Role of saliva proteinase 3 in dental caries

Salivary analysis can be used to assess the severity of caries. Of the known salivary proteins, a paucity of information exists concerning the role of proteinase 3 (PR3), a serine protease of the chymotrypsin family, in dental caries. Whole, unstimulated saliva was collected from children with varying degrees of active caries and tested using a Human Protease Array Kit and an enzyme-linked immunosorbent assay. A significantly decreased concentration of salivary PR3 was noted with increasing severity of dental caries (P<0.01); a positive correlation (r=0.87; P<0.01; Pearson''s correlation analysis) was also observed between salivary pH and PR3 concentration. In an antibacterial test, a PR3 concentration of 250 ng·mL⁻¹ or higher significantly inhibited Streptococcus mutans UA159 growth after 12 h of incubation (P<0.05). These studies indicate that PR3 is a salivary factor associated with the severity of dental caries, as suggested by the negative relationship between salivary PR3 concentration and the severity of caries as well as the susceptibility of S. mutans to PR3.     

CD56brightCD25+ NK cells are preferentially recruited to the maternal/fetal interface in early human pregnancy

Decidual natural killer (dNK) cells are believed to be critical for maintaining maternal/fetal tolerance and regulating placental vascular remodeling based upon their abundance and unique phenotype during early pregnancy. However, the mechanism for how the dNK cells play such important roles in successful pregnancy remains undefined. Here, we identified a subtype of dNK cells characterized as having a CD3⁻CD56^brightCD25⁺ phenotype. We found that CD56^brightCD25⁺ NK cells preferentially localize to the maternal/fetal interface during early human pregnancy. CD25⁺ dNK cells account for approximately 75% of CD25-expressing decidual immune cells (DICs). However, less than 5% of CD25-positive peripheral blood mononuclear cells are CD25⁺ NK cells. Furthermore, CD25⁺ and CD25⁻ dNK cells exhibit distinct phenotypes: CD25⁺ dNK cells display a more activated phenotype and greater cytokine-secreting capacity. Interestingly, coculture of peripheral NK (pNK) cells with primary trophoblasts upregulates the percentage of CD25-expressing pNK cells, resulting in increased expression of activation markers and cytokine production by pNK cells. In addition, we demonstrated that the CXCL12/CXCR4 axis is crucial for the recruitment of CD25⁺ dNK cells and contributes to the accumulation of CD3⁻CD56^brightCD25⁺ dNK cells at the maternal/fetal interface. Thus, our data reveal that the crosstalk between trophoblasts and pNK cells leads to the accumulation of CD3⁻CD56^brightCD25⁺ dNK cells, which exert a regulating effect at the maternal/fetal interface.     

Protective effects of lipoic acid-niacin dimers against blue light-induced oxidative damage to retinal pigment epithelium cells

AIM: To evaluate the protective effects of lipoic acid-niacin (N2L) dimers against blue light (BL)-induced oxidative damage to human retinal pigment epithelium (hRPE) cells in vitro. METHODS: hRPE cells were divided into a control group (CG), a BL group, an N2L plus BL irradiation group, an α-lipoic acid (ALA) plus BL group, an ALA-only group, and an N2L-only group. hRPE cellular viability was detected by performing 3-(4,5-dimethylthiazol-2-yl)-2,5-diphenyltetrazolium (MTT) bromide assays, and apoptosis was evaluated by annexin-V-PE/7-AAD staining followed by flow cytometry. Ultrastructural changes in subcellular organelles were observed by transmission electron microscopy. Reactive oxygen species formation was assayed by flow cytometry. The expression levels of the apoptosis-related proteins BCL-2 associated X protein (BAX), B-cell leukmia/lymphoma 2 (BCL-2), and caspase-3 were quantified by Western blot analysis. RESULTS: BL exposure with a light density of 4±0.5 mW/cm2 exceeding 6h caused hRPE toxicity, whereas treatment with a high dose of N2L (100 mol/L) or ALA (150 mol/L) maintained cell viability at control levels. BL exposure caused vacuole-like degeneration, mitochondrial swelling, and reduced microvillus formation; however, a high dose of N2L or ALA maintained the ultrastructure of hRPE cells and their organelles. High doses of N2L and ALA also protected hRPE cells from BL-induced apoptosis, which was confirmed by Western blot analysis: BCL-2 expression significantly increased, while BAX and caspase-3 expression slightly decreased compared to the CG. CONCLUSION: High-dose N2L treatment (>100 mol/L) can reduce oxidative damage in degenerating hRPE cells exposed to BL with an efficacy similar to ALA.     

Protection of tight junction between RPE cells with tissue factor targeting peptide

AIM: To investigate the effect of tissue factor targeting peptide (TF-TP) on retinal pigment epithelium (RPE) cells tight junctions. METHODS: Cell counting kit-8 (CCK-8) was used to measure the proliferation of ARPE-19 cells. Expression of tight junction, ZO-1 in ARPE-19 cells was measured by Western blot and immunofluorescent staining. Western blot was also used to detect the expression of tissue factor (TF). CEC Transmigration Assay was used to measure the migration of ARPE-19 cells. The transport of fluorescent markers [fluorescein isothiocyanate dextrans of 4, 10, 20 (FD4, FD10, FD20)] and the transepithelial electrical resistance (TEER) were used to measure in ARPE-19 cell. RESULTS: CCK-8 assay showed that 5 μmol/L TF-TP can inhibit ARPE-19 cells abnormally proliferation stimulated by lipopolysaccharide (LPS; P<0.05). LPS increased the transport of fluorescent markers (FD4, FD10, FD20) and decreased TEER levels in ARPE-19 cells, respectively, which were prevented by 5 μmol/L TF-TP pretreatment (P<0.05). Furthermore, LPS significantly up-regulated the expression of TF and downregulated the expression of ZO-1 (P<0.05) in ARPE-19 cell which was inhibited by the TF-TP (P<0.05). In addition, TF-TP inhibited the abnormal migration induced by LPS in ARPE-19 cell (P<0.05). CONCLUSION: Our findings suggest that TF-TP suppressed proliferation and migration of ARPE-19 cells induced by LPS, and maintained the RPE tight junctions through inhibition of TF expression and increased expression of ZO-1.