技术资料

Human Alzheimer's disease (AD) brains and transgenic AD mouse models manifest hyperexcitability. This aberrant electrical activity is caused by synaptic dysfunction that represents the major pathophysiological correlate of cognitive decline. However,the underlying mechanism for this excessive excitability remains incompletely understood. To investigate the basis for the hyperactivity,we performed electrophysiological and immunofluorescence studies on hiPSC-derived cerebrocortical neuronal cultures and cerebral organoids bearing AD-related mutations in presenilin-1 or amyloid precursor protein vs. isogenic gene corrected controls. In the AD hiPSC-derived neurons/organoids,we found increased excitatory bursting activity,which could be explained in part by a decrease in neurite length. AD hiPSC-derived neurons also displayed increased sodium current density and increased excitatory and decreased inhibitory synaptic activity. Our findings establish hiPSC-derived AD neuronal cultures and organoids as a relevant model of early AD pathophysiology and provide mechanistic insight into the observed hyperexcitability. View Publication

The intestine is a highly dynamic environment that requires tight control of the various inputs to maintain homeostasis and allow for proper responses to injury. It was recently found that the stem cell niche and epithelium is regenerated after injury by de-differentiated adult cells,through a process that gives rise to Sca1+ fetal-like cells and is driven by a transient population of Clu+ revival stem cells (revSCs). However,the molecular mechanisms that regulate this dynamic process have not been fully defined. Here we show that TNFAIP8 (also known as TIPE0) is a regulator of intestinal homeostasis that is vital for proper regeneration. TIPE0 functions through inhibiting basal Akt activation by the commensal microbiota via modulating membrane phospholipid abundance. Loss of TIPE0 in mice results in injury-resistant enterocytes,that are hyperproliferative,yet have regenerative deficits and are shifted towards a de-differentiated state. Tipe0-/- enterocytes show basal induction of the Clu+ regenerative program and a fetal gene expression signature marked by Sca1,but upon injury are unable to generate Sca-1+/Clu+ revSCs and could not regenerate the epithelium. This work demonstrates the role of TIPE0 in regulating the dynamic signaling that determines the injury response and enables intestinal epithelial cell regenerative plasticity. View Publication

Background: Differences in DNA methylation have been reported in B and T lymphocyte populations,including CD4+ T cells,isolated from rheumatoid arthritis (RA) patients when compared to healthy controls. CD4+ T cells are a heterogeneous cell type with subpopulations displaying distinct DNA methylation patterns. In this study,we investigated DNA methylation using reduced representation bisulfite sequencing in two CD4+ T cell populations (CD4+ memory and na{\{i}}ve cells) in three groups: newly diagnosed disease modifying antirheumatic drugs (DMARD) na{\"{i}}ve RA patients (N = 11) methotrexate (MTX) treated RA patients (N = 18) and healthy controls (N = 9) matched for age gender and smoking status. Results: Analyses of these data revealed significantly more differentially methylated positions (DMPs) in CD4+ memory than in CD4+ na{\""{i}}ve T cells (904 vs. 19 DMPs) in RA patients compared to controls. The majority of DMPs (72{\%}) identified in newly diagnosed and DMARD na{\""{i}}ve RA patients with active disease showed increased DNA methylation (39 DMPs) whereas most DMPs (80{\%}) identified in the MTX treated RA patients in remission displayed decreased DNA methylation (694 DMPs). Interestingly we also found that about one third of the 101 known RA risk loci overlapped (±500 kb) with the DMPs. Notably introns of the UBASH3A gene harbor both the lead RA risk SNP and two DMPs in CD4+ memory T cells. Conclusion: Our results suggest that RA associated DNA methylation differences vary between the two T cell subsets but are also influenced by RA characteristics such as disease activity disease duration and/or MTX treatment.""" View Publication

Human noroviruses (HuNoVs) are the leading cause of nonbacterial gastroenteritis worldwide. Histo-blood group antigen (HBGA) expression is an important susceptibility factor for HuNoV infection based on controlled human infection models and epidemiologic studies that show an association of secretor status with infection caused by several genotypes. The fucosyltransferase 2 gene (FUT2) affects HBGA expression in intestinal epithelial cells; secretors express a functional FUT2 enzyme,while nonsecretors lack this enzyme and are highly resistant to infection and gastroenteritis caused by many HuNoV strains. These epidemiologic associations are confirmed by infections in stem cell-derived human intestinal enteroid (HIE) cultures. GII.4 HuNoV does not replicate in HIE cultures derived from nonsecretor individuals,while HIEs from secretors are permissive to infection. However,whether FUT2 expression alone is critical for infection remains unproven,since routinely used secretor-positive transformed cell lines are resistant to HuNoV replication. To evaluate the role of FUT2 in HuNoV replication,we used CRISPR or overexpression to genetically manipulate FUT2 gene function to produce isogenic HIE lines with or without FUT2 expression. We show that FUT2 expression alone affects both HuNoV binding to the HIE cell surface and susceptibility to HuNoV infection. These findings indicate that initial binding to a molecule(s) glycosylated by FUT2 is critical for HuNoV infection and that the HuNoV receptor is present in nonsecretor HIEs. In addition to HuNoV studies,these isogenic HIE lines will be useful tools to study other enteric microbes where infection and/or disease outcome is associated with secretor status.IMPORTANCE Several studies have demonstrated that secretor status is associated with susceptibility to human norovirus (HuNoV) infection; however,previous reports found that FUT2 expression is not sufficient to allow infection with HuNoV in a variety of continuous laboratory cell lines. Which cellular factor(s) regulates susceptibility to HuNoV infection remains unknown. We used genetic manipulation of HIE cultures to show that secretor status determined by FUT2 gene expression is necessary and sufficient to support HuNoV replication based on analyses of isogenic lines that lack or express FUT2. Fucosylation of HBGAs is critical for initial binding and for modification of another putative receptor(s) in HIEs needed for virus uptake or uncoating and necessary for successful infection by GI.1 and several GII HuNoV strains. View Publication

Acute graft-versus-host disease causes significant mortality in patients undergoing allogeneic hematopoietic cell transplantation. Immunosuppressive treatment for graft-versus-host disease can impair the beneficial graft-versus-leukemia effect and facilitate malignancy relapse. Therefore,novel approaches that protect and regenerate injured tissues without impeding the donor immune system are needed. Bile acids regulate multiple cellular processes and are in close contact with the intestinal epithelium,a major target of acute graft-versus-host disease. Here,we found that the bile acid pool is reduced following graft-versus-host disease induction in a preclinical model. We evaluated the efficacy of bile acids to protect the intestinal epithelium without reducing anti-tumor immunity. We observed that application of bile acids decreased cytokine-induced cell death in intestinal organoids and cell lines. Systemic prophylactic administration of tauroursodeoxycholic acid,the most potent compound in our in vitro studies,reduced graft-versus-host disease severity in three different murine transplantation models. This effect was mediated by decreased activity of the antigen presentation machinery and subsequent prevention of apoptosis of the intestinal epithelium. Moreover,bile acid administration did not alter the bacterial composition in the intestine suggesting that its effects are cell-specific and independent of the microbiome. Treatment of human and murine leukemic cell lines with tauroursodeoxycholic acid did not interfere with the expression of antigen presentation-related molecules. Systemic T cell expansion and especially their cytotoxic capacity against leukemic cells remained intact. This study establishes a role for bile acids in the prevention of acute graft-versus-host disease without impairing the graft-versus-leukemia effect. In particular,we provide a scientific rationale for the systematic use of tauroursodeoxycholic acid in patients undergoing allogeneic hematopoietic cell transplantation. View Publication

Circulating tumor cells (CTC) play important roles in various cancers; however,few studies have assessed their clinical utility in neuroendocrine tumors. This study aimed to prospectively evaluate the prognostic value of CTC counts in Asian patients with neuroendocrine tumors before and during anti-cancer therapy. Patients who were diagnosed with unresectable histological neuroendocrine tumors between September 2011 and September 2017 were enrolled. CTC testing was performed before and during anti-cancer therapy using a negative selection protocol. Chromogranin A levels were also assessed. Univariate and multivariate Cox's proportional hazard model with forward LR model was performed to investigate the impact of independent factors on overall survival and progression-free survival. Kaplan-Meier method with log-rank tests were used to determine the difference among different clinicopathological signatures and CTC cutoff. The baseline CTC detection rate was 94.3{\%} (33/35). CTC counts were associated with cancer stages (I-III vs. IV,P = 0.015),liver metastasis (P = 0.026),and neuroendocrine tumor grading (P = 0.03). The median progression-free survival and overall survivals were 12.3 and 30.4 months,respectively. In multivariate Cox regression model,neuroendocrine tumors grading and baseline CTC counts were both independent prognostic factors for progression-free survival (PFS,P = 0.005 and 0.015,respectively) and overall survival (OS,P = 0.018 and 0.023,respectively). In Kaplan-Meier analysis,lower baseline chromogranin A levels were associated with longer PFS (P = 0.024). Baseline CTC counts are associated with the clinicopathologic features of neuroendocrine tumors and are an independent prognostic factor for this malignancy. View Publication

Heterotopic ossification (HO) is defined as abnormal differentiation of local stromal cells of mesenchymal origin,resulting in pathologic cartilage and bone matrix deposition. Cyr61,CTGF,Nov (CCN) family members are matricellular proteins that have diverse regulatory functions on cell proliferation and differentiation,including the regulation of chondrogenesis. However,little is known regarding CCN family member expression or function in HO. Here,a combination of bulk and single-cell RNA sequencing defined the dynamic temporospatial pattern of CCN family member induction within a mouse model of trauma-induced HO. Among CCN family proteins,Wisp1 (also known as Ccn4) was most upregulated during the evolution of HO,and Wisp1 expression corresponded with chondrogenic gene profile. Immunohistochemistry confirmed WISP1 expression across traumatic and genetic HO mouse models as well as in human HO samples. Transgenic Wisp1LacZ/LacZ knockin animals showed an increase in endochondral ossification in HO after trauma. Finally,the transcriptome of Wisp1-null tenocytes revealed enrichment in signaling pathways,such as the STAT3 and PCP signaling pathways,that may explain increased HO in the context of Wisp1 deficiency. In sum,CCN family members,and in particular Wisp1,are spatiotemporally associated with and negatively regulate trauma-induced HO formation. View Publication

The inability of Nef to downmodulate the CD3-T cell receptor (TCR) complex distinguishes HIV-1 from other primate lentiviruses and may contribute to its high virulence. However,the role of this Nef function in virus-mediated immune activation and pathogenicity remains speculative. Here,we selectively disrupted this Nef activity in SIVmac239 and analyzed the consequences for the virological,immunological,and clinical outcome of infection in rhesus macaques. The inability to downmodulate CD3-TCR does not impair viral replication during acute infection but is associated with increased immune activation and antiviral gene expression. Subsequent early reversion in three of six animals suggests strong selective pressure for this Nef function and is associated with high viral loads and progression to simian AIDS. In the absence of reversions,however,viral replication and the clinical course of infection are attenuated. Thus,Nef-mediated downmodulation of CD3 dampens the inflammatory response to simian immunodeficiency virus (SIV) infection and seems critical for efficient viral immune evasion. View Publication

Interferon regulatory factor 1 (IRF1) regulates diverse biological functions,including modulation of cellular responses involved in tumorigenesis. Genetic mutations and altered IRF1 function are associated with several cancers. Although the function of IRF1 in the immunobiology of cancer is emerging,IRF1-specific mechanisms regulating tumorigenesis and tissue homeostasis in vivo are not clear. Here,we found that mice lacking IRF1 were hypersusceptible to colorectal tumorigenesis. IRF1 functions in both the myeloid and epithelial compartments to confer protection against AOM/DSS-induced colorectal tumorigenesis. We further found that IRF1 also prevents tumorigenesis in a spontaneous mouse model of colorectal cancer. The attenuated cell death in the colons of Irf1-/- mice was due to defective pyroptosis,apoptosis,and necroptosis (PANoptosis). IRF1 does not regulate inflammation and the inflammasome in the colon. Overall,our study identified IRF1 as an upstream regulator of PANoptosis to induce cell death during colitis-associated tumorigenesis. View Publication

Personalized cancer therapy is based on a patient's tumor lineage,histopathology,expression analyses,and/or tumor DNA or RNA analysis. Here,we aim to develop an in vitro functional assay of a patient's living cancer cells that could complement these approaches. We present methods for developing cell cultures from tumor biopsies and identify the types of samples and culture conditions associated with higher efficiency of model establishment. Toward the application of patient-derived cell cultures for personalized care,we established an immunofluorescence-based functional assay that quantifies cancer cell responses to targeted therapy in mixed cell cultures. Assaying patient-derived lung cancer cultures with this method showed promise in modeling patient response for diagnostic use. This platform should allow for the development of co-clinical trial studies to prospectively test the value of drug profiling on tumor-biopsy-derived cultures to direct patient care. Kodack et al. report on the development of cancer models from tumor biopsies and technologies toward a functional approach for personalized medicine. They describe the ability to reliably test drug response in patient-derived samples of mixed cell populations. In doing so,they show that patient biopsy cultures may predict patient clinical responses. View Publication

Quiescence is a fundamental property that maintains hematopoietic stem cell (HSC) potency throughout life. Quiescent HSCs are thought to rely on glycolysis for their energy,but the overall metabolic properties of HSCs remain elusive. Using combined approaches,including single-cell RNA sequencing (RNA-seq),we show that mitochondrial membrane potential (MMP) distinguishes quiescent from cycling-primed HSCs. We found that primed,but not quiescent,HSCs relied readily on glycolysis. Notably,in vivo inhibition of glycolysis enhanced the competitive repopulation ability of primed HSCs. We further show that HSC quiescence is maintained by an abundance of large lysosomes. Repression of lysosomal activation in HSCs led to further enlargement of lysosomes while suppressing glucose uptake. This also induced increased lysosomal sequestration of mitochondria and enhanced the competitive repopulation ability of primed HSCs by over 90-fold in vivo. These findings show that restraining lysosomal activity preserves HSC quiescence and potency and may be therapeutically relevant. View Publication

Overcoming drug resistance and targeting cancer stem cells remain challenges for curative cancer treatment. To investigate the role of miRNAs in regulating drug resistance and leukemic stem cell (LSCs) fate,we performed global transcriptome profiling in treatment-na{\{i}}ve chronic myeloid leukemia (CML) stem/progenitor cells and identified that miR-185 levels anticipate their response to ABL tyrosine kinase inhibitors (TKIs). miR-185 functions as a tumor suppressor; its restored expression impaired survival of drug-resistant cells sensitized them to TKIs in vitro and markedly eliminated long-term repopulating LSCs and infiltrating blast cells conferring a survival advantage in pre-clinical xenotransplantation models. Integrative analysis with mRNA profiles uncovered PAK6 as a crucial target of miR-185 and pharmacological inhibition of PAK6 perturbed the RAS/MAPK pathway and mitochondrial activity sensitizing therapy-resistant cells to TKIs. Thus miR-185 presents as a potential predictive biomarker and dual targeting of miR-185-mediated PAK6 activity and BCR-ABL may provide a valuable strategy for overcoming drug resistance in patients." View Publication