Transcriptional changes in GNAQ R183Q mouse back skin
Ontology highlight
ABSTRACT: We used RNA-Seq to search for potential downstream effectors of GNAQ R183Q during the developent of vascular phenotypes in the mouse back skin.
Project description:Sturge-Weber syndrome (SWS) is a sporadic, congenital, neuro-cutaneous disorder characterized by a mosaic, capillary malformation. SWS and isolated capillary malformations are caused by a somatic activating mutation in GNAQ encoding the G protein subunit alpha-q protein. The missense mutation R183Q is the sole GNAQ mutation identified thus far in affected tissues of 90% of SWS patients. In this study, we sequenced skin biopsies of affected capillary malformations from 9 patients. We identified the R183Q mutation in nearly all samples, but one sample exhibited a Q209R mutation. This new mutation occurs at the same residue as the constitutively-activating Q209L mutation, commonly seen in tumors. However, Q209R is a rare variant in this gene. To compare the effect of the Q209R mutation on downstream signaling, we performed reporter assays with a GNAQ-responsive reporter co-transfected with either GNAQ WT, R183Q, Q209L, Q209R, or C9X (representing a null allele). Q209L showed the highest reporter activation, with R183Q and Q209R showing significantly lower activation. To determine whether these mutations had similar or different downstream consequences we performed RNAseq analysis in microvascular endothelial cells (HMEC-1) electroporated with the same GNAQ variants. The R183 and Q209 missense variants caused extensive dysregulation of a broad range of transcripts compared to the WT or null allele, confirming that these are all activating mutations. However, the missense variants exhibited very few differentially expressed genes (DEGs) when compared to each other. These data suggest that these activating GNAQ mutations differ in magnitude of activation but have similar downstream effects.
Project description:Introduction: Capillary malformation (CM) occurs sporadically and is associated with Sturge-Weber syndrome (SWS). The somatic mosaic mutation in GNAQ (c.548GàA, p.R183Q) is enriched in endothelial cells (EC) in skin CM and SWS brain CM. Our goal was to investigate how the mutant G-protein a-q subunit (Gaq) alters EC signaling and disrupts capillary morphogenesis. Approach and results: We used lentiviral constructs to express p.R183Q or wild-type GNAQ in normal human endothelial colony forming cells (EC-R183Q and EC-WT respectively). EC-R183Q constitutively activated phospholipase-C β3 (PLCβ3), a downstream effector of Gαq. Activated PLCβ3 was also detected in human CM tissue sections. Bulk RNA-seq analyses of mutant versus wild-type EC indicated constitutive activation of protein kinase C (PKC), NF-κB and calcineurin signaling in EC-R183Q. Increased expression of downstream targets in these pathways, Angiopoetin-2 (ANGPT2), C-X-C Motif Chemokine Ligand 5 (CXCL5) and Down Syndrome Critical Region Protein 1.4 (DSCR1.4) were confirmed by qPCR and immunostaining of human CM tissue sections. The Gαq inhibitor YM-254890 reduced mRNA expression levels of these targets in EC-R183Q while the pan-PKC inhibitor AEB071 reduced ANGPT2 and CXCL5 but not DSCR1.4. EC-R183Q formed enlarged blood vessels in mice, reminiscent of those found in human CM, with robust endothelial ANGPT2. Conclusions: Gaq-R183Q, when expressed in ECs, establishes constitutively active PLCb3 signaling that leads to a pro-angiogenic, pro-inflammatory phenotype. EC-R183Q are sufficient to form CM-like vessels in mice which provides the first evidence that endothelial Gaq-R183Q is causative for CM.
Project description:We used microarray to compare global gene expression profiles between 5 GNAQ/11 mutant uveal melanoma cell lines (GNAQ mutant: 92-1, omm1.3, mel270; GNA11 mutant: omm-gn11 and upmd-1) and 5 GNAQ/11 wild type melanoma cell lines(sk-mel-2, mm415, mm485, sk-mel-5 and mum2c). Uveal melanoma is the most common intraocular tumor that mainly metastasizes to the liver in about 50% patients. Over 80% of UMs harbor GNAQ or GNA11 activating mutation. Currently there is no effective treatment available for UM patients. Results provide insights into downstream signaling of oncogenic GNAQ/11 and identification of therapeutic targets in UM.
Project description:Vascular malformations are congenital lesions caused by somatic and germline mutations that disrupt developmental signaling pathways. Capillary malformations (CMs) typically present as port-wine stains in the skin and can also affect ocular and cerebral tissues in Sturge Weber Syndrome (SWS), leading to aesthetic, neurological, and ophthalmic complications. CMs are caused by a somatic mosaic mutation in the GNAQ gene in endothelial cells, leading to an activating p.R183Q substitution in the Gαq protein. The underlying mechanisms of Gαq-R183Q-driven CMs formation still remain unclear. To address this, we generated CRISPR/Cas9-engineered human dermal microvascular endothelial cells lacking endogenous Gαq, whilst expressing the Gαq-R183Q mutant instead. The Gαq-R183Q mutation strongly impaired endothelial cell migration and angiogenic sprouting capacity compared to wild-type controls. Next, using SILAC-based quantitative proteomics, we investigated the Gαq-R183Q-induced changes in the endothelial phosphoproteome. These analyses revealed prominent activation of calcineurin-NFAT signaling pathway in Gαq-R183Q-expressing endothelial cells, leading to dephosphorylation of NFAT1 and NFAT2 and the selective expression of their transcriptional target DSCR1.4. Immunofluorescence of patient-derived skin biopsies confirmed deregulation of NFAT1/2 and the expression of DSRC1 in endothelial cells, validating their potential importance in CMs. We further demonstrate that pharmacological inhibition of calcineurin with tacrolimus (FK506) could partially restore NFAT signaling, collective cell migration and sprouting in Gαq-R183Q endothelial cells. Intriguingly, the genetic depletion of the NFAT target DSCR1 in Gαq-R183Q cells fully rescued calcineurin/NFAT signaling as well as key endothelial functions. In summary, we uncovered a calcineurin-NFAT-DSCR1.4 signal transduction axis that is driven by Gαq-R183Q and established its importance for endothelial angiogenic properties. These findings highlight that calcineurin/NFAT signaling represents a promising therapeutic target to restore endothelial function in CMs.
Project description:To investigate the transcriptional effects of GNAQ p.Q209L mutation on endothelial cells, bulk RNA-sequencing was performed on endothelial cells lines expressing GNAQ wildtype or mutant Q209L. Cells were also treated with Trametinib or vehicle control to elucidate the specific effects of MAPK/ERK signaling on these cells.
Project description:Cutaneous melanoma (CM) and uveal melanoma (UM) both originate from the melanocytic lineage but are primarily driven by distinct oncogenic drivers, BRAF/NRAS or GNAQ/GNA11 respectively. The melanocytic master transcriptional regulator, MITF, is essential for both CM development and maintenance, but its role in UM is largely unexplored. Here, we use zebrafish models to dissect the key UM oncogenic signaling events, and establish the role of MITF in UM tumors. Remarkably, mitfa deficiency was profoundly UM promoting, dramatically accelerating the onset and progression of tumors induced by Tg(mitfa:GNAQQ209L);tp53M214K/M214K. To further explore the role of MITF in GNAQ-driven tumorigenesis, we performed phospho-proteomics and total proteomics on 5 zebrafish GNAQ Tg(mitfa:GNAQQ209L);tp53M214K/M214K tumors and 5 zebrafish GNAQ Tg(mitfa:GNAQQ209L);tp53M214K/M214K;mitfa-/- tumors.
Project description:Cutaneous melanoma (CM) and uveal melanoma (UM) both originate from the melanocytic lineage but are primarily driven by distinct oncogenic drivers, BRAF/NRAS or GNAQ/GNA11 respectively. The melanocytic master transcriptional regulator, MITF, is essential for both CM development and maintenance, but its role in UM is largely unexplored. Here, we use zebrafish models to dissect the key UM oncogenic signaling events, and establish the role of MITF in UM tumors. Using a melanocytic lineage expression system, we showed that patient-derived mutations of GNAQ (GNAQQ209L) or its upstream CYSLTR2 receptor (CYSLTR2L129Q) both drive UM when combined with a cooperating mutation, tp53M214K/M214K. The tumor-initiating potential of the major GNAQ/11 effector pathways, YAP and PLCβ-ERK, was also investigated in this system, and thus showed that while activated YAP (YAPAA) induced UM with high potency, the patient-derived PLC4 mutation (PLCB4D630Y) very rarely yielded UM tumors in the tp53M214K/M214K context. Remarkably, mitfa deficiency was profoundly UM promoting, dramatically accelerating the onset and progression of tumors induced by Tg(GNAQQ209L);tp53M214K/M214K or Tg(CYSLTR2L129Q);tp53M214K/M214K. Moreover, mitfa loss was sufficient to cooperate with GNAQQ209L to drive tp53-wildtype UM development, and allowed Tg(PLCB4D630Y);tp53M214K/M214K melanocyte lineage cells to readily form tumors. Notably, all of the mitfa-/- UM tumors, including those arising in Tg(mitfa:PLCB4D630Y);tp53M214K/M214K;mitfa-/- fish, displayed nuclear YAP while lacking hyperactive ERK indicative of PLCβ signaling. Collectively, these data show that YAP signaling is the major mediator of UM, and that MITF acts as bona fide tumor suppressor in UM, in direct opposition to its essential role in CM.
Project description:The hair follicle misorientation phenotype in Fzd6-/- mice appears to act through the PCP signaling system, but the downstream effectors of Fzd6 remain mysterious. We used microarrays to search for potential downstream effectors of the Fzd6 signaling pathway in regulating hair follicle orientation.
Project description:The aim of the study was to determine the protein composition of cornified claws of the western clawed frog (Xenopus tropicalis) in comparison to clawless toe tips and back skin. Cornified claws develop on toes I, II, III of the hind limbs, which we refer to as hind limb inner (HI) toes. Toes IV, V of the hind limbs, here referred to as hind limb outer (HO) toes lack claws. Proteins were prepared from HI toe tips including claws, HO toe tips and back skin (BSK) of frogs each (F1, F2, F3) and subjected to proteomic analysis.