RESUMO
Transcriptional co-activator with PDZ-binding motif (TAZ) is a key mediator of the Hippo signaling pathway and regulates structural and functional homeostasis in various tissues. TAZ activation is associated with the development of pancreatic cancer in humans, but it is unclear whether TAZ directly affects the structure and function of the pancreas. So we sought to identify the TAZ function in the normal pancreas. TAZ defect caused structural changes in the pancreas, particularly islet cell shrinkage and decreased insulin production and ß-cell markers expression, leading to hyperglycemia. Interestingly, TAZ physically interacted with the pancreatic and duodenal homeobox 1 (PDX1), a key insulin transcription factor, through the N-terminal domain of TAZ and the homeodomain of PDX1. TAZ deficiency decreased the DNA-binding and transcriptional activity of PDX1, whereas TAZ overexpression promoted PDX1 activity and increased insulin production even in a low glucose environment. Indeed, high glucose increased insulin production by turning off the Hippo pathway and inducing TAZ activation in pancreatic ß-cells. Ectopic TAZ overexpression along with PDX1 activation was sufficient to produce insulin in non-ß-cells. TAZ deficiency impaired the mesenchymal stem cell differentiation into insulin-producing cells (IPCs), whereas TAZ recovery restored normal IPCs differentiation. Compared to WT control, body weight increased in TAZ-deficient mice with age and even more with a high-fat diet (HFD). TAZ deficiency significantly exacerbated HFD-induced glucose intolerance and insulin resistance. Therefore, TAZ deficiency impaired pancreatic insulin production, causing hyperglycemia and exacerbating HFD-induced insulin resistance, indicating that TAZ may have a beneficial effect in treating insulin deficiency in diabetes.
Assuntos
Proteínas Adaptadoras de Transdução de Sinal/metabolismo , Proteínas de Homeodomínio/metabolismo , Insulina/metabolismo , Transativadores/metabolismo , Proteínas Adaptadoras de Transdução de Sinal/deficiência , Proteínas Adaptadoras de Transdução de Sinal/genética , Animais , Diferenciação Celular , Linhagem Celular , Dieta Hiperlipídica , Glucose/farmacologia , Via de Sinalização Hippo/efeitos dos fármacos , Proteínas de Homeodomínio/genética , Humanos , Hiperglicemia/metabolismo , Hiperglicemia/patologia , Hiperglicemia/veterinária , Insulina/genética , Resistência à Insulina , Células Secretoras de Insulina/citologia , Células Secretoras de Insulina/efeitos dos fármacos , Células Secretoras de Insulina/metabolismo , Masculino , Células-Tronco Mesenquimais/citologia , Células-Tronco Mesenquimais/metabolismo , Camundongos , Camundongos Endogâmicos C57BL , Camundongos Knockout , Regiões Promotoras Genéticas , Transativadores/genética , Ativação TranscricionalRESUMO
Testosterone is a hormone essential for male reproductive function. It is produced primarily by Leydig cells in the testicle through activation of steroidogenic acute regulatory protein and a series of steroidogenic enzymes, including a cytochrome P450 side-chain cleavage enzyme (cytochome P450 family 11 subfamily A member 1), 17α-hydroxylase (cytochrome P450 family 17 subfamily A member 1), and 3ß-hydroxysteroid dehydrogenase. These steroidogenic enzymes are mainly regulated at the transcriptional level, and their expression is increased by the nuclear receptor 4A1. However, the effect on Leydig cell function of a small molecule-activating ligand, amodiaquine (AQ), is unknown. We found that AQ effectively and significantly increased testosterone production in TM3 and primary Leydig cells through enhanced expression of steroidogenic acute regulatory protein, cytochome P450 family 11 subfamily A member 1, cytochrome P450 family 17 subfamily A member 1, and 3ß-hydroxysteroid dehydrogenase. Concurrently, AQ dose-dependently increased the expression of 3-hydroxy-3-methylglutaryl-CoA reductase, a key enzyme in the cholesterol synthesis pathway, through induction of the transcriptional and DNA-binding activities of nuclear receptor 4A1, contributing to increased cholesterol synthesis in Leydig cells. Furthermore, AQ increased the expression of fatty acid synthase and diacylglycerol acyltransferase and potentiated de novo synthesis of fatty acids and triglycerides (TGs). Lipidomics profiling further confirmed a significant elevation of intracellular lipid and TG levels by AQ in Leydig cells. These results demonstrated that AQ effectively promotes testosterone production and de novo synthesis of cholesterol and TG in Leydig cells, indicating that AQ may be beneficial for treating patients with Leydig cell dysfunction and subsequent testosterone deficiency.
Assuntos
Amodiaquina/farmacologia , Colesterol/biossíntese , Células Intersticiais do Testículo/efeitos dos fármacos , Testosterona/biossíntese , Triglicerídeos/biossíntese , Animais , Células Intersticiais do Testículo/metabolismo , Masculino , Camundongos , Camundongos Endogâmicos C57BLRESUMO
Transcriptional coactivator with PDZ-binding motif (TAZ) plays crucial role in maintaining testicular structure and function via regulation of senescence of spermatogenic cells. However, it remains unclear whether TAZ is involved in testosterone biosynthesis in testicular Leydig cells. We found that TAZ deficiency caused aberrant Leydig cell expansion and increased lipid droplet formation, which was significantly associated with increased lipogenic enzyme expression. Additionally, the expression of key steroidogenic enzymes, including steroidogenic acute regulatory protein, cytochrome P450 (CYP) 11A1, CYP17A1, and 3ß-hydroxysteroid dehydrogenase, was greatly increased in TAZ-deficient testes and primary Leydig cells. Interestingly, the transcriptional activity of nuclear receptor 4 A1 (NR4A1) was dramatically suppressed by TAZ; however, the protein expression and the subcellular localization of NR4A1 were not affected by TAZ. TAZ directly associated with the N-terminal region of NR4A1 and substantially suppressed its DNA-binding and transcriptional activities. Stable expression of TAZ in the mouse Leydig TM3 cell line decreased the expression of key steroidogenic enzymes, whereas knockdown of endogenous TAZ in TM3 cells increased transcripts of steroidogenic genes induced by NR4A1. Consistently, testosterone production was enhanced within TAZ-deficient Leydig cells. However, TAZ deficiency resulted in decreased testosterone secretion caused by dysfunctional mitochondria and lysosomes. Therefore, TAZ plays essential role in NR4A1-induced steroidogenic enzyme expression and testosterone production in Leydig cells.
Assuntos
17-Hidroxiesteroide Desidrogenases/antagonistas & inibidores , Células Intersticiais do Testículo/metabolismo , Membro 1 do Grupo A da Subfamília 4 de Receptores Nucleares/metabolismo , Fosfoproteínas/antagonistas & inibidores , Esteroide 17-alfa-Hidroxilase/antagonistas & inibidores , Testosterona/metabolismo , Transativadores/fisiologia , 17-Hidroxiesteroide Desidrogenases/genética , 17-Hidroxiesteroide Desidrogenases/metabolismo , Proteínas Adaptadoras de Transdução de Sinal , Animais , Masculino , Camundongos , Camundongos Endogâmicos C57BL , Camundongos Knockout , Membro 1 do Grupo A da Subfamília 4 de Receptores Nucleares/genética , Fosfoproteínas/genética , Fosfoproteínas/metabolismo , Esteroide 17-alfa-Hidroxilase/genética , Esteroide 17-alfa-Hidroxilase/metabolismoRESUMO
In response to liver injury, the liver undergoes a regeneration process to retain its mass and function. However, the regeneration mechanism has not been fully clarified. This study investigated the role of transcriptional coactivator with PDZ-binding motif (TAZ), a Hippo-signaling effector, in liver regeneration. We observed that TAZ stimulates liver regeneration after liver injury. After partial hepatectomy (PHx) or carbon tetrachloride damage, TAZ was required for liver regeneration to increase hepatic cell proliferation and resist hepatic apoptosis, which were decreased in liver-specific TAZ knockout (LKO) mice. TAZ stimulated macrophage infiltration, resulting in IL-6 production, which induced liver regeneration. In LKO mice, IL-6-induced activation of signal transducer and activator of transcription 3, ERK, and PKB was decreased. We also observed that periductal fibrogenesis was significantly increased in LKO mice during liver regeneration after PHx, which was caused by increased hepatic apoptosis. Our results suggest that TAZ stimulates liver regeneration through IL-6-induced hepatocyte proliferation and inhibition of cell death after liver injury.-Kim, A. R., Park, J. I., Oh, H. T., Kim, K. M., Hwang, J.-H., Jeong, M. G., Kim, E.-H., Hwang, E. S., Hong, J.-H. TAZ stimulates liver regeneration through interleukin-6-induced hepatocyte proliferation and inhibition of cell death after liver injury.
Assuntos
Interleucina-6/metabolismo , Regeneração Hepática , Fígado/lesões , Transativadores/metabolismo , Proteínas Adaptadoras de Transdução de Sinal , Alelos , Animais , Apoptose , Tetracloreto de Carbono , Morte Celular , Proliferação de Células , MAP Quinases Reguladas por Sinal Extracelular/metabolismo , Hepatectomia , Hepatócitos/citologia , Hepatócitos/metabolismo , Fígado/metabolismo , Masculino , Camundongos , Camundongos Endogâmicos C57BL , Camundongos Knockout , Proteínas Proto-Oncogênicas c-akt/metabolismo , Fator de Transcrição STAT3/metabolismoRESUMO
Muscle loss is a typical process of aging. Green tea consumption is known to slow down the progress of aging. Their underlying mechanisms, however, remain largely unknown. In this study, we investigated the effect of (-)-epigallocatechin-3-gallate (EGCG), a polyphenolic compound of green tea, on myogenic differentiation and found that EGCG significantly increases myogenic differentiation. After EGCG treatment, the expression of myogenic marker genes, such as myosin heavy chain, are increased through activation of TAZ, a transcriptional coactivator with a PDZ-binding motif. TAZ-knockdown does not stimulate EGCG-induced myogenic differentiation. EGCG facilitates the interaction between TAZ and MyoD, which stimulates MyoD-mediated gene transcription. EGCG induces nuclear localization of TAZ through the dephosphorylation of TAZ at its Ser89 residue, which relieves 14-3-3 binding in the cytosol. Interestingly, inactivation of Lats kinase is observed after EGCG treatment, which is responsible for the production of dephosphorylated TAZ. Together, these results suggest that EGCG induces myogenic differentiation through TAZ, suggesting that TAZ plays an important role in EGCG induced muscle regeneration.
Assuntos
Catequina/análogos & derivados , Diferenciação Celular/efeitos dos fármacos , Mioblastos/efeitos dos fármacos , Células Satélites de Músculo Esquelético/efeitos dos fármacos , Fatores de Transcrição/agonistas , Proteínas 14-3-3/genética , Proteínas 14-3-3/metabolismo , Aciltransferases , Animais , Catequina/farmacologia , Linhagem Celular , Regulação da Expressão Gênica , Células HEK293 , Humanos , Camundongos , Camundongos Endogâmicos C57BL , Proteína MyoD/genética , Proteína MyoD/metabolismo , Mioblastos/citologia , Mioblastos/metabolismo , Miogenina/genética , Miogenina/metabolismo , Cadeias Pesadas de Miosina/genética , Cadeias Pesadas de Miosina/metabolismo , Cultura Primária de Células , Proteínas Serina-Treonina Quinases/antagonistas & inibidores , Proteínas Serina-Treonina Quinases/genética , Proteínas Serina-Treonina Quinases/metabolismo , Células Satélites de Músculo Esquelético/citologia , Células Satélites de Músculo Esquelético/metabolismo , Transdução de Sinais , Chá/química , Fatores de Transcrição/genética , Fatores de Transcrição/metabolismoRESUMO
Muscle weakness is one of the most common symptoms in aged individuals and increases risk of mortality. Thus, maintenance of muscle mass is important for inhibiting aging. In this study, we investigated the effect of catechins, polyphenol compounds in green tea, on muscle regeneration. We found that (-)-epicatechin gallate (ECG) and (-)-epigallocatechin-3-gallate (EGCG) activate satellite cells by induction of Myf5 transcription factors. For satellite cell activation, Akt kinase was significantly induced after ECG treatment and ECG-induced satellite cell activation was blocked in the presence of Akt inhibitor. ECG also promotes myogenic differentiation through the induction of myogenic markers, including Myogenin and Muscle creatine kinase (MCK), in satellite and C2C12 myoblast cells. Finally, EGCG administration to mice significantly increased muscle fiber size for regeneration. Taken together, the results suggest that catechins stimulate muscle stem cell activation and differentiation for muscle regeneration.
Assuntos
Catequina/farmacologia , Músculos/efeitos dos fármacos , Músculos/fisiologia , Fator Regulador Miogênico 5/biossíntese , Regeneração/efeitos dos fármacos , Células Satélites de Músculo Esquelético/citologia , Células Satélites de Músculo Esquelético/efeitos dos fármacos , Animais , Catequina/química , Diferenciação Celular/efeitos dos fármacos , Células Cultivadas , Relação Dose-Resposta a Droga , Masculino , Camundongos , Camundongos Endogâmicos C57BL , Conformação Molecular , Músculos/citologia , Fator Regulador Miogênico 5/metabolismo , Relação Estrutura-AtividadeRESUMO
Chloroquine (CQ) and amodiaquine (AQ) have been used for treating or preventing malaria for decades, and their application has expanded into treating inflammatory disease in humans. CQ and AQ are applicable for controlling rheumatoid arthritis, but their molecular mechanisms of anti-inflammatory activity remain to be elucidated. In this study, we examined the effects of CQ and AQ on T cell activation and T cell-mediated immune response. CQ had no significant effect on T cell numbers, but decreased the population of T cells with a high division rate. However, AQ treatment significantly increased the number of cells with low division rates and eliminated cells with high division rates, resulting in the inhibition of T cell proliferation triggered by T cell receptor stimulation, of which inhibition occurred in developing effector T helper and regulatory T cells, regardless of the different exogenous cytokines. Interestingly, the cyclin-dependent kinase inhibitor p21 was significantly and dose-dependently increased by CQ, and more potently by AQ, while other cell cycle regulators were unchanged. Both CQ and AQ elevated the transcription level of p21 though the activation of p53, but also blocked p21 protein degradation in the presence of cycloheximide, causing p21 protein accumulation mainly in the nucleus. Sustained treatment of developing T cells with either CQ or AQ suppressed IFN-γ production in a dose dependent manner and potently inhibited the differentiation of IFN-γ-producing Th1 cells. These results demonstrate that CQ and AQ increase the expression level of p21 and inhibit T cell proliferation and the development of IFN-γ-producing Th1 cells, thereby revealing beneficial roles in treating a wide range of chronic inflammatory diseases mediated by inflammatory T cells.
Assuntos
Amodiaquina/administração & dosagem , Cloroquina/administração & dosagem , Inibidor de Quinase Dependente de Ciclina p21/metabolismo , Linfócitos T/fisiologia , Células Th1/citologia , Células Th1/metabolismo , Animais , Anti-Inflamatórios/administração & dosagem , Diferenciação Celular/efeitos dos fármacos , Células Cultivadas , Relação Dose-Resposta a Droga , Mediadores da Inflamação/metabolismo , Camundongos , Camundongos Endogâmicos C57BL , Linfócitos T/efeitos dos fármacos , Células Th1/efeitos dos fármacos , Resultado do TratamentoRESUMO
Osteoporosis is a degenerative bone disease characterized by low bone mass and is caused by an imbalance between osteoblastic bone formation and osteoclastic bone resorption. It is known that the bioactive compounds present in green tea increase osteogenic activity and decrease the risk of fracture by improving bone mineral density. However, the detailed mechanism underlying these beneficial effects has yet to be elucidated. In this study, we investigated the osteogenic effect of (-)-epicatechin gallate (ECG), a major bioactive compound found in green tea. We found that ECG effectively stimulates osteoblast differentiation, indicated by the increased expression of osteoblastic marker genes. Up-regulation of osteoblast marker genes is mediated by increased expression and interaction of the transcriptional coactivator with PDZ-binding motif (TAZ) and Runt-related transcription factor 2 (RUNX2). ECG facilitates nuclear localization of TAZ through PP1A. PP1A is essential for osteoblast differentiation because inhibition of PP1A activity was shown to suppress ECG-mediated osteogenic differentiation. Taken together, the results showed that ECG stimulates osteoblast differentiation through the activation of TAZ and RUNX2, revealing a novel mechanism for green tea-stimulated osteoblast differentiation.
Assuntos
Antineoplásicos Fitogênicos/farmacologia , Catequina/análogos & derivados , Diferenciação Celular/efeitos dos fármacos , Núcleo Celular/metabolismo , Subunidade alfa 1 de Fator de Ligação ao Core/metabolismo , Osteoblastos/metabolismo , Fatores de Transcrição/biossíntese , Ativação Transcricional/efeitos dos fármacos , Transporte Ativo do Núcleo Celular/efeitos dos fármacos , Transporte Ativo do Núcleo Celular/fisiologia , Aciltransferases , Animais , Catequina/farmacologia , Diferenciação Celular/fisiologia , Linhagem Celular , Núcleo Celular/genética , Subunidade alfa 1 de Fator de Ligação ao Core/genética , Humanos , Camundongos , Osteoblastos/citologia , Proteína Fosfatase 2/genética , Proteína Fosfatase 2/metabolismo , Fatores de Transcrição/genética , Ativação Transcricional/fisiologiaRESUMO
Antofine (ANTF) is a phenanthroindolizidine alkaloid isolated from the root of Cynanchum paniculatum Kitagawa (Asclepiadaceae), which is used as an herbal remedy for pain and inflammation. ANTF also possesses antiviral and antitumorigenic activities. In this study, we investigated the role of ANTF in adipogenesis. Chronic ABTF administration suppressed adipocyte differentiation and marker expression in a dose-dependent manner. Furthermore, acute administration of ANTF at early stages of differentiation process inhibited lipid droplet formation and adipogenic gene expression. ANTF Treatment decreased expression of PPARγ protein, a master transcription factor in the regulation of adipocyte differentiation, leading to a suppression of aP2 promoter activity. These results suggest that ANTF exerts potent anti-adipogenic effects via direct suppression of PPARγ protein expression, with consequent downregulation of adipogenic gene expression.
Assuntos
Adipogenia/efeitos dos fármacos , Produtos Biológicos/farmacologia , Indóis/farmacologia , PPAR gama/biossíntese , Fenantrolinas/farmacologia , Células 3T3-L1 , Adipócitos/efeitos dos fármacos , Adipogenia/genética , Animais , Apocynaceae/química , Produtos Biológicos/química , Produtos Biológicos/isolamento & purificação , Diferenciação Celular/efeitos dos fármacos , Relação Dose-Resposta a Droga , Regulação para Baixo/efeitos dos fármacos , Indóis/química , Indóis/isolamento & purificação , Gotículas Lipídicas/efeitos dos fármacos , Gotículas Lipídicas/metabolismo , Camundongos , PPAR gama/genética , PPAR gama/metabolismo , Fenantrolinas/química , Fenantrolinas/isolamento & purificação , Raízes de Plantas/química , Relação Estrutura-AtividadeRESUMO
Rhizomes of Curcuma phaeocaulis Valeton (Zingiberaceae) have traditionally been used for controlling inflammatory conditions. Numerous studies have aimed to isolate and characterize the bioactive constituents of C. phaeocaulis. It has been reported that its anti-inflammatory properties are a result of cyclooxygenase-2 inhibition; however, its effect on the T-cell function remains to be elucidated. In this study, four known sesquiterpenoids, viz., ar-turmerone (TM), germacrone (GM), (+)-(4S,5S)-germacrone-4,5-epoxide (GE), and curzerenone (CZ), were isolated from C. phaeocaulis rhizomes and evaluated for their effects on the CD4(+) T-cell function. While GM, GE, and CZ had no effect on the activation of splenic T cells or CD4(+) T cells, TM suppressed the interferon (IFN)-γ production, without affecting the interleukin (IL)-4 expression. TM also decreased the expression of IL-2 in CD4(+) T cells, but did not change their cell-division rates upon stimulation. These results suggest that TM, a major constituent of C. phaeocaulis rhizomes selectively exerts potent anti-inflammatory effects via suppression of the inflammatory cytokines IFN-γ and IL-2.
Assuntos
Anti-Inflamatórios/farmacologia , Curcuma/química , Citocinas/imunologia , Cetonas/farmacologia , Sesquiterpenos/farmacologia , Linfócitos T/efeitos dos fármacos , Animais , Anti-Inflamatórios/isolamento & purificação , Linfócitos T CD4-Positivos/efeitos dos fármacos , Linfócitos T CD4-Positivos/imunologia , Células Cultivadas , Citocinas/antagonistas & inibidores , Interferon gama/antagonistas & inibidores , Interferon gama/imunologia , Interleucina-2/antagonistas & inibidores , Interleucina-2/imunologia , Cetonas/isolamento & purificação , Camundongos Endogâmicos BALB C , Sesquiterpenos/isolamento & purificação , Baço/citologia , Linfócitos T/imunologiaRESUMO
Transcriptional coactivator with a PDZ-binding motif (TAZ) plays a key role in normal tissue homeostasis and tumorigenesis through interaction with several transcription factors. In particular, TAZ deficiency causes abnormal alveolarization and emphysema, and persistent TAZ overexpression contributes to lung cancer and pulmonary fibrosis, suggesting the possibility of a complex mechanism of TAZ function. Recent studies suggest that nuclear factor erythroid 2-related factor 2 (NRF2), an antioxidant defense system, induces TAZ expression during tumorigenesis and that TAZ also activates the NRF2-mediated antioxidant pathway. We thus thought to elucidate the cross-regulation of TAZ and NRF2 and the underlying molecular mechanisms and functions. TAZ directly interacted with NRF2 through the N-terminal domain and suppressed the transcriptional activity of NRF2 by preventing NRF2 from binding to DNA. In addition, the return of NRF2 to basal levels after signaling was inhibited in TAZ deficiency, resulting in sustained nuclear NRF2 levels and aberrantly increased expression of NRF2 targets. TAZ deficiency failed to modulate optimal NRF2 signaling and concomitantly impaired lysosomal acidification and lysosomal enzyme function, accumulating the abnormal autophagy vesicles and reactive oxygen species and causing protein oxidation and cellular damage in the lungs. TAZ restoration to TAZ deficiency normalized dysregulated NRF2 signaling and aberrant lysosomal function and triggered the normal autophagy-lysosomal pathway. Therefore, TAZ is indispensable for the optimal regulation of NRF2-mediated autophagy-lysosomal pathways and for preventing pulmonary damage caused by oxidative stress and oxidized proteins.
Assuntos
Autofagia , Lisossomos , Fator 2 Relacionado a NF-E2 , Fator 2 Relacionado a NF-E2/metabolismo , Autofagia/fisiologia , Lisossomos/metabolismo , Animais , Camundongos , Humanos , Proteínas com Motivo de Ligação a PDZ com Coativador Transcricional/metabolismo , Transdução de Sinais , Fatores de Transcrição/metabolismo , Fatores de Transcrição/genética , Espécies Reativas de Oxigênio/metabolismo , Proteínas Adaptadoras de Transdução de SinalRESUMO
Background: Pulmonary fibrosis (PF) is a progressive lung disease characterized by fibroblast accumulation and collagen deposition, resulting in lung scarring and impaired gas exchange. Current treatments for idiopathic pulmonary fibrosis (IPF) have limited efficacy and significant side effects. Heat shock protein 27 (HSP27) has emerged as a potential therapeutic target for PF due to its involvement in fibrotic processes. However, effective HSP27 inhibitors for PF treatment are still lacking. Methods: To assess the anti-fibrotic effects of NA49, we utilized murine PF models induced by radiation (IR) or bleomycin (BLM). We administered NA49 to the PF mice and evaluated its impact on lung fibrosis progression. We also investigated the molecular mechanisms underlying NA49's effects, focusing on its inhibition of EMT-related signaling pathways. Results: In our study, we evaluated the potential of a novel HSP27 inhibitor, NA49, in preclinical models of PF. NA49 effectively suppressed PF development in radiation and bleomycin-induced PF models. It reduced fibrosis, inhibited NFkB signaling, and downregulated EMT-related molecules. Importantly, we evaluated the safety profile of NA49 by assessing its impact on DNA strand breakage. Compared to previous HSP27 inhibitors, NA49 showed lower levels of DNA damage in human lung epithelial cells, and suggests that NA49 may have reduced toxicity compared to other HSP27 inhibitors. Overall, our results demonstrate that NA49 effectively inhibits PF development in preclinical models. It reduces lung fibrosis, inhibits EMT-related signaling pathways, and exhibits improved safety profiles. These findings highlight the potential of NA49 as a promising candidate for the treatment of PF. Conclusion: NA49 exhibited significant anti-fibrotic effects, inhibiting fibrosis development and EMT-related signaling pathways. Moreover, NA49 showed improved safety profiles compared to previous HSP27 inhibitors.
RESUMO
BACKGROUND: Exercise stimulates the activation of muscle satellite cells, which facilitate the maintenance of stem cells and their myogenic conversion during muscle regeneration. However, the underlying mechanism is not yet fully understood. This study shows that the transcriptional co-activator with PDZ-binding motif (TAZ) stimulates muscle regeneration via satellite cell activation. METHODS: Tazf/f mice were crossed with the paired box gene 7 (Pax7)creERT2 mice to generate muscle satellite cell-specific TAZ knockout (sKO) mice. Mice were trained in an endurance exercise programme for 4 weeks. Regenerated muscles were harvested and analysed by haematoxylin and eosin staining. Muscle tissues were also analysed by immunofluorescence staining, immunoblot analysis and quantitative reverse transcription PCR (qRT-PCR). For the in vitro study, muscle satellite cells from wild-type and sKO mice were isolated and analysed. Mitochondrial DNA was quantified by qRT-PCR using primers that amplify the cyclooxygenase-2 region of mitochondrial DNA. Quiescent and activated satellite cells were stained with MitoTracker Red CMXRos to analyse mitochondria. To study the p38 mitogen-activated protein kinase (MAPK)-TAZ signalling axis, p38 MAPK was activated by introducing the MAPK kinase 6 plasmid into satellite cells and also inhibited by treatment with the p38 MAPK inhibitor, SB203580. RESULTS: TAZ interacts with Pax7 to induce Myf5 expression and stimulates mammalian target of rapamycin signalling for satellite cell activation. In sKO mice, TAZ depletion reduces muscle satellite cell number by 38% (0.29 ± 0.073 vs. 0.18 ± 0.034, P = 0.0082) and muscle regeneration. After muscle injury, TAZ levels (2.59-fold, P < 0.0001) increase in committed cells compared to self-renewing cells during asymmetric satellite cell division. Mechanistically, the polarity protein Pard3 induces TAZ (2.01-fold, P = 0.008) through p38 MAPK, demonstrating that the p38 MAPK-TAZ axis is important for muscle regeneration. Physiologically, endurance exercise training induces muscle satellite cell activation and increases muscle fibre diameter (1.33-fold, 43.21 ± 23.59 vs. 57.68 ± 23.26 µm, P = 0.0004) with increased TAZ levels (1.76-fold, P = 0.017). However, sKO mice had a 39% reduction in muscle satellite cell number (0.20 ± 0.03 vs. 0.12 ± 0.02, P = 0.0013) and 24% reduction in muscle fibre diameter compared to wild-type mice (61.07 ± 23.33 vs. 46.60 ± 24.29 µm, P = 0.0006). CONCLUSIONS: Our results demonstrate a novel mechanism of TAZ-induced satellite cell activation after muscle injury and exercise, suggesting that activation of TAZ in satellite cells may ameliorate the muscle ageing phenotype and may be an important target protein for the drug development in sarcopenia.
Assuntos
Células Satélites de Músculo Esquelético , Proteínas Quinases p38 Ativadas por Mitógeno , Animais , Camundongos , DNA Mitocondrial/metabolismo , Mamíferos/metabolismo , Fibras Musculares Esqueléticas/metabolismo , Proteínas Quinases p38 Ativadas por Mitógeno/metabolismo , Células Satélites de Músculo Esquelético/metabolismo , Transdução de Sinais , Proteína Quinase 14 Ativada por MitógenoRESUMO
Background: Endothelial dysfunction is a systemic disorder and is involved in the pathogenesis of several human diseases. Hemodynamic shear stress plays an important role in vascular homeostasis including nitric oxide (NO) production. Impairment of NO production in endothelial cells stimulates the capillarization of liver sinusoidal endothelial cells, followed by hepatic stellate cell activation, inducing liver fibrosis. However, the detailed mechanism underlying NO production is not well understood. In hepatocytes, transcriptional co-activator with PDZ-binding motif (TAZ) has been reported to be involved in liver fibrosis. However, the role of endothelial TAZ in liver fibrosis has not been investigated. In this study, we uncovered the role TAZ in endothelial cell NO production, and its subsequent effects on liver fibrosis. Methods: TAZ-floxed mice were crossed with Tie2-cre transgenic mice, to generate endothelium-specific TAZ-knockout (eKO) mice. To induce liver damage, a 3,5-diethoxycarboncyl-1,4-dihydrocollidine, methionine-choline-deficient diet, or partial hepatectomy was applied. Liver fibrosis and endothelial dysfunction were analyzed in wild-type and eKO mice after liver damage. In addition, liver sinusoidal endothelial cell (LSEC) was used for in vitro assays of protein and mRNA levels. To study transcriptional regulation, chromatin immunoprecipitation and luciferase reporter assays were performed. Results: In liver of eKO mice, LSEC capillarization was observed, evidenced by loss of fenestrae and decreased LSEC-specific marker gene expression. LSEC capillarization of eKO mouse is caused by downregulation of endothelial nitric oxide synthase expression and subsequent decrease in NO concentration, which is transcriptionally regulated by TAZ-KLF2 binding to Nos3 promoter. Diminished NO concentration by TAZ knockout in endothelium accelerates liver fibrosis induced by liver damages. Conclusions: Endothelial TAZ inhibits damage-induced liver fibrosis via NO production. This highlights an unappreciated role of TAZ in vascular health and liver diseases.
Assuntos
Hepatopatias , Óxido Nítrico , Camundongos , Humanos , Animais , Óxido Nítrico/metabolismo , Células Endoteliais/metabolismo , Cirrose Hepática/metabolismo , Hepatopatias/patologia , Fígado/metabolismo , Endotélio/metabolismoRESUMO
Psoriasis is a chronic skin inflammation caused by a dysfunctional immune system, which causes systemic inflammation in various organs and tissues. Due to the risk of systemic inflammation and recurrence of psoriasis, it is important to identify the critical targets in the pathogenesis of psoriasis and develop targeted therapeutics. Dimerized translationally controlled tumor protein (dTCTP) promotes immune cell activation as a pro-inflammatory cytokine and plays a role in developing allergic diseases such as asthma and rhinitis. Here, we sought to explore whether dTCTP and its inhibition contributed to the development and control of imiquimod (IMQ)-induced psoriasis. Topical application of IMQ inflamed the skin of the back and ear, increased inflammatory cytokines, and decreased regulatory T cell markers. Interestingly, TCTP was significantly increased in inflamed skin and immune cells such as T cells, B cells, and macrophages after IMQ treatment and was secreted into the serum to undergo dimerization. Extracellular dTCTP treatment selectively suppressed regulatory T (Treg) cells, not other effector T helper (Th) cells, and increased M1 macrophages. Moreover, dTCTP-binding peptide 2 (dTBP2), a dTCTP inhibitor peptide, effectively attenuated the systemic inflammatory responses, including Th17 cell response, and alleviated psoriatic skin inflammation. dTBP2 blocked dTCTP-mediated Treg suppression and stimulated the expression of Treg cell markers in the spleen and inflammatory skin lesions. These results suggest that dTCTP dysregulated immune balance through Treg suppression in psoriatic inflammation and that functional inhibition of dTCTP by dTBP2 maintained immune homeostasis and attenuated inflammatory skin diseases by expanding Treg cells.
Assuntos
Psoríase , Linfócitos T Reguladores , Animais , Citocinas/metabolismo , Modelos Animais de Doenças , Imiquimode/farmacologia , Inflamação/metabolismo , Camundongos , Camundongos Endogâmicos BALB C , Peptídeos/farmacologia , Psoríase/induzido quimicamente , Psoríase/tratamento farmacológico , Pele , Linfócitos T Reguladores/metabolismo , Células Th17 , Proteína Tumoral 1 Controlada por TraduçãoRESUMO
Mitochondria are energy-generating organelles and mitochondrial biogenesis is stimulated to meet energy requirements in response to extracellular stimuli, including exercise. However, the mechanisms underlying mitochondrial biogenesis remain unknown. Here, we demonstrate that transcriptional coactivator with PDZ-binding motif (TAZ) stimulates mitochondrial biogenesis in skeletal muscle. In muscle-specific TAZ-knockout (mKO) mice, mitochondrial biogenesis, respiratory metabolism, and exercise ability were decreased compared to wild-type mice. Mechanistically, TAZ stimulates the translation of mitochondrial transcription factor A via Ras homolog enriched in brain (Rheb)/Rheb like 1 (Rhebl1)-mTOR axis. TAZ stimulates Rhebl1 expression via TEA domain family transcription factor. Rhebl1 introduction by adeno-associated virus or mTOR activation recovered mitochondrial biogenesis in mKO muscle. Physiologically, mKO mice did not stimulate exercise-induced mitochondrial biogenesis. Collectively, our results suggested that TAZ is a novel stimulator for mitochondrial biogenesis and exercise-induced muscle adaptation.
Assuntos
Proteínas Adaptadoras de Transdução de Sinal/genética , Proteínas de Ligação a DNA/genética , Mitocôndrias Musculares/genética , Proteínas Mitocondriais/genética , Biogênese de Organelas , Condicionamento Físico Animal , Fatores de Transcrição/genética , Proteínas Adaptadoras de Transdução de Sinal/metabolismo , Trifosfato de Adenosina/metabolismo , Animais , Linhagem Celular , Células Cultivadas , DNA Mitocondrial/genética , DNA Mitocondrial/metabolismo , Proteínas de Ligação a DNA/metabolismo , Embrião de Mamíferos/citologia , Embrião de Mamíferos/metabolismo , Fibroblastos/citologia , Fibroblastos/metabolismo , Células HEK293 , Humanos , Camundongos Knockout , Mitocôndrias Musculares/metabolismo , Proteínas Mitocondriais/metabolismo , Músculo Esquelético/citologia , Músculo Esquelético/metabolismo , Mioblastos/citologia , Mioblastos/metabolismo , Espécies Reativas de Oxigênio/metabolismo , Fatores de Transcrição/metabolismoRESUMO
CD4+ T helper (Th) cells play a crucial role in the modulation of innate and adaptive immune responses through the differentiation of Th precursor cells into several subsets, including Th1, Th2, Th17, and regulatory T (Treg) cells. Effector Th and Treg cells are distinguished by the production of signature cytokines and are important for eliminating intracellular and extracellular pathogens and maintaining immune homeostasis. Stimulation of naïve Th cells by T cell receptor and specific cytokines activates master transcription factors and induces lineage specification during the differentiation of Th cells. The master transcription factors directly activate the transcription of signature cytokine genes and also undergo post-translational modifications to fine-tune cytokine production and maintain immune balance through cross-regulation with each other. This review highlights the post-translational modifications of master transcription factors that control the differentiation of effector Th and Treg cells and provides additional insights on the immune regulation mediated by protein arginine-modifying enzymes in effector Th cells.
Assuntos
Processamento de Proteína Pós-Traducional/imunologia , Linfócitos T Auxiliares-Indutores/imunologia , Fatores de Transcrição/imunologia , Diferenciação Celular , HumanosRESUMO
Transcriptional coactivator with PDZ-binding motif (TAZ) has been extensively characterized in organ development, tissue regeneration, and tumor progression. In particular, TAZ functions as a Hippo mediator that regulates organ size, tumor growth and migration. It is highly expressed in various types of human cancer, and has been reported to be associated with tumor metastasis and poor outcomes in cancer patients, suggesting that TAZ is an oncogenic regulator. Yes-associated protein (YAP) has 60% similarity in amino acid sequence to TAZ and plays redundant roles with TAZ in the regulation of cell proliferation and migration of cancer cells. Therefore, TAZ and YAP, which are encoded by paralogous genes, are referred to as TAZ/YAP and are suggested to be functionally equivalent. Despite its similarity to YAP, TAZ can be clearly distinguished from YAP based on its genetic, structural, and functional aspects. In addition, targeting superabundant TAZ can be a promising therapeutic strategy for cancer treatment; however, persistent TAZ inactivation may cause failure of tissue homeostatic control. This review focuses primarily on TAZ, not YAP, discusses its structural features and physiological functions in the regulation of tissue homeostasis, and provides new insights into the drug development targeting TAZ to control reproductive and musculoskeletal disorders.
Assuntos
Homeostase , Fatores de Transcrição/metabolismo , Proteínas Adaptadoras de Transdução de Sinal/química , Proteínas Adaptadoras de Transdução de Sinal/metabolismo , Humanos , Fatores de Transcrição/química , Proteínas de Sinalização YAPRESUMO
Heat shock protein beta-1 (HSPB1) is a multifaceted protein that controls cellular stress, modulates cell differentiation and development, and inhibits apoptosis of cancer cells. Increased HSPB1 expression is highly associated with poor outcomes in lung cancer by enhancing cell migration and invasion; therefore, targeting HSPB1 may be a promising therapeutic for lung cancer and fibrosis. Although the HSPB1 inhibitor J2 has been reported to exhibit potent antifibrotic effects, it remains unclear whether and how J2 directly modulates inflammatory immune responses in pulmonary fibrosis. In this study, we found that J2 potently attenuated irradiation or bleomycin-induced pulmonary fibrosis by significantly inhibiting the infiltration and activation of T cells and macrophages. J2 inhibited T-cell proliferation and subsequently suppressed T helper cell development. Although there was no significant effect of J2 on cell proliferation of M1 and M2 macrophages, J2 specifically increased the expression of Ym1 in M2 macrophages without affecting the expression of other M2 markers. Interestingly, J2 increased lysosomal degradation of HSPB1 and inhibited HSPB1-induced repression of signal transducer and activator of transcription 6 (STAT6), which simultaneously increased STAT6 and Ym1 expression. Ym1 production and secretion by J2-treated M2 macrophages substantially decreased IL-8 production by airway epithelial cells in vitro and in vivo, resulting in attenuation of airway inflammation. Taken together, we suggest that J2 has potential as a therapeutic agent for pulmonary fibrosis with increased HSPB1 expression through direct immune suppression by Ym1 production by M2 macrophages as well as T-cell suppression.
Assuntos
Anti-Inflamatórios/farmacologia , Antifibróticos/farmacologia , Proteínas de Choque Térmico/antagonistas & inibidores , Lectinas/metabolismo , Pulmão/efeitos dos fármacos , Chaperonas Moleculares/antagonistas & inibidores , Comunicação Parácrina , Pneumonia/prevenção & controle , Fibrose Pulmonar/prevenção & controle , beta-N-Acetil-Hexosaminidases/metabolismo , Animais , Bleomicina , Linfócitos T CD4-Positivos/efeitos dos fármacos , Linfócitos T CD4-Positivos/imunologia , Linfócitos T CD4-Positivos/metabolismo , Linfócitos T CD8-Positivos/efeitos dos fármacos , Linfócitos T CD8-Positivos/imunologia , Linfócitos T CD8-Positivos/metabolismo , Diferenciação Celular/efeitos dos fármacos , Proliferação de Células/efeitos dos fármacos , Citocinas/genética , Citocinas/metabolismo , Modelos Animais de Doenças , Células HEK293 , Proteínas de Choque Térmico/genética , Proteínas de Choque Térmico/metabolismo , Humanos , Pulmão/imunologia , Pulmão/metabolismo , Ativação Linfocitária/efeitos dos fármacos , Macrófagos/efeitos dos fármacos , Macrófagos/imunologia , Macrófagos/metabolismo , Masculino , Camundongos , Camundongos Endogâmicos C57BL , Camundongos Transgênicos , Chaperonas Moleculares/genética , Chaperonas Moleculares/metabolismo , Pneumonia/etiologia , Pneumonia/imunologia , Pneumonia/metabolismo , Fibrose Pulmonar/etiologia , Fibrose Pulmonar/imunologia , Fibrose Pulmonar/metabolismo , Células RAW 264.7 , Doses de Radiação , Transdução de SinaisRESUMO
Dimeric translationally controlled tumor protein (dTCTP), also known as histamine-releasing factor, amplifies allergic responses and its production has been shown to increase in inflammatory diseases such as allergic asthma. Despite the critical role of dTCTP in allergic inflammation, little is known about its production pathways, associated cellular networks, and underlying molecular mechanisms. In this study, we explored the dTCTP-mediated inflammatory networks and molecular mechanisms of dTCTP associated with lipopolysaccharides (LPS)-induced severe asthma. LPS stimulation increased dTCTP production by mast cells and dTCTP secretion during degranulation, and extracellular dTCTP subsequently increased the production of pro-inflammatory molecules, including IL-8, by airway epithelial cells without affecting mast cell activation. Furthermore, dimeric TCTP-binding peptide 2 (dTBP2), a dTCTP inhibitor peptide, selectively blocked the dTCTP-mediated signaling network from mast cells to epithelial cells and decreased IL-8 production through IkB induction and nuclear p65 export in airway epithelial cells. More importantly, dTBP2 efficiently attenuated LPS-induced severe airway inflammation in vivo, resulting in decreased immune cell infiltration and IL-17 production and attenuated dTCTP secretion. These results suggest that dTCTP produced by mast cells exacerbates airway inflammation through activation of airway epithelial cells in a paracrine signaling manner, and that dTBP2 is beneficial in the treatment of severe airway inflammation by blocking the dTCTP-mediated inflammatory cellular network.