Increased caveolin-1, a cause for the declined adipogenic potential of senescent human mesenchymal stem cells.

Mesenchymal stem cell (MSC) has drawn much attention in the aspect of tissue renewal and wound healing because of its multipotency. We initially observed that bone marrow-derived human MSCs (hMSCs) divided poorly and took flat and enlarged morphology after expanded in culture over a certain number of cell passage, which resembled characteristic features of senescent cells, well-studied in human diploid fibroblasts (HDFs). More interestingly, adipogenic differentiation potential of hMSCs sharply declined as they approached the end of their proliferative life span.

NF-kappaB is involved in the TNF-alpha induced inhibition of the differentiation of 3T3-L1 cells by reducing PPARgamma expression.

TNF-alpha, a trimeric cytokine, was known to inhibit differention of preadipocytes to adipocytes. In the present study, we investigated signal mediators working downstream of TNF-alpha using murine 3T3-L1 cells. TNF-alpha induced activation of both c-jun NH(2)-terminal kinase (JNK) and nuclear transcription factor-kappaB (NF-kappaB) in 3T3-L1 cells.