Inhibitors of ORAI1 Prevent Cytosolic Calcium-Associated Injury of Human Pancreatic Acinar Cells and Acute Pancreatitis in 3 Mouse Models.

Background & Aims: Sustained activation of the cytosolic calcium concentration induces injury to pancreatic acinar cells and necrosis. The calcium release-activated calcium modulator ORAI1 is the most abundant Ca(2+) entry channel in pancreatic acinar cells; it sustains calcium overload in mice exposed to toxins that induce pancreatitis. We investigated the roles of ORAI1 in pancreatic acinar cell injury and the development of acute pancreatitis in mice.

Modulation of gamma-secretase reduces beta-amyloid deposition in a transgenic mouse model of Alzheimer's disease.

Alzheimer's disease (AD) is characterized pathologically by the abundance of senile plaques and neurofibrillary tangles in the brain. We synthesized over 1200 novel gamma-secretase modulator (GSM) compounds that reduced Abeta(42) levels without inhibiting epsilon-site cleavage of APP and Notch, the generation of the APP and Notch intracellular domains, respectively. These compounds also reduced Abeta(40) levels while concomitantly elevating levels of Abeta(38) and Abeta(37).

Is alpha-T catenin (VR22) an Alzheimer's disease risk gene?

Background: Recently, conflicting reports have been published on the potential role of genetic variants in the alpha-T catenin gene (VR22; CTNNA3) on the risk for Alzheimer's disease. In these papers, evidence for association is mostly observed in multiplex families with Alzheimer's disease, whereas case-control samples of sporadic Alzheimer's disease are predominantly negative.

Methods: After sequencing VR22 in multiplex families with Alzheimer's disease linked to chromosome 10q21, we identified a novel non-synonymous (Ser596Asn; rs4548513) single nucleotide polymorphism (SNP).

High-throughput assessment of mitochondrial membrane potential in situ using fluorescence resonance energy transfer.

Mitochondrial dysfunction causes dozens of debilitating diseases, and is implicated in the etiology of type 2 diabetes, Parkinson's, and Alzheimer's diseases, among others. However, development of mitochondrially targeted therapeutic agents has been impeded by the lack of high-throughput screening techniques that are capable of distinguishing in intact cells the mitochondrial membrane potential (deltapsi(m)) from the plasma membrane potential, (deltapsi(p)). We report here a fluorescence resonance energy transfer (FRET) assay that specifically monitors deltapsi(m) that is not confounded by background signal arising from potentiometric dye responding to deltapsi(p).

STIM1, an essential and conserved component of store-operated Ca2+ channel function.

Store-operated Ca2+ (SOC) channels regulate many cellular processes, but the underlying molecular components are not well defined. Using an RNA interference (RNAi)-based screen to identify genes that alter thapsigargin (TG)-dependent Ca2+ entry, we discovered a required and conserved role of Stim in SOC influx. RNAi-mediated knockdown of Stim in Drosophila S2 cells significantly reduced TG-dependent Ca2+ entry.

Family-based association between Alzheimer's disease and variants in UBQLN1.

Background: Recent analyses suggest that the known Alzheimer's disease genes account for less than half the genetic variance in this disease. The gene encoding ubiquilin 1 (UBQLN1) is one of several candidate genes for Alzheimer's disease located near a well-established linkage peak on chromosome 9q22.

Methods: We evaluated 19 single-nucleotide polymorphisms in three genes within the chromosome 9q linkage region in 437 multiplex families with Alzheimer's disease from the National Institute of Mental Health (NIMH) sample (1439 subjects).

Genetic association of Alzheimer's disease with multiple polymorphisms in alpha-2-macroglobulin.

Alpha-2-Macroglobulin (A2M) is a highly plausible candidate gene for Alzheimer's disease (AD) in a region of chromosome 12 that has numerous independent reports of genetic linkage. We previously reported that a 5 bp deletion in A2M was associated with AD in a subset of the National Institute of Health (NIMH) Genetics Initiative AD family sample. Efforts to replicate this association finding in case - control samples have been largely negative, while those in family samples have been more positive.