技术资料

Somatic cell reprogramming into human induced pluripotent stem cells entails significant intracellular changes,including modifications in mitochondrial metabolism and a decrease in mitochondrial DNA copy number. However,the mechanisms underlying this decrease in mitochondrial DNA copy number during reprogramming remain unclear. Here we aimed to elucidate these underlying mechanisms. Through a meta-analysis of several RNA sequencing datasets,we identified genes responsible for the decrease in mitochondrial DNA. We investigated the functions of these identified genes and assessed their regulatory mechanisms. In particular,the expression of the thymidine kinase 2 gene (TK2),located in the mitochondria and required for mitochondrial DNA synthesis,is decreased in human pluripotent stem cells as compared with its expression in somatic cells. TK2 was significantly downregulated during reprogramming and markedly upregulated during differentiation. Collectively,this decrease in TK2 levels induces a decrease in mitochondrial DNA copy number and contributes to shaping the metabolic characteristics of human pluripotent stem cells. However,contrary to our expectations,treatment with a TK2 inhibitor impaired somatic cell reprogramming. These results suggest that decreased TK2 expression may result from metabolic conversion during somatic cell reprogramming. Mitochondrial DNA loss linked to stem cell reprogrammingInduced pluripotent stem (iPS) cells are special cells created by reprogramming regular body cells. Researchers explored how these cells change their energy production methods during reprogramming. The study focused on a protein called thymidine kinase 2 (TK2),which is important for maintaining mitochondrial DNA (mtDNA). Mitochondria are the cell’s powerhouses,and their DNA is crucial for energy production. Researchers used human cell lines to study how TK2 affects mtDNA during reprogramming. They found that,as cells become iPS cells,TK2 levels drop,leading to reduced mtDNA and a shift in energy production from oxidative phosphorylation to glycolysis. Results suggest that reducing TK2 and mtDNA is key for cells to gain pluripotency. This shift helps support the rapid growth and development of iPS cells. Understanding this process could improve stem cell therapies and regenerative medicine in the future.This summary was initially drafted using artificial intelligence,then revised and fact-checked by the author. View Publication

The angiotensin-converting enzyme 2 (ACE2) is a primary cell surface viral binding receptor for SARS-CoV-2,so finding new regulatory molecules to modulate ACE2 expression levels is a promising strategy against COVID-19. In the current study,we utilized islet organoids derived from human embryonic stem cells (hESCs),animal models and COVID-19 patients to discover that fibroblast growth factor 7 (FGF7) enhances ACE2 expression within the islets,facilitating SARS-CoV-2 infection and resulting in impaired insulin secretion. Using hESC-derived islet organoids,we demonstrated that FGF7 interacts with FGF receptor 2 (FGFR2) and FGFR1 to upregulate ACE2 expression predominantly in ? cells. This upregulation increases both insulin secretion and susceptibility of ? cells to SARS-CoV-2 infection. Inhibiting FGFR counteracts the FGF7-induced ACE2 upregulation,subsequently reducing viral infection and replication in the islets. Furthermore,retrospective clinical data revealed that diabetic patients with severe COVID-19 symptoms exhibited elevated serum FGF7 levels compared to those with mild symptoms. Finally,animal experiments indicated that SARS-CoV-2 infection increased pancreatic FGF7 levels,resulting in a reduction of insulin concentrations in situ. Taken together,our research offers a potential regulatory strategy for ACE2 by controlling FGF7,thereby protecting islets from SARS-CoV-2 infection and preventing the progression of diabetes in the context of COVID-19. View Publication

Advancements in vaccination and sanitation have significantly reduced the prevalence and burden of infectious diseases; however,these benefits have coincided with a marked rise in autoimmune and allergic disorders. Recent studies have investigated these linked trends through the lens of host-microbiome alterations,proposing these shifts as a potential explanatory mechanism. Previously,we demonstrated that vancomycin-induced depletion of short-chain fatty acid (SCFA)-producing bacteria results in hyperactivation of ILC2s and exacerbated allergic responses. Here we investigate the effects of low-dose streptomycin on innate and adaptive immune cell populations and their activation states. Although streptomycin-treated mice exhibit normal allergic responses,they display heightened susceptibility to Th1/Th17-mediated disease,specifically hypersensitivity pneumonitis (HP). This is characterized by a two-fold increase in ILC3s and Th17 cells in the lungs,alongside activation of antigen-presenting cells (APCs) at steady state-an effect that is further amplified upon exposure to HP-inducing agents. Shotgun metagenomic analysis revealed that streptomycin-induced dysbiosis reduces microbial diversity,depletes bile acid-metabolizing bacteria,and enriches for metabolic pathways involved in branched-chain amino acid biosynthesis,including leucine-a known activator of mTORC1. Strikingly,administration of the secondary bile acid metabolite isolithocholic acid (an inverse agonist of RORγt),or an IL-23 neutralizing antibody,reverses the enhanced susceptibility to HP. Inhibition of mTORC1 significantly reduced Th17/ILC3 responses and histopathology. Our findings underscore microbial equilibrium as a key determinant of susceptibility to HP and uncover a positive feedback loop between IL and 23-producing APCs and ILC3/Th17 cells that mechanistically links dysbiosis to sustained type 3 inflammation,and we identify a simple,actionable means of intervention. View Publication

The association between type 2 diabetes (T2D) pathogenesis and immune-mediated tissue damage and insulin resistance suggests that T2D patients might benefit from the suppression of pathogenic inflammation. Foxp3+ Treg cells are crucial suppressors of inflammation,but the differentiation of Foxp3+ Treg cells is not static and is subject to conversion into IL-17-producing Th17-like cells upon receiving external signals. In this study,we examined the production of IL-17 by Treg cells. Compared to non-T2D controls,T2D patients presented significantly higher levels of IL-17-expressing cells in both Foxp3- CD4 T cells and Foxp3+ Treg cells. The frequencies of IL-17-nonexpressing Foxp3+ Treg cells,on the other hand,were not changed. Interestingly,IL-17-expressing Foxp3+ Treg cells were mutually exclusive from IL-10-expressing and TGF-$\beta$-expressing Foxp3+ Treg cells,suggesting that multiple subpopulations exist within the Foxp3+ Treg cells from T2D patients. In T2D patients,the frequencies of IL-17-expressing Foxp3+ Treg cells were positively correlated with the body mass index (BMI) and the HbA1c levels of T2D patients. The frequencies of IL-10-expressing Treg cells,on the other hand,were inversely associated with the BMI of both non-T2D controls and T2D patients. In addition,the suppressive activity of Treg cells was significantly lower in T2D patients than in non-T2D controls. Together,our study uncovered a dysregulation in Foxp3+ Treg cells from T2D patients,characterized by high IL-17 expression and low suppression activity. View Publication

Osteoporotic osteoarthritis (OPOA) is a common bone disease mostly in the elderly,but the relationship between Osteoporotic (OP) and osteoarthritis (OA) is complex. It has been shown that knee loading can mitigate OA symptoms. However,its effects on OPOA remain unclear. In this study,we characterized pathological linkage of OP to OA,and evaluated the effect of knee loading on OPOA. We employed two mouse models (OA and OPOA),and conducted histology,cytology,and molecular analyses. In the OA and OPOA groups,articular cartilage was degenerated and Osteoarthritis Research Society International score was increased. Subchondral bone underwent abnormal remodeling,the differentiation of bone marrow mesenchymal stem cells (BMSCs) to osteoblasts and chondrocytes was reduced,and migration and adhesion of pre-osteoclasts were enhanced. Compared to the OA group,the pathological changes of OA in the OPOA group were considerably aggravated. After knee loading,however,cartilage degradation was effectively prevented,and the abnormal remodeling of subchondral bone was significantly inhibited. The differentiation of BMSCs was also improved,and the expression of Wnt/$\beta$-catenin was elevated. Collectively,this study demonstrates that osteoporosis aggravates OA symptoms. Knee loading restores OPOA by regulating subchondral bone remodeling,and may provide an effective method for repairing OPOA. View Publication

CD16a (Fc$\gamma$RIIIa) mediates the antibody dependent cellular cytotoxicity (ADCC) and is important for anti-tumor activities of many therapeutic antibodies. Bispecific antibody targeting natural killer (NK) cells has been studied for cancer therapy. In this work,anti-CD16a single-domain antibodies were identified from hCD16a immunized camel. Bispecific antibodies are then constructed by fusing these single domain antibodies with an anti-CEA single domain antibody. These bispecific antibodies can recruite NK cells to kill CEA-positive tumor cells,and inhibit tumor growth in vivo,suggesting that these anti-CD16a single domain antibodies are powerful tools to engaging NK cells for cancer therapy. View Publication

Diffuse large B cell lymphoma (DLBCL) is the commonest disorder derived from the B-lymphocytes. Inhibiting the immune checkpoint through naturalizing programmed death-1 (PD-1) and programmed death ligand 1 (PD-L1) is proved to be a successful therapeutic regime for lymphoma. Long non-coding RNAs (lncRNAs) are unceasingly reported to be promising biological targets for the cancer therapies. This study planned to explore the regulation of small nucleolar RNA host gene 14 (SNHG14) on DLBCL. SNHG14 level in DLBCL samples and cell lines was analyzed by GEPIA bioinformatics tool and RT-qPCR. Biological functions of SNHG14 in DLBCL were detected by CCK-8,colony formation,and transwell invasion assays. Molecular interaction was determined by RNA immunoprecipitation (RIP) and luciferase reporter assays. MiR-5590-3p-related pathway was identified through KEGG pathway analysis applying DAVID6.8 online bioinformatics tool. Effect of SNHG14 on CD8+ T cells was detected by flow cytometry. Results depicted that SNHG14 was upregulated in DLBCL and its depletion retarded proliferation,migration and epithelial-to-mesenchymal transition (EMT). Mechanistically,SNHG14 sponged miR-5590-3p to upregulate Zinc finger E-box binding homeobox 1 (ZEB1),and ZEB1 transcriptionally activated SNHG14 and PD-L1 to promote the immune evasion of DLBCL cells. In conclusion,we firstly showed that SNHG14/miR-5590-3p/ZEB1 positive feedback loop promoted diffuse large B cell lymphoma progression and immune evasion through regulating PD-1/PD-L1 checkpoint,indicating that targeting SNHG14 was a potential approach to improve the efficacy of immunotherapy in DLBCL. View Publication

Neurogenin3 (NEUROG3) is required for endocrine lineage formation of the pancreas and intestine. Patients with NEUROG3 mutations are born with congenital malabsorptive diarrhea due to complete loss of enteroendocrine cells,whereas endocrine pancreas development varies in an allele-specific manner. These findings suggest a context-dependent requirement for NEUROG3 in pancreas versus intestine. We utilized human tissue differentiated from NEUROG3-/- pluripotent stem cells for functional analyses. Most disease-associated alleles had hypomorphic or null phenotype in both tissues,whereas the S171fsX68 mutation had reduced activity in the pancreas but largely null in the intestine. Biochemical studies revealed NEUROG3 variants have distinct molecular defects with altered protein stability,DNA binding,and gene transcription. Moreover,NEUROG3 was highly unstable in the intestinal epithelium,explaining the enhanced sensitivity of intestinal defects relative to the pancreas. These studies emphasize that studies of human mutations in the endogenous tissue context may be required to assess structure-function relationships. View Publication

Graphene quantum dots (GQDs) have gained significant attention in various biomedical applications. The physicochemical properties of these nanoparticles,including toxic effects,are largely determined by their surface modifications. Previous studies have demonstrated high in vitro cytotoxicity of the hydroxylated GQDs (OH-GQDs). The focus of this study was on the intestinal toxicity of OH-GQDs. Briefly,C57BL/6J mice were given daily oral gavage of 0.05,0.5 or 5 mg/kg OH-GQD for 7 days,and the indices of intestinal damage were evaluated. Higher doses of the OH-GQDs caused significant intestinal injuries,such as enhanced intestinal permeability,shortened villi and crypt loss. The number of Lgr5+ intestinal stem cells also decreased dramatically upon OH-GQDs exposure,which also inhibited the Ki67+ proliferative progenitor cells. In addition,an increased number of crypt cells harboring the oxidized DNA base 8-OHdG and $\gamma$H2AX foci were also detected in the intestines of OH-GQD-treated mice. Mechanistically,the OH-GQDs up-regulated both total and phosphorylated p53. Consistent with this,the average number of TUNEL+ and cleaved caspase-3+ apoptotic intestinal epithelial cells were significantly increased after OH-GQDs treatment. Finally,a 3-dimensional organoid culture was established using isolated crypts,and OH-GQDs treatment significantly reduced the size of the surviving intestinal organoids. Taken together,the intestinal toxicity of the OH-GQDs should be taken into account during biomedical applications. View Publication

Shiga toxigenic Escherichia coli (STEC) are responsible for a worldwide foodborne disease,which is characterized by severe bloody diarrhea and hemolytic uremic syndrome (HUS). Subtilase cytotoxin (SubAB) is a novel AB5 toxin,which is produced by Locus for Enterocyte Effacement (LEE)-negative STEC. Cleavage of the BiP protein by SubAB induces endoplasmic reticulum (ER) stress,followed by induction of cytotoxicity in vitro or lethal severe hemorrhagic inflammation in mice. Here we found that steroids and diacylglycerol (DAG) analogues (e.g.,bryostatin 1,Ingenol-3-angelate) inhibited SubAB cytotoxicity. In addition,steroid-induced Bcl-xL expression was a key step in the inhibition of SubAB cytotoxicity. Bcl-xL knockdown increased SubAB-induced apoptosis in steroid-treated HeLa cells,whereas SubAB-induced cytotoxicity was suppressed in Bcl-xL overexpressing cells. In contrast,DAG analogues suppressed SubAB activity independent of Bcl-xL expression at early time points. Addition of Shiga toxin 2 (Stx2) with SubAB to cells enhanced cytotoxicity even in the presence of steroids. In contrast,DAG analogues suppressed cytotoxicity seen in the presence of both toxins. Here,we show the mechanism by which steroids and DAG analogues protect cells against SubAB toxin produced by LEE-negative STEC. View Publication

Despite implementation of virtual crossmatches,flow cytometry crossmatches (FCXM) are still used by many transplant centers to determine immunological risk before kidney transplantation. To determine if common profiles of patients prone to false positive FCXM exist,we examined the demographics and native diseases of kidney patients tested with autologous FCXM (n = 480). Improvements to FCXM and cell isolation methods significantly reduced the positive rate from 15.1{\%} to 5.3{\%}. Patients with native diseases considered 'immunological' (vasculitis,lupus,IgA nephropathy) had more positive autologous FCXM (OR = 3.36,p = 0.003) vs. patients with all other diseases. Patients who were tested using our updated method (n = 321) still showed that these immunological diseases were a significant predictor for positive autologous FCXM (OR = 4.79,p = 0.006). Interestingly,patients on peritoneal dialysis (PD) also had significantly more positive autologous FCXM than patients on hemodialysis or waiting for pre-emptive kidney transplants (OR = 3.27,p = 0.02). These findings were confirmed in patients who had false positive allogeneic FCXM. Twenty of 24 (83.3{\%}) patients with false positive allogeneic FCXM tested with updated method either had immunological diseases originally or were on PD. Our findings are helpful when interpreting an unexpected positive FCXM,especially for transplantation from deceased donors. View Publication

The vascular wall is a source of progenitor cells that are able to induce skeletal repair,primarily by paracrine mechanisms. Here,the paracrine role of extracellular vesicles (EVs) in bone healing was investigated. First,purified human perivascular stem cells (PSCs) were observed to induce mitogenic,pro-migratory,and pro-osteogenic effects on osteoprogenitor cells while in non-contact co-culture via elaboration of EVs. PSC-derived EVs shared mitogenic,pro-migratory,and pro-osteogenic properties of their parent cell. PSC-EV effects were dependent on surface-associated tetraspanins,as demonstrated by EV trypsinization,or neutralizing antibodies for CD9 or CD81. Moreover,shRNA knockdown in recipient cells demonstrated requirement for the CD9/CD81 binding partners IGSF8 and PTGFRN for EV bioactivity. Finally,PSC-EVs stimulated bone repair,and did so via stimulation of skeletal cell proliferation,migration,and osteodifferentiation. In sum,PSC-EVs mediate the same tissue repair effects of perivascular stem cells,and represent an 'off-the-shelf' alternative for bone tissue regeneration. View Publication