The spatiotemporal distribution of cytokines orchestrates immune responses in vivo,yet the underlying mechanisms remain to be explored.We showed here that the spatial distribution of interleukin-4(IL4)in invariant nat...The spatiotemporal distribution of cytokines orchestrates immune responses in vivo,yet the underlying mechanisms remain to be explored.We showed here that the spatial distribution of interleukin-4(IL4)in invariant natural killer T(iNKT)cells regulated crosstalk between iNKT cells and dendritic cells(DCs)and controlled iNKT cell-mediated T-helper type 1(Th1)responses.The persistent polarization of IL4 induced by strong lipid antigens,that is,α-galactosylceramide(αGC),caused IL4 accumulation at the immunological synapse(IS),which promoted the activation of the IL4R-STAT6(signal transducer and activator of transcription 6)pathway and production of IL12 in DCs,which enhanced interferon-γ(IFNγ)production in iNKT cells.Conversely,the nonpolarized secretion of IL4 induced by Th2 lipid antigens with a short or unsaturated chain was incapable of enhancing this iNKT cell-DC crosstalk and thus shifted the immune response to a Th2-type response.The nonpolarized secretion of IL4 in response to Th2 lipid antigens was caused by the degradation of Cdc42 in iNKT cells.Moreover,reduced Cdc42 expression was observed in tumorinfiltrating iNKT cells,which impaired IL4 polarization and disturbed iNKT cell-DC crosstalk in tumors.展开更多
Phototropin （phot）-mediated signaling initiated by blue light （BL） plays a critical role in optimizing photosyn- thetic light capture at the plasma membrane （PM） in plants. However, the mechanisms underlying the...Phototropin （phot）-mediated signaling initiated by blue light （BL） plays a critical role in optimizing photosyn- thetic light capture at the plasma membrane （PM） in plants. However, the mechanisms underlying the regu- lation of phot activity at the PM in response to BL remain largely unclear. In this study, by single-particle tracking and stepwise photobleaching analysis of photl-GFP proteins we demonstrated that in the dark photl proteins remain in an inactive state and mostly exist as monomers. Dimerization and the diffusion rate of photl-GFP increased in a dose-dependent manner in response to BL. In contrast, BL did not affect the lateral diffusion of kinase-inactive photlD806N-GFP but did enhance its dimerization, suggesting that photl dimerization is independent of phosphorylation. Forster resonance energy transfer-fluorescence life- time imaging microscopy analysis revealed that the interaction between photl-GFP and a marker of sterol- rich lipid environments, AtRem1.3-mCherry, was enhanced with increased time of BL treatment. However, this BL-dependent interaction was not obvious in plants co-expressing phot1D806N-GFP and AtRem1.3- mCherry, indicating that BL facilitates the translocation of functional photl-GFP into AtRem1.3-1abeled microdomains to activate phot-mediated signaling. Conversely, sterol depletion attenuated photl-GFP dynamics, dimerization, and phosphorylation. Taken together, these results indicate that membrane micro- domains act as organizing platforms essential for the proper function of activated photl at the PM.展开更多
The resolution of single molecule localization imaging techniques largely depends on the precision of localization algorithms.However,the commonly used Gaussian function is not appropriate for anisotropic dipoles beca...The resolution of single molecule localization imaging techniques largely depends on the precision of localization algorithms.However,the commonly used Gaussian function is not appropriate for anisotropic dipoles because it is not the true point spread function.We derived the theoretical point spread function of tilted dipoles with restricted mobility and developed an algorithm based on an artifi cial neural network for estimating the localization,orientation and mobility of individual dipoles.Compared with fi tting-based methods,our algorithm demonstrated ultrafast speed and higher accuracy,reduced sensitivity to defocusing,strong robustness and adaptability,making it an optimal choice for both two-dimensional and threedimensional super-resolution imaging analysis.展开更多
Lipid droplets, which are conserved across almost all species, are cytoplasmic organelles used to store neutral lipids. Identification of lipid droplet regulators will be conducive to resolving obesity and other fat-a...Lipid droplets, which are conserved across almost all species, are cytoplasmic organelles used to store neutral lipids. Identification of lipid droplet regulators will be conducive to resolving obesity and other fat-associated diseases. In this paper, we selected 11 candidates that might be associated with lipid metabolism in Caenorhabditis elegans . Using a BODIPY 493/503-based flow cytometry screen, 6 negative and 3 positive regulators of fat content were identified. We selected one negative regulator of lipid content, C13C4.5 , for future study. C13C4.5 was mainly expressed in the worm intestine. We found that this gene was important for maintaining the metabolism of lipid droplets. Biochemical results revealed that 50% of triacylglycerol (TAG) was lost in C13C4.5 knockout worms. Stimulated Raman scattering (SRS) signals in C13C4.5 mutants showed only 49.6% of the fat content in the proximal intestinal region and 86.3% in the distal intestinal region compared with wild type animals. The mean values of lipid droplet size and intensity in C13C4.5 knockout animals were found to be significantly decreased compared with those in wild type worms. The LMP-1-labeled membrane structures in worm intestines were also enlarged in C13C4.5 mutant animals. Finally, fertility defects were found in C13C4.5 ( ok2087 ) mutants. Taken together, these results indicate that C13C4.5 may regulate the fertility of C. elegans by changing the size and fat content of lipid droplets by interfering with lysosomal morphology and function.展开更多
基金This work was supported by National Key R&D Program of China 2017YFA0505300the National Natural Science Foundation of China 91542203 and 81771671+1 种基金the Strategic Priority Research Program of the Chinese Academy of Sciences XDA12030208the Fundamental Research Funds for the Central Universities.
文摘The spatiotemporal distribution of cytokines orchestrates immune responses in vivo,yet the underlying mechanisms remain to be explored.We showed here that the spatial distribution of interleukin-4(IL4)in invariant natural killer T(iNKT)cells regulated crosstalk between iNKT cells and dendritic cells(DCs)and controlled iNKT cell-mediated T-helper type 1(Th1)responses.The persistent polarization of IL4 induced by strong lipid antigens,that is,α-galactosylceramide(αGC),caused IL4 accumulation at the immunological synapse(IS),which promoted the activation of the IL4R-STAT6(signal transducer and activator of transcription 6)pathway and production of IL12 in DCs,which enhanced interferon-γ(IFNγ)production in iNKT cells.Conversely,the nonpolarized secretion of IL4 induced by Th2 lipid antigens with a short or unsaturated chain was incapable of enhancing this iNKT cell-DC crosstalk and thus shifted the immune response to a Th2-type response.The nonpolarized secretion of IL4 in response to Th2 lipid antigens was caused by the degradation of Cdc42 in iNKT cells.Moreover,reduced Cdc42 expression was observed in tumorinfiltrating iNKT cells,which impaired IL4 polarization and disturbed iNKT cell-DC crosstalk in tumors.
基金This work is supported by the National Natural Science Foundation of China （31530084, 31270224） and the Program of Introducing Talents of Discipline to Universities （111 project, B13007）.
文摘Phototropin （phot）-mediated signaling initiated by blue light （BL） plays a critical role in optimizing photosyn- thetic light capture at the plasma membrane （PM） in plants. However, the mechanisms underlying the regu- lation of phot activity at the PM in response to BL remain largely unclear. In this study, by single-particle tracking and stepwise photobleaching analysis of photl-GFP proteins we demonstrated that in the dark photl proteins remain in an inactive state and mostly exist as monomers. Dimerization and the diffusion rate of photl-GFP increased in a dose-dependent manner in response to BL. In contrast, BL did not affect the lateral diffusion of kinase-inactive photlD806N-GFP but did enhance its dimerization, suggesting that photl dimerization is independent of phosphorylation. Forster resonance energy transfer-fluorescence life- time imaging microscopy analysis revealed that the interaction between photl-GFP and a marker of sterol- rich lipid environments, AtRem1.3-mCherry, was enhanced with increased time of BL treatment. However, this BL-dependent interaction was not obvious in plants co-expressing phot1D806N-GFP and AtRem1.3- mCherry, indicating that BL facilitates the translocation of functional photl-GFP into AtRem1.3-1abeled microdomains to activate phot-mediated signaling. Conversely, sterol depletion attenuated photl-GFP dynamics, dimerization, and phosphorylation. Taken together, these results indicate that membrane micro- domains act as organizing platforms essential for the proper function of activated photl at the PM.
基金We thank L.L.Looger(Janelia Farm Research Campus)for providing the mEos2 cDNA and Toshio Yanagida(Osaka University,Japan)for sharing the Q rods.This work was supported by grants from the National Basic Research Program(973 Program)(Nos.2010CB833701 and 2010CB912303)the National Key Technology R&D Program(SQ2011SF11B01041)+2 种基金the National Natural Science Foundation of China(Grant Nos.31130065,31170818,90913022,31127901,and 31100615)the Beijing Natural Science Foundation(7121008)the Chinese Academy of Sciences Project(KSCX1-1W-J-3,KSCX2-EWQ-11,and 2009-154-27).
文摘The resolution of single molecule localization imaging techniques largely depends on the precision of localization algorithms.However,the commonly used Gaussian function is not appropriate for anisotropic dipoles because it is not the true point spread function.We derived the theoretical point spread function of tilted dipoles with restricted mobility and developed an algorithm based on an artifi cial neural network for estimating the localization,orientation and mobility of individual dipoles.Compared with fi tting-based methods,our algorithm demonstrated ultrafast speed and higher accuracy,reduced sensitivity to defocusing,strong robustness and adaptability,making it an optimal choice for both two-dimensional and threedimensional super-resolution imaging analysis.
基金support from the National Basic Research Program(973 Program)(Nos.2013CB910103 and 2010CB912303)the National Natural Science Foundation of China(Grant Nos.31170818 and 31270910)the project from the Chinese Academy of Sciences(KSCX2-EW-Q-11).
文摘Lipid droplets, which are conserved across almost all species, are cytoplasmic organelles used to store neutral lipids. Identification of lipid droplet regulators will be conducive to resolving obesity and other fat-associated diseases. In this paper, we selected 11 candidates that might be associated with lipid metabolism in Caenorhabditis elegans . Using a BODIPY 493/503-based flow cytometry screen, 6 negative and 3 positive regulators of fat content were identified. We selected one negative regulator of lipid content, C13C4.5 , for future study. C13C4.5 was mainly expressed in the worm intestine. We found that this gene was important for maintaining the metabolism of lipid droplets. Biochemical results revealed that 50% of triacylglycerol (TAG) was lost in C13C4.5 knockout worms. Stimulated Raman scattering (SRS) signals in C13C4.5 mutants showed only 49.6% of the fat content in the proximal intestinal region and 86.3% in the distal intestinal region compared with wild type animals. The mean values of lipid droplet size and intensity in C13C4.5 knockout animals were found to be significantly decreased compared with those in wild type worms. The LMP-1-labeled membrane structures in worm intestines were also enlarged in C13C4.5 mutant animals. Finally, fertility defects were found in C13C4.5 ( ok2087 ) mutants. Taken together, these results indicate that C13C4.5 may regulate the fertility of C. elegans by changing the size and fat content of lipid droplets by interfering with lysosomal morphology and function.
