Project description:Early placenta development involves cytotrophoblast differentiation into extravillous trophoblast (EVT) and syncytiotrophoblast (STB). Defective trophoblast development and function may result in severe pregnancy complications, including fetal growth restriction and pre-eclampsia. The incidence of these complications is increased in pregnancies of fetuses affected by Rubinstein–Taybi syndrome, a developmental disorder predominantly caused by heterozygous mutations in CREB-binding protein (CREBBP) or E1A-binding protein p300 (EP300). Although the acetyltransferases CREBBP and EP300 are paralogs with many overlapping functions, the increased incidence of pregnancy complications is specific for EP300 mutations. We hypothesized that these complications have their origin in early placentation and that EP300 is involved in that process. Therefore, we investigated the role of EP300 and CREBBP in trophoblast differentiation, using human trophoblast stem cells (TSCs) and trophoblast organoids. We found that pharmacological CREBBP/EP300 inhibition blocks differentiation of TSCs into both EVT and STB lineages, and results in an expansion of TSC-like cells under differentiation-inducing conditions. Specific targeting by RNA interference or CRISPR/Cas9-mediated mutagenesis demonstrated that knockdown of EP300 but not CREBBP, inhibits trophoblast differentiation, consistent with the complications seen in Rubinstein–Taybi syndrome pregnancies. By transcriptome sequencing, we identified transforming growth factor alpha (TGFA, encoding TGF-α) as being strongly upregulated upon EP300 knockdown. Moreover, supplementing differentiation medium with TGF-α, which is a ligand for the epidermal growth factor receptor (EGFR), likewise affected trophoblast differentiation and resulted in increased TSC-like cell proliferation. These findings suggest that EP300 facilitates trophoblast differentiation by interfering with at least EGFR signaling, pointing towards a crucial role for EP300 in early human placentation.
Project description:Rubinstein-Taybi syndrome (RTS) is a rare and severe genetic developmental disorder characterized by multiple congenital anomalies and intellectual disability. CREBBP and EP300, the two genes known to cause RTS encode transcriptional coactivators with a catalytic lysine acetyltransferase (KAT) activity. Loss of CBP or p300 function results in a deficit in protein acetylation, in particular at histones. In RTS, nothing is known on the consequences of the loss of histone acetylation on the transcriptomic profiles during neuronal differentiation. To address this question, we differentiated induced pluripotent stem cells from RTS patients carrying a recurrent CREBBP mutation that inactivates the KAT domain into cortical and pyramidal neurons. By comparing their acetylome and their transcriptome at different neuronal differentiation timepoints, we identified 25 specific acetylated histone residues altered in RTS. We also identified the transition between neural progenitors and immature neurons as a critical step of the differentiation process, with a delayed neuronal maturation in RTS.
Project description:Opposing effects of CREBBP mutations during cerebellar development govern the pathogenesis of Rubinstein-Taybi syndrome and adult SHH medulloblastoma
Project description:Recurrent mutations in chromatin modifiers are specifically prevalent in adolescent or adult patients with Sonic Hedgehog-associated medulloblastoma (SHH MB). Here, we report that mutations in the acetyltransferase CREBBP have opposing effects during the development of the cerebellum, the primary site of origin of SHH MB. Our data reveal that loss of Crebbp in cerebellar granule neuron progenitors (GNPs) during embryonic development of mice compromises GNP development, in part by downregulation of brain-derived neurotrophic factor (Bdnf). Interestingly, concomitant cerebellar hypoplasia was also observed in patients with Rubinstein-Taybi syndrome, a congenital disorder caused by germline mutations of CREBBP. By contrast, loss of Crebbp in GNPs during postnatal development synergizes with oncogenic activation of SHH signaling to drive MB growth, thereby explaining the enrichment of somatic CREBBP mutations in SHH MB of adult patients. Together, our data provide novel insights into time-sensitive consequences of CREBBP mutations and corresponding associations with human diseases. We used microarrays to detail the global programme of gene expression underlying the knockout of Crebbp in murine Shh medulloblastoma, acutely induced at postnatal stages of development.
Project description:Recurrent mutations in chromatin modifiers are specifically prevalent in adolescent or adult patients with Sonic Hedgehog-associated medulloblastoma (SHH MB). Here, we report that mutations in the acetyltransferase CREBBP have opposing effects during the development of the cerebellum, the primary site of origin of SHH MB. Our data reveal that loss of Crebbp in cerebellar granule neuron progenitors (GNPs) during embryonic development of mice compromises GNP development, in part by downregulation of brain-derived neurotrophic factor (Bdnf). Interestingly, concomitant cerebellar hypoplasia was also observed in patients with Rubinstein-Taybi syndrome, a congenital disorder caused by germline mutations of CREBBP. By contrast, loss of Crebbp in GNPs during postnatal development synergizes with oncogenic activation of SHH signaling to drive MB growth, thereby explaining the enrichment of somatic CREBBP mutations in SHH MB of adult patients. Together, our data provide novel insights into time-sensitive consequences of CREBBP mutations and corresponding associations with human diseases. We used microarrays to detail the global programme of gene expression underlying the knockout of Crebbp in murine granule neuron precursors, chronically induced at embryonic stages of development.
Project description:Rubinstein-Taybi syndrome (RSTS) is a complex autosomal-dominant disease characterized by mental and growth retardation and skeletal abnormalities. A majority of the individuals diagnosed with RSTS carry heterozygous mutation in the gene CREBBP, but a small percentage of cases are caused by mutations in EP300. To investigate the contribution of p300 to RSTS pathoetiology, we carried out a comprehensive and multidisciplinary characterization of p300+/- mice. These mice exhibited facial abnormalities and impaired growth, two traits associated to RSTS in humans. We also observed abnormal gait, reduced swimming speed, enhanced anxiety in the elevated plus maze, and mild cognitive impairment during the transfer task in the water maze. These analyses demonstratethat p300+/- mice exhibit phenotypes that are reminiscent of neurological traits observed in RSTS patients, but their comparison with previous studies on CBP deficient strains also indicate that, in agreement with the most recent findings in human patients, the activity of p300 in cognition is likely less relevant or more susceptible to compensation than the activity of CBP. To identify those genes whose expression was altered in the hippocampus of p300 deficient mutants, we performed a gene profiling analysis of hippocampal tissue using high-density oligonucleotide microarrays. Experiment Overall Design: We obtained triplicate samples containing total RNA from the hippocampi of four 3-month old females of either genotype (in total 12 p300+/- mice and 12 wild type littermates were used in the experiment).
Project description:Rubinstein-Taybi syndrome (RSTS) is a complex autosomal-dominant disease characterized by mental and growth retardation and skeletal abnormalities. A majority of the individuals diagnosed with RSTS carry heterozygous mutation in the gene CREBBP, but a small percentage of cases are caused by mutations in EP300. To investigate the contribution of p300 to RSTS pathoetiology, we carried out a comprehensive and multidisciplinary characterization of p300+/- mice. These mice exhibited facial abnormalities and impaired growth, two traits associated to RSTS in humans. We also observed abnormal gait, reduced swimming speed, enhanced anxiety in the elevated plus maze, and mild cognitive impairment during the transfer task in the water maze. These analyses demonstratethat p300+/- mice exhibit phenotypes that are reminiscent of neurological traits observed in RSTS patients, but their comparison with previous studies on CBP deficient strains also indicate that, in agreement with the most recent findings in human patients, the activity of p300 in cognition is likely less relevant or more susceptible to compensation than the activity of CBP. To identify those genes whose expression was altered in the hippocampus of p300 deficient mutants, we performed a gene profiling analysis of hippocampal tissue using high-density oligonucleotide microarrays.