While N6-methyladenosine (m6A), the most abundant internal modification in eukaryotic mRNA, is linked to cell differentiation and tissue development, the biological significance of m6A modification in mammalian glial development remains unknown. Here, we identify a novel m6A reader, Prrc2a (Proline rich coiled-coil 2 A), which controls oligodendrocyte specification and myelination. Nestin-Cre-mediated knockout of Prrc2a induces significant hypomyelination, decreased lifespan, as well as locomotive and cognitive defects in a mouse model. Further analyses reveal that Prrc2a is involved in oligodendrocyte progenitor cells (OPCs) proliferation and oligodendrocyte fate determination. Accordingly, oligodendroglial-lineage specific deletion of Prrc2a causes a similar phenotype of Nestin-Cre-mediated deletion. Combining transcriptome-wide RNA-seq, m6A-RIP-seq and Prrc2a RIP-seq analysis, we find that Olig2 is a critical downstream target gene of Prrc2a in oligodendrocyte development. Furthermore, Prrc2a stabilizes Olig2 mRNA through binding to a consensus GGACU motif in the Olig2 CDS (coding sequence) in an m6A-dependent manner. Interestingly, we also find that the m6A demethylase, Fto, erases the m6A modification of Olig2 mRNA and promotes its degradation. Together, our results indicate that Prrc2a plays an important role in oligodendrocyte specification through functioning as a novel m6A reader. These findings suggest a new avenue for the development of therapeutic strategies for hypomyelination-related neurological diseases.

Nitric oxide (NO) regulates diverse cellular signaling through S-nitrosylation of specific Cys residues of target proteins. The intracellular level of S-nitrosoglutathione (GSNO), a major bioactive NO species, is regulated by GSNO reductase (GSNOR), a highly conserved master regulator of NO signaling. However, little is known about how the activity of GSNOR is regulated. Here, we show that S-nitrosylation induces selective autophagy of Arabidopsis GSNOR1 during hypoxia responses. S-nitrosylation of GSNOR1 at Cys-10 induces conformational changes, exposing its AUTOPHAGY-RELATED8 (ATG8)-interacting motif (AIM) accessible by autophagy machinery. Upon binding by ATG8, GSNOR1 is recruited into the autophagosome and degraded in an AIM-dependent manner. Physiologically, the S-nitrosylation-induced selective autophagy of GSNOR1 is relevant to hypoxia responses. Our discovery reveals a unique mechanism by which S-nitrosylation mediates selective autophagy of GSNOR1, thereby establishing a molecular link between NO signaling and autophagy.

Although post-ischemic inflammation induced by the innate immune response is considered an essential step in the progression of cerebral ischemia injury, the role of triggering receptor expressed on myeloid cells 2 (TREM2) in the pathogenesis of ischemic stroke remains to be elucidated. Here, we found that the transcriptional and post-transcriptional levels of TREM2 were increased in cultured primary microglia after oxygen-glucose deprivation and reoxygenation and in the ischemic penumbra of the cerebral cortex after middle cerebral artery occlusion (MCAO) and reperfusion in mice. TREM2 was mainly expressed in microglia, but not in astrocytes, neurons, or oligodendrocytes in mice subjected to MCAO. Manipulating TREM2 expression levels in vitro and in vivo significantly regulated the production of pro-and anti-inflammatory mediators after ischemic stroke. TREM2 overexpression markedly suppressed the inflammatory response and neuronal apoptosis. By contrast, TREM2 gene silencing intensified the inflammatory response, increased neuronal apoptosis and infarct volume, and further exacerbated neurological dysfunction. Our study demonstrated that TREM2 protects against cerebral ischemia/ reperfusion injury through the aspect of post-ischemic inflammatory response and neuronal apoptosis. Pharmacological targeting of TREM2 to suppress the inflammatory response may provide a new approach for developing therapeutic strategies in the treatment of ischemic stroke and other cerebrovascular diseases.

Oxidative stress is involved in a variety of diseases. Prospective studies investigating the relationship between oxidative stress biomarkers and the status and development of colorectal cancer (CRC) are scarce; previous studies have failed to establish a relationship between the serum total oxidant/antioxidant status and CRC. Therefore, we compared the total serum oxidant/antioxidant levels of CRC patients and healthy subjects, and analyzed their clinical significance in the CRC. Fasting blood samples from 132 CRC patients and 64 healthy subjects were collected. Oxidative stress parameters, including total oxidant status (TOS) and total antioxidant status (TAS), were measured, and the oxidative stress index (OSI) was calculated. The TOS and OSI levels increased significantly (P<0.001) and the TAS level significantly decreased (P<0.001) in the CRC group compared to those in the healthy control group. Oxidative stress parameters differed significantly depending on the patient’s smoking and drinking status (P<0.05). The preoperative and postoperative levels of TOS, TAS, and OSI did not differ significantly between primary sites (colon/rectum) and clinical stages (P>0.05).However, the levels of TOS, TAS, and OSI were significantly different between patients with no metastasis and those with metastases to two organs (P<0.05) Finally, the parameters are affected by smoking and drinking, and subsequent research should be conducted excluding the relevant influencing factors.

Although food availability is a potent synchronizer of the peripheral circadian clock in mammals, the underlying mechanisms are unclear. Here, we show that hepatic Bmal1, a core transcription activator of the molecular clock, is post-transcriptionally regulated by signals from insulin, an important hormone that is temporally controlled by feeding. Insulin promotes postprandial Akt-mediated Ser42-phosphorylation of Bmal1 to induce its dissociation from DNA, interaction with 14-3-3 protein and subsequently nuclear exclusion, which results in the suppression of Bmal1 transcriptional activity. Inverted feeding cycles not only shift the phase of daily insulin oscillation, but also elevate the amplitude due to food overconsumption. This enhanced and reversed insulin signalling initiates the reset of clock gene rhythms by altering Bmal1 nuclear accumulation in mouse liver. These results reveal the molecular mechanism of insulin signalling in regulating peripheral circadian rhythms.

In this study, the protective effect of melatonin on kainic acid (KA)-induced neurotoxicity involving autophagy and α-synuclein aggregation was investigated in the hippocampus of C57/BL6 mice. Our data showed that intraperitoneal injection of KA (20 mg/kg) increased LC3-II levels (a hallmark protein of autophagy) and reduced mitochondrial DNA content and cytochrome c oxidase levels (a protein marker of mitochondria). Atg7 siRNA transfection prevented KA-induced LC3-II elevations and mitochondria loss. Furthermore, Atg7 siRNA attenuated KA-induced activation of caspases 3/12 (biomarkers of apoptosis) and hippocampal neuronal loss, suggesting a pro-apoptotic role of autophagy in the KA-induced neurotoxicity. Nevertheless, KA-induced α-synuclein aggregation was not affected in the Atg7 siRNA-transfected hippocampus. The neuroprotective effect of melatonin (50 mg/kg) orally administered 1 hr prior to KA injection was studied. Melatonin was found to inhibit KA-induced autophagy-lysosomal activation by reducing KA-induced increases in LC3-II, lysosomal-associated membrane protein 2 (a biomarker of lysosomes) and cathepsin B (a lysosomal cysteine protease). Subsequently, KA-induced mitochondria loss was prevented in the melatonin-treated mice. At the same time, melatonin reduced KA-increased HO-1 levels and α-synuclein aggregation. Our immunoprecipitation study showed that melatonin enhanced ubiquitination of α-synuclein monomers and aggregates. The anti-apoptotic effect of melatonin was demonstrated by attenuating KA-induced DNA fragmentation, activation of caspases 3/12, and neuronal loss. Taken together, our study suggests that KA-induced neurotoxicity may be mediated by autophagy and α-synuclein aggregation. Moreover, melatonin may exert its neuroprotection via inhibiting KA-induced autophagy and a subsequent mitochondrial loss as well as reducing α-synuclein aggregation by enhancing α-synuclein ubiquitination in the CNS.

The brain is the major dose-limiting organ in patients undergoing radiotherapy for assorted conditions. Radiation-induced brain injury is common and mainly occurs in patients receiving radiotherapy for malignant head and neck tumors, arteriovenous malformations, or lung cancer-derived brain metastases. Nevertheless, the underlying mechanisms of radiation-induced brain injury are largely unknown. Although many treatment strategies are employed for affected individuals, the effects remain suboptimal. Accordingly, animal models are extremely important for elucidating pathogenic radiation-associated mechanisms and for developing more efficacious therapies. So far, models employing various animal species with different radiation dosages and fractions have been introduced to investigate the prevention, mechanisms, early detection, and management of radiation-induced brain injury. However, these models all have limitations, and none are widely accepted. This review summarizes the animal models currently set forth for studies of radiation-induced brain injury, especially rat and mouse, as well as radiation dosages, dose fractionation, and secondary pathophysiological responses.

Highlights d Per2 inhibits mTORC1 signaling in the cytoplasm d Per2 recruits Tsc1 to mTORC1 to suppress its activity in a Rheb-independent manner d Per2 reduces de novo protein synthesis but enhances autophagy d During fasting, glucagon-CREB/CRTC2 signaling induces Per2 to inhibit mTORC1 activity