Biology subjects

Bader, M. S.

Publications and source records attributed to Bader, M. S..

2 recordsLinked to original sources

bioRxiv2023

IL-1β promotes MPN disease initiation by favoring early clonal expansion of JAK2-mutant hematopoietic stem cells

JAK2-V617F is the most frequent somatic mutation causing myeloproliferative neoplasm (MPN). However, JAK2-V617F can also be found in healthy individuals with clonal hematopoiesis of indeterminate potential (CHIP) with a frequency much higher than the prevalence of MPN. The factors controlling the conversion of JAK2-V617F CHIP to MPN are largely unknown. We hypothesized that IL-1{beta} mediated inflammation is one of the factors that favors this progression. We examined mono- or oligoclonal evolution of MPN by performing bone marrow transplantations at limiting dilutions with only 1-3 JAK2-mutant HSCs per recipient. Genetic loss of IL-1{beta} in JAK2-mutant hematopoietic cells or inhibition by a neutralizing anti-IL-1{beta} antibody restricted the early clonal expansion of these JAK2-mutant HSCs resulting in a reduced frequency of a CHIP-like state and a lower rate of conversion to MPN. The MPN disease-promoting effects of IL-1{beta} were associated with damage to sympathetic innervation leading to loss of nestin-positive mesenchymal stromal cells and required the presence of IL-1R1 on bone marrow stromal cells. The anti-IL-1{beta} antibody protected these mesenchymal stromal cells from IL-1{beta} mediated damage and limited the expansion of the JAK2-mutant clone. Our results identify IL-1{beta} as a potential therapeutic target for preventing the transition from JAK2-V617F CHIP to MPN. Brief summaryIn a mouse model of oligo-clonal myeloproliferative neoplasm (MPN), IL-1{beta} produced by JAK2-mutant cells favored expansion of sub-clinical JAK2-V617F clones and initiation of MPN disease.

cancer biology↗

bioRxiv2022

Impact of clonal architecture on clinical course and prognosis in patients with myeloproliferative neoplasms

Myeloproliferative neoplasms (MPNs) are caused by a somatic gain-of-function mutation in one of three "disease driver" genes JAK2, MPL or CALR. About half of MPN patients also carry additional somatic mutations that modify the clinical course. The order of acquisition of these gene mutations has been proposed to influence the phenotype and evolution of the disease. We studied 50 JAK2-V617F-positive MPN patients who carried at least one additional somatic mutation and determined the clonal architecture of their hematopoiesis by sequencing DNA from single cell derived colonies. In 22 of these patients we also side-by-side applied Tapestri single-cell DNA sequencing (scDNAseq) with cells from the same blood sample. The clonal architectures derived by the two methods showed good overall concordance. scDNAseq showed higher sensitivity for mutations with low variant allele fraction, but had more difficulties distinguishing between heterozygous and homozygous mutations. By unsupervised analysis of clonal architecture data from all 50 MPN patients we defined 4 distinct clusters that differed by the order of acquisition of the mutations, and the complexity of the subclonal structure. Cluster 4, characterized by more complex subclonal structure without a preferred order of acquisition, correlated with reduced overall survival, and in multivariate analysis represented a risk factor independent of the MPN subtype or the age at diagnosis. Our results suggest that deciphering the clonal architecture in patients with MPN that carry multiple gene mutations can improve the molecular prognostic stratification that until now was primarily based on the number and type of gene mutations.

cancer biology↗