αB-crystallin is highly expressed in the heart and slow skeletal muscle; however, the roles of αB-crystallin in the muscle are obscure. Previously, we showed that αB-crystallin localizes at the sarcomere Z-bands, corresponding to the focal adhesions of cultured cells. In myoblast cells, αB-crystallin completely colocalizes with microtubules and maintains cell shape and adhesion. In this study, we show that in beating cardiomyocytes α-tubulin and αB-crystallin colocalize at the I- and Z-bands of the myocardium, where it may function as a molecular chaperone for tubulin/microtubules. Fluorescence recovery after photobleaching (FRAP) analysis revealed that the striated patterns of GFP-αB-crystallin fluorescence recovered quickly at 37°C. FRAP mobility assay also showed αB-crystallin to be associated with nocodazole-treated free tubulin dimers but not with taxol-treated microtubules. The interaction of αB-crystallin and free tubulin was further confirmed by immunoprecipitation and microtubule sedimentation assay in the presence of 1–100 μM calcium, which destabilizes microtubules. Förster resonance energy transfer analysis showed that αB-crystallin and tubulin were at 1–10 nm apart from each other in the presence of colchicine. These results suggested that αB-crystallin may play an essential role in microtubule dynamics by maintaining free tubulin in striated muscles, such as the soleus or cardiac muscles.

No abstract

The skin and lungs are barriers to environmental threats such as toxic chemicals and microbial pathogens. The integrity of the extracellular matrix (ECM) in the dermal papillae in the skin and the interstitium in the lungs is critical for tissue homeostasis. However, it is difficult to improve the ECM integrity in the skin and lung simultaneously. Previously, we reported that eggshell membrane (ESM) provided a young ECM environment to dermal fibroblasts in vitro and in mouse skin and increased the elasticity of human skin. Herein, lung fibroblasts cultured on ESM showed markedly higher type III collagen, decorin, and MMP2 levels. Oral ESM administration in mice markedly increased the type III collagen and decorin levels in lung tissues after 2 weeks, and type III collagen, decorin, and MMP2 levels in the papillary dermis after 4 weeks. Furthermore, in a double-blind study involving 30 adults, the arm skin elasticity significantly increased after 8 weeks of ESM administration. Simultaneously, the Tiffeneau-Pinelli index, which is correlated with lung elasticity, increased also significantly. To further explore the effects of ESM on the lungs, we used a mouse model of bleomycin-induced fibrosis. In these mice, ESM significantly suppressed fibrosis at 2 weeks and increased the type III collagen levels in the bronchioles and decorin levels in the alveoli, which was implicated in the suppression of lung fibrosis. Thus, oral ESM intake may prevent the age-dependent decline of the papillary dermis and pulmonary fibrosis by improving the extracellular environment in skin and lung tissues.

No abstract

Chicken eggshell membrane (ESM) is composed of fibrous proteins cross-linked by collagen (mainly types X and V) lysyl oxidase (LOX) and other molecules, including glycoproteins and lipids [1-3]. Previously, we succeeded in obtaining tritium ( 3 H)labeled ESM using the 6 Li (n, α) 3 H reaction via neutron irradiation and demonstrated that ESM is digested and absorbed into the body [4].