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Biomedical subjects

D Rodríguez Puyol

Publications and source records attributed to D Rodríguez Puyol.

7 recordsLinked to original sources
PubMed2005

[Renal aging].

Frequently underestimated, the deterioration of the renal function characteristic of the aging has very prominent clinical consequences. In the present article some aspects of the cellular and molecular biology of this process are analysed. The critical role of the oxidative stress and of TGFbeta are underlined. Determinant genetic factors are also mentioned. Such a knowledge can contribute to develop therapeutical strategies to prevent the decline of the.renal function that happens with the aging.

Age Factors↗
PubMed2003

Arg-Gly-Asp-Ser (RGDS) peptide stimulates transforming growth factor beta1 transcription and secretion through integrin activation.

Extracellular matrix (ECM) components, through specific peptide motifs such as Arg-Gly-Asp (RGD), interact with integrins and can modify the behavior of cells. Transforming growth factor-beta1 (TGF-beta1) is the main cytokine involved in the synthesis of ECM proteins. We analyzed the effect of a RGD-containing peptide, as Arg-Gly-Asp-Ser (RGDS), on the regulation of TGF-beta1 secretion in cultured human mesangial cells. We found that RGDS increased mRNA expression and secretion of TGF-beta1 by stimulating the TGF-beta1 gene promoter. This effect was dependent on the interaction of RGDS with integrins. We evaluated the signaling pathways implicated in TGF-beta1 production by analyzing the effect of RGDS on kinase-related integrins. RGDS stimulated tyrosine phosphorylation as well as integrin-linked kinase (ILK) activity. However, tyrosine kinase inhibitors did not prevent the RGDS effect. In contrast, the inhibition of ILK by cell transfection with a kinase dead-ILK completely abolished the increased TGF-beta1 secretion and promoter activity in the presence of RGDS. Thus RGDS modulates the secretion of TGF-beta1, probably through increased synthesis by interacting with integrins and activating ILK. This supports a role for ECM components in the regulation of their own secretion.

Cells, Cultured↗
PubMed1995

Regulation of inducible nitric oxide synthase expression in rat mesangial cells and isolated glomeruli.

The presence of the inducible isoform of nitric oxide synthase (iNOS) in glomerular mesangial cells facilitates the synthesis of nitric oxide (NO) after stimulation with cytokines or lipopolysaccharide (LPS). As the role of NO within the glomerulus may be important in conditions such as glomerulonephritis, we have studied the effect of dexamethasone (DX) and pirrolidine dithiocarbamate (PDTC), an inhibitor of the nuclear transcription factor, NF-kappa B activation on the induced synthesis of NO in rat mesangial cells (RMC). LPS, tumor necrosis factor-alpha (TNF-alpha) and the combination of both were able to induce NO synthesis in a dose-dependent manner as measured with the determination of NO2- levels. Treatment with LPS (10 micrograms/ml) + TNF-alpha (100 ng/ml) for eight hours was the most potent stimulus for iNOS activity. DX (1 microM) had an inhibitory effect on LPS-, TNF-alpha- and LPS + TNF-alpha-induced NO synthesis (51.2, 42.5 and 68% of inhibition, respectively). The inhibitory effect of DX was confirmed using a reporter cell bioassay, whereas cGMP was measured as a reflection of bioactive NO. DX inhibited induced NO synthesis when RMC were exposed to this agent before (16 hr of pretreatment, 75.7% inhibition) or at the same time (8 hr of cotreatment, 61.2% inhibition) as TNF-alpha + LPS but not four hours after the stimuli. Northern blot analysis showed marked blunting of mRNA expression in RMC treated with DX, in concordance with functional studies. Both actinomycin D and cycloheximide significantly inhibited NO synthesis and iNOS mRNA expression. PDTC (100 microM) was able to inhibit the iNOS activity induced by LPS and TNF-alpha independently (56.8 and 49.9% inhibition, respectively), and in combination (79.1% inhibition). PDTC (1 to 100 microM) inhibited LPS + TNF-alpha-induced NO synthesis and iNOS mRNA expression in a concentration-dependent fashion (69 to 86% inhibition of NO synthesis and 50 to 100% inhibition of mRNA expression). Addition of PDTC four hours after exposure to TNF-alpha + LPS was still able to markedly inhibit NO synthesis. The effects of DX and PDTC were also demonstrated in isolated glomeruli, where two different combinations of inductive stimuli for NO synthesis were employed. Our results establish DX and PDTC as useful tools to study the regulation of NO synthesis in the mesangial cell and glomerulus, and suggest that NF-kappa B is involved in the transcriptional regulation of iNOS in RMC.

Amino Acid Oxidoreductases↗
PubMed1993

Direct interactions between platelets and cultured rat mesangial cells.

Platelets seem to be involved in the pathogenesis of some kidney diseases, but the exact relationships between platelets and the changes in renal function are incompletely known. Mesangial cells (MC) were incubated with platelet-supernatants (PS) and cellular surface area (CSA) and myosin light-chain phosphorylation (MLCP) were measured. CSA of PS-incubated MC (PS-MC) significantly diminished, as compared to control MC (70 +/- 6% vs. 100 +/- 5%). PS induced a significant increase in MLCP with respect to control cells (150 +/- 23% vs. 100 +/- 18%). When platelets were pretreated with indomethacin, the PS-dependent contraction was abolished. Pretreatment with sulotroban (SU) or BN-52021 (BN), a thromboxane A2 (TXA2) and a platelet-activating factor (PAF) receptor blocker respectively, also completely blocked the PS effects. In other experiments, platelets were activated with thrombin (T), adding the so obtained PS to MC. Moreover, cells were also preincubated with T and then added PS. No changes in CSA were observed in either case. It may be concluded that PS contracted cultured MC, and these changes could be related to the decreased glomerular filtration rate (GFR) observed in some diseases in which platelets seem to be involved. TXA2 and PAF may be responsible for this effect. In contrast, T incubation inhibited the effect of PS, perhaps through a direct relaxing effect of T in MC.

Animals↗