New genetic loci link adipose and insulin biology to body fat distribution.

Body fat distribution is a heritable trait and a well-established predictor of adverse metabolic outcomes, independent of overall adiposity. To increase our understanding of the genetic basis of body fat distribution and its molecular links to cardiometabolic traits, here we conduct genome-wide association meta-analyses of traits related to waist and hip circumferences in up to 224,459 individuals. We identify 49 loci (33 new) associated with waist-to-hip ratio adjusted for body mass index (BMI), and an additional 19 loci newly associated with related waist and hip circumference measures (P < 5 × 10(-8)). In total, 20 of the 49 waist-to-hip ratio adjusted for BMI loci show significant sexual dimorphism, 19 of which display a stronger effect in women. The identified loci were enriched for genes expressed in adipose tissue and for putative regulatory elements in adipocytes. Pathway analyses implicated adipogenesis, angiogenesis, transcriptional regulation and insulin resistance as processes affecting fat distribution, providing insight into potential pathophysiological mechanisms

Patched1 patterns fibroblast growth factor 10 and forkhead box F1 expression during pulmonary branch formation

Hedgehog (Hh) signalling, Fibroblast grovvth factor 10 (Fgr10) and Forkhead box Fl (Foxf1) are each individually important for directing pulmonary branch formation but theft interactions are not well understood. Here we demonstrate that Hh signalling is vital in regulating Foxf1 and Fgf10 expression during branching. The Hedgehog receptor Patched1 (Ptchl) was conditionally inactivated in the lung mesenchyme by Denno1-Cre in vivo or using a recombinant Cie recombinase protein (HNCre) in lung cultures resulting in cell autonomous activation of Hh signalling. Homozygous mesenchymal Ptchl deleted embryos (DertnolCre+/-; Ptch1(lox/lox)) showed secondary branching and lobe formation defects. Fgf 10 expression is spatially reduced in the distal tip of Derrno/Cre+/-; Ptch1(lox/lox) lungs and addition of Fgf10 recombinant protein to these lungs in culture has shown partial restoration of branching, indicating Ptchl function patterns Fgf10 to direct lung branching. Foxil expression is upregulatecl in Dermol Cre+/-; Ptch1(lox/lox) lungs, suggesting Foxf1 may mediate Hh signalling effects in the lung mesenchyme. In vitro HNCre-mecliated Ptchl deleted lung explants support the in vivo observations, with evidence of mesenchyme hyperproliferation and this is consistent with the previously reported role of Hh signalling in maintaining mesenchymal cell survival. Consequently it is concluded that during early pseudoglandular stage of lung development Ptchl patterns Fgf10 and regulates Foxf 1 expression in the lung mesenchyme to direct branch formation and this is essential for proper lobe formation and lung function. (C) 2017 Elsevier B.V. All rights reserved

The spindle-associated microcephaly protein, WDR62, is required for neurogenesis and development of the hippocampus

Primary microcephaly genes (MCPH) are required for the embryonic expansion of the mammalian cerebral cortex. However,\ua0MCPH\ua0mutations may spare growth in other regions of the developing forebrain which reinforces context-dependent functions for distinct\ua0MCPH\ua0genes in neurodevelopment. Mutations in the\ua0MCPH2\ua0gene,\ua0WD40-repeat protein 62\ua0(WDR62), are causative of primary microcephaly and cortical malformations in humans. WDR62 is a spindle microtubule-associated phosphoprotein that is required for timely and oriented cell divisions. Recent studies in rodent models confirm that WDR62 loss or mutation causes thinning of the neocortex and disrupted proliferation of apical progenitors reinforcing critical requirements in the maintenance of radial glia. However, potential contributions for WDR62 in hippocampal development had not been previously defined. Using CRISPR/Cas9 gene editing, we generated mouse models with patient-derived non-synonymous missense mutations (WDR62V66M\ua0and WDR62R439H) and a null mutation (herein referred to as WDR62Stop) for comparison. We find that WDR62 deletion or mutation resulted in a significant reduction in the thickness of the hippocampal ventricular zone and the area of the dentate gyrus (DG). This was associated with the mitotic arrest and depletion of radial glia and intermediate progenitors in the ammonic neuroepithelium. As a consequence, we find that the number of mitotic dentate precursors in the migratory stream and granule neurons in the DG was reduced with WDR62 mutation. These findings reveal that WDR62 is required for neurogenesis and the growth of the hippocampus during embryonic development

The association of microcephaly protein WDR62 with CPAP/IFT88 is required for cilia formation and neocortical development

WDR62 mutations that result in protein loss, truncation or single amino-acid substitutions are causative for human microcephaly, indicating critical roles in cell expansion required for brain development. WDR62 missense mutations that retain protein expression represent partial loss-of-function mutants that may therefore provide specific insights into radial glial cell processes critical for brain growth. Here we utilized CRISPR/Cas9 approaches to generate three strains of WDR62 mutant mice; WDR62V66M/V66M and WDR62R439H/R439H mice recapitulate conserved missense mutations found in humans with microcephaly, with the third strain being a null allele (WDR62stop/stop). Each of these mutations resulted in embryonic lethality to varying degrees and gross morphological defects consistent with ciliopathies (dwarfism, anopthalamia and microcephaly). We find that WDR62 mutant proteins (V66M and R439H) localize to the basal body but fail to recruit CPAP. As a consequence, we observe deficient recruitment of IFT88, a protein that is required for cilia formation. This underpins the maintenance of radial glia as WDR62 mutations caused premature differentiation of radial glia resulting in reduced generation of neurons and cortical thinning. These findings highlight the important role of the primary cilium in neocortical expansion and implicates ciliary dysfunction as underlying the pathology of MCPH2 patients

Centrosome&nbsp;reduction promotes terminal differentiation of human cardiomyocytes

Centrosome reduction and redistribution of pericentriolar material (PCM) coincides with cardiomyocyte transitions to a post-mitotic and matured state. However, it is unclear whether centrosome changes are a cause or consequence of terminal differentiation. We validated that centrosomes were intact and functional in proliferative human pluripotent stem cell-derived cardiomyocytes (hPSC-CMs), consistent with their immature phenotype. We generated acentrosomal hPSC-CMs, through pharmacological inhibition of centriole duplication, and showed that centrosome loss was sufficient to promote post-mitotic transitions and aspects of cardiomyocyte maturation. As Hippo kinases are activated during post-natal cardiac maturation, we pharmacologically activated the Hippo pathway using C19, which was sufficient to trigger centrosome disassembly and relocalization of PCM components to perinuclear membranes. This was due to specific activation of Hippo kinases, as direct inhibition of YAP-TEAD interactions with verteporfin had no effect on centrosome organization. This suggests that Hippo kinase-centrosome remodeling may play a direct role in cardiac maturation.In this article, Ng, Hudson, and colleagues demonstrated that the removal of centrosomes, through blocking centriole duplication, was sufficient to trigger post-mitotic transitions and differentiation of immature human cardiomyocytes. They also revealed that Hippo kinase activation triggered redistribution of centrosomal proteins to acentrosomal sites. This suggests that the regulated disassembly of centrosomes by Hippo kinases may promote cardiomyocyte maturation

Functional genomics identified a novel protein tyrosine phosphatase receptor type f-mediated growth inhibition in hepatocarcinogenesis

It is unclear how proliferating cells elicit suppression on cell proliferation and how cancer cells evade this growth suppression. Using a loss-of-function screening of the human kinome and phosphatome to identify genes suppressing tumor initiation in human hepatocellular carcinoma (HCC), we identified 19 genes and characterized one of the top-scoring tumor suppressor candidates, protein tyrosine phosphatase receptor type F (PTPRF). We found that PTPRF was induced during cell proliferation by cell-cell contact. Ectopic expression of wild-type PTPRF, but not the phosphatase-inactive mutant, suppressed cell proliferation and colony formation in soft-agar assays. In contrast, PTPRF silencing led to cell hyperproliferation, enhanced tumor colony formation in soft agar, and increased xenograft tumor growth in nude mice. Mechanistically, PTPRF silencing showed aberrant ERK-dependent signaling including the phosphorylation/stabilization of v-myc avian myelocytomatosis viral oncogene homolog (MYC) through the direct activation of v-src avian sarcoma viral oncogene homolog (SRC) and suppression of PP2A. This PTPRF-mediated growth suppression during cell proliferation functioned independently of the Hippo-Yap pathway. Clinically, PTPRF was down-regulated in 42% HCC (37/89), 67% gastric cancer (27/40), and 100% colorectal cancer (40/40). PTPRF up-regulation was found in 24% HCC (21/89) and associated with better clinical outcomes. Conclusion: A novel PTPRF-mediated growth suppression pathway was identified by way of a functional genomics screening in human hepatoma cells. Induction of PTPRF by cell-cell contact during cell proliferation quenched the activated ERK-dependent proliferation signaling to prevent cell hyperproliferation and tumor initiation. PTPRF down-regulation in HCC facilitated tumor development. Our findings shed light on how cancer cells can evade growth suppression and open a new avenue for future development of anticancer therapies