PENK inhibits osteosarcoma cell migration by activating the PI3K/Akt signaling pathway.

BACKGROUND: This article reports the effects of proenkephalin (PENK) on osteosarcoma (OS) cell migration. METHODS: A Gene Expression Omnibus (GEO) dataset was used to identify differentially expressed genes (DEGs) in OS tumor samples and normal human osteoblasts. Tumor tissue and adjacent normal tissue were collected from 40 OS patients. MG63 cells were transfected with si-PENK. Transwell migration assays and wound healing assays were performed to compare the effect of PENK on migration. Moreover, LY294002 was used to identify the potential mechanism. Gene expression was examined via qRT-PCR and Western blotting. RESULTS: Bioinformatic analysis revealed that PENK was downregulated in OS tumor samples compared with normal human osteoblasts. Moreover, PENK was identified as the hub gene of the DEGs. The PI3K/Akt signaling pathway was significantly enriched in the DEGs. Moreover, PENK was downregulated in OS and MG63 cells compared with the corresponding control cells. Silencing PENK promoted MG63 cell migration; however, treatment with LY294002 partially attenuated PENK silencing-induced OS cell migration. CONCLUSION: PENK inhibits OS cell migration by activating the PI3K/Akt signaling pathway.

Protective effects of 3,4-dihydroxyphenylethanol on spinal cord injury-induced oxidative stress and inflammation.

3,4-Dihydroxyphenylethanol (DOPET) is a potent antioxidant polyphenolic compound. In this study, our objective was to investigate the underlying mechanism of the neuroprotective role of DOPET in attenuating spinal cord injury (SCI). Initially, SCI was induced by performing surgical laminectomy on the rats at T10-T12 level. Then, the neurological function-dependent locomotion was measured using Basso Beattie Bresnahan score, which declined in the SCI-induced group. Increased antioxidant levels such as superoxide dismutase, glutathione peroxidase, and glutathione along with other parameters such as increased lipid peroxidation (LPO) and myeloperoxidase (MPO) activities were all observed in the SCI group. Levels of proinflammatory cytokines such as tumor necrosis factor-α and interleukin-1ß were upregulated in the serum and spinal cord tissue as observed on the immunoblot. Interestingly, protein levels of apoptotic markers such as Bax, cleaved caspase 3 and RT-PCR analysis-based mRNA level of pro-inflammatory cytokine, nuclear factor- κ activated B cells (NF-κB) were significantly upregulated in the spinal cord tissue. Nonetheless, antiapoptotic factor such as B-cell lymphoma 2 (Bcl-2) protein expression was downregulated in the same group. However, on administering 10 mg/kg of DOPET, the neuronal function was rescued, antioxidants were restored back to the normal levels, LPO and MPO activities were reduced in conjunction with downregulated levels of proinflammatory cytokines and apoptotic markers in the SCI group. These findings show that DOPET could potentially target multiple signalling pathways to combat SCI.

Expression of ß-1,4-galactosyltransferase I in a surgically-induced rat model of knee osteoarthritic synovitis.

BACKGROUND: There are few reports of a biological role for glycosyltransferases in the infiltration of osteoarthritic synovitis. The aim of this research was to investigate the expression and cellular location of ß-1,4-galactosyltransferase I (ß-1,4-GalT-I) in a surgically-induced rat model of knee osteoarthritis (OA), and explore the role of ß-1,4-GalT-I in the pathogenesis of OA. METHODS: Male Sprague-Dawley rats were randomly divided into three groups: OA group, sham group and normal group. The model of OA was established in the right knees of rats by anterior cruciate ligament transaction (ACLT) with partial medial meniscectomy. Fibroblast-like synoviocytes (FLSs) obtained from normal rat synovial tissue were cultured. The expression of ß-1,4-GalT-I mRNA in the synovial tissue, articular cartilage and FLSs treated with tumor necrosis factor-α (TNF-α) were assayed by real-time PCR. Western-blotting and immunohistochemisty were used to observe the expression of ß-1,4-GalT-I at the protein level. Double immunofluorescent staining was used to define the location of the ß-1,4-GalT-I with macrophage-like synoviocytes, FLSs, neutrophils, and TNF-α in the OA synovium. The alteration of TNF-α in FLSs which were treated with lipopolysaccharide (LPS) and ß-1,4-GalT-I-Ab were detected by enzyme-linked immunosorbent assay (ELISA). RESULTS: The mRNA and protein expression of ß-1,4-GalT-I increased in synovial tissue of the OA group compared with the normal and sham groups at two and four weeks after the surgery, however, no significant difference appeared in the articular cartilage. Immunohistochemistry also indicated that the ß-1,4-GalT-I expression in OA synovium at four weeks after surgery increased sharply compared with the control group. ß-1,4-GalT-I co-localized with macrophage-like synoviocytes, FLSs, neutrophils and TNF-α in rat OA synovitis. Moreover, in vitro ß-1,4-GalT-I mRNA in FLSs was affected in a dose- and time-dependent manner in response to TNF-α stimulation. ELISA revealed that the expression of TNF-α was attenuated in FLSs in vitro when treated with anti ß-1,4-GalT-I antibody. CONCLUSION: ß-1,4-GalT-I may play an important role in the inflammation process of rat OA synovial tissue which would provide the foundation for further researching into the concrete mechanism of ß-1,4-GalT-I in OA synovitis.