α4-laminins, such as laminins 411 and 421, are mesenchymal laminins expressed by blood and lymphatic vessels and some tumor cells. Laminin-411 promotes migration of leukocytes and endothelial cells, but the effect of this laminin and laminin-421 on tumor cells is poorly understood. In the present study, we demonstrate that laminin-411 and, to a greater extent, laminin-421 significantly promote migration of tumor cells originated from melanomas, gliomas and different carcinomas via α6β1 integrin. In solid-phase binding assays, both laminins similarly bound α6β1 integrin but only laminin-421, among several laminin isoforms, readily bound MCAM (CD146), a cell-surface adhesion molecule strongly associated with tumor progression. Accordingly, a function-blocking mAb to MCAM inhibited tumor cell migration on laminin-421 but not on laminins 411 or 521. In tumor tissues, melanoma cells co-expressed MCAM, laminin α4, β1, β2 and γ1 chains, and integrin α6 and β1 chains. The present data highlight the novel role of α4-laminins in tumor cell migration and identify laminin-421 as a primary ligand for MCAM and a putative mediator of tumor invasion and metastasis.

The oral mucosa exhibits unique regenerative properties, sometimes referred to as foetal-like wound healing. Researchers from our institute have used sheets of oral mucosa epithelial cells (OMECs) for regenerative medicine applications including cornea replacement and oesophageal epithelial regeneration for stricture prevention. Here, we have isolated exosomes from clinical-grade production of OMEC sheets from healthy human donors (n = 8), aiming to evaluate the clinical potential of the exosomes to stimulate epithelial regeneration and to improve understanding of the mode-of-action of the cells. Exosomes were isolated from conditioned (cExo) and non-conditioned (ncExo) media. Characterization was performed using Western blot for common exosomal-markers: CD9 and flotillin were positive while annexin V, EpCam and contaminating marker GRP94 were negative. Nanoparticle tracking analysis revealed a diameter of ~120 nm and transmission electron microscopy showed a corresponding size and spherical appearance. Human skin fibroblasts exposed to exosomes showed dose-dependent reduction of proliferation and a considerable increase of growth factor gene expression (HGF, VEGFA, FGF2 and CTGF). The results were similar for both groups, but with a trend towards a larger effect from cExo. To study adhesion, fluorescently labelled exosomes were topically applied to pig oesophageal wound-beds ex vivo and subsequently washed. Positive signal could be detected after as little as 1 min of adhesion, but increased adhesion time produced a stronger signal. Next, labelled exosomes were added to full-thickness skin wounds in rats and signal was detected up to 5 days after application. cExo significantly reduced the wound size at days 6 and 17. In conclusion, exosomes from OMEC sheets showed pro-regenerative effects on skin wound healing. This is the first time that the healing capacity of the oral mucosa is studied from an exosome perspective. These findings might lead to a combinational therapy of cell sheets and exosomes for future patients with early oesophageal cancer.

Gut microbiota play many important roles, such as the regulation of immunity and barrier function in the intestine, and are crucial for maintaining homeostasis in living organisms. The disruption in microbiota is called dysbiosis, which has been associated with various chronic inflammatory conditions, food allergies, colorectal cancer, etc. The gut microbiota is also affected by several other factors such as diet, antibiotics and other medications, or bacterial and viral infections. Moreover, there are some reports on the oral-gut-liver axis indicating that the disruption of oral microbiota affects the intestinal biota. Non-alcoholic fatty liver disease (NAFLD) is one of the systemic diseases caused due to the dysregulation of the oral-gut-liver axis. NAFLD is the most common liver disease reported in the developed countries. It includes liver damage ranging from simple steatosis to nonalcoholic steatohepatitis (NASH), cirrhosis, and cancer. Recently, accumulating evidence supports an association between NAFLD and dysbiosis of oral and gut microbiota. Periodontopathic bacteria, especially Porphyromonas gingivalis, have been correlated with the pathogenesis and development of NAFLD based on the clinical and basic research, and immunology. P. gingivalis was detected in the liver, and lipopolysaccharide from this bacteria has been shown to be involved in the progression of NAFLD, thereby indicating a direct role of P. gingivalis in NAFLD. Moreover, P. gingivalis induces dysbiosis of gut microbiota, which promotes the progression of NAFLD, through disrupting both metabolic and immunologic pathways. Here, we review the roles of microbial dysbiosis in NAFLD. Focusing on P. gingivalis, we evaluate and summarize the most recent advances in our understanding of the relationship between oral-gut microbiome symbiosis and the pathogenesis and progression of non-alcoholic fatty liver disease, as well as discuss novel strategies targeting both P. gingivalis and microbial dysbiosis.

Dipeptidyl peptidase (DPP) 4, DPP5, DPP7 and DPP11, expressed in the periplasmic space, are crucial for energy production for Porphyromonas gingivalis, an asaccharolytic bacterium that causes periodontal disease. Bacterial DPP4 seems to be involved in regulation of blood glucose level via degradation of incretins. The present study aimed to identify four dpp orthologs in oral microbiota by database searches, and their enzymatic activities in periodontopathic and cariogenic bacteria, as well as oral specimens were determined. Search in the databases suggested that 43 species of 772 taxa possess dpp4 and other dpp genes. Most species are in the genera Bacteroides, Capnocytophaga, Porphyromonas, Prevotella and Tannerella, indicating a limited distribution of dpp orthologs in anaerobic periodontopathic rods. In accordance with those results, activities of all four DPPs were demonstrated in P. gingivalis, Porphyromonas endodontalis and Tannerella forsythia, while they were negligible in Treponema denticola, Fusobacterium nucleatum and Aggregatibacter actinomycetemcomitans. Furthermore, DPP activities were also detected in subgingival dental plaque at different intensities among individual specimens, while DPP4 activity presumably derived from human entity was solely predominant in saliva samples. These findings demonstrated that DPP activities in dental plaque serve as potent biomarkers to indicate the presence of periodontopathic bacteria.

Although Streptococcus anginosus constitutes a proportion of the normal flora of the gastrointestinal and genital tracts, and the oral cavity, it has been reported that S. anginosus infection could be closely associated with abscesses at various body sites, infective endocarditis, and upper gastrointestinal cancers. The colonization in an acidic environment due to the aciduricity of S. anginosus could be the etiology of the systemic infection of the bacteria. To elucidate the aciduricity and acid tolerance mechanisms of the microbe, we examined the viability and growth of S. anginosus under acidic conditions. The viabilities of S. anginosus NCTC 10713 and Streptococcus mutans ATCC 25175 at pH 4.0 showed as being markedly higher than those of Streptococcus sanguinis ATCC 10556, Streptococcus gordonii ATCC 10558, and Streptococcus mitis ATCC 49456; however, the viability was partially inhibited by dicyclohexylcarbodiimide, an H-ATPase inhibitor, suggesting that H-ATPase could play a role in the viability of S. anginosus under acidic conditions. In addition, S. anginosus NCTC 10713 could grow at pH 5.0 and showed a marked arginine deiminase (ADI) activity, unlike its ΔarcA mutant, deficient in the gene encoding ADI, and other streptococcal species, which indicated that ADI could also be associated with aciduricity. These results suggest that S. anginosus has significant aciduric properties, which can be attributed to these enzyme activities.