Binge drinking is associated with increased risk for cerebrovascular spasm and stroke. Acute exposure to ethanol at concentrations obtained during binge drinking constricts cerebral arteries in several species, including humans, but the mechanisms underlying this action are largely unknown. In a rodent model, we used fluorescence microscopy, patch-clamp electrophysiology, and pharmacological studies in intact cerebral arteries to pinpoint the molecular effectors of ethanol cerebrovascular constriction. Clinically relevant concentrations of ethanol elevated wall intracellular Ca 2؉ concentration and caused a reversible constriction of cerebral arteries (EC50 ‫؍‬ 27 mM; Emax ‫؍‬ 100 mM) that depended on voltage-gated Ca 2؉ entry into myocytes. However, ethanol did not directly increase voltage-dependent Ca 2؉ currents in isolated myocytes. Constriction occurred because of an ethanol reduction in the frequency (؊53%) and amplitude (؊32%) of transient Ca 2؉ -activated K ؉ (BK) currents. Ethanol inhibition of BK transients was caused by a reduction in Ca 2؉ spark frequency (؊49%), a subsarcolemmal Ca 2؉ signal that evokes the BK transients, and a direct inhibition of BK channel steady-state activity (؊44%). In contrast, ethanol failed to modify Ca 2؉ waves, a major vasoconstrictor mechanism. Selective block of BK channels largely prevented ethanol constriction in pressurized arteries. This study pinpoints the Ca 2؉ spark͞BK channel negative-feedback mechanism as the primary effector of ethanol vasoconstriction.M oderate-heavy episodic alcohol intake, such as in binge drinking, remains a major public health problem (1, 2). Moderate-heavy drinking is associated, independently of any other factor, with an increased risk for stroke and deaths from ischemic stroke (3, 4). Binge drinkers are significantly predisposed to brain hemorrhage, cerebrovascular spasm, and stroke (3, 5).Cerebrovascular disease associated with moderate-heavy alcohol intake is independent of beverage type and alcohol metabolism but linked to ethanol (EtOH) itself (6, 7). Strong evidence for a dose-response relationship between EtOH intake and risk for stroke suggests causality (8). EtOH cerebral artery constriction is considered responsible for cerebral vasospasm, ischemia, and stroke in moderate-heavy drinkers (6, 9). Acute EtOH at legally intoxicating (Ն20 mM) blood levels in naive subjects constricts cerebral arteries in several species, including humans (7, 9).Rats are excellent models to study EtOH cerebral artery constriction and stroke (7,10,11). Evidence from this and other species indicates that EtOH constricts cerebral arteries by acting primarily on the smooth muscle (7,11,12). However, the molecular mechanisms mediating EtOH cerebral artery constriction remain largely unidentified.In cerebrovascular smooth muscle, an elevation in global intracellular Ca 2ϩ ([Ca 2ϩ ] ic ) leads to contraction (13). Ca 2ϩ mobilization in response to EtOH may result from direct potentiation of mechanisms leading to Ca 2ϩ influx͞release from internal organel...

In response to vascular injury, vascular smooth muscle cells (VSMCs) may switch from a contractile to a proliferative phenotype thereby contributing to neointima formation. Previous studies showed that the long noncoding RNA (lncRNA) is critical for paraspeckle formation and tumorigenesis by promoting cell proliferation and migration. However, the role of in VSMC phenotypic modulation is unknown. Herein we showed that expression was induced in VSMCs during phenotypic switching in vivo and in vitro. Silencing in VSMCs resulted in enhanced expression of SM-specific genes while attenuating VSMC proliferation and migration. Conversely, overexpression of in VSMCs had opposite effects. These in vitro findings were further supported by in vivo studies in which knockout mice exhibited significantly decreased neointima formation following vascular injury, due to attenuated VSMC proliferation. Mechanistic studies demonstrated that sequesters the key chromatin modifier WDR5 (WD Repeat Domain 5) from SM-specific gene loci, thereby initiating an epigenetic "off" state, resulting in down-regulation of SM-specific gene expression. Taken together, we demonstrated an unexpected role of the lncRNA in regulating phenotypic switching by repressing SM-contractile gene expression through an epigenetic regulatory mechanism. Our data suggest that is a therapeutic target for treating occlusive vascular diseases.

Pluripotent stem cells have the remarkable self-renewal ability and are capable of differentiating into multiple diverse cells. There is increasing evidence that the aging process can have adverse effects on stem cells. As stem cells age, their renewal ability deteriorates and their ability to differentiate into the various cell types is altered. Accordingly, it is suggested aging-induced deterioration of stem cell functions may play a key role in the pathophysiology of the various aging-associated disorders. Understanding the role of the aging process in deterioration of stem cell function is crucial, not only in understanding the pathophysiology of aging-associated disorders, but also in future development of novel effective stem cell-based therapies to treat aging-associated diseases. This review article first focuses on the basis of the various aging disease-related stem cell dysfunction. It then addresses the several concepts on the potential mechanism that causes aging-related stem cell dysfunction. It also briefly discusses the current potential therapies under development for aging-associated stem cell defects.

Objective To investigate the functional role of the miR-15b/16 in vascular smooth muscle phenotypic modulation. Approach and Results We found that miR-15b/16 is the one of most abundant microRNAs expressed in contractile vascular smooth muscle cells (VSMCs). However, when contractile VSMCs convert to a synthetic phenotype miR-15b/16 expression is significantly reduced. Knocking-down endogenous miR-15b/16 in VSMCs attenuates smooth muscle-specific gene expression but promotes VSMC proliferation and migration. Conversely, over-expression of miR-15b/16 promotes smooth muscle contractile gene expression while attenuating VSMC migration and proliferation. Consistent with this, over-expression of miR-15b/16 in a rat carotid balloon injury model markedly attenuates injury-induced smooth muscle de-differentiation and neointima formation. Mechanistically, we identified the potent oncoprotein yes-associated protein (YAP) as a downstream target of miR-15b/16 in VSMCs. Reporter assays validated that miR-15b/16 targets YAP’s 3′-untranslated region. Moreover, overexpression of miR-15b/16 significantly represses YAP expression, whereas conversely, depletion of endogenous miR-15b/16 results in up-regulation of YAP expression. Conclusions These results indicate that miR-15b/16 plays a critical role in smooth muscle phenotypic modulation at least partly through targeting YAP. Restoring expression of miR-15b/16 would be a potential therapeutic approach for treatment of proliferative vascular diseases.