Wnt/ß-catenin inhibitor pyrivinium attenuates cisplatin-induced acute kidney injury by possibly reducing platinum uptake and accumulation mediated by reduced organic cation transporter-2 expressions.

Aberrant activation of Wnt/ß-catenin induces renal dysfunction by initiating pro-apoptotic cascades, fibrosis, oxidative and inflammatory burden. This study tested the therapeutic effects of Wnt/ß-catenin inhibitor pyrvinium against cisplatin-induced acute kidney injury (AKI) in rats. Cisplatin was administered at a single dose of 5 mg/kg (i.p.) and renal cisplatin accumulation and uptake in cortical slices were determined after the fifth day by atomic absorption spectroscopy. Levels of pro-inflammatory cytokines were checked by ELISA, and organic cation transporter-2 (OCT-2) transcription and expression in renal tissue were evaluated by RT-PCR and immunohistochemical technique. Cisplatin administration produced renal dysfunction manifested as increase in serum creatinine, blood urea nitrogen, proteinuria, reduced clearance and electrolyte imbalance. Oxidative stress indices, pro-inflammatory cytokines, fibronectin, and caspase-3 activity were elevated in cisplatin-challenged rats. Moreover, increased renal OCT-2 transcription and immunostaining were detected in cisplatin kidneys which resulted in platinum accumulation. Additional docking studies depicted strong interaction between the ß-catenin and OCT-2 protein. These manifestations induced mitochondrial dysfunction, histological damage and fibrosis. Notably, Wnt/ß-catenin inhibitor pyrvinium (60 µg/kg; p.o.) treatment reduced the renal OCT-2 gene transcription causing a decline in platinum levels. Thus, the present study concludes that Wnt/ß-catenin inhibition attenuates cisplatin-induced AKI in rats, partly by down-regulating OCT-2 expression.

Evolution of ß-catenin-independent Wnt-GSK3-mTOR signalling in regulation of energy metabolism in isoproterenol-induced cardiotoxicity model.

OBJECTIVE: Isoproterenol (ISO) is widely used agent to study the effects of interventions which could prevent or attenuate the development of myocardial infarction. The sequence of pathological event's revealed that increased myocardial tissue oxygen demand and energy dysregulation exist early during Iso-induced cardiac toxicity. Later, tissue hypoxia results in increased oxidative stress, inflammation and fibrosis along with cardiac dysfunction in this model. The canonical Wnt/ß-catenin pathway has been reported to directly implicate in inducing cardiomyocyte hypertrophy and remodelling. However, less is known about the role of non-canonical Wnt signalling in cardiac diseases. METHOD: Certain evidences have suggested that the activation of Wnt could up-regulate key energy sensor and cell growth regulator mTOR (Mechanistic target of rapamycin) by inhibition of GSK-3ß mediator. RESULT: The GSK-3ß could negatively influence the mTOR activity and produce energy dysregulation during stress or hypoxic conditions. This suggests that the inhibition of GSK-3ß by Wnt signalling could up-regulate mTOR levels and thereby restore early myocardial tissue energy balance and prevent cardiac toxicity in rodents. CONCLUSION: We hereby discuss a novel therapeutic role of the ß-catenin independent, Wnt-GSK3-mTOR axis in attenuation of Iso-induced cardiotoxicity in rodents.