Preclinical Study of DNA-Recognized Peptide Pyrrole-Imidazole Polyamide Targeting Human TGF-β1 Promoter for Progressive Renal Diseases in Common Marmoset

Abstract

Pyrrole-imidazole (PI) polyamides are novel gene silencers that strongly bind the promoter region of target genes in a sequence-specific manner to inhibit gene transcription. We developed a PI polyamide targeting human TGF-b1 (hTGF-b1). To develop PI polyamide targeting hTGF-b1 (Polyamide) as a practical medicine for progressive renal diseases, we examined the effects of Polyamide in two common marmoset models of nephropathy. We performed lead optimization of PI polyamides targeting hTGF-b1 by the dose-dependent inhibition of the PMA-stimulated expression of TGF-b1 mRNA in marmoset fibroblasts. Marmosets were housed with a 0.05% NaCl and magnesium diet and treated with cyclosporine A (CsA; 37.5 mg/kg/day, 8 weeks) to establish chronic nephropathy. Marmosets with nephropathy were treated with Polyamide (1 mg/kg/week, 4 weeks). We also established a unilateral urethral obstruction (UUO) model and examined the effects of Polyamide (1 mg/kg/week, 4 times) in marmosets. Histologically, the renal medulla from CsA-treated marmosets showed cast formation and interstitial fibrosis in the renal medulla.Immunohistochemistry showed strong staining of Polyamide in the renal medulla from CsA-treated marmosets. Polyamide treatment (1 mg/kg/week, 4 times) reduced hTGF-b1 staining and urinary protein excretion in CsA-treated marmosets. Polyamide reduced the glomerular injury score (GIS) and tubulointerstitial injury score (TIS) in UUO kidneys from marmosets. Polyamide significantly suppressed the hTGF-b1 and Snail mRNA expression in UUO kidneys from marmosets. PI polyamide effectively improved CsA-and UUO-associated nephropathy, indicating its potential application in the prevention of renal fibrosis in progressive renal diseases.