搜索结果: 'gmp t cell activator'

The endoplasmic reticular Ca(2+)-ATPase inhibitor,thapsigargin,was used to study the role of an increase in cytosolic free calcium concentration ([Ca2+]i) as a signal for the activation of thymocyte apoptosis. Treatment of rat thymocytes with thapsigargin resulted in an early sustained increase in [Ca2+]i followed by extensive DNA fragmentation. Agarose gel electrophoresis revealed that the pattern of DNA fragments was typical of endonuclease-mediated internucleosomal cleavage. In addition,confocal microscopy studies showed the formation of apoptotic nuclei in thapsigargin-treated thymocytes. The concentrations of thapsigargin required to induce DNA fragmentation and [Ca2+]i increase in thymocytes were identical and so were the kinetics of thapsigargin-induced DNA fragmentation and formation of apoptotic nuclei. The lowest concentration of thapsigargin needed to activate apoptosis was 1 nM. Thapsigargin-induced [Ca2+]i increase and thymocyte apoptosis were inhibited in cells incubated in nominally Ca(2+)-free medium or pretreated with the intracellular Ca2+ chelator,bis-(o-aminophenoxy)ethane-N,N,N',N'-tetraacetic acid/acetoxymethyl ester. Removal of extracellular free Ca2+ with 5 mM EGTA at different time points after thapsigargin addition revealed a time dependency of about 2 h for the sustained increase in [Ca2+]i to trigger apoptosis in thymocytes. Thus,we conclude that the signal provided by the thapsigargin-induced [Ca2+]i increase is sufficient to activate thymocyte apoptosis. View Publication

Motile cilia are cellular beating machines that play a critical role in mucociliary clearance,cerebrospinal fluid movement,and fertility. In the airways,hundreds of motile cilia present on the surface of a multiciliated epithelia cell beat coordinately to protect the epithelium from bacteria,viruses,and harmful particulates. During multiciliated cell differentiation,motile cilia are templated from basal bodies,each extending a basal foot-an appendage linking motile cilia together to ensure coordinated beating. Here,we demonstrate that among the many motile cilia of a multiciliated cell,a hybrid cilium with structural features of both primary and motile cilia is harbored. The hybrid cilium is conserved in mammalian multiciliated cells,originates from parental centrioles,and its cellular position is biased and dependent on ciliary beating. Furthermore,we show that the hybrid cilium emerges independently of other motile cilia and functions in regulating basal body alignment. View Publication

Regulation of the homeostasis of vascular endothelium is critical for the processes of vascular remodeling and angiogenesis under physiological and pathological conditions. Here we show that doxorubicin (Dox),a drug used in antitumor therapy,triggered a marked accumulation of p53 and induced CD95 gene expression and apoptosis in proliferating human umbilical vein endothelial cells (HUVECs). Transfection and site-directed mutagenesis experiments using the CD95 promoter fused to an intronic enhancer indicated the requirement for a p53 site for Dox-induced promoter activation. Furthermore,the p53 inhibitor pifithrin-alpha (PFT-alpha) blocked both promoter inducibility and protein up-regulation of CD95 in response to Dox. Up-regulated CD95 in Dox-treated cells was functional in eliciting apoptosis upon incubation of the cells with an agonistic CD95 antibody. However,Dox-mediated apoptosis was independent of CD95/CD95L interaction. The analysis of apoptosis in the presence of PFT-alpha and benzyloxycarbonyl-Val-Ala-dl-Asp-fluoromethylketone revealed that both p53 and caspase activation are required for Dox-mediated apoptosis of HUVECs. Finally,Dox triggered Bcl-2 down-regulation,cytochrome c release from mitochondria,and the activation of caspases 9 and 3,suggesting the involvement of a mitochondrially operated pathway of apoptosis. These results highlight the role of p53 in the response of primary endothelial cells to genotoxic drugs and may reveal a novel mechanism underlying the antitumoral properties of Dox,related to its ability to induce apoptosis in proliferating endothelial cells. View Publication

Protein arginine deiminase 4 (PAD4) is a transcriptional coregulator that catalyzes the calcium-dependent conversion of specific arginine residues in proteins to citrulline. Recently,we reported the synthesis and characterization of F-amidine,a potent and bioavailable irreversible inactivator of PAD4. Herein,we report our efforts to identify the steric and leaving group requirements for F-amidine-induced PAD4 inactivation,the structure of the PAD4-F-amidine x calcium complex,and in vivo studies with N-alpha-benzoyl-N5-(2-chloro-1-iminoethyl)-L-ornithine amide (Cl-amidine),a PAD4 inactivator with enhanced potency. The PAD4 inactivators described herein will be useful pharmacological probes in characterizing the incompletely defined physiological role(s) of this enzyme. In addition,they represent potential lead compounds for the treatment of rheumatoid arthritis because a growing body of evidence supports a role for PAD4 in the onset and progression of this chronic autoimmune disorder. View Publication

The generation of insulin-producing pancreatic $\beta$ cells from stem cells in vitro would provide an unprecedented cell source for drug discovery and cell transplantation therapy in diabetes. However,insulin-producing cells previously generated from human pluripotent stem cells (hPSC) lack many functional characteristics of bona fide $\beta$ cells. Here,we report a scalable differentiation protocol that can generate hundreds of millions of glucose-responsive $\beta$ cells from hPSC in vitro. These stem-cell-derived $\beta$ cells (SC-$\beta$) express markers found in mature $\beta$ cells,flux Ca(2+) in response to glucose,package insulin into secretory granules,and secrete quantities of insulin comparable to adult $\beta$ cells in response to multiple sequential glucose challenges in vitro. Furthermore,these cells secrete human insulin into the serum of mice shortly after transplantation in a glucose-regulated manner,and transplantation of these cells ameliorates hyperglycemia in diabetic mice. View Publication

Small molecules that promote the metabolic activity of the pyruvate kinase isoform PKM2,such as TEPP-46 and DASA-58,limit tumorigenesis and inflammation. To understand how these compounds alter T cell function,we assessed their therapeutic activity in a mouse model of T cell-mediated autoimmunity that mimics multiple sclerosis (MS). TH17 cells are believed to orchestrate MS pathology,in part,through the production of two proinflammatory cytokines: interleukin-17 (IL-17) and GM-CSF. We found that both TEPP-46 and DASA-58 suppressed the development of IL-17-producing TH17 cells but increased the generation of those producing GM-CSF. This switch redirected disease pathology from the spinal cord to the brain. In addition,we found that activation of PKM2 interfered with TGF-$\beta$1 signaling,which is necessary for the development of TH17 and regulatory T cells. Collectively,our data clarify the therapeutic potential of PKM2 activators in MS-like disease and how these agents alter T cell function. View Publication

Mifepristone is a potent antagonist of steroid hormone receptors such as glucocorticoid and progesterone receptors. We investigated the potential for mifepristone to act as an antiandrogen and compared it with partial androgen receptor (AR) agonists and antagonists,in particular bicalutamide. Mifepristone was an effective antiandrogen in vitro that inhibited transcription from three androgen-responsive promoters and blocked the agonist R1881 in a dose-dependent manner. Like bicalutamide,mifepristone also antagonized the action of androgen receptor with a (T877A) mutation. Mifepristone competed effectively with R1881 with a relative binding affinity comparable to that of cyproterone acetate,and much higher than that of hydroxyflutamide and bicalutamide in a binding assay. Mifepristone could effectively induce the binding of the herpes simplex viral protein 16/AR fusion protein to the hormone response elements in the murine mammary tumor virus-luciferase reporter. With either wild-type or T877A mutant AR,mifepristone alone was unable to induce any detectable interaction with coactivators transcriptional intermediary factor-2 or beta-catenin but could inhibit the R1881-induced binding of AR to transcriptional intermediary factor-2 and beta-catenin. Similarly,mifepristone could inhibit the R1881-induced N/C-terminal interaction in a dose-dependent manner even though mifepristone alone has no effect on the N/C-terminal interaction of AR. We found that mifepristone could induce a strong interaction between AR and corepressors nuclear receptor corepressor and silencing mediator for retinoid and thyroid hormone receptors in both transactivation and two-hybrid assays to a greater degree than hydroxyflutamide,cyproterone acetate,and bicalutamide. The AR-corepressor interaction was also seen in coimmunoprecipitation assays. Finally,mifepristone at high concentrations induced a low level of prostate-specific antigen expression in LNCaP and antagonized prostate-specific antigen expression induced by R1881. Mifepristone also antagonized R1881 action on the growth of LNCaP prostate cancer cells. View Publication

Type III interferon (interferon lambda [IFN-$\lambda$]) is known to be a potential immune modulator,but the mechanisms behind its immune-modulatory functions and its impact on plasmablast differentiation in humans remain unknown. Human B cells and their subtypes directly respond to IFN-$\lambda$. Using B cell transcriptome profiling,we investigate the immune-modulatory role of IFN-$\lambda$ in B cells. We find that IFN-$\lambda$-induced gene expression in B cells is steady,prolonged,and importantly,cell type specific. Furthermore,IFN-$\lambda$ enhances the mTORC1 (mammalian/mechanistic target of rapamycin complex 1) pathway in B cells activated by the B cell receptor (BCR/anti-IgM). Engagement of mTORC1 by BCR and IFN-$\lambda$ induces cell-cycle progress in B cells. Subsequently,IFN-$\lambda$ boosts the differentiation of naive B cells into plasmablasts upon activation,and the cells gain effector functions such as cytokine release (IL-6 and IL-10) and antibody production. Our study shows how IFN-$\lambda$ systematically boosts the differentiation of naive B cells into plasmablasts by enhancing the mTORC1 pathway and cell-cycle progression in activated B cells. View Publication

The human nasal epithelium is the primary site of exposure to influenza virus,the initiator of host responses to influenza and the resultant pathologies. Influenza virus may cause serious respiratory infection resulting in major complications,as well as severe impairment of the airways. Here,we elucidated the global transcriptomic changes during H3N2 infection of human nasal epithelial cells from multiple individuals. Using RNA sequencing,we characterized the differentially-expressed genes and pathways associated with changes occurring at the nasal epithelium following infection. We used in vitro differentiated human nasal epithelial cell culture model derived from seven different donors who had no concurrent history of viral infections. Statistical analysis highlighted strong transcriptomic signatures significantly associated with 24 and 48 h after infection,but not at the earlier 8-h time point. In particular,we found that the influenza infection induced in the nasal epithelium early and altered responses in interferon gamma signaling,B-cell signaling,apoptosis,necrosis,smooth muscle proliferation,and metabolic alterations. These molecular events initiated at the infected nasal epithelium may potentially adversely impact the airway,and thus the genes we identified could serve as potential diagnostic biomarkers or therapeutic targets for influenza infection and associated disease management. View Publication

Immunotherapy is innovating clinical cancer management. Nevertheless,only a small fraction of patient's benefit from current immunotherapies. To improve clinical management of cancer immunotherapy,it is critical to develop strategies for response monitoring and prediction. In this study,we describe inducible T-cell costimulator (ICOS) as a conserved mediator of immune response across multiple therapy strategies. ICOS expression was evaluated by flow cytometry,89Zr-DFO-ICOS mAb PET/CT imaging was performed on Lewis lung cancer models treated with different immunotherapy strategies,and the change in tumor volume was used as a read-out for therapeutic response. ImmunoPET imaging of ICOS enabled sensitive and specific detection of activated T cells and early benchmarking of immune response. A STING (stimulator of interferon genes) agonist was identified as a promising therapeutic approach in this manner. The STING agonist generated significantly stronger immune responses as measured by ICOS ImmunoPET and delayed tumor growth compared with programmed death-1 checkpoint blockade. More importantly,ICOS ImmunoPET enabled early and robust prediction of therapeutic response across multiple treatment regimens. These data show that ICOS is an indicator of T-cell-mediated immune response and suggests ICOS ImmunoPET as a promising strategy for monitoring,comparing,and predicting immunotherapy success in cancer. SIGNIFICANCE: ICOS ImmunoPET is a promising strategy to noninvasively predict and monitor immunotherapy response.See related commentary by Choyke,p. 2975. View Publication

Management of chronic kidney disease (CKD) remains a major challenge due limited therapeutic options to reverse fibrosis,which is a critical feature in CKD. Partial epithelial-to-mesenchymal transition (EMT) of tubular epithelial cells (TECs) is a key driver of fibrosis,and has become an important focus for kidney protection strategies. Blood platelets,a major source of circulating transforming growth factor beta (TGF-β),are implicated in pathogenesis of CKD,but their involvement in EMT and kidney fibrosis remains uncertain. Methods: We used two mouse models of renal fibrosis—diabetic kidney disease (DKD) and unilateral ureter obstruction (UUO)—to examine the connection between platelets,partial EMT,and fibrosis. Platelet inhibition or depletion was performed to assess EMT,cell cycle arrest,and fibrosis. In vitro,platelets were applied to TECs and kidney organoids. To determine the role of TGF-β signaling,we used TGF-βRI inhibitor. Expression of EMT,and fibrosis markers,as well as TGF-β1 signaling,were analyzed using western blot,reverse transcription quantitative PCR (RT-qPCR),enzyme-linked immunosorbent assay (ELISA),and immunostaining. Results: In both animal models,platelet inhibition or depletion resulted in reduced expression of cell cycle arrest marker p21,partial EMT and fibrosis. In vitro,activated platelets stimulated cell cycle arrest,EMT,and fibrosis in TECs and kidney organoids. Chronically injured TECs experience cell-cycle arrest which promote a paracrine EMT program in TECs,jointly leading to fibrosis. This platelet-mediated effect on cell cycle arrest and EMT was driven by TGF-β1 signaling,as selective inhibition of the TGF-β receptor rescued these dysfunctional phenotypes. Conclusions: Our study demonstrates that platelets activate the TGF-β1 pathway,leading to cell cycle arrest,EMT and renal fibrosis. These findings suggest that antiplatelet therapies may have potential renoprotective effects by protecting tubular homeostasis,attenuating partial EMT and fibrosis. View Publication

Antibody–drug conjugates (ADCs) represent a promising strategy in cancer therapy,enabling the targeted delivery of cytotoxic agents to tumor cells. In this study,we developed and characterized novel ADCs combining the anti-EGFR monoclonal therapeutic antibody Cetuximab (Cet) with two aminobisphosphonates (N-BPs) analogues of zoledronic acid (ZA): DC310 and the aminothiazole DC315. These conjugates aim to enhance antitumor efficacy of Cet in colorectal cancer (CRC) by both directly inhibiting tumor cell growth and activating Vδ2 T lymphocytes. We optimized the drug-antibody ratio (DAR),achieving significantly higher DARs compared to previously reported Cet-ZA conjugate,particularly with Cet-DC315 (DAR ≈ 23). Both ADCs retained selective EGFR binding in CRC cell lines and patient-derived organoids (PDO). Functionally,Cet-DC315 markedly inhibited proliferation of EGFR⁺ CRC cell lines in conventional cultures and 3D spheroids. Furthermore,Cet-DC-315 uniquely induced expansion and cytotoxic activation of Vδ2 T cells in co-cultures with CRC cell lines,PDO,and primary tumor samples. These findings suggest that ADCs incorporating novel N-BPs such as DC315 represent a potent approach for dual antitumor targeting through direct cytostatic effects and immune activation,offering a potential therapeutic advantage in the treatment of EGFR+ colorectal cancer. View Publication