Neural Cell Adhesion Molecule L1 Research Articles

The Neuroprotective Effect of Neural Cell Adhesion Molecule L1 in the Hippocampus of Aged Alzheimer's Disease Model Mice.

Alzheimer's disease (AD) is a severe neurodegenerative disorder and the most common form of dementia, causing the loss of cognitive function. Our previous study has shown, using a doubly mutated mouse model of AD (APP/PS1), that the neural adhesion molecule L1 directly binds amyloid peptides and decreases plaque load and gliosis when injected as an adeno-associated virus construct (AAV-L1) into APP/PS1 mice. In this study, we microinjected AAV-L1, using a Hamilton syringe, directly into the 3-month-old APP/PS1 mouse hippocampus and waited for a year until significant neurodegeneration developed. We stereologically counted the principal neurons and parvalbumin-positive interneurons in the hippocampus, estimated the density of inhibitory synapses around principal cells, and compared the AAV-L1 injection models with control injections of green fluorescent protein (AAV-GFP) and the wild-type hippocampus. Our results show that there is a significant loss of granule cells in the dentate gyrus of the APP/PS1 mice, which was improved by AAV-L1 injection, compared with the AAV-GFP controls (p < 0.05). There is also a generalized loss of parvalbumin-positive interneurons in the hippocampus of APP/PS1 mice, which is ameliorated by AAV-L1 injection, compared with the AAV-GFP controls (p < 0.05). Additionally, AAV-L1 injection promotes the survival of inhibitory synapses around the principal cells compared with AAV-GFP controls in all three hippocampal subfields (p < 0.01). Our results indicate that L1 promotes neuronal survival and protects the synapses in an AD mouse model, which could have therapeutic implications.

Interaction of L1CAM with LC3 Is Required for L1-Dependent Neurite Outgrowth and Neuronal Survival.

The neural cell adhesion molecule L1 (also called L1CAM or CD171) functions not only in cell migration, but also in cell survival, differentiation, myelination, neurite outgrowth, and signaling during nervous system development and in adults. The proteolytic cleavage of L1 in its extracellular domain generates soluble fragments which are shed into the extracellular space and transmembrane fragments that are internalized into the cell and transported to various organelles to regulate cellular functions. To identify novel intracellular interaction partners of L1, we searched for protein-protein interaction motifs and found two potential microtubule-associated protein 1 light-chain 3 (LC3)-interacting region (LIR) motifs within L1, one in its extracellular domain and one in its intracellular domain. By ELISA, immunoprecipitation, and proximity ligation assay using L1 mutant mice lacking the 70 kDa L1 fragment (L1-70), we showed that L1-70 interacts with LC3 via the extracellular LIR motif in the fourth fibronectin type III domain, but not by the motif in the intracellular domain. The disruption of the L1-LC3 interaction reduces L1-mediated neurite outgrowth and neuronal survival.

Mice Mutated in the Third Fibronectin Domain of L1 Show Enhanced Hippocampal Neuronal Cell Death, Astrogliosis and Alterations in Behavior.

Adhesion molecules play major roles in cell proliferation, migration, survival, neurite outgrowth and synapse formation during nervous system development and in adulthood. The neural cell adhesion molecule L1 contributes to these functions during development and in synapse formation and synaptic plasticity after trauma in adulthood. Mutations of L1 in humans result in L1 syndrome, which is associated with mild-to-severe brain malformations and mental disabilities. Furthermore, mutations in the extracellular domain were shown to cause a severe phenotype more often than mutations in the intracellular domain. To explore the outcome of a mutation in the extracellular domain, we generated mice with disruption of the dibasic sequences RK and KR that localize to position 858RKHSKR863 in the third fibronectin type III domain of murine L1. These mice exhibit alterations in exploratory behavior and enhanced marble burying activity. Mutant mice display higher numbers of caspase 3-positive neurons, a reduced number of principle neurons in the hippocampus, and an enhanced number of glial cells. Experiments suggest that disruption of the dibasic sequence in L1 results in subtle impairments in brain structure and functions leading to obsessive-like behavior in males and reduced anxiety in females.

Expression of L1 Cell Adhesion Molecule (L1CAM) in extracellular vesicles in the human spinal cord during development.

L1 cell adhesion molecule (L1CAM) is a glycoprotein characterized by three components: an extracellular region, a transmembrane segment, and a cytoplasmic tail. L1CAM is expressed in multiple human cells, including neurons. The neural cell adhesion molecule L1 has been implicated in a variety of neurologic processes, including neuritogenesis and cerebellar cell migration. The presence of L1CAM on the surface of nerve cells allows the adhesion of neurons among them. Furthermore, when it is bound to itself or to other proteins, L1-CAM induces signals inside the cell. The aim of this work was to study L1CAM expression in the human spinal cord during development, at different gestational ages, through immunohistochemistry. Immunohistochemical analysis for L1CAM was performed in five human spinal cord samples, including three embryos and two fetuses of different gestational ages, ranging from 8 to 12 weeks. L1CAM expression was detected in all 5 spinal cords examined in this study. The adhesion molecule was found in the vast majority of cells. The highest levels of immunoreactivity for L1CAM were detected at the periphery of the developing organs, in the spinal cord zones occupied by sensory and motor fibers. In the alar and basal columns, immunoreactivity for L1CAM was characterized by a reticular pattern, being mainly expressed in axons. Strong reactivity of L1CAM was also found in extracellular vesicles. This extracellular localization might indicate the ability of L1CAM to mediate the transduction of extracellular signals that support axon outgrowth. The high reactivity of L1cam in the axons of developing neurons in the fetal spinal cord confirms previous studies on the ability of L1CAM to promote axon sprouting and branching in the developing nervous system. In this work, a new actor is reported to have a role in the complex field of human spinal cord development: L1CAM, whose expression is highly found in the developing neuronal and glial precursors.

Canonical insulin signaling is not significantly impaired in early stages of depression.

Patients with major depression (MD) are at high-risk for insulin resistance (IR), type-2 diabetes, metabolic syndrome, cardiovascular morbidity and mortality. However, our recent study published in this journal [Eur Arch Psychiatry Clin Neurosci. 2019 Jun;269(4):373-377], found no evidence of IR in acutely-ill drug-naive first-episode MD (FEMD) using the homeostatic model assessment of insulin resistance (HOMA-IR). We concluded, that MD may be related to impaired glucose/insulin homeostasis in the long-term but not in early disease stages. Now, we performed a complementary analysis of the canonical insulin signalling pathway containing the set of control and FEMD samples from the study mentioned above. The first node (pS312-IRS-1, pY-IRS-1) and downstream pathway which affects glucose and lipid homeostasis (phosphorylated proteins: pS473-AKT, pS9-GSK3β, pS2448-mTOR, pT389-p70S6K; total proteins AKT, GSK3β, mTOR, p70S6K) were analyzed by electrochemiluminescence (ECL) in neuronalextracellular vesicles (nEVs) enriched for L1 neural cell adhesion molecule (L1CAM) expression. No significant diagnosis-related differences were observed for the pS312-IRS-1 / pYIRS-1 ratio (P = 0.093), but the mean ratio was reduced by ~ 70% in FEMD versus controls. Moreover, omnibus analysis of downstream phosphorylated / total signaling protein ratios and respective post-hoc analyses revealed no significant changes in FEMD patients versus controls (P = 0.734). HAMD-21 scores were not correlated with pS312-IRS-1 / pY-IRS-1 or downstream phosphorylated/total signaling protein ratios. In summary, we did not find evidence for altered neuronal insulin signaling in early disease stages of MD. This is in contrast to schizophrenia, where we and otherresearchers have seen evidence of IR in first-episode patients.

Mitochondrial and Neuronal Dysfunctions in L1 Mutant Mice.

Adhesion molecules regulate cell proliferation, migration, survival, neuritogenesis, synapse formation and synaptic plasticity during the nervous system’s development and in the adult. Among such molecules, the neural cell adhesion molecule L1 contributes to these functions during development, and in synapse formation, synaptic plasticity and regeneration after trauma. Proteolytic cleavage of L1 by different proteases is essential for these functions. A proteolytic fragment of 70 kDa (abbreviated L1-70) comprising part of the extracellular domain and the transmembrane and intracellular domains was shown to interact with mitochondrial proteins and is suggested to be involved in mitochondrial functions. To further determine the role of L1-70 in mitochondria, we generated two lines of gene-edited mice expressing full-length L1, but no or only low levels of L1-70. We showed that in the absence of L1-70, mitochondria in cultured cerebellar neurons move more retrogradely and exhibit reduced mitochondrial membrane potential, impaired Complex I activity and lower ATP levels compared to wild-type littermates. Neither neuronal migration, neuronal survival nor neuritogenesis in these mutants were stimulated with a function-triggering L1 antibody or with small agonistic L1 mimetics. These results suggest that L1-70 is important for mitochondrial homeostasis and that its absence contributes to the L1 syndrome phenotypes.

Artemisinin upregulates neural cell adhesion molecule L1 to attenuate neurological deficits after intracerebral hemorrhage in mice.

Background and purposeIntracerebral hemorrhage (ICH) is a subtype of stroke and results in neurological deficits in patients without any effective treatments. Artemisinin (ART), a well‐known antimalarial Chinese medicine, exerts multiple essential roles in the central and peripheral nervous system due to its antioxidative and anti‐inflammation properties. Neural cell adhesion molecule L1 (L1CAM, L1) is considered to be implicated in neural development, functional maintenance, and neuroprotection during disease. However, whether these two essential molecules are neuroprotective in ICH remains unclear.MethodsTherefore, the present study investigated the influence of ART on the recovery of neurological deficits in a mouse model of ICH induced by collagenase and the underlying mechanism.ResultsIt was revealed that ART is capable of upregulating L1 expression to alleviate brain edema, reduce oxidative stress, and inhibit inflammation to alleviate ICH‐induced brain injury to improve the neurological outcome in mice suffering from ICH.ConclusionThese results may lay the foundation for ART to be a novel candidate treatment for ICH.

Galectins and Their Ligand Glycoconjugates in the Central Nervous System Under Physiological and Pathological Conditions.

Galectins are β-galactoside-binding lectins consisting of 15 members in mammals. Galectin-1,-3,-4,-8, and -9 are predominantly expressed in the central nervous system (CNS) and regulate various physiological and pathological events. This review summarizes the current knowledge of the cellular expression and role of galectins in the CNS, and discusses their functions in neurite outgrowth, myelination, and neural stem/progenitor cell niches, as well as in ischemic/hypoxic/traumatic injuries and neurodegenerative diseases such as multiple sclerosis. Galectins are expressed in both neurons and glial cells. Galectin-1 is mainly expressed in motoneurons, whereas galectin-3-positive neurons are broadly distributed throughout the brain, especially in the hypothalamus, indicating its function in the regulation of homeostasis, stress response, and the endocrine/autonomic system. Astrocytes predominantly contain galectin-1, and galectin-3 and−9 are upregulated along with its activation. Activated, but not resting, microglia contain galectin-3, supporting its phagocytic activity. Galectin-1,−3, and -4 are characteristically expressed during oligodendrocyte differentiation. Galectin-3 from microglia promotes oligodendrocyte differentiation and myelination, while galectin-1 and axonal galectin-4 suppress its differentiation and myelination. Galectin-1- and- 3-positive cells are involved in neural stem cell niche formation in the subventricular zone and hippocampal dentate gyrus, and the migration of newly generated neurons and glial cells to the olfactory bulb or damaged lesions. In neurodegenerative diseases, galectin-1,-8, and -9 have neuroprotective and anti-inflammatory activities. Galectin-3 facilitates pro-inflammatory action; however, it also plays an important role during the recovery period. Several ligand glycoconjugates have been identified so far such as laminin, integrins, neural cell adhesion molecule L1, sulfatide, neuropilin-1/plexinA4 receptor complex, triggering receptor on myeloid cells 2, and T cell immunoglobulin and mucin domain. N-glycan branching on lymphocytes and oligodendroglial progenitors mediated by β1,6-N-acetylglucosaminyltransferase V (Mgat5/GnTV) influences galectin-binding, modulating inflammatory responses and remyelination in neurodegenerative diseases. De-sulfated galactosaminoglycans such as keratan sulfate are potential ligands for galectins, especially galectin-3, regulating neural regeneration. Galectins have multitudinous functions depending on cell type and context as well as post-translational modifications, including oxidization, phosphorylation, S-nitrosylation, and cleavage, but there should be certain rules in the expression patterns of galectins and their ligand glycoconjugates, possibly related to glucose metabolism in cells.

Small compounds mimicking the adhesion molecule L1 improve recovery in a zebrafish demyelination model

Demyelination leads to a loss of neurons, which results in, among other consequences, a severe reduction in locomotor function, and underlies several diseases in humans including multiple sclerosis and polyneuropathies. Considerable clinical progress has been made in counteracting demyelination. However, there remains a need for novel methods that reduce demyelination while concomitantly achieving remyelination, thus complementing the currently available tools to ameliorate demyelinating diseases. In this study, we used an established zebrafish demyelination model to test selected compounds, following a screening in cell culture experiments and in a mouse model of spinal cord injury that was aimed at identifying beneficial functions of the neural cell adhesion molecule L1. In comparison to mammalian nervous system disease models, the zebrafish allows testing of potentially promotive compounds more easily than what is possible in mammals. We found that our selected compounds tacrine and duloxetine significantly improved remyelination in the peripheral and central nervous system of transgenic zebrafish following pharmacologically induced demyelination. Given that both molecules are known to positively affect functions other than those related to L1 and in other disease contexts, we propose that their combined beneficial function raises hope for the use of these compounds in clinical settings.

Tacrine alleviates neuropathic pain in mice by mimicking the cell adhesion molecule L1

Neuropathic pain, which is caused by nervous system damage or dysfunctions, remains one of the most intractable challenges in modern medicine due to the lack of effective drugs. Tacrine, which is a small organic compound, is known to mimic the beneficial characteristics of the neural cell adhesion molecule L1 (L1CAM, L1) in vitro. Although previous studies indicated that L1 constitutes a viable strategy for promoting regeneration after nervous system injury, it is not clear whether L1 has a definite role in peripheral nerve injury. In this study, we observed that tacrine eased thermal hyperalgesia and mechanical allodynia after sciatic nerve chronic construction injury and restored functional morphological damage. Furthermore, tacrine suppressed the proliferation and activation of glia and reduced the level of IL-1β, IL-6 and TNF-α. Tacrine also inhibited the JAK2/STAT3 signaling pathway, which is involved in neuroinflammation. These observations indicated that tacrine is a promising candidate for an analgesic agent for neuropathic pain.

Abstract 2858: Comparative surface proteomic analysis of human breast cancer cell lines

Abstract Enrichment of cell surface proteins is commonly performed by biotinylation using amine-based chemistry; however, this method is often associated with intracellular labeling and difficulty distinguishing the true cell surface proteins from background contaminants. We developed a robust cell surface protein isolation method using amine-based chemistry that is compatible with mass spectrometry (MS). We applied this methodology to evaluate the surface proteomes of three breast cancer cell lines, including hormone responsive MCF-7 cells, and two triple negative breast cancer cell lines (TNBC), BT549 and Hs5789T. Thermo Scientific™ Tandem Mass Tag (TMT) Reagents, combined with high pH reverse phase fractionation of the labeled peptides, were used to multiplex protein identification and quantitative analyses by tandem MS. A heat map of enriched proteins from the three cell lines showed clearly distinct banding patterns of clustered protein groups. Relative quantitative differences in several classes of enriched proteins were observed, including tyrosine kinases, G-Protein-Coupled Receptors (GPCRs), and cell adhesion proteins. The tyrosine kinase EGFR was found to be more highly expressed in TNBC cell lines compared with MCF-7 cells. In contrast, the receptor tyrosine-protein kinase erbB-3 was found to be significantly higher in the MCF-7 cells compared with the TNBC cells. Several GPCRs were identified and found to vary across the three cell lines, including Frizzled 7 which is an emerging target for cancer therapy. Multiple cell adhesion proteins were also identified, including neural cell adhesion molecule L1 which promotes migration of MCF7 cells. Where possible, the data set was found to be consistent with literature reports. In conclusion, we have developed a highly sensitive method for cell surface proteomic analyses that can be effectively used to identify differences in cell types as well as for biomarker discovery and potential drug therapy targets. Citation Format: Betsy Benton, Sergei Snovida, Katherine Herting, Kay Opperman, Barbara Kaboord. Comparative surface proteomic analysis of human breast cancer cell lines [abstract]. In: Proceedings of the Annual Meeting of the American Association for Cancer Research 2020; 2020 Apr 27-28 and Jun 22-24. Philadelphia (PA): AACR; Cancer Res 2020;80(16 Suppl):Abstract nr 2858.

Berberine enhances L1 expression and axonal remyelination in rats after brachial plexus root avulsion.

Background and PurposeEnhanced remyelination of the regenerated axons results in functional re‐innervation and improved functional motor recovery after brachial plexus root avulsion (BPRA). The neural cell adhesion molecule L1 (L1CAM, L1) regulates myelination and promotes regeneration after acute injury in the nervous system. Berberine (BBR) can exert neuroprotective roles against the lesion. Herein, we investigated whether berberine (BBR) can affect the expression of L1 and enhance the axonal remyelination in rats following BPRA.MethodsThe surgical procedures were performed to build the rat brachial plexus avulsion and re‐implantation model, and then, the rats were treated with BBR. After the rehabilitation for 12 weeks, the musculocutaneous nerves were collected for quantitative real‐time PCR, Western blot analysis, and histochemical and immunofluorescence staining.ResultsWe observed that, BBR treatment ameliorated the abnormal musculocutaneous nerve fibers morphology, up‐regulated the L1 expression, increased the myelination‐related genes, decreased the differentiated‐associated genes, and up‐regulated the phosphorylation of ERK.ConclusionThese results suggest that BBR may enhance L1 expression and promote axonal remyelination after spinal root avulsion.

Downregulation of Adhesion Molecule CHL1 in B Cells but Not T Cells of Patients with Major Depression and in the Brain of Mice with Chronic Stress.

Depression is a common serious mental disorder with unclear pathogenesis. Currently, specific diagnostic biomarkers are yet to be characterized. The close homolog of L1 (CHL1) is a L1 family cell adhesion molecule involved in the regulation of neuronal survival and growth. Although genome-wide expression profiling of human lymphoblastoid cell lines (LCLs) reported neural cell adhesion molecule (NCAM) L1 as a tentative biomarker for selective serotonin reuptake inhibitor (SSRI) antidepressant response, the involvement of CHL1 in depression is unclear. In this study, using a well-established chronic unpredictable mild stress (CUMS) depression mouse model, we examined the mRNA and protein expression of CHL1 in normal control, CUMS, vehicle (VEH), fluoxetine (FLU), and clozapine (CLO) groups. We found that in the CUMS group, both mRNA and protein expression of CHL1 were downregulated in both the hippocampus and the cortex. Treatment of CUMS mice with FLU and CLO reversed CHL1 mRNA and protein expression. In the human study, we showed that CHL1 expression was significantly downregulated in monocytes of unipolar and bipolar depressive patients compared with healthy donors (HD) at both mRNA and protein levels. Consistently, ELISA showed that CHL1 levels in the serum of patients with depression were reduced and negatively correlated with their HRSD-21 scores. Further flow cytometry studies showed that the reduced number of CHL1 positive CD19+ and CD20+ B cells of patients with depression was subsequently reversed with antidepressant treatment. Our findings suggested that downregulation of CHL1 from both immune cells and the brain may be linked to the immunopathogenesis of depression. In conclusion, CHL1 may be an important predictive marker for both diagnosis and treatment outcome of depression.

A mimetic peptide of α2,6-sialyllactose promotes neuritogenesis.

Oxidative stress contributes to the pathogenesis of neurodegenerative diseases. With the aim to find reagents that reduce oxidative stress, a phage display library was screened for peptides mimicking α2,6-sialyllactose (6'-SL), which is known to beneficially influence neural functions. Using Sambucus nigra lectin, which specifically binds to 6'-SL, we screened a phage display library and found a peptide comprising identical sequences of 12 amino acids. Mimetic peptide, reverse peptide and scrambled peptide were tested for inhibition of 6'-SL binding to the lectin. Indeed, lectin binding to 6'-SL was inhibited by the most frequently identified mimetic peptide, but not by the reverse or scrambled peptides, showing that this peptide mimics 6'-SL. Functionally, mimetic peptide, but not the reverse or scrambled peptides, increased viability and expression of neural cell adhesion molecule L1 in SK-N-SH human neuroblastoma cells, and promoted survival and neurite outgrowth of cultured mouse cerebellar granule neurons challenged by H2O2-induced oxidative stress. The combined results indicate that the 6'-SL mimetic peptide promotes neuronal survival and neuritogenesis, thus raising hopes for the treatment of neurodegenerative diseases. This study was approved by the Medical Ethics Committee of Shantou University Medical College, China (approval No. SUMC 2014-004) on February 20, 2014.

Neuroprotective Peptide NAPVSIPQ Antagonizes Ethanol Inhibition of L1 Adhesion by Promoting the Dissociation of L1 and Ankyrin-G

BackgroundEthanol causes developmental neurotoxicity partly by blocking adhesion mediated by the L1 neural cell adhesion molecule. This action of ethanol is antagonized by femtomolar concentrations of the neuropeptide NAPVSIPQ (NAP), an active fragment of the activity-dependent neuroprotective protein (ADNP). How femtomolar concentrations of NAP antagonize millimolar concentrations of ethanol is unknown. L1 sensitivity to ethanol requires L1 association with ankyrin-G; therefore, we asked whether NAP promotes the dissociation of ankyrin-G and L1. MethodsL1–ankyrin-G association was studied using immunoprecipitation, Western blotting, and immunofluorescence in NIH/3T3 cells transfected with wild-type and mutated human L1 genes. Phosphorylation of the ankyrin binding motif in the L1 cytoplasmic domain was studied after NAP treatment of intact cells, rat brain homogenates, and purified protein fragments. ResultsFemtomolar concentrations of NAP stimulated the phosphorylation of tyrosine-1229 (L1-Y1229) at the ankyrin binding motif of the L1 cytoplasmic domain, leading to the dissociation of L1 from ankyrin-G and the spectrin-actin cytoskeleton. NAP increased the association of L1 and EphB2 and directly activated EphB2 phosphorylation of L1-Y1229. These actions of NAP were reproduced by P7A-NAP, a NAP variant that also blocks the teratogenic actions of ethanol, but not by I6A-NAP, which does not block ethanol teratogenesis as potently. Finally, knockdown of EPHB2 prevented ethanol inhibition of L1 adhesion in NIH/3T3 cells. ConclusionsNAP potently antagonizes ethanol inhibition of L1 adhesion by stimulating EphB2 phosphorylation of L1-Y1229. EphB2 plays a critical role in synaptic development; its potent activation by NAP suggests that ADNP may mediate synaptic development partly by activating EphB2.

Oligonucleotide Microarrays Identified Potential Regulatory Genes Related to Early Outward Arterial Remodeling Induced by Tissue Plasminogen Activator.

Constrictive vascular remodeling limiting blood flow, as well as compensatory outward remodeling, has been observed in many cardiovascular diseases; however, the underlying mechanisms regulating the remodeling response of the vessels remain unclear. Plasminogen activators (PA) are involved in many of the processes of vascular remodeling. We have shown previously that increased levels of tissue-type PA (tPA) contributes to outward vascular remodeling. To elucidate the mechanisms involved in the induction of outward remodeling we characterized changes in the expression profiles of 8799 genes in injured rat carotid arteries 1 and 4 days after recombinant tPA treatment compared to vehicle. Periadventitial tPA significantly increased lumen size and vessel area, encompassed by the external elastic lamina, at both one and 4 days after treatment. Among 41 differentially expressed known genes 1 day after tPA application, five genes were involved in gene transcription, five genes were related to the regulation of vascular tone [for example, thromboxane A2 receptor (D32080) or non-selective-type endothelin receptor (S65355)], and eight genes were identified as participating in vascular innervation [for example, calpain (D14478) or neural cell adhesion molecule L1 (X59149)]. Four days after injury in tPA-treated arteries, four genes, regulating vascular tone, were differentially expressed. Thus, tPA promotes outward arterial remodeling after injury, at least in part, by regulating expression of genes in the vessel wall related to function of the nervous system and vascular tone.

Phenelzine, a small organic compound mimicking the functions of cell adhesion molecule L1, promotes functional recovery after mouse spinal cord injury.

Neural cell adhesion molecule L1 contributes to nervous system development and maintenance by promoting neuronal survival, neuritogenesis, axonal regrowth/sprouting, myelination, and synapse formation and plasticity. L1 also enhances recovery after spinal cord injury and ameliorates neurodegenerative processes in experimental rodent models. Aiming for clinical translation of L1 into therapy we screened for and functionally characterized in vitro the small organic molecule phenelzine, which mimics characteristic L1 functions. The present study was designed to evaluate the potential of this compound in vivo in a mouse model of spinal cord injury. In mice, intraperitoneal injection of phenelzine immediately after severe thoracic compression, and thereafter once daily for 6 weeks, improved hind limb function, reduced astrogliosis and promoted axonal regrowth/sprouting at 4 and 5 weeks after spinal cord injury compared to vehicle control-treated mice. Phenelzine application upregulated L1 expression in the spinal cord and stimulated the cognate L1-mediated intracellular signaling cascades in the spinal cord tissue. Phenelzine-treated mice showed decreased levels of pro-inflammatory cytokines, such as interleukin-1β, interleukin-6, and tumor necrosis factor-α in the injured spinal cord during the acute phase of inflammation. This study provides new insights into the role of phenelzine in L1-mediated neural functions and modulation of inflammation. The combined results raise hopes that phenelzine may develop into a therapeutic agent for nervous system injuries.

Overexpression of miR-21-5p promotes proliferation and invasion of colon adenocarcinoma cells through targeting CHL1

BackgroundThis study aims to investigate the effect of miR-21-5p on process of colon adenocarcinoma (COAD) cells and its connection with neural cell adhesion molecule L1 (CHL1).MethodsDifferent expressions of mRNAs and miRNAs were calculated with microarray analysis. QRT-PCR and western blot were performed to quantify miR-21-5p and CHL1 expression. Flow Cytometry, MTT assay, colony formation assay, transwell assay and ELISA were performed to evaluate propagation and invasiveness of COAD cells. Dual luciferase reporter assay was employed to scrutinize the relationship between miR-21-5P and CHL1. We performed in vivo experiment to detect the impact of miR-21-5p and CHL1 on COAD tumor growth.ResultsExpression level of miR-21-5p increased in both COAD tissues and cells. MTT and Cell cycle assay showed that overexpression of miR-21-5p accelerated proliferation of COAD cells. Transwell assay indicated that miR-21-5p promoted cell invasion. The result of dual luciferase reporter assay indicated that miR-21-5p targeted CHL1 directly and inhibited its expression. The result of in vivo experiments showed that down-regulation of miR-21-5p decreased the volume and weight of tumor, while knockdown of CHLI stimulated tumor growth.ConclusionsThe overexpression of miR-21-5p can promote propagation and invasiveness of COAD cells through inhibiting the expression of CHL1.

The human CSF pain proteome

Chronic pain represents one of the major medical challenges in the 21st century, affecting >1.5 billion of the world population. Overlapping and heterogenous symptoms of various chronic pain conditions complicate their diagnosis, emphasizing the need for more specific biomarkers to improve the diagnosis and understand the disease mechanisms.We have here investigated proteins found in human CSF with respect to known “pain” genes and in a cohort of patients with dysfunctional pain (fibromyalgia, FM), inflammatory pain (rheumatoid arthritis patients, RA) and non-pain controls utilized semi-quantitative proteomics using mass spectrometry (MS) to explore quantitative differences between these cohorts of patients.We found that “pain proteins” detected in CSF using MS are typically related to synaptic transmission, inflammatory responses, neuropeptide signaling- and hormonal activity. In addition, we found ten proteins potentially associated with chronic pain in FM and RA: neural cell adhesion molecule L1, complement C4-A, lysozyme C, receptor-type tyrosine-protein phosphatase zeta, apolipoprotein D, alpha-1-antichymotrypsin, granulins, calcium/calmodulin-dependent protein kinase type II subunit alpha, mast/stem cell growth factor receptor Kit, prolow-density lipoprotein receptor-related protein 1. These proteins might be of importance for understanding the mechanisms of dysfunctional/inflammatory chronic pain and also for use as potential biomarkers. SignificanceChronic pain is a common disease and it poses a large burden on worldwide health. Fibromyalgia (FM) is a heterogeneous disease of unknown etiology characterized by chronic widespread pain (CWP). The diagnosis and treatment of FM is based on the analysis of clinical assessments and no measurable biomarkers are available. Cerebrospinal fluid (CSF) has been historically considered as a rich source of biomarkers for diseases of nervous system including chronic pain. Here, we explore CSF proteome of FM patients utilizing mass spectrometry based quantitative proteomics method combined with multivariate data analysis in order to monitor the dynamics of the CSF proteome. Our findings in this exploratory study support notable presence of pain related proteins in CSF yet with specific domains including inflammatory responses, neuropeptide signaling- and hormonal activity. We have investigated molecular functions of significantly altered proteins and demonstrate presence of 176 known pain related proteins in CSF. In addition, we found ten proteins potentially associated with pain in FM and RA: neural cell adhesion molecule L1, complement C4-A, lysozyme C, receptor-type tyrosine-protein phosphatase zeta, apolipoprotein D, alpha-1-antichymotrypsin, granulins, calcium/calmodulin-dependent protein kinase type II subunit alpha, mast/stem cell growth factor receptor Kit, prolow-density lipoprotein receptor-related protein 1. These proteins are novel in the context of FM but are known to be involved in pain mechanisms including inflammatory response and signal transduction. These results should be of clear significance and interest for researchers and clinicians working in the field of pain utilizing human CSF and MS based proteomics.

Axonal Guidance Signaling Pathway Is Suppressed in Human Nasal Polyps.

Background Dysfunctional innervation might contribute to the pathogenesis of chronic rhinosinusitis with nasal polyps (CRSwNP), but the state of the axonal outgrowth signaling in CRSwNP is unknown. The purpose of this study was to explore the axonal outgrowth pathway-related protein expression in CRSwNP. Methods Institutional review board approved study in which tissue proteomes were compared between control and CRSwNP patients (n = 10/group) using an aptamer-based proteomic array and confirmed by whole transcriptomic analysis. Results Compared with controls, proteins associated with axonal guidance signaling pathway such as beta-nerve growth factor, semaphorin 3A, Ras-related C3 botulinum toxin substrate 1, Bcl-2, protein kinase C delta type, and Fyn were significantly decreased in patients with CRSwNP (fold change [FC] = -1.17, P = .002; FC = -1.09, P < .001; FC = -1.33, P < .001; FC = -1.31, P < .001; FC = -1.31, P = .004; and FC = -1.20, P = 0.012, respectively). In contrast, reticulon-4 receptor, an inhibitory factor, was significantly increased in patients with CRSwNP (FC = 1.25, P < .001). Furthermore, neuronal growth-associated proteins such as ciliary neurotrophic factor receptor subunit alpha, neuronal growth regulator 1, neuronal cell adhesion molecule, neural cell adhesion molecule L1, platelet-derived growth factor subunit A, and netrin-4 were all significantly decreased in patients with CRSwNP (FC = -1.25, P < .001; FC = -1.27, P = .002; FC = -1.65, P = .013; FC = -4.20, P < .001; FC = -1.28, P < .001; and FC = -2.31, P < .001, respectively). In contrast, tissue eosinophil count ( P < .001) and allergic inflammation factors such as IgE, periostin, and galectin-10 were all significantly increased in patients with CRSwNP (FC = 12.28, P < .001; FC = 3.95, P < .001; and FC = 2.44, P < .001, respectively). Furthermore, the log FC of the studied proteins expression significantly and positively correlated with log FC of their mRNA expression ( P < .001, r = .88). Conclusions Axonal guidance signaling and neural growth factors pathways proteins are significantly suppressed in eosinophilic CRSwNP.