Analysis of senescence in gingival tissues and gingival fibroblast cultures.

OBJECTIVE: To determine senescence-associated changes in the gingival tissues of aged mice and gingival fibroblast cultures. MATERIALS AND METHODS: The production of senescence-associated ß-galactosidase (SA-ß-gal) and mRNA expression of p16, p21, interleukin (IL)-1ß, and tumor necrosis factor α (TNF-α) were evaluated in gingival tissues, gingival fibroblasts of 10- and 20-month-old C57BL/6NCrl mice, and multiple-passaged and hydrogen peroxide-stimulated human gingival fibroblasts (HGFs). Changes in molecular expression in HGF cultures due to senescent cell elimination by the senolytic drug ABT-263 (Navitoclax) were analyzed. RESULTS: Compared to 10-week-old mice, the 20-month-old mice had higher numbers of M1 macrophages. The proportion of cells expressing SA-ß-gal were also higher in 20- month-old mice than in 10-week-old-mice. Gingival fibroblasts in 20-month-old mice expressed less collagen 1a1, collagen 4a1, and collagen 4a2 mRNA than those in 10-week-old mice. Compared to control cells, H2O2 treated HGF cells expressed higher levels of SA-ß-gal and p16, p21, IL-1ß, and TNF-α. Furthermore, ABT-263 suppressed HGF cell expression of cytokines after senescence induction. CONCLUSIONS: Senescence-associated changes were observed in the gingival tissues of aged mice and HGF cultures. In addition, the potential of senolytic drugs to modify aging-related changes in the gingiva was shown.

Analgesic Mechanisms of Steroid Ointment against Oral Ulcerative Mucositis in a Rat Model.

Despite the long history of use of steroid ointments for oral mucositis, the analgesic mechanism has not been fully elucidated. In this study, we examined the effects of triamcinolone acetonide (Tmc) on oral ulcerative mucositis-induced pain in conscious rats by our proprietary assay system. Based on evaluations of the physical properties and retention periods in the oral mucosa of human volunteers and rats, we selected TRAFUL® ointment as a long-lasting base. In oral ulcerative mucositis model rats, TRAFUL® with Tmc suppressed cyclooxygenase-dependent inflammatory responses with upregulations of glucocorticoid receptor-induced anti-inflammatory genes and inhibited spontaneous nociceptive behavior. When an ointment with a shorter residual period was used, the effects of Tmc were not elicited or were induced to a lesser extent. Importantly, TRAFUL® with Tmc also improved oral ulcerative mucositis-induced mechanical allodynia, which has been reported to be independent of cyclooxygenase. Ca2+ imaging in dissociated trigeminal ganglion neurons showed that long-term preincubation with Tmc inhibited the hypertonic stimulation-induced Ca2+ response. These results suggest that the representative steroid Tmc suppresses oral ulcerative mucositis-induced pain by general anti-inflammatory actions and inhibits mechanical sensitivity in peripheral nerves. For drug delivery, long-lasting ointments such as TRAFUL® are needed to sufficiently induce the therapeutic effects.

Tuning the Reactivity of a Substrate for SNAP-Tag Expands Its Application for Recognition-Driven DNA-Protein Conjugation.

Recognition-driven modification has been emerging as a novel approach to modifying biomolecular targets of interest site-specifically and efficiently. To this end, protein modular adaptors (MAs) are the ideal reaction model for recognition-driven modification of DNA as they consist of both a sequence-specific DNA-binding domain (DBD) and a self-ligating protein-tag. Coupling DNA recognition by DBD and the chemoselective reaction of the protein tag could provide a highly efficient sequence-specific reaction. However, combining an MA consisting of a reactive protein-tag and its substrate, for example, SNAP-tag and benzyl guanine (BG), revealed rather nonselective reaction with DNA. Therefore new substrates of SNAP-tag have been designed to realize sequence-selective rapid crosslinking reactions of MAs with SNAP-tag. The reactions of substrates with SNAP-tag were verified by kinetic analyses to enable the sequence-selective crosslinking reaction of MA. The new substrate enables the distinctive orthogonality of SNAP-tag against CLIP-tag to achieve orthogonal DNA-protein crosslinking by six unique MAs.

Tranexamic Acid Improves Memory and Learning Abilities in Aging Mice.

PURPOSE: Although the onset mechanism of Alzheimer's disease, which co-occurs with aging, has been extensively studied, no effective methods that improve the decline in memory and learning abilities following aging have been developed. Tranexamic acid provided promising results for ameliorating photo-aging and extending the natural lifespan. However, it is unknown whether it affects the decline in memory and learning abilities due to aging. In this study, we examined the effect of tranexamic acid on memory and learning abilities of naturally aging mice. METHODS: ICR mice were orally administered with tranexamic acid (12 mg/kg/day) three times weekly for 2 years, and their memory and learning abilities were compared between the tranexamic acid-treated and non-treated groups. RESULTS: The decline in memory and learning abilities due to aging was ameliorated by tranexamic acid administration. The expression of plasmin and amyloid-ß decreased following the treatment with tranexamic acid. Furthermore, the number of M1-type brain macrophages diminished and that of M2 macrophages increased. In addition, administration of tranexamic acid decreased the concentrations of interleukin (IL)-1ß and tumor necrosis factor-α, while it increased the levels of IL-10 and transforming growth factor-α in the brain. CONCLUSION: These results indicated that tranexamic acid suppressed the secretion of the inflammatory cytokines aging M1-type macrophages, thereby improving age-related memory and learning abilities.

Ameliorative effect of tranexamic acid on physiological skin aging and its sex difference in mice.

An effective method to protect the skin from natural aging is unknown. Therefore, in this study, we examined the ameliorative effects of tranexamic acid on natural skin aging. In addition, we examined the sex difference in the effect exhibited by tranexamic acid. We bred hairless mice without ultraviolet ray irradiation and physical stress for 2 years. During the study period, mice were orally administered tranexamic acid (12 mg/kg/day) three times per week. Development of signs of skin aging was found to be ameliorated by tranexamic acid. Furthermore, synthetic inhibition of plasmin was observed following tranexamic acid treatment. The synthetic reinforcement of hyaluronic acid by an increase in the number of epidermal cells and the degradative inhibition of extracellular matrix (ECM) by matrix metalloproteinase (MMP) suppression were observed. These results indicate that natural skin aging was ameliorated by tranexamic acid via the regulation of the plasmin/TGF-ß/epidermal cells/hyaluronic acid and plasmin/MMPs/ECM signal transmission pathways. Taken together, sex difference was observed for the ameliorative effect of tranexamic acid on skin aging, with a stronger effect observed in females than in males. More importantly, we found that the synthesis of hyaluronic acid was stronger in female mice than in male mice.

Effect of tranexamic acid in improving the lifespan of naturally aging mice.

An effective method to improve lifespan is not known. Therefore, in this study, we examined the lifespan-extending effect of tranexamic acid in normal mice. We bred hairless mice without exposure to ultraviolet radiation and psychical stress until they died naturally. During the study period, the mice were orally administered tranexamic acid (12 mg/kg/day) three times weekly. An increase in the lifespan of mice was observed by tranexamic acid administration. Furthermore, age-related diseases of the skin were ameliorated by tranexamic acid administration. Moreover, the blood level of tumor necrosis factor-α, interleukin-6, reactive oxygen species (ROS), and matrix metalloproteinase (MMP)-9 was decreased by tranexamic acid administration. These results indicate that tranexamic acid suppresses the secretion of inflammatory cytokines, MMP-9, and ROS induced by natural aging, ameliorating age-related diseases, and, consequently, extending the lifespan.

Tranexamic Acid Ameliorates Nonmelanoma Skin Cancer Induced by Long-term Ultraviolet A Irradiation.

To date, there have been no treatments developed to ameliorate nonmelanoma skin cancer induced by long-term exposure to ultraviolet A (UVA) irradiation. In this study, we examined the effects of tranexamic acid (trans-4-aminomethyl cyclohexanecarboxylic acid) on long-term UVA-induced skin cancer. We exposed the dorsal skin of male hairless mice to UVA at a dose of 110 kJ m-2 using an FL20SBLB-A lamp three times weekly for 15 weeks after application of 7,12-dimethylbenz [a] anthracene (DMBA). During the experimental period, the mice were administered tranexamic acid (750 mg kg-1 day-1 ) three times weekly. We found that cancer development was ameliorated by administration of tranexamic acid. Furthermore, tranexamic acid treatment was observed to suppress increases in the plasma levels of matrix metalloproteinase-9 and interleukin (IL)-6, and skin expression of plasmin, CC chemokine 2, macrophages, signal transducer and activator of transcription (STAT)3, cyclin D and vascular endothelial growth factor (VEGF)-A that occurred in mice subjected to long-term UVA irradiation. These results indicated that the nonmelanoma skin cancer induced by DMBA+UVA long-term irradiation is ameliorated by tranexamic acid through regulation of the plasmin/macrophage/IL-6/STAT3/cyclin D signal transmission pathway. In addition, this ameliorative effect against skin cancer may be mediated via inhibition of the IL-6-induced expression of VEGF-A.

Tranexamic acid inhibits the plasma and non-irradiated skin markers of photoaging induced by long-term UVA eye irradiation in female mice.

Photoaging can be induced by long-term ultraviolet (UV)A eye irradiation, but an ameliorating method for such photoaging is not known. In this study, we examined the effects of tranexamic acid (trans-4-aminomethylcyclohexanecarboxylic acid) on photoaging of the skin induced by UVA eye irradiation. We used the C57BL/6 j female mice and locally exposed their eyes to UVA at a dose of 110 kJ/m2 using an FL20SBLB-A lamp multiple times a week for one year. The plasma urocortin 2, ß-endorphin, methionine enkephalin (OGF), and histamine content, as well as the expression of the corticotropin-releasing hormone receptor (CRHR) type 2, µ-opioid receptor, opioid growth factor receptor (OGFR), T-bet, and GATA3 increased in the mice subjected to UVA eye irradiation. However, the increased levels of urocortin 2, methionine enkephalin, histamine, OGFR, T-bet, and GATA3 were suppressed by tranexamic acid treatment. Conversely, the levels of ß-endorphin and µ-opioid receptor increased with tranexamic acid treatment. In addition, the expression of the estrogen receptor-ß on the surface of mast cells was increased by tranexamic acid. These results indicate that photoaging induced by UVA eye irradiation can be ameliorated by tranexamic acid through the regulation of hypothalamo-pituitary hormones. Furthermore, this ameliorative effect on photoaging may be due to an increase in estrogen receptor-ß after tranexamic acid treatment.