Royal jelly contains numerous components, including proteins. Major royal jelly protein (MRJP) 1 is the most abundant protein among the soluble royal jelly proteins. In its physiological state, MRJP 1 exists as a monomer and/or oligomer. This study focuses the molecular characteristics and functions of MRJP 1 oligomer. MRJP 1 oligomer purified using HPLC techniques was subjected to the following analyses. The molecular weight of MRJP 1 oligomer was found to be 290 kDa using blue native-PAGE. MRJP 1 oligomer was separated into 55 and 5 kDa spots on 2-D blue native/SDS-PAGE. The 55 kDa protein was identified as MRJP 1 monomer by proteome analysis, whereas the 5 kDa protein was identified as Apisimin by N-terminal amino acid sequencing, and this protein may function as a subunit-joining protein within MRJP 1 oligomer. We also found that the oligomeric form included noncovalent bonds and was stable under heat treatment at 56 degrees C. Furthermore, MRJP 1 oligomer dose dependently enhanced and sustained cell proliferation in the human lymphoid cell line Jurkat. In conclusion, MRJP 1 oligomer is a heat-resistant protein comprising MRJP 1 monomer and Apisimin, and has cell proliferation activity. These findings will contribute to further studies analyzing the effects of MRJP 1 in humans.

No abstract

In tooth root development, periodontal ligament (PDL) and cementum are formed by the coordination with the fragmentation of Hertwig's epithelial root sheath (HERS) and the differentiation of dental follicle mesenchymal cells. However, the function of the dental epithelial cells after HERS fragmentation in the PDL is not fully understood. Here, we found that TGF-β regulated HERS fragmentation via epithelial-mesenchymal transition (EMT), and the fragmented epithelial cells differentiated into PDL fibroblastic cells with expressing of PDL extracellular matrix (ECM). In the histochemical analysis, TGF-β was expressed in odontoblast layer adjacent of HERS during root development. Periostin expression was detected around fragmented epithelial cells on the root surface, but not in HERS. In the experiment using an established mouse HERS cell line (HERS01a), TGF-β1 treatment decreased E-cadherin and relatively increased N-cadherin expression. TGF-β1 treatment in HERS01a induced further expression of important ECM proteins for acellular cementum and PDL development such as fibronectin and periostin. Taken together, activation of TGF-β signaling induces HERS fragmentation through EMT and the fragmented HERS cells contribute to formation of PDL and acellular cementum through periostin and fibronectin expression.

TGF-β Regulates TNC During Palatogenesis signal cascade may work in the later stage of palatogenesis when cranial neural crest cells have differentiated into fibroblast-like cells. The spatiotemporal regulation of ECM-related proteins by TGF-β and SHH signaling may contribute not only to tissue construction but also to cell differentiation or determination along the anterior-posterior axis of the palatal shelves.

No abstract