Journal Article

Activation of integrin signaling up-regulates pro-inflammatory cytokines in JAK2-V617F positive hematopoietic cells

Haage, Tobias R., Bhuria, Vikas, Hakobyan, Mariam, Weinert, Sönke, Baldauf, Conny K., Fahldieck, Corinna, Böttcher, Martin, Angenstein, Alexa, Fischer, Thomas, Schraven, Burkhart, Mougiakakos, Dimitrios, Lipka, Daniel B.

2025

Overview

Background The JAK2-V617F mutation is the most frequent driver mutation in a group of malignant hematopoietic disorders called myeloproliferative neoplasms (MPN). JAK2-V617F is a somatic mutation originating in a hematopoietic stem cell and results in constitutively activated JAK-STAT signaling. High levels of pro-inflammatory cytokines in the blood are a hallmark of MPN patients and are a key factor in the severe clinical symptoms seen in these patients. The molecular mechanisms underlying the up-regulation of inflammatory cytokines in JAK2-V617F mutated hematopoietic cells remain to be elucidated. Methods 32D myeloid progenitor cells expressing JAK2-wildtype (WT) and JAK2-V617F, respectively were employed. In addition, primary hematopoietic cells from the JAK2-V617F knock-in MPN mouse model were investigated. Integrin outside-in signaling upon binding of cells to the adhesion molecules VCAM-1/ICAM-1 was characterized by Western blotting of phosphorylated FAK, STAT3, p65, SYK and JNK. Regulation of mRNA and protein expression of IL-1α, IL-1β, IL-6, TNF and CXCL10 was measured by qPCR and ELISA. RNAseq and DNA methylation analysis in primary mouse JAK2-V617F granulocytes was performed. In JAK2-V617F knock-in mice, anti-integrin treatment was applied to evaluate the impact of activated integrin signaling on IL-1 blood levels in vivo. Results Integrin stimulation via the adhesion molecules VCAM-1/ICAM-1 activated integrin outside-in signaling including FAK, SYK, NFκB, and JNK. This induced strong mRNA expression of IL-1α, IL-1β, IL-6, TNF and CXCL10. In 32D cells, the presence of the JAK2-V617F mutation further increased VCAM-1/ICAM-1-induced mRNA and protein levels of IL-1α and IL-1β, and active caspase 1 expression. In primary granulocytes, integrin stimulation resulted in an activated mRNA signature of inflammatory cytokines. Consistent with the mRNA results, adhesion to VCAM-1/ICAM-1 induced an increase in intracellular IL-1α and IL-1β protein levels in 32D cells. However, in primary hematopoietic cells, up-regulation of inflammatory cytokines was not observed at the protein level in vitro, whereas, in vivo, blocking of integrin binding to VCAM-1/ICAM-1 was sufficient to reduce elevated IL-1α levels in the blood of JAK2-V617F mice. Conclusions We conclude that integrin stimulation via the adhesion molecules VCAM-1/ICAM-1 activates integrin outside-in signaling, leading to the up-regulation of pro-inflammatory cytokines in both JAK2-mutated and non-mutated mouse hematopoietic cells.

• Publisher: BioMed Central,BioMed Central Ltd,Springer Nature B.V,BMC
• Subject: Adhesion / Animals / Antibodies / Biomedical and Life Sciences / Blood levels / Bone marrow / Caspase-1 / Cell adhesion molecules / Cell Biology / Cellular signal transduction / CXCL10 protein / Cytokines / Cytokines - genetics / Cytokines - metabolism / Cytokines and Growth Factors / Development and progression / DNA methylation / Gene expression / Gene mutations / Genetic aspects / Granulocytes / Health aspects / Hematopoietic stem cells / Hematopoietic Stem Cells - metabolism / Humans / ICAM-1 / IL-1β / Inflammation / Integrins / Integrins - metabolism / Intercellular adhesion molecule 1 / Interleukin 6 / JAK2-V617F / Janus kinase 2 / Janus Kinase 2 - genetics / Janus Kinase 2 - metabolism / Kinases / Leukocytes (granulocytic) / Life Sciences / Ligands / Mice / Molecular modelling / Mutation / Myeloproliferative disorders / Myeloproliferative Disorders - genetics / NF-κB protein / Patients / Pro-inflammatory cytokines / Progenitor cells / Protein-Ligand Interactions / Quality of life / Receptors / Signal Transduction / Stat3 protein / Stem cells / Syk protein / Tumors / Up-Regulation / Vascular cell adhesion molecule 1 / VCAM-1 / Western blotting