The transient receptor potential vanilloid 4 channel modulates uterine tone during pregnancy

The importance of gaining insight into the mechanisms underlying uterine quiescence and contractility is highlighted by the absence of an effective strategy to prevent or treat preterm labor, the greatest cause of perinatal mortality and morbidity worldwide. Although current evidence suggests that in myometrial smooth muscle cells (mSMCs) calcium homeostasis is modulated near term to promote uterine contractility, the efficacy of blocking voltage-operated calcium channels is limited by dose-related cardiovascular side effects. Thus, we considered whether uterine contractility might be modulated by calcium entry via transient receptor potential vanilloid 4 (TRPV4) channels. In mSMC, TRPV4 gene and protein expression increased with gestation, and TRPV4-mediated Ca2+ entry and contractility were increased in mSMC from pregnant compared to nonpregnant rats. Cell membrane TRPV4 expression was specifically increased, whereas the expression of β-arrestin-1 and β-arrestin-2, molecules that can sequester TRPV4 in the cytoplasm, decreased. Physical interaction of β-arrestin-2 and TRPV4 was apparent in nonpregnant, but absent in pregnant, mouse uterus. Moreover, direct pharmacologic activation of TRPV4 increased uterine contraction, but oxytocin-induced myometrial contraction was blocked by pharmacologic inhibition of TRPV4 and decreased in mice with global deletion of TRPV4. Finally, TRPV4 channel blockade prolonged pregnancy in two distinct in vivomurinemodels of preterm labor, whereas the absence of either β-arrestin-1 or β-arrestin-2 increased susceptibility to preterm labor. These data suggest that TRPV4 channel activity modulates uterine contractility and might represent a therapeutic target to address preterm labor

Nuclear Factor-κB Activation in Neonatal Mouse Lung Protects against Lipopolysaccharide-induced Inflammation

Rationale: Injurious agents often cause less severe injury in neonates as compared with adults

Rho kinase modulates postnatal adaptation of the pulmonary circulation through separate effects on pulmonary artery endothelial and smooth muscle cells

At birth, pulmonary vasodilation occurs concomitant with the onset of air-breathing life. Whether and how Rho kinase (ROCK) modulates the perinatal pulmonary vascular tone remains incompletely understood. To more fully characterize the separate and interactive effects of ROCK signaling, we hypothesized that ROCK has discrete effects on both pulmonary artery (PA): 1) endothelial cell (PAEC) nitric oxide (NO) production and contractile state; and 2) smooth muscle cell tone independent of endothelial NO synthase (eNOS) activity. To test these hypotheses, NO production and endothelial barrier function were determined in fetal PAEC under baseline hypoxia and following exposure to normoxia with and without treatment with Y-27632, a specific pharmacological inhibitor of ROCK. In acutely instrumented, late-gestation ovine fetuses, eNOS was inhibited by nitro-l-arginine infusion into the left PA (LPA). Subsequently, fetal lambs were mechanically ventilated (MV) with 100% oxygen in the absence (control period) and presence of Y-27632. In PAEC, treatment with Y-27632 had no effect on cytosolic calcium but did increase normoxia-induced NO production. Moreover, acute normoxia increased PAEC barrier function, an effect that was potentiated by Y-27632. In fetal lambs, MV during the control period had no effect on LPA flow. In contrast, MV after Y-27632 increased LPA flow and fetal arterial Po2 (PaO2) and decreased PA pressure. In conclusion, ROCK activity modulates vascular tone in the perinatal pulmonary circulation via combined effects on PAEC NO production, barrier function, and smooth muscle tone. ROCK inhibition may represent a novel treatment strategy for neonatal pulmonary vascular disease

Distinct roles for I kappa B kinases alpha and beta in regulating pulmonary endothelial angiogenic function during late lung development

Pulmonary angiogenesis is essential for alveolarization, the final stage of lung development that markedly increases gas exchange surface area. We recently demonstrated that activation of the nuclear factor kappa-B (NF kappa B) pathway promotes pulmonary angiogenesis during alveolarization. However, the mechanisms activating NF kappa B in the pulmonary endothelium, and its downstream targets are not known. In this study, we sought to delineate the specific roles for the NF kappa B activating kinases, IKK alpha and IKK beta, in promoting developmental pulmonary angiogenesis. Microarray analysis of primary pulmonary endothelial cells (PECs) after silencing IKK alpha or IKK beta demonstrated that the 2 kinases regulate unique panels of genes, with few shared targets. Although silencing IKK alpha induced mild impairments in angiogenic function, silencing IKK beta induced more severe angiogenic defects and decreased vascular cell adhesion molecule expression, an IKK beta regulated target essential for both PEC adhesion and migration. Taken together, these data show that IKK alpha and IKK beta regulate unique genes in PEC, resulting in differential effects on angiogenesis upon inhibition, and identify IKK beta as the predominant regulator of pulmonary angiogenesis during alveolarization. These data suggest that therapeutic strategies to specifically enhance IKK beta activity in the pulmonary endothelium may hold promise to enhance lung growth in diseases marked by altered alveolarization

Heads and tails of laccases in bioethanol production

In a lignocellulosic biorefinery, the sugar platform could lead to bioethanol production through biochemical routes. The bioethanol production process is, however, hindered by the recalcitrant structure of lignocellulose and a pretreatment is needed to increase biomass digestibility. Current pretreatment technologies generate inhibitory compounds that hamper the sugar conversion to ethanol by the fermenting microorganism.High ethanol titers are necessary to make the process economically-viable. This could be reached by using high substrate loadings, which implies high inhibitor concentration in the broth. Laccases are powerful biocatalysts to overcome the effect of inhibitory compounds. Laccases are multicopper oxidases that catalyze the oxidation of substituted phenols, anilines and aromatic thiols to their corresponding radicals. This capacity allows laccases to act specifically on phenolic compounds present in pretreated materials.In our studies, the potential of laccases as detoxification agents has been demonstrated by removing 70 to 100% of total phenols. Laccases trigger the fermentation of slurries non-fermentable without laccase treatment by increasing dramatically the ethanol yield (from 0.1 g/g to 0.36 g/g). The implementation of the laccase detoxification step boosts ethanol production at substrate loadings as high as 25% (w/w) reaching 58.6 g/L ethanol concentration for a cost-effective industrial ethanol production.Despite the great phenolic reduction, sugar recovery is reduced after laccase addition. Our results suggest that laccase-derived products exert a negative effect on enzymatic hydrolysis. An increase in Klason lignin together with changes observed in the ATR–FTIR spectra supported a grafting process that would limit the accessibility of cellulolytic enzymes to cellulose