Apoptosis Of Spleen Cells Research Articles

Effect of FK506 on the immunosuppression of mesenchymal stem cells induced by interferon-γ and tumor necrosis factor-α

Objective To investigate the mechanism of immunosuppressant FK506 on the immunesuppression of mesenchymal stem cells ( MSCs) induced by interferon ( IFN) -γ and tumor necrosis factor (TNF)-α. Methods MSCs pretreated with inflammatory cytokines were co-cultured with mice spleen cells. After incubation with FK506 for 72 h, proliferation of spleen cells was measured by methyl thiazol tetrazolium (MTT) assay and the apoptosis was assessed by flow cytometry. Real-time polymerase chain reaction (PCR) was used to detect the major molecule that mediated the immunosuppression of MSCs and the effect of FK506 on the molecule. Results MSCs pretreated with inflammatory cytokines could inhibit the proliferation of spleen cells and increase the apoptosis of spleen cells, and the apoptosis rate was (53. 5 ±2. 5) % , which was higher than that of MSCs pretreated with IFN-γ or TNF-α and control group ( P ＜0. 05), and IFN-γ and TNF-α upregulated inducible nitric oxide synthase (iNOS) expression in MSCs significantly, and this immunosuppression could also be antagonized by a specific inhibitor 1400W. However,FK506 could inhibit iNOS expression in MSCs pretreated with IFN-γ and TNF-α, the inhibition of spleen cells proliferation by MSCs was reduced significantly, and the apoptosis rate of spleen cells was reduced to (44. 3 ±3. 2)% (P＜0. 05). Conclusion FK506 inhibits the immunosuppression of MSCs through downregulation of iNOS expression in MSCs pretreated with IFN-γ and TNF-α. Key words: Mesenchymal stem cells; Inflammation; Immunosuppression; FK506

Effect of selenium on apoptosis of spleen ceils, T-cell subset of fluorosis chicken

Objective To study the effect of selenium on peripheral and splentic T-cell subset, apoptosis of spleen cells in fluorosis chicken and its mechanism. Methods One hundred and eighty 8-day Hailanhe chicks were randomly divided into 3 groups(each 60): ①control group: 195 mg/kg fluoride and 0.08 mg/kg of selenium; ②fluorine group : 1000 mg/kg fluoride and 0.08 mg/kg of selenium ;③selenium antagonism group : 1000 mg/kg On 30~(th), 60~(th), 90~(th) day, peripheral and splentic CD4~+, CD8~+ T-cell subset analyses underwent flow cytometry and apoptosis of spleen cells were detected by TUNEL for study subjects. Results Compared with control group, the CD4~+ T-cell subset of peripheral in fluorine group was decreased obviously in 30,60,90 days[ (35.36± 4.27)% vs (24.29 ± 2.96)%, (47.65 ± 5.42)% vs (41.62 ± 3.96)%, (49.58 ± 3.98) % vs (42.35 ± 6.03 )%, P < 0.05 or < 0.01 ], CD4~+/CD8~+ ratio also was decreased obviously [ ( 1.701 ± 0.145 )% vs (1.393 ± 0.163)%,(2.712 ± 0.345)% vs (1.781 ± 0.201)%,(2.438 ± 0.356)% vs (1.973 ± 0.229)%, P< 0.05 or < 0.01]. Compared with fluorine group, the CD4~+ T-cell subset of peripheral in selenium antagonism group [ (29.40 ± 3.38)%, (45.40 ± 6.01 )%, (46.85 ± 5.25)%, P < 0.05 or < 0.01 ] was increased obviously in 30,60,90 days,CD4~+/CD8~+ ratio in 60,90 days[(2.004 ±0.314)%,(2.211±0.229)%,all P<0.01]also was increased obviously.Compared with control group,the CD4~+ T-cell subset of spleen cells in fluorine group was decreased obviously in 30,60,90 days[(47.33±5.35)% vs(41.91±4.83)%,(49.28±5.24)% vs(41.26 ±4.56)%,(34.31±4.15)% vs(29.33±2.89)%,all P<0.01],CD4~+/CD8~+ ratio also was decreased obviously[(1.927 ±0.244)% vs(1.525 ±0.265)%,(1.847±0.224)% vs(1.640±0.198)%.(1.265±0.174)% vs(0.878±0.092)%,P<0.05 or<0.01].Compared with fluorine group,the CD4~+ T-cell subset of spleen cells in selenium antagonism group in 60,90 days[(44.87±5.43)%,(32.62±3.37)%,all P<0.05]was increased obviously,CD4~+/CD8~+ ratio in 30,60, 90 days[(1.703 ±0.201)%,(1.772±0.215)%,(0.991±0.124)%,P<0.05 or<0.01]also was increased obviously. The apoptosis ratio of spleen cells in fluorine group in 30,60,90 days[(2.31±0.36)%,(2.76±0.22)%,(3.04± 0.29)%]was higher than that in control group[(1.14±0.21)%,(1.23±0.23)%,(1.29±0.20)%,P<0.01].The apoptosis ratio of spleen cells in selenium antagonism group in 60,90 days[(2.42 ±0.32)%,(2.73±0.39)%]was lower than that in fluorine group(P<0.05 or<0.01).Conclusion A certain concentration of selenium can antagonize the immunity inhibition of fluorine by decreasing apoptosis and improving the unbalance of T-cell subset. Key words: Selenium; Fluodne; Apoptosis; Immunity; T-lymphocyte subsets

Amifostine Protects Bone Marrow from Benzene-Induced Hematotoxicity in Mice

Benzene is one of the most widely used industrial chemical agents. Long-term benzene exposure causes bone marrow aplasia and leads to a wide range of hematopoietic disorders including aplastic anaemia (AA). There are currently no effective approaches to protect people from benzene-induced hematotoxicity and AA. In addition, current treatments for AA have limitations with short- and long-term risks. Protective agents and new therapeutic approaches, therefore, are needed to prevent and treat the disease. Amifostine is a well-known cytoprotective agent and has been widely used in clinical for protecting normal tissues from the toxic effects of chemotherapy and radiotherapy. The authors utilized an established mouse model to determine the protective effect of amifostine on benzene-induced bone marrow hematotoxicity. Whole-blood cell count, morphological and histopathological alterations in the bone marrow and spleen, as well as the production of inducible toxic oxidative species were examined and compared among the mouse groups. Amifostine treatment in benzene-exposed mice significantly improved blood cell counts, and morphological and histopathological signs of hematotoxicity in the bone marrow as well as in the spleen. Moreover, amifostine prevented benzene-induced bone marrow and spleen cell apoptosis and rescinded the inhibition of cell proliferation induced by benzene exposure. Finally, amifostine significantly inhibited the levels of reactive oxidative species and lipid peroxidation induced by benzene exposure. These data suggest that amifostine appears to have substantial protective effect on benzene-induced bone marrow hematotoxicity.

Immunomodulatory Role of Chloroquine and Pyrimethamine in Plasmodium yoelii 17XL Infected Mice

Chloroquine (CLQ) and Pyrimethamine (PYR) are used for the treatment of malaria and some autoimmune diseases; although their mechanism of action is only partially understood, their therapeutic effectiveness in the second case has been attributed to their ability to increase apoptosis of T lymphocytes. In view of the potential for immunomodulation during malaria chemotherapy, we investigated the effects of CLQ and PYR treatment on lymphocyte apoptosis and cytokine expression during infection with blood-stage Plasmodium. This work shows that infection of BALB/c mice with Plasmodium yoelii 17XL (Py17XL) reduced apoptosis in spleen cells but when infected mice were treated with CLQ, apoptosis of B and T lymphocytes increased significantly via a Fas-mRNA expression independent mechanism associated with downregulation of Bcl-2 expression, whereas treatment with PYR increased apoptosis to a lesser extent and only in B lymphocytes. CLQ treatment of Py17XL infected mice upregulated tumour necrosis factor-alpha mRNA expression, while PYR treatment increased interferon-gamma mRNA expression. In infected mice, treatment with CLQ downregulated expression of the anti-inflammatory cytokines, interleukin-10 and transforming growth factor-beta (TGF-beta), while PYR treatment upregulated TGF-beta. Thus, in addition to their anti-malarial effects, both drugs modulate the immune response in malaria by increasing apoptosis and modulating the mRNA expression of cytokines involved in parasite elimination and regulation of inflammatory responses.

Toxoplasma gondii Inhibits Apoptosis in Infected Cells by Caspase Inactivation and NF-κB Activation

Our experiments aimed to clarify the mechanism by which host cell apoptosis is inhibited by infection with the intracellular protozoan parasite, Toxoplasma gondii (T. gondii). Mouse spleen cells were cultured in 6-well plates with RPMI 1640/10% FBS at 37℃, in a 5% CO2 atmosphere. Apoptosis of spleen cells was induced by actinomycin-D (AD) treatment for 1 h prior to infection with T. gondii. A variety of assays were used to assess the progression of apoptosis: DNA size analysis on agarose gel electrophoresis, flow cytometry with annexin V/PI staining, and analysis of expression levels of Bcl-2 family and NF-κB mRNA and proteins by RT-PCR, Western blotting, and EMSA. Additionally, transmission electron microscopy (TEM) was performed to observe changes in cell morphology. Fragmentation of DNA was inhibited in spleen cells treated with AD and T. gondii 5 h and 18 h post infection, respectively, and flow cytometry studies showed a decreased apoptotic rates in AD and T. gondii treated spleen cells. We observed decreased expression of Bax mRNA and protein, while levels of Bcl-2 mRNA remained constant in spleen cells treated with AD and T. gondii. Caspase 3 and PARP were inactivated in cells treated with AD and T. gondii, and increased levels of cleaved caspase 8 were also observed. Analysis of EMSA and Western blot data suggests that activation of transcription factor NF-κB may be involved in the blockade of apoptosis by T. gondii. TEM analysis showed nuclear fragmentation and chromatin condensation occurring in spleen cells treated with AD; however, such apoptosis-associated morphological changes were not observed in cells treated with both AD and T. gondii tachyzoites. Together, these data show that T. gondii infection inhibits AD induced apoptosis via caspase inactivation and NF-κB activation in mouse spleen cells.

Synthesis and immunosuppressive activity of l-rhamnopyranosyl flavonoids

Astilbin, a flavonoid isolated from different plants, shows diverse biological activities. This paper reports the synthesis and immunosuppressive activity of seven analogues of astilbin, which may shed light on the structure-activity relationship of the compounds. The following glycosyl flavonoids, 6-alpha-L-rhamnopyranosyloxyflavanone (20), 3-alpha-L-rhamnopyranosyloxyflavone (22), 3-alpha-L-rhamnopyranosyloxyflavanone (24), 3-alpha-L-rhamnopyranosyloxychromanone (26), 4-alpha-L-rhamnopyranosyloxychromanol (27), 7-hydroxy-3-alpha-L-rhamnopyranosyloxyflavanone (30) and 4'-hydroxy-3-alpha-L-rhamnopyranosyloxyflavanone (32) were prepared respectively by glycosylation of 6-hydroxyflavanone (1), 3-hydroxyflavone (2), 3-hydroxyflavanone (5), 3-hydroxychromanone (8), 4-chromanol (9), 7-benzyloxy-3-hydroxyflavanone (12), 4'-benzyloxy-3-hydroxyflavanone (15). Among them, compounds 5, 8, 12 and 15 were synthesized from flavanone (3), 4-chromanone (6), 7-hydroxyflavanone (10) and 4'-hydroxyflavanone (13) respectively. Similar to astilbin (4), compounds 22, 24, 26, 30 and 32 significantly inhibited the single mixed lymphocytes reaction (sMLR) and enhanced the apoptosis of spleen cells isolated from mice with sheep red blood cell-induced delayed-type hypersensitivity respectively. However, compound 20 only showed a slight tendency to inhibit sMLR at higher concentration. Both compounds 20 and 27 did not influence the cell apoptosis. These data suggest that the following factors play essential roles in determining the biological activity of the flavonoids: the position at which the sugar is linked to the flavone, the presence of carbonyl on C-4 and phenol hydroxyl group in A or B ring. However, the presence of a B ring is unfavorable for the biological activity and the double bond at C2-C3 in C-ring shows little effect on the activity.

Conversion of Trypanosoma cruzi Tc52 released factor to a protein inducing apoptosis

In this study Tc52, a Trypanosoma cruzi released protein, which exerts an immunoregulatory activity, was converted to a molecular form with altered biological function. Indeed, the genetic fusion of Tc52 to a carrier protein, the Shistosoma japonicum glutathione S-transferase (Tc52-Sj26), was shown to induce apoptosis in spleen cells from BALB/c or CBA mice and the human T-cell leukemic cell line (CEM). Cell death by apoptosis was evidenced by the following criteria: (1) increased binding of Annexin V to rTc52-treated spleen cells; (2) the presence of an ordered cleavage of the DNA backbone; (3) double labeling showed increased number of T cells undergoing apoptosis upon incubation with rTc52; (4) the use of a CEM cell line and TUNEL assay allowed to show in situ DNA fragmentation. Surprisingly, intraperitoneal injections of rTc52 to BALB/c mice, which were then infected with T. cruzi, resulted in increased parasiteamia levels and ≅2.5 times increase of macrophages number. Since native Tc52 could not trigger, apoptosis of T cells we could hypothesized that the fusion of Tc52 with Sj26 led to conformational changes resulting in apoptosis inducing properties of rTc52. The possible in vivo physiopathological implications of these finding were discussed.

Effect of 2-amino-2-[2-(4-octylphenyl) ethyl] propane-1,3-diol hydrochloride (FTY 720) on immune liver injury in mice

To investigate the protective effect against two immune liver injury models in mice by 2-amino-2-(2-(4-octylphenyl) ethyl) propane-1,3-diol hydrochloride and its possible mechanisms in Con A-induced liver damage. Liver tissue or hepatocyte injury was monitored biochemically by measuring alanine aminotransferase (sALT) and aspartate aminotransferase (sAST) activity. Hematoxylin and eosin (HE) staining was used for histopathological examination. To evaluate the role of IFN-gamma and IL-4 in the liver injury, serum levels of IFN-gamma and IL-4 were determined using commercially available ELISA kit at 12 h after Con A challenge. We also determined FTY 720-induced spleen cell apoptosis by flow cytometry analysis or spleen cell proliferation test. Different doses of FTY 720 treatment dramatically reduced circulating markers of hepatocyte injury in two kinds of immunological liver injury models. FTY 720 dramatically reduced the elevated serum IFN-gamma and IL-4 levels after Con A injection. Effect of spleen cell supernatants treated with Con A or FTY 720 on hepatocytes showed that ALT activities in cultured hepatocyte supernatants in Con A treatment group increased markedly and FTY 720 could reduce this elevated ALT activities in FTY 720 treatment group. FTY 720 dose-dependently increased the percentage of apoptotic cells in T cells and inhibited splenocyte proliferation induced by Con A. Pretreatment with FTY 720 was shown to produce protective effect on the immune liver injury in mice. The possible mechanism of FTY 720 on Con A-induced liver damage is that it could inhibit lymphocyte proliferation and induce lymphocyte apoptosis, resulting in the reduction of IL-4 or IFN-gamma release, and subsequently protecting liver from being damaged by Con A.

The polysaccharide fraction AIP1 from Artemisia iwayomogi suppresses apoptotic death of the mouse spleen cells in culture.

A polysaccharide fraction, AIP1, purified from Artemisia iwayomogi was shown to have immunomodulating and anti-tumor activities in mice. In order to determine how the AIP1 fraction exhibits the immunomodulating activity, the effect of the fraction on the apoptosis of mouse spleen cells was investigated. Treatment of the mouse spleen cells with the AIP1 fraction resulted in the suppression of apoptotic death and an extension of cell survival in culture, indicating that the fraction might modulate the death of spleen cells. Treatment of the mice with the AIP1 fraction in vivo also resulted in less apoptosis of the spleen cells, which indicates the physiological relevance of the anti-apoptosis effect of the fraction in vitro. A mouse gene array was used to determine the profile of the gene expression change showing a pattern of up- and down-regulated genes by the AIP1 treatment. This study provides preliminary information regarding the immunomodulatory mechanism of the AIP1 fraction.

Modulation of antioxidant enzymes and apoptosis in mice by dietary lipids and treadmill exercise.

The current experiments were designed to study the effect of dietary n-6 and n-3 polyunsaturated fatty acids on antioxidant enzyme activity and dexamethasone (DEX)-induced apoptosis in spleen cells of sedentary (Sed) and treadmill-exercised (Ex) ICR male mice. Two-month-old mice maintained on AIN 76 formula diet, supplemented with either 5% corn oil (CO) or 5% fish oil (FO) diets, were trained on a treadmill to run from 45 to 50 min 1 km/day, 6 days a week for 12 weeks. After 12 weeks of exercise, both Sed and Ex groups were sacrificed. Blood and various tissues, including spleen, were collected asceptically. Increased serum and spleen homogenate peroxide [malondialdehyde (MDA)] levels were observed in mice fed FO (n-3 PUFA) diets, compared to mice fed CO (n-6 PUFA). However, exercise did not alter MDA levels in either CO- or FO-fed mice. Feeding n-3 PUFA significantly increased superoxide dismutase (SOD), catalase, and glutathione peroxidase activity of spleen homogenates. Exercise also significantly increased SOD and peroxidase in CO-fed animals, whereas catalase, glutathione peroxidase, and glutathione transferase were higher in FO-fed mice, compared to the Sed group. Apoptosis and necrosis were quantitated in splenocytes incubated with or without 1 microM Dex in RPMI medium for 8 and 24 hr. Cells were stained with Annexin V and propidium iodide (PI) for apoptotic and necrotic cells. FO-fed mice showed higher apoptosis (64 vs 50%) and necrosis (40 vs 22%) in spleen cells than CO-fed mice. Cells from FO-fed mice, incubated in medium alone, showed increased apoptosis (112%) 24 hr after incubation, and necrosis (37 and 70%) at 8 and 24 hr of incubation, compared to CO-fed mice. In Ex group, apoptosis was increased in both CO- and FO-fed mice only at 24 hr after incubation. In summary, these results indicate that FO (n-3 PUFA-enriched) diets increase apoptosis and antioxidant enzyme activity in spleen cells, probably due to elevated lipid peroxides.

Effects of calorie restriction and ω-3 dietary fat on aging in short-and long-lived rodents.

Aging is accompanied by a steady increase in the incidence of spontaneous tumors and a decline in immune function. Calorie restriction (CR) or supplementation with ω-3 fats prolongs life span, suppresses tumorigenesis, and ameliorates immune function in a variety of experimental models. We suggest that decreased oxidant stress and upregulation of apoptosis mediate the effects of calorie restriction on immunity and longevity. CR prolongs life span in several animal models and our studies have examined the effects of CR on the immune system and on tumorigenesis. CR maintains naive T cells, prevents the rise in "double-negative" T cells, maintains lymphocyte responsiveness to mitogens, and preserves Dexamethasone induced apoptosis in spleen cells of MRL/Ipr mice. CR also modulates the expression of inflammatory mediators and cytokines. CR decreases the Sjögren's syndrome-like chronic inflammation of salivary glands of B/W animals while increasing expression of the immunosuppressive cytokine TGFβ1 and decreasing expression of the pro-inflammatory cytokines IL-6 and TNFα. The autoimmune disease in the B/W mouse also affects the kidneys, and we find that renal expression of platelet derived growth factor-A, (PDGF-A) and thrombin receptor are decreased in CR animals. Similarly, CR decreases the expression and localization of plasminogen activator inhibitor type 1 in glomeruli of B/W animals. CR also modulates expression and function of androgen receptors and the binding of insulin to liver nuclei. Finally, CR suppresses the development of breast tumors in the Ras oncomouse. These effects of calorie restriction are paralleled in short-lived B/W animals fed diets supplemented with ω-3 fatty acids. Omega-3 fatty acids induce the expression of hepatic antioxidant enzymes, and enhance apoptosis in lymphocytes of B/W animals.

Increased dexamethasone-induced apoptosis of thymocytes from mice exposed to long-term extremely low frequency magnetic fields

To address the effect of extremely low frequency electromagnetic fields on programmed cell death we assessed both the spontaneous and dexamethasone (Dex)-induced apoptosis of thymocytes and spleen cells from mice submitted to a long-term continuous exposure of a 0.4-1.0 microT 60 Hz magnetic field or an 8-20 microT direct current (DC) magnetic field. Dex-induced apoptosis but not spontaneous apoptosis was substantially increased in thymocytes from 0.4 to 1.0 microT 60 Hz field-exposed animals. Spontaneous apoptosis and Dex-induced apoptosis of spleen cells were not affected by the 0.4-1.0 microT 60 Hz field exposure. In addition, spontaneous apoptosis and Dex-induced apoptosis of thymocytes and spleen cells from mice exposed to an 8-20 microT DC field were similar to the controls. These findings represent the first demonstration that thymocytes from mice exposed to a long-term 0.4-1.0 microT 60 Hz field may show abnormal response to Dex apoptotic stimuli.

Cytotoxic Actions of FTY720, a Novel Immunosuppressant, on Thymocytes and Brain Neurons Dissociated From the Rat

Effects of FTY720 (2-amino-2-(2-[4-octylphenyl]ethyl)-1,3-propanediol HC1), a novel immunosuppressant, were examined on neurons and thymocytes respectively dissociated from rat brains and thymus glands using a flow cytometer to see if FTY720 exerts cytotoxic actions not only on spleen cells as previously reported but also on the other cells. FTY720 at a concentration of 10 μΜ deteriorated almost all of the thymocytes, while it was not the case for brain neurons. FTY720 increased the intracellular concentration of Ca2+ ([Ca2+]i) of thymocytes in both the presence and absence of external Ca2+, although the [Ca2+]i increased by FTY720 in the presence of external Ca2+ was much greater than that in the absence of external Ca2+. Thus, FTY720 may increase the membrane permeability of Ca2+ and release Ca2+ from intracellular Ca2+ stores in thymocytes. Furthermore, the number of thymocytes stained with ethidium, a dye impermeant to intact membranes, time-dependently increased after drug application. Therefore, FTY720 at concentrations of 3-10 μΜ non-specifically increases the membrane permeability of thymocytes, resulting in necrotic cell death, although FTY720 at micromolar concentrations was reported to induce apoptosis of spleen cells.