RESUMO
Abstract This study aimed to investigate the role and signaling pathways of β3-AR in myocardial ischemia/reperfusion (I/R) injury, which is one of the leading causes of death worldwide. 47 male rats were randomly divided into two main groups to evaluate infarct size and molecular parameters. Rats in both groups were randomly divided into 4 groups. Control (sham), I/R (30 min ischemia/120 min reperfusion), BRL37344 (BRL) (A) (5 µg/kg single-dose pre-treatment (preT) before I/R) and BRL (B) (5 µg/kg/day preT for 10 days before I/R). Infarct size was determined with triphenyltetrazolium chloride staining and analyzed with ImageJ program. The levels of AMPK, SIRT1, mTOR, and p70SK6 responsible for cellular energy and autophagy were evaluated by western blot. Infarct size increased in the I/R group (44.84 ± 1.47%) and reduced in the single-dose and 10-day BRL-treated groups (32.22 ± 1.57%, 29.65 ± 0.55%; respectively). AMPK and SIRT1 levels were decreased by I/R but improved in the treatment groups. While mTOR and p70S6K levels increased in the I/R group, they decreased with BRL preT. BRL preT protects the heart against I/R injury. These beneficial effects are mediated in part by activation of AMPK and SIRT1, inhibition of mTOR and p70S6K, and consequently protected autophagy.
Assuntos
Animais , Masculino , Ratos , Autofagia , Traumatismo por Reperfusão Miocárdica/patologia , Agonistas Adrenérgicos , Isquemia/patologia , Western Blotting/métodos , Isquemia Miocárdica/patologia , Proteínas Quinases S6 Ribossômicas 70-kDa/antagonistas & inibidores , Sirtuína 1/classificação , Coração/fisiopatologia , InfartoRESUMO
The fibrotic process could be easily defined as a pathological excess of extracellular matrix deposition, leading to disruption of tissue architecture and eventually loss of function; however, this process involves a complex network of several signal transduction pathways. Virtually almost all organs could be affected by fibrosis, the most affected are the liver, lung, skin, kidney, heart, and eyes; in all of them, the transforming growth factor-beta (TGF-ß) has a central role. The canonical and non-canonical signal pathways of TGF-ß impact the fibrotic process at the cellular and molecular levels, inducing the epithelial-mesenchymal transition (EMT) and the induction of profibrotic gene expression with the consequent increase in proteins such as alpha-smooth actin (α-SMA), fibronectin, collagen, and other extracellular matrix proteins. Recently, it has been reported that some molecules that have not been typically associated with the fibrotic process, such as nicotinamide adenine dinucleotide phosphate (NADPH) oxidase 4 (NOX4), mammalian target of rapamycin (mTOR), histone deacetylases (HDAC), and sphingosine-1 phosphate (S1P); are critical in its development. In this review, we describe and discuss the role of these new players of fibrosis and the convergence with TGF-ß signaling pathways, unveiling new insights into the panorama of fibrosis that could be useful for future therapeutic targets.
Assuntos
Esfingosina , Fator de Crescimento Transformador beta , Fibrose , Amigos , Histona Desacetilases , Humanos , NADPH Oxidase 4 , Esfingosina/metabolismo , Serina-Treonina Quinases TOR , Fator de Crescimento Transformador beta/metabolismo , Fator de Crescimento Transformador beta1/metabolismoRESUMO
Cancer cells characteristically have a high proliferation rate. Because tumor growth depends on energy-consuming anabolic processes, including biosynthesis of protein, lipid, and nucleotides, many tumor-associated conditions, including intermittent oxygen deficiency due to insufficient vascularization, oxidative stress, and nutrient deprivation, results from fast growth. To cope with these environmental stressors, cancer cells, including cancer stem cells, must adapt their metabolism to maintain cellular homeostasis. It is well- known that cancer stem cells (CSC) reprogram their metabolism to adapt to live in hypoxic niches. They usually change from oxidative phosphorylation to increased aerobic glycolysis even in the presence of oxygen. However, as opposed to most differentiated cancer cells relying on glycolysis, CSCs can be highly glycolytic or oxidative phosphorylation-dependent, displaying high metabolic plasticity. Although the influence of the metabolic and nutrient-sensing pathways on the maintenance of stemness has been recognized, the molecular mechanisms that link these pathways to stemness are not well known. Here in this review, we describe the most relevant signaling pathways involved in nutrient sensing and cancer cell survival. Among them, Adenosine monophosphate (AMP)-activated protein kinase (AMPK) pathway, mTOR pathway, and Hexosamine Biosynthetic Pathway (HBP) are critical sensors of cellular energy and nutrient status in cancer cells and interact in complex and dynamic ways.
Assuntos
Metabolismo Energético/fisiologia , Células-Tronco Neoplásicas/metabolismo , Transdução de Sinais/fisiologia , Animais , Hexosaminas/metabolismo , Humanos , Estresse Oxidativo/fisiologia , Serina-Treonina Quinases TOR/metabolismoRESUMO
The present study verified the responses of proteins related to the autophagy pathway after 10 h of fast with resistance exercise and protein ingestion in skeletal muscle and liver samples. The rats were distributed into five experimental groups: control (CT; sedentary and without gavage after fast), exercise immediately (EXE-imm; after fast, rats were submitted to the resistance protocol and received water by gavage immediately after exercise), exercise after 1 h (EXE-1h; after fast, rats were submitted to the resistance protocol and received water by gavage 1 h after exercise), exercise and supplementation immediately after exercise (EXE/Suppl-imm; after fast, rats were submitted to the resistance protocol and received a mix of casein: whey protein 1:1 (w/w) by gavage immediately after exercise), exercise and supplementation 1 h after exercise (EXE/Suppl-1h; after fast, rats were submitted to the resistance protocol and received a mix of casein: whey protein 1:1 (w/w) by gavage 1 h after exercise). In summary, the current findings show that the combination of fasting, acute resistance exercise, and protein blend ingestion (immediately or 1 h after the exercise stimulus) increased the serum levels of leucine, insulin, and glucose, as well as the autophagy protein contents in skeletal muscle, but decreased other proteins related to the autophagic pathway in the liver. These results deserve further mechanistic investigations since athletes are combining fasting with physical exercise to enhance health and performance outcomes.
Assuntos
Autofagia , Biomarcadores/metabolismo , Proteínas Alimentares/administração & dosagem , Jejum/fisiologia , Fígado/metabolismo , Músculo Esquelético/metabolismo , Condicionamento Físico Animal , Treinamento Resistido , Albuminas/metabolismo , Animais , Autofagia/efeitos dos fármacos , Autofagia/genética , Glicemia/metabolismo , Peso Corporal/efeitos dos fármacos , Proteínas Alimentares/farmacologia , Ingestão de Alimentos , Jejum/sangue , Regulação da Expressão Gênica/efeitos dos fármacos , Insulina/sangue , Leucina/sangue , Fígado/efeitos dos fármacos , Masculino , Músculo Esquelético/efeitos dos fármacos , Tamanho do Órgão/efeitos dos fármacos , RNA Mensageiro/genética , RNA Mensageiro/metabolismo , Ratos Wistar , Triglicerídeos/sangueRESUMO
Dysregulation of mammalian target of rapamycin (mTOR) in hepatocellular carcinoma (HCC) represents a valuable treatment target. Recent studies have developed a highly-selective and potent mTOR kinase inhibitor, CZ415. Here, we showed that nM concentrations of CZ415 efficiently inhibited survival and induced apoptosis in HCC cell lines (HepG2 and Huh-7) and primary-cultured human HCC cells. Meanwhile, CZ415 inhibited proliferation of HCC cells, more potently than mTORC1 inhibitors (rapamycin and RAD001). CZ415 was yet non-cytotoxic to the L02 human hepatocytes. Mechanistic studies showed that CZ415 disrupted assembly of mTOR complex 1 (mTORC1) and mTORC2 in HepG2 cells. Meanwhile, activation of mTORC1 (p-S6K1) and mTORC2 (p-AKT, Ser-473) was almost blocked by CZ415. In vivo studies revealed that oral administration of CZ415 significantly suppressed HepG2 xenograft tumor growth in severe combined immuno-deficient (SCID) mice. Activation of mTORC1/2 was also largely inhibited in CZ415-treated HepG2 tumor tissue. Together, these results show that CZ415 blocks mTORC1/2 activation and efficiently inhibits HCC cell growth in vitro and in vivo.
Assuntos
Antineoplásicos/farmacologia , Carcinoma Hepatocelular/enzimologia , Carcinoma Hepatocelular/patologia , Óxidos S-Cíclicos/farmacologia , Neoplasias Hepáticas/enzimologia , Neoplasias Hepáticas/patologia , Compostos de Fenilureia/farmacologia , Inibidores de Proteínas Quinases/farmacologia , Serina-Treonina Quinases TOR/antagonistas & inibidores , Antineoplásicos/síntese química , Antineoplásicos/química , Apoptose/efeitos dos fármacos , Carcinoma Hepatocelular/tratamento farmacológico , Ciclo Celular/efeitos dos fármacos , Proliferação de Células/efeitos dos fármacos , Óxidos S-Cíclicos/síntese química , Óxidos S-Cíclicos/química , Relação Dose-Resposta a Droga , Ensaios de Seleção de Medicamentos Antitumorais , Células Hep G2 , Humanos , Neoplasias Hepáticas/tratamento farmacológico , Compostos de Fenilureia/síntese química , Compostos de Fenilureia/química , Inibidores de Proteínas Quinases/síntese química , Inibidores de Proteínas Quinases/química , Relação Estrutura-Atividade , Serina-Treonina Quinases TOR/metabolismo , Células Tumorais CultivadasRESUMO
cAMP is a second messenger well documented to be involved in the phosphorylation of PKA, MAP kinase, and histone H3 (H3). Early, we reported that cAMP also induced H3 dephosphorylation in a variety of proliferating cell lines. Herein, it is shown that cAMP elicits a biphasic H3 dephosphorylation independent of PKA activation in cycling cells. H89, a potent inhibitor of PKA catalytic sub-unite, could not abolish this effect. Additionally, H89 induces a rapid and biphasic H3 serine 10 dephosphorylation, while a decline in the basal phosphorylation of CREB/ATF-1 is observed. Rp-cAMPS, an analog of cAMP and specific inhibitor of PKA, is unable to suppress cAMP-mediated H3 dephosphorylation, whereas Rp-cAMPS effectively blocks CREB/ATF-1 hyper-phosphorylation by cAMP and its inducers. Interestingly, cAMP exerts a rapid and profound H3 dephosphorylation at much lower concentration (50-fold lower, 0.125 mM) than the concentration required for maximal CREB/ATF-1 phosphorylation (5 mM). Much higher cAMP concentration is required to fully induce CREB/ATF-1 gain in phosphate (5 mM), which correlates with the inhibition of H3 dephosphorylation. Also, the dephosphorylation of H3 does not overlap at onset of MAP kinase phosphorylation pathways, p38 and ERK. Surprisingly, rapamycin (an mTOR inhibitor), cAMP, and its natural inducer isoproterenol, elicit identical dephosphorylation kinetics on both S6K1 ribosomal kinase (a downstream mTOR target) and H3. Finally, cAMP-induced H3 dephosphorylation is PP1/2-dependent. The results suggest that a pathway, requiring much lower cAMP concentration to that required for CREB/ATF-1 hyper-phosphorylation, is responsible for histone H3 dephosphorylation and may be linked to mTOR down regulation.