Thrombospondin-2 therapy ameliorates experimental glomerulonephritis via inhibition of cell proliferation, inflammation, and TGF-β activation

Abstract

We recently identified thrombospondin-2 (TSP-2) as an endogenous regulator of matrix remodelling and inflammation in experimental kidney disease by studying TSP-2-deficient mice. In this study, we asked whether systemic TSP-2 overexpression via thigh muscle transfection is able to ameliorate the time course of the anti-Thy1 glomerulonephritis model. After induction of anti-Thy1 nephritis, rats were transfected either with an overexpression plasmid for TSP-2 or lacZ as a control. Biopsies, urine, and blood samples were taken on days 1, 3, and 6 after disease induction. Muscular overexpression of TSP-2 reduced glomerular transforming growth factor (TGF)-beta activation and glomerular extracellular matrix formation as determined by collagen IV and fibronectin. In addition, activation of mesangial cells to the myofibroblast-like phenotype was also significantly decreased in TSP-2-overexpressing animals. TSP-2 overexpression inhibited both glomerular endothelial and mesangial cell proliferation, resulting in a reduced glomerular cell number and glomerular tuft area. The inflammatory response, as monitored by T cells and antigen-presenting cells, was reduced significantly by TSP-2 overexpression, but influx of macrophages was unchanged. These data demonstrate TSP-2 as a potential therapeutic agent to inhibit the glomerular proliferative and inflammatory response as well as TGF-beta activation and extracellular matrix accumulation in experimental mesangial proliferative glomerulonephritis.

Long-Term Gene Therapy with Thrombospondin 2 Inhibits TGF-β Activation, Inflammation and Angiogenesis in Chronic Allograft Nephropathy

“…In accordance to our previous short term (one week) study in an acute glomerulonephritis model [15], we now demonstrate that the apparent competition of long-term TSP-2 therapy with endogenously increased TSP-1 was able to specifically inhibit TGF-β activation in CAN as assessed at the end point 7 months after application. Furthermore, we could demonstrate marked anti-inflammatory properties during CAN decreasing renal accumulation of T-cells, B-cells and macrophages by long-term TSP-2 gene therapy.…”

“…In healthy rat kidneys, TSP-1 as well as TSP-2 staining was absent within the glomeruli and rarely found within the tubulointerstitial compartment (data not shown, see [15]). In contrast, thirty weeks after kidney transplantation remarkable TSP-1 staining could be detected within the Bowman's capsule and to a lesser extent in the glomerular tuft of glomeruli with pronounced pathological changes (Fig.…”

“…Briefly, mTSP-2 was cut from pcDNA3.1 (kindly provided by M. Streit, Department of Surgery, Massachusetts General Hospital and Harvard Medical School, Boston, USA) using Eco RI and XbaI and subsequently ligated into pUbMCS digested equally. Transfection of left and right thigh muscles with 35 µg plasmid DNA containing mouse TSP-2 or luciferase DNA (control) was performed as descibed previously [15]. For evaluation of long-term expression, the ubiquitin-driven luciferase plasmid was compared with the commercially available pGl2 vector using the transfection conditions as mentioned above.…”

“…In a recent study in an acute glomerulonephritis model in the rat we used TSP-2 gene therapy in the thigh muscle to competitively block TSP-1 mediated TGF-β activation. Hereby, TSP-2 overexpression resulted in significant reduction of TGF-β activation and subsequent matrix accumulation and inhibited the glomerular proliferative and inflammatory response [15]. In addition, hearts of TSP-2 deficient mice show either age-related or after viral infection an increased fibrotic and inflammatory response [16], [17].…”

The SGLT2 inhibitor empagliflozin ameliorates early features of diabetic nephropathy in BTBR ob/ob type 2 diabetic mice with and without hypertension

“…Harvested kidneys were fixed in Zn fixative overnight and were further processed as previously described (12). Paraffin-embedded kidneys were cut into 2-m-thick sections.…”