👤 Christopher R Paradise

To examine cross-sectional and longitudinal associations between vascular risk factors, APOE genotype, and perivascular spaces (PVS), with attention to sex- and region-specific patterns in older adults. Population-based observational study using automated PVS quantification and multivariable regression models. UK Biobank, a large prospective cohort study of community-dwelling adults across the United Kingdom. A total of 38,121 participants (aged 47-90) were included cross-sectionally, and 4,225 longitudinally (mean follow-up 2.61 ± 1.0 years). A deep learning model was applied to brain MRI to quantify PVS in the basal ganglia (BG) and centrum semiovale (CSO). Vascular risk factors included hypertension, hypercholesterolemia, obesity, diabetes, smoking, and alcohol consumption. Models were adjusted for age, sex, scanner, and APOE-ɛ4 carrier status. Cross-sectionally, hypertension (b = 0.089, 95% CI = 0.069-0.108), hypercholesterolemia (b = 0.043, 95% CI = 0.017-0.064), obesity (b = 0.040, 95% CI = 0.016-0.064), and smoking (b = 0.056, 95% CI = 0.037-0.074) were associated with more BG-PVS. APOE-ɛ4 carriers (b = 0.039, 95% CI = 0.0015-0.076) and hypertension (b = 0.093, 95% CI = 0.056-0.130) were linked to more CSO-PVS. Moderate alcohol intake was associated with fewer BG-PVS in males but was associated with higher BG-PVS in females. Longitudinally, risk factor associations with PVS were limited. These findings support the utility of PVS as a biologically meaningful indicator of vascular brain health, with potential relevance for early identification of neurodegenerative risk in older adults. Show less

Epigenetic regulatory proteins support mammalian development, cancer, aging and tissue repair by controlling many cellular processes including stem cell self-renewal, lineage-commitment and senescence in both skeletal and non-skeletal tissues. We review here our knowledge of epigenetic regulatory protein complexes that support the formation of inaccessible heterochromatin and suppress expression of cell and tissue-type specific biomarkers during development. Maintenance and formation of heterochromatin critically depends on epigenetic regulators that recognize histone 3 lysine trimethylation at residues K9 and K27 (respectively, H3K9me3 and H3K27me3), which represent transcriptionally suppressive epigenetic marks. Three chromobox proteins (i.e., CBX1, CBX3 or CBX5) associated with the heterochromatin protein 1 (HP1) complex are methyl readers that interpret H3K9me3 marks which are mediated by H3K9 methyltransferases (i.e., SUV39H1 or SUV39H2). Other chromobox proteins (i.e., CBX2, CBX4, CBX6, CBX7 and CBX8) recognize H3K27me3, which is deposited by Polycomb Repressive Complex 2 (PRC2; a complex containing SUZ12, EED, RBAP46/48 and the methyl transferases EZH1 or EZH2). This second set of CBX proteins resides in PRC1, which has many subunits including other polycomb group factors (PCGF1, PCGF2, PCGF3, PCGF4, PCGF5, PCGF6), human polyhomeotic homologs (HPH1, HPH2, HPH3) and E3-ubiquitin ligases (RING1 or RING2). The latter enzymes catalyze the subsequent mono-ubiquitination of lysine 119 in H2A (H2AK119ub). We discuss biological, cellular and molecular functions of CBX proteins and their physiological and pathological activities in non-skeletal cells and tissues in anticipation of new discoveries on novel roles for CBX proteins in bone formation and skeletal development. Show less