Unveiling a common mechanism of apoptosis in β-cells and neurons in Friedreich's ataxia

M Igoillo-Esteve, E Gurgul-Convey, A Hu… - Human molecular …, 2015 - academic.oup.com
M Igoillo-Esteve, E Gurgul-Convey, A Hu, L Romagueira Bichara Dos Santos, B Abdulkarim…
Human molecular genetics, 2015academic.oup.com
Friedreich's ataxia (FRDA) is a neurodegenerative disorder associated with cardiomyopathy
and diabetes. Effective therapies for FRDA are an urgent unmet need; there are currently no
options to prevent or treat this orphan disease. FRDA is caused by reduced expression of
the mitochondrial protein frataxin. We have previously demonstrated that pancreatic β-cell
dysfunction and death cause diabetes in FRDA. This is secondary to mitochondrial
dysfunction and apoptosis but the underlying molecular mechanisms are not known. Here …
Abstract
Friedreich's ataxia (FRDA) is a neurodegenerative disorder associated with cardiomyopathy and diabetes. Effective therapies for FRDA are an urgent unmet need; there are currently no options to prevent or treat this orphan disease. FRDA is caused by reduced expression of the mitochondrial protein frataxin. We have previously demonstrated that pancreatic β-cell dysfunction and death cause diabetes in FRDA. This is secondary to mitochondrial dysfunction and apoptosis but the underlying molecular mechanisms are not known. Here we show that β-cell demise in frataxin deficiency is the consequence of oxidative stress-mediated activation of the intrinsic pathway of apoptosis. The pro-apoptotic Bcl-2 family members Bad, DP5 and Bim are the key mediators of frataxin deficiency-induced β-cell death. Importantly, the intrinsic pathway of apoptosis is also activated in FRDA patients' induced pluripotent stem cell-derived neurons. Interestingly, cAMP induction normalizes mitochondrial oxidative status and fully prevents activation of the intrinsic pathway of apoptosis in frataxin-deficient β-cells and neurons. This preclinical study suggests that incretin analogs hold potential to prevent/delay both diabetes and neurodegeneration in FRDA.
Oxford University Press