The effects of actin cytoskeleton perturbation on keratin intermediate filament formation in mesenchymal stem/stromal cells.

F-actin plays a crucial role in composing the three-dimensional cytoskeleton and F-actin depolymerization alters fate choice of mesenchymal stem/stromal cells (MSCs). Here, we investigated differential gene expression and subsequent physiological changes in response to F-actin perturbation by latrunculin B in MSCs. Nineteen genes were down-regulated and 27 genes were up-regulated in the first 15 min after F-actin depolymerization. Functional enrichment analysis revealed that five genes involved in keratin (KRT) intermediate filaments clustering in the chromosome 17q21.2 region, i.e., KRT14, KRT19, KRT34, KRT-associated protein (KRTAP) 1-5, and KRTAP2-3, were strongly up-regulated. Transcription factor prediction identified NKX2.5 as the potential transcription factor to control KRT19, KRT34, KRTAP1-5, and KRTAP2-3; and indeed, the protein level of NKX2.5 was markedly increased in the nuclear fraction within 15 min of F-actin depolymerization. The peak of keratin intermediate filament formation was 1 h after actin perturbation, and the morphological changes showed by decrease in the ratio of long-axis to short-axis diameter in MSCs was observed after 4 h. Together, F-actin depolymerization rapidly triggers keratin intermediate filament formation by turning on keratin-related genes on chromosome 17q21.2. Such findings offer new insight in lineage commitment of MSCs and further scaffold design in MSC-based tissue engineering.

The activation of directional stem cell motility by green light-emitting diode irradiation.

Light-emitting diode (LED) irradiation is potentially a photostimulator to manipulate cell behavior by opsin-triggered phototransduction and thermal energy supply in living cells. Directional stem cell motility is critical for the efficiency and specificity of stem cells in tissue repair. We explored that green LED (530 nm) irradiation directed the human orbital fat stem cells (OFSCs) to migrate away from the LED light source through activation of extracellular signal-regulated kinases (ERK)/MAP kinase/p38 signaling pathway. ERK inhibitor selectively abrogated light-driven OFSC migration. Phosphorylation of these kinases as well as green LED irradiation-induced cell migration was facilitated by increasing adenosine triphosphate (ATP) production in OFSCs after green LED exposure, and which was thermal stress-independent mechanism. OFSCs, which are multi-potent mesenchymal stem cells isolated from human orbital fat tissue, constitutionally express three opsins, i.e. retinal pigment epithelium-derived rhodopsin homolog (RRH), encephalopsin (OPN3) and short-wave-sensitive opsin 1 (OPN1SW). However, only two non-visual opsins, i.e. RRH and OPN3, served as photoreceptors response to green LED irradiation-induced OFSC migration. In conclusion, stem cells are sensitive to green LED irradiation-induced directional cell migration through activation of ERK signaling pathway via a wavelength-dependent phototransduction.

Multiple intravenous transplantations of mesenchymal stem cells effectively restore long-term blood glucose homeostasis by hepatic engraftment and ß-cell differentiation in streptozocin-induced diabetic mice.

Depletion of pancreatic ß-cells results in insulin insufficiency and diabetes mellitus (DM). Single transplantation of mesenchymal stem cells exhibits short-term effects in some preclinical studies. Here, we further investigated the long-term therapeutic effects of multiple intravenous MSC transplantations. In this study, multiple human MSC transplantations (4.2 × 10(7) cells/kg each time) were performed intravenously at 2-week intervals into streptozocin (STZ)-induced diabetic mice for 6 months. Blood sugar, insulin, renal function, cholesterol, and triglyceride levels were monitored. We demonstrated that compared to single intravenous transplantation, which only transiently decreased hyperglycemia, multiple MSC transplantations effectively restored blood glucose homeostasis. Systemic oxidative stress levels were reduced from the seventh week of treatment. From the 11th week, production of human insulin was markedly increased. When MSC transplantation was skipped after blood sugar level returned to normal at the end of 15th week, a sharp rebound of blood sugar occurred, and was then controlled by subsequent transplantations. At the end of 6 months, histopathology examination revealed MSCs specifically engrafted into liver tissues of the recipients. Fifty-one percent of human cells in the recipient liver coexpressed human insulin, especially those surrounding the central veins. Taken together, intravenous MSC delivery was safe and effective for blood glucose stabilization in this preclinical DM model. Multiple transplantations were essential to restore and maintain glucose homeostasis through decreasing systemic oxidative stress in the early stage and insulin production in the late stage. Liver engraftment and differentiation into insulin-producing cells account for the long-term therapeutic effects of MSCs.

Oral administration of Lactobacillus plantarum K68 ameliorates DSS-induced ulcerative colitis in BALB/c mice via the anti-inflammatory and immunomodulatory activities.

Many different kinds of fermented food are consumed daily in Taiwan, such as stinky tofu, suan-tsai, and fu-tsai. We have previously reported the diversity of lactic acid bacteria (LAB) at different stages of fermentation in the production of suan-tsai and fu-tsai. In this study, the anti-inflammatory and immunomodulatory activities of Lactobacillus plantarum K68 (K68) isolated from fu-tsai were evaluated. K68 significantly inhibited the production of tumor necrosis factor-α (TNF-α) and prostaglandin E(2) (PGE(2)) in lipopolysaccharide (LPS)-induced murine macrophage RAW 264.7 cells and stimulated interferon-γ (IFN-γ) production in human peripheral blood mononuclear cells (hPBMCs). Additionally, orally administered K68 ameliorated dextran sulfate sodium (DSS)-induced ulcerative colitis (UC) in BALB/c mice. Both the disease activity index (DAI) and histological scores (HIS) showed that the severity of UC was significantly reduced by oral administration of K68. Furthermore, the production of pro inflammatory cytokines TNF-α, interleukin-1ß (IL-1ß), and interleukin-6 (IL-6) was significantly reduced in K68-administered group. Colonic mRNA expression levels of TNF-α, cyclooxygenase-2 (COX-2), forkhead box P3 (Foxp3), suppressors of cytokine signaling 3 (SOCS3), and toll like receptor 4 (TLR4), were also reduced in the K68-administered group. These results suggest that K68 exhibits anti-inflammatory and immunomodulatory activities that ameliorate DSS-induced experimental colitis.