Honeybees produce royal jelly (RJ) from their cephalic glands. Royal jelly is a source of nutrition for the queen honey bee throughout its lifespan and is also involved in fertility and longevity. Royal jelly has long been considered beneficial to human health. We recently observed that RJ delayed impairment of motor function during aging, affecting muscle fiber size. However, how RJ affects skeletal muscle metabolism and the functional component of RJ is as of yet unidentified. We demonstrate that feeding mice with RJ daily prevents a decrease in myofiber size following denervation without affecting total muscle weight. RJ did not affect atrophy-related genes but stimulated the expression of myogenesis-related genes, including IGF-1 and IGF receptor. Trans-10-hydroxy-2-decenoic acid (10H2DA) and 10-hydroxydecanoic acid (10HDAA), two major fatty acids contained in RJ. After ingestion, 10H2DA and 10HDAA are metabolized into 2-decenedioic acid (2DA) and sebacic acid (SA) respectively. We found that 10H2DA, 10HDAA, 2DA, and SA all regulated myogenesis of C2C12 cells, murine myoblast cells. These novel findings may be useful for potential preventative and therapeutic applications for muscle atrophy disease included in Sarcopenia, an age-related decline in skeletal muscle mass and strength.

Tongue muscle damage impairs speaking and eating, thereby degrading overall health and quality of life. Skeletal muscles of the body are diverse in embryonic origin, anatomic location, and gene expression profiles. Responses to disease, atrophy, aging, or drugs vary among different muscles. Currently, most muscle studies are focused on limb muscles and the tongue is neglected. The regenerative ability of tongue muscle remains unknown, and thus there is need for tongue muscle research models. Here, we present a comprehensive characterization of the spatiotemporal dynamics in a mouse model of tongue muscle regeneration and establish a method for the isolation of primary tongue-derived satellite cells. We compare and contrast our observations with the tibialis anterior (TA) limb muscle. Acute injury was induced by intramuscular injection of cardiotoxin, a cytolytic agent, and examined at multiple timepoints. Initially, necrotic myofibers with fragmented sarcoplasm became infiltrated with inflammatory cells. Concomitantly, satellite cells expanded rapidly. Seven days postinjury, regenerated myofibers with centralized nuclei appeared. Full regeneration, as well as an absence of fibrosis, was evident 21 d postinjury. Primary tongue-derived satellite cells were isolated by enzymatic separation of tongue epithelium from mesenchyme followed by magnetic-activated cell sorting. We observed that tongue displays an efficient regenerative response similar to TA but with slightly faster kinetics. In vitro, tongue-derived satellite cells differentiated robustly into mature myotubes with spontaneous contractile behavior and myogenic marker expression. Comparison of gene expression signatures between tongue and TA-derived satellite cells revealed differences in the expression of positional-identity genes, including the HOX family. In conclusion, we have established a model for tongue regeneration useful for investigations of orofacial muscle biology. Furthermore, we showed that tongue is a viable source of satellite cells with unique properties and inherited positional memory.

Background Melanoma is a malignant tumor characterized by high proliferation and aggressive metastasis. To address the molecular mechanisms of the proto-oncogene, Rous sarcoma oncogene (Src), which is highly activated and promotes cell proliferation, migration, adhesion, and metastasis in melanoma. Plectin, a cytoskeletal protein, has recently been identified as a Src-binding protein that regulates Src activity in osteoclasts. Plectin is a candidate biomarker of certain tumors because of its high expression and the target of anti-tumor reagents such as ruthenium pyridinecarbothioamide. The molecular mechanisms by which plectin affects melanoma is still unclear. In this study, we examined the role of plectin in melanoma tumor formation. Methods We used CRISPR/Cas9 gene editing to knock-out plectin in B16 mouse melanoma cells. Protein levels of plectin and Src activity were examined by western blotting analysis. In vivo tumor formation was assessed by subcutaneous injection of B16 cells into nude mice and histological analysis performed after 2 weeks by Hematoxylin-Eosin (H&E) staining. Cell proliferation was evaluated by direct cell count, cell counting kit-8 assays, cyclin D1 mRNA expression and Ki-67 immunostaining. Cell aggregation and adhesion were examined by spheroid formation, dispase-based dissociation assay and cell adhesion assays. Results In in vivo tumor formation assays, depletion of plectin resulted in low-density tumors with large intercellular spaces. In vitro experiments revealed that plectin-deficient B16 cells exhibit reduced cell proliferation and reduced cell-to-cell adhesion. Since Src activity is reduced in plectin-deficient melanomas, we examined the relationship between plectin and Src signaling. Src overexpression in plectin knockout B16 cells rescued cell proliferation and improved cell-to-cell adhesion and cell to extracellular matrix adhesion. Conclusion These results suggest that plectin plays critical roles in tumor formation by promoting cell proliferation and cell-to-cell adhesion through Src signaling activity in melanoma cells.

Melanoma is malignant cancer characterized by high proliferation and aggressive metastasis. To address efficient treatment for melanoma, we should understand the molecular mechanisms for a proto-oncogene Src, which is highly activated and promotes cell proliferation, migration, adhesion, and metastasis in melanoma. We recently identified plectin as the Src binding protein and regulates Src activity in osteoclasts. Plectin, a cytoskeleton regulatory protein, is focused as the candidates of biomarker of certain tumors because of higher expression and the candidate of anti-tumor reagents such as ruthenium pyridinecarbothioamide although the molecular mechanisms how plectin works in melanoma is unclear. In this study, we examined the pathological role in melanoma tumor formation. Depletion of plectin induced low density and sparce tumor formation by melanoma cells in vivo. In vitro experiment revealed that plectin deficient melanomas reduced cell proliferation and suppressed cell-to-cell adhesion. Because Src activity was reduced in plectin deficient melanomas, we examined the relationship between plectin and Src signaling. Src overexpression that restored Src activity rescued cell proliferation and cell-to-cell adhesion of plectin deficient melanomas. These results suggest that plectin is required for tumor formation by promoting cell proliferation and cell-to-cell adhesion via Src signaling activity in melanoma.

Background Melanoma is a malignant tumor that is characterized by high proliferation and aggressive metastasis. To address the efficient treatment of melanoma, the molecular mechanisms of the proto-oncogene, Rous sarcoma oncogene (Src), which is highly activated and promotes cell proliferation, migration, adhesion, and metastasis in melanoma, should be understood. Plectin has recently been identified as an Src-binding protein that regulates Src activity in osteoclasts. Plectin, a cytoskeleton-regulatory protein, is a candidate biomarker of certain tumors because of its high expression and the target of anti-tumor reagents such as ruthenium pyridinecarbothioamide, although the molecular mechanisms by which plectin works in melanoma are still unclear. In this study, we examined its pathological role in melanoma tumor formation. Methods We established plectin knock-out B16 cells, the mouse melanoma cell line, with CRISPR/Cas9 system. The expression of plectin and activity of Src were examined by western blotting analysis. The tumors were formed at 2 weeks after subcutaneous injection of B16 cells in nude mice and analyzed by Hematoxylin-Eosin (H-E) staining. Cell proliferation was evaluated by cell counting kit-8, expression of cyclin D1 and Ki-67. Cell aggregation and adhesion were assessed by spheroid formation and cell adhesion assay.Results Depletion of plectin induced low-density and sparce tumor formation by melanoma cells in vivo. In vitro experiments revealed that plectin-deficient melanomas exhibit reduced cell proliferation and suppressed cell-to-cell adhesion. Because Src activity is reduced in plectin-deficient melanomas, we examined the relationship between plectin and Src signaling. Src overexpression restored Src activity and rescued cell proliferation and cell-to-cell adhesion in plectin-deficient melanomas. Conclusion: These results suggest that plectin is required for tumor formation by promoting cell proliferation and cell-to-cell adhesion through Src signaling activity in melanoma cells.