Rapid assay for quantitative measurement of apoptosis in cultured cells and brain tissue

Preserved neurogenesis in non-demented individuals with AD neuropathology

Rare individuals remain cognitively intact despite the presence of neuropathology usually associated with fully symptomatic Alzheimer’s disease (AD), which we refer to as Non-Demented with Alzheimer’s disease Neuropathology (NDAN). Understanding the involved mechanism(s) of their cognitive resistance may reveal novel strategies to treat AD-related dementia. In the pursuit of this goal, we determined the number of hippocampal neural stem cells (NSCs) and investigated the expression of several miRNAs in NDAN and AD subjects. Laser-capture microdissection of autopsy human hippocampus DG and qRT-PCR miRNA analyses were combined with immunofluorescence in this study. The number of SOX2⁺ NSCs in the DG was significantly increased in NDAN individuals as compared to AD subjects. Further, the prevalence of SOX2⁺ NSCs was found to correlate with cognitive capacity. Neurogenesis-regulating miRNAs were decreased in NDAN individuals as compared to AD patients. An increased number of NSCs and new neurons in NDAN individuals is associated with a unique expression of regulating miRNAs and strongly support a role of neurogenesis in mediating, in part, the ability of these individuals to resist the pathological burden of AD.

Anandamide-induced Ca2+ elevation leading to p38 MAPK phosphorylation and subsequent cell death via apoptosis in human osteosarcoma cells

The effect of anandamide on human osteoblasts is unclear. This study examined the effect of anandamide on viability, apoptosis, mitogen-activated protein kinases (MAPKs) and Ca2+ levels in MG63 osteosarcoma cells. Anandamide at 50-200 microM decreased cell viability via apoptosis as demonstrated by propidium iodide staining and activation of caspase-3. Immunoblotting suggested that anandamide induced expression of ERK, JNK and p38 MAPK. Anandamide-induced cell death and apoptosis were reversed by SB203580, but not by PD98059 and SP600125, suggesting that anandamide's action was via p38 MAPK, but not via ERK and JNK. Anandamide at 1-100 microM induced [Ca2+]i increases. Removal of extracellular Ca2+ decreased the anandamide response, indicating that anandamide induced Ca2+ influx and Ca2+ release. Chelation of intracellular Ca2+ with BAPTA reversed anandamide-induced cell death and p38 MAPK phosphorylation. Collectively, in MG63 cells, anandamide induced [Ca2+]i increases which evoked p38 MAPK phosphorylation. This p38 MAPK phosphorylation subsequently activated caspase-3 leading to apoptosis.

Bcl-2 localized at the nuclear compartment induces apoptosis after transient overexpression

Bcl-2 is the best characterized member of a large family of proteins that regulate apoptosis. Although it is established that Bcl-2 localized at the mitochondria functions as an anti-apoptotic protein, the function of Bcl-2 at the nucleus remains unclear. Recently we showed that nuclear compartment-associated Bcl-2 inhibits transcription factor activation. Based on this observation, we hypothesized that presence of Bcl-2 at the nucleus may induce rather than protect cells from apoptosis. Here we investigated the putative apoptotic role of nuclear compartment-associated Bcl-2. Additionally, we examined the role of the Bcl-2 BH4 domain in mediating binding to FKBP38, the Bcl-2 mitochondrial chaperone. Our results demonstrate a novel, pro-apoptotic function for nuclear Bcl-2 and identify the Bcl-2 BH4 domain as a key regulator in mediating Bcl-2/FKBP38 binding. These results indicate that Bcl-2 has a dual role as both a protector and a killer and that the ability to switch roles depends on Bcl-2 subcellular localization.