miR-182-5p attenuates Schistosoma japonicum-induced hepatic fibrosis by targeting tristetraprolin.

Egg granuloma formation in the liver is the main pathological lesion caused by Schistosoma japonicum infection, which generally results in liver fibrosis and may lead to death in advanced patients. MicroRNAs (miRNAs) regulate the process of liver fibrosis, but the putative function of miRNAs in liver fibrosis induced by S. japonicum infection is largely unclear. Here, we detect a new miRNA, miR-182-5p, which shows significantly decreased expression in mouse livers after stimulation by soluble egg antigen (SEA) of S. japonicum or S. japonicum infection. Knockdown or overexpression of miR-182-5p in vitro causes the increased or decreased expression of tristetraprolin (TTP), an important immunosuppressive protein in the process of liver fibrosis. Furthermore, knockdown of miR-182-5p in vivo upregulates TTP expression and significantly alleviates S. japonicum-induced hepatic fibrosis. Our data demonstrate that downregulation of miR-182-5p increases the expression of TTP in mouse livers following schistosome infection, which leads to destabilization of inflammatory factor mRNAs and attenuates liver fibrosis. Our results uncover fine-tuning of liver inflammatory reactions related to liver fibrosis caused by S. japonicum infection and provide new insights into the regulation of schistosomiasis-induced hepatic fibrosis.

A Long Noncoding RNA, Antisense IL-7, Promotes Inflammatory Gene Transcription through Facilitating Histone Acetylation and Switch/Sucrose Nonfermentable Chromatin Remodeling.

Long noncoding RNAs are important regulators of gene expression in innate immune responses. Antisense IL-7 (IL-7-AS) is a newly discovered long noncoding RNA in human and mouse that has been reported to regulate the expression of IL-6. However, the potential function of IL-7-AS in innate immune system is not fully understood. In this study, we found that the expression of IL-7-AS is primarily dependent on the NF-κB and MAPK signaling pathways in macrophages and intestinal epithelial cells. Functionally, IL-7-AS promotes the expression of several inflammatory genes, including CCL2, CCL5, CCL7, and IL-6, in cells in response to LPS. Specifically, IL-7-AS physically interacts with p300 to regulate histone acetylation levels around the promoter regions of these gene loci. Moreover, IL-7-AS and p300 complex modulate the assembly of SWI/SNF complex to the promoters. IL-7-AS regulates chemotaxis activity of monocytes to intestine epithelial cells with involvement of CCL2. Therefore, our data indicate a new promoting role for NF-κB/MAPK-responsive IL-7-AS in the transcriptional regulation of inflammatory genes in the innate immune system although modulation of histone acetylation around the promoters of related genes.

Mechanism by which the combination of SjCL3 and SjGAPDH protects against Schistosoma japonicum infection.

A vaccine is an important method to control schistosomiasis. Molecules related to lung-stage schistosomulum are considered potential vaccine candidates. We previously showed that glyceraldehyde-3-phosphate dehydrogenase (GAPDH) and cathepsin L3 (CL3) displayed differential expression in the lung-stage schistosomula of Schistosoma japonicum cocultured with host cells. In the present study, we prepared the two proteins and detected the protective effects of SjGAPDH by immunizing mice with this protein alone and in combination with SjCL3 with or without Freund's adjuvant. Then, we investigated the possible mechanisms underlying S. japonicum infection. The results showed that vaccination of adjuvanted SjGAPDH decreased the worm burden (37.8%) and egg load (38.1%), and the combination of adjuvanted SjGAPDH and SjCL3 further decreased the worm burden (65.6%) and egg load (70.9%) during Schistosoma japonicum infection. However, the immunization of a combination of adjuvant-free SjGAPDH and SjCL3 displayed a lower protective effect (< 15%) than those of the adjuvanted SjCL3, the adjuvanted SjGAPDH, and a combination of adjuvanted SjGAPDH and SjCL3. Flow cytometric results showed that the frequency of regulatory T cells (Tregs) was lower (P < 0.05) in the group with adjuvanted SjGAPDH and SjCL3 (2.61%) than the remaining groups. The enzyme-linked immunosorbent assay (ELISA) results indicated that except for the uninfected and infected control groups, the remaining groups displayed a Th1-type shift in immune responses. These results showed the immunization of SjGAPDH resulted in partial protection (approximately 38%); inoculation with a combination of SjCL3 and SjGAPDH in Freund's adjuvant resulted in a high immunoprotective effect (> 65%) against Schistosoma japonicum infection in mice, which was possibly caused by the reduced percentage of Tregs and a Th1-type shift in immune responses; and SjCL3 has no adjuvant-like effect, dissimilar to SmCL3.

Characteristics and function of cathepsin L3 from Schistosoma japonicum.

Schistosomiasis is still prevalent and seriously endangering the health of people and livestock in many countries. There have been great efforts to develop vaccines against schistosomiasis for prolonged protection in epidemic areas. Molecules from lung-stage schistosomula have been regarded as potential vaccine candidates against schistosomiasis. Our previous work has shown that cathepsin L3 from Schistosoma japonicum (SjCL3) is expressed in lung-stage schistosomula, but its role is not well known. In the present study, we characterized SjCL3 and detected its effect as a possible vaccine in vivo and in vitro. From the results of quantitative PCR (qPCR) and western blot, SjCL3 was present throughout the lifecycle of the worm, and its relative expressed level was higher in the liver eggs and adult worms than other stages. Additionally, immunofluorescence assay showed that SjCL3 was mainly concentrated in the eggshell, alimentary canal, and musculature of worms. Compared with the adjuvant group, the immunization of SjCL3 in mice resulted in a 28.9% decrease in worm burden and a 29.2% reduction in egg number in the host liver. In antibody-dependent cell-mediated cytotoxicity (ADCC) insecticidal experiments in vitro, the existence of SjCL3 could in part suppress adherence between macrophages and worm. The above results indicated that the immunization of SjCL3 could induce limited immune protection against S. japonicum infection in mice, and this protease played a role in breaking the process of ADCC, which was beneficial to the survival of worms.

Protein extract from head-foot tissue of Oncomelania hupensis promotes the growth and development of mother sporocysts of Schistosoma japonicum via upregulation of parasite aldolase gene.

Previous studies showed that protein extract from head-foot tissue of Oncomelania hupensis (O. hupensis) (PhfO), when cocultured with mother sporocysts of Schistosoma japonicum (S. japonicum), was beneficial for parasite's growth and development but the underlying mechanisms remain unclear. One possible strategy for PhfO to promote the growth and development of mother sporocysts of S. japonicum is to upregulate parasite's survival genes. Fructose-1,6-bisphosphate aldolase (ALD), an essential enzyme of glycometabolism in the energy metabolism process, plays an important role in the survival and the growth and development of schistosomes. Using an in vitro coculture system, in this study, we analyzed the potential involvement of the ald gene in the growth and development of mother sporocysts of S. japonicum following coculture with PhfO. We found that coculture with PhfO promoted the growth and development and the survival of mother sporocysts, and increased parasites' ATP consumption level. Mother sporocysts cocultured with PhfO showed a significantly increased expression of the ald gene at both RNA and protein levels. The ALD protein mainly expressed in the cytoplasm of mother sporocysts. Knockdown of ald gene in parasites decreased the ALD protein expression and the ATP consumption level, suppressed the growth and development, and attenuated the survival of mother sporocysts. In ald knockdown mother sporocysts, the effects of PhfO on the ALD expression, the ATP consumption level, the growth and development, and the survival of larvae were significantly abolished. Therefore, the data suggest that PhfO could promote the growth and development, and the survival of mother sporocysts of S. japonicum via upregulating the expression of the ald gene.

Attenuation of Intestinal Epithelial Cell Migration During Cryptosporidium parvum Infection Involves Parasite Cdg7_FLc_1030 RNA-Mediated Induction and Release of Dickkopf-1.

Intestinal infection by Cryptosporidium is known to cause epithelial cell migration disorder but the underlying mechanisms are unclear. Previous studies demonstrated that a panel of parasite RNA transcripts of low protein-coding potential are delivered into infected epithelial cells. Using multiple models of intestinal cryptosporidiosis, we report here that C. parvum infection induces expression and release of the dickkopf protein 1 (Dkk1) from intestinal epithelial cells. Delivery of parasite Cdg7_FLc_1030 RNA to intestinal epithelial cells triggers transactivation of host Dkk1 gene during C. parvum infection. Release of Dkk1 is involved in C. parvum-induced inhibition of cell migration of epithelial cells, including noninfected bystander cells. Moreover, Dkk1-mediated suppression of host cell migration during C. parvum infection involves inhibition of Cdc42/Par6 signaling. Our data support the hypothesis that attenuation of intestinal epithelial cell migration during Cryptosporidium infection involves parasite Cdg7_FLc_1030 RNA-mediated induction and release of Dkk1 from infected cells.

A long noncoding RNA, lincRNA-Tnfaip3, acts as a coregulator of NF-κB to modulate inflammatory gene transcription in mouse macrophages.

Long intergenic noncoding RNAs (lincRNAs) are long noncoding transcripts (>200 nt) from the intergenic regions of annotated protein-coding genes. We report here that the lincRNA gene lincRNA-Tnfaip3, located at mouse chromosome 10 proximal to the tumor necrosis factor α-induced protein 3 (Tnfaip3) gene, is an early-primary response gene controlled by nuclear factor-κB (NF-κB) signaling in murine macrophages. Functionally, lincRNA- Tnfaip3 appears to mediate both the activation and repression of distinct classes of inflammatory genes in macrophages. Specifically, induction of lincRNA-Tnfaip3 is required for the transactivation of NF-κB-regulated inflammatory genes in response to bacterial LPSs stimulation. LincRNA-Tnfaip3 physically interacts with the high-mobility group box 1 (Hmgb1), assembling a NF-κB/Hmgb1/lincRNA-Tnfaip3 complex in macrophages after LPS stimulation. This resultant NF-κB/Hmgb1/lincRNA-Tnfaip3 complex can modulate Hmgb1-associated histone modifications and, ultimately, transactivation of inflammatory genes in mouse macrophages in response to microbial challenge. Therefore, our data indicate a new regulatory role of NF-κB-induced lincRNA-Tnfaip3 to act as a coactivator of NF-κB for the transcription of inflammatory genes in innate immune cells through modulation of epigenetic chromatin remodeling.-Ma, S., Ming, Z., Gong, A.-Y., Wang, Y., Chen, X., Hu, G., Zhou, R., Shibata, A., Swanson, P. C., Chen, X.-M. A long noncoding RNA, LincRNA-Tnfaip3, acts as a coregulator of NF-κB to modulate inflammatory gene transcription in mouse macrophages.

Trans-suppression of defense DEFB1 gene in intestinal epithelial cells following Cryptosporidium parvum infection is associated with host delivery of parasite Cdg7_FLc_1000 RNA.

To counteract host immunity, Cryptosporidium parvum has evolved multiple strategies to suppress host antimicrobial defense. One such strategy is to reduce the production of the antimicrobial peptide beta-defensin 1 (DEFB1) by host epithelial cells but the underlying mechanisms remain unclear. Recent studies demonstrate that a panel of parasite RNA transcripts of low protein-coding potential are delivered into infected host cells and may modulate host gene transcription. Using in vitro models of intestinal cryptosporidiosis, in this study, we analyzed the expression profile of host beta-defensin genes in host cells following infection. We found that C. parvum infection caused a significant downregulation of the DEFB1 gene. Interestingly, downregulation of DEFB1 gene was associated with host delivery of Cdg7_FLc_1000 RNA transcript, a C. parvum RNA that has previously demonstrated to be delivered into the nuclei of infected host cells. Knockdown of Cdg7_FLc_1000 in host cells could attenuate the trans-suppression of host DEFB1 gene and decreased the parasite burden. Therefore, our data suggest that trans-suppression of DEFB1 gene in intestinal epithelial cells following C. parvum infection involves host delivery of parasite Cdg7_FLc_1000 RNA, a process that may be relevant to the epithelial defense evasion by C. parvum at the early stage of infection.

Involvement of Cryptosporidium parvum Cdg7_FLc_1000 RNA in the Attenuation of Intestinal Epithelial Cell Migration via Trans-Suppression of Host Cell SMPD3.

Intestinal infection by Cryptosporidium parvum causes inhibition of epithelial turnover, but underlying mechanisms are unclear. Previous studies demonstrate that a panel of parasite RNA transcripts of low protein-coding potential are delivered into infected epithelial cells. Using in vitro and in vivo models of intestinal cryptosporidiosis, we report here that host delivery of parasite Cdg7_FLc_1000 RNA results in inhibition of epithelial cell migration through suppression of the gene encoding sphingomyelinase 3 (SMPD3). Delivery of Cdg7_FLc_1000 into infected cells promotes the histone methyltransferase G9a-mediated H3K9 methylation in the SMPD3 locus. The DNA-binding transcriptional repressor, PR domain zinc finger protein 1, is required for the assembly of Cdg7_FLc_1000 into the G9a complex and associated with the enrichment of H3K9 methylation at the gene locus. Pathologically, nuclear transfer of Cryptosporidium parvum Cdg7_FLc_1000 RNA is involved in the attenuation of intestinal epithelial cell migration via trans-suppression of host cell SMPD3.

Immunization with recombinant schistosome adenylate kinase 1 partially protects mice against Schistosoma japonicum infection.

Highly effective and safe prophylactic vaccines are urgently needed to sustainably control schistosomiasis, one of the most serious endemic zoonoses in China. In this study, we characterized adenylate kinase 1 from Schistosoma japonicum (SjAK1), a phosphotransferase that regulates cellular energy and metabolism, and evaluated its potential as a recombinant vaccine. Based on real-time quantitative PCR, western blot, and immunolocalization, SjAK1 is active throughout the life of the worm, although its expression is higher in 21-day-old schistosomula, adult worms, and eggs deposited in the host liver. Further, the enzyme accumulates in the eggshell, intestinal epithelium, integument of adult worms and in the vitellaria tissue in female worms. A 594-bp full-length complementary DNA (cDNA) encoding SjAK1 was synthesized from total RNA of 3-day-old schistosomes, and immunization with recombinant SjAK1 reduced worm burden by 50%, decreased the density of eggs deposited in the host liver by 40%, and reduced the area of granulomas in the host liver by 56%. ELISA results showed that recombinant SjAK1 also stimulated Th1 cytokines such as IL-2 and IFN-γ, but not IL-5 and IL-4. Collectively, a recombinant form of the enzyme SjAK1 elicits partial protective immunity against Schistosoma japonicum infection and the induction of Th1 cytokines. Thus, the enzyme has potential as a component of a multivalent vaccine against schistosomiasis.

Comparative Metabonomic Investigations of Schistosoma japonicum From SCID Mice and BALB/c Mice: Clues to Developmental Abnormality of Schistosome in the Immunodeficient Host.

The growth and development of schistosome has been affected in the immunodeficient hosts. But it remains unresolved about the molecular mechanisms involved in the development and reproduction regulation of schistosomes. This study tested and compared the metabolic profiles of the male and female Schistosoma japonicum worms collected from SCID mice and BALB/c mice at 5 weeks post infection using liquid chromatography tandem mass spectrometry (LC-MS/MS) platform, in which the worms from SCID mice were the investigated organisms and the worms from BALB/c mice were used as the controls. There were 1015 ion features in ESI+ mode and 342 ion features in ESI- mode were identified after filtration by false discovery rate. Distinct metabolic profiles were found to clearly differentiate both male and female worms in SCID mice from those in BALB/c mice using multivariate modeling methods including the Principal Component Analysis (PCA), Partial Least Squares Discriminant Analysis (PLS-DA), and Orthogonal Partial Least Squares Discriminant Analysis (OPLS-DA). There were more differential metabolites in female worms than in male worms between SCID mice and BALB/c mice. And common and uniquely perturbed metabolites and pathways were identified among male and female worms from SCID mice when compared with BALB/c mice. The enriched metabolite sets of the differential metabolites in male worms between SCID mice and BALB/c mice included bile acid biosynthesis, taurine and hypotaurine metabolism, sphingolipid metabolism, retinol metabolism, purine metabolism, etc. And the enriched metabolite sets of differential metabolites in female worms included retinol metabolism, alpha linolenic acid and linoleic acid metabolism, purine metabolism, sphingolipid metabolism, glutamate metabolism, etc. Further detection and comparison in transcript abundance of genes of the perturbed retinol metabolism and its associated meiosis process in worms identified clues suggesting accumulated retinyl ester and perturbed meiotic process. These findings suggested an association between the schistosome with retarded growth and development in SCID mice and their perturbed metabolites and metabolic pathways, and provided a new insight into the growth and development regulation of S. japonicum worms from the metabolic level, which indicated great clues for discovery of drugs or vaccines against the parasites and disease with more researches.

Comparative serum metabolomics between SCID mice and BALB/c mice with or without Schistosoma japonicum infection: Clues to the abnormal growth and development of schistosome in SCID mice.

The small blood flukes of genus Schistosoma, which cause one of the most prevalent and serious parasitic zoonosis schistosomiasis, are dependent on immune-related factors of their mammalian host to facilitate their growth and development, and the formation of granulomatous pathology caused by eggs deposited in host's liver and intestinal wall. Schistosome development is hampered in the mice lacking just T cells, and is even more heavily retarded in the severe combined immunodeficient (SCID) mice lacking both T and B lymphocytes. Nevertheless, it's still not clear about the underlying regulatory molecular mechanisms of schistosome growth and development by host's immune system. This study, therefore, detected and compared the serum metabolic profiles between the immunodeficient mice and immunocompetent mice (SCID mice vs. BALB/c mice) before and after S. japonicum infection (on the thirty-fifth day post infection using liquid chromatography-mass spectrometry (LC-MS). Totally, 705 ion features in electrospray ionization in positive-ion mode (ESI+) and 242 ion features in ESI- mode were identified, respectively. First, distinct serum metabolic profiles were identified between SCID mice and BALB/c mice without S. japonicum worms infection. Second, uniquely perturbed serum metabolites and their enriched pathways were also obtained between SCID mice and BALB/c mice after S. japonicum infection, which included differential metabolites due to both species differences and differential responses to S. japonicum infection. The metabolic pathways analysis revealed that arachidonic acid metabolism, biosynthesis of unsaturated fatty acids, linoleic acid metabolism, glycosylphosphatidylinositol (GPI)-anchor biosynthesis, alpha-linolenic acid metabolism, glycerophospholipid metabolism, sphingolipid metabolism and purine metabolism were enriched based on the differential serum metabolites between SCID mice and BALB/c mice after S. japonicum infection, which was addressed to be related to the retarded growth and development of S. japonicum in SCID mice. These findings provide new clues to the underlying molecular events of host's systemic metabolic changes on the growth and development of S. japonicum worms, and also provide quite promising candidates for exploitation of drugs or vaccines against schistosome and schistosomiasis.

Trans-suppression of host CDH3 and LOXL4 genes during Cryptosporidium parvum infection involves nuclear delivery of parasite Cdg7_FLc_1000 RNA.

Intestinal infection by Cryptosporidium parvum causes significant alterations in the gene expression profile in host epithelial cells. Previous studies demonstrate that a panel of parasite RNA transcripts of low protein-coding potential are delivered into infected host cells and may modulate host gene transcription. Using in vitro models of human intestinal cryptosporidiosis, we report here that trans-suppression of the cadherin 3 (CDH3) and lysyl oxidase like 4 (LOXL4) genes in human intestinal epithelial cells following C. parvum infection involves host delivery of the Cdg7_FLc_1000 RNA, a C. parvum RNA that has been previously demonstrated to be delivered into the nuclei of infected host cells. Downregulation of CDH3 and LOXL4 genes was detected in host epithelial cells following C. parvum infection or in cells expressing the parasite Cdg7_FLc_1000 RNA. Knockdown of Cdg7_FLc_1000 attenuated the trans-suppression of CDH3 and LOXL4 genes in host cells induced by infection. Interestingly, Cdg7_FLc_1000 was detected to be recruited to the promoter regions of both CDH3 and LOXL4 gene loci in host cells following C. parvum infection. Host delivery of Cdg7_FLc_1000 promoted the PH domain zinc finger protein 1 (PRDM1)-mediated H3K9 methylation associated with trans-suppression in the CDH3 gene locus, but not the LOXL4 gene. Therefore, our data suggest that host delivery of Cdg7_FLc_1000 causes CDH3 trans-suppression in human intestinal epithelial cells following C. parvum infection through PRDM1-mediated H3K9 methylation in the CDH3 gene locus, whereas Cdg7_FLc_1000 induces trans-suppression of the host LOXL4 gene through H3K9/H3K27 methylation-independent mechanisms.

Specific binding of L-ficolin and H-ficolin to apoptotic cells leads to complement activation.

The serum lectins mannose-binding lectin (MBL), L-ficolin, and H-ficolin are recognition molecules in the lectin complement pathway, which play an important role in innate immunity. To assess involvement of the lectin pathway in the clearance of apoptotic cells, we used flow cytometry to quantify binding of MBL, L-ficolin, and H-ficolin to apoptotic HL60, U937, and Jurkat cells induced by actinomycin D. When apoptotic cells were incubated with normal human serum, MBL and L-ficolin bound to all three cell lines tested; moreover, H-ficolin bound to apoptotic Jurkat cells only. Subsequently, C4 and C3 were deposited on apoptotic cells of all three cell lines. MBL, L-ficolin, and H-ficolin binding to apoptotic cells was confirmed by the use of purified proteins. Purified C4 added to apoptotic cells that had bound pure L-ficolin was deposited on the cell surfaces. In L-ficolin-depleted serum, C3 deposition on HL60 or Jurkat cells decreased to approximately 50% or 70%, respectively, in comparison to the serum before L-ficolin depletion. We conclude that L-ficolin, in addition to MBL, recognizes apoptotic cells and activates complement via the lectin pathway. We also observed in vitro binding of L-ficolin and H-ficolin to cC1q receptor (C1q receptor specific for the collagenous region of C1q)/calreticulin, a candidate receptor for the collagenous region of MBL and C1q. Thus, L-ficolin and H-ficolin as well as MBL participate in the clearance of apoptotic cells through complement activation.

Ultrastructure of cultured cells from Schistosoma japonicum.

Ultrastructures and their dynamic changes of the cultured cells from Schistosoma japonicum were observed in the present experiments. Several types-including polygonal, round granular, deltaic fan-shaped and flagellated cells-were found in the cultures. The polygonal cells took a major ratio in the cultures from adult S. japonicum, while the majority from schistosomula was round granular cells. The ultrastuctures on the cell surface were different between the cells from adults and schistosomula. Some papilla-like tubercula, microvilli and pinocytotic vesicles were observed on the surface of adult cells, but none were found on schistosomula cells. However, more or less mitochondria, endoplasmic reticula, ribosomes and glycogen were observed in the cytoplasm of the cultured cells from both adults and schistosomula. Golgi complexes were rarely found. The nucleus was round, with round nucleolus inside and clear pores on the unit membrane. There was much lumpish heterochromatin located near to the nuclear membrane. Cells from different worm tissues had their own organelles. The germ cells, vitelline cells, flame cells, multinucleate subtegumental cells and nerve cells could be observed in the cultures from adults. The vitelline cells were the greatest in number and nerve cells were the least in number among them. Similarly, there were germ cells, sustentacular cells, flame cells, nerve cells, mast cells, muscle cells, multinucleate subtegumental cells, interstitial cells and penetration gland cells in the cultures from the schistomomula. In addition, a few division cells were also found. It indicated that the schistosomula cells had greater potential ability to proliferate than the adult cells in in vitro culture. Along with the prolongation of the culture time, degeneration of schistosomal cell occurred more and more. Generally, the electron density of cultures gradually got lower, the cristae of mitochondria blurred and disappeared and the mitochondria themselves swelled and finally vacuoled completely. Vitelline cells were most sensitive to the changes of the in vitro condition in all cultures. Their degeneration showed the following characteristics: (1) vitelline globules fused each other, the space between vitelline globules and the membrane surrounding them broadened gradually and vitelline globules were released and uncovered; (2) rough-surfaced endoplasmic reticula enlarged, vacuolated and the ribosomes dropped; and (3) the number and volume of lipid increased. The ultrastructural changes of most of the cultures from schistosomula had the following trends: (1) heterochromatin increased and euchromatin decreased gradually; and (2) endoplasmic reticula changed into short tubes and vacuoles and disappeared finally. The degenerative process of the cultures from S. japonicum consisted of necrosis according to the ultrastructural changes of the mitochondria, vitelline globules, chromatin and endoplasmic reticula within the cells. The changes of the above structures could be used to estimate whether the culture conditions were appropriate.

Development of adult worms and granulomatous pathology are collectively regulated by T- and B-cells in mice infected with Schistosoma japonicum.

Schistosoma blood flukes, which cause schistosomiasis affecting 200 million people in the world, are dependent on signals from host CD4(+) T cells to facilitate parasite growth and development in the mammalian host and to induce Th2-biased inflammatory granulomas. B cells, however, are reported to down-regulate granulomatous pathology in schistosomiasis, but not to affect the development of blood flukes together with CD4(+) T lymphocytes. Thus it is not clear whether B cells mediate parasite development, reproduction and egg granuloma formation of schistosomes without the help of CD4(+) T lymphocytes. Using mice that have severe combined immunodeficiency (scid) and mice lacking T cells (nude), we found that the absence of B cells can more seriously hamper the development and paring of adult worms, but granuloma formation of Schistosoma japonicum in scid mice was not down-regulated comparing with that in nude mice. The level of IL-10 in the sera of nude mice was significantly higher than of scid mice at 43 days post infection (p.i.). Thus multiple mechanisms of immune modulation seem to be involved in parasite development and reproduction by helminth-induced regulatory B cells. Our findings have significance for understanding the molecular connections between schistosomes and T- and B-cells, indicating that more research is needed to develop efficient vaccine-based therapies for schistosomiasis.

[Effects of male worm extraction on ultrastructure of cultured vitelline cells from Schistosoma japonicum].

OBJECTIVE: To study the effects of male worm extraction on the proliferation and metabolic activity of cultured vitelline cells from Schistosoma japonicum. METHODS: The 28-day S. japonicum worms were harvested by perfusion. The male and female of them were isolated after asepsis separately. The vitelline glands of female worms were isolated, and the vitelline cells were harvested by the cold digestion, then they were inoculated with the moist system method on the walls of culture flasks. The cultured vitelline cells were randomly divided into test and control groups. The cells in the control group were cultured in routine media and those in the test group were cultured in routine media containing male worm extraction of the concentration of 100 microg/ml. When cultured for 7 days, the cells in both groups were prepared for observation under a transmission electron microscope. RESULTS: In the test group, the numbers of mature vitelline cells were more than those in the control group; the cytoplasm and nucleus of mature vitelline cells were homogeneous stain. The nucleolus and rough-surfaced endoplasm reticula were clear, the intervals of vitelline globules were clear and their numbers could be counted. The number of mitochondria was small and the electron density was low; abundant rough-surfaced endoplasm reticula were found in the immature vitelline cells. There were more immature vitelline cells in the control group. The cytoplasm of the cultured vitelline cells took changes of balloon, especially in mature vitelline cells, vitelline globules fused each other, no mitochondria were found; in immature vitelline cells, the space between vitelline globules and the membrane surrounding them broadened gradually and vitelline globules were released and uncovered; rough-surfaced endoplasmic reticula enlarged, space vacuolated and the ribosomes dropped; and the number of lipid increased. CONCLUSION: The S. japonicum male worm extraction can stimulate the development and survival of the cultured vitelline cells.

Metabolic changes reveal the development of schistosomiasis in mice.

Schistosomiasis is a parasitic zoonosis caused by small trematode worms called schistosomes, amongst which Schistosoma japonicum (S. japonicum) is endemic in Asia. In order to understand the schistosome-induced changes in the host metabolism so as to facilitate early diagnosis of schistosomiasis, we systematically investigated the dynamic metabolic responses of mice biofluids and liver tissues to S. japonicum infection for five weeks using (1)H NMR spectroscopy in conjunction with multivariate data analysis. We were able to detect schistosomiasis at the third week post-infection, which was one week earlier than "gold standard" methods. We found that S. japonicum infection caused significant elevation of urinary 3-ureidopropionate, a uracil catabolic product, and disturbance of lipid metabolism, stimulation of glycolysis, depression of tricarboxylic acid cycle and disruption of gut microbiota regulations. We further found that the changes of 3-ureidopropionate and overall metabolic changes in both urinary and plasma samples were closely correlated with the time-course of disease progression. Furthermore, such changes together with liver tissue metabonome were clearly associated with the worm-burdens. These findings provided more insightful understandings of host biological responses to the infection and demonstrated that metabonomic analysis is potentially useful for early detection of schistosomiasis and comprehension of the mechanistic aspects of disease progression.

The effect of a mutagen (N-methyl-N-nitro-N-nitrosoguanidine) on cultured cells from adult Schistosoma japonicum.

The transforming effect of N-methyl-N-nitro-N-nitrosoguanidine (MNNG) on cultured cells from Schistosoma japonicum (S. japonicum) was studied using mono-factor and orthogonal tests. Under the influence of MNNG, cultured cells grew well, and cell survival time was more than 246 days in low-serum medium. When treated with 3 mug/ml MNNG for 48 h, the number of dividing cells increased significantly as determined by bright-field and scanning electron microscopy (SEM). Under these conditions, abundant microvilli, ruffles, microridges, papillae and blebs were observed on the surface of the induced cells. Treatment with MNNG may overcome existing limitations to get continually proliferating schistosome cells and open the possibility to immortalize isolated cells.