WGBS of embryonic gonads revealed that long non-coding RNAs in the MHM region might be involved in cell autonomous sex identity and female gonadal development in chickens

DNA methylation plays a key role in sex determination and differentiation in vertebrates. However, there are few studies on DNA methylation involved in chicken gonad development, and most focused on male hypermethylated regions (MHM). It is unclear whether there are specific differentially methylated regions (DMRs) in chicken embryonic gonads regulating sex determination and differentiation. Here, the DNA methylation maps showed that the difference of DNA methylation level between sexes was much higher at embryonic day 10 (E10) than that at embryonic day 6 (E6), and the significant differentially methylated regions at both stages were mainly distributed on the Z chromosome, including MHM1 and MHM2. The results of bisulphite sequencing PCR (BSP) and qRT-PCR showed hypomethylation of female MHM and upregulation of long non-coding RNAs (lncRNAs) whose promoter in the MHM region was consistent with the sequencing results, and similar results were in brain and muscle. In female sex-reversed gonads, the methylation pattern of MHM remained unchanged, and the expression levels of the three candidate lncRNAs were significantly decreased compared with those in females, but were significantly increased compared to males. The fluorescence in situ hybridization (FISH) results also showed that these lncRNAs were highly expressed in female embryonic gonads. The results of methyltransferase inhibitor and dual-luciferase reporter assay suggest that lncRNA expression may be regulated by DNA methylation within their promoters. Therefore, we speculated that MHM may be involved in cell-autonomous sex identity in chickens, and that lncRNAs regulated by MHM may be involved in female sexual differentiation.

Dry eye disease caused by viral infection: Past, present and future

Following viral infection, the innate immune system senses viral products, such as viral nucleic acids, to activate innate defence pathways, leading to inflammation and apoptosis, control of cell proliferation, and consequently, threat to the whole body. The ocular surface is exposed to the external environment and extremely vulnerable to viral infection. Several studies have revealed that viral infection can induce inflammation of the ocular surface and reduce tear secretion of the lacrimal gland (LG), consequently triggering ocular morphological and functional changes and resulting in dry eye disease (DED). Understanding the mechanisms of DED caused by viral infection and its potential therapeutic strategies are crucial for clinical interventional advances in DED. This review summarizes the roles of viral infection in the pathogenesis of DED, applicable diagnostic and therapeutic strategies, and potential regions of future studies.

A structural atlas of druggable sites on Nav channels

Voltage-gated sodium (Nav) channels govern membrane excitability by initiating and propagating action potentials. Consistent with their physiological significance, dysfunction, or mutations in these channels are associated with various channelopathies. Nav channels are thereby major targets for various clinical and investigational drugs. In addition, a large number of natural toxins, both small molecules and peptides, can bind to Nav channels and modulate their functions. Technological breakthrough in cryo-electron microscopy (cryo-EM) has enabled the determination of high-resolution structures of eukaryotic and eventually human Nav channels, alone or in complex with auxiliary subunits, toxins, and drugs. These studies have not only advanced our comprehension of channel architecture and working mechanisms but also afforded unprecedented clarity to the molecular basis for the binding and mechanism of action (MOA) of prototypical drugs and toxins. In this review, we will provide an overview of the recent advances in structural pharmacology of Nav channels, encompassing the structural map for ligand binding on Nav channels. These findings have established a vital groundwork for future drug development.

Linking brain activity across scales with simultaneous opto- and electrophysiology

The brain enables adaptive behavior via the dynamic coordination of diverse neuronal signals across spatial and temporal scales: from fast action potential patterns in microcircuits to slower patterns of distributed activity in brain-wide networks. Understanding principles of multiscale dynamics requires simultaneous monitoring of signals in multiple, distributed network nodes. Combining optical and electrical recordings of brain activity is promising for collecting data across multiple scales and can reveal aspects of coordinated dynamics invisible to standard, single-modality approaches. We review recent progress in combining opto- and electrophysiology, focusing on mouse studies that shed new light on the function of single neurons by embedding their activity in the context of brain-wide activity patterns. Optical and electrical readouts can be tailored to desired scales to tackle specific questions. For example, fast dynamics in single cells or local populations recorded with multi-electrode arrays can be related to simultaneously acquired optical signals that report activity in specified subpopulations of neurons, in non-neuronal cells, or in neuromodulatory pathways. Conversely, two-photon imaging can be used to densely monitor activity in local circuits while sampling electrical activity in distant brain areas at the same time. The refinement of combined approaches will continue to reveal previously inaccessible and under-appreciated aspects of coordinated brain activity.

Enhancement of endogenous midbrain neurogenesis by microneurotrophin BNN-20 after neural progenitor grafting in a mouse model of nigral degeneration

JOURNAL/nrgr/04.03/01300535-202406000-00036/inline-graphic1/v/2023-10-30T152229Z/r/image-tiff

We have previously shown the neuroprotective and pro-neurogenic activity of microneurotrophin BNN-20 in the substantia nigra of the “weaver” mouse, a model of progressive nigrostriatal degeneration. Here, we extended our investigation in two clinically-relevant ways. First, we assessed the effects of BNN-20 on human induced pluripotent stem cell-derived neural progenitor cells and neurons derived from healthy and parkinsonian donors. Second, we assessed if BNN-20 can boost the outcome of mouse neural progenitor cell intranigral transplantations in weaver mice, at late stages of degeneration. We found that BNN-20 has limited direct effects on cultured human induced pluripotent stem cell-derived neural progenitor cells, marginally enhancing their differentiation towards neurons and partially reversing the pathological phenotype of dopaminergic neurons generated from parkinsonian donors. In agreement, we found no effects of BNN-20 on the mouse neural progenitor cells grafted in the substantia nigra of weaver mice. However, the graft strongly induced an endogenous neurogenic response throughout the midbrain, which was significantly enhanced by the administration of microneurotrophin BNN-20. Our results provide straightforward evidence of the existence of an endogenous midbrain neurogenic system that can be specifically strengthened by BNN-20. Interestingly, the lack of major similar activity on cultured human induced pluripotent stem cell-derived neural progenitors and their progeny reveals the in vivo specificity of the aforementioned pro-neurogenic effect.

Mitochondrial transplantation confers protection against the effects of ischemic stroke by repressing microglial pyroptosis and promoting neurogenesis

JOURNAL/nrgr/04.03/01300535-202406000-00037/inline-graphic1/v/2023-10-30T152229Z/r/image-tiff

Transferring healthy and functional mitochondria to the lateral ventricles confers neuroprotection in a rat model of ischemia-reperfusion injury. Autologous mitochondrial transplantation is also beneficial in pediatric patients with cardiac ischemia-reperfusion injury. Thus, transplantation of functional exogenous mitochondria may be a promising therapeutic approach for ischemic disease. To explore the neuroprotective effect of mitochondria transplantation and determine the underlying mechanism in ischemic stroke, in this study we established a photo-thrombosis-induced mouse model of focal ischemia and administered freshly isolated mitochondria via the tail vein or to the injury site (in situ). Animal behavior tests, immunofluorescence staining, 2,3,5-triphenyltetrazolium chloride (TTC) staining, mRNA-seq, and western blotting were used to assess mouse anxiety and memory, cortical infarct area, pyroptosis, and neurogenesis, respectively. Using bioinformatics analysis, western blotting, co-immunoprecipitation, and mass spectroscopy, we identified S100 calcium binding protein A9 (S100A9) as a potential regulator of mitochondrial function and determined its possible interacting proteins. Interactions between exogenous and endogenous mitochondria, as well as the effect of exogenous mitochondria on recipient microglia, were assessed in vitro. Our data showed that: (1) mitochondrial transplantation markedly reduced mortality and improved emotional and cognitive function, as well as reducing infarct area, inhibiting pyroptosis, and promoting cortical neurogenesis; (2) microglial expression of S100A9 was markedly increased by ischemic injury and regulated mitochondrial function; (3) in vitro, exogenous mitochondria enhanced mitochondrial function, reduced redox stress, and regulated microglial polarization and pyroptosis by fusing with endogenous mitochondria; and (4) S100A9 promoted internalization of exogenous mitochondria by the microglia, thereby amplifying their pro-proliferation and anti-inflammatory effects. Taken together, our findings show that mitochondrial transplantation protects against the deleterious effects of ischemic stroke by suppressing pyroptosis and promoting neurogenesis, and that S100A9 plays a vital role in promoting internalization of exogenous mitochondria.

The secondary injury cascade after spinal cord injury: an analysis of local cytokine/chemokine regulation

JOURNAL/nrgr/04.03/01300535-202406000-00035/inline-graphic1/v/2023-10-30T152229Z/r/image-tiff

After spinal cord injury, there is an extensive infiltration of immune cells, which exacerbates the injury and leads to further neural degeneration. Therefore, a major aim of current research involves targeting the immune response as a treatment for spinal cord injury. Although much research has been performed analyzing the complex inflammatory process following spinal cord injury, there remain major discrepancies within previous literature regarding the timeline of local cytokine regulation. The objectives of this study were to establish an overview of the timeline of cytokine regulation for 2 weeks after spinal cord injury, identify sexual dimorphisms in terms of cytokine levels, and determine local cytokines that significantly change based on the severity of spinal cord injury. Rats were inflicted with either a mild contusion, moderate contusion, severe contusion, or complete transection, 7 mm of spinal cord centered on the injury was harvested at varying times post-injury, and tissue homogenates were analyzed with a Cytokine/Chemokine 27-Plex assay. Results demonstrated pro-inflammatory cytokines including tumor necrosis factor α, interleukin-1β, and interleukin-6 were all upregulated after spinal cord injury, but returned to uninjured levels within approximately 24 hours post-injury, while chemokines including monocyte chemoattractant protein-1 remained upregulated for days post-injury. In contrast, several anti-inflammatory cytokines and growth factors including interleukin-10 and vascular endothelial growth factor were downregulated by 7 days post-injury. After spinal cord injury, tissue inhibitor of metalloproteinase-1, which specifically affects astrocytes involved in glial scar development, increased more than all other cytokines tested, reaching 26.9-fold higher than uninjured rats. After a mild injury, 11 cytokines demonstrated sexual dimorphisms; however, after a severe contusion only leptin levels were different between female and male rats. In conclusion, pro-inflammatory cytokines initiate the inflammatory process and return to baseline within hours post-injury, chemokines continue to recruit immune cells for days post-injury, while anti-inflammatory cytokines are downregulated by a week post-injury, and sexual dimorphisms observed after mild injury subsided with more severe injuries. Results from this work define critical chemokines that influence immune cell infiltration and important cytokines involved in glial scar development after spinal cord injury, which are essential for researchers developing treatments targeting secondary damage after spinal cord injury.

Blood-brain barrier pathology in cerebral small vessel disease

ABSTRACT

Cerebral small vessel disease is a neurological disease that affects the brain microvasculature and which is commonly observed among the elderly. Although at first it was considered innocuous, small vessel disease is nowadays regarded as one of the major vascular causes of dementia. Radiological signs of small vessel disease include small subcortical infarcts, white matter magnetic resonance imaging hyperintensities, lacunes, enlarged perivascular spaces, cerebral microbleeds, and brain atrophy; however, great heterogeneity in clinical symptoms is observed in small vessel disease patients. The pathophysiology of these lesions has been linked to multiple processes, such as hypoperfusion, defective cerebrovascular reactivity, and blood-brain barrier dysfunction. Notably, studies on small vessel disease suggest that blood-brain barrier dysfunction is among the earliest mechanisms in small vessel disease and might contribute to the development of the hallmarks of small vessel disease. Therefore, the purpose of this review is to provide a new foundation in the study of small vessel disease pathology. First, we discuss the main structural domains and functions of the blood-brain barrier. Secondly, we review the most recent evidence on blood-brain barrier dysfunction linked to small vessel disease. Finally, we conclude with a discussion on future perspectives and propose potential treatment targets and interventions.

Dysregulation of RNA modification systems in clinical populations with neurocognitive disorders

ABSTRACT

The study of modified RNA known as epitranscriptomics has become increasingly relevant in our understanding of disease-modifying mechanisms. Methylation of N6 adenosine (m6A) and C5 cytosine (m5C) bases occur on mRNAs, tRNA, mt-tRNA, and rRNA species as well as non-coding RNAs. With emerging knowledge of RNA binding proteins that act as writer, reader, and eraser effector proteins, comes a new understanding of physiological processes controlled by these systems. Such processes when spatiotemporally disrupted within cellular nanodomains in highly specialized tissues such as the brain, give rise to different forms of disease. In this review, we discuss accumulating evidence that changes in the m6A and m5C methylation systems contribute to neurocognitive disorders. Early studies first identified mutations within FMR1 to cause intellectual disability Fragile X syndromes several years before FMR1 was identified as an m6A RNA reader protein. Subsequently, familial mutations within the m6A writer gene METTL5, m5C writer genes NSUN2, NSUN3, NSUN5, and NSUN6, as well as THOC2 and THOC6 that form a protein complex with the m5C reader protein ALYREF, were recognized to cause intellectual development disorders. Similarly, differences in expression of the m5C writer and reader effector proteins, NSUN6, NSUN7, and ALYREF in brain tissue are indicated in individuals with Alzheimer's disease, individuals with a high neuropathological load or have suffered traumatic brain injury. Likewise, an abundance of m6A reader and anti-reader proteins are reported to change across brain regions in Lewy bodies diseases, Alzheimer's disease, and individuals with high cognitive reserve. m6A-modified RNAs are also reported significantly more abundant in dementia with Lewy bodies brain tissue but significantly reduced in Parkinson's disease tissue, whilst modified RNAs are misplaced within diseased cells, particularly where synapses are located. In parahippocampal brain tissue, m6A modification is enriched in transcripts associated with psychiatric disorders including conditions with clear cognitive deficits. These findings indicate a diverse set of molecular mechanisms are influenced by RNA methylation systems that can cause neuronal and synaptic dysfunction underlying neurocognitive disorders. Targeting these RNA modification systems brings new prospects for neural regenerative therapies.

Tau truncation in the pathogenesis of Alzheimer's disease: a narrative review

ABSTRACT

Alzheimer's disease is characterized by two major neuropathological hallmarks-the extracellular β-amyloid plaques and intracellular neurofibrillary tangles consisting of aggregated and hyperphosphorylated Tau protein. Recent studies suggest that dysregulation of the microtubule-associated protein Tau, especially specific proteolysis, could be a driving force for Alzheimer's disease neurodegeneration. Tau physiologically promotes the assembly and stabilization of microtubules, whereas specific truncated fragments are sufficient to induce abnormal hyperphosphorylation and aggregate into toxic oligomers, resulting in them gaining prion-like characteristics. In addition, Tau truncations cause extensive impairments to neural and glial cell functions and animal cognition and behavior in a fragment-dependent manner. This review summarizes over 60 proteolytic cleavage sites and their corresponding truncated fragments, investigates the role of specific truncations in physiological and pathological states of Alzheimer's disease, and summarizes the latest applications of strategies targeting Tau fragments in the diagnosis and treatment of Alzheimer's disease.

General anesthetic agents induce neurotoxicity through astrocytes

ABSTRACT

Neuroscientists have recognized the importance of astrocytes in regulating neurological function and their influence on the release of glial transmitters. Few studies, however, have focused on the effects of general anesthetic agents on neuroglia or astrocytes. Astrocytes can also be an important target of general anesthetic agents as they exert not only sedative, analgesic, and amnesic effects but also mediate general anesthetic-induced neurotoxicity and postoperative cognitive dysfunction. Here, we analyzed recent advances in understanding the mechanism of general anesthetic agents on astrocytes, and found that exposure to general anesthetic agents will destroy the morphology and proliferation of astrocytes, in addition to acting on the receptors on their surface, which not only affect Ca2+ signaling, inhibit the release of brain-derived neurotrophic factor and lactate from astrocytes, but are even involved in the regulation of the pro- and anti-inflammatory processes of astrocytes. These would obviously affect the communication between astrocytes as well as between astrocytes and neighboring neurons, other neuroglia, and vascular cells. In this review, we summarize how general anesthetic agents act on neurons via astrocytes, and explore potential mechanisms of action of general anesthetic agents on the nervous system. We hope that this review will provide a new direction for mitigating the neurotoxicity of general anesthetic agents.

Neuroprotective effects of chaperone-mediated autophagy in neurodegenerative diseases

ABSTRACT

Chaperone-mediated autophagy is one of three types of autophagy and is characterized by the selective degradation of proteins. Chaperone-mediated autophagy contributes to energy balance and helps maintain cellular homeostasis, while providing nutrients and support for cell survival. Chaperone-mediated autophagy activity can be detected in almost all cells, including neurons. Owing to the extreme sensitivity of neurons to their environmental changes, maintaining neuronal homeostasis is critical for neuronal growth and survival. Chaperone-mediated autophagy dysfunction is closely related to central nervous system diseases. It has been shown that neuronal damage and cell death are accompanied by chaperone-mediated autophagy dysfunction. Under certain conditions, regulation of chaperone-mediated autophagy activity attenuates neurotoxicity. In this paper, we review the changes in chaperone-mediated autophagy in neurodegenerative diseases, brain injury, glioma, and autoimmune diseases. We also summarize the most recent research progress on chaperone-mediated autophagy regulation and discuss the potential of chaperone-mediated autophagy as a therapeutic target for central nervous system diseases.

The dual role of striatal interneurons: circuit modulation and trophic support for the basal ganglia

ABSTRACT

Striatal interneurons play a key role in modulating striatal-dependent behaviors, including motor activity and reward and emotional processing. Interneurons not only provide modulation to the basal ganglia circuitry under homeostasis but are also involved in changes to plasticity and adaptation during disease conditions such as Parkinson's or Huntington's disease. This review aims to summarize recent findings regarding the role of striatal cholinergic and GABAergic interneurons in providing circuit modulation to the basal ganglia in both homeostatic and disease conditions. In addition to direct circuit modulation, striatal interneurons have also been shown to provide trophic support to maintain neuron populations in adulthood. We discuss this interesting and novel role of striatal interneurons, with a focus on the maintenance of adult dopaminergic neurons from interneuron-derived sonic-hedgehog.

Molecular mechanisms underlying microglial sensing and phagocytosis in synaptic pruning

ABSTRACT

Microglia are the main non-neuronal cells in the central nervous system that have important roles in brain development and functional connectivity of neural circuits. In brain physiology, highly dynamic microglial processes are facilitated to sense the surrounding environment and stimuli. Once the brain switches its functional states, microglia are recruited to specific sites to exert their immune functions, including the release of cytokines and phagocytosis of cellular debris. The crosstalk of microglia between neurons, neural stem cells, endothelial cells, oligodendrocytes, and astrocytes contributes to their functions in synapse pruning, neurogenesis, vascularization, myelination, and blood-brain barrier permeability. In this review, we highlight the neuron-derived "find-me," "eat-me," and "don't eat-me" molecular signals that drive microglia in response to changes in neuronal activity for synapse refinement during brain development. This review reveals the molecular mechanism of neuron-microglia interaction in synaptic pruning and presents novel ideas for the synaptic pruning of microglia in disease, thereby providing important clues for discovery of target drugs and development of nervous system disease treatment methods targeting synaptic dysfunction.

Long non-coding RNAs with essential roles in neurodegenerative disorders

ABSTRACT

Recently, with the advent of high-resolution and high-throughput sequencing technologies, an increasing number of long non-coding RNAs (lncRNAs) have been found to be involved in the regulation of neuronal function in the central nervous system with specific spatiotemporal patterns, across different neurodegenerative diseases. However, the underlying mechanisms of lncRNAs during neurodegeneration remain poorly understood. This review provides an overview of the current knowledge of the biology of lncRNAs and focuses on introducing the latest identified roles, regulatory mechanisms, and research status of lncRNAs in Alzheimer's disease, Parkinson's disease, Huntington's disease, and amyotrophic lateral sclerosis. Finally, this review discusses the potential values of lncRNAs as diagnostic biomarkers and therapeutic targets for neurodegenerative diseases, hoping to provide broader implications for developing effective treatments.

Microglial response to aging and neuroinflammation in the development of neurodegenerative diseases

ABSTRACT

Cellular senescence and chronic inflammation in response to aging are considered to be indicators of brain aging; they have a great impact on the aging process and are the main risk factors for neurodegeneration. Reviewing the microglial response to aging and neuroinflammation in neurodegenerative diseases will help understand the importance of microglia in neurodegenerative diseases. This review describes the origin and function of microglia and focuses on the role of different states of the microglial response to aging and chronic inflammation on the occurrence and development of neurodegenerative diseases, including Alzheimer's disease, Huntington's chorea, and Parkinson's disease. This review also describes the potential benefits of treating neurodegenerative diseases by modulating changes in microglial states. Therefore, inducing a shift from the neurotoxic to neuroprotective microglial state in neurodegenerative diseases induced by aging and chronic inflammation holds promise for the treatment of neurodegenerative diseases in the future.

Amyloid-beta and tau protein beyond Alzheimer's disease

ABSTRACT

The aggregation of amyloid-beta peptide and tau protein dysregulation are implicated to play key roles in Alzheimer's disease pathogenesis and are considered the main pathological hallmarks of this devastating disease. Physiologically, these two proteins are produced and expressed within the normal human body. However, under pathological conditions, abnormal expression, post-translational modifications, conformational changes, and truncation can make these proteins prone to aggregation, triggering specific disease-related cascades. Recent studies have indicated associations between aberrant behavior of amyloid-beta and tau proteins and various neurological diseases, such as Alzheimer's disease, Parkinson's disease, and amyotrophic lateral sclerosis, as well as retinal neurodegenerative diseases like Glaucoma and age-related macular degeneration. Additionally, these proteins have been linked to cardiovascular disease, cancer, traumatic brain injury, and diabetes, which are all leading causes of morbidity and mortality. In this comprehensive review, we provide an overview of the connections between amyloid-beta and tau proteins and a spectrum of disorders.

Intranasal administration of stem cell-derived exosomes for central nervous system diseases

ABSTRACT

Exosomes, lipid bilayer-enclosed small cellular vesicles, are actively secreted by various cells and play crucial roles in intercellular communication. These nanosized vesicles transport internalized proteins, mRNA, miRNA, and other bioactive molecules. Recent findings have provided compelling evidence that exosomes derived from stem cells hold great promise as a therapeutic modality for central nervous system disorders. These exosomes exhibit multifaceted properties including anti-apoptotic, anti-inflammatory, neurogenic, and vasculogenic effects. Furthermore, exosomes offer several advantages over stem cell therapy, such as high preservation capacity, low immunogenicity, the ability to traverse the blood-brain barrier, and the potential for drug encapsulation. Consequently, researchers have turned their attention to exosomes as a novel therapeutic avenue. Nonetheless, akin to the limitations of stem cell treatment, the limited accumulation of exosomes in the injured brain poses a challenge to their clinical application. To overcome this hurdle, intranasal administration has emerged as a non-invasive and efficacious route for delivering drugs to the central nervous system. By exploiting the olfactory and trigeminal nerve axons, this approach enables the direct transport of therapeutics to the brain while bypassing the blood-brain barrier. Notably, exosomes, owing to their small size, can readily access the nerve pathways using this method. As a result, intranasal administration has gained increasing recognition as an optimal therapeutic strategy for exosome-based treatments. In this comprehensive review, we aim to provide an overview of both basic and clinical research studies investigating the intranasal administration of exosomes for the treatment of central nervous system diseases. Furthermore, we elucidate the underlying therapeutic mechanisms and offer insights into the prospect of this approach.

Satellite glial cells in sensory ganglia play a wider role in chronic pain via multiple mechanisms

Satellite glial cells are unique glial cells that surround the cell body of primary sensory neurons. An increasing body of evidence suggests that in the presence of inflammation and nerve damage, a significant number of satellite glial cells become activated, thus triggering a series of functional changes. This suggests that satellite glial cells are closely related to the occurrence of chronic pain. In this review, we first summarize the morphological structure, molecular markers, and physiological functions of satellite glial cells. Then, we clarify the multiple key roles of satellite glial cells in chronic pain, including gap junction hemichannel Cx43, membrane channel Pannexin1, K channel subunit 4.1, ATP, purinergic P2 receptors, and a series of additional factors and their receptors, including tumor necrosis factor, glutamate, endothelin, and bradykinin. Finally, we propose that future research should focus on the specific sorting of satellite glial cells, and identify genomic differences between physiological and pathological conditions. This review provides an important perspective for clarifying mechanisms underlying the peripheral regulation of chronic pain and will facilitate the formulation of new treatment plans for chronic pain.

Promising use of metformin in treating neurological disorders: biomarker-guided therapies

Neurological disorders are a diverse group of conditions that affect the nervous system and include neurodegenerative diseases (Alzheimer's disease, multiple sclerosis, Parkinson's disease, Huntington's disease), cerebrovascular conditions (stroke), and neurodevelopmental disorders (autism spectrum disorder). Although they affect millions of individuals around the world, only a limited number of effective treatment options are available today. Since most neurological disorders express mitochondria-related metabolic perturbations, metformin, a biguanide type II antidiabetic drug, has attracted a lot of attention to be repurposed to treat neurological disorders by correcting their perturbed energy metabolism. However, controversial research emerges regarding the beneficial/detrimental effects of metformin on these neurological disorders. Given that most neurological disorders have complex etiology in their pathophysiology and are influenced by various risk factors such as aging, lifestyle, genetics, and environment, it is important to identify perturbed molecular functions that can be targeted by metformin in these neurological disorders. These molecules can then be used as biomarkers to stratify subpopulations of patients who show distinct molecular/pathological properties and can respond to metformin treatment, ultimately developing targeted therapy. In this review, we will discuss mitochondria-related metabolic perturbations and impaired molecular pathways in these neurological disorders and how these can be used as biomarkers to guide metformin-responsive treatment for the targeted therapy to treat neurological disorders.

Antisense therapy: a potential breakthrough in the treatment of neurodegenerative diseases

Neurodegenerative diseases are a group of disorders characterized by the progressive degeneration of neurons in the central or peripheral nervous system. Currently, there is no cure for neurodegenerative diseases and this means a heavy burden for patients and the health system worldwide. Therefore, it is necessary to find new therapeutic approaches, and antisense therapies offer this possibility, having the great advantage of not modifying cellular genome and potentially being safer. Many preclinical and clinical studies aim to test the safety and effectiveness of antisense therapies in the treatment of neurodegenerative diseases. The objective of this review is to summarize the recent advances in the development of these new technologies to treat the most common neurodegenerative diseases, with a focus on those antisense therapies that have already received the approval of the U.S. Food and Drug Administration.

Tumor necrosis factor-stimulated gene-6 ameliorates early brain injury after subarachnoid hemorrhage by suppressing NLRC4 inflammasome-mediated astrocyte pyroptosis

Subarachnoid hemorrhage is associated with high morbidity and mortality and lacks effective treatment. Pyroptosis is a crucial mechanism underlying early brain injury after subarachnoid hemorrhage. Previous studies have confirmed that tumor necrosis factor-stimulated gene-6 (TSG-6) can exert a neuroprotective effect by suppressing oxidative stress and apoptosis. However, no study to date has explored whether TSG-6 can alleviate pyroptosis in early brain injury after subarachnoid hemorrhage. In this study, a C57BL/6J mouse model of subarachnoid hemorrhage was established using the endovascular perforation method. Our results indicated that TSG-6 expression was predominantly detected in astrocytes, along with NLRC4 and gasdermin-D (GSDMD). The expression of NLRC4, GSDMD and its N-terminal domain (GSDMD-N), and cleaved caspase-1 was significantly enhanced after subarachnoid hemorrhage and accompanied by brain edema and neurological impairment. To explore how TSG-6 affects pyroptosis during early brain injury after subarachnoid hemorrhage, recombinant human TSG-6 or a siRNA targeting TSG-6 was injected into the cerebral ventricles. Exogenous TSG-6 administration downregulated the expression of NLRC4 and pyroptosis-associated proteins and alleviated brain edema and neurological deficits. Moreover, TSG-6 knockdown further increased the expression of NLRC4, which was accompanied by more severe astrocyte pyroptosis. In summary, our study revealed that TSG-6 provides neuroprotection against early brain injury after subarachnoid hemorrhage by suppressing NLRC4 inflammasome activation-induced astrocyte pyroptosis.

P7C3-A20 treats traumatic brain injury in rats by inhibiting excessive autophagy and apoptosis

Traumatic brain injury is a severe health problem leading to autophagy and apoptosis in the brain. 3,6-Dibromo-beta-fluoro-N-(3-methoxyphenyl)-9H-carbazole-9-propanamine (P7C3-A20) can be neuroprotective in various diseases, including ischemic stroke and neurodegenerative diseases. However, whether P7C3-A20 has a therapeutic effect on traumatic brain injury and its possible molecular mechanisms are unclear. Therefore, in the present study, we investigated the therapeutic effects of P7C3-A20 on traumatic brain injury and explored the putative underlying molecular mechanisms. We established a traumatic brain injury rat model using a modified weight drop method. P7C3-A20 or vehicle was injected intraperitoneally after traumatic brain injury. Severe neurological deficits were found in rats after traumatic brain injury, with deterioration in balance, walking function, and learning memory. Furthermore, hematoxylin and eosin staining showed significant neuronal cell damage, while terminal deoxynucleotidyl transferase mediated dUTP nick end labeling staining indicated a high rate of apoptosis. The presence of autolysosomes was observed using transmission electron microscope. P7C3-A20 treatment reversed these pathological features. Western blotting showed that P7C3-A20 treatment reduced microtubule-associated protein 1 light chain 3-II (LC3-II) autophagy protein, apoptosis-related proteins (namely, Bcl-2/adenovirus E1B 19-kDa-interacting protein 3 [BNIP3], and Bcl-2 associated x protein [Bax]), and elevated ubiquitin-binding protein p62 (p62) autophagy protein expression. Thus, P7C3-A20 can treat traumatic brain injury in rats by inhibiting excessive autophagy and apoptosis.

Cost dynamics of onshore wind energy in the context of China's carbon neutrality target

Wind energy has become one of the most important measures for China to achieve its carbon neutrality goal. The spatial and temporal evolvement of economic competitiveness for wind energy becomes an important concern in shaping the decarbonization pathway in China. There has been an urgent need in power system planning to model the future dynamics of cost decline and supply potential for wind power in the context of carbon neutrality until 2060. Existing studies often fail to capture the rapid decline in the cost of wind power generation in recent years, and the prediction of wind power cost decline is more conservative than the reality. This study constructs an integrated model to evaluate the cost-competitiveness and grid parity potential of China's onshore wind electricity at fine spatial resolution with updated parameters. Results indicate that the total onshore wind potential amounts to 54.0 PWh. The average levelized cost of wind power is expected to decline from CNY 0.39 kWh-1 in 2020 to CNY 0.30 and CNY 0.21 kWh-1 in 2030 and 2060. 28.3%, 67.6%, and 97.6% of the technical potentials hold power costs lower than coal power in 2020, 2030, and 2060.

New insights into the therapeutic approaches for the treatment of tauopathies

Tauopathies are a group of neurological disorders, including Alzheimer's disease and frontotemporal dementia, which involve progressive neurodegeneration, cognitive deficits, and aberrant tau protein accumulation. The development of tauopathies cannot currently be stopped or slowed down by treatment measures. Given the significant contribution of tau burden in primary tauopathies and the strong association between pathogenic tau accumulation and cognitive deficits, there has been a lot of interest in creating therapies that can alleviate tau pathology and render neuroprotective effects. Recently, small molecules, immunotherapies, and gene therapy have been used to reduce the pathological tau burden and prevent neurodegeneration in animal models of tauopathies. However, the major pitfall of the current therapeutic approach is the difficulty of drugs and gene-targeting modalities to cross the blood-brain barrier and their unintended side effects. In this review, the current therapeutic strategies used for tauopathies including the use of oligonucleotide-based gene therapy approaches that have shown a promising result for the treatment of tauopathies and Alzheimer's disease in preclinical animal models, have been discussed.

The autophagy protein Atg9 functions in glia and contributes to parkinsonian symptoms in a Drosophila model of Parkinson's disease

Parkinson's disease is a progressive neurodegenerative disease characterized by motor deficits, dopaminergic neuron loss, and brain accumulation of α-synuclein aggregates called Lewy bodies. Dysfunction in protein degradation pathways, such as autophagy, has been demonstrated in neurons as a critical mechanism for eliminating protein aggregates in Parkinson's disease. However, it is less well understood how protein aggregates are eliminated in glia, the other cell type in the brain. In the present study, we show that autophagy-related gene 9 (Atg9), the only transmembrane protein in the autophagy machinery, is highly expressed in Drosophila glia from adult brain. Results from immunostaining and live cell imaging analysis reveal that a portion of Atg9 localizes to the trans-Golgi network, autophagosomes, and lysosomes in glia. Atg9 is persistently in contact with these organelles. Lacking glial atg9 reduces the number of omegasomes and autophagosomes, and impairs autophagic substrate degradation. This suggests that glial Atg9 participates in the early steps of autophagy, and hence the control of autophagic degradation. Importantly, loss of glial atg9 induces parkinsonian symptoms in Drosophila including progressive loss of dopaminergic neurons, locomotion deficits, and glial activation. Our findings identify a functional role of Atg9 in glial autophagy and establish a potential link between glial autophagy and Parkinson's disease. These results may provide new insights on the underlying mechanism of Parkinson's disease.

Astrocytic calcium waves: unveiling their roles in sleep and arousal modulation

Neuron-astrocyte interactions are vital for the brain's connectome. Understanding astrocyte activities is crucial for comprehending the complex neural network, particularly the population-level functions of neurons in different cortical states and associated behaviors in mammals. Studies on animal sleep and wakefulness have revealed distinct cortical synchrony patterns between neurons. Astrocytes, outnumbering neurons by nearly fivefold, support and regulate neuronal and synaptic function. Recent research on astrocyte activation during cortical state transitions has emphasized the influence of norepinephrine as a neurotransmitter and calcium waves as key components of ion channel signaling. This summary focuses on a few recent studies investigating astrocyte-neuron interactions in mouse models during sleep, wakefulness, and arousal levels, exploring the involvement of noradrenaline signaling, ion channels, and glutamatergic signaling in different cortical states. These findings highlight the significant impact of astrocytes on large-scale neuronal networks, influencing brain activity and responsiveness. Targeting astrocytic signaling pathways shows promise for treating sleep disorders and arousal dysregulation. More research is needed to understand astrocytic calcium signaling in different brain regions and its implications for dysregulated brain states, requiring future human studies to comprehensively investigate neuron-astrocyte interactions and pave the way for therapeutic interventions in sleep- and arousal-related disorders.

The 2022 report of synergetic roadmap on carbon neutrality and clean air for China: Accelerating transition in key sectors

China is now confronting the intertwined challenges of air pollution and climate change. Given the high synergies between air pollution abatement and climate change mitigation, the Chinese government is actively promoting synergetic control of these two issues. The Synergetic Roadmap project was launched in 2021 to track and analyze the progress of synergetic control in China by developing and monitoring key indicators. The Synergetic Roadmap 2022 report is the first annual update, featuring 20 indicators across five aspects: synergetic governance system and practices, progress in structural transition, air pollution and associated weather-climate interactions, sources, sinks, and mitigation pathway of atmospheric composition, and health impacts and benefits of coordinated control. Compared to the comprehensive review presented in the 2021 report, the Synergetic Roadmap 2022 report places particular emphasis on progress in 2021 with highlights on actions in key sectors and the relevant milestones. These milestones include the proportion of non-fossil power generation capacity surpassing coal-fired capacity for the first time, a decline in the production of crude steel and cement after years of growth, and the surging penetration of electric vehicles. Additionally, in 2022, China issued the first national policy that synergizes abatements of pollution and carbon emissions, marking a new era for China's pollution-carbon co-control. These changes highlight China's efforts to reshape its energy, economic, and transportation structures to meet the demand for synergetic control and sustainable development. Consequently, the country has witnessed a slowdown in carbon emission growth, improved air quality, and increased health benefits in recent years.