Coculturing scaffolds with seeded cells in vitro is an indispensable process for construction of engineered tissues. It is essential to understand effects of the constituent particles of scaffold on seeded cells. In this study, we investigated the influence of nano-sized hydroxyapatite (nHAP) particles on the proliferation and osteogenic differentiation of bone marrow-derived mesenchymal stem cells (MSCs). nHAP particles were cocultured with MSCs separated from rabbit. Cellular effects of particles were determined by cell counts, Vonkossa stains, and reverse transcription-polymerase chain reaction (RT-PCR) examinations. Results showed that nHAP particles could promote the MSCs growth when particle concentrations were lower than 20 microg/10(4) cells. This effect disappeared when the particles and the cells were cocultured in serum-free media. Higher particle concentrations could significantly inhibit the cell growth. Under the standard culture condition, the only effect of nHAP particles on osteogenic differentiation of MSCs was to enhance the expression of collagen I. Under the osteogenic-inductive culture condition, nHAP particles could inhibit mineralization of cells but promote their osteogenic differentiation. These cellular effects of particles still existed when the particles and the cells were cultured in indirect coculture system. nHAP particles could decrease calcium and phosphate concentrations of culture media, which possibly contributed to the cellular effects of nHAP particles.

Rationale: Methylation at the N6 position of adenosine (m 6 A) is the most prevalent RNA modification within protein-coding mRNAs in mammals, and it is a reversible modification with various important biological functions. The formation and function of m 6 A are regulated by methyltransferases (writers), demethylases (erasers), and special binding proteins (readers) as key factors. However, the underlying modification mechanisms of m 6 A in gastrointestinal (GI) cancer remain unclear. Here, we performed comprehensive molecular profiling of the nine known m 6 A writer, eraser, and reader proteins in GI cancer. Methods: Data from The Cancer Genome Atlas (TCGA) and Gene Expression Omnibus (GEO) were used. Gene alteration and pathway analysis were done in cBioportal. The protein network of m 6 A regulators and its related pathway members was analyzed in STRING online platform. Phylogenetic tree was constructed in MEGA7. m 6 A modification sites were predicted by SRAMP. m 6 A related SNPs were analyzed by m 6 ASNP. The modulation of m 6 A on its related pathway members was validated by m 6 A-seq, real-time PCR and phosphor-MAPK array. Results: We found that m 6 A regulators were mostly upregulated in GI cancer and their differential expression significantly influenced the overall survival of patients with GI cancer. The phosphatidylinositol-3-kinase (PI3K)/Akt and mammalian target of rapamycin (mTOR) signaling pathways were found to be potentially affected by m 6 A modification in most human cancers, including GI cancer, which was further verified by m 6 A-Seq and phospho-MAPK array. Conclusions: Our findings suggest that m 6 A RNA modification has a fundamental role in the regulation of PI3K/Akt and mTOR signaling pathway function in cancer.

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Rhodiola species are edible medicinal plants, which have been traditionally used in both Asia and Europe as an adaptogen, tonic, anti-depressant and anti-inflammatory supplement. However, whether it presents therapeutic effect...

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