A hybrid hydrogel composed of gelatin and gold nanoparticles (GNPs) was designed to evaluate the effect of new bone formation and proves itself to be useful as an implant material for treating defected bone tissues.

No abstract

No abstract

Melatonin has potent antioxidant, analgesic, and antinociceptive properties. However, the effects of melatonin against oxidative stress-induced cytotoxicity and inflammatory mediators in human chondrocytes remain poorly understood. This study examined the effects and underlying mechanism of melatonin in hydrogen peroxide (H(2) O(2) )-stimulated human chondrocytes and rabbit osteoarthritis (OA) model. Melatonin markedly inhibited hydrogen peroxide (H(2) O(2) )-stimulated cytotoxicity, iNOS, and COX-2 protein and mRNA expression, as well as the downstream products, NO and PGE(2) . Incubation of cells with melatonin decreased H(2) O(2) -induced Sirtuin 1 (SIRT1) mRNA and protein expression. SIRT1 inhibition by sirtinol or Sirt1 siRNA reversed the effects of melatonin on H(2) O(2) -mediated induction of pro-inflammatory cytokines (NO, PGE(2) , TNF-α, IL-1β, and IL-8) and the expression of iNOS, COX-2, and cartilage destruction molecules. Melatonin blocked H(2) O(2) -induced phosphorylation of PI3K/Akt, p38, ERK, JNK, and MAPK, as well as activation of NF-κB, which was reversed by sirtinol and SIRT1 siRNA. In rabbit with OA, intra-articular injection of melatonin significantly reduced cartilage degradation, which was reversed by sirtinol. Taken together, this study shows that melatonin exerts cytoprotective and anti-inflammatory effects in an oxidative stress-stimulated chondrocyte model and rabbit OA model, and that the SIRT1 pathway is strongly involved in this effect.

No abstract

The lysyl oxidase-like 2 (LOXL2) protein is a human paralogue of lysyl oxidase (LOX) that functions as an amine oxidase for formation of lysine-derived cross-links found in collagen and elastin. In addition to the C-terminal domains characteristic to the LOX family members, LOXL2 contains four scavenger receptor cysteine-rich (SRCR) domains in the N-terminus. In order to assess the amine oxidase activity of LOXL2, we expressed a series of recombinant LOXL2 proteins with deletions in the SRCR domains, using an Escherichia coli expression system. All of the purified recombinant LOXL2 proteins, with or without the SRCR domains in the N-terminus, showed significant amine oxidase activity toward several different types of collagen and elastin in in vitro amine oxidase assays, indicating deletion of the SRCR domains does not interfere with amine oxidase activity of LOXL2. Further, amine oxidase activity of LOXL2 was not susceptible to inhibition by β-aminopropionitrile, an irreversible inhibitor of LOX, suggesting a different enzymatic mechanism between these two paralogues.

We compared the therapeutic effects and mechanism of transplanted human dental pulp stem cells (hDPSCs) and human bone marrow-derived mesenchymal stem cells (hBM-MSCs) in a rat stroke model and an in vitro model of ischemia. Rats were intravenously injected with hDPSCs or hBM-MSCs 24 h after middle cerebral artery occlusion (MCAo), and both groups showed improved functional recovery and reduced infarct volume versus control rats, but the hDPSC group showed greater reduction in infarct volume than the hBM-MSC group. The positive area for the endothelial cell marker was greater in the lesion boundary areas in the hDPSC group than in the hBM-MSC group. Administration of hDPSCs to rats with stroke significantly decreased reactive gliosis, as evidenced by the attenuation of MCAo-induced GFAP + /nestin + and GFAP + /Musashi-1 + cells, compared with hBM-MSCs. In vivo findings were confirmed by in vitro data illustrating that hDPSCs showed superior neuroprotective, migratory, and in vitro angiogenic effects in oxygen-glucose deprivation (OGD)-injured human astrocytes (hAs) versus hBM-MSCs. Comprehensive comparative bioinformatics analyses from hDPSC-and hBM-MSC-treated in vitro OGD-injured hAs were examined by RNA sequencing technology. In gene ontology and KEGG pathway analyses, significant pathways in the hDPSC-treated group were the MAPK and TGF-b signaling pathways. Thus, hDPSCs may be a better cell therapy source for ischemic stroke than hBM-MSCs.

No abstract