Streptococcus mutans PrsA mediates AtlA secretion contributing to extracellular DNA release and biofilm formation in the pathogenesis of infective endocarditis.

The role of secretion chaperone-regulated virulence proteins in the pathogenesis of infective endocarditis (IE) induced by viridans streptococci such as Streptococcus mutans is unclear. In this study, we investigated the contribution of the foldase protein PrsA, a putative parvulin-type peptidyl-prolyl isomerase, to the pathogenesis of S. mutans-induced IE. We found that a prsA-deficient strain had reduced virulence in terms of formation of vegetation on damaged heart valves, as well as reduced autolysis activity, eDNA release and biofilm formation capacity. The secretion and surface exposure of AtlA in vitro was reduced in the prsA-deficient mutant strain, and complementation of recombinant AtlA in the culture medium restored a wild type biofilm phenotype of the prsA-deficient mutant strain. This result suggests that secretion and surface localization of AtlA is regulated by PrsA during biofilm formation. Together, these results demonstrate that S. mutans PrsA could regulate AtlA-mediated eDNA release to contribute to biofilm formation in the pathogenesis of IE.

Aberrant regulation of Wnt signaling in hepatocellular carcinoma.

Hepatocellular carcinoma (HCC) is one of the most lethal malignancies in the world. Several signaling pathways, including the wingless/int-1 (Wnt) signaling pathway, have been shown to be commonly activated in HCC. The Wnt signaling pathway can be triggered via both catenin ß1 (CTNNB1)-dependent (also known as "canonical") and CTNNB1-independent (often referred to as "non-canonical") pathways. Specifically, the canonical Wnt pathway is one of those most frequently reported in HCC. Aberrant regulation from three complexes (the cell-surface receptor complex, the cytoplasmic destruction complex and the nuclear CTNNB1/T-cell-specific transcription factor/lymphoid enhancer binding factor transcriptional complex) are all involved in HCC. Although the non-canonical Wnt pathway is rarely reported, two main non-canonical pathways, Wnt/planar cell polarity pathway and Wnt/Ca(2+) pathway, participate in the regulation of hepatocarcinogenesis. Interestingly, the canonical Wnt pathway is antagonized by non-canonical Wnt signaling in HCC. Moreover, other signaling cascades have also been demonstrated to regulate the Wnt pathway through crosstalk in HCC pathogenesis. This review provides a perspective on the emerging evidence that the aberrant regulation of Wnt signaling is a critical mechanism for the development of HCC. Furthermore, crosstalk between different signaling pathways might be conducive to the development of novel molecular targets of HCC.

ATP13A2 variability in Taiwanese Parkinson's disease.

Mutations in ATP13A2 have been reported to associate with Parkinson's disease (PD). This study investigates the contribution of genetic variants in ATP13A2 to Taiwanese PD. ATP13A2 cDNA fragments from 65 early onset PD (onset <50 years) were sequenced. The identified variants were validated in a cohort of PD (n = 493) and ethnically matched controls (n = 585). A novel heterozygous G1014S, located at the conserved seventh transmembrane domain of ATP13A2 protein, was identified in an early onset PD patient, which was absent in 585 normal controls. Additionally, a reported heterozygous A746T was found in two PD patients and four controls. The clinical features and 99mTc-TRODAT-1 single photon emission computed tomography (SPECT) image of the patients carrying G1014S and A746T were similar to that of idiopathic PD. One normal control with A746T showed an asymmetric reduction of 99mT TRODAT-1 uptake in the right striatum. Under oxidative stress or apoptotic stimulus, lymphoblastoid cells carrying either A764T or G1014S showed increased caspase 3 activity compared with the controls. The rates of decay for G1014S and A746T proteins were more or less reduced in cycloheximide chase experiment. In silico modeling of G1014S exhibited a more stable feature than wild-type, and G1014S is mislocalized mainly in the intralysosomal space, which is coherent with the prediction of prohibiting N-myristoylation and membrane association. We therefore hypothesize that rare variants of ATP13A2 may contribute to PD susceptibility in Taiwan. The role played by ATP13A2 variants in PD remains to be clarified.

[Changes of spleen cytokines in mice immunized with recombinant Bb-Eg95-EgA31 vaccine against Echinococcus granulosus].

OBJECTIVE: To investigate the level of cytokines in spleen from mice immunized with recombinant Bifidobacteria bifidum(Bb)-Eg95-EgA31 vaccine of Echinococcus granulosus (Eg) and challenged with Eg protoscoleces. METHODS: 56 female BALB/c mice were randomly divided into 7 groups: Recombinant Bb-Eg9S-95-EgA31 vaccine subcutaneous injection (group A), intramuscular injection (B), intranasal immunization (C), oral administration (D), blank vector control (E), Bb control (F) and MRS control (G). Mice in all groups were challenged with 50 Eg protoscoleces on the 8th week after vaccination and sacrificed on the 25th week after infection. Spleens were collected to prepare splenocytes, which were cultured under activation of crude Eg antigen (EgAg), with concanavalin A (ConA) or lipopolysaccharide (LPS) stimulation and non-stimulation as control. The splenocyte supernatants were collected to determine the levels of interferon-gamma (IFN-gamma), interleukin-12 (IL-12), tumour necrosis factor-alpha (TNF-alpha) and IL-10 by ELISA. RESULTS: The level of IFN-gamma in groups A [(137.5 +/- 23.2) pg/ml], B [(162.5 +/- 23.2) pg/ml], C [(250.0 +/- 53.5) pg/ml] and D [(215.0 +/- 37.4) pg/ml] was higher than that of group G [(50.0 +/- 10.7) pg/ml] (P < 0.01). The level of IL-12 in groups A [(27.5 +/- 4.6) pg/ml], B [(32.5 +/- 4.6) pg/ml], C [(45.0 +/- 5.4) pg/ml] and D [(35.0 +/- 5.4) pg/ml] was higher than that of group G [(15.0 +/- 5.4) pg/ml] (P < 0.01). The level of TNF-alpha in groups A [(275.0 +/- 46.3) pg/ml], B [(325.0 +/- 46.3) pg/ml], C [(450.0 +/- 53.5) pg/ml] and D [(350.0 +/- 53.5) pg/ml] was higher than that of group G [(150.0 +/- 53.5) pg/ml] (P < 0.01). The level of IL-10 in groups A [(37.5 +/- 4.6) pg/ml], B [(35.0 +/- 5.4) pg/ml], C [(25.0 +/- 5.4) pg/ml] and D [(32.5 +/- 4.6) pg/ml] was lower than that of group G [(45.0 +/- 5.4) pg/ml] (P < 0.05 or P < 0.01). CONCLUSION: The recombinant Bb-Eg95-EgA31 vaccine can induce a protective Th1 type immune response in mice

[Research status on DNA vaccine against Cysticercus cellulosae infection].

DNA vaccine against Cysticercus cellulosae infection is a newly emerging vaccine in recent years. It can induce not only humoral immune response, but also a high level cellular immune response. The DNA vaccine displays prominent advantages in the prevention on cysticercosis. This article reviews the current situation on several DNA vaccines.

[Inhibition on apoptosis of splenocytes in infected mice by immunization with recombinant Bb-Eg95-EgA31 protein of Echinococcus granulosus].

OBJECTIVE: To investigate the weight reduction of hydatid cysts and apoptosis of splenocytes in infected mice by recombinant Bifidobacteria bifidum (Bb)-Eg95-EgA31 protein of Echinococcus granulosus (Eg) and challenged with Eg protoscoleces. METHODS: 56 female BALB/c mice were randomly divided into 7 groups. Groups A and B were injected subcutaneously and intramuscularly respectively with 5 x 10(6) colony-forming unit (CFU) recombinant Bb-Eg95-EgA31 protein, group C was immunized intranasally by 5 x 10(5) CFU protein, group D was vaccinated transgastrically by 5 x 10(8) CFU protein, groups E and F were injected subcutaneously with 5 x 10(6) CFU blank vector [Bb (pGEX-1 lambda T)] and Bb respectively, and group G was injected subcutaneously with 100 microl MRS. Mice in all groups were challenged with 50 Eg protoscoleces on the 8th week after vaccination and sacrificed on the 25th week after infection. The weight of hydatid cysts was measured and weight-reduction rate was calculated. Spleens were collected to prepare splenocytes which were cultured under stimulation with concanavalin A (ConA). The apoptotic rate was determined by flow cytometry (FCM). RESULTS: The average weight of hydatid cysts in groups A [(41.0 +/- 23.0) mg], B [(44.0 +/- 22.0) mg], C [(22.0 +/- 21.0) mg], and D [(28.0 +/- 16.0) mg] was lower than that of group G [(75.0 +/- 33.0) mg] (P<0.05, P<0.01), and there was no significant difference among groups A, B, C and D (P>0.05); no significant difference was found between group G and groups E [(63.0 +/- 30.0) mg], F [(69.0 +/- 22.0) mg] (P>0.05). The apoptotic rate of splenocytes cultured with no ConA in groups A (0.14 +/- 0.01), B (0.14 +/- 0.01), C (0.13 +/- 0.01), and D (0.141 +/- 0.01) was lower than that of group G (0.21 +/- 0.01) (P<0.05); that of group C was lower than groups A, B, and D (P<0.05); there was no significant difference between groups D and A, between groups A and B, and between groups E (0.20 +/- 0.01), F (0.20 +/- 0.01) and group G. The apoptotic rate of splenocytes cultured with ConA in group A (0.19 +/- 0.01), B (0.20 +/- 0.00), C (0.17 +/- 0.01), and D (0.19 +/- 0.01) were lower than that of group G (0.26 +/- 0.01) (P<0.01), that of group C was lower than groups A and B (P<0.01), group C was lower than group D (P<0.05), group D was lower than group B (P<0.05); there was no significant difference between groups A and B, and between groups A and D, and between groups E (0.25 +/- 0.01), F (0.25 +/- 0.01), and group G (P>0.05). The apoptotic rate of splenocytes cultured with ConA was higher than those cultured without ConA (P<0.01). CONCLUSIONS: Apoptosis of splenocytes may be induced by infection of Echinococcus granulosus protoscoleces in mice, while the recombinant Bb-Eg95-EgA31 protein may inhibit the apoptosis of splenocytes in mice challenged with Eg, and induce certain protective immunity in the host.

[Dynamic observation on immune responses in mice administrated with a recombinant Bb-Eg95-EgA31 vaccine of Echinococcus granulosus].

AIM: To dynamically observe the immune responses in mice administrated with a recombinant Bifidobacteria bifidum (Bb)-Eg95-EgA31 vaccine of Echinococcus granulosus. METHODS: BALB/c mice were immunized orally or intranasally by the vaccine. At indicated times after vaccination, the levels of serum IgG, IgG subclass and IgE were determined by ELISA. The levels of IL-12, IFN-gamma, TNF-alpha and IL-10 were measured by ELISA in the supernatant of cultured splenocytes. Proliferation of splenocytes was tested by MTT. The percentage of spleen CD4+ and CD8+ cells was determined by flow cytometry(FCM). RESULTS: The orally immunized mice achieved IgG and IgG3 peaks on 8th week post vaccination, IgG2a peak on 2nd week, IgG2b and IgG1 peaks on 6th week, and IgE peak on 10th week. IFN-gamma and TNF-alpha reached highest level on 4th week, IL-12 on 2nd week, and IL-10 on 6th week. Splenocytes proliferated fastest on 6th week. The percentage of CD4+ cells was peaked on 6th week, while the percentage of CD8+ cells had no obvious change. The intranasally immunized group achieved peaks of IgG, IgG2b and IgE on 10th week, IgG2a peak on 6th week, and peaks of IgG1 and IgG3 on 8th week. IFN-gamma and IL-12 reached highest level on 2nd week, TNF-alpha on 4th week, and IL-10 on 8th week. Splenocytes proliferated fastest on 6th week. The percentage of CD4+ cells was peaked on 6th week, while the percentage of CD8+ cells had no obvious change. CONCLUSION: The recombinant Bb-Eg95-EgA31 vaccine of Echinococcus granulosus induced effective immune responses in mice by either oral vaccination or intranasal inoculation. Our data showed the better immunogenicity of oral vaccination.

[Construction and expression of recombinant plasmid pET28alpha-Sj26GST of Schistosoma japonicum in Escherichia coli BL21].

OBJECTIVE: To construct and express recombinant plasmid pET28a-Sj26GST of Schistosoma japonicum (Sj) in Escherichia coli BL21 (DE3). METHODS: The total RNA was extracted from Sj adult worms by ultrasound-breaking. The Sj26GST antigen gene was amplified by RT-PCR from the total RNA, and then cloned into prokaryotic expression plasmid pET28alpha and transformed into E. coli BL2 (DE3). The BL21(pET28a-Sj26GST) was induced with isopropyl-beta-D-thiogalactopyranosid (IPTG), and the expressed products were analyzed and identified with SDS-PAGE and Western blot. RESULTS: The 676 bp Sj26GST gene was successfully amplified by RT-PCR and cloned into pET28alpha. The recombinant plasmid pET28a-Sj26GST was successfully constructed, with a relative molecular weight of expressed recombinant protein at approximately 36 x 10(3) as determined by SDS-PAGE. The amount of the expressed protein comprised 26% of the total bacterial proteins. The fusion protein could be recognized by the sera of rabbits infected with Sj. CONCLUSION: The recombinant plasmid pET28alpha-Sj26GST is successfully constructed and highly expressed in E. coli in a fused form with His-tag. The expressed fusion protein shows specific antigenicity.

[Dynamic observation on splenocyte subsets in mice immunized with recombinant Bb-Eg95-EgA31 vaccine of Echinococcus granulosus].

OBJECTIVE: To dynamically observe changes of subsets of splenocytes in mice immunized with recombinant Bifidobacteria bifidum (Bb)-Eg95-EgA31 vaccine of Echinococcus granulosus (Eg). METHODS: BALB/c mice were vaccinated by 5 x 10(8) colony forming unit (CFU) orally and 5 x 10(5) CFU intranasally respectively. Mice were killed on week 0, 2, 4, 6, 8, 10, 12, 14, 16, 18 and 20 after immunization respectively, and spleens were separated for cell preparation. CD4+ and CD8+ T cells were determined by flow cytometry (FCM), with MRS as control. RESULTS: In the oral immunization group, CD4+ cells showed a significant increase during the 4th-10th week after vaccination, and reached the highest level on the 6th week, whereas no obvious changes in CD8+ cells numbers were observed. In the intranasal immunization group, CD4+ cells showed an obvious increase during the 4th-8th week after vaccination, and reached the highest level on the 6th week, CD8+ subsets had no obvious changes. CONCLUSION: CD4+ T cell cells may play a key role in immune response in mice immunized with the recombinant Bb-Eg95-EgA31 vaccine of Echinococcus granulosus.

[Research progress in antigens for the diagnosis of alveolar echinococcosis].

Specific antigens of Echinococcus multilocularis is essential for the diagnosis of alveolar echinococcosis and vaccine development. Because of the limited source of nature antigen, its application is restricted. The development of recombinant antigens can provide large amount of antigen under effective quality control. This review summarizes the recent progress in antigen research, especially the recombinant antigen used for diagnosis of the disease.