👤 Alex Crowe

African American (AA) adults have a high burden of late-life cognitive impairment (CI) and dementia but remain underrepresented in genetic epidemiology studies. Genetic risk and cardiometabolic diseases (CMDs) contribute to dementia risk. This study investigated whether genetic susceptibility and CMDs were associated with a composite CI outcome and whether CMDs modified these associations. In AA participants within the REasons for Geographic and Racial Differences in Stroke (REGARDS) study, we assessed the association of a dementia polygenic risk score (PRS), APOE ε4 carrier status, and three prevalent CMDs: stroke, coronary artery disease (CAD), and type 2 diabetes (T2D) with a composite outcome of CI and dementia as a contributing cause of death (DCCD). We used logistic regression adjusted for age, sex, education, income, body mass index, smoking status, alcohol intake, physical activity, hypertension, low-density lipoprotein, and C-reactive protein. Interaction terms were included to assess whether CMDs modified the associations between genetic risk and the composite outcome. Of 8,838 participants, 516 (5.84 %) developed CI or had DCCD. In fully adjusted models, high polygenic risk (highest vs lowest PRS tertile) was associated with increased odds of the composite outcome [odds ratio (OR): 1.42; 95 % confidence interval (CI): 1.12-1.78], as was APOE ε4 carrier status (OR: 1.46; 95% CI: 1.21-1.78). Among CMDs, stroke (OR: 1.45; 95% CI: 1.04-2.02) and T2D (OR: 1.31; 95% CI: 1.06-1.61) were significantly associated with increased odds of the composite outcome. However, the association between genetic risk and the composite outcome did not significantly differ by CMD status. Genetic risk and CMDs independently contributed to dementia-related outcomes, indicating their relevance in understanding dementia risk among AA adults. Show less

Alzheimer's disease (AD) is characterized by the presence of tau protein inclusions and amyloid beta (Aβ) plaques in the brain, with Aβ peptides generated by cleavage of the amyloid precursor protein (APP) by BACE1 and γ-secretase. We previously described a primary rat neuron assay in which tau inclusions form from endogenous rat tau after seeding cells with insoluble tau isolated from the human AD brain. Here, we used this assay to screen an annotated library of ∼8700 biologically active small molecules for their ability to reduce immuno-stained neuronal tau inclusions. Compounds causing ≥30% inhibition of tau aggregates with <25% loss of DAPI-positive cell nuclei underwent further confirmation testing and assessment of neurotoxicity, and non-neurotoxic hits were subsequently analyzed for inhibitory activity in an orthogonal ELISA that quantified multimeric rat tau species. Of the 173 compounds meeting all criteria, a subset of 55 inhibitors underwent concentration-response testing and 46 elicited a concentration-dependent reduction of neuronal tau inclusions that were distinct from measures of toxicity. Among the confirmed inhibitors of tau pathology were BACE1 inhibitors, several of which, along with γ-secretase inhibitors/modulators, caused a concentration-dependent lowering of neuronal tau inclusions and a reduction of insoluble tau by immunoblotting, although they did not decrease soluble phosphorylated tau species. In conclusion, we have identified a diverse set of small molecules and related targets that reduce neuronal tau inclusions. Notably, these include BACE1 and γ-secretase inhibitors, suggesting that a cleavage product from a shared substrate, such as APP, might affect tau pathology. Show less

There is an incomplete understanding of the burden of splice-disrupting variants in definitively associated inherited heart disease genes and whether these genes can amplify from blood RNA to support functional confirmation of splicing outcomes. We performed burden testing of rare splice-disrupting variants in people with inherited heart disease and sudden unexplained death compared to 125,748 population controls. ClinGen definitively disease-associated inherited heart disease genes were amplified using RNA extracted from fresh blood, derived cardiomyocytes, and myectomy tissue. Variants were functionally assessed and classified for pathogenicity. We found 88 in silico-predicted splice-disrupting variants in 128 out of 1242 (10.3%) unrelated participants. There was an excess burden of splice-disrupting variants in PKP2 (5.9%), FLNC (2.7%), TTN (2.8%), MYBPC3 (8.2%) and MYH7 (1.3%), in distinct cardiomyopathy subtypes, and KCNQ1 (3.6%) in long QT syndrome. Blood RNA supported the amplification of 21 out of 31 definitive disease-associated inherited heart disease genes. Our functional studies confirmed altered splicing in six variants. Eleven variants of uncertain significance were reclassified as likely pathogenic based on functional studies and six were used for cascade genetic testing in 12 family members. Our study highlights that splice-disrupting variants are a significant cause of inherited heart disease, and that analysis of blood RNA confirms splicing outcomes and supports variant pathogenicity classification. Show less

Current bovine pregnancy detection methods are not reliable until at least day 28 post artificial insemination (AI). The bovine estrous cycle is approximately 21 days; consequently, producers miss an opportunity to rebreed at the next estrous event. Therefore, commercial interest exists for the discovery of novel biomarkers of pregnancy which could reliably detect pregnancy status at or before day 21 of pregnancy. The objective of the present study was to use liquid chromatography tandem mass spectrometry (LC-MS/MS) to perform a global, label-free, proteomics study on (i) milk whey and (ii) extracellular vesicle (EV) enriched milk whey samples, from day 21 of pregnancy, compared with day 21 of the estrous cycle, in order to identify potential protein biomarkers of early pregnancy. The estrous cycles of 10 dairy cows were synchronized, they went through one (control) estrous cycle and these cows were artificially inseminated during the following estrus. These cows were confirmed pregnant by ultrasound scanning. Milk whey samples were collected on day 21 of the estrous cycle and on day 21 post AI. Milk whey samples and EV enriched milk whey samples were analyzed by LC-MS/MS and subsequent analyzes of the label-free quantitative data was performed in MaxQuant and Perseus. Four proteins (APOB, SPADH1, PLIN2 and LPO) were differentially expressed between the proteomes of milk whey from day 21 of pregnancy and day 21 of the estrous cycle (P < 0.05). Ten proteins (PIGR, PGD, QSOX1, MUC1, SRPRA, MD2, GAPDH, FOLR1, GPRC5B and HHIPL2) were differentially expressed between the proteomes of EV enriched milk whey from day 21 of pregnancy and day 21 of the estrous cycle (P < 0.05). These proteins are potential milk whey biomarkers of early pregnancy. Show less