Oral intake of Lactobacillus plantarum L-14 extract alleviates TLR2- and AMPK-mediated obesity-associated disorders in high-fat-diet-induced obese C57BL/6J mice.

OBJECTIVES: Whether periodic oral intake of postbiotics positively affects weight regulation and prevents obesity-associated diseases in vivo is unclear. This study evaluated the action mechanism of Lactobacillus plantarum L-14 (KTCT13497BP) extract and the effects of its periodic oral intake in a high-fat-diet (HFD) mouse model. MATERIALS AND METHODS: Mouse pre-adipocyte 3T3-L1 cells and human bone marrow mesenchymal stem cells (hBM-MSC) were treated with L-14 extract every 2 days during adipogenic differentiation, and the mechanism underlying anti-adipogenic effects was analysed at cellular and molecular levels. L-14 extract was orally administrated to HFD-feeding C57BL/6J mice every 2 days for 7 weeks. White adipose tissue was collected and weighed, and liver and blood serum were analysed. The anti-adipogenic mechanism of exopolysaccharide (EPS) isolated from L-14 extract was also analysed using Toll-like receptor 2 (TLR2) inhibitor C29. RESULTS: L-14 extract inhibited 3T3-L1 and hBM-MSC differentiation into mature adipocytes by upregulating AMPK signalling pathway in the early stage of adipogenic differentiation. The weight of the HFD + L-14 group (31.51 ± 1.96 g) was significantly different from that of the HFD group (35.14 ± 3.18 g). L-14 extract also significantly decreased the serum triacylglycerol/high-density lipoprotein cholesterol ratio (an insulin resistance marker) and steatohepatitis. In addition, EPS activated the AMPK signalling pathway by interacting with TLR2, consequently inhibiting adipogenesis. CONCLUSIONS: EPS from L-14 extract inhibits adipogenesis via TLR2 and AMPK signalling pathways, and oral intake of L-14 extract improves obesity and obesity-associated diseases in vivo. Therefore, EPS can be used to prevent and treat obesity and metabolic disorders.

Enterococcus faecium L-15 Extract Enhances the Self-Renewal and Proliferation of Mouse Skin-Derived Precursor Cells.

Lactic acid bacteria (LAB) in the gastrointestinal tract have beneficial health effects. LAB activate the proliferation of intestinal stem cells and speed the recovery of damaged intestinal cells, but little is known about effect of LAB on other adult stem cells. In this study, a cell-free extract of Enterococcus faecium L-15 (L15) was exposed to mouse skin-derived precursor cells (SKPs), and the changes in characteristics associated with proliferation and self-renewal capacity were investigated. L15 increased the size of the spheres and the proliferation rate of SKPs. Cell cycle analysis revealed that cells in the S-phase increased after treatment with L15. In the L15-treated group, the total number of spheres significantly increased. The expression level of pluripotency marker genes also increased, while the mesenchymal lineage-related differentiation marker genes significantly decreased in the L15-treated group. The PI3K/Akt signaling pathway was activated by L15 in SKPs. These results indicate that L15 enhances proliferation and self-renewal of SKPs and may be used as a supplement for stem cell maintenance or application of stem cell therapy. This is the first report to investigate the functional effects of E. faecium on the proliferation and self-renewal capacity of SKPs.

Insulin-like growth factor 2 promotes osteogenic cell differentiation in the parthenogenetic murine embryonic stem cells.

Embryonic stem cells (ESCs) are pluripotent and can differentiate into all somatic cell types. ESCs are an alternative solution to hard tissue regeneration and skeletal tissue repair to treat bone diseases and defects using regenerative strategies. Parthenogenetic ESCs (PESCs) may be a useful alternative stem cell source for tissue repair and regeneration. The defects in full-term development of this cell type enable researchers to avoid the ethical concerns related to ESC research. Moreover, in female patients, if the PESCs are derived from oocytes, then they will have that patient's genetic information. Here, we present data demonstrating that osteogenic differentiation of PESCs can be promoted by insulin-like growth factor 2 (IGF2). PESCs were plated onto Petri dishes with ESC culture medium supplemented with or without IGF2, followed by culturing of the cells for 1 week. PESCs formed floating aggregates called embryoid bodies (EBs). An osteogenic lineage was induced from the EBs by incubating them in medium containing serum, ascorbic acid, ß-glycerophosphate, and retionic acid, with or without IGF2, for 20 days. Gene expression of specific osteoblastic markers such as osteocalcin, osteopontin, osteonectin, bone sialoprotein, collagen type-I, alkaline phosphatase, and Runx2 (Cbfa-I) was analyzed by real-time polymerase chain reaction. The expression level of osteocalcin, osteopontin, osteonectin, and alkaline phosphatase was twofold higher in IGF2-treated PESC derivatives than IGF2-naive PESC derivatives. In vivo experiments were also performed using a critical-sized calvarial defect mouse model. Ten weeks after cell transplantation, more bone tissue regeneration was observed in the IGF2-treated PESC transplantation group than in IGF2-naive PESC transplantation group. Both our in vitro and in vivo data indicate that IGF2 induces osteogenic differentiation of PESCs. Addition of IGF2 may reactivate imprinting genes in PESCs that are only expressed in the paternal genome and are normally silent in PESCs. Our findings provide insights into the mechanisms of skeletal tissue repair and the imprinting mechanisms active in stem cells.