Your browser doesn't support javascript.
loading
Mostrar: 20 | 50 | 100
Resultados 1 - 20 de 55
Filtrar
Más filtros

Bases de datos
Tipo del documento
Intervalo de año de publicación
1.
EMBO J ; 41(24): e112006, 2022 12 15.
Artículo en Inglés | MEDLINE | ID: mdl-36398858

RESUMEN

Mitochondria are increasingly recognized as cellular hubs to orchestrate signaling pathways that regulate metabolism, redox homeostasis, and cell fate decisions. Recent research revealed a role of mitochondria also in innate immune signaling; however, the mechanisms of how mitochondria affect signal transduction are poorly understood. Here, we show that the NF-κB pathway activated by TNF employs mitochondria as a platform for signal amplification and shuttling of activated NF-κB to the nucleus. TNF treatment induces the recruitment of HOIP, the catalytic component of the linear ubiquitin chain assembly complex (LUBAC), and its substrate NEMO to the outer mitochondrial membrane, where M1- and K63-linked ubiquitin chains are generated. NF-κB is locally activated and transported to the nucleus by mitochondria, leading to an increase in mitochondria-nucleus contact sites in a HOIP-dependent manner. Notably, TNF-induced stabilization of the mitochondrial kinase PINK1 furthermore contributes to signal amplification by antagonizing the M1-ubiquitin-specific deubiquitinase OTULIN. Overall, our study reveals a role for mitochondria in amplifying TNF-mediated NF-κB activation, both serving as a signaling platform, as well as a transport mode for activated NF-κB to the nuclear.


Asunto(s)
FN-kappa B , Ubiquitina , FN-kappa B/genética , FN-kappa B/metabolismo , Ubiquitina/metabolismo , Ubiquitina-Proteína Ligasas/genética , Ubiquitina-Proteína Ligasas/metabolismo , Transducción de Señal/fisiología , Mitocondrias/metabolismo , Ubiquitinación
2.
Biochim Biophys Acta Mol Cell Biol Lipids ; 1863(4): 433-446, 2018 Apr.
Artículo en Inglés | MEDLINE | ID: mdl-29360568

RESUMEN

Macrophages in adipose tissue contribute to inflammation and the development of insulin resistance in obesity. Exposure of macrophages to saturated fatty acids alters cell metabolism and activates pro-inflammatory signaling. How fatty acids influence macrophage mitochondrial dynamics is unclear. We investigated the mechanism of palmitate-induced mitochondrial fragmentation and its impact on inflammatory responses in primary human macrophages. Fatty acids, such as palmitate, caused mitochondrial fragmentation in human macrophages. Increased mitochondrial fragmentation was also observed in peritoneal macrophages from hyperlipidemic apolipoprotein E knockout mice. Fatty acid-induced mitochondrial fragmentation was independent of the fatty acid chain saturation and required dynamin-related protein 1 (DRP1). Mechanistically, mitochondrial fragmentation was regulated by incorporation of palmitate into mitochondrial phospholipids and their precursors. Palmitate-induced endoplasmic reticulum stress and loss of mitochondrial membrane potential did not contribute to mitochondrial fragmentation. Macrophages treated with palmitate maintained intact mitochondrial respiration and ATP levels. Pharmacological or genetic inhibition of DRP1 enhanced palmitate-induced mitochondrial ROS production, c-Jun phosphorylation, and inflammatory cytokine expression. Our results indicate that mitochondrial fragmentation is a protective mechanism attenuating inflammatory responses induced by palmitate in human macrophages.


Asunto(s)
Inflamación/metabolismo , Inflamación/patología , Macrófagos/metabolismo , Macrófagos/patología , Mitocondrias/metabolismo , Palmitatos/toxicidad , Animales , Línea Celular , Dinaminas , Estrés del Retículo Endoplásmico/efectos de los fármacos , GTP Fosfohidrolasas/metabolismo , Humanos , Macrófagos/efectos de los fármacos , Potencial de la Membrana Mitocondrial/efectos de los fármacos , Ratones , Proteínas Asociadas a Microtúbulos/metabolismo , Mitocondrias/efectos de los fármacos , Proteínas Mitocondriales/metabolismo
3.
J Biol Chem ; 291(1): 413-24, 2016 Jan 01.
Artículo en Inglés | MEDLINE | ID: mdl-26578520

RESUMEN

Pro-inflammatory cytokines secreted by adipose tissue macrophages (ATMs) contribute to chronic low-grade inflammation and obesity-induced insulin resistance. Recent studies have shown that adipose tissue hypoxia promotes an inflammatory phenotype in ATMs. However, our understanding of how hypoxia modulates the response of ATMs to free fatty acids within obese adipose tissue is limited. We examined the effects of hypoxia (1% O2) on the pro-inflammatory responses of human monocyte-derived macrophages to the saturated fatty acid palmitate. Compared with normoxia, hypoxia significantly increased palmitate-induced mRNA expression and protein secretion of IL-6 and IL-1ß. Although palmitate-induced endoplasmic reticulum stress and nuclear factor κB pathway activation were not enhanced by hypoxia, hypoxia increased the activation of JNK and p38 mitogen-activated protein kinase signaling in palmitate-treated cells. Inhibition of JNK blocked the hypoxic induction of pro-inflammatory cytokine expression, whereas knockdown of hypoxia-induced transcription factors HIF-1α and HIF-2α alone or in combination failed to reduce IL-6 and only modestly reduced IL-1ß gene expression in palmitate-treated hypoxic macrophages. Enhanced pro-inflammatory cytokine production and JNK activity under hypoxia were prevented by inhibiting reactive oxygen species generation. In addition, silencing of dual-specificity phosphatase 16 increased normoxic levels of IL-6 and IL-1ß and reduced the hypoxic potentiation in palmitate-treated macrophages. The secretome of hypoxic palmitate-treated macrophages promoted IL-6 and macrophage chemoattractant protein 1 expression in primary human adipocytes, which was sensitive to macrophage JNK inhibition. Our results reveal that the coexistence of hypoxia along with free fatty acids exacerbates macrophage-mediated inflammation.


Asunto(s)
Inflamación/patología , Macrófagos/patología , Palmitatos/farmacología , Acetilcisteína/farmacología , Adipocitos/efectos de los fármacos , Adipocitos/metabolismo , Animales , Factores de Transcripción con Motivo Hélice-Asa-Hélice Básico/metabolismo , Hipoxia de la Célula/efectos de los fármacos , Células Cultivadas , Medios de Cultivo Condicionados/farmacología , Citocinas/biosíntesis , Citocinas/genética , Fosfatasas de Especificidad Dual/metabolismo , Estrés del Retículo Endoplásmico/efectos de los fármacos , Humanos , Subunidad alfa del Factor 1 Inducible por Hipoxia/metabolismo , Mediadores de Inflamación/metabolismo , Macrófagos/efectos de los fármacos , Macrófagos/metabolismo , Ratones Endogámicos C57BL , Mitocondrias/efectos de los fármacos , Mitocondrias/metabolismo , Fosfatasas de la Proteína Quinasa Activada por Mitógenos/metabolismo , Proteínas Quinasas Activadas por Mitógenos/metabolismo , FN-kappa B/metabolismo , Compuestos Organofosforados/farmacología , Oxígeno/metabolismo , Fosforilación/efectos de los fármacos , Piperidinas/farmacología , Especies Reactivas de Oxígeno/metabolismo , Transducción de Señal/efectos de los fármacos
4.
Biochim Biophys Acta ; 1861(11): 1796-1807, 2016 11.
Artículo en Inglés | MEDLINE | ID: mdl-27614008

RESUMEN

Recent research considerably changed our knowledge how cellular metabolism affects the immune system. We appreciate that metabolism not only provides energy to immune cells, but also actively influences diverse immune cell phenotypes. Fatty acid metabolism, particularly mitochondrial fatty acid oxidation (FAO) emerges as an important regulator of innate and adaptive immunity. Catabolism of fatty acids also modulates the progression of disease, such as the development of obesity-driven insulin resistance and type II diabetes. Here, we summarize (i) recent developments in research how FAO modulates inflammatory signatures in macrophages in response to saturated fatty acids, and (ii) the role of FAO in regulating anti-inflammatory macrophage polarization. In addition, we define the contribution of AMP-activated protein kinase (AMPK) and peroxisome proliferator-activated receptors (PPARs), in controlling macrophage biology towards fatty acid metabolism and inflammation.


Asunto(s)
Polaridad Celular , Ácidos Grasos/metabolismo , Inflamación/metabolismo , Inflamación/patología , Macrófagos/metabolismo , Animales , Humanos , Modelos Biológicos , Oxidación-Reducción
5.
Stem Cells ; 34(8): 2236-48, 2016 08.
Artículo en Inglés | MEDLINE | ID: mdl-27145479

RESUMEN

Administration of bone marrow-derived mononuclear cells (BMC) may increase cardiac function after myocardial ischemia. However, the functional capacity of BMC derived from chronic heart failure (CHF) patients is significantly impaired. As modulation of the energy metabolism allows cells to match the divergent demands of the environment, we examined the regulation of energy metabolism in BMC from patients and healthy controls (HC). The glycolytic capacity of CHF-derived BMC is reduced compared to HC, whereas BMC of metabolically activated bone marrow after acute myocardial infarction reveal increased metabolism. The correlation of metabolic pathways with the functional activity of cells indicates an influence of metabolism on cell function. Reducing glycolysis without profoundly affecting ATP-production reversibly reduces invasion as well as colony forming capacity and abolishes proliferation of CD34(+) CD38(-) lin(-) hematopoietic stem and progenitor cells (HSPC). Ex vivo inhibition of glycolysis further reduced the pro-angiogenic activity of transplanted cells in a hind limb ischemia model in vivo. In contrast, inhibition of respiration, without affecting total ATP production, leads to a compensatory increase in glycolytic capacity correlating with increased colony forming capacity. Isolated CD34(+) , CXCR4(+) , and CD14(+) cells showed higher glycolytic activity compared to their negative counterparts. Metabolic activity was profoundly modulated by the composition of media used to store or culture BMC. This study provides first evidence that metabolic alterations influence the functional activity of human HSPC and BMC independent of ATP production. Changing the balance between respiration and glycolysis might be useful to improve patient-derived cells for clinical cardiac cell therapy. Stem Cells 2016;34:2236-2248.


Asunto(s)
Células de la Médula Ósea/citología , Células de la Médula Ósea/metabolismo , Insuficiencia Cardíaca/terapia , Isquemia Miocárdica/terapia , Animales , Respiración de la Célula , Ensayo de Unidades Formadoras de Colonias , Medios de Cultivo , Glucólisis , Insuficiencia Cardíaca/patología , Miembro Posterior/irrigación sanguínea , Miembro Posterior/patología , Humanos , Metabolómica , Ratones Desnudos , MicroARNs/metabolismo , Isquemia Miocárdica/patología , Neovascularización Fisiológica , Factor de Transcripción STAT5/metabolismo
6.
J Biol Chem ; 290(40): 24484-94, 2015 Oct 02.
Artículo en Inglés | MEDLINE | ID: mdl-26276392

RESUMEN

Macrophages respond to the Th2 cytokine IL-4 with elevated expression of arachidonate 15-lipoxygenase (ALOX15). Although IL-4 signaling elicits anti-inflammatory responses, 15-lipoxygenase may either support or inhibit inflammatory processes in a context-dependent manner. AMP-activated protein kinase (AMPK) is a metabolic sensor/regulator that supports an anti-inflammatory macrophage phenotype. How AMPK activation is linked to IL-4-elicited gene signatures remains unexplored. Using primary human macrophages stimulated with IL-4, we observed elevated ALOX15 mRNA and protein expression, which was attenuated by AMPK activation. AMPK activators, e.g. phenformin and aminoimidazole-4-carboxamide 1-ß-d-ribofuranoside inhibited IL-4-evoked activation of STAT3 while leaving activation of STAT6 and induction of typical IL-4-responsive genes intact. In addition, phenformin prevented IL-4-induced association of STAT6 and Lys-9 acetylation of histone H3 at the ALOX15 promoter. Activating AMPK abolished cellular production of 15-lipoxygenase arachidonic acid metabolites in IL-4-stimulated macrophages, which was mimicked by ALOX15 knockdown. Finally, pretreatment of macrophages with IL-4 for 48 h increased the mRNA expression of the proinflammatory cytokines IL-6, IL-12, CXCL9, and CXCL10 induced by subsequent stimulation with lipopolysaccharide. This response was attenuated by inhibition of ALOX15 or activation of AMPK during incubation with IL-4. In conclusion, limiting ALOX15 expression by AMPK may promote an anti-inflammatory phenotype of IL-4-stimulated human macrophages.


Asunto(s)
Proteínas Quinasas Activadas por AMP/metabolismo , Araquidonato 15-Lipooxigenasa/metabolismo , Regulación Enzimológica de la Expresión Génica , Interleucina-4/metabolismo , Macrófagos/enzimología , Antiinflamatorios/química , Quimiocina CXCL10/metabolismo , Quimiocina CXCL9/metabolismo , Perfilación de la Expresión Génica , Humanos , Inflamación/metabolismo , Subunidad p35 de la Interleucina-12/metabolismo , Interleucina-6/metabolismo , Monocitos/citología , Fagocitos/metabolismo , Fenotipo , ARN Interferente Pequeño/metabolismo , Factor de Transcripción STAT3/metabolismo , Factores de Tiempo
7.
Biochim Biophys Acta ; 1841(9): 1329-35, 2014 Sep.
Artículo en Inglés | MEDLINE | ID: mdl-24960101

RESUMEN

Macrophage polarization elicits various metabolic alterations which in turn influence the polarized phenotype. Activation of glycolytic metabolism accompanies and supports macrophage pro-inflammatory M1 polarization. In contrast, M2 polarization of murine macrophages in response to the Th2 cytokine interleukin-4 (IL-4) was linked to the up-regulation of mitochondrial oxidative metabolism and fatty acid oxidation (FAO), which was necessary for coining an IL-4-polarized phenotype. Here we investigated whether similar mechanisms operate in human macrophages stimulated with IL-4. IL-4 causes only moderate changes of mitochondrial oxidative metabolism and FAO, correlating with an unaltered expression of peroxisome proliferator-activated receptor-γ coactivator 1 α/ß (PGC-1α/ß), the master transcriptional regulators of mitochondrial biogenesis. Furthermore, attenuating FAO had no effect on IL-4-induced polarization-associated gene expression. Apparently, FAO is dispensable for IL-4-induced polarization of human macrophages, pointing to fundamental differences in the metabolic requirements of macrophage phenotype alterations between mice and humans.


Asunto(s)
Interleucina-4/farmacología , Macrófagos/efectos de los fármacos , Mitocondrias/efectos de los fármacos , Fosforilación Oxidativa/efectos de los fármacos , Animales , Proteínas Portadoras/genética , Proteínas Portadoras/metabolismo , Ácidos Grasos/agonistas , Ácidos Grasos/metabolismo , Regulación de la Expresión Génica , Humanos , Macrófagos/clasificación , Macrófagos/citología , Macrófagos/metabolismo , Ratones , Mitocondrias/metabolismo , Oxidación-Reducción , Coactivador 1-alfa del Receptor Activado por Proliferadores de Peroxisomas gamma , Cultivo Primario de Células , Proteínas de Unión al ARN , Transducción de Señal , Especificidad de la Especie , Factores de Transcripción/genética , Factores de Transcripción/metabolismo
8.
Diabetologia ; 57(5): 1067-77, 2014 May.
Artículo en Inglés | MEDLINE | ID: mdl-24488024

RESUMEN

AIMS/HYPOTHESIS: Saturated fatty acids (SFAs) such as palmitate activate inflammatory pathways and elicit an endoplasmic reticulum (ER) stress response in macrophages, thereby contributing to the development of insulin resistance linked to the metabolic syndrome. This study addressed the question of whether or not mitochondrial fatty acid ß-oxidation (FAO) affects macrophage responses to SFA. METHODS: We modulated the activity of carnitine palmitoyl transferase 1A (CPT1A) in macrophage-differentiated THP-1 monocytic cells using genetic or pharmacological approaches, treated the cells with palmitate and analysed the proinflammatory and ER stress signatures. RESULTS: To inhibit FAO, we created THP-1 cells with a stable knockdown (KD) of CPT1A and differentiated them to macrophages. Consequently, in CPT1A-silenced cells FAO was reduced. CPT1A KD in THP-1 macrophages increased proinflammatory signalling, cytokine expression and ER stress responses after palmitate treatment. In addition, in human primary macrophages CPT1A KD elevated palmitate-induced inflammatory gene expression. Pharmacological inhibition of FAO with etomoxir recapitulated the CPT1A KD phenotype. Conversely, overexpression of a malonyl-CoA-insensitive CPT1A M593S mutant reduced inflammatory and ER stress responses to palmitate in THP-1 macrophages. Macrophages with a CPT1A KD accumulated diacylglycerols and triacylglycerols after palmitate treatment, while ceramide accumulation remained unaltered. Moreover, lipidomic analysis of ER phospholipids revealed increased palmitate incorporation into phosphatidylethanolamine and phosphatidylserine classes associated with the CPT1A KD. CONCLUSIONS/INTERPRETATION: Our data indicate that FAO attenuates inflammatory and ER stress responses in SFA-exposed macrophages, suggesting an anti-inflammatory impact of drugs that activate FAO.


Asunto(s)
Estrés del Retículo Endoplásmico , Ácidos Grasos/metabolismo , Inflamación , Macrófagos/metabolismo , Oxígeno/metabolismo , Palmitatos/metabolismo , Carnitina O-Palmitoiltransferasa/metabolismo , Línea Celular Tumoral , Diglicéridos/metabolismo , Retículo Endoplásmico/metabolismo , Humanos , Resistencia a la Insulina , Microdominios de Membrana , Síndrome Metabólico/metabolismo , Mitocondrias/metabolismo , Triglicéridos/metabolismo
10.
Front Immunol ; 14: 1180488, 2023.
Artículo en Inglés | MEDLINE | ID: mdl-37153593

RESUMEN

Innate immune responses to pathogens, mediated by activation of pattern recognition receptors and downstream signal transduction cascades, trigger rapid transcriptional and epigenetic changes to support increased expression of pro-inflammatory cytokines and other effector molecules. Innate immune cells also rapidly rewire their metabolism. The most prominent metabolic alteration following innate immune activation is rapid up-regulation of glycolysis. In this mini-review, we summarize recent advances regarding the mechanisms of rapid glycolytic activation in innate immune cells, highlighting the relevant signaling components. We also discuss the impact of glycolytic activation on inflammatory responses, including the recently elucidated links of metabolism and epigenetics. Finally, we highlight unresolved mechanistic details of glycolytic activation and possible avenues of future research in this area.


Asunto(s)
Inmunidad Innata , Transducción de Señal , Receptores de Reconocimiento de Patrones/metabolismo , Citocinas/metabolismo , Glucólisis
11.
Arterioscler Thromb Vasc Biol ; 31(6): 1360-7, 2011 Jun.
Artículo en Inglés | MEDLINE | ID: mdl-21454809

RESUMEN

OBJECTIVE: Nitro-fatty acids (NO(2)-FAs) are emerging as a new class of cell signaling mediators. Because NO(2)-FAs are found in the vascular compartment and their impact on vascularization remains unknown, we aimed to investigate the role of NO(2)-FAs in angiogenesis. METHODS AND RESULTS: The effects of nitrolinoleic acid and nitrooleic acid were evaluated on migration of endothelial cell (EC) in vitro, EC sprouting ex vivo, and angiogenesis in the chorioallantoic membrane assay in vivo. At 10 µmol/L, both NO(2)-FAs induced EC migration and the formation of sprouts and promoted angiogenesis in vivo in an NO-dependent manner. In addition, NO(2)-FAs increased intracellular NO concentration, upregulated protein expression of the hypoxia inducible factor-1α (HIF-1α) transcription factor by an NO-mediated mechanism, and induced expression of HIF-1α target genes, such as vascular endothelial growth factor, glucose transporter-1, and adrenomedullin. Compared with typical NO donors such as spermine-NONOate and deta-NONOate, NO(2)-FAs were slightly less potent inducers of EC migration and HIF-1α expression. Short hairpin RNA-mediated knockdown of HIF-1α attenuated the induction of vascular endothelial growth factor mRNA expression and EC migration stimulated by NO(2)-FAs. CONCLUSION: Our data disclose a novel physiological role for NO(2)-FAs, indicating that these compounds induce angiogenesis in an NO-dependent mechanism via activation of HIF-1α.


Asunto(s)
Subunidad alfa del Factor 1 Inducible por Hipoxia/fisiología , Ácidos Linoleicos/farmacología , Neovascularización Fisiológica/efectos de los fármacos , Nitrocompuestos/farmacología , Ácidos Oléicos/farmacología , Animales , Movimiento Celular/efectos de los fármacos , Células Cultivadas , Células Endoteliales/efectos de los fármacos , Células Endoteliales/fisiología , Transportador de Glucosa de Tipo 1/genética , Humanos , Masculino , Óxido Nítrico/fisiología , Ratas , Ratas Wistar , Factor A de Crecimiento Endotelial Vascular/genética
12.
Cell Death Discov ; 8(1): 327, 2022 Jul 19.
Artículo en Inglés | MEDLINE | ID: mdl-35853860

RESUMEN

Compared to cancer cells, macrophages are inert to lipid peroxidation-triggered, iron-dependent cell death known as ferroptosis. Mechanisms underlying macrophage resistance towards ferroptosis are largely obscure. Here, we show that human primary macrophages respond to RSL3, a ferroptosis-inducing inhibitor of glutathione peroxidase 4, by upregulating mRNA expression of the iron transporter ferroportin. RSL3 induces lipid peroxidation, and both, lipid peroxidation as well as ferroportin induction were attenuated by liproxstatin-1, an inhibitor of lipid peroxidation and ferroptosis blocker. At the same time, system xc- inhibitor erastin fails to elicit lipid peroxidation or ferroportin expression. Ferroportin induction in response to RSL3 demands nuclear accumulation of the redox-sensitive transcription factor Nrf2 and downregulation of the transcriptional repressor BACH1. Silencing ferroportin or Nrf2 increases the cellular labile iron pool and lipid peroxidation, thereby sensitizing cells towards ferroptosis following RSL3 treatments. In contrast, silencing BACH1 decreases the labile iron pool and lipid peroxidation, enhancing macrophage resistance towards ferroptosis. Our findings reveal Nrf2, BACH1, and ferroportin as important regulators, protecting human macrophages against ferroptosis.

13.
Front Immunol ; 13: 906127, 2022.
Artículo en Inglés | MEDLINE | ID: mdl-36439127

RESUMEN

ATP-citrate lyase (ACLY) is a key enzyme provoking metabolic and epigenetic gene regulation. Molecularly, these functions are exerted by the provision of acetyl-coenzyme A, which is then used as a substrate for de novo lipogenesis or as an acetyl-group donor in acetylation reactions. It has been demonstrated that ACLY activity can be positively regulated via phosphorylation at serine 455 by Akt and protein kinase A. Nonetheless, the impact of phosphorylation on ACLY function in human myeloid cells is poorly understood. In this study we reconstituted ACLY knockout human monocytic THP-1 cells with a wild type ACLY as well as catalytically inactive H760A, and phosphorylation-deficient S455A mutants. Using these cell lines, we determined the impact of ACLY activity and phosphorylation on histone acetylation and pro-inflammatory gene expression in response to lipopolysaccharide (LPS). Our results show that ACLY serine 455 phosphorylation does not influence the proper enzymatic function of ACLY, since both, wild type ACLY and phosphorylation-deficient mutant, exhibited increased cell growth and histone acetylation as compared to cells with a loss of ACLY activity. Transcriptome analysis revealed enhanced expression of pro-inflammatory and interferon response genes in ACLY knockout and H760A THP-1 cells under unstimulated or LPS-treated conditions. At the same time, S455A ACLY-expressing cells showed a phenotype very similar to wild type cells. Contrary to ACLY knockout, pharmacological inhibition of ACLY in THP-1 cells or in primary human macrophages does not enhance LPS-triggered pro-inflammatory gene expression. Our data thus suggest that ACLY retains functionality in the absence of Akt/PKA-mediated phosphorylation in human myeloid cells. Furthermore, loss of ACLY activity may elicit long-term adaptive mechanisms, increasing inflammatory responses.


Asunto(s)
Histonas , Serina , Humanos , Acetilación , Fosforilación , Células THP-1 , Histonas/metabolismo , Serina/metabolismo , Proteínas Proto-Oncogénicas c-akt/metabolismo , Lipopolisacáridos/metabolismo , ATP Citrato (pro-S)-Liasa/metabolismo , Adenosina Trifosfato/metabolismo
14.
Clin Transl Med ; 12(12): e1068, 2022 Dec.
Artículo en Inglés | MEDLINE | ID: mdl-36504430

RESUMEN

BACKGROUND: Cytotoxic T lymphocytes take on a leading role in many immune-related diseases. They function as key effector immune cells fighting cancer cells, but they are also considerably involved in autoimmune diseases. Common to both situations, CD8+ T cells need to adapt their metabolism and effector function to the harsh and nutrient-deprived conditions of the disease-associated microenvironment. METHODS: We used an in vitro starvation as well as rapamycin treatment protocol mimicking nutrient deprivation to generate CD8Low versus CD8High T cells and performed FACS-Sorting followed by transcriptomic profiling of the cytotoxic T cell subsets. Prominent markers identified in the CD8Low versus the CD8High T cells were then used to investigate the presence of these cell subsets in immune-related human diseases. Employing cancer tissue microarrays and PhenOptics multispectral imaging as well as flow cytometry, we studied these CD8+ T cell subsets in cancer and relapsing-remitting multiple sclerosis patients. RESULTS: Starvation induced a decreased expression of CD8, yielding a CD8Low T cell subpopulation with an altered transcriptomic signature and reduced effector function. CD8Low T cell showed enhanced ST2L and IL6ST (CD130) expression compared to CD8High T cells which expressed elevated KLRD1 (CD94) and granzyme B levels within the tumour microenvironment (TME). Spatial analysis revealed the presence of CD8High T cells in close proximity to tumour cells, while the CD8Low T cells resided at the tumour boundaries. Importantly, the number of tumour-infiltrating CD8Low T lymphocytes correlated with a poor prognosis as well as with enhanced cancer progression in human mammary carcinoma. We also found a reduced frequency of CD8Low T lymphocytes in a cohort of relapse (disease active) multiple sclerosis patients compared to healthy subjects during immune cell starvation in vitro. CONCLUSIONS: In summary, our data show that functionally distinct cytotoxic T lymphocytes can be identified based on their expression of CD8. Indicating a more general role in CD8 T cell immunity, these cells may play opposing roles in the TME, and also in the pathophysiology of autoimmune diseases such as multiple sclerosis.


Asunto(s)
Enfermedades Autoinmunes , Esclerosis Múltiple , Humanos , Linfocitos T Citotóxicos , Esclerosis Múltiple/genética , Linfocitos T CD8-positivos , Recurrencia Local de Neoplasia , Microambiente Tumoral/genética
15.
Basic Res Cardiol ; 106(2): 205-15, 2011 Mar.
Artículo en Inglés | MEDLINE | ID: mdl-21116821

RESUMEN

Human monocytes/macrophages express the angiotensin-converting enzyme (ACE) but nothing is known about its role under physiological conditions. As adipose tissue contains resident macrophages that have been implicated in the generation of insulin resistance in expanding fat mass, we determined whether adipocytes release factors that affect ACE expression and function in monocytes. Incubation of human monocyte-derived macrophages with conditioned medium from freshly isolated human adipocytes (BMI = 25.4 ± 0.96) resulted in a 4-fold increase in ACE expression. The effect was insensitive to denaturation and different proteases but abolished after lipid extraction. mRNA levels of the major histocompatibility complex class II protein increased in parallel with ACE, whereas the expression of tumor necrosis factor-α (TNF-α), monocyte chemoattractant protein-1 (MCP-1), interleukin (IL)-6, and cyclooxygenase-2 decreased. As a consequence of the reduction in MCP-1, monocyte recruitment was also attenuated. Moreover, adipocyte-conditioned medium prevented the interferon (IFN)-γ induced formation of TNF-α, IL-6, and MCP-1, all markers of classically-activated (M1 type) macrophages. The decrease in cytokine expression in adipocyte-conditioned medium-treated macrophages was sensitive to ACE silencing by small interfering RNA (siRNA). Accordingly, ACE overexpression in THP-1 cells mimicked the effect of adipocyte-conditioned medium. In both cell types, ACE inhibition failed to affect the changes induced by adipocyte conditioned-medium treatment and ACE overexpression. Thus, the modulation of macrophage polarization by ACE appears to be mediated independently of enzyme activity, probably via intracellular signaling. Interestingly, human macrophage ACE expression was also upregulated by IL-4 and IL-13, which promote the "alternative" activation of macrophages and decreased by LPS and IFN-γ. Mechanistically, adipocyte-conditioned medium stimulated the phosphorylation of the AMP-activated protein kinase and AMPK inhibition prevented the increase in ACE expression. Moreover, ACE expression was reduced in spleen derived-monocytes from AMPKα1(-/-) mice versus their wild-type littermates. These data indicate that mature adipocytes modulate the expression profile of macrophages by releasing lipid mediators that increase ACE expression via AMPK. This prevents the pro-inflammatory cytokine production by macrophages.


Asunto(s)
Tejido Adiposo/metabolismo , Metabolismo de los Lípidos , Macrófagos/metabolismo , Peptidil-Dipeptidasa A/metabolismo , Animales , Línea Celular , Células Cultivadas , Medios de Cultivo Condicionados , Humanos , Macrófagos/citología , Ratones , Ratones Transgénicos , Monocitos/metabolismo , Fenotipo , Transducción de Señal
16.
Blood ; 114(10): 2140-8, 2009 Sep 03.
Artículo en Inglés | MEDLINE | ID: mdl-19549990

RESUMEN

Macrophages infiltrating solid tumors exhibit a tumor-supporting phenotype and are critical for tumor development. Little is known which tumor-derived signal provokes this phenotype shift and how these signals are interpreted in macrophages to support tumor growth. We used the supernatant of apoptotic cells and noticed transcriptional, nuclear factor of activated T cells-dependent up-regulation of hypoxia-inducible factor (HIF)-1alpha mRNA, subsequent protein expression, and HIF-1 activity. Blocking calcineurin with cyclosporine A attenuated nuclear factor of activated T cells binding during electrophoretic mobility shift assay analysis and circumvented the HIF-1alpha mRNA increase. Knockdown experiments, receptor analysis, and antibody neutralization pointed to sphingosine-1-phosphate and transforming growth factor-beta as the initiators of the HIF-1 response. The use of macrophages from conditional HIF-1alpha knockout mice revealed that macrophages, under the impact of apoptotic cell supernatants, use HIF-1 to produce factors that induce CD31 expression in murine embryonic stem cells. Our study supports the notion that soluble factors produced from apoptotic tumor cells activate the HIF-1 system under normoxia in macrophages to enhance their tumor-promoting capacity by, for example, releasing vascular endothelial growth factor. This shows the importance of HIF-1-elicited responses in regulatory macrophages under normoxia.


Asunto(s)
Medios de Cultivo Condicionados/farmacología , Subunidad alfa del Factor 1 Inducible por Hipoxia/metabolismo , Lisofosfolípidos/metabolismo , Macrófagos/metabolismo , Neoplasias/metabolismo , Esfingosina/análogos & derivados , Factor de Crecimiento Transformador beta/metabolismo , Animales , Apoptosis , Calcineurina/metabolismo , Inhibidores de la Calcineurina , Ciclosporina/farmacología , Regulación de la Expresión Génica/efectos de los fármacos , Humanos , Subunidad alfa del Factor 1 Inducible por Hipoxia/genética , Inmunosupresores/farmacología , Células Jurkat , Macrófagos/patología , Ratones , Ratones Noqueados , Factores de Transcripción NFATC/metabolismo , Neoplasias/patología , Molécula-1 de Adhesión Celular Endotelial de Plaqueta/biosíntesis , ARN Mensajero/metabolismo , Esfingosina/metabolismo , Factor A de Crecimiento Endotelial Vascular/biosíntesis
17.
Arterioscler Thromb Vasc Biol ; 30(2): 313-20, 2010 Feb.
Artículo en Inglés | MEDLINE | ID: mdl-19948841

RESUMEN

BACKGROUND AND PURPOSE: Peroxisome proliferator-activated receptors (PPARs) are ligand-activated transcription factors modulating metabolic and inflammatory responses of phagocytes to stimuli such as fatty acids and their metabolites. We studied the role of PPARs in macrophages exposed to low-density lipoprotein (LDL) modified by secretory phospholipase A(2) (PLA). METHODS AND RESULTS: By analyzing PPAR ligand-binding domain luciferase reporter activation, we observed that PLA-LDL transactivates PPARalpha and PPARdelta, but not PPARgamma. We confirmed that PLA-LDL induced PPAR response element reporter activation by endogenous PPARalpha and PPARdelta in human THP-1 macrophages. By using THP-1 cells with a stable knockdown of PPARalpha and PPARdelta, we showed that PLA-LDL-activated PPARdelta altered macrophage gene expression related to lipid metabolism and lipid droplet formation. Although PPARalpha/delta silencing did not affect cholesterol and triglyceride accumulation in PLA-LDL-treated macrophages, PPARdelta activation by PLA-LDL attenuated macrophage inflammatory gene expression induced by interferon gamma and lipopolysaccharide. CONCLUSIONS: PPARdelta activation by PLA-LDL does not influence lipid accumulation in PLA-LDL-treated macrophages. However, it attenuates macrophage inflammatory responses, thus contributing to an anti-inflammatory cell phenotype.


Asunto(s)
Lipoproteínas LDL/metabolismo , Macrófagos/enzimología , Receptores Activados del Proliferador del Peroxisoma/metabolismo , Fosfolipasas A2 Secretoras/metabolismo , Animales , Sitios de Unión , Línea Celular , Colesterol/metabolismo , Ácidos Grasos no Esterificados/metabolismo , Humanos , Interferón gamma/metabolismo , Metabolismo de los Lípidos/genética , Lipopolisacáridos/farmacología , Macrófagos/efectos de los fármacos , Macrófagos/inmunología , Ratones , PPAR alfa/metabolismo , PPAR delta/metabolismo , PPAR gamma/metabolismo , Receptores Activados del Proliferador del Peroxisoma/efectos de los fármacos , Receptores Activados del Proliferador del Peroxisoma/genética , Interferencia de ARN , ARN Mensajero/metabolismo , Secuencias Reguladoras de Ácidos Nucleicos , Activación Transcripcional , Transfección , Triglicéridos/metabolismo
18.
Cancers (Basel) ; 13(5)2021 Feb 25.
Artículo en Inglés | MEDLINE | ID: mdl-33668835

RESUMEN

The transcription factor p53 has well-recognized roles in regulating cell cycle, DNA damage repair, cell death, and metabolism. It is an important tumor suppressor and pharmacological activation of p53 by interrupting its interaction with the ubiquitin E3 ligase mouse double minute 2 homolog (MDM2) is actively explored for anti-tumor therapies. In immune cells, p53 modulates inflammatory responses, but the impact of p53 on macrophages remains incompletely understood. In this study, we used the MDM2 antagonist idasanutlin (RG7388) to investigate the responses of primary human macrophages to pharmacological p53 activation. Idasanutlin induced a robust p53-dependent transcriptional signature in macrophages, including several pro-apoptotic genes. However, idasanutlin did not generally sensitize macrophages to apoptosis, except for an enhanced response to a Fas-stimulating antibody. In fully differentiated macrophages, idasanutlin did not affect pro-inflammatory gene expression induced by toll-like receptor 4 (TLR4), TLR3, and TLR7/8 agonists, but inhibited interleukin-4-induced macrophage polarization. However, when present during monocyte to macrophage differentiation, idasanutlin attenuated inflammatory responses towards activation of TLR4 and TLR7/8 by low doses of lipopolysaccharide or resiquimod (R848). This was accompanied by a reduced expression of CD14, TLR7, and TLR8 in macrophages differentiated in the presence of idasanutlin. Our data suggest anti-inflammatory effects of pharmacological p53 activation in differentiating human macrophages.

19.
Front Immunol ; 12: 632526, 2021.
Artículo en Inglés | MEDLINE | ID: mdl-33679780

RESUMEN

Studies over the past decade have revealed that metabolism profoundly influences immune responses. In particular, metabolism causes epigenetic regulation of gene expression, as a growing number of metabolic intermediates are substrates for histone post-translational modifications altering chromatin structure. One of these substrates is acetyl-coenzyme A (CoA), which donates an acetyl group for histone acetylation. Cytosolic acetyl-CoA is also a critical substrate for de novo synthesis of fatty acids and sterols necessary for rapid cellular growth. One of the main enzymes catalyzing cytosolic acetyl-CoA formation is ATP-citrate lyase (ACLY). In addition to its classical function in the provision of acetyl-CoA for de novo lipogenesis, ACLY contributes to epigenetic regulation through histone acetylation, which is increasingly appreciated. In this review we explore the current knowledge of ACLY and acetyl-CoA in mediating innate and adaptive immune responses. We focus on the role of ACLY in supporting de novo lipogenesis in immune cells as well as on its impact on epigenetic alterations. Moreover, we summarize alternative sources of acetyl-CoA and their contribution to metabolic and epigenetic regulation in cells of the immune system.


Asunto(s)
ATP Citrato (pro-S)-Liasa/inmunología , Inmunidad Adaptativa , Inmunidad Innata , ATP Citrato (pro-S)-Liasa/metabolismo , Acetilcoenzima A/metabolismo , Acetilación , Epigénesis Genética , Ácidos Grasos/metabolismo , Histonas/metabolismo , Humanos , Lipogénesis
20.
Front Immunol ; 12: 637778, 2021.
Artículo en Inglés | MEDLINE | ID: mdl-34025647

RESUMEN

Efferocytosis is critical for tissue homeostasis, as its deregulation is associated with several autoimmune pathologies. While engulfing apoptotic cells, phagocytes activate transcription factors, such as peroxisome proliferator-activated receptors (PPAR) or liver X receptors (LXR) that orchestrate metabolic, phagocytic, and inflammatory responses towards the ingested material. Coordination of these transcription factors in efferocytotic human macrophages is not fully understood. In this study, we evaluated the transcriptional profile of macrophages following the uptake of apoptotic Jurkat T cells using RNA-seq analysis. Results indicated upregulation of PPAR and LXR pathways but downregulation of sterol regulatory element-binding proteins (SREBP) target genes. Pharmacological inhibition and RNA interference pointed to LXR and PPARδ as relevant transcriptional regulators, while PPARγ did not substantially contribute to gene regulation. Mechanistically, lysosomal digestion and lysosomal acid lipase (LIPA) were required for PPAR and LXR activation, while PPARδ activation also demanded an active lysosomal phospholipase A2 (PLA2G15). Pharmacological interference with LXR signaling attenuated ABCA1-dependent cholesterol efflux from efferocytotic macrophages, but suppression of inflammatory responses following efferocytosis occurred independently of LXR and PPARδ. These data provide mechanistic details on LXR and PPARδ activation in efferocytotic human macrophages.


Asunto(s)
Apoptosis/fisiología , Receptores X del Hígado/metabolismo , Macrófagos/metabolismo , PPAR gamma/metabolismo , Fagocitosis/fisiología , Transportador 1 de Casete de Unión a ATP/metabolismo , Aciltransferasas/metabolismo , Línea Celular Tumoral , Colesterol/metabolismo , Perfilación de la Expresión Génica , Regulación de la Expresión Génica , Humanos , Células Jurkat , Receptores X del Hígado/genética , Lisosomas/metabolismo , PPAR gamma/genética , Fosfolipasas A2/metabolismo , Piruvato Deshidrogenasa Quinasa Acetil-Transferidora/metabolismo , Interferencia de ARN , ARN Interferente Pequeño/genética , Proteínas de Unión a los Elementos Reguladores de Esteroles/metabolismo , Transcripción Genética/genética , Transcriptoma/genética
SELECCIÓN DE REFERENCIAS
DETALLE DE LA BÚSQUEDA