Periostin Mediates Condylar Resorption via the NF-κB-ADAMTS5 Pathway.

Although the up-regulation of periostin in osteoarthritic (OA) is found, its function on OA condyle caused by disc displacement is not clear. Our objective was to explore whether periostin has any effect on condylar resorption. We initially identified periostin-positive cells in temporomandibular joint osteoarthritic (TMJ-OA) cartilage. Furthermore, the vitro analysis confirmed that the expression of periostin in chondrocytes treated with a static pressure of 150 kpa and 200 kpa for 3 h by an in-house-designed pressure chamber. To explore the underlying mechanism, we found that periostin can induce IκBα phosphorylation and its subsequent degradation, leading to consequent p65 nuclear translocation and subsequent induction of ADAMTS5 expression, which is known to be detrimental to cartilage extracellular matrix production. Importantly, inhibiting NF-κB signaling, by BAY 11-7082 treatment, rescued periostin-induced ADAMTS5 up-regulation. This study elucidated the direct role of periostin in condylar resorption, which was found to occur via NF-κB-ADAMTS5 signaling. Inhibition of this pathway might provide a new strategy for TMJ-OA treatment.

Characterization of recombinant Streptococcus mitis-derived human platelet aggregation factor.

We previously purified Streptococcus mitis-derived human platelet aggregation factor (Sm-hPAF) from the culture supernatant of S. mitis strain Nm-65, isolated from the tooth surface of a patient with Kawasaki disease. Here we produced recombinant Sm-hPAF protein (rSm-hPAF) in Escherichia coli, to determine whether rSm-hPAF conserves its platelet aggregation activity. rSm-hPAF precursor (665 amino acids) shows up to 36-56% identity with the family of cholesterol-dependent cytolysins (CDCs), and rSm-hPAF displayed potent hemolytic activity toward mammalian erythrocytes, including human erythrocytes with platelet aggregation activity. The 162-amino acid amino-terminal domain of rSm-hPAF was found in no other CDCs except lectinolysin; this domain is homologous to a portion of pneumococcal fucolectin-related protein. Interestingly, suilysin (SLY) and pneumolysin (PLY) of CDCs also exhibit substantial human platelet aggregation activity, similar to rSm-hPAF, and the platelet aggregation by rSm-hPAF, SLY, and PLY was morphologically confirmed using light and electron microscopy.

Vaccination with Ep-CAM protein or anti-idiotypic antibody induces Th1-biased response against MHC class I- and II-restricted Ep-CAM epitopes in colorectal carcinoma patients.

PURPOSE: The tumor-associated antigen Ep-CAM (epithelial cell adhesion molecule) is overexpressed in colorectal carcinoma (CRC). The aim of the present study was to evaluate and compare the safety and immunogenicity of a recombinant Ep-CAM protein and a human anti-idiotypic antibody (anti-Id) mimicking Ep-CAM. EXPERIMENTAL DESIGN: Patients with resected American Joint Committee on Cancer stages II-IV CRC without remaining macroscopic disease received intradermal/subcutaneous injections of Ep-CAM (400 microg/dose; n = 7) or anti-Id (500 microg/dose; n = 6) at weeks 0, 2, and 6 in combination with granulocyte macrophage colony-stimulating factor (75 microg/day, for 4 consecutive days). RESULTS: Adverse reactions were mild (grade I-II). All patients immunized with the Ep-CAM protein produced Ep-CAM-specific IgG antibodies, predominantly IgG1 and IgG3 subclasses, whereas no humoral response was induced by the anti-Id vaccine. All patients, with one exception in each group, mounted an Ep-CAM-specific proliferative T-cell response. The immune response was more rapid, potent, and protracted after Ep-CAM in comparison with anti-Id vaccination. Interferon-gamma-secreting cells (ELISPOT) were detected in both immunization groups against the Ep-CAM protein as well as various Ep-CAM-derived MHC class I- and II-restricted peptides. Flow cytometry analysis showed that Ep-CAM-specific interferon-gamma- and perforin-producing cells predominantly resided within CD8(+)CD56- and CD8(dim)CD56+ T cells. CONCLUSIONS: Ep-CAM protein in combination with granulocyte macrophage colony-stimulating factor induced a long-lasting, Th1-biased humoral and cellular immune response compared with anti-Id. Ep-CAM-specific T cells and natural killer-like T cells responding in a MHC class I- and II-restricted manner were also induced. Vaccination with Ep-CAM protein may warrant further investigation as a novel therapeutic approach to CRC.

Interactions of leukocyte integrins with intercellular adhesion molecule 1 in the production of inflammatory vascular injury in vivo. The Shwartzman reaction revisited.

We have investigated the role of leukocyte-endothelial cell interactions in a rabbit model of hemorrhagic vasculitis. Microvascular injury was produced in the skin by intradermal injection of Salmonella typhosa endotoxin followed 20 h later by intravenous zymosan, which activates complement. Hemorrhagic necrosis develops in the "prepared" skin sites which is characterized by microthrombi, neutrophil aggregation, platelet and fibrin deposition, and massive extravasation of erythrocytes. Hemorrhage in these Shwartzman-like lesions was quantitated by 99mTc-labeled autologous erythrocytes. Inhibition of the hemorrhagic response was obtained with mAb reactive with ICAM-1 as well as mAb against the leukocyte CD18 when either was administered intravenously just before intravenous zymosan challenge. This observation suggests that an intravascular event occurring in response to complement activation is required for the development of hemorrhagic vasculitis. We hypothesize that agents which successfully prepare the skin for the Shwartzman response after their intradermal injection do so by promoting increased intercellular adhesion molecule 1 (ICAM-1) expression on the vascular endothelium. Activation of complement then induces CD11/CD18 expression on circulating leukocytes thus producing an intravascular CD11/CD18-ICAM-1 (leukocyte-endothelium) adhesion event. Inhibition of intravascular leukocyte-leukocyte aggregation with mAb against CD11b (Mac-1) showed partial inhibition of hemorrhage, while mAb against CD11a (LFA-1) showed no inhibitory activity. This type of cytokine-primed, neutrophil-dependent vascular damage may be a model of human vasculitic processes where microvascular damage is produced in the absence of immune-complex deposition.