O-048 Proteomics analysis on human cerebral cavernous malformations reveals novel biomarkers for the disease pathology

Abstract

<h3>Background</h3> Cerebral cavernous malformations (CCM) are abnormal cystic capillaries with an impaired signaling in endothelial cells originating from venous/capillary bed. They can appear as a sporadic or familial form, caused by somatic and/or inherited loss-of-function mutations in one of risk genes, CCM1–3, or other mutations. They are associated with an elevated risk of focal neurological deficits, seizures and hemorrhagic stroke. In this study, we analyzed protein expression signature in human CCM tissue samples by using highly specific and sensitive multiplexing technique, proximity extension assay (PEA) in Olink platform. <h3>Methods</h3> Relative expression of 184 biomarkers were analyzed from fresh-frozen CCM lesion samples (n=6; age 3–66 years; male:female ratio 2:4) and brain tissue controls from normal cerebral cortex (n=3; age 34–69 years; male:female ratio 2:1; Amsbio, Abington, UK) using Olink Target 96 Cardiovascular III and Inflammation panels. In addition, in 2 CCMs, protein extraction was done by separating tissue from the lesion area and the surrounding brain tissue representing normal caliber brain vasculature; thus, allowing analysis of biomarkers in a spatially resolving manner. <h3>Results</h3> Data analysis revealed 76 biomarkers with significantly higher expression in CCM lesion than control brain tissue. These biomarkers belong to pathways previously connected to CCM pathogenesis (e.g. endothelial-to-mesenchymal transition, toll-like receptor signaling); in addition, novel pathways (neutrophil-extracellular-trap formation, coagulation cascade and NFkB signaling) were defined. Biomarker expression profiles were in-line with disease severity, representing higher level of especially inflammatory markers in ruptured (n=3) than non-ruptured (n=3) samples. Furthermore, biomarkers involved in compensatory mechanisms were defined from the CCM border area (n=2). <h3>Conclusions</h3> Here, we present a novel technique for proteomics analysis on human CCMs, offering a possibility for high-throughput screening from small amount of fresh-frozen tissue. Biomarkers detected here will advance our understanding of the causes and mechanisms of CCM and help later development of new, targeted treatment strategies. <h3>Disclosures</h3> <b>S. Jauhiainen:</b> None. <b>F. Onyeogaziri:</b> None. <b>H. Savander:</b> None. <b>F. Lazzaroni:</b> None. <b>L. Liu Conze:</b> None. <b>A. Laakso:</b> None. <b>M. Niemelä:</b> None. <b>E. Dejana:</b> None. <b>B. Rezai Jahromi:</b> None. <b>P. Magnusson:</b> None.