La inhibición de la proteína tirosina fosfatasa 1B protege frente a la apoptosis temprana inducida por paracetamol en hepatocitos

Premio “Consejo General de Colegios Oficiales de Farmacéuticos” en el Concurso Científico 2013 de la Real Academia Nacional de Farmacia.[EN]: Acetaminophen (paracetamol, APAP) is a widely used analgesic and antipyretic drug safe at therapeutic doses but its overdose causes liver injury. Our goal was to explore whether protein tyrosine phosphatase 1B (PTP1B), a negative modulator of survival signaling pathways, plays a role in APAP-induced cell death in hepatocytes. Hepatotoxicity was evaluated in immortalized hepatocytes generated from wild-type (PTP1B+/+) and PTP1B-deficient (PTP1B-/-) mice. Apoptosis occurred as an early event only in APAP-treated PTP1B+/+ hepatocytes. PTP1B deficiency conferred protection against cell cycle arrest and loss of cellular viability. These data suggest that PTP1B as a target against APAP-induced liver failure.[ES]: El paracetamol es un analgésico/antipirético hepatotóxico a dosis altas. Investigamos el papel de la proteína tirosina fosfatasa 1B (PTP1B), un modulador negativo de señalización de supervivencia celular, en la muerte celular temprana (apoptosis) inducida por paracetamol en hepatocitos. En hepatocitos controles se inducía apoptosis en respuesta al paracetamol. Este efecto se encontraba disminuido en hepatocitos deficientes en PTP1B. La falta de PTP1B protegía a los hepatocitos de la parada del ciclo celular y la pérdida de la viabilidad celular tras el tratamiento con paracetamol. Proponemos a la PTP1B como diana terapéutica frente al fallo hepático inducido por sobredosis de paracetamol.We acknowledge the following grant support: SAF2012-33283 (MINECO, Spain), Comunidad de Madrid S2010/BMD-2423, EFSD and Amylin Paul Langerhans Grant and Centro de Investigación Biomédica en Red de Diabetes y Enfermedades Metabólicas Asociadas (CIBERDEM, ISCIII, Spain).Peer Reviewe

El tratamiento de la inflamacion en la retina: una nueva estrategia terapéutica en la retinopatía diabética

[EN]: Retinal diseases linked to inflammation, including diabetic retinopathy (DR), are often accompanied by resident macrophage/microglial cells activation. During DR, there are substantial changes in the polarization status of the microglia from the M2 (anti-inflammatory) to the M1 (pro-inflammatory) stage. However, the dynamics between M1 and M2 polarization of microglia during DR has not been investigated and it might be therapeutically useful. In this study, we have characterized the evolution of microglia polarizarion during the early stages of DR in the retina of diabetic db/db mice. Moreover, we have analyzed microglia polarization in response to pro-(bacterial lipopolysaccharide; LPS) or anti-(IL4/IL13 cytokines or the bicyclic nojirimycin derivative (1R)-1-dodecylsulfinyl-5N,6O-oxomethylidenenojirimycin (RDS-ONJ)) inflammatory stimuli. For this goal, we have performed in vitro experiments in Bv-2 murine microglial cells as well as ex vivo experiments in retinal explants from db/db mice. Treatment of Bv-2 cells with LPS together with IL4/IL13 or R-DS-ONJ switched the M1 response towards M2. In retinal explants from db/db mice, R-DS-ONJ induced a M2 response. In conclusion, the modulation of microglia polarization dynamics towards a M2 status at early stages of DR offers novel therapeutic interventions.[ES]: Las enfermedades retinianas, entre las que se encuentra la retinopatía diabética (RD), están vinculadas a un contexto inflamatorio en el cual existe una activación de los macrófagos residentes en la retina (microglia). Durante la retinopatía diabética se producen cambios de polarización de la microglia, definiéndose éstos como transiciones entre el estado M1 (proinflamatorio) y el estado M2 (anti-inflamatorio), estando aún por determinar los tiempos de aparición y actuación de la microglia en cada uno de ellos. La identificación espacio-temporal de la transición de la microglía de un estado a otro podría constituir una potente herramienta clínica para diferentes abordajes terapéuticos. En este trabajo se ha caracterizado el estado de polarización de la microgía en la retina durante las primeras fases de la RD en el modelo de ratón diabético db/db. Además, se ha estudiado la polarización de la microglia en presencia de estímulos pro-inflamatorios (lipopolisacárido bacteriano; LPS) o anti-inflamatorios (citoquinas IL4/IL13 o un compuesto natural derivado de la casternospermina, R-DS-ONJ). Para ello, se ha realizado un abordaje in vitro utilizando la línea celular de microglia murina Bv-2 y un abordaje ex vivo con explantes de retinas procedentes de ratones diabéticos db/db. El tratamiento de las células Bv-2 con LPS en combinación con IL4/IL13 o alternativamente con el compuesto R-DS-ONJ indujo la transición en la polarización de la microglia desde el estado proinflamatorio M1, inducido por el LPS, al estado antiinflamatorio M2. En los explantes de retinas de ratones db/db, el compuesto R-DS-ONJ indujo la respuesta M2 disminuyendo la respuesta M1. En conclusión, la polarización de la microglia hacía un estado M2 durante los estadíos tempranos de la RD ofrece una nueva ventana terapéutica de actuación.This work was supported by grants from the Spanish Ministry of Economy and Competitivity (SAF2015-65267-R and SAF2012-33283), Comunidad de Madrid S2010/BMD-2423 and S2010/BMD2439, Centro de Investigación Biomédica en Red de Diabetes y Enfermedades Metabólicas Asociadas (CIBERdem, Instituto Carlos III, Spain), European Union (EUROCONDOR (FP7 HEALTH.2011.2.4.3.1.)).Peer Reviewe

Adipose tissue as a target for second-generation (atypical) antipsychotics: A molecular view

Schizophrenia is a neuropsychiatric disorder that chronically affects 21 million people worldwide. Secondgeneration antipsychotics (SGAs) are the cornerstone in the management of schizophrenia. However, despite their efficacy in counteracting both positive and negative symptomatology of schizophrenia, recent clinical observations have described an increase in the prevalence of metabolic disturbances in patients treated with SGAs, including abnormal weight gain, hyperglycemia and dyslipidemia. While the molecular mechanisms responsible for these side-effects remain poorly understood, increasing evidence points to a link between SGAs and adipose tissue depots of white, brown and beige adipocytes. In this review, we survey the present knowledge in this area, with a particular focus on the molecular aspects of adipocyte biology including differentiation, lipid metabolism, thermogenic function and the browning/beiging processThis work was funded by H2020 Marie Skłodowska-Curie ActionsITN-TREATMENT (Grant Agreement 721236, European Commission). We also acknowledge grants RTI2018-094052-B-100 (MICINN/FEDER, Spain), S2017/BMD-3684 MOIR2-CM (Comunidad de Madrid, Spain) and CIBERdem (ISCIII, Spain)

SIRT1 enhances glucose tolerance by potentiating brown adipose tissue function

This is an open access article under the CC BY-NC-ND license.-- et al.[Objective]: SIRT1 has been proposed to be a key signaling node linking changes in energy metabolism to transcriptional adaptations. Although SIRT1 overexpression is protective against diverse metabolic complications, especially in response to high-fat diets, studies aiming to understand the etiology of such benefits are scarce. Here, we aimed to identify the key tissues and mechanisms implicated in the beneficial effects of SIRT1 on glucose homeostasis. [Methods]: We have used a mouse model of moderate SIRT1 overexpression, under the control of its natural promoter, to evaluate glucose homeostasis and thoroughly characterize how different tissues could influence insulin sensitivity. [Results]: Mice with moderate overexpression of SIRT1 exhibit better glucose tolerance and insulin sensitivity even on a low fat diet. Euglycemic-hyperinsulinemic clamps and in-depth tissue analyses revealed that enhanced insulin sensitivity was achieved through a higher brown adipose tissue activity and was fully reversed by housing the mice at thermoneutrality. SIRT1 did not influence brown adipocyte differentiation, but dramatically enhanced the metabolic transcriptional responses to β3-adrenergic stimuli in differentiated adipocytes. [Conclusions]: Our work demonstrates that SIRT1 improves glucose homeostasis by enhancing BAT function. This is not consequent to an alteration in the brown adipocyte differentiation process, but as a result of potentiating the response to β3-adrenergic stimuli.M.S. is funded by the CNIO and by grants from the MICINN (SAF), the Regional Government of Madrid, the European Research Council (CANCER&AGING; LS1, ERC-2008-AdG), the Botín Foundation, the Ramón Areces Foundation, and the AXA Foundation. P.J.F.M. is funded by the AECC. A.M.V. is funded by the following grant support: SAF2012-33283 (MINECO, Spain), Comunidad de Madrid S2010/BMD-2423, EFSD and Amylin Paul Langerhans Grant and Centro de Investigación Biomédica en Red de Diabetes y Enfermedades Metabólicas Asociadas (CIBERDEM, ISCIII, Barcelona, Spain). P.M.G.R. is funded by the following grant support: BFU2011-24679 (MINECO, Spain) and he is a recipient of a Ramon y Cajal contract: RYC-2009-05158(MINECO, Spain).Peer Reviewe

Developmental switch from prolonged insulin action to increased insulin sensitivity in protein tyrosine phosphatase 1B-deficient hepatocytes

15 pages, 10 figures.Protein tyrosine phosphatase 1B (PTP1B) is a negative regulator of insulin signaling and a therapeutic target for type 2 diabetes. The purpose of this study was to evaluate the differences in insulin sensitivity between neonate and adult hepatocytes lacking PTP1B. Immortalized neonatal hepatocytes and primary neonatal and adult hepatocytes have been generated from PTP1B(-/-) and wild-type mice. PTP1B deficiency in immortalized neonatal hepatocytes prolonged insulin-induced tyrosine phosphorylation of the insulin receptor (IR) and IR substrates (IRS) -1, -2 compared with wild-type control cells. Endogenous IR and IRS-2 were down-regulated, whereas IRS-1 was up-regulated in PTP1B(-/-) neonatal hepatocytes and livers of PTP1B(-/-) neonates. Insulin-induced activation of phosphatidylinositol 3-kinase/Akt pathway was prolonged in PTP1B(-/-) immortalized neonatal hepatocytes. However, insulin sensitivity was comparable to wild-type hepatocytes. Rescue of PTP1B in deficient cells suppressed the prolonged insulin signaling, whereas RNA interference in wild-type cells promoted prolonged signaling. In primary neonatal PTP1B(-/-) hepatocytes, insulin prolonged the inhibition of gluconeogenic mRNAs, but the sensitivity to this inhibition was similar to wild-type cells. By contrast, in adult PTP1B-deficient livers, p85alpha was down-regulated compared with the wild type. Moreover, primary hepatocytes from adult PTP1B(-/-) mice displayed enhanced Akt phosphorylation and a more pronounced inhibition of gluconeogenic mRNAs than wild-type cells. Hepatic insulin sensitivity due to PTP1B deficiency is acquired through postnatal development. Thus, changes in IR and IRS-2 expression and in the balance between regulatory and catalytic subunits of phosphatidylinositol 3-kinase are necessary to achieve insulin sensitization in adult PTP1B(-/-) hepatocytes.This work was supported by Grant BFU 2005-01615 (to A.M.V.) and Grant SAF 2004-5545 (to M.B.) from Ministerio de Educación y Ciencia (Spain), Grant CAM/GR/SAL/0384/2004 (to A.M.V.) from Comunidad de Madrid (Spain), and Red de Grupos de Diabetes Mellitus Grant G03/212, Instituto Carlos III (Spain). A.G.-R. was supported by Grant FPU (Ministerio de Educación, Spain). O.E. was supported by Juan de la Cierva programe (Ministerio de Educación, Spain).Peer reviewe

PTP1B deficiency increases glucose uptake in neonatal hepatocytes: involvement of IRA/GLUT2 complexes

11 pages, 5 figures, 1 table.The contribution of the liver to glucose utilization is essential to maintain glucose homeostasis. Previous data from protein tyrosine phosphatase (PTP) 1B-deficient mice demonstrated that the liver is a major site for PTP1B action in the periphery. In this study, we have investigated the consequences of PTP1B deficiency in glucose uptake in hepatocytes from neonatal and adult mice. The lack of PTP1B increased basal glucose uptake in hepatocytes from neonatal (3-5 days old) but not adult (10-12 wk old) mice. This occurs without changes in hexokinase, glucokinase, and glucose 6-phosphatase enzymatic activities. By contrast, the glucose transporter GLUT2 was upregulated at the protein level in neonatal hepatocytes and livers from PTP1B-deficient neonates. These results were accompanied by a significant increase in the net free intrahepatic glucose levels in the livers of PTP1B(-/-) neonates. The association between GLUT2 and insulin receptor (IR) A isoform was increased in PTP1B(-/-) neonatal hepatocytes compared with the wild-type. Indeed, PTP1B deficiency in neonatal hepatocytes shifted the ratio of isoforms A and B of the IR by increasing the amount of IRA and decreasing IRB. Moreover, overexpression of IRA in PTP1B(-/-) neonatal hepatocytes increased the amount of IRA/GLUT2 complexes. Conversely, hepatocytes from adult mice only expressed IRB. Since IRA plays a direct role in the regulation of glucose uptake in neonatal hepatocytes through its specific association with GLUT2, we propose the increase in IRA/GLUT2 complexes due to PTP1B deficiency as the molecular mechanism of the increased glucose uptake in the neonatal stage.This work was supported by grants BFU2005-1615 (A. M. Valverde), SAF 2004-5545 (M. Benito), and CIBER de Diabetes y Enfermedades Metabólicas Asociadas (ISCIII, Spain). A. González-Rodríguez and C. Nevado were recipients of fellowships from Ministerio de Educación y Ciencia (Spain).Peer reviewe

Increased oxidative stress and apoptosis in the hypothalamus of diabetic male mice in the insulin receptor substrate-2 knockout model

Insulin receptor substrate-2-deficient (IRS2-/-) mice are considered a good model to study the development of diabetes because IRS proteins mediate the pleiotropic effects of insulin-like growth factor-I (IGF-I) and insulin on metabolism, mitogenesis and cell survival. The hypothalamus might play a key role in the early onset of diabetes, owing to its involvement in the control of glucose homeostasis and energy balance. Because some inflammatory markers are elevated in the hypothalamus of diabetic IRS2-/- mice, our aim was to analyze whether the diabetes associated with the absence of IRS2 results in hypothalamic injury and to analyze the intracellular mechanisms involved. Only diabetic IRS2-/- mice showed increased cell death and activation of caspase-8 and -3 in the hypothalamus. Regulators of apoptosis such as FADD, Bcl-2, Bcl-xL and p53 were also increased, whereas p-IκB and c-FLIPL were decreased. This was accompanied by increased levels of Nox-4 and catalase, enzymes involved in oxidative stress. In summary, the hypothalamus of diabetic IRS2-/- mice showed an increase in oxidative stress and inflammatory markers that finally resulted in cell death via substantial activation of the extrinsic apoptotic pathway. Conversely, nondiabetic IRS2-/- mice did not show cell death in the hypothalamus, possibly owing to an increase in the levels of circulating IGF-I and in the enhanced hypothalamic IGF-IR phosphorylation that would lead to the stimulation of survival pathways. In conclusion, diabetes in IRS2-deficient male mice is associated with increased oxidative stress and apoptosis in the hypothalamusThis work was supported by the Ministerio de Ciencia e Innovación [BFU2011- 27492 and BFU2014-51836-C2-2-R to J.A.C.; and SAF2012-33283 to A.M.V.]; Fondo de Investigación Sanitaria [PI1302195 to J.A.]; Centro de Investigación Biomédica en Red de Fisiopatologı́a de Obesidad y Nutrición (CIBEROBN); and Centro de Investigación Biomédica en Red Diabetes y Enfermedades asociadas (CIBERDEM), Instituto de Salud Carlos III, and Fundación de Endocrinologı́a y Nutrición

Defective liver glycogen autophagy related to hyperinsulinemia in intrauterine growth-restricted newborn wistar rats

Maternal malnutrition plays a critical role in the developmental programming of later metabolic diseases susceptibility in the offspring, such as obesity and type 2 diabetes. Because the liver is the major organ that produces and supplies blood glucose, we aimed at defining the potential role of liver glycogen autophagy in the programming of glucose metabolism disturbances. To this end, newborns were obtained from pregnant Wistar rats fed ad libitum with a standard diet or 65% food-restricted during the last week of gestation. We found that newborns from undernourished mothers showed markedly high basal insulin levels whereas those of glucagon were decreased. This unbalance led to activation of the mTORC1 pathway and inhibition of hepatic autophagy compromising the adequate handling of glycogen in the very early hours of extrauterine life. Restoration of autophagy with rapamycin but not with glucagon, indicated no defect in autophagy machinery per se, but in signals triggered by glucagon. Taken together, these results support the notion that hyperinsulinemia is an important mechanism by which mobilization of liver glycogen by autophagy is defective in food-restricted animals. This early alteration in the hormonal control of liver glycogen autophagy may influence the risk of developing metabolic diseases later in life.This work was supported by MINECO (BFU2016-77931-R), CIBERdem (ISCIII, Spain) and MOIR-2 S2017-BMD-3684 (CAM

Increased hypothalamic anti‐inflammatory mediators in non‐diabetic insulin receptor substrate 2‐deficient mice

© 2021 by the authors.Insulin receptor substrate (IRS) 2 is a key mediator of insulin signaling and IRS-2 knockout (IRS2−/−) mice are a preclinical model to study the development of diabetes, as they develop peripheral insulin resistance and beta-cell failure. The differential inflammatory profile and insulin signaling in the hypothalamus of non-diabetic (ND) and diabetic (D) IRS2−/− mice might be implicated in the onset of diabetes. Because the lipid profile is related to changes in inflammation and insulin sensitivity, we analyzed whether ND IRS2−/− mice presented a different hypothalamic fatty acid metabolism and lipid pattern than D IRS2−/− mice and the relationship with inflammation and markers of insulin sensitivity. ND IRS2−/− mice showed elevated hypothalamic anti-inflammatory cytokines, while D IRS2−/− mice displayed a proinflammatory profile. The increased activity of enzymes related to the pentose-phosphate route and lipid anabolism and elevated polyunsaturated fatty acid levels were found in the hypothalamus of ND IRS2−/− mice. Conversely, D IRS2−/− mice have no changes in fatty acid composition, but hypothalamic energy balance and markers related to anti-inflammatory and insulin-sensitizing properties were reduced. The data suggest that the concurrence of an anti-inflammatory profile, increased insulin sensitivity and polyunsaturated fatty acids content in the hypothalamus may slow down or delay the onset of diabetes.This work was supported by the Spanish Ministry of Science and Innovation with the help of European FEDER funding (grant numbers FIS PI19/00166, BFU 2017-82565-C2-1-R, and RTI2018-094052-B-100), Comunidad de Madrid, Spain (S2017/BMD-3684) and the Network Center for Biomedical Research on Obesity and Nutrition (CIBEROBN) and Diabetes (CIBERDEM) Instituto Carlos III. S.C. was supported by CIBEROBN and A.G.M. by Fundación para la Investigación Biomédica Hospital Infantil Universitario Niño Jesús