Accurate prediction and monitoring of acute graft-versus-host disease(aGVHD)remain challenging in allogeneic hematopoietic stem cell transplantation(allo-HSCT)as current diagnostic approaches rely on symptomatic prese...Accurate prediction and monitoring of acute graft-versus-host disease(aGVHD)remain challenging in allogeneic hematopoietic stem cell transplantation(allo-HSCT)as current diagnostic approaches rely on symptomatic presentation.Therefore,this study sought to identify predictive biomarkers and therapeutic targets for aGVHD through longitudinal immune monitoring and mechanistic investigations.In this study,peripheral blood samples were collected weekly for 100 days from a group of 115 allo-HSCT recipients.CD38^(+)HLA-DR^(+)CD8^(+)T(activated CD8^(+)T)cells were analyzed using the t-distributed stochastic neighbor embedding(t-SNE)algorithm for high-dimensional data visualization and population identification.Clinical data integration was used to assess biomarker utility.Mechanistic studies included interleukin-15(IL-15)stimulation,signaling pathway inhibition,cytotoxicity assays,and xenogeneic GVHD modeling with anti-CD38(daratumumab)intervention.Our results revealed that sustained elevation of activated CD8^(+)T cells(>36.6%)within the first month post-transplantation predicted aGVHD onset with high accuracy(AUC=0.84,P<0.001).Cell frequency dynamically correlated with treatment outcome,decreasing substantially in responders.Mechanistically,IL-15 drove T-cell receptor(TCR)-independent cytotoxicity via PI3K/mTOR activation,mediated by natural killer group 2D(NKG2D)and major histocompatibility complex class I chain related proteins A(MIC-α)interactions,validated by reduced K562 cell lysis following antibody blockade.In an 8-10-week-old NSG mouse model for xenogeneic transplantation,treatment with daratumumab(5 mg/kg)effectively lowered histopathological damage and increased survival.In conclusion,activated CD8+T cells can serve as dual-purpose biomarkers for early aGVHD prediction and treatment monitoring.Their IL-15-driven cytotoxicity represents a targetable pathway,with daratumumab demonstrating therapeutic efficacy.展开更多
The concept advanced by Berridge and colleagues that intracellular Ca2+-stores can be mobilized in an agonist-dependent and messenger(IP3)-mediated manner has put Ca 2+-mobilization at the center stage of signal trans...The concept advanced by Berridge and colleagues that intracellular Ca2+-stores can be mobilized in an agonist-dependent and messenger(IP3)-mediated manner has put Ca 2+-mobilization at the center stage of signal transduction mechanisms.During the late 1980s,we showed that Ca2+-stores can be mobilized by two other messengers unrelated to inositol trisphosphate(IP 3) and identified them as cyclic ADP-ribose(cADPR),a novel cyclic nucleotide from NAD,and nicotinic acid adenine dinucleotide phosphate(NAADP),a linear metabolite of NADP.Their messenger functions have now been documented in a wide range of systems spanning three biological kingdoms.Accumulated evidence indicates that the target of cADPR is the ryanodine receptor in the sarco/endoplasmic reticulum,while that of NAADP is the two pore channel in endolysosomes. As cADPR and NAADP are structurally and functionally distinct,it is remarkable that they are synthesized by the same enzyme.They are thus fraternal twin messengers.We first identified the Aplysia ADP-ribosyl cyclase as one such enzyme and,through homology,found its mammalian homolog,CD38.Gene knockout in mice confirms the important roles of CD38 in diverse physiological functions from insulin secretion,susceptibility to bacterial infection,to social behavior of mice through modulating neuronal oxytocin secretion.We have elucidated the catalytic mechanisms of the Aplysia cyclase and CD38 to atomic resolution by crystallography and site-directed mutagenesis.This article gives a historical account of the cADPR/NAADP/CD38-signaling pathway and describes current efforts in elucidating the structure and function of its components.展开更多
基金the National Key Research and Development Program of China(grant number 2024YFC2510502 to W.S.)the National Natural Science Foundation of China(grant number 8217060280 to L.Y.)+2 种基金the Natural Science Foundation of Guang dong Province(grant number 2114050002084 to L.Y.)the Innovative Clinical Technique of Guangzhou(grant number 2023CGX01 to W.S.)the Science and Technology Key Project of Guangzhou(grant numbers 02102010037 to W.S.,SL2024A03J01319,SL2024A04J00240 to L.Y.).
文摘Accurate prediction and monitoring of acute graft-versus-host disease(aGVHD)remain challenging in allogeneic hematopoietic stem cell transplantation(allo-HSCT)as current diagnostic approaches rely on symptomatic presentation.Therefore,this study sought to identify predictive biomarkers and therapeutic targets for aGVHD through longitudinal immune monitoring and mechanistic investigations.In this study,peripheral blood samples were collected weekly for 100 days from a group of 115 allo-HSCT recipients.CD38^(+)HLA-DR^(+)CD8^(+)T(activated CD8^(+)T)cells were analyzed using the t-distributed stochastic neighbor embedding(t-SNE)algorithm for high-dimensional data visualization and population identification.Clinical data integration was used to assess biomarker utility.Mechanistic studies included interleukin-15(IL-15)stimulation,signaling pathway inhibition,cytotoxicity assays,and xenogeneic GVHD modeling with anti-CD38(daratumumab)intervention.Our results revealed that sustained elevation of activated CD8^(+)T cells(>36.6%)within the first month post-transplantation predicted aGVHD onset with high accuracy(AUC=0.84,P<0.001).Cell frequency dynamically correlated with treatment outcome,decreasing substantially in responders.Mechanistically,IL-15 drove T-cell receptor(TCR)-independent cytotoxicity via PI3K/mTOR activation,mediated by natural killer group 2D(NKG2D)and major histocompatibility complex class I chain related proteins A(MIC-α)interactions,validated by reduced K562 cell lysis following antibody blockade.In an 8-10-week-old NSG mouse model for xenogeneic transplantation,treatment with daratumumab(5 mg/kg)effectively lowered histopathological damage and increased survival.In conclusion,activated CD8+T cells can serve as dual-purpose biomarkers for early aGVHD prediction and treatment monitoring.Their IL-15-driven cytotoxicity represents a targetable pathway,with daratumumab demonstrating therapeutic efficacy.
基金supported by the Research Grants Council of Hong Kong(Grant Nos.769107,768408, 769309 and 770610)the National Natural Science Foundation of China/the Research Grants Council of Hong Kong(Grant No.N_HKU 722/08)
文摘The concept advanced by Berridge and colleagues that intracellular Ca2+-stores can be mobilized in an agonist-dependent and messenger(IP3)-mediated manner has put Ca 2+-mobilization at the center stage of signal transduction mechanisms.During the late 1980s,we showed that Ca2+-stores can be mobilized by two other messengers unrelated to inositol trisphosphate(IP 3) and identified them as cyclic ADP-ribose(cADPR),a novel cyclic nucleotide from NAD,and nicotinic acid adenine dinucleotide phosphate(NAADP),a linear metabolite of NADP.Their messenger functions have now been documented in a wide range of systems spanning three biological kingdoms.Accumulated evidence indicates that the target of cADPR is the ryanodine receptor in the sarco/endoplasmic reticulum,while that of NAADP is the two pore channel in endolysosomes. As cADPR and NAADP are structurally and functionally distinct,it is remarkable that they are synthesized by the same enzyme.They are thus fraternal twin messengers.We first identified the Aplysia ADP-ribosyl cyclase as one such enzyme and,through homology,found its mammalian homolog,CD38.Gene knockout in mice confirms the important roles of CD38 in diverse physiological functions from insulin secretion,susceptibility to bacterial infection,to social behavior of mice through modulating neuronal oxytocin secretion.We have elucidated the catalytic mechanisms of the Aplysia cyclase and CD38 to atomic resolution by crystallography and site-directed mutagenesis.This article gives a historical account of the cADPR/NAADP/CD38-signaling pathway and describes current efforts in elucidating the structure and function of its components.
