A nitrozatív stressz szerepe a kardiovaszkuláris rendszer szabályozásában = Regulation of cardiovascular responses by nitrosative stress

Kimutattuk az oxidált LDL eredetu 7-ketokoleszterin PARP aktivációt okozó hatását. Kkimutattuk hogy az endotoxémia által kiváltott PARP aktivációt inzulinnal gátolni lehet, vagyis a PARP aktiváció indirekt jelenség, a hiperglikémia eredménye. A PARP enzim szerepét kimutattuk thorakoabdominális aorta okkluziót követő reperfúzióban is. A PARP gátlók előnyös hatásait kimutattuk szívelégtelenség és reperfúziós modellekben, és új biokémiai változásokat írtunk le ezen folyamatok kapcsán. Kimutattuk a PARP aktiváció jelenlétét perifériás vér lekukocitáin miokardiális infarktusban szenvedô betegekben. Kimutattuk, hogy human szívmitokondriumok nem termelnek releváns mennyiségben NO-t. Kimutattuk hogy számos olyan gyógyszermolekula, amely direkt vagy indirekt módon gátolja a PARP enzimet, kardioprotektív hatású. Kimutattuk a PARP aktiváció szerepét egy egér kontakt hiperszenzitivitás modellben. Kimutattuk a protein kináz C szerepét a PARP aktivációban. Kimutattuk a nitrozativ stressz és PARP szerepét terhességi diabeteszben. Kimutattunk egy új mitokondriális poliADPribozilációs reakcióutat. | We have demonstrated the ability of the oxidized LDL derived 7-ketocholesterol to induce PARP activation. We have demonstrated that endotoxin-induced PARP activation is the result of stress-hyperglycemia. We have demonstrated the role of PARP in the reperfusion injury associated with TAAA surgery. We have demonstrated the beneficial effects of PARP inhibitors in cardiac insufficiency and myocardial reperfusion models, and have demonstrated novel biochemical alterations associated with the PARP pathway. We have demonstrated the activation of PARP in circulating leukocytes from patients undergoing acute myocardial infarction. We have demonstrated that many drug molecules that are inhibiting PARP in a direct or indirect fashion exert cardioprotective effects in vitro. We have shown the role of PARP activation in a murine model of contact hypersensitivity. We have shown the role of PKC in the activation of PARP in vitro. We have shown the role of nitrosative stress and PARP activation in gestational diabetes in humans. We have described a new mitochondrial PARylation pathway

Effects of vitamin D3 derivative--calcitriol on pharmacological reactivity of aortic rings in a rodent PCOS model.

Abstract BACKGROUND: The aim of this study was to examine the effects of the hyperandrogenic state in dihydrotestosterone (DHT)-induced polycystic ovary syndrome (PCOS), the vascular responses to different vasoactive agents, and the modulatory role of vitamin D3. METHODS: APCOS model was induced by DHT application in 20 female Wistar rats. Ten of the DHT treated rats simultaneously received calcitriol treatment. After 10 weeks, myographs were used to test the reactivity of isolated thoracic aortic rings to norepinephrine and acetylcholine. Thereafter, the vascular rings were incubated with the NO-synthase blocker (nitro-L-arginine methyl ester) or the cyclooxygenase inhibitor (indomethacin) for 20 min, and the effects of norepinephrine and acetylcholine were re-evaluated. RESULTS: Norepinephrine-induced vasoconstriction was enhanced after DHT treatment, but this effect was attenuated by calcitriol administration. Vasorelaxation of DHT-treated thoracic aortic rings was impaired, but this could be partly reversed by calcitriol application. Impaired NO-dependent vasorelaxation in DHT-treated animals was mostly reversed by concomitant calcitriol administration, but this effect was diminished by prostanoid-dependent vasoconstriction. CONCLUSIONS: These studies show that the enhanced sensitivity to vasoconstrictors and impaired NO-dependent vasorelaxation in hyperandrogenic PCOS rats could be partially reversed by calcitriol treatment

Reduced Estradiol-Induced Vasodilation and Poly-(ADP-Ribose) Polymerase (PARP) Activity in the Aortas of Rats with Experimental Polycystic Ovary Syndrome (PCOS)

Polycystic ovary syndrome (PCOS) is a complex endocrine disorder characterized by hyperandrogenism and insulin resistance, both of which have been connected to atherosclerosis. Indeed, an increased risk of clinical manifestations of arterial vascular diseases has been described in PCOS. On the other hand endothelial dysfunction can be detected early on, before atherosclerosis develops. Thus we assumed that vascular dysfunction is also related directly to the hormonal imbalance rather than to its metabolic consequences. To detect early functional changes, we applied a novel rodent model of PCOS: rats were either sham operated or hyperandrogenism was achieved by implanting subcutaneous pellets of dihydrotestosterone (DHT). After ten weeks, myograph measurements were performed on isolated aortic rings. Previously we described an increased contractility to norepinephrine (NE). Here we found a reduced immediate relaxation to estradiol treatment in pre-contracted aortic rings from hyperandrogenic rats. Although the administration of vitamin D3 along with DHT reduced responsiveness to NE, it did not restore relaxation to estradiol. Poly-(ADP-ribose) polymerase (PARP) activity was assessed by poly-ADP-ribose immunostaining. Increased PAR staining in ovaries and circulating leukocytes from DHT rats showed enhanced DNA damage, which was reduced by concomitant vitamin D3 treatment. Surprisingly, PAR staining was reduced in both the endothelium and vascular smooth muscle cells of the aorta rings from hyperandrogenic rats. Thus in the early phase of PCOS, vascular tone is already shifted towards vasoconstriction, characterized by reduced vasorelaxation and vascular dysfunction is concomitant with altered PARP activity. Based on our findings, PARP inhibitors might have a future perspective in restoring metabolic disorders in PCOS

A novel approach of homozygous haplotype sharing identifies candidate genes in autism spectrum disorder

Autism spectrum disorder (ASD) is a highly heritable disorder of complex and heterogeneous aetiology. It is primarily characterized by altered cognitive ability including impaired language and communication skills and fundamental deficits in social reciprocity. Despite some notable successes in neuropsychiatric genetics, overall, the high heritability of ASD (~90%) remains poorly explained by common genetic risk variants. However, recent studies suggest that rare genomic variation, in particular copy number variation, may account for a significant proportion of the genetic basis of ASD. We present a large scale analysis to identify candidate genes which may contain low-frequency recessive variation contributing to ASD while taking into account the potential contribution of population differences to the genetic heterogeneity of ASD. Our strategy, homozygous haplotype (HH) mapping, aims to detect homozygous segments of identical haplotype structure that are shared at a higher frequency amongst ASD patients compared to parental controls. The analysis was performed on 1,402 Autism Genome Project trios genotyped for 1 million single nucleotide polymorphisms (SNPs). We identified 25 known and 1,218 novel ASD candidate genes in the discovery analysis including CADM2, ABHD14A, CHRFAM7A, GRIK2, GRM3, EPHA3, FGF10, KCND2, PDZK1, IMMP2L and FOXP2. Furthermore, 10 of the previously reported ASD genes and 300 of the novel candidates identified in the discovery analysis were replicated in an independent sample of 1,182 trios. Our results demonstrate that regions of HH are significantly enriched for previously reported ASD candidate genes and the observed association is independent of gene size (odds ratio 2.10). Our findings highlight the applicability of HH mapping in complex disorders such as ASD and offer an alternative approach to the analysis of genome-wide association data

A gesztációs diabétesz mellitusz súlyossága befolyásolja a három évvel a szülést követően mért mikrovaszkuláris diszfunkció mértékét, mely kapcsolatban állhat az emelkedett szisztémás oxidatív stresszel

Gesztációs diabétesz mellituszban emelkedett oxidatív-nitratív stressz, és poli(ADP-ribóz)polimeráz aktiváció van jelen, mely szerepet játszhat a későbbi élet során tapasztalt magasabb kardiovaszkuláris kockázat kialakulásában. Tanulmányunkban azt vizsgáltuk, hogy 3 évvel a szülés után, a megelőző gesztációs diabétesz súlyossága befolyásolja-e az anyák érrendszerének állapotát, valamint milyen összefüggés mutatható ki a vaszkuláris funkció romlása és az oxidatív-nitratív stressz és poli(ADP-ribóz)polimeráz aktiváció között. Korábban súlyos (inzulinnal kezelt) és enyhe (diétával kezelt) gesztációs diabéteszen átesett nők nagyartériáinak funkcióját applanációs tonometriával, a mikrokeringés reaktivitását provokációs tesztek elvégzése során lézer-Doppler módszerrel mértük. A véralkotókban mérhető oxidatív-nitratív stresszt és poli(ADP-ribóz)polimeráz aktivációt kolorimetrás valamint immunhisztokémiai technikával határoztuk meg. Inzulinnal kezelt gesztációs diabéteszben a mikrokeringés zavarát, valamint az oxidatív stressz emelkedését mutattuk ki. Eredményeink alapján az előzetesen igazolt gesztációs diabétesz súlyossága befolyásolja a kialakuló mikrovaszkuláris diszfunkció mértékét, melyet emelkedett oxidatív stressz kísér. A nitratív stressz és a poli(ADP-ribóz)polimeráz aktiváció összefüggést mutat egyes vaszkuláris paraméterekkel, bár ezek mértékét a betegség súlyossága nem befolyásolja. Kulcsszavak: gesztációs diabétesz mellitus, oxidatív stressz, utánkövetés, vaszkuláris funkci

Trascriptional regulation of human CYP27 integrates retinoid, peroxisome proliferator activated receptor, and liver X receptor signaling in macrophages

Cholesterol uptake and efflux are key metabolic processes associated with macrophage physiology and atherosclerosis. Peroxisome proliferator-activated receptor gamma (PPARgamma) and liver X receptor alpha (LXRalpha) have been linked to the regulation of these processes. It remains to be identified how activation of these receptors is connected and regulated by endogenous lipid molecules. We identified CYP27, a p450 enzyme, as a link between retinoid, PPARgamma, and LXR signaling. We show that the human CYP27 gene is under coupled regulation by retinoids and ligands of PPARs via a PPAR-retinoic acid receptor response element in its promoter. Induction of the enzyme's expression results in an increased level of 27-hydroxycholesterol and upregulation of LXR-mediated processes. Upregulated CYP27 activity also leads to LXR-independent elimination of CYP27 metabolites as an alternative means of cholesterol efflux. Moreover, human macrophage-rich atherosclerotic lesions have an increased level of retinoid-, PPARgamma-, and LXR-regulated gene expression and also enhanced CYP27 levels. Our findings suggest that nuclear receptor-regulated CYP27 expression is likely to be a key integrator of retinoic acid receptor-PPARgamma-LXR signaling, relying on natural ligands and contributing to lipid metabolism in macrophages

Transcriptional Regulation of Human CYP27 Integrates Retinoid, Peroxisome Proliferator-Activated Receptor, and Liver X Receptor Signaling in Macrophages

Cholesterol uptake and efflux are key metabolic processes associated with macrophage physiology and atherosclerosis. Peroxisome proliferator-activated receptor gamma (PPARγ) and liver X receptor alpha (LXRα) have been linked to the regulation of these processes. It remains to be identified how activation of these receptors is connected and regulated by endogenous lipid molecules. We identified CYP27, a p450 enzyme, as a link between retinoid, PPARγ, and LXR signaling. We show that the human CYP27 gene is under coupled regulation by retinoids and ligands of PPARs via a PPAR-retinoic acid receptor response element in its promoter. Induction of the enzyme's expression results in an increased level of 27-hydroxycholesterol and upregulation of LXR-mediated processes. Upregulated CYP27 activity also leads to LXR-independent elimination of CYP27 metabolites as an alternative means of cholesterol efflux. Moreover, human macrophage-rich atherosclerotic lesions have an increased level of retinoid-, PPARγ-, and LXR-regulated gene expression and also enhanced CYP27 levels. Our findings suggest that nuclear receptor-regulated CYP27 expression is likely to be a key integrator of retinoic acid receptor-PPARγ-LXR signaling, relying on natural ligands and contributing to lipid metabolism in macrophages

Estradiol dependent vasorelaxation is weaker in experimental PCOS.

<p>Rats were treated with DHT for 70 days +/− vitamin D₃ when they were sacrificed and aorta rings were isolated for myography studies. Specimens were first precontracted with norepinephrine (5×10⁻⁸ M) and then treated with two different doses of estradiol as shown. Vasodilation is expressed as a percentage of difference between maximally contracted and maximally dilated tone of the vessels according to the following equation (percentage =  (tension after norepinephrine-tension after estradiol)/(tension after norepinephrine-baseline tension) * 100). The difference between control and DHT (# = p<0.01) or control vs. DHT+ D₃ animals (+ = p<0.01) were both significant. The difference between DHT and DHT+ D₃ was not significant.</p