Enhancement of Cell Adhesion by Anaplasma phagocytophilum Nucleolin-Interacting Protein AFAP.

Anaplasma phagocytophilum, the aetiologic agent of human granulocytic anaplasmosis (HGA), is an obligate intracellular Gram-negative bacterium. During infection, A. phagocytophilum enhances the adhesion of neutrophils to the infected endothelial cells. However, the bacterial factors contributing to this phenomenon remain unknown. In this study, we characterized a type IV secretion system substrate of A. phagocytophilum, AFAP (an actin filament-associated Anaplasma phagocytophilum protein) and found that it dynamically changed its pattern and subcellular location in cells and enhanced cell adhesion. Tandem affinity purification combined with mass spectrometry identified host nucleolin as an AFAP-interacting protein. Further study showed the disruption of nucleolin by RNA interference, and the treatment of a nucleolin-binding DNA aptamer AS1411 attenuated AFAP-mediated cell adhesion, indicating that AFAP enhanced cell adhesion in a nucleolin-dependent manner. The characterization of cell adhesion-enhancing AFAP and the identification of host nucleolin as its interaction partner may help understand the mechanism underlying A. phagocytophilum-promoting cell adhesion, facilitating the elucidation of HGA pathogenesis.

Impact of Aging on the Characterization of Brown and White Adipose Tissue-Derived Stem Cells in Mice.

Adipose tissue enriched with adipose tissue-derived stem cells (ASCs) is often used for stem cell-based therapies. However, the characteristics of ASCs from different types of adipose tissue have varying biochemical and functional properties. We aimed to investigate how age affected the biological and functional characteristics of ASCs from brown (BAT) and white adipose tissue (WAT). ASCs were obtained and cultured from mouse BAT and WAT at different ages: young (2 months of age) and older mice (22 months of age). Mesenchymal markers were characterized by flow cytometry, and cell proliferation, apoptosis, differentiation potential, senescence, and metabolism were then determined. The percentage of WAT was higher in elderly mice, and the percentage of BAT was higher in young mice. All ASC sample phenotypes were characterized as CD29+/CD44+/CD105+/CD45-; the proliferation rate was not statistically different among all age groups. However, the number of senescent cells and the percentage of apoptosis in elderly mouse ASCs were significantly increased, and the ability of osteogenic and lipogenic differentiation was decreased in these same animals. In addition, ASCs from young mice were more inclined to undergo osteogenic differentiation, especially BAT-ASCs, whose gene expression of fat-consuming components was also significantly higher than of WAT-ASCs. The results indicated that ASCs derived from both WAT and BAT possessed different characteristics of fat metabolism and cell differentiation relative to the osteo- and adipolineages. In particular, because BAT-ASCs from young mice contributed to fat consumption, if used for cell grafting, they may potentially be attractive vehicles for treating obesity.

Cited2 regulates proliferation and survival in young and old mouse cardiac stem cells.

BACKGROUND: Cardiac stem cells (CSCs) exhibit age-dependent characteristics. Cited2 has been implicated in the regulation of heart development; however, there is little known about how Cited2 affects CSC aging. RESULTS: Cited2 mRNA and protein level was downregulated in aging heart tissue and CSCs. Old (O)-CSCs showed decreased differentiation and proliferation capacities as compared to Young (Y)-CSCs, the decrease in cell proliferation, increase in apoptosis, and cell cycle arrest in G0/G1 phase in CSCs are mediated by knocdown CITED2expression in (Y)-CSCs. CONCLUSIONS: Cited2 plays an important role in cell cycle progression and in maintaining the balance between CSC proliferation and apoptosis in the process of aging without influencing cell fate decisions. These findings have important implications for cell-based therapies for heart repair.

Complete mitochondrial genome of the laced fritillary Argyreus hyperbius (Lepidoptera: Nymphalidae).

We investigated the complete mitochondrial genome (mitogenome) of Argyreus hyperbius. The 15156 bp long genome harbored the gene content (13 protein coding genes, 22 tRNA genes, 2 rRNA genes and an A+T-rich region) and the gene arrangement was identical to all known lepidopteran mitogenomes. Mitogenome sequence nucleotide organization and codon usage analyses showed that the genome had a strong A+T bias, accounting for A+T content of 80.8%, with a small negative AT skew (-0.019). Eleven intergenic spacers totaling 96 bp, and 14 overlapping regions totaling 34 bp were scattered throughout the whole genome. As has been observed in other lepidopteran species, 12 of the 13 protein-coding genes (PCGs) were initiated by ATN codons, while the COI gene was tentatively designated by the CGA codon. A total of 11 PCGs harbored the complete termination codon TAA, while the COI and COII genes ended at a single T residue. All of the 22 tRNA genes showed typical clover structures except that the tRNA(Ser(AGN)) lacks the dihydrouridine (DHU) stem which is replaced by a simple loop. The intergenic spacer sequence between the tRNA(Ser(AGN)) and ND1 also contained the ATACTAA motif, which is conserved in all other lepidopterans as well. Additionally, the 349 bp A+T-rich region was not comprised of large tandem repetitive sequences, but harbored a few structures common to other lepidopteran insects, such as the motif ATAGA followed by a 20 bp poly-T stretch, a microsatellite-like (AT)(9) element preceded by the ATTTA motif, and a 5 bp poly-A site present immediately upstream of tRNA(Met). The mitochondrial genomic sequence features found in this study not only contribute to genetic diversity information of the group, but also are useful in future studies of the endangered nymphalid butterfly in population genetic dynamics, species conservation, phylogeography and evolution.

The complete mitochondrial genome of the yellow coaster, Acraea issoria (Lepidoptera: Nymphalidae: Heliconiinae: Acraeini): sequence, gene organization and a unique tRNA translocation event.

In this paper, the complete mitochondrial genome of Acraea issoria (Lepidoptera: Nymphalidae: Heliconiinae: Acraeini) is reported; a circular molecule of 15,245 bp in size. For A. issoria, genes are arranged in the same order and orientation as the complete sequenced mitochondrial genomes of the other lepidopteran species, except for the presence of an extra copy of tRNA(Ile(AUR)b) in the control region. All protein-coding genes of A. issoria mitogenome start with a typical ATN codon and terminate in the common stop codon TAA, except that COI gene uses TTG as its initial codon and terminates in a single T residue. All tRNA genes possess the typical clover leaf secondary structure except for tRNA(Ser(AGN)), which has a simple loop with the absence of the DHU stem. The sequence, organization and other features including nucleotide composition and codon usage of this mitochondrial genome were also reported and compared with those of other sequenced lepidopterans mitochondrial genomes. There are some short microsatellite-like repeat regions (e.g., (TA)(9), polyA and polyT) scattered in the control region, however, the conspicuous macro-repeats units commonly found in other insect species are absent.