RESUMEN
Psoriasis is characterized by keratinocyte (KC) hyperproliferation and inflammatory cell infiltration, but the mechanisms remain unclear. In an imiquimod-induced mouse psoriasiform model, p38 activity is significantly elevated in KCs and p38α specific deletion in KCs ameliorates skin inflammation. p38α signaling promotes KC proliferation and psoriasis-related proinflammatory gene expression during psoriasis development. Mechanistically, p38α enhances KC proliferation and production of inflammatory cytokines and chemokines by activating STAT3. While p38α signaling in KCs does not affect the expression of IL-23 and IL-17, it substantially amplifies the IL-23/IL-17 pathogenic axis in psoriasis. The therapeutic effect of IL-17 neutralization is associated with decreased p38 and STAT3 activities in KCs and targeting the p38α-STAT3 axis in KCs ameliorates the severity of psoriasis. As IL-17 also highly activates p38 and STAT3 in KCs, our findings reveal a sustained signaling circuit important for psoriasis development, highlighting p38α-STAT3 axis as an important target for psoriasis treatment.
Asunto(s)
Proliferación Celular , Citocinas , Queratinocitos , Proteína Quinasa 14 Activada por Mitógenos , Psoriasis , Factor de Transcripción STAT3 , Psoriasis/metabolismo , Psoriasis/genética , Psoriasis/patología , Factor de Transcripción STAT3/metabolismo , Factor de Transcripción STAT3/genética , Queratinocitos/metabolismo , Animales , Ratones , Proteína Quinasa 14 Activada por Mitógenos/metabolismo , Proteína Quinasa 14 Activada por Mitógenos/genética , Citocinas/metabolismo , Regulación hacia Abajo , Ratones Noqueados , Interleucina-17/metabolismo , Interleucina-17/genética , Ratones Endogámicos C57BL , Modelos Animales de Enfermedad , Transducción de Señal , Humanos , ImiquimodRESUMEN
Heart failure is a leading cause of mortality in developed countries. Cell death is a key player in the development of heart failure. Calcium-independent phospholipase A2ß (iPLA2ß) produces lipid mediators by catalyzing lipids and induces nuclear shrinkage in caspase-independent cell death. Here, we show that lysophosphatidylserine generated by iPLA2ß induces necrotic cardiomyocyte death, as well as contractile dysfunction mediated through its receptor, G protein-coupled receptor 34 (GPR34). Cardiomyocyte-specific iPLA2ß-deficient male mice were subjected to pressure overload. While control mice showed left ventricular systolic dysfunction with necrotic cardiomyocyte death, iPLA2ß-deficient mice preserved cardiac function. Lipidomic analysis revealed a reduction of 18:0 lysophosphatidylserine in iPLA2ß-deficient hearts. Knockdown of Gpr34 attenuated 18:0 lysophosphatidylserine-induced necrosis in neonatal male rat cardiomyocytes, while the ablation of Gpr34 in male mice reduced the development of pressure overload-induced cardiac remodeling. Thus, the iPLA2ß-lysophosphatidylserine-GPR34-necrosis signaling axis plays a detrimental role in the heart in response to pressure overload.
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Insuficiencia Cardíaca , Miocitos Cardíacos , Ratas , Ratones , Masculino , Animales , Miocitos Cardíacos/metabolismo , Insuficiencia Cardíaca/metabolismo , Necrosis/metabolismo , Receptores Acoplados a Proteínas G/genética , Receptores Acoplados a Proteínas G/metabolismo , Remodelación Ventricular , Ratones NoqueadosRESUMEN
Sepsis is a life-threatening syndrome, and its associated mortality is increased when cardiac dysfunction and damage (septic cardiomyopathy [SCM]) occur. Although inflammation is involved in the pathophysiology of SCM, the mechanism of how inflammation induces SCM in vivo has remained obscure. NLRP3 inflammasome is a critical component of the innate immune system that activates caspase-1 (Casp1) and causes the maturation of IL-1ß and IL-18 as well as the processing of gasdermin D (GSDMD). Here, we investigated the role of the NLRP3 inflammasome in a murine model of lipopolysaccharide (LPS)-induced SCM. LPS injection induced cardiac dysfunction, damage, and lethality, which was significantly prevented in NLRP3-/- mice, compared to wild-type (WT) mice. LPS injection upregulated mRNA levels of inflammatory cytokines (Il6, Tnfa, and Ifng) in the heart, liver, and spleen of WT mice, and this upregulation was prevented in NLRP3-/- mice. LPS injection increased plasma levels of inflammatory cytokines (IL-1ß, IL-18, and TNF-α) in WT mice, and this increase was markedly inhibited in NLRP3-/- mice. LPS-induced SCM was also prevented in Casp1/11-/- mice, but not in Casp11mt, IL-1ß-/-, IL-1α-/-, or GSDMD-/- mice. Notably, LPS-induced SCM was apparently prevented in IL-1ß-/- mice transduced with adeno-associated virus vector expressing IL-18 binding protein (IL-18BP). Furthermore, splenectomy, irradiation, or macrophage depletion alleviated LPS-induced SCM. Our findings demonstrate that the cross-regulation of NLRP3 inflammasome-driven IL-1ß and IL-18 contributes to the pathophysiology of SCM and provide new insights into the mechanism underlying the pathogenesis of SCM.
Asunto(s)
Cardiomiopatías , Inflamasomas , Interleucina-18 , Interleucina-1beta , Proteína con Dominio Pirina 3 de la Familia NLR , Animales , Ratones , Cardiomiopatías/genética , Caspasa 1/genética , Caspasa 1/metabolismo , Citocinas , Inflamasomas/metabolismo , Inflamación , Interleucina-18/genética , Interleucina-1beta/metabolismo , Lipopolisacáridos/efectos adversos , Ratones Endogámicos C57BL , Proteína con Dominio Pirina 3 de la Familia NLR/genética , Proteína con Dominio Pirina 3 de la Familia NLR/metabolismoRESUMEN
BACKGROUND: Although hypercholesterolemia reportedly counteracts lymphocyte trafficking across lymphatic vessels, the roles of lymphatic endothelial cells (LECs) in the lymphocyte regulations remain unclear. Previous studies showed that calpain-an intracellular modulatory protease-interferes with leukocyte dynamics in the blood microcirculation and is associated with hypercholesterolemic dysfunction in vascular endothelial cells. METHODS: This study investigated whether the calpain systems in LECs associate with the LEC-lymphocyte interaction under hypercholesterolemia using gene-targeted mice. RESULTS: Lipidomic analysis in hypercholesterolemic mice showed that several lysophospholipids, including lysophosphatidic acid, accumulated in the lymphatic environment. Lysophosphatidic acid enables the potentiation of calpain systems in cultured LECs, which limits their ability to stabilize regulatory T cells (Treg) without altering Th1/Th2 (T helper type1/2) subsets. This occurs via the proteolytic degradation of MEKK1 (mitogen-activated protein kinase kinase kinase 1) and the subsequent inhibition of TGF (transforming growth factor)-ß1 production in LECs. Targeting calpain systems in LECs expanded Tregs in the blood circulation and reduced aortic atherosclerosis in hypercholesterolemic mice, concomitant with the reduction of proinflammatory macrophages in the lesions. Treg expansion in the blood circulation and atheroprotection in calpain-targeted mice was prevented by the administration of TGF-ß type-I receptor inhibitor. Moreover, lysophosphatidic acid-induced calpain overactivation potentiated the IL (interleukin)-18/NF-κB (nuclear factor κB)/VCAM1 (vascular cell adhesion molecule 1) axis in LECs, thereby inhibiting lymphocyte mobility on the cells. Indeed, VCAM1 in LECs was upregulated in hypercholesterolemic mice and human cases of coronary artery disease. Neutralization of VCAM1 or targeting LEC calpain systems recovered afferent Treg transportation via lymphatic vessels in mice. CONCLUSIONS: Calpain systems in LECs have a key role in controlling Treg stability and trafficking under hypercholesterolemia.
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Hipercolesterolemia , Vasos Linfáticos , Ratones , Humanos , Animales , Células Endoteliales/metabolismo , Linfocitos T Reguladores/metabolismo , Calpaína/metabolismo , Hipercolesterolemia/complicaciones , Hipercolesterolemia/genética , Hipercolesterolemia/metabolismo , Vasos Linfáticos/metabolismo , FN-kappa B/metabolismoRESUMEN
Estrogen and progesterone specify the establishment of uterine receptivity mainly through their respective nuclear receptors, ER and PR. PR is transcriptionally induced by estrogen-ER signaling in the endometrium, but how the protein homeostasis of PR in the endometrium is regulated remains elusive. Here, we demonstrated that the uterine-selective depletion of P38α derails normal uterine receptivity ascribed to the dramatic down-regulation of PR protein and disordered progesterone responsiveness in the uterine stromal compartment, leading to defective implantation and female infertility. Specifically, Ube3c, an HECT family E3 ubiquitin ligase, targets PR for polyubiquitination and thus proteasome degradation in the absence of P38α. Moreover, we discovered that P38α restrains the polyubiquitination activity of Ube3c toward PR by phosphorylating the Ube3c at serine741 . In summary, we provided genetic evidence for the regulation of PR protein stability in the endometrium by P38α and identified Ube3c, whose activity was modulated by P38α-mediated phosphorylation, as an E3 ubiquitin ligase for PR in the uterus.
Asunto(s)
Implantación del Embrión , Sistema de Señalización de MAP Quinasas , Proteína Quinasa 14 Activada por Mitógenos , Progesterona , Útero , Animales , Implantación del Embrión/fisiología , Endometrio/metabolismo , Femenino , Infertilidad Femenina , Proteína Quinasa 14 Activada por Mitógenos/metabolismo , Fosforilación , Progesterona/metabolismo , Receptores de Progesterona/metabolismo , Ubiquitina-Proteína Ligasas/genética , Ubiquitina-Proteína Ligasas/metabolismo , Ubiquitinación , Útero/enzimología , Útero/metabolismoRESUMEN
Dendritic cells (DCs) play a critical role in controlling T helper 2 (Th2) cell-dependent diseases, but the signaling mechanism that triggers this function is not fully understood. We showed that p38α activity in DCs was decreased upon HDM stimulation and dynamically regulated by both extrinsic signals and Th2-instructive cytokines. p38α-specific deletion in cDC1s but not in cDC2s or macrophages promoted Th2 responses under HDM stimulation. Further study showed that p38α in cDC1s regulated Th2-cell differentiation by modulating the MK2-c-FOS-IL-12 axis. Importantly, crosstalk between p38α-dependent DCs and Th2 cells occurred during the sensitization phase, not the effector phase, and was conserved between mice and humans. Our results identify p38α signaling as a central pathway in DCs that integrates allergic and parasitic instructive signals with Th2-instructive cytokines from the microenvironment to regulate Th2-cell differentiation and function, and this finding may offer a novel strategy for the treatment of allergic diseases and parasitic infection.
Asunto(s)
Hipersensibilidad , Proteína Quinasa 14 Activada por Mitógenos/metabolismo , Células Th2 , Animales , Diferenciación Celular , Citocinas/metabolismo , Células Dendríticas/metabolismo , Humanos , Hipersensibilidad/metabolismo , Inflamación/metabolismo , Ratones , Células Th2/metabolismoRESUMEN
Free amino acids that accumulate in the plasma of patients with diabetes and obesity influence lipid metabolism and protein synthesis in the liver. The stress-inducible intracellular protease calpain proteolyzes various substrates in vascular endothelial cells (ECs), although its contribution to the supply of free amino acids in the liver microenvironment remains enigmatic. In the present study, we showed that calpains are associated with free amino acid production in cultured ECs. Furthermore, conditioned media derived from calpain-activated ECs facilitated the phosphorylation of ribosomal protein S6 kinase (S6K) and de novo lipogenesis in hepatocytes, which were abolished by the amino acid transporter inhibitor, JPH203, and the mammalian target of rapamycin complex 1 inhibitor, rapamycin. Meanwhile, calpain-overexpressing capillary-like ECs were observed in the livers of high-fat diet-fed mice. Conditional KO of EC/hematopoietic Capns1, which encodes a calpain regulatory subunit, diminished levels of branched-chain amino acids in the hepatic microenvironment without altering plasma amino acid levels. Concomitantly, conditional KO of Capns1 mitigated hepatic steatosis without normalizing body weight and the plasma lipoprotein profile in an amino acid transporter-dependent manner. Mice with targeted Capns1 KO exhibited reduced phosphorylation of S6K and maturation of lipogenic factor sterol regulatory element-binding protein 1 in hepatocytes. Finally, we show that bone marrow transplantation negated the contribution of hematopoietic calpain systems. We conclude that overactivation of calpain systems may be responsible for the production of free amino acids in ECs, which may be sufficient to potentiate S6K/sterol regulatory element-binding protein 1-induced lipogenesis in surrounding hepatocytes.
Asunto(s)
Calpaína , Hígado Graso , Aminoácidos/metabolismo , Animales , Calpaína/genética , Calpaína/metabolismo , Células Endoteliales/metabolismo , Hígado Graso/metabolismo , Humanos , Lipogénesis , Hígado/metabolismo , Mamíferos/metabolismo , Ratones , Ratones Endogámicos C57BL , Obesidad/metabolismo , Proteínas Quinasas S6 Ribosómicas/metabolismo , Proteína 1 de Unión a los Elementos Reguladores de Esteroles/metabolismoRESUMEN
Adipose tissue-resident T cells play vital roles in regulating inflammation and metabolism in obesity, but the underlying mechanisms remain unclear. Here, we show that high-fat diet (HFD) feeding enhances p38 activity in adipose-resident T cells. T cell-specific deletion of p38α, an essential subunit of p38 expressed in most immune cells, protected mice from HFD-induced obesity, hepatic steatosis, adipose tissue inflammation, and insulin resistance. Mice with p38α deletion in T cells exhibited higher energy expenditure. Mechanistically, p38α promoted T-cell glycolysis through mechanistic target of rapamycin signaling, leading to enhanced Th1 differentiation. Accordingly, genetic deletion of p38α alleviated ongoing diet-induced obesity. Unexpectedly, p38α signaling in T cells promoted adipose tissue senescence during obesity and aging. Taken together, our results identify p38α in T cells as an essential regulator of obesity, insulin resistance, and adipose tissue senescence, and p38α may be a therapeutic target for obese- or aging-associated diseases.
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Resistencia a la Insulina , Tejido Adiposo/metabolismo , Animales , Dieta Alta en Grasa/efectos adversos , Inflamación/metabolismo , Resistencia a la Insulina/fisiología , Ratones , Ratones Endogámicos C57BL , Ratones Noqueados , Obesidad/genética , Linfocitos T/metabolismoRESUMEN
Heart failure has high morbidity and mortality in the developed countries. Autophagy is important for the quality control of proteins and organelles in the heart. Rubicon (Run domain Beclin-1-interacting and cysteine-rich domain-containing protein) has been identified as a potent negative regulator of autophagy and endolysosomal trafficking. The aim of this study was to investigate the in vivo role of Rubicon-mediated autophagy and endosomal trafficking in the heart. We generated cardiomyocyte-specific Rubicon-deficient mice and subjected the mice to pressure overload by means of transverse aortic constriction. Rubicon-deficient mice showed heart failure with left ventricular dilatation, systolic dysfunction and lung congestion one week after pressure overload. While autophagic activity was unchanged, the protein amount of beta-1 adrenergic receptor was decreased in the pressure-overloaded Rubicon-deficient hearts. The increases in heart rate and systolic function by beta-1 adrenergic stimulation were significantly attenuated in pressure-overloaded Rubicon-deficient hearts. In isolated rat neonatal cardiomyocytes, the downregulation of the receptor by beta-1 adrenergic agonist was accelerated by knockdown of Rubicon through the inhibition of recycling of the receptor. Taken together, Rubicon protects the heart from pressure overload. Rubicon maintains the intracellular recycling of beta-1 adrenergic receptor, which might contribute to its cardioprotective effect.
Asunto(s)
Proteínas Relacionadas con la Autofagia , Insuficiencia Cardíaca , Receptores Adrenérgicos beta 1 , Animales , Masculino , Ratones , Autofagia/fisiología , Proteínas Relacionadas con la Autofagia/genética , Proteínas Relacionadas con la Autofagia/metabolismo , Células Cultivadas , Endosomas/metabolismo , Insuficiencia Cardíaca/genética , Insuficiencia Cardíaca/metabolismo , Péptidos y Proteínas de Señalización Intracelular/genética , Péptidos y Proteínas de Señalización Intracelular/metabolismo , Miocitos Cardíacos/metabolismo , Ratas Wistar , Receptores Adrenérgicos beta 1/metabolismoRESUMEN
BACKGROUND: During the development of heart failure, a fetal cardiac gene program is reactivated and accelerates pathological cardiac remodeling. We previously reported that a transcriptional repressor, NRSF (neuron restrictive silencer factor), suppresses the fetal cardiac gene program, thereby maintaining cardiac integrity. The underlying molecular mechanisms remain to be determined, however. METHODS: We aim to elucidate molecular mechanisms by which NRSF maintains normal cardiac function. We generated cardiac-specific NRSF knockout mice and analyzed cardiac gene expression profiles in those mice and mice cardiac-specifically expressing a dominant-negative NRSF mutant. RESULTS: We found that cardiac expression of Gαo, an inhibitory G protein encoded in humans by GNAO1, is transcriptionally regulated by NRSF and is increased in the ventricles of several mouse models of heart failure. Genetic knockdown of Gnao1 ameliorated the cardiac dysfunction and prolonged survival rates in these mouse heart failure models. Conversely, cardiac-specific overexpression of GNAO1 in mice was sufficient to induce cardiac dysfunction. Mechanistically, we observed that increasing Gαo expression increased surface sarcolemmal L-type Ca2+ channel activity, activated CaMKII (calcium/calmodulin-dependent kinase-II) signaling, and impaired Ca2+ handling in ventricular myocytes, which led to cardiac dysfunction. CONCLUSIONS: These findings shed light on a novel function of Gαo in the regulation of cardiac Ca2+ homeostasis and systolic function and suggest Gαo may be an effective therapeutic target for the treatment of heart failure.
Asunto(s)
Subunidades alfa de la Proteína de Unión al GTP Gi-Go/metabolismo , Insuficiencia Cardíaca/metabolismo , Miocitos Cardíacos/metabolismo , Proteínas Represoras/metabolismo , Animales , Canales de Calcio Tipo L/metabolismo , Señalización del Calcio , Proteína Quinasa Tipo 2 Dependiente de Calcio Calmodulina/metabolismo , Células Cultivadas , Subunidades alfa de la Proteína de Unión al GTP Gi-Go/genética , Ventrículos Cardíacos/citología , Ventrículos Cardíacos/metabolismo , Homeostasis , Ratones , Ratones Endogámicos C57BL , Proteínas Represoras/genéticaRESUMEN
Heart failure is a major public health problem, and inflammation is involved in its pathogenesis. Inflammatory Ly6Chi monocytes accumulate in mouse hearts after pressure overload and are detrimental to the heart; however, the types of cells that drive inflammatory cell recruitment remain uncertain. Here, we showed that a distinct subset of mouse cardiac fibroblasts became activated by pressure overload and recruited Ly6Chi monocytes to the heart. Single-cell sequencing analysis revealed that a subset of cardiac fibroblasts highly expressed genes transcriptionally activated by the transcription factor NF-κB, as well as C-C motif chemokine ligand 2 (Ccl2) mRNA, which encodes a major factor in Ly6Chi monocyte recruitment. The deletion of the NF-κB activator IKKß in activated cardiac fibroblasts attenuated Ly6Chi monocyte recruitment and preserved cardiac function in mice subjected to pressure overload. Pseudotime analysis indicated two single-branch trajectories from quiescent fibroblasts into inflammatory fibroblasts and myofibroblasts. Our results provide insight into the mechanisms underlying cardiac inflammation and fibroblast-mediated inflammatory responses that could be therapeutically targeted to treat heart failure.
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Monocitos , FN-kappa B , Animales , Fibroblastos/metabolismo , Regulación de la Expresión Génica , Ratones , Ratones Endogámicos C57BL , Monocitos/metabolismo , FN-kappa B/genética , FN-kappa B/metabolismo , Transducción de SeñalRESUMEN
Hematopoietic stem cells (HSCs) and their progeny sustain lifetime hematopoiesis. Aging alters HSC function, number, and composition and increases risk of hematological malignancies, but how these changes occur in HSCs remains unclear. Signaling via p38 mitogen-activated kinase (p38MAPK) has been proposed as a candidate mechanism underlying induction of HSC aging. Here, using genetic models of both chronological and premature aging, we describe a multimodal role for p38α, the major p38MAPK isozyme in hematopoiesis, in HSC aging. We report that p38α regulates differentiation bias and sustains transplantation capacity of HSCs in the early phase of chronological aging. However, p38α decreased HSC transplantation capacity in the late progression phase of chronological aging. Furthermore, codeletion of p38α in mice deficient in ataxia-telangiectasia mutated, a model of premature aging, exacerbated aging-related HSC phenotypes seen in ataxia-telangiectasia mutated single-mutant mice. Overall, these studies provide new insight into multiple functions of p38MAPK, which both promotes and suppresses HSC aging context dependently.
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Envejecimiento/patología , Diferenciación Celular , Senescencia Celular , Células Madre Hematopoyéticas/metabolismo , Proteína Quinasa 14 Activada por Mitógenos/fisiología , Envejecimiento/metabolismo , Animales , Proteínas de la Ataxia Telangiectasia Mutada/fisiología , Proliferación Celular , Femenino , Hematopoyesis , Células Madre Hematopoyéticas/citología , Masculino , Ratones , Ratones Endogámicos C57BL , Ratones Noqueados , Fenotipo , Especies Reactivas de Oxígeno/metabolismoRESUMEN
Heart failure is a major public health problem, and abnormal iron metabolism is common in patients with heart failure. Although iron is necessary for metabolic homeostasis, it induces a programmed necrosis. Iron release from ferritin storage is through nuclear receptor coactivator 4 (NCOA4)-mediated autophagic degradation, known as ferritinophagy. However, the role of ferritinophagy in the stressed heart remains unclear. Deletion of Ncoa4 in mouse hearts reduced left ventricular chamber size and improved cardiac function along with the attenuation of the upregulation of ferritinophagy-mediated ferritin degradation 4 weeks after pressure overload. Free ferrous iron overload and increased lipid peroxidation were suppressed in NCOA4-deficient hearts. A potent inhibitor of lipid peroxidation, ferrostatin-1, significantly mitigated the development of pressure overload-induced dilated cardiomyopathy in wild-type mice. Thus, the activation of ferritinophagy results in the development of heart failure, whereas inhibition of this process protects the heart against hemodynamic stress.
Asunto(s)
Insuficiencia Cardíaca/etiología , Coactivadores de Receptor Nuclear/genética , Coactivadores de Receptor Nuclear/metabolismo , Animales , Aorta , Autofagia , Cardiomiopatías/tratamiento farmacológico , Constricción , Ciclohexilaminas/farmacología , Modelos Animales de Enfermedad , Ferritinas/genética , Ferritinas/metabolismo , Insuficiencia Cardíaca/tratamiento farmacológico , Hierro/metabolismo , Peroxidación de Lípido , Masculino , Ratones Endogámicos C57BL , Ratones Transgénicos , Miocitos Cardíacos/efectos de los fármacos , Miocitos Cardíacos/metabolismo , Fenilendiaminas/farmacologíaRESUMEN
Most seven transmembrane receptors (7TMRs) are G protein-coupled receptors; however, some 7TMRs evoke intracellular signals through ß-arrestin as a biased receptor. As several ß-arrestin-biased agonists have been reported to be cardioprotective, we examined the role of the chemokine receptor CXCR7 as a ß-arrestin-biased receptor in the heart. Among 510 7TMR genes examined, Cxcr7 was the most abundantly expressed in the murine heart. Single-cell RNA-sequencing analysis revealed that Cxcr7 was abundantly expressed in cardiomyocytes and fibroblasts. Cardiomyocyte-specific Cxcr7 null mice showed more prominent cardiac dilatation and dysfunction than control mice 4 weeks after myocardial infarction. In contrast, there was no difference in cardiac phenotypes between fibroblast-specific Cxcr7-knockout mice and control mice even after myocardial infarction. TC14012, a specific agonist of CXCR7, significantly recruited ß-arrestin to CXCR7 in CXCR7-expressing cells and activated extracellular signal-regulated kinase (ERK) in neonatal rat cardiomyocytes. Cxcr7 expression was significantly increased and ERK was activated in the border zone of the heart in control, but not Cxcr7 null mice. These results indicate that the abundantly expressed CXCR7 in cardiomyocytes may play a protective role in the heart as a ß-arrestin-biased receptor and that CXCR7 may be a novel therapeutic target for myocardial infarction.
Asunto(s)
Sistema de Señalización de MAP Quinasas , Infarto del Miocardio/metabolismo , Miocardio/metabolismo , Miocitos Cardíacos/metabolismo , Receptores CXCR/metabolismo , beta-Arrestina 1/metabolismo , Animales , Ratones , Ratones Noqueados , Infarto del Miocardio/genética , Infarto del Miocardio/patología , Miocardio/patología , Miocitos Cardíacos/patología , Oligopéptidos/farmacología , Receptores CXCR/agonistas , Receptores CXCR/genética , beta-Arrestina 1/genéticaRESUMEN
BACKGROUND: Proinflammatory cytokines play an important role in the pathogenesis of heart failure. The mechanisms responsible for maintaining sterile inflammation within failing hearts remain poorly defined. Although transcriptional control is important for proinflammatory cytokine gene expression, the stability of mRNA also contributes to the kinetics of immune responses. Regnase-1 is an RNase involved in the degradation of a set of proinflammatory cytokine mRNAs in immune cells. The role of Regnase-1 in nonimmune cells such as cardiomyocytes remains to be elucidated. METHODS: To examine the role of proinflammatory cytokine degradation by Regnase-1 in cardiomyocytes, cardiomyocyte-specific Regnase-1-deficient mice were generated. The mice were subjected to pressure overload by means of transverse aortic constriction to induce heart failure. Cardiac remodeling was assessed by echocardiography as well as histological and molecular analyses 4 weeks after operation. Inflammatory cell infiltration was examined by immunostaining. Interleukin-6 signaling was inhibited by administration with its receptor antibody. Overexpression of Regnase-1 in the heart was performed by adeno-associated viral vector-mediated gene transfer. RESULTS: Cardiomyocyte-specific Regnase-1-deficient mice showed no cardiac phenotypes under baseline conditions, but exhibited severe inflammation and dilated cardiomyopathy after 4 weeks of pressure overload compared with control littermates. Four weeks after transverse aortic constriction, the Il6 mRNA level was upregulated, but not other cytokine mRNAs, including tumor necrosis factor-α, in Regnase-1-deficient hearts. Although the Il6 mRNA level increased 1 week after operation in both Regnase-1-deficient and control hearts, it showed no increase in control hearts 4 weeks after operation. Administration of anti-interleukin-6 receptor antibody attenuated the development of inflammation and cardiomyopathy in cardiomyocyte-specific Regnase-1-deficient mice. In severe pressure overloaded wild-type mouse hearts, sustained induction of Il6 mRNA was observed, even though the protein level of Regnase-1 increased. Adeno-associated virus 9-mediated cardiomyocyte-targeted gene delivery of Regnase-1 or administration of anti-interleukin-6 receptor antibody attenuated the development of cardiomyopathy induced by severe pressure overload in wild-type mice. CONCLUSIONS: The degradation of cytokine mRNA by Regnase-1 in cardiomyocytes plays an important role in restraining sterile inflammation in failing hearts and the Regnase-1-mediated pathway might be a therapeutic target to treat patients with heart failure.
Asunto(s)
Inflamación/patología , Interleucina-6/metabolismo , Miocitos Cardíacos/metabolismo , ARN Mensajero/metabolismo , Ribonucleasas/genética , Animales , Anticuerpos/inmunología , Anticuerpos/uso terapéutico , Cardiomiopatía Dilatada/etiología , Cardiomiopatía Dilatada/metabolismo , Cardiomiopatía Dilatada/patología , Vectores Genéticos/metabolismo , Insuficiencia Cardíaca/etiología , Insuficiencia Cardíaca/prevención & control , Inflamación/prevención & control , Interleucina-6/genética , Ratones , Ratones Endogámicos C57BL , Ratones Noqueados , Receptores de Interleucina-6/inmunología , Ribonucleasas/deficiencia , Ribonucleasas/metabolismo , Regulación hacia ArribaRESUMEN
Mitochondrial deoxyribonucleic acid, containing the unmethylated cytidine-phosphate-guanosine motif, stimulates Toll-like receptor 9 to induce inflammation and heart failure. A small chemical, E6446 [(6-[3-(pyrrolidin-1-yl)propoxy)-2-(4-(3-(pyrrolidin-1-yl)propoxy)phenyl]benzo[d]oxazole)], is a specific Toll-like receptor 9 inhibitor in cardiomyocytes. In this study, we showed that E6446 exerts beneficial effects for the prevention and treatment of pressure overload-induced heart failure in mice. When administered before the operation and chronically thereafter, E6446 prevented the development of left ventricular dilatation as well as cardiac dysfunction, fibrosis, and inflammation. Furthermore, when administered after the manifestation of cardiac dysfunction, E6446 slowed progression of cardiac remodeling. Thus, the inhibitor may be a novel therapeutic agent for treating patients with heart failure.
RESUMEN
In myocardial ischemia/reperfusion injury, the innate immune and subsequent inflammatory responses play a crucial role in the extension of myocardial damage. Toll-like receptor 9 (TLR9) is a critical receptor for recognizing unmethylated CpG motifs that mitochondria contain in their DNA, and induces inflammatory responses. The aim of this study was to elucidate the role of TLR9 in myocardial ischemia/reperfusion injury. Isolated hearts from TLR9-deficient and control wild-type mice were subjected to 35 min of global ischemia, followed by 60â¯min of reperfusion with Langendorff apparatus. Furthermore, wild-type mouse hearts were infused with DNase I and subjected to ischemia/reperfusion. Ablation of TLR9-mediated signaling pathway attenuates myocardial ischemia/reperfusion injury and inflammatory responses, and digestion of extracellular mitochondrial DNA released from the infarct heart partially improved myocardial ischemia/reperfusion injury with no effect on inflammatory responses. TLR9 could be a therapeutic target to reduce myocardial ischemia/reperfusion injury.
Asunto(s)
Daño por Reperfusión Miocárdica/metabolismo , Daño por Reperfusión Miocárdica/patología , Receptor Toll-Like 9/metabolismo , Animales , Citocinas/metabolismo , Desoxirribonucleasa I/metabolismo , Regulación de la Expresión Génica , Pruebas de Función Cardíaca , Mediadores de Inflamación/metabolismo , Ratones Endogámicos C57BL , Daño por Reperfusión Miocárdica/genética , Daño por Reperfusión Miocárdica/fisiopatología , Necrosis , ARN Mensajero/genética , ARN Mensajero/metabolismoRESUMEN
The fibrogenic response in tissue-resident fibroblasts is determined by the balance between activation and repression signals from the tissue microenvironment. While the molecular pathways by which transforming growth factor-1 (TGF-ß1) activates pro-fibrogenic mechanisms have been extensively studied and are recognized critical during fibrosis development, the factors regulating TGF-ß1 signaling are poorly understood. Here we show that macrophage hypoxia signaling suppresses excessive fibrosis in a heart via oncostatin-m (OSM) secretion. During cardiac remodeling, Ly6Chi monocytes/macrophages accumulate in hypoxic areas through a hypoxia-inducible factor (HIF)-1α dependent manner and suppresses cardiac fibroblast activation. As an underlying molecular mechanism, we identify OSM, part of the interleukin 6 cytokine family, as a HIF-1α target gene, which directly inhibits the TGF-ß1 mediated activation of cardiac fibroblasts through extracellular signal-regulated kinase 1/2-dependent phosphorylation of the SMAD linker region. These results demonstrate that macrophage hypoxia signaling regulates fibroblast activation through OSM secretion in vivo.
Asunto(s)
Fibrosis/metabolismo , Hipoxia/metabolismo , Macrófagos/metabolismo , Oncostatina M/metabolismo , Animales , Antígenos Ly/genética , Antígenos Ly/metabolismo , Femenino , Fibroblastos/metabolismo , Fibrosis/genética , Fibrosis/patología , Hipoxia/genética , Hipoxia/patología , Subunidad alfa del Factor 1 Inducible por Hipoxia/genética , Subunidad alfa del Factor 1 Inducible por Hipoxia/metabolismo , Masculino , Ratones , Ratones Endogámicos C57BL , Proteína Quinasa 1 Activada por Mitógenos/genética , Proteína Quinasa 1 Activada por Mitógenos/metabolismo , Proteína Quinasa 3 Activada por Mitógenos/genética , Proteína Quinasa 3 Activada por Mitógenos/metabolismo , Oncostatina M/genética , Fosforilación , Transducción de Señal , Proteínas Smad/genética , Proteínas Smad/metabolismo , Factor de Crecimiento Transformador beta1/metabolismoRESUMEN
Neurogenesis in specific brain regions in adult mammals decreases with age. Progressive reduction in the proliferation of neural stem and progenitor cells (NS/PCs) is a primary cause of this age-associated decline. However, the mechanism responsible for this reduction is poorly understood. We identify p38 MAPK as a key factor in the proliferation of neural progenitor cells (NPCs) in adult neurogenic niches. p38 expression in adult NS/PCs is downregulated during aging. Deletion of p38α in NS/PCs specifically reduces the proliferation of NPCs but not stem cells. Conversely, forced expression of p38α in NS/PCs in the aged mouse subventricular zone (SVZ) restores NPC proliferation and neurogenesis, and prevents age-dependent SVZ atrophy. We also found that p38 is necessary for suppressing the expression of Wnt antagonists DKK1 and SFRP3, which inhibit the proliferation of NPCs. Age-related reduction in p38 thus leads to decreased adult neurogenesis via downregulation of Wnt signaling.