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Although our previous studies have established the crucial role of RP105 in myocardial ischemia/reperfusion injury (MI/RI), its involvement in regulating oxidative stress induced by MI/RI remains unclear. To investigate this, we conducted experiments using a rat model of ischemia/reperfusion (I/R) injury. Adenovirus carrying RP105 was injected apically at multiple points, and after 72 h, the left anterior descending coronary artery was ligated for 30 min followed by 2 h of reperfusion. In vitro experiments were performed on H9C2 cells, which were transfected with recombinant adenoviral vectors for 48 h, subjected to 4 h of hypoxia, and then reoxygenated for 2 h. We measured oxidative stress markers, including superoxide dismutase (SOD) and glutathione peroxidase (GSH-Px) activities, as well as malondialdehyde (MDA) concentration, using a microplate reader. The fluorescence intensity of reactive oxygen species (ROS) in myocardial tissue was measured using a DHE probe. We also investigated the upstream and downstream components of the signal transducer and activator of transcription 3 (STAT3). Upregulation of RP105 increased SOD and GSH-Px activities, reduced MDA concentration, and inhibited ROS production in response to I/R injury in vivo and hypoxia reoxygenation (H/R) stimulation in vitro. The overexpression of RP105 led to a decrease in the myocardial enzyme LDH in serum and cell culture supernatant, as well as a reduction in infarct size. Additionally, left ventricular fraction (LVEF) and fractional shortening (LVFS) were improved in the RP105 overexpression group compared to the control. Upregulation of RP105 promoted the expression of Lyn and Syk and further activated STAT phosphorylation, which was blocked by PP2 (a Lyn inhibitor). Our findings suggest that RP105 can inhibit MI/RI-induced oxidative stress by activating STAT3 via the Lyn/Syk signaling pathway.
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Daño por Reperfusión Miocárdica , Miocardio , Estrés Oxidativo , Factor de Transcripción STAT3 , Transducción de Señal , Quinasa Syk , Animales , Estrés Oxidativo/fisiología , Factor de Transcripción STAT3/metabolismo , Transducción de Señal/fisiología , Daño por Reperfusión Miocárdica/metabolismo , Daño por Reperfusión Miocárdica/prevención & control , Daño por Reperfusión Miocárdica/patología , Ratas , Miocardio/metabolismo , Miocardio/patología , Quinasa Syk/metabolismo , Familia-src Quinasas/metabolismo , Masculino , Línea Celular , Ratas Sprague-Dawley , Especies Reactivas de Oxígeno/metabolismoRESUMEN
Cell proliferation and differentiation are the basic physiological activities of cells. Mistakes in these processes may affect cell survival, or cause cell cycle dysregulation, such as tumorigenesis, birth defects and degenerative diseases. In recent years, it has been found that histone methyltransferase DOT1L is the only H3 lysine 79 methyltransferase, which plays an important role in the process of cell fate determination through monomethylation, dimethylation and trimethylation of H3K79. DOT1L has a pro-proliferative effect in leukemia cells; however, loss of heart-specific DOT1L leads to increased proliferation of cardiac tissue. Additionally, DOT1L has carcinogenic or tumor suppressive effects in different neoplasms. At present, some DOT1L inhibitors for the treatment of MLL-driven leukemia have achieved promising results in clinical trials, but completely blocking DOT1L will also bring some side effects. Thus, this uncertainty suggests that DOT1L has a unique function in cell physiology. In this review, we summarize the primary findings of DOT1L in regulating cell proliferation and differentiation. Correlations between DOT1L and cell fate specification might suggest DOT1L as a therapeutic target for diseases.
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Histonas , Leucemia , Humanos , Proliferación Celular , Diferenciación Celular , Ciclo Celular , N-Metiltransferasa de Histona-Lisina/metabolismoRESUMEN
As a transcriptional activator widely expressed in various tissues, nuclear factor of activated T cells (NFAT) is involved in the regulation of the immune system, the development of the heart and brain systems, and classically mediating pathological processes such as cardiac hypertrophy. Oxidative stress is an imbalance of intracellular redox status, characterized by excessive generation of reactive oxygen species, accompanied by mitochondrial dysfunction, calcium overload, and subsequent lipid peroxidation, inflammation, and apoptosis. Oxidative stress occurs during various pathological processes, such as chronic hypoxia, vascular smooth muscle cell phenotype switching, ischemia-reperfusion, and cardiac remodeling. Calcium overload leads to an increase in intracellular calcium concentration, while NFAT can be activated through calcium-calcineurin, which is also the main regulatory mode of NFAT factors. This review focuses on the effects of NFAT transcription factors on reactive oxygen species production, calcium overload, mitochondrial dysfunction, redox reactions, lipid peroxidation, inflammation, and apoptosis in response to oxidative stress. We hope to provide a reference for the functions and characteristics of NFAT involved in various stages of oxidative stress as well as related potential targets.
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Calcio , Estrés Oxidativo , Humanos , Especies Reactivas de Oxígeno/farmacología , Calcio/metabolismo , Calcio/farmacología , Factores de Transcripción NFATC/metabolismo , Factores de Transcripción NFATC/farmacología , Oxidación-Reducción , InflamaciónRESUMEN
Immune diseases are caused by the imbalance of immune regulation. This imbalance is regulated by many factors, both negative and positive. Leukocyte immunoglobulin-like receptor B4 (LILRB4) is a member of leukocyte immunoglobulin-like receptors (LILRs). LILRs are expressed constitutively on the surface of multiple immune cells which associate with membrane adaptors to signal through multi- ple cytoplasmic immunoreceptor tyrosine-based inhibitory motifs (ITIMs) or immunoreceptor tyro-sine-based activation motifs (ITAMs). Through ITIM, LILRB4 could recruit the src homology domain type-2-containing tyrosine phosphatase 1 or 2 (SHP-1 or SHP-2) into the cell membrane. In addition, many factors can induce the expression of LILRB4, such as vitamin D, interferon and so on. Studies have demonstrated that LILRB4 had a negative regulatory role in various of immune diseases. The present review intends to expound the structure and function of LILRB4, as well as its regulators and receptors in the immune cells, so as to provide a theoretical basis for immune disease therapy.
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Leucocyte immunoglobulin-like receptors subfamily B (LILRB) belongs to the type I transmembrane glycoproteins, which is the immunosuppressive receptor. LILRBs are widely expressed in bone marrow cells, hematopoietic stem cells, nerve cells and other body cells. Studies have found that LILRBs receptor can bind to a variety of ligands and has a variety of biological functions such as regulating inflammatory response, immune tolerance and cell differentiation. Inflammatory reaction plays a vital role in resisting microorganisms. The function of inhibitory immune receptors can recognize the signs of infection and promote the function of anti-microbial effect. The inflammatory response must be strictly regulated to prevent excessive inflammation and tissue damage. Therefore, it is of general interest to understand the role of LILRBs in the inflammatory response. Because they can inhibit the anti-microbial response of neutrophils, some human pathogens use these receptors to escape immunity. This article reviews the biological role of LILRBs in the inflammatory response. We focus on the known ligands of LILRBs, their different roles after binding with ligands, and how these receptors help to form neutrophil responses during infection. Recent studies have shown that LILRBs recruit phosphatases through intracellular tyrosine-based immunoreceptor inhibitory motifs to negatively regulate immune activation, thereby transmitting inflammation-related signals, suggesting that LILRBs may be an ideal target for the treatment of inflammatory diseases. Here, we describe in detail the regulation of LILRBs on the inflammatory response, its signal transduction mode in inflammation, and the progress in the treatment of inflammatory diseases, providing a reference for further research.
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Inflamación , Receptores Inmunológicos , Humanos , Receptores Inmunológicos/genética , Transducción de Señal , Neutrófilos/metabolismo , LigandosRESUMEN
BACKGROUND: Renal fibrosis is the common pathway in chronic kidney diseases progression to end-stage renal disease, but to date, no clinical drug for its treatment is approved. It has been demonstrated that the inhibitor of proto-oncogene Ras, farnesylthiosalicylic acid (FTS), shows therapeutic potential for renal fibrosis, but its application was hindered by the water-insolubility and low bioavailability. Hence, in this study, we improved these properties of FTS by encapsulating it into bovine serum albumin nanoparticles (AN-FTS) and tested its therapeutic effect in renal fibrosis. METHODS: AN-FTS was developed using a classic emulsification-solvent ultrasonication. The pharmacokinetics of DiD-loaded albumin nanoparticle were investigated in SD rats. The biodistribution and therapeutic efficacy of AN-FTS was assessed in a mouse model of renal fibrosis induced by unilateral ureteral obstruction (UUO). RESULTS: AN-FTS showed a uniform spherical shape with the size of 100.6 ± 1.12 nm and PDI < 0.25. In vitro, AN-FTS displayed stronger inhibitory effects on the activation of renal fibroblasts cells NRK-49F than free FTS. In vivo, AN-FTS showed significantly higher peak concentration and area under the concentration-time curve. After intravenous administration to UUO-induced renal fibrosis mice, AN-FTS accumulated preferentially in the fibrotic kidney, and alleviated renal fibrosis and inflammation significantly more than the free drug. Mechanistically, the improved anti-fibrosis effect of AN-FTS was associated with greater inhibition in renal epithelial-to-mesenchymal transformation process via Ras/Raf1/p38 signaling pathway. CONCLUSION: The study reveals that AN-FTS is capable of delivering FTS to fibrotic kidney and showed superior therapeutic efficacy for renal fibrosis.
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Nanopartículas , Transducción de Señal , Albúminas , Animales , Farnesol/análogos & derivados , Fibrosis , Ratones , Proteínas Proto-Oncogénicas c-raf , Ratas , Ratas Sprague-Dawley , Salicilatos , Distribución TisularRESUMEN
BACKGROUND AND PURPOSE: Cholesterol is an essential lipid and its homeostasis is a major factor for many diseases, such as hyperlipidemia, atherosclerosis, diabetes, and obesity. Sodium-glucose cotransporter 2 (SGLT2) inhibitor canagliflozin (Cana) is a new kind of hypoglycemic agent, which decreases urinary glucose reabsorption and reduces hyperglycemia. Cana has been shown to regulate serum lipid, decrease serum triglyceride and increase serum high-density lipoprotein-cholesterol (HDL-C), and improve cardiovascular outcomes. But evidence of how Cana impacted the cholesterol metabolism remains elusive. METHODS: We treated Cana on mice with chow diet or western diet and then detected cholesterol metabolism in the liver and intestine. To explore the mechanism, we also treated hepG2 cells and Caco2 cells with different concentrations of Cana. RESULTS: In this study, we showed that Cana facilitated hepatic and intestinal cholesterol efflux. Mechanically, Cana via activating adenosine monophosphate-activated protein kinase (AMPK) increased the expression of ATP-binding cassette (ABC) transporters ABCG5 and ABCG8 in liver and intestine, increased biliary and fecal cholesterol excretion. CONCLUSION: This research confirms that Cana regulates cholesterol efflux and improves blood and hepatic lipid; this may be a partial reason for improving cardiovascular disease.
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Proteínas Quinasas Activadas por AMP/metabolismo , Transportadoras de Casetes de Unión a ATP/metabolismo , Canagliflozina/metabolismo , Colesterol/metabolismo , Animales , Células Cultivadas , Humanos , Masculino , Ratones , Ratones Endogámicos C57BLRESUMEN
Activating beige adipocytes in white adipose tissue (WAT) to increase energy expenditure is a promising strategy to combat obesity. We identified that mesencephalic astrocyte-derived neurotrophic factor (Manf) is a feeding-induced hepatokine. Liver-specific Manf overexpression protected mice against high-fat diet-induced obesity and promoted browning of inguinal subcutaneous WAT (iWAT). Manf overexpression in liver was also associated with decreased adipose inflammation and improved insulin sensitivity and hepatic steatosis. Mechanistically, Manf could directly promote browning of white adipocytes via the p38 MAPK pathway. Blockade of p38 MAPK abolished Manf-induced browning. Consistently, liver-specific Manf knockout mice showed impaired iWAT browning and exacerbated diet-induced obesity, insulin resistance, and hepatic steatosis. Recombinant Manf reduced obesity and improved insulin resistance in both diet-induced and genetic obese mouse models. Finally, we showed that circulating Manf level was positively correlated with BMI in humans. This study reveals the crucial role of Manf in regulating thermogenesis in adipose tissue, representing a potential therapeutic target for obesity and related metabolic disorders.
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Adipocitos/metabolismo , Tejido Adiposo Pardo/metabolismo , Tejido Adiposo Blanco/metabolismo , Hígado/metabolismo , Factores de Crecimiento Nervioso/metabolismo , Obesidad/metabolismo , Proteínas Quinasas p38 Activadas por Mitógenos/metabolismo , Animales , Dieta Alta en Grasa/efectos adversos , Metabolismo Energético/fisiología , Femenino , Humanos , Resistencia a la Insulina/fisiología , Masculino , Enfermedades Metabólicas/metabolismo , Ratones , Ratones Endogámicos C57BL , Ratones Noqueados , Ratones Obesos/metabolismo , Persona de Mediana Edad , Termogénesis/fisiologíaRESUMEN
OBJECTIVE: Previous studies have established that deficiency in Nucleotide-binding and oligomerization domain (NOD)-like receptor family pyrin domain containing 6 (Nlrp6) changes the configuration of the gut microbiota, which leads to hepatic steatosis. Here, we aimed to determine the hepatic function of Nlrp6 in lipid metabolism and inflammation and its role in the development of non-alcoholic steatohepatitis (NASH). METHODS: Nlrp6Loxp/Loxp and hepatocyte-specific Nlrp6-knockout mice were fed a high-fat diet (HFD) or methionine-choline deficient (MCD) diet to induce fatty liver or steatohepatitis, respectively. Primary hepatocytes were isolated to further explore the underlying mechanisms in vitro. In addition, we used adenovirus to overexpress Nlrp6 in ob/ob mice to demonstrate its role in NASH. RESULTS: Hepatic Nlrp6 expression was downregulated in NASH patients and in obese mice. Hepatocyte-specific Nlrp6 deficiency promoted HFD- or MCD diet-induced lipid accumulation and inflammation, whereas Nlrp6 overexpression in ob/ob mice had beneficial effects. In vitro studies demonstrated that knockdown of Nlrp6 aggravated hepatic steatosis and inflammation in hepatocytes, but its overexpression markedly attenuated these abnormalities. Moreover, both in vitro and in vivo study demonstrated that Nlrp6 inhibited Cd36-mediated lipid uptake. Nlrp6 deficiency-enhanced fatty acid uptake was blocked by a Cd36 inhibitor in hepatocytes. Nlrp6 ablation increased the expression of proinflammatory cytokines, likely as a result of increased NF-κB phosphorylation and activation. Mechanistically, Nlrp6 promoted the degradation of transforming growth factor-ß-activated kinase 1 (TAK1)-binding protein 2/3 (TAB2/3) via a lysosomal-dependent pathway, which suppressed NF-κB activation. CONCLUSIONS: Nlrp6 may play a key role in the pathological process of NASH by inhibiting Cd36 and NF-κB pathways. It may be a potential therapeutic target for NASH.
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Deficiencia de Colina , Enfermedad del Hígado Graso no Alcohólico , Animales , Modelos Animales de Enfermedad , Hepatocitos , Humanos , Péptidos y Proteínas de Señalización Intracelular , Hígado , Metionina , Ratones , Ratones Endogámicos C57BL , Ratones Noqueados , Enfermedad del Hígado Graso no Alcohólico/genética , Receptores de Superficie CelularRESUMEN
Alcoholic fatty liver disease (AFLD) is induced by alcohol consumption and may progress to more severe liver diseases such as alcoholic steatohepatitis, fibrosis and cirrhosis, and even hepatocellular carcinoma. Mesencephalic astrocyte-derived neurotrophic factor (MANF) participates in maintaining lipid homeostasis. However, the role of MANF in the pathogenesis of AFLD remains unclear. We established an AFLD mouse model following the US National Institute on Alcohol Abuse and Alcoholism procedure. Both mRNA and protein levels of MANF were significantly increased in the chronic binge alcohol feeding model. Liver-specific knockout of MANF aggravated hepatic lipid accumulation. Similarly, liver-specific overexpression of MANF alleviated AFLD in mouse livers. MANF affected hepatic lipid metabolism by modulating autophagy. The levels of LC3-II and Atg5-Atg12 were decreased in mouse livers with MANF liver-specific knockout and increased with MANF liver-specific overexpression. Furthermore, MANF changed the phosphorylation of Stat3 and its nuclear localization. MANF may have a protective role in the development of AFLD.
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Autofagia , Hígado Graso Alcohólico/metabolismo , Factores de Crecimiento Nervioso/metabolismo , Factor de Transcripción STAT3/metabolismo , Animales , Autofagia/efectos de los fármacos , Consumo Excesivo de Bebidas Alcohólicas , Etanol/farmacología , Hígado/efectos de los fármacos , Hígado/metabolismo , Masculino , Ratones , Ratones Endogámicos C57BL , Factores de Crecimiento Nervioso/deficiencia , FosforilaciónRESUMEN
The enzyme 5-lipoxygenase (5-LO) converts arachidonic acid to leukotrienes, which mediate inflammation. The enzyme is known to contribute to organ fibrosis, but how it contributes to renal fibrosis is unclear. Here, we reported that fibrotic kidneys expressed high levels of 5-LO, and deleting the 5-LO gene mitigated renal fibrosis in mice subjected to unilateral ureteral obstruction (UUO), based on assays of collagen deposition, injury and inflammation. Mechanistically, the exogenous leukotrienes B4 and C4, the downstream products of 5-LO, could induce the epithelial-mesenchymal transition (EMT) in kidney epithelial cell cultures, based on assays of E-cadherin, vimentin and snail expression. Studies in UUO mice confirmed that 5-LO deletion inhibited the EMT in the obstructed kidney. More importantly, 5-LO inhibitor zileuton loaded in CREKA-Lip, which could target to fibrotic kidney, markedly attenuated UUO-induced renal fibrosis and injury by inhibiting the EMT in the obstructed kidney. Our results suggested that 5-LO activity may contribute to renal fibrosis by promoting renal EMT, implying that the enzyme may be a useful therapeutic target.
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Proteínas Activadoras de la 5-Lipooxigenasa/metabolismo , Transición Epitelial-Mesenquimal/fisiología , Enfermedades Renales/metabolismo , Transducción de Señal/fisiología , Inhibidores de Proteína Activante de 5-Lipoxigenasa/farmacología , Proteínas Activadoras de la 5-Lipooxigenasa/genética , Animales , Células Cultivadas , Femenino , Fibrosis , Humanos , Enfermedades Renales/genética , Masculino , Ratones , Ratones Endogámicos C57BL , Ratones NoqueadosRESUMEN
Sirtuin 6 (Sirt6), a member of the Sirtuin family, has important roles in maintaining glucose and lipid metabolism. Our previous studies demonstrated that the deletion of Sirt6 in pro-opiomelanocortin (POMC)-expressing cells by the loxP-Cre system resulted in severe obesity and hepatic steatosis. However, whether overexpression of Sirt6 in hypothalamic POMC neurons could ameliorate diet-induced obesity is still unknown. Thus, we generated mice specifically overexpressing Sirt6 in hypothalamic POMC neurons (PSOE) by stereotaxic injection of Cre-dependent adeno-associated viruses into the arcuate nucleus of Pomc-Cre mice. PSOE mice showed increased adiposity and decreased energy expenditure. Furthermore, thermogenesis of BAT and lipolysis of WAT were both impaired, caused by reduced sympathetic nerve innervation and activity in adipose tissues. Mechanistically, Sirt6 overexpression decreasing STAT3 acetylation, thus lowering POMC expression in the hypothalamus underlined the observed phenotypes in PSOE mice. These results demonstrate that Sirt6 overexpression specifically in the hypothalamic POMC neurons exacerbates diet-induced obesity and metabolic disorders via the hypothalamus-adipose axis.
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Hipotálamo/metabolismo , Neuronas/metabolismo , Obesidad/etiología , Proopiomelanocortina/metabolismo , Sirtuinas/metabolismo , Tejido Adiposo/metabolismo , Animales , Núcleo Arqueado del Hipotálamo/metabolismo , Metabolismo Energético/fisiología , Leptina/metabolismo , Ratones Endogámicos C57BL , Obesidad/metabolismo , Proopiomelanocortina/genéticaRESUMEN
BACKGROUND & AIMS: Cholesterol gallstone disease (CGD) is a common gastrointestinal disease. Liraglutide, an analogue of glucagon-like peptide 1, has been approved to treat type 2 diabetes. Clinical studies have suggested a potential role of liraglutide in CGD. METHODS: Mice were subcutaneously injected with liraglutide, then fed a lithogenic diet. Bile duct cannulation was performed to collect bile output in mice. Intestinal-specific ablation or pharmacological inhibition of farnesoid X receptor (FXR) was used to study its functions in CGD. RESULTS: Liraglutide could protect mice against CGD. Liraglutide treatment increased the biliary concentration of cholesterol, phospholipids and bile acids and thereby decreased the cholesterol saturation index. The resistance to CGD conferred by liraglutide is likely a result of increased bile acid synthesis and efficient bile acid transport. The expression of a key bile acid synthetic enzyme, Cyp7a1, was significantly increased in liraglutide-treated mice. The increased expression of Cyp7a1 resulted from a relieved suppression signal of Fgf15 from the ileum. Mechanistically, liraglutide treatment altered bile acid composition and suppressed FXR activity in the ileum. Genetic ablation or pharmacological inhibition of FXR in the intestine protected mice against CGD. More importantly, intestinal FXR was required for liraglutide-mediated regulation of hepatic expression of Cyp7a1. CONCLUSION: Liraglutide improved CGD by increasing bile acid secretion and decreasing cholesterol saturation index. Liraglutide attenuates the negative feedback inhibition of bile acids through inhibiting intestinal FXR activity. Our results suggest that liraglutide may represent a novel way for treating or preventing cholesterol gallstones in individuals with high risk of CGD.
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Colesterol/metabolismo , Cálculos Biliares/prevención & control , Mucosa Intestinal/metabolismo , Liraglutida/farmacología , Receptores Citoplasmáticos y Nucleares/metabolismo , Animales , Ácidos y Sales Biliares/biosíntesis , Colesterol 7-alfa-Hidroxilasa/biosíntesis , Colesterol 7-alfa-Hidroxilasa/metabolismo , Dieta , Inducción Enzimática , Factores de Crecimiento de Fibroblastos/metabolismo , Cálculos Biliares/metabolismo , Masculino , Ratones , Ratones Endogámicos C57BL , Microsomas Hepáticos/enzimología , Transducción de SeñalRESUMEN
Renal fibrosis is the final manifestation of various chronic kidney diseases. Interstitial myofibroblasts, which are reported to highly express integrin αvß3, are the effector cells in renal fibrogenesis. Since current therapies do not efficiently target these cells, there is no effective therapeutic method for preventing or mitigating the disease. Here, we modified sterically stable PEGylated liposomes with the pentapeptide cRGDfC (RGD-Lip), which has a high affinity for αvß3, to specifically deliver drug to renal interstitial myofibroblasts. Our results showed that attaching cRGDfC to liposomes significantly increased their uptake by activated renal fibroblasts NRK-49F cells, and this effect was greatly abolished by adding excess-free cRGDfC or a knockdown of αvß3. Systemic administration of RGD-Lip gave rise to significant accumulation in a fibrotic kidney, which is ascribed to the specific recognition with integrin αvß3 on interstitial myofibroblasts. When loaded with celastrol, RGD-guided liposomes dramatically depressed the proliferation and activation of NRK-49F cells in vitro. Additionally, celastrol-loaded RGD-Lip markedly attenuated renal fibrosis, injury, and inflammation induced by unilateral ureteral obstruction (UUO) in mice, without inducing significant systemic toxicity. Thus, this liposomal system shows great promise for delivering therapeutic agents to interstitial myofibroblasts for renal fibrosis treatment with minimal side effects.
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Fibrosis/metabolismo , Integrina alfaVbeta3/metabolismo , Riñón/metabolismo , Miofibroblastos/metabolismo , Animales , Línea Celular , Células Epiteliales/metabolismo , Fibroblastos/metabolismo , Masculino , Ratones , Ratones Endogámicos C57BL , Células RAW 264.7 , Ratas , Insuficiencia Renal Crónica/metabolismo , Transducción de Señal/fisiología , Factor de Crecimiento Transformador beta1/metabolismo , Obstrucción Ureteral/metabolismoRESUMEN
BACKGROUNDS AND AIMS: Activation of hepatic stellate cells (HSCs) is a central driver of fibrosis. This study aimed to elucidate the role of the deacetylase sirtuin 6 (Sirt6) in HSC activation and liver fibrosis. APPROACH AND RESULTS: Gain-of-function and loss-of-function models were used to study the function of Sirt6 in HSC activation. Mass spectrometry was used to determine the specific acetylation site. The lecithin retinol acyltransferase-driven cyclization recombination recombinase construct (CreERT2) mouse line was created to generate HSC-specific conditional Sirt6-knockout mice (Sirt6â³HSC ). We found that Sirt6 is most abundantly expressed in HSCs as compared with other liver cell types. The expression of Sirt6 was decreased in activated HSCs and fibrotic livers of mice and humans. Sirt6 knockdown and Sirt6 overexpression increased and decreased fibrogenic gene expression, respectively, in HSCs. Mechanistically, Sirt6 inhibited the phosphorylation and nuclear localization of mothers against decapentaplegic homolog (Smad) 2. Further study demonstrated that Sirt6 could directly interact with Smad2, deacetylate Smad2, and decrease the transcription of transforming growth factor ß/Smad2 signaling. Mass spectrometry revealed that Sirt6 deacetylated conserved lysine 54 on Smad2. Mutation of lysine 54 to Arginine in Smad2 abolished the regulatory effect of Sirt6. In vivo, specific ablation of Sirt6 in HSCs exacerbated hepatocyte injury and cholestasis-induced liver fibrosis in mice. With targeted delivery of the Sirt6 agonist MDL-800, its concentration was 9.28-fold higher in HSCs as compared with other liver cells and alleviated hepatic fibrosis. CONCLUSIONS: Sirt6 plays a key role in HSC activation and liver fibrosis by deacetylating the profibrogenic transcription factor Smad2. Sirt6 may be a potential therapeutic target for liver fibrosis.
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Células Estrelladas Hepáticas/metabolismo , Cirrosis Hepática/metabolismo , Sirtuinas/metabolismo , Proteína Smad2/metabolismo , Animales , Inmunoprecipitación de Cromatina , Técnica del Anticuerpo Fluorescente , Humanos , Cirrosis Hepática/etiología , Ratones , Ratones Endogámicos C57BL , Ratones NoqueadosRESUMEN
Liver fibrosis is a common outcome of most chronic liver diseases, but there is no clinically approved drug for its treatment. Previous studies have reported the potential of SB431542 as an inhibitor of TGF-ß signaling in the treatment of liver fibrosis, but it shows poor water solubility and low bioavailability. Here, we improve these characteristics of SB431542 by loading it into liposomes (SB-Lips) with two FDA-approved excipients: soya phosphatidyl S100 and Solutol HS15. In vitro, SB-Lips had stronger inhibitory effects on the proliferation and activation of hepatic stellate cells LX-2 than free SB. After an intravenous injection in a CCl4-induced liver fibrosis mouse model, SB-Lips accumulated preferentially in the liver, its area under the concentration-time curve was significantly higher than that of free SB431542, and it alleviated hepatic fibrosis significantly more than free drug, which was associated with greater inhibition of TGF-ß signaling. Furthermore, SB-Lips did not cause significant injury to other organs. These results suggest that our liposomal system is safe and effective for delivering SB431542 to fibrotic liver.
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Benzamidas/administración & dosificación , Benzamidas/farmacocinética , Dioxoles/administración & dosificación , Dioxoles/farmacocinética , Cirrosis Hepática Experimental/tratamiento farmacológico , Transducción de Señal/efectos de los fármacos , Factor de Crecimiento Transformador beta/metabolismo , Animales , Tetracloruro de Carbono/efectos adversos , Línea Celular , Modelos Animales de Enfermedad , Liberación de Fármacos , Células Estrelladas Hepáticas/efectos de los fármacos , Células Estrelladas Hepáticas/metabolismo , Humanos , Liposomas , Cirrosis Hepática Experimental/inducido químicamente , Masculino , Ratones , Ratones Endogámicos C57BL , Ratas , Ratas Sprague-Dawley , Distribución TisularRESUMEN
The diabetes medication canagliflozin (Cana) is a sodium glucose cotransporter 2 (SGLT2) inhibitor acting by increasing urinary glucose excretion and thus reducing hyperglycaemia. Cana treatment also reduces body weight. However, it remains unclear whether Cana could directly work on adipose tissue. In the present study, the pharmacological effects of Cana and the associated mechanism were investigated in adipocytes and mice. Stromal-vascular fractions (SVFs) were isolated from subcutaneous adipose tissue and differentiated into mature adipocytes. Our results show that Cana treatment directly increased cellular energy expenditure of adipocytes by inducing mitochondrial biogenesis independently of SGLT2 inhibition. Along with mitochondrial biogenesis, Cana also increased mitochondrial oxidative phosphorylation, fatty acid oxidation and thermogenesis. Mechanistically, Cana promoted mitochondrial biogenesis and function via an Adenosine monophosphate-activated protein kinase (AMPK) - silent information regulator 1 (Sirt1) - peroxisome proliferator-activated receptor γ coactivator-1α (Pgc-1α) signalling pathway. Consistently, in vivo study demonstrated that Cana increased AMPK phosphorylation and the expression of Sirt1 and Pgc-1α. The present study reveals a new therapeutic function for Cana in regulating energy homoeostasis. ABBREVIATIONS: Ucp-1, uncoupling protein 1; cAMP, cyclic adenosine monophosphate; PKA, cAMP-dependent protein kinase A; SGLT, sodium glucose cotransporter; Cana, canagliflozin; T2DM: type 2 diabetes; Veh, vehicle; Pgc-1α, peroxisome proliferator-activated receptor γ coactivator-1α; SVFs, stromal-vascular fractions; FBS, bovine serum; Ad, adenovirus; mtDNA, mitochondrial DNA; COX2, cytochrome oxidase subunit 2; RT-PCR, real-time PCR; SDS-PAGE, sodium dodecyl sulphate-polyacrylamide gel electrophoresis; Prdm16, PR domain zinc finger protein 16; Cidea, cell death inducing DFFA-like effector A; Pgc-1ß, peroxisome proliferator-activated receptor γ coactivator-1ß; NRF1, nuclear respiratory factor 1; Tfam, mitochondrial transcription factor A; OXPHOS, oxidative phosphorylation; FAO, fatty acid oxidation; AMPK, Adenosine monophosphate-activated protein kinase; p-AMPK, phosphorylated AMPK; Sirt1, silent information regulator 1; mTOR, mammalian target of rapamycin; WAT, white adipose tissue; Fabp4, fatty acid binding protein 4; Lpl, lipoprotein lipase; Slc5a2, solute carrier family 5 member 2; ERRα, oestrogen related receptor α; Uqcrc2, ubiquinol-cytochrome c reductase core protein 2; Uqcrfs1, ubiquinol-cytochrome c reductase, Rieske iron-sulphur polypeptide 1; Cox4, cytochrome c oxidase subunit 4; Pparα, peroxisome proliferator activated receptor α; NAD+, nicotinamide adenine dinucleotide; Dio2, iodothyronine deiodinase 2; Tmem26, transmembrane protein 26; Hoxa9, homeobox A9; FCCP, carbonyl cyanide 4-(trifluoromethoxy) phenylhydrazone; Rot/AA, rotenone/antimycin A; OCR, oxygen consumption rate; Pparγ, peroxisome proliferator activated receptor γ; C/ebp, CCAAT/enhancer binding protein; LKB1, liver kinase B1; AUC, area under the cure; Vd, apparent volume of distribution.
Asunto(s)
Proteínas Quinasas Activadas por AMP/metabolismo , Adipocitos/metabolismo , Canagliflozina/farmacología , Mitocondrias/efectos de los fármacos , Mitocondrias/metabolismo , Coactivador 1-alfa del Receptor Activado por Proliferadores de Peroxisomas gamma/metabolismo , Transducción de Señal/efectos de los fármacos , Sirtuina 1/metabolismo , Animales , Metabolismo Energético , Ácidos Grasos/metabolismo , Regulación de la Expresión Génica/efectos de los fármacos , Masculino , Ratones , Mitocondrias/genética , Modelos Biológicos , Biogénesis de Organelos , Oxidación-Reducción , Fosforilación Oxidativa , Sirtuina 1/genética , TermogénesisRESUMEN
OBJECTIVE: To evaluate the efficacy and safety of the addition of local infiltration analgesia (LIA) to adductor canal block (ACB) for pain control after primary total knee arthroplasty (TKA). METHODS: Two reviewers independently searched for potentially relevant published studies using electronic databases, including PubMed® (1966 to June 2019), Embase® (1974 to June 2019) and Web of Science (1990 to June 2019). The results were pooled using the random-effects model to produce standard mean differences for continuous outcome data and odds ratio for categorical outcome data. RESULTS: A total of three randomized controlled trials (RCTs) and three non-RCTs were included for data extraction and meta-analysis. There were significant differences between the two groups regarding the postoperative pain score on postoperative day (POD) 0 and POD 1. The cumulative opioid consumption in the ACB plus LIA groups was significantly lower than that in the ACB groups on POD 0 and POD 1. No significant differences were found in terms of postoperative range of motion or length of hospitalization. CONCLUSION: ACB plus LIA significantly reduced the postoperative pain score on POD 0 and POD 1 compared with isolated ACB. In addition, ACB plus LIA was associated with a significant reduction in opioid consumption during the early postoperative period.
Asunto(s)
Analgesia , Artroplastia de Reemplazo de Rodilla , Bloqueo Nervioso , Analgésicos Opioides/uso terapéutico , Artroplastia de Reemplazo de Rodilla/efectos adversos , Humanos , Dolor Postoperatorio/tratamiento farmacológico , Dolor Postoperatorio/prevención & controlRESUMEN
OBJECTIVE: Sirt6 is an essential regulator of energy metabolism in multiple peripheral tissues. However, the direct role of Sirt6 in the hypothalamus, specifically pro-opiomelanocortin (POMC) neurons, controlling energy balance has not been established. Here, we aimed to determine the role of Sirt6 in hypothalamic POMC neurons in the regulation of energy balance and the underlying mechanisms. METHODS: For overexpression studies, the hypothalamic arcuate nucleus (ARC) of diet-induced obese mice was targeted bilaterally and adenovirus was delivered by using stereotaxic apparatus. For knockout studies, the POMC neuron-specific Sirt6 knockout mice (PKO mice) were generated. Mice were fed with chow diet or high-fat diet, and body weight and food intake were monitored. Whole-body energy expenditure was determined by metabolic cages. Parameters of body composition and glucose/lipid metabolism were evaluated. RESULTS: Sirt6 overexpression in the ARC ameliorated diet-induced obesity. Conversely, selective Sirt6 ablation in POMC neurons predisposed mice to obesity and metabolic disturbances. PKO mice showed an increased fat mass and food intake, while the energy expenditure was decreased. Mechanistically, Sirt6 could modulate leptin signaling in hypothalamic POMC neurons, with Sirt6 deficiency impairing leptin-induced phosphorylation of signal transducer and activator of transcription 3. The effects of leptin on reducing food intake and body weight and leptin-stimulated lipolysis were also impaired. Moreover, Sirt6 inhibition diminished the leptin-induced depolarization of POMC neurons. CONCLUSIONS: Our results reveal a key role of Sirt6 in POMC neurons against energy imbalance, suggesting that Sirt6 is an important molecular regulator for POMC neurons to promote negative energy balance.
Asunto(s)
Leptina/metabolismo , Neuronas/metabolismo , Sirtuinas/metabolismo , Animales , Núcleo Arqueado del Hipotálamo/metabolismo , Composición Corporal , Peso Corporal , Encéfalo/metabolismo , Dieta Alta en Grasa , Metabolismo Energético/fisiología , Hipotálamo/metabolismo , Leptina/fisiología , Masculino , Ratones , Ratones Endogámicos C57BL , Ratones Noqueados , Ratones Obesos , Obesidad/metabolismo , Proopiomelanocortina/metabolismo , Transducción de Señal/fisiología , Sirtuinas/fisiologíaRESUMEN
Renal fibrosis often occurs in chronic kidney disease, and effective treatment is needed. Celastrol (CEL) may attenuate renal fibrosis, but it distributes throughout the body, leading to severe systemic toxicities. Here we designed a system to deliver CEL specifically to interstitial myofibroblasts, which is a key driver of renal fibrogenesis. Fibronectin is highly expressed in fibrotic kidney. The pentapeptide CREKA, which specifically binds fibronectin, was conjugated to PEGylated liposomes (CREKA-Lip). CREKA-coupled liposomes significantly increased the uptake of unmodified liposomes by activated NRK-49F renal fibroblasts. Systemic administration of CREKA-Lip to mice led to their accumulation in fibrotic kidney, where they were specifically internalized by interstitial myofibroblasts. Loading CEL into CREKA-Lip effectively inhibited the activation and proliferation of NRK-49F cells in vitro, and they markedly alleviated renal fibrosis, injury and inflammation induced by unilateral ureteral obstruction in mice. Besides, CEL-loaded CREKA-Lip was associated with significantly lower toxicity to major organs than free CEL. These results suggest that encapsulating CEL in CREKA-Lip can increase its therapeutic efficacy and reduce its systemic toxicity as a potential treatment for renal fibrosis.