RESUMEN
Endogenous hydrogen sulfide (H2S) affects cholesterol homeostasis and liver X receptor α (LXRα) expression. However, whether low-density lipoprotein (LDL) receptor (LDLR), a key player in cholesterol homeostasis, is regulated by exogenous H2S through LXRα signaling has not been determined. We investigated the effects of sodium hydrosulfide (NaHS, H2S donor) on LDLR expression in the presence or absence of LXR agonists, T0901317 or GW3965 in HepG2 cells. We found that H2S strongly accumulated LDLR precursor in the presence of T0901317. Hence, LDLR transcription and the genes involved in LDLR precursor maturation and degradation were studied. T0901317 increased the LDLR mRNA level, whereas H2S did not affect LDLR transcription. H2S had no significant effect on the expression of LXRα and inducible degrader of LDLR (IDOL). H2S and T0901317 altered mRNA levels of several enzymes for N- and O-glycosylation and endoplasmic reticulum (ER) chaperones assisting LDLR maturation, but did not affect their protein levels. H2S decreased proprotein convertase subtilisin/kexin type 9 (PCSK9) protein levels and its mRNA level elevated by T0901317. T0901317 with PCSK9 siRNA also accumulated LDLR precursor as did T0901317 with H2S. High glucose increased PCSK9 protein levels and attenuated LDLR precursor accumulation induced by T0901317 with H2S. Taken together, H2S accumulates LDLR precursor by downregulating PCSK9 expression but not through the LXRα-IDOL pathway, LDLR transcriptional activation, or dysfunction of glycosylation enzymes and ER chaperones. These results also indicate that PCSK9 plays an important role in LDLR maturation in addition to its well-known effect on the degradation of LDLR mature form.
Asunto(s)
Sulfuro de Hidrógeno/metabolismo , Receptores X del Hígado/metabolismo , Proproteína Convertasa 9/metabolismo , Receptores de LDL/metabolismo , Benzoatos/farmacología , Bencilaminas/farmacología , Línea Celular Tumoral , Colesterol/metabolismo , Retículo Endoplásmico/fisiología , Glicosilación/efectos de los fármacos , Células Hep G2 , Homeostasis/fisiología , Humanos , Hidrocarburos Fluorados/farmacología , Receptores X del Hígado/agonistas , Proproteína Convertasa 9/genética , Interferencia de ARN , ARN Mensajero/genética , ARN Interferente Pequeño/genética , Sulfuros/farmacología , Sulfonamidas/farmacología , Transcripción Genética/efectos de los fármacos , Activación Transcripcional/genéticaRESUMEN
Aims. The study was designed to explore whether hydrogen sulphide (H2S) and nitric oxide (NO) generation changed in D-galactose- (D-gal-) induced ageing, the possible effects of exogenous H2S supplementation, and related mechanisms. Results. In D-gal-induced senescent mice, both H2S and NO levels in the heart, liver, and kidney tissues were decreased significantly. A similar trend was observed in D-gal-challenged human umbilical vein endothelial cells (HUVECs). Sustained H2S donor (NaHS) treatment for 2 months elevated H2S and NO levels in these mice, and during this period, the D-gal-induced senescent phenotype was reversed. The protective effect of NaHS is associated with a decrease in reactive oxygen species levels and an increase in antioxidants, such as glutathione, and superoxide dismutase and glutathione peroxidase activities. Increased expression of the H2S-producing enzymes cystathionine γ-lyase (CSE) and cystathionine-ß-synthase (CBS) in the heart, liver, and kidney tissues was observed in the NaHS-treated groups. NaHS supplementation also significantly postponed D-gal-induced HUVEC senescence. Conclusions. Endogenous hydrogen sulphide production in both ageing mice and endothelial cells is insufficient. Exogenous H2S can partially rescue ageing-related dysfunction by inducing endogenous H2S and NO production and reducing oxidative stress. Restoring endogenous H2S production may contribute to healthy ageing, and H2S may have antiageing effects.
Asunto(s)
Senescencia Celular/efectos de los fármacos , Galactosa/farmacología , Sulfuro de Hidrógeno/metabolismo , Óxido Nítrico/biosíntesis , Sulfuros/farmacología , Animales , Citoprotección/efectos de los fármacos , Células Endoteliales de la Vena Umbilical Humana/efectos de los fármacos , Humanos , Masculino , Ratones Endogámicos C57BL , Modelos Biológicos , Óxido Nítrico Sintasa de Tipo III/metabolismo , Estrés Oxidativo/efectos de los fármacos , Fosforilación/efectos de los fármacos , Proteínas Proto-Oncogénicas c-akt/metabolismo , Reproducibilidad de los ResultadosRESUMEN
Aims. The study aimed to examine whether hydrogen sulfide (H2S) generation changed in the kidney of the ageing mouse and its relationship with impaired kidney function. Results. H2S levels in the plasma, urine, and kidney decreased significantly in ageing mice. The expression of two known H2S-producing enzymes in kidney, cystathionine γ-lyase (CSE) and cystathionine-ß-synthase (CBS), decreased significantly during ageing. Chronic H2S donor (NaHS, 50 µmol/kg/day, 10 weeks) treatment could alleviate oxidative stress levels and renal tubular interstitial collagen deposition. These protective effects may relate to transcription factor Nrf2 activation and antioxidant proteins such as HO-1, SIRT1, SOD1, and SOD2 expression upregulation in the ageing kidney after NaHS treatment. Furthermore, the expression of H2S-producing enzymes changed with exogenous H2S administration and contributed to elevated H2S levels in the ageing kidney. Conclusions. Endogenous hydrogen sulfide production in the ageing kidney is insufficient. Exogenous H2S can partially rescue ageing-related kidney dysfunction by reducing oxidative stress, decreasing collagen deposition, and enhancing Nrf2 nuclear translocation. Recovery of endogenous hydrogen sulfide production may also contribute to the beneficial effects of NaHS treatment.
Asunto(s)
Envejecimiento/metabolismo , Sulfuro de Hidrógeno/metabolismo , Riñón/efectos de los fármacos , Sulfuros/farmacología , Transporte Activo de Núcleo Celular , Factores de Edad , Envejecimiento/sangre , Envejecimiento/patología , Envejecimiento/orina , Animales , Apoptosis/efectos de los fármacos , Colágeno/metabolismo , Cistationina betasintasa/metabolismo , Cistationina gamma-Liasa/metabolismo , Relación Dosis-Respuesta a Droga , Activación Enzimática , Fibrosis , Hemo-Oxigenasa 1/metabolismo , Sulfuro de Hidrógeno/sangre , Sulfuro de Hidrógeno/orina , Riñón/metabolismo , Riñón/patología , Masculino , Proteínas de la Membrana/metabolismo , Ratones Endogámicos C57BL , Factor 2 Relacionado con NF-E2/metabolismo , Estrés Oxidativo/efectos de los fármacos , Transducción de Señal/efectos de los fármacos , Sirtuina 1/metabolismo , Sulfuros/metabolismo , Superóxido Dismutasa/metabolismo , Superóxido Dismutasa-1/metabolismoRESUMEN
Aims. To examine the expression patterns of hydrogen sulphide- (H2S-) producing enzymes in ischaemic heart tissue and plasma levels of H2S after 2 weeks of NaHS treatment after myocardial infarction (MI) and to clarify the role of endogenous H2S in the MI process. Results. After MI surgery, 2 weeks of treatment with the H2S donor NaHS alleviated ischaemic injury. Meanwhile, in ischemia myocardium, three H2S-producing enzymes, cystathionine γ-lyase (CSE), cystathionine-ß-synthase (CBS), and 3-mercaptopyruvate sulfurtransferase (3-MST) significantly increased. Plasma H2S levels were also elevated. In vitro, NaHS treatment protected cardiomyocytes from hypoxic injury and raised CBS levels in a concentration-dependent manner. Different from in vivo results, however, CSE or 3-MST expression did not change. NaHS treatment increased the activity of CSE/CBS but not of 3-MST. When CSE was either knocked down (in vitro) or knocked out (in vivo), H2S levels significantly decreased, which subsequently exacerbated the ischaemic injury. Meanwhile, the expressions of CBS and 3-MST increased due to compensation. Conclusions. Exogenous H2S treatment changed the expressions of three H2S-producing enzymes and H2S levels after MI, suggesting a new and indirect regulatory mechanism for H2S production and its contribution to cardiac protection. Endogenous H2S plays an important role in protecting ischaemic tissue after MI.
Asunto(s)
Sulfuro de Hidrógeno/metabolismo , Infarto del Miocardio/enzimología , Sulfuros/farmacología , Animales , Hipoxia de la Célula/efectos de los fármacos , Cistationina betasintasa/metabolismo , Cistationina gamma-Liasa/metabolismo , Citoprotección/efectos de los fármacos , Sulfuro de Hidrógeno/sangre , Masculino , Ratones Endogámicos C57BL , Infarto del Miocardio/patología , Infarto del Miocardio/prevención & control , Isquemia Miocárdica/patología , Miocardio/patología , Miocitos Cardíacos/efectos de los fármacos , Miocitos Cardíacos/metabolismo , Miocitos Cardíacos/patología , Ratas Sprague-Dawley , Sulfurtransferasas/metabolismoRESUMEN
Aims. To examine whether hydrogen sulfide (H2S) generation changed in ageing diabetic mouse hearts. Results. Compared to mice that were fed tap water only, mice that were fed 30% fructose solution for 15 months exhibited typical characteristics of a severe diabetic phenotype with cardiac hypertrophy, fibrosis, and dysfunction. H2S levels in plasma, heart tissues, and urine were significantly reduced in these mice as compared to those in controls. The expression of the H2S-generating enzymes, cystathionine γ-lyase and 3-mercaptopyruvate sulfurtransferase, was significantly decreased in the hearts of fructose-fed mice, whereas cystathionine-ß-synthase levels were significantly increased. Conclusion. Our results suggest that this ageing diabetic mouse model developed diabetic cardiomyopathy and that H2S levels were reduced in the diabetic heart due to alterations in three H2S-producing enzymes, which may be involved in the pathogenesis of diabetic cardiomyopathy.