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.

Identification of specific marker proteins in cells is useful for isolating cells and determining their cellular characteristics and functions. Based on our previous study showing that matrix metalloproteinase 9 (MMP-9) can be used as a marker for porcine spermatogonia, the expression pattern of MMP-9 was determined in both pre- (5-month old) and post-pubertal (11–month old) bovine testes. Histological analysis revealed that spermatogonia were located near the basement membrane in both testes, while spermatozoa were not detected in the 5-month old pre-pubertal bovine testes and epididymides. Mature spermatozoa were observed in the 11-month bovine testes and epididymides, and MMP-9 expression in 11-month old bovine testes was lower than 5-month old testes, according to reverse transcription-PCR and real-time-PCR data. To determine the specific expression sites of MMP-9 in the bovine testes, immunohistochemistry was performed. Expression of MMP-9 was observed in cells near the basement membrane of seminiferous tubules in both 5- and 11-month old testes. Furthermore, MMP-9 positive cells expressed protein gene product 9.5 (PGP9.5) and deleted in azoospermia (DAZL) that are already known as bovine spermatogonial stem cells markers. In the present study, MMP-9 expression was identified in both pre- and post-pubertal bovine spermatogonia expressing PGP9.5 and DAZL, and located near the basement membrane of seminiferous tubules. Thus, MMP-9 can be used as a marker for bovine spermatogonia, and may provide useful platforms for understanding the interaction between germ cells and extracellular matrix during spermatogenesis in the seminiferous tubules.

Pleomorphic adenoma (PA) is the most common benign salivary gland tumor. It is biphasic and is characterized by an admixture of epithelial and spindle-shaped myoepithelial cells in a variable background stroma. Epithelial-myoepithelial carcinoma (EMC) is a malignant biphasic salivary gland tumor typically composed of clear myoepithelial cells that surround epithelial-lined ducts resembling intercalated ducts. The differential diagnosis between the two tumor may be occasionally encountered because of the shared histophatologic feature. And then, it would be more reliable to differentiate the tumors based on biological behavior such as the expression of distinct intermediate filaments such as cytokeratin, invasiveness- related molecules, and the growth factor receptor to aberrantly facilitate the tumor growth, and the growth fraction of tumors. Therefore, from the 10 cases of PA and 6 cases of EMC, we immunohistochemically examined the differential expression of the cytokine 7 and 14, matrix metalloproteinase-9, C-KIT, and Ki-67 between the two tumor. At the results, there were significant differences of CK7 expression in non-luminal cells (P = 0.000) and CK14 expression in luminal and non-luminal cells of the both tumors (P = 0.025 and P = 0.000, respectively). In the comparison of the biologic behavior, a significantly increased expression of MMP-9, C-KIT and Ki-67 was found in the cases of EMC when compared to those of PA (P = 0.043, P = 0.011, and P = 0.000, respectively). In conclusion, the differences of CK expression in luminal and non-luminal cells between PA and EMC seem to reflect the difference of the origin and the level of the maturation of the tumor cell. Increased expression of MMP-9, C-KIT, and Ki-67 in EMC may represent more aggressive biologic behavior of the tumor compared with benign salivary tumor such as PA. Our results may be helpful to understand the histiogenesis of the two tumors and the difference of biologic behavior and to differentiate them when the limited specimen was submitted. Further study of many more cases of EMC is needed to validate the usefulness of these molecules as the diagnostic aid.