The effect of icariin on immunity and its potential application.

Icariin (ICA) is a major bioactive monomer belonging to flavonoid glycosides attracted from Epimedium, being a classic tonic agent in traditional Chinese medicine. ICA commonly presents multiple effects such as regulating sex hormones, relieving atherosclerosis and antioxidant activity, etc. Recently, more and more studies have demonstrated the application of ICA in autoimmune diseases such as rheumatoid arthritis, bronchial asthma, multiple sclerosis and systemic lupus erythematosus due to its anti-inflammatory. Additionally, ICA also has the anti-tumor activities. Multiple targets and mechanisms of ICA are reported which relates to regulate lymphocytes balance, anti-inflammatory/inflammatory cytokines, signal pathways like NF-kappaß and Erk-p38-JNK, lymphocyte transcription factors and other targets such as TLRs, STAT and PTEN, etc. In this review, we have updated the advance in this field and these studies have suggested that ICA has a potential to treat immunological and inflammatory diseases.

[Cloning and Ion Transportation of Cryptosporidium andersoni ATP-binding Cassette 1 Gene].

Objective: To investigate the transportation of intracellular and extracellular K(+), Ca(2+), Na(+) and Mg(2+) under the function of Cryptosporidium andersoni ATP-binding cassette (CaABC) 1 gene. Methods: CaABC1 gene was amplified by PCR using specifically designed primers. The eukaryotic expression plasmid pEGFP-C1-CaABC1 was constructed, and transfected into mouse intestinal epithelial cells via liposome transfection. The blank (with no transfection) and control groups (transfected with empty plasmid pEGFP-C1) were also set. Changes in intracellular and extracellular K(+), Ca(2+), Na(+) and Mg(2+) concentrations were examined by the ion concentration assay kit. Results: PCR amplification resulted in a 544 bp product. The recombinant plasmid pEGFP-C1-CaABC1 was successfully constructed. Green fluorescence was seen in the control and transfected groups, but not in the blank group. The concentrations of K(+), Ca(2+), Na(+) and Mg(2+) in intracellular fluid were （5.51 ± 0.51）, （1.98 ± 0.06）, （108.33 ± 1.33） and （0.93 ± 0.03） mmol/L in the blank group; （6.25 ± 0.70）, （1.90 ± 0.13）, （107.73 ± 1.79） and （0.87 ± 0.05） mmol/L in the control group; and （14.84 ± 0.90）, （3.40 ± 0.14）, （127.64 ± 1.49） and （1.72 ± 0.20） mmol/L in the transfected group. The concentrations of K+, Ca2+, Na+ and Mg2+ in extracellular fluid were （12.72 ± 0.83）, （3.72 ± 0.03）, （116.83 ± 1.04） and (2.02 ± 0.18) mmol/L in the blank group; （10.11 ± 0.90）, （3.58 ± 0.06）, （115.89 ± 1.86） and (1.71 ± 0.41) mmol/L in the control group; and （5.77 ± 0.21）, （1.29 ± 0.18）, （96.21 ± 1.19） and (0.64 ± 0.02) mmol/L in the transfected group. There were significant differences in K+, Ca2+ and Mg2+ concentrations between the transfected group and the control group. Conclusion: CaABC1 participates in the transportation of K+, Ca2+ and Mg2+.

Cloning and Iron Transportation of Nucleotide Binding Domain of Cryptosporidium andersoni ATP-Binding Cassette (CaABC) Gene.

Cryptosporidium andersoni ATP-binding cassette (CaABC) is an important membrane protein involved in substrate transport across the membrane. In this research, the nucleotide binding domain (NBD) of CaABC gene was amplified by PCR, and the eukaryotic expression vector of pEGFP-C1-CaNBD was reconstructed. Then, the recombinant plasmid of pEGFP-C1-CaNBD was transformed into the mouse intestinal epithelial cells (IECs) to study the iron transportation function of CaABC. The results indicated that NBD region of CaABC gene can significantly elevate the transport efficiency of Ca(2+), Mg(2+), K(+), and HCO3 (-) in IECs (P<0.05). The significance of this study is to find the ATPase inhibitors for NBD region of CaABC gene and to inhibit ATP binding and nutrient transport of CaABC transporter. Thus, C. andersoni will be killed by inhibition of nutrient uptake. This will open up a new way for treatment of cryptosporidiosis.

[Detection of immunity and antioxidant indexes in dairy cows infected with Cryptosporidium].

OBJECTIVE: To detect the immune status and antioxidant system indexes of cows infected with Cryptosporidium. METHODS: Fecal samples of 325 dairy cows were collected at a farm in Anhui and examined by floating saturated solution. 7 positive cows and 7 negative cows from the farm were selected as infection group and non-infection group, respectively. Blood samples were taken from cow's jugular vein before feeding in the morning. 19 indexes of total protein (TP), albumin (ALB), IgG, IgM, IgA, phagocytic rate of white blood cells, T lymphocyte transformation rate, IL-2, superoxide dismutase (SOD), glutathione peroxidase (GSH-Px), malondialdehyde (MDA), NO, alanine aminotransferase (ALT), aspartate aminotransferase (AST), alkaline phosphatase (ALP), glucose (GLU), triglyceride (TG), Cl-, and Ca2+ were tested, respectively. RESULTS: The infection rate of 325 cows was 31.7% (103/325). The Cryptosporidium was identified as C. andersoni according to the morphology and size of oocysts. Compared with the non-infection group, there was no significant difference in the concentration of TP, ALB, IgM, IgA, GSH-Px, ALT, AST, ALP and Cl- (P > 0.05). The concentration of MDA and NO in the infection group increased by 59.9% and 28.1% (P < 0.05 or 0.01), and that of IgG, SOD, GLU, TG, Ca2+, IL-2 and the activities of T lymphocyte transformation rate, phagocytic rate of white blood cells decreased by 32.9%, 11.1%, 18.6%, 78.9%, 14.5%, 7.0%, 22.0%, and 20.2%, respectively (P < 0.05). CONCLUSION: The change of antioxidant and immune indexes shows that the capability of eliminating free radicals and the immune function have decreased in the Cryptosporidium andersoni-infected cows.

[Isolation and identification of cow-origin Cryptosporidium isolates in Hefei].

OBJECTIVE: To isolate cow-origin Cryptosporidium in Hefei, and identify its species. METHODS: 285 dairy cattle fecal samples collected from a farm in Hefei were examined by using floating saturated solution of sucrose and modified acid-fast staining. Cryptosporidium oocysts were isolated and purified from positive fecal samples. Genetic DNA was extracted to be the template. According to the sequence of 18S rRNA gene and HSP70 gene from Cryptosporidium sp., the primers were designed and synthesized. The PCR products were amplified by PCR and nested-PCR. The nested PCR products were cloned and sequenced. Homology searches and phylogenic tree construction were done by DNAStar software. RESULTS: Five fecal samples were positive by morphological methods with an infection rate of 1.8% (5/285). Oocysts from the 5 positive fecal samples were elliptical or ovoid detected by using floating saturated solution of sucrose and modified acid-fast staining with the size of 7.37 microm x 6.13 microm and 7.58 microm x 6.20 microm, and a shape index of 1.20 and 1.22, respectively. Nested-PCR resulted in a 18S rRNA and HSP70 gene fragments with approximately 250 bp and 325 bp, respectively. The five isolates showed a high level of nucleic acid identity with sequence data of the 18S rRNA gene of Cryptosporidium andersoni (DQ989573), and they were clustered in the same clade. The highest HSP70 gene sequence identity was found among the five isolates and other reported C. andersoni isolates (AY954892 and DQ989576), and they were placed into the same clade. CONCLUSION: The cow-origin Cryptosporidium isolates derived from Hefei is Cryptosporidium andersoni.

[Research progress on nutrient transport and metabolism of Cryptosporidium].

Cryptosporidiosis is a worldwide zoonotic disease, and Cryptosporidium is coccidia-like parasite that develops in epithelial cells in digestive and respiratory tracts of human and animals. This review summarizes the specific function structure of Cryptosporidium, nutrient uptake, transport, metabolism, and the impact of Cryptosporidium on host nutrient absorption.

TGF-beta requires CTLA-4 early after T cell activation to induce FoxP3 and generate adaptive CD4+CD25+ regulatory cells.

Although positive CD28 costimulation is needed for the generation of natural CD4+CD25+ regulatory T cells, we report that negative CTLA-4 costimulation is necessary for generating phenotypically and functionally similar adaptive CD4+CD25+ suppressor cells. TGF-beta could not induce CD4+CD25- cells from CTLA-4(-/-) mice to express normal levels of FoxP3 or to develop suppressor activity. Moreover, blockade of CTLA-4 following activation of wild-type CD4+ cells abolished the ability of TGF-beta to induce FoxP3-expressing mouse suppressor cells. TGF-beta accelerated expression of CTLA-4, and time course studies suggested that CTLA-4 ligation of CD80 shortly after T cell activation enables TGF-beta to induce CD4+CD25- cells to express FoxP3 and develop suppressor activity. TGF-beta also enhanced CD4+ cell expression of CD80. Thus, CTLA-4 has an essential role in the generation of acquired CD4+CD25+ suppressor cells in addition to its other inhibitory effects. Although natural CD4+CD25+ cells develop normally in CTLA-4(-/-) mice, the lack of TGF-beta-induced, peripheral CD4+CD25+ suppressor cells in these mice may contribute to their rapid demise.

Transfer of regulatory T cells generated ex vivo modifies graft rejection through induction of tolerogenic CD4+CD25+ cells in the recipient.

Certain CD4+CD25+ T cells can induce and maintain T-cell non-responsiveness to donor alloantigens and have therapeutic potential in solid organ transplantation. Peripheral CD4+CD25- cells alloactivated with IL-2 and transforming growth factor beta (TGF-beta) ex vivo express the transcription factor FoxP3, and become potent antigen-specific CD4+CD25- suppressor cells. Here we report that the transfer of TGF-beta-induced regulatory CD4+ and CD8+ T cells (Tregs) co-incident with transplantation of a histoincompatible heart resulted in extended allograft survival. To account for this result, we injected non-transplanted mice with a single dose of CD4+ and CD8+ Tregs and transferred donor cells every 2 weeks to mimic the continuous stimulation of a transplant. We observed increased splenic CD4+CD25+ cells that were of recipient origin. These cells rendered the animals non-responsive to donor alloantigens by an antigen-specific and cytokine-dependent mechanism of action. Both the increased number of CD4+CD25+ cells and their tolerogenic effect were dependent on continued donor antigen boosting. Thus, Tregs generated ex vivo can act like a vaccine that generates host suppressor cells with the potential to protect MHC-mismatched organ grafts from rejection.

Natural and induced CD4+CD25+ cells educate CD4+CD25- cells to develop suppressive activity: the role of IL-2, TGF-beta, and IL-10.

Thymus-derived, natural CD4(+)CD25(+) regulatory T cells can educate peripheral CD4(+)CD25(-) cells to develop suppressive activity by poorly understood mechanisms. TGF-beta has IL-2-dependent costimulatory effects on alloactivated naive, human CD4(+) T cells and induces them ex vivo to become potent contact-dependent, cytokine-independent suppressor cells. In this study, we report that CD4(+)CD25(+) cells are the targets of the costimulatory effects of IL-2 and TGF-beta. These cells do not divide, but, instead, greatly increase the numbers of CD4(+)CD25(-) cells that become CD25(+) cytokine-independent suppressor cells. These CD4(+)CD25(+) regulatory cells, in turn, induce other alloactivated CD4(+)CD25(-) cells to become potent suppressor cells by mechanisms that, surprisingly, require both cell contact and TGF-beta and IL-10. The suppressive effects of these secondary CD4(+)CD25(+) cells depend upon TGF-beta and IL-10. Moreover, both the naive CD4(+) cells induced by IL-2 and TGF-beta to become suppressor cells, and the subsequent CD4(+)CD25(-) cells educated by them to become suppressors express FoxP3. We suggest that the long-term effects of adoptively transferred natural-like CD4(+)CD25(+) regulatory cells induced ex vivo are due to their ability to generate new cytokine-producing CD4(+) regulatory T cells in vivo.

Regulatory T cells generated ex vivo as an approach for the therapy of autoimmune disease.

Regulatory T cells control the reactivity of potentially harmful, self-reactive T cells and prevent autoimmune diseases. Significant progress has been made in the identification, derivation, and mechanism of action of T regulatory cells, previously called suppressor T cells. Heterogeneous T regulatory subsets can be grouped into naturally occurring and those induced in the periphery. Here, we consider whether we can harness T regulatory cells to function as a therapeutic agent for patients with established autoimmune diseases. Since the principal function of thymus-derived, natural CD4+CD25+ cells is to prevent autoimmunity, this subset would be an obvious choice. Besides their contact-dependent, cytokine-independent mechanism of action, they can also induce other CD4+ cells to become suppressor cells. However, only few natural CD4+CD25+ cells circulate in human peripheral blood. Alternatively, one can use IL-2 and TGF-beta to generate large numbers of CD4+CD25+ regulatory T cells ex vivo from naive T cells. These cells have the phenotypic and functional properties similar to natural CD4+CD25+ cells, including the capacity to induce CD4+CD25- cells to develop suppressive activity. These natural-like CD4+CD25+ regulatory T cells are the product of separate effects of IL-2 and TGF-beta on both natural CD4+CD25+ and CD4+CD25- cells. The ability of natural-like CD4+CD25+ cells to induce other CD4+CD25- cells to develop suppressive activity is both contact-dependent and cytokine-dependent. Thus, the effects of IL-2 and TGF-beta on both natural CD4+CD25+ cells and CD4+CD25- cells may trigger a continuous loop which results in the renewal of antigen-specific CD4+ regulatory T cells. These studies suggest that the adoptive transfer of CD4+ T regulatory cells generated ex vivo with IL-2 and TGF-beta as a treatment for autoimmune diseases may have sustained, long-term beneficial effects.

CD4+ and CD8+ regulatory T cells generated ex vivo with IL-2 and TGF-beta suppress a stimulatory graft-versus-host disease with a lupus-like syndrome.

Regulatory T cells generated ex vivo from conventional mouse T cells have been used to prevent and alter the course of a stimulatory graft-vs-host disease with a lupus-like syndrome. DBA/2 mouse T cells induce this syndrome when injected into (DBA/2 x C57BL/6) F(1) mice. Stimulating DBA/2 T cells with irradiated C57BL/6 in the presence of IL-2 and TGF-beta induced both CD4(+) and CD8(+) cells to develop potent suppressive activity and enhanced their survival. The IL-2 and TGF-beta-treated T cells lost their ability to induce graft-vs-host disease and, instead, prevented other parental T cells from inducing lymphoid hyperplasia, B cell activation, and an immune complex glomerulonephritis. Moreover, a single transfer of TGF-beta-conditioned T cells to animals that had already developed anti-dsDNA Abs decreased the titer, suppressed proteinuria, and doubled survival. This study raises the possibility that autologous regulatory T cells generated ex vivo have the potential to be used as an adoptive immunotherapy to induce allograft tolerance and to control autoimmunity.

Celecoxib inhibits proliferation and induces apoptosis via prostaglandin E2 pathway in human cholangiocarcinoma cell lines.

AIM: To evaluate the roles and mechanisms of celecoxib in inducing proliferation inhibition and apoptosis of human cholangiocarcinoma cell lines. METHODS: Cyclooxygenase-2-overexpressing human cholangiocarcinoma cell line QBC939 and cyclooxygenase-2-deficient human cholangiocarcinoma cell line SK-CHA-1 were used in the present study. The anti-proliferative effect was measured by methabenzthiazuron (MTT) assay; apoptosis was determined by transferase-mediated dUTP nick end labeling (TUNEL) detection and transmission electron microscopy (TEM). Cell cycle was analyzed by flow cytometry (FCM). The PGE(2) levels in the supernatant of cultured cholangiocarcinoma cells were quantitated by enzyme-linked immunoabsordent assay (ELISA). RESULTS: Celecoxib suppressed the production of PGE(2) and inhibited the growth of QBC939 cells. Celecoxib at 10, 20, and 40 micromol/L inhibited PGE(2) production by 26 %, 58 %, and 74 % in QBC939 cells. The PGE(2) level was much lower constitutively in SK-CHA-1 cells (18.6+/-3.2) compared with that in QBC939 (121.9+/-5.6) cells (P<0.01) and celecoxib had no significant influence on PGE(2) level in the SK-CHA-1 cells. The PGE(2) concentration in SK-CHA-1 cells also reduced but not significantly after treatment with celecoxib. The PGE(2) concentration in SK-CHA-1 cells was (16.5+/-2.9) ng/well, (14.8+/-3.4) ng/well, (13.2+/-2.0) ng/well and (12.6+/-3.1) ng/well respectively, when pre-treated with 1 micromol/L, 10 micromol/L, 20 micromol/L and 40 micromol/L of celecoxib for 48 h (P>0.05, vs control). The anti-proliferation effect of celecoxib (20 micromol/L) on QBC939 cells was time-dependent, it was noticeable on day 2 (OD490=0.23+/-0.04) and became obvious on day 3 (OD490=0.31+/-0.07) to day 4 (OD490= 0.25+/-0.06), and the OD490 in the control group (day 1) was 0.12+/-0.03 (P<0.01, vs control). The anti-proliferation effect of celecoxib could be abolished by the addition of 200 pg/mL PGE(2). The proliferation of SK-CHA-1 cells was inhibited slightly by celecoxib, the cell density OD490 in the presence of celecoxib and in control group was 0.31+/-0.04 and 0.42+/-0.03 respectively on day 2 (P>0.05), 0.58+/-0.07 and 0.67+/-0.09 respectively on day 3 (P>0.05), and 0.71+/-0.08 and 0.78+/-0.06 respectively on day 4 (P>0.05). Celecoxib induced proliferation inhibition and apoptosis by G(1)-S cell cycle arrest: the percentage of QBC939 cells in G(0)-G(1) phase after treatment with 40 micromol/L (74.66+/-6.21) and 20 micromol/L (68.63+/-4.36) celecoxib increased significantly compared with control cells (54.41+/-5.12, P<0.01). The percentage of SK-CHA-1 cells in G(0)-G(1) phase after treatment with various concentrations of celecoxib didn't change significantly compared with control cells. The TUNEL index was much higher in QBC939 cells treated with 20 micromol/L celecoxib for 2 d (0.063+/-0.018) and for 4 d (0.102+/-0.037) compared with control cells (0.017+/-0.004, P<0.01). CONCLUSION: The current in vitro study indicates that inhibition of proliferation and induction of apoptosis in human cholangiocarcinoma cells by cyclooxygenase-2 specific inhibitor celecoxib may involve in COX-dependent mechanisms and PGE(2) pathway. Celecoxib as a chemopreventive and chemotherapeutic agent might be effective primarily on COX-2-expressing cholangiocarcinoma.

Expression of cyclooxygenase-1 and -2 in extra-hepatic cholangiocarcinoma.

OBJECTIVE: To investigate the expression of cyclooxygenase-1 (COX-1) and cyclooxygenase-2 (COX-2) in extra-hepatic cholangiocarcinoma and the relationship between their expression and clinicopathological parameters. METHODS: COX-1 and COX-2 were detected in 56 extra-hepatic cholangiocarcinomas, including 31 matched tissues originating from non-tumorous bile ductal tissue adjacent to tumours and 6 normal bile ductal tissues, by immunohistochemistry strept avidin-biotin complex using isozyme selective antibodies. RESULTS: There was no difference in expression of COX-1 between carcinomas (96%, 54/56) and noncancerous specimens (94%, 29/31, P>0.05) or normal bile ductal tissues (100%, 6/6, P>0.05). The positive rate of COX-2 expression in extra-hepatic cholangiocarcinomas (86%, 48/56) was significantly higher than their matched tissues (39%, 12/31, P<0.01) and normal bile ductal tissues (0%, 0/6, P<0.01). Overexpression of COX-2 in extra-hepatic cholangiocarcinoma was related to the metastasis of lymph nodes, distant organs or tissues (P<0.05) as well as the degree of tumour differentiation (P<0.05). CONCLUSIONS: The overexpression of COX-2 plays a crucial role in the carcinogenesis and development of extra-hepatic cholangiocarcinoma, indicating that COX-2 may serve as a target for chemoprevention of extra-hepatic cholangiocarcinoma.