Energy substrate metabolism, mitochondrial structure and oxidative stress after cardiac ischemia-reperfusion in mice lacking UCP3.

Myocardial ischemia-reperfusion (IR) injury may result in cardiomyocyte dysfunction. Mitochondria play a critical role in cardiomyocyte recovery after IR injury. The mitochondrial uncoupling protein 3 (UCP3) has been proposed to reduce mitochondrial reactive oxygen species (ROS) production and to facilitate fatty acid oxidation. As both mechanisms might be protective following IR injury, we investigated functional, mitochondrial structural, and metabolic cardiac remodeling in wild-type mice and in mice lacking UCP3 (UCP3-KO) after IR. Results showed that infarct size in isolated perfused hearts subjected to IR ex vivo was larger in adult and old UCP3-KO mice than in equivalent wild-type mice, and was accompanied by higher levels of creatine kinase in the effluent and by more pronounced mitochondrial structural changes. The greater myocardial damage in UCP3-KO hearts was confirmed in vivo after coronary artery occlusion followed by reperfusion. S1QEL, a suppressor of superoxide generation from site IQ in complex I, limited infarct size in UCP3-KO hearts, pointing to exacerbated superoxide production as a possible cause of the damage. Metabolomics analysis of isolated perfused hearts confirmed the reported accumulation of succinate, xanthine and hypoxanthine during ischemia, and a shift to anaerobic glucose utilization, which all recovered upon reoxygenation. The metabolic response to ischemia and IR was similar in UCP3-KO and wild-type hearts, being lipid and energy metabolism the most affected pathways. Fatty acid oxidation and complex I (but not complex II) activity were equally impaired after IR. Overall, our results indicate that UCP3 deficiency promotes enhanced superoxide generation and mitochondrial structural changes that increase the vulnerability of the myocardium to IR injury.

Development and Characterization of Films with Propolis to Inhibit Mold Contamination in the Dairy Industry.

Due to the number of polyphenols with multiple biological activities, propolis has high potential to be used as an active agent in food protective films. Therefore, this study aimed to develop and characterize a sodium alginate film with ethanolic extract of propolis (EEP) for its potential use as protective active packaging against filamentous fungi in ripened cheese. Three different concentrations of EEP were analyzed: 0, 5 and 10% w/v. The films obtained were characterized, assessing thermal and physicochemical properties, as well as the concentration of polyphenols in the EEP and antifungal activity of the active films. The incorporation of EEP in the films generated thermal stability with respect to the loss of mass. Total color values (ΔE) of the films were affected by the incorporation of the different concentrations of EEP, showing a decrease in luminosity (L*) of the films, while the chromatic parameters a* and b* increased in direct proportion to the EEP concentration. Antifungal activity was observed with a fungistatic mode of action, stopping the growth of the fungus in cheeses without development of filamentous molds, thus increasing the shelf life of the ripened cheese under the analytical conditions, over 30 days at room temperature. Overall, EEP can be used to prevent growth and proliferation of spoilage microorganisms in cheese.

48-Week effectiveness and tolerability of dolutegravir (DTG) + lamivudine (3TC) in antiretroviral-naïve adults living with HIV: A multicenter real-life cohort.

BACKGROUND: The main international guidelines indicate DTG/3TC therapy as one of the preferred regimens for people living with HIV (PLWH), due to its observed efficacy in randomized clinical trials. However, information in real-life cohorts is relatively scarce for first-line use. METHODS: A retrospective multicenter study of adult PLWH starting DTG+3TC as a first-line regimen before January 31st, 2020. Virological failure (VF) was defined as 2 consecutive HIV RNA viral load (VL) >50 copies/mL. RESULTS: 135 participants were included. Treatment was started without knowing baseline drug resistance testing (bDRT) results in 71.9% of cases, with baseline resistance mutations being later confirmed in 17 patients (12.6%), two of them with presence of M184V mutation. Effectiveness at week 48 was 85.2% (CI95%: 78.1-90.7%) (ITT missing = failure [M = F]) and 96.6% (CI 95%: 91.6-99.1%) (per-protocol analysis). Six patients (4.4%) discontinued treatment. One developed not confirmed VF after discontinuing treatment due to poor adherence; no resistance-associated mutations emerged. Three discontinued treatments due to central nervous system side effects (2.2%), and two due to a medical decision after determining the M184V mutation in bDRT. Finally, 14 (10.4%) were lost to follow-up, most of them due to the COVID-19 pandemic. CONCLUSIONS: In a real-life multicenter cohort of ART-naïve PLWH, treatment initiation with DTG + 3TC showed high effectiveness and favorable safety results, comparable to those of randomized clinical trials, without treatment-emergent resistance being observed through week 48. Starting treatment before receiving the results of baseline drug resistance testing did not have an impact on the regimen's effectiveness.

Clinical Thresholds for Pseudohyperkalemia and Pseudonormokalemia in Patients with Thrombocytosis.

Background: The lysis of platelets during in vitro coagulation leads to increased potassium concentrations.We aimed to establish the cut-off value for platelet count interfering serum potassium and to estimate the percentage of cases of pseudohyperkalemia and pseudonormokalemia in our hospital. Materials and methods: Individuals diagnosed with essential thrombocytosis (2010-2019) based on the WHO criteria for the classification of myeloid neoplasms and acute leukemia were considered.The cut-off value for the interference of platelet count on serum potassium results was calculated using the reference change value. Sensitivity and specificity were calculated using a ROC-curve, and the size of the effect by the Cohen's d.The clinical impact of both phenomena was assessed by reviewing the medical records of individuals classified as such, and also looking for potential cases in 2019 on the laboratory information system. Results: Fifty-four individuals with essential thrombocytosis were included. Potassium concentration correlated with platelet count (P-value<0.001; Spearman's ρ =0.394) in serum. The cut-off value of platelet count interfering potassium was 598x103/µL [CI95%: 533-662x103/µL], with an associated sensitivity and specificity of 0.67 [CI95%:0.52-0.80] and 0.58 [CI95%:0.42-0.72] respectively.The medical records of patients classified as pseudohyperkalemia or pseudonormokalemia did not include any medical action for the modification of potassium levels. In 2019, up to 0.14% of the total serum potassium determinations were susceptible to be pseudohyperkalemia or pseudonormokalemia. Conclusion: This study provides a cut-off value for platelet count interfering serum potassium concentrations, and brings to light not only pseudohyperkalemia-related issues, but also the pseudonormokalemia phenomenon, which usually goes unnoticed.

Identification of Two Novel EPOR Gene Variants in Primary Familial Polycythemia: Case Report and Literature Review.

Primary familial and congenital polycythemia is a rare disease characterized by an increase in red cell mass that may be due to pathogenic variants in the EPO receptor (EPOR) gene. To date, 33 genetic variants have been reported to be associated. We analyzed the presence of EPOR variants in two patients with polycythemia in whom JAK2 pathogenic variants had been previously discarded. Molecular analysis of the EPOR gene was performed by Sanger sequencing of the coding regions and exon/intron boundaries of exon 8. We performed in vitro culture of erythroid progenitor cells. Segregation studies were done whenever possible. The two patients studied showed hypersensitivity to EPO in in vitro cultures. Analysis of the EPOR gene unveiled two novel pathogenic variants. Genetic testing of asymptomatic relatives could guarantee surveillance and proper management.

Biodegradable gelatin-based films with nisin and EDTA that inhibit Escherichia coli.

In this study, we developed gelatin-based films for active packaging with the ability to inhibit E. coli. We created these novel biodegradable gelatin-based films with a nisin-EDTA mix. FT-IR, TGA, and SEM analysis showed that nisin interacted with the gelatin by modifying its thermal stability and morphology. The use of nisin (2,500 IU/mL) with concentrations of Na-EDTA (1.052 M stock solution) distributed in the polymer matrix generated a significant decrease in the growth of E. coli when compared to the control. In freshly made films (t0), the growth of E. coli ATCC 25922 was reduced by approximately 3 logarithmic cycles. Two weeks after the films were made, a reduction in antimicrobial activity was observed in approximately 1, 1 and 3 logarithmic cycles of the films with 5%, 10% and 20% of the compound (nisin/Na-EDTA) distributed in the polymer matrix, respectively. This evidences an antimicrobial effect over time. Also, biodegradation tests showed that the films were completely degraded after 10 days. With all these results, an active and biodegradable packaging was successfully obtained to be potentially applied in perishable foods. These biodegradable, gelatin-based films are a versatile active packaging option. Further research on the barrier properties of these films is needed.

Hydrolyzable Poly(ß-thioether ester ketal) Thermosets via Acyclic Ketal Monomers.

Hydrolytically degradable poly(ß-thioether ester ketal) thermosets are synthesized via radical-mediated thiol-ene photopolymerization using three novel dialkene acyclic ketal monomers and a mercaptopropionate based tetrafunctional thiol. For all thermoset compositions investigated, degradation behavior is highly tunable based on the structure of the incorporated ketal and pH. Complete degradation of the thermosets is observed upon exposure to acidic and neutral pH, and under high humidity conditions. Polymer networks composed of cross-link junctions based on acyclic dimethyl ketals degrade the quickest, whereas networks containing acyclic cyclohexyl ketals undergo hydrolytic degradation on a longer timescale. Thermomechanical analysis reveals low glass transition temperatures and moduli typical of thioether-based thermosets.

Targeting autotaxin impacts disease advance in the SOD1-G93A mouse model of amyotrophic lateral sclerosis.

A preclinical strategy to broaden the search of potentially effective treatments in amyotrophic lateral sclerosis (ALS) relies on identifying factors controlling motor neuron (MN) excitability. These partners might be part of still unknown pathogenic pathways and/or useful for the design of new interventions to affect disease progression. In this framework, the bioactive membrane-derived phospholipid lysophosphatidic acid (LPA) affects MN excitability through LPA receptor 1 (LPA1 ). Furthermore, LPA1  knockdown is neuroprotective in transgenic ALS SOD1-G93A mice. On this basis, we raised the hypothesis that the major LPA-synthesizing ectoenzyme, autotaxin (ATX), regulates MN excitability and is a potential target to modulate disease development in ALS mice. We show here that PF-8380, a specific ATX inhibitor, reduced intrinsic membrane excitability (IME) of hypoglossal MNs in brainstem slices, supporting that baseline ATX activity regulates MN IME. PF-8380-induced alterations were prevented by a small-interfering RNA directed against mRNA for lpa1 . These outcomes support that impact of ATX-originated lysophospholipids on MN IME engages, at least, the G-protein-coupled receptor LPA1 . Interestingly, mRNAatx levels increased in the spinal cord of pre-symptomatic (1-2 months old) SOD1-G93A mice, thus preceding MN loss. The rise in transcripts levels also occurred in cultured spinal cord MNs from SOD1-G93A embryos, suggesting that mRNAatx upregulation in MNs is an etiopathogenic event in the ALS cell model. Remarkably, chronic administration in the drinking water of the orally bioavailable ATX inhibitor PF-8380 delayed MN loss, motor deterioration and prolonged life span in ALS mice. Treatment also led to a reduction in LPA1 -immunoreactive patches in transgenic animals mostly in MNs. These outcomes support that neuroprotective effects of interfering with ATX in SOD1-G93A mice rely, at least in part, on LPA1  knockdown in MNs. Therefore, we propose ATX as a potential target and/or a biomarker in ALS and highlight ATX inhibitors as reasonable tools with therapeutic usefulness for this lethal pathology.

Lysophosphatidic Acid and Several Neurotransmitters Converge on Rho-Kinase 2 Signaling to Manage Motoneuron Excitability.

Intrinsic membrane excitability (IME) sets up neuronal responsiveness to synaptic drive. Several neurotransmitters and neuromodulators, acting through G-protein-coupled receptors (GPCRs), fine-tune motoneuron (MN) IME by modulating background K+ channels TASK1. However, intracellular partners linking GPCRs to TASK1 modulation are not yet well-known. We hypothesized that isoform 2 of rho-kinase (ROCK2), acting as downstream GPCRs, mediates adjustment of MN IME via TASK1. Electrophysiological recordings were performed in hypoglossal MNs (HMNs) obtained from adult and neonatal rats, neonatal knockout mice for TASK1 (task1 -/-) and TASK3 (task3 -/-, the another highly expressed TASK subunit in MNs), and primary cultures of embryonic spinal cord MNs (SMNs). Small-interfering RNA (siRNA) technology was also used to knockdown either ROCK1 or ROCK2. Furthermore, ROCK activity assays were performed to evaluate the ability of various physiological GPCR ligands to stimulate ROCK. Microiontophoretically applied H1152, a ROCK inhibitor, and siRNA-induced ROCK2 knockdown both depressed AMPAergic, inspiratory-related discharge activity of adult HMNs in vivo, which mainly express the ROCK2 isoform. In brainstem slices, intracellular constitutively active ROCK2 (aROCK2) led to H1152-sensitive HMN hyper-excitability. The aROCK2 inhibited pH-sensitive and TASK1-mediated currents in SMNs. Conclusively, aROCK2 increased IME in task3 -/-, but not in task1 -/- HMNs. MN IME was also augmented by the physiological neuromodulator lysophosphatidic acid (LPA) through a mechanism entailing Gαi/o-protein stimulation, ROCK2, but not ROCK1, activity and TASK1 inhibition. Finally, two neurotransmitters, TRH, and 5-HT, which are both known to increase MN IME by TASK1 inhibition, stimulated ROCK2, and depressed background resting currents via Gαq/ROCK2 signaling. These outcomes suggest that LPA and several neurotransmitters impact MN IME via Gαi/o/Gαq-protein-coupled receptors, downstream ROCK2 activation, and subsequent inhibition of TASK1 channels.

Interfering with lysophosphatidic acid receptor edg2/lpa1 signalling slows down disease progression in SOD1-G93A transgenic mice.

AIMS: Alterations in excitability represent an early hallmark in Amyotrophic Lateral Sclerosis (ALS). Therefore, deciphering the factors that impact motor neuron (MN) excitability offers an opportunity to uncover further aetiopathogenic mechanisms, neuroprotective agents, therapeutic targets, and/or biomarkers in ALS. Here, we hypothesised that the lipokine lysophosphatidic acid (lpa) regulates MN excitability via the G-protein-coupled receptor lpa1 . Then, modulating lpa1 -mediated signalling might affect disease progression in the ALS SOD1-G93A mouse model. METHODS: The influence of lpa-lpa1 signalling on the electrical properties, Ca2+ dynamic and survival of MNs was tested in vitro. Expression of lpa1 in cultured MNs and in the spinal cord of SOD1-G93A mice was analysed. ALS mice were chronically treated with a small-interfering RNA against lpa1 (siRNAlpa1 ) or with the lpa1 inhibitor AM095. Motor skills, MN loss, and lifespan were evaluated. RESULTS: AM095 reduced MN excitability. Conversely, exogenous lpa increased MN excitability by modulating task1 'leak' potassium channels downstream of lpa1 . Lpa-lpa1 signalling evoked an excitotoxic response in MNs via voltage-sensitive calcium channels. Cultured SOD1-G93A MNs displayed lpa1 upregulation and heightened vulnerability to lpa. In transgenic mice, lpa1 was upregulated mostly in spinal cord MNs before cell loss. Chronic administration of either siRNAlpa1 or AM095 reduced lpa1 expression at least in MNs, delayed MN death, improved motor skills, and prolonged life expectancy of ALS mice. CONCLUSIONS: These results suggest that stressed lpa-lpa1 signalling contributes to MN degeneration in SOD1-G93A mice. Consequently, disrupting lpa1 slows down disease progression. This highlights LPA1 signalling as a potential target and/or biomarker in ALS.

Nitric oxide controls excitatory/inhibitory balance in the hypoglossal nucleus during early postnatal development.

Synaptic remodeling during early postnatal development lies behind neuronal networks refinement and nervous system maturation. In particular, the respiratory system is immature at birth and is subjected to significant postnatal development. In this context, the excitatory/inhibitory balance dramatically changes in the respiratory-related hypoglossal nucleus (HN) during the 3 perinatal weeks. Since, development abnormalities of hypoglossal motor neurons (HMNs) are associated with sudden infant death syndrome and obstructive sleep apnea, deciphering molecular partners behind synaptic remodeling in the HN is of basic and clinical relevance. Interestingly, a transient expression of the neuronal isoform of nitric oxide (NO) synthase (NOS) occurs in HMNs at neonatal stage that disappears before postnatal day 21 (P21). NO, in turn, is a determining factor for synaptic refinement in several physiopathological conditions. Here, intracerebroventricular chronic administration (P7-P21) of the broad spectrum NOS inhibitor L-NAME (N(ω)-nitro-L-arginine methyl ester) differentially affected excitatory and inhibitory rearrangement during this neonatal interval in the rat. Whilst L-NAME led to a reduction in the number of excitatory structures, inhibitory synaptic puncta were increased at P21 in comparison to administration of the inactive stereoisomer D-NAME. Finally, L-NAME decreased levels of the phosphorylated form of myosin light chain in the nucleus, which is known to regulate the actomyosin contraction apparatus. These outcomes indicate that physiologically synthesized NO modulates excitatory/inhibitory balance during early postnatal development by acting as an anti-synaptotrophic and/or synaptotoxic factor for inhibitory synapses, and as a synaptotrophin for excitatory ones. The mechanism of action could rely on the modulation of the actomyosin contraction apparatus.

Sp1-regulated expression of p11 contributes to motor neuron degeneration by membrane insertion of TASK1.

Disruption in membrane excitability contributes to malfunction and differential vulnerability of specific neuronal subpopulations in a number of neurological diseases. The adaptor protein p11, and background potassium channel TASK1, have overlapping distributions in the CNS. Here, we report that the transcription factor Sp1 controls p11 expression, which impacts on excitability by hampering functional expression of TASK1. In the SOD1-G93A mouse model of ALS, Sp1-p11-TASK1 dysregulation contributes to increased excitability and vulnerability of motor neurons. Interference with either Sp1 or p11 is neuroprotective, delaying neuron loss and prolonging lifespan in this model. Nitrosative stress, a potential factor in human neurodegeneration, stimulated Sp1 expression and human p11 promoter activity, at least in part, through a Sp1-binding site. Disruption of Sp1 or p11 also has neuroprotective effects in a traumatic model of motor neuron degeneration. Together our work suggests the Sp1-p11-TASK1 pathway is a potential target for treatment of degeneration of motor neurons.

Enhancement of anion recognition exhibited by a zinc-imidazole-based ion-pair receptor composed of C-H hydrogen- and halogen-bond donor groups.

A 2-haloimidazole-tetraphenylethylene ion-pair receptor 1 is shown to recognise only HSO4- anions in the presence of a cobound Zn2+ cation guest species, which induced a remarkable increase with concomitant blue shift of the emission band of the complex [1·2Zn]4+ whereas no affinity of the free receptor 1 by the anions is observed. In addition, the downfield shifts observed by 1H NMR of the Ha, Hb and Hc protons of the complex [1·2Zn]4+ upon the addition of HSO4- anions indicate their participation in the recognition event. According to DFT studies, upon chelating a Zn2+ cation with two imidazole nitrogen atoms, receptor 1 adopts a conformation ideally fitted to recognise HSO4- through a combination of C(sp2)-HO and C(sp3)-HO hydrogen bondings, C+(sp2)-BrO halogen bonding and C(sp2)O tetrel bonding.

[Oligoarthritis, panniculitis and pyoderma gangrenosum associated with non-Hodgkin lymphoma. Report of one case]. / Oligoartritis, paniculitis y pioderma gangrenoso como manifestaciones de un Linfoma no Hodgkin.

An assortment of clinical and laboratory abnormalities may occur as paraneoplastic syndromes in lymphomas. Rheumatological and dermatological manifestations such as paraneoplastic arthritis and pyoderma gangrenosum must be underscored. We report a 28 years old woman who developed pyoderma gangrenosum and two years later presented with arthritis of knees and ankles associated with panniculitis interpreted as erythema induratum that was pathologically confirmed. She developed a reactivation of pyoderma gangrenosum, that was refractory to treatment. Complementary studies showed a pulmonary nodule and a right paravertebral mass with involvement of the psoas muscle. Biopsies of both masses and a new pathological skin study demonstrated a large B-cell non-Hodgkin's lymphoma.

Oligoartritis, paniculitis y pioderma gangrenoso como manifestaciones de un Linfoma no Hodgkin / Oligoarthritis, panniculitis and pyoderma gangrenosum associated with non-Hodgkin lymphoma: report of one case

An assortment of clinical and laboratory abnormalities may occur as paraneoplastic syndromes in lymphomas. Rheumatological and dermatological manifestations such as paraneoplastic arthritis and pyoderma gangrenosum must be underscored. We report a 28 years old woman who developed pyoderma gangrenosum and two years later presented with arthritis of knees and ankles associated with panniculitis interpreted as erythema induratum that was pathologically confirmed. She developed a reactivation of pyoderma gangrenosum, that was refractory to treatment. Complementary studies showed a pulmonary nodule and a right paravertebral mass with involvement of the psoas muscle. Biopsies of both masses and a new pathological skin study demonstrated a large B-cell non-Hodgkin's lymphoma.

Heme-Oxygenase I and PCG-1α Regulate Mitochondrial Biogenesis via Microglial Activation of Alpha7 Nicotinic Acetylcholine Receptors Using PNU282987.

AIMS: A loss in brain acetylcholine and cholinergic markers, subchronic inflammation, and impaired mitochondrial function, which lead to low-energy production and high oxidative stress, are common pathological factors in several neurodegenerative diseases (NDDs). Glial cells are important for brain homeostasis, and microglia controls the central immune response, where α7 acetylcholine nicotinic receptors (nAChR) seem to play a pivotal role; however, little is known about the effects of this receptor in metabolism. Therefore, the aim of this study was to evaluate if glial mitochondrial energetics could be regulated through α7 nAChR. RESULTS: Primary glial cultures treated with the α7 nicotinic agonist PNU282987 increased their mitochondrial mass and their mitochondrial oxygen consumption without increasing oxidative stress; these changes were abolished when nuclear erythroid 2-related factor 2 (Nrf2) was absent, heme oxygenase-1 (HO-1) was inhibited, or peroxisome proliferator-activated receptor gamma coactivator 1α (PGC-1α) was silenced. More specifically, microglia of animals treated intraperitoneally with the α7 nAChR agonist PNU282987 (10 mg/kg) showed a significant increase in mitochondrial mass. Interestingly, LysMcre-Hmox1Δ/Δ and PGC-1α-/- animals showed lower microglial mitochondrial levels and treatment with PNU282987 did not produce effects on mitochondrial levels. INNOVATION: Increases in microglial mitochondrial mass and metabolism can be achieved via α7 nAChR by a mechanism that implicates Nrf2, HO-1, and PGC-1α. This signaling pathway could open a new strategy for the treatment of NDDs, such as Alzheimer's, characterized by a reduction of cholinergic markers. CONCLUSION: α7 nAChR signaling increases glial mitochondrial mass, both in vitro and in vivo, via HO-1 and PCG-1α. These effects could be of potential benefit in the context of NDDs. Antioxid. Redox Signal. 27, 93-105.

Fetal Val108/158Met catechol-O-methyltransferase (COMT) polymorphism and placental COMT activity are associated with the development of preeclampsia.

OBJECTIVE: To evaluate the association between fetal and maternal catechol-O-methyltransferase (COMT) Val158Met and methyl tetrahydrofolate reductase (MTHFR) C677T functional polymorphisms and preeclampsia, examining its influence on placental COMT and in maternal 2-methoxyestradiol (2-ME) plasma levels. DESIGN: Prospective case-control study. SETTING: University hospital. PATIENT(S): A total of 53 preeclamptic and 72 normal pregnant women. INTERVENTION(S): Maternal and cord blood samples and placental tissue samples were obtained. MAIN OUTCOME MEASURE(S): Maternal and fetal COMT and MTHFR polymorphisms were genotyped. Maternal plasma 2-ME and homocysteine levels, and expression and activity of placental COMT were measured. RESULT(S): The odds ratio for the risk of preeclampsia for fetal COMT Met/Met was 3.22, and it increased to 8.65 when associated with fetal MTHFR TT. Placental COMT activity and expression were influenced by genotype, but COMT activity in preeclamptic placentas did not differ from control pregnancies. There was no association between any genotypes and maternal 2-ME. Homocysteine levels were higher in women with preeclampsia than in normal pregnancies, and were inversely correlated with 2-ME plasma levels, indicating that its altered metabolism may lower COMT activity in vivo. CONCLUSION(S): Fetal Met-Met COMT genotype reduces COMT placental expression and activity in vitro and increases preeclampsia, risk but it does not explain the difference in maternal 2-ME levels between preeclamptic and normal pregnancies. However, the preeclamptic patients had elevated homocysteine levels that correlated inversely with 2-ME, indicating that an altered methionine-homocysteine metabolism may contribute to reduce COMT activity in vivo and explain the decreased levels of 2-ME in preeclamptic women.

Membrane-derived phospholipids control synaptic neurotransmission and plasticity.

Synaptic communication is a dynamic process that is key to the regulation of neuronal excitability and information processing in the brain. To date, however, the molecular signals controlling synaptic dynamics have been poorly understood. Membrane-derived bioactive phospholipids are potential candidates to control short-term tuning of synaptic signaling, a plastic event essential for information processing at both the cellular and neuronal network levels in the brain. Here, we showed that phospholipids affect excitatory and inhibitory neurotransmission by different degrees, loci, and mechanisms of action. Signaling triggered by lysophosphatidic acid (LPA) evoked rapid and reversible depression of excitatory and inhibitory postsynaptic currents. At excitatory synapses, LPA-induced depression depended on LPA1/Gαi/o-protein/phospholipase C/myosin light chain kinase cascade at the presynaptic site. LPA increased myosin light chain phosphorylation, which is known to trigger actomyosin contraction, and reduced the number of synaptic vesicles docked to active zones in excitatory boutons. At inhibitory synapses, postsynaptic LPA signaling led to dephosphorylation, and internalization of the GABAAγ2 subunit through the LPA1/Gα12/13-protein/RhoA/Rho kinase/calcineurin pathway. However, LPA-induced depression of GABAergic transmission was correlated with an endocytosis-independent reduction of GABAA receptors, possibly by GABAAγ2 dephosphorylation and subsequent increased lateral diffusion. Furthermore, endogenous LPA signaling, mainly via LPA1, mediated activity-dependent inhibitory depression in a model of experimental synaptic plasticity. Finally, LPA signaling, most likely restraining the excitatory drive incoming to motoneurons, regulated performance of motor output commands, a basic brain processing task. We propose that lysophospholipids serve as potential local messengers that tune synaptic strength to precedent activity of the neuron.

4-Hydroxynonenal induces Nrf2-mediated UCP3 upregulation in mouse cardiomyocytes.

4-Hydroxy-2-nonenal (HNE) is a highly cytotoxic product of lipid peroxidation. Nevertheless, at low concentrations, it is able to mediate cell signaling and to activate protective pathways, including that of the transcription factor Nrf2 (nuclear factor erythroid 2-related factor 2). In addition, HNE activates uncoupling proteins (UCPs), mitochondrial inner membrane proteins that mediate uncoupling of oxidative phosphorylation and have been proposed to protect against oxidative stress. It is not known, however, whether HNE might induce UCP expression via Nrf2 to cause mitochondrial uncoupling. We investigated the effects of HNE on UCP3 expression in mouse cardiomyocytes and the involvement of Nrf2. HNE induced the nuclear accumulation of Nrf2 and enhanced UCP3 expression, effects prevented by the antioxidant N-acetylcysteine. ChIP assays indicated that Nrf2 bound to the Ucp3 promoter after HNE treatment, increasing its expression. Cardiomyocytes treated with Nrf2- or UCP3-specific siRNA were less tolerant to HNE as reflected by increased cell death, and Nrf2 siRNA prevented HNE-induced UCP3 upregulation. The treatment with HNE greatly altered cardiomyocyte bioenergetics, increasing the proton leak across the inner mitochondrial membrane and severely decreasing the maximal respiratory capacity and the respiratory reserve capacity. These findings confirm that low HNE doses activate Nrf2 in cardiomyocytes and provide the first evidence of Nrf2 binding to the Ucp3 promoter in response to HNE, leading to increased protein expression. These results suggest that the upregulation of UCP3 mediated by Nrf2 in response to HNE might be important in the protection of the heart under conditions of oxidative stress such as ischemia-reperfusion.