Inhibition of Hedgehog signaling suppresses proliferation and microcyst formation of human Autosomal Dominant Polycystic Kidney Disease cells
SCIENTIFIC REPORTS
Authors: Silva, Luciane M.; Jacobs, Damon T.; Allard, Bailey A.; Fields, Timothy A.; Sharma, Madhulika; Wallace, Darren P.; Tran, Pamela V.
Abstract
Autosomal Dominant Polycystic Kidney Disease (ADPKD) is caused by mutation of PKD1 or PKD2, which encode polycystin 1 and 2, respectively. The polycystins localize to primary cilia and the functional loss of the polycystin complex leads to the formation and progressive growth of fluid-filled cysts in the kidney. The pathogenesis of ADPKD is complex and molecular mechanisms connecting ciliary dysfunction to renal cystogenesis are unclear. Primary cilia mediate Hedgehog signaling, which modulates cell proliferation and differentiation in a tissue-dependent manner. Previously, we showed that Hedgehog signaling was increased in cystic kidneys of several PKD mouse models and that Hedgehog inhibition prevented cyst formation in embryonic PKD mouse kidneys treated with cAMP. Here, we show that in human ADPKD tissue, Hedgehog target and activator, Glioma 1, was elevated and localized to cyst-lining epithelial cells and to interstitial cells, suggesting increased autocrine and paracrine Hedgehog signaling in ADPKD, respectively. Further, Hedgehog inhibitors reduced basal and cAMP-induced proliferation of ADPKD cells and cyst formation in vitro. These data suggest that Hedgehog signaling is increased in human ADPKD and that suppression of Hedgehog signaling can counter cellular processes that promote cyst growth in vitro.
Vascular complications in autosomal dominant polycystic kidney disease
NATURE REVIEWS NEPHROLOGY
Authors: Perrone, Ronald D.; Malek, Adel M.; Watnick, Terry
Abstract
Autosomal dominant polycystic kidney disease (ADPKD) is the most common hereditary kidney disease. Relentless cyst growth substantially enlarges both kidneys and culminates in renal failure. Patients with ADPKD also have vascular abnormalities; intracranial aneurysms (IAs) are found in similar to 10% of asymptomatic patients during screening and in up to 25% of those with a family history of IA or subarachnoid haemorrhage. As the genes responsible for ADPKD-PKD1 and PKD2-have complex integrative roles in mechanotransduction and intracellular calcium signalling, the molecular basis of IA formation might involve focal haemodynamic conditions exacerbated by hypertension and altered flow sensing. IA rupture results in substantial mortality, morbidity and poor long-term outcomes. In this Review, we focus mainly on strategies for screening, diagnosis and treatment of As in patients with ADPKD. Other vascular aneurysms and anomalies including aneurysms of the aorta and coronary arteries, cervicocephalic and thoracic aortic dissections, aortic root dilatation and cerebral dolichoectasia-are less common in this population, and the available data are insufficient to recommend screening strategies. Treatment decisions should be made with expert consultation and be based on a risk benefit analysis that takes into account aneurysm location and morphology as well as patient age and comorbidities.