Browsing by Author "Ashley-Koch, AE"

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Open Access
Gene-nutrient interactions that impact magnesium homeostasis increase risk for neural tube defects in mice exposed to dolutegravir.
(Frontiers in cell and developmental biology, 2023-01) Gelineau-van Waes, J; van Waes, MA; Hallgren, J; Hulen, J; Bredehoeft, M; Ashley-Koch, AE; Krupp, D; Gregory, SG; Stessman, HA
In 2018, data from a surveillance study in Botswana evaluating adverse birth outcomes raised concerns that women on antiretroviral therapy (ART) containing dolutegravir (DTG) may be at increased risk for neural tube defects (NTDs). The mechanism of action for DTG involves chelation of Mg²⁺ ions in the active site of the viral integrase. Plasma Mg²⁺ homeostasis is maintained primarily through dietary intake and reabsorption in the kidneys. Inadequate dietary Mg²⁺ intake over several months results in slow depletion of plasma Mg²⁺ and chronic latent hypomagnesemia, a condition prevalent in women of reproductive age worldwide. Mg²⁺ is critical for normal embryonic development and neural tube closure. We hypothesized that DTG therapy might slowly deplete plasma Mg²⁺ and reduce the amount available to the embryo, and that mice with pre-existing hypomagnesemia due to genetic variation and/or dietary Mg²⁺ insufficiency at the time of conception and initiation of DTG treatment would be at increased risk for NTDs. We used two different approaches to test our hypothesis: 1) we selected mouse strains that had inherently different basal plasma Mg²⁺ levels and 2) placed mice on diets with different concentrations of Mg²⁺. Plasma and urine Mg²⁺ were determined prior to timed mating. Pregnant mice were treated daily with vehicle or DTG beginning on the day of conception and embryos examined for NTDs on gestational day 9.5. Plasma DTG was measured for pharmacokinetic analysis. Our results demonstrate that hypomagnesemia prior to conception, due to genetic variation and/or insufficient dietary Mg²⁺ intake, increases the risk for NTDs in mice exposed to DTG. We also analyzed whole-exome sequencing data from inbred mouse strains and identified 9 predicted deleterious missense variants in Fam111a that were unique to the LM/Bc strain. Human FAM111A variants are associated with hypomagnesemia and renal Mg²⁺ wasting. The LM/Bc strain exhibits this same phenotype and was the strain most susceptible to DTG-NTDs. Our results suggest that monitoring plasma Mg²⁺ levels in patients on ART regimens that include DTG, identifying other risk factors that impact Mg²⁺ homeostasis, and correcting deficiencies in this micronutrient might provide an effective strategy for mitigating NTD risk.
Open Access
Largest GWAS of PTSD (N=20 070) yields genetic overlap with schizophrenia and sex differences in heritability.
(Mol Psychiatry, 2017-04-25) Duncan, LE; Ratanatharathorn, A; Aiello, AE; Almli, LM; Amstadter, AB; Ashley-Koch, AE; Baker, DG; Beckham, JC; Bierut, LJ; Bisson, J; Bradley, B; Chen, C-Y; Dalvie, S; Farrer, LA; Galea, S; Garrett, ME; Gelernter, JE; Guffanti, G; Hauser, MA; Johnson, EO; Kessler, RC; Kimbrel, NA; King, A; Koen, N; Kranzler, HR; Logue, MW; Maihofer, AX; Martin, AR; Miller, MW; Morey, RA; Nugent, NR; Rice, JP; Ripke, S; Roberts, AL; Saccone, NL; Smoller, JW; Stein, DJ; Stein, MB; Sumner, JA; Uddin, M; Ursano, RJ; Wildman, DE; Yehuda, R; Zhao, H; Daly, MJ; Liberzon, I; Ressler, KJ; Nievergelt, CM; Koenen, KC
The Psychiatric Genomics Consortium-Posttraumatic Stress Disorder group (PGC-PTSD) combined genome-wide case-control molecular genetic data across 11 multiethnic studies to quantify PTSD heritability, to examine potential shared genetic risk with schizophrenia, bipolar disorder, and major depressive disorder and to identify risk loci for PTSD. Examining 20 730 individuals, we report a molecular genetics-based heritability estimate (h(2)SNP) for European-American females of 29% that is similar to h(2)SNP for schizophrenia and is substantially higher than h(2)SNP in European-American males (estimate not distinguishable from zero). We found strong evidence of overlapping genetic risk between PTSD and schizophrenia along with more modest evidence of overlap with bipolar and major depressive disorder. No single-nucleotide polymorphisms (SNPs) exceeded genome-wide significance in the transethnic (overall) meta-analysis and we do not replicate previously reported associations. Still, SNP-level summary statistics made available here afford the best-available molecular genetic index of PTSD-for both European- and African-American individuals-and can be used in polygenic risk prediction and genetic correlation studies of diverse phenotypes. Publication of summary statistics for ∼10 000 African Americans contributes to the broader goal of increased ancestral diversity in genomic data resources. In sum, the results demonstrate genetic influences on the development of PTSD, identify shared genetic risk between PTSD and other psychiatric disorders and highlight the importance of multiethnic/racial samples. As has been the case with schizophrenia and other complex genetic disorders, larger sample sizes are needed to identify specific risk loci.Molecular Psychiatry advance online publication, 25 April 2017; doi:10.1038/mp.2017.77.