Project description:Endoglin (EDG) is a cell surface protein with an important role in the establishment of neo-angiogenesis and vasculogenic mimicry. EDG is part of the transforming growth factor-β (TGF-β) family, acting as an important co-receptor. EDG is shed from the cell surface into the extracellular compartment by matrix metalloproteinase 14 (MMP14), in its soluble form (sEDG). Both transmembrane and soluble forms of EDG exert important signaling functions in the development of new blood vessels and tumour progression. To better understand the role of EDG in Ewing sarcoma (ES), a deadly neoplasm of late childhood and adolescence, we test the efficacy of OMTX703, an endoglin-targeting antibody-drug conjugate in ES8 xenograft. Having determined an optimal dose for OMTX703, an additional experiment was conducted to assess the mechanism(s) of OMTX703 action and its potential mechanism(s) of resistance following a 2-week exposure to OMTX703 at 0, 10, 30, and 60 mg/kg; 246 proteins were assessed by reverse-phase protein array (RPPA). Analysis of variance (ANOVA), Pearson’s correlation as distance metric and Ward’s linkage as the clustering method using a false discovery rate (FDR) of 0.01, identified 60 proteins that discriminated between treatment groups (Matrix#1-Normalized Values). To investigate the proteomic changes associated with the heightened clinical activity of the 60 mg/kg dose, a secondary analysis was performed, which grouped the 10 mg/kg OMTX703 samples and the 10 mg/kg OMTX003 ones with the placebo-treated samples (Matrix#2-Normalized Values). Using a FDR of 0.0001, an absolute log2 fold change of 1.5, Pearson’s correlation as distance metric and Ward’s linkage as the clustering method, 22 proteins were discriminately identified between the 3 treatment groups (Matrix#2-Normalized Values). Notably, a protein regulator of altered metabolism (RPS6) was exclusively upregulated following OMTX703 (60mg/kg), and a second metabolism biomarker (LDHA) was down-expressed in the 30 and 60 mg/kg-treated groups. Conversely, BRD4 was one of about a dozen proteins that were preferentially down-regulated in samples treated only by 60 mg/kg.

Project description:Systemic lupus erythematosus is a chronic autoimmune disease with multifactorial ethiopathogenesis. The complement system is involved in both the early and late stages of disease development and organ damage. To better understand autoantibody mediated complement consumption the GAPAID consortium examined ex vivo immune complex formation on autoantigen arrays. We recruited patients with SLE (n=211), with other systemic autoimmune diseases (n=65) and non-autoimmune control subjects (n=149) in two rheumatology tertiary care centers. Standard clinical and laboratory data were collected from all subjects and serum complement levels were determined in SLE patients. The genotype of SNP rs1143679 in the ITGAM gene was also determined. On-chip formation of immune complexes was examined using a functional immunoassay on autoantigen microarray. The amount of antigen-bound IgM, IgG and complement C4 and C3 was quantified on autoantigens comprising nucleic acids, proteins and lipids. Our results show that the relatively high complement consumption of nucleic acids is further increased upon binding of IgM and IgG. This is true even when serum complement levels are decreased due to complement consumption in SLE patients. A negative correlation between serum complement levels and ex vivo complement deposition on nucleic acid autoantigens is demonstrated. On the contrary, most protein and lipid autoantigens show positive correlation with C4 and C3 levels. Genetic analysis reveals that the non-synonymous variant rs1143679 in complement receptor type 3 is associated with an increased production of anti-dsDNA IgG antibodies. Notwithstanding, homozygous carriers of the previously reported susceptible allele (AA) have lower levels of dsDNA specific IgM among SLE patients. Regarding organ involvement we find that besides anti-C1q IgG, low levels of dsDNA specific IgM and low complement C4 binding to C1q are also associated with renal injury. In summary, nucleic acids maintain a skewed complement deposition balance when bound by IgG and IgM, depleting the early classical complement pathway from other physiological processes. Dysfunction of the receptor responsible for complement-mediated apoptotic debris removal promotes the development of autoantibodies targeting nucleic acids. These observations provide serological and genetic evidence for complement-mediated clearance deficiency of apoptotic debris in lupus.

Dataset Information

Phosphoproteomics

Similar Datasets

OmicsDI is part of the ELIXIR infrastructure

Tweets