RESUMO
Obesity often leads to obesity-related cardiac hypertrophy (ORCH), which is suppressed by zinc-induced inactivation of p38 mitogen-activated protein kinase (p38 MAPK). In this study, we investigated the mechanisms by which zinc inactivates p38 MAPK to prevent ORCH. Mice (4-week old) were fed either high fat diet (HFD, 60% kcal fat) or normal diet (ND, 10% kcal fat) containing variable amounts of zinc (deficiency, normal and supplement) for 3 and 6 months. P38 MAPK siRNA and the p38 MAPK inhibitor SB203580 were used to suppress p38 MAPK activity in vitro and in vivo, respectively. HFD activated p38 MAPK and increased expression of B-cell lymphoma/CLL 10 (BCL10) and caspase recruitment domain family member 9 (CARD9). These responses were enhanced by zinc deficiency and attenuated by zinc supplement. Administration of SB203580 to HFD mice or specific siRNA in palmitate-treated cardiomyocytes eliminated the HFD and zinc deficiency activation of p38 MAPK, but did not significantly impact the expression of BCL10 and CARD9. In cultured cardiomyocytes, inhibition of BCL10 expression by siRNA prevented palmitate-induced increased p38 MAPK activation and atrial natriuretic peptide (ANP) expression. In contrast, inhibition of p38 MAPK prevented ANP expression, but did not affect BCL10 expression. Deletion of metallothionein abolished the protective effect of zinc on palmitate-induced up-regulation of BCL10 and phospho-p38 MAPK. HFD and zinc deficiency synergistically induce ORCH by increasing oxidative stress-mediated activation of BCL10/CARD9/p38 MAPK signalling. Zinc supplement ameliorates ORCH through activation of metallothionein to repress oxidative stress-activated BCL10 expression and p38 MAPK activation.
Assuntos
Proteína 10 de Linfoma CCL de Células B/genética , Proteínas Adaptadoras de Sinalização CARD/genética , Cardiomegalia/tratamento farmacológico , Metalotioneína/genética , Proteínas Quinases p38 Ativadas por Mitógeno/genética , Animais , Cardiomegalia/etiologia , Cardiomegalia/genética , Cardiomegalia/patologia , Dieta Hiperlipídica , Suplementos Nutricionais , Regulação da Expressão Gênica/efeitos dos fármacos , Humanos , Imidazóis/administração & dosagem , Camundongos , Miócitos Cardíacos/efeitos dos fármacos , Obesidade/complicações , Obesidade/genética , Obesidade/patologia , Estresse Oxidativo/efeitos dos fármacos , Piridinas/administração & dosagem , RNA Interferente Pequeno/genética , Transdução de Sinais/efeitos dos fármacos , Zinco/administração & dosagem , Zinco/deficiênciaRESUMO
Childhood obesity often leads to cardiovascular diseases, such as obesity-related cardiac hypertrophy (ORCH), in adulthood, due to chronic cardiac inflammation. Zinc is structurally and functionally essential for many transcription factors; however, its role in ORCH and underlying mechanism(s) remain unclear and were explored here in mice with obesity induced with high-fat diet (HFD). Four week old mice were fed on either HFD (60%kcal fat) or normal diet (ND, 10% kcal fat) for 3 or 6 months, respectively. Either diet contained one of three different zinc quantities: deficiency (ZD, 10mg zinc per 4057kcal), normal (ZN, 30mg zinc per 4057kcal) or supplement (ZS, 90mg zinc per 4057kcal). HFD induced a time-dependent obesity and ORCH, which was accompanied by increased cardiac inflammation and p38 MAPK activation. These effects were worsened by ZD in HFD/ZD mice and attenuated by ZS in HFD/ZS group, respectively. Also, administration of a p38 MAPK specific inhibitor in HFD mice for 3 months did not affect HFD-induced obesity, but completely abolished HFD-induced, and zinc deficiency-worsened, ORCH and cardiac inflammation. In vitro exposure of adult cardiomyocytes to palmitate induced cell hypertrophy accompanied by increased p38 MAPK activation, which was heightened by zinc depletion with its chelator TPEN. Inhibition of p38 MAPK with its specific siRNA also prevented the effects of palmitate on cardiomyocytes. These findings demonstrate that ZS alleviates but ZD heightens cardiac hypertrophy in HFD-induced obese mice through suppressing p38 MAPK-dependent cardiac inflammatory and hypertrophic pathways.
Assuntos
Cardiomegalia/prevenção & controle , Deficiências Nutricionais/dietoterapia , Suplementos Nutricionais , Sistema de Sinalização das MAP Quinases , Obesidade/fisiopatologia , Zinco/deficiência , Proteínas Quinases p38 Ativadas por Mitógeno/metabolismo , Animais , Cardiomegalia/etiologia , Cardiomegalia/metabolismo , Cardiomegalia/fisiopatologia , Células Cultivadas , Quelantes/efeitos adversos , Deficiências Nutricionais/complicações , Deficiências Nutricionais/imunologia , Dieta Hiperlipídica/efeitos adversos , Ativação Enzimática/efeitos dos fármacos , Ácidos Graxos não Esterificados/efeitos adversos , Sistema de Sinalização das MAP Quinases/efeitos dos fármacos , Masculino , Camundongos Endogâmicos C57BL , Miócitos Cardíacos/citologia , Miócitos Cardíacos/efeitos dos fármacos , Miócitos Cardíacos/imunologia , Miócitos Cardíacos/metabolismo , Obesidade/complicações , Obesidade/etiologia , Obesidade/imunologia , Ácido Palmítico/efeitos adversos , Inibidores de Proteínas Quinases/uso terapêutico , Interferência de RNA , Índice de Gravidade de Doença , Zinco/química , Zinco/uso terapêutico , Proteínas Quinases p38 Ativadas por Mitógeno/antagonistas & inibidores , Proteínas Quinases p38 Ativadas por Mitógeno/genéticaRESUMO
AIMS/HYPOTHESIS: Diabetic nephropathy is the leading cause of end-stage renal disease. Previously we reported that C66, a novel analogue of curcumin with a very high bioavailability, ameliorated diabetic nephropathy in mice, with little known about the mechanism. The present study aimed to define the mechanism by which C66 ameliorates diabetic nephropathy. METHODS: Our aim was to discover whether C66 acts through the activation of nuclear factor (erythroid-derived 2)-like 2 (NFE2L2 or NRF2), which governs the antioxidant response. Streptozotocin-induced Nrf2 (also known as Nfe2l2)-knockout and wild-type (WT) diabetic mice were treated with C66. To determine whether the actions of C66 on NRF2 are mediated by microRNA (miR)-200a, WT diabetic mice were treated with C66 in the presence or absence of an in vivo miR-200a inhibitor (locked nucleic acid-modified anti-miR-200a [LNA-200a]) for 6 months. To determine whether miR-21 downregulation provided an NRF2-independent basis for C66 protection, Nrf2-knockout diabetic mice were treated with either C66 or an inhibitor of miR-21 (locked nucleic acid-modified anti-miR-21 [LNA-21]). RESULTS: Deletion of Nrf2 partially abolished diabetic nephropathy protection by C66, confirming the requirement of NRF2 for this protection. Diabetic mice, but not C66-treated diabetic mice, developed significant albuminuria, renal oxidative damage and fibrosis. C66 upregulated renal miR-200a, inhibited kelch-like ECH-associated protein 1 and induced NRF2 function, effects that were prevented by LNA-200a. However, LNA-200a only partially reduced the protection afforded by C66, suggesting the existence of miR-200a/NRF2-independent mechanisms for C66 protection. C66 was also found to inhibit diabetes induction of miR-21. Both C66 and LNA-21 produced similar reductions in miR-21, albuminuria and renal fibrosis. CONCLUSIONS/INTERPRETATION: The present study indicates that in addition to upregulating NRF2 by increasing miR-200a, C66 also protects against diabetic nephropathy by inhibiting miR-21.
Assuntos
Curcumina/uso terapêutico , Nefropatias Diabéticas/metabolismo , MicroRNAs/metabolismo , Fator 2 Relacionado a NF-E2/metabolismo , Animais , Pressão Sanguínea/genética , Pressão Sanguínea/fisiologia , Western Blotting , Diabetes Mellitus Experimental/tratamento farmacológico , Diabetes Mellitus Experimental/metabolismo , Diabetes Mellitus Experimental/patologia , Nefropatias Diabéticas/tratamento farmacológico , Nefropatias Diabéticas/patologia , Heterozigoto , Proteína 1 Associada a ECH Semelhante a Kelch/genética , Proteína 1 Associada a ECH Semelhante a Kelch/metabolismo , Masculino , Camundongos , Camundongos Endogâmicos C57BL , Camundongos Knockout , MicroRNAs/genética , Fator 2 Relacionado a NF-E2/genéticaRESUMO
Plectranthus excisus is widely distributed throughout northeast China. Its active ingredient, diterpenoids, exhibits significant antitumor effects. The present study examined the antitumor effects of diterpenoid B (DB), derived from Plectranthus excisus, and demonstrated that DB inhibited the proliferation of tumor cells by inhibiting the cell cycle. Reverse transcriptionquantitative polymerase chain reaction and western blot analysis were used to determine mRNA and protein expression levels, respectively. The results revealed that exposure to DB increased the expression levels of the transformation associated, protein 53, and cyclindependent kinase inhibitor 1A, and decreased the expression of cyclindependent kinase 2. The results of the present study demonstrated that DB can inhibit cell cycle progression and, therefore, offers potential as a beneficial antitumor drug.