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ABSTRACT: Calcineurin B subunit (CnB) is the regulatory subunit of calcineurin (Cn), a Ca(2+)/calmodulin-dependent serine/threonine protein phosphatase. It has been reported that mice deleting the CnB gene lose nearly all Cn activity and show poor tolerance to cardiac stress; CnB gene expression is downregulated in the hearts of rats that have suffered ischemia/reperfusion (I/R) injury. Therefore, we wonder whether injection of exogenous CnB protein can prevent the rats from suffering I/R injury. In cardiomyocytes, fluorogenic labeling shows that exogenous CnB quickly enters the cell. Pretreatment of cardiomyocytes with CnB reduces apoptosis in response to hypoxia/reoxygenation injury (an in vitro model mimicking ischemia/reperfusion injury), and CsA reverses this effect by inhibiting Cn activity. Furthermore, CnB upregulates Bcl-2 and Bcl-XL expression in the process of hypoxia/reoxygenation injury, which may contribute to protecting cardiomyocytes against apoptosis. In vivo experiments shows that pretreatment with CnB improves cardiac contractile function and reduces the frequency of arrhythmias induced by global I/R injury. These findings reveal a novel function for CnB protein in cardiac stress response and suggest a possible application of CnB in coronary disease therapy.
Molecular and Cellular Biochemistry 08/2012; 370(1-2):163-71. · 2.06 Impact Factor
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ABSTRACT: Previous studies have shown that excess calcineurin subunit B (CnB) associates with mitochondria. Here, CnB overexpression increased CN activity in cells and enhanced TNF-alpha-induced cell death independent of CN activity. Overexpression of CnB increased intracellular Ca2+ concentration, enhanced caspase-3 activity, reduced Bcl-2 expression, and decreased mitochondrial membrane potential, with no change of caspase-8 or p53. CnB bound to isolated mitochondria in a Ca(2+)-dependent manner, and stimulated cytochrome c release from the mitochondria. Altogether, these results demonstrate that CnB is capable of promoting TNF-alpha-induced apoptosis, possibly through effects on mitochondrial functions.
Cancer letters 02/2012; 321(2):169-78. · 4.86 Impact Factor
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ABSTRACT: We showed previously that calcineurin B subunit (CnB) could inhibit S180 solid tumor growth in mice and prolong the survival of mice bearing H22 ascites tumors, but the underlying antitumor mechanism remained unclear. Here, we report that the calcineurin B subunit binds to CD11b on RAW264.7 macrophages and induces TRAIL expression and NF-κB activation in a dose and time dependent manner, and that CnB-induced TRAIL expression and NF-κB activation are both dependent on this CD11b. Furthermore, CnB-induced TRAIL expression is mediated by NF-κB. These findings reveal a novel signaling pathway (CnB-CD11b-NF-κB-TRAIL) regulating TRAIL expression and may help to understand the roles of the calcineurin B subunit in the regulation of innate immunity.
Biochemical and Biophysical Research Communications 12/2011; 417(2):777-83. · 2.48 Impact Factor
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ABSTRACT: Calcineurin is the only Ca(2+) /calmodulin-dependent serine/threonine protein phosphatase. The roles of the cytosolic calcineurin have been well researched; however, the roles of the serum calcineurin remain unknown. Here, we report that the recombinant human calcineurin B subunit (CnB) can bind to rabbit platelets and show an antiplatelet aggregation activity. Furthermore, CnB exerts an anticoagulant effect by prolonging the activated partial thromboplastin time and thrombin time and reducing the plasma fibrinogen concentration in a dose-dependent manner. We further reveal that the functional domain associated with the anticoagulant activity of CnB is located in the C-terminus. Hemolysis test and intravenous stimulation study show that the recombinant CnB does not cause obvious hemolysis and is safe for intravenous injection. These results reveal a new function of calcineurin B subunit. They also give an explanation for the roles of calcineurin B subunit in serum and point to a possible implication in antithrombotic therapy.
International Union of Biochemistry and Molecular Biology Life 11/2011; 63(11):1037-44. · 3.51 Impact Factor
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ABSTRACT: Protective immunity involves a dynamic balance between humoral and cellular immune responses. In the present work we demonstrated that recombinant human calcineurin subunit B (rhCnB) stimulated the expression of the surface molecules CD83, CD80, CD86, CD40, and HLA-DR. It also promoted secretion of inflammatory cytokines IL-6, TNF-α, and IL-1β by human PBMC-derived dendritic cells. In in vivo experiments, splenocytes from BALB/c mice immunized with pneumolysin plus rhCnB contained a higher percentage of CD3(+)CD4(+) T lymphocytes, produced more antigen-specific splenocyte proliferation activity, and had higher anti-pneumolysin immunoglobulin G (IgG) titers. Transcript levels of cytokines such as IL-4, IL-10, and IFN-γ in the splenocytes were also upregulated when in vitro stimulated with pneumolysin. Thus, rhCnB promoted a mixed Th1/Th2 type immune response when given together with the specific antigen PN. RhCnB could have potential as a prophylactic vaccine adjuvant.
Immunology letters 06/2011; 140(1-2):52-8. · 2.91 Impact Factor
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ABSTRACT: Safe and potent adjuvants are required to establish effective vaccines. In the present work, we show that calcineurin subunit B promotes the secretion of pro-inflammatory cytokines, such as tumor necrosis factor-α, interleukin-12p70 (IL-12 p70), IL-6 and the chemokine IL-8. It also up-regulates transcript levels of chemokines in bone marrow-derived dendritic cells. In an animal model, C57BL/6 mice were divided into four groups, immunized with ovalbumin (OVA), OVA mixed with calcineurin subunit B (CnB), CnB and PBS, respectively. The splenocytes from mice immunized with OVA in combination with CnB produced higher levels of IFN-γ and CTL when in vitro stimulated with OVA protein. Subcutaneous (s.c.) immunization of C57BL/6 mice with OVA plus CnB conferred greater protection against tumor-forming E.G7-OVA cells than did injection of OVA alone, and the survival rate of mice immunized intraperitoneally was higher than that of mice immunized s.c. Thus, CnB exerts potent adjuvant effects that polarize responses toward T(h)1 and elicit anti-tumor and anti-infection immunity. CnB could be of use as a prophylactic adjuvant as it is a human-derived safe agent and has immune-modulating effects that promote the control of cancer and infectious diseases.
International Immunology 03/2011; 23(5):327-34. · 3.41 Impact Factor
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ABSTRACT: The microstructure of an ultrafine grained mild steel was characterized by X-ray diffraction, scanning electron microscopy, transmission electron microscopy and nanoindentation techniques. The results indicate that with the decrease of grain size within the submicron range, the change of Young’s modulus was obvious, which has been attributed to the variation of lattice constants.
Scripta Materialia.
