Autism patient-derived SHANK2BY29X mutation affects the development of ALDH1A1 negative dopamine neuron.

Autism spectrum disorder (ASD) encompasses a range of neurodevelopmental conditions. Different mutations on a single ASD gene contribute to heterogeneity of disease phenotypes, possibly due to functional diversity of generated isoforms. SHANK2, a causative gene in ASD, demonstrates this phenomenon, but there is a scarcity of tools for studying endogenous SHANK2 proteins in an isoform-specific manner. Here, we report a point mutation on SHANK2, which is found in a patient with autism, located on exon of the SHANK2B transcript variant (NM_133266.5), hereby SHANK2BY29X. This mutation results in an early stop codon and an aberrant splicing event that impacts SHANK2 transcript variants distinctly. Induced pluripotent stem cells (iPSCs) carrying this mutation, from the patient or isogenic editing, fail to differentiate into functional dopamine (DA) neurons, which can be rescued by genetic correction. Available SMART-Seq single-cell data from human midbrain reveals the abundance of SHANK2B transcript in the ALDH1A1 negative DA neurons. We then show that SHANK2BY29X mutation primarily affects SHANK2B expression and ALDH1A1 negative DA neurons in vitro during early neuronal developmental stage. Mice knocked in with the identical mutation exhibit autistic-like behavior, decreased occupancy of ALDH1A1 negative DA neurons and decreased dopamine release in ventral tegmental area (VTA). Our study provides novel insights on a SHANK2 mutation derived from autism patient and highlights SHANK2B significance in ALDH1A1 negative DA neuron.

Surgical intervention combined with weight-bearing walking training promotes recovery in patients with chronic spinal cord injury: a randomized controlled study.

JOURNAL/nrgr/04.03/01300535-202412000-00032/figure1/v/2024-04-08T165401Z/r/image-tiff For patients with chronic spinal cord injury, the conventional treatment is rehabilitation and treatment of spinal cord injury complications such as urinary tract infection, pressure sores, osteoporosis, and deep vein thrombosis. Surgery is rarely performed on spinal cord injury in the chronic phase, and few treatments have been proven effective in chronic spinal cord injury patients. Development of effective therapies for chronic spinal cord injury patients is needed. We conducted a randomized controlled clinical trial in patients with chronic complete thoracic spinal cord injury to compare intensive rehabilitation (weight-bearing walking training) alone with surgical intervention plus intensive rehabilitation. This clinical trial was registered at ClinicalTrials.gov (NCT02663310). The goal of surgical intervention was spinal cord detethering, restoration of cerebrospinal fluid flow, and elimination of residual spinal cord compression. We found that surgical intervention plus weight-bearing walking training was associated with a higher incidence of American Spinal Injury Association Impairment Scale improvement, reduced spasticity, and more rapid bowel and bladder functional recovery than weight-bearing walking training alone. Overall, the surgical procedures and intensive rehabilitation were safe. American Spinal Injury Association Impairment Scale improvement was more common in T7-T11 injuries than in T2-T6 injuries. Surgery combined with rehabilitation appears to have a role in treatment of chronic spinal cord injury patients.

Chronic stress hinders sensory axon regeneration via impairing mitochondrial cristae and OXPHOS.

Spinal cord injury (SCI) often leads to physical limitations, persistent pain, and major lifestyle shifts, enhancing the likelihood of prolonged psychological stress and associated disorders such as anxiety and depression. The mechanisms linking stress with regeneration remain elusive, despite understanding the detrimental impact of chronic stress on SCI recovery. In this study, we investigated the effect of chronic stress on primary sensory axon regeneration using a preconditioning lesions mouse model. Our data revealed that chronic stress-induced mitochondrial cristae loss and a decrease in oxidative phosphorylation (OXPHOS) within primary sensory neurons, impeding central axon regrowth. Corticosterone, a stress hormone, emerged as a pivotal player in this process, affecting satellite glial cells by reducing Kir4.1 expression. This led to increased neuronal hyperactivity and reactive oxygen species levels, which, in turn, deformed mitochondrial cristae and impaired OXPHOS, crucial for axonal regeneration. Our study underscores the need to manage psychological stress in patients with SCI for effective sensory-motor rehabilitation.

Huangqin decoction alleviates lipid metabolism disorders and insulin resistance in nonalcoholic fatty liver disease by triggering Sirt1/NF-κB pathway.

BACKGROUND: Nonalcoholic fatty liver disease (NAFLD) is a clinicopathological entity characterized by intrahepatic ectopic steatosis. As a consequence of increased consumption of high-calorie diet and adoption of a sedentary lifestyle, the incidence of NAFLD has surpassed that of viral hepatitis, making it the most common cause of chronic liver disease globally. Huangqin decoction (HQD), a Chinese medicinal formulation that has been used clinically for thousands of years, has beneficial outcomes in patients with liver diseases, including NAFLD. However, the role and mechanism of action of HQD in lipid metabolism disorders and insulin resistance in NAFLD remain poorly understood. AIM: To evaluate the ameliorative effects of HQD in NAFLD, with a focus on lipid metabolism and insulin resistance, and to elucidate the underlying mechanism of action. METHODS: High-fat diet-induced NAFLD rats and palmitic acid (PA)-stimulated HepG2 cells were used to investigate the effects of HQD and identify its potential mechanism of action. Phytochemicals in HQD were analyzed by high-performance liquid chromatography (HPLC) to identify the key components. RESULTS: Ten primary chemical components of HQD were identified by HPLC analysis. In vivo, HQD effectively prevented rats from gaining body and liver weight, improved the liver index, ameliorated hepatic histological aberrations, decreased transaminase and lipid profile disorders, and reduced the levels of pro-inflammatory factors and insulin resistance. In vitro studies revealed that HQD effectively alleviated PA-induced lipid accumulation, inflammation, and insulin resistance in HepG2 cells. In-depth investigation revealed that HQD triggers Sirt1/NF-κB pathway-modulated lipogenesis and inflammation, contributing to its beneficial actions, which was further corroborated by the addition of the Sirt1 antagonist EX-527 that compromised the favorable effects of HQD. CONCLUSION: In summary, our study confirmed that HQD mitigates lipid metabolism disorders and insulin resistance in NAFLD by triggering the Sirt1/NF-κB pathway.

Motor neuron-specific RhoA knockout delays degeneration and promotes regeneration of dendrites in spinal ventral horn after brachial plexus injury.

Dendrites play irreplaceable roles in the nerve conduction pathway and are vulnerable to various insults. Peripheral axotomy of motor neurons results in the retraction of dendritic arbors, and the dendritic arbor can be re-expanded when reinnervation is allowed. RhoA is a target that regulates the cytoskeleton and promotes neuronal survival and axon regeneration. However, the role of RhoA in dendrite degeneration and regeneration is unknown. In this study, we explored the potential role of RhoA in dendrites. A line of motor neuronal RhoA conditional knockout mice was developed by crossbreeding HB9Cre+ mice with RhoAflox/flox mice. We established two models for assaying dendrite degeneration and regeneration, in which the brachial plexus was transection or crush injured, respectively. We found that at 28 days after brachial plexus transection, the density, complexity, and structural integrity of dendrites in the ventral horn of the spinal cord of RhoA conditional knockout mice were slightly decreased compared with that in Cre mice. Dendrites underwent degeneration at 7 and 14 days after brachial plexus transection and recovered at 28-56 days. The density, complexity, and structural integrity of dendrites in the ventral horn of the spinal cord of RhoA conditional knockout mice recovered compared with results in Cre mice. These findings suggest that RhoA knockout in motor neurons attenuates dendrite degeneration and promotes dendrite regeneration after peripheral nerve injury.

Celsr2-mediated morphological polarization and functional phenotype of reactive astrocytes in neural repair.

Neural repair is highly influenced by reactive astrocytes. Atypical cadherin Celsr2 regulates neuron development and axon regeneration, while its role in glial cells remains unexplored. In this study, we show that Celsr2 is highly expressed in spinal astrocytes of adult mice, and knockout of Celsr2 results in reactive astrocytes with longer protrusions preferentially orientated towards lesion borders in culture scratch assay and injured spinal cord, and elevation of total and active Cdc42 and Rac1 protein in western blots. Inactivation of Celsr2 enhances calcium influx in reactive astrocytes in time-lapse imaging. Morphological phenotypes of cultured Celsr2-/- astrocytes are rescued by Cdc42 or Rac1 inhibitors. Following spinal cord injury (SCI), Celsr2-/- mice exhibit smaller lesion cavity and glial scar, enhanced fiber regeneration, weaker microglial response, and improved functional recovery than control animals. Similar phenotypes are found in mice with conditional knockout of Celsr2 in astrocytes. In Celsr2-/- mice, astrocyte phenotype is changed and neuroinflammation is alleviated after injury. Inhibiting Cdc42/Rac1 activities compromises astrocyte polarization and the improvement of neural repair and functional recovery in Celsr2-/- mice with SCI. In conclusion, Celsr2 regulates morphological polarization and functional phenotype of reactive astrocytes and inactivating Celsr2 is a potential therapeutic strategy for neural repair.

γδ T cells recruitment and local proliferation in brain parenchyma benefit anti-neuroinflammation after cerebral microbleeds.

Background: Cerebral microbleeds (CMBs) are an early sign of many neurological disorders and accompanied by local neuroinflammation and brain damage. As important regulators of immune response and neuroinflammation, the biological behavior and role of γδ T cells after CMBs remain largely unknown. Methods: We made a spot injury of microvessel in the somatosensory cortex to mimic the model of CMBs by two-photon laser and in vivo tracked dynamical behaviors of γδ T cells induced by CMBs using TCR-δGFP transgenic mice. Biological features of γδ T cells in the peri-CMBs parenchyma were decoded by flow cytometry and Raman spectra. In wildtype and γδ T cell-deficient mice, neuroinflammation and neurite degeneration in the peri-CMBs cortex were studied by RNAseq, immunostaining and in vivo imaging respectively. Results: After CMBs, γδ T cells in the dural vessels were tracked to cross the meningeal structure and invade the brain parenchyma in a few days, where the division process of γδ T cells were captured. Parenchymal γδ T cells were highly expressed by CXCR6 and CCR6, similar to meningeal γδ T cells, positive for IL-17A and Ki67 (more than 98%), and they contained abundant substances for energy metabolism and nucleic acid synthesis. In γδ T cell-deficient mice, cortical samples showed the upregulation of neuroinflammatory signaling pathways, enhanced glial response and M1 microglial polarization, and earlier neuronal degeneration in the peri-CMBs brain parenchyma compared with wildtype mice. Conclusion: CMBs induce the accumulation and local proliferation of γδ T cells in the brain parenchyma, and γδ T cells exert anti-neuroinflammatory and neuroprotective effects at the early stage of CMBs.

Intranasal delivery of BDNF-loaded small extracellular vesicles for cerebral ischemia therapy.

Mesenchymal stem cells (MSCs) have shown promise for the therapy of cerebral ischemia in animal studies and clinical trials, yet their clinical application still faces many challenges. Utilizing small extracellular vesicles (sEVs) may overcome these challenges. In the study, we overexpressed brain-derived neurotrophic factor (BDNF) in cultured MSCs and purified sEVs using anion exchange chromatography. In an ischemic stroke mouse model, sEVs selectively targeted the peri-infarct region after intranasal administration, and BDNF loading enhanced the efficacy of sEVs in improved functional behavior, neural repair indicated by infarct volume reduction, increased neurogenesis, angiogenesis, synaptic plasticity, and fiber preservation, as well as decreased inflammatory-cytokine expression and glial response. Intranasal administration of sEVs and BDNF-sEVs resulted in upregulation of neuroprotection-related genes and downregulation of inflammation-related genes, and BDNF-sEVs treatment activated the BDNF/TrkB signaling in the ischemic brain. Transcriptomic and proteomic analysis of sEVs and BDNF-sEVs disclosed abundant proteins and miRNAs involved in neuroprotection and anti-inflammation, and BDNF-sEVs showed different characteristics from sEVs. In conclusion, intranasal delivery of sEVs-loaded BDNF is a promising alternative strategy for the therapy of cerebral ischemia.

Corticospinal circuit neuroplasticity may involve silent synapses: Implications for functional recovery facilitated by neuromodulation after spinal cord injury.

Spinal cord injury (SCI) leads to devastating physical consequences, such as severe sensorimotor dysfunction even lifetime disability, by damaging the corticospinal system. The conventional opinion that SCI is intractable due to the poor regeneration of neurons in the adult central nervous system (CNS) needs to be revisited as the CNS is capable of considerable plasticity, which underlie recovery from neural injury. Substantial spontaneous neuroplasticity has been demonstrated in the corticospinal motor circuitry following SCI. Some of these plastic changes appear to be beneficial while others are detrimental toward locomotor function recovery after SCI. The beneficial corticospinal plasticity in the spared corticospinal circuits can be harnessed therapeutically by multiple contemporary neuromodulatory approaches, especially the electrical stimulation-based modalities, in an activity-dependent manner to improve functional outcomes in post-SCI rehabilitation. Silent synapse generation and unsilencing contribute to profound neuroplasticity that is implicated in a variety of neurological disorders, thus they may be involved in the corticospinal motor circuit neuroplasticity following SCI. Exploring the underlying mechanisms of silent synapse-mediated neuroplasticity in the corticospinal motor circuitry that may be exploited by neuromodulation will inform a novel direction for optimizing therapeutic repair strategies and rehabilitative interventions in SCI patients.

Celsr2 Knockout Alleviates Inhibitory Synaptic Stripping and Benefits Motoneuron Survival and Axon Regeneration After Branchial Plexus Avulsion.

Axotomy-induced synaptic stripping modulates survival and axon regeneration of injured motoneurons. Celsr2 is supposed to mediate homophilic interactions of neighboring cells during development, and its role in synaptic stripping remains unknow. In a model of brachial plexus avulsion, Celsr2 knockout improved functional recovery, motoneuron survival, and axon regeneration. Celsr2 was indicated to express in spinal motoneurons, excitatory and inhibitory interneurons, astrocytes, and a subset of oligodendrocytes using Celsr2LacZ mice. Double immunostaining showed that the coverage of inhibitory and excitatory vesicles on injured motoneurons were remarkably reduced after injury, whereas more inhibitory vesicles were maintained in Celsr2-/- mutants than control mice. In the ultrastructure, the density of inhibitory F-boutons on injured motoneurons was higher in Celsr2-/- mutants than controls. Conditional knockout of Celsr2 in astrocytes or oligodendrocytes showed the similar axotomy-induced synaptic withdrawal to the control. RNAseq of injured spinal samples identified 12 MHC I molecules with significant changes between Celsr2-/- and control mice. After injury, expression of MHC I surrounding injured motoneurons was increased, particularly high in Celsr2-/- mutants. In conclusion, Celsr2 knockout enhances MHC I signaling, alleviates inhibitory synaptic stripping cell-autonomously, and contributes to motoneuron survival and regeneration, and Celsr2 is a potential target for neural repair.

A label-free fluorescent biosensor for amplified detection of T4 polynucleotide kinase activity based on rolling circle amplification and catalytic hairpin assembly.

T4 polynucleotide kinase (PNK) plays a key role in maintaining genome integrity and repairing DNA damage. In this paper, we proposed a label-free fluorescent biosensor for amplified detection of T4 PNK activity based on rolling circle amplification (RCA) and catalytic hairpin assembly (CHA). Firstly, we designed a padlock probe with a 5'-hydroxyl terminus for phosphorylation reaction, a complementary sequence of the primer for initiating RCA, and a complementary sequence of the trigger for triggering CHA. T4 PNK catalyzed the phosphorylation reaction by adding a phosphate group to the 5'-hydroxyl terminus of padlock probe, generating a phosphorylated padlock probe. Then it hybridized with the primer to generate a circular probe under the action of ligase. Subsequently, the primer initiated an RCA reaction along the circular probe to synthesize a large molecular weight product with repetitive trigger sequences. The triggers then triggered the cyclic assembly reactions between hairpin probe 1 and hairpin probe 2 to generate a large amount of complexes with free G-rich sequences. The free G-rich sequences folded into G-quadruplex structures, and the N-methylmesoporphyrin IXs were inserted into them to produce an amplified fluorescent signal. Benefiting from high amplification efficiency of RCA and CHA, this fluorescent biosensor could detect T4 PNK as low as 6.63 × 10-4 U mL-1, and was successfully applied to detect its activity in HeLa cell lysates. Moreover, this fluorescent biosensor could effectively distinguish T4 PNK from other alternatives and evaluate the inhibitory effect of inhibitor, indicating that it had great potential in drug screening and disease treatment.

Cervical subtotal discectomy prosthesis validated in non-human primate model: A novel artificial cervical disc replacement concept?

Objective: To evaluate the biological function of cervical subtotal discectomy prosthesis (CSDP) implantation in a non-human primate model. Methods: A CSDP was tested for cytocompatibility and osseointegration capacity before implantation in non-human primates. Subsequently, the CSDP was improved based on three-dimensional CT measurements of the non-human primate cervical spine. Eight cynomolgus monkeys were selected for removal of the intervertebral disc and lower endplate of the C5/6 segment to complete the model construction for CSDP implantation. In 18-month follow-up, physiological indices, radiology, and kinematics were assessed to estimate the biological function of the CSDP in non-human primates, including biosafety, osseointegration, and biomechanics. Results: Co-cultured with the CSDP constituent titanium alloy (Ti6Al4V-AO), the mouse embryo osteoblast precursor cell MC3T3-E1 obtained extended adhesion, remarkable viability status, and cell proliferation. After implantation in the mouse femur for 28 days, the surface of Ti6Al4V-AO was covered by a large amount of new cancellous bone, which formed further connections with the femur cortical bone, and no toxicity was detected by blood physiology indices or histopathology. After completing implantation in primate models, no infection or osteolysis was observed, nor was any subsidence or displacement of the CSDP observed in CT scans in the 18-month follow-up. In particular, the interior of the cervical vertebra fixation structure was gradually filled with new trabecular bone, and the CSDP had achieved fixation and bony fusion in the vertebral body at 1 year post-operation. Meanwhile, no signs of inflammation, spinal cord compression, adjacent segment degeneration, or force line changes were observed in subsequent MRI observations. Moreover, there were no pathological changes of the joint trajectory, joint motion range, stride length, or the stance phase ratio revealed in the kinematics analysis at 3, 6, 12, or 18 months after CSDP implantation. Conclusion: We successfully designed a new cervical subtotal discectomy prosthesis and constructed an excellent non-human primate implantation model for the evaluation of subtotal disc replacement arthroplasty. Furthermore, we demonstrated that CSDP had outstanding safety, osseointegration capacity, and biomechanical stability in a non-human primate model, which might be a new choice in the treatment of cervical disc diseases and potentially change future outcomes of degenerative cervical diseases.

Planar cell polarity protein Celsr2 maintains structural and functional integrity of adult cortical synapses.

A few developmental genes remain persistently expressed in the adult stage, whilst their potential functions in the mature brain remain underappreciated. Here, we report the unexpected importance of Celsr2, a core Planar cell polarity (PCP) component, in maintaining the structural and functional integrity of adult neocortex. Celsr2 is highly expressed during development and remains expressed in adult neocortex. In vivo synaptic imaging in Celsr2 deficient mice revealed alterations in spinogenesis and reduced neuronal calcium activities, which are associated with impaired motor learning. These phenotypes were accompanied with anomalies of both postsynaptic organization and presynaptic vesicles. Knockout of Celsr2 in adult mice recapitulated those features, further supporting the role of Celsr2 in maintaining the integrity of mature cortex. In sum, our data identify previously unrecognized roles of Celsr2 in the maintenance of synaptic function and motor learning in adulthood.

Celsr2 regulates NMDA receptors and dendritic homeostasis in dorsal CA1 to enable social memory.

Social recognition and memory are critical for survival. The hippocampus serves as a central neural substrate underlying the dynamic coding and transmission of social information. Yet the molecular mechanisms regulating social memory integrity in hippocampus remain unelucidated. Here we report unexpected roles of Celsr2, an atypical cadherin, in regulating hippocampal synaptic plasticity and social memory in mice. Celsr2-deficient mice exhibited defective social memory, with rather intact levels of sociability. In vivo fiber photometry recordings disclosed decreased neural activity of dorsal CA1 pyramidal neuron in Celsr2 mutants performing social memory task. Celsr2 deficiency led to selective impairment in NMDAR but not AMPAR-mediated synaptic transmission, and to neuronal hypoactivity in dorsal CA1. Those activity changes were accompanied with exuberant apical dendrites and immaturity of spines of CA1 pyramidal neurons. Strikingly, knockdown of Celsr2 in adult hippocampus recapitulated the behavioral and cellular changes observed in knockout mice. Restoring NMDAR transmission or CA1 neuronal activities rescued social memory deficits. Collectively, these results show a critical role of Celsr2 in orchestrating dorsal hippocampal NMDAR function, dendritic and spine homeostasis, and social memory in adulthood.

Celsr3 Inactivation in the Brainstem Impairs Rubrospinal Tract Development and Mouse Behaviors in Motor Coordination and Mechanic-Induced Response.

Inactivation of Celsr3 in the forebrain results in defects of longitudinal axonal tracts such as the corticospinal tract. In this study, we inactivated Celsr3 in the brainstem using En1-Cre mice (Celsr3 cKO) and analyzed axonal and behavioral phenotypes. Celsr3 cKO animals showed an 83% reduction of rubrospinal axons and 30% decrease of corticospinal axons in spinal segments, associated with increased branching of dopaminergic fibers in the ventral horn. Decreases of spinal motoneurons, neuromuscular junctions, and electromyographic signal amplitude of the biceps were also found in mutant animals. Mutant mice had impaired motor coordination and defective response to heavy mechanical stimulation, but no disability in walking and food pellet handling. Transsynaptic tracing demonstrated that rubrospinal axons synapse on spinal neurons in the deep layer of the dorsal horn, and mechanical stimulation of hindpaws induced strong calcium signal of red nuclei in control mice, which was less prominent in mutant mice. In conclusion, Celsr3 regulates development of spinal descending axons and the motor network in cell and non-cell autonomous manners, and the maturation of the rubrospinal system is required for motor coordination and response to mechanical stimulation.

Entropy analysis and grey cluster analysis of multiple indexes of 5 kinds of genuine medicinal materials.

5 kinds of genuine medicinal materials, including Diding (Latin name: Corydalis bungeana Turcz), Purslane (Latin name: Portulaca oleracea L.), straw sandal board (Latin name: Hoya carnosa (L.f.) R. Br), June snow (Latin name: Serissa japonica (Thunb.) Thunb.), pine vine rattan (Latin name: Lycopodiastrum casuarinoides (Spring) Holub. [Lycopodium casuarinoides Spring]), were selected as the research objects. The combustion heat, thermo gravimetric parameters, and fat content, calcium content, trace element content, ash content of 5 kinds of genuine medicinal materials were measured. The combustion heat, differential thermal gravimetric analysis, fat content, calcium content, trace elements content, and ash content of 5 kinds of genuine medicinal materials were used to build a systematic multi-index evaluation system by gray pattern recognition and grey correlation coefficient cluster analysis, which can make up for the gaps in this area and provide scientific basis and research significance for the study of genuine medicinal materials quality. The results showed that the order of combustion heat of 5 kinds of genuine medicinal materials, including Diding, Purslane, straw sandal board, June snow, pine vine rattan, was Diding > June snow > straw sandal board > Purslane > pine vine rattan, the order of fat content (%) of 5 kinds of genuine medicinal materials was straw sandal board > Diding > pine vine rattan > June snow > Purslane, the order of calcium content (%) was pine vine rattan > June snow > Purslane > straw sandal board > Diding, the order of ash content was June snow > Purslane > straw sandal board > pine vine rattan > Diding. From the analysis of thermogravimetric analysis results and thermogravimetric combustion stability, the order of combustion stability of 5 kinds of genuine medicinal materials was June snow > pine Vine rattan > straw sandal board > Diding > Portulaca oleracea. The order of the content of 12 trace elements in 5 kinds of genuine medicinal materials, in terms of trace element content, June snow contains the highest trace elements in all samples. According to combustion heat, combustibility (combustion stability of genuine medicinal materials), fat, calcium, ash, trace element content, the comprehensive evaluation results of multi-index analysis constructed by gray correlation degree, gray correlation coefficient factor analysis, and gray hierarchical cluster analysis showed that the comprehensive evaluation multi-index order of 5 genuine medicinal materials, including Diding, Purslane, straw sandal board, June snow and pine vine rattan, was June snow > straw sandal board > Diding > Purslane > pine vine rattan. Therefore, the comprehensive evaluation results of the quality of genuine medicinal materials selected in this study were June snow the best, followed by straw sandal board. This research has important theoretical and practical significance for the multi-index measurement and comprehensive evaluation of genuine medicinal materials, and can provide scientific basis and research significance for the research of multi-index quality control of genuine medicinal material.

Inactivating Celsr2 promotes motor axon fasciculation and regeneration in mouse and human.

Understanding new modulators of axon regeneration is central to neural repair. Our previous work demonstrated critical roles of atypical cadherin Celsr2 during neural development, including cilia organization, neuron migration and axon navigation. Here, we address its role in axon regeneration. We show that Celsr2 is highly expressed in both mouse and human spinal motor neurons. Celsr2 knockout promotes axon regeneration and fasciculation in mouse cultured spinal explants. Similarly, cultured Celsr2 mutant motor neurons extend longer neurites and larger growth cones, with increased expression of end-binding protein 3 and higher potassium-induced calcium influx. Mice with Celsr2 conditional knockout in spinal motor neurons do not exhibit any behavioural deficits; however, after branchial plexus injury, axon regeneration and functional forelimb locomotor recovery are significantly improved. Similarly, knockdown of CELSR2 using shRNA interference in cultured human spinal motor explants and motor neurons increases axonal fasciculation and growth. In mouse adult spinal cord after root avulsion, in mouse embryonic spinal cords, and in cultured human motor neurons, Celsr2 downregulation is accompanied by increased levels of GTP-bound Rac1 and Cdc42, and of JNK and c-Jun. In conclusion, Celsr2 negatively regulates motor axon regeneration and is a potential target to improve neural repair.

The Role of Klotho Protein Against Sevoflurane-Induced Neuronal Injury.

The effects of general anesthetics on the developing brain have aroused much attention in recent years. Sevoflurane, a commonly used inhalation anesthetic especially in pediatric anesthesia, can induce developmental neurotoxicity. In this study, the differentially expressed mRNAs in the hippocampus of newborn rats exposed to 3% sevoflurane for 6 h were detected by RNA-Sequencing. Those data indicated that the mRNA of Klotho was increased after exposure to sevoflurane. Moreover, the protein expression of Klotho was assayed by Western Blot. Besides over-expression and under-expression of Klotho protein, we also detected changes of cell proliferation, ROS, JC-1, and Bcl-2/Bax ratio in PC12 cells exposed to sevoflurane. After exposure to 3% sevoflurane, the expression of Klotho protein increased in the hippocampus of neonatal rats. In PC12 cells, exposure to sevoflurane could increase cellular ROS level, reduce mitochondrial membrane potential and Bcl-2/Bax ratio. While overexpression of Klotho alleviated the above changes, knockdown of Klotho aggravated the injury of sevoflurane. Klotho protein could reduce oxidative stress and mitochondrial injury induced by sevoflurane in the neuron.

The Celsr3-Kif2a axis directs neuronal migration in the postnatal brain.

The tangential migration of immature neurons in the postnatal brain involves consecutive migration cycles and depends on constant remodeling of the cell cytoskeleton, particularly in the leading process (LP). Despite the identification of several proteins with permissive and empowering functions, the mechanisms that specify the direction of migration remain largely unknown. Here, we report that planar cell polarity protein Celsr3 orients neuroblasts migration from the subventricular zone (SVZ) to olfactory bulb (OB). In Celsr3-forebrain conditional knockout mice, neuroblasts loose directionality and few can reach the OB. Celsr3-deficient neuroblasts exhibit aberrant branching of LP, de novo LP formation, and decreased growth rate of microtubules (MT). Mechanistically, we show that Celsr3 interacts physically with Kif2a, a MT depolymerizing protein and that conditional inactivation of Kif2a in the forebrain recapitulates the Celsr3 knockout phenotype. Our findings provide evidence that Celsr3 and Kif2a cooperatively specify the directionality of neuroblasts tangential migration in the postnatal brain.

IL-27 signalling promotes adipocyte thermogenesis and energy expenditure.

Thermogenesis in brown and beige adipose tissue has important roles in maintaining body temperature and countering the development of metabolic disorders such as obesity and type 2 diabetes1,2. Although much is known about commitment and activation of brown and beige adipose tissue, its multiple and abundant immunological factors have not been well characterized3-6. Here we define a critical role of IL-27-IL-27Rα signalling in improving thermogenesis, protecting against diet-induced obesity and ameliorating insulin resistance. Mechanistic studies demonstrate that IL-27 directly targets adipocytes, activating p38 MAPK-PGC-1α signalling and stimulating the production of UCP1. Notably, therapeutic administration of IL-27 ameliorated metabolic morbidities in well-established mouse models of obesity. Consistently, individuals with obesity show significantly decreased levels of serum IL-27, which can be restored after bariatric surgery. Collectively, these findings show that IL-27 has an important role in orchestrating metabolic programs, and is a highly promising target for anti-obesity immunotherapy.