Investigation of treatment efficacy of coenzyme Q10 containing nanotherapeutics in coenzyme Q10 nephropathy and comparison of mitochondrial functions in in vitro model

CoQ10 deficiency caused by genetic mutations affects many organs, especially the kidneys. Among these genetic mutations, COQ8B mutations have been identified as an important cause of chronic renal failure in the adolescent age group. Oral CoQ10 supplementation at the early stage of failure can reduce proteinuria and stabilize kidney function. However, CoQ10 is a molecule with low bioavailability and high tissue distribution due to its high molecular weight and lipophilic characteristics. More effective treatment can be provided by increasing the local CoQ10 concentration in the mitochondria, and renal failure can be prevented entirely in these patients. In this study, mitochondria-targeted CoQ10 loaded PLGA-b-PEG-TPP nanoparticles (CoQ10-TPP-NPs) have been formulated to prevent/cure CoQ10 nephropathy secondary to mutations causing CoQ10 deficiency. These nanoparticles were characterized by determining surface charge, particle distribution, drug entrapment efficiency and morphological properties. CoQ10-TPP-NPs were found to have a size of approximately 150 nm and a zeta potential of +20 mV. The entrapment efficiency of the nanoparticles was determined as 40% by the HPLC method. Cytotoxicity studies with the XTT assay have shown no effect on the viability of the human kidney proximal tubule epithelial cells (HK-2) exposed to CoQ10-TPP-NPs. An in vitro disease model was developed in HK-2 cells by silencing the COQ8B gene (COQ8B-/- cell lines) with different doses of siRNA for 48 and 72 hours. According to the results of real-time polymerase chain reaction (rt-PCR) experiments, the most effective gene inhibition was obtained by 100 nM siRNA after 48 hours. This result was confirmed by Western Blot analysis. The efficacy of the formulated nanoparticles on COQ8B-/- cells was evaluated through mitochondrial functions by metabolomic analyzes. The findings have shown that the treatment of COQ8B-/- cells with CoQ10-TPP-NPs is more effective in increasing the TCA cycle rate compared to free COQ10. Keywords: CoQ10, COQ8B, polymeric nanoparticle, targeting mitochondria, metabolomics