Kyushu University Academic Staff Educational and Research Activities Database
List of Reports
Eijiro Jimi Last modified date:2022.06.24

Professor / Department of Dental Science / Faculty of Dental Science

1. Jimi E, Honda H, Nakamura I., The unique function of p130Cas in regulating the bone metabolism., Pharmacol Ther., 10.1016/j.pharmthera.2021.1, 2021.10.
2. Jimi E, Huang F, Nakatomi C., NF-κB signaling regulates physiological and pathological chondrogenesis., Int J Mol Sci. pii: E6275., doi: 10.3390/ijms20246275., 2019.12, The nuclear factor-κB (NF-κB) is a transcription factor that regulates the expression of genes that control cell proliferation and apoptosis, as well as genes that respond to inflammation and immune responses. There are two means of NF-κB activation: the classical pathway, which involves the degradation of the inhibitor of κBα (IκBα), and the alternative pathway, which involves the NF-κB-inducing kinase (NIK, also known as MAP3K14). The mouse growth plate consists of the resting zone, proliferative zone, prehypertrophic zone, and hypertrophic zone. The p65 (RelA), which plays a central role in the classical pathway, is expressed throughout the cartilage layer, from the resting zone to the hypertrophic zone. Inhibiting the classical NF-κB signaling pathway blocks growth hormone (GH) or insulin-like growth factor (IGF-1) signaling, suppresses cell proliferation, and suppresses bone morphogenetic protein 2 (BMP2) expression, thereby promoting apoptosis. Since the production of autoantibodies and inflammatory cytokines, such as tumor necrosis factor-α (TNFα), interleukin (IL)-1β, IL-6, and IL-17, are regulated by the classical pathways and are increased in rheumatoid arthritis (RA), NF-κB inhibitors are used to suppress inflammation and joint destruction in RA models. In osteoarthritis (OA) models, the strength of NF-κB-activation is found to regulate the facilitation or suppression of OA. On the other hand, RelB is involved in the alternative pathway, and is expressed in the periarticular zone during the embryonic period of development. The alternative pathway is involved in the generation of chondrocytes in the proliferative zone during physiological conditions, and in the development of RA and OA during pathological conditions. Thus, NF-κB is an important molecule that controls normal development and the pathological destruction of cartilage..
3. Jimi E, Takakura N, Hiura F, Nakamura I, Hirata-Tsuchiya S., The Role of NF-κB in physiological bone development and Inflammatory bone diseases: Is NF-κB Inhibition "Killing two birds with one stone"?, Cells. 2019 Dec 14;8(12). pii: E1636., doi: 10.3390/cells8121636., 2019.12, Nuclear factor-κB (NF-κB) is a transcription factor that regulates the expression of various genes involved in inflammation and the immune response. The activation of NF-κB occurs via two pathways: inflammatory cytokines, such as TNF-α and IL-1β, activate the "classical pathway", and cytokines involved in lymph node formation, such as CD40L, activate the "alternative pathway". NF-κB1 (p50) and NF-κB2 (p52) double-knockout mice exhibited severe osteopetrosis due to the total lack of osteoclasts, suggesting that NF-κB activation is required for osteoclast differentiation. These results indicate that NF-κB may be a therapeutic target for inflammatory bone diseases, such as rheumatoid arthritis and periodontal disease. On the other hand, mice that express the dominant negative form of IκB kinase (IKK)-β specifically in osteoblasts exhibited increased bone mass, but there was no change in osteoclast numbers. Therefore, inhibition of NF-κB is thought to promote bone formation. Taken together, the inhibition of NF-κB leads to "killing two birds with one stone": it suppresses bone resorption and promotes bone formation. This review describes the role of NF-κB in physiological bone metabolism, pathologic bone destruction, and bone regeneration..
4. Eijiro Jimi, Vitamin status and mineralized tissue formation, Current Oral Health Reports, 2019.02, Purpose of the Review
Vitamins play important roles in bone health, and vitamin supplementation has been recommended to prevent osteoporosis and to reduce fracture risk in the elderly. However, the benefits of vitamin intake for bone health are still controversial. The aim of the review is to examine the relationship between vitamins and bone health and how vitamins function in osteoblasts and osteoclasts.
Recent Findings
A broad literature search with the PubMed database was performed. The results of human clinical studies are inconsistent due to differences in the study design, race, genetic factors, and the population. Vitamin K, E, or C intake seems to benefit for bone health as well as vitamin D. Recent findings did not support the benefit of the vitamin B complex for bone health. Furthermore, both the excess and deficiency of vitamin A might be involved in compromised bone health.
The well-balanced and adequate amounts of vitamins should be ensured to prevent adverse effects on bone health..
5. Bone remodeling consists of bone resorbing cycle and bone forming cycle to maintain bone volume and calcium homeostasis thought life. The main cells involves in bone remodeling are osteoclasts and osteoblasts. Bone resorption and bone formation are tightly coupled during bone remodeling, an imbalance of these two processes leads to either increased or decreased bone mass. Osteoclasts are multinucleated cells responsible for physiological and pathological bone resorption and thereby play an essential role in maintaining bone volume and homeostasis. Osteoclastic bone resorption is regulated by several cytokines, calcium signal, and transcription factors etc. Recent molecular dissection of genetic disorders of high increased or decreased bone mass has proven many of the crucial molecules controlling the osteoclastic bone resorption. This article reviews recent findings of molecular mechanism regarding to osteoclastic bone resorption to regulate bone remodeling..