Endoglin involvement in integrin-mediated cell adhesion as a putative pathogenic mechanism in hereditary hemorrhagic telangiectasia type 1 (HHT1)

5 p.-2 fig.Mutations in the endoglin gene (ENG) are responsible for ∼50% of all cases with hereditary hemorrhagic telangiectasia (HHT). Because of the absence of effective treatments for HHT symptoms, studies aimed at identifying novel biological functions of endoglin which could serve as therapeutic targets of the disease are needed. Endoglin is an endothelial membrane protein, whose most studied function has been its role as an auxiliary receptor in the TGF-β receptor complex. However, several lines of evidence suggest the involvement of endoglin in TGF-β-independent functions. Endoglin displays, within its zona pellucida domain, an RGD motif, which is a prototypic sequence involved in integrin-based interactions with other proteins. Indeed, we have recently described a novel role for endothelial endoglin in leukocyte trafficking and extravasation via its interaction with leukocyte integrins. In addition, functional, as well as protein and gene expression analysis have shown that ectopic endoglin represses the synthesis of several members of the integrin family and modulates integrin-mediated cell adhesions. This review focuses on the tight link between endoglin and integrins and how the role of endothelial endoglin in integrin-dependent cell adhesion processes can provide a better understanding of the pathogenic mechanisms leading to vascular lesions in endoglin haploinsufficient HHT1 patients.This study was supported by grants from the Ministerio de Economia y Competitividad of Spain (SAF2010-19222 and SAF2013-43421-R to Carmelo Bernabeu; SAF2010-1588, SAF2013-45784-R, and RD12/0021/0032-REDINREN to José M. Lopez-Novoa).Peer reviewe

Overexpression of the short endoglin isoform reduces renal fibrosis and inflammation after unilateral ureteral obstruction

33 p.-9 fig.-2 tab. Muñoz-Felix. J. M. et al.Transforming growth factor beta 1 (TGF-β1) is one of the most studied cytokines involved in renal tubulo¬interstitial fibrosis, which is characterized by myofibroblast abundance and proliferation, and high buildup of extracellular matrix in the tubular interstitium leading to organ failure. Endoglin (Eng) is a 180-kDa homodimeric transmembrane protein that regulates a great number of TGF-β1 actions in different biological processes, includ¬ing ECM synthesis. High levels of Eng have been observed in experimental models of renal fibrosis or in biopsies from patients with chronic kidney disease. In humans and mice, two Eng isoforms are generated by alternative splicing, L-Eng and S-Eng that differ in the length and composition of their cytoplasmic domains. We have previously described that L-Eng overexpression promotes renal fibrosis after unilateral ureteral obstruction (UUO). However, the role of S-Eng in renal fibrosis is unknown and its study would let us analyze the possible function of the cytoplasmic domain of Eng in this process. For this purpose, we have generated a mice strain that overexpresses S-Eng (S-ENG+) and we have performed an UUO in S-ENG+ and their wild type (WT) control mice. Our results indicate that obstructed kidney of S-ENG+ mice shows lower levels of tubulo-interstitial fibrosis, less inflammation and less interstitial cell proliferation than WT littermates. Moreover, S-ENG+ mice show less activation of Smad1 and Smad2/3 pathways. Thus, S-Eng overexpression reduces UUO-induced renal fibrosis and some associated mechanisms. As L-Eng overexpression provokes renal fibrosis we conclude that Eng-mediated induction of renal fibrosis in this model is dependent on its cytoplasmic domain.This study has been supported by grants from Ministerio de Economía y Competitividad of Spain (SAF2013-43421-R to CB; and SAF2013-45784-R to JML-N), Junta de Castilla y León (GR100, JML-N), Institute Queen Sophie for Renal Research, Fundación Renal Íñigo Álvarez de Toledo, Madrid, Spain (0016¬002), Centro de Investigación Biomédica en Red de Enfermedades Raras (CIBERER, CB) (ISCIII-CB06/07/0038) and Red de Investigación Cooperativa en Enfermedades Renales (REDINREN, JML-N) (R12/0021/ 0032). CIBERER and REDINREN are initiatives of the Instituto de Salud Carlos III (ISCIII) of Spain supported by FEDER funds. BO and ENG are supported by fellowships from Ministerio de Economía y Competitividad (BES-2011-048968 and BES-2008-005550). JMMF, LPR and CC are supported by fellowships from Junta de Castilla y León and Fondo Social Europeo (EDU/1204/2010 and EDU/1083/2013).Peer reviewe

Endoglin Regulates Cyclooxygenase-2 Expression and Activity

Jerkic, Mirjana[et alt.] 9 p.-8 fig.The endoglin heterozygous (Eng+/−) mouse, which serves as a model of hereditary hemorrhagic telangiectasia (HHT), was shown to express reduced levels of endothelial NO synthase (eNOS) with impaired activity. Because of intricate changes in vasomotor function in the Eng+/− mice and the potential interactions between the NO- and prostaglandin-producing pathways, we assessed the expression and function of cyclooxygenase (COX) isoforms. A specific upregulation of COX-2 in the vascular endothelium and increased urinary excretion of prostaglandin E2 were observed in the Eng+/− mice. Specific COX-2 inhibition with parecoxib transiently increased arterial pressure in Eng+/− but not in Eng+/+ mice. Transfection of endoglin in L6E9 myoblasts, shown previously to stimulate eNOS expression, led to downregulation of COX-2 with no change in COX-1. In addition, COX-2 promoter activity and protein levels were inversely correlated with endoglin levels, in doxycyclin-inducible endothelial cells. Chronic NO synthesis inhibition with Nω-nitro-l-arginine methyl ester induced a marked increase in COX-2 only in the normal Eng+/+ mice. Nω-nitro-l-arginine methyl ester also increased COX-2 expression and promoter activity in doxycyclin-inducible endoglin expressing endothelial cells, but not in control cells. The level of COX-2 expression following transforming growth factor-β1 treatment was less in endoglin than in mock transfected L6E9 myoblasts and was higher in human endothelial cells silenced for endoglin expression. Our results indicate that endoglin is involved in the regulation of COX-2 activity. Furthermore, reduced endoglin levels and associated impaired NO production may be responsible, at least in part, for augmented COX-2 expression and activity in the Eng+/− miceThis work was supported by grants from Ministerio de Educacion y Ciencia (SAF2001/1701 to J.M.L.-N. and SAF2004–01390 to C.B.), Fondo de Investigación Sanitaria (PI020200 to C.B.), HHT Foundation International to C.B., and by the Heart and Stroke Foundation of Canada (T5016) to M.L. M.J. was supported by a Fellowship from Instituto Reina Sofía de Investigación Nefrológica. C.P.H.V. was supported by NIH grant #P2015555 from the National Center for Research ResourcesPeer reviewe

Adenosine induces mesangial cell contraction by an A1-type receptor

Adenosine induces mesangial cell contraction by an A1-type receptor. Adenosine is known to decrease renal blood flow and glomerular filtration rate. We have tested the hypothesis that adenosine exerts contractile effects on mesangial cells. Furthermore, we have studied, using selective agonists and antagonists for adenosine, which kind of adenosine receptor, A1 or A2, is mainly implicated in this response. We also investigated whether calcium is involved in adenosine-induced mesangial cell contraction. Rat cultured mesangial cells were exposed to adenosine (10−7 to 10−3M) and the contraction was measured as changes in planar cell surface area (PCSA). Adenosine induced a time-and dose-dependent reduction of PCSA. This reduction in PCSA was prevented by incubation with the A1 blocker PD116,948 but not with the A2 blocker PD115,199. Adenosine-5′-ethylcarboxamide (NECA), an A2 agonist, did not induce significant changes in PCSA whereas N6-S-1-methyl-2-phenylethyl adenosine (S-PIA), an A1 agonist, induced a dose-dependent decrease in PCSA Adenosine-induced mesangial contraction was prevented by verapamil or by incubation in a calcium-free medium. These results suggest that adenosine induces a specific contraction of cultured rat mesangial cells that seems to be mediated by its binding to the adenosine A1-type receptor. This contraction seems to be dependent on the influx of extracellular calcium

Cardiotrophin-1 improves kidney preservation, graft function, and survival in transplanted rats

[EN]Background Cold ischemia-reperfusion injury is unavoidable during organ transplantation, and prolonged preservation is associated with poorer function recovery. Cardiotrophin-1 (CT-1) is an IL-6 family cytokine with cytoprotective properties. This preclinical study in rats tested whether CT-1 mitigates cold renal ischemia-reperfusion injury in the context of the transplantation of long-time preserved kidneys. Methods Kidneys were flushed with cold (4 degrees C) University of Wisconsin solution containing 0.2 g/mL CT-1 and stored for several periods of time at 4 degrees C in the same solution. In a second approach, kidneys were first cold-preserved for 6 hours and then were perfused with University of Wisconsin solution containing CT-1 (0, 16, 32, or 64 g/mL) and further cold-preserved. Organ damage markers were measured in the kidneys at the end of the storage period. For renal transplantation, recipient consanguineous Fischer rats underwent bilateral nephrectomy and received a previously cold-preserved (24 hours) kidney as described above. Survival and creatinine clearance were monitored over 30 days. Results Cardiotrophin-1 in perfusion and preservation fluids reduced oxidative stress markers (superoxide anion and inducible nitric oxide synthase), inflammation markers (NF-B and tumor necrosis factor-), and vascular damage (vascular cell adhesion molecule-1) and activated leukemia inhibitory factor receptor and STAT-3 survival signaling. Transplantation of kidneys cold-preserved with CT-1 increased rat survival and renal function (ie, lower plasma creatinine and higher creatinine clearance) and improved kidney damage markers after transplantation (ie, lower superoxide anion, tumor necrosis factor-, intercellular adhesion molecule-1, and vascular cell adhesion molecule-1 and higher NF-B). Conclusions Cardiotrophin-1 represents a novel therapeutic strategy to reduce ischemia-reperfusion and cold preservation injury to rescue suboptimal kidneys and, consequently, to improve the clinical outcomes of renal transplantation

The role of endoglin in post-ischemic revascularization

60 p.-5 fig.-1 tab.Following arterial occlusion, blood vessels respond by forming a new network of functional capillaries (angiogenesis), by re-organizing pre-existing capillaries through the recruitment of smooth muscle cells to generate new arteries (arteriogenesis) and by growing and remodeling pre-existing collateral arterioles into physiologically relevant arteries (collateral development). All these processes result in the recovery of organ perfusion. The importance of endoglin in post-occlusion reperfusion is sustained by several observations: i) endoglin expression is increased in vessels showing active angiogenesis/remodeling; ii) genetic endoglin haploinsufficiency in humans causes deficient angiogenesis; and iii) the reduction of endoglin expression by gene disruption or the administration of endoglin-neutralizing antibodies reduces angiogenesis and revascularization. However, the precise role of endoglin in the several processes associated with revascularization has not been completely elucidated and, in some cases, the function ascribed to endoglin by different authors is controversial. The purpose of this review is to organize in a critical way the information available for the role of endoglin in several phenomena (angiogenesis, arteriogenesis, and collateral development) associated with post-ischemic revascularization.Peer reviewe

Etiopathology of chronic tubular, glomerular and renovascular nephropathies: Clinical implications

Chronic kidney disease (CKD) comprises a group of pathologies in which the renal excretory function is chronically compromised. Most, but not all, forms of CKD are progressive and irreversible, pathological syndromes that start silently (i.e. no functional alterations are evident), continue through renal dysfunction and ends up in renal failure. At this point, kidney transplant or dialysis (renal replacement therapy, RRT) becomes necessary to prevent death derived from the inability of the kidneys to cleanse the blood and achieve hydroelectrolytic balance. Worldwide, nearly 1.5 million people need RRT, and the incidence of CKD has increased significantly over the last decades. Diabetes and hypertension are among the leading causes of end stage renal disease, although autoimmunity, renal atherosclerosis, certain infections, drugs and toxins, obstruction of the urinary tract, genetic alterations, and other insults may initiate the disease by damaging the glomerular, tubular, vascular or interstitial compartments of the kidneys. In all cases, CKD eventually compromises all these structures and gives rise to a similar phenotype regardless of etiology. This review describes with an integrative approach the pathophysiological process of tubulointerstitial, glomerular and renovascular diseases, and makes emphasis on the key cellular and molecular events involved. It further analyses the key mechanisms leading to a merging phenotype and pathophysiological scenario as etiologically distinct diseases progress. Finally clinical implications and future experimental and therapeutic perspectives are discussed

Analyzing the social factors that influence willingness to pay for the management of invasive alien species under two different strategies: eradication and prevention

This an accepted author's manuscript (AAM) version of an article published in Environmental Management, 48 (2011): 418-43

Cardiotrophin-1 opposes renal fibrosis in mice: Potential prevention of chronic kidney disease

[EN]Chronic kidney disease is characterized by tubulointerstitial fibrosis involving inflammation, tubular apoptosis, fibroblast proliferation and extracellular matrix accumulation. Cardiotrophin-1, a member of the interleukin-6 family of cytokines, protects several organs from damage by promoting survival and anti-inflammatory effects. However, whether cardiotrophin-1 participates in the response to chronic kidney injury leading to renal fibrosis is unknown. We hypothesized and assessed the potential role of cardiotrophin-1 in a mice model of tubulointerstitial fibrosis induced by unilateral ureteral obstruction (UUO). Three days after UUO, obstructed kidneys from cardiotrophin-1-/- mice show higher expression of inflammatory markers IL-1β, Cd68, ICAM-1, COX-2 and iNOs, higher activation of NF-κB, higher amount of myofibroblasts and higher severity of tubular damage and apoptosis, compared with obstructed kidneys from wild-type littermates. In a later stage, obstructed kidneys from cardiotrophin-1-/- mice show higher fibrosis than obstructed kidneys from wild-type mice. Interestingly, administration of exogenous cardiotrophin-1 prevents the increased fibrosis resulting from the genetic knockout of cardiotrophin-1 upon UUO, and supplementation of wild-type mice with exogenous cardiotrophin-1 further reduces the renal fibrosis induced by UUO. In vitro, renal myofibroblasts from cardiotrophin-1-/- mice have higher collagen I and fibronectin expression and higher NF-κB activation than wild-type cells. Cardiotrophin-1 participates in the endogenous response that opposes renal damage by counteracting the inflammatory, apoptotic and fibrotic processes. And exogenous cardiotrophin-1 is proposed as a candidate for the treatment and prevention of chronic renal fibrosis

Analysis of K-Ras Nuclear Expression in Fibroblasts and Mesangial Cells

This is an open-access article distributed under the terms of the Creative Commons Attribution License.-- et al[Background]: Ras GTPases are considered cytoplasmic proteins that must be localized to cell membranes for activation, and there are few evidences of the presence of any Ras isoform in nuclei of eukaryotic cells. [Methodology/Principal Findings]: Using conventional antibodies and inmunocytochemistry, differential centrifugation and western blot, we have observed the putative presence of K-Ras isoform in the nuclei of fibroblasts and mesangial cells. In order to avoid cross-reactions with other Ras isoforms, and using antibodies against K-Ras (R-3400, H3845-M01, sc-30) or pan-Ras (05-516, OP40) in cells that only expressed the K-Ras isoform (fibroblasts obtained from H-ras−/−,N-ras−/− mice) we also detected some nuclear positive expression. To further probe the identity of nuclear K-Ras, we have generated K-Ras knockout (K-ras−/−) embrionary fibroblasts by mating of K-ras+/− heterozygote mice. Using specific antibodies, only H- and N-Ras isoforms were observed in the cytoplasm of K-ras−/− fibroblasts. However, both K-Ras4A and K-Ras4B positive signals were detected by immunocytochemistry and Western blot with two commercial antibodies (sc-522 and sc-521 against each isoforms, respectively) in both cytoplasm and nuclei from K-ras−/− fibroblasts. [Conclusions/Significance]: We show that the presence of K-Ras4B in fibroblast nuclei, already described by other authors, is probably due to a cross-reaction of the antibody with an undetermined nucleolar protein. Although this study also shows the possible nuclear expression of K-Ras isoform in fibroblasts or in mesangial cells, it also reveals the importance of being cautious in these studies about distribution of protein isoforms due to some important limitations imposed by the unspecificity of the antibodies or contaminations in cellular preparations.This work was supported by grants from Instituto de Salud Carlos III (Ministerio de Sanidad y Consumo, CP03/00094, PI041817, PI021570 and C03/10), Comisión Interministerial de Ciencia y Tecnologí­a (BFU-2004-00285/BFI; SAF2003-04177), and Junta de Castilla y León (SA001/C05; SA029A05; GRS 167/A/07 and excellence group GR100).Peer reviewe