A robust animal model for "hypothesis-testing/mechanistic" research in human immunology and immuno-pathology should meet the following criteria.First,it has well-studied hemato-lymphoid organs and target cel...A robust animal model for "hypothesis-testing/mechanistic" research in human immunology and immuno-pathology should meet the following criteria.First,it has well-studied hemato-lymphoid organs and target cells similar to those of humans.Second,the human pathogens establish infection and lead to relevant diseases.Third,it is genetically inbred and can be manipulated via genetic,immunological and pharmacological means.Many human-tropic pathogens such as HIV-1 fail to infect murine cells due to the blocks at multiple steps of their life cycle.The mouse with a reconstituted human immune system and other human target organs is a good candidate.A number of human-mouse chimeric models with human immune cells have been developed in the past 20 years,but most with only limited success due to the selective engraftment of xeno-reactive human T cells in hu-PBL-SCID mice or the lack of significant human immune responses in the SCID-hu Thy/Liv mouse.This review summarizes the current understanding of HIV-1 immuno-pathogenesis in human patients and in SIV-infected primate models.It also reviews the recent progress in the development of humanized mouse models with a functional human immune system,especially the recent progress in the immunodeficient mice that carry a defective gammaC gene.NOD/SCID/gammaC-/(NOG or NSG) or the Rag2-/-/gammaC-/double knockout (DKO) mice,which lack NK as well as T and B cells (NTB-null mice),have been used to reconstitute a functional human immune system in central and peripheral lymphoid organs with human CD34+ HSC.These NTB-hu HSC humanized models have been used to investigate HIV-1 infection,immuno-pathogenesis and therapeutic interventions.Such models,with further improvements,will contribute to study human immunology,human-tropic pathogens as well as human stem cell biology in the tissue development and function in vivo.展开更多
Salmonella enterica serovar Typhi is a pathogen that only infects humans.Currently,there is no animal model for studying this pathogen.Recently,alymphoid RAG2^(-/-)/γc^(-/-) mice engrafted with human leukocytes,known...Salmonella enterica serovar Typhi is a pathogen that only infects humans.Currently,there is no animal model for studying this pathogen.Recently,alymphoid RAG2^(-/-)/γc^(-/-) mice engrafted with human leukocytes,known as humanized mice,have been successfully utilized to develop experimental models for several human-specific viral infections,including HIV,human-like dengue fever and hepatitis C virus.Little is known about the usefulness and feasibility of the humanized mouse model for the study of human-specific bacterial pathogens,such as S.typhi.The aim of this study was to determine if Salmonella enterica serovar Typhi could establish productive infection in humanized mice.Here we report that intravenous inoculation of S.typhi into humanized mice,but not controls,established S.typhi infections.High bacterial loads were found in the liver,spleen,blood and bone marrow of mice reconstituted with human leukocytes,but not in the unreconstituted control mice.Importantly,S.typhi-infected humanized mice lost significant body weight,and some of the infected mice displayed neurological symptoms.Our data suggest,for the first time,that humanized mice are susceptible to S.typhi challenge and that this model can be utilized to study the pathogenesis of S.typhito develop novel therapeutic strategies.展开更多
Background:Abnormal alternative splicing is frequently associated with carcinogenesis.In B-cell acute lymphoblastic leukemia(B-ALL),double homeobox 4 fused with immunoglobulin heavy chain(DUX4/IGH)can lead to the aber...Background:Abnormal alternative splicing is frequently associated with carcinogenesis.In B-cell acute lymphoblastic leukemia(B-ALL),double homeobox 4 fused with immunoglobulin heavy chain(DUX4/IGH)can lead to the aberrant production of E-26 transformation-specific family related gene abnormal transcript(ERGalt)and other splicing variants.However,the molecular mechanism underpinning this process remains elusive.Here,we aimed to know how DUX4/IGH triggers abnormal splicing in leukemia.Methods:The differential intron retention analysis was conducted to identify novel DUX4/IGH-driven splicing in B-ALL patients.X-ray crystallography,small angle X-ray scattering(SAXS),and analytical ultracentrifugation were used to investigate how DUX4/IGH recognize double DUX4 responsive element(DRE)-DRE sites.The ERGalt biogenesis and B-cell differentiation assays were performed to characterize the DUX4/IGH crosslinking activity.To check whether recombination-activating gene 1/2(RAG1/2)was required for DUX4/IGH-driven splicing,the proximity ligation assay,co-immunoprecipitation,mammalian two hybrid characterizations,in vitro RAG1/2 cleavage,and shRNA knock-down assays were performed.Results:We reported previously unrecognized intron retention events in Ctype lectin domain family 12,member A abnormal transcript(CLEC12Aalt)and chromosome 6 open reading frame 89 abnormal transcript(C6orf89alt),where also harbored repetitive DRE-DRE sites.Supportively,X-ray crystallography and SAXS characterization revealed that DUX4 homeobox domain(HD)1-HD2 might dimerize into a dumbbell-shape trans configuration to crosslink two adjacent DRE sites.Impaired DUX4/IGH-mediated crosslinking abolishes ERGalt,CLEC12Aalt,and C6orf89alt biogenesis,resulting in marked alleviation of its inhibitory effect on B-cell differentiation.Furthermore,we also observed a rare RAG1/2-mediated recombination signal sequence-like DNA edition in DUX4/IGH target genes.Supportively,shRNA knock-down of RAG1/2 in leukemic Reh cells consistently impaired the biogenesis of ERGalt,CLEC12Aalt,and C6orf89alt.Conclusions:All these results suggest that DUX4/IGH-driven DNA crosslinking is required for RAG1/2 recruitment onto the double tandem DRE-DRE sites,catalyzing V(D)J-like recombination and oncogenic splicing in acute lymphoblastic leukemia.展开更多
基金supported by the National Natural Science Foundation of China (Grant No. 30872365)the Ministry of Science and Technology Grants (Grant Nos. 2006CB910901 and KSCX2-YW-R-150)+1 种基金the Ministry of Health (Grant Nos. 2009ZX10604 and 2008ZX10002-011)the National Institute of Health (Grant Nos. AI080432, AI041356, AA018009 and AI077454)
文摘A robust animal model for "hypothesis-testing/mechanistic" research in human immunology and immuno-pathology should meet the following criteria.First,it has well-studied hemato-lymphoid organs and target cells similar to those of humans.Second,the human pathogens establish infection and lead to relevant diseases.Third,it is genetically inbred and can be manipulated via genetic,immunological and pharmacological means.Many human-tropic pathogens such as HIV-1 fail to infect murine cells due to the blocks at multiple steps of their life cycle.The mouse with a reconstituted human immune system and other human target organs is a good candidate.A number of human-mouse chimeric models with human immune cells have been developed in the past 20 years,but most with only limited success due to the selective engraftment of xeno-reactive human T cells in hu-PBL-SCID mice or the lack of significant human immune responses in the SCID-hu Thy/Liv mouse.This review summarizes the current understanding of HIV-1 immuno-pathogenesis in human patients and in SIV-infected primate models.It also reviews the recent progress in the development of humanized mouse models with a functional human immune system,especially the recent progress in the immunodeficient mice that carry a defective gammaC gene.NOD/SCID/gammaC-/(NOG or NSG) or the Rag2-/-/gammaC-/double knockout (DKO) mice,which lack NK as well as T and B cells (NTB-null mice),have been used to reconstitute a functional human immune system in central and peripheral lymphoid organs with human CD34+ HSC.These NTB-hu HSC humanized models have been used to investigate HIV-1 infection,immuno-pathogenesis and therapeutic interventions.Such models,with further improvements,will contribute to study human immunology,human-tropic pathogens as well as human stem cell biology in the tissue development and function in vivo.
基金This study was supported by a grant from CIHR to Ali A Ashkar.AAA is a recipient of a Career Award in Health Sciences from Rx&D/CIHR.
文摘Salmonella enterica serovar Typhi is a pathogen that only infects humans.Currently,there is no animal model for studying this pathogen.Recently,alymphoid RAG2^(-/-)/γc^(-/-) mice engrafted with human leukocytes,known as humanized mice,have been successfully utilized to develop experimental models for several human-specific viral infections,including HIV,human-like dengue fever and hepatitis C virus.Little is known about the usefulness and feasibility of the humanized mouse model for the study of human-specific bacterial pathogens,such as S.typhi.The aim of this study was to determine if Salmonella enterica serovar Typhi could establish productive infection in humanized mice.Here we report that intravenous inoculation of S.typhi into humanized mice,but not controls,established S.typhi infections.High bacterial loads were found in the liver,spleen,blood and bone marrow of mice reconstituted with human leukocytes,but not in the unreconstituted control mice.Importantly,S.typhi-infected humanized mice lost significant body weight,and some of the infected mice displayed neurological symptoms.Our data suggest,for the first time,that humanized mice are susceptible to S.typhi challenge and that this model can be utilized to study the pathogenesis of S.typhito develop novel therapeutic strategies.
基金National Natural Science Foundation of China,Grant/Award Numbers:81970132,81770142,81800144,31800642Shanghai Science and Technology Committee,Grant/Award Number:20JC1410600+3 种基金Shanghai Guangci Translational Medical Research Development FoundationShanghai Municipal Education Commission-Gaofeng Clinical Medicine Grant Support,Grant/Award Number:20152504The Program for Professor of Special Appointment(Eastern Scholar)at Shanghai Institute of Higher LearningSamuel Waxman Cancer Research Foundation。
文摘Background:Abnormal alternative splicing is frequently associated with carcinogenesis.In B-cell acute lymphoblastic leukemia(B-ALL),double homeobox 4 fused with immunoglobulin heavy chain(DUX4/IGH)can lead to the aberrant production of E-26 transformation-specific family related gene abnormal transcript(ERGalt)and other splicing variants.However,the molecular mechanism underpinning this process remains elusive.Here,we aimed to know how DUX4/IGH triggers abnormal splicing in leukemia.Methods:The differential intron retention analysis was conducted to identify novel DUX4/IGH-driven splicing in B-ALL patients.X-ray crystallography,small angle X-ray scattering(SAXS),and analytical ultracentrifugation were used to investigate how DUX4/IGH recognize double DUX4 responsive element(DRE)-DRE sites.The ERGalt biogenesis and B-cell differentiation assays were performed to characterize the DUX4/IGH crosslinking activity.To check whether recombination-activating gene 1/2(RAG1/2)was required for DUX4/IGH-driven splicing,the proximity ligation assay,co-immunoprecipitation,mammalian two hybrid characterizations,in vitro RAG1/2 cleavage,and shRNA knock-down assays were performed.Results:We reported previously unrecognized intron retention events in Ctype lectin domain family 12,member A abnormal transcript(CLEC12Aalt)and chromosome 6 open reading frame 89 abnormal transcript(C6orf89alt),where also harbored repetitive DRE-DRE sites.Supportively,X-ray crystallography and SAXS characterization revealed that DUX4 homeobox domain(HD)1-HD2 might dimerize into a dumbbell-shape trans configuration to crosslink two adjacent DRE sites.Impaired DUX4/IGH-mediated crosslinking abolishes ERGalt,CLEC12Aalt,and C6orf89alt biogenesis,resulting in marked alleviation of its inhibitory effect on B-cell differentiation.Furthermore,we also observed a rare RAG1/2-mediated recombination signal sequence-like DNA edition in DUX4/IGH target genes.Supportively,shRNA knock-down of RAG1/2 in leukemic Reh cells consistently impaired the biogenesis of ERGalt,CLEC12Aalt,and C6orf89alt.Conclusions:All these results suggest that DUX4/IGH-driven DNA crosslinking is required for RAG1/2 recruitment onto the double tandem DRE-DRE sites,catalyzing V(D)J-like recombination and oncogenic splicing in acute lymphoblastic leukemia.
