Sustained Activation of Guanylate Cyclase-A with TDT, a Natriuretic Peptide Derivative, Exhibits Cardiorenal Protection in Dahl Salt-Sensitive Hypertensive Rats

Abstract

Heart failure often presents with prognosis-relevant impaired renal function. To investigate whether the chronic activation of guanylate cyclase-A (GC-A) protects both heart and kidney, we examined the effects of TDT, a neprilysin (NEP)-resistant natriuretic peptide (NP) derivative, on cardiac and renal dysfunction in Dahl salt-sensitive hypertensive (DS) rats. Pretreatment with NEP or NEP inhibitor did not influence GC-A activation by TDT both in vitro and in vivo, resulting in a long-acting profile of TDT compared with native human atrial NP (hANP). The repeated administration of TDT to DS rats suppressed the progress of cardiac hypertrophy, systolic/diastolic dysfunction, and proteinuria in a dose-dependent manner. Compared with vehicle and hANP, salt diet-induced podocyte injury was reduced by TDT, as analyzed by urinary podocalyxin concentration, renal expression of nephrin mRNA, and glomerular expression of desmin protein. Since glomerular TRPC6 plays detrimental roles in podocyte homeostasis, we examined the renal expression of TRPC6 in DS rats and found that salt diet upregulated the expression of TRPC6. Importantly, TRPC6 induction was significantly decreased in TDT-treated rats, compared with vehicle and hANP. Consistently, in primary-culture podocytes from DS rats, TDT inhibited ATP-induced calcium influx, similar to TRPC inhibitor SKF96365. Finally, TDT-mediated protection of podocytes was abolished by protein kinase G inhibitor KT5823. In conclusion, TDT treatment attenuated heart and kidney dysfunction, accompanied by podocyte protection through inhibition of TRPC6. Thus, long-acting NPs could be a new avenue for treatment of heart failure.

Pharmacokinetic and Pharmacodynamic Profiles of Glyco-Modified Atrial Natriuretic Peptide Derivatives Synthesized Using Chemo-enzymatic Synthesis Approaches

“…In vitro human GC-A (hGC-A) agonistic activity was measured in accordance with a previous report. 6 Briefly, CHO cells stably expressing hGC-A were seeded in a 384-well plate at a concentration of 4 × 10 3 cells/well and cultured for 1 d under 5% CO 2 at 37 °C. After the removal of culture medium, the cells were incubated with 1.6 mM 1-methyl-3-isobutylxanthine (Merck Millipore, Billerica, MA, USA) for 10 min, followed by incubation for 15 min with ANP or test compounds.…”

“…The plasma cGMP concentration was evaluated using 8-week-old male SD rats under isoflurane (2%) anesthesia, as described previously. 6 Compound 1 or 3 at a concentration of 100 nmol/kg was administrated via bolus intravenous injection immediately after the intravenous infusion of saline or phosphoramidon (Santa Cruz Biotechnology, Dallas, TX, USA), a NEP inhibitor, at a concentration of 825 nmol/kg/min for 2 min. This was followed by continuous administration at a concentration of 165 nmol/kg/min until the end of the experiment, as previously reported by Hashimoto et al 20 The concentration of cGMP in the Na 2 EDTA plasma at each time point was measured using an EIA kit (GE Healthcare, Little Chalfont, UK).…”

“…In vitro human GC-A (hGC-A) agonistic activity was measured in accordance with a previous report . Briefly, CHO cells stably expressing hGC-A were seeded in a 384-well plate at a concentration of 4 × 10 3 cells/well and cultured for 1 d under 5% CO 2 at 37 °C.…”

“…Oishi et al reported its potential application in the treatment of chronic heart failure, using a natriuretic peptide derivative. 6 Furthermore, a novel therapeutic potential of ANP in cancer treatment has been reported by Nojiri et al, who demonstrated that the recurrence of lung cancer after surgery was significantly lower in ANPtreated patients than in the patients who were not treated with ANP; 3 this is because of the activation of GC-A by ANP. 4 However, the current clinical use of ANP is limited to the continuous intravenous infusion owing to its short half-life (2.4 ± 0.7 min).…”

“…In Japan, an α-human ANP, carperitide, has been used as a first-line drug for acute decompensated heart failure (ADHF) over many years. Oishi et al reported its potential application in the treatment of chronic heart failure, using a natriuretic peptide derivative . Furthermore, a novel therapeutic potential of ANP in cancer treatment has been reported by Nojiri et al, who demonstrated that the recurrence of lung cancer after surgery was significantly lower in ANP-treated patients than in the patients who were not treated with ANP; this is because of the activation of GC-A by ANP .…”