Figure 6

Schematic of mitochondrial pattern of apoptosis in type II Nucleus pulposus cells. 1. Caspase-9 activation via cross talk from Fas-receptor and caspase-8 induced Bid-T-Bid induction of cytochrome c release by mitochondria and downstream apoptosis ultimately via activation of caspase-3. 2. Potential areas where NCCM/BCCM (dotted boxes) may function upstream of activated caspase-9. 3. Potential mechanisms of action of NCCM downstream of activated caspase-9 via may function to inhibit activated caspase-9 and its function within the apoptosome, inhibit XIAP-like activity or by anti-Smac/Diablo activity resulting in inhibition of pro-apoptotic function of Smac/Diablo. 4. NCCM may function or contain XIAP or XIAP-like inhibitors of apoptosis or it may function to inhibit activated caspase-9 and its function within the apoptosome. Abbreviations: NCCM (notochordal cell conditioned medium), BCCM (bovine cell conditioned medium), XIAP (X-linked inhibitor of apoptosis protein), Smac (small mitochondria-derived activator of caspases), Diablo (direct IAP binding protein with low pI).