Coactivator condensation drives cardiovascular cell lineage specification.

During development, cells make switch-like decisions to activate new gene programs specifying cell lineage. The mechanisms underlying these decisive choices remain unclear. Here, we show that the cardiovascular transcriptional coactivator myocardin (MYOCD) activates cell identity genes by concentration-dependent and switch-like formation of transcriptional condensates. MYOCD forms such condensates and activates cell identity genes at critical concentration thresholds achieved during smooth muscle cell and cardiomyocyte differentiation. The carboxyl-terminal disordered region of MYOCD is necessary and sufficient for condensate formation. Disrupting this region's ability to form condensates disrupts gene activation and smooth muscle cell reprogramming. Rescuing condensate formation by replacing this region with disordered regions from functionally unrelated proteins rescues gene activation and smooth muscle cell reprogramming. Our findings demonstrate that MYOCD condensate formation is required for gene activation during cardiovascular differentiation. We propose that the formation of transcriptional condensates at critical concentrations of cell type-specific regulators provides a molecular switch underlying the activation of key cell identity genes during development.

Fungal microbiota isolated from native stingless bee species inhibited pathogens of Apis mellifera.

Social bees can establish interactions with microorganisms to keep their colonies free of pathogens and parasites by developing different protection strategies. We explored the fungal microbiota isolated from three species of stingless bees, Tetragonisca fiebrigi, Plebeias sp., and Scaptotrigona jujuyensis, and its potential ability to suppress pathogenic microorganisms of A. mellifera, namely Paenibacillus larvae, Ascosphaera apis and Aspergillus flavus, which were tested and evaluated. Six filamentous fungal strains, Trametes hirsuta, Alternaria alternata, Curvularia spicifera, Skeletocutis sp., Alternaria tenuissima, Monascus spp., as well as the yeast Wickerhamomyces anomalus, were selected for trials and isolated from the heads of foraging bees. The fungal strains were identified by macroscopic and microscopic taxonomic characteristics and by sequencing of the ITS1-5.8S-ITS2 region of ribosomal DNA. All fungal strains inhibited these pathogens of A. mellifera. We also evaluated the effect of the secondary metabolites extracted with and without ethanol. Both metabolites showed antimicrobial properties, and our results suggest that fungi isolated from stingless bees produce bioactive compounds with antibacterial and antifungal effects that could be used to treat Apis mellifera colony diseases and maintain colony health.

Functional partitioning of transcriptional regulators by patterned charge blocks.

Components of transcriptional machinery are selectively partitioned into specific condensates, often mediated by protein disorder, yet we know little about how this specificity is achieved. Here, we show that condensates composed of the intrinsically disordered region (IDR) of MED1 selectively partition RNA polymerase II together with its positive allosteric regulators while excluding negative regulators. This selective compartmentalization is sufficient to activate transcription and is required for gene activation during a cell-state transition. The IDRs of partitioned proteins are necessary and sufficient for selective compartmentalization and require alternating blocks of charged amino acids. Disrupting this charge pattern prevents partitioning, whereas adding the pattern to proteins promotes partitioning with functional consequences for gene activation. IDRs with similar patterned charge blocks show similar partitioning and function. These findings demonstrate that disorder-mediated interactions can selectively compartmentalize specific functionally related proteins from a complex mixture of biomolecules, leading to regulation of a biochemical pathway.

[Integrated Care Protocol: Hypertension]. / Protocolo de Atención Integral: hipertensión arterial sistémica.

Background: Hypertension is the most common cardiovascular risk factor that is responsible for complications such as cerebrovascular events, heart failure, acute myocardial infarction, kidney failure, arrhythmias and blindness. About 30% of the adult population older than 20 years is a carrier. 40% of carriers are unaware of suffering from it since its onset is generally asymptomatic. Unfortunately, of those who are already known to be hypertensive, only half take drug treatment and of these, only half achieve control figures (<14/90 mmHg). For several decades it has not been possible to forcefully modify the natural history of this disease despite the advancement of therapeutic drugs. The Mexican Institute of Social Security launches the initiative of the Integrated Care Protocols (PAI) of the main diseases. This protocol shows how the three levels of medical care are concatenated, the role of each of the members of the multidisciplinary team for medical care, including: doctor, nurse, social work, psychologist, nutritionist, among others and, to patient sharing. The main changes in diagnostic criteria, in-office and out-of-office blood pressure measurement, drug therapy (monotherapy, dual therapy and triple therapy) and non-drug therapy, and follow-up are presented. The diagnostic-therapeutic approach using algorithm as well as the diagnostic approach to secondary hypertension and special forms of hypertension such as in pregnancy, hypertensive crisis, hypertension in the elderly, ischemic or nephropathy patients.

Introducción: la hipertensión arterial sistémica (HAS) es el factor de riesgo cardiovascular más común y es responsable de complicaciones como evento cerebrovascular, insuficiencia cardiaca, infarto agudo de miocardio, insuficiencia renal, arritmias y ceguera. Alrededor del 30% de la población adulta mayor de 20 años es portadora. El 40% de los portadores ignoran padecerla ya que su inicio generalmente es asintomático. Desafortunadamente de los que ya se saben hipertensos solo la mitad toma tratamiento farmacológico y de estos, tan solo la mitad logra cifras de control (< 140/90 mmHg). Durante varias décadas no se ha logrado de forma contundente modificar la historia natural de esta enfermedad pese al avance fármaco terapéutico. El Instituto Mexicano del Seguro Social, lanza la iniciativa de los Protocolos de Atención Integral (PAI) de las principales enfermedades. En el presente protocolo se muestra cómo se concatenan los tres niveles de atención médica, el papel de cada uno de los integrantes del equipo multidisciplinario para la atención médica, incluyendo: médico, enfermera, trabajo social, psicólogo, nutricionista, entre otros y, la coparticipación del paciente. Se presentan los principales cambios en criterios diagnósticos, medición de la presión arterial dentro y fuera de consultorio, terapéutica farmacológica (monoterapia, terapia dual y terapia triple), no farmacológica y seguimiento. El Abordaje diagnóstico-terapéutico usando algoritmos, así como también el abordaje diagnóstico de la hipertensión secundaria y formas especiales de hipertensión tales como en el embarazo, crisis hipertensivas, hipertensión en el adulto mayor, pacientes isquémicos o con nefropatía.

Suicidal behaviour in adolescents: Educational interventions in Mexico.

Suicide in adolescents constitutes a public health problem throughout the world. The objective of this study was to identify the prevalence of suicidal behaviour in a public middle school in Mexico and to implement appropriate educational interventions in the school and community contexts. Our work took place from September 2017 to July 2018. We conducted a quasi-experimental, mixed-methodology study with 12-year-old students in first year of middle school (n = 29), using an educational intervention approach within the frame of the Life Skills Education methodology. We included family members and academic staff in the study with the view of sensitising them to suicidal behaviour. At the community level, we worked with the adolescent and adult populations to form 'gatekeepers' (guardians). We administered a questionnaire on psychosocial indicators of depression and suicide risk to 383 students in their first-to-third years of middle school. Other questionnaires were applied, and life skills focus groups (FGs) were organised with the educational intervention participants. The questionnaires addressed suicidal behaviour in adolescents, alcohol consumption, life skills and prosociality. Prevalence of attempted suicide cases came to 14.1% (95 CI% 10.7-17.9), the average age of those who reported having hurt themselves with the purpose of taking their lives was 12.9 years, 75% of those who had attempted suicide were female and 64.8% had consumed alcohol. The educational intervention with students achieved a statistically significant increase in the life skills of participants, specifically as regards self-awareness and overall scores. The family members in the FGs developed greater awareness of suicidal behaviour, and the adolescents engaged at the community level significantly broadened (p < .05) their knowledge of depression. In developing countries such as Mexico, it is essential not only to increase the number of interventions for preventing suicidal behaviour in adolescents, but also to improve instruments for measuring the extent of the problem.

Extraparenchymal neurocysticercosis: Demographic, clinicoradiological, and inflammatory features.

BACKGROUND: Extraparenchymal neurocysticercosis (ExPNCC), an infection caused by Taenia solium cysticerci that mainly occurs in the ventricular compartment (Ve) or the basal subarachnoid space (SAb), is more severe but less frequent and much less studied than parenchymal neurocysticercosis (ParNCC). Demographic, clinical, radiological, and lumbar cerebrospinal fluid features of patients affected by ExPNCC are herein described and compared with those of ParNCC patients. METHODOLOGY AND PRINCIPAL FINDINGS: 429 patients with a confirmed diagnosis of neurocysticercosis, attending the Instituto Nacional de Neurología y Neurocirugía, a tertiary reference center in Mexico City, from 2000 through 2014, were included. Demographic information, signs and symptoms, radiological patterns, and lumbar cerebrospinal fluid (CSF) laboratory values were retrieved from medical records for all patients. Data were statistically analyzed to assess potential differences depending on cyst location and to determine the effects of age and sex on the disease presentation. In total, 238 ExPNCC and 191 ParNCC patients were included. With respect to parenchymal cysts, extraparenchymal parasites were diagnosed at an older age (P = 0.002), chiefly caused intracranial hypertension (P < 0.0001), were more frequently multiple and vesicular (P < 0.0001), and CSF from these patients showed higher protein concentration and cell count (P < 0.0001). SAb patients were diagnosed at an older age than Ve patients, and showed more frequently seizures, vesicular cysticerci, and higher CSF cellularity. Gender and age modulated some traits of the disease. CONCLUSIONS: This study evidenced clear clinical, radiological, and inflammatory differences between ExPNCC and ParNCC, and between SAb and Ve patients, and demonstrated that parasite location determines different pathological entities.

Determination of Glucose Utilization Rates in Cultured Astrocytes and Neurons with [14C]deoxyglucose: Progress, Pitfalls, and Discovery of Intracellular Glucose Compartmentation.

2-Deoxy-D-[14C]glucose ([14C]DG) is commonly used to determine local glucose utilization rates (CMRglc) in living brain and to estimate CMRglc in cultured brain cells as rates of [14C]DG phosphorylation. Phosphorylation rates of [14C]DG and its metabolizable fluorescent analog, 2-(N-(7-nitrobenz-2-oxa-1,3-diazol-4-yl)amino)-2-deoxyglucose (2-NBDG), however, do not take into account differences in the kinetics of transport and metabolism of [14C]DG or 2-NBDG and glucose in neuronal and astrocytic cells in cultures or in single cells in brain tissue, and conclusions drawn from these data may, therefore, not be correct. As a first step toward the goal of quantitative determination of CMRglc in astrocytes and neurons in cultures, the steady-state intracellular-to-extracellular concentration ratios (distribution spaces) for glucose and [14C]DG were determined in cultured striatal neurons and astrocytes as functions of extracellular glucose concentration. Unexpectedly, the glucose distribution spaces rose during extreme hypoglycemia, exceeding 1.0 in astrocytes, whereas the [14C]DG distribution space fell at the lowest glucose levels. Calculated CMRglc was greatly overestimated in hypoglycemic and normoglycemic cells because the intracellular glucose concentrations were too high. Determination of the distribution space for [14C]glucose revealed compartmentation of intracellular glucose in astrocytes, and probably, also in neurons. A smaller metabolic pool is readily accessible to hexokinase and communicates with extracellular glucose, whereas the larger pool is sequestered from hexokinase activity. A new experimental approach using double-labeled assays with DG and glucose is suggested to avoid the limitations imposed by glucose compartmentation on metabolic assays.

Organ Distribution of 13N Following Intravenous Injection of [13N]Ammonia into Portacaval-Shunted Rats.

Ammonia is neurotoxic, and chronic hyperammonemia is thought to be a major contributing factor to hepatic encephalopathy in patients with liver disease. Portacaval shunting of rats is used as an animal model to study the detrimental metabolic effects of elevated ammonia levels on body tissues, particularly brain and testes that are deleteriously targeted by high blood ammonia. In normal adult rats, the initial uptake of label (expressed as relative concentration) in these organs was relatively low following a bolus intravenous injection of [13N]ammonia compared with lungs, kidneys, liver, and some other organs. The objective of the present study was to determine the distribution of label following intravenous administration of [13N]ammonia among 14 organs in portacaval-shunted rats at 12 weeks after shunt construction. At an early time point (12 s) following administration of [13N]ammonia the relative concentration of label was highest in lung with lower, but still appreciable relative concentrations in kidney and heart. Clearance of 13N from blood and kidney tended to be slower in portacaval-shunted rats versus normal rats during the 2-10 min interval after the injection. At later times post injection, brain and testes tended to have higher-than-normal 13N levels, whereas many other tissues had similar levels in both groups. Thus, reduced removal of ammonia from circulating blood by the liver diverts more ammonia to extrahepatic tissues, including brain and testes, and alters the nitrogen homeostasis in these tissues. These results emphasize the importance of treatment paradigms designed to reduce blood ammonia levels in patients with liver disease.

Aerobic glycolysis during brain activation: adrenergic regulation and influence of norepinephrine on astrocytic metabolism.

Aerobic glycolysis occurs during brain activation and is characterized by preferential up-regulation of glucose utilization compared with oxygen consumption even though oxygen level and delivery are adequate. Aerobic glycolysis is a widespread phenomenon that underlies energetics of diverse brain activities, such as alerting, sensory processing, cognition, memory, and pathophysiological conditions, but specific cellular functions fulfilled by aerobic glycolysis are poorly understood. Evaluation of evidence derived from different disciplines reveals that aerobic glycolysis is a complex, regulated phenomenon that is prevented by propranolol, a non-specific ß-adrenoceptor antagonist. The metabolic pathways that contribute to excess utilization of glucose compared with oxygen include glycolysis, the pentose phosphate shunt pathway, the malate-aspartate shuttle, and astrocytic glycogen turnover. Increased lactate production by unidentified cells, and lactate dispersal from activated cells and lactate release from the brain, both facilitated by astrocytes, are major factors underlying aerobic glycolysis in subjects with low blood lactate levels. Astrocyte-neuron lactate shuttling with local oxidation is minor. Blockade of aerobic glycolysis by propranolol implicates adrenergic regulatory processes including adrenal release of epinephrine, signaling to brain via the vagus nerve, and increased norepinephrine release from the locus coeruleus. Norepinephrine has a powerful influence on astrocytic metabolism and glycogen turnover that can stimulate carbohydrate utilization more than oxygen consumption, whereas ß-receptor blockade 're-balances' the stoichiometry of oxygen-glucose or -carbohydrate metabolism by suppressing glucose and glycogen utilization more than oxygen consumption. This conceptual framework may be helpful for design of future studies to elucidate functional roles of preferential non-oxidative glucose utilization and glycogen turnover during brain activation. Aerobic glycolysis, the preferential up-regulation of glucose utilization (CMRglc ) compared with oxygen consumption (CMRO2 ) during brain activation, is blocked by propranolol. Epinephrine release from the adrenal gland stimulates vagus nerve signaling to the locus coeruleus, enhancing norepinephrine release in the brain, and regulation of astrocytic and neuronal metabolism to stimulate CMRglc more than CMRO2 . Propranolol suppresses CMRglc more than CMRO2 .

Biochemical, Metabolic, and Behavioral Characteristics of Immature Chronic Hyperphenylalanemic Rats.

Phenylketonuria and hyperphenylalanemia are inborn errors in metabolism of phenylalanine arising from defects in steps to convert phenylalanine to tyrosine. Phe accumulation causes severe mental retardation that can be prevented by timely identification of affected individuals and their placement on a Phe-restricted diet. In spite of many studies in patients and animal models, the basis for acquisition of mental retardation during the critical period of brain development is not adequately understood. All animal models for human disease have advantages and limitations, and characteristics common to different models are most likely to correspond to the disorder. This study established similar levels of Phe exposure in developing rats between 3 and 16 days of age using three models to produce chronic hyperphenylalanemia, and identified changes in brain amino acid levels common to all models that persist for ~16 h of each day. In a representative model, local rates of glucose utilization (CMRglc) were determined at 25-27 days of age, and only selective changes that appeared to depend on Phe exposure were observed. CMRglc was reduced in frontal cortex and thalamus and increased in hippocampus and globus pallidus. Behavioral testing to evaluate neuromuscular competence revealed poor performance in chronically-hyperphenylalanemic rats that persisted for at least 3 weeks after cessation of Phe injections and did not occur with mild or acute hyperphenylalanemia. Thus, the abnormal amino acid environment, including hyperglycinemia, in developing rat brain is associated with selective regional changes in glucose utilization and behavioral abnormalities that are not readily reversed after they are acquired.

Retinal nerve fiber layer and macular thickness in patients with schizophrenia: Influence of recent illness episodes.

Optical coherence tomography (OCT) has been recently used to investigate neuropsychiatric disorders. We aimed to study retinal OCT measures of patients with schizophrenia with respect to healthy controls, and to evaluate possible differences between recent illness episode (RIE) and non-recent illness episode (NRIE) patients. Thirty schizophrenia patients were classified as RIE (n=10) or NRIE (n=20), and compared with 30 matched controls. Statistical analyses included linear mixed-effects models to study the association between OCT measures and group membership. Multivariate models were used to control for potential confounders. In the adjusted linear mixed-effects regression model, patients had a significantly thinner retinal nerve fiber layer (RNFL) in overall measurements, and in the nasal, superior and inferior quadrants. Macular inner ring thickness and macular volume were also significantly smaller in patients than controls. Compared with controls, in the adjusted model only NRIE (but not RIE) patients had significantly reduced RNFL overall measures, superior RNFL, nasal RNFL, macular volume, and macular inner ring thickness. No significant correlation was found between illness duration and retinal measurements after controlling for age. In conclusion, retinal parameters observed using OCT in schizophrenia patients could be related to clinical status and merit attention as potential state biomarkers of the disorder.

Contributions of glycogen to astrocytic energetics during brain activation.

Glycogen is the major store of glucose in brain and is mainly in astrocytes. Brain glycogen levels in unstimulated, carefully-handled rats are 10-12 µmol/g, and assuming that astrocytes account for half the brain mass, astrocytic glycogen content is twice as high. Glycogen turnover is slow under basal conditions, but it is mobilized during activation. There is no net increase in incorporation of label from glucose during activation, whereas label release from pre-labeled glycogen exceeds net glycogen consumption, which increases during stronger stimuli. Because glycogen level is restored by non-oxidative metabolism, astrocytes can influence the global ratio of oxygen to glucose utilization. Compensatory increases in utilization of blood glucose during inhibition of glycogen phosphorylase are large and approximate glycogenolysis rates during sensory stimulation. In contrast, glycogenolysis rates during hypoglycemia are low due to continued glucose delivery and oxidation of endogenous substrates; rates that preserve neuronal function in the absence of glucose are also low, probably due to metabolite oxidation. Modeling studies predict that glycogenolysis maintains a high level of glucose-6-phosphate in astrocytes to maintain feedback inhibition of hexokinase, thereby diverting glucose for use by neurons. The fate of glycogen carbon in vivo is not known, but lactate efflux from brain best accounts for the major metabolic characteristics during activation of living brain. Substantial shuttling coupled with oxidation of glycogen-derived lactate is inconsistent with available evidence. Glycogen has important roles in astrocytic energetics, including glucose sparing, control of extracellular K(+) level, oxidative stress management, and memory consolidation; it is a multi-functional compound.

Retinal alterations in mild cognitive impairment and Alzheimer's disease: an optical coherence tomography study.

Retinal nerve fiber layer thickness (RNFL) measured by means of Optical Coherence Tomography (OCT) has been used as a marker not only of ophthalmologic diseases but also of neurodegenerative diseases such as Alzheimer's disease (AD) and mild cognitive impairment (MCI). The purpose of this work was to demonstrate that patients with amnestic MCI show an intermediate RNFL thickness between normality and AD, and a macular volume and thickness as well. In a cross-sectional study we consecutively recruited 18 patients with AD, 21 with MCI, and 41 healthy controls. OCT was performed in all of them to measure circumpapillary RNFL thickness in µm, as well as macular volume and thickness. In the analysis of variance we saw that RNFL was thinner in MCI patients compared with controls, and it was also thinner in AD patients compared with MCI patients and controls. With regard to the macular measurements in mm(3), MCI patients had the greatest macular volume in comparison with AD patients and controls. In turn the controls had greater macular volume than AD patients. The decreased RNFL thickness in MCI and AD patients suggests loss of retinal neurons and their axons. The increased thickness and macular volume have never been reported before in aMCI. This finding could be explained by inflammation and/or gliosis in early stages of AD. OCT could be a useful marker of AD for early detection and monitoring progression.

Rapid manifestation of reactive astrogliosis in acute hippocampal brain slices.

A flurry of studies over the past decade has shown that astrocytes play a more active role in neural function than previously recognized. Hippocampal slices prepared from young rodent pups have served as a popular model for studying the pathways by which astrocytes participate in synaptic transmission. It is, however, not known how well astrocytes tolerate traumatic injury and hypoxia, which are unavoidable when preparing acute slices. We here showed that astrocytes exhibit striking changes in expression of several receptors and structural proteins, including re-expression of the developmental marker nestin within 90 min following preparation of live vibratome slices. Moreover, immunoelectron microscopy showed a 2.7-fold loss of astrocytic processes in acute hippocampal slices prepared from glial fibrillary acidic protein-green fluorescent protein reporter mice. A sharp decrease in the number of mitochondria was also noted in acute slices, concurrently with an increase in mitochondrial size. Glycogen content decreased 3-fold upon slice preparation and did not recover despite stable recordings of field excitatory postsynaptic current. Analysis of Ca(2+) signaling showed that astrocytic responses to purine receptor and mGluR5 agonists differed in slice versus in vivo. These observations suggest that the functional properties and the fine structure of astrocytes in slices may be reflective of early stages of reactive gliosis and should be confirmed in vivo when possible.

Reduced clearance of proteins labeled with diisopropylfluorophosphate in portacaval-shunted rats.

Portacaval shunting is a model for hepatic encephalopathy that causes chronic hyperammonemia, disruption of metabolic, signaling, and neurotransmitter systems, and progressive morphological changes. Exposure of cultured cells to ammonia raises intralysosomal pH and inhibits proteolysis, and the present study tested the hypothesis that proteolytic capacity is diminished in portacaval-shunted rats. Proteins were labeled in vivo with tracer doses of diisopropylfluorophosphate (DFP) and clearance of label was assayed. This approach labeled proteins independent of protein synthesis, which is reported to be altered in shunted rats, and avoided complications arising from re-utilization of labeled amino acids that causes underestimation of degradation rate. Characterization of DFP labeling showed that protein labeling was fast, about 50% of the label was released during a 24 h interval, labeling by DFP metabolites was negligible, inhibition of brain acetylcholinesterase was not detectable, and labeling by [(3)H]- and [(14)C]DFP was equivalent. To assay degradative capacity, proteins were first labeled with [(3)H]DFP, followed by labeling with [(14)C]DFP that was given 24 or 72 h later. The (3)H/(14)C ratio in each animal was used as a relative measure of removal of (3)H-labeled proteins. (3)H/(14)C ratios were generally significantly higher in portacaval-shunted rats than in controls, consistent with reduced proteolytic capacity. Assays of amino acid incorporation into brain protein generally replicated literature reports, supporting the conclusion that protein synthesis unlikely to be markedly inhibited and amino acid recycling influences calculated protein synthesis rates in shunted rats. Therapeutic strategies to reduce ammonia level would help normalize lysosomal functions and protein and lipid turnover.

The unfolded protein response to endoplasmic reticulum stress in cultured astrocytes and rat brain during experimental diabetes.

Oxidative-nitrosative stress and inflammatory responses are associated with endoplasmic reticulum (ER) stress in diabetic retinopathy, raising the possibility that disturbances in ER protein processing may contribute to CNS dysfunction in diabetics. Upregulation of the unfolded protein response (UPR) is a homeostatic response to accumulation of abnormal proteins in the ER, and the present study tested the hypothesis that the UPR is upregulated in two models for diabetes, cultured astrocytes grown in 25mmol/L glucose for up to 4weeks and brain of streptozotocin (STZ)-treated rats with diabetes for 1-7months. Markers associated with translational blockade (phospho-eIF2α and apoptosis (CHOP), inflammatory response (inducible nitric oxide synthase, iNOS), and nitrosative stress (nuclear translocation of glyceraldehyde-3-phosphate dehydrogenase, GAPDH) were not detected in either model. Nrf2 was present in nuclei of low- and high-glucose cultures, consistent with oxidative stress. Astrocytic ATF4 expression was not altered by culture glucose concentration, whereas phospho-IRE and ATF6 levels were higher in low- compared with high-glucose cultures. The glucose-regulated chaperones, GRP78 and GRP94, were also expressed at higher levels in low- than high-glucose cultures, probably due to recurrent glucose depletion between feeding cycles. In STZ-rat cerebral cortex, ATF4 level was transiently reduced at 4months, and p-IRE levels were transiently elevated at 3months. However, GRP78 and GRP94 expression was not upregulated, and iNOS, amyloid-ß, and nuclear accumulation of GAPDH were not evident in STZ-diabetic brain. High-glucose cultured astrocytes and STZ-diabetic brain are relatively resistant to diabetes-induced ER stress, in sharp contrast with cultured retinal Müller cells and diabetic rodent retina.

Regional registration of [6-(14)C]glucose metabolism during brain activation of α-syntrophin knockout mice.

α-Syntrophin is a component of the dystrophin scaffold-protein complex that serves as an adaptor for recruitment of key proteins to the cytoplasmic side of plasma membranes. α-Syntrophin knockout (KO) causes loss of the polarized localization of aquaporin4 (AQP4) at astrocytic endfeet and interferes with water and K(+) homeostasis. During brain activation, release of ions and metabolites from endfeet is anticipated to increase perivascular fluid osmolarity, AQP4-mediated osmotic water flow from endfeet, and metabolite washout from brain. This study tests the hypothesis that reduced levels of endfoot AQP4 increase retention of [(14)C]metabolites during sensory stimulation. Conscious KO and wild-type mice were pulse-labeled with [6-(14)C] glucose during unilateral acoustic stimulation or bilateral acoustic plus whisker stimulation, and label retention was assayed by computer-assisted brain imaging or analysis of [(14)C]metabolites in extracts, respectively. High-resolution autoradiographic assays detected a 17% side-to-side difference (p < 0.05) in inferior colliculus of KO mice, not wild-type mice. However, there were no labeling differences between KO and wild-type mice for five major HPLC fractions from four dissected regions, presumably because of insufficient anatomical resolution. The results suggest a role for AQP4-mediated water flow in support of washout of metabolites, and underscore the need for greater understanding of astrocytic water and metabolite fluxes.