Inhibition of retinoid X receptor improved the morphology, localization of desmosomal proteins and paracellular permeability in three-dimensional cultures of mouse keratinocytes.

Retinoic acid (RA) plays an important role in epithelial homeostasis and influences the morphology, proliferation, differentiation and permeability of epithelial cells. Mouse keratinocytes, K38, reconstituted non-keratinized stratified epithelium in three-dimensional (3D) cultures with serum, which contains retinol (a source of RA), but the morphology was different from in vivo epithelium. The formed epithelium was thick, with loosened cell-cell contacts. Here, we investigated whether the inhibition of RA receptor (RAR)/retinoid X receptor (RXR)-mediated signaling by an RXR antagonist, HX 531, improved K38 3D cultures in terms of morphology and intercellular junctions. The epithelium formed by 0.5 μM HX531 was thin, and the intercellular space was narrowed because of the restoration of the layer-specific distribution of desmoglein (DSG)-1, DSG3 and plakoglobin (PG). Moreover, the levels of desmosomal proteins and tight junction proteins, including DSG1, DSG2, DSG3, PG, claudin (CLDN)-1 and CLDN4 increased, but the adherens junction protein, E-cadherin, did not show any change. Furthermore, CLDN1 was recruited to occludin-positive cell-cell contacts in the superficial cells and transepithelial electrical resistance was increased. Therefore, K38 3D cultures treated with 0.5 μM HX531 provides a useful in vitro model to study intercellular junctions in the non-keratinized epithelium.福岡歯科大学2021年

The reduced susceptibility of mouse keratinocytes to retinoic acid may be involved in the keratinization of oral and esophageal mucosal epithelium.

Keratinocytes take up serum-derived retinol (vitamin A) and metabolize it to all-trans-retinoic acid (atRA), which binds to the nuclear retinoic acid receptor (RAR). We previously reported that serum-affected keratinocyte differentiation and function; namely, it inhibited keratinization, decreased loricrin (LOR) and claudin (CLDN) 1 expression, increased keratin (K) 4 and CLDN4 levels, and reduced paracellular permeability in three-dimensional (3D) cultures of mouse keratinocytes (COCA). Contrarily, RAR inhibition reversed these changes. Here, we aimed to examine whether atRA exerted the same effects as serum, and whether it was involved in the differential oral mucosa keratinization among animal species. Porcine oral mucosal keratinocytes, which form non-keratinized epithelium in vivo, established keratinized epithelium in 3D cultures. Both mouse and porcine sera induced non-keratinized epithelium at 0.1% in COCA 3D cultures. Although atRA caused the same changes as serum, its effective concentration differed. atRA inhibited keratinization at 0.1 nM and 1 nM in porcine or human keratinocytes and COCA, respectively. Furthermore, atRA upregulated CLDN7 in the cytoplasm but not in cell-cell contacts. These atRA-induced changes were reverted by RAR inhibition. The results indicate that serum-induced changes are probably due to the effect of serum-derived atRA, and that mouse keratinocytes require higher atRA concentrations to suppress keratinization than porcine and human keratinocytes. We propose that the lower susceptibility of mouse keratinocytes to atRA, rather than a lower retinol concentration, is a possible reason for the keratinization of mouse oral mucosal epithelium.福岡歯科大学2019年

Incidence of Postoperative Pneumonia and Oral Microbiome for Patients with Cancer Operation

Postoperative pneumonia is a serious problem for patients and medical staff. In Japan, many hospitals introduced perioperative oral care management for the efficient use of medical resources. However, a high percentage of postoperative pneumonia still developed. Therefore, there is a need to identify the specific respiratory pathogens to predict the incidence of pneumonia The purpose of this study was to find out the candidate of bacterial species for the postoperative pneumonia. This study applied case-control study design for the patients who had a cancer operation with or without postoperative pneumonia. A total of 10 patients undergoing a cancer operation under general anesthesia participated in this study. The day before a cancer operation, preoperative oral care management was applied. Using the next generation sequence, oral microbiome of these patients was analyzed at the time of their first visit, the day before and after a cancer operation. Porphyromonas gingivalis and Fusobacterium nucleatum group can be a high risk at first visit. Atopobium parvulum and Enterococcus faecalis before a cancer operation can be a high risk. Poor oral hygiene increased the risk of incidence of postoperative pneumonia. Increased periodontal pathogens can be a high risk of the incidence of postoperative pneumonia. In addition, increased intestinal bacteria after oral care management can also be a high risk for the incidence of postoperative pneumonia

Incidence of Postoperative Pneumonia and Oral Microbiome for Patients with Cancer Operation

Postoperative pneumonia is a serious problem for patients and medical staff. In Japan, many hospitals introduced perioperative oral care management for the efficient use of medical resources. However, a high percentage of postoperative pneumonia still developed. Therefore, there is a need to identify the specific respiratory pathogens to predict the incidence of pneumonia The purpose of this study was to find out the candidate of bacterial species for the postoperative pneumonia. This study applied case-control study design for the patients who had a cancer operation with or without postoperative pneumonia. A total of 10 patients undergoing a cancer operation under general anesthesia participated in this study. The day before a cancer operation, preoperative oral care management was applied. Using the next generation sequence, oral microbiome of these patients was analyzed at the time of their first visit, the day before and after a cancer operation. Porphyromonas gingivalis and Fusobacterium nucleatum group can be a high risk at first visit. Atopobium parvulum and Enterococcus faecalis before a cancer operation can be a high risk. Poor oral hygiene increased the risk of incidence of postoperative pneumonia. Increased periodontal pathogens can be a high risk of the incidence of postoperative pneumonia. In addition, increased intestinal bacteria after oral care management can also be a high risk for the incidence of postoperative pneumonia