Acute activation of hemichannels by ethanol leads to Ca2+-dependent gliotransmitter release in astrocytes.

Multiple studies have demonstrated that acute ethanol consumption alters brain function and cognition. Nevertheless, the mechanisms underlying this phenomenon remain poorly understood. Astrocyte-mediated gliotransmission is crucial for hippocampal plasticity, and recently, the opening of hemichannels has been found to play a relevant role in this process. Hemichannels are plasma membrane channels composed of six connexins or seven pannexins, respectively, that oligomerize around a central pore. They serve as ionic and molecular exchange conduits between the cytoplasm and extracellular milieu, allowing the release of various paracrine substances, such as ATP, D-serine, and glutamate, and the entry of ions and other substances, such as Ca2+ and glucose. The persistent and exacerbated opening of hemichannels has been associated with the pathogenesis and progression of several brain diseases for at least three mechanisms. The uncontrolled activity of these channels could favor the collapse of ionic gradients and osmotic balance, the release of toxic levels of ATP or glutamate, cell swelling and plasma membrane breakdown and intracellular Ca2+ overload. Here, we evaluated whether acute ethanol exposure affects the activity of astrocyte hemichannels and the possible repercussions of this phenomenon on cytoplasmatic Ca2+ signaling and gliotransmitter release. Acute ethanol exposure triggered the rapid activation of connexin43 and pannexin1 hemichannels in astrocytes, as measured by time-lapse recordings of ethidium uptake. This heightened activity derived from a rapid rise in [Ca2+]i linked to extracellular Ca2+ influx and IP3-evoked Ca2+ release from intracellular Ca2+ stores. Relevantly, the acute ethanol-induced activation of hemichannels contributed to a persistent secondary increase in [Ca2+]i. The [Ca2+]i-dependent activation of hemichannels elicited by ethanol caused the increased release of ATP and glutamate in astroglial cultures and brain slices. Our findings offer fresh perspectives on the potential mechanisms behind acute alcohol-induced brain abnormalities and propose targeting connexin43 and pannexin1 hemichannels in astrocytes as a promising avenue to prevent deleterious consequences of alcohol consumption.

A preclinical mice model of multiple sclerosis based on the toxin-induced double-site demyelination of callosal and cerebellar fibers.

BACKGROUND: Multiple sclerosis (MS) is an irreversible progressive CNS pathology characterized by the loss of myelin (i.e. demyelination). The lack of myelin is followed by a progressive neurodegeneration triggering symptoms as diverse as fatigue, motor, locomotor and sensory impairments and/or bladder, cardiac and respiratory dysfunction. Even though there are more than fourteen approved treatments for reducing MS progression, there are still no cure for the disease. Thus, MS research is a very active field and therefore we count with different experimental animal models for studying mechanisms of demyelination and myelin repair, however, we still lack a preclinical MS model assembling demyelination mechanisms with relevant clinical-like signs. RESULTS: Here, by inducing the simultaneous demyelination of both callosal and cerebellar white matter fibers by the double-site injection of lysolecithin (LPC), we were able to reproduce CNS demyelination, astrocyte recruitment and increases levels of proinflammatory cytokines levels along with motor, locomotor and urinary impairment, as well as cardiac and respiratory dysfunction, in the same animal model. Single site LPC-injections either in corpus callosum or cerebellum only, fails in to reproduce such a complete range of MS-like signs. CONCLUSION: We here report that the double-site LPC injections treatment evoke a complex MS-like mice model. We hope that this experimental approach will help to deepen our knowledge about the mechanisms of demyelinated diseases such as MS.

Inhibition of astroglial hemichannels prevents synaptic transmission decline during spreading depression.

BACKGROUND: Spreading depression (SD) is an intriguing phenomenon characterized by massive slow brain depolarizations that affect neurons and glial cells. This phenomenon is repetitive and produces a metabolic overload that increases secondary damage. However, the mechanisms associated with the initiation and propagation of SD are unknown. Multiple lines of evidence indicate that persistent and uncontrolled opening of hemichannels could participate in the pathogenesis and progression of several neurological disorders including acute brain injuries. Here, we explored the contribution of astroglial hemichannels composed of connexin-43 (Cx43) or pannexin-1 (Panx1) to SD evoked by high-K+ stimulation in brain slices. RESULTS: Focal high-K+ stimulation rapidly evoked a wave of SD linked to increased activity of the Cx43 and Panx1 hemichannels in the brain cortex, as measured by light transmittance and dye uptake analysis, respectively. The activation of these channels occurs mainly in astrocytes but also in neurons. More importantly, the inhibition of both the Cx43 and Panx1 hemichannels completely prevented high K+-induced SD in the brain cortex. Electrophysiological recordings also revealed that Cx43 and Panx1 hemichannels critically contribute to the SD-induced decrease in synaptic transmission in the brain cortex and hippocampus. CONCLUSIONS: Targeting Cx43 and Panx1 hemichannels could serve as a new therapeutic strategy to prevent the initiation and propagation of SD in several acute brain injuries.

Acute Administration of Calafate (Berberis microphylla) Extract Induces the Expression of Thermogenic Markers and Modulates Gut Microbiota in Mice Fed a High-Fat Chow Diet.

INTRODUCTION: Obesity, characterized by excess adipose tissue, is a major public health problem worldwide. Brown adipose tissue (BAT) and beige adipose tissue participate in thermogenesis through uncoupling protein 1 (UCP1). Polyphenols including those from Calafate (a native polyphenol-rich Patagonian berry), are considered as potential anti-obesity compounds due to their pro-thermogenic characteristics. However, polyphenols are mainly metabolized by the gut microbiota (GM) that may influence their bioactivity and bioavailability. The aim of this study was to determine the impact of dietary administration with a Calafate polyphenol-rich extract on thermogenic activity of BAT and beige adipose tissue and GM composition. METHODS: Eight-week-old C57BL6 mice (n = 30) were divided into 4 groups to receive for 24 weeks a control diet (C), a high-fat diet alone (HF), or high-fat diet supplemented with Calafate extract (HFC) or the same high-fat diet supplemented with Calafate extract but treated with antibiotics (HFCAB) from week 19-20. Administration with Calafate extract (50 mg/kg per day) was carried out for 3 weeks from week 21-23 in the HFC and HFCAB groups. After euthanasia, gene expression of thermogenic markers was analyzed in BAT and inguinal white adipose tissue (iWAT). Transmission electron microscopy was performed to assess mitochondrial morphology and cristae density in BAT. GM diversity and composition were characterized by deep sequencing with the MiSeq Illumina platform. RESULTS: Calafate extract administration had no effect on weight gain in mice fed a high-fat diet. However, it prevented alterations in mitochondrial cristae induced by HFD and increased Dio2 expression in BAT and iWAT. The intervention also influenced the GM composition, preventing changes in specific bacterial taxa induced by the high-fat diet. However, the antibiotic treatment prevented in part these effects, suggesting the implications of GM. CONCLUSION: These results suggest that the acute administration of a Calafate extract modulates the expression of thermogenic markers, prevents alterations in mitochondrial cristae and intestinal microbiota in preclinical models. The study highlights the complex interaction between polyphenols, thermogenesis, and the GM, providing valuable insights into their potential roles in the treatment of obesity-related metabolic diseases.

Activation of Pannexin-1 channels causes cell dysfunction and damage in mesangial cells derived from angiotensin II-exposed mice.

Chronic kidney disease (CKD) is a prevalent health concern associated with various pathological conditions, including hypertensive nephropathy. Mesangial cells are crucial in maintaining glomerular function, yet their involvement in CKD pathogenesis remains poorly understood. Recent evidence indicates that overactivation of Pannexin-1 (Panx1) channels could contribute to the pathogenesis and progression of various diseases. Although Panx1 is expressed in the kidney, its contribution to the dysfunction of renal cells during pathological conditions remains to be elucidated. This study aimed to investigate the impact of Panx1 channels on mesangial cell function in the context of hypertensive nephropathy. Using an Ang II-infused mouse model and primary mesangial cell cultures, we demonstrated that in vivo exposure to Ang II sensitizes cultured mesangial cells to show increased alterations when they are subjected to subsequent in vitro exposure to Ang II. Particularly, mesangial cell cultures treated with Ang II showed elevated activity of Panx1 channels and increased release of ATP. The latter was associated with enhanced basal intracellular Ca2+ ([Ca2+]i) and increased ATP-mediated [Ca2+]i responses. These effects were accompanied by increased lipid peroxidation and reduced cell viability. Crucially, all the adverse impacts evoked by Ang II were prevented by the blockade of Panx1 channels, underscoring their critical role in mediating cellular dysfunction in mesangial cells. By elucidating the mechanisms by which Ang II negatively impacts mesangial cell function, this study provides valuable insights into the pathogenesis of renal damage in hypertensive nephropathy.

Cx43 hemichannels and panx1 channels contribute to ethanol-induced astrocyte dysfunction and damage.

BACKGROUND: Alcohol, a widely abused drug, significantly diminishes life quality, causing chronic diseases and psychiatric issues, with severe health, societal, and economic repercussions. Previously, we demonstrated that non-voluntary alcohol consumption increases the opening of Cx43 hemichannels and Panx1 channels in astrocytes from adolescent rats. However, whether ethanol directly affects astroglial hemichannels and, if so, how this impacts the function and survival of astrocytes remains to be elucidated. RESULTS: Clinically relevant concentrations of ethanol boost the opening of Cx43 hemichannels and Panx1 channels in mouse cortical astrocytes, resulting in the release of ATP and glutamate. The activation of these large-pore channels is dependent on Toll-like receptor 4, P2X7 receptors, IL-1ß and TNF-α signaling, p38 mitogen-activated protein kinase, and inducible nitric oxide (NO) synthase. Notably, the ethanol-induced opening of Cx43 hemichannels and Panx1 channels leads to alterations in cytokine secretion, NO production, gliotransmitter release, and astrocyte reactivity, ultimately impacting survival. CONCLUSION: Our study reveals a new mechanism by which ethanol impairs astrocyte function, involving the sequential stimulation of inflammatory pathways that further increase the opening of Cx43 hemichannels and Panx1 channels. We hypothesize that targeting astroglial hemichannels could be a promising pharmacological approach to preserve astrocyte function and synaptic plasticity during the progression of various alcohol use disorders.

Genotype analysis to clarify RhD variants in discrepant samples of Chilean population.

Introduction: The D antigen variants are classified as weak, partial, and extremely weak (DEL) and can be differentiated using molecular tests. In Chile, the laboratories of local blood centers do not identify variants of the D antigen, referring them for study to the Reference Laboratory of the Public Health Institute of Chile. So, our aim was to talk about the results of the molecular analysis of variants of the D antigen in samples that had different results in the serological classification. Methods: In the D antigen classification of the Rh system, 479 samples with serological discrepant results were sent for molecular analysis. The Rh phenotype was performed with monoclonal anti-C, anti-c, anti-E, and anti-e antisera by direct agglutination. To find the D antigen, researchers used direct agglutination with monoclonal antisera and indirect antiglobulin testing with the column (gel) agglutination method. Molecular analysis was performed with a polymerase chain reaction with sequence-specific primers (SSP-PCR) and sequencing. Results and discussion: The presence of D antigen variants was confirmed in 332 samples (69.3%), with an initial discrepancy in serological classification. In this group of discrepant samples, the frequency of weak RhD variants was 66% (219/332), that of extremely weak RhD was 28% (93/332), and that of partial RhD was 6% (20/332). The weak variants type 2 (27.4%), type 3 (8.4%), type 48 (8.4%), and type 1 (8.1%) were the next most prevalent variants after RHD*DEL43 (28%). The ccEe (R2r) phenotype was the most frequently detected (38.4%) and is present in 87% of the RHD*DEL43 samples. The E antigen is associated with the presence of this variant. Our analyses give the first description of D antigen variants in Chile. The most common variants are DEL type (RHD*DEL43) and weak (weak type 2), which are linked to the ccDEe (R2r) phenotype. These findings allow us to characterize the variants of the D antigen in Chile and, according to the obtained data, to design strategies for the management of donors, patients, and pregnant women.

SARS-CoV-2 spike protein S1 activates Cx43 hemichannels and disturbs intracellular Ca2+ dynamics.

BACKGROUND: Severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2) causes the ongoing coronavirus disease 2019 (COVID-19). An aspect of high uncertainty is whether the SARS-CoV-2 per se or the systemic inflammation induced by viral infection directly affects cellular function and survival in different tissues. It has been postulated that tissue dysfunction and damage observed in COVID-19 patients may rely on the direct effects of SARS-CoV-2 viral proteins. Previous evidence indicates that the human immunodeficiency virus and its envelope protein gp120 increase the activity of connexin 43 (Cx43) hemichannels with negative repercussions for cellular function and survival. Here, we evaluated whether the spike protein S1 of SARS-CoV-2 could impact the activity of Cx43 hemichannels. RESULTS: We found that spike S1 time and dose-dependently increased the activity of Cx43 hemichannels in HeLa-Cx43 cells, as measured by dye uptake experiments. These responses were potentiated when the angiotensin-converting enzyme 2 (ACE2) was expressed in HeLa-Cx43 cells. Patch clamp experiments revealed that spike S1 increased unitary current events with conductances compatible with Cx43 hemichannels. In addition, Cx43 hemichannel opening evoked by spike S1 triggered the release of ATP and increased the [Ca2+]i dynamics elicited by ATP. CONCLUSIONS: We hypothesize that Cx43 hemichannels could represent potential pharmacological targets for developing therapies to counteract SARS-CoV-2 infection and their long-term consequences.

Hypertensive Nephropathy: Unveiling the Possible Involvement of Hemichannels and Pannexons.

Hypertension is one of the most common risk factors for developing chronic cardiovascular diseases, including hypertensive nephropathy. Within the glomerulus, hypertension causes damage and activation of mesangial cells (MCs), eliciting the production of large amounts of vasoactive and proinflammatory agents. Accordingly, the activation of AT1 receptors by the vasoactive molecule angiotensin II (AngII) contributes to the pathogenesis of renal damage, which is mediated mostly by the dysfunction of intracellular Ca2+ ([Ca2+]i) signaling. Similarly, inflammation entails complex processes, where [Ca2+]i also play crucial roles. Deregulation of this second messenger increases cell damage and promotes fibrosis, reduces renal blood flow, and impairs the glomerular filtration barrier. In vertebrates, [Ca2+]i signaling depends, in part, on the activity of two families of large-pore channels: hemichannels and pannexons. Interestingly, the opening of these channels depends on [Ca2+]i signaling. In this review, we propose that the opening of channels formed by connexins and/or pannexins mediated by AngII induces the ATP release to the extracellular media, with the subsequent activation of purinergic receptors. This process could elicit Ca2+ overload and constitute a feed-forward mechanism, leading to kidney damage.

GABAergic Regulation of Astroglial Gliotransmission through Cx43 Hemichannels.

Gamma-Aminobutyric acid (GABA) is the primary inhibitory neurotransmitter in the brain. It is produced by interneurons and recycled by astrocytes. In neurons, GABA activates the influx of Cl- via the GABAA receptor or efflux or K+ via the GABAB receptor, inducing hyperpolarization and synaptic inhibition. In astrocytes, the activation of both GABAA and GABAB receptors induces an increase in intracellular Ca2+ and the release of glutamate and ATP. Connexin 43 (Cx43) hemichannels are among the main Ca2+-dependent cellular mechanisms for the astroglial release of glutamate and ATP. However, no study has evaluated the effect of GABA on astroglial Cx43 hemichannel activity and Cx43 hemichannel-mediated gliotransmission. Here we assessed the effects of GABA on Cx43 hemichannel activity in DI NCT1 rat astrocytes and hippocampal brain slices. We found that GABA induces a Ca2+-dependent increase in Cx43 hemichannel activity in astrocytes mediated by the GABAA receptor, as it was blunted by the GABAA receptor antagonist bicuculline but unaffected by GABAB receptor antagonist CGP55845. Moreover, GABA induced the Cx43 hemichannel-dependent release of glutamate and ATP, which was also prevented by bicuculline, but unaffected by CGP. Gliotransmission in response to GABA was also unaffected by pannexin 1 channel blockade. These results are discussed in terms of the possible role of astroglial Cx43 hemichannel-mediated glutamate and ATP release in regulating the excitatory/inhibitory balance in the brain and their possible contribution to psychiatric disorders.

TNF-α Plus IL-1ß Induces Opposite Regulation of Cx43 Hemichannels and Gap Junctions in Mesangial Cells through a RhoA/ROCK-Dependent Pathway.

Connexin 43 (Cx43) is expressed in kidney tissue where it forms hemichannels and gap junction channels. However, the possible functional relationship between these membrane channels and their role in damaged renal cells remains unknown. Here, analysis of ethidium uptake and thiobarbituric acid reactive species revealed that treatment with TNF-α plus IL-1ß increases Cx43 hemichannel activity and oxidative stress in MES-13 cells (a cell line derived from mesangial cells), and in primary mesangial cells. The latter was also accompanied by a reduction in gap junctional communication, whereas Western blotting assays showed a progressive increase in phosphorylated MYPT (a target of RhoA/ROCK) and Cx43 upon TNF-α/IL-1ß treatment. Additionally, inhibition of RhoA/ROCK strongly antagonized the TNF-α/IL-1ß-induced activation of Cx43 hemichannels and reduction in gap junctional coupling. We propose that activation of Cx43 hemichannels and inhibition of cell-cell coupling during pro-inflammatory conditions could contribute to oxidative stress and damage of mesangial cells via the RhoA/ROCK pathway.

Neurodegeneration in Multiple Sclerosis: The Role of Nrf2-Dependent Pathways.

Multiple sclerosis (MS) encompasses a chronic, irreversible, and predominantly immune-mediated disease of the central nervous system that leads to axonal degeneration, neuronal death, and several neurological symptoms. Although various immune therapies have reduced relapse rates and the severity of symptoms in relapsing-remitting MS, there is still no cure for this devastating disease. In this brief review, we discuss the role of mitochondria dysfunction in the progression of MS, focused on the possible role of Nrf2 signaling in orchestrating the impairment of critical cellular and molecular aspects such as reactive oxygen species (ROS) management, under neuroinflammation and neurodegeneration in MS. In this scenario, we propose a new potential downstream signaling of Nrf2 pathway, namely the opening of hemichannels and pannexons. These large-pore channels are known to modulate glial/neuronal function and ROS production as they are permeable to extracellular Ca2+ and release potentially harmful transmitters to the synaptic cleft. In this way, the Nrf2 dysfunction impairs not only the bioenergetics and metabolic properties of glial cells but also the proper antioxidant defense and energy supply that they provide to neurons.

Hematological abnormalities in immunosuppressed patients with COVID-19: Evidence from a single center. A cross sectional study.

BACKGROUND: Changes in hematological parameters in patients with COVID-19 are emerging as important features of the disease in the general population. In the present study we aimed to explore the hematological characteristics and its prevalence proportion ratio in patients with immunosuppression with COVID-19. AIM: To explore the differences between immunosuppressed and non-immunosuppressed patients, with and without COVID-19 from a hematological perspective. METHODS: This cross-sectional study reports on the baseline complete blood count in patients attending the HHA Hospital, in Chile. The study reports descriptive characteristics of the population, including sex, age, ethnicity, corticoids and biological therapy scheme and a complete report of blood test results. A total of 476 patients were enrolled in this study from October of 2020 to April 2021. RESULTS: Findings revels a significant increment (p value ≤ 0.001) on the median of total neutrophils and leucocytes, and in platelet-lymphocyte ratio (PLR), neutrophil- lymphocyte ratio (NLR) and monocyte-lymphocyte ratio (MLR) in immunosuppressed patients with COVID-19 (IS(+)) and immunocompetent patients with COVID-19 (IC(+)) compared with their respective controls. By contrast, a significant reduction on the median of lymphocytes, and eosinophiles was observed in IS(+) individuals compared with its controls. Also, the red blood cell count, hemoglobin, hematocrit, and mean corpuscular hemoglobin concentration were significantly reduced in IS(+) patients, whereas red blood cell, distribution width and mean corpuscular volume, were significantly higher in patients with COVID-19. CONCLUSION: Rapid blood tests, including, neutrophil, lymphocytes count and PLR, NLR can be used for early assessment and management of patients with immunosuppression.

Astroglial gliotransmitters released via Cx43 hemichannels regulate NMDAR-dependent transmission and short-term fear memory in the basolateral amygdala.

Astrocytes release gliotransmitters via connexin 43 (Cx43) hemichannels into neighboring synapses, which can modulate synaptic activity and are necessary for fear memory consolidation. However, the gliotransmitters released, and their mechanisms of action remain elusive. Here, we report that fear conditioning training elevated Cx43 hemichannel activity in astrocytes from the basolateral amygdala (BLA). The selective blockade of Cx43 hemichannels by microinfusion of TAT-Cx43L2 peptide into the BLA induced memory deficits 1 and 24 h after training, without affecting learning. The memory impairments were prevented by the co-injection of glutamate and D-serine, but not by the injection of either alone, suggesting a role for NMDA receptors (NMDAR). The incubation with TAT-Cx43L2 decreased NMDAR-mediated currents in BLA slices, effect that was also prevented by the addition of glutamate and D-serine. NMDARs in primary neuronal cultures were unaffected by TAT-Cx43L2, ruling out direct effects of the peptide on NMDARs. Finally, we show that D-serine permeates through purified Cx43 hemichannels reconstituted in liposomes. We propose that the release of glutamate and D-serine from astrocytes through Cx43 hemichannels is necessary for the activation of post-synaptic NMDARs during training, to allow for the formation of short-term and subsequent long-term memory, but not for learning per se.

Astroglial Hemichannels and Pannexons: The Hidden Link between Maternal Inflammation and Neurological Disorders.

Maternal inflammation during pregnancy causes later-in-life alterations of the offspring's brain structure and function. These abnormalities increase the risk of developing several psychiatric and neurological disorders, including schizophrenia, intellectual disability, bipolar disorder, autism spectrum disorder, microcephaly, and cerebral palsy. Here, we discuss how astrocytes might contribute to postnatal brain dysfunction following maternal inflammation, focusing on the signaling mediated by two families of plasma membrane channels: hemi-channels and pannexons. [Ca2+]i imbalance linked to the opening of astrocytic hemichannels and pannexons could disturb essential functions that sustain astrocytic survival and astrocyte-to-neuron support, including energy and redox homeostasis, uptake of K+ and glutamate, and the delivery of neurotrophic factors and energy-rich metabolites. Both phenomena could make neurons more susceptible to the harmful effect of prenatal inflammation and the experience of a second immune challenge during adulthood. On the other hand, maternal inflammation could cause excitotoxicity by producing the release of high amounts of gliotransmitters via astrocytic hemichannels/pannexons, eliciting further neuronal damage. Understanding how hemichannels and pannexons participate in maternal inflammation-induced brain abnormalities could be critical for developing pharmacological therapies against neurological disorders observed in the offspring.

Síndrome de pseudo-Duane secundario a Schwannoma de nervio abducens: Reporte de caso y revisión / Pseudo-Duane syndrome secondary to abducens nerve schwannoma: Case report and review

Reporte de caso de síndrome de pseudo-Duane asociado a schwannoma de nervio abducens y neurofibromatosis tipo 2 (NF2). Este síndrome es raro, caracterizado por limitación en abducción, retracción ocular, disminución de hendidura palpebral en abducción y restricción del recto medial ipsilateral en test de ducción forzada. La NF2 es también una enfermedad infrecuente caracterizada por tumores de sistema nervioso central y periférico. Los schwannomas de nervio abducens son también poco frecuentes, y se presentan comúnmente con diplopia. Se revisan brevemente estas enfermedades. Es el primer caso reportado de pseudo-Duane secundario a schwannoma de nervio abducens y NF2 según nuestro conocimiento.

A pseudo-Duane syndrome case associated with abducens nerve schwannoma and neurofibromatosis type 2 (NF2) is presented. This syndrome is a rare disease characterised by abduction limitation, ocular retraction, narrowing of the palpebral fissure in abduction, and ipsilateral medial rectus restriction on forced duction test. NF2 is also an uncommon disease which is characterised by peripheral and central nervous system tumours. Abducens nerve schwannomas are also uncommon and presents usually as diplopia. A short review of these diseases is given. This is the first case of pseudo-Duane secondary to abducens nerve schwannoma, to our knowledge.

El consumo de un extracto de calafate (Berberis microphylla) modifica marcadores de respuesta inmune en ratones delgados y obesos

RESUMEN La obesidad ha sido identificada como factor de riesgo de severidad de infecciones respiratorias. Apoyar la respuesta inmune en sujetos obesos es de interés. El presente trabajo evaluó el efecto del consumo de un extracto de calafate sobre marcadores de respuesta inmune en ratones delgados y obesos. Ratones C57BL/6J machos fueron expuestos por 82 días a dieta estándar (DE) y alta en grasas (DAG). A un subgrupo de ambos grupos, se les administró 50 y 100 mg [polifenoles totales]/kg peso de animal/día, de extracto, en las últimas dos semanas. Se evaluó expresión génica y secreción de marcadores de respuesta inmune, en tejido pulmonar y plasma. Se observó un efecto del tratamiento con extracto en la expresión de IFN-ϓ. Se observaron efectos inducidos por la DAG y el tratamiento con extracto de manera independiente, en la expresión de IL-12. Se observó un efecto global de la DAG sobre IFN-ϓ plasmático, específicamente una disminución en animales alimentados con DAG. Se observó una interacción entre la dieta y el tratamiento con extracto sobre IL-12 plasmática. El tratamiento utilizado modula marcadores que activan la respuesta inmune ante infecciones respiratorias principalmente de origen viral, en animales delgados y obesos.

ABSTRACT Obesity has been identified as a risk factor for severity of respiratory infections. Thus, the support of the immune response in obese subjects is of interest. The present work evaluated the effect of the consumption of a calafate extract on markers of the immune response in lean and obese mice. Male C57BL/6J mice were exposed for 82 days to a standard or a high-fat diet (HFD). A subgroup of both groups was given 50 and 100 mg [total polyphenols]/kg body weight/day of extract in the last two weeks. Gene expression and secretion of immune response markers were evaluated in lung tissue and plasma. An effect of extract treatment on IFN-ϓ expression was observed. Effects induced by the HFD and treatment with extract were observed independent of the expression of IL-12. An overall effect of the HF diet on plasma IFN-ϓ was observed, specifically a decrease in animals fed the HFD. An interaction between diet and extract treatment was observed over plasma IL-12. The treatment used modulates markers that activate the immune response to respiratory infections, mainly of viral origin, in lean and obese animals.

Permeation of Molecules through Astroglial Connexin 43 Hemichannels Is Modulated by Cytokines with Parameters Depending on the Permeant Species.

Recent studies indicate that connexin hemichannels do not act as freely permeable non-selective pores, but they select permeants in an isoform-specific manner with cooperative, competitive and saturable kinetics. The aim of this study was to investigate whether the treatment with a mixture of IL-1ß plus TNF-α, a well-known pro-inflammatory condition that activates astroglial connexin 43 (Cx43) hemichannels, could alter their permeability to molecules. We found that IL-1ß plus TNF-α left-shifted the dye uptake rate vs. dye concentration relationship for Etd and 2-NBDG, but the opposite took place for DAPI or YO-PRO-1, whereas no alterations were observed for Prd. The latter modifications were accompanied of changes in Kd (Etd, DAPI, YO-PRO-1 or 2-NBDG) and Hill coefficients (Etd and YO-PRO-1), but not in alterations of Vmax. We speculate that IL-1ß plus TNF-α may distinctively affect the binding sites to permeants in astroglial Cx43 hemichannels rather than their number in the cell surface. Alternatively, IL-1ß plus TNF-α could induce the production of endogenous permeants that may favor or compete for in the pore-lining residues of Cx43 hemichannels. Future studies shall elucidate whether the differential ionic/molecule permeation of Cx43 hemichannels in astrocytes could impact their communication with neurons in the normal and inflamed nervous system.