Busy signal: platelet-derived growth factor activation in myelofibrosis

A modern overview of the process of platelet formation (thrombocytopoiesis) and its dependence on several factors

Structural and functional alterations in platelets are an actual problem that requires more attention. The treatment of these illnesses proves challenging, inefficient and heavily relies on platelet donations. A difficult task confronting science is producing platelets in vitro, which calls for meticulous examination of factors affecting platelet generation. It is known that megakaryocytes produce platelets in vitro and in vivo differently: in the laboratory we can get a smaller number of platelets compared to the human body. This review primarily examines the stages of megakaryocyte maturation and the processes involved in platelet formation. The article reflects the results of both fundamental research on the problem and the new results obtained over the past decade. Currently, most scientists accept the pro-platelets theory of platelet formation. This review aims to explore in detail each stage of pro-platelet formation and the platelet formation process. It explains on the processes of polyploidization, endomitosis, and apoptosis, as well as the functions of structural cell components (microtubules, mitochondria, T- and α-granules) and pro-platelet migration. The microenvironment influence is acknowledged for the osteoblastic and vascular niches that affect thrombocytopoiesis. The additional aspect is the contribution of specific proteins to thrombocytopoiesis such as RhoA, β1-tubulin, cytokines IL-6, IL-8, Toll-like receptors, etc.

CXCR4-enriched T regulatory cells preferentially home to bone marrow and resolve inflammation

CXCR4 cell surface expression is critical for the homing of T regulatory (Treg) cells to the bone marrow (BM). We hypothesize that CXCR4 enrichment on Tregs cell surface may abbreviate their transit time to reach BM. Umbilical cord-blood CD25+ Tregs underwent CXCR4 dual enrichment and ex vivo expansion using the CRANE process to generate CXCR4-enriched Tregs (TregCXCR4) cells, which showed a faster migration across the Transwell membrane toward CXCL12/stromal cell-derived factor 1α (SDF1α) at 15, 30, and 60 min, when compared to unmanipulated Tregcontrol cells (p < 0.0001). TregCXCR4 exhibited preferential homing to BM in vivo at 12 and 24 h. Metacluster analysis of BM showed a decrease in CD8+ and an increase in CD39 and CD73 and CXCR5 when compared to Tregcontrol. TregCXCR4 decreased plasma TGF-β1/β2 and IFN-γ levels. When compared to control, TregCXCR4 cells decreased in CD8+ T cell, IFN-γ, and TNF-α expression in BM. We conclude that TregCXCR4 show enhanced migration toward CXCL12/SDF1α and a preferential homing to BM resulting in resolution of inflammation.

Exploring the molecular mechanisms between lymphoma and myelofibrosis

Lymphoma is a heterogeneous malignant tumor with an increasing annual incidence. As the lymphoma progresses, bone marrow (BM) invasion gradually appears. Myelofibrosis (MF) can accompany a variety of hematological malignancies, including lymphoma, and multiple myeloma. The prognosis of lymphoma patients with myelofibrosis is poor, and a fundamental reason is that there are few studies on the correlation and pathogenesis of the two diseases. In this review, we examine the potential pathogenesis and the correlation of the two diseases.

Cytokine Profiling in Myeloproliferative Neoplasms: Overview on Phenotype Correlation, Outcome Prediction, and Role of Genetic Variants

Among hematologic malignancies, the classic Philadelphia-negative chronic myeloproliferative neoplasms (MPNs) are considered a model of inflammation-related cancer development. In this context, the use of immune-modulating agents has recently expanded the MPN therapeutic scenario. Cytokines are key mediators of an auto-amplifying, detrimental cross-talk between the MPN clone and the tumor microenvironment represented by immune, stromal, and endothelial cells. This review focuses on recent advances in cytokine-profiling of MPN patients, analyzing different expression patterns among the three main Philadelphia-negative (Ph-negative) MPNs, as well as correlations with disease molecular profile, phenotype, progression, and outcome. The role of the megakaryocytic clone as the main source of cytokines, particularly in myelofibrosis, is also reviewed. Finally, we report emerging intriguing evidence on the contribution of host genetic variants to the chronic pro-inflammatory state that typifies MPNs.

Cytokine Profiling in Myeloproliferative Neoplasms: Overview on Phenotype Correlation, Outcome Prediction, and Role of Genetic Variants

Among hematologic malignancies, the classic Philadelphia-negative chronic myeloproliferative neoplasms (MPNs) are considered a model of inflammation-related cancer development. In this context, the use of immune-modulating agents has recently expanded the MPN therapeutic scenario. Cytokines are key mediators of an auto-amplifying, detrimental cross-talk between the MPN clone and the tumor microenvironment represented by immune, stromal, and endothelial cells. This review focuses on recent advances in cytokine-profiling of MPN patients, analyzing different expression patterns among the three main Philadelphia-negative (Ph-negative) MPNs, as well as correlations with disease molecular profile, phenotype, progression, and outcome. The role of the megakaryocytic clone as the main source of cytokines, particularly in myelofibrosis, is also reviewed. Finally, we report emerging intriguing evidence on the contribution of host genetic variants to the chronic pro-inflammatory state that typifies MPNs.