-
[show abstract]
[hide abstract]
ABSTRACT: BACKGROUND & AIMS: Statins improve hepatic endothelial function and liver fibrosis in experimental models of cirrhosis, thus they have been proposed as therapeutic options to ameliorate portal hypertension syndrome. The transcription factor kruppel-like factor 2 (KLF2) may be induced by statins in liver Sinusoidal Endothelial Cells (SEC) orchestrating an efficient vasoprotective response. The present study aimed to characterize whether KLF2 mediates statins-derived hepatic protection. METHODS: a) Expression of KLF2 and its vasoprotective target genes was determined in SEC freshly isolated from control or CCl(4)-cirrhotic rats treated with four different statins (atorvastatin, mevastatin, simvastatin and lovastatin), in the presence of mevalonate (or vehicle), under static or controlled shear stress conditions. b) KLF2-derived vasoprotective transcriptional programs were analyzed in SEC transfected with siRNA for KLF2 or siRNA-control and incubated with simvastatin. Paracrine effects of SEC highly-expressing KLF2 on the activation status of rat and human hepatic stellate cells (HSC) were evaluated. RESULTS: Statins administration to SEC induced significant up-regulation of KLF2 expression. KLF2 up-regulation was observed after 6h of treatment, and was accompanied by induction of its vasoprotective programs. Simvastatin vasoprotection was inhibited in the presence of mevalonate, and was magnified in cells cultured under physiological shear stress conditions. Statin-dependent induction of vasoprotective genes was not observed when KLF2 expression was muted with siRNA. SEC overexpressing KLF2 induced quiescence of HSC through a KLF2-nitric oxide-guanylate cyclase mediated paracrine mechanism. CONCLUSIONS: Upregulation of hepatic endothelial KLF2-derived transcriptional programs by statins confers vasoprotection and stellate cells de-activation, reinforcing the therapeutic potential of these drugs for liver diseases that course with endothelial dysfunction.
Journal of Hepatology 09/2012; · 9.26 Impact Factor
-
[show abstract]
[hide abstract]
ABSTRACT: Pathophysiological alterations in the endothelial phenotype result in endothelial dysfunction. Flow cessation, occurring during organ procurement for transplantation, triggers the endothelial dysfunction characteristic of ischemia/reperfusion injury, partly due to a reduction in the expression of the vasoprotective transcription factor Kruppel-like Factor 2 (KLF2). We aimed at (1) characterizing the effects of flow cessation and cold storage on hepatic endothelial phenotype, and (2) ascertaining if the consequences of cold stasis on the hepatic endothelium can be pharmacologically modulated, improving liver graft function. Expression of KLF2 and its vasoprotective programs was determined in (i) hepatic endothelial cells (HEC) incubated under cold storage conditions with or without the KLF2-inducer simvastatin, and (ii) rat livers not cold stored or preserved in cold University of Wisconsin solution (UWS) supplemented with simvastatin or its vehicle. In addition, upon warm reperfusion hepatic vascular resistance, endothelial function, nitric oxide vasodilator pathway, apoptosis, inflammation, and liver injury were evaluated in not cold stored livers or livers preserved in cold UWS supplemented with simvastatin or vehicle. Expression of KLF2 and its vasoprotective programs decrease in HEC incubated under cold storage conditions. Cold-stored rat livers exhibit a time-dependent decrease in KLF2 and its target genes, liver injury, increased hepatic vascular resistance, and endothelial dysfunction. The addition of simvastatin to the storage solution, maintained KLF2-dependent vasoprotective programs, prevented liver damage, inflammation, and oxidative stress and improved endothelial dysfunction. CONCLUSION: Our results provide a rationale to evaluate the beneficial effects of a vasoprotective preservation solution on human liver procurement for transplantation.
Hepatology 03/2012; 55(3):921-30. · 11.66 Impact Factor
-
[show abstract]
[hide abstract]
ABSTRACT: Peroxisome proliferator-activated receptor α (PPARα) is a transcription factor activated by ligands that regulates genes related to vascular tone, oxidative stress, and fibrogenesis, pathways implicated in the development of cirrhosis and portal hypertension. This study aims at evaluating the effects of PPARα activation with fenofibrate on hepatic and systemic hemodynamics, hepatic endothelial dysfunction, and hepatic fibrosis in CCl(4)-cirrhotic rats.
Mean arterial pressure (MAP), portal pressure (PP), and portal blood flow (PBF) were measured in cirrhotic rats treated with oral fenofibrate (25mg/kg/day, n=10) or its vehicle (n=12) for 7 days. The liver was then perfused and dose-relaxation curves to acetylcholine (Ach) were performed. We also evaluated Sirius Red staining of liver sections, collagen-I mRNA expression, and smooth muscle actin (α-SMA) protein expression, cyclo-oxygenase-1 (COX-1) protein expression, and cGMP levels in liver homogenates, and TXB(2) production in perfusates. Nitric oxide (NO) bioavailability and eNOS activation were measured in hepatic endothelial cells (HEC) isolated from cirrhotic rat livers.
CCl(4) cirrhotic rats treated with fenofibrate had a significantly lower PP (-29%) and higher MAP than those treated with vehicle. These effects were associated with a significant reduction in hepatic fibrosis and improved vasodilatory response to acetylcholine. Moreover, a reduction in COX-1 expression and TXB(2) production in rats receiving fenofibrate and a significant increase in NO bioavailability in HEC with fenofibrate were observed.
PPARα activation markedly reduced PP and liver fibrosis and improved hepatic endothelial dysfunction in cirrhotic rats, suggesting it may represent a new therapeutic strategy for portal hypertension in cirrhosis.
Journal of Hepatology 01/2012; 56(5):1033-9. · 9.26 Impact Factor
-
Marianna Colamaio,
Eleonora Borbone, Lucia Russo,
Mimma Bianco,
Antonella Federico,
Daniela Califano,
Gennaro Chiappetta,
Pierlorenzo Pallante,
Giancarlo Troncone,
Sabrina Battista,
Alfredo Fusco
[show abstract]
[hide abstract]
ABSTRACT: Well-differentiated thyroid carcinomas include papillary (PTC) and follicular (FTC) carcinomas. FTC is usually a more aggressive form of cancer than the more common papillary type. miR-191 expression is frequently altered in several neoplasias, being up-regulated in some cases, such as pancreatic carcinomas, and down-regulated in other carcinomas, such as melanomas.
The objective was to evaluate the expression and the role of miR-191 in thyroid carcinogenesis.
The expression of miR-191 was analyzed in tissues from patients with follicular adenoma (n = 24), FTC (n = 24), PTC (n = 15), anaplastic thyroid carcinoma (n = 8), and the follicular variant of PTC (n = 6) compared with normal thyroid tissues by quantitative RT-PCR. miR-191 expression was restored in the follicular thyroid cell line WRO, and the effects on cell proliferation, migration, and target expression were evaluated.
miR-191 is down-regulated in follicular adenoma, FTC, and follicular variant of PTC. We identified CDK6, a serine-threonine kinase involved in the control of cell cycle progression, as a novel target of miR-191. Restoration of miR-191 expression in WRO cells reduces cell growth and migration rate on vitronectin. CDK6 overexpression, correlated with miR-191 down-regulation, was found in follicular adenoma and FTC, suggesting a role of miR-191 down-regulation in the generation of these neoplasias.
Our results suggest that miR-191 down-regulation plays a role in thyroid neoplasias of the follicular histotype, likely by targeting CDK6.
The Journal of clinical endocrinology and metabolism 09/2011; 96(12):E1915-24. · 6.50 Impact Factor
-
[show abstract]
[hide abstract]
ABSTRACT: The transcription factor Kruppel-like factor 2 (KLF2) modulates the expression of multiple endothelial vasoprotective genes. In the absence of KLF2, the endothelial phenotype becomes dysfunctional. To date, blood-derived shear stress is the main physiological stimulus identified to trigger and sustain endothelial KLF2 expression. Portal hypertension is a common complication of cirrhosis. Sinusoidal distortion and endothelial dysfunction play a significant role in its pathogenesis. This study aimed to assess whether abnormal intrahepatic haemodynamics in cirrhosis could modify KLF2 expression and consequently its downstream transcriptional programmes.
Rats received carbon tetrachloride or vehicle for two (acute injury), six (early cirrhosis) and twelve weeks (advanced cirrhosis). Systemic and hepatic haemodynamic parameters were measured in vivo. Hepatic expression of KLF2 and its vasoprotective targets were determined. Additionally, KLF2 expression was determined in liver sections, in freshly-isolated hepatic endothelial cells, and in livers from simvastatin-treated cirrhotic animals.
Cirrhotic livers have increased endothelial KLF2 expression compared with controls. KLF2 elevation, observed at six weeks of cirrhosis induction, was accompanied by a parallel increase in portal pressure and an increase in the expression of its target genes eNOS, thrombomodulin and CNP. Simvastatin administration further increased hepatic KLF2 and target genes expression.
This study shows an increase in the expression of the vasoprotective transcription factor KLF2 in the cirrhotic liver, accompanied by an activation of its downstream transcriptional programmes. These data suggest that the marked increase in KLF2 expression may represent an endothelial compensatory mechanism to improve the ongoing vascular dysfunction in the cirrhotic liver.
Gut 11/2010; 60(4):517-24. · 10.11 Impact Factor
-
Rosa Visone, Lucia Russo,
Pierlorenzo Pallante,
Ivana De Martino,
Angelo Ferraro,
Vincenza Leone,
Eleonora Borbone,
Fabio Petrocca,
Hansjuerg Alder,
Carlo Maria Croce,
Alfredo Fusco
[show abstract]
[hide abstract]
ABSTRACT: We have recently reported that MicroRNAs (miR)-221 and miR-222 were up-regulated in human thyroid papillary carcinomas in comparison with the normal thyroid tissue. Bioinformatic analysis proposed the p27(Kip1) protein, a key regulator of cell cycle, as a candidate target for the miR-221/222 cluster. Here, we report that the enforced expression of miR-221 and miR-222 was able to reduce p27(Kip1) protein levels in thyroid carcinoma and HeLa cells in the absence of significant changes in specific p27(Kip1) mRNA levels. This effect is direct as miR-221 and miR-222 negatively regulate the expression of the 3'-untranslated region-based reporter construct from the p27(Kip1) gene, and is dependent on two target sites in this region. Consistent with these results, an enforced expression of the miR-221 and miR-222 induced the thyroid papillary carcinoma cell line (TPC-1) to progress to the S phase of the cell cycle. It is likely that the negative regulation of p27(Kip1) by miR-221 and miR-222 might also have a role in vivo since we report an inverse correlation between miR-221 and miR-222 up-regulation and down-regulation of the p27(Kip1) protein levels in human thyroid papillary carcinomas. Therefore, the data reported here demonstrate that miR-221 and miR-222 are endogenous regulators of p27(Kip1) protein expression, and thereby, the cell cycle.
Endocrine Related Cancer 10/2007; 14(3):791-8. · 4.36 Impact Factor
