Methylation patterns of the mammalian genome are thought to be crucial for development. The precise mechanisms designating specific genomic loci for methylation are not known. Targeted deletion of Lsh results in perinatal lethality with a rather normal development. We report here, however, that Lsh −/− mice show substantial loss of methylation throughout the genome. The hypomethylated loci comprise repetitive elements and single copy genes. This suggests that global genomic methylation is not absolutely required for normal embryogenesis. Based on the similarity of Lsh to other SNF2 chromatin remodeling proteins, it suggests that alteration of chromatin affects global methylation patterns in mice.

Fike CD. NADPH oxidases and reactive oxygen species at different stages of chronic hypoxia-induced pulmonary hypertension in newborn piglets. Am J Physiol Lung Cell Mol Physiol 297: L596 -L607, 2009. First published July 10, 2009 doi:10.1152/ajplung.90568.2008.-Recently, we reported that reactive oxygen species (ROS) generated by NADPH oxidase (NOX) contribute to aberrant responses in pulmonary resistance arteries (PRAs) of piglets exposed to 3 days of hypoxia (Am J Physiol Lung Cell Mol Physiol 295: L881-L888, 2008). An objective of the present study was to determine whether NOX-derived ROS also contribute to altered PRA responses at a more advanced stage of pulmonary hypertension, after 10 days of hypoxia. We further wished to advance knowledge about the specific NOX and antioxidant enzymes that are altered at early and later stages of pulmonary hypertension. Piglets were raised in room air (control) or hypoxia for 3 or 10 days. Using a cannulated artery technique, we found that treatments with agents that inhibit NOX (apocynin) or remove ROS [an SOD mimetic (M40403) ϩ polyethylene glycol-catalase] diminished responses to ACh in PRAs from piglets exposed to 10 days of hypoxia. Western blot analysis showed an increase in expression of NOX1 and the membrane fraction of p67phox. Expression of NOX4, SOD2, and catalase were unchanged, whereas expression of SOD1 was reduced, in arteries from piglets raised in hypoxia for 3 or 10 days. Markers of oxidant stress, F 2-isoprostanes, measured by gas chromatographymass spectrometry, were increased in PRAs from piglets raised in hypoxia for 3 days, but not 10 days. We conclude that ROS derived from some, but not all, NOX family members, as well as alterations in the antioxidant enzyme SOD1, contribute to aberrant PRA responses at an early and a more progressive stage of chronic hypoxiainduced pulmonary hypertension in newborn piglets. superoxide dismutase enzymes; SOD1; SOD2; NOX4; NOX1; p67phox; catalase; F 2-isoprostanes; M40403 SCIENTIFIC AND CLINICAL ADVANCES implicate disruption of enzymatic systems that produce and regulate reactive oxygen species (ROS) in the pathogenesis of a number of vascular diseases, including pulmonary hypertension (11,37,40,53,64,65). In particular, there is growing evidence that NADPH oxidase (NOX) family members are important sources for ROS generation in vascular diseases. Yet, compared with the systemic circulation, little is known about the role of the various NOX family members in the pulmonary circulation (10,22,28,39,45,62). Even less is known about the role of NOX family members in regulating vascular tone and reactivity in the neonatal compared with the adult pulmonary circulation. Fundamental differences in the regulation of pulmonary vascular tone in newborns and adults caution against extrapolation of findings regarding NOX signaling in adult lungs to the newborn (52, 74). Regulation of vascular tone is known to differ between larger (conduit-level) pulmonary arteries and smaller (resistance-level) pulmonary arteries (PRAs) (2...

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The factors involved in estradiol-17 beta induced growth stimulation of MCF-7 human breast cancer cells have been examined. Wild type MCF-7 cells (and clone E3) were shown to undergo slow growth in phenol-red-free medium containing specific calf sera. The E3 clone was used to document a mean 6-day growth stimulation of 3.35-fold (doubling time = 33 +/- 3 h) in cultures supplemented with 10(-11) M estradiol-17 beta. The serum batch utilized in the culture medium is most important in acquiring significant growth stimulation of MCF-7 cells by estradiol-17 beta. Regardless of the absence of phenol-red, only selected sera (2 out of 14 tested) supported minimal growth of MCF-7 cells in the absence of added estradiol 17 beta (doubling time = 55 +/- 11 h). When a calf-serum-supplemented culture failed to display a complete growth response to estradiol-17 beta, it was due to the rapid growth of the cells in the control (minus estradiol-17 beta) flasks. Sera that promoted shorter doubling times for MCF-7 cells cultured in the absence of estradiol-17 beta were rendered less supportive of growth if treated with dextran-coated charcoal or when cultures were supplemented with the estrogen antagonist ICI 164,384 (10(-7) M). Pooled extracts of these sera were shown to contain stimulatory levels of estradiol-17 beta. Dextran-coated charcoal treatment of sera removed or deactivated factors (other than estradiol-17 beta) which were not only required for the growth of MCF-7 cells, but were necessary for estrogen-stimulated growth. Varying the serum-containing medium, buffer, and nutrient mix or the addition of insulin has no effect on the growth response of these cells to estradiol-17 beta. These investigations document the culture conditions required to produce a maximal and consistent proliferative effect of E2 on MCF-7 cells without exposing the serum constituent to damaging chemical or absorbent agents.

Background Type 1 diabetes mellitus (DM) patients surviving myocardial infarction (MI) manifest an increased incidence of subsequent heart failure (HF). We have previously shown that after MI, type 1 DM is associated with accentuated myocardial oxidative stress (OS) and concomitant worsening of left ventricular (LV) function. However, the precise mechanisms whereby type 1 DM-enhanced OS adversely affects HF after MI remain obscure. As carbonylation of proteins is an irreversible post-translational modification induced only by OS that often leads to the loss of function, we analyzed protein-bound carbonyls in the surviving LV myocardium of MI and DM + MI rats in relation to residual LV function. Methods Type 1 DM was induced in rats via administration of streptozotocin. Two weeks after induction of type 1 DM, MI was produced in DM and non-DM rats by coronary artery ligation. Residual LV function and remodeling was assessed at 4 weeks post-MI by echocardiography. Myocardial carbonylated proteins were detected through OxyBlot analysis, and identified by mass spectrometry. Results Compared with MI rats, DM + MI rats exhibited significantly poorer residual LV systolic function and elevated wet to dry weight ratios of the lungs. Protein carbonyl content in cardiac tissue and isolated heart mitochondria of DM + MI rats was 20% and 48% higher, respectively, versus MI rats. Anti-oxidative enzymes and fatty acid utilization proteins were among the carbonylated protein candidates identified. Conclusions These findings implicate myocardial protein carbonylation as part of the molecular pathophysiology of aggravated HF in the type 1 diabetic post-infarction heart.

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Background: Type 1 diabetes mellitus (DM) patients surviving myocardial infarction (MI) are at heightened risk for the subsequent development of heart failure (HF). Despite the worse outcomes, investigations into the pathophysiological mechanisms that contribute to the increased frequency of HF after MI in the type 1 DM heart remain scarce. Neuregulin-1 (NRG-1), along with the ErbB family of receptor tyrosine kinases through which NRG-1 ligands signal, have been shown to be intimately involved in mediating cardiac recovery after MI. However, the impact of type 1 DM on this signaling system post-MI remains to be elucidated. Therefore, in the present study, we examined myocardial NRG-1/ErbB signaling during post-MI HF in the presence of type 1 DM. Methods: Type 1 DM was induced in male Sprague-Dawley rats via a single intraperitoneal injection of streptozotocin (STZ) (65 mg/kg). Two weeks after induction of type 1 DM, MI was produced in DM and non-DM rats by ligation of the left anterior descending (LAD) coronary artery. Residual left ventricular (LV) function was assessed by echocardiography at 4 weeks post-MI. Following echocardiographic assessment, NRG-1, ErbB2, and ErbB4 protein expression was assessed in the remote, surviving LV myocardium of DM and non-DM rats using Western blot techniques. Results: LV Fractional Shortening (FS) and LV Ejection Fraction (EF) were significantly lower in the DM + MI group compared to the MI group ([LVFS: DM + MI, 17.9 ± 0.7 (n=6) vs. MI, 25.2 ± 2.2 (n=6), p <0.05; LVEF: DM + MI, 35.5 ± 1.4 (n=6) vs. MI, 47.5 ± 3.5 (n=6), p <0.05]), indicating an increased functional severity of HF in the diabetic post-MI group. The weight of myocardial scar caused by the infarction was not significantly different between the MI groups ([DM + MI, 0.19 ± 0.02 g (n=4) vs. MI, 0.20 ± 0.03 g (n=4), p =0.70]). ErbB2, ErbB4, and NRG-1 protein expression levels were all significantly lower in the DM + MI group compared to the MI group. Conclusions: These findings demonstrate that type 1 DM impairs myocardial NRG-1/ErbB signaling in response to MI, which may contribute to the accelerated progression of subsequent HF. Augmentation of NRG-1 or its downstream signaling pathways may represent a novel therapeutic strategy for ameliorating post-MI HF in the setting of type 1 DM.