440 publications from this institution
Renal fibrosis, irrespective of its etiology, is a final common stage of almost all chronic kidney diseases. Increased apoptosis, epithelial-to-mesenchymal transition, and inflammatory cell infiltration characterize the injured kidney. On the molecular level, transforming growth factor- β 1 (TGF- β 1)-Smad3 signaling pathway plays a central role in fibrotic kidney disease. Recent findings indicate the prominent role of microRNAs, small noncoding RNA molecules that inhibit gene expression through the posttranscriptional repression of their target mRNAs, in different pathologic conditions, including renal pathophysiology. miR-21 was also shown to play a dynamic role in inflammatory responses and in accelerating injury responses to promote organ failure and fibrosis. Understanding the cellular and molecular bases of miR-21 involvement in the pathogenesis of kidney diseases, including inflammatory reaction, could be crucial for their early diagnosis. Moreover, the possibility of influencing miR-21 level by specific antagomirs may be considered as an approach for treatment of renal diseases.
The pleiotropic effects of statins, inhibitors of 3-hydroxy-3-methylglutaryl-coenzyme A (HMG-CoA) reductase, have been recently extended to the modulation of angiogenesis. Here, to get more insight into the statins action, the authors have investigated the effect of atorvastatin on the expression of several angiogenic and inflammatory genes in human umbilical endothelial cells (HUVECs). Atorvastatin was proangiogenic at the dose of 10 nM, and antiangiogenic at the concentrations of 1 to 10 micro M. Moreover, these higher concentrations inhibited also the proliferation of HUVECs induced by vascular endothelial growth factor (VEGF). Lower doses of atorvastatin did not influence endothelial cell proliferation. Importantly, atorvastatin at the micromolar concentrations diminished the production of interleukin (IL)-8, a proinflammatory and proangiogenic chemokine, and inhibited the synthesis of urokinase plasminogen activator (uPA), a potent proinflammatory mediator. However, it decreased also the expression of plasminogen activator inhibitor-1 (PAI-1) and thrombospondin-1 (TSP-1), the inhibitors of angiogenesis. Atorvastatin stimulated the expression of angiopoietin (Ang)-2 and moderately enhanced the expression of endothelial nitric oxide synthase (eNOS), whereas heme oxygenase-1 (HO-1) was not significantly affected. In conclusion, the present findings points to other angiogenesis-related effects of atorvastatin, which may be of relevance to the beneficial influence of statins in cardiovascular system.
LAMA2-related muscular dystrophy (LAMA2-MD) results from mutations in LAMA2 gene, encoding laminin α-2. It is a congenital disease characterized by muscle wasting, with the most severe version being diagnosed within first few months after birth. To generate LAMA2-DM in vitro model, we excised exon 3 from the LAMA2 gene in our previously derived healthy human induced pluripotent stem cells (hiPSCs). Obtained hiPSCs show expression of pluripotency markers, differentiation capacity into all three germ layers, normal karyotype and lack of LAMA2 expression on mRNA and protein level after differentiation into skeletal myocytes. Accordingly, it may provide novel insight into the molecular basis of LAMA2-MD.
Several studies have already demonstrated that oxidized- LDL decreases nitric oxide (NO) generation by cytokine-stimulated macrophages. However, the mechanisms of such an inhibition have not been yet elucidated. NO generation by inducible nitric oxide synthase (iNOS) is dependent on the presence of cofactors for NO generation, tetrathydrobiopterin (BH4) among them. The NO generation by these cells is also regulated by some endogenous inhibitors, like TGF-beta. Therefore, the aim of our recent study was to investigate the influence of ox-LDL on the expression of iNOS and GTP cyclohydrolase I (GTP-CH I), the key enzyme involved in the BH4 synthesis as well as the ox-LDL effect on TGF-beta expression in rat macrophages stimulated with IFNgamma (250 U/ml) and LPS (500 ng/ml). Macrophages, activated in this way, express iNOS, GTP-CH I, and TGF-beta mRNA. This expression was inhibited when the macrophages were preincubated for 24 hours with ox-LDL (100 microg/ml). Quantitative PCR revealed about 10-fold inhibition of iNOS gene expression by ox-LDL. As a consequence of down-regulation of iNOS and GTP-CH I genes, almost 3-fold diminished generation of NO2- by rat macrophages was observed. An inhibition of the TGFbeta mRNA expression was also found. Our studies indicate that decreased NO generation by ox-LDL treated macrophages may be the result of the diminished expression of both iNOS and GTP-CH I genes. This effect may be mediated by the activity of certain endogenous inhibitors of gene expression, however, our studies exclude the TGF-beta as a candidate for this activity.
Terapia genowa to metoda leczenia, w której lekiem jest kwas nukleinowy. Najczęściej jest nim prawidłowa postać genu dostarczana do komórek pacjenta za pomocą odpowiednich nośników, czyli wektorów. W terapii genowej podaje się także chorym dodatkowe kopie genów pracujących niewydajnie lub też hamuje ekspresję genów nadmiernie czynnych. W tym drugim przypadku stosuje się niekodujące białek fragmenty kwasów nukleinowych, takie jak oligonukleotydy antysensowe, rybozymy, pułapki oligonukleotydowe czy też ostatnio małe interferujące cząsteczki RNA. Od terapii genowej oczekiwano wiele, obawiano się jej i dlatego poddawano i poddaje bardzo ostrym regulacjom, surowszym aniżeli w przypadku klasycznych terapii farmakologicznych. W niniejszym referacie zwrócę uwagę na nieproporcjonalność stosowanych ograniczeń do ryzyka związanego z terapią genową, które nie jest większe niż w innych metodach leczenia. Przedyskutuję także problem efektów ubocznych, jakie pojawiły się ostatnio w wyniku skutecznej terapii genowej w złożonym niedoborze odporności i przedstawię problemy etyczne, związane ze stosowaniem tej strategii leczenia.
No abstract available.
Hypoxia, cytokines, and nitric oxide (NO) stimulate the generation of vascular endothelial growth factor (VEGF) and induce heme oxygenase-1 (HO-1) expression in vascular tissue. HO-1 degrades heme to carbon monoxide (CO), iron, and biliverdin, the latter being reduced to bilirubin by biliverdin reductase. In the present study, we investigated the role of HO-1 in the modulation of VEGF synthesis in rat vascular smooth muscle cells (VSMC). In VSMC stimulated with cytokines, inhibition of NO production significantly, but not completely, reduced VEGF release. In contrast, inhibition of HO activity by tin protoporphyrin IX (SnPPIX) totally prevented cytokine-induced increase in VEGF, despite an augmented synthesis of intracellular NO. Stimulation of HO-1 activity by hemin enhanced VEGF production; this effect was abrogated by blockade of the HO pathway. Similarly, VEGF synthesis induced by hypoxia was down-regulated by SnPPIX, but not by inhibitors of NO synthase. To elucidate further a direct involvement of HO-1 in the observed effects, we generated transfected cells that overexpressed the HO-1 gene. Notably, these cells synthesized significantly more VEGF protein than cells transfected with a control gene. Among the products of HO-1, biliverdin and bilirubin showed no effect, whereas iron ions inhibited VEGF synthesis. Exposure of cells to 1% CO resulted in a marked accumulation of VEGF (20-fold increase) over the basal level. Our data indicate that HO-1 activity influences the generation of VEGF in VSMC in both normoxic and hypoxic conditions. As CO and iron, respectively the inducer and the inhibitor of VEGF synthesis, are concomitantly produced during the degradation of heme, these data indicate that HO by-products may differentially modulate VEGF production.
