Hydroxyurea Induces Bone Marrow Mesenchymal Stromal Cells Senescence and Modifies Cell Functionality In Vitro

Hydroxyurea (HU) is an antineoplastic agent that functions as an antimetabolite compound by inhibiting the ribonucleotide reductase. HU acts mainly as a cytostatic drug that through DNA replication stress may trigger a premature senescence-like cell phenotype, though its influence on bone marrow-derived mesenchymal stem/stromal cell (BMMSC) functions has not elucidated yet. Our results indicate that HU inhibits the growth of human BMMSC alongside senescence-like changes in both morphology and replicative potential, provokes cell cycle arrest at the S phase without affecting cellular viability and induces the expression of senescence-associated β-galactosidase and p16INK4. Moreover, HU-induced senescent BMMSC, although they did not change MSC markers expression, exhibited reduced capacity osteogenic and adipogenic differentiation. Conversely, HU treatment increased immunoregulatory functions of BMMSC compared with untreated cells and determined by T-cell proliferation. Interestingly, HU did not influence the capacity of BMMSC to induce monocytic myeloid-derived suppressor cells. Thus, these results suggest that HU improves the BMMSC functions on the T-cell inhibition and preserves their interaction with myeloid cell compartment. Mechanistically, BMMSC under HU treatment displayed a downregulation of mTOR and p38 MAPK signaling that may explain the reduced cell differentiation and increased immunomodulation activities. Together, the results obtained in this investigation suggest that HU by inducing senescence-like phenotype of BMMSC influences their cellular differentiation and immunoregulatory functions

Regulation of S100As Expression by Inflammatory Cytokines in Chronic Lymphocytic Leukemia

The calcium-binding proteins S100A4, S100A8, and S100A9 are upregulated in chronic lymphocytic leukemia (CLL), while the S100A9 promotes NF-κB activity during disease progression. The S100-protein family has been involved in several malignancies as mediators of inflammation and proliferation. The hypothesis of our study is that S100A proteins are mediators in signaling pathways associated with inflammation-induced proliferation, such as NF-κB, PI3K/AKT, and JAK/STAT. The mononuclear cells (MNCs) of CLL were treated with proinflammatory IL-6, anti-inflammatory IL-10 cytokines, inhibitors of JAK1/2, NF-κB, and PI3K signaling pathways, to evaluate S100A4, S100A8, S100A9, and S100A12 expression as well as NF-κB activation by qRT-PCR, immunocytochemistry, and immunoblotting. The quantity of S100A4, S100A8, and S100A9 positive cells (p < 0.05) and their protein expression (p < 0.01) were significantly decreased in MNCs of CLL patients compared to healthy controls. The S100A levels were generally increased in CD19+ cells compared to MNCs of CLL. The S100A4 gene expression was significantly stimulated (p < 0.05) by the inhibition of the PI3K/AKT signaling pathway in MNCs. IL-6 stimulated S100A4 and S100A8 protein expression, prevented by the NF-κB and JAK1/2 inhibitors. In contrast, IL-10 reduced S100A8, S100A9, and S100A12 protein expressions in MNCs of CLL. Moreover, IL-10 inhibited activation of NF-κB signaling (4-fold, p < 0.05). In conclusion, inflammation stimulated the S100A protein expression mediated via the proliferation-related signaling and balanced by the cytokines in CLL

Is There a Possibility to Involve the Hormesis Effect on the Soybean with Glyphosate Sub-Lethal Amounts Used to Control Weed Species Amaranthus retroflexus L.?

Sub-lethal doses of herbicides can promote plant growth and have a positive effect on an organism this is called hormesis. The purpose of this study was to test the effects of sub-lethal doses of glyphosate on soybean (Glycine max(L.) Merr.) (1.8, 3.6, 7.2, 36, 180, and 720 g ha(-1)) and Amaranthus retroflexus L. (7.2, 36, 180, 720, 1440, and 2880 g ha(-1)). Different biological parameters, such as phytotoxicity, fresh weight, root length, content of photosynthetic pigments, and shikimate concentration, were measured. Glyphosate in doses of 1440 and 2880 g ha(-1) destroyed A. retroflexus plants. A fresh weight of A. retroflexus at a dose of 36 g ha(-1) was reduced by 76.31%, while for the soybean it was reduced by 19.26%. At the highest dose, the shikimate concentration was 145% in the soybean, while in A. retroflexus, the concentration increased by 58.80% compared to the control plants. All doses of glyphosate were statistically significantly different in terms of chlorophyll a content, while higher doses in A. retroflexus caused chlorophyll b to decrease. The change in the production of carotenoids was not statistically significant. The results showed that sub-lethal amounts of glyphosate did not lead to stimulation of measured parameters of soybean

Inflammation Promotes Oxidative and Nitrosative Stress in Chronic Myelogenous Leukemia

Chronic inflammation is characterized by the production of reactive oxygen species (ROS), reactive nitrogen species, and inflammatory cytokines in myeloproliferative neoplasms (MPNs). In addition to these parameters, the aim of this study was to analyze the influence of ROS on the pro-liferation-related AKT/mTOR signaling pathway and the relationship with inflammatory factors in chronic myelogenous leukemia (CML). The activity of the antioxidant enzymes superoxide dis-mutase, glutathione peroxidase, and catalase is reduced in erythrocytes while levels of the oxidative stress markers malondialdehyde and protein carbonyl are elevated in the plasma of patients with CML. In addition, nitrogen species (nitrotyrosine, iNOS, eNOS) and inflammation markers (IL-6, NFkB, and S100 protein) were increased in granulocytes of CML while anti-inflammatory levels of IL-10 were decreased in plasma. CML granulocytes exhibited greater resistance to cytotoxic H2O2 activity compared to healthy subjects. Moreover, phosphorylation of the apoptotic p53 protein was reduced while the activity of the AKT/mTOR signaling pathway was increased, which was further enhanced by oxidative stress (H2O2) in granulocytes and erythroleukemic K562 cells. IL-6 caused oxidative stress and DNA damage that was mitigated using antioxidant or inhibition of inflammatory NFkB transcription factor in K562 cells. We demonstrated the presence of oxidative and ni-trosative stress in CML, with the former mediated by AKT/mTOR signaling and stimulated by in-flammation

Inhibition of proinflammatory signaling impairs fibrosis of bone marrow mesenchymal stromal cells in myeloproliferative neoplasms

Although bone marrow-derived mesenchymal stromal cells (BM-MSCs) have been identified as a major cellular source of fibrosis, the exact molecular mechanism and signaling pathways involved have not been identified thus far. Here, we show that BM-MSCs contribute to fibrosis in myeloproliferative neoplasms (MPNs) by differentiating into αSMA-positive myofibroblasts. These cells display a dysregulated extracellular matrix with increased FN1 production and secretion of profibrotic MMP9 compared to healthy donor cells. Fibrogenic TGFβ and inflammatory JAK2/STAT3 and NFκB signaling pathway activity is increased in BM-MSCs of MPN patients. Moreover, coculture with mononuclear cells from MPN patients was sufficient to induce fibrosis in healthy BM-MSCs. Inhibition of JAK1/2, SMAD3 or NFκB significantly reduced the fibrotic phenotype of MPN BM-MSCs and was able to prevent the development of fibrosis induced by coculture of healthy BM-MSCs and MPN mononuclear cells with overly active JAK/STAT signaling, underlining their involvement in fibrosis. Combined treatment with JAK1/2 and SMAD3 inhibitors showed synergistic and the most favorable effects on αSMA and FN1 expression in BM-MSCs. These results support the combined inhibition of TGFβ and inflammatory signaling to extenuate fibrosis in MPN

Molecural mechanism of chemotherapeutic hydroxyurea is mediated by NOS2

Background:: Hydroxyurea (HU) is a chemotherapeutic agent that reduces ribonucleotide reductase, stops DNA synthesis and repar, and therefore causes cell proliferation inhibition and apoptosis. Due to its cytostatic properties, HU is frequently used for treatment of myeloproliferative neoplasms, ovarian cancer, and sickle cell anemia. Nitric oxide (NO), produced by nitric oxide synthase (NOS) enzymes is a potent signaling molecule involved in blood flow regulation, neutrotransmission, and immunity. Although HU treatment increases NO levels, up to date it is not clear whether it originates from activation of NOS enzymes or HU degradation. Aims: The aim of this study was to determine the involvement of NOS2 enzyme in the cytostatic effect of HU. Methods: To examine the involvement of the NOS2 enzyme in the molecular mechanism of HU, we treated erythroleukemic HEL92.7.1 cells with pan-selective NOS inhibitor L-NAME (200µM, 1mM, and 5mM), NOS2 specific inhibitor 1400W (1, 10, and 100µM), or NOS2/NOS3 inhibitor DPI (1, 5, and 10µM), in combination with hydroxyurea (200µM), and monitored their effect on proliferation and cell cycle. Immunocytochemistry for the proliferation marker Ki67 was performed to assess proliferation, while cell distribution in cell cycle phases was determined by flow cytometry after propidium iodide staining. Colony forming assay have been performed with the bone marrow cells of Nos2 null mice after oral HU treatment to corroborate the data obtained by enzymatic inhibition. Results: In this study, we demonstrated that treatment of HEL92.7.1 cells with HU induces a dose-dependent increase in NOS2 protein levels and two products of the enzyme NOS - NO and citrulline. HU-induced citrulline levels can be reduced by treatment with the NOS inhibitor L-NAME, indicating that NO is produced de novo by the NOS enzyme rather than HU degradation. Inhibition of the NOS2 enzyme by L-NAME, 1400W, or DPI was sufficient to abolish HU-mediated inhibition of proliferation. While HU increased the number of cells in S-phase of the cycle at the expanse of the G0/G1 due to blocked DNA synthesis, combined treatment with HU and L-NAME or DPI inhibitor resulted in decreased G0/G1 phase and increased S and G2/M phases pointing to increased proliferation. These data indicate that the cytostatic properties of HU are mediated by the NOS2 enzyme. A colony formation assay showed that Nos2 deficient bone marrow cells isolated from mice treated orally with HU (200mg/kg) formed significantly more erythroid colonies (BFU-E and CFU-E) and granulocyte/macrophage progenitors (CFU-GM) compared to HU treated wild-type and untreated Nos2 null mice showing the involvement of Nos2 in the molecular mechanism of HU in vivo. Summary/Conclusion: Our results show that HU induces the enzymatic activity of the NOS2 protein which in turn is involved in the HU regulation of proliferation and cell cycle. Comprehensive knowledge of the molecular mechanism of HU might help to improve its beneficial properties and decrease adverse effects

Inflammation mediated thrombus formation in lymphomas

Background: Patients with lymphomas increased the risk of thrombotic complications, especially in diagnosis and during chemotherapy treatment, in the range of 2.9-4.2%. Aims: Our hypothesis is that inflammation and provoked immunity are responsible for generation of thrombus due to disturbed balance between coagulation and fibrinolysis. Methods: Quantification of neutrophil extracellular traps (NETs) from peripheral blood of 80 patients with Hodgkin lymphoma (HL), diffuse large B-cell lymphoma (DLBCL), and follicular lymphoma (FL) measuring circulating cell-free DNA (cfDNA) and myeloperoxidase (MPO) activity. The inflammatory cytokines, coagulation factors and chemokines are measured by enzyme-linked immunosorbent assay (ELISA) and flow cytometry in peripheral blood, while fibrinolytic activity by fluorescent tissue-type plasminogen activator (tPA) and urokinase plasminogen activator (uPA) assays. Using a Boyden chamber, trans-endothelial migration of mononuclear cells (MNC) across a monolayer of human microvascular endothelial cells (HMEC-1) will be observed. Results: The pro-inflammatory cytokines IL-1β and TNF-α were significantly increased in DLBCL and HL, but not the chemokines IL-8 and MCP-1. NETs were increased in the peripheral blood of patients with HL (p<0.05) as measured by cfDNA and MPO activity. In contrast, cfDNA was largely reduced in DLBCL with thrombosis (p<0.001). Trans-endothelial migration of MNC was decreased by IL-6, but increased by TNF-α (p<0.001) in DLBCL with thrombosis. In the absence of thrombosis, MNC of HL demonstrated increased trans-endothelial migration in the presence of pro-inflammatory IL-6 (p<0.01), while MNC of HL and DLBCL in the presence of TNF-α (p<0.05). Regarding coagulation, factor VIII was increased in HL (p<0.05), while tissue factor in non-Hodgkin lymphomas (DLBCL and FL, p<0.05). Adhesion molecule P-selectin was increased in lymphomas, mostly in non-Hodgkin lymphomas (p<0.0001), while TGF-β is only in FL (p<0.001). Fibrinogen was negatively correlated with cfDNA (p=0.021, r=-0.767) in HL, while in positive correlation with TNF-α (p=0.028, r=0.517), IL-8 (p=0.009, r=0.598) and MCP-1 (p=0.004, r=0.643) in FL and with TGF-β (p=0.007, r=0.748) in HL. In opposite to uPA, fibrinolytic activity was decreased in the plasma of patients with HL, DLBCL, and FL (p<0.05) as measured by tPA. The tPA was in negative correlation with MPO in HL (p=0.017, r=-0.783) and FL (p=0.006, r=-0.818), while positively correlated with cfDNA in DLBCL (p=0.034, r=0.402, Table 1). The uPA was in positive correlation with cfDNA (p=0.009, r=0.692) and fibrinogen (p=0.009, r=0.692) in FL. Tissue factor (CD142+) procoagulant microparticles derived from monocytes (CD14+: 7.49±0.2, p<0.001) and activated monocytes (CD14+/CD16+: 3.75±0.8%, p<0.05) were increased in DLBCL compared to healthy controls. Summary/Conclusion: Chronic inflammation is present in the examined lymphomas where TNF-α, as an activator of the immune response, is linked with the initiation of thrombus formation. Moreover, augmented innate immunity is accompanied by procoagulants that mutually support thrombosis. F

PB1832: Inflammation induced coagulation in acute myeloid leukemia

Background: Patients with acute myeloid leukemia (AML) have an increased risk of thrombotic complications in the range of 4.2 - 5.2%. Aims: Our hypothesis is that inflammation is responsible for deterioration of coagulation in AML. Methods: Quantification of neutrophil extracellular traps (NETs) from peripheral blood of patients with AML by measurement of circulating cell-free DNA (cfDNA) and myeloperoxidase (MPO) activity. Inflammatory cytokines, coagulation factors and chemokines are measured by enzyme-linked immunosorbent assay (ELISA) and flow cytometry in peripheral blood, while fibrinolytic activity with fluorescent tissue-type plasminogen activator (tPA) and urokinase plasminogen activator (uPA) assays. Results: The pro-inflammatory cytokines IL-1β and TNF-α were significantly increased in AML, but not the chemokines IL-8 and MCP-1. NETs were increased in the peripheral blood of patients with AML (p<0.05) as measured by cfDNA and MPO activity. Regarding coagulation, factor VIII (p<0.05) and adhesion molecule P-selectin (p<0.001) were increased in plasma. Fibrinolytic activity was 3-fold decreased in the plasma of patients with AML (p<0.01) as measured by tPA. In contrast, uPA levels were increased in patients with AML (p<0.05). Tissue factor (CD142+) inflammatory microparticles derived from monocytes (CD14+: 5.1±0.6, p<0.001), activated monocytes (CD14+/CD16+: 2.89±0.4%, p<0.05) and circulating endothelial cells (CD31+/CD144+: 4.08±0.5%, p<0.05) were increased in AML compared to healthy controls. Summary/Conclusion: Chronic inflammation is present in AML in parallel with reduced fibrinolysis and increased coagulation provoking the risk of thrombosis. A panel of the applied inflammatory/ procoagulant biomarkers can be used as a predictor of thrombosis in AML

THE USE OF INTEGRATIVE MULTI-OMICS APPROACH IN CULTIVATION AND CHARACTERIZATION OF GUT BACTERIA RELATED TO MICROBIOTA-GUT-BRAIN AXIS AS A SOURCE FOR NEXT GENERATION PROBIOTICS

There has been an epidemic of various non-communicable degenerative and autoimmune diseases, strongly associated with the modern lifestyle. Among them, neurodegenerative and psychiatric disorders represent a huge burden on society. Recently, all these diseases have been associated with the gut microbiota dysbiosis. Gut microbiota-host interaction research has been greatly improved due to development of molecular high-throughput techniques based on various ‘omics’ techniques coupled with bioinformatics and data science developments. However, the mechanisms of the host–microbiota crosstalk are still poorly understood. The NextGenBiotics project proposes an innovative integrative multi-omics research strategy for deciphering the mechanism behind the cross-talk among microbiota and gut-brain-axis. The 118 novel NGPs candidates belonging to Dorea sp., Blautia sp., Bacteroides sp., Roseburia sp., Sellimonas sp., Faecalicatena sp., Phascolarctobacterium faecium, and Faecalimonas sp. were cultivated. The 25 NGPs with confirmed safe status and potential probiotic potential were screened in C. elegans model for their effects on behavioural and neuronal activity. The most prominent candidates with ability to upregulate expression of genes involved in neurotransmiting are further tested in EAE (an animal model for MS) and CUMS depression model. The specific microbiota-derived metabolites have been identified as potential neuro- and psycho-biotics. The NextGenBiotics is highly ambitious project, dedicated to pioneering work in the field of multi-omics studies related to the cultivation of novel anaerobic NGPs and the studying of their effect on MGBA. This concept enabled studying bidirectional communication between gut microbiota and brain on the functional level that will significantly contribute to the growing body data related to MGBA. The results obtained during NextGenBiotics determined the genes/metabolites and the associated mechanisms involved in health-promoting effects of NGPs in MGBA beyond stateof- the-art, broadening the scientific knowledge and opening up the possible novel therapeutic approaches in prevention and therapy of neurodegenerative and psychiatric diseases.Book of abstract: From biotechnology to human and planetary health XIII congress of microbiologists of Serbia with international participation Mikromed regio 5, ums series 24: 4th – 6th april 2024, Mona Plaza hotel, Belgrade, Serbi

Sex Differences and Cytokine Profiles among Patients Hospitalized for COVID-19 and during Their Recovery: The Predominance of Adhesion Molecules in Females and Oxidative Stress in Males

The severity and mortality of coronavirus disease 2019 (COVID-19) are greater in males than in females, though the infection rate is the same in the two sexes. We investigated sex hormone differences associated with the hyperinflammatory immune response to SARS-CoV-2 on the basis of patients’ cytokine profiles and vaccination statuses. Clinical and laboratory data of 117 patients with COVID-19 were collected to examine sex differences associated with oxidative stress markers, neutrophil extracellular traps (NETs), and plasma cytokine levels up to 5 months from hospital admission. The testosterone and free testosterone levels were low in male patients with COVID-19 and returned to normal values after recovery from the disease. The dihydrotestosterone (DHT) levels were transiently reduced, while the sex hormone-binding globulin levels were decreased in post-COVID-19 male patients. The levels of the inflammatory cytokines interleukin-6 (IL-6) and IL-10 appeared generally increased at diagnosis and decreased in post-COVID-19 patients. In females, the concentration of tumor necrosis factor-alpha was increased by four times at diagnosis. The levels of the coagulation markers intercellular adhesion molecule-1 (ICAM-1) and E-selectin were consistently upregulated in post-COVID-19 female patients, in contrast to those of vascular cell adhesion molecule-1 (VCAM-1), P-selectin, and chemokine IL-8. DHT increased the levels of reactive oxygen species in the neutrophils of male patients, while estradiol decreased them in females. Markers for NET, such as circulating DNA and myeloperoxidase, were significantly more abundant in the patients’ plasma. Sex hormones have a potential protective role during SARS-CoV-2 infection, which is weakened by impaired testosterone synthesis in men