Dataset Information

Increased Endothelial Sclerostin Caused by Elevated DSCAM Mediates Multiple Trisomy 21 (Down Syndrome) Phenotypes

ABSTRACT: Trisomy 21 (T21), a recurrent aneuploidy occurring in 1:800 births, predisposes to congenital heart disease (CHD) and multiple extra-cardiac phenotypes. Despite a definitive genetic etiology, the mechanisms by which T21 perturbs development and maintenance remains poorly understood. We compared the transcriptome of CHD tissues from 49 T21 and 226 euploid (eCHD) patients. We resolved cell lineages that mis-expressed T21 transcripts by cardiac single-nucleus RNA-sequencing and RNA in situ hybridization. Compared to eCHD, T21 had increased chr21 gene expression, 11-fold greater levels (p=1.2E-8) of SOST (chr17), encoding the Wnt-inhibitor sclerostin, and 1.4-fold higher levels (p=8.7E-8) of the SOST transcriptional activator ZNF467 (chr7). Cardiac endothelial cells co-expressed SOST and ZNF467. T21 endothelial cells had 6.9-fold higher SOST (p=2.7E-27) with downregulation of Wnt pathway genes. Within the chr21 CHD critical region, the expression of DSCAM was correlated with SOST (p=1.9E-5) and ZNF467 (p=2.9E-4). Deletion of DSCAM in T21 endothelial cells derived from human induced pluripotent stem cells resulted in decreased sclerostin secretion. As Wnt signaling is critical for atrioventricular canal formation, bone health, and pulmonary vascular homeostasis, we conclude that T21-mediated increased sclerostin levels inappropriately inhibits Wnt activities and promotes Down syndrome phenotypes. These findings imply therapeutic potential for anti-sclerostin antibodies in T21.

ORGANISM(S): Homo sapiens

PROVIDER: GSE253244 | GEO | 2024/05/09

REPOSITORIES: GEO

ACCESS DATA

Similar Datasets

Project description:Inhibitors of Wnt signaling have been previously shown to be involved in prostate cancer (PC) metastasis; however the role of Sclerostin (Sost) has not yet been explored. Here we show that elevated Wnt signaling derived from Sost deficient osteoblasts (OBSOSTKO) promotes PC invasion while rhSOST has an inhibitory effect. In contrast, rhDKK1 promotes PC elongation and filopodia formation, morphological changes characteristic of an invasive phenotype. Furthermore, rhDKK1 was found to activate canonical Wnt signaling in PC3 cells as quantified by TOPFLASH reporter and b-catenin activity, suggesting that SOST and DKK1 have opposing roles on Wnt signaling in this context. Gene expression analysis of PC3 cells co-cultured with OBs exhibiting varying amounts of Wnt signaling identified CRIM1 as one of the transcripts up-regulated under highly invasive conditions. Following further analysis we found that CRIM1 increases PC3 invasion, complexes with b-catenin, and promotes cell-adhesion, suggesting that elevated Wnt signaling secreted from the bone may promote PC tropism by promoting CRIM1 expression and facilitating cancer cell invasion and adhesion to bone. We concluded that SOST and DKK1 have opposing effects on PC3 cell invasion and that bone-derived Wnt signaling positively contributes to the invasive phenotypes of metastatic cancer cells by activating CRIM1 expression and facilitating PC-OB physical interaction. As such, we investigated the effects of high concentrations of SOST in vivo. We found that PC3-cells overexpressing SOST injected via tail vein did not readily metastasize in NSG xenografts, suggesting that targeting the molecular bone environment may influence bone metastatic outcome in clinical settings. PC3 cells were cultured for 48 hours in specified conditions prior to RNA extraction and hybridization on Affymetrix Human Genome U133 Plus 2.0 Array. All experiments were performed in at least duplicates. Total RNA was collected from PC3 cells cultured in normal growth media, cocultured with WT mouse osteoblasts supplemented with recombinant human DKK1, cells cocultured with WT mouse osteoblasts supplemented with recombinant human SOST, or cocultured with SostKO mouse osteoblasts.

Project description:WNT signaling is critical in most aspects of skeletal development and homeostasis, and antagonists of WNT signaling are emergning as key regulatory proteins with great promise as therapeutic agents for bone disorders. Until recently Sost and its paralog Sostdc1 have been described as growth factors with highly restricted expression in the adult where Sost was assumed 'osteocyte-' and Sostdc1 'kidney-' specific. Here we show that these two proteins emerged throgh ancestral genome duplication and their expression patterns have diverged to span complimentary domains in most organ systems including musculoskeletal, cardiovascular, nervous, digestive, reproductive and respiratory. In the developing limb, Sost and Sostdc1 display dynamic expression patterns with Sost being restricted to the distal ectoderm and Sostdc1 to the proximal ectoderm and the mesenchyme. While Sostdc1-/- mice lack any obvious limb and skeletal defects, Sost-/- mice recapitulate the hand defects described for sclerosteosis patients. However, elevated WNT signaling in Sost-/-; Sostdc1-/- mice causes misregulation of SHH signaling, ectopic activation of Sox9 in the digit 1 field and ultimately preaxial polydactyly. In addition, we show that the syndactyly documented in Sclerosteosis is present in both Sost-/- and Sost-/-; Sostdc1-/- mice, and is driven by misregulation of Fgf8 in the AER, a region lacking Sost and Sostdc1 expression. This study highlights the complexity of WNT signaling in skeletal biology and disease and emphasizes how redundant mechanisms and non-cell autonomous effects can synergize to unveil new intricate phenotypes caused by elevated WNT signaling. Five arrays were analyzed, consisting of two total embryonic fore-limb RNA (experimental) and three total embryonic forelimb RNA (reference) samples at E11.5 DPC mouse (C57Bl6 strain). Embryos were not pooled to generate samples. Each time point has 3 to 5 biological replicates for limb bud samples, duplicates for whole embryos. Comparisons were made between limb bud samples and whole embryo at the same stage, fore-limb samples of different stages, hind-limb samples of different stages, and fore-limb samples compared to hind-limb samples at the same or the next stage.

Dataset Information

Increased Endothelial Sclerostin Caused by Elevated DSCAM Mediates Multiple Trisomy 21 (Down Syndrome) Phenotypes

Similar Datasets

OmicsDI is part of the ELIXIR infrastructure