👤 Tonnar Castellano

New methods estimate amyloid positivity onset age (EAOA) from amyloid positron emission tomography (PET). We explore the genetics of EAOA to identify molecular factors underlying the earliest Alzheimer's disease (AD) changes. Harmonized amyloid PET data from 4216 participants were used in genome-wide survival, tissue-specific gene expression, and genetic covariance analyses of EAOA. Variants in apolipoprotein E (APOE), ABCA7, and RASGEF1C associated with earlier EAOA. APOE ε4/ε4 and ε3/ε4 converted 6.3 and 5 years earlier than ε3/ε3, respectively. ε2 was protective against earlier EAOA. rs4147929, an expression quantitative trait locus for ABCA7, associated with a 4 year earlier EAOA. This variant was associated with lower brain expression of ABCA7, which was associated with increased amyloid pathology at autopsy. Multiple immune-related diseases shared genetic covariance with EAOA. APOE, ABCA7, and RASGEF1C associated with earlier EAOA, with supporting evidence from tissue-specific expression analyses, offering insights into intervenable targets at early stages of AD. Novel methods estimate how long ago a patient converted to amyloid positivity. Estimating this amyloid clock allows us to determine the onset of the earliest Alzheimer's disease changes. We evaluated what genes influence when someone converts to amyloid positivity. Apolipoprotein E (APOE), ABCA7, and RASGEF1C associated with earlier age of amyloid positivity. Genetic results were supported by tissue-specific expression analyses. Show less

Hepatoblastoma (HB) is a rare embryonal liver tumor, with an increasing global incidence that underscores the need to understand its genetic etiology. Utilizing the ancestry-matched expression quantitative loci data, we performed a HB transcriptome-wide association study (TWAS) on 4,539 Europeans, 1,047 Latinos, and 378 African Americans (∼1:10 case-control ratio). We conducted a meta-analysis of multiancestry transcriptome-wide analysis (METRO), followed by METRO-Egger sensitivity analysis and ancestry-specific gene set enrichment analyses. We further explored genes with additional evidence gathered from independent cohorts and databases. Across the three ancestries, the discovered genes shared the same effect direction across ancestries. A meta-analysis of the three ancestries identified 28 genes significantly associated with HB risk, and 15 were nominally significant for at least two ancestries. Our post-TWAS analyses highlighted 8 genes among these 28, including OXER1 (meta-analysis P value = 7.34 × 10-6), FADS1 (P value = 4.01 × 10-6), and UGDH (P value = 5.29 × 10-8), which were expressed in fetal liver hepatoblast cells and were differentially expressed in tumor and normal tissues in an independent Japanese HB study (P values = 2.61 × 10-13, 3.62 × 10-3, and 1.95 × 10-9, respectively). We pinpointed eight potential genes associated with HB using data from an ongoing multiancestry genome-wide association study. We conducted the largest HB TWAS to date, prompting further exploration of genes. Show less

Aneurysmal subarachnoid hemorrhage (aSAH) is a devastating disease with high morbidity and mortality rates. Within 24 hours after aSAH, monocytes are recruited and enter the subarachnoid space, where they mature into macrophages, increasing the inflammatory response and contributing, along with other factors, to delayed neurological dysfunction and poor outcomes. High-density lipoproteins (HDL) are lipid-protein complexes that exert anti-inflammatory effects but under pathological conditions undergo structural alterations that have been associated with loss of functionality. Plasma HDL were isolated from patients with aSAH and analyzed for their anti-inflammatory activity and protein composition. HDL isolated from patients lost the ability to prevent VCAM-1 expression in endothelial cells (HUVEC) and subsequent adhesion of THP-1 monocytes to the endothelium. Proteomic analysis showed that HDL particles from patients had an altered composition compared to those of healthy subjects. We confirmed by western blot that low levels of apolipoprotein A4 (APOA4) and high of serum amyloid A1 (SAA1) in HDL were associated with the lack of anti-inflammatory function observed in aSAH. Our results indicate that the study of HDL in the pathophysiology of aSAH is needed, and functional HDL supplementation could be considered a novel therapeutic approach to the treatment of the inflammatory response after aSAH. Show less