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Background A large amount of iron deposition in the brain can cause neuronal damage by inducing oxidative stress, neuroinflammation, and abnormal mitochondrial function. In addition, iron deposition is also reported to be closely related to the pathogenesis of Alzheimer's disease (AD). The neurofibrillary tangles aggregated by tau hyperphosphorylation are one of the important pathological features of AD. Objective To investigate potential effect of exogenous trivalent iron ions on neuronal activity in human neuroblastoma (SH-SY5Y) cells and tau hyperphosphorylation and aggregation. Methods SH-SY5Y cells were treated with ferric chloride (FeCl3) at four concentrations (10, 100, 200, and 400 mg·L−1). Cell survival rate was then detected by CCK8 assay. Intracellular iron content was determined prussian blue (Perl's) by iron staining after 24 h exposure to FeCl3 at 10 or 200 mg·L−1. Transfection of tau-P301L plasmid was conducted to construct an AD-like cell model for tau overexpression. The differences in the expression of the phosphorylated tau (p-tau) protein in SH-SY5Y cells and SH-SY5Y cells with tau overexpression were detected by Western blotting after 24 h exposure to FeCl3 at 10 and 200 mg·L−1. After dilution with phosphate buffered saline (PBS), FeCl3, human tauR3, and FeCl3 + tauR3 were incubated at 37℃, and the fluorescence intensity reflecting tau aggregation level was measured by thioflavin T(ThT) method at 12, 24, 36, 48, 60, 72, 84, and 96 h, respectively. Meanwhile, after 96 h coincubation of FeCl3 and tauR3, the fibers formed by tau aggregation were observed under a transmission electron microscope (TEM). Results After 24 h of FeCl3 exposure, the cell survival rate of SH-SY5Y cells among all groups was statistically different (F=8.63, P<0.01). The cell survival rates in the 200 and 400 mg·L−1 groups were 80.1% and 68.7% of the control group, respectively (P<0.05). Compared with the control group, the nuclei of the 200 mg·L−1 FeCl3 group were mainly yellowish-brown after iron staining and the positive cell rate was up-regulated by 12.9% (P<0.01). After 24 h of FeCl3 exposure , the p-tau (Ser396) protein expression was statistically different among all groups (F=11.6, P<0.01). Compared with the control group, the p-tau protein expression level of SH-SY5Y cells in the 200 mg·L−1 group was up-regulated by 72.7% (P<0.01). After FeCl3-treated SH-SY5Y cells with tau overexpression for 24 h, the p-tau (Ser396) protein expression was statistically different among all groups (F=27.8, P<0.01). Compared with the tau group, the p-tau (Ser396) protein expression level of SH-SY5Y cells in the tau + 200 mg·L−1 group was up-regulated by 44.6% (P<0.05). Compared with the tauR3 group, the fluorescence intensities in the 84 and 96 h tauR3 + FeCl3 groups were up-regulated by 49.9% and 53.7% (P<0.01) respectively. After 96 h of coincubation, compared with the tauR3 group, FeCl3 + tauR3 aggravated tau aggregation and formed fiber deposition under TEM. Conclusion Exogenous trivalent iron ions may inhibit SH-SY5Y cell viability, promote the phosphorylation of tau in SH-SY5Y cells transfected with tau-P301L plasmid, and aggravate tauR3 aggregation and fiber production.
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Background Occupational and environmental particulate matter may cause fibrosis, accompanied by RNA m6A modification changes. Neodymium oxide (Nd2O3) can cause mouse lung fibrosis, which contains a large number of fibroblasts. Objective To investigate m6A modification of tumor necrosis factor receptor-associated protein 6/nuclear factor-κB (TRAF6/NF-κB) signaling pathway in fibrosis of human embryonic lung fibroblasts induced by Nd2O3, and identify the key m6A modification sites of TRAF6. Methods Designed concentrations of Nd2O3 (0, 1.563, 3.125, 6.25, 12.5, 25, 50, 100, and 200 mg∙L−1) were infected with HELF cells for 24 and 48 h, and cell viability was detected to determine exposure time and dose. Measurements included indicators of fibrosis [hydroxyproline (HYP) and transforming growth factor-β1 (TGF-β1)], m6A methylation level, methyltransferases (METTL3 and METTL14), demethylases (FTO and ALKBH5), reading proteins (YTHDC2 and YTHDF2), fibrosis-associated genes (collagen-І, vimentin, and α-SMA), and proteins related to signaling pathway (TRAF6, NFKB1, P65, and P-P65). The enrichment of m6A in TRAF6 mRNA was measured by methylated RNA immunoprecipitation-quantitative real-time PCR (MeRIP-qPCR). Results The results of cell viability indicated that 6.25, 12.5, 25 mg∙L−1 Nd2O3 and 48 h exposure time were used for subsequent experiments. After 48 h exposure, compared with the control group, the HYP level in the 25 mg∙L−1 Nd2O3 group was increased, and the levels of TGF-β1 in the 6.25, 12.5, and 25 mg∙L−1 Nd2O3 groups were increased (P<0.05); the overall m6A methylation levels of HELF cells in the 12.5 and 25 mg∙L−1 Nd2O3 groups were increased (P<0.05). At mRNA level, compared with the control group, the mRNA expression levels of methyltransferases METTL3 and METTL14 (6.25, 12.5, and 25 mg∙L−1 Nd2O3) were increased (P<0.05); the mRNA expression level of reading protein YTHDF2 (6.25, 12.5, and 25 mg∙L−1 Nd2O3) was increased (P<0.05), while the mRNA expression level of YTHDC2 (25 mg∙L−1 Nd2O3) was decreased (P<0.05); the mRNA expression levels of demethylases FTO (12.5 and 25 mg∙L−1 Nd2O3) and ALKBH5 (25 mg∙L−1 Nd2O3) were decreased (P<0.05); the mRNA expression levels of fibrosis-related genes vimentin, α-SMA, and collagen-Ⅰ (6.25, 12.5, and 25 mg∙L−1 Nd2O3) were increased (P<0.05); the mRNA expression levels of pathway-related genes TRAF6 (25 mg∙L−1 Nd2O3) and NFKB1 (12.5 and 25 mg∙L−1 Nd2O3) were increased (P<0.05). At protein level, compared with the control group, the expression levels of methyltransferases METTL3 (25 mg∙L−1 Nd2O3) and METTL14 (12.5 and 25 mg∙L−1 Nd2O3) were increased (P<0.05); the expression level of reading protein YTHDF2 (12.5 and 25 mg∙L−1 Nd2O3) was increased, while the expression level of YTHDC2 (25 mg∙L−1 Nd2O3) was decreased (P<0.05); the expression level of demethylase FTO (25 mg∙L−1 Nd2O3) was decreased (P<0.05); the expression level of fibrosis-associated protein vimentin was increased at 25 mg∙L−1 Nd2O3, and the expression levels of α-SMA and collagen-Ⅰ were increased at 12.5 and 25 mg∙L−1 Nd2O3 (P<0.05); the expression levels of TRAF6 and P-P65 were increased at 25 mg∙L−1 Nd2O3 (P<0.05). The MeRIP-qPCR results showed that compared with the control group, the concentrations of m6A in all Nd2O3 groups were significantly increased (P<0.05). Conclusions Upon exposure of HELF cells to Nd2O3, the alterations in fibrosis-related indexes increase the expression of some m6A methylases and decrease the expression of demethylases, thereby increasing the m6A methylase level, and may promote the progression of fibrosis by activating the TRAF6/NF-κB signaling pathway.
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As a reversible and dynamic epigenetic marker, N6-adenylate methylation (m6A) modification is the most common mRNA modification in eukaryotes. This paper briefly described how m6A can influence RNA splicing, stability, and translation after transcription, and then participate in a variety of signaling pathways and biological and pathological processes, regulating cell proliferation, apoptosis, epithelial mesenchymal transformation (EMT) processes, and tumor invasion and metastasis. In addition, according to current studies, m6A methyltransferases (writers) are believed to promote EMT and tumor development, and readers and erasers both promote and inhibit EMT in different research objects. In this review, we summarized the mechanism of m6A modification and its role in cell transformation, and pointed out the direction of disease treatment.
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Objective To investigate the clinical efficacy of microendoscopic discectomy(MED) and fanestration discectomy (FD) for treating single segement lumbar disc herniation(LDH).Methods A total of 168 patients with single segment LDH were included in this retrospective study from April 2009 to Janurary 2012.The patients were divided into MED group(81 cases) and FD group(87 cases) according to surgery mode.The operation and hospitalization indexes for each group were collected and compared respectively.The clinical outcomes were evaluated by the visual analogue scale(VAS),Japanese Orthopedic Association(JOA) scores and Oswestry Disability Index(ODD.Lumbar curves(Cobb's angle),intervertebral space height,horizontal displacement and angular displacement before and after surgery were applied to evaluate the lumbar spinal stability.Results The skin incision length,amount of intraoperative blood loss,operation time and hospitalization duration in the MED group were less than that in the FD group(P＜0.05).All cases completed follow up for more than 4 years.The each item score at last follow up in the two groups was significantly improved compared with before operation(P＜0.05),the inter-group comparison had no statistical difference(P＞0.05).The postoperative lumbar curve and intervertebral space height were decreased in both groups.The postoperative lumbar curve in the FD group was decreased compared with the MED.One case in the MED group and 3 cases in the FD group appeared lumbar vertebral instability.Conclusion Both MED and FD for treating single segment LDH can gain better clinical effect,MED has short operation time,small trauma and little influence on lumbar vertebral stability,and is an effective minimal invasive surgery.
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Objective To compare the clinical outcome of internal fixation(IF)and total hip arthroplasty (THA)for the elderly patients with displaced femoral neck fracture. Methods A total of 128 patients with dis-placed femoral neck fracture admitted from January 2010 to December 2012 were selected and divided into IF group(61 cases)and THA group(67 cases). The operation and hospitalization index were compared between the 2 groups. All patients underwent follow-ups after operation. The functional recovery scale for hip fracture (FRS) and EQ-5D index were applied to evaluate the clinical outcomes periodically. Results Compared to THA group, the intraoperative trauma ,operation time and bed days were less in IF group(P0.05). Follow-ups at all time points revealed hip function in THE group is better than that in IF group(P 0.05). Within 3 years,the costs related to fracture were 41772 yuan for IF group and 61174 yuan for THA group respectively. Conclusion Both internal fixation and total hip arthroplasty can provide satisfactory outcome for elderly patients with displaced femoral neck fracture. Compared with IF ,THA causes bigger trauma and costs more ,but ends up with lower complication incidences ,and improve hip function in a shorter period.
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Objective To evaluate the mid‐term efficacy of microendoscopic discectomy (MED) and microsurgical lumbar discectomy (MSLD) for treating lumbar disc herniation (LDH) .Methods 98 patients with single segment LDH in the Orthopedic department of the Second Hospital of Lanzhou University from March 2009 to April 2010 were divided into 2 groups ,including 44 cases undergoing MED and 54 cases undergoing MSLD .The operative efficacies were assessed by the visual analogue scale (VAS) , Japanese Orthopedic Association (JOA) scores and Oswestry Disability Index (ODI) .Results There were statistically significant differences in the skin incision length ,amount of intraoperative blood loss and time of returning to work between the two groups (P0 .05) .The mean follow‐up duration was 49 .13 months in the MED group and 47 .24 months in the MSLD group respectively .At the last follow‐up the postoperative back and leg pain VAS scores ,JOA scores and ODI in each group were signifi‐cantly improved compared with the preoperative data (P<0 .01) .However ,there were no statistically significant differences in the intergroup comparison .Conclusion MED and MSLD are the effective methods for treating single segment LDH .However ,MED has less trauma and early out‐of‐bed ambulation ,is an ideal minimally invasive surgery .