Abstract:
Background The mitochondrial enzyme 17 beta-hydroxysteroid dehydrogenase type 10 (HSD10) is implicated in neurodegenerative disorders, particularly Alzheimer's disease (AD), through its interplay with the amyloid-beta peptide (A beta). However, its independent pathological role in AD remains unclear. Methods To explore the individual effects of HSD10 and amyloid precursor protein (APP) overexpression (including the A beta 42-generating APP(Swe/Ind) variant), monoclonal HEK293 cell lines were developed. Cellular fitness was evaluated by measuring ATP levels, cell viability, and cytotoxicity measurements under glucose and galactose culture conditions. Mitochondrial metabolic changes were analysed using mitochondrial electron flow measurements in response to various metabolic substrates. HSD10 enzymatic activity was monitored using a fluorogenic probe, and two HSD10 inhibitors were tested for their ability to reduce cytotoxic effects. Statistical significance was determined using appropriate tests as detailed in the methods section. Results The overexpression of HSD10 or APP(Swe/Ind) led to mitochondrial dysfunction and reduced viability, particularly under glucose-deprived conditions. HSD10-driven cytotoxicity was linked to its enzymatic activity and associated with impaired TCA cycle function, reduced beta-oxidation, and increased oxidative stress. In contrast, APP(Swe/Ind) overexpression induced A beta 42 production, glucose hypermetabolism, and enhanced beta-oxidation. A beta 42 also affected HSD10 activity and further amplified its cytotoxic effects. The benzothiazole-based HSD10 inhibitor 34 restored cell viability under both HSD10 overexpression and A beta 42-rich conditions. Conclusions HSD10 and A beta 42 each contribute to mitochondrial impairment via distinct metabolic pathways. These findings established HSD10 as an independent pathological factor in AD and support the potential of HSD10 inhibitors, particularly inhibitor 34, as therapeutic agents targeting mitochondrial dysfunction in AD.
