Corrigendum: miR-124 Alleviates Ischemic Stroke-Induced Neuronal Death by Targeting DAPK1 in Mice.

[This corrects the article DOI: 10.3389/fnins.2021.649982.].

Precise Encoding of Triple-Bond Raman Scattering of Single Polymer Nanoparticles for Multiplexed Imaging Application.

Stimulated Raman scattering (SRS) microscopy in combination with innovative tagging strategies offers great potential as a universal high-throughput biomedical imaging tool. Here, we report rationally tailored small molecular monomers containing triple-bond units with large Raman scattering cross-sections, which can be polymerized at the nanoscale for enhancement of SRS contrast with smaller but brighter optical nanotags with artificial fingerprint output. From this, a class of triple-bond rich polymer nanoparticles (NPs) was engineered by regulating the relative dosages of three chemically different triple-bond monomers in co-polymerization. The bonding strategy allowed for 15 spectrally distinguishable triple-bond combinations. These accurately structured nano molecular aggregates, rather than long-chain macromolecules, could establish a universal method for generating small-sized biological SRS imaging tags with high sensitivity for high-throughput multi-color biomedical imaging.

miR-214 Alleviates Ischemic Stroke-Induced Neuronal Death by Targeting DAPK1 in Mice.

BACKGROUND: Ischemic stroke induces neuronal cell death and causes brain dysfunction. Preventing neuronal cell death after stroke is key to protecting the brain from stroke damage. Nevertheless, preventative measures and treatment strategies for stroke damage are scarce. Emerging evidence suggests that microRNAs (miRNAs) play critical roles in the pathogenesis of central nervous system (CNS) disorders and may serve as potential therapeutic targets. METHODS: A photochemically induced thrombosis (PIT) mouse model was used as an ischemic stroke model. qRT-PCR was employed to assess changes in miRNAs in ischemic lesions of PIT-stroke mice and primary cultured neurons subjected to oxygen-glucose deprivation (OGD). 2,3,5-triphenyltetrazolium chloride (TTC) staining was performed to evaluate brain infarction tissues in vivo. TUNEL staining was employed to assess neuronal death in vitro. Neurological scores and motor coordination were investigated to evaluate stroke damage, including neurological deficits and motor function. RESULTS: In vivo and in vitro results demonstrated that levels of miR-124 were significantly decreased following stroke, whereas changes in death-associated protein kinase 1 (DAPK1) levels exhibited the converse pattern. DAPK1 was identified as a direct target of miR-124. N-methyl-D-aspartate (NMDA) and OGD-induced neuronal death was rescued by miR-124 overexpression. Upregulation of miR-124 levels significantly improved PIT-stroke damage, including the overall neurological function in mice. CONCLUSION: We demonstrate the involvement of the miR-124/DAPK1 pathway in ischemic neuronal death. Our results highlight the therapeutic potential of targeting this pathway for ischemic stroke.

Functions of lactate in the brain of rat with intracerebral hemorrhage evaluated with MRI/MRS and in vitro approaches.

INTRODUCTION: Lactate accumulation in the brain is caused by the anaerobic metabolism induced by ischemic damages, which always accompanies intracerebral hemorrhages (ICH). Our former findings showed that microglia's movement was always directly toward hemorrhagic center with the highest lactate concentration, and penumbra area has the largest density of compactly arrayed microglia. However, the relationship between microglia and lactate concentration has not been well documented. METHODS: Cerebral hemorrhage model was successfully achieved by injecting collagenase VII (causing stabile localized bleeding) in CPu (striatum) of SD rats. Emodin was used as a potential therapeutic for ICH. The function of the lactate was examined with in vitro culture studies. Then, the effect of lactate on the proliferation, cell survival, migration, and phagocytosis property of microglia was investigated by in vitro culture studies. RESULTS: Lactate accumulation was observed with in vivo MRS method, and its concentration was monitored during the recovery of ICH and treatment of emodin. Lactate concentration significantly increased in the core and penumbra regions of hemorrhagic foci, and it decreased after the treatment of emodin. The in vitro culture study was verified that lactate was beneficial for the proliferation, cell survival, migration, and phagocytosis property of the microglia. CONCLUSION: Results from in vitro verification study, investigations from the recovery of ICH, and treatment of emodin verify that lactate plays an important role during the recovery of ICH. This could provide a novel therapeutic approach for ICH.

Protection of melatonin against acidosis-induced neuronal injuries.

Acidosis, a common feature of cerebral ischaemia and hypoxia, plays a key role in these pathological processes by aggravating the ischaemic and hypoxic injuries. To explore the mechanisms, in this research, we cultured primary neurons in an acidic environment (potential of hydrogen [pH]6.2, 24 hours) to mimic the acidosis. By proteomic analysis, 69 differentially expressed proteins in the acidic neurons were found, mainly related to stress and cell death, synaptic plasticity and gene transcription. And, the acidotic neurons developed obvious alterations including increased neuronal death, reduced dendritic length and complexity, reduced synaptic proteins, tau hyperphosphorylation, endoplasmic reticulum (ER) stress activation, abnormal lysosome-related signals, imbalanced oxidative stress/anti-oxidative stress and decreased Golgi matrix proteins. Then, melatonin (1 × 10-4  mol/L) was used to pre-treat the cultured primary neurons before acidic treatment (pH6.2). The results showed that melatonin partially reversed the acidosis-induced neuronal death, abnormal dendritic complexity, reductions of synaptic proteins, tau hyperphosphorylation and imbalance of kinase/phosphatase. In addition, acidosis related the activations of glycogen synthase kinase-3ß and nuclear factor-κB signals, ER stress and Golgi stress, and the abnormal autophagy-lysosome signals were completely reversed by melatonin. These data indicate that melatonin is beneficial for neurons against acidosis-induced injuries.

Gender-Related Hippocampal Proteomics Study from Young Rats After Chronic Unpredicted Mild Stress Exposure.

Clinical data have shown women are more susceptible to depression. This study was performed to identify differentially regulated proteins from hippocampus in chronic unpredicted mild stress (CUMS)-exposed male and female young rats. After 7 weeks of CUMS, depressed male (M-D) and female rats (F-D) and unstressed male (M-C) and female controls (F-C) were studied. By proteomics analysis, 74 differential proteins in F-C/M-C, 79 in F-D/M-D, 77 in F-D/F-C, and 32 in M-D/M-C were found. Further, the synapse-related proteins, cytoskeleton protein tau, and stress-related kinases in hippocampus were assayed by Western blotting. F-C rats were found to have lower levels of metabotropic glutamate receptor 1 (mGluR1) and mGluR2 and higher levels of N-methyl-D-aspartate receptor 2B (NR2B), synapsin1, total tau, and dephosphorylated tau than M-C rats. Both F-D and M-D rats had lower levels of glutamate transporter SLC1α2, mGluR1, and mGluR2, and higher levels of total tau and phosphorylated tau than their controls. Compared with their controls, M-D rats had lower NR1 and higher NR2B, and F-D rats had lower NR2A, NR2B, PSD95, and synapsin1. F-C rats had higher JNK and lower phosphorylation levels of ERK at Thr202/Thr204, JNK at Thr183/Thr185, and GSK-3ß at Ser9 than M-C ones. Both M-D and F-D rats had decreased phosphorylation of ERK at Thr202/Thr204 and GSK-3ß at Ser9, and increased JNK phosphorylation at Thr183/Thr185 compared with their controls. All these data illustrate the biochemical complexity behind the genders, and may also aid in the development of more accurate treatment strategies for depression.

Validation of Remote Sensing Retrieval Products using Data from a Wireless Sensor-Based Online Monitoring in Antarctica.

Of the modern technologies in polar-region monitoring, the remote sensing technology that can instantaneously form large-scale images has become much more important in helping acquire parameters such as the freezing and melting of ice as well as the surface temperature, which can be used in the research of global climate change, Antarctic ice sheet responses, and cap formation and evolution. However, the acquirement of those parameters is impacted remarkably by the climate and satellite transit time which makes it almost impossible to have timely and continuous observation data. In this research, a wireless sensor-based online monitoring platform (WSOOP) for the extreme polar environment is applied to obtain a long-term series of data which is site-specific and continuous in time. Those data are compared and validated with the data from a weather station at Zhongshan Station Antarctica and the result shows an obvious correlation. Then those data are used to validate the remote sensing products of the freezing and melting of ice and the surface temperature and the result also indicated a similar correlation. The experiment in Antarctica has proven that WSOOP is an effective system to validate remotely sensed data in the polar region.

The design and implementation of the leaf area index sensor.

The quick and accurate acquisition of crop growth parameters on a large scale is important for agricultural management and food security. The combination of photographic and wireless sensor network (WSN) techniques can be used to collect agricultural information, such as leaf area index (LAI), over long distances and in real time. Such acquisition not only provides farmers with photographs of crops and suggestions for farmland management, but also the collected quantitative parameters, such as LAI, can be used to support large scale research in ecology, hydrology, remote sensing, etc. The present research developed a Leaf Area Index Sensor (LAIS) to continuously monitor the growth of crops in several sampling points, and applied 3G/WIFI communication technology to remotely collect (and remotely setup and upgrade) crop photos in real-time. Then the crop photos are automatically processed and LAI is estimated based on the improved leaf area index of Lang and Xiang (LAILX) algorithm in LAIS. The research also constructed a database of images and other information relating to crop management. The leaf length and width method (LAILLW) can accurately measure LAI through direct field harvest. The LAIS has been tested in several exemplary applications, and validation with LAI from LAILLW. The LAI acquired by LAIS had been proved reliable.