Sitagliptin ameliorates advanced glycation end-product (AGE)-induced degradation of extracellular matrix in human primary chondrocytes.

Accumulation of advanced glycation end-products (AGEs) increases inflammation and triggers processes involved in the pathogenesis of osteoarthritis (OA). As a major debilitating age-related disease, it is imperative that novel therapies for OA be sought. In the present study, we investigated the effects of the selective dipeptidyl peptidase IV (DPP-4) inhibitor sitagliptin in human primary chondrocytes exposed to insult by AGEs to elucidate the potential role of sitagliptin in the treatment of OA. Our findings show that inhibition of DPP-4 by sitagliptin could reduce oxidative stress, increase cell viability and prevent degradation of type II collagen and aggrecan by matrix metalloproteinases (MMPs) and a disintegrin and metalloproteinase with thrombospondin motifs (ADAMTS) induced by AGEs in human primary chondrocytes. Mechanistically, we found that sitagliptin inhibited AGEs-induced nuclear translocation of p65 protein and drastically decreased the luciferase activity of NF-κB. These findings indicate that sitagliptin may have potential as a novel therapeutic option for the treatment and prevention of OA.

Methylprednisolone promotes recovery of neurological function after spinal cord injury: association with Wnt/ß-catenin signaling pathway activation.

Some studies have indicated that the Wnt/ß-catenin signaling pathway is activated following spinal cord injury, and expression levels of specific proteins, including low-density lipoprotein receptor related protein-6 phosphorylation, ß-catenin, and glycogen synthase kinase-3ß, are significantly altered. We hypothesized that methylprednisolone treatment contributes to functional recovery after spinal cord injury by inhibiting apoptosis and activating the Wnt/ß-catenin signaling pathway. In the current study, 30 mg/kg methylprednisolone was injected into rats with spinal cord injury immediately post-injury and at 1 and 2 days post-injury. Basso, Beattie, and Bresnahan scores showed that methylprednisolone treatment significantly promoted locomotor functional recovery between 2 and 6 weeks post-injury. The number of surviving motor neurons increased, whereas the lesion size significantly decreased following methylprednisolone treatment at 7 days post-injury. Additionally, caspase-3, caspase-9, and Bax protein expression levels and the number of apoptotic cells were reduced at 3 and 7 days post-injury, while Bcl-2 levels at 7 days post-injury were higher in methylprednisolone-treated rats compared with saline-treated rats. At 3 and 7 days post-injury, methylprednisolone up-regulated expression and activation of the Wnt/ß-catenin signaling pathway, including low-density lipoprotein receptor related protein-6 phosphorylation, ß-catenin, and glycogen synthase kinase-3ß phosphorylation. These results indicate that methylprednisolone-induced neuroprotection may correlate with activation of the Wnt/ß-catenin signaling pathway.

Proflavin suppresses the growth of human osteosarcoma MG63 cells through apoptosis and autophagy.

Proflavin is one of the novel acridine derivatives that possess various pharmacological effects. Although numerous studies have been performed to investigate proflavin, its effects have not been investigated on the human osteosarcoma MG63 cell line. The core aim of the present study was to test the effects of proflavin on the viability of MG63 cells and the induction of apoptosis and autophagy in MG63 cells. The induction of apoptosis was examined by measuring the changes in the expression of the B-cell lymphoma 2 (Bcl-2) and Bcl-2-associated X protein mRNA and proteins. Apoptotic cell death was identified by the proteolytic cleavage of poly (adenosine diphosphate-ribose) polymerase and caspase-3 and caspase-9. In addition, the autophagic effects of proflavin were examined by the quantitation of the mRNA expression of autophagy protein 5 and Beclin 1, in addition to the identification of the accumulation of microtubule-associated protein 1 light chain 3-II. The present results revealed that proflavin inhibited the proliferation of MG63 cells in a dose-dependent manner. Proflavin-induced cell death was attributed to apoptosis and autophagy. Overall, the present results indicated that the antiseptic agent proflavin exerts anticancer potential through the synergistic activity of apoptosis and autophagy.