Assessing Cellular Uptake of Exogenous Coenzyme Q10 into Human Skin Cells by X-ray Fluorescence Imaging.

X-ray fluorescence (XRF) imaging is a highly sensitive non-invasive imaging method for detection of small element quantities in objects, from human-sized scales down to single-cell organelles, using various X-ray beam sizes. Our aim was to investigate the cellular uptake and distribution of Q10, a highly conserved coenzyme with antioxidant and bioenergetic properties. Q10 was labeled with iodine (I2-Q10) and individual primary human skin cells were scanned with nano-focused beams. Distribution of I2-Q10 molecules taken up inside the screened individual skin cells was measured, with a clear correlation between individual Q10 uptake and cell size. Experiments revealed that labeling Q10 with iodine causes no artificial side effects as a result of the labeling procedure itself, and thus is a perfect means of investigating bioavailability and distribution of Q10 in cells. In summary, individual cellular Q10 uptake was demonstrated by XRF, opening the path towards Q10 multi-scale tracking for biodistribution studies.

Exosomes and the Prion Protein: More than One Truth.

Exosomes are involved in the progression of neurodegenerative diseases. The cellular prion protein (PrPC) is highly expressed on exosomes. In neurodegenerative diseases, PrPC has at least two functions: It is the substrate for the generation of pathological prion protein (PrPSc), a key player in the pathophysiology of prion diseases. On the other hand, it binds neurotoxic amyloid-beta (Aß) oligomers, which are associated with initiation and progression of Alzheimer's disease (AD). This has direct consequences for the role of exosomal expressed PrPC. In prion diseases, exosomal PrP leads to efficient dissemination of pathological prion protein, thus promoting spreading and transmission of the disease. In AD, exosomal PrPC can bind and detoxify Aß oligomers thus acting protective. In both scenarios, assessment of the state of PrPC on exosomes derived from blood or cerebrospinal fluid (CSF) may be useful for diagnostic workup of these diseases. This review sums up current knowledge of the role of exosomal PrPC on different aspects of Alzheimer's and prion disease.