Transcriptomic comparison of bone marrow CD34 + cells and peripheral blood neutrophils from ET patients with JAK2 or CALR mutations

Abstract

Background Essential thrombocythemia (ET) is one of the most common types of Ph-negative myeloproliferative neoplasms, an infrequent group of blood cancers that arise from a CD34 + hematopoietic stem cell (HSC) in the bone marrow (BM) primarily due to driver mutations in JAK2, CALR or MPL. These aberrations result in an overproduction of mature myeloid cells in peripheral blood (PB). To date, no targeted therapies have been approved for ET patients, so the study of the molecular mechanisms behind the disease and the identification of new therapeutic targets may be of interest. For this reason, in this study, we have compared the transcriptomic profile of undifferentiated CD34 + cells and mature myeloid cells from ET patients (CALR and JAK2-mutated) and healthy donors deposited in publicly available databases. The study of the similarities and differences between these samples might help to better understand the molecular mechanisms behind the disease according to the degree of maturation of the malignant clone and the type of mutation and ultimately help identify new therapeutic targets for these patients. Results The results show that most of the altered hallmarks in neutrophils were also found in CD34 + cells. However, only a few genes showed a similar aberrant expression pattern in both types of cells. We have identified a signature of six genes common to patients with CALR and JAK2 mutations (BPI, CRISP3, LTF, MMP8, and PTGS1 upregulated, and PBXIP1 downregulated), a different signature of seven genes for patients with CALR mutations (BMP6, CEACAM8, ITK, LCN2, and PRG2 upregulated, and MAN1A1 and MME downregulated) and a signature of 13 genes for patients with JAK2 mutations (ARG1, CAST, CD177, CLEC5A, DAPP1, EPS15, IL18RAP, OLFM4, OLR1, RIOK3, SELP, and THBS1 upregulated, and IGHM downregulated). Conclusions Our results highlight transcriptomic similarities and differences in ET patients according to the degree of maturation of the malignant clone and the type of mutation. The genes and processes altered in both CD34 + cells and mature neutrophils may reveal altered sustained processes that could be studied as future therapeutic targets for ET patients.

PBX1: a TALE of two seasons—key roles during development and in cancer

“…Primitive hematopoiesis (Chung et al, 2021); erythropoietic cell lineage specification, myelopoiesis inhibition (Pillay et al, 2010); definitive hematopoiesis (DiMartino et al, 2001) In a murine model of Myeloproliferative Neoplasm (MPN), it drives thrombocytosis and erythrocytosis; aberrant expression in MPN patients' cells (Shepherd et al, 2018;Muggeo et al, 2021;Guijarro-Hernández and Vizmanos, 2023) Murine Mk development (Pillay et al, 2010;Cullmann et al, 2021); human Mk differentiation (Okada et al, 2003) Postnatal: HSC quiescence and lineage priming; erythroid and lymphoid differentiation (Ficara et al, 2008;Ficara et al, 2013) B cell development (Sanyal et al, 2007) Hodgkin lymphoma: reactivation of B cell progenitor-genes (Nagel et al, 2021); ETS1 inhibition, JAK2 activation (Nagel et al, 2023) B-ALL (Yin et al, 2023), B-LBL (Kubota-Tanaka et al, Okura et al, 2020): E2A-PBX1 translocation…”

“…In silico analysis revealed an inverse correlation between the genes differentially expressed (DE) in human MPN and those DE in Pbx1-null HSCs (Muggeo et al, 2021), providing further evidence of the involvement of PBX1 in human MPN. In addition, PBXIP1 (PBX homeobox interacting protein 1), which codes for a protein that inhibits the transcriptional activation potential of PBX1 by preventing its binding to DNA, is downregulated in MPN patients (Guijarro-Hernández and Vizmanos, 2023). The positive regulation of STAT3 transcription by PBX1 binding to its promoter that has been reported in other tissues (Jung et al, 2016) might represent the underlying mechanism through which its expression contributes to MPN development/ maintenance; STAT3, part of the JAK/STAT pathway that acts as an effector of the mutations causing MPN, is widely expressed within the hematopoietic system and its transcription is downregulated in the absence of PBX1 in purified HSCs (Ficara et al, 2008).…”

Immunophenotype of myeloid granulocytes in Chinese patients with BCR::ABL1-negative myeloproliferative neoplasms

“…Angiogenic factors of granulocytes were significantly reduced in MPN patients after hydroxyurea treatment [ 9 ]. Most of the altered markers in neutrophils were also found in CD34+ cells from patients with CALR and JAK2 mutations, but only a few genes showed similar expression patterns in both cell types [ 10 ]. Downstream of gene regulation, protein expression of integrin CD11b, tissue factor (TF) and leucocyte alkaline phosphatase were increased in JAK2V617F compared to CALR granulocytes [ 11 – 14 ].…”