RESUMEN
Autophagy is upregulated in adipose tissue (AT) from people with obesity. We showed that activation of the calcium-sensing receptor (CaSR) elevates proinflammatory cytokines through autophagy in preadipocytes. Our aim is to understand the role of CaSR on autophagy in AT from humans with obesity. We determined mRNA and protein levels of CaSR and markers of autophagy by qPCR and western blot in human visceral AT explants or isolated primary preadipocytes (60 donors: 72% female, 23-56% body fat). We also investigated their association with donors' anthropometric variables. Donors' % body fat and CaSR mRNA expression in AT were correlated (r = 0.44, p < 0.01). CaSR expression was associated with mRNA levels of the autophagy markers atg5 (r = 0.37, p < 0.01), atg7 (r = 0.29, p < 0.05) and lc3b (r = 0.40, p < 0.01). CaSR activation increased becn and atg7 mRNA expression in AT. CaSR activation also upregulated LC3II by ~50%, an effect abolished by the CaSR inhibitor. Spermine (CaSR agonist) regulates LC3II through the ERK1/2 pathway. Structural equation model analysis suggests a link between donors' AT CaSR expression, AT autophagy and expression of Tumor Necrosis Factor alpha TNF-α. CaSR expression in visceral AT is directly associated with % body fat, and CaSR activation may contribute to obesity-related disruption in AT autophagy.
Asunto(s)
Autofagia , Grasa Intraabdominal/metabolismo , Obesidad/metabolismo , Receptores Sensibles al Calcio/metabolismo , Adipocitos/metabolismo , Adulto , Proteína 7 Relacionada con la Autofagia/genética , Proteína 7 Relacionada con la Autofagia/metabolismo , Beclina-1/genética , Beclina-1/metabolismo , Células Cultivadas , Femenino , Humanos , Sistema de Señalización de MAP Quinasas , Masculino , Proteínas Asociadas a Microtúbulos/genética , Proteínas Asociadas a Microtúbulos/metabolismo , Persona de Mediana Edad , Factor de Necrosis Tumoral alfa/genética , Factor de Necrosis Tumoral alfa/metabolismoRESUMEN
INTRODUCTION AND OBJECTIVES: Endurance exercise (EXE) has emerged as a potent inducer of autophagy essential in maintaining cellular homeostasis in various tissues; however, the functional significance and molecular mechanisms of EXE-induced autophagy in the liver remain unclear. Thus, the aim of this study is to examine the signaling nexus of hepatic autophagy pathways occurring during acute EXE and a potential crosstalk between autophagy and apoptosis. MATERIALS AND METHODS: C57BL/6 male mice were randomly assigned to sedentary control group (CON, n=9) and endurance exercise (EXE, n=9). Mice assigned to EXE were gradually acclimated to treadmill running and ran for 60min per day for five consecutive days. RESULTS: Our data showed that EXE promoted hepatic autophagy via activation of canonical autophagy signaling pathways via mediating microtubule-associated protein B-light chain 3 II (LC3-II), autophagy protein 7 (ATG7), phosphorylated adenosine mono phosphate-activated protein kinase (p-AMPK), CATHEPSIN L, lysosome-associated membrane protein 2 (LAMP2), and a reduction in p62. Interestingly, this autophagy promotion concurred with enhanced anabolic activation via AKT-mammalian target of rapamycin (mTOR)-p70S6K signaling cascade and enhanced antioxidant capacity such as copper zinc superoxide dismutase (CuZnSOD), glutathione peroxidase (GPX), and peroxiredoxin 3 (PRX3), known to be as antagonists of autophagy. Moreover, exercise-induced autophagy was inversely related to apoptosis in the liver. CONCLUSIONS: Our findings indicate that improved autophagy and antioxidant capacity, and potentiated anabolic signaling may be a potent non-pharmacological therapeutic strategy against diverse liver diseases.
Asunto(s)
Apoptosis/fisiología , Autofagia/fisiología , Hígado/metabolismo , Condicionamiento Físico Animal/fisiología , Resistencia Física , Adenilato Quinasa/metabolismo , Animales , Antioxidantes/metabolismo , Proteína 7 Relacionada con la Autofagia/metabolismo , Catepsina L/metabolismo , Glutatión Peroxidasa/metabolismo , Hígado/patología , Proteína 2 de la Membrana Asociada a los Lisosomas/metabolismo , Lisosomas/metabolismo , Masculino , Ratones , Proteínas Asociadas a Microtúbulos/metabolismo , Peroxiredoxina III/metabolismo , Fosforilación , Proteínas Proto-Oncogénicas c-akt/metabolismo , Distribución Aleatoria , Proteínas Quinasas S6 Ribosómicas 70-kDa/metabolismo , Conducta Sedentaria , Transducción de Señal , Superóxido Dismutasa-1/metabolismo , Serina-Treonina Quinasas TOR/metabolismoRESUMEN
INTRODUCTION AND OBJECTIVES: The incidence of non-alcoholic fatty liver disease (NAFLD) is increasing. Previous studies indicated that Liraglutide, glucagon-like peptide-1 analogue, could regulate glucose homeostasis as a valuable treatment for Type 2 Diabetes. However, the precise effect of Liraglutide on NAFLD model in rats and the mechanism remains unknown. In this study, we investigated the molecular mechanism by which Liraglutide ameliorates hepatic steatosis in a high-fat diet (HFD)-induced rat model of NAFLD in vivo and in vitro. MATERIALS AND METHODS: NALFD rat models and hepatocyte steatosis in HepG2 cells were induced by HFD and palmitate fatty acid treatment, respectively. AMPK inhibitor, Compound C was added in HepG2 cells. Autophagy-related proteins LC3, Beclin1 and Atg7, and AMPK pathway-associated proteins were evaluated by Western blot and RT-PCR. RESULTS: Liraglutide enhanced autophagy as showed by the increased expression of the autophagy markers LC3, Beclin1 and Atg7 in HFD rats and HepG2 cells treated with palmitate fatty acid. In vitro, The AMPK inhibitor exhibited an inhibitory effect on Liraglutide-induced autophagy enhancement with the deceased expression of LC3, Beclin1 and Atg7. Additionally, Liraglutide treatment elevated AMPK levels and TSC1, decreased p-mTOR expression. CONCLUSIONS: Liraglutide could upregulate autophagy to decrease lipid over-accumulation via the AMPK/mTOR pathway.
Asunto(s)
Autofagia/efectos de los fármacos , Liraglutida/farmacología , Hígado/efectos de los fármacos , Enfermedad del Hígado Graso no Alcohólico/metabolismo , Adenilato Quinasa/efectos de los fármacos , Adenilato Quinasa/metabolismo , Animales , Autofagia/genética , Proteína 7 Relacionada con la Autofagia/efectos de los fármacos , Proteína 7 Relacionada con la Autofagia/genética , Proteína 7 Relacionada con la Autofagia/metabolismo , Beclina-1/efectos de los fármacos , Beclina-1/genética , Beclina-1/metabolismo , Dieta Alta en Grasa , Células Hep G2 , Humanos , Técnicas In Vitro , Hígado/metabolismo , Proteínas Asociadas a Microtúbulos/efectos de los fármacos , Proteínas Asociadas a Microtúbulos/genética , Proteínas Asociadas a Microtúbulos/metabolismo , Palmitatos/farmacología , Ratas , Serina-Treonina Quinasas TOR/efectos de los fármacos , Serina-Treonina Quinasas TOR/metabolismo , Proteína 1 del Complejo de la Esclerosis Tuberosa/efectos de los fármacos , Proteína 1 del Complejo de la Esclerosis Tuberosa/metabolismoRESUMEN
Melanoma incidence increases every year worldwide and is responsible for 80% of skin cancer deaths. Due to its metastatic potential and resistance to almost any treatments such as chemo, radio, immune and targeted-therapy, the patients still have a poor prognosis, especially at metastatic stage. Considering that, it is crucial to find new therapeutic approaches to overcome melanoma resistance. Here we investigated the effect of cisplatin (CDDP), one of the chemotherapeutic agents used for melanoma treatment, in association with nutritional deprivation in murine melanoma cell lines. Cell death and autophagy were evaluated after the treatment with cisplatin, nutritional deprivation and its association using an in vitro model of murine melanocytes malignant transformation to metastatic melanoma. Our results showed that nutritional deprivation augmented cell death induced by cisplatin in melanoma cells, especially at the metastatic subtype, with slight effects on melanocytes. Mechanistic studies revealed that although autophagy was present at high levels in basal conditions in melanoma cells, was not essential for cell death process that involved mitochondrial damage, reactive oxygen species production and possible glycolysis inhibition. In conclusion, nutritional shortage in combination with chemotherapeutic drugs as cisplatin can be a valuable new therapeutic strategy to overcome melanoma resistance.