CHLOROPLAST UNUSUAL POSITIONING 1 is a plant-specific actin polymerization factor regulating chloroplast movement.

Plants have unique responses to fluctuating light conditions. One such response involves chloroplast photorelocation movement, which optimizes photosynthesis under weak light by the accumulation of chloroplasts along the periclinal side of the cell, which prevents photodamage under strong light by avoiding chloroplast positioning toward the anticlinal side of the cell. This light-responsive chloroplast movement relies on the reorganization of chloroplast actin (cp-actin) filaments. Previous studies have suggested that CHLOROPLAST UNUSUAL POSITIONING 1 (CHUP1) is essential for chloroplast photorelocation movement as a regulator of cp-actin filaments. In this study, we conducted comprehensive analyses to understand CHUP1 function. Functional, fluorescently tagged CHUP1 colocalized with and was coordinately reorganized with cp-actin filaments on the chloroplast outer envelope during chloroplast movement in Arabidopsis thaliana. CHUP1 distribution was reversibly regulated in a blue light- and phototropin-dependent manner. X-ray crystallography revealed that the CHUP1-C-terminal domain shares structural homology with the formin homology 2 (FH2) domain, despite lacking sequence similarity. Furthermore, the CHUP1-C-terminal domain promoted actin polymerization in the presence of profilin in vitro. Taken together, our findings indicate that CHUP1 is a plant-specific actin polymerization factor that has convergently evolved to assemble cp-actin filaments and enables chloroplast photorelocation movement.

Guard-Cell-Specific Expression of Phototropin2 C-Terminal Fragment Enhances Leaf Transpiration.

Phototropins (phot1 and phot2) are plant-specific blue light receptors that mediate chloroplast movement, stomatal opening, and phototropism. Phototropin is composed of the N-terminus LOV1 and LOV2 domains and the C-terminus Ser/Thr kinase domain. In previous studies, 35-P2CG transgenic plants expressing the phot2 C-terminal fragment-GFP fusion protein (P2CG) under the control of 35S promoter showed constitutive phot2 responses, including chloroplast avoidance response, stomatal opening, and reduced hypocotyl phototropism regardless of blue light, and some detrimental growth phenotypes. In this study, to exclude the detrimental growth phenotypes caused by the ectopic expression of P2C and to improve leaf transpiration, we used the PHOT2 promoter for the endogenous expression of GFP-fused P2C (GP2C) (P2-GP2C) and the BLUS1 promoter for the guard-cell-specific expression of GP2C (B1-GP2C), respectively. In P2-GP2C plants, GP2C expression induced constitutive phototropin responses and a relatively dwarf phenotype as in 35-P2CG plants. In contrast, B1-GP2C plants showed the guard-cell-specific P2C expression that induced constitutive stomatal opening with normal phototropism, chloroplast movement, and growth phenotype. Interestingly, leaf transpiration was significantly improved in B1-GP2C plants compared to that in P2-GP2C plants and WT. Taken together, this transgenic approach could be applied to improve leaf transpiration in indoor plants.

The Androgenic Alopecia Protective Effects of Forsythiaside-A and the Molecular Regulation in a Mouse Model.

This study examined the inhibitory effect of forsythiaside-A, a natural substance derived from Forsythia suspensa (F. suspensa), on entry into catagen induced by dihydrotestosterone (DHT) in an androgenic alopecia mouse model. In vitro experiment comparing finasteride with forsythiaside-A showed that forsythiaside-A treatment resulted in a 30% greater inhibition of DHT-induced apoptosis in human hair dermal papilla cell (HHDPCs) and human keratinocytes (HaCaTs). In vivo experiment showed that mouse hair density and thickness were increased by 50% and 30%, respectively, in the forsythiaside-A-treated group when compared to a DHT group. Tissue histological results revealed that the forsythiaside-A-treated group had an increase in size and shape of the hair follicles and a 1.5 times increase in the follicle anagen/telogen ratio when compared to the finasteride group. Western blot examination of TGF-ß2 expression related to apoptosis signaling in mouse skin verified that forsythiaside-A reduced the expression of TGF-ß2 by 75% and suppressed apoptosis by reducing the expression of caspase-9 by 40%, and caspase-3 by 53%, which play an roles up-regulator in the apoptosis signal. The forsythiaside-A group also showed a 60% increase in the Bcl-2/Bax ratio, which is a factor related to mitochondrial apoptosis. Our results indicated that forsythiaside-A prevents apoptosis by similar mechanism with finasteride, but forsythiaside-A is more effective than finasteride. In summary, forsythiaside-A controlled the apoptosis of hair cells and retarded the entry into the catagen phase and therefore represents a natural product with much potential for use as a treatment for androgenic alopecia.

Effects of Galla chinensis extracts on UVB-irradiated MMP-1 production in hairless mice.

Galla chinensis (GAC) is a natural traditional Chinese medicine that has been widely used in folk medicine. Although GAC compounds (mainly gallic acid and methyl gallate) possess strong antiviral, antibacterial, anticancer, and antioxidant activities, there is no report regarding topical or oral administration of GAC compounds on UVB irradiation-induced photoaging in hairless mice (SKH: HR-1). In the present study, we examined cell viability, intracellular reactive oxygen species (ROS), matrix metalloproteinase-1 (MMP-1), and interleukin-6 (IL-6) in skin fibroblasts and keratinocytes induced by UVB in vitro. We also studied skin damage by measuring skin thickness, elasticity, wrinkling and levels of protein MMP-1, elastin, procollagen type I, and transforming growth factor-ß1 (TGF-ß1) in hairless mouse skin chronically irradiated by UVB in vivo. GAC treatment significantly prevented skin photoaging by reducing the levels of ROS, MMP-1, and IL-6 and promoting production of elastin, procollagen type I, and TGF-ß1. According to the results of H&E staining and Masson's trichrome staining, GAC reduced skin thickness and wrinkle formation while it increased skin elasticity. The effects of GAC on UVB-induced skin photoaging may be due to suppressed MMP-1 expression. These findings could be referenced for the development of new agents that target UVB-induced photoaging.

Vigna angularis water extracts protect against ultraviolet b-exposed skin aging in vitro and in vivo.

Exposure to ultraviolet (UV) radiation induces various pathological changes, such as thickened skin and wrinkle formation. In particular, UVB irradiation increases matrix metalloproteinase (MMP)-1 production and collagen degradation, leading to premature aging, termed photoaging. The azuki bean (Vigna angularis; VA) has been widely used as a food product as well as a traditional medicine. However, its activity needs additional study to confirm its functional application in foods and cosmetics for protecting skin. In this study, hot-water extract from VA (VAE) and its active component, rutin, were investigated to determine their antiphotoaging effects. VAE was found to have antioxidant activity. In UVB-exposed normal human dermal fibroblasts cells with VAE and rutin treatments, MMP-1 production was significantly suppressed (90% and 47%, respectively). The effects of both topical and oral administration of VAE were tested in UVB-irradiated hairless mice. VAE suppressed wrinkle formation and skin thickness by promoting elastin, procollagen type I, and TGF-ß1 expression (118%, 156%, and 136%, respectively) and by diminishing MMP-1 production. These results suggest that VAE may be effective for preventing skin photoaging accelerated by UVB radiation.

The inductive effect of ginsenoside F2 on hair growth by altering the WNT signal pathway in telogen mouse skin.

This study was conducted to confirm the possibility of using minor ginseng saponin F2 by oral administration on hair anagen induction effects. The signaling pathway and anagen induction effect of ginsenoside F2 were investigated and compared with finasteride on the effect of hair growth induction. The cell-based MTT assay results indicated that the proliferation rates of HHDPC and HaCaT treated with F2 significantly increased by 30% compared with the finasteride-treated group. A western blot study showed that the expression of ß-catenin Lef-1 and DKK-1 increased by 140, 200% and decreased by 40% in the F2-treated group, respectively compared to that of finasteride-treated group. C57BL/6 mice were subjected to the same treatments. The hair growth promotion rates were compared with groups treated with finasteride, which was 20% higher in the F2-treated group. Tissue histological analysis results showed the number of hair follicles, thickness of the epidermis, and follicles of the anagen phase which increased in the F2-treated group, compared with the finasteride-treated groups. Moreover, the effect of F2 on hair growth was confirmed through the immunofluorescence (IF) methods indicating the expression aspect of Wnt signal pathway-related factors in the tissue of C57BL/6 mouse. Our results considered the expression increase in ß-catenin, Lef-1 which was suggested as a major factor related to the development and growth of hair follicle and the decrease in DKK-1 when entering catagen by F2. As the data showed, F2 might be a potential new therapeutic source for anagen induction and hair growth through the Wnt signal pathway.