Diversity of the MHC class II DRB gene in the wolverine (Carnivora: Mustelidae: Gulo gulo) in Finland.

The wolverine (Gulo gulo) in Finland has undergone significant population declines in the past. Since major histocompatibility complex (MHC) genes encode proteins involved in pathogen recognition, the diversity of these genes provides insights into the immunological fitness of regional populations. We sequenced 862 amplicons (242 bp) of MHC class II DRB exon 2 from 32 Finnish wolverines and identified 11 functional alleles and three pseudogenes. A molecular phylogenetic analysis indicated trans-species polymorphism, and PAML and MEME analyses indicated positive selection, suggesting that the Finnish wolverine DRB genes have evolved under balancing and positive selection. In contrast to DRB gene analyses in other species, allele frequencies in the Finnish wolverines clearly indicated the existence of two regional subpopulations, congruent with previous studies based on neutral genetic markers. In the Finnish wolverine, rapid population declines in the past have promoted genetic drift, resulting in a lower genetic diversity of DRB loci, including fewer alleles and positively selected sites, than other mustelid species analyzed previously. Our data suggest that the MHC region in the Finnish wolverine population was likely affected by a recent bottleneck.

Effect of Astaxanthin on the Expression and Activity of Aquaporin-3 in Skin in an In-Vitro Study.

Astaxanthin (3,3'-dihydroxy-ß,ß-carotene-4,4'-dione) is a red lipophilic pigment with strong antioxidant action. Oral or topical administration of astaxanthin has been reported to improve skin function, including increasing skin moisture. In this study, we examined the mechanism by which astaxanthin improves skin function by focusing on the water channel aquaporin-3 (AQP3), which plays important roles in maintaining skin moisture and function. When astaxanthin was added to PHK16-0b or HaCaT cells, the mRNA expression level of AQP3 increased significantly in a concentration-dependent manner in both cell lines. The AQP3 protein expression level was also confirmed to increase when astaxanthin was added to HaCaT cells. Similarly, when astaxanthin was added to 3D human epidermis model EpiSkin, AQP3 expression increased. Furthermore, when glycerol and astaxanthin were simultaneously added to EpiSkin, glycerol permeability increased significantly compared with that observed for the addition of glycerol alone. We demonstrated that astaxanthin increases AQP3 expression in the skin and enhances AQP3 activity. This result suggests that the increased AQP3 expression in the skin is associated with the increase in skin moisture by astaxanthin. Thus, we consider astaxanthin useful for treating dry skin caused by decreased AQP3 due to factors such as diabetes mellitus and aging.

Canonical Wnt signaling activates miR-34 expression during osteoblastic differentiation.

The canonical Wnt signaling pathway is crucial for the regulation of bone mass in humans and for the development of osteoblasts. MicroRNAs (miRs) represent a class of non­coding RNAs, ~22 nucleotides in length, that regulate gene expression by targeting mRNAs for cleavage or translational repression. Several previous studies have demonstrated the involvement of miRNAs in modulating gene expression in osteoblasts and regulating osteoblast differentiation. In the present study, microRNA profiling was conducted using Wnt3a­C2C12 cells; C2C12 cells were transfected with a Wnt3a expression plasmid to activate canonical Wnt signaling. miR­34b­5p and miR­34c were identified to be upregulated by the activation of canonical Wnt signaling in C2C12 cells. Expression of mature miR­34b/c increased from low levels at day 0 to maximum levels at day 28 of MC3T3­E1 cell differentiation. To analyze the effects of these miRNAs on osteoblast differentiation, an antisense inhibitor was transfected into MC3T3­E1 cells and osteoblast­related gene expression was investigated. Knockdown of miR34b/c enhanced osteocalcin mRNA expression; however, alkaline phosphatase mRNA expression and activity were decreased by miR34b/c inhibition. These results indicated that miR­34b/c regulates gene expression by targeting regulators of the osteogenic pathways and thereby contributes to osteoblast differentiation.