Browsing by Author "Duque, Gustavo"

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    Bivariate genome-wide association meta-analysis of pediatric musculoskeletal traits reveals pleiotropic effects at the SREBF1/TOM1L2 locus
    (Nature Publishing Group, 2017-07-25) Medina-Gomez, Carolina; Kemp, John P.; Dimou, Niki L.; Kreiner, Eskil; Chesi, Alessandra; Zemel, Babette S.; Bønnelykke, Klaus; Boer, Cindy G.; Ahluwalia, Tarunveer S.; Bisgaard, Hans; Evangelou, Evangelos; Heppe, Denise H.M.; Bonewald, Lynda F.; Gorski, Jeffrey P.; Ghanbari, Mohsen; Demissie, Serkalem; Duque, Gustavo; Maurano, Matthew T.; Kiel, Douglas P.; Hsu, Yi-Hsiang; Eerden, Bram C.J. van der; Ackert-Bicknell, Cheryl; Reppe, Sjur; Gautvik, Kaare M.; Raastad, Truls; Karasik, David; Peppel, Jeroen van de; Jaddoe, Vincent W.V.; Uitterlinden, André G.; Tobias, Jonathan H.; Grant, Struan F.A.; Bagos, Pantelis G.; Evans, David M.; Rivadeneira, Fernando; Anatomy and Cell Biology, School of Medicine
    Bone mineral density is known to be a heritable, polygenic trait whereas genetic variants contributing to lean mass variation remain largely unknown. We estimated the shared SNP heritability and performed a bivariate GWAS meta-analysis of total-body lean mass (TB-LM) and total-body less head bone mineral density (TBLH-BMD) regions in 10,414 children. The estimated SNP heritability is 43% (95% CI: 34-52%) for TBLH-BMD, and 39% (95% CI: 30-48%) for TB-LM, with a shared genetic component of 43% (95% CI: 29-56%). We identify variants with pleiotropic effects in eight loci, including seven established bone mineral density loci: WNT4, GALNT3, MEPE, CPED1/WNT16, TNFSF11, RIN3, and PPP6R3/LRP5. Variants in the TOM1L2/SREBF1 locus exert opposing effects TB-LM and TBLH-BMD, and have a stronger association with the former trait. We show that SREBF1 is expressed in murine and human osteoblasts, as well as in human muscle tissue. This is the first bivariate GWAS meta-analysis to demonstrate genetic factors with pleiotropic effects on bone mineral density and lean mass.Bone mineral density and lean skeletal mass are heritable traits. Here, Medina-Gomez and colleagues perform bivariate GWAS analyses of total body lean mass and bone mass density in children, and show genetic loci with pleiotropic effects on both traits.
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    Mechanisms of Palmitate-Induced Lipotoxicity in Osteocytes
    (Elsevier, 2019-10) Al Saedi, Ahmed; Bermeo, Sandra; Plotkin, Lilian; Myers, Damian E.; Duque, Gustavo; Anatomy and Cell Biology, IU School of Medicine
    Background Lipotoxicity is defined as cellular toxicity observed in the presence of an abnormal accumulation of fat and adipocyte-derived factors in non-fat tissues. Palmitic acid (PA), an abundant fatty acid in the bone marrow and particularly in osteoporotic bones, affects osteoblastogenesis and osteoblast function, decreasing their survival through induction of apoptosis and dysfunctional autophagy. In this study, we hypothesized that PA also has a lipotoxic effect on osteocytes in vitro. Methods Initially, we tested the effect of PA on osteocyte-derived factors DKK1, sclerostin and RANKL. Then, we tested whether PA affects survival and causes apoptosis in osteocytes. Subsequently, we investigated the effect of PA on autophagy by detecting the membrane component LC3-II (Western blot) and staining it and lysosomes with Lysotracker Red dye. Results PA decreases RANKL, DKK1 and sclerostin expression in osteocytes. In addition, we found that PA induces apoptosis and reduces osteocyte survival. PA also caused autophagy failure identified by a significant increase in LC3-II and a reduced number of autophagosomes/lysosomes in the cytoplasm. Conclusion In addition to the effects of PA on RANKL, DKK1 and sclerostin expression, which could have significant deleterious impact on bone cell coupling and bone turnover, PA also induced apoptosis and reduced autophagy in osteocytes. Considering that apoptosis and cell dysfunction are two common changes occurring in the osteocytes of osteoporotic bone, our findings suggest that PA could play a role in the pathogenesis of the disease. Suppression of these effects could bring new potential targets for therapeutic interventions in the future.