Project description:Genetic variants in LZTR1 are associated with the development of Noonan syndrome. Here, we analyzed the proteome of cultured cardiomyocytes derived from hiPSCs with a pathological homozygous LZTR1 variant L580P in comparison to two wild type iPSC lines.
Project description:Genetic variants in LZTR1 are associated with the development of Noonan syndrome. Here, we analyzed the proteome of cultured cardiomyocytes derived from hiPSCs with a pathological homozygous LZTR1 variant L580P in comparison to heterozygous and homozygous CRISPR/Cas9-corrected iPSC lines.
Project description:• Activating mutations of Shp2 cause conditions such as Noonan syndrome and juvenile myelomonocytic leukemia (JMML), with unmet therapeutic needs. • SFX-01, a sulforaphane complex, modifies cysteine residues and targets proteins including Shp2, where it induces an inhibitory modification at the active site of this protein phosphatase. • In a transgenic mouse model of Noonan syndrome and human JMML stem cells, SFX-01 normalized Shp2 activity, reduced myeloid cell counts, and induced cell-cycle arrest, highlighting its therapeutic potential.
Project description:Juvenile myelomonocytic leukemia (JMML) is an aggressive myeloproliferative neoplasm of early childhood with a poor survival rate thus there is a requirement for improved treatment strategies. Induced pluripotent stem cells offer the ability to model disease and develop new treatment strategies. JMML is frequently associated with mutations in PTPN11. Children with Noonan syndrome, a development disorder, have an increased incidence of JMML associated with specific germline mutations in PTPN11. We undertook a proteomic assessment of myeloid cells derived from induced pluripotent stem cells obtained from Noonan syndrome patients with PTPN11 mutations, either associated or not associated with increased incidence of JMML. We report that the proteomic perturbations induced by the leukaemia-associated PTPN11 mutations are associated with TP53 and NF-ĸb signalling. We have previously shown that MYC is involved in the differential gene expression observed in Noonan syndrome patients associated with increased incidence of JMML. Thus, we employed drugs to target these pathways and demonstrate differentential effects on clonogenic hematopoietic cells derived from Noonan syndrome patients whom develop JMML and those who do not. Further, we demonstrated these small molecular inhibitors, JQ1 and CBL0137, preferentially extinguish primitive haematopoietic cells from sporadic JMML patients as opposed to cells from healthy individuals.
Project description:Childhood-onset myocardial hypertrophy and cardiomyopathic changes are associated with significant morbidity and mortality early in life, particularly in patients with Noonan syndrome, a multisystemic genetic disorder caused by autosomal dominant mutations in genes of the Ras-MAPK pathway. Although the cardiomyopathy associated with Noonan syndrome (NS-CM) shares certain cardiac features with the hypertrophic cardiomyopathy caused by mutations in sarcomeric proteins (HCM), such as pathological myocardial remodeling, ventricular dysfunction and increased risk for malignant arrhythmias, the clinical course of NS-CM significantly differs from HCM. This suggests a distinct pathophysiology that remains to be elucidated. Here, by analysis of sarcomeric myosin conformational states, histopathology and gene expression in left ventricular myocardial tissue from NS-CM, HCM and normal hearts complemented with disease modeling in cardiomyocytes differentiated from patient-derived PTPN11N308S/+ induced pluripotent stem cells, we demonstrate distinct disease phenotypes between NS-CM and HCM and uncover cell cycle defects as a potential driver of NS-CM.
Project description:Activating mutations of Src homology-2 domain-containing protein tyrosine phosphatase-2 (Shp2) cause multiple childhood conditions for which there is an unmet therapeutic need, including juvenile myelomonocytic leukemia (JMML) and Noonan syndrome. Using unbiased proteomics, the protein targets of SFX-01, an α-cyclodextrin-stabilized isothiocyanate complex that covalently adducts cysteines that is in clinical development, were identified and included Shp2. SFX-01 induced an inhibitory dithiolethione modification at the Shp2 active site cysteine. Importantly, in a transgenic mouse model of human Noonan syndrome with hyperactive D61G Shp2, SFX-01 concomitantly normalised their phosphatase activity and myeloid cell count. Furthermore, SFX-01 also attenuated JMML human patient-derived hematopoietic stem cell proliferation that was linked to STAT1 signaling and decreased cyclin D1 expression, resulting in cell-cycle arrest. We conclude that SFX-01 is an activating mutant Shp2 inhibitor and may offer beneficial effects in patients with JMML or Noonan syndrome.
Project description:Hematopoietic stem and progenitor cells derived from a zebrafish model of Noonan syndrome, carrying a patient-associated Shp2-D61G mutation, display an expansion of monocyte/macrophage progenitors with an inflammatory gene expression signature.