Involvement of Heat-Shock Proteins During Periodontal Ligament Remodeling

Mechanical stress induces various molecules such as heat-shock protein (HSP), which causes structural changes in the proteins in periodontal ligament (PDL). We carried out an experiment to induce traumatic occlusion in mouse PDL and analyzed the expression of HSPs. HSPs investigated acts differently depending on the time of expression. HSPs are constitutively expressed in the PDL and defend cells from stress and maintain homeostasis under normal conditions. During bone addition to the PDL on the tension side, HSP27 and HSP47, HSP70 also acts as molecular chaperone, which assists the maturation of bone morphogenetic proteins and aids osteoblast activation. In HSP 70 and HSP 47, mechanical stress is applied to the PDL on the tension side for a short period of time for alveolar bone repairing, and when abnormality occurs in the collagen structure fibroblasts of PDL, it functions at the injured site, whereby extracellular that promotes abnormal collagen secretion and stores the modified protein in the endoplasmic reticulum, there by controlling the decalcification of PDL. In other words, HSP47 and HSP70 are expressed in PDL fibroblasts on the pressure side damaged by application of mechanical stress and contribute to the repair of collagen tissue by activating PDL fibroblasts, supporting recovery from cell damage

Bone Marrow Mesenchymal Cell Contribution in Maintenance of Periodontal Ligament Homeostasis

In general, remodeling phenomenon of the periodontal ligament (PDL) is occurring in all times. Thus, in the chapter, the word “maintenance” was used, and the chapter title is “Maintenance of Periodontal Ligament Homeostasis.” Our experimental data on the remodeling of the PDL with cell acceleration at the furcation area in this experimental model are recovered using the cells in situ and the bone marrow-derived cells (BMCs). BMC migration into the PDL tissues using green fluorescent protein (GFP) bone marrow-transplanted model mouse was examined. BMCs have abilities of cell migration and differentiation into tissues/organs in the body. The immunohistochemistry revealed that GFP-positive cells were detected in the PDL. GFP-positive cells were also positive to CD31, CD68, and Runx2 suggesting that fibroblasts differentiated into osteoclasts and tissue macrophages. In this way, Notch signaling involvement considered in our tentative examinations revealed that the experimentally induced periodontal polyp was examined; the cytological dynamics of the cells in granulation tissue are mainly from migration of undifferentiated mesenchymal cells of the bone marrow and differentiate into the tissue-specified cells. Furthermore, the data suggest that cell differentiation is due to Notch signaling

Chapter 3 : Involvement of heat-shock proteins during periodontal logament remondeling.

Mechanical stress induces various molecules such as heat-shock protein (HSP), which causes structural changes in the proteins in periodontal ligament (PDL). We carried out an experiment to induce traumatic occlusion in mouse PDL and analyzed the expression of HSPs. HSPs investigated acts diff erently depending on the time of expression. HSPs are constitutively expressed in the PDL and defend cells from stress and maintain homeostasis under normal conditions. During bone addition to the PDL on the tension side, HSP27 and HSP47, HSP70 also acts as molecular chaperone, which assists the matu-ration of bone morphogenetic proteins and aids osteoblast activation. In HSP 70 and HSP 47, mechanical stress is applied to the PDL on the tension side for a short period of time for alveolar bone repairing, and when abnormality occurs in the collagen structure fi broblasts of PDL, it functions at the injured site, whereby extracellular that promotes abnormal collagen secretion and stores the modifi ed protein in the endoplasmic reticulum, there by controlling the decalcifi cation of PDL. In other words, HSP47 and HSP70 are expressed in PDL fi broblasts on the pressure side damaged by application of mechanical stress and contribute to the repair of collagen tissue by activating PDL fi broblasts, supporting recovery from cell damage.Edited by Jane Manakil,282p,illus. : London : IntechOpen, 2019

歯科矯正学的メカニカルストレスによるマウス歯周組織改造における細胞動態

The purpose of the study was to determine the cell dynamics in periodontal ligament in response to mechanical stress during orthodontic movement. Following Waldo’s method, a square sheet of rubber dam was inserted in between the first and second maxillary molars in 10 ddY mice leaving the stress load for 3 hours. After 3 days and at 1 week, cell count on pressure and tension sides of the periodontal ligament was determined. Furthermore, the type of cell present after mechanical stress was identified using GFP bone marrow transplantation mouse model. Immunohistochemistry was carried out at 0 min (immediately after mechanical stress), 24 hours, 1 week, 2 weeks and 6 months. Temporal changes in the expression of GFP-positive bone marrow derived cells were examined. Moreover, double immunofluorescent staining was performed to determine the type of cell in the periodontal ligament. Cell count on the tension side tremendously increased 3 days after mechanical stress. At 1 week, spindle and round cell count increased compared to the control group. These changes were observed on both tension and pressure sides. Cell count on pressure side at 3 days (22.11+/-13.98) and at 1 week (33.23+/-11.39) was higher compared to the control group (15.26+/-8.29). On the tension side, there was a significantly increased at 3 days (35.46+/-11.85), but decreased at 1 week (29.23+/-13.89) although it is still higher compared to the control group (AD+/-SD: 10.37+/-8.69). Using GFP bone marrow transplantation mouse model, GFP positive cell count increased gradually over time in 6 months. GFP positive cells were also positive to CD31, CD68 and Runx2 suggesting that fibroblasts differentiated into osteoclasts and tissue macrophages. In conclusion, mechanical stress during orthodontic movement promoted the increase in the number of cells in the periodontal ligament on both tension and pressure sides. The increase in the number of cells in the periodontal ligament is believed to be due to the migration and cell division of undifferentiated mesenchymal cells.2015博士（歯学）松本歯科大

Functional Role of HSP47 in the Periodontal Ligament Subjected to Occlusal Overload in Mice

We carried out an experiment to induce traumatic occlusion in mice periodontal tissue and analyzed the expression of HSP47. Continuous traumatic occlusion resulted to damage and remodeling of periodontal ligament as well as increase in osteoclasts and bone resorption. Four days after traumatic occlusion, osteoclasts did not increase but Howship’s lacunae became enlarged. That is, the persistent occlusal overload can destroy collagen fibers in the periodontal ligament. This was evident by the increased in HSP47 expression with the occlusal overload. HSP47 is maintained in fibroblasts for repair of damaged collagen fibers. On the other hand, osteoclasts continue to increase although the load was released. The osteoclasts that appeared on the alveolar bone surface were likely due to sustained activity. The increase in osteoclasts was estimated to occur after load application at day 4. HSP47 continued to increase until day 6 in experiment 2 but then reduced at day 10. Therefore, HSP47 appears after a period of certain activities to repair damaged collagen fibers, and the activity was returned to a state of equilibrium at day 30 with significantly diminished expression. Thus, the results suggest that HSP47 is actively involved in homeostasis of periodontal tissue subjected to occlusal overload

Role of cyclooxygenase-2-mediated prostaglandin E2-prostaglandin E receptor 4 signaling in cardiac reprogramming

Direct cardiac reprogramming from fibroblasts can be a promising approach for disease modeling, drug screening, and cardiac regeneration in pediatric and adult patients. However, postnatal and adult fibroblasts are less efficient for reprogramming compared with embryonic fibroblasts, and barriers to cardiac reprogramming associated with aging remain undetermined. In this study, we screened 8400 chemical compounds and found that diclofenac sodium (diclofenac), a non-steroidal anti-inflammatory drug, greatly enhanced cardiac reprogramming in combination with Gata4, Mef2c, and Tbx5 (GMT) or GMT plus Hand2. Intriguingly, diclofenac promoted cardiac reprogramming in mouse postnatal and adult tail-tip fibroblasts (TTFs), but not in mouse embryonic fibroblasts (MEFs). Mechanistically, diclofenac enhanced cardiac reprogramming by inhibiting cyclooxygenase-2, prostaglandin E2/prostaglandin E receptor 4, cyclic AMP/protein kinase A, and interleukin 1β signaling and by silencing inflammatory and fibroblast programs, which were activated in postnatal and adult TTFs. Thus, anti-inflammation represents a new target for cardiac reprogramming associated with aging

Chapter 6 : Bone marrow masenchymal cell contribution in maintenance of periodontal ligament homeostasis.

In general, remodeling phenomenon of the periodontal ligament (PDL) is occurring in all times. Thus, in the chapter, the word “maintenance” was used, and the chapter title is “Maintenance of Periodontal Ligament Homeostasis.” Our experimental data on the remodeling of the PDL with cell acceleration at the furcation area in this experimental model are recovered using the cells in situ and the bone marrow-derived cells (BMCs).BMC migration into the PDL tissues using green Ěuorescent protein (GFP)bone　marrow-transplanted model mouse was examined. BMCs have abilities of　cell migration and diěerentiation into　tissues/organs in the body. The immunohistochemistry revealed that GFP-positive cells were detected in the PDL.GFP-positive cells were also positive to CD31, CD68, and Runx2 suggesting that ębroblasts diěerentiated into osteoclasts and tissue macrophages. In this　way, Notch signaling involvement considered in our tentative examinations revealed　that the experimentally induced periodontal polyp was examined; the cytological　dynamics of the cells in granulation tissue are mainly from migration of　undiěerentiated mesenchymal cells of the bone marrow and diěerentiate into the　tissue-specięed cells. Furthermore, the data suggest that cell diěerentiation is due to　Notch signaling.Edited by Thomas Heinbockel and Vonnie D.C. Shields : Published in London : IntechOpen, 2019

A Consideration on the Role of HSP70 Appearing in the Periodontal Tissues due to Experimental Orthodontic Force

実験的歯科矯正力によりマウス歯根膜組織に誘導されるHSP70 とp-HSP70 の初期における発現状況の変化を免疫組織化学的に検討した。その結果、対照群歯根膜線維芽細胞はその歯根膜の全周にわたるHSP70 とp-HSP70 の活性が低い状態で保たれていた。実験群では、HSP70 は時間の経過とともに陽性反応が増強していた。p-HSP70は、HSP70の発現より若干遅れて陽性反応の増強を示していた。これらの実験結果はHSP70がホメオスタシスの維持や傷害を受けた細胞の修復、またそのリン酸化したp-HSP70として、牽引側歯根膜組織における骨芽細胞活性化による同部への骨添加傾向へのシフトが正常に行われるよう分子シャペロンとして働いていることを示唆した。We examined immunohistochemical expressions of HSP70 and p-HSP70 in the orthodontic periodontal tissues. In the control group, the HSP70 and p-HSP70 expression was observed in the periodontal ligament fibroblasts and that was kept in low levels. In the experimental group, the strong expression of HSP70 was detected according to over time. However, p-HSP70 expression was a bit delayed. The data suggests thatHSP70 has been closely involved in the repair of tissue to maintain homeostasis of the periodontal tissues by the activation of periodontal ligament fibroblasts. Farthermore, the data also suggests that HSP70 act as a molecular chaperone of osteogenesis through an activation of osteoblasts

Transplanted Bone Marrow-derived Cell Migration into Periodontal Tissues and Cell Differentiation

マウスを用いて、歯周組織に歯科矯正学的メカニカルストレスを負荷することによって生じる牽引側および圧迫側歯根膜組織の変化について、熱ショックタンパクHSP70およびp-HSP70の発現を免疫組織化学的に検討した。HSP70は時間の経過と共に陽性反応が増強した。p-HSP70は、HSP70の発現より遅れて陽性反応の増強を示した。HSP70がホメオスタシスの維持や傷害を受けた細胞の修復、またそのリン酸化したp-HSP70として、牽引側歯根膜組織における骨芽細胞活性化による同部への骨添加傾向へのシフトが正常に行われるよう分子シャペロンとして働き、タンパク質のフォールディングなどの立体構造形成を助けていることが示唆された。Heat shock proteins (HSPs) are induced by not only the heat shock but also the mechanical stress. Orthodontic tooth movement induced mechanical stress in the related periodontal ligament. It is important to examine the inununohistochemical profile change of the Heat shock proteins (HSPs) in the periodontal ligament cells after receiving the mechanical stress for orthodontic treatment. Therefore, we examined the HSPs in the periodontal ligament cells of ddY mice using the Waldo method. In the control group, periodontal ligament was observed as physiological anangement, and which reacted weakly to HSP27 and HSP70. In the experimental group the extension site of the periodontal ligament cells and the expansion of the blood vessel occuned in the traction side. These tissues were strongly reacted to HSP27 and HSP70. The findings suggeste that the HSPsexpression work as the mechanism of maintenance of homeostasis in the periodontal tissues

SARS-CoV-2 disrupts respiratory vascular barriers by suppressing Claudin-5 expression

臓器チップ技術を用いて新型コロナウイルスが血管へ侵入するメカニズムを解明 --Claudin-5発現抑制による呼吸器の血管内皮バリア破壊--. 京都大学プレスリリース. 2022-09-22.A study using an organ-on-a-chip reveals a mechanism of SARS-CoV-2 invasion into blood vessels --Disruption of vascular endothelial barrier in respiratory organs by decreasing Claudin-5 expression--. 京都大学プレスリリース. 2022-09-27.In the initial process of coronavirus disease 2019 (COVID-19), severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2) infects respiratory epithelial cells and then transfers to other organs the blood vessels. It is believed that SARS-CoV-2 can pass the vascular wall by altering the endothelial barrier using an unknown mechanism. In this study, we investigated the effect of SARS-CoV-2 on the endothelial barrier using an airway-on-a-chip that mimics respiratory organs and found that SARS-CoV-2 produced from infected epithelial cells disrupts the barrier by decreasing Claudin-5 (CLDN5), a tight junction protein, and disrupting vascular endothelial cadherin–mediated adherens junctions. Consistently, the gene and protein expression levels of CLDN5 in the lungs of a patient with COVID-19 were decreased. CLDN5 overexpression or Fluvastatin treatment rescued the SARS-CoV-2–induced respiratory endothelial barrier disruption. We concluded that the down-regulation of CLDN5 expression is a pivotal mechanism for SARS-CoV-2–induced endothelial barrier disruption in respiratory organs and that inducing CLDN5 expression is a therapeutic strategy against COVID-19