Dataset Information

Functional Dysregulation of CDC42 Causes Diverse Developmental Phenotypes.

ABSTRACT: Exome sequencing has markedly enhanced the discovery of genes implicated in Mendelian disorders, particularly for individuals in whom a known clinical entity could not be assigned. This has led to the recognition that phenotypic heterogeneity resulting from allelic mutations occurs more commonly than previously appreciated. Here, we report that missense variants in CDC42, a gene encoding a small GTPase functioning as an intracellular signaling node, underlie a clinically heterogeneous group of phenotypes characterized by variable growth dysregulation, facial dysmorphism, and neurodevelopmental, immunological, and hematological anomalies, including a phenotype resembling Noonan syndrome, a developmental disorder caused by dysregulated RAS signaling. In silico, in vitro, and in vivo analyses demonstrate that mutations variably perturb CDC42 function by altering the switch between the active and inactive states of the GTPase and/or affecting CDC42 interaction with effectors, and differentially disturb cellular and developmental processes. These findings reveal the remarkably variable impact that dominantly acting CDC42 mutations have on cell function and development, creating challenges in syndrome definition, and exemplify the importance of functional profiling for syndrome recognition and delineation.

SUBMITTER: Martinelli S

PROVIDER: S-EPMC5985417 | biostudies-literature | 2018 Feb

REPOSITORIES: biostudies-literature

ACCESS DATA

Publications

Functional Dysregulation of CDC42 Causes Diverse Developmental Phenotypes.

Martinelli Simone S Krumbach Oliver H F OHF Pantaleoni Francesca F Coppola Simona S Amin Ehsan E Pannone Luca L Nouri Kazem K Farina Luciapia L Dvorsky Radovan R Lepri Francesca F Buchholzer Marcel M Konopatzki Raphael R Walsh Laurence L Walsh Laurence L Payne Katelyn K Pierpont Mary Ella ME Vergano Samantha Schrier SS Langley Katherine G KG Larsen Douglas D Farwell Kelly D KD Tang Sha S Mroske Cameron C Gallotta Ivan I Di Schiavi Elia E Della Monica Matteo M Lugli Licia L Rossi Cesare C Seri Marco M Cocchi Guido G Henderson Lindsay L Baskin Berivan B Alders Mariëlle M Mendoza-Londono Roberto R Dupuis Lucie L Nickerson Deborah A DA Chong Jessica X JX Meeks Naomi N Brown Kathleen K Causey Tahnee T Cho Megan T MT Demuth Stephanie S Digilio Maria Cristina MC Gelb Bruce D BD Bamshad Michael J MJ Zenker Martin M Ahmadian Mohammad Reza MR Hennekam Raoul C RC Tartaglia Marco M Mirzaa Ghayda M GM

American journal of human genetics 20180125 2

Exome sequencing has markedly enhanced the discovery of genes implicated in Mendelian disorders, particularly for individuals in whom a known clinical entity could not be assigned. This has led to the recognition that phenotypic heterogeneity resulting from allelic mutations occurs more commonly than previously appreciated. Here, we report that missense variants in CDC42, a gene encoding a small GTPase functioning as an intracellular signaling node, underlie a clinically heterogeneous group of p ...[more]

PMID: 29394990

Similar Datasets

Project description:BACKGROUND:TREM2 is a microglial cell surface receptor, with risk mutations linked to Alzheimer's disease (AD), including R47H. TREM2 signalling via SYK aids phagocytosis, chemotaxis, survival, and changes to microglial activation state. In AD mouse models, knockout (KO) of TREM2 impairs microglial clustering around amyloid and prevents microglial activation. The R47H mutation is proposed to reduce TREM2 ligand binding. We investigated cell phenotypes of the R47H mutant and TREM2 KO in a model of human microglia, and compared their transcriptional signatures, to determine the mechanism by which R47H TREM2 disrupts function. METHODS:We generated human microglia-like iPSC-macrophages (pMac) from isogenic induced pluripotent stem cell (iPSC) lines, with homozygous R47H mutation or TREM2 knockout (KO). We firstly validated the effect of the R47H mutant on TREM2 surface and subcellular localization in pMac. To assess microglial phenotypic function, we measured phagocytosis of dead neurons, cell morphology, directed migration, survival, and LPS-induced inflammation. We performed bulk RNA-seq, comparing significant differentially expressed genes (DEGs; p?<?0.05) between the R47H and KO versus WT, and bioinformatically predicted potential upstream regulators of TREM2-mediated gene expression. RESULTS:R47H modified surface expression and shedding of TREM2, but did not impair TREM2-mediated signalling, or gross phenotypes that were dysregulated in the TREM2 KO (phagocytosis, motility, survival). However, altered gene expression in the R47H TREM2 pMac overlapped by 90% with the TREM2 KO and was characterised by dysregulation of genes involved with immunity, proliferation, activation, chemotaxis, and adhesion. Downregulated mediators of ECM adhesion included the vitronectin receptor ?V?3, and consequently, R47H TREM2 pMac adhered weakly to vitronectin compared with WT pMac. To counteract these transcriptional defects, we investigated TGF?1, as a candidate upstream regulator. TGF?1 failed to rescue vitronectin adhesion of pMac, although it improved ?V?3 expression. CONCLUSIONS:The R47H mutation is not sufficient to cause gross phenotypic defects of human pMac under standard culture conditions. However, overlapping transcriptional defects with TREM2 KO supports the hypothesised partial loss-of-function effects of the R47H mutation. Furthermore, transcriptomics can guide us to more subtle phenotypic defects in the R47H cells, such as reduced cell adhesion, and can be used to predict targets for therapeutic intervention.

Project description:TREM2 is a microglial cell surface receptor, with risk mutations linked to Alzheimer’s disease (AD), including R47H. TREM2 signalling via SYK aids phagocytosis, chemotaxis, survival, and changes to microglial activation state. In AD mouse models, knockout (KO) of TREM2 impairs microglial clustering around amyloid, and prevents microglial activation. The R47H mutation is proposed to reduce TREM2 ligand binding. We investigated cell phenotypes of the R47H mutant and TREM2 KO in a model of human microglia, and compared their transcriptional signatures, to determine the mechanism by which R47H TREM2 disrupts function. We generated human microglia-like iPSC-macrophages (pMac) from isogenic induced pluripotent stem cell (iPSC) lines, with homozygous R47H mutation or TREM2 knockout (KO). We firstly validated the effect of the R47H mutant on TREM2 surface and subcellular localization in pMac. To assess microglial phenotypic function we measured phagocytosis of dead neurons, cell morphology, directed migration, survival, and LPS-induced inflammation. We performed bulk RNA-seq, comparing significant differentially-expressed genes (DEGs: p<0.05) between the R47H and KO versus WT, and bioinformatically predicted potential upstream regulators of TREM2-mediated gene expression. Altered gene expression in the R47H TREM2 pMac overlapped by 90% with the TREM2 KO, and was characterized by dysregulation of genes involved with immunity, proliferation, activation, chemotaxis and adhesion. Downregulated mediators of ECM adhesion included the vitronectin receptor αVβ3, and consequently R47H TREM2 pMac adhered weakly to vitronectin compared with WT pMac. To counteract these transcriptional defects, we investigated TGFβ1, as a candidate upstream regulator. TGFβ1 failed to rescue vitronectin adhesion of pMac, although improved αVβ3 expression. The R47H mutation is not sufficient to cause gross phenotypic defects of human pMac under standard culture conditions. However, overlapping transcriptional defects with TREM2 KO supports the hypothesised partial loss-of-function effects of the R47H mutation. Furthermore, transcriptomics can guide us to more subtle phenotypic defects in the R47H cells, such as reduced cell adhesion, and can be used to predict targets for therapeutic intervention.

Dataset Information

Functional Dysregulation of CDC42 Causes Diverse Developmental Phenotypes.

Publications

Functional Dysregulation of CDC42 Causes Diverse Developmental Phenotypes.

Similar Datasets

OmicsDI is part of the ELIXIR infrastructure

Tweets