Rong Fan, Ph.D. Department of Biomedical Engineering Yale University Hematologic myeloproliferative disorders (MPDs) are neoplastic, clonal blood diseases in which a dysregulated excessive or dysplastic production of blood cells was induced by the gain-of-function mutations (e.g., JAK2). While the common mutations of MPDs have been identified and the mutation pattern is relatively uniform across patients, the clinical outcomes vary substantially. Patients with myeloproliferative malignancies are characterized by a systemic inflammatory response notable for high levels of circulating pro-inflammatory cytokines associated with the development of symptoms (e.g., splenomegaly) and reduced overall survival. Therefore it is believed that the cytokine-secreting cells in bone marrow are mechanistically linked to the pathogenesis and therapeutic response of MPD. Yet the exact mechanism remains unclear due to (1) the large degree of cellular heterogeneity in the bone marrow compartment, (2) the diverse cytokine functions in individual bone marrow cells, and (3) the difficulty to perform informative molecular characterization from limited needle biopsy specimens. Recently, our laboratory developed an innovative microchip platform for high-throughput, highly multiplex (42-plex) detection of cytokine secretion at a single-cell level. This technology represents the highest multiplexing recorded to date in terms of single-cell protein secretion assay. It requires very small quantities of cells (~ 1000 cells) as the input and thus is uniquely suited for examining clinical biopsy specimens. We conducted single-cell cytokine profiling on hematopoietic cells including stem/progenitor and lineage-committed cells from JAK2 mutation murine models and patients with myelofibrosis. Principal component analysis (PCA) of cytokine spectra in all single hematopoietic cells reveals that the cytokine functions of “normal” non-mutant hematopoietic cells were significantly skewed and contributed substantially to MPD pathogenesis. Interestingly, mutation-specific deletion of STAT3, a master transcription factor controlling the secretion of a host of cytokines, has little effect on disease trajectory. JAK inhibitor treatment has to suppress both malignant and non-malignant hematopoietic cells to achieve therapeutic benefit. This work demonstrated the power of our single-cell technology to characterize functional cellular heterogeneity in disease lesion and revealed an unexpected crucial role of “normal” hematopoietic cells in MPD pathogenesis and therapeutic response.
Biomedical Engineering Seminar - “Are you infected? Using breath to diagnose acute lung infection and exposure”
Thursday, April 17, 2014 2:00pm - 3:00pm