FTO inhibits oxidative stress by mediating m6A demethylation of Nrf2 to alleviate cerebral ischemia/reperfusion injury.

Current therapies are of limited efficacy in cerebral ischemia/reperfusion (I/R) injury. Based on the important role of oxidative stress in cerebral I/R injury, this study aimed to explore how the N6-adenosine methylation (m6A) demethylase FTO affects oxidative stress. Middle cerebral artery occlusion/reperfusion (MCAO/R)-induced rat model and oxygen and glucose deprivation/re-oxygenation (OGD/R)-induced SH-SY5Y cells were established as in vivo and in vitro model, respectively. The neurological score of rats was measured, and the volume of cerebral infarction was measured by TTC staining. The levels of FTO, nuclear factor-erythroid 2-related factor (Nrf2), and the activity of m6A demethylase FTO were detected. The m6A methylation level of Nrf2 mRNA was detected by MeRIP experiment. Flow cytometry and MTT assay were used to detect apoptosis and proliferation in vitro. TUNEL assay was used to detect apoptosis in brain tissues. FTO and Nrf2 expressions were decreased in the MCAO/R rat brain tissues and OGD/R SH-SY5Y cells, while the m6A methylation level of Nrf2 mRNA was significantly increased. Overexpression of FTO upregulated Nrf2 expression by decreasing the m6A methylation level of Nrf2 mRNA. m6A binding protein YT521-B homology (YTH) domain family protein 2 (YTHDF2) promoted the degradation of Nrf2 by promoting the m6A methylation level of Nrf2 mRNA. Furthermore, SH-SY5Y cell apoptosis was increased and cell viability was decreased after the addition of methyltransferases METTL 3/14, thus blocking FTO to protect SH-SY5Y cells from oxidative stress injury. In vivo, overexpression of FTO decreased the area of cerebral ischemia infarction and the extent of cell apoptosis. In conclusion, FTO increases Nrf2 expression by mediating m6A demethylation of Nrf2 mRNA, thereby inhibiting oxidative stress response and ultimately alleviating cerebral I/R injury.

Antioxidant Effects of Roasted Licorice in a Zebrafish Model and Its Mechanisms.

Licorice (Gan-Cao, licorice) is a natural antioxidant and roasted licorice is the most common processing specification used in traditional Chinese medicine prescriptions. Traditional Chinese medicine theory deems that the honey-roasting process can promote the efficacy of licorice, including tonifying the spleen and augmenting "Qi" (energy). The antioxidant activity and mechanisms underlying roasted licorice have not yet been reported. In this study, we found that roasted licorice could relieve the oxidative stress injury induced by metronidazole (MTZ) and could restrain the production of excessive reactive oxygen species (ROS) induced by 2,2'-azobis (2-methylpropionamidine) dihydrochloride (AAPH) in a zebrafish model. It was further found that roasted licorice could exert its oxidative activity by upregulating the expression of key genes such as heme oxygenase 1 (HO-1), NAD(P)H quinone dehydrogenase 1 (NQO1), glutamate-cysteine ligase modifier subunit (GCLM), and glutamate-cysteine ligase catalytic subunit (GCLC) in the nuclear factor erythroid 2-related factor 2 (NRF2) signaling pathway both in vivo and in vitro. Furthermore, consistent results were obtained showing that rat serum containing roasted licorice was estimated to reduce cell apoptosis induced by H2O2. Then, the UHPLC-Q-Exactive Orbitrap MS analysis results elucidated the chemical composition of rat plasma containing roasted licorice extracts, including ten prototype chemical components and five metabolic components. Among them, six compounds were found to have binding activity with Kelch-like ECH-associated protein 1 (KEAP1), which plays a crucial role in the transcriptional activity of NRF2, using a molecular docking simulation. The results also showed that liquiritigenin had the strongest binding ability with KEAP1. Immunofluorescence further confirmed that liquiritigenin could induce the nuclear translocation of NRF2. In summary, this study provides a better understanding of the antioxidant effect and mechanisms of roasted licorice, and lays a theoretical foundation for the development of a potential antioxidant for use in clinical practice.

SLC20A2-related primary familial brain calcification with purely acute psychiatric symptoms: a case report.

BACKGROUND: Primary familial brain calcification (PFBC) is a rare inherited neurological disorder characterized by bilateral basal ganglia calcification with a series of motor and nonmotor symptoms. Mutations in the SLC20A2 gene, encoding the PiT2 protein, are the major cause of the disease. Here, we report a Chinese PFBC family carrying a SLC20A2 gene mutation, and the proband presented with purely acute psychiatric symptoms, which has been rarely reported in this disease. CASE PRESENTATION: A 38-year-old woman was hospitalized due to disorganized speech; disordered thought contents; disorganized behaviour; emotional instability and lability; and grandiose words, actions and facial expressions. Brain computerized tomography (CT) revealed calcification in the basal ganglia; cerebellar dentate nuclei; and subcortical, periventricular, and deep white matter regions in she and her family members. Through mutation analysis, a heterozygous truncating mutation, c.1723G > T, p.(Glu575*), was identified in the SLC20A2 gene in this family. Thus, this patient was diagnosed with genetically confirmed PFBC, and she responded well to a low dose of antipsychotic drugs. The penetrance of the disease in this family was only 33%, which was significantly lower than that in most families carrying SLC20A2 gene mutations. CONCLUSIONS: Patients with SLC20A2-related PFBC might present with psychiatric symptoms alone, and the penetrance of the disease may be quite low, which adds to the clinical heterogeneity of the disease.

Expression and function of cathepsin B-like proteinase in larval hemocytes of Helicoverpa armigera during metamorphosis.

Previous work has revealed that Helicoverpa armigera cathepsin B-like proteinase (HCB) is expressed in oocytes as well as fat bodies of pupae and adults. It plays key roles in the degradation of yolk proteins during embryogenesis and the decomposition of adult fat bodies of H. armigera. This study investigated the expression and function of HCB in larval hemocytes during larva-pupa metamorphosis. Results showed that the expression of HCB in hemocytes exhibited developmental stage specificity. No HCB was found in hemocytes from 5th-molting larvae. On the contrary, HCB was highly transcribed in the hemocytes from 6th-48-h larvae. Besides, it was abundantly translated in 6th-96-h larvae (prepupation). HCB is mainly expressed in plasmatocytes and granulocytes at both transcriptional and translational levels. The number of plasmatocytes and granulocytes markedly increased before pupation. In addition, hemocytes distributed in hematopoietic organs at early larval stage, then migrated to midgut and fat bodies that would undergo histolysis at later larval stage. These findings suggested that HCB is expressed in H. armigera larval hemocytes and involved in larva-pupa metamorphosis.