Human Endogenous Retrovirus W Activity in Cartilage of Osteoarthritis Patients
Detection of dsRNA and syncytin-1 in chondrocyte cultures obtained from OA patients by IEM. (a) IEM on samples from OA patients. Panels A and A′: cryo-IEM shows the presence of syncytin in the nucleus and cytoplasm (arrow heads). CP: cytoplasm; CM: nuclear membrane; MT: mitochondrion; n: nucleus. Panels B and B′: detection of dsRNA. Panel C illustrates that dsRNA (small dots) and syncytin (large dots) colocalize. (b) Cryo-IEM of virus dsRNA in early or non-OA patients (ACI). Panel A shows a completely negative sample and represents two out of five tested chondrocyte cultures. Panel B: example of very low levels of dsRNA detected in chondrocyte culture of a non-OA patient. Panel C: chondrocyte culture from one of the non-/early OA patients expressed relatively high levels of dsRNA. The insert depicts structures resembling virus budding (marked with an asterisk). (c) Western blot performed on lysates prepared from chondrocytes isolated from OA patients. The expression of syncytin-1 was monitored using syncytin-1 specific antibodies. A band of ~55 kDa which corresponds to the theoretic molecular mass of syncytin-1 is visible in all lysates. Lane 1: protein marker (in kDa); lanes 2–6: chondrocyte lysates.
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