Lipoxin A4 protects primary spinal cord neurons from Erastin-induced ferroptosis by activating the Akt/Nrf2/HO-1 signaling pathway.

Ferroptosis is an iron-dependent programmed cell death, which participates in the pathogenesis of spinal cord injury (SCI). Our previous study has revealed that Lipoxin A4 (LXA4) exerts a protective role in SCI. Here, we investigated whether LXA4 can protect SCI through inhibiting neuronal ferroptosis. We treated primary spinal cord neurons with Erastin (ferroptosis activator) to induce ferroptosis. Erastin treatment reduced cell viability and enhanced cell death of primary spinal cord neurons, which was rescued by ferrostatin-1 (ferroptosis inhibitor). Moreover, Erastin repressed glutathione peroxidase 4 (GPX4) expression and the levels of glutathione and cysteine in primary spinal cord neurons. Erastin also enhanced the expression of ferroptosis biomarkers (PTGS2 and ACSL4) and the levels of reactive oxygen species (ROS) in primary spinal cord neurons. The influence conferred by Erastin was effectively abolished by LXA4 treatment. Furthermore, LXA4 enhanced the protein expression of p-AKT, nuclear factor (erythroid-derived 2)-like 2 (Nrf2) and haem-oxygenase-1 (HO-1) in primary spinal cord neurons. LXA4-mediated inhibition of ferroptosis of primary spinal cord neurons was prohibited by LY294002 (AKT inhibitor), brusatol (Nrf2 inhibitor) or zinc protoporphyrin (HO-1 inhibitor). In conclusion, this work demonstrated that LXA4 exerted a neuroprotective effect in Erastin-induced ferroptosis of primary spinal cord neurons by activating the Akt/Nrf2/HO-1 signaling pathway. Thus, this work provides novel insights into the mechanisms of action of LXA4 in ferroptosis of primary spinal cord neurons and indicates that LXA4 may be a potential therapeutic agent for SCI.

Lipoxin A4 protects against spinal cord injury via regulating Akt/nuclear factor (erythroid-derived 2)-like 2/heme oxygenase-1 signaling.

Spinal cord injury (SCI) is a devastating physical trauma worldwide. The mechanisms of SCI are still not clear and the effective treatment is limited. Lipoxin A4 (LXA4) possesses anti-inflammatory and neuroprotective effects. The present study was designed to further evaluate the molecular mechanisms of LXA4-induced protective effects in a rat model of SCI. We found that LXA4 increased Basso, Beattie and Bresnahan (BBB) scores, increased mechanical paw withdrawal threshold (PWT) and paw withdrawal latency (PWL) to a radiant heat, reduced the lesion volume, decreased Bax mRNA expression and increased Bcl-2 expression after SCI. The phosphorylation of Akt and protein expression of Nrf2 and HO-1 were reduced after SCI. LXA4 treatment significantly inhibited the reduction of Akt phosphorylation and Nrf2 and HO-1 protein expression. Injection of LY294002 notably inhibited the phosphorylation of Akt, and the expression of total Akt and Nrf2 and HO-1 after SCI in LXA4-treated rats. LY294002 prohibited LXA4-induced effects after SCI. shNrf2 injection markedly decreased both Nrf2 and HO-1 expression in LXA4-treated rats after SCI. ZnPP notably decreased HO-1 expression but did not markedly affect Nrf2 expression. shNrf2 and ZnPP prohibited LXA4-induced increase of BBB scores, and PWT and PWL, decrease of lesion volume of spinal cord, reduction of Bax expression and increase of Bcl-2 expression. The results indicate that LXA4 protects against SCI through Akt/Nrf2/HO-1 signaling. The data provide novel insights into the mechanisms of LXA4-mediated neuprotective effects against SCI and suggest that LXA4 may be a potential therapeutic agent for SCI and its associated complications.

MicroRNA-635 inhibits the malignancy of osteosarcoma by inducing apoptosis.

Recent evidence has suggested that microRNAs (miRs), which are a class of non-coding RNAs, serve diverse roles in tumorigenesis. However, the role of miR­635 in osteosarcoma (OS) remains unknown. The present study revealed that miR­635 may be a tumor suppressive miR. The expression of miR­635 was significantly decreased in OS specimens. In addition, the proliferation and invasion of OS cells transfected with miR­635 may be effectively attenuated. Transfection of cells with miR­635 may further inhibit tumor growth in vivo. miR­635 may antagonize tumorigenesis of OS possibly by inducing apoptosis, as demonstrated by flow cytometric analysis and caspase­3 kinase assays. The data of the present study suggested that miR­635 may be a novel tumor suppressor and may serve as a putative diagnostic marker for patients with OS.

Genetic polymorphisms in COL18A1 influence the development of osteosarcoma.

We conducted a case-control study to investigate the association of COL18A1 D104N polymorphism in the development of osteosarcoma in a Chinese population. Between May 2012 and May 2014, 141 patients with pathologically proven osteosarcoma and 341 were selected into this study. Genotyping of COL18A1 D104N was analyzed using polymerase chain reaction (PCR) coupled with restriction fragment length polymorphism (RFLP). By logistic regression analysis, we found that individuals with the NN genotype of COL18A1 D104N were significantly associated with an increased risk of osteosarcoma when compared with the DD genotype (OR=20.97, 95% CI=2.74-933.42). In dominant model, the NN+DN genotype of COL18A1 D104N had a 1.99 fold risk of osteosarcoma when compared with the DD genotype. Moreover, the NN genotype was correlated with a 20.45 fold risk of osteosarcoma when compared with the DN+DD genotype in recessive model. However, we did not find significant interaction between COL18A1 D104N polymorphism and Enneking stage, histological subtype, tumor metastasis and tumor location of patients with osteosarcoma. In conclusion, our study suggests that the homozygous DN and NN genotypes of COL18A1 D104N were associated with the risk of osteosarcoma.