Andrzej Eljaszewicz

The Role of Different Monocyte Subsets in the Pathogenesis of Atherosclerosis and Acute Coronary Syndromes

The inflammation underlying both atherosclerosis and acute coronary syndromes is strongly related to monocyte‐related actions. However, different monocyte subsets can play differential roles in the formation and destabilization of atherosclerotic plaque as well as healing of damaged myocardial tissue. Monocytes are currently being divided into three functionally distinct subsets with different levels of CD14 (cluster of differentiation 14) and CD16 expression. Thus, there are classical CD14++CD16‐, intermediate CD14++CD16+ and non‐classical CD14+CD16++ monocytes. Here, we summarize the current knowledge on complex activities of different monocyte subsets in atherosclerosis and acute coronary syndromes. Moreover, we discuss which monocyte subsets can serve either as predictive biomarkers of cardiovascular risk or as potential targets used in atherosclerosis and its complications.

MicroRNA modulators of epigenetic regulation, the tumor microenvironment and the immune system in lung cancer

Cancer is an exceedingly complex disease that is orchestrated and driven by a combination of multiple aberrantly regulated processes. The nature and depth of involvement of individual events vary between cancer types, and in lung cancer, the deregulation of the epigenetic machinery, the tumor microenvironment and the immune system appear to be especially relevant. The contribution of microRNAs to carcinogenesis and cancer progression is well established with many reports and investigations describing the involvement of microRNAs in lung cancer, however most of these studies have concentrated on single microRNA-target relations and have not adequately addressed the complexity of their interactions. In this review, we focus, in part, on the role of microRNAs in the epigenetic regulation of lung cancer where they act as active molecules modulating enzymes that take part in methylation-mediated silencing and chromatin remodeling. Additionally, we highlight their contribution in controlling and modulating the tumor microenvironment and finally, we describe their role in the critical alteration of essential molecules that influence the immune system in lung cancer development and progression.

High-dose bee venom exposure induces similar tolerogenic B-cell responses in allergic patients and healthy beekeepers.

The involvement of B cells in allergen tolerance induction remains largely unexplored. This study investigates the role of B cells in this process, by comparing B‐cell responses in allergic patients before and during allergen immunotherapy (AIT) and naturally exposed healthy beekeepers before and during the beekeeping season.

Synthesis and anti-inflammatory activity of new 1,2,4-triazole derivatives

The series of new 1,2,4-triazole derivatives with methacrylic acid moiety were synthesized and characterized by NMR and IR spectroscopy as well as X-ray crystallography. The influence of newly synthesized compounds on the inflammation on the level of cytokine production and the proliferation of human peripheral blood mononuclear cells (PBMC) were experimentally evaluated. Obtained triazoles showed antiproliferative activity and diverse effects on cytokine production. Two compounds demonstrated potentially anti-inflammatory activity and comparable effects with ibuprofen.

Effective Mobilization of Very Small Embryonic-Like Stem Cells and Hematopoietic Stem/Progenitor Cells but Not Endothelial Progenitor Cells by Follicle-Stimulating Hormone Therapy

Recently, murine hematopoietic progenitor stem cells (HSCs) and very small embryonic-like stem cells (VSELs) were demonstrated to express receptors for sex hormones including follicle-stimulating hormone (FSH). This raised the question of whether FSH therapy at clinically applied doses can mobilize stem/progenitor cells in humans. Here we assessed frequencies of VSELs (referred to as Lin−CD235a−CD45−CD133+ cells), HSPCs (referred to as Lin−CD235a−CD45+CD133+ cells), and endothelial progenitor cells (EPCs, identified as CD34+CD144+, CD34+CD133+, and CD34+CD309+CD133+ cells) in fifteen female patients subjected to the FSH therapy. We demonstrated that FSH therapy resulted in statistically significant enhancement in peripheral blood (PB) number of both VSELs and HSPCs. In contrast, the pattern of responses of EPCs delineated by different cell phenotypes was not uniform and we did not observe any significant changes in EPC numbers following hormone therapy. Our data indicate that FSH therapy mobilizes VSELs and HSPCs into peripheral blood that on one hand supports their developmental origin from germ lineage, and on the other hand FSH can become a promising candidate tool for mobilizing HSCs and stem cells with VSEL phenotype in clinical settings.

Novel evidence that pituitary gonadotropins directly stimulate human leukemic cells-studies of myeloid cell lines and primary patient AML and CML cells

We recently reported that normal hematopoietic stem cells express functional pituitary sex hormone (SexH) receptors. Here we report for the first time that pituitary-secreted gonadotrophins stimulate migration, adhesion, and proliferation of several human myeloid and lymphoid leukemia cell lines. Similar effects were observed after stimulation of human leukemic cell lines by gonadal SexHs. This effect seems to be direct, as the SexH receptors expressed by leukemic cells responded to stimulation by phosphorylation of MAPKp42/44 and AKTser473. Furthermore, in parallel studies we confirmed that human primary patient-derived AML and CML blasts also express several functional SexH receptors. These results shed more light on the potential role of SexHs in leukemogenesis and, in addition, provide further evidence suggesting a developmental link between hematopoiesis and the germline.

Vitamin D3 Treatment Decreases Frequencies of CD16-Positive and TNF-α-Secreting Monocytes in Asthmatic Patients

Background: Previously, we demonstrated that glucocorticoid (GC) treatment of asthmatic patients resulted in decreasing frequencies of monocyte subsets expressing CD16 and capable of releasing TNF-α. Here, we wished to analyze whether the active form of vitamin D, i.e. vitamin D₃, referred to as 1α,25-dihydroxyvitamin D₃ [1,25-(OH)₂D₃] can exert GC-like proapoptotic effects on CD16-positive monocytes and thus decrease the proinflammatory potential of these cells. Finally, we set out to investigate whether the addition of 1,25-(OH)₂D₃ would facilitate the use of lower doses of GC without decreasing their anti-inflammatory properties. Methods: Peripheral blood mononuclear cells collected from healthy individuals and asthmatic patients were cultured with 1,25-(OH)₂D₃ and/or varying doses of GC in the presence or absence of caspase inhibition. The cells were either directly stained for extracellular markers or prestimulated with lipopolysaccharide for the assessment of intracellular cytokine production and then analyzed by flow cytometry. Results: We found that 1,25-(OH)₂D₃ alone (and in combination with GC) decreased the frequency of CD14++CD16+ and CD14+CD16++ monocytes from asthmatic patients and significantly diminished TNF-α production by the monocytes. With regard to the CD14+CD16++ subset, the monocyte-depleting effects of 1,25-(OH)₂D₃ were abrogated in the presence of pan-caspase inhibitor, suggesting a proapoptotic mechanism of 1,25-(OH)₂D₃ action. Interestingly, we found that a combined treatment of 1,25-(OH)₂D₃ and GC allowed for a 5-fold reduction of the GC dose while maintaining their anti-inflammatory effects. Conclusions: This study has revealed novel immunomodulatory properties of 1,25-(OH)₂D₃ directed against monocyte subsets capable of TNF-α production. In addition, our data suggest that the introduction of 1,25-(OH)₂D₃ to anti-inflammatory therapy would possibly allow for the use of lower doses of GC.

Effect of Periodic Granulocyte Colony-Stimulating Factor Administration on Endothelial Progenitor Cells and Different Monocyte Subsets in Pediatric Patients with Muscular Dystrophies.

Muscular dystrophies (MD) are heterogeneous group of diseases characterized by progressive muscle dysfunction. There is a large body of evidence indicating that angiogenesis is impaired in muscles of MD patients. Therefore, induction of dystrophic muscle revascularization should become a novel approach aimed at diminishing the extent of myocyte damage. Recently, we and others demonstrated that administration of granulocyte colony-stimulating factor (G-CSF) resulted in clinical improvement of patients with neuromuscular disorders. To date, however, the exact mechanisms underlying these beneficial effects of G-CSF have not been fully understood. Here we used flow cytometry to quantitate numbers of CD34+ cells, endothelial progenitor cells, and different monocyte subsets in peripheral blood of pediatric MD patients treated with repetitive courses of G-CSF administration. We showed that repetitive cycles of G-CSF administration induced efficient mobilization of above-mentioned cells including cells with proangiogenic potential. These findings contribute to better understanding the beneficial clinical effects of G-CSF in pediatric MD patients.

Involvement of BAFF and APRIL in Resistance to Apoptosis of Acute Myeloid Leukemia

B-cell activation factor of the TNF family (BAFF), and a proliferation-inducing ligand (APRIL), two members of the tumour necrosis factor (TNF) superfamily, beyond playing a significant role in normal B-cell development, promote survival and proliferation of malignant B cells. Both ligands interact with 3 receptors: BAFF-R, specific to BAFF, and TACI and BCMA which are shared by both BAFF and APRIL. Here we wished to investigate the potential role of these proteins in resistance of acute myeloid leukaemia (AML) blasts to apoptosis. We found that the levels of both mRNA and proteins of APRIL, BAFF and their receptors were expressed in leukaemic cells of 24 newly diagnosed, untreated AML patients. We also demonstrated that patients who did not further respond to induction therapy (NR) presented with significantly higher baseline APRIL and BAFF expression on AML blasts as compared to these subjects who, after induction, achieved complete remission (CR) following induction therapy. Moreover, we observed striking differences in baseline levels of BCMA between CR and NR patients as we did not find detectable expression of this receptor in the latter group of patients. Interestingly, we found that AML blasts collected at baseline from NR patients cultured in presence of exogenous BAFF and APRIL were significantly more resistant to spontaneous or drug-induced apoptosis as compared with cells derived from CR patients. Altogether, our data confirm that BAFF and APRIL signaling play important role in AML pathogenesis and susceptibility to cytotoxic therapy while measuring of BCMA expression on AML cells can become a novel prognostic factor for chemotherapy response.

Lactic acid bacteria strains exert immunostimulatory effect on H. pylori-induced dendritic cells.

The aim of this study was to find out if selected lactic acid bacteria (LAB) strains (antagonistic or nonantagonistic against H. pylori in vitro) would differ in their abilities to modulate the DCs maturation profiles reflected by their phenotype and cytokine expression patterns. Methods. Monocyte-derived DCs maturation was elicited by their direct exposure to the LAB strains of L. rhamnosus 900 or L. paracasei 915 (antagonistic and nonantagonistic to H. pylori, resp.), in the presence or absence of H. pylori strain cagA+. The DCs maturation profile was assessed on the basis of surface markers expression and cytokines production. Results. We observed that the LAB strains and the mixtures of LAB with H. pylori are able to induce mature DCs. At the same time, the L. paracasei 915 leads to high IL-10/IL-12p70 cytokine ratio, in contrast to L. rhamnosus 900. Conclusions. This study showed that the analyzed lactobacilli strains are more potent stimulators of DC maturation than H. pylori. Interestingly from the two chosen LAB strains the antagonistic to H. pylori-L. rhamnosus strain 900 has more proinflammatory and probably antibactericidal properties.