Alterations of Extracellular Calcium Elicit Selective Modes of Cell Death and Protease Activation in SH‐SY5Y Human Neuroblastoma Cells

Abstract

Abstract:The role of intracellular Ca2+ homeostasis in mechanisms of neuronal cell death and cysteine protease activation was investigated in SH-SY5Y human neuroblastoma cells. Cells were incubated in 2 mM EGTA to lower intracellular Ca2+ or 5 mM CaCI, to raise it. Cell death and activation of calpain and caspase-3 were measured. Both EGTA and excess CaCI, elicited cell death. EGTA induced DNA laddering and an increase in caspase-3-like, but not calpain, activity. Pan-caspase inhibitors protected against EGTA-, but not CaCI,-, induced cell death. Conversely, excess Ca2+ elicited necrosis and activated calpain but not caspase-3. Calpain inhibitors did not preserve cell viability. Ca2+ was the death-mediating factor, because restoration of extracelMar Ca2+ protected against cell death induced by EGTA and blockade of Ca2+ channels by Ni'+ protected against that induced by high Ca2+. We conclude that the EGTA treatment lowered intracellular Ca2+ and elicited caspase-3-like protease activity, which led to apoptosis. Conversely, excess extracellular Ca2+ entered Ca2+ channels and increased intracellular Ca2+ leading to calpain activation and necrosis. The mode of cell death and protease activation in response to changing Ca2+ were selective and mutually exclusive, demonstrating that these are useful models to individually investigate apoptosis and necrosis. Key Words: Apoptosis-Necrosis-Calpain-Caspase-3-Ca2+ homeostasis-Neuronal death.

Intratesticular Injection of Calcium Chloride Is a Useful Alternative for Neutering the Male Dog

“…However, there was coagulative necrosis in the seminiferous epithelium and interstitial space as well as presence of degenerated and coagulated germ cells at other place as reported in cat (Jana and Samata, 2011). These histopathological changes were more severe in areas closest to the site of injection; this could be related to necrotizing property of CaCl2 (McGinnis et al, 1999) but less severe morphological changes distal to the site of injection leading to uneven distribution of damage and inconsistent affect on tubules. Under this condition some viable testicular tissue remains or regenerate and may continue secretion of testosterone, although at lower level (NADA, 2003).…”

Endogenous Bax Translocation in SH‐SY5Y Human Neuroblastoma Cells and Cerebellar Granule Neurons Undergoing Apoptosis

“…In light of the recent findings that cleavage of Bcl-2 (Cheng et al, 1997) and Bid (Li et al, 1998;Luo et al, 1998) renders them proapoptotic, it is tempting to speculate that the Bax fragment may serve to augment proapoptotic effects, perhaps by facilitating its insertion or homodimerization within the mitochondrial membrane. However, calpain activation is not necessary for apoptosis: EGTA treatment leads to apoptosis in the absence of calpain activation (McGinnis et al, 1999). Calpain inhibition does not prevent staurosporine-mediated apoptosis in SH-SYSY cells (Nath et al, 1996~).…”

“…EGTA induces apoptosis in SH-SYSY cells via activation of caspase-3-like proteases (McGinnis et al, 1999) and causes apoptosis in other cell types (Chiesa et al, 1998;Mizuno et al, 1998). Treatment with 2 mM EGTA led to increased mitochondrial and decreased cytosolic Bax immunoreactivity (Fig.…”

A novel neuroprotectant PAN-811 protects neurons from oxidative stress

“…Excessive extracellular free calcium ([Ca 2+ ] e ) is able to elicit neuronal cell death [14]. To further confirm the effect of PAN-811 on Ca 2+ , neurons were cotreated with different concentrations of CaCl 2 and 2 μM PAN-811 for 10 days.…”