Identification of Periostin as a Critical Marker of Progression/Reversal of Hypertensive Nephropathy

Progression of chronic kidney disease (CKD) is a major health issue due to persistent accumulation of extracellular matrix in the injured kidney. However, our current understanding of fibrosis is limited, therapeutic options are lacking, and progressive degradation of renal function prevails in CKD patients. Uncovering novel therapeutic targets is therefore necessary

Role de la périostine dans l'insuffisance rénale chronique expérimentale

Chronic kidney disease (CKD) is a major public health problem. The aim of this study is to investigate the role of an extracellular matrix protein, called periostin that we previously identified as a marker of a chronic kidney disease. First, we confirmed that periostin is a marker of not only hypertensive nephropathy progression but also glomerular and tubulointerstitial nephropathies. Then, in order to explore the implication of periostin in renal fibrosis, we used either wild type and periostin null mice to induce tubulointerstitial nephropathy by performing an unilateral ureteral obstruction (UUO) or specific antisens to inhibit periostin expression in hypertensive nephropathy induced in Sprague Dawley rats by L-NAME. In the UUO model, comparison between wild type and periostin null mice 15 days after obstruction revealed that periostin null mice are relatively protected in terms of fibrosis, tubular alterations and inflammation. In vitro studies confirmed that periostin is induced by TGF-ß and showed that periostin induces phosphorylation of FAK, P38 and ERK1/2. In parallel, inhibition of periostin by antisens in the L-NAME model led to an improvement of renal function reflected by a lower proteinuria and a better renal histology showing less vascular hypertrophy, glomerulosclerosis, tubular dilation and perivascular fibrosis. Our results suggest that periostin is not only a marker of renal dysfunction, but is also an active mediator that should be considered as a promising therapeutic targetL insuffisance rénale chronique (IRC) est un problème majeur de santé publique. L objectif de cette thèse est d étudier le rôle de la périostine, une protéine que nous avons préalablement identifiée comme marqueur de la progression et de la régression de la néphropathie hypertensive. Dans un 1er temps, nous avons confirmé que la périostine est un marqueur de l évolution des néphropathies, non seulement hypertensives mais également glomérulaire et tubulo-interstitielle. Dans un 2nd temps, pour étudier l implication de la périostine dans la fibrose rénale, nous avons utilisé dans un premier protocole des souris sauvages (WT) et des souris invalidées pour la périostine (KO) pour induire un modèle de néphropathie tubulo-interstitielle par obstruction urétérale unilatérale (UUO) et dans un deuxième protocole, nous avons utilisé des oligonucléotides antisens spécifiques pour inhiber l expression de la périostine dans la néphropathie hypertensive induite par L-NAME chez des rats Sprague Dawley. Dans le modèle UUO, 15 j après obstruction, les souris KO étaient relativement protégées en termes d altérations tubulaires, d inflammation et de fibrose. Les études in vitro ont confirmé que la périostine est induite par le TGF-b et ont montré que la périostine activait les voies FAK, P38 et ERK1/2. Parallèlement, l inhibition de la périostine par antisens dans le modèle L-NAME a résulté en une amélioration de l histologie rénale. Ce travail suggère que la périostine n est pas seulement un marqueur de l IRC mais aussi un médiateur de l inflammation et de la fibrose rénale, soulignant ainsi l importance des approches thérapeutiques ciblant la périostine dans le traitement de l IRCPARIS-BIUSJ-Biologie recherche (751052107) / SudocSudocFranceF

Inhibition of periostin expression protects against the development of renal inflammation and fibrosis

Increased renal expression of periostin, a protein normally involved in embryonic and dental development, correlates with the decline of renal function in experimental models and patient biopsies. Because periostin has been reported to induce cell differentiation, we investigated whether it is also involved in the development of renal disease and whether blocking its abnormal expression improves renal function and/or structure. After unilateral ureteral obstruction in wild-type mice, we observed a progressive increase in the expression and synthesis of periostin in the obstructed kidney that associated with the progression of renal lesions. In contrast, mice lacking the periostin gene showed less injury-induced interstitial fibrosis and inflammation and were protected against structural alterations. This protection was associated with a preservation of the renal epithelial phenotype. In vitro, administration of TGF-β to renal epithelial cells increased the expression of periostin several-fold, leading to subsequent loss of the epithelial phenotype. Furthermore, treatment of these cells with periostin increased the expression of collagen I and stimulated the phosphorylation of FAK, p38, and ERK 42/44. In vivo delivery of antisense oligonucleotides to inhibit periostin expression protected animals from L-NAME-induced renal injury. These data strongly suggest that periostin mediates renal disease in response to TGF-β and that blocking periostin may be a promising therapeutic strategy against the development of CKD

Markers of endothelial dysfunction, epithelial mesenchymal transition and fibrosis during progression/regression of renal disease.

<p>Real-time quantitative PCR for endothelin-1 (ET1, A) and E-selectin (ESel, B) Col3A1 (C) and vimentin (D). Results are expressed as arbitrary units. Error bars represent SEM. * <i>p</i><0.05 <i>vs</i> C ; # <i>p</i><0.05 <i>vs</i> LN Reg.</p

Univariate regression analyses between kidney disease progression hallmarks (as dependent variables) and renal cortex mRNA expression of selected genes (as independent variables).

<p>All variables were log-transformed, except from Renal Blood Flow which exhibited normal distribution.</p><p>Values are r coefficients.</p>*<p><i>p</i><0.05;</p>**<p><i>p</i><0.01;</p>***<p><i>p</i><0.001.</p

Primers used for qRT-PCR.

<p>Primers used for qRT-PCR.</p

Periostin immunohistochemistry in normal human kidney (A, B), and chronic allograft nephropathy (C, D).

<p>Original magnification ×40. Periostin (E) and vimentin (F) staining on serial sections in chronic allograft nephropathy. Original magnification ×20.</p