Blocking NAD(+)/CD38/cADPR/Ca(2+) pathway in sepsis prevents organ damage.

BACKGROUND: Although the nicotinamide adenine dinucleotide (NAD(+))/CD38/cyclic ADP ribose (cADPR)/Ca(2+) signaling pathway has been shown to regulate intracellular calcium homeostasis and functions in multiple inflammatory processes, its role in sepsis remains unknown. The aim of this study was to determine whether the NAD(+)/CD38/cADPR/Ca(2+) signaling pathway is activated during sepsis and whether an inhibitor of this pathway, 8-Br-cADPR, protects the organs from sepsis-induced damage. MATERIALS AND METHODS: Male Sprague-Dawley rats were subjected to cecal ligation and puncture (CLP) or sham laparotomies. NAD(+), cADPR, CD38, and intracellular Ca(2+) levels were measured in the hearts, livers, and kidneys of septic rats at 0, 6, 12, 24, and 48 h after CLP surgery. Rats were also divided into sham, CLP, and CLP+8-Br-cADPR groups, and the hearts, livers, and kidneys were hematoxylin-eosin-stained and assayed for malondialdehyde and superoxide dismutase activities. RESULTS: NAD(+), cADPR, CD38, and intracellular Ca(2+) levels increased in the hearts, livers, and kidneys of septic rats as early as 6-24 h after CLP surgery. Treatment with 8-Br-cADPR inhibited sepsis-induced intracellular Ca(2+) mobilization, attenuated tissue injury, reduced malondialdehyde levels, and increased superoxide dismutase activity in septic rats. CONCLUSIONS: The NAD(+)/CD38/cADPR/Ca(2+) signaling pathway was activated during sepsis in the CLP rat model. Blocking this pathway with 8-Br-cADPR protected hearts, livers, and kidneys from sepsis-induced damage.

[The enhancing effect of "Xuebijing injection" on lipopolysaccharide-induced apoptosis of regulatory T cells and mediation of polarization of helper T cells].

OBJECTIVE: To investigate the enhancing effect of Chinese medicine-Xuebijing injection on lipopolysaccharide (LPS) -induced apoptosis of CD4+ CD25+ regulatory T cells (Tregs) and polarization of helper T cells (Th). METHODS: CD4+ CD25+ Tregs collected from rat spleen in vitro by immunomagnetic beads assay were divided into the control group, anti-CD3/CD28 group, anti-CD3/CD28 + LPS group, anti-CD3/CD28 + "Xuebijing injection" group and anti-CD3/CD28 + LPS + "Xuebijing injection" group. Tregs apoptosis rate and expression of winged helix transcription factor (Foxp3) in Tregs were detected by flow cytometry on 3rd post culture day. CD4+ CD25- T cells were co-cultured with CD4+ CD25- Tregs (1:1) for 68 hours with canavalin A stimulation. Interferon gamma (gamma-IFN), interleukin (IL)-4 and IL-17 in supernatants, which respectively was secreted by Th1, Th2 and Th17, were measured by ELISA. RESULTS: Tregs apoptosis rate of anti-CD3/CD28 + LPS + "Xuebijing injection" group (45.1 +/- 2.7%) was significantly higher than that of anti-CD3/CD28 + LPS group (29.4 +/- 1.6%, P < 0.01). Meanwhile, Foxp3 expressions in Tregs in above 2 groups were 95 +/- 9 and 140 +/- 18 respectively, showing statistically significant difference between them (P < 0.01). Gamma-IFN levels secreted in anti-CD3/CD28 + LPS + "Xuebijing injection" group were significantly higher than those in anti-CD3/CD28 + LPS group (P < 0.01), while IL-4 levels had an opposite tendency compared with gamma-IFN (P < 0.05), resulting in a marked increase in the ra- tio of gamma-IFN/IL-4 in anti-CD3/CD28 + LPS + "Xuebijing injection" group (P < 0.01). In anti-CD3/ CD28 + "Xuebijing injection" group, IL-17 secretion levels were significantly decreased compared with anti-CD3/CD28 group (P < 0.05). CONCLUSIONS: Activation of CD4+ CD25+ Tregs induced by LPS may mediate Th1 shift to Th2 response. "Xuebijing injection" can effectively regulate immune function of T cells, increase the LPS-induced apoptosis of CD4+ CD25+ Tregs as well as enhance the polarization of Th2 to Th1, thereby abating the suppressive state of cell-mediated immunity.

[Effect of apoptosis of CD4+ CD25+ regulatory T cells on proliferation as well as secretion of effector T cells and interventional activity of Xuebijing injection in septic rats].

OBJECTIVE: To investigate the effect of apoptosis of CD4+ CD25+ regulatory T cells (Tregs) on proliferation as well as secretory function of effector T cells (Teff) and potential influence of Xuebijing injection on them in septic rats. METHODS: A sepsis model was reproduced by cecal ligation puncture (CLP), and Wistar rats were randomly divided into the control group (n = 8), sham-operated group (n = 8), CLP group (n = 8), and Xuebijing injection treatment group (n = 8). CD4+ CD25+ Tregs in each group were separated by immunomagnetic beads isolate system on day 3, the apoptosis rate, expression of forkhead/winged helix transcription factor p3 (Foxp3) and cytotoxic T-lymphocyte-associated antigen 4 (CTLA-4) on Tregs were analyzed by flow cytometry, and secretion levels of interleukin (IL)-10 from Tregs were measured by ELISA. Following co-culture of CD4+ CD25+ Treg with CD4+ CD25- T cells (1:1) for 68 hours, proliferative activity of Teff was determined by MTT, and IL-2/sIL-2R alpha levels were measured by ELISA. RESULTS: The apoptosis rate of Tregs in control group was 12.03% +/- 0.89%, which was not significantly different from sham-operated group 9.48% +/- 2.17%. The apoptosis rate of Tregs in CLP group 5.87% +/- 0.44% was lower than that in control group (P < 0.01), and treatment with Xuebijing injection markedly enhanced the apoptosis of Tregs 27.29% +/- 2.48%. Compared to CLP group, expression of Foxp3, CTLA-4, and the secretion of IL-10 of Treg were significantly lowered in Xuebijing injection group (all P < 0.01). The Teff proliferative activity in response to ConA, and IL-2 levels of Teff in CLP group were significantly suppressed compared with control group (P < 0.01), and secretion of sIL-2R alpha in the supernatants was much higher than that of the control group. In comparison to the CLP group, inhibitory rate of Teff proliferative activity and the sIL-2R alpha levels were significantly decreased, while the secretion of IL-2 was increased in Xuebijing injection group (P <0.01). CONCLUSION: CD4+ CD25+ Tregs could markedly upregulate the suppressive function on Teff in sepsis, and treatment with Xuebijing injection effectively enhanced apoptosis of Tregs, thereby down-regulating the suppression on Teff.

[Effect of apoptosis of CD4+ CD25+ regulatory T lymphocytes on polarization of helper T lymphocytes and potential interventional influence of Xuebijing injection in septic rats].

OBJECTIVE: To evaluate the influence of apoptosis of CD4(+)CD25(+) regulatory T lymphocyte (Treg) on polarization of helper T lymphocyte (Th) and effect of Xuebijing injection in septic rats. METHODS: A sepsis model was reproduced by cecal ligation and puncture (CLP). Wistar rats were randomly divided into the normal group (n=8), sham operation group (n=8), model group (n=8) and Xuebijing injection treatment group (n=8). CD4(+)CD25(+)Tregs in each group were separated by immunomagnetic beads isolation system on day 3, the apoptotic rates, expression of forkhead/winged helix transcription factor p3 (Foxp3) as well as cytotoxic T lymphocyte-associated antigen 4 (CTLA-4) of Treg were analyzed by flow cytometry, and the secretion level of interleukin-10 (IL-10) of Tregs was determined by enzyme linked immunosorbent assay (ELISA) after culturing Tregs for 12 hours. Interferon-gamma (IFN-gamma), IL-4, and IL-17 levels, which were respectively secreted by Th1, Th2 and Th17, were measured by ELISA in the supernatant after CD4(+)CD25(+)Tregs were co-cultured with CD4(+)CD25(-)T lymphocytes for 68 hours. RESULTS: The apoptosis rate of the normal group was (12.03+/-0.89)%, which was not significantly different compared with the sham operation group [(9.48+/-2.17)%]. The apoptosis rate of model group [(5.87+/-0.44)%] was much lower than that of the normal and sham operation groups, while the Xuebijing injection treatment group [(27.29+/-2.48)%] had the highest apoptosis rate compared to others (all P<0.01) . The expression of Foxp3, CTLA-4, and the secretion of IL-10 of Treg were negatively correlated with the apoptosis rates, correlation coefficients (r) respectively were -0.878 (P=0.042), -0.877 (P=0.042), and -0.743 (P=0.010). The secretion of IFN-gamma, IL-4 and ratio of IFN-gamma/IL-4 in model group were significantly elevated compared with the normal group [IFN-gamma: (254.70+/-44.88) ng/L vs. (0.68+/-0.78) ng/L , IL-4: (8.82+/-0.61) ng/L vs. (3.48+/-0.98) ng/L, ratio of IFN-gamma/IL-4: 30.28+/- 4.87 vs. 0.23+/-0.30, all P<0.01], and secretion of IFN-gamma as well as ratio of IFN-gamma/IL-4 were markedly higher in Xuebijing injection treatment group [(491.54+/-84.28) ng/L, 45.31+/-8.01, respectively] than in model group (P<0.01 and P<0.05). No marked change in IL-17 levels was noted in various groups (all P>0.05) . CONCLUSION: Due to the apoptosis of Treg, the suppression function of CD4(+)CD25(+)Tregs on CD4(+)T lymphocyte appears to be abated, and treatment with Xuebijing injection could effectively enhance the apoptosis of Tregs, mediating the response of shifting Th2 to Th1.