Netrin-1 Ameliorates Postoperative Delirium-Like Behavior in Aged Mice by Suppressing Neuroinflammation and Restoring Impaired Blood-Brain Barrier Permeability

Postoperative delirium (POD) is a common and serious postoperative complication in elderly patients, and its underlying mechanism is elusive and without effective therapy at present. In recent years, the neuroinflammatory hypothesis has been developed in the pathogenesis of POD, in which the damaged blood-brain barrier (BBB) plays an important role. Netrin-1 (NTN-1), an axonal guidance molecule, has been reported to have strong inflammatory regulatory and neuroprotective effects. We applied NTN-1 (45 μg/kg) to aged mice using a POD model with a simple laparotomy to assess their systemic inflammation and neuroinflammation by detecting interleukin-6 (IL-6), interleukin-10 (IL-10), and high mobility group box chromosomal protein-1 (HMGB-1) levels. We also assessed the reactive states of microglia and the permeability of the BBB by detecting cell junction proteins and the leakage of dextran. We found that a single dose of NTN-1 prophylaxis decreased the expression of IL-6 and HMGB-1 and upregulated the expression of IL-10 in the peripheral blood, hippocampus, and prefrontal cortex. Nerin-1 reduced the activation of microglial cells in the hippocampus and prefrontal cortex and improved POD-like behavior. NTN-1 also attenuated the anesthesia/surgery-induced increase in BBB permeability by upregulating the expression of tight junction-associated proteins such as ZO-1, claudin-5, and occludin. These findings confirm the anti-inflammatory and BBB protective effects of NTN-1 in an inflammatory environment in vivo and provide better insights into the pathophysiology and potential treatment of POD.

Transcriptional Analysis-Based Alterations Affecting Neuritogenesis of the Peripheral Nervous System in Psoriasis

An increasing amount of evidence indicates the critical role of the cutaneous nervous system in the initiation and maintenance of psoriatic skin lesions by neurogenic inflammation. However, molecular mechanisms affecting cutaneous neurons are largely uncharacterized. Therefore, we reanalyzed a psoriatic RNA sequencing dataset from published transcriptome experiments of nearly 300 individuals. Using the Ingenuity Pathway Analysis software, we associated several hundreds of differentially expressed transcripts (DETs) to nervous system development and functions. Since neuronal projections were previously reported to be affected in psoriasis, we performed an in-depth analysis of neurite formation-related process. Our in silico analysis suggests that SEMA-PLXN and ROBO-DCC-UNC5 regulating axonal growth and repulsion are differentially affected in non-lesional and lesional skin samples. We identified opposing expressional alterations in secreted ligands for axonal guidance signaling (RTN4/NOGOA, NTNs, SEMAs, SLITs) and non-conventional axon guidance regulating ligands, including WNT5A and their receptors, modulating axon formation. These differences in neuritogenesis may explain the abnormal cutaneous nerve filament formation described in psoriatic skin. The processes also influence T-cell activation and infiltration, thus highlighting an additional angle of the crosstalk between the cutaneous nervous system and the immune responses in psoriasis pathogenesis, in addition to the known neurogenic pro-inflammatory mediators.

RNA-Binding Profiles of CKAP4 as an RNA-Binding Protein in Myocardial Tissues

Background: Pathological tissue remodeling such as fibrosis is developed in various cardiac diseases. As one of cardiac activated-myofibroblast protein markers, CKAP4 may be involved in this process and the mechanisms have not been explored.Methods: We assumed that CKAP4 held a role in the regulation of cardiac fibrotic remodeling as an RNA-binding protein. Using improved RNA immunoprecipitation and sequencing (iRIP-seq), we sought to analyze the RNAs bound by CKAP4 in normal atrial muscle (IP1 group) and remodeling fibrotic atrial muscle (IP2 group) from patients with cardiac valvular disease. Quantitative PCR and Western blotting were applied to identify CKAP4 mRNA and protein expression levels in human right atrium samples.Results: iRIP-seq was successfully performed, CKAP4-bound RNAs were characterized. By statistically analyzing the distribution of binding peaks in various regions on the reference human genome, we found that the reads of IP samples were mainly distributed in the intergenic and intron regions implying that CKAP4 is more inclined to combine non-coding RNAs. There were 913 overlapping binding peaks between the IP1 and IP2 groups. The top five binding motifs were obtained by HOMER, in which GGGAU was the binding sequence that appeared simultaneously in both IP groups. Binding peak-related gene cluster enrichment analysis demonstrated these genes were mainly involved in biological processes such as signal transduction, protein phosphorylation, axonal guidance, and cell connection. The signal pathways ranking most varied in the IP2 group compared to the IP1 group were relating to mitotic cell cycle, protein ubiquitination and nerve growth factor receptors. More impressively, peak analysis revealed the lncRNA-binding features of CKAP4 in both IP groups. Furthermore, qPCR verified CKAP4 differentially bound lncRNAs including LINC00504, FLJ22447, RP11-326N17.2, and HELLPAR in remodeling myocardial tissues when compared with normal myocardial tissues. Finally, the expression of CKAP4 is down-regulated in human remodeling fibrotic atrium.Conclusions: We reveal certain RNA-binding features of CKAP4 suggesting a relevant role as an unconventional RNA-binding protein in cardiac remodeling process. Deeper structural and functional analysis will be helpful to enrich the regulatory network of cardiac remodeling and to identify potential therapeutic targets.

Nanopolymers: powerful tools in neuroprotection and neuroregeneration

: Disorders of the central and peripheral nervous systems are still major human health issues. Researchers have been seeking ways to boost neuroregeneration and neuroprotection since ancient times in order to overcome the brain's, spinal cord's, and peripheral nerves' limited ability to regenerate spontaneously.In this scenario, nanopolymers have shown great potential in terms of drug delivery systems and scaffolds, diminishing the scale of tissue damage and promoting functional recovery in both acute and chronic injuries. A diversity of natural and synthetic polymers has been exploited due to the unique characteristics of these polymers regarding their mechanical and biological properties. These properties dictate how the biomaterial interact with biological systems and how they are distinct in each polymer. This makes them suitable for numerous applications that range from the controlled release of an anti-inflammatory drug to axonal guidance. The versatility of nanopolymers makes them a rich source for therapeutic approaches in the neuroscience field, especially in neuroprotection and neuroregeneration.

CRMP4-mediated fornix development involves semaphorin-3E signaling pathway

Neurodevelopmental axonal pathfinding plays a central role in correct brain wiring and subsequent cognitive abilities. Within the growth cone, various intracellular effectors transduce axonal guidance signals by remodeling the cytoskeleton. Semaphorin-3E (Sema3E) is a guidance cue implicated in development of the fornix, a neuronal tract connecting the hippocampus to the hypothalamus. Microtubule-Associated Protein 6 (MAP6) has been shown to be involved in the Sema3E growth-promoting signaling pathway. In this study, we identified the Collapsin Response Mediator Protein 4 (CRMP4) as a MAP6 partner and a crucial effector in Sema3E growth-promoting activity. CRMP4-KO mice displayed abnormal fornix development reminiscent of that observed in Sema3E-KO mice. CRMP4 was shown to interact with the Sema3E tripartite receptor complex within Detergent-Resistant Membrane (DRM) domains, and DRM domain integrity was required to transduce Sema3E signaling through the Akt/GSK3 pathway. Finally, we showed that the cytoskeleton-binding domain of CRMP4 is required for Sema3E's growth-promoting activity, suggesting that CRMP4 plays a role at the interface between Sema3E receptors, located in DRM domains, and the cytoskeleton network. As the fornix is affected in many psychiatric diseases, such as schizophrenia, our results provide new insights to better understand the neurodevelopmental components of these diseases.

Transcriptional Analysis-Based Alterations Affecting Neuritogenesis of the Peripheral Nervous System in Psoriasis

An increasing amount of evidence indicates the critical role of the cutaneous nervous system in the initiation and maintenance of psoriatic skin lesions by neurogenic inflammation. However, molecular mechanisms affecting cutaneous neurons are largely uncharacterized. Therefore, we reanalyzed a psoriatic RNA sequencing dataset from published transcriptome experiments of nearly 300 individuals. Using the Ingenuity Pathway Analysis software, we associated several hundreds of differentially expressed transcripts (DETs) to nervous system development and functions. Since neuronal projections were previously reported to be affected in psoriasis, we performed an in-depth analysis of neurite formation-related processed. Our in silico analysis suggests that SEMA-PLXN and ROBO-DCC-UNC5 regulating axonal growth and repulsion are differentially affected in non-lesional and lesional skin samples. We identified opposing expressional alterations in secreted ligands for axonal guidance signaling (RTN4/NOGOA, NTNs, SEMAs, SLITs) and non-conventional axon guidance regulating ligands, including WNT5A and their receptors, modulating axon formation. These differences in neuritogenesis may explain the abnormal cutaneous nerve filament formation described in psoriatic skin. The processes also influence T cell activation and infiltration, thus highlighting an additional angle of the crosstalk between the cutaneous nervous system and the immune responses in psoriasis pathogenesis, in addition to the known neurogenic pro-inflammatory mediators.

Semaphorin signaling restricts neuronal regeneration in C. elegans

Extracellular signaling proteins serve as neuronal growth cone guidance molecules during development and are well positioned to be involved in neuronal regeneration and recovery from injury. Semaphorins and their receptors, the plexins, are a family of conserved proteins involved in development that, in the nervous system, are axonal guidance cues mediating axon pathfinding and synapse formation. The Caenorhabditis elegans genome encodes for three semaphorins and two plexin receptors: the transmembrane semaphorins, SMP-1 and SMP-2, signal through their receptor, PLX-1, while the secreted semaphorin, MAB-20, signals through PLX-2. Here, we determined the neuronal morphology and locomotion behavior of knockout animals missing each of the semaphorins and plexins; we described the expression pattern of all plexins in the nervous system of C. elegans; and we evaluated their effect on the regeneration of motoneuron neurites and the recovery of locomotion behavior following precise laser microsurgery.

EXTH-53. ANTI-ROBO1 CAR T CELLS EFFECTIVELY TARGET MALIGNANT BRAIN CANCER

No standardized treatment exists for patients with recurrent glioblastoma (GBM). Given the aggressive nature of the disease and difficulty in modeling tumor recurrence, minimal efforts have been made to design rational therapies against it. The roundabout guidance receptor 1 (ROBO1) protein is involved in axonal guidance during neurodevelopment and is aberrantly upregulated in glioma where it mediates glioma cell migration. Here, we present that ROBO1 is highly expressed on the surface of malignant and treatment-refractory brain tumor initiating cells (BTICs), prompting the development of an anti-ROBO1 CAR-T cell therapy. Using the binding region of a single-domain antibody targeting ROBO1, we developed second-generation anti-ROBO1 CAR-T cells specific and effective against ROBO1-expressing BTICs. Upon antigen exposure, anti-ROBO1 CAR-T cells upregulated markers of activation and degranulation. Additionally, treatment of orthotopic and patient-derived brain tumor xenograft models with anti-ROBO1 CAR-T cells resulted in reduced tumor burden and prolonged survival, demonstrating the therapy’s therapeutic potential for treating neoplastic brain malignancies.

Another Piece of the Puzzle of Anomalous Connectivity in Joubert's Syndrome

We report on the conventional and diffusion tensor imaging (DTI) findings of a 2-year-old child with clinical presentation of Joubert's Syndrome (JS) and brainstem structural abnormalities as depicted by neuroimaging.Conventional magnetic resonance imaging (MRI) showed a “molar tooth” configuration of the brainstem. A band-like formation coursing in an apparent axial plane anterior to the interpeduncular fossa was noted and appeared to partially cover the interpeduncular fossa.DTI maps and three-dimensional (3D) tractography demonstrated a prominent red-encoded white matter bundle anterior to the midbrain. Probable aberrant course of the bilateral corticospinal tracts (CST) was also depicted. Absence of the decussation of the superior cerebellar peduncles and elongated thickened, horizontal superior cerebellar peduncle (SCP) reflecting the molar tooth sign were also shown.Our report and the review of the published cases suggest that DTI and tractography may be very helpful to differentiate between interpeduncular heterotopias and similarly located white matter bundles corroborating the underlying etiology of axonal guidance disorders in the complex group of ciliopathies including JS. Our case represents an important additional puzzle piece to explore the variability of these ciliopathies.