Mucosal-Associated Invariant T Cells Develop an Innate-Like Transcriptomic Program in Anti-mycobacterial Responses.

Conventional T cells exhibit a delayed response to the initial priming of peptide antigens presented by major histocompatibility complex (MHC) proteins. Unlike conventional T cells, mucosal-associated invariant T (MAIT) cells quickly respond to non-peptidic metabolite antigens presented by MHC-related protein 1 (MR1). To elucidate the MR1-dependent activation program of MAIT cells in response to mycobacterial infections, we determined the surface markers, transcriptomic profiles, and effector responses of activated human MAIT cells. Results revealed that mycobacterial-incubated antigen-presenting cells stimulated abundant human CD8+ MAIT cells to upregulate the co-expression of CD69 and CD26, as a combinatorial activation marker. Further transcriptomic analyses demonstrated that CD69+CD26++ CD8+MAIT cells highly expressed numerous genes for mediating anti-mycobacterial immune responses, including pro-inflammatory cytokines, cytolytic molecules, NK cell receptors, and transcription factors, in contrast to inactivated counterparts CD69+/-CD26+/- CD8+MAIT cells. Gene co-expression, enrichment, and pathway analyses yielded high statistical significance to strongly support that activated CD8+ MAIT cells shared gene expression and numerous pathways with NK and CD8+ T cells in activation, cytokine production, cytokine signaling, and effector functions. Flow cytometry detected that activated CD8+MAIT cells produced TNFα, IFNγ, and granulysin to inhibit mycobacterial growth and fight mycobacterial infection. Together, results strongly support that the combinatorial activation marker CD69+CD26++ labels the activated CD8+MAIT cells that develop an innate-like activation program in anti-mycobacterial immune responses. We speculate that the rapid production of anti-mycobacterial effector molecules facilitates MAIT cells to fight early mycobacterial infection in humans.

mTOR has a developmental stage-specific role in mitochondrial fitness independent of conventional mTORC1 and mTORC2 and the kinase activity.

The mammalian target of rapamycin (mTOR), present in mTOR complex 1 (mTORC1) and mTORC2, is a serine/threonine kinase that integrates nutrients, growth factors, and cellular energy status to control protein synthesis, cell growth, survival and metabolism. However, it remains elusive whether mTOR plays a developmental stage-specific role in tissue development and whether mTOR can function independent of its complexes and kinase activity. In this study, by inducible genetic manipulation approach, we investigated the role of mTOR and its dependence on mTOR complexes and kinase activity in mitochondrial fitness of early, progenitor stage (lineage-negative; Lin-) versus later, lineage-committed stage (lineage-positive; Lin+) of hematopoietic cells. We found that oxidative phosphorylation (OXPHOS), ATP production and mitochondrial DNA synthesis were decreased in mTOR-/- Lin- cells but increased in mTOR-/- Lin+ cells, suggesting that mTOR plays a developmental stage-specific role in OXPHOS, ATP production and mitochondrial DNA synthesis. In contrast to mTOR deletion, simultaneous deletion of Raptor, a key component of mTORC1, and Rictor, a key component of mTORC2, led to increased mitochondrial DNA in Lin- cells and decreased mitochondrial DNA and ATP production in Lin+ cells, suggesting that mTOR regulates mitochondrial DNA synthesis in Lin- and Lin+ cells and ATP production in Lin+ cells independent of mTORC1 and mTORC2. Similar to mTOR deletion, deletion of Raptor alone attenuated glycolysis and increased mitochondrial mass and mitochondrial membrane potential in Lin- cells and increased mitochondrial mass and OXPHOS in Lin+ cells, whereas deletion of Rictor alone had no effect on these mitochondrial parameters in Lin- and Lin+ cells, suggesting that mTOR regulates glycolysis and mitochondrial membrane potential in Lin- cells, OXPHOS in Lin+ cells, and mitochondrial mass in both Lin- and Lin+ cells dependent on mTORC1, but not mTORC2. Either Raptor deficiency or Rictor deficiency recapitulated mTOR deletion in decreasing OXPHOS in Lin- cells and glycolysis in Lin+ cells, suggesting that mTOR regulates OXPHOS in Lin- cells and glycolysis in Lin+ cells dependent on both mTORC1 and mTORC2. Finally, mice harboring a mTOR kinase dead D2338A knock-in mutant showed decreased glycolysis in Lin+ cells, as seen in mTOR-/- Lin+ cells, but no change in glycolysis in Lin- cells, in contrast to the decreased glycolysis in mTOR-/- Lin- cells, suggesting that mTOR regulates glycolysis in Lin+ cells dependent on its kinase activity, whereas mTOR regulates glycolysis in Lin- cells independent of its kinase activity.

Inhibition of endocytic lipid antigen presentation by common lipophilic environmental pollutants.

Environmental pollutants as non-heritable factors are now recognized as triggers for multiple human inflammatory diseases involving T cells. We postulated that lipid antigen presentation mediated by cluster of differentiation 1 (CD1) proteins for T cell activation is susceptible to lipophilic environmental pollutants. To test this notion, we determined whether the common lipophilic pollutants benzo[a]pyrene and diesel exhaust particles impact on the activation of lipid-specific T cells. Our results demonstrated that the expression of CD1a and CD1d proteins, and the activation of CD1a- and CD1d-restricted T cells were sensitively inhibited by benzo[a]pyrene even at the low concentrations detectable in exposed human populations. Similarly, diesel exhaust particles showed a marginal inhibitory effect. Using transcriptomic profiling, we discovered that the gene expression for regulating endocytic and lipid metabolic pathways was perturbed by benzo[a]pyrene. Imaging flow cytometry also showed that CD1a and CD1d proteins were retained in early and late endosomal compartments, respectively, supporting an impaired endocytic lipid antigen presentation for T cell activation upon benzo[a]pyrene exposure. This work conceptually demonstrates that lipid antigen presentation for T cell activation is inhibited by lipophilic pollutants through profound interference with gene expression and endocytic function, likely further disrupting regulatory cytokine secretion and ultimately exacerbating inflammatory diseases.

RhoA orchestrates glycolysis for TH2 cell differentiation and allergic airway inflammation.

BACKGROUND: Mitochondrial metabolism is known to be important for T-cell activation. However, its involvement in effector T-cell differentiation has just begun to gain attention. Importantly, how metabolic pathways are integrated with T-cell activation and effector cell differentiation and function remains largely unknown. OBJECTIVE: We sought to test our hypothesis that RhoA GTPase orchestrates glycolysis for TH2 cell differentiation and TH2-mediated allergic airway inflammation. METHODS: Conditional RhoA-deficient mice were generated by crossing RhoA(flox/flox) mice with CD2-Cre transgenic mice. Effects of RhoA on TH2 differentiation were evaluated based on in vitro TH2-polarized culture conditions and in vivo in ovalbumin-induced allergic airway inflammation. Cytokine levels were measured by using intracellular staining and ELISA. T-cell metabolism was measured by using the Seahorse XF24 Analyzer and flow cytometry. RESULTS: Disruption of RhoA inhibited T-cell activation and TH2 differentiation in vitro and prevented the development of allergic airway inflammation in vivo, with no effect on TH1 cells. RhoA deficiency in activated T cells led to multiple defects in metabolic pathways, such as glycolysis and oxidative phosphorylation. Importantly, RhoA couples glycolysis to TH2 cell differentiation and allergic airway inflammation through regulating IL-4 receptor mRNA expression and TH2-specific signaling events. Finally, inhibition of Rho-associated protein kinase, an immediate downstream effector of RhoA, blocked TH2 differentiation and allergic airway inflammation. CONCLUSION: RhoA is a key component of the signaling cascades leading to TH2 differentiation and allergic airway inflammation at least in part through control of T-cell metabolism and the Rho-associated protein kinase pathway.

Gene targeting RhoA reveals its essential role in coordinating mitochondrial function and thymocyte development.

Thymocyte development is regulated by complex signaling pathways. How these signaling cascades are coordinated remains elusive. RhoA of the Rho family small GTPases plays an important role in actin cytoskeleton organization, cell adhesion, migration, proliferation, and survival. Nonetheless, the physiological function of RhoA in thymocyte development is not clear. By characterizing a conditional gene targeting mouse model bearing T cell deletion of RhoA, we show that RhoA critically regulates thymocyte development by coordinating multiple developmental events. RhoA gene disruption caused a strong developmental block at the pre-TCR checkpoint and during positive selection. Ablation of RhoA led to reduced DNA synthesis in CD4(-)CD8(-), CD4(+)CD8(-), and CD4(-)CD8(+) thymocytes but not in CD4(+)CD8(+) thymocytes. Instead, RhoA-deficient CD4(+)CD8(+) thymocytes showed an impaired mitosis. Furthermore, we found that abrogation of RhoA led to an increased apoptosis in all thymocyte subpopulations. Importantly, we show that the increased apoptosis was resulted from reduced pre-TCR expression and increased production of reactive oxygen species (ROS), which may be because of an enhanced mitochondrial function, as manifested by increased oxidative phosphorylation, glycolysis, mitochondrial membrane potential, and mitochondrial biogenesis in RhoA-deficient thymocytes. Restoration of pre-TCR expression or treatment of RhoA-deficient mice with a ROS scavenger N-acetylcysteine partially restored thymocyte development. These results suggest that RhoA is required for thymocyte development and indicate, to our knowledge, for the first time that fine-tuning of ROS production by RhoA, through a delicate control of metabolic circuit, may contribute to thymopoiesis.

Recombinant production, crystallization and preliminary structural characterization of Schistosoma japonicum profilin.

Helminthic parasites of the genus Schistosoma contain a tegumental membrane, which is of crucial importance for modulation of the host immune response and parasite survival. The actin cytoskeleton plays an important role in the function of the tegument. Profilins are among the most important proteins regulating actin dynamics. Schistosoma japonicum possesses one profilin-like protein, which has been characterized as a potential vaccine candidate. Notably, profilins are highly immunogenic molecules in many organisms. Here, the profilin from S. japonicum was expressed, purified and crystallized. A native data set to 1.91 Šresolution and a single-wavelength anomalous diffraction (SAD) data set to a resolution of 2.2 Šwere collected. The crystals belonged to space group P2(1)2(1)2(1), with unit-cell parameters a = 31.82, b = 52.17, c = 59.79 Šand a = 35.29, b = 52.15, c = 59.82 Å, respectively.

Mouse gene targeting reveals an essential role of mTOR in hematopoietic stem cell engraftment and hematopoiesis.

mTOR integrates signals from nutrients and growth factors to control protein synthesis, cell growth, and survival. Although mTOR has been established as a therapeutic target in hematologic malignancies, its physiological role in regulating hematopoiesis remains unclear. Here we show that conditional gene targeting of mTOR causes bone marrow failure and defects in multi-lineage hematopoiesis including myelopoiesis, erythropoiesis, thrombopoiesis, and lymphopoiesis. mTOR deficiency results in loss of quiescence of hematopoietic stem cells, leading to a transient increase but long-term exhaustion and defective engraftment of hematopoietic stem cells in lethally irradiated recipient mice. Furthermore, ablation of mTOR causes increased apoptosis in lineage-committed blood cells but not hematopoietic stem cells, indicating a differentiation stage-specific function. These results demonstrate that mTOR is essential for hematopoietic stem cell engraftment and multi-lineage hematopoiesis.

RhoA of the Rho family small GTPases is essential for B lymphocyte development.

RhoA is a member of the Rho family small GTPases that are implicated in various cell functions including proliferation and survival. However, the physiological role of RhoA in vivo remains largely unknown. Here, we deleted RhoA in the B cell and hematopoietic stem cell (HSC) populations in RhoA(flox/flox) mice with CD19 and Mx promoter-driven Cre expression, respectively. Deletion of RhoA by CD19(Cre/+) significantly blocked B cell development in spleen, leading to a marked reduction in the number of transitional, marginal zone, and follicular B cells. Surprisingly, neither B cell proliferation in response to either LPS or B cell receptor (BCR) engagement nor B cell survival rate in vivo was affected by RhoA deletion. Furthermore, RhoA(-/-) B cells, like control cells, were rescued from apoptosis by BCR crosslinking in vitro. In contrast, RhoA deficiency led to a defect in B cell activating factor (BAFF)-mediated B cell survival that was associated with a dampened expression of BAFF receptor and a loss of BAFF-mediated Akt activation. Finally, HSC deletion of RhoA by Mx-Cre severely reduced proB/preB and immature B cell populations in bone marrow while common lymphoid progenitors were increased, indicating that RhoA is also required for B cell progenitor/precursor differentiation. Taken together, our results uncover an important role for RhoA at multiple stages of B cell development.

Distinct roles of Cdc42 in thymopoiesis and effector and memory T cell differentiation.

Cdc42 of the Rho GTPase family has been implicated in cell actin organization, proliferation, survival, and migration but its physiological role is likely cell-type specific. By a T cell-specific deletion of Cdc42 in mouse, we have recently shown that Cdc42 maintains naïve T cell homeostasis through promoting cell survival and suppressing T cell activation. Here we have further investigated the involvement of Cdc42 in multiple stages of T cell differentiation. We found that in Cdc42(-/-) thymus, positive selection of CD4(+)CD8(+) double-positive thymocytes was defective, CD4(+) and CD8(+) single-positive thymocytes were impaired in migration and showed an increase in cell apoptosis triggered by anti-CD3/-CD28 antibodies, and thymocytes were hyporesponsive to anti-CD3/-CD28-induced cell proliferation and hyperresponsive to anti-CD3/-CD28-stimulated MAP kinase activation. At the periphery, Cdc42-deficient naive T cells displayed an impaired actin polymerization and TCR clustering during the formation of mature immunological synapse, and showed an enhanced differentiation to Th1 and CD8(+) effector and memory cells in vitro and in vivo. Finally, Cdc42(-/-) mice exhibited exacerbated liver damage in an induced autoimmune disease model. Collectively, these data establish that Cdc42 is critically involved in thymopoiesis and plays a restrictive role in effector and memory T cell differentiation and autoimmunity.

[Case-control study of risk factors in cholangiocarcinoma].

OBJECTIVE: To investigate the risk factors of intrahepatic cholangiocarcinoma (ICC) and extrahepatic cholangiocarcinoma (ECC). METHODS: The clinicopathological data of 190 patients with cholangiocarcinomas (61 ICC and 129 ECC) diagnosed and treated in the Peking Union Medical College Hospital between 1998 and 2008 were collected. The clinicopathological data of 380 matched healthy controls were also collected. The information about liver diseases, family history, diabetes, smoking and drinking were recorded and analyzed. RESULTS: The positive rate of HBsAg(+) and anti-HBc(+), HBsAg(-) and anti-HBc(+) and the incidence of choledocholithiasis or hepatolithiasis in ICC patients were 27.9%, 50.8% and 14.8%, respectively. The incidence of diabetes mellitus, cholecystolithiasis, choledocholithiasis or hepatolithiasis and previous cholecystectomy in ECC patients were 18.6%, 15.5%, 18.6% and 13.2%, respectively. The incidences of all above mentioned factors in the ICC or ECC patients were significantly higher than that in the controls (P < 0.05). Compared with the patients with ECC, the ICC patients had a significantly higher cirrhosis rate (P < 0.05). CONCLUSION: Our study results show that choledocholithiasis or hepatolithiasis, liver cirrhosis and chronic HBV infection are possible risk factors for intrahepatic cholangiocarcinoma, while choledocholithiasis or hepatolithiasis, diabetes mellitus, cholecystolithiasis, history of cholecystectomy are risk factors for extrahepatic cholangiocarcinoma.

[Clinical value of "Kou mode of hepatic hilar anastomosis" in resection of type III or IV hepatic hilar cholangiocarcinoma].

OBJECTIVE: To evaluate the surgical technique of "Kou mode of hepatic hilar anastomosis" in the treatment for type III or IV hilar cholangiocarcinoma. METHODS: The clinical data of 89 patients with type III or IV hilar cholangiocarcinoma surgically treated in our department between Jan. 1990 and Jan. 2008 were retrospectively analyzed. Since January 2000, "Kou mode of hepatic hilar anastomosis" was performed for some patients with advanced hilar cholangiocarcinoma. The patients were divided into two groups: group A treated between 1990 and 1999, group B between 2000 and 2008. The rate of resection, therapeutic efficacy and complications in these two groups were compared, respectively. RESULTS: Of the 37 cases with hilar cholangiocarcinoma in group A, 4 were surgically treated (10.8%), with 1 (2.7%) radical resection and 3 (8.1%) palliative resection. Among the 52 cases with hilar cholangiocarcinoma in the group B, 35 (67.3%) received surgical resection, of them 15 (28.8%) underwent radical resection and 20 (38.5%) had palliative resection. Twenty-eight of these 35 cases underwent the "Kou mode of hepatic hilar anastomosis". The resection rate of advanced hilar cholangiocarcinoma in the group B was significantly higher than that in group A (P < 0.05). The complications in the 89 cases included ascites (3 cases), hemobilia (1 case), heart failure (1 case), and wound infection (2 cases). All the patients who were treated with the "Kou mode of hepatic hilar anastomosis" developed bile leakage to a varying degree and recovered after drainage and symptomatic treatment. CONCLUSION: The resection rate of type III or IV advanced hilar cholangiocarcinoma can be remarkably improved by using a novel alternative surgical technique called "Kou mode of hepatic hilar anastomosis". However, the long-term outcome still needs to be determined by close follow-up and further observation.

Schistosoma japonicum: proteomics analysis of differentially expressed proteins from ultraviolet-attenuated cercariae compared to normal cercariae.

Schistosomiasis is considered the most important human helminthiasis in terms of morbidity and mortality. In this study, comparative soluble proteomic analysis of normal cercariae and ultraviolet-irradiated attenuated cercariae (UVAC) from Schistosoma japonicum were carried out in view of the high efficiency of irradiation-attenuated cercariae vaccine. The results revealed that some proteins showed significant differential expression in the parasite after treatment with ultraviolet light. Total 20 protein spots were identified by mass spectrometry, corresponded to five groups according to their functions in the main that were structural and motor proteins (actin, et al.), energy metabolism associated enzymes (glyceraldehydes-3-phosphage dehydrogenase, et al.), signaling transduction pathway-associated molecules (14-3-3 protein, et al.), heat shock protein families (HSP 70 family, et al.), and other functional proteins (20S proteasome). Furthermore, our results indicated that the differential expression of the proteins by ultraviolet irradiation may be, at least partially, acquired by regulating the mRNA levels of corresponding proteins. These results may provide new clues for further exploring the mechanism of protective immunity induced by UVAC and may shed some light on the development of vaccines against schistosomiasis.

Characterization of a profilin-like protein from Schistosoma japonicum, a potential new vaccine candidate.

The tegumental membrane of platyhelminth parasites is of crucial importance for modulation of the host response and parasite survival. A complementary deoxyribonucleic acid (cDNA) containing an open reading frame of 390 bp, which encodes a profilin-like tegumental protein with a theoretical isoelectric point of 6.02 and a molecular weight of 14.42 kDa, had been identified by bioinformatic analysis. The coding region of the cDNA was cloned into the prokaryotic expression vector pGEX-4T-1 and expressed in Escherichia coli. The purified recombinant protein named rSj15 was immunogenic and could elicit a high titer of antibody in mice. Western blot analysis revealed that the protein was differentially expressed during the different growth stages of Schistosoma japonicum. Immunohistochemical analysis localized the protein to the tegument and underlying tissue of the S. japonicum adult worm. The rSj15 could induce the expressions of IL-12 in the cultured mouse dendritic cell.

[Studies on immunomodulation effect of recombinant Sj16 from Schistosoma japonicum on inflammation response of host].

OBJECTIVE: To study the immunomodulation effect of the recombination Sj16 from Schistosoma japonicum (reSj16) on inflammation response of host. METHODS: reSj16 expressed in pGEX-4T-1 was purified by GST purification kit and detected by sodium dodecyl sulfate-polyacrylamide gel electrophoresis (SDS-PAGE) and mass spectra (MS). The immunomodulation effect of reSj16 was observed by means of dimethylbenzene inducing mouse ear edema model, carrageenan inducing rat voix pedis swell model and acetic acid inducing mouse experiment peritonitis model. RESULTS: The soluble protein of reSjl6 was obtained and identified by SDS-PAGE and MS. reSjl6 1.0, 5.0, 10.0 microg/kg evidently suppressed the mouse ear edema induced by dimethyl-benzene, significantly mitigated the rat voix pedis swelling induced by carrageenan, and remarkably suppressed the increase of the capillary permeability of abdominal cavity in experiment peritonitis mouse model. CONCLUSION: The results further prove that Sj16 may be a potential immunosuppressive molecule and may have a notable effect on immunomodulation.

[Results of multimodality therapy for unresectable primary liver cancer].

OBJECTIVE: To investigate the therapeutic measures for unresectable primary liver cancer (PLC). METHODS: The date of 312 unresectable primary liver cancer patients treated from January 1991 to March 2003 were retrospectively analyzed. RESULTS: Of these 312 patients, 73 were treated by cryosurgery-based combined modality therapy, 239 were treated by a TACE-oriented combined modality therapy. 289 patients except 23 were followed for a period of 2 to 156 months. The overall 1-,3- and 5-year survival rate in this series was 74. 0% , 34. 0% and 16. 7% , respectively. The 1-,3-and 5-year survival rate in the cryosurgery group was 64. 4% , 38. 4% and 27. 4% , respectively. The 1-, 3- and 5-year survival rate in the TACE group was 75. 1% , 29. 0% and 10. 0%, respectively. CONCLUSION: Treatment for the unresectable primary liver cancer should be individualized and combined with suitable therapeutic modalities.

[Treatment of prolapsed hemorrhoids with circular stapler].

OBJECTIVE: To evaluate the efficacy and safety of circumferential mucosectomy procedure for treatment of prolapsed hemorrhoids (PPH). METHODS: From June 2001 to June 2003, 74 patients (27 men and 47 women) with an average age of 57 years (ranging from 31 to 80 years), with prolapsed hemorrhoids III - IV degree underwent PPH using a circular stapler. RESULTS: 69 (93.2%) patients were fully satisfied with results. Two patients underwent simultaneous rectal polypectomy along with PPH hence required analgesic treatment for 5 days. Three patients experienced bleeding during or after operation, 1 case bleeding was due to ulcerative hemorrhoid, while the bleeding the remaining 2 cases was (bleeding about 300 ml) caused by insufficient anastomosis, thus extending operating time to 1 hour. The average operation time (70 patients) was 13 minutes (range 10 - 15 minutes). The mean hospitalization was 3.5 days (2 - 4 days), with exception of 2 patients lasting 1 week. CONCLUSION: PPH is a safe, effective and rapid method for treatment of prolapsed hemorrhoids, The procedure causes minimal pain with decreased complications.