CRMP-5 neuronal autoantibody: marker of lung cancer and thymoma-related autoimmunity

We have defined a new paraneoplastic immunoglobulin G (IgG) autoantibody specific for CRMP-5, a previously unknown 62-kd neuronal cytoplasmic protein of the collapsin response-mediator family. CRMP-5 is in adult central and peripheral neurons, including synapses, and in small-cell lung carcinomas. Since 1993, our Clinical Neuroimmunology Laboratory has detected CRMP-5-IgG in 121 patients among approximately 68,000 whose sera were submitted for standardized immunofluorescence screening because a subacute neurological presentation was suspected to be paraneoplastic. This makes CRMP-5 autoantibody as frequent as PCA-1 (anti-Yo) autoantibody, second only to ANNA-1 (anti-Hu). Clinical information, obtained for 116 patients, revealed multifocal neurological signs. Most remarkable were the high frequencies of chorea (11%) and cranial neuropathy (17%, including 10% loss of olfaction/taste, 7% optic neuropathy). Other common signs were peripheral neuropathy (47%), autonomic neuropathy (31%), cerebellar ataxia (26%), subacute dementia (25%), and neuromuscular junction disorders (12%). Spinal fluid was inflammatory in 86%, and CRMP-5-IgG in 37% equaled or significantly exceeded serum titers. Lung carcinoma (mostly limited small-cell) was found in 77% of patients; thymoma was in 6%. Half of those remaining had miscellaneous neoplasms; all but two were smokers. Serum IgG in all cases bound to recombinant CRMP-5 (predominantly N-terminal epitopes), but not to human CRMP-2 or CRMP-3.     

Antibody to collapsin response mediator protein 1 promotes neurite outgrowth from rat hippocampal neurons

This study examined the role of collapsin response mediator protein 1 (CRMP-1) on neurite outgrowth from rat hippocampal neurons by blocking its function using an antibody.Hippocampal neurons,cultured in vitro,were treated (blocked) using a polyclonal antibody to CRMP-1,and neurite outgrowth and cytoskeletal changes were captured using atomic force microscopy and laser confocal microscopy.Control cells,treated with normal rabbit IgG,established their characteristic morphology and had a large number of proce...     

Paraneoplastic autoimmune optic neuritis with retinitis defined by CRMP-5-IgG

Autoantibodies have defined two paraneoplastic visual disorders related to small-cell lung carcinoma: retinopathy ("CAR"-IgG [23kDa, recoverin]) and optic neuritis collapsin response-mediated protein 5 (CRMP-5-IgG [62kDa]). Among 16 patients with CRMP-5-IgG and optic neuritis (aged 52-74 years; all smokers, 9 women), we documented coexisting retinitis in 5. None had CAR-IgG. Fifteen had subacute vision loss, swollen optic discs, and field defects. Vascular leakage was evident at and remote from the disc; 5/5 tested had abnormal electroretinograms. Nine had striking vitreous cells. Vitrectomy showed reactive lymphocytosis (4/4), predominantly CD4(+) (1/1). Most patients had multifocal neurological accompaniments. Cerebrospinal fluid contained lymphocytes (7-32), elevated protein, multiple oligoclonal immunoglobulin bands, and CRMP-5-IgG. Three patients superficially resembled Devic's disease at presentation. One autopsied patient had predominantly CD8(+) T lymphocytes infiltrating optic nerve and spinal cord. Eleven patients had confirmed small-cell carcinoma; 1 had imaging evidence of lung cancer; 3 had renal or thyroid carcinoma. Full-length CRMP-5 protein was identified in normal retina and optic nerve by Western blot analyses. Photoreceptor cells, retinal ganglion cells, and nerve fibers exhibited CRMP-5-specific immunoreactivity. In summary, CRMP-5-IgG defines a paraneoplastic ophthalmological entity of combined optic neuritis and retinitis with vitreous inflammatory cells. Positive serology obviates the need for vitreous biopsy and expedites the search for cancer.     

Orthostatic hypotension secondary to CRMP-5 paraneoplastic autonomic neuropathy

The collapsin response mediator protein 5 (CRMP-5) autoantibody is one of only several paraneoplastic antibodies associated with autonomic neuropathy. Such paraneoplastic neuropathies manifest with a constellation of autonomic abnormalities. We present a unique case of orthostatic hypotension as the sole feature of a CRMP-5 paraneoplastic autonomic neuropathy in a patient with small cell lung cancer. Given the poor prognosis of paraneoplastic autonomic dysfunction, it is important to accurately diagnose the cause of orthostatic hypotension occurring on a background of malignancy.     

CRMP-4 expression in the adult cerebral cortex and other telencephalic areas of the lizard Podarcis hispanica

The control of neuritogenesis is crucial for the development, maturation and regeneration of the nervous system. The collapsin response-mediated protein 4 (CRMP-4) is a member of a family of proteins that are involved in neuronal differentiation and axonal outgrowth. In rodents, this protein is expressed in recently generated neurons such as some granule neurons of the dentate gyrus, as well as in certain differentiated neurons undergoing neurite outgrowth or synaptogenesis during adulthood. Since CRMP-4 protein appears to be highly conserved throughout the evolutionary scale, we have used immunocytochemistry to study its distribution in the lizard cerebral cortex. We have found pronounced CRMP-4 immunolabeling in certain neurons of the medial cortex, the homologous region to the dentate gyrus, but also in the dorsal and lateral cortices. Double labeling with 5'-BrdU indicated that these medial cortex neurons were recently generated. However, it is also possible that many of these cells were not new but undergoing some kind of plasticity implicating neurite outgrowth. Similar CRMP-4-labeled neurons and processes were observed in subcortical regions as the PDVR and the nucleus sphericus. Our results show for the first time the expression of CRMP-4 in a reptile brain, where it appears to be expressed in regions where adult neurogenesis and/or neurite outgrowth occur.     

Collapsin response mediator protein-4 (CRMP-4) expression in posthaching development of song control nuclei in Bengalese finches

CRMP-4 is regarded to play a role in neuronal differentiation, neurite growth and synapse formation. It has been shown to express in brain areas undergoing plastic changes or neuronal generation. Bird song is a learned, complex behavior. During song learning, some neural changes occur dramatically within song nuclei in neuron number, neuronal morphology, and synaptic formation or rearrangements. In order to get insights into the potential functions of CRMP-4 in the posthatching development of song nuclei during song learning, we examined the expression of CRMP-4 protein and mRNA in song control nuclei of Bengalese finch (Lonchura striata) from posthatching days (P) 10 to adulthood. Our study showed that cells positive for CRMP-4 protein and mRNA were distributed in song nuclei nearly in all the studied groups. The numbers of CRMP-4 cells in most of studied song nuclei changed significantly with age. They reached the peak at P15 in the lateral magnocellular nucleus of anterior nidopallium (LMAN) and the caudal medial nidopallium (NCM), or at P25 in HVC, Area X and the dorsolateral nucleus of the medial anterior thalamus (DLM). They then continued to decrease till adulthood. CRMP-4 protein and mRNA were both relatively high expressed during the post-hatch development of song control nuclei and song learning (P20-60), suggesting that CRMP-4 is involved in these activities. Although CRMP-4 protein and mRNA largely decreased at adulthood, they continued to express moderately, revealing that CRMP-4 may play a role in the maintenance of adult song nuclei.     

Paraneoplastic encephalomyelopathies: pathology and mechanisms

The last three decades have seen major advances in the understanding of paraneoplastic and idiopathic autoimmune disorders affecting the central nervous system (CNS). Neural-specific autoantibodies and their target antigens have been discovered, immunopathology and neuroimaging patterns recognized and pathogenic mechanisms elucidated. Disorders accompanied by autoantibody markers of neural peptide-specific cytotoxic effector T cells [such as anti-neuronal nuclear antibody type 1 (ANNA-1, aka anti-Hu), Purkinje cell antibody type 1 (PCA-1, aka anti-Yo) and CRMP-5 IgG] are generally poorly responsive to immunotherapy. Disorders accompanied by neural plasma membrane-reactive autoantibodies [the effectors of synaptic disorders, which include antibodies targeting voltage-gated potassium channel (VGKC) complex proteins, NMDA and GABA-B receptors] generally respond well to early immunotherapy. Here we describe in detail the neuropathological findings and pathophysiology of paraneoplastic CNS disorders with reference to antigen-specific serology and neurological and oncological contexts.     

Calpain-mediated cleavage of collapsin response mediator protein(CRMP)-2 during neurite degeneration in mice

Axon or dendrite degeneration involves activation of the ubiquitin-proteasome system, failure to maintain neuritic ATP levels, microtubule fragmentation and a mitochondrial permeability transition that occur independently of the somal death programs. To gain further insight into the neurite degeneration mechanims we have compared two-dimensional gel electrophoresis patterns of neurite proteins from suprior cervical ganglia during degeneration caused by nerve growth factor (NGF) deprivation. We show here that collapsin response mediator protein (CRMP)-2 and CMRP-4 protein patterns were altered during beading formation, an early hallmark of neurite degeneration, prior to neurite fragmentation, the final stage of degeneration. Western blotting using a monoclonal antibody against CRMP-2 shows that the native form (64 kDa) was cleaved to generate a truncated form (58 kDa). No cleavage of CRMP-2 or -4 occurred in NGF-deprived neurites from Wld(s) (Wallerian degeneration slow) mutant mice in which neurite degeneration is markedly delayed. Using different protease inhibitors, purified calpain 1 protein and calpain 1-specific siRNA, we have demonstrated that CRMP-2 is a substrate for calpain 1. Indeed, caplain activity was activated at an early phase of neuronal degeneration in cerebellar granule neurons, and down-regulation of caplain 1 expression suppressed CRMP-2 cleavage. Furthermore, this cleavage occurred after vinblastine treatment or in vitro Wallerian degeneration, suggesting that it represents a common step in the process of dying neurites. CRMP-2 and -4 play a pivotal role in axonal growth and transport, and the C-terminus region of CRMP-2 is essential for its binding to kinesin-1. Hence, this cleavage will render them dysfunctional and subject to autophagic processing associated with beading formation, as evidenced by the finding that the truncated form was localized in the beadings.     

Aberrant expression of collapsin response mediator proteins-1, -2 and -5 in the brain of intrauterine growth restricted rats

Intrauterine growth restriction (IUGR) has been associated with increased perinatal morbidity, higher incidence of neurodevelopmental defects and increased risk for adult metabolic syndrome manifestations. Altered protein expression profiles associated with IUGR may be informative on the pathological mechanisms of this condition and might reveal potential markers for postnatal complications. We hypothesized that nutrient manipulation of the pregnant rat might influence the expression of important neurodevelopmental proteins in the resultant IUGR offspring. Therefore, we aimed to determine in newborn rat brain tissue the expression of collapsin response mediator proteins (CRMPs)-1, -2 and -5, commonly referred to as dihydropyrimidinase-related proteins (DPYLs) – playing a role in axon guidance, invasive growth and cell migration – and compare it to the corresponding expression in control rats. Two-dimensional electrophoresis and mass spectrometry, as well as Western blot analysis were employed in brain tissue from 24 IUGR newborn rats and 24 controls. With both methods, CRMP-1, CRMP-2 and CRMP-5 were decreased in the brains of the IUGR group as compared to the control group at the time of delivery. In conclusion, IUGR rat offspring are born with a decreased expression of CRMPs, suggesting that these proteins may be implicated in fetal stress-induced programming.     

Paraneoplastic autoimmune movement disorders

Purpose of reviewTo provide an overview of paraneoplastic autoimmune disorders presenting with various movement disorders.Recent findingsThe spectrum of paraneoplastic autoimmune disorders has been expanding with the discovery of new antibodies against cell surface and intracellular antigens. Many of these paraneoplastic autoimmune disorders manifest as a form of movement disorder. With the discovery of new neuronal antibodies, an increasing number of idiopathic or neurodegenerative movement disorders are now being reclassified as immune-mediated movement disorders. These include anti-N-methyl-d-aspartate receptor (NMDAR) encephalitis which may present with orolingual facial dyskinesia and stereotyped movements, CRMP-5 IgG presenting with chorea, anti-Yo paraneoplastic cerebellar degeneration presenting with ataxia, anti-VGKC complex (Caspr2 antibodies) neuromyotonia, opsoclonus-myoclonus-ataxia syndrome, and muscle rigidity and episodic spasms (amphiphysin, glutamic acid decarboxylase, glycine receptor, GABA(A)-receptor associated protein antibodies) in stiff-person syndrome.SummaryMovement disorders may be a presentation for paraneoplastic autoimmune disorders. Recognition of these disorders and their common phenomenology is important because it may lead to the discovery of an occult malignancy.     

Expression patterns of immature neuronal markers PSA-NCAM,CRMP-4 and NeuroD in the hippocampus of young adult and aged rodents

Neurogenesis is known to continue in the adult hippocampus of mammals, including humans. The present experiments were undertaken to examine the nature of developing neurons generated in the dentate gyrus of young and older rodents using immature neuronal markers such as highly polysialylated neural cell adhesion molecules (PSA-NCAM), collapsin response-mediated protein-4 (CRMP-4) and NeuroD. Most PSA-expressing cells are simultaneously positive for CRMP-4 and NeuroD in young rats. More than half of the PSA-positive cells were also positive for mature neuronal markers such as NeuN and MAP2, although the intensity of the immunoreactivities was relatively weak. BrdU analysis revealed that CRMP-4 is expressed for a longer period than PSA in BrdU-labeled neurons. The number of immature neurons expressing PSA, NeuroD or CRMP-4 decreased in older rodents, but no qualitative difference was found in the expression patterns of these molecular markers between young and older rodents. These results suggest not only that immunohistochemistry, using a combination of these immature and mature neuronal markers, is helpful for clarifying the developmental state of newly generated neurons, but also that newly generated neurons in young adult and older rodents have similar properties.     

Small cell lung carcinoma presenting as collapsin response-mediating protein (CRMP) -5 paraneoplastic optic neuropathy.

A 77-year-old woman presenting with progressive visual loss in both eyes was found to have small cell lung cancer. Assay for collapsin response-mediating protein (CRMP) -5 was positive suggesting a paraneoplastic optic neuropathy (PON). During treatment of the small cell lung cancer, the patient died of pneumonia and autopsy disclosed neuropathologic abnormalities consistent with PON. This is only the second case of CRMP-5-confirmed PON to report neuropathologic findings.     

Paraneoplastic chorea with leukoencephalopathy presenting with obsessive-compulsive and behavioral disorder.

Chorea is a rare manifestation of paraneoplastic disease and is associated with CV2/CRMP-5 antibodies. Obsessive-compulsive disorder and large-scale white matter abnormalities on MRI have not been previously reported in association with these antibodies. We report on a case of CV2 paraneoplastic syndrome with obsessive-compulsive behavior preceding the motor manifestations of chorea with associated leukoencephalopathy on MRI. The literature on paraneoplastic chorea is reviewed.     

Antibody testing as a diagnostic tool in autonomic disorders

Some forms of peripheral autonomic dysfunction (especially enteric neuropathy and subacute panautonomic failure) occur as autoimmune phenomena either in isolation or in the context of cancer. Autoimmune autonomic ganglionopathy is an example of a severe, but potentially treatable, antibody-mediated form of autonomic failure. Diagnostic evaluation of autonomic disorders can be supplemented by testing for paraneoplastic antibodies and antibodies against membrane receptors. The diagnostic antibodies most commonly associated with dysautonomia are paraneoplastic antibodies (anti-Hu and CRMP-5) and ganglionic acetylcholine receptor antibodies.     

脑衰反应调节蛋白-2（CRMP-2）促进海马神经元轴突生长

目的研究脑衰反应调节蛋白2（collapsin response mediator protein,CRMP-2）对原代海马神经元轴突生长的影响,探讨CRMP-2在神经元轴突生成中的作用。方法每次原代取孕18d SD大鼠1只,每只孕鼠含胎鼠约12~15只。显微镜下分离12~15只胎鼠双侧海马组织,消化法培养原代海马神经元。原代海马神经元培养采用核电转实验转染绿色荧光蛋白（enhanced green fluorescence protein,EGFP）和野生型CRMP-2（wild type（wt）CRMP2）和突变型T514D-CRMP2（突变体,模拟失活型CRMP-2）。培养72h固定做免疫荧光双标,分别绿色荧光蛋白（EGFP）和轴突标志物Tau-1,采用激光共聚焦显微镜和普通光学显微镜观察海马神经元形态变化。结果转染EGFP载体的对照组神经元正常发育,培养至72h,神经元轴突特异性表达标志物蛋白Tau-1;过表达了wtCRMP-2的神经元除了生成一条长的特异性表达Tau-1的轴突,另外一条突起也发育成了特异性表达Tau-1的轴突;而过表达了失活型CRMP-2的神经元发育与正常组相比无差异。结论野生型CRMP-2可明显促进轴突生长,而转染模拟磷酸化CRMP-2的突变体T514D-CRMP2则没有显示任何的促进作用。     

Paraneoplastic chorea associated with CRMP-5 neuronal antibody and lung carcinoma

Paraneoplastic chorea is described in 16 patients: 11 with limited small-cell carcinoma, 2 with lung cancer revealed by imaging, 1 with renal cell carcinoma, and 1 with lymphoma. All had CRMP-5-IgG; 6 also had ANNA-1 (anti-Hu), including 1 without evident cancer. Chorea was the initial and most prominent symptom in 11 patients, asymmetric or unilateral in 5 patients, and part of a multifocal syndrome in 14 patients. Basal ganglia abnormalities were revealed by magnetic resonance imaging and at autopsy (as perivascular inflammation and microglial activation). Four patients improved with chemotherapy, and 2 improved with intravenous methylprednisolone.     

Anti-neuronal nuclear autoantibody type 2: paraneoplastic accompaniments

We identified the IgG autoantibody ANNA-2 ("anti-Ri") in 34 patients in a 12-year period by immunofluorescence screening of sera from approximately 75000 patients with subacute neurological disorders that were suspected to be paraneoplastic. Detailed clinical information was available for 28 patients (10 men, 18 women). Cancer was diagnosed in 24 patients (86%); 21 had histologically proven carcinoma (10 lung, 9 breast, 1 cervical, 1 bladder), and 3 had an intrathoracic imaging abnormality. Cancer anteceded neurological symptoms in 4 of 28 patients. Cancer detection frequency increased with continued surveillance. Neurological disorders, in decreasing frequency, were brainstem syndrome (including opsoclonus, myoclonus, or both), cerebellar syndrome, myelopathy, peripheral neuropathy, cranial neuropathy, movement disorder, encephalopathy, Lambert-Eaton syndrome, and seizures. Four patients had laryngospasm and four had jaw opening dystonia (two with neck dystonia). Nine (32%) were wheelchair-bound 1 month after neurological symptom onset. Most improved neurologically after immunomodulatory or tumor-directed therapy. Accompanying autoantibodies, found in 73% of sera, included ANNA-1, ANNA-3, CRMP-5-IgG, P/Q-type and N-type Ca(2+) channel antibodies, and muscle-type acetylcholine receptor antibody. Some neurological accompaniments of ANNA-2 may reflect potentially pathogenic humoral or cell-mediated responses to coimmunogenic tumor antigens, for example, Lambert-Eaton syndrome (P/Q-type Ca(2+) channel antibody) and peripheral neuropathy (ANNA-1 effector T cells).     

Age-related proteomic changes in the subventricular zone and their association with neural stem/progenitor cell proliferation

In the mammalian central nervous system, generation of new neurons persists in the subventricular zone (SVZ) throughout life. However, the capacity for neurogenesis in this region declines with aging. Recent studies have examined the degree of these age-related neurogenic declines and the changes of cytoarchitecture of the SVZ with aging. However, little is known about the molecular changes in the SVZ with aging. In this study, we dissected the SVZs from rats aged postnatal day 28, 3 months, and 24 months. The SVZ tissues were processed for 2-D gel electrophoresis to identify protein changes following aging. Protein spots were subsequently subjected to mass spectrometry analysis to compare age-related alterations in the SVZ proteome. We also examined the level of cell proliferation in the SVZ in animals of these three age groups by using bromodeoxyuridine labeling. We found significant age-related changes in the expression of several proteins that play critical roles in the proliferation and survival of neural stem/progenitor cells in the SVZ. Among these proteins, glial fibrillary acidic protein, ubiquitin carboxy terminal hydrolase 1, glutathione S-transferase omega, and preproalbumin were increased with aging, whereas collapsin response-mediated protein 4 (CRMP-4), CRMP-5, and microsomal protease ER60 exhibited declines with aging. We have also observed a significant decline of neural stem/progenitor cell proliferation in the SVZ with aging. These alterations in protein expression in the SVZ with aging likely underlie the diminishing proliferative capacity of stem/progenitor cells in the aging brain.     

Paraneoplastic optic neuropathy and cerebellar ataxia with small cell carcinoma of the lung.

Bilateral optic neuropathy and subacute cerebellar ataxia were manifestations of a paraneoplastic neurologic disorder in a woman found to have small cell carcinoma of the lung. Serologic tests revealed a neuronal autoantibody specific for CRMP-5, a 62-kd member of the collapsin response-mediating protein family. Unexplained optic neuropathy in the setting of subacute cerebellar ataxia should cause suspicion of a paraneoplastic disorder and prompt testing for this autoantibody, especially in patients at risk for lung carcinoma.     

Whole-body tremulousness: isolated generalized polymyoclonus

BACKGROUND: Acquired generalized repetitive myoclonus may be mistaken for tremor. Distinguishing myoclonus has etiologic and therapeutic implications. OBJECTIVE: To describe isolated generalized polymyoclonus and the outcomes of etiologic evaluations at the time of diagnosis. DESIGN: Computer search of the Mayo Movement Neurophysiology Laboratory database and medical records linkage system. SETTING: Department of Neurology, Mayo Clinic. PATIENTS: Nineteen adults with generalized repetitive myoclonus confirmed using surface electromyography (burst duration <50 milliseconds), and other neurologic features minimal or absent. INTERVENTIONS: Treatment of myoclonus and underlying causes. MAIN OUTCOME MEASURES: Clinical presentation and underlying etiologies. RESULTS: We identified 19 patients with isolated generalized polymyoclonus resembling whole-body tremor. Onset was most often subacute (12 patients), mean symptom duration was 1.8 years, and mean age at onset was 55 years. Referral diagnoses or patient complaints were tremor, tremulousness, or shaking in all but 5 patients. All the patients had repetitive myoclonus of all limbs, impairing gait in 14 patients. Surface electromyography confirmed nonperiodic muscle burst durations of less than 50 milliseconds, typical of myoclonus. Clinical and serologic screening for cancer and autoimmunity revealed metastatic breast cancer in 2 patients (1 positive for ganglionic acetylcholine receptor antibody) and antibody profiles implicating neurologic autoimmunity in 3 patients (CRMP-5 IgG or neuronal voltage-gated potassium channel antibodies). Medications known to occasionally trigger myoclonus (opioids, selective serotonin reuptake inhibitors, and a serotonin-norepinephrine reuptake inhibitor) were being taken by 7 patients. Myoclonus resolved after discontinuation of selective serotonin reuptake inhibitor therapy in 1 patient; drug discontinuation was declined and follow-up was inadequate in the other 6. CONCLUSIONS: Isolated whole-body tremulousness should raise the suspicion of generalized polymyoclonus, confirmed using routine surface electromyography. Recognition is important because the differential diagnosis includes autoimmunity and drug-induced myoclonus.