The elucidation of molecular mechanisms in systemic mastocytosis

Mcmullen, Amy Anne (2018) The elucidation of molecular mechanisms in systemic mastocytosis. Masters by Research thesis (MSc), Manchester Metropolitan University.

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Abstract

Mastocytosis, one of the subcategories of myeloproliferative neoplasms, results from a colonel, neoplastic proliferation of morphologically and immunophenotypically abnormal mast cells which accumulate primarily in the skin and bone marrow. Prevalence is reported to be 13 in 100,000 of the population, with an equal male to female preponderance. The clinical spectrum is heterogeneous and ranges from relatively benign cutaneous mastocytosis (CM), with isolated skin lesions, to a more aggressive variant, systemic mastocytosis (SM). To carry out both a global discovery and a targeted analysis of the proteome of plasma from peripheral blood of systemic mastocytosis patients and compare to healthy controls, to understand the molecular mechanism of systemic mastocytosis and to identify novel disease biomarkers. Peripheral blood was collected by venepuncture at the antecubital fossa from systemic mastocytosis patients (n=13) and healthy controls (n=7). Following immune-depletion of high abundance proteins and tryptic digestion, plasma samples were loaded onto a SciEx 6600 Triple TOF mass-spectrometer. SWATH-MS identified 1437 proteins, off which 360 were upregulated. Further analysis identified these as being involved in immune system regulation and leukocyte activation. ELISA was used to measure the levels of proteins common to all pathways involved in immune regulation and inflammation. The results of ELISA demonstrated significantly increased circulating plasma levels of CRP, CXCL7, LBP, TGFb1 and PDGFrb in systemic mastocytosis compared to controls. Circulating plasma levels of B2M were also increased in patients, although this did not reach the level of statistical significance. The results of the current investigation demonstrate, the up-regulated proteins identified are involved in immune system regulation and inflammation, suggesting a central role of the inflammatory response in the patho-physiology of systemic mastocytosis.