ORCID Profile
0000-0001-6539-3069
Current Organisations
The University of Edinburgh
,
NHS Lothian
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Publisher: Public Library of Science (PLoS)
Date: 11-12-2009
Publisher: American Association for the Advancement of Science (AAAS)
Date: 30-03-2016
DOI: 10.1126/SCITRANSLMED.AAD9982
Abstract: Mutant Pik3ca gives rise to venous malformations.
Publisher: Springer Science and Business Media LLC
Date: 26-06-2011
DOI: 10.1038/NG.866
Publisher: Hindawi Limited
Date: 06-2017
DOI: 10.1002/HUMU.23233
Publisher: American Society for Clinical Investigation
Date: 12-2010
DOI: 10.1172/JCI43653
Publisher: Elsevier BV
Date: 10-2006
Publisher: Springer Science and Business Media LLC
Date: 29-06-2017
DOI: 10.1038/S41598-017-03054-8
Abstract: Obesity is a genetically heterogeneous disorder. Using targeted and whole-exome sequencing, we studied 32 human and 87 rodent obesity genes in 2,548 severely obese children and 1,117 controls. We identified 52 variants contributing to obesity in 2% of cases including multiple novel variants in GNAS , which were sometimes found with accelerated growth rather than short stature as described previously. Nominally significant associations were found for rare functional variants in BBS1 , BBS9 , GNAS , MKKS , CLOCK and ANGPTL6 . The p.S284X variant in ANGPTL6 drives the association signal (rs201622589, MAF~0.1%, odds ratio = 10.13, p-value = 0.042) and results in complete loss of secretion in cells. Further analysis including additional case-control studies and population controls (N = 260,642) did not support association of this variant with obesity (odds ratio = 2.34, p-value = 2.59 × 10 −3 ), highlighting the challenges of testing rare variant associations and the need for very large s le sizes. Further validation in cohorts with severe obesity and engineering the variants in model organisms will be needed to explore whether human variants in ANGPTL6 and other genes that lead to obesity when deleted in mice, do contribute to obesity. Such studies may yield druggable targets for weight loss therapies.
Publisher: Oxford University Press (OUP)
Date: 07-2015
DOI: 10.1093/JNCI/DJV178
Publisher: Oxford University Press (OUP)
Date: 24-12-2018
DOI: 10.1093/NAR/GKY1295
Publisher: American Society for Clinical Investigation
Date: 09-2010
DOI: 10.1172/JCI43122
Publisher: Springer Science and Business Media LLC
Date: 05-06-2015
DOI: 10.1038/NCOMMS8074
Abstract: The analysis of in iduals with ciliary chondrodysplasias can shed light on sensitive mechanisms controlling ciliogenesis and cell signalling that are essential to embryonic development and survival. Here we identify TCTEX1D2 mutations causing Jeune asphyxiating thoracic dystrophy with partially penetrant inheritance. Loss of TCTEX1D2 impairs retrograde intraflagellar transport (IFT) in humans and the protist Chlamydomonas , accompanied by destabilization of the retrograde IFT dynein motor. We thus define TCTEX1D2 as an integral component of the evolutionarily conserved retrograde IFT machinery. In complex with several IFT dynein light chains, it is required for correct vertebrate skeletal formation but may be functionally redundant under certain conditions.
Publisher: Cold Spring Harbor Laboratory
Date: 04-11-2022
DOI: 10.1101/2022.11.04.515167
Abstract: A biallelic missense mutation in mitofusin 2 ( MFN2 ) causes multiple symmetric lipomatosis and partial lipodystrophy, implicating disruption of mitochondrial fusion or interaction with other organelles in adipocyte differentiation, growth and/or survival. In this study, we aimed to document the impact of loss of mitofusin 1 ( Mfn1 ) or 2 ( Mfn2) on adipogenesis in cultured cells. We characterised adipocyte differentiation of wildtype (WT), Mfn1 -/- and Mfn2 -/- mouse embryonic fibroblasts (MEFs) and 3T3-L1 preadipocytes in which Mfn1 or 2 levels were reduced using siRNA. Mfn1 -/- MEFs displayed striking fragmentation of the mitochondrial network, with surprisingly enhanced propensity to differentiate into adipocytes, as assessed by lipid accumulation, expression of adipocyte markers ( Plin1, Fabp4, Glut4, Adipoq ), and insulin-stimulated glucose uptake. RNA sequencing revealed a corresponding pro-adipogenic transcriptional profile including Pparg upregulation. Mfn2 -/- MEFs also had a disrupted mitochondrial morphology, but in contrast to Mfn1 −/- MEFs they showed reduced expression of adipocyte markers and no increase in insulin-stimulated glucose uptake. Mfn1 and Mfn2 siRNA mediated knockdown studies in 3T3-L1 adipocytes generally replicated these findings. Loss of Mfn1 but not Mfn2 in cultured pre-adipocyte models is pro-adipogenic. This suggests distinct, non-redundant roles for the two mitofusin orthologues in adipocyte differentiation.
Publisher: Elsevier BV
Date: 07-2013
Publisher: Springer Science and Business Media LLC
Date: 06-03-2015
DOI: 10.1038/NCOMMS6681
Abstract: Normal thyroid function is essential for health, but its genetic architecture remains poorly understood. Here, for the heritable thyroid traits thyrotropin (TSH) and free thyroxine (FT4), we analyse whole-genome sequence data from the UK10K project ( N =2,287). Using additional whole-genome sequence and deeply imputed data sets, we report meta-analysis results for common variants (MAF≥1%) associated with TSH and FT4 ( N =16,335). For TSH, we identify a novel variant in SYN2 (MAF=23.5%, P =6.15 × 10 −9 ) and a new independent variant in PDE8B (MAF=10.4%, P =5.94 × 10 −14 ). For FT4, we report a low-frequency variant near B4GALT6/SLC25A52 (MAF=3.2%, P =1.27 × 10 −9 ) tagging a rare TTR variant (MAF=0.4%, P =2.14 × 10 −11 ). All common variants explain ≥20% of the variance in TSH and FT4. Analysis of rare variants (MAF %) using sequence kernel association testing reveals a novel association with FT4 in NRG1. Our results demonstrate that increased coverage in whole-genome sequence association studies identifies novel variants associated with thyroid function.
Publisher: Hindawi Limited
Date: 30-09-2015
DOI: 10.1002/HUMU.22901
Publisher: EMBO
Date: 19-05-2023
Publisher: Cold Spring Harbor Laboratory
Date: 24-11-2017
DOI: 10.1101/224485
Abstract: Heterodimeric class IA phosphatidylinositol-3-kinases (PI3K) transduce signals from many receptor tyrosine kinases including the insulin receptor. PI3K recruitment to phosphotyrosines is mediated by Pik3r1 gene products including the most intensely studied PI3K regulatory subunit, p85α, which also binds and regulates the PIP3 phosphatase Pten, and the lipogenic transcription factor Xbp1. Mutations in human PIK3R1 cause SHORT syndrome, featuring lipodystrophy and severe insulin resistance which, uniquely, are uncoupled from fatty liver and dyslipidemia. We describe a novel mouse model of SHORT syndrome made by knock in of the Pik3r1 Y657X mutation. Homozygous embryos die at E11.5, while heterozygous mice exhibit pre-and postnatal growth impairment with diminished placental vascularity. Adipose tissue accretion on high fat feeding was reduced, however adipocyte size was unchanged and preadipocyte differentiation ex vivo unimpaired. Despite severe insulin resistance, heterozygous mice were hypolipidemic, and plasma adiponectin, liver weight, cholesterol, glycogen and triglyceride content were unchanged. Mild downregulation of lipogenic Srebp1, Srebp2 and Chrebp transcriptional activity but no suppression of Xbp1 target genes was seen after fasting. These findings give new insights into the developmental role of Pik3r1, and establish a model of lipodystrophic insulin resistance dissociated from dyslipidemia as seen in SHORT syndrome.
Publisher: Elsevier BV
Date: 12-2018
Publisher: Elsevier BV
Date: 05-2019
Publisher: Springer Science and Business Media LLC
Date: 14-09-2015
DOI: 10.1038/NATURE14962
Publisher: Springer Science and Business Media LLC
Date: 24-11-2017
DOI: 10.1038/S41467-017-02002-4
Abstract: Mutations in PIK3CA are very frequent in cancer and lead to sustained PI3K pathway activation. The impact of acute expression of mutant PIK3CA during early stages of malignancy is unknown. Using a mouse model to activate the Pik3ca H1047R hotspot mutation in the heterozygous state from its endogenous locus, we here report that mutant Pik3ca induces centrosome lification in cultured cells (through a pathway involving AKT, ROCK and CDK2/Cyclin E-nucleophosmin) and in mouse tissues, and increased in vitro cellular tolerance to spontaneous genome doubling. We also present evidence that the majority of PIK3CA H1047R mutations in the TCGA breast cancer cohort precede genome doubling. These previously unappreciated roles of PIK3CA mutation show that PI3K signalling can contribute to the generation of irreversible genomic changes in cancer. While this can limit the impact of PI3K-targeted therapies, these findings also open the opportunity for therapeutic approaches aimed at limiting tumour heterogeneity and evolution.
Publisher: Springer Science and Business Media LLC
Date: 21-01-2019
DOI: 10.1038/S41467-018-07863-X
Abstract: Cranial growth and development is a complex process which affects the closely related traits of head circumference (HC) and intracranial volume (ICV). The underlying genetic influences shaping these traits during the transition from childhood to adulthood are little understood, but might include both age-specific genetic factors and low-frequency genetic variation. Here, we model the developmental genetic architecture of HC, showing this is genetically stable and correlated with genetic determinants of ICV. Investigating up to 46,000 children and adults of European descent, we identify association with final HC and/or final ICV + HC at 9 novel common and low-frequency loci, illustrating that genetic variation from a wide allele frequency spectrum contributes to cranial growth. The largest effects are reported for low-frequency variants within TP53 , with 0.5 cm wider heads in increaser-allele carriers versus non-carriers during mid-childhood, suggesting a previously unrecognized role of TP53 transcripts in human cranial development.
Publisher: Springer Science and Business Media LLC
Date: 11-02-2015
DOI: 10.1038/NATURE14132
Location: United Kingdom of Great Britain and Northern Ireland
Location: United Kingdom of Great Britain and Northern Ireland
Location: United Kingdom of Great Britain and Northern Ireland
Location: United Kingdom of Great Britain and Northern Ireland
No related grants have been discovered for Robert Kenneth Semple.