Epigenetic mechanisms are behind the regulation of the key genes associated with the osteoblastic differentiation of the mesenchymal stem cells: The role of zoledronic acid on tuning the epigenetic changes

Mesenchymal stem cells (MSCs) are multipotent stem cells and show distinct features such as capability for self-renewal and differentiation into several lineages of cells including osteoblasts, chondrocytes, and adipocytes. In this study, the methylation status of the promoter region of zinc finger and BTB domain containing 16 (ZBTB16), twist-related protein 1(Twist1), de novo DNA methyltransferases 3A (DNMT3A), SRY-box 9 (Sox9), osteocalcin (OCN), and peroxisome proliferator-activated receptor γ2 (PPARγ2) genes and their messenger RNA (mRNA) expression levels were evaluated during the osteoblastic differentiation of MSCs (ODMSCs). We planned two experimental groups including zoledronic acid (ZA)-treated and nontreated cells (negative control) which both were differentiated into the osteoblasts. Methylation level of DNA in the promoter regions was assayed by methylation-specific-quantitative polymerase chain reaction (MS-qPCR), and mRNA levels of the target inhibitory/stimulatory genes during osteoblastic differentiation of MSCs were measured using real-time PCR. During the experimental induction of ODMSCs, the mRNA expression of the OCN gene was upregulated and methylation level of its promoter region was decreased. Moreover, Sox9 and PPARγ2 mRNA levels were attenuated and their promoter regions methylation levels were significantly augmented. However, the mRNA expression of the DNMT3A was not affected during the ODMSCs though its methylation rate was increased. In addition, ZA could enhance the expression of the ZBTB16 and decrease its promoter regions methylation and on the opposite side, it diminished mRNA expression of Sox9, Twist1, and PPARγ2 genes and increased their methylation rates. Intriguingly, ZA did not show a significant impact on gene expression and methylation levels the OCN and DNMT3A. We found that methylation of the promoter regions of Sox9, OCN, and PPARγ2 genes might be one of the main mechanisms adjusting the genes expression during the ODMSCs. Furthermore, we noticed that ZA can accelerate the MSCs differentiation to the osteoblast cells via two regulatory processes; suppression of osteoblastic differentiation inhibitor genes including Sox9, Twist1, and PPARγ2, and through promotion of the ZBTB16 expression.     

Protective effect of selenium on vincristine-induced peripheral neuropathy in PC12 cell line

Cytotechnology - Vincristine-induced peripheral neuropathy (VIPN) is the main side effect and major reason for neuropathic pain in cancer survivors treated with vincristine. Vincristine, a...     

miR-146a and miR-150 promote the differentiation of CD133+ cells into T-lymphoid lineage

MicroRNAs control the genes involved in hematopoietic stem cell (HSCs) survival, proliferation and differentiation. The over-expression of miR-146 and miR-150 has been reported during differentiation of HSCs into T-lymphoid lineage. Therefore, in this study we evaluated the effect of their over-expression on CD133⁺ cells differentiation to T cells. miR-146a and miR-150 were separately and jointly transduced to human cord blood derived CD133⁺ cells (>97 % purity). We used qRT-PCR to assess the expression of CD2, CD3ε, CD4, CD8, CD25, T cell receptor alpha (TCR-α) and Ikaros genes in differentiated cells 4 and 8 days after transduction of the miRNAs. Following the over-expression of miR-146a, significant up-regulation of CD2, CD4, CD25 and Ikaros genes were observed (P < 0.01). On the other hand, over-expression of miR-150 caused an increase in the expression of Ikaros, CD4, CD25 and TCR-α. To evaluate the combinatorial effect of miR-146a and miR-150, transduction of both miRNAs was concurrently performed which led to increase in the expression of Ikaros, CD4 and CD3 genes. In conclusion, it seems that the effect of miR-150 and miR-146a on the promotion of T cell differentiation is time-dependant. Moreover, miRNAs could be used either as substitutes or complements of the conventional differentiation protocols for higher efficiency.     

Synergistic Anti-Cancer Activity of the Combination of 1,25-Dihydroxyvitamin D3 and Retinoic Acid in U937 Cell Line

Background:MicroRNA is a form of non-coding RNAs that able to regulate gene expression. miR-424 is one of the members of the regulatory family, which plays an important role in the proliferation and differentiation of myeloid cells. Epigenetic changes can change the level of miR-424 under environmental factors. Therefore, the level of expression of miR-424 in U937 cells of the myeloid line was evaluated in this research under the influence of vitamin D3 (VitD3) and retinoic acid (RA).Methods:In this study, U937 cells were cultured in the presence of VitD3, and RA to evaluate cell proliferation, viability via the trypan blue exclusion test, and expression level of miR-424 by real-time PCR at specific times.Results:Cell proliferation has shown a significant decrease in the RA group versus other groups during incubation times (P < 0.05). In VitD3 group, there was a significant increase in cell proliferation after 24- and 48-hours incubation periods versus other groups. In the VitD3 and RA groups, the increase of cell proliferation caused the downregulation of miR-424. In addition, the upregulation of VitD3 group and downregulation of the RA group were significant versus the control group (P < 0.05).DiscussionWe concluded that the expression level of miR-424 was critically affected in the dose- and time-dependent of RA and VitD3 treatment in the U937 cell line. Treatment with VitD3 decreased the expression of miR-424 and RA treatment increase miR-424 expression level in physiological doses.Key Words: Cell Proliferation, Differentiation, miR-424, U937 Cells     

Modeling seed germination in Melisa officinalis L. in response to temperature and water potential

Seed germination is greatly influenced by both temperature (T) and water potential (ψ) and these factors largely determine germination rate (GR) in the field. Quantitative information about T and ψ effects on seed germination in lemon balm (Melisa officinalis L.) is scarce. The main objective of this study was to quantify seed germination responses of lemon balm to T and ψ, and to determine cardinal temperatures in a laboratory experiment. A segmented model was used to describe the effects of ψ (i.e., T) on GR and other germination parameters. The segmented model estimates were 7.2 °C for base (T _b), 28.9 °C for optimum (T _o), 40.1 °C for ceiling temperature (T _c) and 1.64 physiological days (f _o) (equivalent to a GR_max of 0.610 d^?1 and a thermal time of 35.6 °C days) to reach 50 % maximum germination in the control (0 MPa) treatment (R ² = 0.99, RMSE = 0.005 day^?1). The inherent maximum rate of germination (days) was calculated by the [GR_max = 1/f _o] model. ψ affected cardinal temperatures. From 0 to ?0.76 MPa, when ψ increased, T _b was a constant 7.2 °C to ?0.38 MPa and increased linearly to 20.1 °C as ψ decreased. T _o and f _o increased linearly from 28.9 to 30 °C, and from 1.64 to 5.4 day^?1, respectively as ψ decreased. However, there was no signification difference in T _o as ψ decreased nor did T _c decrease from 40.1 to 35 °C as ψ decreased. T _b, T _c and GR_max were the sole parameters affected by ψ and could be used to characterize differences between ψ treatments with respect to GR at various Ts. Therefore, the segmented model and its parameters can be used in lemon balm germination simulation models.     

The effect of surface roughness on the stress adaptation of trabecular architecture around a cylindrical implant

The effect of implant-bone bonding and the effect of implant surface roughness on bone remodeling near the bone-implant interface were studied by using a surface remodeling theory and the boundary element method. The study has shown that implant attachment plays an important role in bone remodeling near the implant. It has been observed in animal experiments and in clinical situations that the remodeled trabecular bone architecture around a cylindrical implant could vary, on one hand, from a hub surrounding the implant with a set of external spokes to, on the other hand, a hubless situation in which a set of spokes attach directly to the implant. It is shown here that the difference in these structures may be attributed to differences in implant attachment. The results show that the bone with perfect bonding or roller boundary condition without a gap remodeled to a hubless spoke trabecular bone architecture. On the other hand, the roller boundary condition with a specified gap yielded a spoke trabecular architecture with a hub or ring surrounding the implant. These quantitative results mirror the experimental and clinical observations. It is concluded that the hub is a consequence of the gap and not a consequence of the lack of friction between the implant and the bone.