Gene marking with replication-defective retroviral vectors has been used for more than 20 years to track the in vivo fate of cell clones. We demonstrate that retroviral integrations themselves may trigger nonmalignant clonal expansion in murine long-term hematopoiesis. All 29 insertions recovered from clones dominating in serially transplanted recipients affected loci with an established or potential role in the self-renewal or survival of hematopoietic stem cells. Transcriptional dysregulation occurred in all 12 insertion sites analyzed. These findings have major implications for diagnostic gene marking and the discovery of genes regulating stem cell turnover.

Global germ line loss of fat mass- and obesity-associated (FTO) gene results in both the reduction of fat mass and lean mass in mice. The role of FTO in adipogenesis has been proposed, however, that in myogenesis has not. Skeletal muscle is the main component of body lean mass, so its connection with FTO physiologic significance need to be clarified. Here, we assessed the impact of FTO on murine skeletal muscle differentiation by in vitro and in vivo experiments. We found that FTO expression increased during myoblasts differentiation, while the silence of FTO inhibited the differentiation; in addition, skeletal muscle development was impaired in skeletal muscle FTO-deficient mice. Significantly, FTO-promoted myogenic differentiation was dependent on its m6A demethylase activity. Mechanically, we found that FTO downregulation suppressed mitochondria biogenesis and energy production, showing as the decreased mitochondria mass and mitochondrial DNA (mtDNA) content, the downregulated expression of mtDNA-encoding genes and peroxisome proliferator-activated receptor gamma coactivator 1 alpha (PGC-1α) gene, together with declined ATP level. Moreover, the involvement of mTOR-PGC-1α pathway in the connection between FTO and muscle differentiation is displayed, since the expression of FTO affected the activity of mTOR and rapamycin blocked FTO-induced PGC-1α transcription, along with the parallel alteration pattern of FTO expression and mTOR phosphorylation during myoblasts differentiation. Summarily, our findings provide the first evidence for the contribution of FTO for skeletal muscle differentiation and a new insight to study the physiologic significance of RNA methylation.

Toll-like receptor (TLR) and interferon-␥ (IFN-␥

Casticin, a component from Vitex rotundifolia, widely used as an anti-inflammatory agent in Chinese traditional medicine, was reported to have anti-tumor activities. This study aims to examine the anti-leukemic activity of casticin on leukemia cells and its molecular mechanism. Cell viability was measured by MTT method; apoptosis and cell cycle arrest were determined by flow cytometry, AV-PI assay, and DNA fragmentation assay. Western blot were performed to measure the protein expression level. The cell morphology alteration was detected with immunofluorescent analysis and DAPI nuclear staining. Our results showed that the proliferation of leukemia cells, including K562, Kasumi-1, and HL-60, were inhibited by casticin in a time- and dose-dependent manner. The IC50, determined after 48 h incubation, was 5.95 microM, 4.82 microM, and 15.56 microM for K562, HL-60, and Kasumi-1, respectively. The cell cycle analysis demonstrated casticin treatment resulted in a significant G2/M accumulation, concomitant with upregulation of P21waf1 and P27kip1. The percentage of cells in G2/M increased with time of exposure and reached to its climax (75.3%) at 12 h after casticin treatment, and subsequently declined to 27% at 48 h. We found that casticin treatment induced remarkable apoptosis, evidenced by increased percentage of AV-positive PI-negative cells as well as the cleavage of PARP and caspase 3. In addition, DNA fragmentation assay showed the typical apoptotic DNA ladder in casticin-treated K562 cells. Mitotic catastrophe and decreased polymeric tubulin can also be observed in casticin-treated K562 cells. In addition, we found that PI3K/AKT pathway was activated; Ly294002, a PI3K/AKT specific inhibitor, can enhance the anti-leukemic effect of casticin. Taken together, these results demonstrated that casticin induced leukemic cell death via apoptosis and mitotic catastrophe, and could synergize with PI3K/AKT inhibitor, suggesting that casticin could be a promising therapeutic agent against leukemia.

Results: Chinese people experienced greater odds of comorbidities than whites for a given BMI after standardizing for age and sex: 43% for diabetes, 30% for dyslipidemia, 28% for hypertension, 38% for metabolic syndrome, and 48% for hyperuricemia. Comparisons of BMI-mortality associations found that the U-shaped BMI-mortality curve shifted 1-2 kg m 22 to the left in Chinese compared to whites. Compared to whites at BMIs of 25 and 30 kg m 22 , corresponding cutoffs in Chinese were 22.5 and 25.9 kg m 22 in men, and 22.8 and 26.6 kg m 22 in women after both fat and fat distribution were taken into account. Conclusions: Comorbidity, mortality, and body composition data consistently support the use of lower BMI cutoffs in Chinese than those in whites.

Skin and skin appendages are vulnerable to injury, requiring rapidly reliable regeneration methods. In recent years, 3D bioprinting has shown potential for wound repair and regeneration. 3D bioprinting can be customized for skin shape with cells and other materials distributed precisely, achieving rapid and reliable production of bionic skin substitutes, therefore, meeting clinical and industrial requirements. Additionally, it has excellent performance with high resolution, flexibility, reproducibility, and high throughput, showing great potential for the fabrication of tissue-engineered skin. This review introduces the common techniques of 3D bioprinting and their application in skin tissue engineering, focusing on the latest research progress in skin appendages (hair follicles and sweat glands) and vascularization, and summarizes current challenges and future development of 3D skin printing.

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The transcription factor Evi1 has an outstanding role in the formation and transformation of hematopoietic cells. Its activation by chromosomal rearrangement induces a myelodysplastic syndrome with progression to acute myeloid leukemia of poor prognosis. Similarly, retroviral insertion-mediated upregulation confers a competitive advantage to transplanted hematopoietic cells, triggering clonal dominance or even leukemia. To study the molecular and functional response of primary murine hematopoietic progenitor cells to the activation of Evi1, we established an inducible lentiviral expression system. EVI1 had a biphasic effect with initial growth inhibition and retarded myeloid differentiation linked to enhanced survival of myeloblasts in long-term cultures. Gene expression microarray analysis revealed that within 24 h EVI1 upregulated 'stemness' genes characteristic for long-term hematopoietic stem cells (Aldh1a1, Abca1, Cdkn1b, Cdkn1c, Epcam, among others) but downregulated genes involved in DNA replication (Cyclins and their kinases, among others) and DNA repair (including Brca1, Brca2, Rad51). Cell cycle analysis demonstrated EVI1's anti-proliferative effect to be strictly dose-dependent with accumulation of cells in G0/G1, but preservation of a small fraction of long-term proliferating cells. Although confined to cultured cells, our study contributes to new hypotheses addressing the mechanisms and molecular targets involved in preleukemic clonal dominance or leukemic transformation by Evi1.