Core-shell nanoparticle controlled hATSCs neurogenesis for neuropathic pain therapy.

A stem cell-based strategy for tissue engineering in regenerative medicine is crucial to produce and effective therapeutic replacement of injured or damaged tissues. This type of therapeutic replacement requires interaction with the cells and tissues via the incorporation of a beneficial physical microenvironment and cellular biochemical signals. Recently, we studied a cell-function modifying factor, core-shell nanoparticles consisting of an SPIO (superparamagnetic iron oxide) core covered with a photonic ZnO shell for human adipose tissue-derived stem cells (hATSCs) that regulate various cellular functions: self-renewal, neurogenesis, and dedifferentiation. We proposed an alternative method of stem cell culture that focuses on the use of Zn++ Finger nanoparticles for stem cell expansion and transdifferentiation modulation in vitro and in in vivo spinal cord injury models. Our study showed that treating hATSC cultures with nanoscale particles could lead to active cell proliferation and self-renewal and could promote nuclear Dicer-regulation of several functional molecules, Oct4 and Glutathione peroxidase 3 (GPx3), and the abundance of specific functional proteins that have been observed using biochemical analysis. These biochemical changes in hATSCs induced the functional development of multiple differentiation potencies such as ß-cells and neural cells; specifically, the ability to differentiation into GABA-secreting cells was significantly improved in in vitro- and in vivo-induced animal lesions with significantly improved therapeutic modality.

MBD6 is a direct target of Oct4 and controls the stemness and differentiation of adipose tissue-derived stem cells.

Argonaute 2 (Ago2) is a pivotal regulator of cell fate in adult stem cells. Its expression is significantly downregulated in late passages of cells, concomitant with a prominent increase in Ago2 cytosolic localization in single cells. Nuclear localization of Ago2 is crucial for the survival, proliferation, and differentiation of hATSCs (human adipose tissue-derived stem cells), mediated by the specific binding of the regulatory regions of functional genes, which positively or negatively altered gene expression. Ago2 targets genes that control stemness, reactive oxygen species scavenging, and microRNA expression, all of which are crucial for hATSC survival and self-renewal. Ago2 promotes cell proliferation and self-renewal by activating the expression of octamer-binding transcription factor 4 (Oct4). We confirmed the direct regulation of Oct4 activity by Ago2, as indicated by the results of the ChIP analysis. Methyl-CpG-binding protein 6 (MBD6) was detected as an Oct4 regulatory gene. As predicted, knockdown of MBD6 expression attenuated cell proliferation and eventually induced cell death. We hypothesized that MBD6 functions downstream of Oct4 in the regulation of stemness-related genes, cell proliferation, self-renewal activity, and survival. MBD6 also promoted cell transdifferentiation into neural and endodermal ß-cells while significantly attenuating differentiation into the mesodermal lineage. We demonstrate that MBD6 is regulated by Ago2 via an interaction with Oct4, which alters self-renewal and gene expression in hATSCs. MBD6 was promoted cell proliferation through a novel set of signal mediators that may influence differentiation by repressing MBD2 and MBD3, which are possibly recruited by germ cell nuclear factor (GCNF).

The p38 MAPK pathway is critical for 5,5'-dibromodiindolylmethane-induced apoptosis to prevent oral squamous carcinoma cells.

Cruciferous vegetables contain isothiocyanates including diindolylmethane (DIM) that exhibit cancer chemopreventive effects. We developed a series of synthetic ring-substituted DIM analogs including 5,5'-dibromoDIM that exhibited better inhibitory activity in breast and colon cancer cells than DIM. In this study, we investigated whether 5,5'-dibromoDIM inhibits the proliferation of KB and YD-10B oral squamous carcinoma cell lines. 5,5'-dibromoDIM decreased the cell survival and inhibited the growth of oral cancer cells. Exposure of KB and YD-10B cells to 5,5'-dibromoDIM induced caspase-dependent apoptosis evidenced by poly-ADP ribose polymerase cleavage, accumulation of sub-G1 population, and nuclear condensation and fragmentation. In addition, apoptotic cell death was correlated with damage to the mitochondrial membrane potential through a decrease in the level of Bcl-2 protein expression. Mechanistic studies showed that mitochondria-dependent apoptosis induced by 5,5'-dibromoDIM was mediated by the p38 mitogen-activated protein kinase pathway but not the ERK1/2 and JNK pathway. These results highlight 5,5'-dibromoDIM as an important chemopreventive agent for the clinical treatment of oral cancer through the p38 mitogen-activated protein kinase pathway.