The Promising Epigenetic Regulators for Refractory Epilepsy: An Adventurous Road Ahead.

The attribution of seizure freedom is yet to be achieved for patients suffering from refractory epilepsy, e.g. Dravet Syndrome (DS). The confined ability of mono-chemical entity-based antiseizure drugs (ASDs) to act directly at genomic level is one of the factors, combined with undetermined seizure triggers lead to recurrent seizure (RS) in DS, abominably affecting the sub-genomic architecture of neural cells. Thus, the RS and ASD appear to be responsible for the spectrum of exorbitant clinical pathology. The RS distresses the 5-HT-serotonin pathway, hypomethylates genes of CNS, and modulates the microRNA (miRNA)/long non-coding RNA (lncRNA), eventually leading to frozen molecular alterations. These changes shall be reverted by compatible epigenetic regulators (EGR) like, miRNA and lncRNA from Breast milk (BML) and Bacopa monnieri (BMI). The absence of studious seizure in SCN1A mutation-positive babies for the first 6 months raises the possibility that the consequences of mutation in SCN1A are subsidized by EGRs from BML. EGR-dependent-modifier gene effect is likely imposed by the other members of the SCN family. Therefore, we advocate that miRNA/lncRNA from BML and bacosides/miRNA from BMI buffer the effect of SCN1A mutation by sustainably maintaining modifier gene effect in the aberrant neurons. The presence of miRNA-155-5p, -30b-5p, and -30c-5p family in BML and miR857, miR168, miR156, and miR158 in BMI target at regulating SCN family and CLCN5 as visualized by Cystoscope. Thus, we envisage that the possible effects of EGR might include (a) upregulating the haploinsufficient SCN1A strand, (b) down-regulating seizure-elevated miRNA, (c) suppressing the seizure-induced methyltransferases, and (d) enhancing the GluN2A subunit of NMDA receptor to improve cognition. The potential of these EGRs from BML and BML is to further experimentally strengthen, long-haul step forward in molecular therapeutics.

Cardiac Mitochondrial PTEN-L determines cell fate between apoptosis and survival during chronic alcohol consumption.

Chronic alcohol consumption induces myocardial damage and a type of non-ischemic cardiomyopathy termed alcoholic cardiomyopathy, where mitochondrial ultrastructural damages and suppressed fusion activity promote cardiomyocyte apoptosis. The aim of the present study is to determine the role of mitochondrial fission proteins and/or other proteins that localise on cardiac mitochondria for apoptosis upon ethanol consumption. In vivo and in vitro chronic alcohol exposure increased mitochondrial Drp1 levels but knockdown of the same did not confer cardioprotection in H9c2 cells. These cells displayed downregulated expression of MFN2 and OPA1 for Bak-mediated cytochrome c release and apoptosis. Dysregulated PTEN/AKT cell survival signal in both ethanol treated and Drp1 knockdown cells augmented oxidative stress by promoting  mitochondrial PTEN-L and MFN1 interaction. Inhibiting this interaction with VO-OHpic, a reversible PTEN inhibitor, prevented Bak insertion into the mitochondria and release of cytochrome c to cytoplasm. Thus, our study provides evidence that Drp1-mediated mitochondrial fission is dispensable for ethanol-induced cardiotoxicity and that stress signals induce mitochondrial PTEN-L accumulation for structural and functional dyshomeostasis. Our in vivo results also demonstrates the therapeutic potential of VO-OHpic for habitual alcoholics developing myocardial dysfunction.

Mitochondrial Ca2+ Uniporter Is a Mitochondrial Luminal Redox Sensor that Augments MCU Channel Activity.

Ca2+ dynamics and oxidative signaling are fundamental mechanisms for mitochondrial bioenergetics and cell function. The MCU complex is the major pathway by which these signals are integrated in mitochondria. Whether and how these coactive elements interact with MCU have not been established. As an approach toward understanding the regulation of MCU channel by oxidative milieu, we adapted inflammatory and hypoxia models. We identified the conserved cysteine 97 (Cys-97) to be the only reactive thiol in human MCU that undergoes S-glutathionylation. Furthermore, biochemical, structural, and superresolution imaging analysis revealed that MCU oxidation promotes MCU higher order oligomer formation. Both oxidation and mutation of MCU Cys-97 exhibited persistent MCU channel activity with higher [Ca2+]m uptake rate, elevated mROS, and enhanced [Ca2+]m overload-induced cell death. In contrast, these effects were largely independent of MCU interaction with its regulators. These findings reveal a distinct functional role for Cys-97 in ROS sensing and regulation of MCU activity.

S-glutathionylation activates STIM1 and alters mitochondrial homeostasis.

Oxidant stress influences many cellular processes, including cell growth, differentiation, and cell death. A well-recognized link between these processes and oxidant stress is via alterations in Ca(2+) signaling. However, precisely how oxidants influence Ca(2+) signaling remains unclear. Oxidant stress led to a phenotypic shift in Ca(2+) mobilization from an oscillatory to a sustained elevated pattern via calcium release-activated calcium (CRAC)-mediated capacitive Ca(2+) entry, and stromal interaction molecule 1 (STIM1)- and Orai1-deficient cells are resistant to oxidant stress. Functionally, oxidant-induced Ca(2+) entry alters mitochondrial Ca(2+) handling and bioenergetics and triggers cell death. STIM1 is S-glutathionylated at cysteine 56 in response to oxidant stress and evokes constitutive Ca(2+) entry independent of intracellular Ca(2+) stores. These experiments reveal that cysteine 56 is a sensor for oxidant-dependent activation of STIM1 and demonstrate a molecular link between oxidant stress and Ca(2+) signaling via the CRAC channel.