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The tumor suppressor Liver Kinase B1 (LKB1) is a multifunctional serine/threonine protein kinase that regulates cell metabolism, polarity, and growth and is associated with Peutz-Jeghers Syndrome and cancer predisposition. The LKB1 gene comprises 10 exons and 9 introns. Three spliced LKB1 variants have been documented, and they reside mainly in the cytoplasm, although two possess a nuclear-localization sequence (NLS) and are able to shuttle into the nucleus. Here, we report the identification of a fourth and novel LKB1 isoform that is, interestingly, targeted to the mitochondria. We show that this mitochondria-localized LKB1 (mLKB1) is generated from alternative splicing in the 5' region of the transcript and translated from an alternative initiation codon encoded by a previously unknown exon 1b (131 bp) hidden within the long intron 1 of LKB1 gene. We found by replacing the N-terminal NLS of the canonical LKB1 isoform, the N-terminus of the alternatively spliced mLKB1 variant encodes a mitochondrial transit peptide that allows it to localize to the mitochondria. We further demonstrate that mLKB1 colocalizes histologically with mitochondria-resident ATP Synthase and NAD-dependent deacetylase sirtuin-3, mitochondrial (SIRT3) and that its expression is rapidly and transiently upregulated by oxidative stress. We conclude that this novel LKB1 isoform, mLKB1, plays a critical role in regulating mitochondrial metabolic activity and oxidative stress response.
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Quinasas de la Proteína-Quinasa Activada por el AMP , Mitocondrias , Mutación , Estrés Oxidativo , Proteínas Serina-Treonina Quinasas , Quinasas de la Proteína-Quinasa Activada por el AMP/genética , Quinasas de la Proteína-Quinasa Activada por el AMP/metabolismo , Mitocondrias/genética , Mitocondrias/metabolismo , Estrés Oxidativo/genética , Isoformas de Proteínas/genética , Isoformas de Proteínas/metabolismo , Proteínas Serina-Treonina Quinasas/genética , Proteínas Serina-Treonina Quinasas/metabolismo , Sirtuina 3/metabolismo , Señales de Clasificación de Proteína , Transporte de Proteínas , ATPasas de Translocación de Protón Mitocondriales/metabolismo , Empalme Alternativo , Codón IniciadorRESUMEN
BACKGROUND: Fear of a global public health issue and fresh infection wave in the persistent COVID-19 pandemic has been enflamed by the appearance of the novel variant Omicron BF.7 lineage. Recently, it has been seeing the novel Omicron subtype BF.7 lineage has sprawled exponentially in Hohhot. More than anything, risk stratification is significant to ascertain patients infected with COVID-19 who the most need in-hospital or in-home management. The study intends to understand the clinical severity and epidemiological characteristics of COVID-19 Omicron subvariant BF.7. lineage via gathering and analyzing the cases with Omicron subvariant in Hohhot, Inner Mongolia. METHODS: Based upon this, we linked variant Omicron BF.7 individual-level information including sex, age, symptom, underlying conditions and vaccination record. Further, we divided the cases into various groups and assessed the severity of patients according to the symptoms of patients with COVID-19. Clinical indicators and data might help to predict disadvantage outcomes and progression among Omicron BF.7 patients. RESULTS: In this study, in patients with severe symptoms, some indicators from real world data such as white blood cells, AST, ALT and CRE in patients with Omicron BF.7 in severe symptoms were significantly higher than mild and asymptomatic patients, while some indicators were significantly lower. CONCLUSIONS: Above results suggested that the indicators were associated with ponderance of clinical symptoms. Our survey emphasized the value of timely investigations of clinical data obtained by systemic study to acquire detailed information.
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COVID-19 , Humanos , Estudios Retrospectivos , COVID-19/epidemiología , Pandemias , China/epidemiología , Salud PúblicaRESUMEN
Fas Apoptotic Inhibitory Molecule protein (FAIM) is a death receptor antagonist and an apoptosis regulator. It encodes two isoforms, namely FAIM-S (short) and FAIM-L (long), both with significant neuronal functions. FAIM-S, which is ubiquitously expressed, is involved in neurite outgrowth. In contrast, FAIM-L is expressed only in neurons and it protects them from cell death. Interestingly, FAIM-L is downregulated in patients and mouse models of Alzheimer's disease before the onset of neurodegeneration, and Faim transcript levels are decreased in mouse models of retinal degeneration. However, few studies have addressed the role of FAIM in the central nervous system, yet alone the retina. The retina is a highly specialized tissue, and its degeneration has proved to precede pathological mechanisms of neurodegenerative diseases. Here we describe that Faim depletion in mice damages the retina persistently and leads to late-onset photoreceptor death in older mice. Immunohistochemical analyses showed that Faim knockout (Faim-/- ) mice present ubiquitinated aggregates throughout the retina from early ages. Moreover, retinal cells released stress signals that can signal to Müller cells, as shown by immunofluorescence and qRT-PCR. Müller cells monitor retinal homeostasis and trigger a gliotic response in Faim-/- mice that becomes pathogenic when sustained. In this regard, we observed pronounced vascular leakage at later ages, which may be caused by persistent inflammation. These results suggest that FAIM is an important player in the maintenance of retinal homeostasis, and they support the premise that FAIM is a plausible early marker for late photoreceptor and neuronal degeneration.
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Proteínas Reguladoras de la Apoptosis , Gliosis , Neuronas , Animales , Proteínas Reguladoras de la Apoptosis/genética , Proteínas Reguladoras de la Apoptosis/metabolismo , Proteínas Reguladoras de la Apoptosis/fisiología , Muerte Celular , Gliosis/patología , Ratones , Neuronas/metabolismo , RetinaRESUMEN
Toll-like receptor 3 (TLR3) mediates antiviral response by recognizing double-stranded RNA. Its cytoplasmic domain is tyrosine phosphorylated upon ligand binding and initiates downstream signaling via the adapter TIR-containing adaptor inducing interferon-ß (TRIF). However, the kinase responsible for TLR3 phosphorylation remains unknown. We show here that Bruton's tyrosine kinase (BTK)-deficient macrophages failed to secrete inflammatory cytokines and IFN-ß upon TLR3 stimulation and were impaired in clearing intracellular dengue virus infection. Mutant mice were also less susceptible to d-galactosamine/p(I:C)-induced sepsis. In the absence of BTK, TLR3-induced phosphoinositide 3-kinase (PI3K), AKT and MAPK signaling and activation of NFκB, IRF3, and AP-1 transcription factors were all defective. We demonstrate that BTK directly phosphorylates TLR3 and in particular the critical Tyr759 residue. BTK point mutations that abrogate or led to constitutive kinase activity have opposite effects on TLR3 phosphorylation. Loss of BTK also compromises the formation of the downstream TRIF/receptor-interacting protein 1 (RIP1)/TBK1 complex. Thus, BTK plays a critical role in initiating TLR3 signaling.
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Antivirales/inmunología , Virus del Dengue/inmunología , Proteínas Tirosina Quinasas/metabolismo , Receptor Toll-Like 3/metabolismo , Proteínas Adaptadoras del Transporte Vesicular/metabolismo , Agammaglobulinemia Tirosina Quinasa , Animales , Citocinas/biosíntesis , Virus del Dengue/fisiología , Activación Enzimática , Proteínas Activadoras de GTPasa/metabolismo , Células HEK293 , Humanos , Interferón beta/biosíntesis , Sistema de Señalización de MAP Quinasas , Activación de Macrófagos , Macrófagos/enzimología , Macrófagos/virología , Ratones , Ratones Endogámicos C57BL , Fosfatidilinositol 3-Quinasas/metabolismo , Fosforilación , Proteínas Serina-Treonina Quinasas/metabolismo , Proteínas Tirosina Quinasas/deficiencia , Proteínas Proto-Oncogénicas c-akt/metabolismo , Factores de Transcripción/metabolismo , Replicación ViralRESUMEN
MicroRNAs (miRNAs) are short noncoding RNAs that regulate gene expression and are important for pre-B and follicular B lymphopoiesis as demonstrated, respectively, by mb-1-Cre- and cd19-Cre-mediated deletion of Dicer, the RNase III enzyme critical for generating mature miRNAs. To explore the role of miRNAs in B-cell terminal differentiation, we use Aicda-Cre to specifically delete Dicer in activated B cells where activation-induced cytidine deaminase is highly expressed. We demonstrate that mutant mice fail to produce high-affinity class-switched antibodies and generate memory B and long-lived plasma cells on immunization with a T cell-dependent antigen. More importantly, germinal center (GC) B-cell formation is drastically compromised in the absence of Dicer, as a result of defects in cell proliferation and survival. Dicer-deficient GC B cells express higher levels of cell cycle inhibitor genes and proapoptotic protein Bim. Ablation of Bim could partially rescue the defect in GC B-cell formation in Dicer-deficient mice. Taken together, our data suggest that Dicer and probably miRNAs are critical for GC B-cell formation during B-cell terminal differentiation.
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Linfocitos B/citología , Diferenciación Celular , Citidina Desaminasa/fisiología , ARN Helicasas DEAD-box/fisiología , Centro Germinal/citología , Células Plasmáticas/inmunología , Ribonucleasa III/fisiología , Animales , Apoptosis , Linfocitos B/metabolismo , Proliferación Celular , Ensayo de Inmunoadsorción Enzimática , Femenino , Citometría de Flujo , Centro Germinal/metabolismo , Inmunización , Memoria Inmunológica , Integrasas/metabolismo , Masculino , Ratones , Ratones Noqueados , Células Plasmáticas/metabolismo , Edición de ARN , Linfocitos T/inmunología , Linfocitos T/metabolismoRESUMEN
Apart from their killer identity, natural killer (NK) cells have integral roles in shaping the tumor microenvironment. Through immune gene deconvolution, the present study revealed an interplay between NK cells and myeloid-derived suppressor cells (MDSCs) in nonresponders of immune checkpoint therapy. Given that the mechanisms governing the outcome of NK cell-to-myeloid cell interactions remain largely unknown, we sought to investigate the cross-talk between NK cells and suppressive myeloid cells. Upon contact with tumor-experienced NK cells, monocytes and neutrophils displayed increased expression of MDSC-related suppressive factors along with increased capacities to suppress T cells. These changes were accompanied by impaired antigen presentation by monocytes and increased ER stress response by neutrophils. In a cohort of patients with sarcoma and breast cancer, the production of interleukin-6 (IL-6) by tumor-infiltrating NK cells correlated with S100A8/9 and arginase-1 expression by MDSCs. At the same time, NK cell-derived IL-6 was associated with tumors with higher major histocompatibility complex class I expression, which we further validated with b2m-knockout (KO) tumor mice models. Similarly in syngeneic wild-type and IL-6 KO mouse models, we then demonstrated that the accumulation of MDSCs was influenced by the presence of such regulatory NK cells. Inhibition of the IL-6/signal transducer and activator of transcription 3 (STAT3) axis alleviated suppression of T cell responses, resulting in reduced tumor growth and metastatic dissemination. Together, these results characterize a critical NK cell-mediated mechanism that drives the development of MDSCs during tumor immune escape.
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Tolerancia Inmunológica , Interleucina-6 , Células Asesinas Naturales , Células Supresoras de Origen Mieloide , Factor de Transcripción STAT3 , Factor de Transcripción STAT3/metabolismo , Células Asesinas Naturales/inmunología , Células Asesinas Naturales/metabolismo , Interleucina-6/metabolismo , Células Supresoras de Origen Mieloide/metabolismo , Células Supresoras de Origen Mieloide/inmunología , Animales , Humanos , Transducción de Señal , Microambiente Tumoral/inmunología , Ratones Noqueados , Línea Celular Tumoral , Femenino , Ratones , Ratones Endogámicos C57BL , Neoplasias/inmunología , Neoplasias/patologíaRESUMEN
T-cell-engaging bispecific antibodies (T-bsAbs) are promising immunotherapies for cancer treatment due to their capability of redirecting T-cells toward destroying tumor cells. Numerous T-bsAb formats have been developed, each with advantages and disadvantages in terms of developability, immunogenicity, effector functions, and pharmacokinetics. Here, we systematically compared T-bsAbs produced using eight different formats, evaluating the effect of molecular design of T-bsAbs on their manufacturability and functionality. These eight T-bsAb formats were constructed using antigen-binding fragments (Fabs) and single-chain variable fragments (scFvs) of antibodies linked to the crystallizable fragment (Fc) domain of immunoglobulin G. To ensure a fair comparison of growth and production data, we used recombinase-mediated cassette exchange technology to generate the T-bsAb-producing CHO cell lines. The produced T-bsAbs were assessed for their purification profile and recovery, binding capability, and biological activities. Our findings indicated that the manufacturability of bsAbs was adversely affected with increased number of scFv building blocks, while the functionality was affected by the combination of multiple factors, including the binding affinity and avidity of targeting moieties and the flexibility and geometry of formats. These results provide valuable insights into the impact of the format design on the optimal production and function of T-bsAbs.
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Anticuerpos Biespecíficos , Anticuerpos de Cadena Única , Linfocitos T , Fragmentos Fab de Inmunoglobulinas , Inmunoglobulina GRESUMEN
Naïve B cells become activated and differentiate into antibody-secreting plasma cells (PCs) when encountering antigens. Here, we reveal that the WW domain-containing adapter protein with coiled-coil (Wac), which is important for histone H2B ubiquitination (ubH2B), is essential for PC differentiation. We demonstrate that B cell-specific Wac knockout mice have severely compromised T cell-dependent and -independent antibody responses. PC differentiation is drastically compromised despite undisturbed germinal center B cell response in the mutant mice. We also observe a significant reduction in global ubH2B in Wac-deficient B cells, which is correlated with downregulated expression of some genes critical for cell metabolism. Thus, our findings demonstrate an essential role of Wac-mediated ubH2B in PC differentiation and shed light on the epigenetic mechanisms underlying this process.
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Proteínas Adaptadoras Transductoras de Señales , Histonas , Animales , Ratones , Proteínas Adaptadoras Transductoras de Señales/metabolismo , Diferenciación Celular , Epigénesis Genética , Histonas/genética , Histonas/metabolismo , UbiquitinaciónRESUMEN
Multiple Omicron sub-lineages have emerged, with Omicron XBB and XBB.1.5 subvariants becoming the dominant variants globally at the time of this study. The key feature of new variants is their ability to escape humoral immunity despite the fact that there are limited genetic changes from their preceding variants. This raises the question of whether Omicron should be regarded as a separate serotype from viruses serologically clustered with the ancestral severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2) virus. Here, we present cross-neutralization data based on a pseudovirus neutralization test using convalescent sera from naïve individuals who had recovered from primary infection by SARS-CoV-1 and SARS-CoV-2 strains/variants including the ancestral virus and variants Beta, Delta, Omicron BA.1, Omicron BA.2 and Omicron BA.5. The results revealed no significant cross-neutralization in any of the three-way testing for SARS-CoV-1, ancestral SARS-CoV-2 and SARS-CoV-2 Omicron subvariants. The data argue for the assignment of three distinct serotypes for the currently known human-infecting SARS-related coronaviruses.
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The advent of the Omicron variant globally has hastened the requirement for a booster vaccination dose to confer continuous protection against symptomatic SARS-CoV2 infection. However, different vaccines are available in different countries, and individuals who had adverse reactions to certain vaccine types require heterologous vaccine boosters. To understand the efficacy of different vaccination regimens in inducing humoral responses to SARS-CoV2, we examined plasma antibodies and frequencies of Omicron RBD-specific B cells in individuals who had different priming-booster vaccination regimens. We found that individuals with three homologous doses of mRNA vaccines had higher levels of IgG of all subclasses against RBD of Omicron than individuals with three homologous doses of inactivated virus vaccine. A booster with mRNA vaccine resulted in significant increases in median levels of RBD-reactive IgG1 (17-19 fold) and IgG3 (2.3-3.3 fold) as compared to individuals receiving inactivated virus booster shots regardless of priming vaccine types. More importantly, individuals who received a booster dose of mRNA vaccine, irrespective of the priming vaccine, had antibodies with higher neutralizing capability against the Omicron variant than those who received a booster dose of inactivated virus vaccine. Corroborating the antibody results, boosting with the mRNA vaccine increased the frequencies of Omicron RBD-binding B cells by (1.5-3.3 fold) regardless of priming vaccine types. Together, our data demonstrate that an mRNA vaccine (BNT162b2 or mRNA-1273) booster enhances humoral responses against the Omicron variant in individuals vaccinated with either two prior doses of mRNA or inactivated virus vaccine (CoronaVac or BBIBP-CorV), potentially providing more effective protection against SARS-CoV-2 infection, particularly by the Omicron variant.
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Background: Multiple myeloma (MM) is the second most common hematological malignancy. It has emerged as one of the next possible hematological diseases amenable to immunotherapy. B-cell maturation antigen (BCMA), a member of the tumor necrosis factor receptor superfamily, is highly expressed in MM cells and is one target with the most potential for developing MM-targeting immunotherapy. Other than the FDA-approved BCMA-targeting CAR T-cell therapy, such as Abecma and CARVYKTI, T cell-engaging multi-specific antibody is another promising therapeutic modality for BCMA-targeting MM treatment. We develop a T-cell redirecting BCMA-targeting bispecific antibody (bsAb) and evaluate its anti-MM activity. Methods: We first generated several clones of mouse anti-human BCMA monoclonal antibodies using DNA immunization. One of the anti-BCMA antibodies was then used to design and produce a T cell-redirecting BCMA × CD3 bsAb in CHO cells. Finally, we examined the effect of the bsAb on MM cell growth both in vitro and in vivo. Results: The BCMA × CD3 bsAb was designed in a FabscFv format and produced in CHO cells with good yield and purity. Moreover, the bsAb can trigger robust T cell proliferation and activation and induce efficient T cell-mediated MM cell killing in vitro. Using a MM xenograft mouse model, we demonstrate that the bsAb can effectively suppress MM cell growth in vivo. Conclusions: Our results suggest that the BCMA × CD3 bsAb in the FabscFv format can efficiently inhibit MM cell growth and have promising potential to be developed into a therapeutic antibody drug for the treatment of MM.
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INTRODUCTION: We compared the early total spike antibody (S-Ab) and neutralizing antibody (N-Ab) responses to two vaccines. METHODS: We studied 96 Pfizer and 34 Sinovac vaccinees over a 14-month period from January 2021 to February 2022. All vaccinees received three doses of one type of vaccine. Antibody levels (Roche Elecsys total S-Ab and the Snibe N-Ab) were tested 10 days after the first dose, 20 days after the second dose, and 20 days after the booster dose. RESULTS: At all time points, the mRNA vaccine generated higher S-Ab and N-Ab responses than the inactivated virus vaccine (S-Ab: first dose 2.48 vs. 0.4 BAU/mL, second dose 2174 vs. 98 BAU/mL, third dose 15,004 vs. 525 BAU/mL; N-Ab: first dose 0.05 vs. 0.02 µg/mL, second dose 3.48 vs. 0.38 µg/mL, third dose 19.8 vs. 0.89 µg/mL). mRNA vaccine recipients had a 6.2/22.2/28.6-fold higher S-Ab and 2.5/9.2/22.2-fold higher N-Ab response than inactivated virus vaccine recipients after the first/second/third inoculations, respectively. Mann-Whitney U analysis confirmed the significant difference in S-Ab and N-Ab titers between vaccination groups at each time point. CONCLUSIONS: The mRNA vaccines generated a more robust S-Ab and N-Ab response than the inactivated virus vaccine at all time points after the first, second, and third vaccinations.
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INTRODUCTION: We documented the total spike antibody (S-Ab), IgG S-Ab and neutralizing antibody (N-Ab) responses of BNT162b2/CoronaVac vaccinees up to 90 days post-booster dose. METHODS: We included 32 homologous regimen CoronaVac vaccinees and 136 BNT162b2 mRNA vaccinees. We tested their total S-Ab (Roche), IgG (Abbott) and N-Ab (Snibe) levels at set time points from January 2021 to April 2022. All subjects were deemed to be COVID-19-naïve either via clinical history (CoronaVac vaccinees) or nucleocapsid antibody testing (BNT162b2 vaccinees). RESULTS: All antibodies peaked 20-30 days post-inoculation. In BNT162b2 vaccinees, all post-booster antibodies were significantly higher than second-dose peaks. In CoronaVac vaccinees, IgG showed no significant differences between peak third-/second-dose titers (difference of 56.0 BAU/mL, 95% CI of -17.1 to 129, p = 0.0894). The post-vaccination titers of all antibodies in BNT162b2 vaccinees were significantly higher than those in CoronaVac vaccinees at all time points. Post-booster, all antibodies declined in 90 days; the final total/IgG/N-Ab titers were 7536 BAU/mL, 1276 BAU/mL and 12.5 µg/mL in BNT162b2 vaccinees and 646 BAU/mL, 62.4 BAU/mL and 0.44 µg/mL in CoronaVac vaccinees. CONCLUSION: The mRNA vaccine generated more robust total S-Ab, IgG and N-Ab responses after the second and third vaccinations.
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Fas apoptosis inhibitory molecule (FAIM) has been demonstrated to confer resistance to Fas-induced apoptosis of lymphocytes and hepatocytes in vitro and in vivo. Here, we show that FAIM is up-regulated in thymocytes upon T cell receptor (TCR) engagement and that faim(-/-) thymocytes are highly susceptible to TCR-mediated apoptosis with increased activation of caspase-8 and -9. Furthermore, injection of anti-CD3 antibodies leads to augmented depletion of CD4(+)CD8(+) T cells in the thymus of faim(-/-) mice compared with wild-type control, suggesting that FAIM plays a role in thymocyte apoptosis. Cross-linking of the TCR on faim(-/-) thymocytes leads to an elevated protein level of the orphan nuclear receptor Nur77, which plays a role in thymocyte apoptosis. Interestingly, in the absence of FAIM, there are reduced ubiquitination and degradation of the Nur77 protein. Faim(-/-) thymocytes also exhibit a defective TCR-induced activation of Akt whose activity we now show is required for Nur77 ubiquitination. Further analyses utilizing FAIM-deficient primary thymocytes and FAIM-overexpressing DO-11.10 T cells indicate that FAIM acts upstream of Akt during TCR signaling and influences the localization of Akt to lipid rafts, hence affecting its activation. Taken together, our study defined a TCR-induced FAIM/Akt/Nur77 signaling axis that is critical for modulating the apoptosis of developing thymocytes.
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Proteínas Reguladoras de la Apoptosis/metabolismo , Apoptosis/fisiología , Miembro 1 del Grupo A de la Subfamilia 4 de Receptores Nucleares/metabolismo , Proteínas Proto-Oncogénicas c-akt/metabolismo , Receptores de Antígenos de Linfocitos T/metabolismo , Linfocitos T/citología , Linfocitos T/metabolismo , Animales , Apoptosis/inmunología , Proteínas Reguladoras de la Apoptosis/deficiencia , Proteínas Reguladoras de la Apoptosis/genética , Caspasa 9/metabolismo , Activación Enzimática , Técnicas In Vitro , Microdominios de Membrana/metabolismo , Ratones , Proteínas Recombinantes/genética , Proteínas Recombinantes/metabolismo , Transducción de Señal , Subgrupos de Linfocitos T/citología , Subgrupos de Linfocitos T/inmunología , Subgrupos de Linfocitos T/metabolismo , Linfocitos T/inmunología , Transfección , Proteína Destructora del Antagonista Homólogo bcl-2/metabolismo , Proteína X Asociada a bcl-2/metabolismoRESUMEN
Inflammatory bowel disease (IBD) is driven by multiple genetic and environmental risk factors. Patients with mutations in Bruton's tyrosine kinase (BTK) is known to manifest high prevalence of intestinal disorders including IBD. Although BTK mediates the signaling of various immune receptors, little is known how BTK maintains the homeostasis of the gut immune system. Here, we show that BTK-deficiency promotes IBD progression in a mouse model of colitis. Interestingly, the increased colitis susceptibility of BTK-deficient mice is not caused by gut microbiota changes but rather arises from enhanced pro-inflammatory Th1 response. More importantly, we find the heightened Th1 response in BTK-deficient mice to result from both T cell-extrinsic and -intrinsic mechanisms. BTK-deficient dendritic cells secret elevated levels of the Th1-polarizing cytokine IL-12 and BTK-deficient T cells are inherently more prone to Th1 differentiation. Thus, BTK plays critical roles in maintaining gut immune homeostasis and preventing inflammation via regulating T-cell polarization.
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Agammaglobulinemia Tirosina Quinasa/genética , Homeostasis/genética , Células TH1/metabolismo , Animales , Humanos , RatonesRESUMEN
Cell metabolism plays a pivotal role in regulating the effector functions of immune cells. Stimulatory cytokines, such as interleukin (IL)-2 or IL-12 and IL-15, activate glycolysis and oxidative phosphorylation in natural killer (NK) cells to support their enhanced effector functions. IL-10, a pleiotropic cytokine, is known to suppress macrophage activation but stimulate NK cells. However, it remains unclear if IL-10 has an effect on the metabolism of human NK cells and if so, what metabolic mechanisms are affected, and how these metabolic changes are regulated and contribute to the effector functions of NK cells. In this study, we demonstrate that IL-10 upregulates both glycolysis and oxidative phosphorylation in human NK cells, and these metabolic changes are crucial for the enhanced effector functions of NK cells. Mechanistically, we unravel that IL-10 activates the mammalian target of rapamycin complex 1 (mTORC1) to regulate metabolic reprogramming in human NK cells.
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Reprogramación Celular , Metabolismo Energético , Interleucina-10/metabolismo , Células Asesinas Naturales/inmunología , Células Asesinas Naturales/metabolismo , Diana Mecanicista del Complejo 1 de la Rapamicina/metabolismo , Transducción de Señal , Línea Celular , Células Cultivadas , Reprogramación Celular/genética , Reprogramación Celular/inmunología , Citocinas/metabolismo , Citotoxicidad Inmunológica , Glucólisis , Humanos , Activación de Linfocitos/genética , Activación de Linfocitos/inmunología , Fosforilación OxidativaRESUMEN
: Apoptosis signal-regulating kinase 1 (ASK1) is a mitogen-activated protein kinase kinase kinase (MAPKKK) that activates downstream JNK and p38 mitogen-activated protein kinase (MAPK) to relay death signals into cells in response to various environmental stress. However, whether ASK1 plays a role in T cell receptor (TCR)-mediated apoptosis of thymocytes is unclear. Here, we show that ASK1 is activated upon TCR stimulation and plays an important role in TCR-mediated apoptosis of thymocytes by triggering downstream JNK and p38 signaling cascades. Mechanistically, ASK1-JNK/p38 signaling leads to the upregulation of neuron-derived clone 77 (Nur77), a critical pro-apoptotic protein involved in TCR-mediated apoptosis of thymocytes. Furthermore, we demonstrate that the activation of ASK1 is negatively modulated by Akt upon TCR stimulation. Thus, our results identify a previously unappreciated signaling mechanism involving ASK1 in TCR-mediated apoptosis of thymocytes.
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MAP Quinasa Quinasa Quinasa 5/metabolismo , Miembro 1 del Grupo A de la Subfamilia 4 de Receptores Nucleares/metabolismo , Receptores de Antígenos de Linfocitos T/metabolismo , Timocitos/metabolismo , Animales , Apoptosis/fisiología , Femenino , Sistema de Señalización de MAP Quinasas , Masculino , Ratones , Ratones Endogámicos C57BL , Timocitos/citología , Proteínas Quinasas p38 Activadas por Mitógenos/metabolismoRESUMEN
Fas Apoptosis Inhibitory Molecule (FAIM) is an anti-apoptotic protein that is up-regulated in B cell receptor (BCR)-activated B cells and confers upon them resistance to Fas-mediated cell death. Faim has two alternatively spliced isoforms, with the short isoform ubiquitously expressed in various tissues and the long isoform mainly found in the nervous tissues. FAIM is evolutionarily conserved but does not share any significant primary sequence homology with any known protein. The function of FAIM has been extensively studied in the past 20 years, with its primary role being ascribed to be anti-apoptotic. In addition, several other functions of FAIM were also discovered in different physiological and pathological conditions, such as cell growth, metabolism, Alzheimer's disease and tumorigenesis. However, the detailed molecular mechanisms underlying FAIM's role in these conditions remain unknown. In this review, we summarize comprehensively the functions of FAIM in these different contexts and discuss its potential as a diagnostic, prognostic or therapeutic target.
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Proteínas Reguladoras de la Apoptosis/antagonistas & inhibidores , Enfermedad de Alzheimer/metabolismo , Enfermedad de Alzheimer/patología , Apoptosis , Proteínas Reguladoras de la Apoptosis/metabolismo , Linfocitos B/citología , Linfocitos B/metabolismo , Metabolismo Energético , Humanos , Discapacidad Intelectual/metabolismo , Discapacidad Intelectual/patología , Mieloma Múltiple/metabolismo , Mieloma Múltiple/patología , Proteínas Proto-Oncogénicas c-akt/metabolismo , Receptores de Antígenos de Linfocitos T/metabolismoRESUMEN
Invariant natural killer T (iNKT) cells develop from CD4+CD8+ double-positive (DP) thymocytes and express an invariant Vα14-Jα18 T-cell receptor (TCR) α-chain. Generation of these cells requires the prolonged survival of DP thymocytes to allow for Vα14-Jα18 gene rearrangements and strong TCR signaling to induce the expression of the iNKT lineage-specific transcription factor PLZF. Here, we report that the transcription factor Yin Yang 1 (YY1) is essential for iNKT cell formation. Thymocytes lacking YY1 displayed a block in iNKT cell development at the earliest progenitor stage. YY1-deficient thymocytes underwent normal Vα14-Jα18 gene rearrangements, but exhibited impaired cell survival. Deletion of the apoptotic protein BIM failed to rescue the defect in iNKT cell generation. Chromatin immunoprecipitation and deep-sequencing experiments demonstrated that YY1 directly binds and activates the promoter of the Plzf gene. Thus, YY1 plays essential roles in iNKT cell development by coordinately regulating cell survival and PLZF expression.
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Células T Asesinas Naturales/inmunología , Proteína de la Leucemia Promielocítica con Dedos de Zinc/metabolismo , Receptores de Antígenos de Linfocitos T/metabolismo , Timocitos/inmunología , Factor de Transcripción YY1/metabolismo , Animales , Diferenciación Celular , Linaje de la Célula , Supervivencia Celular , Células Cultivadas , Humanos , Ratones , Ratones Endogámicos C57BL , Ratones Noqueados , Proteína de la Leucemia Promielocítica con Dedos de Zinc/genética , Receptores de Antígenos de Linfocitos T/genética , Transducción de Señal , Factor de Transcripción YY1/genéticaRESUMEN
B lymphocytes undergo metabolic reprogramming upon activation to meet the bioenergetic demands for proliferation and differentiation. Yet, little is known if and how the fate of naive B cells is metabolically regulated. Here, we specifically delete von Hippel-Lindau protein (VHL) in B cells using CD19-Cre and demonstrate that metabolic balance is essential for naive B cell survival. Loss of VHL disturbs glycolytic and oxidative metabolic balance and causes severe reduction in mature B cells. Mechanistically, the metabolic imbalance in VHL-deficient B cells, arising from over-stabilization of hypoxia-inducible factor-1α (HIF-1α), triggers reductive glutamine metabolism leading to increased Fas palmitoylation and caspase-8-mediated apoptosis. Blockade of reductive glutamine metabolic flux by lactate supplementation and ATP citrate lyase inhibition restores the metabolic balance and rectifies the impaired survival of VHL-deficient B cells. Hence, we unravel that the VHL/HIF-1α pathway is required to maintain the metabolic balance of naive B cells and ensure their survival.