技术资料

Signal transduction mediated by Fas-associated death domain protein (FADD) represents a paradigm of coregulation of apoptosis and cellular proliferation. During apoptotic signaling induced by death receptors including Fas,FADD is required for the recruitment and activation of caspase 8. In addition,a death receptor-independent function of FADD is essential for embryogenesis. In previous studies,FADD deficiency in embryonic stem cells resulted in a complete lack of B cells and dramatically reduced T cell numbers,as shown by Rag1(-/-) blastocyst complementation assays. However,T-specific FADD-deficient mice contained normal numbers of thymocytes and slightly reduced peripheral T cell numbers,whereas B cell-specific deletion of FADD led to increased peripheral B cell numbers. It remains undetermined what impact an FADD deficiency has on hematopoietic stem cells and progenitors. The current study analyzed the effect of simultaneous deletion of FADD in multiple cell types,including bone marrow cells,by using the IFN-inducible Mx1-cre transgene. The resulting FADD mutant mice did not develop lymphoproliferation diseases,unlike Fas-deficient mice. Instead,a time-dependent depletion of peripheral FADD-deficient lymphocytes was observed. In the bone marrow,a lack of FADD led to a dramatic decrease in the hematopoietic stem cells and progenitor-enriched population. Furthermore,FADD-deficient bone marrow cells were defective in their ability to generate lymphoid,myeloid,and erythroid cells. Thus,the results revealed a temporal requirement for FADD. Although dispensable during lymphopoiesis post lineage commitment,FADD plays a critical role in early hematopoietic stages in the bone marrow. View Publication

Aldehyde dehydrogenase (ALDH) is a candidate marker for lung cancer cells with stem cell-like properties. Immunohistochemical staining of a large panel of primary non-small cell lung cancer (NSCLC) samples for ALDH1A1,ALDH3A1,and CD133 revealed a significant correlation between ALDH1A1 (but not ALDH3A1 or CD133) expression and poor prognosis in patients including those with stage I and N0 disease. Flow cytometric analysis of a panel of lung cancer cell lines and patient tumors revealed that most NSCLCs contain a subpopulation of cells with elevated ALDH activity,and that this activity is associated with ALDH1A1 expression. Isolated ALDH(+) lung cancer cells were observed to be highly tumorigenic and clonogenic as well as capable of self-renewal compared with their ALDH(-) counterparts. Expression analysis of sorted cells revealed elevated Notch pathway transcript expression in ALDH(+) cells. Suppression of the Notch pathway by treatment with either a γ-secretase inhibitor or stable expression of shRNA against NOTCH3 resulted in a significant decrease in ALDH(+) lung cancer cells,commensurate with a reduction in tumor cell proliferation and clonogenicity. Taken together,these findings indicate that ALDH selects for a subpopulation of self-renewing NSCLC stem-like cells with increased tumorigenic potential,that NSCLCs harboring tumor cells with ALDH1A1 expression have inferior prognosis,and that ALDH1A1 and CD133 identify different tumor subpopulations. Therapeutic targeting of the Notch pathway reduces this ALDH(+) component,implicating Notch signaling in lung cancer stem cell maintenance. View Publication

Chronic compressive cervical spinal cord injury (cCSCI),a debilitating condition,lacks effective treatment options. Addressing this gap,our study introduces a novel rat model of cCSCI developed through spinal cord compression via synthetic polyether sheet implantation,closely mimicking human pathology. We evaluated the model’s fidelity utilizing a comprehensive series of behavioral,electrophysiological,and histological assessments. Our research also explored the therapeutic potential of oligodendrogenic neural progenitor cells (oNPCs) derived from induced pluripotent stem cells. Transplanted oNPCs successfully integrated into the host spinal cord,differentiated into neurons,astrocytes,and oligodendrocytes,and demonstrated a remarkable capacity for enhancing neuroplasticity. Electrophysiological analyses revealed significant improvements in motor evoked potentials and a rectification of the excitability imbalance posttransplantation,indicating substantial recovery of motor circuits. Histological findings complemented these results,showing enhanced remyelination and a reduction in excitatory transmitter expression in the residual gray matter. Functionally,the transplantation of oNPCs led to marked improvements in grip strength,locomotor abilities,and sensory functions,surpassing those seen with standard treatments. This study not only provides a novel and reliable rat model of cCSCI for further research but also highlights the potential of oNPCs as a transformative approach for spinal cord injury therapy,suggesting their significant role in neural regeneration and repair. View Publication

Radiotherapy is a standard treatment of pediatric brain tumors. Though the survival rate has improved for many tumor types,most patients suffer long-term cognitive decline and there is currently no way of preventing radiation-induced damage to healthy brain tissue. Here,we used a human forebrain organoid model to investigate if the α2-adrenoceptor and I1-imidazoline receptor agonist clonidine could prevent radiotoxicity. We found that treatment of organoids with clonidine significantly reduced radiation-induced loss of neural progenitor cells,neurons,astrocytes,and oligodendrocyte lineage cells. Moreover,clonidine reduced overall DNA damage and signs of reactive gliosis in organoids. Our findings demonstrate that pharmacological rescue of radiation neurotoxicity is possible in a human brain organoid model and provides a rationale for future drug repurposing studies aiming to prevent radiation-induced brain injury in children treated with radiotherapy. View Publication

The high burden of dilated cardiomyopathy (DCM) in individuals of African descent remains incompletely explained. Here,to explore a genetic basis,we conducted a genome-wide association study in 1,802 DCM cases and 93,804 controls of African genetic ancestry (AFR). A nonsense variant (rs3211938:G) in CD36 was associated with increased risk of DCM. This variant,believed to be under positive selection due to a protective role in malaria resistance,is present in 17% of AFR individuals but <0.1% of European genetic ancestry (EUR) individuals. Homozygotes for the risk allele,who comprise ~1% of the AFR population,had approximately threefold higher odds of DCM. Among those without clinical cardiomyopathy,homozygotes exhibited an 8% absolute reduction in left ventricular ejection fraction. In AFR,the DCM population attributable fraction for the CD36 variant was 8.1%. This single variant accounted for approximately 20% of the excess DCM risk in individuals of AFR compared to those of EUR. Experiments in human induced pluripotent stem cell-derived cardiomyocytes demonstrated that CD36 loss of function impairs fatty acid uptake and disrupts cardiac metabolism and contractility. These findings implicate CD36 loss of function and suboptimal myocardial energetics as a prevalent cause of DCM in individuals of African descent. Genome-wide analysis in individuals of African ancestry identifies a nonsense variant in CD36 associated with increased risk of dilated cardiomyopathy (DCM),partly accounting for the higher incidence of DCM in African-ancestry populations. View Publication

BackgroundThe cycling intestinal stem cells (ISCs) exhibit radiosensitivity,and their death or impaired regenerative capacity following irradiation may result in intestinal barrier dysfunction. The cystathionine-β-synthase (CBS)/H2S axis plays a critical role in regulating cell proliferation,reactive oxygen species scavenging,and the DNA damage response. However,it remains unclear whether the CBS/H2S axis modulates ISC homeostasis and tissue radiosensitivity. Methods: Intestinal epithelium specific conditional CBS knockout mice were generated by crossing CBSfl/+ mice with Villin-CreERT2 mice. CAGGCre-ER™ mice were crossed with CBSfl/fl mice to achieve CBS knockout in multiple tissues and cell types. The Lgr5-Tdtaomato-Flag mice were generated by CRISPR/Cas9 system. The CBS inhibitor AOAA or the H2S donor GYY4137 was used to treat mice or intestinal crypt organoids. Hematoxylin and eosin,immunohistochemistry,immunofluorescence,Western blot,qRT-PCR,et al. were employed to investigate the role of the CBS/H2S axis in ISCs homeostasis and radiation-induced intestinal damage. Results: Lgr5 + ISCs and progenitor cells expressed higher levels of CBS than differentiated cells. The cecum and colon expressed significant higher CBS levels than the small intestine. Treatment with the H2S donor GYY4137 enhanced the proliferation of intestinal organoids in vitro,while inhibition of CBS by AOAA reduced this effect. Genetic knockout of CBS in the intestinal epithelium or global downregulation of CBS driven by CAGG-CreER™ in vivo did not affect ISC proliferation or differentiation under physiological conditions. Pharmacological regulation of the CBS/H2S axis in vitro failed to protect organoids from radiation-induced damage. Interestingly,administration of AOAA in vivo reduced radiation-induced atrophy of the intestinal mucosa. Furthermore,global downregulation of CBS significantly promoted ISC recovery after irradiation exposure. However,intestinal epithelium-specific CBS knockout did not confer radioprotective effects. Conclusions: Our findings suggest that the CBS/H2S axis contributes to the regulation of ISC homeostasis and represents a potential target for radiation protection,mediated through the intervention of non-epithelial cells. View Publication

The selective peroxisome proliferator–activated receptor delta (PPARD) agonist seladelpar reduces liver injury and modulates bile acid metabolism in preclinical models. Seladelpar was recently approved for the secondary treatment of primary biliary cholangitis (PBC). Despite its beneficial effects for liver diseases,the target cells of seladelpar on a single-cell level remain unknown. This study is aimed at investigating the effect of seladelpar on single liver cells. Methods and Results: CD-1 mice were gavaged with vehicle or seladelpar (10 mg/kg body weight),and the liver was harvested 6 h later. Single-nuclei RNA sequencing (snRNA-seq) analysis showed the engagement of PPARD target genes primarily in hepatocytes and cholangiocytes by seladelpar. The top two upregulated genes,Ehhadh and Cyp4a14,are related to fatty acid metabolism and were increased in hepatocytes,cholangiocytes,and Kupffer cells. Abcb4,an important canalicular transporter with hepatoprotective effects,was significantly upregulated in hepatocytes. We confirmed upregulated Abcb4 gene expression in seladelpar-treated primary mouse hepatocytes isolated from C57BL/6 mice. We further incubated nonparenchymal liver cells with seladelpar. Although there was a significant increase in the PPARD-responsive genes Pdk4 and Angptl4 in cholangiocytes,Kupffer cells,and hepatic stellate cells,seladelpar did not exert specific liver-protective effects in these cell types. Conclusions: The selective PPARD agonist seladelpar induced PPARD-responsive genes primarily in hepatocytes and cholangiocytes. Seladelpar upregulated Abcb4 in hepatocytes,which might contribute to its beneficial effects in cholestatic liver disorders. View Publication

USH2A mutations are the leading cause of autosomal recessive retinitis pigmentosa (RP),a progressive blinding disease marked by photoreceptor degeneration. Animal models fail to recapitulate the features of USH2A RP seen in humans,and its earliest pathogenic events remain unknown. Here,we established a human model of USH2A RP using retinal organoids derived from patient induced pluripotent stem cells and CRISPR-Cas9-engineered isogenic-USH2A−/− induced pluripotent stem cells. Methods: We assessed organoids for cellular,molecular,and morphological defects using serial live imaging and whole organoid and fixed section analyses. Results: Both patient-derived and isogenic-USH2A−/− organoids showed preferential rod photoreceptor loss followed by widespread degeneration,consistent with the clinical phenotype. Additionally,isogenic-USH2A−/− organoids showed early defects in proliferation and structure. Conclusions: Our findings suggest that molecular changes precede overt photoreceptor loss in USH2A RP,and pathogenesis may begin before clinical symptoms emerge. By defining early and late disease features,we provide new insight on the developmental origins of USH2A RP to guide therapeutic strategies. View Publication

Regulatory T cells are a class of T lymphocytes which respond to activation signals by expanding their cell numbers,and whose culturing and expansion are of significant clinical interest. Cellular activation states are used to inform process control decisions such as restimulation and can be probed with experimental measurements of cell surface markers. However,these measurements are expensive,time-consuming,and invasive,and an urgent need exists for devising a non-invasive method for activation state monitoring that could be deployed on-line. Raman spectroscopy is a label-free and information-rich optical method that,when coupled to data analytical methods,can ameliorate these experimental issues. In this work,we quantitatively estimated experimental measurements of regulatory T cell activation markers with high accuracy. We simulated a clinical manufacturing setting by building an L1-regularized least-squares model with spectroscopic data from six regulatory T cell donors. Then,we validated the constructed model by accurately estimating different experimental measurements of biomarker values from two external donors,unseen by the model. We have devised a robust program to effectively estimate the activation state of regulatory T cells. We anticipate our method to be used with on-line Raman probes integrated into cell manufacturing devices for label-free monitoring of these processes. View Publication

Parechovirus ahumpari 3 (HPeV-3) is among the main agents causing severe neonatal neurological infections such as encephalitis and meningitis. However,the underlying molecular mechanisms and changes to the host cellular landscape leading to neurological disease has been understudied. Through quantitative proteomic analysis of HPeV-3 infected neural organoids,we identified unique metabolic changes following HPeV-3 infection that indicate immunometabolic dysregulation. Protein and pathway analyses showed significant alterations in neurotransmission and potentially,neuronal excitotoxicity. Elevated levels of extracellular glutamate,lactate dehydrogenase (LDH),and neurofilament light (NfL) confirmed glutamate excitotoxicity to be a key mechanism contributing to neuronal toxicity in HPeV-3 infection and can lead to apoptosis induced by caspase signaling. These insights are pivotal in delineating the metabolic landscape following severe HPeV-3 CNS infection and may identify potential host targets for therapeutic interventions. View Publication