Mapping the transcriptional and mutation landscape of the malignant hematopoietic clone in interaction with fibrosis-driving stromal cells in myeloproliferative neoplasms

• Applicant: Professorin Dr. Rebekka Schneider-Kramann
• Subject Area: Hematology, Oncology
• Term: since 2023
• Project identifier: Deutsche Forschungsgemeinschaft (DFG) - Project number 514007497

In our previous work, we focused on the identification of fibrosis-driving cells and on mechanisms driving their fibrotic transformation. Using single cell RNA sequencing data in murine disease models and patient samples, we inferred an altered cross-talk between hematopoietic cells and fibrosis-driving stromal cells but information on direct cellular crosstalk but the relevance of MPN driver and co-mutations was lacking. In the proposed project, we will 1) focus on (co)mutated hematopoietic cells and their progeny in the activation of fibrosis-driving cells and 2) gain detailed insights into the cellular cross-talk including the physical interaction of (co)mutated and fibrosis-driving cells. In objective 1, we plan to map the transcriptional and mutation landscape of the fibrosis-inducing MPN clone in interaction with fibrosis-driving stromal cells through combined scRNA sequencing and target genotyping of driver and secondary MPN mutations as well as genotyping of mitochondrial variants. We hypothesize that the sequence of mutations occurring in HSCs determines the stepwise fibrotic progression which we determined in preliminary work. Co-mutations (e.g. ASXL1, EZH2) in the MPN clone have been associated with a higher degree of fibrosis. Here, we will map the effect of driver and secondary mutations on lineage bias and transcriptional changes in hematopoietic clones, and will characterize inflammatory processes and cells associated with MF progression (fibrosis-inducing and -driving cells). In objective 2, we aim to dissect the cellular crosstalk of physically interacting fibrosis-inducing mutated hematopoietic cells and fibrosis-driving cells by doublet cell sorting followed by single cell sequencing (physically interacting cells - PIC-seq). We will focus on cellular interactions and physically interacting cells (stroma-hematopoiesis; PIC seq) as i) physically interacting cells are more likely to talk to each other and ii) certain pathways require physical interaction (e.g. Notch signaling, integrin signaling) in our established murine and patient samples.

• DFG Programme: Research Grants
• Co-Investigators: Professor Dr. Ivan Gesteira Costa Filho; Professor Dr. Steffen Koschmieder