activity and the far-red light-mediated functions of phyA and GI offers plants flexibility in fine-tuning their flowering time by controlling FT expression in the morning.
