Periodontal diseases have been associated with the development of cardiovascular diseases. Accumulating evidences have indicated that Porphyromonas gingivalis , a major periodontopathic pathogen, plays a critical role in the pathogenesis of atherosclerosis. In the present study, we demonstrated that P. gingivalis lipopolysaccharide (LPS) increases the mRNA and protein expression of matrix metalloproteinase-9 (MMP-9) in rat vascular smooth muscle cells. We showed that the MMP-9 expression induced by P. gingivalis LPS is mediated by the activation of signal transducer and activator of transcription 3 (STAT3) in vascular smooth muscle cells. Furthermore, the inhibition of STAT3 activity reduced P. gingivalis LPS-induced migration of vascular smooth muscle cells. Overall, our findings indicate that P. gingivalis LPS stimulates the migration of vascular smooth muscle cells via STAT3-mediated MMP-9 expression.

The T-cell receptor (TCR) engages with an antigen and initiates a signaling cascade that leads to the activation of transcription factors. Roquin, a protein encoded by the RC- 3H1 gene and characterized as an immune regulator, was recently identified as a novel RING-type ubiquitin ligase family member, but the mechanisms by which Roquin regulates T-cell responses are unclear. We used the EL-4 murine lymphoma cell line to elucidate the role of Roquin in vitro. Roquin-overexpressing EL-4 cells became hyper-responsive after anti-CD3/CD28 stimulation in vitro and were a major source of the cytokines IL-2 and TNF-α. Upon activation, these cells showed particularly enhanced production of IL-2 and TNF-α. To clarify the important role played by Roquin in T-cell responses ex vivo, we generated T-cell-specific Roquin transgenic (Tg) mice. Roquin-Tg CD4+ T-cells showed enhanced production of IL-2 and TNF-α in response to TCR stimulation with anti-CD28 co-stimulation. Further studies are necessary to investigate the role of Roquin in the regulation of primary T-cell activation, survival, and differentiation.

Several types of white blood cells, such as T cells, B cells, and macrophages, are involved in the immune response. In particular, the processes of T-cell activation play a crucial role in an adaptive immune response, whereby the T-cell receptor (TCR) engages with an antigen and signals a cascade that leads to the activation of transcription factors (AP-1, NF-κB, and NFAT) that are critically involved in cytokine production. Roquin, encoded by the RC3H1 gene and characterized as an immune regulator, was recently identified as a novel RING-type ubiquitin ligase family member, but the mechanisms by which Roquin proteins regulate T-cell responses are unclear. To elucidate the role of Roquin in vitro, murine lymphoma EL-4 cells were used. Roquin overexpressing Tcells became hyper-responsive upon anti-CD3/CD28 stimulation in vitro and were a major source of cytokines such as IL-2, TNF-α, IL-6, and IL-10. Upon activation, these cells showed preferentially enhanced production of IL-2 and TNF-α, but not IFN-γ. To clarify the important role of Roquin in the T-cell response ex vivo, we generated T-cell-specific Roquin-transgenic (Tg) mice having a higher expression of Roquin in T cells as compared to wild-type mice. Using Roquin-Tg mice, we studied whether immune responses are affected ex vivo. Roquin-Tg CD4+ T cells showed enhanced production of IL-2 or TNF-α to TCR stimulation with anti-CD28 costimulation via up-regulation of CD28. T-cell proliferation also increased in Roquin-Tg CD4+ T cells after anti-CD3/CD28 treatment. Further studies on the role of Roquin in the regulation of primary T-cell activation, survival, and differentiation may be anticipated.

Tumor necrosis factor-related apoptosis inducing ligand (TRAIL) is a well-known inducer of apoptotic cell death in many tumor cells. 1RAIL is expressed in human placenta, and cytotrophoblast cells express 1RAIL receptors. However, the role of TRAIL in human placentas and cytotrophoblast cells is not. well understood. In this study a trophoblast cell line, JEG-3, was used as a model system to examine the effect of TRAIL. on key intracellular signaling pathways involved in the control of trophoblastic cell apoptosis and survival JEG-3 cells expressed receptors for 1RAIL, death receptor (DR) 4, DR5, decoy receptor (OcR) 1 and DeR2. Recombinant human TRAIL (rhTRAIL) did not have a cytotoxic effect determined by MIT assay and did not induce apoptotic cell death determined by poly-(ADP-ribose) polymerase cleavage assay. rhTRAIL induced a rapid and transient nuclear translocation of nuclear factor-kB(NF-kB) determined by immunoblotting using nuclear protein extracts. rhTRAIL rapidly activated extracellular signal-regulated protein kinase (ERK) 1/2 as determined by immnoblotting for phospho-ERK1/2. However, c-Jun N-terminal kinase (JNK), p38 mitogen-activated protein kinase (p38MAPK) and Akt (protein kinase B) were not activated by rhTRAIL. The ability of 1RAIL to induce NF-kB and ERK1/2 suggests that interaction between TRAIL and its receptors may play an important role in trophoblast cell function during pregnancy.