Your browser doesn't support javascript.
loading
Mostrar: 20 | 50 | 100
Resultados 1 - 20 de 54
Filtrar
1.
Cell ; 166(4): 867-880, 2016 Aug 11.
Artículo en Inglés | MEDLINE | ID: mdl-27518562

RESUMEN

We report that astrocytic insulin signaling co-regulates hypothalamic glucose sensing and systemic glucose metabolism. Postnatal ablation of insulin receptors (IRs) in glial fibrillary acidic protein (GFAP)-expressing cells affects hypothalamic astrocyte morphology, mitochondrial function, and circuit connectivity. Accordingly, astrocytic IR ablation reduces glucose-induced activation of hypothalamic pro-opio-melanocortin (POMC) neurons and impairs physiological responses to changes in glucose availability. Hypothalamus-specific knockout of astrocytic IRs, as well as postnatal ablation by targeting glutamate aspartate transporter (GLAST)-expressing cells, replicates such alterations. A normal response to altering directly CNS glucose levels in mice lacking astrocytic IRs indicates a role in glucose transport across the blood-brain barrier (BBB). This was confirmed in vivo in GFAP-IR KO mice by using positron emission tomography and glucose monitoring in cerebral spinal fluid. We conclude that insulin signaling in hypothalamic astrocytes co-controls CNS glucose sensing and systemic glucose metabolism via regulation of glucose uptake across the BBB.


Asunto(s)
Astrocitos/metabolismo , Glucosa/metabolismo , Hipotálamo/metabolismo , Insulina/metabolismo , Transducción de Señal , Sistema de Transporte de Aminoácidos X-AG/genética , Sistema de Transporte de Aminoácidos X-AG/metabolismo , Animales , Barrera Hematoencefálica , Retículo Endoplásmico/metabolismo , Proteína Ácida Fibrilar de la Glía/genética , Proteína Ácida Fibrilar de la Glía/metabolismo , Homeostasis , Ratones , Mitocondrias/metabolismo , Neuronas/citología , Neuronas/metabolismo , Proopiomelanocortina/metabolismo , Receptor de Insulina/genética , Receptor de Insulina/metabolismo
2.
Mol Cell ; 74(4): 844-857.e7, 2019 05 16.
Artículo en Inglés | MEDLINE | ID: mdl-31000437

RESUMEN

Brown adipose tissue (BAT) is rich in mitochondria and plays important roles in energy expenditure, thermogenesis, and glucose homeostasis. We find that levels of mitochondrial protein succinylation and malonylation are high in BAT and subject to physiological and genetic regulation. BAT-specific deletion of Sirt5, a mitochondrial desuccinylase and demalonylase, results in dramatic increases in global protein succinylation and malonylation. Mass spectrometry-based quantification of succinylation reveals that Sirt5 regulates the key thermogenic protein in BAT, UCP1. Mutation of the two succinylated lysines in UCP1 to acyl-mimetic glutamine and glutamic acid significantly decreases its stability and activity. The reduced function of UCP1 and other proteins in Sirt5KO BAT results in impaired mitochondria respiration, defective mitophagy, and metabolic inflexibility. Thus, succinylation of UCP1 and other mitochondrial proteins plays an important role in BAT and in regulation of energy homeostasis.


Asunto(s)
Metabolismo Energético/genética , Mitocondrias/metabolismo , Obesidad/genética , Sirtuinas/genética , Proteína Desacopladora 1/genética , Tejido Adiposo Pardo/metabolismo , Tejido Adiposo Pardo/patología , Animales , Regulación de la Expresión Génica , Glucosa/metabolismo , Ratones , Ratones Noqueados , Mitocondrias/genética , Proteínas Mitocondriales/genética , Obesidad/metabolismo , Obesidad/patología , Proteómica/métodos , Ácido Succínico/metabolismo , Termogénesis/genética , Proteína Desacopladora 1/metabolismo
3.
Proc Natl Acad Sci U S A ; 120(21): e2220684120, 2023 05 23.
Artículo en Inglés | MEDLINE | ID: mdl-37186836

RESUMEN

Brain insulin signaling controls peripheral energy metabolism and plays a key role in the regulation of mood and cognition. Epidemiological studies have indicated a strong connection between type 2 diabetes (T2D) and neurodegenerative disorders, especially Alzheimer's disease (AD), linked via dysregulation of insulin signaling, i.e., insulin resistance. While most studies have focused on neurons, here, we aim to understand the role of insulin signaling in astrocytes, a glial cell type highly implicated in AD pathology and AD progression. To this end, we created a mouse model by crossing 5xFAD transgenic mice, a well-recognized AD mouse model that expresses five familial AD mutations, with mice carrying a selective, inducible insulin receptor (IR) knockout in astrocytes (iGIRKO). We show that by age 6 mo, iGIRKO/5xFAD mice exhibited greater alterations in nesting, Y-maze performance, and fear response than those of mice with the 5xFAD transgenes alone. This was associated with increased Tau (T231) phosphorylation, increased Aß plaque size, and increased association of astrocytes with plaques in the cerebral cortex as assessed using tissue CLARITY of the brain in the iGIRKO/5xFAD mice. Mechanistically, in vitro knockout of IR in primary astrocytes resulted in loss of insulin signaling, reduced ATP production and glycolic capacity, and impaired Aß uptake both in the basal and insulin-stimulated states. Thus, insulin signaling in astrocytes plays an important role in the control of Aß uptake, thereby contributing to AD pathology, and highlighting the potential importance of targeting insulin signaling in astrocytes as a site for therapeutics for patients with T2D and AD.


Asunto(s)
Enfermedad de Alzheimer , Diabetes Mellitus Tipo 2 , Ratones , Animales , Enfermedad de Alzheimer/metabolismo , Péptidos beta-Amiloides/metabolismo , Precursor de Proteína beta-Amiloide/metabolismo , Astrocitos/metabolismo , Insulina/metabolismo , Diabetes Mellitus Tipo 2/metabolismo , Ratones Transgénicos , Fenotipo , Modelos Animales de Enfermedad
4.
Mol Psychiatry ; 2024 Aug 09.
Artículo en Inglés | MEDLINE | ID: mdl-39122778

RESUMEN

Astrocytes are multi-functional glial cells in the central nervous system that play critical roles in modulation of metabolism, extracellular ion and neurotransmitter levels, and synaptic plasticity. Astrocyte-derived signaling molecules mediate many of these modulatory functions of astrocytes, including vesicular release of ATP. In the present study, we used a unique genetic mouse model to investigate the functional significance of astrocytic exocytosis of ATP. Using primary cultured astrocytes, we show that loss of vesicular nucleotide transporter (Vnut), a primary transporter responsible for loading cytosolic ATP into the secretory vesicles, dramatically reduces ATP loading into secretory lysosomes and ATP release, without any change in the molecular machinery of exocytosis or total intracellular ATP content. Deletion of astrocytic Vnut in adult mice leads to increased anxiety, depressive-like behaviors, and decreased motivation for reward, especially in females, without significant impact on food intake, systemic glucose metabolism, cognition, or sociability. These behavioral alterations are associated with significant decreases in the basal extracellular dopamine levels in the nucleus accumbens. Likewise, ex vivo brain slices from these mice show a strong trend toward a reduction in evoked dopamine release in the nucleus accumbens. Mechanistically, the reduced dopamine signaling we observed is likely due to an increased expression of monoamine oxidases. Together, these data demonstrate a key modulatory role of astrocytic exocytosis of ATP in anxiety, depressive-like behavior, and motivation for reward, by regulating the mesolimbic dopamine circuitry.

5.
Glycobiology ; 34(2)2024 Mar 26.
Artículo en Inglés | MEDLINE | ID: mdl-38015989

RESUMEN

Heparan sulfate (HS) is a linear polysaccharide that plays a key role in cellular signaling networks. HS functions are regulated by its 6-O-sulfation, which is catalyzed by three HS 6-O-sulfotransferases (HS6STs). Notably, HS6ST2 is mainly expressed in the brain and HS6ST2 mutations are linked to brain disorders, but the underlying mechanisms remain poorly understood. To determine the role of Hs6st2 in the brain, we carried out a series of molecular and behavioral assessments on Hs6st2 knockout mice. We first carried out strong anion exchange-high performance liquid chromatography and found that knockout of Hs6st2 moderately decreases HS 6-O-sulfation levels in the brain. We then assessed body weights and found that Hs6st2 knockout mice exhibit increased body weight, which is associated with abnormal metabolic pathways. We also performed behavioral tests and found that Hs6st2 knockout mice showed memory deficits, which recapitulate patient clinical symptoms. To determine the molecular mechanisms underlying the memory deficits, we used RNA sequencing to examine transcriptomes in two memory-related brain regions, the hippocampus and cerebral cortex. We found that knockout of Hs6st2 impairs transcriptome in the hippocampus, but only mildly in the cerebral cortex. Furthermore, the transcriptome changes in the hippocampus are enriched in dendrite and synapse pathways. We also found that knockout of Hs6st2 decreases HS levels and impairs dendritic spines in hippocampal CA1 pyramidal neurons. Taken together, our study provides novel molecular and behavioral insights into the role of Hs6st2 in the brain, which facilitates a better understanding of HS6ST2 and HS-linked brain disorders.


Asunto(s)
Encefalopatías , Discapacidad Intelectual , Sulfotransferasas , Animales , Humanos , Ratones , Espinas Dendríticas/metabolismo , Heparitina Sulfato/metabolismo , Hipocampo/metabolismo , Trastornos de la Memoria , Ratones Noqueados , Neuronas/metabolismo , Compuestos de Pralidoxima , Sulfotransferasas/genética , Sulfotransferasas/metabolismo
6.
FASEB J ; 37(10): e23185, 2023 10.
Artículo en Inglés | MEDLINE | ID: mdl-37695721

RESUMEN

Sensory neurons in the dorsal root ganglia (DRG) convey somatosensory and metabolic cues to the central nervous system and release substances from stimulated terminal endings in peripheral organs. Sex-biased variations driven by the sex chromosome complement (XX and XY) have been implicated in the sensory-islet crosstalk. However, the molecular underpinnings of these male-female differences are not known. Here, we aim to characterize the molecular repertoire and the secretome profile of the lower thoracic spinal sensory neurons and to identify molecules with sex-biased insulin sensing- and/or insulin secretion-modulating activity that are encoded independently of circulating gonadal sex hormones. We used transcriptomics and proteomics to uncover differentially expressed genes and secreted molecules in lower thoracic T5-12 DRG sensory neurons derived from sexually immature 3-week-old male and female C57BL/6J mice. Comparative transcriptome and proteome analyses revealed differential gene expression and protein secretion in DRG neurons in males and females. The transcriptome analysis identified, among others, higher insulin signaling/sensing capabilities in female DRG neurons; secretome screening uncovered several sex-specific candidate molecules with potential regulatory functions in pancreatic ß cells. Together, these data suggest a putative role of sensory interoception of insulin in the DRG-islet crosstalk with implications in sensory feedback loops in the regulation of ß-cell activity in a sex-biased manner. Finally, we provide a valuable resource of molecular and secretory targets that can be leveraged for understanding insulin interoception and insulin secretion and inform the development of novel studies/approaches to fathom the role of the sensory-islet axis in the regulation of energy balance in males and females.


Asunto(s)
Insulina , Transcriptoma , Femenino , Masculino , Ratones , Animales , Ratones Endogámicos C57BL , Secreción de Insulina , Caracteres Sexuales , Secretoma , Células Receptoras Sensoriales
7.
Proc Natl Acad Sci U S A ; 118(17)2021 04 27.
Artículo en Inglés | MEDLINE | ID: mdl-33879610

RESUMEN

Insulin and insulin-like growth factor 1 (IGF-1) receptors share many downstream signaling pathways but have unique biological effects. To define the molecular signals contributing to these distinct activities, we performed global phosphoproteomics on cells expressing either insulin receptor (IR), IGF-1 receptor (IGF1R), or chimeric IR-IGF1R receptors. We show that IR preferentially stimulates phosphorylations associated with mammalian target of rapamycin complex 1 (mTORC1) and Akt pathways, whereas IGF1R preferentially stimulates phosphorylations on proteins associated with the Ras homolog family of guanosine triphosphate hydrolases (Rho GTPases), and cell cycle progression. There were also major differences in the phosphoproteome between cells expressing IR versus IGF1R in the unstimulated state, including phosphorylation of proteins involved in membrane trafficking, chromatin remodeling, and cell cycle. In cells expressing chimeric IR-IGF1R receptors, these differences in signaling could be mapped to contributions of both the extra- and intracellular domains of these receptors. Thus, despite their high homology, IR and IGF1R preferentially regulate distinct networks of phosphorylation in both the basal and stimulated states, allowing for the unique effects of these hormones on organismal function.


Asunto(s)
Antígenos CD/metabolismo , Receptor IGF Tipo 1/metabolismo , Receptor de Insulina/metabolismo , Adipocitos/metabolismo , Animales , División Celular/efectos de los fármacos , Línea Celular , Femenino , Humanos , Insulina/metabolismo , Factor I del Crecimiento Similar a la Insulina/metabolismo , Masculino , Diana Mecanicista del Complejo 1 de la Rapamicina/fisiología , Ratones , Fosfatos de Fosfatidilinositol/metabolismo , Fosforilación/efectos de los fármacos , Proteínas Proto-Oncogénicas c-akt/metabolismo , Transducción de Señal/genética , Transducción de Señal/fisiología , Proteínas de Unión al GTP rho/metabolismo
8.
Proc Natl Acad Sci U S A ; 117(12): 6733-6740, 2020 03 24.
Artículo en Inglés | MEDLINE | ID: mdl-32156724

RESUMEN

Insulin action in the liver is critical for glucose homeostasis through regulation of glycogen synthesis and glucose output. Arrestin domain-containing 3 (Arrdc3) is a member of the α-arrestin family previously linked to human obesity. Here, we show that Arrdc3 is differentially regulated by insulin in vivo in mice undergoing euglycemic-hyperinsulinemic clamps, being highly up-regulated in liver and down-regulated in muscle and fat. Mice with liver-specific knockout (KO) of the insulin receptor (IR) have a 50% reduction in Arrdc3 messenger RNA, while, conversely, mice with liver-specific KO of Arrdc3 (L-Arrdc3 KO) have increased IR protein in plasma membrane. This leads to increased hepatic insulin sensitivity with increased phosphorylation of FOXO1, reduced expression of PEPCK, and increased glucokinase expression resulting in reduced hepatic glucose production and increased hepatic glycogen accumulation. These effects are due to interaction of ARRDC3 with IR resulting in phosphorylation of ARRDC3 on a conserved tyrosine (Y382) in the carboxyl-terminal domain. Thus, Arrdc3 is an insulin target gene, and ARRDC3 protein directly interacts with IR to serve as a feedback regulator of insulin action in control of liver metabolism.


Asunto(s)
Arrestinas/fisiología , Glucosa/metabolismo , Resistencia a la Insulina , Insulina/farmacología , Hígado/metabolismo , Receptor de Insulina/fisiología , Animales , Membrana Celular/metabolismo , Proteína Forkhead Box O1/metabolismo , Hipoglucemiantes/farmacología , Hígado/efectos de los fármacos , Ratones , Ratones Endogámicos C57BL , Ratones Noqueados , Fosforilación
9.
Am J Physiol Heart Circ Physiol ; 323(2): H301-H311, 2022 08 01.
Artículo en Inglés | MEDLINE | ID: mdl-35749717

RESUMEN

Obesity-related cardiovascular complications are a major health problem worldwide. Overconsumption of the Western diet is a well-known culprit for the development of obesity. Although short-term weight loss through switching from a Western diet to a normal diet is known to promote metabolic improvement, its short-term effects on vascular parameters are not well characterized. Glucagon-like peptide 1 (GLP-1), an incretin with vasculoprotective properties, is decreased in plasma from patients who are obese. We hypothesize that obesity causes persistent vascular dysfunction in association with the downregulation of vascular glucagon-like peptide 1 receptor (GLP-1R). Female Wistar rats were randomized into three groups: lean received a chow diet for 28 wk, obese received a Western diet for 28 wk, and reverse obese received a Western diet for 18 wk followed by 12 wk of standard chow diet. The obese group exhibited increased body weight and body mass index, whereas the reverse obese group lost weight. Weight loss failed to reverse impaired vasodilation and high systolic blood pressure in obese rats. Strikingly, our results show that obese rats exhibit decreased serum levels of GLP-1 accompanied by decreased vascular GLP-1R expression. Weight loss recovered GLP-1 serum levels, however GLP-1R expression remained downregulated. Decreased Akt phosphorylation was observed in the obese and reverse obese group, suggesting that GLP-1/Akt signaling is persistently downregulated. Our results support that GLP-1 signaling is associated with obesity-related vascular dysfunction in females, and short-term weight loss does not guarantee recovery of vascular function. This study suggests that GLP-1R may be a potential target for therapeutic intervention in obesity-related hypertension in females.NEW & NOTEWORTHY Although short-term weight loss successfully improved metabolic parameters, it failed to correct vascular dysfunction present in obese female rats. Vascular GLP-1/Akt signaling was decreased in both obese rats and those with short-term weight loss, suggesting it may be a potential target for therapeutic intervention in obesity-related persistent vascular dysfunction in obese females.


Asunto(s)
Receptores de Péptidos Similares al Glucagón , Proteínas Proto-Oncogénicas c-akt , Animales , Peso Corporal , Femenino , Péptido 1 Similar al Glucagón , Receptor del Péptido 1 Similar al Glucagón/metabolismo , Obesidad/metabolismo , Ratas , Ratas Wistar , Pérdida de Peso/fisiología
10.
Proc Natl Acad Sci U S A ; 116(13): 6379-6384, 2019 03 26.
Artículo en Inglés | MEDLINE | ID: mdl-30765523

RESUMEN

Previous studies have shown that insulin and IGF-1 signaling in the brain, especially the hypothalamus, is important for regulation of systemic metabolism. Here, we develop mice in which we have specifically inactivated both insulin receptors (IRs) and IGF-1 receptors (IGF1Rs) in the hippocampus (Hippo-DKO) or central amygdala (CeA-DKO) by stereotaxic delivery of AAV-Cre into IRlox/lox/IGF1Rlox/lox mice. Consequently, both Hippo-DKO and CeA-DKO mice have decreased levels of the GluA1 subunit of glutamate AMPA receptor and display increased anxiety-like behavior, impaired cognition, and metabolic abnormalities, including glucose intolerance. Hippo-DKO mice also display abnormal spatial learning and memory whereas CeA-DKO mice have impaired cold-induced thermogenesis. Thus, insulin/IGF-1 signaling has common roles in the hippocampus and central amygdala, affecting synaptic function, systemic glucose homeostasis, behavior, and cognition. In addition, in the hippocampus, insulin/IGF-1 signaling is important for spatial learning and memory whereas insulin/IGF-1 signaling in the central amygdala controls thermogenesis via regulation of neural circuits innervating interscapular brown adipose tissue.


Asunto(s)
Conducta Animal , Núcleo Amigdalino Central/metabolismo , Hipocampo/metabolismo , Insulina/metabolismo , Transducción de Señal , Tejido Adiposo Pardo/metabolismo , Animales , Ansiedad , Encefalopatías Metabólicas , Glucosa/metabolismo , Intolerancia a la Glucosa , Homeostasis , Factor I del Crecimiento Similar a la Insulina/metabolismo , Memoria , Ratones , Ratones Noqueados , Receptor IGF Tipo 1/metabolismo , Receptor de Insulina/metabolismo , Aprendizaje Espacial , Termogénesis
11.
Proc Natl Acad Sci U S A ; 115(10): 2461-2466, 2018 03 06.
Artículo en Inglés | MEDLINE | ID: mdl-29467286

RESUMEN

Viruses are the most abundant biological entities and carry a wide variety of genetic material, including the ability to encode host-like proteins. Here we show that viruses carry sequences with significant homology to several human peptide hormones including insulin, insulin-like growth factors (IGF)-1 and -2, FGF-19 and -21, endothelin-1, inhibin, adiponectin, and resistin. Among the strongest homologies were those for four viral insulin/IGF-1-like peptides (VILPs), each encoded by a different member of the family Iridoviridae VILPs show up to 50% homology to human insulin/IGF-1, contain all critical cysteine residues, and are predicted to form similar 3D structures. Chemically synthesized VILPs can bind to human and murine IGF-1/insulin receptors and stimulate receptor autophosphorylation and downstream signaling. VILPs can also increase glucose uptake in adipocytes and stimulate the proliferation of fibroblasts, and injection of VILPs into mice significantly lowers blood glucose. Transfection of mouse hepatocytes with DNA encoding a VILP also stimulates insulin/IGF-1 signaling and DNA synthesis. Human microbiome studies reveal the presence of these Iridoviridae in blood and fecal samples. Thus, VILPs are members of the insulin/IGF superfamily with the ability to be active on human and rodent cells, raising the possibility for a potential role of VILPs in human disease. Furthermore, since only 2% of viruses have been sequenced, this study raises the potential for discovery of other viral hormones which, along with known virally encoded growth factors, may modify human health and disease.


Asunto(s)
Interacciones Huésped-Patógeno/fisiología , Factor I del Crecimiento Similar a la Insulina/metabolismo , Insulina/metabolismo , Receptor IGF Tipo 1/metabolismo , Proteínas Virales/metabolismo , Virus/genética , Animales , Línea Celular , Proliferación Celular , Glucosa/metabolismo , Hepatocitos , Humanos , Insulina/genética , Masculino , Ratones , Ratones Endogámicos C57BL , Transducción de Señal , Proteínas Virales/genética , Virosis/virología
12.
Molecules ; 26(24)2021 Dec 12.
Artículo en Inglés | MEDLINE | ID: mdl-34946610

RESUMEN

Critical limb ischemia (CLI) is a severe form of peripheral artery diseases (PAD) and seriously endangers the health of people. Therapeutic angiogenesis represents an important treatment strategy for CLI; various methods have been applied to enhance collateral circulation. However, the current development drug therapy to promote angiogenesis is limited. Resveratrol (RSV), a polyphenol compound extracted from plants, has various properties such as anti-oxidative, anti-inflammatory and anti-cancer effects. Whether RSV exerts protective effects on CLI remains elusive. In the current study, we demonstrated that oral intake of RSV significantly improved hind limb ischemia in mice, and increased the expression of phosphorylated Forkhead box class-O1 (FoxO1). RSV treatment in human umbilical vein endothelial cells (HUVECs) could increase the phosphorylation of FoxO1 and its cytoplasmic re-localization to promote angiogenesis. Then we manipulated FoxO1 in HUVECs to further verify that the effect of RSV on angiogenesis is in a FoxO1-dependent manner. Furthermore, we performed metabolomics to screen the metabolic pathways altered upon RSV intervention. We found that the pathways of pyrimidine metabolism, purine metabolism, as well as alanine, aspartate and glutamate metabolism, were highly correlated with the beneficial effects of RSV on the ischemic muscle. This study provides a novel direction for the medical therapy to CLI.


Asunto(s)
Isquemia Crónica que Amenaza las Extremidades/tratamiento farmacológico , Proteína Forkhead Box O1/metabolismo , Neovascularización Patológica/tratamiento farmacológico , Resveratrol/farmacología , Animales , Isquemia Crónica que Amenaza las Extremidades/metabolismo , Proteína Forkhead Box O1/genética , Células Endoteliales de la Vena Umbilical Humana/efectos de los fármacos , Células Endoteliales de la Vena Umbilical Humana/metabolismo , Humanos , Metabolómica , Ratones , Ratones Endogámicos C57BL , Neovascularización Patológica/metabolismo , Fosforilación/efectos de los fármacos
13.
Proc Natl Acad Sci U S A ; 114(40): E8478-E8487, 2017 10 03.
Artículo en Inglés | MEDLINE | ID: mdl-28923931

RESUMEN

Insulin receptors (IRs) on endothelial cells may have a role in the regulation of transport of circulating insulin to its target tissues; however, how this impacts on insulin action in vivo is unclear. Using mice with endothelial-specific inactivation of the IR gene (EndoIRKO), we find that in response to systemic insulin stimulation, loss of endothelial IRs caused delayed onset of insulin signaling in skeletal muscle, brown fat, hypothalamus, hippocampus, and prefrontal cortex but not in liver or olfactory bulb. At the level of the brain, the delay of insulin signaling was associated with decreased levels of hypothalamic proopiomelanocortin, leading to increased food intake and obesity accompanied with hyperinsulinemia and hyperleptinemia. The loss of endothelial IRs also resulted in a delay in the acute hypoglycemic effect of systemic insulin administration and impaired glucose tolerance. In high-fat diet-treated mice, knockout of the endothelial IRs accelerated development of systemic insulin resistance but not food intake and obesity. Thus, IRs on endothelial cells have an important role in transendothelial insulin delivery in vivo which differentially regulates the kinetics of insulin signaling and insulin action in peripheral target tissues and different brain regions. Loss of this function predisposes animals to systemic insulin resistance, overeating, and obesity.


Asunto(s)
Encéfalo/metabolismo , Resistencia a la Insulina , Insulina/metabolismo , Hígado/metabolismo , Músculo Esquelético/metabolismo , Obesidad/fisiopatología , Receptor de Insulina/fisiología , Animales , Glucemia/metabolismo , Intolerancia a la Glucosa , Cinética , Masculino , Ratones , Ratones Endogámicos C57BL , Ratones Noqueados , Transducción de Señal
14.
J Biol Chem ; 292(6): 2054-2064, 2017 02 10.
Artículo en Inglés | MEDLINE | ID: mdl-28007959

RESUMEN

Adult neurogenesis, the process of generating mature neurons from neuronal progenitor cells, makes critical contributions to neural circuitry and brain function in both healthy and disease states. Neurogenesis is a highly regulated process in which diverse environmental and physiological stimuli are relayed to resident neural stem cell populations to control the transcription of genes involved in self-renewal and differentiation. Understanding the molecular mechanisms governing neurogenesis is necessary for the development of translational strategies to harness this process for neuronal repair. Here we report that the Ras-related GTPase RIT1 serves to control the sequential proliferation and differentiation of adult hippocampal neural progenitor cells, with in vivo expression of active RIT1 driving robust adult neurogenesis. Gene expression profiling analysis demonstrates increased expression of a specific set of transcription factors known to govern adult neurogenesis in response to active RIT1 expression in the hippocampus, including sex-determining region Y-related HMG box 2 (Sox2), a well established regulator of stem cell self-renewal and neurogenesis. In adult hippocampal neuronal precursor cells, RIT1 controls an Akt-dependent signaling cascade, resulting in the stabilization and transcriptional activation of phosphorylated Sox2. This study supports a role for RIT1 in relaying niche-derived signals to neural/stem progenitor cells to control transcription of genes involved in self-renewal and differentiation.


Asunto(s)
Hipocampo/fisiología , Neurogénesis , Factores de Transcripción SOXB1/metabolismo , Transcripción Genética , Proteínas ras/metabolismo , Animales , Ratones , Ratones Transgénicos , Proteínas Proto-Oncogénicas c-akt/metabolismo , Transducción de Señal , Proteínas ras/genética
15.
Proc Natl Acad Sci U S A ; 112(11): 3463-8, 2015 Mar 17.
Artículo en Inglés | MEDLINE | ID: mdl-25733901

RESUMEN

Diabetes and insulin resistance are associated with altered brain imaging, depression, and increased rates of age-related cognitive impairment. Here we demonstrate that mice with a brain-specific knockout of the insulin receptor (NIRKO mice) exhibit brain mitochondrial dysfunction with reduced mitochondrial oxidative activity, increased levels of reactive oxygen species, and increased levels of lipid and protein oxidation in the striatum and nucleus accumbens. NIRKO mice also exhibit increased levels of monoamine oxidase A and B (MAO A and B) leading to increased dopamine turnover in these areas. Studies in cultured neurons and glia cells indicate that these changes in MAO A and B are a direct consequence of loss of insulin signaling. As a result, NIRKO mice develop age-related anxiety and depressive-like behaviors that can be reversed by treatment with MAO inhibitors, as well as the tricyclic antidepressant imipramine, which inhibits MAO activity and reduces oxidative stress. Thus, insulin resistance in brain induces mitochondrial and dopaminergic dysfunction leading to anxiety and depressive-like behaviors, demonstrating a potential molecular link between central insulin resistance and behavioral disorders.


Asunto(s)
Conducta Animal , Encéfalo/metabolismo , Dopamina/metabolismo , Resistencia a la Insulina , Envejecimiento/patología , Animales , Antidepresivos/farmacología , Antidepresivos/uso terapéutico , Ansiedad/metabolismo , Ansiedad/patología , Conducta Animal/efectos de los fármacos , Encéfalo/efectos de los fármacos , Encéfalo/patología , Encéfalo/ultraestructura , Depresión/patología , Ratones Endogámicos C57BL , Ratones Noqueados , Mitocondrias/efectos de los fármacos , Mitocondrias/metabolismo , Mitocondrias/patología , Mitocondrias/ultraestructura , Estrés Oxidativo/efectos de los fármacos , Receptor de Insulina/metabolismo , Transducción de Señal/efectos de los fármacos
16.
Front Med (Lausanne) ; 11: 1413593, 2024.
Artículo en Inglés | MEDLINE | ID: mdl-38947243

RESUMEN

Necrotizing fasciitis is an aggressive bacterial infection that causes necrosis of the fascia and subcutaneous tissues with rapid progression and high mortality. Early stages often lead to misdiagnosis, resulting in improper treatment and severe implications. This case study presents a patient with diabetes mellitus combined with hepatitis B who rapidly developed necrotizing fasciitis of the left forearm and left breast after trauma and controlled the infection with early surgical treatment. It is worth noting that early surgical exploration is the gold standard for the diagnosis of necrotizing fasciitis and is the most effective means of reducing mortality and amputation rates in necrotizing fasciitis.

17.
Artículo en Inglés | MEDLINE | ID: mdl-39214743

RESUMEN

Astrocytes, the predominant glial cell type in the mammalian brain, influence a wide variety of brain parameters including neuronal energy metabolism. Exciting recent studies have shown that obesity and diabetes can impact on astrocyte function. We review evidence that dysregulation of astrocytic lipid metabolism and glucose sensing contributes to dysregulation of whole-body energy balance, thermoregulation, and insulin sensitivity. In addition, we consider the overlooked topic of the sex-specific roles of astrocytes and their response to hormonal fluctuations that provide insights into sex differences in metabolic regulation. Finally, we provide an update on potential ways to manipulate astrocyte function, including genetic targeting, optogenetic and chemogenetic techniques, transplantation, and tailored exosome-based therapies, which may lead to improved treatments for metabolic disease.

18.
Artículo en Inglés | MEDLINE | ID: mdl-38684025

RESUMEN

Nowadays, food safety is still facing great challenges. During storage and transportation, perishable goods have to be kept at a low temperature. However, the current logistics still lack enough preservation ability to maintain a low temperature in the whole. Hence, considering the temperature fluctuation in logistics, in this work, the passive radiative cooling (RC) technology was applied to package to enhance the temperature control capability in food storage and transportation. The RC emitter with selective infrared emission property was fabricated by a facile coating method, and Al2O3 was added to improve the wear resistance. The sunlight reflectance and infrared emittance within atmospheric conditions could reach up to 0.92 and 0.84, respectively. After abrasion, the sunlight reflection only decreased by 0.01, and the infrared emission showed a negligible change, revealing excellent wear resistance. During outdoor measurement, the box assembled by RC emitters (RC box) was proved to achieve temperature drops of ∼9 and ∼4 °C compared with the corrugated box and foam box, respectively. Besides, the fruits stored in the RC box exhibited a lower decay rate. Additionally, after printing with patterns to meet the aesthetic requirements, the RC emitter could also maintain the cooling ability. Given the superior optical properties, wear resistance, and cooling capability, the emitter has great potential for obtaining a better temperature control ability in food storage and transportation.

19.
J Neurosci ; 32(29): 9887-97, 2012 Jul 18.
Artículo en Inglés | MEDLINE | ID: mdl-22815504

RESUMEN

The molecular mechanisms governing the spontaneous recovery seen following brain injury remain elusive, but recent studies indicate that injury-induced stimulation of hippocampal neurogenesis contributes to the repair process. The therapeutic potential of endogenous neurogenesis is tempered by the demonstration that traumatic brain injury (TBI) results in the selective death of adult-born immature neurons, compromising the cell population poised to compensate for trauma-induced neuronal loss. Here, we identify the Ras-related GTPase, Rit, as a critical player in the survival of immature hippocampal neurons following brain injury. While Rit knock-out (Rit(-/-)) did not alter hippocampal development, hippocampal neural cultures derived from Rit(-/-) mice display increased cell death and blunted MAPK cascade activation in response to oxidative stress, without affecting BDNF-dependent signaling. When compared with wild-type hippocampal cultures, Rit loss rendered immature (Dcx(+)) neurons susceptible to oxidative damage, without altering the survival of neural progenitor (Nestin(+)) cells. Oxidative stress is a major contributor to neuronal cell death following brain injury. Consistent with the enhanced vulnerability of cultured Rit(-/-) immature neurons, Rit(-/-) mice exhibited a significantly greater loss of adult-born immature neurons within the dentate gyrus after TBI. In addition, post-TBI neuronal remodeling was blunted. Together, these data identify a new and unexpected role for Rit in injury-induced neurogenesis, functioning as a selective survival mechanism for immature hippocampal neurons within the subgranular zone of the dentate gyrus following TBI.


Asunto(s)
Supervivencia Celular/fisiología , Hipocampo/metabolismo , Neurogénesis/fisiología , Neuronas/metabolismo , Transducción de Señal/fisiología , Proteínas ras/metabolismo , Animales , Lesiones Encefálicas/genética , Lesiones Encefálicas/metabolismo , Factor Neurotrófico Derivado del Encéfalo/metabolismo , Células Cultivadas , Dendritas/metabolismo , Proteína Doblecortina , Hipocampo/citología , Ratones , Ratones Noqueados , Neuronas/citología , Estrés Oxidativo/fisiología , Proteínas ras/genética
20.
J Biol Chem ; 287(47): 39859-68, 2012 Nov 16.
Artículo en Inglés | MEDLINE | ID: mdl-23038261

RESUMEN

The cAMP response element (CRE)-binding protein (CREB) is a key regulatory factor of gene transcription, and plays an essential role in development of the central nervous system and for neuroprotection. Multiple signaling pathways have been shown to contribute to the regulation of CREB-dependent transcription, including both ERK and p38 mitogen-activated protein (MAP) kinases cascades. Recent studies have identified the Ras-related small G-protein, Rit, as a central regulator of a p38-MK2-HSP27 signaling cascade that functions as a critical survival mechanism for cells adapting to stress. Here, we examine the contribution of Rit-p38 signaling to the control of stress-dependent gene transcription. Using a pheochromocytoma cell model, we find that a novel Rit-p38-MSK1/2 pathway plays a critical role in stress-mediated CREB activation. RNAi-mediated Rit silencing, or inhibition of p38 or MSK1/2 kinases, was found to disrupt stress-mediated CREB-dependent transcription, resulting in increased cell death. Furthermore, ectopic expression of active Rit stimulates CREB-Ser133 phosphorylation, induces expression of the anti-apoptotic Bcl-2 and Bcl(XL) proteins, and promotes cell survival. These data indicate that the Rit-p38-MSK1/2 signaling pathway may have an important role in the stress-dependent regulation of CREB-dependent gene expression.


Asunto(s)
Proteína de Unión a Elemento de Respuesta al AMP Cíclico/metabolismo , Sistema de Señalización de MAP Quinasas/fisiología , Proteínas Quinasas S6 Ribosómicas 90-kDa/metabolismo , Estrés Fisiológico/fisiología , Proteínas Quinasas p38 Activadas por Mitógenos/metabolismo , Proteínas ras/metabolismo , Animales , Proteína de Unión a Elemento de Respuesta al AMP Cíclico/genética , Regulación de la Expresión Génica/fisiología , Células HEK293 , Humanos , Ratones , Proteínas Quinasas S6 Ribosómicas 90-kDa/genética , Transcripción Genética/fisiología , Proteínas Quinasas p38 Activadas por Mitógenos/genética , Proteínas ras/genética
SELECCIÓN DE REFERENCIAS
DETALLE DE LA BÚSQUEDA