Reduction of the Cholesterol Sensor SCAP in the Brains of Mice Causes Impaired Synaptic Transmission and Altered Cognitive Function

The sterol sensor SCAP is a key regulator of SREBP-2, the major transcription factor controlling cholesterol synthesis. Recently, we showed that there is a global down-regulation of cholesterol synthetic genes, as well as SREBP-2, in the brains of diabetic mice, leading to a reduction of cholesterol synthesis. We now show that in mouse models of type 1 and type 2 diabetes, this is, in part, the result of a decrease of SCAP. Homozygous disruption of the Scap gene in the brains of mice causes perinatal lethality associated with microcephaly and gliosis. Mice with haploinsufficiency of Scap in the brain show a 60% reduction of SCAP protein and ~30% reduction in brain cholesterol synthesis, similar to what is observed in diabetic mice. This results in impaired synaptic transmission, as measured by decreased paired pulse facilitation and long-term potentiation, and is associated with behavioral and cognitive changes. Thus, reduction of SCAP and the consequent suppression of cholesterol synthesis in the brain may play an important role in the increased rates of cognitive decline and Alzheimer disease observed in diabetic states

Regulation of beta-amyloid production in neurons by astrocyte-derived cholesterol

Alzheimer’s disease (AD) is characterized by the presence of amyloid β (Aβ) plaques, tau tangles, inflammation, and loss of cognitive function. Genetic variation in a cholesterol transport protein, apolipoprotein E (apoE), is the most common genetic risk factor for sporadic AD. In vitro evidence suggests that apoE links to Aβ production through nanoscale lipid compartments (lipid clusters), but its regulation in vivo is unclear. Here, we use superresolution imaging in the mouse brain to show that apoE utilizes astrocyte-derived cholesterol to specifically traffic neuronal amyloid precursor protein (APP) in and out of lipid clusters, where it interacts with β- and γ-secretases to generate Aβ-peptide. We find that the targeted deletion of astrocyte cholesterol synthesis robustly reduces amyloid and tau burden in a mouse model of AD. Treatment with cholesterol-free apoE or knockdown of cholesterol synthesis in astrocytes decreases cholesterol levels in cultured neurons and causes APP to traffic out of lipid clusters, where it interacts with α-secretase and gives rise to soluble APP-α (sAPP-α), a neuronal protective product of APP. Changes in cellular cholesterol have no effect on α-, β-, and γ-secretase trafficking, suggesting that the ratio of Aβ to sAPP-α is regulated by the trafficking of the substrate, not the enzymes. We conclude that cholesterol is kept low in neurons, which inhibits Aβ accumulation and enables the astrocyte regulation of Aβ accumulation by cholesterol signaling

Insulin Action in Brain Regulates Systemic Metabolism and Brain Function

Insulin receptors, as well as IGF-1 receptors and their postreceptor signaling partners, are distributed throughout the brain. Insulin acts on these receptors to modulate peripheral metabolism, including regulation of appetite, reproductive function, body temperature, white fat mass, hepatic glucose output, and response to hypoglycemia. Insulin signaling also modulates neurotransmitter channel activity, brain cholesterol synthesis, and mitochondrial function. Disruption of insulin action in the brain leads to impairment of neuronal function and synaptogenesis. In addition, insulin signaling modulates phosphorylation of tau protein, an early component in the development of Alzheimer disease. Thus, alterations in insulin action in the brain can contribute to metabolic syndrome, and the development of mood disorders and neurodegenerative diseases

Elizabeth Koch, oboe and John Warren, clarinet

Kennnesaw State University School of Music presents Faculty Recital: Elizabeth Koch, oboe and John Warren, clarinet.https://digitalcommons.kennesaw.edu/musicprograms/1546/thumbnail.jp

Age-Related Kidney Transplant Outcomes: Health Disparities Amplified in Adolescence

IMPORTANCE The transition from pediatric to adult health care is a vulnerable time for patients with chronic conditions. We need to better understand the factors affecting the health of kidney transplant recipients during this transition. OBJECTIVE To determine the age at which renal transplant recipients are at greatest risk for graft loss. DESIGN, SETTING, AND PARTICIPANTS We performed a retrospective analysis of 168 809 first kidney-only transplant events from October 1987 through October 2010, in recipients up to age 55 years as reported by the Organ Procurement Transplantation Network Standard Transplant Analysis and Research Database. Recipient age at transplant was the primary predictor studied. Confounder and effect modifier covariates were identified and studied using Cox proportional hazard models. EXPOSURE Kidney-only transplant. MAIN OUTCOMES AND MEASURES Patient and renal graft survival, along with death-censored and non―death-censored information. RESULTS A total of 168 809 renal transplant events met the inclusion criteria. Recipients who received their first kidney transplant at age 14 to 16 years were at the highest risk of graft loss, with inferior outcomes starting at 1 and amplifying at 3, 5, and 10 years after transplant. Black adolescents were at disproportionately high risk of graft failure. The variables that had significant interaction with recipient age were donor type (deceased vs living) and insurance type (government vs private). Among 14-year-old recipients, the risk of death was 175% greater in the deceased donor-government insurance group vs the living donor―private insurance group (hazard ratio, 0.92 [95% CI, 0.90-0.94] vs 0.34 [95% CI, 0.33-0.36]), whereas patient survival rates in the living donor―government insurance and deceased donor―private insurance groups were nearly identical (hazard ratio, 0.61 [95% CI, 0.58-0.63] vs 0.54 [95% CI, 0.51-0.56]). CONCLUSIONS AND RELEVANCE Recipients aged 14 to 16 years have the greatest risk of kidney allograft failure. Black adolescents and those with government insurance are at even higher risk. Private insurance reduces risk of death across all ages. Comprehensive programs are needed for adolescents, especially for those at greater risk, to reduce graft loss during the transition from adolescence to adulthood

Effect of the human papillomavirus (HPV) quadrivalent vaccine in a subgroup of women with cervical and vulvar disease: retrospective pooled analysis of trial data

Objectives To determine the effect of human papillomavirus (HPV) quadrivalent vaccine on the risk of developing subsequent disease after an excisional procedure for cervical intraepithelial neoplasia or diagnosis of genital warts, vulvar intraepithelial neoplasia, or vaginal intraepithelial neoplasia

Chlamydia trachomatis infection and risk of cervical intraepithelial neoplasia

Objectives High-risk human papillomavirus (hrHPV) is the primary cause of cervical cancer. As Chlamydia trachomatis is also linked to cervical cancer, its role as a potential co-factor in the development of cervical intraepithelial neoplasia (CIN) grade 2 or higher was examined. Methods The placebo arms of two large, multinational, clinical trials of an HPV6/11/16/18 vaccine were combined. A total of 8441 healthy women aged 15-26 years underwent cervicovaginal cytology (Papanicolaou (Pap) testing) sampling and C trachomatis testing at day 1 and every 12 months thereafter for up to 4 years. Protocol-specified guidelines were used to triage participants with Pap abnormalities to colposcopy and definitive therapy. The main outcome measured was CIN. Results At baseline, 2629 (31.1%) tested positive for hrHPV DNA and 354 (4.2%) tested positive for C trachomatis. Among those with HPV16/18 infection (n = 965; 11.4%) or without HPV16/18 infection (n = 7382, 87.5%), the hazard ratios (HRs) associated with development of any CIN grade 2 according to baseline C trachomatis status were 1.82 (95% CI: 1.06 to 3.14) and 1.74 (95% CI 1.05 to 2.90), respectively. The results were comparable when only the 12 most common hrHPV infections were considered, but the excess risk disappeared when the outcome was expanded to include CIN grade 3 or worse. Conclusion Further studies based on larger cohorts with longitudinal follow-up in relation to the C trachomatis acquisition and a thorough evaluation of temporal relationships of infections with hrHPV types, C trachomatis and cervical neoplasia are needed to demonstrate whether and how in some situations C trachomatis sets the stage for cervical carcinogenesis. Trial registration NCT00092521 and NCT00092534

Hydrodynamic coupling in microbially mediated fracture mineralization : formation of self-organized groundwater flow channels

Evidence of fossilized microorganisms embedded within mineral veins and mineral-filled fractures has been observed in a wide range of geological environments. Microorganisms can act as sites for mineral nucleation and also contribute to mineral precipitation by inducing local geochemical changes. In this study, we explore fundamental controls on microbially induced mineralization in rock fractures. Specifically, we systematically investigate the influence of hydrodynamics (velocity, flow rate, aperture) on microbially mediated calcite precipitation. Our experimental results demonstrate that a feedback mechanism exists between the gradual reduction in fracture aperture due to precipitation, and its effect on the local fluid velocity. This feedback results in mineral fill distributions that focus flow into a small number of self-organizing channels that remain open, ultimately controlling the final aperture profile that governs flow within the fracture. This hydrodynamic coupling can explain field observations of discrete groundwater flow channeling within fracture-fill mineral geometries where strong evidence of microbial activity is reported

Distinct pattern of TP53 mutations in human immunodeficiency virusâ related head and neck squamous cell carcinoma

Peer Reviewedhttps://deepblue.lib.umich.edu/bitstream/2027.42/142251/1/cncr31063.pdfhttps://deepblue.lib.umich.edu/bitstream/2027.42/142251/2/cncr31063_am.pd