RESUMEN
BACKGROUND: There is a need for novel treatments for neuroblastoma, despite the emergence of new biological and immune treatments, since refractory pediatric neuroblastoma is still a medical challenge. Phyto cannabinoids and their hemisynthetic derivatives have shown evidence supporting their anticancer potential. The aim of this research was to examine Phytocannabinoids or hemisynthetic cannabinoids, which reduce the SHSY-5Y, neuroblastoma cell line's viability. METHODS: Hexane and acetyl acetate extracts were produced starting with Cannabis sativa L. as raw material, then, 9-tetrahidrocannabinol, its acid counterpart and CBN were isolated. In addition, acetylated derivatives of THC and CBN were synthesized. The identification and purity of the chemicals was determined by High Performance Liquid Chromatography and 1H y 13C Magnetic Nuclear Resonance. Then, the capacity to affect the viability of SHSY-5Y, a neuroblastoma cell line, was examined using the resazurin method. Finally, to gain insight into the mechanism of action of the extracts, phytocannabinoids and acetylated derivatives on the examined cells, a caspase 3/7 determination was performed on cells exposed to these compounds. RESULTS: The structure and purity of the isolated compounds was demonstrated. The extracts, the phytocannabinoids and their acetylated counterparts inhibited the viability of the SHSY 5Y cells, being CBN the most potent of all the tested molecules with an inhibitory concentration of 50 percent of 9.5 µM. CONCLUSION: Each of the evaluated molecules exhibited the capacity to activate caspases 3/7, indicating that at least in part, the cytotoxicity of the tested phytocannabinoids and their hemi-synthetic derivatives is mediated by apoptosis.
Asunto(s)
Cannabinoides , Cannabis , Caspasa 3 , Supervivencia Celular , Neuroblastoma , Extractos Vegetales , Humanos , Cannabis/química , Extractos Vegetales/farmacología , Extractos Vegetales/química , Línea Celular Tumoral , Neuroblastoma/tratamiento farmacológico , Supervivencia Celular/efectos de los fármacos , Caspasa 3/metabolismo , Caspasa 3/efectos de los fármacos , Cannabinoides/farmacología , Cannabinoides/química , Caspasa 7/metabolismo , Apoptosis/efectos de los fármacos , Acetilación/efectos de los fármacos , Cromatografía Líquida de Alta PresiónRESUMEN
In this study, we aimed to evaluate two sets of sesquiterpene-aryl derivatives linked by an ester bond, their cytotoxic activities, and their capacity to activate caspases 3/7 and inhibit human topoisomerase I (TOP1). A total of 13 compounds were synthesized from the natural sesquiterpene (-)-drimenol and their cytotoxic activity was evaluated in vitro against three cancer cell lines: PC-3 (prostate cancer), HT-29 (colon cancer), MCF-7 (breast cancer), and an immortalized non-tumoral cell line (MCF-10). From the results, it was observed that 6a was the most promising compound due to its cytotoxic effect on three cancer cell lines and its selectivity, 6a was 100-fold more selective than 5-FU in MCF-7 and 20-fold in PC-3. It was observed that 6a also induced apoptosis by caspases 3/7 activity using a Capsase-Glo-3/7 assay kit and inhibited TOP1. A possible binding mode of 6a in a complex with TOP1-DNA was proposed by docking and molecular dynamics studies. In addition, 6a was predicted to have a good pharmacokinetic profile for oral administration. Therefore, through this study, it was demonstrated that the drimane scaffold should be considered in the search of new antitumoral agents.
Asunto(s)
Antineoplásicos , Sesquiterpenos , Humanos , Línea Celular Tumoral , ADN-Topoisomerasas de Tipo I/metabolismo , Ésteres/farmacología , Antineoplásicos/química , Sesquiterpenos/farmacología , Apoptosis , Caspasas/metabolismo , Ensayos de Selección de Medicamentos Antitumorales , Simulación del Acoplamiento Molecular , Proliferación Celular , Relación Estructura-Actividad , Estructura MolecularRESUMEN
Cardiac myofibroblast (CMF) are non-muscle cardiac cells that play a crucial role in wound healing and in pathological remodeling. These cells are mainly derived of cardiac fibroblast (CF) differentiation mediated by TGF-ß1. Evidence suggests that bradykinin (BK) regulates cardiac fibroblast function in the heart. Both B1 and B2 kinin receptors (B1R and B2R, respectively) mediate the biological effects of kinins. We recently showed that both receptors are expressed in CMF and its stimulation decreases collagen secretion. Whether TGF-ß1 regulates B1R and B2R expression, and how these receptors control antifibrotic activity in CMF remains poorly understood. In this work, we sought to study, the regulation of B1R expression in cultured CMF mediated by TGF-ß1, and the molecular mechanisms involved in B1R activation on CMF intracellular collagen type-I levels. Cardiac fibroblast-primary culture was obtained from neonatal rats. Hearts were digested and CFs were attached to dishes and separated from cardiomyoctes. CMF were obtained from CF differentiation with TGF-ß1 5 ng/mL. CF and CMF were treated with B1R and B2R agonists and with TGF-ß1 at different times and concentrations, in the presence or absence of chemical inhibitors, to evaluate signaling pathways involved in B1R expression, collagen type-I and prostacyclin levels. B1R and collagen type-I levels were evaluated by western blot. Prostacyclin levels were quantified by an ELISA kit. TGF-ß1 increased B1R expression via TGFß type I receptor kinase (ALK5) activation and its subsequent signaling pathways involving Smad2, p38, JNK and ERK1/2 activation. Moreover, in CMF, the activation of B1R and B2R by their respective agonists, reduced collagen synthesis. This effect was mediated by the canonical signaling pathway; phospholipase C (PLC), protein kinase C (PKC), phospholipase A2 (PLA2), COX-2 activation and PGI2 secretion and its autocrine effect. TGF-ß1 through ALK5, Smad2, p38, JNK and ERK1/2 increases B1R expression; whereas in CMF, B1R and B2R activation share common signaling pathways for reducing collagen synthesis.
Asunto(s)
Miocardio/citología , Miofibroblastos/citología , Receptor de Bradiquinina B1/metabolismo , Factor de Crecimiento Transformador beta1/metabolismo , Regulación hacia Arriba , Animales , Animales Recién Nacidos , Diferenciación Celular , Células Cultivadas , Colágeno Tipo I/metabolismo , Epoprostenol/metabolismo , Regulación de la Expresión Génica , Miofibroblastos/metabolismo , Ratas , Receptor Tipo I de Factor de Crecimiento Transformador beta/metabolismo , Transducción de Señal/efectos de los fármacosRESUMEN
Cardiac fibroblasts (CF) act as sentinel cells responding to chemokines, cytokines and growth factors released in cardiac tissue in cardiac injury events, such as myocardial infarction (MI). Cardiac injury involves the release of various damage-associated molecular patterns (DAMPs) including heparan sulfate (HS), a constituent of the extracellular matrix (ECM), through the TLR4 receptor activation triggering a strong inflammatory response, inducing leukocytes recruitment. This latter cells are responsible of clearing cell debris and releasing cytokines that promote CF differentiation to myofibroblast (CMF), thus initiating scar formation. CF were isolated from adult male rats and subsequently stimulated with HS or LPS, in the presence or absence of chemical inhibitors, to evaluate signaling pathways involved in ICAM-1 and VCAM-1 expression. siRNA against ICAM-1 and VCAM-1 were used to evaluate participation of these adhesion molecules on leukocytes recruitment. HS through TLR4, PI3K/AKT and NF-ΚB increased ICAM-1 and VCAM-1 expression, which favored the adhesion of spleen mononuclear cells (SMC) and bone marrow granulocytes (PMN) to CF. These effects were prevented by siRNA against ICAM-1 and VCAM-1. Co-culture of CF with SMC increased α-SMA expression, skewing CF towards a pro-fibrotic phenotype, while CF pretreatment with HS partially reverted this effect. CONCLUSION: These data show the dual role of HS during the initial stages of wound healing. Initially, HS enhance the pro-inflammatory role of CF increasing cytokines secretion; and later, by increasing protein adhesion molecules allows the adhesion of SMC on CF, which trigger CF-to-CMF differentiation.
Asunto(s)
Adhesión Celular/efectos de los fármacos , Fibroblastos/efectos de los fármacos , Heparitina Sulfato/farmacología , Molécula 1 de Adhesión Intercelular/metabolismo , Leucocitos/efectos de los fármacos , Miocardio/citología , Molécula 1 de Adhesión Celular Vascular/metabolismo , Animales , Células Cultivadas , Fibroblastos/fisiología , Regulación de la Expresión Génica/efectos de los fármacos , Molécula 1 de Adhesión Intercelular/genética , Leucocitos/fisiología , Masculino , Miocardio/metabolismo , Miofibroblastos/efectos de los fármacos , Miofibroblastos/fisiología , Ratas , Ratas Sprague-Dawley , Transducción de Señal/efectos de los fármacos , Transducción de Señal/genética , Regulación hacia Arriba/efectos de los fármacos , Regulación hacia Arriba/genética , Molécula 1 de Adhesión Celular Vascular/genéticaRESUMEN
The heart must function continuously as it is responsible for both supplying oxygen and nutrients throughout the entire body, as well as for the transport of waste products to excretory organs. When facing either a physiological or pathological increase in cardiac demand, the heart undergoes structural and functional remodeling as a means of adapting to increased workload. These adaptive responses can include changes in gene expression, protein composition, and structure of sub-cellular organelles involved in energy production and metabolism. Mitochondria are essential for cardiac function, as they supply the ATP necessary to support continuous cycles of contraction and relaxation. In addition, mitochondria carry out other important processes, including synthesis of essential cellular components, calcium buffering, and initiation of cell death signals. Not surprisingly, mitochondrial dysfunction has been linked to several cardiovascular disorders, including hypertension, cardiac hypertrophy, ischemia/reperfusion and heart failure. The present chapter will discuss how changes in mitochondrial cristae structure, fusion/fission dynamics, fatty acid oxidation, ATP production, and the generation of reactive oxygen species might impact cardiac structure and function, particularly in the context of pathological hypertrophy and fibrotic response. In addition, the mechanistic role of mitochondria in autophagy and programmed cell death of cardiomyocytes will be addressed. Here we will also review strategies to improve mitochondrial function and discuss their cardioprotective potential.
Asunto(s)
Cardiopatías/metabolismo , Mitocondrias Cardíacas/metabolismo , Dinámicas Mitocondriales , Miocitos Cardíacos/metabolismo , Transducción de Señal , Remodelación Ventricular , Animales , Metabolismo Energético , Fibrosis , Cardiopatías/patología , Cardiopatías/fisiopatología , Humanos , Mitocondrias Cardíacas/patología , Mitofagia , Contracción Miocárdica , Miocitos Cardíacos/patología , Estrés Oxidativo , Especies Reactivas de Oxígeno/metabolismoRESUMEN
UNLABELLED: In the heart, cardiac fibroblasts (CF) and cardiac myofibroblasts (CMF) are the main cells responsible for wound healing after cardiac insult. Exchange protein activated by cAMP (EPAC) is a downstream effector of cAMP, and it has been not completely studied on CF. Moreover, in CMF, which are the main cells responsible for cardiac healing, EPAC expression and function are unknown. We evaluated in both CF and CMF the effect of transforming growth factor ß1 (TGF-ß1) on EPAC-1 expression. We also studied the EPAC involvement on collagen synthesis, adhesion, migration and collagen gel contraction. METHOD: Rat neonatal CF and CMF were treated with TGF-ß1 at different times and concentrations. EPAC-1 protein levels and Rap1 activation were measured by western blot and pull down assay respectively. EPAC cellular functions were determined by adhesion, migration and collagen gel contraction assay; and collagen expression was determined by western blot. RESULTS: TGF-ß1 through Smad and JNK significantly reduced EPAC-1 expression in CF, while in CMF this cytokine increased EPAC-1 expression through ERK1/2, JNK, p38, AKT and Smad3. EPAC activation was able to induce higher Rap1-GTP levels in CMF than in CF. EPAC and PKA, both cAMP effectors, promoted CF and CMF adhesion on fibronectin, as well as CF migration; however, this effect was not observed in CMF. EPAC but not PKA activation mediated collagen gel contraction in CF, while in CMF both PKA and EPAC mediated collagen gel contraction. Finally, the EPAC and PKA activation reduced collagen synthesis in CF and CMF. CONCLUSION: TGF-ß1 differentially regulates the expression of EPAC in CF and CMF; and EPAC regulates differentially CF and CMF functions associated with cardiac remodeling.
Asunto(s)
Fibroblastos/efectos de los fármacos , Factores de Intercambio de Guanina Nucleótido/biosíntesis , Factores de Intercambio de Guanina Nucleótido/fisiología , Ventrículos Cardíacos/efectos de los fármacos , Factor de Crecimiento Transformador beta1/farmacología , Animales , Animales Recién Nacidos , Adhesión Celular/efectos de los fármacos , Adhesión Celular/fisiología , Diferenciación Celular/efectos de los fármacos , Diferenciación Celular/fisiología , Movimiento Celular/efectos de los fármacos , Movimiento Celular/fisiología , Células Cultivadas , Colágeno/biosíntesis , Fibroblastos/metabolismo , Ventrículos Cardíacos/citología , Ventrículos Cardíacos/metabolismo , Miofibroblastos/efectos de los fármacos , Miofibroblastos/metabolismo , Ratas , Ratas Sprague-Dawley , Remodelación Ventricular/fisiologíaRESUMEN
The gradual accumulation and inadequate renewal of senescent cells over time drive organismal aging. Senescent cells undergo altered gene expression and release inflammatory mediators collectively termed the senescence-associated secretory phenotype (SASP), which significantly contributes to a spectrum of age-related disorders, including cancer. In the context of carcinogenesis, the SASP produced by senescent cells has been implicated in the promotion of epithelial cancers, including oral squamous cell carcinoma (OSCC), the most common form of oral cancer. Senescent cells within the tumor microenvironment release factors that amplify the growth and invasiveness of neighboring cancer cells. Senotherapeutics, including senolytics and senomorphics, emerge as promising modalities to target senescent cells and their associated inflammatory factors, thereby opening novel avenues for augmenting the efficacy of cancer treatments. Here, we review the general aspects of cellular senescence, focusing on the relation between senescence-related inflammation with cancer development. We also analyze the available evidence linking cellular senescence with OSCC, highlighting possible clinical applications.
RESUMEN
UNLABELLED: Several clinical trials have shown the beneficial effects of statins in the prevention of coronary heart disease. Additionally, statins promote apoptosis in vascular smooth muscle cells, in renal tubular epithelial cells and also in a variety of cell lines; yet, the effects of statins on cardiac fibroblast and myofibroblast, primarily responsible for cardiac tissue healing are almost unknown. Here, we investigated the effects of simvastatin on cardiac fibroblast and myofibroblast viability and studied the molecular cell death mechanism triggered by simvastatin in both cell types. METHODS: Rat neonatal cardiac fibroblasts and myofibroblasts were treated with simvastatin (0.1-10µM) up to 72h. Cell viability and apoptosis were evaluated by trypan blue exclusion method and by flow cytometry, respectively. Caspase-3 activation and Rho protein levels and activity were also determined by Western blot and pull-down assay, respectively. RESULTS: Simvastatin induces caspase-dependent apoptosis of cardiac fibroblasts and myofibroblasts in a concentration- and time-dependent manner, with greater effects on fibroblasts than myofibroblasts. These effects were prevented by mevalonate, farnesylpyrophosphate and geranylgeranylpyrophosphate, but not squalene. These last results suggest that apoptosis was dependent on small GTPases of the Rho family rather than Ras. CONCLUSION: Simvastatin triggered apoptosis of cardiac fibroblasts and myofibroblasts by a mechanism independent of cholesterol synthesis, but dependent of isoprenilation of Rho protein. Additionally, cardiac fibroblasts were more susceptible to simvastatin-induced apoptosis than cardiac myofibroblasts. Thus simvastatin could avoid adverse cardiac remodeling leading to a less fibrotic repair of the damaged tissues.
Asunto(s)
Apoptosis/efectos de los fármacos , Fibroblastos/efectos de los fármacos , Corazón/efectos de los fármacos , Inhibidores de Hidroximetilglutaril-CoA Reductasas/farmacología , Miofibroblastos/efectos de los fármacos , Simvastatina/farmacología , Proteína de Unión al GTP rhoA/fisiología , Animales , Benzamidas/farmacología , Caspasas/fisiología , Supervivencia Celular/efectos de los fármacos , Células Cultivadas , Colesterol/biosíntesis , Fibroblastos/fisiología , Metionina/análogos & derivados , Metionina/farmacología , Miofibroblastos/fisiología , Ratas , Ratas Sprague-DawleyRESUMEN
Communication between cells is a foundational concept for understanding the physiology and pathology of biological systems. Paracrine/autocrine signaling, direct cell-to-cell interplay, and extracellular matrix interactions are three types of cell communication that regulate responses to different stimuli. In the heart, cardiomyocytes, fibroblasts, and endothelial cells interact to form the cardiac tissue. Under pathological conditions, such as myocardial infarction, humoral factors released by these cells may induce tissue damage or protection, depending on the type and concentration of molecules secreted. Cardiac remodeling is also mediated by the factors secreted by cardiomyocytes and fibroblasts that are involved in the extensive reciprocal interactions between these cells. Identifying the molecules and cellular signal pathways implicated in these processes will be crucial for creating effective tissue-preserving treatments during or after reperfusion. Numerous therapies to protect cardiac tissue from reperfusion-induced injury have been explored, and ample pre-clinical research has attempted to identify drugs or techniques to mitigate cardiac damage. However, despite great success in animal models, it has not been possible to completely translate these cardioprotective effects to human applications. This review provides a current summary of the principal molecules, pathways, and mechanisms underlying cardiomyocyte and cardiac fibroblast crosstalk during ischemia/reperfusion injury. We also discuss pre-clinical molecules proposed as treatments for myocardial infarction and provide a clinical perspective on these potential therapeutic agents.
RESUMEN
In the normal heart, cardiac fibroblasts (CFs) maintain extracellular matrix (ECM) homeostasis, whereas in pathological conditions, such as diabetes mellitus (DM), CFs converse into cardiac myofibroblasts (CMFs) and this CFs phenoconversion increase the synthesis and secretion of ECM proteins, promoting cardiac fibrosis and heart dysfunction. High glucose (HG) conditions increase TGF-ß1 expression and FoxO1 activity, whereas FoxO1 is crucial to CFs phenoconversion induced by TGF-ß1. In addition, FoxO1 increases CTGF expression, whereas CTGF plays an active role in the fibrotic process induced by hyperglycemia. However, the role of FoxO1 and CTGF in CFs phenoconversion induced by HG is not clear. In this study, we investigated the effects of FoxO1 pharmacological inhibition on CFs phenoconversion in both in vitro and ex vivo models of DM. Our results demonstrate that HG induces CFs phenoconversion and FoxO1 activation. Moreover, AS1842856, a pharmacological inhibitor of FoxO1 activity, prevents CFs phenoconversion and CTGF expression increase induced by HG, whereas these results were corroborated by FoxO1 silencing. Additionally, K252a, a pharmacological blocker of CTGF receptor, prevents HG-induced CFs phenoconversion, which was corroborated with CTGF expression knockdown. Furthermore, through CFs isolation from heart of diabetic rats, we showed that hyperglycemia induces FoxO1 activation, the increase of CTGF expression and CFs phenoconversion, whereas the FoxO1 activity inhibition reverses the effects induced by hyperglycemia on CFs. Altogether, our results demonstrate that FoxO1 and CTGF are necessary for CFs phenoconversion induced by HG and suggest that both proteins are likely to become a potential targeted drug for fibrotic response induced by hyperglycemic conditions.
Asunto(s)
Diferenciación Celular/efectos de los fármacos , Glucosa/farmacología , Miocardio/metabolismo , Miofibroblastos/metabolismo , Proteínas del Tejido Nervioso/metabolismo , Animales , Diferenciación Celular/genética , Proteínas del Tejido Nervioso/genética , Ratas , Ratas Sprague-DawleyRESUMEN
Cardiomyocyte loss is the main cause of myocardial dysfunction following an ischemia-reperfusion (IR) injury. Mitochondrial dysfunction and altered mitochondrial network dynamics play central roles in cardiomyocyte death. Proteasome inhibition is cardioprotective in the setting of IR; however, the mechanisms underlying this protection are not well-understood. Several proteins that regulate mitochondrial dynamics and energy metabolism, including Mitofusin-2 (Mfn2), are degraded by the proteasome. The aim of this study was to evaluate whether proteasome inhibition can protect cardiomyocytes from IR damage by maintaining Mfn2 levels and preserving mitochondrial network integrity. Using ex vivo Langendorff-perfused rat hearts and in vitro neonatal rat ventricular myocytes, we showed that the proteasome inhibitor MG132 reduced IR-induced cardiomyocyte death. Moreover, MG132 preserved mitochondrial mass, prevented mitochondrial network fragmentation, and abolished IR-induced reductions in Mfn2 levels in heart tissue and cultured cardiomyocytes. Interestingly, Mfn2 overexpression also prevented cardiomyocyte death. This effect was apparently specific to Mfn2, as overexpression of Miro1, another protein implicated in mitochondrial dynamics, did not confer the same protection. Our results suggest that proteasome inhibition protects cardiomyocytes from IR damage. This effect could be partly mediated by preservation of Mfn2 and therefore mitochondrial integrity.
Asunto(s)
GTP Fosfohidrolasas/metabolismo , Proteínas Mitocondriales/metabolismo , Infarto del Miocardio/tratamiento farmacológico , Daño por Reperfusión Miocárdica/prevención & control , Complejo de la Endopetidasa Proteasomal/metabolismo , Inhibidores de Proteasoma/farmacología , Animales , Animales Recién Nacidos , Apoptosis/efectos de los fármacos , Células Cultivadas , Modelos Animales de Enfermedad , Humanos , Preparación de Corazón Aislado , Masculino , Mitocondrias/efectos de los fármacos , Infarto del Miocardio/complicaciones , Daño por Reperfusión Miocárdica/etiología , Daño por Reperfusión Miocárdica/patología , Miocitos Cardíacos/citología , Miocitos Cardíacos/efectos de los fármacos , Miocitos Cardíacos/patología , Cultivo Primario de Células , Inhibidores de Proteasoma/uso terapéutico , Ratas , Proteínas de Unión al GTP rho/metabolismoRESUMEN
Cardiac fibroblasts are the major non-myocyte cell constituent in the myocardium, and they are involved in heart remodeling. Angiotensin II type 1 receptor (AT1R) mediates the established actions of angiotensin II (Ang II), and changes in its expression have been reported in cardiac fibroblasts after myocardial infarction. However, the AT1R-dependent signaling pathways involved in cardiac fibroblast death remain unknown. Using adenovirus, we ectopically expressed AT1R in cultured neonatal rat cardiac fibroblasts and investigated the role of the phospholipase (PLC)/protein kinase C (PKC) pathway on Ang II-dependent death. Ang II induced cardiac fibroblast death characterized by an early loss of mitochondrial membrane potential, increased Bax/Bcl-2 ratio, caspase-3 activation, and DNA fragmentation. All these effects were prevented by the AT1R antagonist losartan, PLC inhibitor U73122, and PKC inhibitor Gö6976. We conclude that Ang II stimulates the intrinsic apoptotic pathway in cultured cardiac fibroblasts by the AT1R/PLC/PKC signaling pathway.
Asunto(s)
Angiotensina II/fisiología , Apoptosis , Fibroblastos/efectos de los fármacos , Proteína Quinasa C/fisiología , Receptor de Angiotensina Tipo 1/biosíntesis , Fosfolipasas de Tipo C/fisiología , Angiotensina II/farmacología , Bloqueadores del Receptor Tipo 1 de Angiotensina II/farmacología , Animales , Animales Recién Nacidos , Carbazoles/farmacología , Células Cultivadas , Estrenos/farmacología , Fibroblastos/citología , Fibroblastos/metabolismo , Expresión Génica , Losartán/farmacología , Proteína Quinasa C/antagonistas & inhibidores , Pirrolidinonas/farmacología , Ratas , Ratas Sprague-Dawley , Receptor de Angiotensina Tipo 1/genética , Transducción de Señal , Fosfolipasas de Tipo C/antagonistas & inhibidoresRESUMEN
Statins reduce the isoprenoids farnesyl and geranylgeranyl pyrophosphate, essential intermediates, which control a diversity of cellular events such as cytoskeleton integrity, adhesion, migration and viability. Cardiac fibroblasts are the major non-myocyte cell constituent in the normal heart, and play a key role in the maintenance of extracellular matrix. The effects of simvastatin on cardiac fibroblast processes previously mentioned remain unknown. Our aims were to investigate the effects of simvastatin on cytoskeleton structure and focal adhesion complex assembly and their relationships with cell adhesion, migration and viability in cultured cardiac fibroblasts. To this end, cells were treated with simvastatin for 24 h and changes in actin cytoskeleton, levels of vimentin and paxillin as well as their subcellular localization were analyzed by Western blot and immunocytochemistry, respectively. Cell adhesion to plastic or collagen coated dishes, migration in Transwell chambers, and cell viability were analyzed after simvastatin treatment. Our results show that simvastatin disrupts actin cytoskeleton and focal adhesion complex evaluated by phalloidin stain and immunocytochemistry for paxillin and vinculin. All these effects occurred by a cholesterol synthesis-independent mechanism. Simvastatin decreased cell adhesion, migration and viability in a concentration-dependent manner. Finally, simvastatin decreased angiotensin II-induced phospho-paxillin levels and cell adhesion. We concluded that simvastatin disrupts cytoskeleton integrity and focal adhesion complex assembly in cultured cardiac fibroblasts by a cholesterol-independent mechanism and consequently decreases cell migration, adhesion and viability.
Asunto(s)
Inhibidores de Hidroximetilglutaril-CoA Reductasas/efectos adversos , Miofibroblastos/efectos de los fármacos , Simvastatina/efectos adversos , Animales , Western Blotting , Adhesión Celular/efectos de los fármacos , Movimiento Celular/efectos de los fármacos , Supervivencia Celular/efectos de los fármacos , Células Cultivadas , Citoesqueleto/efectos de los fármacos , Miofibroblastos/fisiología , Paxillin/efectos de los fármacos , Ratas , Ratas Sprague-Dawley , Simvastatina/antagonistas & inhibidores , Terpenos/farmacología , Vinculina/efectos de los fármacosRESUMEN
AIMS: Insulin-like growth factor 1 (IGF-1) is known to exert cardioprotective actions. However, it remains unknown if autophagy, a major adaptive response to nutritional stress, contributes to IGF-1-mediated cardioprotection. METHODS AND RESULTS: We subjected cultured neonatal rat cardiomyocytes, as well as live mice, to nutritional stress and assessed cell death and autophagic rates. Nutritional stress induced by serum/glucose deprivation strongly induced autophagy and cell death, and both responses were inhibited by IGF-1. The Akt/mammalian target of rapamycin (mTOR) pathway mediated the effects of IGF-1 upon autophagy. Importantly, starvation also decreased intracellular ATP levels and oxygen consumption leading to AMP-activated protein kinase (AMPK) activation; IGF-1 increased mitochondrial Ca(2+) uptake and mitochondrial respiration in nutrient-starved cells. IGF-1 also rescued ATP levels, reduced AMPK phosphorylation and increased p70(S6K) phosphorylation, which indicates that in addition to Akt/mTOR, IGF-1 inhibits autophagy by the AMPK/mTOR axis. In mice harbouring a liver-specific igf1 deletion, which dramatically reduces IGF-1 plasma levels, AMPK activity and autophagy were increased, and significant heart weight loss was observed in comparison with wild-type starved animals, revealing the importance of IGF-1 in maintaining cardiac adaptability to nutritional insults in vivo. CONCLUSION: Our data support the cardioprotective actions of IGF-1, which, by rescuing the mitochondrial metabolism and the energetic state of cells, reduces cell death and controls the potentially harmful autophagic response to nutritional challenges. IGF-1, therefore, may prove beneficial to mitigate damage induced by excessive nutrient-related stress, including ischaemic disease in multiple tissues.
Asunto(s)
Autofagia/efectos de los fármacos , Metabolismo Energético/efectos de los fármacos , Factor I del Crecimiento Similar a la Insulina/farmacología , Miocitos Cardíacos/efectos de los fármacos , Proteínas Quinasas Activadas por AMP/fisiología , Adenosina Trifosfato/metabolismo , Animales , Calcio/metabolismo , Células Cultivadas , Ratones , Miocitos Cardíacos/metabolismo , Ratas , Ratas Sprague-Dawley , Transducción de Señal/fisiología , Serina-Treonina Quinasas TOR/fisiologíaRESUMEN
Históricamente, la apoptosis y la necrosis han sido consideradas como las dos formas fundamentales de muerte celular. Sin embargo, evidencias recientes sugieren que la muerte celular programada no está confinada sólo a la apoptosis sino que las células disponen de distintos mecanismos de autodestrucción, entre los que se cuenta la autofagia. Esta última se define como un proceso dinámico y programado que procede con el secuestro de proteínas citoplasmáticas y organelos enteros dentro de vacuolas de doble membrana, que se contactan y se fusionan con los lisosomas, formando los autolisosomas. Los elementos capturados en las vacuolas son degradados por proteasas lisosomales y removidos de la célula por exocitosis. La autofagia se describió inicialmente como un proceso fisiológico clave para la sobrevida celular en respuesta al estrés derivado de la privación de nutrientes. Además, la autofagia también se ha observado en algunas patologías cardiovasculares, especialmente aquellas asociadas a procesos de isquemia/reperfusión. En esta revisión se sintetiza el conocimiento actual de la autofagia, sus implicancias y proyecciones en el área cardiovascular.
Asunto(s)
Humanos , Apoptosis , Miocitos Cardíacos/fisiología , Necrosis , Vacuolas/fisiologíaRESUMEN
El factor de crecimiento análogo a insulina tipo 1 (IGF-1) es un péptido relacionado estructural y funcionalmente con insulina que posee efectos mitogénicos y citoprotectores. Sus efectos biológicos dependen de la activación del receptor de IGF- 1 (IGF-1R), perteneciente a la familia de receptores con actividad tirosina kinasa intrínseca y que se localiza en la superficie celular. IGF-1 es el principal mediador fisiológico de la hormona del crecimiento y dado que su gen se expresa en múltiplestejidos, este factor es clave en la comunicación endocrina, paracrina y autocrina. Recientes evidencias muestran que IGF- 1 ejerce variadas acciones pleiotrópicas en el sistema cardiovascular, destacándose sus efectos en la hipertrofia, muerte y regeneración celular. En el corazón, IGF-1 promueve su crecimiento, mejora su contractibilidad, facilita el metabolismode la glucosa, disminuye el nivel de insulina circulante, aumenta la sensibilidad a esta hormona, estabiliza el perfil lipídico y estimula la regeneración del músculo cardíaco. Evidencias clínicas y experimentales han mostrado que el deterioro de la función cardíaca se asocia a bajos niveles circulantes de IGF-1. Alteraciones tanto en los niveles de IGF-1 como en su sistema transduccional se consideran factores de riesgo para el desarrollo de distintas patologías cardíacas. Todosestos antecedentes destacan el papel del IGF-1 en cardioprotección y su potencialidad para el tratamiento de diversas patologías cardiovasculares. Sin embargo, los mecanismos moleculares implicados en estos efectos prácticamente se desconocen. En esta revisión, junto con entregar antecedentes actualizados y críticos de las acciones cardiovasculares del IGF-1, se proyectan sus aplicaciones terapéuticas.