The role of circHmbox1(3,4) in ferroptosis-mediated cognitive impairments induced by manganese.

Excessive environmental exposure to manganese (Mn) has been linked to cognitive impairments, circular RNAs (circRNAs) have been recognized for their roles in epigenetic regulation in various biological processes, including neurological pathogenesis. Previous studies found that ferroptosis, an iron ion-dependent programmed cell death, may be involved in cognitive impairments. However, specific mechanisms underlying the relationship among circRNA, ferroptosis, and neurotoxicity of Mn are not well-understood. In the current study, RNA sequencing was performed to profile RNA expression in Neuro-2a (N2a) cells that were treated with 300 µM Mn. The potential molecular mechanisms of circHmbox1(3,4) in Mn-induced cognitive impairments were investigated via various experiments, such as Western blot and intracerebroventricular injection in mice. We observed a significant decrease in the expression of circHmbox1(3,4) both in vitro and in vivo following Mn treatment. The results of Y maze test and Morris water maze test demonstrated an improvement in learning and memory abilities following circHmbox1(3,4) overexpression in Mn treated mice. Mn treatment may reduce circHmbox1(3,4) biogenesis through lowered expression of E2F1/QKI. Inhibiting circHmbox1(3,4) expression led to GPX4 protein degradation through protein ligation and ubiquitination. Overall, the current study showed that Mn exposure-induced cognitive dysfunction may be mediated through ferroptosis regulated by circHmbox1(3,4).

Circular RNA circRest regulates manganese induced cell apoptosis by targeting the mmu-miR-6914-5p/Ephb3 axis.

Overexposure to manganese (Mn) can lead to neurotoxicity, the underlying mechanisms remain incompletely understood. Circular RNAs (circRNAs) have emerged as important regulators in various biological processes. It is plausible that circRNAs may be involved in the biological mechanisms underlying Mn caused neurotoxicity. Here, circRest was downregulated in Mn-exposed mouse neuroblastoma cells (N2a cells) by RNA sequencing and quantitative real-time PCR. When circRest was overexpressed, it led to an increase in cell viability and a decrease in apoptosis following Mn exposure. Conversely, silencing circRest resulted in opposite effects in N2a cells. Further investigation revealed that circRest acts as a mmu-miR-6914-5p sponge, and mmu-miR-6914-5p could bind and inhibit Ephb3, thereby promoting apoptosis in N2a cells. This was confirmed through RNA antisense purification and dual luciferase reporter assays. Additionally, the circRest/mmu-miR-6914-5p/Ephb3 axis may influence memory and learning in mice following Mn exposure. In conclusion, our study uncovers a novel mechanism by which circRest may attenuate Mn caused neurotoxicity via the mmu-miR-6914-5p/Ephb3 axis.

Manganese-induced neurological pyroptosis: Unveiling the mechanism through the ROS activaed Caspase-3/GSDME signaling pathway.

Manganese (Mn) is an essential micronutrient in maintaining homeostasis in the human body, while excessive Mn exposure can lead to neurological disorders. To investigate whether there is an association between elevated ROS and pyroptosis caused by Mn exposure using both in vitro and in vivo models. We exposed BV2 and N2a, which represent microglial cells and Neuroblastoma cells in the brain, respectively, to different concentrations of Mn for 24 h. Following Mn exposure, we assessed cell morphology, levels of lactate dehydrogenase, and cellular ROS levels. C57BL/6 male mice were exposed to 0-100 mg/kg MnCl2·4H2O for 12 weeks through gavage. The expression level of pyroptosis proteins including caspase3 and GSDME in the hippocampus was examined. We found that Mn exposure resulted in elevated levels of cellular ROS and protein expression of Caspase3 and GSDME in both N2a and BV2 cells. The pyroptosis levels were blunted by either inhibiting Caspase3 expression or ROS production. In the in vivo model, protein levels of Caspase3 and GSDME also increased dependent of Mn concentrations. These findings suggested that neuronal pyroptosis induced by Mn exposure may occur through the ROS-stimulated Caspase3-GSDME pathway. Moreover, utilizing inhibitors targeting Caspase3 or ROS may provide protection against Mn-induced toxicity.

Long noncoding RNA Sh2d3c promotes manganese-induced neuronal apoptosis through the mmu-miR-675-5p/Chmp4b/Bax axis.

Environmental excessive manganese (Mn) exposure can cause neurotoxicity and neurodegenerative diseases. Long noncoding RNAs (lncRNAs) have been shown to affect the development of neurodegenerative diseases. However, whether lncRNAs are also linked to Mn-induced neurotoxicity has not been reported. In this study, we explored the role of lncRNAs in Mn-induced neurotoxicity and its mechanisms. LncSh2d3c was identified to be the significantly increased lncRNA in Mn-exposed N2a cells. Knockdown of lncSh2d3c increased the cell viability and inhibited cell apoptosis. Mechanistically, lncSh2d3c acted as a sponge for mmu-miR-675-5p, thereby preventing the inhibitory effect of mmu-miR-675-5p on Chmp4b. The binding potency of lncSh2d3c/mmu-miR-675-5p and mmu-miR-675-5p/Chmp4b was verified by RNA antisense purification (RAP) and luciferase reporter assays. Furthermore, we also found that the lncSh2d3c/mmu-miR-675-5p/Chmp4b/Bax axis might be associated with the learning ability and memory of mice after Mn exposure. These results revealed a novel mechanism of Mn-induced neuronal apoptosis through the lncSh2d3c/mmu-miR-675-5p/Chmp4b/Bax axis and suggested that lncSh2d3c may act as a key regulatory factor in Mn-induced neurotoxicity.

Study of Spinal Cord Substructure Expansion Margin in Esophageal Cancer.

PURPOSE: To analyze the setup errors and residual errors of different spinal cord parts in esophageal cancer patients and to explore the necessity of spinal cord segmental expansion. METHODS AND MATERIALS: Sixty cases of esophageal cancer were included with 20 patients subdivided into the following groups: neck, chest and abdomen as per the treatment site. The patients underwent intensity modulated radiation therapy (IMRT) between 2017 and 2019. Thermoplastic mask or vacuum bag were utilized for immobilization of different groups. CTVision (Siemens CT-On-Rail system) was used to acquire pre-treatment CT, and 20 consecutive pre-treatment CT datasets were collected for data analysis for each case. Images were exported to MIM (MIM Software Inc.) for processing and data analysis. Dice coefficient, maximum Hausdorff distance and centroid coordinate values between the spinal cord contours in the pre-treatment CTs and the planning CT were calculated and extracted. The contour expansion margin value is calculated as MPRV = 1.3 ∑ total + 0.5 σ total, where ∑ total and σ total are the systematic and random error, respectively. RESULTS: For neck, chest, abdominal segments of the spinal cord, the mean Dice coefficients (± SD) are 0.73 ± 0.06, 0.80 ± 0.06, 0.82 ± 0.06, the maximum Hausdorff distance residual error (± SD) are 4.46 ± 0.55, 3.49 ± 0.53, 3.46 ± 0.69 mm, and the mean centroid coordinate residual error (± SD) are 2.40 ± 0.53, 1.66 ± 0.47, 2.14 ± 0.95 mm, respectively. The calculated margin using residual centroid method in medial-lateral (ML), anterior-posterior (AP), and cranial-caudal (CC) direction of spinal cord in neck, chest, abdominal segments are 3.86, 5.37, 6.36 mm, 3.45, 3.83, 4.51 mm, 4.05, 4.83, 7.06 mm, respectively, and the calculated margin using residual Hausdorff method are 3.10, 5.33 and 6.15 mm, 3.30, 3.77, 4.61 mm, 3.35, 4.76, 6.87 mm, respectively. CONCLUSION: The setup errors and residual errors are different in each segment of the spinal cord. Different margins expansion should be applied to different segment of spinal cord.