Tritiated Thymidine Incorporation Research Articles

Induction of Chromosomal Aberrations after Exposure to the Auger Electron Emitter Iodine-125, the β--emitter Tritium and Cesium-137 γ rays.

High-LET-type cell survival curves have been observed in cells that were allowed to incorporate 125I-UdR into their DNA. Incorporation of tritiated thymidine into the DNA of cells has also been shown to result in an increase in relative biological effectiveness in cell survival experiments, but the increase is smaller than observed after incorporation of 125I-UdR. These findings are explained in the literature by the overall complexity of the induced DNA damage resulting from energies of the ejected electron(s) during the decay of 3H and 125I. Chromosomal aberrations (CA) are defined as morphological or structural changes of one or more chromosomes, and can be induced by ionizing radiation. Whether the number of CA is associated with the linear energy transfer (LET) of the radiation and/or the actual complexity of the induced DNA double-strand breaks (DSB) remains elusive. In this study, we investigated whether DNA lesions induced at different cell cycle stages and by different radiation types [Auger-electrons (125I), β- particles (3H), or γ radiation (137Cs)] have an impact on the number of CA induced after induction of the same number of DSB as determined by the γ-H2AX foci assay. Cells were synchronized and pulse-labeled in S phase with low activities of 125I-UdR or tritiated thymidine. For decay accumulation, cells were cryopreserved either after pulse-labeling in S phase or after progression to G2/M or G1 phase. Experiments with γ irradiation (137Cs) were performed with synchronized and cryopreserved cells in S, G2/M or G1 phase. After thawing, a CA assay was performed. All experiments were performed after a similar number of DSB were induced. CA induction after 125I-UdR was incorporated was 2.9-fold and 1.7-fold greater compared to exposure to γ radiation and radiation from incorporated tritiated thymidine, respectively, when measured in G2/M cells. In addition, measurement of CA in G2/M cells after incorporation of 125I-UdR was 2.5-fold greater when compared to cells in G1 phase. In contrast, no differences were observed between the three radiation qualities with respect to exposure after cryopreservation in S or G1 phase. The data indicate that the 3D organization of replicated DNA in G2/M cells seems to be more sensitive to induction of more complex DNA lesions compared to the DNA architecture in S or G1 cells. Whether this is due to the DNA organization itself or differences in DNA repair capability remains unclear.

Apolipoprotein A-I inhibited group II innate lymphoid cell response mediated by microRNA-155 in allergic rhinitis

BackgroundGroup 2 innate lymphoid cells (ILC2s) have been found to take part in type 2 inflammation by secreting Th2 cytokines. Apolipoprotein A-I (Apo-AI), a major structural and functional protein of high-density lipoproteins, plays anti-inflammatory effects on neutrophils, monocytes, macrophages and eosinophils. However, its effects on ILC2 are not well characterized. ObjectiveIn this study, we aimed to investigate to the effect of Apo-AI on the proliferation and function of ILC2 as well as possible mechanism. MethodsThe protein expression of Apo-AI and the percentage of ILC2 in peripheral blood between 20 AR and 20 controls were detected using enzyme-linked immunosorbnent assay (ELISA) and flow cytometry. The effect of Apo-AI and miR-155 on ILC2 proliferation and function were detected by tritiated thymidine incorporation and ELISA. Anima models were adopted to verify the effect of Apo-AI in vivo. ResultsElevated expression of Apo-AI was observed in AR patients. The Apo-AI promotes ABCA1 expression by ILC2, which can be inhibited by anti-Apo-AI. The Apo-AI decreased ILC2 proliferation and the mRNA levels of GATA3 and RORα from ILC2. The miR-155 over-expression promoted the up-regulation of GATA-3 and type II cytokines from ILC2, while the addition of Apo-AI or miR-155 inhibitor inhibited the expression of GATA-3 and type II cytokines by ILC2 significantly. Apo-AI-/- mice showed as enhanced allergen-induced airway inflammation. The miR-155 inhibitor can reverse the enhanced allergen-induced airway inflammation in Apo-AI-/- mice, while miR-155 mimics can reverse the decreased allergen-induced airway inflammation in Apo-AI treated mice. ConclusionApo-AI suppressed the proliferation and function of ILC2 through miR-155 in AR. Our data provided new insights into the mechanism of allergen-induced airway inflammation.

EPEN-08. COMBINED PDGFR INHIBITOR AXITINIB AND RETINOID TRETINOIN DECREASES PROLIFERATION AND HIGH-RISK NEOPLASTIC SUBPOPULATION PROPORTIONS PFA EPENDYMOMA

Abstract Ependymoma (EPN) is fatal in over 50% of children and has not seen any therapeutic improvements in over 30 years. Based on data from single-cell RNA sequencing (scRNAseq) and large-scale screening of FDA-approved oncology compounds in posterior fossa group A (PFA) EPN, we hypothesized that combination of PDGFR inhibitors and retinoids therapy will selectively deplete aggressive mesenchymal and undifferentiated EPN subpopulations resulting in therapeutic benefit. In vitro screening of a panel of three receptor PDGFR inhibitors (PDGFRIs) and nine retinoid analogues in high-risk chromosome 1q+/6q- PFA cell lines MAF-811 and MAF-928 was performed to identify those drugs with (i) anti-proliferative effect (tritiated thymidine incorporation and live-cell imaging), (ii) depletion of high-risk associated neoplastic subpopulations (qRT-PCR using subpopulation specific markers and scRNAseq), and (iii) synergistic effects. PDGFRIs axitinib and pazopanib and retinoids tazarotene, adapalene and tretinoin showed superior potency versus other analogues. qRT-PCR showed that tazarotene and axitinib demonstrated beneficial subpopulation perturbation. Combination of the top two PDGFRIs (axitinib and pazopanib) and retinoids (tazarotene and tretinoin) demonstrated that axitinib combined with tretinoin provided the strongest synergistic anti-proliferative effect and depletion of high-risk-associated undifferentiated subpopulations. More definitive scRNAseq subpopulation analysis revealed a reduction of mesenchymal cells in MAF-811 in response to combined axitinib/tretinoin treatments. In both MAF-811 and MAF-928 there was a net increase in the proportion of differentiated subpopulations, which are associated with a more favorable clinical outcome, in response to combined axitinib/tretinoin, collectively supporting our original hypothesis. These results demonstrate that combined RTKi axitinib and retinoid tretinoin treatment has a synergistic anti-proliferative effect and reduction of high-risk subpopulation proportions. The effect of combined axitinib and tretinoin on survival and subpopulation perturbation is now being explored in vivo.

Basigin is necessary for normal decidualization of human uterine stromal cells.

Does basigin (BSG) regulate human endometrial stromal cell (HESC) decidualization in vitro? BSG regulates HESCs proliferation and decidualization. Studies have shown that in the human endometrium, BSG expression is menstrual-cycle dependent and its expression was significantly lower in uterine endometrium during the luteal phase of women experiencing multiple implantation failures after IVF than in women with normal fertility. We utilized a telomerase-immortalized HESCs in an in vitro cell culture model system to investigate whether BSG regulates decidualization of stromal cells. Further, we used microarray analysis to identify changes in the gene expression profile of HESCs treated with BSG small interfering RNA (siRNA). All experiments were repeated at least three times. The effect of BSG knockdown (using siRNA) on HESC proliferation was determined by counting cell number and by tritiated thymidine incorporation assays. The effect of BSG on decidualization of HESCs was determined by RT-qPCR for the decidualization markers insulin-like growth factor-binding protein 1 (IGFBP1) and prolactin (PRL). Immunoblotting was used to determine the effect of BSG siRNA on the expression of MMP-2,3. Microarray analysis was used to identify BSG-regulated genes in HESCs at Day 6 of decidualization. Functional and pathway enrichment analyses were then carried out on the differentially expressed genes (DEGs). The STRING online database was used to analyze protein-protein interaction (PPI) between DEG-encoded proteins, and CytoScape software was used to visualize the interaction. MCODE and CytoHubba were used to construct functional modules and screen hub genes separately. Several BSG-regulated genes identified in the microarray analysis were confirmed by qPCR. Knockdown of BSG expression in cultured stromal cells by siRNA significantly (P < 0.05) inhibited HESC proliferation, disrupted cell decidualization and down-regulated MMP-2 and MMP-3 expression. Microarray analysis identified 721 genes that were down-regulated, and 484 genes up-regulated with P < 0.05 in BSG siRNA treated HESCs. GO term enrichment analysis showed that the DEGs were significantly enriched in cell communication, signaling transduction and regulation, response to stimulus, cell adhesion, anatomical structure morphogenesis, extracellular matrix organization, as well as other functional pathways. KEGG pathway analysis identified upregulated gene enriched in pathways such as the MAPK signaling pathway, colorectal cancer, melanoma and axon guidance. In contrast, downregulated genes were mainly enriched in pathways including ECM-receptor interaction, PI3K-Akt signaling pathway, pathways in cancer, antigen processing, type I diabetes mellitus and focal adhesion. The top 10 hub nodes were identified using 12 methods analyses. The hub genes that showed up in two methods were screened out. Among these genes, upregulated genes included EGFR, HSP90AA1, CCND1, PXN, PRKACB, MGAT4A, EVA1A, LGALS1, STC2, HSPA4; downregulated genes included WNT4/5, FOXO1, CDK1, PIK3R1, IGF1, JAK2, LAMB1, ITGAV, HGF, MXRA8, TMEM132A, UBE2C, QSOX1, ERBB2, GNB4, HSP90B1, LAMB2, LAMC1 and ITGA1. Hub genes and module genes involved in the top three modules of PPI analysis were analyzed through the string database. Analysis showed that hub and module genes were related mainly to the WNT signaling pathway, PI3K-AKT signaling pathway and pathways in cancer. The microarray data set generated in this study has been published online at databank.illinois.edu. Most of the findings were obtained using an in vitro cell culture system that may not necessarily reflect in vivo functions. Our results demonstrate that BSG plays a vital role in decidualization and that downregulation of BSG in the uterine endometrium may be associated with infertility in women. The identified hub genes and pathways increase our understanding of the genetic etiology and molecular mechanisms underlying the regulation of decidualization by BSG. This work was supported by the NIH U54 HD40093 (R.A.N.). The authors have no competing interests to declare.

Detection of rare autoreactive T cell subsets in patients with pemphigus vulgaris.

Analysis of T lymphocyte proliferation and activation after antigenic or mitogenic stimulation is a vital parameter used in the diagnosis of various immuno-deficiencies and during the monitoring of treatment responses. Most applied techniques are based on the incorporation of tritiated thymidine (3H-TdR) or ELISPOT analysis, both rely on rather time-consuming/-intensive ex vivo protocols or encompass inherent drawbacks such as the inability to distinguish specific cell populations (3H-TdR, ELISPOT) or focus on a single cytokine (ELISPOT). Here we aimed at characterizing the rapid expression of intracellular CD154 (CD40L) as a marker for rare antigen-specific CD4+ T cells in pemphigus vulgaris (PV). Upon stimulation with human desmoglein (Dsg) 3, the major autoantigen in PV, the expression of CD154 was significantly increased in PV patients compared to healthy controls (HC) and correlated with anti-Dsg3 IgG titers. Patients with active disease showed higher numbers of Dsg3-reactive CD4+ T cells in CXCR5+ T follicular helper cells. In remittent PV and HC, CXCR5+CD4+ T cells remained largely unaffected by Dsg3. IL-17 and IL-21 expression were significantly induced only in CD154+CD4+ T cells from PV patients, lending themselves as potential novel treatment targets. Additionally, stimulation with immunodominant Dsg3-derived epitopes strongly induced a CD4+ T cell response via CD40-CD154 interaction similar to the human Dsg3 protein. We here established a rapid ex vivo assay allowing the detection of Dsg3-reactive CD4+ T cells from activated systemically available PBMCs, which further supports the crucial concept of antigen-specific T cells in the pathogenesis of PV.

P1308: SELECTIVE SMALL MOLECULE INHIBITION OF CTP SYNTHASE 1 (CTPS1) SUPPRESSES T CELL PROLIFERATION AND CYTOKINE RELEASE, HIGHLIGHTING A NOVEL THERAPEUTIC TARGET FOR GRAFT-VERSUS-HOST DISEASE

Background: Graft-versus-host disease (GvHD) significantly increases both the morbidity/mortality and economic cost of allogeneic haematopoietic stem cell transplantation. Key to successful therapy is effective disease control whilst maintaining a competent anti-infection response. Acute GvHD (aGvHD) is driven by the rapid proliferation of, and cytokine release from, donor-derived T cells. Standard of care therapy with systemic steroids is associated with broad and deleterious immunosuppression, and fails to achieve adequate disease control in a third of patients. There is currently a lack of consensus around therapy beyond steroids [1]. CTP synthases catalyse the conversion of UTP to CTP, the rate limiting step in pyrimidine synthesis. Humans have two isoforms of this enzyme (CTPS1 and CTPS2); human genetic studies have identified an essential and non-redundant role for CTPS1 in the proliferation of B and T cells [2]. [1] Blood. 2020 May 7;135(19):1630-1638. [2] Nature. 2014 Jun 12;510(7504):288-92. [3] J Transl Med. 2010 Oct 26;8:104. Aims: To assess the impact of selective CTPS1 inhibition on the proliferation of, and cytokine release from, human T cells. Methods: Aliquots of whole blood or isolated peripheral blood mononuclear cells (PBMC) from healthy volunteer donors underwent T cell activation with CD3/CD28 beads and incubation with or without a selective CTPS1 inhibitor for 24-72 hours. Levels of intracellular CTP, ATP and GTP nucleotides were quantitated by liquid chromatography–mass spectrometry; cell proliferation was assessed by tritiated thymidine incorporation, Ki-67 by flow cytometry and cytokine release by analysis of plasma using the Luminex platform. Results: STP938 is a potent and reversible low molecular weight small molecule inhibitor of CTPS1, which shows >1,300-fold selectivity for human CTPS1 over CTPS2. Exposure of stimulated PBMCs to STP938 resulted in a concentration dependent depletion of CTP but had no effect on the levels of GTP or ATP, confirming selective inhibition of CTP synthase by STP938. CTPS1 inhibition by STP938 elicited a concentration dependent inhibition of CD3/CD28-induced T cell proliferation in whole blood samples after 72 hours incubation, resulting in full suppression of proliferation at the highest concentration tested (1 µM) (Figure A). Exposure to STP938 also reduced the proportion of T cells in cell cycle, as evidenced by a decrease in the expression of Ki-67 (Figure B). STP938 exposure induced a concentration dependent inhibition of T cell cytokine release in whole blood samples, with higher STP938 concentrations producing near-complete suppression (Figure C). Notably, significant inhibition of T cell cytokine release was observed after only 24 hours’ exposure of stimulated T cells to STP938 (Figure D, 1 μM STP938). Given that human T cells do not undergo cell division until at least 40 hours after CD3/CD28 stimulation is initiated [3], these findings indicate that the ability of CTPS1 inhibition to prevent cytokine release is independent of its effects on cell proliferation. Image:Summary/Conclusion: CTPS1 inhibition by STP938 induces a rapid suppression of T cell cytokine release along with suppression of T cell proliferation; both of these effects are concentration dependent and near maximal at exposures of STP938 that are likely to be achievable in the clinic. CTPS1 represents a novel target with the potential to effect rapid and specific disease control in aGvHD. STP938 is currently on the path to clinical development in lymphoid malignancy.

Effects of Dexamethasone on DNA Synthesis in Lens Epithelial Cells Are Dependent on Cell Type and Growth Factor

Purpose To determine the factors that influence the ability of dexamethasone (dex) to inhibit or stimulate the growth of lens epithelial cells. Method Different growth factors with or without dex (10−6 M) were added to quiescent cultures of two clones of Nakano mouse lens epithelial cells (NK11) in serum-free medium. DNA synthesis was then measured after 8–12 hours by the incorporation of tritiated thymidine. Results Dex was found to both stimulate and inhibit mitogen-induced 3H-thymidine incorporation into the DNA of cultured mouse lens epithelial cells. Enhancement or repression by dex was found to depend on the growth factor used to stimulate the quiescent cell. EGF and insulin were consistently inhibited with dex. Basic fibroblast growth factor (bFGF) and retinoblastoma-derived growth factor (RbDGF) were both enhanced and inhibited by dex, depending on the growth factor concentration and the cell clone used for the experiment. Additionally, RbDGF protects against the dex inhibition of insulin stimulation, but not the inhibition of EGF stimulation. Progesterone, an inhibitor of the activation of the glucocorticoid receptor, blocks the dex inhibitory effect on the EGF and insulin stimulation of DNA synthesis. The ability of progesterone to affect the dex inhibition is consistent with the dex receptor modulating DNA synthesis. The dex effect on DNA synthesis, either stimulatory or inhibitory, was still seen if dex was added as late as 10 hours after the growth factor. Conclusions The study demonstrated that dex reduces the overall growth and activity of lens epithelial cells in vitro. This result provides insight into the risk of developing posterior subcapsular cataracts (PSC) in patients on oral glucocorticoid therapy. Understanding the basic mechanisms by which steroids mediate lens cell growth may provide the ability to more accurately predict who will develop PSC. The present studies show the difference in the effect of dex from lens cell to lens cell, but, more importantly, suggest a pattern of dependent variables that might prove useful in such predictions.

026 Detection of rare autoreactive T cell subsets in patients with pemphigus vulgaris by the CD154 activation assay

Analysis of T cell proliferative responses to antigenic or mitogenic stimuli are based on e.g. the incorporation of tritiated thymidine or BrdU, CFSE labeling and the detection of secreted cytokines by ELISA or ELISPOT assay. There are inherent drawbacks of these methods rather long ex vivo expansion, stimulation protocols or the inability to distinguish specific cell populations and the assumption of importance of certain cytokines. Rapid identification and quantification of low- frequent autoreactive T cells, however, presents a main goal in autoimmune diseases such as pemphigus vulgaris (PV).

The Effect of IL-18 on Group 2 Innate Lymphoid Cells in Allergic Rhinitis

Group 2 innate lymphoid cells (ILC2s) promote allergic inflammation by producing interleukin-4 (IL-4), IL-5, IL-9, and IL-13. IL-18 can promote T helper 2 cell (Th2) response by inducing IL-4, and IL-13 production from mast cells and basophils. However, the regulation of IL-18 on ILC2s remained unknown. To investigate the regulatory role of IL-18 in inducing the type 2 innate lymphoid cells. Twenty patients with allergic rhinitis (AR) and 20 controls were enrolled. The mRNA and protein levels of IL-18 in serum, as well as the frequencies of ILC2 in peripheral blood mononuclear cells (PBMCs) were measured by real-time polymerase chain reaction (PCR), enzyme-linked immunosorbent assay (ELISA), and flow cytometry. The ILC2s were sorted and the mRNA expression of IL-18 receptor in ILC2 was analyzed by real-time PCR. The effects of IL-18 on the proliferation and type 2 cytokine production were detected by tritiated thymidine incorporation test, real-time PCR, and ELISA, respectively. The levels of IL-18 mRNA and protein were significantly higher in AR patients than in the controls (P<0.05). The frequency of ILC2 in peripheral blood was elevated in the AR patients than in the controls. After stimulation by IL-18 and house dust mite (HDM), the expression of IL-18 receptor (IL-18R) by ILC2 was significantly up-regulated. The tritiated thymidine incorporation results showed that IL-18 promoted the proliferation of ILC2 in a dose-dependent manner. IL-18 also induced the expression of IL-5 and IL-13 proteins by ILC2. Our results confirmed -for the first time- the effect of IL-18 in innate immunity, which was demonstrated by direct effect on the differentiation and function of ILC2.

The Inhibition of Group II Innate Lymphoid Cell Response by IL-27 in Allergic Rhinitis.

Objectives Interleukin-27 (IL-27) has been reported to inhibit type 2 T helper cell (Th2) response in allergic rhinitis (AR). However, its effects on group II innate lymphoid cells (ILC2) in AR are not fully understood. Methods Nineteen patients with AR and nineteen controls were enrolled in this study. The effects of IL-27 on ILC2 differentiation and function as well as the regulation of the IL-27 receptor (IL-27R) were analyzed by tritiated thymidine incorporation, enzyme-linked immunosorbent assay (ELISA), and real-time polymerase chain reaction (PCR), respectively. AR mice were used to confirm the role of IL-27 in vivo. Results The serum IL-27 protein expression in AR patients was significantly lower compared with controls. IL-27 decreased the ILC2 proliferation and type II cytokine secretion through the interaction with IL-27R. IL-27 also inhibited systemic and nasal ILC2 response of AR mice. Conclusion IL-27 inhibited the proliferation and function of ILC2 in AR, implying that IL-27 may be used as new treatment target in AR.

Insulin enhances neointimal hyperplasia following arterial injury through the PI3K/Akt pathway in type 1 diabetic rats.

Although insulin is known to affect neointimal hyperplasia via distinct signaling pathways, how neointimal hyperplasia is affected in insulin‑deficient type1 diabetes remains unknown. The aim of the current study was to investigate two major signaling branches of insulin action regulating neointimal hyperplasia following arterial injury in type 1 diabetes with or without exogenous insulin administration. Rats were treated with vehicle (control group), streptozotocin(STZ) alone (STZ group; uncontrolled type1 diabetes) or STZ followed by insulin (STZ+I group; controlled type1 diabetes). Subsequently, a type 1 diabetic rat model of carotid artery balloon injury was established. Following this, the intima‑to‑media area ratios were examined for evidence of neointimal hyperplasia in the carotid arteries of the rats by performing hematoxylin‑eosin staining. Furthermore, the protein expression of extracellular signal‑regulated kinase (ERK), phosphorylated(p‑) ERK, protein kinaseB(Akt) and p‑Akt in the carotid arteries of the rats was determined via immunoblotting. Moreover, an invitro model of type1 diabetes was induced by incubation of primary vascular smooth muscle cells (VSMCs) with glucose and/or insulin. Cellular proliferation and signaling protein expression levels in VSMCs were determined by measuring the incorporation of tritiated thymidine and performing immunoblotting, respectively. The results demonstrated that compared with that in control rats, neointimal hyperplasia and expression of p‑Akt in uncontrolled type 1 diabetic rats were significantly decreased. This decrease was recovered in controlled type1 diabetes with insulin therapy. Furthermore, the difference in the expression of p‑ERK between groups was not significant. Additionally, the results of the cell experiments were consistent with those from the animal studies. In conclusion, the preferential signaling along the phosphatidylinositol3‑kinase/Akt pathway of insulin action in response to insulin restoration may contribute to neointimal hyperplasia. The present study provides a novel approach for the further treatment of neointimal hyperplasia in type1 diabetes.

In vivo immuno - and angiomodulatory effects of Aloe arborescens folii recentis extractum siccum (AAES) in mice

Abstract Introduction AAES is a powdered form of Biostymina, herbal medicinal product of Phytopharm Klęka S.A., a water extract of Aloe arborescens Mill. leaves. Aloe arborescens Mill. (woody aloe, tree-like aloe) is known to have several traditional medicinal properties including anti-inflammatory, immunomodulatory, antiviral and antimicrobial activity. Objective The aim of this work was to study the in vivo effect of AAES on cellular (leukocyte-induced cutaneous angiogenesis, LIA test, and proliferative response to PHA) and humoral (anti-SRBC antibody response) immunity in mice. Methods Balb/c mice were fed AAES from 0.5 to 75 mg/kg body mass for seven days before grafting their splenocytes intradermally to F1 (Balb/cxC3H) recipients (LIA test). Neovascular reaction was evaluated 72 h later in dissection microscope. Spleen cell cultures were incubated with 0.5, 1 and 2 μg/ml of PHA. After 48 h of incubation, tritiated thymidine was added. After further 24 h, cells were harvested (Skatron) and incorporation of tritiated thymidine was measured using Beta-scintillation counter. Balb/c mice were fed for 7 days with AAES, then immunized intraperitoneally with 5% SRBC suspension and 7 days later the antibody response was measured with hemagglutination test. Results Neovascular reaction was significantly higher in groups grafted with splenocytes collected from all AAES fed donors than from the controls. The proliferation of splenocytes taken from mice fed AAES at doses ranging from 0.5 mg/kg to 7.5 mg/kg was stimulated in all cultures. Suppression of proliferation was observed in cell cultures derived from mice fed with higher doses of AAES. Stimulation of anti-SRBC antibody production was seen in mice fed both 2.5 and 7.5 mg/kg dose of AAES. Conclusion Powdered form of Biostymina (AAES) might be useful in the treatment of patients with ischaemia of tissues and organs (myocardial infarction, stroke, necrosis) and in deficiency in the production of immune cells and growth factors (infections, chronic wound healing, ulceration and bone fusion).

Preliminary study on prevention and treatment of experimental autoimmune uveitis by blocking CD73 detachment from the surface of retinal pigment epithelial cells with matrix metalloprotein-9 inhibitor

Objective To preliminarily investigate the mechanism of MMP-9 blocking CD73 detachment from RPE cells surface and preventing and treating experimental autoimmune pigment membranitis(EAU). Methods RPE cells isolated from wild-type C57BL/6 and CD73 gene knockout (CD73-/-) mice were cultured in vitro, and treated with lipopolysaccharide and TNF-α to induce CD73 detachment from RPE surface. According to whether MMP-9 inhibitor CTK8G1150 was added at the same time (the final concentration was 5.0 mol/L) or not, RPE cells cultured in the two types of mice were respectively set as MMP-9 inhibitor intervention group and non-intervention control group. The cells in each group were treated with the intervention of a solvent, 1 μmol/Ladenosine monophosphate (AMP), 1 μmol/L AMP, and 3 μmol/L 5' -α,β-methylene adenosine diphosphate (APCP) (AMP+APCP). The stimulating effect of RPE cells in different groups on CD4+ T cell proliferation was detected by tritiated thymidine incorporation. Adoptive immune induced EAU in wild-type B6 mice and CD73-/- mice, respectively. The receptor mice were randomly divided into the MMP-9 inhibitor intervention group and the non-intervention control group, and CTK8G1150 or the solvent were injected into the subretinal cavity 4, 7 and 10 days after adoptive immunity. CD73 mRNA and protein expression in RPE cells of recipient mice were detected by real-time quantitative PCR (RT-PCR) and Western blot. One-way ANOVA was used to analyze all experimental data. Results When the stimulation mode was AMP, the proliferation of CD4+ T cells in the C57BL/6 MMP-9 inhibitor intervention group decreased significantly compared with the nonintervention group (F=13.28, P 0.05). There was no statistically significant difference in the proliferation capacity of CD4+ T cells between the CD73-/- MMP-9 inhibitor intervention group and the non-intervention group (F=5.24, 6.12, 7.04; P>0.05). RT-PCR results showed that there was no statistically significant difference in the relative expression of CD73 mRNA in RPE cells between the MMP-9 inhibitor group and the non-intervention control group(F=6.54, P>0.05). Western blot results showed that the expression of CD73 protein in RPE cells in the MMP-9 inhibitor group of B6 receptor mice was significantly increased compared with the control group (F=15.24, P<0.01). Conclusion MMP-9 inhibitor blocks CD73 detachment from RPE cells surface and has a protective effect on EAU. Key words: Matrix metalloproteinase 9/antagonists & inhibitors; 5'-nucleotidase; Retinal pigment epithelium; Cells, cultured; Uveitis/physiopathology; Animal experimentation

Effect of surface modified reduced graphene oxide nanoparticles on cerebellar granule neurons

Graphene has been the cornerstone material in various disciplines owing to its captivating properties. But graphene also exerts some toxic effects apart from its extraordinary characteristics. Various surface functionalizations on graphene are developed in order to overcome the toxicity. In this background, pluronics functionalization of reduced graphene oxide was done as an effort to modify its colloidal stability. Effect of pluronics functionalized reduced graphene oxide (rGO-P) on cerebellar granule neurons (CGNs) was examined to infer on its neurotoxic potential. Male Wister rats were exposed to rGO-P and were analyzed for acute toxicity and toxicokinetic studies. Immunotoxicity was performed on rGO-P exposed female rats on the 7th day of gestation by tritiated thymidine incorporation assay. CGNs were also isolated from rat newborns born to female rats dams exposed with rGO-P and examined for any subsequent toxic reactions. The findings suggest that CGNs isolated from rat newborns pups born to particle exposed female rats dams showed normal cell yield and morphology. Findings from toxicokinetic studies using confocal Raman mapping revealed that rGO-P has got cleared off from the blood within 21 days. Overall results validate rGO-P as safe for in vivo systems. Hence rGO-P can be fine-tuned to serve the purpose of neurobiological applications promisingly for neuroregeneration.

The effect of sex on immune responses to a homocitrullinated peptide in the DR4-transgenic mouse model of Rheumatoid Arthritis

Rheumatoid Arthritis (RA) is more common and severe in women compared to men. Both women and men with RA express autoantibodies to post-translationally modified antigens, including citrullinated and homocitrullinated proteins or peptides. These autoantibodies are strongly linked with the HLA-DR4 gene. The objective of this study was to determine sex differences in immune responses to homocitrullinated antigens. We used a humanized animal model of RA, DR4-transgenic mice and immunized them with a homocitrullinated peptide called HomoCitJED. Immune responses in these mice were measured for splenocyte proliferation by tritiated thymidine incorporation, serum autoantibody production by ELISA and cytokine levels by multiplex. We found that T cell and antibody responses to homocitrullinated antigens were similar in male and female mice. However, we found sex differences in serum cytokine profiles with female mice having higher ratio of IL-1α to IL-5, suggesting imbalances in immune regulation. This is the first study to report that immune responses to homocitrullinated antigens can be differentiated by sex.

Assessing the Impact of Phytochemicals on Immune Checkpoints: Implications for Cancer Immunotherapy.

Phytochemicals are the basis for many anticancer drugs currently in clinical use, as well as a potential source of future cancer treatments. Some phytochemicals have been found to modify the expression of checkpoint inhibitors of the immune response, as well as kill cancer cells. Cancer cells, in turn, may evade detection by the immune system by expressing molecules such as programmed death ligand 1 (PD-L1) that interacts with programmed cell death 1 (PD-1) on T cells to inhibit T cell activation and effector function. Phytochemicals have direct effects on cancer cells and/or T cells that may impact PD-L1/PD1 interactions, although this may vary depending on the phytochemical in question. Flow cytometric analysis of cancer cells stained with anti-PD-L1 antibodies following treatment with a given phytochemical enables the detection of any alteration in PD-L1 expression. The effect of the phytochemical on T cell function can be assessed using proliferation assays (e.g., tritiated thymidine incorporation, flow cytometric analysis of Oregon Green 488-stained cells) and enzyme-linked immunosorbent assay of interleukin-2 content in culture supernatants. Additional study is needed to better understand the impact of phytochemicals on cancer immunotherapy.

Streptococcal superantigen-induced expansion of human tonsil T cells leads to altered T follicular helper cell phenotype, B cell death and reduced immunoglobulin release.

SummaryStreptococcal pyrogenic exotoxin (Spe) A expression is epidemiologically linked to streptococcal tonsillo‐pharyngitis and outbreaks of scarlet fever, although the mechanisms by which superantigens confer advantage to Streptococcus pyogenes are unclear. S. pyogenes is an exclusively human pathogen. As the leucocyte profile of tonsil is unique, the impact of SpeA production on human tonsil cell function was investigated. Human tonsil cells from routine tonsillectomy were co‐incubated with purified streptococcal superantigens or culture supernatants from isogenic streptococcal isolates, differing only in superantigen production. Tonsil cell proliferation was quantified by tritiated thymidine incorporation, and cell surface characteristics assessed by flow cytometry. Soluble mediators including immunoglobulin were measured using enzyme‐linked immunosorbent assay. Tonsil T cells proliferated in response to SpeA and demonstrated typical release of proinflammatory cytokines. When cultured in the absence of superantigen, tonsil preparations released large quantities of immunoglobulin over 7 days. In contrast, marked B cell apoptosis and abrogation of total immunoglobulin (Ig)A, IgM, and IgG production occurred in the presence of SpeA and other superantigens. In SpeA‐stimulated cultures, T follicular helper (Tfh) cells showed a reduction in C‐X‐C chemokine receptor (CXCR)5 (CD185) expression, but up‐regulation of OX40 (CD134) and inducible T cell co‐stimulator (ICOS) (CD278) expression. The phenotypical change in the Tfh population was associated with impaired chemotactic response to CXCL13. SpeA and other superantigens cause dysregulated tonsil immune function, driving T cells from Tfh to a proliferating phenotype, with resultant loss of B cells and immunoglobulin production, providing superantigen‐producing bacteria with a probable survival advantage.

Survival of lymphocytes is not restricted by IDO-expressing fibroblast from rheumatoid arthritis patients

Objective: Rheumatoid arthritis (RA) is characterized by expansion of fibroblast-like synoviocytes (FLS) in inflamed joints and activation of lymphocytes. Tryptophan (trp) is an essential amino acid indispensable for the biosynthesis of proteins and critical for survival of lymphocytes. Indoleamine 2,3-dioxygenase (IDO) that initiates the degradation of trp and tryptophanyl-tRNA synthetase (TTS) essential for tryptophan synthesis, regulate trp bioavailability. Here, we tested the hypothesis that triggered by cytokines, enhanced IDO activity modulate regulatory function of otherwise non-tolerogenic FLS isolated from RA patients.Materials and methods: IDO and TTS mRNA expression were evaluated by RT-PCR. IDO enzymatic activity was confirmed using HPLC. Resting or PHA-activated PBMC from healthy volunteers and RA patients were co-cultured with IDO expressing untreated (FLSC) or IFNγ-treated (FLSIFNγ) RA FLS. Lymphocyte survival and proliferation were evaluated by flow cytometry analysis and tritiated thymidine incorporation, respectively.Results: RA FLSIFNγ produce functionally active IDO and constitutively express TTS. RA FLSC and FLSIFNγ increased survival of resting lymphocytes in both studied groups, and decreased proliferation of healthy, but not RA, PBMC. Only FLSIFNγ diminished survival of activated CD3+CD4−, but not CD3+CD4+, healthy T cells and similar tendency was observed in rheumatoid cells. Importantly, IDO inhibitor, 1-methyl-DL-tryptophan (1-MT), failed to reverse this effect. PBMC, irrespective of their state (resting versus activated) or origin (healthy or RA), expressed high level of TTS mRNA.Conclusions: We suggest that RA FLS express functionally active IDO but control survival and expansion of healthy cells in IDO-independent mechanism and exert weaker, if any, suppressive effect on rheumatoid cells.

Inhibition of collagen production delays malignant mesothelioma tumor growth in a murine model

Malignant mesothelioma is an aggressive fibrous tumor, predominantly of the pleura, with a very poor prognosis. Cell-matrix interactions are recognized important determinants of tumor growth and invasiveness but the role of the extracellular matrix in mesothelioma is unknown. Mesothelioma cells synthesize collagen as well as transforming growth factor-beta (TGF-β), a key regulator of collagen production. This study examined the effect of inhibiting collagen production on mesothelioma cell proliferation in vitro and tumor growth in vivo. Collagen production by mesothelioma cells was inhibited by incubating cells in vitro with the proline analogue thiaproline (thiazolidine-4-carboxylic acid) or by oral administration of thiaproline in a murine tumor model. Cell cytotoxicity was measured using neutral red uptake and lactate dehydrogenase assays. Proliferation was measured by tritiated thymidine incorporation, and inflammatory cell influx, proliferation, apoptosis and angiogenesis in tumors examined by immunohistochemical labelling. Tumor size was determined by tumor weight and collagen production was measured by HPLC. Thiaproline at non-toxic doses significantly reduced basal and TGF-β-induced collagen production by over 50% and cell proliferation by over 65%. In vivo thiaproline administration inhibited tumor growth at 10 days, decreasing the median tumor weight by 80%. The mean concentration of collagen was 50% lower in the thiaproline-treated tumors compared with the controls. There were no significant differences in vasculature or inflammatory cell infiltration but apoptosis was increased in thiaproline treated tumors at day 10. In conclusion, these observations strongly support a role for collagen in mesothelioma growth and establish the potential for inhibitors of collagen synthesis in mesothelioma treatment.

Differential responses to tritiated thymidine incorporation into DNA between mouse embryonic neural stem cells and fibroblasts

Differential responses to tritiated thymidine incorporation into DNA between mouse embryonic neural stem cells and fibroblasts