Stabilizing ER Ca2+ Channel Function as an Early Preventative Strategy for Alzheimer’s Disease

Alzheimer’s disease (AD) is a devastating neurodegenerative condition with no known cure. While current therapies target late-stage amyloid formation and cholinergic tone, to date, these strategies have proven ineffective at preventing disease progression. The reasons for this may be varied, and could reflect late intervention, or, that earlier pathogenic mechanisms have been overlooked and permitted to accelerate the disease process. One such example would include synaptic pathology, the disease component strongly associated with cognitive impairment. Dysregulated Ca²⁺ homeostasis may be one of the critical factors driving synaptic dysfunction. One of the earliest pathophysiological indicators in mutant presenilin (PS) AD mice is increased intracellular Ca²⁺ signaling, predominantly through the ER-localized inositol triphosphate (IP₃) and ryanodine receptors (RyR). In particular, the RyR-mediated Ca²⁺ upregulation within synaptic compartments is associated with altered synaptic homeostasis and network depression at early (presymptomatic) AD stages. Here, we offer an alternative approach to AD therapeutics by stabilizing early pathogenic mechanisms associated with synaptic abnormalities. We targeted the RyR as a means to prevent disease progression, and sub-chronically treated AD mouse models (4-weeks) with a novel formulation of the RyR inhibitor, dantrolene. Using 2-photon Ca²⁺ imaging and patch clamp recordings, we demonstrate that dantrolene treatment fully normalizes ER Ca²⁺ signaling within somatic and dendritic compartments in early and later-stage AD mice in hippocampal slices. Additionally, the elevated RyR2 levels in AD mice are restored to control levels with dantrolene treatment, as are synaptic transmission and synaptic plasticity. Aβ deposition within the cortex and hippocampus is also reduced in dantrolene-treated AD mice. In this study, we highlight the pivotal role of Ca²⁺ aberrations in AD, and propose a novel strategy to preserve synaptic function, and thereby cognitive function, in early AD patients.     

Rapid Antiretroviral Therapy Initiation for Women in an HIV-1 Prevention Clinical Trial Experiencing Primary HIV-1 Infection during Pregnancy or Breastfeeding

During an HIV-1 prevention clinical trial in East Africa, we observed 16 cases of primary HIV-1 infection in women coincident with pregnancy or breastfeeding. Nine of eleven pregnant women initiated rapid combination antiretroviral therapy (ART), despite having CD4 counts exceeding national criteria for ART initiation; breastfeeding women initiated ART or replacement feeding. Rapid ART initiation during primary HIV-1 infection during pregnancy and breastfeeding is feasible in this setting.     

Development of a real-time TaqMan assay to detect <Emphasis Type="Italic">mendocina</Emphasis> sublineage <Emphasis Type="Italic">Pseudomonas</Emphasis> species in contaminated metalworking fluids

A TaqMan quantitative real-time polymerase chain reaction (qPCR) assay was developed for the detection and enumeration of three Pseudomonas species belonging to the mendocina sublineage (P. oleovorans, P. pseudoalcaligenes, and P. oleovorans subsp. lubricantis) found in contaminated metalworking fluids (MWFs). These microbes are the primary colonizers and serve as indicator organisms of biodegradation of used MWFs. Molecular techniques such as qPCR are preferred for the detection of these microbes since they grow poorly on typical growth media such as R2A agar and Pseudomonas isolation agar (PIA). Traditional culturing techniques not only underestimate the actual distribution of these bacteria but are also time-consuming. The primer–probe pair developed from gyrase B (gyrB) sequences of the targeted bacteria was highly sensitive and specific for the three species. qPCR was performed with both whole cell and genomic DNA to confirm the specificity and sensitivity of the assay. The sensitivity of the assay was 10¹ colony forming units (CFU)/ml for whole cell and 13.7 fg with genomic DNA. The primer–probe pair was successful in determining concentrations from used MWF samples, indicating levels between 2.9 × 10³ and 3.9 × 10⁶ CFU/ml. In contrast, the total count of Pseudomonas sp. recovered on PIA was in the range of <1.0 × 10¹ to 1.4 × 10⁵ CFU/ml for the same samples. Based on these results from the qPCR assay, the designed TaqMan primer–probe pair can be efficiently used for rapid (within 2 h) determination of the distribution of these species of Pseudomonas in contaminated MWFs.     

Modulation of Aβ42 low-n oligomerization using a novel yeast reporter system

Background  

While traditional models of Alzheimer's disease focused on large fibrillar deposits of the Aβ₄₂ amyloid peptide in the brain, recent work suggests that the major pathogenic effects may be attributed to SDS-stable oligomers of Aβ₄₂. These Aβ₄₂ oligomers represent a rational target for therapeutic intervention, yet factors governing their assembly are poorly understood.