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1.
Front Cell Dev Biol ; 12: 1356421, 2024.
Artigo em Inglês | MEDLINE | ID: mdl-38495618

RESUMO

Signal regulatory protein-α (SIRPα, SHPS-1, CD172a) expressed on myeloid cells transmits inhibitory signals when it engages its counter-receptor CD47 on an adjacent cell. Elevated CD47 expression on some cancer cells thereby serves as an innate immune checkpoint that limits phagocytic clearance of tumor cells by macrophages and antigen presentation to T cells. Antibodies and recombinant SIRPα constructs that block the CD47-SIRPα interaction on macrophages exhibit anti-tumor activities in mouse models and are in ongoing clinical trials for treating several human cancers. Based on prior evidence that engaging SIRPα can also alter CD47 signaling in some nonmalignant cells, we compared direct effects of recombinant SIRPα-Fc and a humanized CD47 antibody that inhibits CD47-SIRPα interaction (CC-90002) on CD47 signaling in cancer stem cells derived from the MDA-MB- 231 triple-negative breast carcinoma cell line. Treatment with SIRPα-Fc significantly increased the formation of mammospheres by breast cancer stem cells as compared to CC-90002 treatment or controls. Furthermore, SIRPα-Fc treatment upregulated mRNA and protein expression of ALDH1 and altered the expression of genes involved in epithelial/mesenchymal transition pathways that are associated with a poor prognosis and enhanced metastatic activity. This indicates that SIRPα-Fc has CD47-mediated agonist activities in breast cancer stem cells affecting proliferation and metastasis pathways that differ from those of CC-90002. This SIRPα-induced CD47 signaling in breast carcinoma cells may limit the efficacy of SIRPα decoy therapeutics intended to stimulate innate antitumor immune responses.

2.
Mol Carcinog ; 2024 Feb 27.
Artigo em Inglês | MEDLINE | ID: mdl-38411275

RESUMO

Homologous recombination (HR) and poly ADP-ribosylation are partially redundant pathways for the repair of DNA damage in normal and cancer cells. In cell lines that are deficient in HR, inhibition of poly (ADP-ribose) polymerase (poly (ADP-ribose) polymerase [PARP]1/2) is a proven target with several PARP inhibitors (PARPis) currently in clinical use. Resistance to PARPi often develops, usually involving genetic alterations in DNA repair signaling cascades, but also metabolic rewiring particularly in HR-proficient cells. We surmised that alterations in metabolic pathways by cancer drugs such as Olaparib might be involved in the development of resistance to drug therapy. To test this hypothesis, we conducted a metabolism-focused clustered regularly interspaced short palindromic repeats knockout screen to identify genes that undergo alterations during the treatment of tumor cells with PARPis. Of about 3000 genes in the screen, our data revealed that mitochondrial pyruvate carrier 1 (MPC1) is an essential factor in desensitizing nonsmall cell lung cancer (NSCLC) lung cancer lines to PARP inhibition. In contrast to NSCLC lung cancer cells, triple-negative breast cancer cells do not exhibit such desensitization following MPC1 loss and reprogram the tricarboxylic acid cycle and oxidative phosphorylation pathways to overcome PARPi treatment. Our findings unveil a previously unknown synergistic response between MPC1 loss and PARP inhibition in lung cancer cells.

3.
Angew Chem Int Ed Engl ; 63(9): e202316772, 2024 Feb 26.
Artigo em Inglês | MEDLINE | ID: mdl-38204294

RESUMO

Renewable electricity driven electrocatalytic CO2 reduction reaction (CO2 RR) is a promising solution to carbon neutralization, which mainly generate simple carbon products. It is of great importance to produce more valuable C-N chemicals from CO2 and nitrogen species. However, it is challenging to co-reduce CO2 and NO3 - /NO2 - to generate aldoxime an important intermediate in the electrocatalytic C-N coupling process. Herein, we report the successful electrochemical conversion of CO2 and NO2 - to acetamide for the first time over copper catalysts under alkaline condition through a gas diffusion electrode. Operando spectroelectrochemical characterizations and DFT calculations, suggest acetaldehyde and hydroxylamine identified as key intermediates undergo a nucleophilic addition reaction to produce acetaldoxime, which is then dehydrated to acetonitrile and followed by hydrolysis to give acetamide under highly local alkaline environment and electric field. Moreover, the above mechanism was successfully extended to the formation of phenylacetamide. This study provides a new strategy to synthesize highly valued amides from CO2 and wastewater.

4.
mBio ; 15(2): e0299823, 2024 Feb 14.
Artigo em Inglês | MEDLINE | ID: mdl-38170993

RESUMO

Cancers associated with the oncogenic gammaherpesviruses, Epstein-Barr virus and Kaposi sarcoma herpesvirus, are notable for their constitutive activation of the transcription factor signal transducer and activator of transcription 3 (STAT3). To better understand the role of STAT3 during gammaherpesvirus latency and the B cell response to infection, we used the model pathogen murine gammaherpesvirus 68 (MHV68). Genetic deletion of STAT3 in B cells of CD19cre/+Stat3f/f mice reduced peak MHV68 latency approximately sevenfold. However, infected CD19cre/+Stat3f/f mice exhibited disordered germinal centers and heightened virus-specific CD8 T cell responses compared to wild-type (WT) littermates. To circumvent the systemic immune alterations observed in the B cell-STAT3 knockout mice and more directly evaluate intrinsic roles for STAT3, we generated mixed bone marrow chimeric mice consisting of WT and STAT3 knockout B cells. We discovered a dramatic reduction in latency in STAT3 knockout B cells compared to their WT B cell counterparts in the same lymphoid organ. RNA sequencing of sorted germinal center B cells revealed that MHV68 infection shifts the gene signature toward proliferation and away from type I and type II IFN responses. Loss of STAT3 largely reversed the virus-driven transcriptional shift without impacting the viral gene expression program. STAT3 promoted B cell processes of the germinal center, including IL-21-stimulated downregulation of surface CD23 on B cells infected with MHV68 or EBV. Together, our data provide mechanistic insights into the role of STAT3 as a latency determinant in B cells for oncogenic gammaherpesviruses.IMPORTANCEThere are no directed therapies to the latency program of the human gammaherpesviruses, Epstein-Barr virus and Kaposi sarcoma herpesvirus. Activated host factor signal transducer and activator of transcription 3 (STAT3) is a hallmark of cancers caused by these viruses. We applied the murine gammaherpesvirus pathogen system to explore STAT3 function upon primary B cell infection in the host. Since STAT3 deletion in all CD19+ B cells of infected mice led to altered B and T cell responses, we generated chimeric mice with both normal and STAT3-deleted B cells. B cells lacking STAT3 failed to support virus latency compared to normal B cells from the same infected animal. Loss of STAT3 impaired B cell proliferation and differentiation and led to a striking upregulation of interferon-stimulated genes. These findings expand our understanding of STAT3-dependent processes that are key to its function as a pro-viral latency determinant for oncogenic gammaherpesviruses in B cells and may provide novel therapeutic targets.


Assuntos
Infecções por Vírus Epstein-Barr , Gammaherpesvirinae , Infecções por Herpesviridae , Herpesvirus Humano 8 , Rhadinovirus , Sarcoma de Kaposi , Animais , Humanos , Camundongos , Gammaherpesvirinae/genética , Herpesvirus Humano 4/genética , Herpesvirus Humano 4/metabolismo , Herpesvirus Humano 8/metabolismo , Camundongos Endogâmicos C57BL , Rhadinovirus/genética , Fator de Transcrição STAT3/genética , Fator de Transcrição STAT3/metabolismo , Latência Viral/genética
5.
bioRxiv ; 2023 Sep 28.
Artigo em Inglês | MEDLINE | ID: mdl-37808833

RESUMO

Extramedullary erythropoiesis is not expected in healthy adult mice, but erythropoietic gene expression was elevated in lineage-depleted spleen cells from cd47-/- mice. Expression of several genes associated with early stages of erythropoiesis was elevated in mice lacking CD47 or its signaling ligand thrombospondin-1, consistent with previous evidence that this signaling pathway inhibits expression of multipotent stem cell transcription factors in spleen. In contrast, cells expressing markers of committed erythroid progenitors were more abundant in cd47-/- spleens but significantly depleted in thbs1-/- spleens. Single cell transcriptome and flow cytometry analyses indicated that loss of CD47 is associated with accumulation and increased proliferation in spleen of Ter119-CD34+ progenitors and Ter119+CD34- committed erythroid progenitors with elevated mRNA expression of Kit, Ermap, and Tfrc, Induction of committed erythroid precursors is consistent with the known function of CD47 to limit the phagocytic removal of aged erythrocytes. Conversely, loss of thrombospondin-1 delays the turnover of aged red blood cells, which may account for the suppression of committed erythroid precursors in thbs1-/- spleens relative to basal levels in wild type mice. In addition to defining a role for CD47 to limit extramedullary erythropoiesis, these studies reveal a thrombospondin-1-dependent basal level of extramedullary erythropoiesis in adult mouse spleen.

7.
J Am Chem Soc ; 145(39): 21491-21501, 2023 Oct 04.
Artigo em Inglês | MEDLINE | ID: mdl-37733833

RESUMO

Electrochemical nitrate (NO3-) reduction in aqueous media provides a useful approach for ammonia (NH3) synthesis. While efforts are focused on developing catalysts, the local microenvironment surrounding the catalyst centers is of great importance for controlling electrocatalytic performance. Here, we demonstrate that a self-assembled molecular iron catalyst integrated in a free-standing conductive hydrogel is capable of selective production of NH3 from NO3- at efficiencies approaching unity. With the electrocatalytic hydrogel, the NH3 selectivity is consistently high under a range of negative biases, which results from the hydrophobicity increase of the polycarbazole-based electrode substrate. In mildly acidic media, proton reduction is suppressed by electro-dewetting of the hydrogel electrode, enhancing the selectivity of NO3- reduction. The electrocatalytic hydrogel is capable of continuous production of NH3 for at least 100 h with NH3 selectivity of ∼89 to 98% at high current densities. Our results highlight the role of constructing an internal hydrophobic surface for electrocatalysts in controlling selectivity in aqueous media.

8.
Chem Rev ; 123(17): 10530-10583, 2023 Sep 13.
Artigo em Inglês | MEDLINE | ID: mdl-37589482

RESUMO

Electrosynthesis of value-added chemicals, directly from CO2, could foster achievement of carbon neutral through an alternative electrical approach to the energy-intensive thermochemical industry for carbon utilization. Progress in this area, based on electrogeneration of multicarbon products through CO2 electroreduction, however, lags far behind that for C1 products. Reaction routes are complicated and kinetics are slow with scale up to the high levels required for commercialization, posing significant problems. In this review, we identify and summarize state-of-art progress in multicarbon synthesis with a multiscale perspective and discuss current hurdles to be resolved for multicarbon generation from CO2 reduction including atomistic mechanisms, nanoscale electrocatalysts, microscale electrodes, and macroscale electrolyzers with guidelines for future research. The review ends with a cross-scale perspective that links discrepancies between different approaches with extensions to performance and stability issues that arise from extensions to an industrial environment.

9.
J Clin Invest ; 133(18)2023 09 15.
Artigo em Inglês | MEDLINE | ID: mdl-37471141

RESUMO

Glucocorticoids are steroid hormones with potent immunosuppressive properties. Their primary source is the adrenals, where they are generated via de novo synthesis from cholesterol. In addition, many tissues have a recycling pathway in which glucocorticoids are regenerated from inactive metabolites by the enzyme 11ß-hydroxysteroid dehydrogenase type 1 (11ß-HSD1, encoded by Hsd11b1). Here, we find that multiple tumor types express Hsd11b1 and produce active glucocorticoids. Genetic ablation of Hsd11b1 in such cells had no effect on in vitro growth, but reduced in vivo tumor progression, which corresponded with increased frequencies of CD8+ tumor-infiltrating lymphocytes (TILs) expressing activation markers and producing effector cytokines. Tumor-derived glucocorticoids were found to promote signatures of Treg activation and suppress signatures of conventional T cell activation in tumor-infiltrating Tregs. Indeed, CD8+ T cell activation was restored and tumor growth reduced in mice with Treg-specific glucocorticoid receptor deficiency. Importantly, pharmacologic inhibition of 11ß-HSD1 reduced tumor growth to the same degree as gene knockout and rendered immunotherapy-resistant tumors susceptible to PD-1 blockade. Given that HSD11B1 expression is upregulated in many human tumors and that inhibition of 11ß-HSD1 is well tolerated in clinical studies, these data suggest that targeting 11ß-HSD1 may be a beneficial adjunct in cancer therapy.


Assuntos
Glucocorticoides , Neoplasias , Camundongos , Humanos , Animais , Glucocorticoides/farmacologia , Glucocorticoides/metabolismo , 11-beta-Hidroxiesteroide Desidrogenase Tipo 1/genética , 11-beta-Hidroxiesteroide Desidrogenase Tipo 1/metabolismo , Receptores de Glucocorticoides/genética , Técnicas de Inativação de Genes
10.
J Pathol ; 260(3): 276-288, 2023 07.
Artigo em Inglês | MEDLINE | ID: mdl-37185821

RESUMO

The effect of cytokines on non-traditional immunological targets under conditions of chronic inflammation is an ongoing subject of study. Fatigue is a symptom often associated with autoimmune diseases. Chronic inflammatory response and activated cell-mediated immunity are associated with cardiovascular myopathies which can be driven by muscle weakness and fatigue. Thus, we hypothesize that immune dysfunction-driven changes in myocyte mitochondria may play a critical role in fatigue-related pathogenesis. We show that persistent low-level expression of IFN-γ in designated IFN-γ AU-Rich Element deletion mice (ARE mice) under androgen exposure resulted in mitochondrial and metabolic deficiencies in myocytes from male or castrated ARE mice. Most notably, echocardiography unveiled that low ejection fraction in the left ventricle post-stress correlated with mitochondrial deficiencies, explaining how heart function decreases under stress. We report that inefficiencies and structural changes in mitochondria, with changes to expression of mitochondrial genes, are linked to male-biased fatigue and acute cardiomyopathy under stress. Our work highlights how male androgen hormone backgrounds and active autoimmunity reduce mitochondrial function and the ability to cope with stress and how pharmacological blockade of stress signal protects heart function. These studies provide new insight into the diverse actions of IFN-γ in fatigue, energy metabolism, and autoimmunity. © 2023 The Pathological Society of Great Britain and Ireland. This article has been contributed to by U.S. Government employees and their work is in the public domain in the USA.


Assuntos
Androgênios , Interferon gama , Animais , Masculino , Camundongos , Androgênios/metabolismo , Citocinas/metabolismo , Inflamação/metabolismo , Mitocôndrias/metabolismo , Células Musculares/metabolismo
11.
bioRxiv ; 2023 Mar 22.
Artigo em Inglês | MEDLINE | ID: mdl-36993230

RESUMO

Cancers associated with the oncogenic gammaherpesviruses, Epstein-Barr virus and Kaposi sarcoma herpesvirus, are notable for their constitutive activation of the transcription factor STAT3. To better understand the role of STAT3 during gammaherpesvirus latency and immune control, we utilized murine gammaherpesvirus 68 (MHV68) infection. Genetic deletion of STAT3 in B cells of CD19cre/+Stat3f/f mice reduced peak latency approximately 7-fold. However, infected CD19cre/+Stat3f/f mice exhibited disordered germinal centers and heightened virus-specific CD8 T cell responses compared to WT littermates. To circumvent the systemic immune alterations observed in the B cell-STAT3 knockout mice and more directly evaluate intrinsic roles for STAT3, we generated mixed bone marrow chimeras consisting of WT and STAT3-knockout B cells. Using a competitive model of infection, we discovered a dramatic reduction in latency in STAT3-knockout B cells compared to their WT B cell counterparts in the same lymphoid organ. RNA sequencing of sorted germinal center B cells revealed that STAT3 promotes proliferation and B cell processes of the germinal center but does not directly regulate viral gene expression. Last, this analysis uncovered a STAT3-dependent role for dampening type I IFN responses in newly infected B cells. Together, our data provide mechanistic insight into the role of STAT3 as a latency determinant in B cells for oncogenic gammaherpesviruses.

12.
ACS Nano ; 17(5): 4922-4932, 2023 Mar 14.
Artigo em Inglês | MEDLINE | ID: mdl-36800562

RESUMO

Photoreduction of CO2 is a promising strategy to synthesize value-added fuels or chemicals and realize carbon neutralization. Noncopper catalysts are seldom reported to generate C2 products, and the selectivity over these catalysts is low. Here, we design rich-interface, heterostructured In2O3/InP (r-In2O3/InP) for highly competitive photocatalytic CO2-to-CH3COOH conversion with a productivity of 96.7 µmol g-1 and selectivity > 96% along with water oxidation to O2 in pure water (no sacrificial agent) under visible light irradiation. The hard X-ray absorption near-edge structure (XANES) shows that the formation of r-In2O3/InP with the isogenesis cation adjusts the coordination environment via interface engineering and forms O-In-P polarized sites at the interface. In situ FT-IR and Raman spectra identify the key intermediates of OCCO* for acetate production with high selectivity. Density functional theory (DFT) calculations reveal that r-In2O3/InP with rich O-In-P polarized sites promotes C-C coupling to form C2 products because of the imbalanced adsorption energies of two carbon atoms. This work reports an interesting indium-based photocatalyst for selective CO2 photoreduction to acetate under strict solution and irradiation conditions and provides significant insights into fabricating interfacial polarization sites to promote the process.

13.
Int J Mol Sci ; 24(3)2023 Jan 30.
Artigo em Inglês | MEDLINE | ID: mdl-36768931

RESUMO

Elevated expression of CD47 in some cancers is associated with poor survival related to its function as an innate immune checkpoint when expressed on tumor cells. In contrast, elevated CD47 expression in cutaneous melanomas is associated with improved survival. Previous studies implicated protective functions of CD47 expressed by immune cells in the melanoma tumor microenvironment. RNA sequencing analysis of responses induced by CD3 and CD28 engagement on wild type and CD47-deficient Jurkat T lymphoblast cells identified additional regulators of T cell function that were also CD47-dependent in mouse CD8 T cells. MYCN mRNA expression was upregulated in CD47-deficient cells but downregulated in CD47-deficient cells following activation. CD47 also regulated alternative splicing that produces two N-MYC isoforms. The CD47 ligand thrombospondin-1 inhibited expression of these MYCN mRNA isoforms, as well as induction of the oncogenic decoy MYCN opposite strand (MYCNOS) RNA during T cell activation. Analysis of mRNA expression data for melanomas in The Cancer Genome Atlas identified a significant coexpression of MYCN with CD47 and known regulators of CD8 T cell function. Thrombospondin-1 inhibited the induction of TIGIT, CD40LG, and MCL1 mRNAs following T cell activation in vitro. Increased mRNA expression of these T cell transcripts and MYCN in melanomas was associated with improved overall survival.


Assuntos
Antígeno CD47 , Melanoma , Camundongos , Animais , Antígeno CD47/metabolismo , Proteína Proto-Oncogênica N-Myc/genética , Linfócitos T CD8-Positivos , Expressão Gênica , Melanoma/genética , RNA Mensageiro/genética , Trombospondinas/genética , Microambiente Tumoral
14.
Proc Natl Acad Sci U S A ; 120(4): e2214175120, 2023 Jan 24.
Artigo em Inglês | MEDLINE | ID: mdl-36649419

RESUMO

Copper is distinctive in electrocatalyzing reduction of CO2 into various energy-dense forms, but it often suffers from limited product selectivity including ethanol in competition with ethylene. Here, we describe systematically designed, bimetallic electrocatalysts based on copper/gold heterojunctions with a faradaic efficiency toward ethanol of 60% at currents in excess of 500 mA cm-2. In the modified catalyst, the ratio of ethanol to ethylene is enhanced by a factor of 200 compared to copper catalysts. Analysis by ATR-IR measurements under operating conditions, and by computational simulations, suggests that reduction of CO2 at the copper/gold heterojunction is dominated by generation of the intermediate OCCOH*. The latter is a key contributor in the overall, asymmetrical electrohydrogenation of CO2 giving ethanol rather than ethylene.

15.
J Chem Phys ; 157(24): 244703, 2022 Dec 28.
Artigo em Inglês | MEDLINE | ID: mdl-36586990

RESUMO

A kinetic framework for the ultrafast photophysics of tris(2,2-bipyridine)ruthenium(II) phosphonated and methyl-phosphonated derivatives is used as a basis for modeling charge injection by ruthenium dyes into a semiconductor substrate. By including the effects of light scattering, dye diffusion, and adsorption kinetics during sample preparation and the optical response of oxidized dyes, quantitative agreement with multiple transient absorption datasets is achieved on timescales spanning femtoseconds to nanoseconds. In particular, quantitative agreement with important spectroscopic handles-the decay of an excited state absorption signal component associated with charge injection in the UV region of the spectrum and the dynamical redshift of a ∼500 nm isosbestic point-validates our kinetic model. Pseudo-first-order rate coefficients for charge injection are estimated in this work, with an order of magnitude ranging from 1011 to 1012 s-1. The model makes the minimalist assumption that all excited states of a particular dye have the same charge injection coefficient, an assumption that would benefit from additional theoretical and experimental exploration. We have adapted this kinetic model to predict charge injection under continuous solar irradiation and find that as many as 68 electron transfer events per dye per second take place, significantly more than prior estimates in the literature.

16.
Sci Bull (Beijing) ; 67(4): 398-407, 2022 02 26.
Artigo em Inglês | MEDLINE | ID: mdl-36546092

RESUMO

A unique "integrated hard-templating strategy" is described for facile synthesis of a carbonaceous material with a novel three-dimensional (3D) branched hollow architecture. A set of steps, including template formation, surface coating and template removal, all occur in a spontaneous and orderly manner in the one-pot hydrothermal process. Investigations on structural evolution during the process reveal that pre-synthesized zeolitic imidazolate framework-8 (ZIF-8) nanoparticles are first dissociated and then self-assembled into 3D branched superstructures of ZnO as templates. Initial self-assembly is followed by coating of the glucose-derived carbonaceous materials and etching of interior ZnO by organic acids released in situ by hydrolysis of glucose. The 3D-branched hollow architecture is shown to greatly enhance supercapacitor performance. The research described here provides guidance into the development of strategies for complex hollow carbonaceous architectures for a variety of potential applications.


Assuntos
Nanopartículas , Zeolitas , Óxido de Zinco , Glucose , Hidrólise
17.
Carcinogenesis ; 43(12): 1149-1161, 2022 12 31.
Artigo em Inglês | MEDLINE | ID: mdl-36306264

RESUMO

Environmental and molecular carcinogenesis are linked by the discovery that chemical carcinogen induced-mutations in the Hras or Kras genes drives tumor development in mouse skin. Importantly, enhanced expression or allele amplification of the mutant Ras gene contributes to selection of initiated cells, tumor persistence, and progression. To explore the consequences of Ras oncogene signal strength, primary keratinocytes were isolated and cultured from the LSL-HrasG12D and LSL-KrasG12D C57BL/6J mouse models and the mutant allele was activated by adeno-Cre recombinase. Keratinocytes expressing one (H) or two (HH) mutant alleles of HrasG12D, one KrasG12D allele (K), or one of each (HK) were studied. All combinations of activated Ras alleles stimulated proliferation and drove transformation marker expression, but only HH and HK formed tumors. HH, HK, and K sustained long-term keratinocyte growth in vitro, while H and WT could not. RNA-Seq yielded two distinct gene expression profiles; HH, HK, and K formed one cluster while H clustered with WT. Weak MAPK activation was seen in H keratinocytes but treatment with a BRAF inhibitor enhanced MAPK signaling and facilitated tumor formation. K keratinocytes became tumorigenic when they were isolated from mice where the LSL-KrasG12D allele was backcrossed from the C57BL/6 onto the FVB/N background. All tumorigenic keratinocytes but not the non-tumorigenic precursors shared a common remodeling of matrisomal gene expression that is associated with tumor formation. Thus, RAS oncogene signal strength determines cell-autonomous changes in initiated cells that are critical for their tumor-forming potential.


Assuntos
Transformação Celular Neoplásica , Genes ras , Camundongos , Animais , Transformação Celular Neoplásica/patologia , Camundongos Endogâmicos C57BL , Queratinócitos/patologia , Carcinogênese/patologia , Expressão Gênica
18.
Oncoimmunology ; 11(1): 2111909, 2022.
Artigo em Inglês | MEDLINE | ID: mdl-36105746

RESUMO

CD47 has established roles in the immune system for regulating macrophage phagocytosis and lymphocyte activation, with growing evidence of its cell-intrinsic regulatory roles in natural killer and CD8+ T cells. CD47 limits antigen-dependent cytotoxic activities of human and murine CD8+ T cells, but its role in T cell activation kinetics remains unclear. Using in vitro and in vivo models, we show here that CD47 differentially regulates CD8+ T cell responses to short- versus long-term activation. Although CD47 was not required for T cell development in mice and early activation in vitro, short-term stimuli elevated pathogen-reactive gene expression and enhanced proliferation and the effector phenotypes of Cd47-deficient relative to Cd47-sufficient CD8+ T cells. In contrast, persistent TCR stimulation limited the effector phenotypes of Cd47 -/- CD8+ T cells and enhanced their apoptosis signature. CD8+ T cell expansion and activation in vivo induced by acute lymphocytic choriomeningitis virus (LCMV) infection did not differ in the absence of CD47. However, the frequency and effector phenotypes of Cd47-/- CD8+ T cells were constrained in chronic LCMV-infected as well as in mice bearing B16 melanoma tumors. Therefore, CD47 regulates CD8+ T cell activation, proliferation, and fitness in a context-dependent manner.


Assuntos
Ativação Linfocitária , Coriomeningite Linfocítica , Animais , Antígeno CD47/genética , Linfócitos T CD8-Positivos , Humanos , Camundongos , Camundongos Endogâmicos C57BL , Camundongos Knockout
19.
Genome Res ; 32(7): 1298-1314, 2022 07.
Artigo em Inglês | MEDLINE | ID: mdl-35728967

RESUMO

The retrotransposon LINE-1 (L1) is central to the recent evolutionary history of the human genome and continues to drive genetic diversity and germline pathogenesis. However, the spatiotemporal extent and biological significance of somatic L1 activity are poorly defined and are virtually unexplored in other primates. From a single L1 lineage active at the divergence of apes and Old World monkeys, successive L1 subfamilies have emerged in each descendant primate germline. As revealed by case studies, the presently active human L1 subfamily can also mobilize during embryonic and brain development in vivo. It is unknown whether nonhuman primate L1s can similarly generate somatic insertions in the brain. Here we applied approximately 40× single-cell whole-genome sequencing (scWGS), as well as retrotransposon capture sequencing (RC-seq), to 20 hippocampal neurons from two rhesus macaques (Macaca mulatta). In one animal, we detected and PCR-validated a somatic L1 insertion that generated target site duplications, carried a short 5' transduction, and was present in ∼7% of hippocampal neurons but absent from cerebellum and nonbrain tissues. The corresponding donor L1 allele was exceptionally mobile in vitro and was embedded in PRDM4, a gene expressed throughout development and in neural stem cells. Nanopore long-read methylome and RNA-seq transcriptome analyses indicated young retrotransposon subfamily activation in the early embryo, followed by repression in adult tissues. These data highlight endogenous macaque L1 retrotransposition potential, provide prototypical evidence of L1-mediated somatic mosaicism in a nonhuman primate, and allude to L1 mobility in the brain over the past 30 million years of human evolution.


Assuntos
Encéfalo , Elementos Nucleotídeos Longos e Dispersos , Retroelementos , Animais , Proteínas de Ligação a DNA/genética , Macaca mulatta/genética , Neurônios , Retroelementos/genética , Fatores de Transcrição/genética
20.
Sci Rep ; 12(1): 7215, 2022 May 04.
Artigo em Inglês | MEDLINE | ID: mdl-35508647

RESUMO

The first analytical evaluation of a free-hinged-hinged-hinged-free beam proposed for use as the primary sensing element of a new gravity gradiometer is presented. Results of the evaluation obtained in quadratures are applied to the beam's structure, including locating the hinges that form the beam's boundary conditions allowing only free rotations around its nodal axes. These are deliberately chosen to minimize the beam's symmetric free ends deflections under the uniform body loading of gravity while simultaneously permitting the beam's maximum possible mirror-symmetric free ends deflections owing to a gravity gradient distributed along its length. The flexible triple-hinged beam deformation from its nominal unloaded geometry is naturally elastically coupled throughout, including free ends, allowing synchronized mechanical displacement measurements at any deflection point. Some methods of manufacturing such sensing elements and their respective error mechanisms are also discussed and presented for the first time.

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