👤 Ryan L Earley

Red blood cell (RBC) metabolism regulates hemolysis during aging in vivo and in the blood bank. Here, we leveraged a diversity outbred mouse population to map the genetic drivers of fresh/stored RBC metabolism and extravascular hemolysis upon storage and transfusion in 350 mice. We identify the ferrireductase Steap3 as a critical regulator of a ferroptosis-like process of lipid peroxidation. Steap3 polymorphisms were associated with RBC iron content, in vitro hemolysis, and in vivo extravascular hemolysis both in mice and 13,091 blood donors from the Recipient Epidemiology and Donor evaluation Study. Using metabolite Quantitative Trait Loci analyses, we identified a network of gene products (FADS1/2, EPHX2 and LPCAT3) - enriched in donors of African descent - associated with oxylipin metabolism in stored human RBCs and related to Steap3 or its transcriptional regulator, the tumor protein TP53. Genetic variants were associated with lower in vivo hemolysis in thousands of single-unit transfusion recipients. Steap3 regulates lipid peroxidation and extravascular hemolysis in 350 diversity outbred miceSteap3 SNPs are linked to RBC iron, hemolysis, vesiculation in 13,091 blood donorsmQTL analyses of oxylipins identified ferroptosis-related gene products FADS1/2, EPHX2, LPCAT3Ferroptosis markers are linked to hemoglobin increments in transfusion recipients. Show less

Ischaemic stroke is a common complication of sickle cell disease (SCD) and without intervention can affect 11% of children with SCD before the age of 20. Within the Trans-Omics for Precision Medicine (TOPMed), a genome-wide association study (GWAS) of ischaemic stroke was performed on 1333 individuals with SCD from Brazil (178 cases, 1155 controls). Via a novel Cox proportional-hazards analysis, we searched for variants associated with ischaemic stroke occurring at younger ages. Variants at genome-wide significance (p < 5 × 10 Show less

Histone modifications such as methylation of key lysine residues play an important role in embryonic development in a variety of organisms such as of Pacific oysters, zebrafish and mice. The action of demethylase ("erasers") and methyltransferase ("writers") enzymes regulates precisely the methylation status of each lysine residue. However, despite fishes being very useful model organisms in medicine, evolution and ecotoxicology, most studies have focused on mammalian and plant model organisms, and mechanisms underlying regulation of histones are unknown in fish development outside of zebrafish. Here, putative histone lysine demethylases (Kdm) and methyltransferases (Kmt) were identified in an isogenic lineage of the self-fertilizing hermaphroditic vertebrate, the mangrove rivulus fish, Kryptolebias marmoratus. Evolutionary relationships with other animal demethylases and methyltransferases were examined, and expression patterns during embryonic development and in adult tissues were characterized. Twenty-five Kdm orthologues (Jarid2, Jmjd1c, Jmjd4, Jmjd6, Jmjd7, Jmjd8, Kdm1a, Kdm1b, Kdm2a, Kdm2b, Kdm3b, Kdm4a, Kdm4b, Kdm4c, Kdm5a, Kdm5b, Kdm5c, Kdm6a, Kdm6b, Kdm7a, Kdm8, Kdm9, UTY, Phf2 and Phf8) and forty-eight Kmt orthologues (Ezh1, Ezh2, Setd2, Nsd1, Nsd2, Nsd3, Ash1l, Kmt2e, Setd5, Prdm1, Prdm2, Prdm4, Prdm5, Prdm6, Prdm8, Prdm9, Prdm10, Prdm11, Prdm12, Prdm13, Prdm14, Prdm15, Prdm16, Setd3, Setd4, Setd6, Setd1a, Setd1b, Kmt2a, Kmt2b, Kmt2c, Kmt2d, Kmt5a, Kmt5b, Ehmt1, Ehmt2, Suv39h1, Setmar, Setdb1, Setdb2, Smyd1, Smyd2, Smyd3, Smyd4, Smyd5, Setd7, Setd9, Dot1l) were discovered. Expression patterns of both Kdm and Kmt were variable during embryonic development with a peak in gastrula stage and a reduction in later embryogenesis. Expression of both Kdm and Kmt was higher in male brains compared to hermaphrodite brains whereas specific expression patterns of Kdm and Kmt were observed in the hermaphrodite ovotestes and male testes, respectively. Putative histone demethylases (Kdm) and methyltransferases (Kmt) were for the first time characterized in a teleost besides zebrafish, the mangrove rivulus. Their domain conservation and expression profiles suggest that they might play important roles during development, gametogenesis and neurogenesis, which raises questions about epigenetic regulation of these processes by histone lysine methylation in K. marmoratus. Due to its peculiar mode of reproduction and the natural occurrence of isogenic lineages, this new model species is of great interest for understanding epigenetic contributions to the regulation of development and reproduction. Show less

Restless Legs syndrome (RLS) is a common sleep disorder for which the genetic contribution remains poorly explained. In 2007, the first large scale genome wide association study (GWAS) identified three genomic regions associated with RLS. MEIS1, BTBD9 and MAP2K5/SKOR1 are the only known genes located within these loci and their association with RLS was subsequently confirmed in a number of follow up GWAS. Following this finding, our group reported the MEIS1 risk haplotype to be associated with its decreased expression at the mRNA and protein levels. Here we report the effect of the risk variants of the three other genes strongly associated with RLS. While these variants had no effect on the mRNA levels of the genes harboring them, we find that the homeobox transcription factor MEIS1 positively regulates the expression of the transcription co-repressor SKOR1. This regulation appears mediated through the binding of MEIS1 at two specific sites located in the SKOR1 promoter region and is modified by an RLS associated SNP in the promoter region of the gene. Our findings directly link MEIS1 and SKOR1, two significantly associated genes with RLS and also prioritize SKOR1 over MAP2K5 in the RLS associated intergenic region of MAP2K5/SKOR1 found by GWAS. Show less

Restless legs syndrome (RLS) is a common disorder, with several known genetic risk factors, yet the actual genetic causes are unclear. Whole-exome sequencing (WES) was performed in seven RLS families, focusing on six known genetic loci: MEIS1, BTBD9, PTPRD, MAP2K5/SKOR1, TOX3, and rs6747972. Genotyping using specific TaqMan assays was performed in two case-control cohorts (627 patients and 410 controls), and in a familial cohort (n = 718). WES identified two candidate GLO1 variants (within the BTBD9 locus), p.E111A and the promoter variant c.-7C>T, both co-segregated with the disease in four families. The GLO1 p.E111A variant was associated with RLS in the French-Canadian cohort (odds ratio, OR = 1.38, p = 0.02), and demonstrated a similar trend in the US cohort (OR = 1.26, p = 0.09, combined analysis OR = 1.28, p = 0.009). However, the original genome-wide association study (GWAS) marker, BTBD9 rs9357271, had stronger association with RLS (OR = 1.84, p = 0.0003). Conditional haplotype analysis, controlling for the effect of the BTBD9 variant rs9357271, demonstrated that the association of GLO1 p.E111A turned insignificant (p = 0.54). In the familial cohort, the two GLO1 variants were not associated with RLS. Other variants in the SKOR1 (p.W200R and p.A672V) and PTPRD (p.R995C, p.Q447E, p.T781A, p.Q447E, and c.551-4C > G) genes, did not co-segregate with the disease. The GLO1 variations studied here are not the source of association of the BTBD9 locus with RLS. It is likely that the genetic variants affecting RLS susceptibility are located in regulatory regions. Show less