High-frequency repetitive transcranial magnetic stimulation protects against cerebral ischemia/reperfusion injury in rats: Involving the mitigation of ferroptosis and inflammation.

BACKGROUND AND AIM: Repetitive transcranial magnetic stimulation (rTMS) has been found to attenuate cerebral ischemia/reperfusion (I/R) injury. However, its effects and mechanism of action have not yet been clarified. It has been reported that cerebral I/R injury is closely associated not only with ferroptosis but also with inflammation. Hence, the current study aimed to investigate whether high-frequency rTMS attenuates middle cerebral artery occlusion (MCAO)-induced cerebral I/R injury and further to elucidate the mediatory role of ferroptosis and inflammation. METHODS: The protective effects of rTMS on experimental cerebral I/R injury were investigated using transient MCAO model rats. Neurological scores and pathological changes of cerebral ischemic cortex were assessed to evaluate the effects of rTMS on cerebral I/R injury. The involvement of ferroptosis and that of inflammation were examined to investigate the mechanism underlying the effects of rTMS. RESULTS: High-frequency rTMS remarkably rescued the MCAO-induced neurological deficits and morphological damage. rTMS treatment also increased the mRNA and protein expression of glutathione-dependent peroxidase 4, decreased the mRNA and protein levels of acyl-CoA synthetase long-chain family member 4 and transferrin receptor in the cortex. Moreover, rTMS administration reduced the cerebrospinal fluid IL-1ß, IL-6, and TNF-α concentrations. CONCLUSION: These findings implicated that high-frequency rTMS alleviates MCAO-induced cerebral I/R injury, and the underlying mechanism could involve the inhibition of ferroptosis and inflammation. Our study identifies rTMS as a promising therapeutic agent for the treatment of cerebral I/R injury. Moreover, the mechanistic insights into ferroptosis and inflammation advance our understanding of it as a potential therapeutic target for diseases beyond cerebral ischemia stroke.

Treatment of radiation-induced brain injury with bisdemethoxycurcumin.

Radiation therapy is considered the most effective non-surgical treatment for brain tumors. However, there are no available treatments for radiation-induced brain injury. Bisdemethoxycurcumin (BDMC) is a demethoxy derivative of curcumin that has anti-proliferative, anti-inflammatory, and anti-oxidant properties. To determine whether BDMC has the potential to treat radiation-induced brain injury, in this study, we established a rat model of radiation-induced brain injury by administering a single 30-Gy vertical dose of irradiation to the whole brain, followed by intraperitoneal injection of 500 µL of a 100 mg/kg BDMC solution every day for 5 successive weeks. Our results showed that BDMC increased the body weight of rats with radiation-induced brain injury, improved learning and memory, attenuated brain edema, inhibited astrocyte activation, and reduced oxidative stress. These findings suggest that BDMC protects against radiation-induced brain injury.

Itaconate alleviates ß2-microglobulin-induced cognitive impairment by enhancing the hippocampal amino-ß-carboxymuconate-semialdehyde-decarboxylase/picolinic acid pathway.

ß2-microglobulin (B2M) has been established to impair cognitive function. However, no treatment is currently available for B2M-induced cognitive dysfunction. Itaconate is a tricarboxylic acid (TCA) cycle intermediate that exerts neuroprotective effects in several neurological diseases. The amino-ß-carboxymuconate-semialdehyde-decarboxylase (ACMSD)/picolinic acid (PIC) pathway is a crucial neuroprotective branch in the kynurenine pathway (KP). The present study sought to investigate whether Itaconate attenuates B2M-induced cognitive impairment and examine the mediatory role of the hippocampal ACMSD/PIC pathway. We demonstrated that 4-Octyl Itaconate (OI, an itaconate derivative) significantly alleviated B2M-induced cognitive dysfunction and hippocampal neurogenesis impairment. OI treatment also increased the expression of ACMSD, elevated the concentration of PIC, and decreased the level of 3-HAA in the hippocampus of B2M-exposed rats. Furthermore, inhibition of ACMSD by TES-991 significantly abolished the protections of Itaconate against B2M-induced cognitive impairment and neurogenesis deficits. Exogenous PIC supplementation in hippocampus also improved cognitive performance and hippocampal neurogenesis in B2M-exposed rats. These findings demonstrated that Itaconate alleviates B2M-induced cognitive impairment by upregulation of the hippocampal ACMSD/PIC pathway. This is the first study to document Itaconate as a promising therapeutic agent to ameliorate cognitive impairment. Moreover, the mechanistic insights into the ACMSD/PIC pathway improve our understanding of it as a potential therapeutic target for neurological diseases beyond B2M-associated neurocognitive disorders.

Corticosterone induces neurotoxicity in PC12 cells via disrupting autophagy flux mediated by AMPK/mTOR signaling.

AIMS: Our previous study indicated that chronic stress caused autophagy impairment and subsequent neuron apoptosis in hippocampus. However, the mechanism underlying the stress-induced damage to neurons is unclear. In present work, we investigated whether stress-level glucocorticoids (GCs) GCs promoted PC12 cell damage via AMPK/mTOR signaling-mediated autophagy. METHODS: Chronic stress-induced PC12 cell injury model was built by treatment with high level corticosterone (CORT). Cell injury was evaluated by flow cytometry assay and transmission electron microscopy observation. RESULTS: Autophagy flux was measured based on the changes in LC3-II and P62 protein expressions, and the color alteration of mCherry-GFP-LC3-II transfection. Our results showed that CORT not only increased cell injury and apoptosis, but also dysregulated AMPK/mTOR signaling-mediated autophagy flux, as indicated by the upregulated expression of LC3-II and P62 proteins, and the lowered ration of autolysosomes to autophagosomes. Mechanistically, our results demonstrated that autophagy activation by AMPK activator metformin or mTOR inhibitor rapamycin obviously promotes cell survival and autophagy flux, improved mitochondrial ultrastructure, and reduced expression of Cyt-C and caspase-3 in CORT-induced PC12 cells. CONCLUSION: These results indicate that high CORT triggers PC12 cell damage through disrupting AMPK/mTOR-mediated autophagy flux. Targeting this signaling may be a promising approach to protect against high CORT and chronic stress-induced neuronal impairment.

[Prevalence of asymptomatic intracranial artery stenosis in middle-aged and elderly population in the community of Foshan city, Guangdong province: a cross-sectional study].

OBJECTIVE: To investigate the prevalence and risk factors of asymptomatic intracranial artery stenosis in middle-aged and elderly population in the community of Foshan city, Guangdong province. METHODS: Subjects from residential communities were chosen through Cluster sampling method. Physical data and history were collected. Serum fasting glucose, total cholesterol and triglycerides concentrations were tested with venous blood samples. Intracranial artery stenosis was diagnosed by transcranial Doppler (TCD). Data was analyzed by the software SPSS 18.0. RESULTS: 1405 subjects met the inclusive criteria, among which 163 (11.6%) were found one (7.4%) or more (4.2%) stenotic arteries, and the standardized rate was 10.3%. 9.89% of the SICA, and 3.05%, 2.29%, 1.59%, 1.38%, 0.89% of basilar artery, middle cerebral artery, anterior cerebral artery, vertebral artery, posterior cerebral artery were found stenotic respectively. Data from the age-stratified analysis showed that the prevalence in these above 70 (27.8%) was significantly higher than that under age 70 (7.5%) (P = 0.000). Single factor and logistic regression analysis demonstrated the history of diabetes mellitus and elevated systolic pressure present were significantly different between stenotic group and the non-stenotic group (P = 0.000, P = 0.000), which were the independent risk factors of asymptomatic stenosis of intracranial arteries (OR = 2.362, 95%CI: 1.194 - 4.674;OR = 1.024, 95%CI: 1.016 - 1.031). CONCLUSION: Comparatively high prevalence of asymptomatic intracranial artery stenosis in middle-aged and aged community population was found in the Southern part of China, especially among the age group above 70. History of diabetes and elevated systolic pressure seemed to be the independent risk factors of asymptomatic stenosis of intracranial arteries.