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

Identification of Pharmacological Modulators of HMGB1-Induced Inflammatory Response by Cell-Based Screening

High mobility group box 1 (HMGB1), a highly conserved, ubiquitous protein, is released into the circulation during sterile inflammation (e.g. arthritis, trauma) and circulatory shock. It participates in the pathogenesis of delayed inflammatory responses and organ dysfunction. While several molecules have been identified that modulate the release of HMGB1, less attention has been paid to identify pharmacological inhibitors of the downstream inflammatory processes elicited by HMGB1 (C23-C45 disulfide C106 thiol form). In the current study, a cell-based medium-throughput screening of a 5000+ compound focused library of clinical drugs and drug-like compounds was performed in murine RAW264.7 macrophages, in order to identify modulators of HMGB1-induced tumor-necrosis factor alpha (TNFα) production. Clinically used drugs that suppressed HMGB1-induced TNFα production included glucocorticoids, beta agonists, and the anti-HIV compound indinavir. A re-screen of the NIH clinical compound library identified beta-agonists and various intracellular cAMP enhancers as compounds that potentiate the inhibitory effect of glucocorticoids on HMGB1-induced TNFα production. The molecular pathways involved in this synergistic anti-inflammatory effect are related, at least in part, to inhibition of TNFα mRNA synthesis via a synergistic suppression of ERK/IκB activation. Inhibition of TNFα production by prednisolone+salbutamol pretreatment was also confirmed in vivo in mice subjected to HMGB1 injection; this effect was more pronounced than the effect of either of the agents administered separately. The current study unveils several drug-like modulators of HMGB1-mediated inflammatory responses and offers pharmacological directions for the therapeutic suppression of inflammatory responses in HMGB1-dependent diseases. © 2013 Gerö et al

Sustained hyperosmolarity increses TGF-beta1 and Egr-1 expression in the rat renal medulla.

BACKGROUND: Although TGF-ss and the transcription factor Egr-1 play an important role in both kidney fibrosis and in response to acute changes of renal medullary osmolarity, their role under sustained hypo- or hyperosmolar conditions has not been elucidated. We investigated the effects of chronic hypertonicity and hypotonicity on the renal medullary TGF-ss and Egr-1 expression. METHODS: Male adult Sprague Dawley rats (n = 6/group) were treated with 15 mg/day furosemide, or the rats were water restricted to 15 ml/200 g body weight per day. Control rats had free access to water and rodent chow. Kidneys were harvested after 5 days of treament. In cultured inner medullary collecting duct (IMCD) cells, osmolarity was increased from 330 mOsm to 900 mOsm over 6 days. Analyses were performed at 330, 600 and 900 mOsm. RESULTS: Urine osmolarity has not changed due to furosemide treatment but increased 2-fold after water restriction (p < 0.05). Gene expression of TGF-ss and Egr-1 increased by 1.9-fold and 7-fold in the hypertonic medulla, respectively (p < 0.05), accompanied by 6-fold and 2-fold increased c-Fos and TIMP-1 expression, respectively (p < 0.05) and positive immunostaining for TGF-ss and Egr-1 (p < 0.05). Similarly, hyperosmolarity led to overexpression of TGF-ss and Egr-1 mRNA in IMCD cells (2.5-fold and 3.5-fold increase from 330 to 900 mOsm, respectively (p < 0.05)) accompanied by significant c-Fos and c-Jun overexpressions (p < 0.01), and increased Col3a1 and Col4a1 mRNA expression. CONCLUSION: We conclude that both TGF-ss and Egr-1 are upregulated by sustained hyperosmolarity in the rat renal medulla, and it favors the expression of extracellular matrix components

Additional file 1: of Sustained hyperosmolarity increses TGF-ß1 and Egr-1 expression in the rat renal medulla

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HMGB1 induces time-dependent caspase activation in RAW 264.7 macrophages.

<p>RAW 264.7 cells were exposed to HMGB1 (5 µg/ml) for 24, 48 or 72 hours. Activated Caspase-3 was detected in cell extracts by Western blotting. Tubulin was used for loading control. The graph shows relative Caspase-3 activation values, normalized to tubulin. (**p<0.01 shows significant caspase activation compared to vehicle-treated cells).</p

Inhibition of the HMGB-induced TNFα production by catecholamines and glucocorticoids <i>in vivo</i>.

<p>Balb/c male mice (Charles River Laboratories) were injected with 0.5 mg/kg HMGB1 in the presence of 60 min pretreatment of either vehicle, or 20 mg/kg prednisolone, 10 mg/kg salbutamol, the combination of prednisolone and salbutamol (doses as above), or the glucocorticoid receptor blocker mifepristone (30 mg/kg) or the β-receptor antagonist propranolol (10 mg/kg). At 8 hours after HMGB1 injection, animals were sacrificed and serum levels of TNFα were measured. ^#p<0.05 represents a significant increase in TNFα serum levels in response to HMGB1; *p<0.05 represents significant inhibition of HMGB1-induced TNFα production by the various pharmacological agents indicated. n = 7 animals per group.</p