E2f2 Attenuates Apoptosis of Activated T Lymphocytes and Protects from Immune-Mediated Injury through Repression of Fas and FasL

Targeted disruption of E2f2 in mice causes T-cell hyperactivation and a disproportionate cell cycle entry upon stimulation. However, E2f2−/− mice do not develop a lymphoproliferative condition. We report that E2f2 plays a Fas-dependent anti-apoptotic function in vitro and in vivo. TCR-stimulated murine E2f2−/− T cells overexpress the proapoptotic genes Fas and FasL and exhibit enhanced apoptosis, which is prevented by treatment with neutralizing anti-FasL antibodies. p53 pathway is activated in TCR-stimulated E2f2−/− lymphocytes, but targeted disruption of p53 in E2f2−/− mice does not abrogate Fas/FasL expression or apoptosis, implying a p53-independent apoptotic mechanism. We show that E2f2 is recruited to Fas and FasL gene promoters to repress their expression. in vivo, E2f2−/− mice are prone to develop immune-mediated liver injury owing to an aberrant lymphoid Fas/FasL activation. Taken together, our results suggest that E2f2-dependent inhibition of Fas/FasL pathway may play a direct role in limiting the development of immune-mediated pathologies.

Immunomodulatory Effect of Human Umbilical Cord Blood-derived Mesenchymal Stem Cells on Activated T-lymphocyte

Many studies have been performed about regenerative and immunomodulatory properties of mesenchymal stem cells (MSCs) and their application in different treatment approaches. The present study aimed to investigate the immunomodulatory effect of umbilical cord blood-derived mesenchymal stem cells (UCB-MSCs) on the gene expression profile of cytokines in stimulated T-lymphocytes. For this purpose, MSCs were isolated from umbilical cord blood samples and cultured in Dulbecco's Modified Eagle Medium supplemented with 10% fetal bovine serum. The nature of MSCs was identified by flow cytometry analysis and differentiation to the adipocyte and osteocyte lineage. Moreover, to investigate the immunomodulatory effects of MSCs on T cells, a co-culture system was designed and expression levels of interleukin (IL)-2, IL-4, IL-6, IL-10, IL-13, interferon-gamma (IFN-γ), tumor necrosis factor-alpha (TNF-α), and transforming growth factor-beta (TGF-β) genes were measured; using the real-time polymerase chain reaction (RT-PCR) technique. Our results demonstrated the ability of MSCs to differentiate into adipocyte and osteocyte lineages. Further investigation also displayed that although UCB-MSCs could significantly reduce the expression of pro-inflammatory cytokines like IL-2, IL-6, IFN-γ, and TNF-α in activated T-lymphocytes, they noticeably potentiated the expression levels of IL-4, IL-10, IL-13, and TGF-β in the co-culture setting. In conclusion, UCB-MSCs have immunomodulatory effects on activated T-lymphocytes in favor of anti-inflammatory responses.

Immune response in new coronavirus infection COVID-19 in children and adults

Introduction. It is known that COVID-19 occurs more often in adult patients, especially if they have concomitant somatic diseases, children are at less risk of developing it. The aim of this work is to evaluate and compare immune response parameters in new coronavirus infection COVID-19 in children and adults. Materials and methods. The results of the examination of 56 adults 19-55 years old and 57 children 14-18 years old were included in the work. The examination results of COVID-19 patients were compared with similar data in practically healthy individuals of the corresponding age groups. All patients underwent laboratory tests to determine the following parameters: presence of SARS-CoV-2 RNA, general blood test parameters, major lymphocyte subpopulations, level of total immunoglobulins (IgM, IgG, IgA), number of CIC, absorbance and bactericidal activity of leukocytes.Results. The proportion of positive findings for SARS-CoV-2 RNA in different age groups ranged from 13.6% to 25.8%. General and specific patterns of immune response in patients of different age groups were established. Common features were an increase in the number of circulating immune complexes and activated T-lymphocytes. Differences were noted in the level of serum immunoglobulins IgM and IgG, neutrophil uptake activity, the number of monocytes, as well as in the level of different subpopulations of lymphocytes. Discussion. In adults, changes in the adaptive immune response, including the cellular level, are predominantly expressed. In children, there are signs of inefficiency of innate mechanisms of immune responses. Conclusion. The dynamics of the number of examined and positive findings correlate with similar figures in Russia and have a two-wave pattern. Increased number of circulating immune complexes and activated T-lymphocytes is typical for all patients with new coronavirus infection COVID-19 regardless of age, which is a sign of acute infection-inflammatory process development and insufficiently effective elimination of antigen (pathogen).

Immunological and genetic indices in workers under long-term exposure to low-doses of acrylonitrile

Introduction. Nowadays there is very relevant research on the study of the characteristics of the impact on the health of workers of low levels of harmful factors (acrylonitrile) of production during long-term exposure. Aim of the study was to examine peculiarities of immunologic and genetic indices in workers under the long-term exposure to acrylonitrile in low doses. Materials and methods. Our research object was working area air (MPCw.ar.=0.5 mg/m3) and biological media (blood and exhaled air) of workers employed at industrial rubber manufacture. Acrylonitrile was determined via a non-invasive procedure in exhaled air with samples being concentrated on sorption tubes that were then analyzed with capillary gas chromatography. Blood samples were examined to determine contents of malonic dialdehyde, lymphocytes (absolute and relative activated T-lymphocytes CD3+CD25+, absolute and relative activated T-lymphocytes CD3+CD95+), cytokines (VEGF), oncomarkers (PSA), and adrenals hormones; to do that, we applied ELISA tests and flow cytometry. Results. Acrylonitrile was established to occur in working area air in concentrations varying within MPCw.ar. range (0.007-0.015 mg/m3) being 2-3 times higher than in air inside offices at the same enterprise. We obtained statistically significant linear dependence between concentrations of acrylonitrile in the air exhaled by workers (y) and their working experience (x) that was given with the following equation: y=0.00046+0.00027x. According to the results of the laboratory examination of the workers, violations of the antioxidant defense were established. Contents of malonic dialdehyde and steroid hormones including progesterone, estradiol, and hydrocortisone that were pathogenetically linked to each other were authentically up to 3.2 times higher in the test group than in the reference one (p<0.05). Risk for antioxidant protection disorders such as elevated malonic dialdehyde contents in blood plasma might occur in the test group was 1.58 times higher than in the reference one. Conclusion. We revealed certain peculiarities in polymorphism of PPARGC1A Gly482Ser rs8192678 gene, the variability of which contributes to the formation of pathology of the cardiovascular, endocrine systems, oncoproliferative states that increase the likelihood of these undesirable events.

Role of the PD‐1/PD‐L1 Signaling in Multiple Sclerosis and Experimental Autoimmune Encephalomyelitis: Recent Insights and Future Directions

Multiple sclerosis (MS) is an autoimmunity-related chronic demyelination disease of the central nervous system (CNS), causing young disability. Currently, highly specific immunotherapies for MS are still lacking. Programmed cell death 1 (PD-1) is an immunosuppressive co-stimulatory molecule, which is expressed on activated T lymphocytes, B lymphocytes, natural killer cells, and other immune cells. PD-L1, the ligand of PD-1, is expressed on T lymphocytes, B lymphocytes, dendritic cells, and macrophages. PD-1/PD-L1 delivers negative regulatory signals to immune cells, maintaining immune tolerance and inhibiting autoimmunity. This review comprehensively summarizes current insights into the role of PD-1/PD-L1 signaling in MS and its animal model experimental autoimmune encephalomyelitis (EAE). The potentiality of PD-1/PD-L1 as biomarkers or therapeutic targets for MS will also be discussed.

Ikzf2 Regulates the Development of ICOS+ Th Cells to Mediate Immune Response in the Spleen of S. japonicum-Infected C57BL/6 Mice

BackgroundTh cells (helper T cells) have multiple functions in Schistosoma japonicum (S. japonicum) infection. Inducible co-stimulator (ICOS) is induced and expressed in activated T lymphocytes, which enhances the development of B cells and antibody production through the ICOS/ICOSL pathway. It remains unclear about the role and possible regulating mechanism of ICOS+ Th cells in the spleen of S. japonicum-infected C57BL/6 mice.MethodsC57BL/6 mice were infected with cercariae of S. japonicum through the abdomen. The expression of ICOS, activation markers, and the cytokine production on CD4+ ICOS+ Th cells were detected by flow cytometry (FCM) and quantitative real-time PCR (qRT-PCR). Moreover, the differentially expressed gene data of ICOS+ and ICOS− Th cells from the spleen of infected mice were obtained by mRNA sequencing. Besides, Western blot and chromatin immunoprecipitation (ChIP) were used to explore the role of Ikzf2 on ICOS expression.ResultsAfter S. japonicum infection, the expression of ICOS molecules gradually increased in splenic lymphocytes, especially in Th cells (P &lt; 0.01). Compared with ICOS− Th cells, more ICOS+ Th cells expressed CD69, CD25, CXCR5, and CD40L (P &lt; 0.05), while less of them expressed CD62L (P &lt; 0.05). Also, ICOS+ Th cells expressed more cytokines, such as IFN-γ, IL-4, IL-10, IL-2, and IL-21 (P &lt; 0.05). RNA sequencing results showed that many transcription factors were increased significantly in ICOS+ Th cells, especially Ikzf2 (P &lt; 0.05). And then, the expression of Ikzf2 was verified to be significantly increased and mainly located in the nuclear of ICOS+ Th cells. Finally, ChIP experiments and dual-luciferase reporter assay confirmed that Ikzf2 could directly bind to the ICOS promoter in Th cells.ConclusionIn this study, ICOS+ Th cells were found to play an important role in S. japonicum infection to induce immune response in the spleen of C57BL/6 mice. Additionally, Ikzf2 was found to be one important transcription factor that could regulate the expression of ICOS in the spleen of S. japonicum-infected C57BL/6 mice.

In Vitro Sensitivity to Venetoclax and Microenvironment Protection in Hairy Cell Leukemia

Current standard treatment of patients with hairy cell leukemia (HCL), a chronic B-cell neoplasia of low incidence that affects the elderly, is based on the administration of purine analogs such as cladribine. This chemotherapy approach shows satisfactory responses, but the disease relapses, often repeatedly. Venetoclax (ABT-199) is a Bcl-2 inhibitor currently approved for the treatment of chronic lymphocytic leukemia (CLL) and acute myeloid leukemia (AML) in adult patients ineligible for intensive chemotherapy. Given that HCL cells express Bcl-2, our aim was to evaluate venetoclax as a potential therapy for HCL. We found that clinically relevant concentrations of venetoclax (0.1 and 1 µM) induced primary HCL cell apoptosis in vitro as measured by flow cytometry using Annexin V staining. As microenvironment induces resistance to venetoclax in CLL, we also evaluated its effect in HCL by testing the following stimuli: activated T lymphocytes, stromal cells, TLR-9 agonist CpG, and TLR-2 agonist PAM3. We found decreased levels of venetoclax-induced cytotoxicity in HCL cells exposed for 48 h to any of these stimuli, suggesting that leukemic B cells from HCL patients are sensitive to venetoclax, but this sensitivity can be overcome by signals from the microenvironment. We propose that the combination of venetoclax with drugs that target the microenvironment might improve its efficacy in HCL.

Protective Response in Experimental Paracoccidioidomycosis Elicited by Extracellular Vesicles Containing Antigens of Paracoccidioides brasiliensis

Paracoccidioidomycosis (PCM) is a systemic disease caused by Paracoccidioides spp. PCM is endemic in Latin America and most cases are registered in Brazil. This mycosis affects mainly the lungs, but can also spread to other tissues and organs, including the liver. Several approaches have been investigated to improve treatment effectiveness and protection against the disease. Extracellular vesicles (EVs) are good antigen delivery vehicles. The present work aims to investigate the use of EVs derived from Paracoccidioides brasiliensis as an immunization tool in a murine model of PCM. For this, male C57BL/6 were immunized with two doses of EVs plus adjuvant and then infected with P. brasiliensis. EV immunization induced IgM and IgG in vivo and cytokine production by splenocytes ex vivo. Further, immunization with EVs had a positive effect on mice infected with P. brasiliensis, as it induced activated T lymphocytes and NKT cell mobilization to the infected lungs, improved production of proinflammatory cytokines and the histopathological profile, and reduced fungal burden. Therefore, the present study shows a new role for P. brasiliensis EVs in the presence of adjuvant as modulators of the host immune system, suggesting their utility as immunizing agents.

Epigenetic modulation of selected immune response genes and altered functions of T lymphocytes and macrophages collectively contribute to autoimmune diabetes protection

We have previously demonstrated that treatment of female NOD mice with the histone deacetylase inhibitor Trichostatin A (TSA) bestowed irreversible protection against diabetes. Herein we show that drug treatment diminished the infiltration of the pancreas with CD4+ and CD8+ T cells and Ly-6C+ monocytes. Significantly, TSA administration selectively repressed the expression of a set of genes exaggerated during diabetes and constitutively expressed primarily in the spleen and rarely in the pancreas. These genes encode lymphokines, macrophage-associated determinants, and transcription factors. Although the copy numbers of many histone deacetylases increased during diabetes in the spleen and pancreas, only those upregulated in the spleen were rendered sensitive to repression by TSA treatment. The T lymphocytes derived from drug-treated donors displayed diminished diabetogenic potential following transfer into immunodeficient NOD.scid mice. In the immunocompromised recipients, diabetes caused by the transfer of activated T lymphocytes from untreated diabetic mice was hampered by the co-transfer of highly purified splenic Ly-6C+ macrophages from drug-treated mice. However, the transfer of Ly-6C+ macrophages from drug-treated mice failed to block ongoing diabetes in wild-type NOD mice. These data demonstrate that the modified gene expression and functional alteration of T lymphocytes and macrophages collectively contribute to diabetes protection afforded by the histone modifier in female NOD mice.

MiRNA 126 as a New Predictor Biomarker in Venous Thromboembolism of Persistent Residual Vein Obstruction: A Review of the Literature Plus a Pilot Study

Venous thromboembolism (VTE) is the third most common cardiovascular disease. Interleukins (ILs) and micro-ribonucleic acids (miRNAs) have been proposed as molecules able to modulate endothelial inflammation and platelet hyperactivity. At present, no early biomarkers are available to predict the outcome of VTE. We investigated in a pilot study a selected number of miRNAs and ILs as prognostic VTE biomarkers and reviewed literature in this setting. Twenty-three patients (aged 18–65) with a new diagnosis of non-oncological VTE and free from chronic inflammatory diseases were enrolled. Twenty-three age- and sex-matched healthy blood donors were evaluated as control subjects. Serum miRNAs (MiRNA 126, 155, 17.92, 195), inflammatory cytokines (IL-6, tumor necrosis factor-α, IL-8), and lymphocyte subsets were evaluated in patients at enrolment (T0) and in controls. In VTE patients, clinical and instrumental follow-up were performed assessing residual vein obstruction, miRNA and ILs evaluation at 3 months' follow-up (T1). At T0, IL-8, activated T lymphocytes, Treg lymphocytes, and monocytes were higher in patients compared with healthy controls, as were miRNA 126 levels. Moreover, miRNA 126 and IL-6 were significantly increased at T0 compared with T1 evaluation in VTE patients. Higher levels of MiR126 at T0 correlated with a significant overall thrombotic residual at follow-up. In recent years an increasing number of studies (case–control studies, in vivo studies in animal models, in vitro studies) have suggested the potential role of miRNAs in modulating the cellular and biohumoral responses involved in VTE. In the frame of epidemiological evidence, this pilot study with a novel observational approach supports the notion that miRNA can be diagnostic biomarkers of VTE and first identifies miRNA 126 as a predictor of outcome, being associated with poor early recanalization.