The role of complement C5a receptor in DPSC odontoblastic differentiation and in vivo reparative dentin formation / 国际口腔科学杂志·英文版

Therapeutic dentin regeneration remains difficult to achieve, and a majority of the attention has been given to anabolic strategies to promote dentinogenesis directly, whereas, the available literature is insufficient to understand the role of inflammation and inflammatory complement system on dentinogenesis. The aim of this study is to determine the role of complement C5a receptor (C5aR) in regulating dental pulp stem cells (DPSCs) differentiation and in vivo dentin regeneration. Human DPSCs were subjected to odontogenic differentiation in osteogenic media treated with the C5aR agonist and C5aR antagonist. In vivo dentin formation was evaluated using the dentin injury/pulp-capping model of the C5a-deficient and wild-type mice. In vitro results demonstrate that C5aR inhibition caused a substantial reduction in odontogenic DPSCs differentiation markers such as DMP-1 and DSPP, while the C5aR activation increased these key odontogenic genes compared to control. A reparative dentin formation using the C5a-deficient mice shows that dentin regeneration is significantly reduced in the C5a-deficient mice. These data suggest a positive role of C5aR in the odontogenic DPSCs differentiation and tertiary/reparative dentin formation. This study addresses a novel regulatory pathway and a therapeutic approach for improving the efficiency of dentin regeneration in affected teeth.

Yersinia enterocolitica Exploits Signal Crosstalk between Complement 5a Receptor and Toll-like Receptor 1/2 and 4 to Avoid the Bacterial Clearance in M cells

In the intestinal mucosal surface, microfold cells (M cells) are the representative gateway for the uptake of luminal antigens. At the same time, M cells are the primary infection site for pathogens invading mucosal surface for their infection. Although it is well recognized that many mucosal pathogens exploit the M cells for their infection, the mechanism to infect M cells utilized by pathogens is not clearly understood yet. In this study, we found that M cells expressing complement 5a (C5a) receptor (C5aR) also express Toll-like receptor (TLR) 1/2 and TLR4. Infection of Yersinia enterocolitica, an M cell-invading pathogen, synergistically regulated cyclic adenosine monophosphate-dependent protein kinase A (cAMP-PKA) signaling which are involved in signal crosstalk between C5aR and TLRs. In addition, Y. enterocolitica infection into M cells was enhanced by C5a treatment and this enhancement was abrogated by C5a antagonist treatment. Finally, Y. enterocolitica infection into M cells was unsuccessful in C5aR knock-out mice. Collectively, we suggest that exploit the crosstalk between C5aR and TLR signaling is one of infection mechanisms utilized by mucosal pathogens to infect M cells.

Expression of C3aR and C5aR in trichloroethylene-sensitized mouse liver / 中华劳动卫生职业病杂志

<p><b>OBJECTIVE</b>To study the expression of C3aR and C5aR in trichloroethylene-sensitized mouse liver injury and discuss the pathogenesis of Dermatitis Medicamentosa-like of TCE (DMLT).</p><p><b>METHODS</b>6∼8 w female BALB/c mouse were randomly divided into blank control group, solvent control group and TCE treatment group. TCE was given to the mouse for sensitization at 1th, 4th, 7th, 10th day and challenge at 17th day and 19th day. Before killing mouse, liver weight and body weight were recorded. The livers were separated at 24 h, 48 h, 72 h and 7 d after challenge. And the liver sections were used for immunofluorescence stain and RT-PCR to detect the expression levels of C3aR and C5aR.</p><p><b>RESULTS</b>Microscopic examination showed no significant change in liver structure or organization in TCE non-sensitized group, while liver cell oedema, cell necrosis and inflammatory cell infiltration were clearly observed in TCE-sensitized groups. The expression levels of C3aR and C5aR in 24 h, 48 h, 72 h and 7 d TCE-sensitized groups were significant higher than blank control group, solvent control group and related TCE non-sensitized groups (P < 0.05).</p><p><b>CONCLUSION</b>Complement activation was involved in TCE-induced liver injury and C3aR and C5aR might play essential role in the process.</p>

Mucosal Immune System and M Cell-targeting Strategies for Oral Mucosal Vaccination

Vaccination is one of the most effective methods available to prevent infectious diseases. Mucosa, which are exposed to heavy loads of commensal and pathogenic microorganisms, are one of the first areas where infections are established, and therefore have frontline status in immunity, making mucosa ideal sites for vaccine application. Moreover, vaccination through the mucosal immune system could induce effective systemic immune responses together with mucosal immunity in contrast to parenteral vaccination, which is a poor inducer of effective immunity at mucosal surfaces. Among mucosal vaccines, oral mucosal vaccines have the advantages of ease and low cost of vaccine administration. The oral mucosal immune system, however, is generally recognized as poorly immunogenic due to the frequent induction of tolerance against orally-introduced antigens. Consequently, a prerequisite for successful mucosal vaccination is that the orally introduced antigen should be transported across the mucosal surface into the mucosa-associated lymphoid tissue (MALT). In particular, M cells are responsible for antigen uptake into MALT, and the rapid and effective transcytotic activity of M cells makes them an attractive target for mucosal vaccine delivery, although simple transport of the antigen into M cells does not guarantee the induction of specific immune responses. Consequently, development of mucosal vaccine adjuvants based on an understanding of the biology of M cells has attracted much research interest. Here, we review the characteristics of the oral mucosal immune system and delineate strategies to design effective oral mucosal vaccines with an emphasis on mucosal vaccine adjuvants.

Effect of C5-siRNA silencing receptor C5 on myocardial ischemia injury in rats / 南方医科大学学报

<p><b>OBJECTIVE</b>To study the effect of C5-siRNA on pathological changes after myocardial ischemia in rats.</p><p><b>METHODS</b>Thirty healthy Sprague-Dawley rats were randomly divided into sham-operated group, ischemia group and C5-siRNA group. The cardiac ischemia models were established in ischemia group and C5-siRNA group by ligating the proximal end of the left anterior descending (LAD) coronary artery. The rats were infused with 100 microl/kg of C5-siRNA into myocardial tissue in C5-siRNA group and equal amount of normal saline in ischemia group and sham-operated group after ligating the LAD coronary artery for 30 min and then performed of ischemia for 4 hours. The cardiac index and left ventricular mass index were determined, morphological changes of myocardial tissue observed under optical microscope and the expression of C5 was detected by immunohistochemical staining and image analysis system.</p><p><b>RESULTS</b>There were no statistically significant difference between the three groups in the left ventricular mass index and cardiac index in the rats after ischemia for 4 hours. Light microscopy indicated edema and degeneration of the myocardial tissue were milder in C5-siRNA group than in ischemia group, a small amount of red blood cells existed in the myocardial stroma of the former. The expression of C5 was increased more significantly in ischemia group and C5-siRNA group than in sham-operated group (P<0.001), but was decreased in C5-siRNA group more than in ischemia group with no statistically significant difference between the two groups (P=0.132).</p><p><b>CONCLUSION</b>C5-siRNA could attenuate myocardial ischemia injury in rats by reducing inflammatory cell infiltration and expression of C5.</p>

Regulation of tyrosylprotein sulfotransferases activity by sulfotyrosine / 中国医学科学院学报

<p><b>OBJECTIVE</b>To investigate the role of sulfated tyrosine in regulating the activity of tyrosylprotein sulfotransferases (TPST) 1 and TPST2.</p><p><b>METHODS</b>Constructs of TPST 1 and TPST2 were amplified by polymerase chain reaction (PCR), then fused into immunoglobulin G1 Fc region. All the variants in which sulfated tyrosines were mutated to phenylalanine were made by the PCR-based Quick Change method and confirmed by sequencing the entire reading frame. Small hairpin RNA (shRNA) constructs-targeting nucleotides 259-275 of TPST1 and nucleotides 73-94 of TPST2 were generated and subcloned into pBluescript. Human embryonic kidney (HEK) 293T cells were transfected with these plasmids. One day later, cells were split: one part was labeled with 35S-cysteine and methionine or 35S-Na2SO3 overnight, the second part was used for 125I labeled binding experiment, and the third part was retained for binding and flow cytometry.</p><p><b>RESULTS</b>Tyrosines at position 326 of TPST1 and position 325 of TPST2 were sulfated posttranslationally. Tyrosine sulfation of TPSTs was effectively inhibited by sulfation inhibitors, including specific shRNAs and non-specific NaCIO3. shRNAs reduced the sulfation of C3a receptor and C5a receptor, and partially blocked the binding of these two receptors to their respective ligands.</p><p><b>CONCLUSIONS</b>The activities of TPSTs were regulated by tyrosine sulfation. Inhibition of sulfotyrosine decreases the binding ability of C3a receptor and C5a receptor to their respective ligands.</p>

Expression of C5aR (CD88) of synoviocytes isolated from patients with rheumatoid arthritis and osteoarthritis / 中华医学杂志(英文版)

<p><b>OBJECTIVE</b>To investigate the expression of anaphylatoxin receptor C5aR (CD88) in synoviocytes from patients with rheumatoid arthritis (RA) and osteoarthritis (OA).</p><p><b>METHODS</b>The expression of C5aR was assessed in synoviocytes isolated from 27 RA and 12 OA patients using reverse transcription-polymerase chain reactions (RT-PCR), flow cytometry, and immunofluorescence analysis. The effects of C5a on the release of tumor necrosis factor alpha (TNF alpha) from synoviocytes were assayed using enzyme-linked immunosorbent assays (ELISA).</p><p><b>RESULTS</b>C5aR mRNA was detected in 24 of 27 samples from RA patients, and 10 of 12 samples from OA patients. Flow cytometric analysis and immunofluorescence study demonstrated the cell surface expression of C5aR in a significant proportion of synoviocytes from both RA and OA patients, and the level of C5aR expression in synoviocytes was significantly correlated with joint swelling, erythrocyte sedimentation rate (ESR) and C-reactive protein (CRP) in RA patients. Finally, interaction of C5aR with its ligand C5a was shown to enhance lipopolysaccharide (LPS)-induced TNF alpha release from synoviocytes.</p><p><b>CONCLUSIONS</b>The expression of C5aR in synoviocytes from inflammatory joint diseases and also the induction of TNF alpha release in activated synoviocytes by the interaction of C5a and C5aR suggest that the C5a/C5aR system may play an important role in joint inflammation process.</p>

The role of C5a in adhesion properties of polymorphonuclear leukocyte to pulmonary vascular endothelial cells in burn patients with acute lung injury / 中华烧伤杂志

<p><b>OBJECTIVE</b>To explore the postburn adhesion properties of polymorphonuclear leukocyte (PMN) onto pulmonary vascular endothelial cells (PVEC) in burn patients with acute lung injury (ALI), so as to determine the role of C5a on PVEC-PMN adhesion.</p><p><b>METHODS</b>Microtubule sucking technique was employed to determine the PVEC-PMN adhesion. The myeloperoxidase (MPO) was also assayed to reflect the magnitude of PVEC-PMN adhesion.</p><p><b>RESULTS</b>The magnitude of PVEC-PMN adhesion increased and the adhesion force increased along with an increase in rh-C5a concentration. Simultaneously, the MPO activity was increased, which could be inhibited by anti-C5aR McAb in a concentration 1:104.</p><p><b>CONCLUSION</b>Both C5a and C5aR participated in PVEC-PMN adhesion, which might be important in the pathogenesis of ALI.</p>