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Understanding cellular force transmission dynamics is crucial in mechanobiology. We developed the DNA-based ForceChrono probe to measure force magnitude, duration, and loading rates at the single-molecule level within living cells. The ForceChrono probe circumvents the limitations of in vitro single-molecule force spectroscopy by enabling direct measurements within the dynamic cellular environment. Our findings reveal integrin force loading rates of 0.5-2 pN/s and durations ranging from tens of seconds in nascent adhesions to approximately 100 s in mature focal adhesions. The probe's robust and reversible design allows for continuous monitoring of these dynamic changes as cells undergo morphological transformations. Additionally, by analyzing how mutations, deletions, or pharmacological interventions affect these parameters, we can deduce the functional roles of specific proteins or domains in cellular mechanotransduction. The ForceChrono probe provides detailed insights into the dynamics of mechanical forces, advancing our understanding of cellular mechanics and the molecular mechanisms of mechanotransduction.
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Mecanotransducción Celular , Imagen Individual de Molécula , Animales , Humanos , Ratones , Fenómenos Biomecánicos , Adhesión Celular , ADN/química , ADN/metabolismo , Adhesiones Focales/metabolismo , Integrinas/metabolismo , Microscopía de Fuerza Atómica/métodos , Imagen Individual de Molécula/métodos , Línea Celular , Supervivencia Celular , Emparejamiento Base , CalibraciónRESUMEN
The identification of CD4+ T cells localizing to B cell follicles has revolutionized the knowledge of how humoral immunity is generated. Follicular helper T (TFH) cells support germinal center (GC) formation and regulate clonal selection and differentiation of memory and antibody-secreting B cells, thus controlling antibody affinity maturation and memory. TFH cells are essential in sustaining protective antibody responses necessary for pathogen clearance in infection and vaccine-mediated protection. Conversely, aberrant and excessive TFH cell responses mediate and sustain pathogenic antibodies to autoantigens, alloantigens, and allergens, facilitate lymphomagenesis, and even harbor viral reservoirs. TFH cell generation and function are determined by T cell antigen receptor (TCR), costimulation, and cytokine signals, together with specific metabolic and survival mechanisms. Such regulation is crucial to understanding disease pathogenesis and informing the development of emerging therapies for disease or novel approaches to boost vaccine efficacy.
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Centro Germinal , Linfocitos T Colaboradores-Inductores , Formación de Anticuerpos , Linfocitos B , Diferenciación Celular , Humanos , VacunaciónRESUMEN
The presence of DNA in the cytoplasm is normally a sign of microbial infections and is quickly detected by cyclic GMP-AMP synthase (cGAS) to elicit anti-infection immune responses. However, chronic activation of cGAS by self-DNA leads to severe autoimmune diseases for which no effective treatment is available yet. Here we report that acetylation inhibits cGAS activation and that the enforced acetylation of cGAS by aspirin robustly suppresses self-DNA-induced autoimmunity. We find that cGAS acetylation on either Lys384, Lys394, or Lys414 contributes to keeping cGAS inactive. cGAS is deacetylated in response to DNA challenges. Importantly, we show that aspirin can directly acetylate cGAS and efficiently inhibit cGAS-mediated immune responses. Finally, we demonstrate that aspirin can effectively suppress self-DNA-induced autoimmunity in Aicardi-Goutières syndrome (AGS) patient cells and in an AGS mouse model. Thus, our study reveals that acetylation contributes to cGAS activity regulation and provides a potential therapy for treating DNA-mediated autoimmune diseases.
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ADN/inmunología , Nucleotidiltransferasas/metabolismo , Autotolerancia/inmunología , Acetilación , Secuencia de Aminoácidos , Animales , Aspirina/farmacología , Enfermedades Autoinmunes/genética , Enfermedades Autoinmunes/inmunología , Enfermedades Autoinmunes/metabolismo , Enfermedades Autoinmunes del Sistema Nervioso/genética , Enfermedades Autoinmunes del Sistema Nervioso/inmunología , Enfermedades Autoinmunes del Sistema Nervioso/metabolismo , Autoinmunidad , Línea Celular , ADN/genética , ADN/metabolismo , Modelos Animales de Enfermedad , Exodesoxirribonucleasas/metabolismo , Células HEK293 , Células HeLa , Humanos , Ratones , Ratones Endogámicos C57BL , Modelos Moleculares , Mutación , Malformaciones del Sistema Nervioso/genética , Malformaciones del Sistema Nervioso/inmunología , Malformaciones del Sistema Nervioso/metabolismo , Nucleotidiltransferasas/antagonistas & inhibidores , Nucleotidiltransferasas/química , Nucleotidiltransferasas/genética , Células THP-1RESUMEN
Follicular helper T (TFH) cells are a specialized subset of CD4+ T cells that essentially support germinal center responses where high-affinity and long-lived humoral immunity is generated. The regulation of TFH cell survival remains unclear. Here we report that TFH cells show intensified lipid peroxidation and altered mitochondrial morphology, resembling the features of ferroptosis, a form of programmed cell death that is driven by iron-dependent accumulation of lipid peroxidation. Glutathione peroxidase 4 (GPX4) is the major lipid peroxidation scavenger and is necessary for TFH cell survival. The deletion of GPX4 in T cells selectively abrogated TFH cells and germinal center responses in immunized mice. Selenium supplementation enhanced GPX4 expression in T cells, increased TFH cell numbers and promoted antibody responses in immunized mice and young adults after influenza vaccination. Our findings reveal the central role of the selenium-GPX4-ferroptosis axis in regulating TFH homeostasis, which can be targeted to enhance TFH cell function in infection and following vaccination.
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Ferroptosis/fisiología , Fosfolípido Hidroperóxido Glutatión Peroxidasa/metabolismo , Selenio/farmacología , Células T Auxiliares Foliculares/fisiología , Adolescente , Adulto , Animales , Supervivencia Celular/inmunología , Niño , Femenino , Centro Germinal/citología , Centro Germinal/inmunología , Homeostasis/efectos de los fármacos , Homeostasis/genética , Humanos , Inmunidad Humoral/inmunología , Vacunas contra la Influenza/inmunología , Peroxidación de Lípido/fisiología , Masculino , Ratones , Ratones Endogámicos C57BL , Ratones Noqueados , Mitocondrias/fisiología , Ovalbúmina , Células T Auxiliares Foliculares/inmunología , Vacunación , Adulto JovenRESUMEN
Cyclic GMP-AMP synthase (cGAS) is a key sensor responsible for cytosolic DNA detection. Here we report that GTPase-activating protein SH3 domain-binding protein 1 (G3BP1) is critical for DNA sensing and efficient activation of cGAS. G3BP1 enhanced DNA binding of cGAS by promoting the formation of large cGAS complexes. G3BP1 deficiency led to inefficient DNA binding by cGAS and inhibited cGAS-dependent interferon (IFN) production. The G3BP1 inhibitor epigallocatechin gallate (EGCG) disrupted existing G3BP1-cGAS complexes and inhibited DNA-triggered cGAS activation, thereby blocking DNA-induced IFN production both in vivo and in vitro. EGCG administration blunted self DNA-induced autoinflammatory responses in an Aicardi-Goutières syndrome (AGS) mouse model and reduced IFN-stimulated gene expression in cells from a patient with AGS. Thus, our study reveals that G3BP1 physically interacts with and primes cGAS for efficient activation. Furthermore, EGCG-mediated inhibition of G3BP1 provides a potential treatment for cGAS-related autoimmune diseases.
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Enfermedades Autoinmunes del Sistema Nervioso/metabolismo , ADN Helicasas/metabolismo , Complejos Multiproteicos/metabolismo , Malformaciones del Sistema Nervioso/metabolismo , Nucleotidiltransferasas/metabolismo , Proteínas de Unión a Poli-ADP-Ribosa/metabolismo , ARN Helicasas/metabolismo , Proteínas con Motivos de Reconocimiento de ARN/metabolismo , Animales , Autoantígenos/inmunología , Autoantígenos/metabolismo , Enfermedades Autoinmunes del Sistema Nervioso/tratamiento farmacológico , Enfermedades Autoinmunes del Sistema Nervioso/genética , Catequina/análogos & derivados , Catequina/uso terapéutico , Repeticiones Palindrómicas Cortas Agrupadas y Regularmente Espaciadas , Citosol/inmunología , Citosol/metabolismo , ADN/inmunología , ADN/metabolismo , ADN Helicasas/antagonistas & inhibidores , ADN Helicasas/genética , Modelos Animales de Enfermedad , Exodesoxirribonucleasas/genética , Células HEK293 , Células HeLa , Humanos , Interferones/metabolismo , Ratones , Ratones Noqueados , Malformaciones del Sistema Nervioso/tratamiento farmacológico , Malformaciones del Sistema Nervioso/genética , Fármacos Neuroprotectores/uso terapéutico , Fosfoproteínas/genética , Proteínas de Unión a Poli-ADP-Ribosa/antagonistas & inhibidores , Proteínas de Unión a Poli-ADP-Ribosa/genética , Unión Proteica , ARN Helicasas/antagonistas & inhibidores , ARN Helicasas/genética , Proteínas con Motivos de Reconocimiento de ARN/antagonistas & inhibidores , Proteínas con Motivos de Reconocimiento de ARN/genéticaRESUMEN
The most massive and shortest-lived stars dominate the chemical evolution of the pre-galactic era. On the basis of numerical simulations, it has long been speculated that the mass of such first-generation stars was up to several hundred solar masses1-4. The very massive first-generation stars with a mass range from 140 to 260 solar masses are predicted to enrich the early interstellar medium through pair-instability supernovae (PISNe)5. Decades of observational efforts, however, have not been able to uniquely identify the imprints of such very massive stars on the most metal-poor stars in the Milky Way6,7. Here we report the chemical composition of a very metal-poor (VMP) star with extremely low sodium and cobalt abundances. The sodium with respect to iron in this star is more than two orders of magnitude lower than that of the Sun. This star exhibits very large abundance variance between the odd- and even-charge-number elements, such as sodium/magnesium and cobalt/nickel. Such peculiar odd-even effect, along with deficiencies of sodium and α elements, are consistent with the prediction of primordial pair-instability supernova (PISN) from stars more massive than 140 solar masses. This provides a clear chemical signature indicating the existence of very massive stars in the early universe.
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Superlattices-a periodic stacking of two-dimensional layers of two or more materials-provide a versatile scheme for engineering materials with tailored properties1,2. Here we report an intrinsic heterodimensional superlattice consisting of alternating layers of two-dimensional vanadium disulfide (VS2) and a one-dimensional vanadium sulfide (VS) chain array, deposited directly by chemical vapour deposition. This unique superlattice features an unconventional 1T stacking with a monoclinic unit cell of VS2/VS layers identified by scanning transmission electron microscopy. An unexpected Hall effect, persisting up to 380 kelvin, is observed when the magnetic field is in-plane, a condition under which the Hall effect usually vanishes. The observation of this effect is supported by theoretical calculations, and can be attributed to an unconventional anomalous Hall effect owing to an out-of-plane Berry curvature induced by an in-plane magnetic field, which is related to the one-dimensional VS chain. Our work expands the conventional understanding of superlattices and will stimulate the synthesis of more extraordinary superstructures.
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Histone posttranslational modifications (PTMs) regulate chromatin structure and dynamics during various DNA-associated processes. Here, we report that lysine glutarylation (Kglu) occurs at 27 lysine residues on human core histones. Using semi-synthetic glutarylated histones, we show that an evolutionarily conserved Kglu at histone H4K91 destabilizes nucleosome in vitro. In Saccharomyces cerevisiae, the replacement of H4K91 by glutamate that mimics Kglu influences chromatin structure and thereby results in a global upregulation of transcription and defects in cell-cycle progression, DNA damage repair, and telomere silencing. In mammalian cells, H4K91glu is mainly enriched at promoter regions of highly expressed genes. A downregulation of H4K91glu is tightly associated with chromatin condensation during mitosis and in response to DNA damage. The cellular dynamics of H4K91glu is controlled by Sirt7 as a deglutarylase and KAT2A as a glutaryltransferase. This study designates a new histone mark (Kglu) as a new regulatory mechanism for chromatin dynamics.
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Ensamble y Desensamble de Cromatina , Daño del ADN , Glutaratos/metabolismo , Histonas/metabolismo , Mitosis , Nucleosomas/metabolismo , Procesamiento Proteico-Postraduccional , Proteínas de Saccharomyces cerevisiae/metabolismo , Saccharomyces cerevisiae/metabolismo , Animales , Células HEK293 , Células HL-60 , Células HeLa , Células Hep G2 , Histona Acetiltransferasas/genética , Histona Acetiltransferasas/metabolismo , Humanos , Lisina , Ratones , Nucleosomas/genética , Células RAW 264.7 , Saccharomyces cerevisiae/genética , Saccharomyces cerevisiae/crecimiento & desarrollo , Proteínas de Saccharomyces cerevisiae/genética , Sirtuinas/genética , Sirtuinas/metabolismo , Factores de TiempoRESUMEN
Essential for reactive oxygen species (EROS) protein is a recently identified molecular chaperone of NOX2 (gp91phox), the catalytic subunit of phagocyte NADPH oxidase. Deficiency in EROS is a recently identified cause for chronic granulomatous disease, a genetic disorder with recurrent bacterial and fungal infections. Here, we report a cryo-EM structure of the EROS-NOX2-p22phox heterotrimeric complex at an overall resolution of 3.56Å. EROS and p22phox are situated on the opposite sides of NOX2, and there is no direct contact between them. EROS associates with NOX2 through two antiparallel transmembrane (TM) α-helices and multiple ß-strands that form hydrogen bonds with the cytoplasmic domain of NOX2. EROS binding induces a 79° upward bend of TM2 and a 48° backward rotation of the lower part of TM6 in NOX2, resulting in an increase in the distance between the two hemes and a shift of the binding site for flavin adenine dinucleotide (FAD). These conformational changes are expected to compromise superoxide production by NOX2, suggesting that the EROS-bound NOX2 is in a protected state against activation. Phorbol myristate acetate, an activator of NOX2 in vitro, is able to induce dissociation of NOX2 from EROS with concurrent increase in FAD binding and superoxide production in a transfected COS-7 model. In differentiated neutrophil-like HL-60, the majority of NOX2 on the cell surface is dissociated with EROS. Further studies are required to delineate how EROS dissociates from NOX2 during its transport to cell surface, which may be a potential mechanism for regulation of NOX2 activation.
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Microscopía por Crioelectrón , NADPH Oxidasa 2 , NADPH Oxidasas , Fagocitos , Humanos , NADPH Oxidasa 2/metabolismo , NADPH Oxidasa 2/genética , NADPH Oxidasa 2/química , Fagocitos/metabolismo , NADPH Oxidasas/metabolismo , NADPH Oxidasas/genética , NADPH Oxidasas/química , Unión Proteica , Sitios de Unión , Enfermedad Granulomatosa Crónica/metabolismo , Enfermedad Granulomatosa Crónica/genética , Modelos Moleculares , Especies Reactivas de Oxígeno/metabolismoRESUMEN
Chromatin replication is intricately intertwined with the recycling of parental histones to the newly duplicated DNA strands for faithful genetic and epigenetic inheritance. The transfer of parental histones occurs through two distinct pathways: leading strand deposition, mediated by the DNA polymerase ε subunits Dpb3/Dpb4, and lagging strand deposition, facilitated by the MCM helicase subunit Mcm2. However, the mechanism of the facilitation of Mcm2 transferring parental histones to the lagging strand while moving along the leading strand remains unclear. Here, we show that the deletion of Pol32, a nonessential subunit of major lagging-strand DNA polymerase δ, results in a predominant transfer of parental histone H3-H4 to the leading strand during replication. Biochemical analyses further demonstrate that Pol32 can bind histone H3-H4 both in vivo and in vitro. The interaction of Pol32 with parental histone H3-H4 is disrupted through the mutation of the histone H3-H4 binding domain within Mcm2. Our findings identify the DNA polymerase δ subunit Pol32 as a critical histone chaperone downstream of Mcm2, mediating the transfer of parental histones to the lagging strand during DNA replication.
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Replicación del ADN , ADN Polimerasa Dirigida por ADN , Proteínas de Saccharomyces cerevisiae , ADN Polimerasa III/metabolismo , ADN Polimerasa III/genética , Histonas/metabolismo , Componente 2 del Complejo de Mantenimiento de Minicromosoma/metabolismo , Componente 2 del Complejo de Mantenimiento de Minicromosoma/genética , Unión Proteica , Saccharomyces cerevisiae/genética , Saccharomyces cerevisiae/metabolismo , Proteínas de Saccharomyces cerevisiae/metabolismo , Proteínas de Saccharomyces cerevisiae/genética , ADN Polimerasa Dirigida por ADN/metabolismoRESUMEN
Extracellular matrix (ECM) rigidity serves as a crucial mechanical cue impacting diverse biological processes. However, understanding the molecular mechanisms of rigidity sensing has been limited by the spatial resolution and force sensitivity of current cellular force measurement techniques. Here we developed a method to functionalize DNA tension probes on soft hydrogel surfaces in a controllable and reliable manner, enabling molecular tension fluorescence microscopy for rigidity sensing studies. Our findings showed that fibroblasts respond to substrate rigidity by recruiting more force-bearing integrins and modulating integrin sampling frequency of the ECM, rather than simply overloading the existing integrin-ligand bonds, to promote focal adhesion maturation. We also demonstrated that ECM rigidity positively regulates the pN force of T cell receptor-ligand bond and T cell receptor mechanical sampling frequency, promoting T cell activation. Thus, hydrogel-based molecular tension fluorescence microscopy implemented on a standard confocal microscope provides a simple and effective means to explore detailed molecular force information for rigidity-dependent biological processes.
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Hidrogeles , Integrinas , Ligandos , Adhesiones Focales/química , Microscopía Fluorescente , Receptores de Antígenos de Linfocitos T , Adhesión CelularRESUMEN
Inflammasomes play pivotal roles in inflammation by processing and promoting the secretion of IL-1ß. Caspase-1 is involved in the maturation of IL-1ß and IL-18, while human caspase-4 specifically processes IL-18. Recent structural studies of caspase-4 bound to Pro-IL-18 reveal the molecular basis of Pro-IL-18 activation by caspase-4. However, the mechanism of caspase-1 processing of pro-IL-1ß and other IL-1ß-converting enzymes remains elusive. Here, we observed that swine Pro-IL-1ß (sPro-IL-1ß) exists as an oligomeric precursor unlike monomeric human Pro-IL-1ß (hPro-IL-1ß). Interestingly, Seneca Valley Virus (SVV) 3C protease cleaves sPro-IL-1ß to produce mature IL-1ß, while it cleaves hPro-IL-1ß but does not produce mature IL-1ß in a specific manner. When the inflammasome is blocked, SVV 3C continues to activate IL-1ß through direct cleavage in porcine alveolar macrophages (PAMs). Through molecular modeling and mutagenesis studies, we discovered that the pro-domain of sPro-IL-1ß serves as an 'exosite' with its hydrophobic residues docking into a positively charged 3C protease pocket, thereby directing the substrate to the active site. The cleavage of sPro-IL-1ß generates a monomeric and active form of IL-1ß, initiating the downstream signaling. Thus, these studies provide IL-1ß is an inflammatory sensor that directly detects viral protease through an independent pathway operating in parallel with host inflammasomes.
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Proteasas Virales 3C , Inflamasomas , Interleucina-1beta , Picornaviridae , Proteínas Virales , Animales , Interleucina-1beta/metabolismo , Proteasas Virales 3C/metabolismo , Porcinos , Humanos , Proteínas Virales/metabolismo , Inflamasomas/metabolismo , Inflamación/metabolismo , Infecciones por Picornaviridae/metabolismo , Infecciones por Picornaviridae/virología , Cisteína Endopeptidasas/metabolismo , Especificidad de la Especie , Macrófagos Alveolares/virología , Macrófagos Alveolares/metabolismoRESUMEN
With the ability to maximize the exposure of nearly all active sites to reactions, two-dimensional transition metal dichalcogenide (TMD) has become a fascinating new class of materials for electrocatalysis. Recently, electrochemical microcells have been developed, and their unique spatial-confined capability enables understanding of catalytic behaviors at a single material level, significantly promoting this field. This Review provides an overview of the recent progress in microcell-based TMD electrocatalyst studies. We first introduced the structural characteristics of TMD materials and discussed their site engineering strategies for electrocatalysis. Later, we comprehensively described two distinct types of microcells: the window-confined on-chip electrochemical microcell (OCEM) and the droplet-confined scanning electrochemical cell microscopy (SECCM). Their setups, working principles, and instrumentation were elucidated in detail, respectively. Furthermore, we summarized recent advances of OCEM and SECCM obtained in TMD catalysts, such as active site identification and imaging, site monitoring, modulation of charge injection and transport, and electrostatic field gating. Finally, we discussed the current challenges and provided personal perspectives on electrochemical microcell research.
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Two-dimensional (2D) materials1-5 offer a unique platform from which to explore the physics of topology and many-body phenomena. New properties can be generated by filling the van der Waals gap of 2D materials with intercalants6,7; however, post-growth intercalation has usually been limited to alkali metals8-10. Here we show that the self-intercalation of native atoms11,12 into bilayer transition metal dichalcogenides during growth generates a class of ultrathin, covalently bonded materials, which we name ic-2D. The stoichiometry of these materials is defined by periodic occupancy patterns of the octahedral vacancy sites in the van der Waals gap, and their properties can be tuned by varying the coverage and the spatial arrangement of the filled sites7,13. By performing growth under high metal chemical potential14,15 we can access a range of tantalum-intercalated TaS(Se)y, including 25% Ta-intercalated Ta9S16, 33.3% Ta-intercalated Ta7S12, 50% Ta-intercalated Ta10S16, 66.7% Ta-intercalated Ta8Se12 (which forms a Kagome lattice) and 100% Ta-intercalated Ta9Se12. Ferromagnetic order was detected in some of these intercalated phases. We also demonstrate that self-intercalated V11S16, In11Se16 and FexTey can be grown under metal-rich conditions. Our work establishes self-intercalation as an approach through which to grow a new class of 2D materials with stoichiometry- or composition-dependent properties.
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An amendment to this paper has been published and can be accessed via a link at the top of the paper.
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The human GABAB receptor-a member of the class C family of G-protein-coupled receptors (GPCRs)-mediates inhibitory neurotransmission and has been implicated in epilepsy, pain and addiction1. A unique GPCR that is known to require heterodimerization for function2-6, the GABAB receptor has two subunits, GABAB1 and GABAB2, that are structurally homologous but perform distinct and complementary functions. GABAB1 recognizes orthosteric ligands7,8, while GABAB2 couples with G proteins9-14. Each subunit is characterized by an extracellular Venus flytrap (VFT) module, a descending peptide linker, a seven-helix transmembrane domain and a cytoplasmic tail15. Although the VFT heterodimer structure has been resolved16, the structure of the full-length receptor and its transmembrane signalling mechanism remain unknown. Here we present a near full-length structure of the GABAB receptor, captured in an inactive state by cryo-electron microscopy. Our structure reveals several ligands that preassociate with the receptor, including two large endogenous phospholipids that are embedded within the transmembrane domains to maintain receptor integrity and modulate receptor function. We also identify a previously unknown heterodimer interface between transmembrane helices 3 and 5 of both subunits, which serves as a signature of the inactive conformation. A unique 'intersubunit latch' within this transmembrane interface maintains the inactive state, and its disruption leads to constitutive receptor activity.
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Microscopía por Crioelectrón , Receptores de GABA-B/química , Receptores de GABA-B/ultraestructura , Calcio/metabolismo , Etanolaminas/química , Etanolaminas/metabolismo , Humanos , Ligandos , Modelos Moleculares , Fosforilcolina/química , Fosforilcolina/metabolismo , Dominios Proteicos , Multimerización de Proteína , Subunidades de Proteína/química , Subunidades de Proteína/metabolismo , Receptores de GABA-B/metabolismo , Relación Estructura-ActividadRESUMEN
Gastroenteritis is among the leading causes of mortality globally in infants and young children, with rotavirus (RV) causing ~258 million episodes of diarrhea and ~128,000 deaths annually in infants and children. RV-induced mechanisms that result in diarrhea are not completely understood, but malabsorption is a contributing factor. RV alters cellular lipid metabolism by inducing lipid droplet (LD) formation as a platform for replication factories named viroplasms. A link between LD formation and gastroenteritis has not been identified. We found that diacylglycerol O-acyltransferase 1 (DGAT1), the terminal step in triacylglycerol synthesis required for LD biogenesis, is degraded in RV-infected cells by a proteasome-mediated mechanism. RV-infected DGAT1-silenced cells show earlier and increased numbers of LD-associated viroplasms per cell that translate into a fourfold-to-fivefold increase in viral yield (P < 0.05). Interestingly, DGAT1 deficiency in children is associated with diarrhea due to altered trafficking of key ion transporters to the apical brush border of enterocytes. Confocal microscopy and immunoblot analyses of RV-infected cells and DGAT1-/- human intestinal enteroids (HIEs) show a decrease in expression of nutrient transporters, ion transporters, tight junctional proteins, and cytoskeletal proteins. Increased phospho-eIF2α (eukaryotic initiation factor 2 alpha) in DGAT1-/- HIEs, and RV-infected cells, indicates a mechanism for malabsorptive diarrhea, namely inhibition of translation of cellular proteins critical for nutrient digestion and intestinal absorption. Our study elucidates a pathophysiological mechanism of RV-induced DGAT1 deficiency by protein degradation that mediates malabsorptive diarrhea, as well as a role for lipid metabolism, in the pathogenesis of gastroenteritis.
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Gastroenteritis , Infecciones por Rotavirus , Rotavirus , Niño , Lactante , Humanos , Preescolar , Rotavirus/metabolismo , Diacilglicerol O-Acetiltransferasa/genética , Diacilglicerol O-Acetiltransferasa/metabolismo , Replicación Viral , Diarrea , Infecciones por Rotavirus/genéticaRESUMEN
Although tumor-intrinsic fatty acid ß-oxidation (FAO) is implicated in multiple aspects of tumorigenesis and progression, the impact of this metabolic pathway on cancer cell susceptibility to immunotherapy remains unknown. Here, we report that cytotoxicity of killer T cells induces activation of FAO and upregulation of carnitine palmitoyltransferase 1A (CPT1A), the rate-limiting enzyme of FAO in cancer cells. The repression of CPT1A activity or expression renders cancer cells more susceptible to destruction by cytotoxic T lymphocytes. Our mechanistic studies reveal that FAO deficiency abrogates the prosurvival signaling in cancer cells under immune cytolytic stress. Furthermore, we identify T cell-derived IFN-γ as a major factor responsible for induction of CPT1A and FAO in an AMPK-dependent manner, indicating a dynamic interplay between immune effector cells and tumor targets. While cancer growth in the absence of CPT1A remains largely unaffected, established tumors upon FAO inhibition become significantly more responsive to cellular immunotherapies including chimeric antigen receptor-engineered human T cells. Together, these findings uncover a mode of cancer resistance and immune editing that can facilitate immune escape and limit the benefits of immunotherapies.