Collapsin Response Mediator Protein Research Articles

Bone marrow stromal cells promote neuroplasticity of cerebral ischemic rats via a phosphorylated CRMP2-mediated mechanism

Collapsin response mediator protein 2 (CRMP2), an important protein involved in axonal growth and the maintenance of neuronal membrane integrity, has proved to be altered in nervous system diseases. This study was aimed to investigate the role of CRMP2 in bone marrow stromal cells (BMSCs) treating rats with cerebral ischemia. BMSCs were isolated from shaft of the femurs, tibiae, and humeri and were intra-carotid administrated immediately after middle cerebral artery occlusion (MCAO). Modified Neurological Severity Scores (mNSS) was conducted at 3, 7, 14dpo and the electrophysiologic evaluation was evaluated at 14dpo. Then all rats were sacrificed and brain tissues were harvested for RT-PCR, Western blot and Immunohistochemistry analysis. We found BMSCs treatment significantly improved the neurobehavioral performance impaired by ischemic brain injury, accompanied with the notably increasing levels of Synaptophysin (SYP) and Growth associated protein 43 (GAP43). We also found the protein level of phosphorylated CRMP2 (p-CRMP2) and phosphorylation-mediated protein including Glycogen synthase kinase 3 Beta (GSK3β), Cyclin-dependent kinase 5 (CDK5) were dramatically downregulated in ischemic rats following BMSCs transplant. Furthermore, the GSK3β-mediated factors including neurotrophic and signaling factors were all significantly upregulated in BMSCs-treated group. On the basis of these findings, we suggest that the neuroplasticity effect of BMSCs on cerebral ischemia may be associated with the phosphorylated modulation of CRMP2.

Changes of collapsin response mediator protein-2 and its phosphorylated protein levels following optic nerve injury

Background Collapsin response mediator protein-2 (CRMP-2) can promote the growth of axons, but CRMP-2 occurs hyperphosphorylation under the induction of cyclin-dependent kinase-5 (CDK5) after central nervous system injury, which leads to the collapse of the growth cone and hinders the repair of nervous system.Being a central nervous system tissue, whether the expressions of CRMP-2 and its phosphorylated protein (p-CRMP-2) change after optic nerve injury are rarely studied. Objective This study was to investigate the dynamic changes of CRMP-2 and p-CRMP-2 expressions in injured optic nerve tissue. Methods Forty-eight 8-or 9-week-old BALB/c mice were randomly divided into the sham operation group and postoperative 3-, 7-and 14-day group.Optic nerves were exposed and clamped at retrobulbar 2 mm for 10 seconds in the right eyes during the surgery in the postoperative 3-, 7-and 14-day groups, and the same operation was performed except the clamp of optic nerve in the sham operation group.The optic nerve tissue was obtained from the eyes 3, 7 and 14 days after surgery.The relative expression levels of CRMP-2 mRNA and CRMP-2, p-CRMP-2 and CDK5 proteins in the tissue were detected by real-time fluorescence quantitative PCR and Western blot, respectively.The use and care of the experimental animals complied with the Regulation for the Administration of Affair Concerning Experimental Animals of Third Military Medical University. Results No significant differences were found in the expression levels of CRMP-2 mRNA and CRMP-2 protein among the sham operation group and postoperative 3-, 7-and 14-day groups (CRMP-2 mRNA: F=2.971, P=0.097; CRMP-2 protein: F=1.202, P=0.370). The relative expression levels of p-CRMP-2 protein in the optical nerve were 0.001±0.000, 0.064±0.003, 0.136±0.005 and 0.346±0.012, and those of CDK5 protein were 0.440±0.009, 0.723±0.011, 0.874±0.015 and 0.952±0.019 in the sham operation group and postoperative 3-, 7-and 14-day groups respectively, showing statistically significant differences among them (p-CRMP-2: F=445.600, P<0.001; CDK5: F=186.600, P<0.001), and the relative expression levels of p-CRMP-2 and CDK5 protein were evidently higher in the optical nerve tissue in the postoperative 3-, 7-and 14-day groups than those in the sham operation group (all at P<0.01). Conclusions There are not significant changes in the expression level of CRMP-2 in the BALB/c mice after optic nerve injury.However, the expression levels of p-CRMP-2 and CDK5 proteins are gradually upregulated as the extending of injured time. Key words: Collapsin response mediator protein-2; Cyclin-dependent kinase-5; Central nervous system; Injury, optic nerve; Growth cones; Protein phosphorylation; Mice, BALB/c

MiR-200a-3p promotes the proliferation of human esophageal cancer cells by post-transcriptionally regulating cytoplasmic collapsin response mediator protein-1.

The dysregulation of cytoplasmic collapsin response mediator protein1 (CRMP1) has been reported in lung cancer, medulloblastoma and esophageal cancer. However, the role of CRMP1 and its regulatory mechanisms in esophageal cancer remain unclear. In this study, we demonstrated that CRMP1 expression was downregulated in esophageal cancer tissues and that there were differences in its expression levels in different esophageal cancer cell lines. We found that CRMP1 overexpression inhibited the proliferation of esophageal cancer cells, whereas the silencing of CRMP1 promoted cell proliferation. We performed an analysis of potential microRNA(miRNA or miR) target sites using a commonly used prediction algorithm(TargetScan). The algorithm predicted that miR‑200a-3p targets the 3'untranslated region(3'UTR) of CRMP1. Further experiments confirmed this prediction. In addition, we found that miR‑200a-3p promoted the proliferation of esophageal cancer cells. Thus, our findings indicate that miR‑200a-3p promotes the proliferation of human esophageal cancer cells by post-transcriptionally regulating CRMP1.

Autoantibody-Associated Central Nervous System Neurologic Disorders

Autoimmune neurology is a rapidly evolving new subspecialty driven by the discovery of novel neural- (neuronal- or glial-) specific autoantibodies and their target antigens. The neurologic manifestations affecting the central nervous system include encephalitis, dementia, epilepsy, and movement and sleep disorders. Laboratory testing is now available for most of these neural-specific autoantibodies, which serve as diagnostic markers, in some instances directing the physician toward specific cancer types (e.g., N-methyl-D-aspartic acid receptor antibodies for teratoma, collapsin response mediator protein 5 for small-cell lung cancer) and assisting in therapeutic decision making. Antibodies targeting intracellular proteins serve as markers of cytotoxic effector T-cell-mediated injury, which is generally poorly responsive to immunotherapy. By contrast, antibodies targeting extracellular plasma membrane proteins may act as pathogenic effectors and often infer good responses to immunotherapy. Diagnosing these conditions and implementing treatment as early into the clinical course as possible ensures the best possible clinical outcomes. An adequate immunotherapy trial to assess maximum reversibility of symptoms, as assessed through objective functional measures, is crucial and can help to determine whether maintenance therapy is needed.

A novel mouse model for the identification of thioredoxin-1 protein interactions

Thiol switches are important regulators of cellular signaling and are coordinated by several redox enzyme systems including thioredoxins, peroxiredoxins, and glutathione. Thioredoxin-1 (Trx1), in particular, is an important signaling molecule not only in response to redox perturbations, but also in cellular growth, regulation of gene expression, and apoptosis. The active site of this enzyme is a highly conserved C-G-P-C motif and the redox mechanism of Trx1 is rapid which presents a challenge in determining specific substrates. Numerous in vitro approaches have identified Trx1-dependent thiol switches; however, these findings may not be physiologically relevant and little is known about Trx1 interactions in vivo. In order to identify Trx1 targets in vivo, we generated a transgenic mouse with inducible expression of a mutant Trx1 transgene to stabilize intermolecular disulfides with protein substrates. Expression of the Trx1 “substrate trap” transgene did not interfere with endogenous thioredoxin or glutathione systems in brain, heart, lung, liver, and kidney. Following immunoprecipitation and proteomic analysis, we identified 41 homeostatic Trx1 interactions in perinatal lung, including previously described Trx1 substrates such as members of the peroxiredoxin family and collapsin response mediator protein 2. Using perinatal hyperoxia as a model of oxidative injury, we found 17 oxygen-induced interactions which included several cytoskeletal proteins which may be important to alveolar development. The data herein validates this novel mouse model for identification of tissue- and cell-specific Trx1-dependent pathways that regulate physiological signals in response to redox perturbations.

Increased phosphorylation of collapsin response mediator protein-2 at Thr514 correlates with β-amyloid burden and synaptic deficits in Lewy body dementias.

Collapsin response mediator protein-2 (CRMP2) regulates axonal growth cone extension, and increased CRMP2 phosphorylation may lead to axonal degeneration. Axonal and synaptic pathology is an important feature of Lewy body dementias (LBD), but the state of CRMP2 phosphorylation (pCRMP2) as well as its correlations with markers of neurodegeneration have not been studied in these dementias. Hence, we measured CRMP2 phosphorylation at Thr509, Thr514 and Ser522, as well as markers of β-amyloid (Aβ), tau-phosphorylation, α-synuclein and synaptic function in the postmortem neocortex of a longitudinally assessed cohort of LBD patients characterized by low (Parkinson’s disease dementia, PDD) and high (dementia with Lewy bodies, DLB) burden of Alzheimer type pathology. We found specific increases of pCRMP2 at Thr514 in DLB, but not PDD. The increased CRMP2 phosphorylation correlated with fibrillogenic Aβ as well as with losses of markers for axon regeneration (β-III-tubulin) and synaptic integrity (synaptophysin) in LBD. In contrast, pCRMP2 alterations did not correlate with tau-phosphorylation or α-synuclein, and also appear unrelated to immunoreactivities of putative upstream kinases glycogen synthase kinase 3β and cyclin-dependent kinase 5, as well as to protein phosphatase 2A. In conclusion, increased pCRMP2 may underlie the axonal pathology of DLB, and may be a novel therapeutic target. However, antecedent signaling events as well as the nature of pCRMP2 association with Aβ and other neuropathologic markers require further study.Electronic supplementary materialThe online version of this article (doi:10.1186/s13041-016-0264-9) contains supplementary material, which is available to authorized users.

Comprehensive behavioral study and proteomic analyses of CRMP2-deficient mice.

Collapsin response mediator protein 2 (CRMP2) plays a key role in axon guidance, dendritic morphogenesis and cell polarization. CRMP2 is implicated in various neurological and psychiatric disorders. However, invivo functions of CRMP2 remain unknown. We generated CRMP2 gene-deficient (crmp2-/- ) mice and examined their behavioral phenotypes. During 24-h home cage monitoring, the activity level during the dark phase of crmp2-/- mice was significantly higher than that of wild-type (WT) mice. Moreover, the time during the open arm of an elevated plus maze was longer for crmp2-/- mice than for WT mice. The duration of social interaction was shorter for crmp2-/- mice than for WT mice. Crmp2-/- mice also showed mild impaired contextual learning. We then examined the methamphetamine-induced behavioral change of crmp2-/- mice. Crmp2-/- mice showed increased methamphetamine-induced ambulatory activity and serotonin release. Crmp2-/- mice also showed altered expression of proteins involved in GABAergic synapse, glutamatergic synapse and neurotrophin signaling pathways. In addition, SNAP25, RAB18, FABP5, ARF5 and LDHA, which are related genes to schizophrenia and methamphetamine sensitization, are also decreased in crmp2-/- mice. Our study implies that dysregulation of CRMP2 may be involved in pathophysiology of neuropsychiatric disorders.

Targeting CRMP-4 by lentivirus-mediated RNA interference inhibits SW480 cell proliferation and colorectal cancer growth.

The aim of the present study was to investigate the expression level of collapsin response mediator protein 4 (CRMP-4) in human colorectal cancer (CRC) tissue and to evauluate its impact on SW480 cell proliferation, in addition to tumor growth in a mouse xenograft model. Clinical CRC tissue samples were collected to detect the CRMP-4 protein expression levels using western blot and immunohistochemistry analyses. A specific small interfering RNA sequence targeting the CRMP-4 gene (DPYSL3) was constructed and transfected into an SW480 cell line using a lentivirus vector to obtain a stable cell line with low expression of CRMP-4. The effectiveness of the interference was evaluated using western blot and reverse transcription-quantitative polymerase chain reaction, and the cell proliferation was determined using MTT and BrdU colorimetric methods. Tumor growth was assessed by subcutaneously inoculating the constructed cells into BALB/c nude mice. The protein expression levels of CRMP-4 were markedly increased in colon tumor tissue of the human samples. The proliferation of SW480 cells and the tumor growth rate in nude mice of the si-CPMR-4 group were evidently depressed compared with the si-scramble group. Thus, the present results suggest that CRMP-4 may be involved in the pathogenesis of CRC.

CRMP1 and CRMP2 have synergistic but distinct roles in dendritic development.

Collapsin response mediator protein 2, CRMP2, has been identified as an intracellular signaling mediator for Semaphorin 3A (Sema3A). CRMP2 plays a key role in axon guidance, dendritic morphogenesis, and cell polarization. It has been also implicated in a variety of neurological and psychiatric disorders. However, the invivo functions of CRMP2 remain unknown. We generated CRMP2 gene-deficient (crmp2(-/-) ) mice. The crmp2(-/-) mice showed irregular development of dendritic spines in cortical neurons. The density of dendritic spines was reduced in the cortical layer V pyramidal neurons of crmp2(-/-) mice as well as in those of sema3A(-/-) and crmp1(-/-) mice. However, no abnormality was found in dendritic patterning in crmp2(-/-) compared to wild-type (WT) neurons. The level of CRMP1 was increased in crmp2(-/-) , but the level of CRMP2 was not altered in crmp1(-/-) compared to WT cortical brain lysates. Dendritic spine density and branching were reduced in double-heterozygous sema3A(+/-) ;crmp2(+/-) and sema3A(+/-) ;crmp1(+/-) mice. The phenotypic defects had no genetic interaction between crmp1 and crmp2. These findings suggest that both CRMP1 and CRMP2 mediate Sema3A signaling to regulate dendritic spine maturation and patterning, but through overlapping and distinct signaling pathways.

Collapsin response mediator protein 4 isoforms (CRMP4a and CRMP4b) have opposite effects on cell proliferation, migration, and invasion in gastric cancer.

BackgroundCollapsin response mediator proteins (CRMPs) were originally identified in the nervous system and are involved in neuronal development. Similar to CRMP1, CRMP4 has a shorter transcript encoding a short isoform known as CRMP4a, and a longer transcript encoding a long isoform known as CRMP4b. Previous studies have shown that CRMP4a and CRMP4b exhibit opposing functions in neurite outgrowth. In the present study, we aimed to determine whether CRMP4a and CRMP4b have divergent effects in gastric cancer.MethodsWe first analyzed the mRNA and protein expression levels of CRMP4a and CRMP4b in surgical resected specimens, gastric cancer cell lines and normal gastric epithelial cell line GES-1 by quantitative real-time PCR. Open reading frame and CRMP4b shRNA were generated by lentivirus package and stable cells stably expressing CRMP4a open reading frame and CRMP4b shRNA were constructed. Then the roles of CRMP4a and CRMP4b in cell proliferation, cell cycle progression, apoptosis, migration, invasion, and adhesion were determined by cell proliferation assays, flow cytometry analysis, transwell migration and invasion assays, cell Adhesion Assay, and tumorigenicity assays in nude mice, respectively.ResultsCRMP4a expression was lower and CRMP4b expression was higher in tumor tissue samples as compared to paired non-tumor tissue samples. Additionally, CRMP4a expression was lower and CRMP4b expression was higher in gastric cancer cell lines than in the normal gastric epithelial cell line GES-1. CRMP4a overexpression and CRMP4b silencing suppressed cell proliferation in vitro and in vivo. Additionally, CRMP4a overexpression and CRMP4b silencing induced a significant G1-phase arrest and a decrease of the percentage of cells in S-phase. Furthermore, CRMP4a overexpression and CRMP4b silencing inhibited cell migration, invasion, and adhesion. However, neither CRMP4a overexpression nor CRMP4b silencing affected apoptosis.ConclusionThese results indicate that CRMP4a and CRMP4b have opposite effects on cell proliferation, migration, and invasion in gastric cancer.

Efficacy of (S)-Lacosamide in preclinical models of cephalic pain.

Migraine is one of the world's most common neurological disorders. Current acute migraine treatments have suboptimal efficacy, and new therapeutic options are needed. Approaches targeting calcitonin gene related peptide (CGRP) signaling are clinically effective, but small molecule antagonists have not been advanced because of toxicity. In this study, we explored the axonal growth/specification collapsin response mediator protein 2 (CRMP2) as a novel “druggable” target for inhibiting CGRP release and for potential relevance for treatment of migraine pain. Collapsin response mediator protein 2 has been demonstrated to regulate N-type voltage-gated Ca2+ channel activity and Ca2+-dependent CGRP release in sensory neurons. The coexpression of CRMP2 with N-type voltage-gated Ca2+ channel and CGRP in trigeminal ganglia (TGs) sensory neurons suggested the possibility of a novel approach to regulate CGRP release in the trigeminal system. Screening protocols surprisingly revealed that (S)-lacosamide ((S)-LCM), an inactive analog of the clinically approved small molecule antiepileptic drug (R)-lacosamide (Vimpat), inhibited CRMP2 phosphorylation by cyclin-dependent kinase 5 in rat TG slices and decreased depolarization-evoked Ca2+ influx in TG cells in culture. (S)-LCM significantly blocked capsaicin-evoked CGRP release from dural nerve terminals in the rat in ex vivo cranial cup preparation. Additionally, cephalic and extracephalic cutaneous allodynia induced in rats by activation of dural nociceptors with a cocktail of inflammatory mediators, was inhibited by oral administration of (S)-LCM. The confirmation of CRMP2 as an upstream mediator of CGRP release, together with the brain penetrance of this molecule suggests (S)-LCM as a potential therapy for acute migraine.

INCREASED PHOSPHORYLATION OF COLLAPSIN RESPONSE MEDIATOR PROTEIN-2 AT THR514 IS ASSOCIATED WITH ABETA BURDEN AND AXONAL DEFICITS IN DEMENTIA WITH LEWY BODIES

INCREASED PHOSPHORYLATION OF COLLAPSIN RESPONSE MEDIATOR PROTEIN-2 AT THR514 IS ASSOCIATED WITH ABETA BURDEN AND AXONAL DEFICITS IN DEMENTIA WITH LEWY BODIES

CRMPs Function in Neurons and Glial Cells: Potential Therapeutic Targets for Neurodegenerative Diseases and CNS Injury.

Neurodegeneration in the adult mammalian central nervous system (CNS) is fundamentally accelerated by its intrinsic neuronal mechanisms, including its poor regenerative capacity and potent extrinsic inhibitory factors. Thus, the treatment of neurodegenerative diseases faces many obstacles. The degenerative processes, consisting of axonal/dendritic structural disruption, abnormal axonal transport, release of extracellular factors, and inflammation, are often controlled by the cytoskeleton. From this perspective, regulators of the cytoskeleton could potentially be a therapeutic target for neurodegenerative diseases and CNS injury. Collapsin response mediator proteins (CRMPs) are known to regulate the assembly of cytoskeletal proteins in neurons, as well as control axonal growth and neural circuit formation. Recent studies have provided some novel insights into the roles of CRMPs in several inhibitory signaling pathways of neurodegeneration, in addition to its functions in neurological disorders and CNS repair. Here, we summarize the roles of CRMPs in axon regeneration and its emerging functions in non-neuronal cells, especially in inflammatory responses. We also discuss the direct and indirect targeting of CRMPs as a novel therapeutic strategy for neurological diseases.

Collapsin response mediator protein-1 (CRMP1) acts as an invasion and metastasis suppressor of prostate cancer via its suppression of epithelial\u2013mesenchymal transition and remodeling of actin cytoskeleton organization

The cancer cells can acquire migration and invasion capacities during the metastasis process through the developmental regulatory program epithelial–mesenchymal-transition (EMT), and through its reverse process mesenchymal–epithelial transition cancer cells can recolonize at distant metastatic sites. Among the multifaceted effects exerted by this program, reorganization of actin cytoskeleton is the key mechanical drive for the invasive properties gained by cancer cells. Collapsin response mediator protein-1 (CRMP1) is a cytosolic phosphoprotein and originally characterized as the mediator of semaphorin 3A signaling involved in axon differentiation during neural development. Here we report that CRMP1 can act as a suppressor of tumorigenicity and metastasis in prostate cancer cells. We demonstrated that CRMP1 exhibited a decreased expression pattern in high-grade prostate cancer tissues and many prostate cancer cell lines, and its downregulation in cancer cells was attributed to histone deacetylation and direct repression of its gene by the EMT regulator Snail. Functional analyses revealed that CRMP1 suppressed EMT in prostate cancer cells, as its knockdown could trigger EMT and enhance in vitro invasion capacity, whereas its overexpression could inhibit EMT and suppress both in vitro invasion and in vivo metastasis capacities of prostate cancer cells. Moreover, CRMP1 overexpression could significantly confer resistance to EMT induced by Snail or transforming growth factor-β1 in prostatic epithelial cells and prostate cancer cells. Finally, we demonstrated that CRMP1 could associate with actin and WAVE1, an activator of actin nucleation complex Arp2/3, and also its knockdown could stabilize F-actin and trigger the formation of stress fibers in prostate cancer cells. Together, our study shows that CRMP1 acts an EMT and metastasis suppressor in prostate cancer cells via its regulation of actin polymerization and also suggests that targeting the CRMP1-actin signaling in actin organization could be a potential strategy for management of prostate cancer metastasis.

Caerulein-induced pancreatitis augments the expression and phosphorylation of collapsin response mediator protein 4.

Chronic pancreatitis is a significant risk factor for pancreatic cancer. Previously, we demonstrated that the pancreatic cancer cells show enhanced expression of collapsin response mediator protein 4 (CRMP4) that strongly correlates with severe venous invasion, liver metastasis, and poor prognosis. However, involvement of CRMP4 in acute or chronic pancreatitis remains unknown. Acute and chronic pancreatitis mice models were developed by periodic injection of caerulein. The expression levels of CRMP4 and its phosphorylation were examined. Elevated CRMP4 levels were observed in the infiltrated lymphocytes as well as in the pancreas parenchyma of both acute and chronic pancreatitis. The expression pattern of phosphorylated CRMP4 was similar to that of CRMP4. Cdk5 partially co-localized with the phosphorylated CRMP4. Pancreatitis induces CRMP4 expression in the pancreas parenchyma and in the infiltrated lymphocytes. Overlapping expression of CRMP4 and Cdk5 may suggest that the Cdk5 is at least, in part, responsible for the phosphorylation of CRMP4. The results suggest that CRMP4 is involved in the inflammatory response in pancreatitis. Understanding the mechanisms of CRMP4 would help us to develop novel therapeutic strategies against acute or chronic pancreatitis, and pancreatic cancer.

Anti-collapsin response mediator protein 5 encephalitis masquerading as a low-grade brain tumour

A 71-year-old woman presented acutely with seizures; her MRI suggested a low-grade glioma of the right temporal lobe. Over the preceding 18 months, she had developed progressive limb chorea and...

Sustained relief of ongoing experimental neuropathic pain by a CRMP2 peptide aptamer with low abuse potential.

Uncoupling the protein-protein interaction between collapsin response mediator protein 2 (CRMP2) and N-type voltage-gated calcium channel (CaV2.2) with an allosteric CRMP2-derived peptide (CBD3) is antinociceptive in rodent models of inflammatory and neuropathic pain. We investigated the efficacy, duration of action, abuse potential, and neurobehavioral toxicity of an improved mutant CRMP2 peptide. A homopolyarginine (R9)-conjugated CBD3-A6K (R9-CBD3-A6K) peptide inhibited the CaV2.2-CRMP2 interaction in a concentration-dependent fashion and diminished surface expression of CaV2.2 and depolarization-evoked Ca influx in rat dorsal root ganglia neurons. In vitro studies demonstrated suppression of excitability of small-to-medium diameter dorsal root ganglion and inhibition of subtypes of voltage-gated Ca channels. Sprague-Dawley rats with tibial nerve injury had profound and long-lasting tactile allodynia and ongoing pain. Immediate administration of R9-CBD3-A6K produced enhanced dopamine release from the nucleus accumbens shell selectively in injured animals, consistent with relief of ongoing pain. R9-CBD3-A6K, when administered repeatedly into the central nervous system ventricles of naive rats, did not result in a positive conditioned place preference demonstrating a lack of abusive liability. Continuous subcutaneous infusion of R9-CBD3-A6K over a 24- to 72-hour period reversed tactile allodynia and ongoing pain, demonstrating a lack of tolerance over this time course. Importantly, continuous infusion of R9-CBD3-A6K did not affect motor activity, anxiety, depression, or memory and learning. Collectively, these results validate the potential therapeutic significance of targeting the CaV-CRMP2 axis for treatment of neuropathic pain.

Deregulation of miRNA-181c potentially contributes to the pathogenesis of AD by targeting collapsin response mediator protein 2 in mice

Alzheimer's disease (AD) is a progressive neurodegenerative disorder that is usually accompanied by abnormal gene expression. The 20 to 25 nucleotide (nt) tiny regulators, known as micro ribonucleic acids (miRNAs), have been found to play important roles in the etiology and pathogenesis of various biological processes. The purpose of the current study was to identify the aberrant expression of microRNAs in the hippocampus of an AD mouse model and to investigate its potential role during the progression of AD. The results from microarray analysis showed that several miRNAs were deregulated in the hippocampus tissue of SAMP8 mice compared to SAMR1 mice. Among the deregulated miRNAs, a significant decrease in miR-181c was validated by quantitative real-time PCR. Bioinformatic analysis revealed that miR-181c might be involved in the regulation of axon guidance, MAPK signaling, dorso-ventral axis formation and long-term depression. Moreover, the results of a luciferase activity assay, western blot analysis and immunofluorescent staining showed that over-expression of miR-181c targets the 3′-untranslated region (3′-UTR) of collapsin response mediator protein 2 (crmp2) through its binding sites and down-regulates crmp2 protein abundance at the post-transcriptional level. Taken together, these findings suggested that crmp2 is a target of miR-181c and that the abnormally low expression of miR-181c in the hippocampus of SAMP8 mice could lead to an increase of the crmp2 protein level in AD mice, which might potentially play a role in the pathogenesis of Alzheimer's disease.

Long form collapsin response mediator protein-1 promotes the migration and invasion of osteosarcoma cells.

It has been reported that long form collapsin response mediator protein-1 (LCRMP-1) promotes the metastasis of non-small cell lung cancer. Osteosarcoma (OS) is a human cancer with a high potential for metastasis. The present study aimed to investigate the role of LCRMP-1 in OS metastasis. The expression of LCRMP-1 in OS specimens and cell lines was evaluated using reverse transcription-quantitative polymerase chain reaction (RT-qPCR) and western blot analysis. Furthermore, the migration and invasion of OS cells with LCRMP-1-knockdown was investigated to examine the role of LCRMP-1 in OS metastasis. In addition, the expression of N-cadherin and matrix metalloproteinases (MMPs), which are involved in cell migration, was evaluated using RT-qPCR. Increased expression of LCRMP-1 was observed in the OS tissues and cell lines, accompanied by the enhanced migration and invasion of the OS cells. LCRMP-1-knockdown resulted in a significant decrease in the expression of N-cadherin and MMPs, as well as inhibition of the migration and invasion of the OS cells. Overexpression of LCRMP-1 promoted OS metastasis. Therefore, LCRMP-1 may be a promising target for the effective treatment of OS.

Loss of collapsin response mediator protein 4 suppresses dopaminergic neuron death in an 1-methyl-4-phenyl-1,2,3,6-tetrahydropyridine-induced mouse model of Parkinson's disease.

Parkinson's disease (PD) is a progressive neurodegenerative disorder that is characterized by the selective loss of dopaminergic neurons in the substantia nigra pars compacta (SNc). Several lines of evidence suggest that neurodegeneration in PD is accelerated by a vicious cycle in which apoptosis in dopaminergic neurons triggers the activation of microglia and harmful inflammatory processes that further amplify neuronal death. Recently, we demonstrated that the deletion of collapsin response mediator protein 4 (CRMP4) suppresses inflammatory responses and cell death in a mouse model of spinal cord injury, leading to improved functional recovery. We thus hypothesized that Crmp4-/- mice may have limited inflammatory responses and a decrease in the loss of SNc dopaminergic neurons in an 1-methyl-4-phenyl-1,2,3,6-tetrahydropyridine (MPTP)-induced PD mouse model. We observed CRMP4 expression in neurons, astrocytes, and microglia/macrophages following the injection of 25mg/kg MPTP. We compared the number of dopaminergic neurons and the inflammatory response in SNc between Crmp4+/+ and Crmp4-/- mice after MPTP injection. Limited loss of SNc dopaminergic neurons and decreased activations of microglia and astrocytes were observed in Crmp4-/- mice. These results suggest that CRMP4 is a novel therapeutic target in the treatment of PD patients. We demonstrated that genetic CRMP4 deletion delays a vicious cycle of inflammation and neurodegeneration in a Parkinson's disease mouse model. MPTP (1-methyl-4-phenyl-1,2,3,6-tetrahydropyridine) injection to wild-type mice induces collapsin response mediator protein 4 (CRMP4) up-regulation in neurons, astrocytes, and microglia. CRMP4-deficient mice show reduced inflammation and suppressed dopaminergic neuronal death after MPTP injection. These findings suggest that CRMP4 deletion may be a new therapeutic strategy against Parkinson's diseases.