Active caspase‐3 is required for osteoclast differentiation

Abstract

Based on our earlier observation that caspase-3 is present in osteoclasts that are not undergoing apoptosis, we investigated the role of this protein in the differentiation of primary osteoclasts and RAW264.7 cells (Szymczyk KH, et al., 2005, Caspase-3 activity is necessary for RANKL-induced osteoclast differentiation. The Proceedings of the 8th ICCBMT). We noted that osteoclast numbers are decreased in long bones of procaspase-3 knockout mice and that receptor activator of NF-kappaB ligand (RANKL) does not promote differentiation of isolated preosteoclasts. In addition, after treatment with inhibitors of caspase-3 activity, neither the wild-type primary nor the RAW264.7 cells express TRAP or became multinucleated. We found that immediately following RANKL treatment, procaspase-3 is cleaved and the activated protein is localized to lipid regions of the plasma membrane and the cytosol. We developed RAW264.7 procaspase-3 knockdown clonal cell lines using RNAi technology. Again, treatment with RANKL fails to induce TRAP activity or multinucleation. Finally, we evaluated NF-kappaB in procaspase-3 silenced cells. We found that RANKL treatment prevented activation and nuclear translocation of NF-kappaB. Together these findings provide direct support for the hypothesis that caspase-3 activity is required for osteoclast differentiation.

Sinomenine induces apoptosis in RAW 264.7 cell-derived osteoclasts in vitro via caspase-3 activation

“…Moreover, caspase-3 is the key caspase responsible for the majority of apoptotic effects [24] . A previous study reported that the activation of caspase-3 was required for osteoclast differentiation [25] . However, the excessive activation of caspases in mature osteoclasts induced the proteolytic cascade of apoptosis [26,27] .…”

High d(+)glucose concentration inhibits RANKL-induced osteoclastogenesis

“…Recent studies have shown that caspase-3 is required for RANKL-mediated osteoclast differentiation [29]. RANKL induces cleavage of procaspase-3 to caspase-3 and increases caspase-3 activity that, in turn, activates NF-κB.…”

“…RANKL induces cleavage of procaspase-3 to caspase-3 and increases caspase-3 activity that, in turn, activates NF-κB. Szymczyk et al [29] showed that RAW264.7 procaspase-3 knockdown cells fail to form mature TRACP+ osteoclasts and remain mononuclear. We observed that high D-Glc inhibited caspase-3 activity in response to RANKL in RAW264.7 and BMM cells and this correlated with a predominance of mononuclear cells in cultures and decreased activation of NF-κB.…”

“…RANKL signaling induces caspase-3, an enzyme involved in apoptotic and non-apoptotic events including cell cycle progression, activation and differentiation. Studies in procaspase-3 knockout mice and RAW264.7 cells indicate that osteoclasts fail to differentiate in response to RANKL in the absence of procaspase-3 or when caspase-3 activity is inhibited [29]. Terminal differentiation of osteoclasts is characterized by acquisition of mature phenotypic markers such as the calcitonin receptor (CTR), tartrate resistant acid phosphatase (TRACP) and ability to resorb bone.…”

Potential Therapeutic Efficacy of Curcumin in Liver Cancer

“…Caspase-3, the key member of Caspase family, is a frequently activated death protease, catalyzing the specific cleavage of many key cellular proteins (Szymczyk et al, 2006). Therefore, caspase-3 is essential for certain processes associated with the dismantling of the cell and the formation of apoptotic bodies.…”