PGP9.5, a ubiquitin C-terminal hydrolase; pattern of mRNA and protein expression during neural development in the mouse

A biochemical feedback signal for hypothermia treatment for neonatal hypoxic-ischemic encephalopathy: focusing on central nervous system proteins in biofluids

Hypothermia has been widely used to treat moderate to severe neonatal hypoxic-ischemic encephalopathy (HIE), yet evaluating the effects of hypothermia relies on clinical neurology, neuroimaging, amplitude-integrated electroencephalography, and follow-up data on patient outcomes. Biomarkers of brain injury have been considered for estimating the effects of hypothermia. Proteins specific to the central nervous system (CNS) are components of nervous tissue, and once the CNS is damaged, these proteins are released into biofluids (cerebrospinal fluid, blood, urine, tears, saliva), and they can be used as markers of brain damage. Clinical reports have shown that CNS-specific marker proteins (CNSPs) were early expressed in biofluids after brain damage and formed unique biochemical profiles. As a result, these markers may serve as an indicator for screening brain injury in infants, monitoring disease progression, identifying damage region of brain, and assessing the efficacy of neuroprotective measures. In clinical work, we have found that there are few reports on using CNSPs as biological signals in hypothermia for neonatal HIE. The aim of this article is to review the classification, origin, biochemical composition, and physiological function of CNSPs with changes in their expression levels after hypothermia for neonatal HIE. Hopefully, this review will improve the awareness of CNSPs among pediatricians, and encourage future studies exploring the mechanisms behind the effects of hypothermia on these CNSPs, in order to reduce the adverse outcome of neonatal HIE.

Digenic FLNA and UCHL1 variants resulting in a complex phenotype

AIM

X-linked variants in Filamin A (FLNA) are associated with the Ehlers-Danlos-syndrome-variant form of periventricular heterotopia, and autosomal dominant variants in ubiquitin C-terminal hydrolase L1 (UCHL1) are associated with a late-onset spastic ataxia, peripheral neuropathy and optic atrophy. Here we present a rare case involving both a novel heterozygous whole-gene deletion of UCHL1 and a heterozygous frameshift variant in the FLNA gene resulting in a complex phenotype.

METHODS

A 67-year-old female with a confirmed pathogenic variant in the FLNA gene, resulting in an enlarged aorta and joint pains, presented with a 4-year history of severe sensory ataxia, upper motor neuron signs, eye movement abnormalities and severe sensory loss.

RESULTS

Neurophysiology including Somatosensory-evoked potentials confirmed the sensory loss as predominantly preganglionic with denervation. Genetic testing revealed a digenic cause of her complex presentation, confirming a pathogenic frameshift variant in the FLNA gene and a heterozygous loss of function deletion in the UCHL1 gene.

CONCLUSIONS

To the best of our knowledge, this is the first case with concomitant pathogenic variants in the FLNA and UCHL1 genes which explain the complex phenotype. The severe preganglionic sensory loss is also a rare finding and expands the phenotype of UCHL1 variants.

Musclin prevents depression-like behavior in male mice by activating urocortin 2 signaling in the hypothalamus

Introduction

Physical activity is recommended as an alternative treatment for depression. Myokines, which are secreted from skeletal muscles during physical activity, play an important role in the skeletal muscle-brain axis. Musclin, a newly discovered myokine, exerts physical endurance, however, the effects of musclin on emotional behaviors, such as depression, have not been evaluated. This study aimed to access the anti-depressive effect of musclin and clarify the connection between depression-like behavior and hypothalamic neuropeptides in mice.

Methods

We measured the immobility time in the forced swim (FS) test, the time spent in open arm in the elevated-plus maze (EPM) test, the mRNA levels of hypothalamic neuropeptides, and enumerated the c-Fos-positive cells in the paraventricular nucleus (PVN), arcuate nucleus (ARC), and nucleus tractus solitarii (NTS) in mice with the intraperitoneal (i.p.) administration of musclin. Next, we evaluated the effects of a selective corticotropin-releasing factor (CRF) type 1 receptor antagonist, selective CRF type 2 receptor antagonist, melanocortin receptor (MCR) agonist, and selective melanocortin 4 receptor (MC4R) agonist on changes in behaviors induced by musclin. Finally we evaluated the antidepressant effect of musclin using mice exposed to repeated water immersion (WI) stress.

Results

We found that the i.p. and i.c.v. administration of musclin decreased the immobility time and relative time in the open arms (open %) in mice and increased urocortin 2 (Ucn 2) levels but decreased proopiomelanocortin levels in the hypothalamus. The numbers of c-Fos-positive cells were increased in the PVN and NTS but decreased in the ARC of mice with i.p. administration of musclin. The c-Fos-positive cells in the PVN were also found to be Ucn 2-positive. The antidepressant and anxiogenic effects of musclin were blocked by central administration of a CRF type 2 receptor antagonist and a melanocortin 4 receptor agonist, respectively. Peripheral administration of musclin also prevented depression-like behavior and the decrease in levels of hypothalamic Ucn 2 induced by repeated WI stress.

Discussion

These data identify the antidepressant effects of musclin through the activation of central Ucn 2 signaling and suggest that musclin and Ucn 2 can be new therapeutic targets and endogenous peptides mediating the muscle-brain axis.

Malocclusion impairs cognitive behavior via AgRP signaling in adolescent mice

Introduction

Occlusal disharmony induced by deteriorating oral health conditions, such as tooth loss and decreased masticatory muscle due to sarcopenia, is one of the causes of cognitive impairment. Chewing is an essential oral function for maintaining cognitive function not only in the elderly but also in young people. Malocclusion is an occlusal disharmony that commonly occurs in children. The connection between a decline in cognitive function and malocclusion in children has been shown with chronic mouth breathing, obstructive sleep apnea syndrome, and thumb/digit sucking habits. However, the mechanism of malocclusion-induced cognitive decline is not fully understood. We recently reported an association between feeding-related neuropeptides and cognitive decline in adolescent mice with activity-based anorexia. The aim of the present study was to assess the effects of malocclusion on cognitive behavior and clarify the connection between cognitive decline and hypothalamic feeding-related neuropeptides in adolescent mice with malocclusion.

Methods

Four-week-old mice were randomly assigned to the sham-operated solid diet-fed (Sham/solid), sham-operated powder diet-fed (Sham/powder), or malocclusion-operated powder diet-fed (Malocclusion/powder) group. We applied composite resin to the mandibular anterior teeth to simulate malocclusion. We evaluated cognitive behavior using a novel object recognition (NOR) test, measured hypothalamic feeding-related neuropeptide mRNA expression levels, and enumerated c-Fos-positive cells in the hypothalamus 1 month after surgery. We also evaluated the effects of central antibody administration on cognitive behavior impairment in the NOR test.

Results

The NOR indices were lower and the agouti-related peptide (AgRP) mRNA levels and number of c-Fos-positive cells were higher in the malocclusion/powder group than in the other groups. The c-Fos-positive cells were also AgRP-positive. We observed that the central administration of anti-AgRP antibody significantly increased the NOR indices.

Discussion

The present study suggests that elevated cerebral AgRP signaling contributes to malocclusion-induced cognitive decline in adolescents, and the suppression of AgRP signaling can be a new therapeutic target against cognitive decline in occlusal disharmony.

Genome-wide analysis of genes encoding core components of the ubiquitin system during cerebral cortex development

Ubiquitination involves three types of enzymes (E1, E2, and E3) that sequentially attach ubiquitin (Ub) to target proteins. This posttranslational modification controls key cellular processes, such as the degradation, endocytosis, subcellular localization and activity of proteins. Ubiquitination, which can be reversed by deubiquitinating enzymes (DUBs), plays important roles during brain development. Furthermore, deregulation of the Ub system is linked to the pathogenesis of various diseases, including neurodegenerative disorders. We used a publicly available RNA-seq database to perform an extensive genome-wide gene expression analysis of the core components of the ubiquitination machinery, covering Ub genes as well as E1, E2, E3 and DUB genes. The ubiquitination network was governed by only Uba1 and Ube2m, the predominant E1 and E2 genes, respectively; their expression was positively regulated during cortical formation. The principal genes encoding HECT (homologous to the E6-AP carboxyl terminus), RBR (RING-in-between-RING), and RING (really interesting new gene) E3 Ub ligases were also highly regulated. Pja1, Dtx3 (RING ligases) and Stub1 (U-box RING) were the most highly expressed E3 Ub ligase genes and displayed distinct developmental expression patterns. Moreover, more than 80 DUB genes were expressed during corticogenesis, with two prominent genes, Uch-l1 and Usp22, showing highly upregulated expression. Several components of the Ub system overexpressed in cancers were also highly expressed in the cerebral cortex under conditions not related to tumour formation or progression. Altogether, this work provides an in-depth overview of transcriptomic changes during embryonic formation of the cerebral cortex. The data also offer new insight into the characterization of the Ub system and may contribute to a better understanding of its involvement in the pathogenesis of neurodevelopmental disorders.

A single cell transcriptomics map of paracrine networks in the intrinsic cardiac nervous system

We developed a spatially-tracked single neuron transcriptomics map of an intrinsic cardiac ganglion, the right atrial ganglionic plexus (RAGP) that is a critical mediator of sinoatrial node (SAN) activity. This 3D representation of RAGP used neuronal tracing to extensively map the spatial distribution of the subset of neurons that project to the SAN. RNA-seq of laser capture microdissected neurons revealed a distinct composition of RAGP neurons compared to the central nervous system and a surprising finding that cholinergic and catecholaminergic markers are coexpressed, suggesting multipotential phenotypes that can drive neuroplasticity within RAGP. High-throughput qPCR of hundreds of laser capture microdissected single neurons confirmed these findings and revealed a high dimensionality of neuromodulatory factors that contribute to dynamic control of the heart. Neuropeptide-receptor coexpression analysis revealed a combinatorial paracrine neuromodulatory network within RAGP informing follow-on studies on the vagal control of RAGP to regulate cardiac function in health and disease.

Immunohistochemical Investigation of Autonomic and Sensory Innervation of Anterior Vaginal Wall Female Periurethral Tissue: A Study of the Surgical Field of Mid-Urethral Sling Surgery Using Cadaveric Simulation

BACKGROUND

Female sexual dysfunction, including female orgasm disorder, has been reported following mid-urethral sling (MUS) surgery to treat bothersome stress urinary incontinence. Anterior vaginal wall-female periurethral tissue (AVW-FPT) likely contains autonomic and sensory innervation involved in the female sexual response, and injury to these nerves may result from MUS implantation.

AIM

To characterize, using fresh cadaveric tissue, autonomic and sensory nerves in AVW- FPT using immunohistochemistry (IHC), and to assess their proximity to an implanted MUS.

METHODS

AVW-FPT was excised following careful dissection from four fresh cadavers. Prior to dissection, one cadaver underwent simulation of the MUS procedure by a urogynegologist, using a fascial sling. All samples were paraffin embedded, sectioned, and stained with hematoxylin. Serial sectioning and IHC were performed to identify nerves. IHC markers were used to characterize the sensory and autonomic innervation.

OUTCOMES

IHC localization of autonomic and sensory nerve markers consistent with neural tissue within the region of MUS implantation.

RESULTS

IHC of AVW-FPT using protein gene product 9.5 (PGP9.5), a general nerve stain, revealed innervation throughout the region targeted by the MUS implantation. More specifically, immunoreactivity for both autonomic (tyrosine hydroxylase, TH) and sensory (Na_v1.8 and S100ß) nerves were found in close proximity (<1 mm) to the implanted MUS. In addition, a subset of S100ß positive nerves also showed immunoreactivity for calcitonin gene-related peptide (CGRP). Combining the IHC findings with the surgical simulation of the MUS implantation revealed the potential for damage to both autonomic and sensory nerves as a direct result of the MUS procedure.

CLINICAL TRANSLATION

The identified autonomic and sensory nerves of the AVW-FPT may contribute to the female sexual response, and yet are potentially negatively impacted by MUS procedures. Given that surgeries performed on male genital tissue, including the prostate, may cause sexual dysfunction secondary to nerve damage, and that urologists routinely provide informed consent regarding this possibility, urogynaecologists are encouraged to obtain appropriate informed consent from prospective patients undergoing the MUS procedure.

STRENGTHS & LIMITATIONS

This is the first study to characterize the sensory and autonomic innervation within the surgical field of MUS implantation and demonstrate its relationship to an implanted MUS. The small sample size is a limitation of this study.

CONCLUSION

The present study provides evidence of potential injury to autonomic and sensory innervation of AVW-FPT as a consequence of MUS implantation, which may help explain the underlying mechanisms involved in the reported post-operative female sexual dysfunction in some women. Giovannetti O, Tomalty D, Gaudet D, et al. Immunohistochemical Investigation of Autonomic and Sensory Innervation of Anterior Vaginal Wall Female Periurethral Tissue: A Study of the Surgical Field of Mid-Urethral Sling Surgery Using Cadaveric Simulation. J Sex Med 2021;18:1168-1180.

The Human and Mouse Enteric Nervous System at Single-Cell Resolution

The enteric nervous system (ENS) coordinates diverse functions in the intestine but has eluded comprehensive molecular characterization because of the rarity and diversity of cells. Here we develop two methods to profile the ENS of adult mice and humans at single-cell resolution: RAISIN RNA-seq for profiling intact nuclei with ribosome-bound mRNA and MIRACL-seq for label-free enrichment of rare cell types by droplet-based profiling. The 1,187,535 nuclei in our mouse atlas include 5,068 neurons from the ileum and colon, revealing extraordinary neuron diversity. We highlight circadian expression changes in enteric neurons, show that disease-related genes are dysregulated with aging, and identify differences between the ileum and proximal/distal colon. In humans, we profile 436,202 nuclei, recovering 1,445 neurons, and identify conserved and species-specific transcriptional programs and putative neuro-epithelial, neuro-stromal, and neuro-immune interactions. The human ENS expresses risk genes for neuropathic, inflammatory, and extra-intestinal diseases, suggesting neuronal contributions to disease.

Disrupted local innervation results in less VIP expression in CF mice tissues

Vasoactive Intestinal Peptide (VIP) is the major physiological agonist of the Cystic Fibrosis Transmembrane conductance Regulator (CFTR) chloride channel activity. VIP functions as a neuromodulator and neurotransmitter secreted by neurons innervating all exocrine glands. VIP is also a potent vasodilator and bronchodilator that regulates exocrine gland secretions, contributing to local innate defense by stimulating the movement of water and chloride transport across intestinal and tracheobronchial epithelia. Previous human studies have shown that the rich intrinsic neuronal networks for VIP secretion around exocrine glands could be lost in tissues from patients with cystic fibrosis. Our research has since confirmed, in vitro and in vivo, the need for chronic VIP exposure to maintain functional CFTR chloride channels at the cell surface of airways and intestinal epithelium, as well as normal exocrine tissues morphology [1]. The goal of the present study was to examine changes in VIP in the lung, duodenum and sweat glands of 8- and 17-weeks old F508del/F508del mice and to investigate VIPergic innervation in the small intestine of CF mice, before important signs of the disease development. Our data show that a low amount of VIP is found in CF tissues prior to tissue damage. Moreover, we found a specific reduction in VIPergic and cholinergic innervation of the small intestine. The general innervation of the primary and secondary myenteric plexus was lost in CF tissues, with the presence of enlarged ganglionic cells in the tertiary layer. We propose that low amount of VIP in CF tissues is due to a reduction in VIPergic and cholinergic innervation and represents an early defect that constitutes an aggravating factor for CF disease progression.

Ubiquitin carboxy-terminal hydrolase L1 - physiology and pathology

Ubiquitin C-terminal hydrolase 1 (UCHL1) is an enzyme unique for its multiple activity - both ligase and hydrolase. UCHL1 was first identified as an abundant protein found in the brain and testes, however its expression is not limited to the neuronal compartment. UCHL1 is also highly expressed in carcinomas of various tissue origins, including those from brain, lung, breast, kidney, colon, prostate, pancreas and mesenchymal tissues. Loss-of-function studies and an inhibitor for UCHL1 confirmed the importance of UCHL1 for cancer therapy. So far biological significance of UCHL1 was described in the following processes: spermatogenesis, oncogenesis, angiogenesis, cell proliferation and differentiation in skeletal muscle, inflammation, tissue injury, neuronal injury and neurodegeneration.

Examination of skin lesions in rats with induced hyperthyroidism and hypothyroidism

We investigated the pathogenesis of skin lesions due to hypothyroidism and hyperthyroidism in rats. We used 30 rats allocated into hypothyroidism, hyperthyroidism and control groups. Blood samples were evaluated for levels of thyroid stimulating hormone (TSH), tri-iodothyronine (T3) and thyroxine (T4). Skin samples were examined for melan-A, lymphatic vessel endothelial hyaluronic acid receptor 1 (LYVE1), cluster of differentiation 31 (CD31), protein gene product 9.5 (PGP9.5), calretinin, chromogranin, synaptophysin and pancytokeratin. Histopathological examination of the skin sections revealed thickened epidermis in the hyperthyroidism group due to an increased number of cells, and a decreased number of hair follicles and epithelial cell rows in the epidermis with an increased number of fat cells in the dermis of the rats in the hypothyroidism group. No significant difference was observed in the immunoreactions of pancytokeratin, PGP9.5, CD31 and synaptophysin among the groups. The hyperthyroidism and hypothyroidism groups exhibited a marked increase in melan-A immunoreaction. Expression of LYVE-1, chromogranin and calretinin was increased in the hyperthyroidism group and decreased in the hypothyroidism group. We found that melan-A, LYVE-1, chromogenin and calretinin play an important role in the pathogenesis of skin lesions caused by thyroid disorders.

Protein knots provide mechano-resilience to an AAA+ protease-mediated proteolysis with profound ATP energy expenses

Knotted proteins are some of the most fascinating examples of how linear polypeptide chains can achieve intricate topological arrangements efficiently and spontaneously. The entanglements of polypeptide chains could potentially enhance their folding stabilities. We recently reported the unprecedented mechanostability of the Gordian (5₂) knotted family of human ubiquitin C-terminal hydrolases (UCHs) in the context of withstanding the mechanical unfolding of the bacterial AAA+ proteasome, ClpXP; a green fluorescence protein (GFP) was fused to the N-terminus of various UCHs as a reporter of the unfolding and degradation of these topologically knotted substrates, but it also limited the ability to examine the effect of untying the knotted topology via N-terminal truncation. In this study, we directly monitored the ClpXP-mediated degradation of UCH variants by electrophoresis and quantitative imaging analyses. We demonstrated that untying of the 5₂ knot in UCHL1 via N-terminal truncation (UCHL1_Δ11) significantly reduces its mechanostability. We further quantified the ATP expenditures of degrading different UCH variants by ClpXP. The unknotted UCHL1_Δ11 underwent accelerated ClpXP-dependent proteolysis, with a 30-fold reduction in ATP consumption compared to the knotted wild type. Unlike all other known ClpXP substrates, UCHL5, which is the most resilient substrate known to date, significantly slowed down the ATP turnover rate by ClpXP. Furthermore, UCHL5 required 1000-fold more ATP to be fully degraded by ClpXP compared to GFP. Our results underscored how the complex, knotted folding topology in UCHs may interfere with the mechano-unfolding processes of the AAA+ unfoldase, ClpX.

Placental clearance/synthesis of neurobiomarkers GFAP and UCH-L1 in healthy term neonates and those with moderate-severe neonatal encephalopathy

BACKGROUND

Fetal concentrations of GFAP and UCH-L1 are elevated in umbilical arterial (UmA) blood of neonates with birth asphyxia plus neonatal encephalopathy (NE), but their source and role of placental clearance/synthesis is unknown.

METHODS

Prospective cohort study of term neonates to (a) determine UmA and venous (UmV) blood concentrations of GFAP and UCH-L1 in term uncomplicated pregnancies and their placental synthesis and/or clearance and (b) compare UmA concentrations in uncomplicated pregnancies with those complicated by fetal hypoxia-asphyxia+NE. Three term groups were studied: uncomplicated cesarean delivery without labor (Group 1, n = 15), uncomplicated vaginal delivery with labor (Group 2, n = 15), and perinatal hypoxia-asphyxia+NE (Group 3, n = 8).

RESULTS

UmA GFAP concentrations were lower in Group 1 vs. 2 (P = 0.02) and both demonstrated 100% placental clearance. In contrast, UmA and UmV UCH-L1 concentrations were not unaffected by labor. Group 3 UmA GFAP concentrations were 30- and 8-fold higher than Groups 1 and 2, respectively, P = 0.02, whereas UmA UCH-L1 concentrations were similar in all groups.

CONCLUSIONS

UmA GFAP is derived from the fetus, and circulating levels, which are modulated by placental clearance, increase during uncomplicated labor and more so in the presence of fetal hypoxia-asphyxia+NE, providing a better biomarker than UCH-L1 for hypoxia-asphyxia+NE.

Novel UCHL1 mutations reveal new insights into ubiquitin processing

Recessive loss of function of the neuronal ubiquitin hydrolase UCHL1 has been implicated in early-onset progressive neurodegeneration (MIM no. 615491), so far only in one family. In this study a second family is characterized, and the functional consequences of the identified mutations in UCHL1 are explored. Three siblings developed childhood-onset optic atrophy, followed by spasticity and ataxia. Whole exome sequencing identified compound heterozygous variants in UCHL1, c.533G > A (p.Arg178Gln) and c.647C > A (p.Ala216Asp), cosegregating with the phenotype. Enzymatic activity of purified recombinant proteins analysed by ubiquitin hydrolase assays showed a 4-fold increased hydrolytic activity of the recombinant UCHL1 mutant Arg178Gln compared to wild type, whereas the Ala216Asp protein was insoluble. Structural 3D analysis of UCHL1 by computer modelling suggests that Arg178 is a rate-controlling residue in catalysis which is partly abolished in the Arg178Gln mutant and, consequently, the Arg178Gln mutant increases the enzymatic turnover. UCHL1 protein levels in fibroblasts measured by targeted mass spectrometry showed a total amount of UCHL1 in control fibroblasts about 4-fold higher than in the patients. Hence, studies of the identified missense variants reveal surprisingly different functional consequences as the insoluble Ala216Asp variant leads to loss of function, whereas the Arg178Gln leads to increased enzyme activity. The reported patients have remarkably preserved cognition, and we propose that the increased enzyme activity of the Arg178Gln variant offers a protective effect on cognitive function. This study establishes the importance of UCHL1 in neurodegeneration, provides new mechanistic insight about ubiquitin processing, and underlines the complexity of the different roles of UCHL1.

Human Heart Glutamate Receptors—Implications for Toxicology, Food Safety, and Drug Discovery

Excitatory amino acids (EAAs) mediate their effects through the glutamate receptors (GluRs) in the brain. GluRs play an important role in the treatment of a variety of neuropsychiatric conditions and are central to the neurotoxicity of EAAs such as domoic and kainic acid. Unstained histological preparations of human heart tissues were used for the histopathological assessment, the anatomical identification of specific cardiac structures and the presence of the GluRs. Immunohistochemical stains with the biomarkers protein gene product (PGP 9.5) and the neurofilaments (NF 160 and NF 200) were used to identify neural structures and the components of the conducting system. Several subtypes of GluRs were differentially expressed and each had a specific distribution. In contrast to nonhuman primates, GluRs are more widely expressed in humans, where the working myocardium and the wall of blood vessels stained for GluRs. The immunolabelling was observed within the specialized structures of the conducting system, intramural nerves, and ganglia cells. These receptors may be involved in important cardiac functions such as contraction, rhythm, coronary circulation, and thus may be implicated in the pathobiology of some cardiac disease. The GluRs in the heart could be targets for the effects of excitatory compounds and is therefore an important consideration for the safety evaluation of foods and therapeutic products.

Morphological Analysis for Neuron-Like Cells in the Vomeronasal Organ of Human Fetuses at the Middle of Gestation

The vomeronasal organ (VNO) of 5-month-old fetuses was examined immunohistochemically by the use of an antiserum to protein gene product 9.5 (PGP). The purpose was to identify if the human fetal VNO is lined by neuroepithelium. The PGP antiserum labeled abundant cells within the vomeronasal epithelium (VE), nerve fiber bundles in its lamina propria, and cells associated with these bundles. PGP-immunoreactive (ir) vomeronasal epithelial cells were classified into three subtypes. Type I cells, about 44% of the total cells observed, did not have any processes and tended to be located in the basal layer of the VE. Type II cells, about 37% had a single apical process that projected toward the lumen, ending at the epithelial surface. Type III cells sent a prominent process mainly toward the basement membrane, and occupied about 19% of the total cells observed. In the lamina propria, a considerable number of PGP-ir cells was observed. Some of them were present in nerve fiber bundles and contained processes parallel to the bundles. In addition, PGP-ir nerve fiber bundles and cells associated with them were even present in the portion of the nasal septal mucosa that was very close to the brain. The present results strongly suggested that the VE in human fetuses at mid-gestation is a neuroepithelium and that the VE may produce migrating cells toward the brain.

Neonatal hypoxic ischemic encephalopathy-related biomarkers in serum and cerebrospinal fluid

Neonatal hypoxic ischemic encephalopathy (HIE) is a common disease caused by perinatal asphyxia, a major cause of neonatal death, neurological behavior, and long-term disability. Currently, the diagnosis and prognosis of neonatal HIE are based on nervous system clinical manifestations, imaging and electrophysiological examination. These take time and late diagnosis allows brain injury to occur in newborns, so that infants of many brain injury missed the best treatment time, left with varying degrees of neurological sequelae. The use of biomarkers to monitor brain injury and evaluate neuroprotective effects might allow the early intervention and treatment of neonatal HIE to reduce mortality rates. This study reviewed the mechanism of neonatal hypoxic ischemic encephalopathy in relation to numerous brain-related biomarkers including NSE, S-100β, GFAP, UCH-L1, Tau protein, miRNA, LDH, and CK-BB. In early diagnosis of neonatal HIE, S-100β and activin A seems to be better biomarkers. Biomarkers with the greatest potential to predict long-term neurologic handicap of neonates with HIE are GFAP and UCH-L1 and when combined with other markers or brain imaging can increase the detection rate of HIE. Tau protein is a unique biological component of nervous tissues, and might have value for neonatal HIE diagnosis. Combination of more than two biological markers should be a future research direction.

Could dysregulation of UPS be a common underlying mechanism for cancer and neurodegeneration? Lessons from UCHL1

Ubiquitin proteasome system (UPS) determines the timing and extent of protein turnover in cells, and it is one of the most strictly controlled cellular mechanisms. Lack of proper control over UPS is attributed to both cancer and to neurodegenerative diseases, yet in different context and direction. Cancerous cells have altered cellular metabolisms, uncontrolled cellular division, and increased proteasome activity. The specialized function prevent neurons from undergoing cellular division but allow them to extend an axon over long distances, establish connections, and to form stable neuronal circuitries. Neurons heavily depend on the proper function of the proteasome and the UPS for their proper function. Reduction of UPS function in vulnerable neurons results in protein aggregation, increased ER stress, and cell death. Identification of compounds that selectively block proteasome function in distinct set of malignancies added momentum to drug discovery efforts, and deubiquitinases (DUBs) gained much attention. This review will focus on ubiquitin carboxy-terminal hydrolase L1 (UCHL1), a DUB that is attributed to both cancer and neurodegeneration. The potential of developing effective treatment strategies for two major health problems by controlling the function of UPS opens up new avenues for innovative approaches and therapeutic interventions.

A Uchl1-Histone2BmCherry:GFP-gpi BAC transgene for imaging neuronal progenitors

Uchl1 encodes the protein gene product 9.5 antigen (PGP9.5) that is a widely used to identify migrating neural progenitors in the PNS, mature neurons of the central and peripheral nervous systems, as well as neuroendocrine cells. To facilitate analysis of developing peripheral neurons, we linked regulatory regions of Uchl1 carried within a 160kb bacterial artificial chromosome (BAC) to the dual fluorescent reporter H2BmCherry:GFP-gpi. The Uchl1-H2BmCherry:GFP-gpi transgene exhibits robust expression and allows clear discrimination of individual cells and cellular processes in cranial ganglia, sympathetic chain, the enteric nervous system (ENS), and autonomic ganglia of the urogenital system. The transgene also labels subsets of cells in endocrine tissues where earlier in situ hybridization (ISH) studies have previously identified expression of this deubiquinating enzyme. The Uchl1-H2BmCherry:GFP-gpi transgene will be a powerful tool for static and live imaging, as well as isolation of viable neural progenitors to investigate processes of autonomic neurogenesis.

eGFP expression under UCHL1 promoter genetically labels corticospinal motor neurons and a subpopulation of degeneration-resistant spinal motor neurons in an ALS mouse model

Understanding mechanisms that lead to selective motor neuron degeneration requires visualization and cellular identification of vulnerable neurons. Here we report generation and characterization of UCHL1-eGFP and hSOD1(G93A)-UeGFP mice, novel reporter lines for cortical and spinal motor neurons. Corticospinal motor neurons (CSMN) and a subset of spinal motor neurons (SMN) are genetically labeled in UCHL1-eGFP mice, which express eGFP under the UCHL1 promoter. eGFP expression is stable and continues through P800 in vivo. Retrograde labeling, molecular marker expression, electrophysiological analysis, and cortical circuit mapping confirmed CSMN identity of eGFP(+) neurons in the motor cortex. Anatomy, molecular marker expression, and electrophysiological analysis revealed that the eGFP expression is restricted to a subset of small-size SMN that are slow-twitch α and γ motor neurons. Crossbreeding of UCHL1-eGFP and hSOD1(G93A) lines generated hSOD1(G93A)-UeGFP mice, which displayed the disease phenotype observed in a hSOD1(G93A) mouse model of ALS. eGFP(+) SMN showed resistance to degeneration in hSOD1(G93A)-UeGFP mice, and their slow-twitch α and γ motor neuron identity was confirmed. In contrast, eGFP(+) neurons in the motor cortex of hSOD1(G93A)-UeGFP mice recapitulated previously reported progressive CSMN loss and apical dendrite degeneration. Our findings using these two novel reporter lines revealed accumulation of autophagosomes along the apical dendrites of vulnerable CSMN at P60, early symptomatic stage, suggesting autophagy as a potential intrinsic mechanism for CSMN apical dendrite degeneration.

PGP 9.5 immunocytochemical staining for pancreatic endocrine tumors

AIMS/HYPOTHESIS

Protein gene product 9.5 (PGP 9.5) is a marker for neuroendocrine cells but has not been used for pancreatic islet cells and pancreatic endocrine tumors (PETs). Antibodies for PGP 9.5 are now commercially available for immunocytochemical study, with which immunostaining may be able to differentiate between benign and malignant PETs.

RESULTS

All 4 kinds of normal islet cells were positively immunostained for PGP 9.5-moderately positive for β-cells and strongly positive for δ-cells, whereas ganglion cells were immunostained more strongly than islet cells. Nine of 12 insulinomas were moderately to strongly positive for PGP 9.5. Two glucagonomas, 3 of 6 pancreatic polypeptidomas (PPomas), 3 of 9 gastrinomas, and 2 of 4 non-functioning PETs were negative for PGP 9.5.

MATERIALS AND METHODS

Thirty-four PETs were immunocytochemically stained for PGP 9.5 using a rabbit polyclonal antibody together with immunostaining for 4 pancreatic hormones, chromogranin A (CgA), and gastrin. PETs consisted of 12 insulinomas, 2 glucagonomas, 1 somatostatinoma (SRIFoma), 6 PPomas, 9 gastrinomas, and 4 non-functioning PETs.

CONCLUSION/INTERPRETATION

PGP 9.5 immunostaining was universally positive for 4 kinds of islet cells and was moderately to strongly positive for 9 of 12 (75%) insulinomas. All 22 non-β-cell PETs were negative or weakly positive for PGP 9.5, and thus negative or weakly positive PGP 9.5 immunostaining may be used as a marker for potential malignancy and poor prognosis for non-β-cell PETs.

Apc deficiency alters pulmonary epithelial cell fate and inhibits Nkx2.1 via triggering TGF-beta signaling

Wnt signaling is critical for cell fate specification and cell differentiation in many organs, but its function in pulmonary neuroendocrine cell (PNEC) differentiation has not been fully addressed. In this study, we examined the role of canonical Wnt signaling by targeting the gene for Adenomatous Polyposis Coli (Apc), which controls Wnt signaling activity via mediating phosphorylation of beta-catenin (Ctnnb). Targeting the Apc gene in lung epithelial progenitors by Nkx2.1-cre stabilized Ctnnb and activated canonical Wnt signaling. Apc deficiency altered lung epithelial cell fate by inhibiting Clara and ciliated cell differentiation and activating Uchl1, a marker of neuroendocrine cells. Similar to PNEC in normal lung, Uchl1(positive) cells were innervated. In mice with targeted inactivation of Ctnnb by Nkx2.1-cre, PNEC differentiation was not interrupted. These indicate that, after lung primordium formation, Wnt signaling is not essential for PNEC differentiation; however, its over-activation promotes PNEC features. Interestingly, Nkx2.1 was extinguished in Apc deficient epithelial progenitors before activation of Uchl1. Examination of Nkx2.1 null lungs suggested that early deletion of Nkx2.1 inhibits PNEC differentiation, while late repression does not. Nkx2.1 was specifically inhibited in Apc deficient lungs but not in Ctnnb gain-of-function lungs indicating a functional difference between Apc deletion and Ctnnb stabilization, both of which activate Wnt signaling. Further analysis revealed that Apc deficiency led to increased TGF-beta signaling, which inhibited Nkx2.1 in cultured lung endodermal explants. In contrast, TGF-beta activity was not increased in Ctnnb gain-of-function lungs. Therefore, our studies revealed an important mechanism involving Apc and TGF-beta signaling in regulating the key transcriptional factor, Nkx2.1, for lung epithelial progenitor cell fate determination.

Nociceptive sensory innervation of the posterior cruciate ligament in osteoarthritic knees

INTRODUCTION

Although the posterior cruciate ligament (PCL) is considered to contain not only proprioceptive but also nociceptive sensory fibers, there is a lack of information about nociceptive sensory innervation of the PCL. We hypothesized that the PCL has constant nociceptive sensory innervation, suggesting the possible source of osteoarthritic (OA) knee pain.

MATERIALS AND METHODS

Innervation of the PCL was examined by immunohistochemistry with particular reference to nociceptive nerve fibers in OA knees. Sensory nerve fibers were semi-quantitatively counted in the PCL of OA knees, comparing with non-OA knees. Protein gene product 9.5 (PGP9.5) as a general neuronal marker and calcitonin gene related peptide (CGRP) as a marker for nociceptive neuron were used.

RESULTS

The PCLs had constant CGRP-immunoreactive (IR) nerve fibers in both OA and non-OA knees. The difference of the CGRP-IR nerve density between groups did not reach a statistical significance (p = 0.062). For PGP9.5-IR nerve fibers, however, the PCLs in OA knees were statistically less innervated than non-OA knees (p = 0.0009).

CONCLUSIONS

Our results showed that, in spite of a significant decrease in total innervation in OA knees, the PCLs have constant nociceptive sensory innervation. Although the relationship between the decrease in total innervations in the PCL and OA pathophysiology is still unclear, the PCL is the possible source of OA knee pain. Our results should be taken into account when examining the pain source of the OA knees and handling the PCL during total knee arthroplasty.

Assessment of the innervation pattern of oral squamous cell carcinoma using neural protein gene product (9.5)-An immunocytochemical study

BACKGROUND

This study was carried out to assess the innervation patterns in oral cancer using the general neuronal marker protein gene product 9.5 (PGP 9.5) and to find an explanation for why oral cancer tends to be painless in the early stages.

MATERIALS AND METHODS

Tumor tissue from 30 unselected patients with oral squamous cell carcinoma was evaluated for this study. PGP 9.5 was used to localize nerve fibers in oral squamous cell carcinoma. An indirect immunofluorescence technique using biotin/FITC streptavidin detection system was used on paraffin wax sections of tumor tissue fixed in neutral buffered formalin.

RESULTS

There was no PGP9.5 immunoreactivity in the normal tissue adjacent to the tumor in 18 cases out of 30 (60%). In 12/30 of oral squamous cell carcinoma, preexisting nerve fibers were detected in tissue stroma adjacent to the cancer tissue. Labeled nerve fibers between tumor cells were detected only in 2 out of the 30 cases.

CONCLUSION

There are no apparent patterns of innervations in the cancer tissues themselves, but there are innervations patterns in the surrounding tissue, which presumably represents preexisting nerves. These results may partly explain why oral cancer tends to be painless in the early stages.

Vibration from a riveting hammer causes severe nerve damage in the rat tail model

INTRODUCTION

Hand-arm vibration syndrome (HAVS) is an occupational neurodegenerative and vasospastic disorder in workers who use powered hand tools. Frequency weighting (ISO 5349) predicts little risk of injury for frequencies >500 HZ. Potentially damaging high frequencies abound in impact tool-generated shock waves.

METHODS

A rat tail impact vibration model was developed to deliver shock-wave vibration from a riveting hammer to simulate bucking bar exposure. Rat tails were vibrated continuously for 12 min. Tail flick withdrawal times were determined for noxious heat. Nerve trunks and skin were processed for light and electron microscopy.

RESULTS

Immediately after vibration, the tails were hyperalgesic and had disrupted myelinated axons, fragmented nerve endings, and mast-cell degranulation. By 4 days, the tails were hypoalgesic; nerve endings were lost in the skin.

CONCLUSIONS

Shock-wave vibration causes severe nerve damage. Frequency weighting seriously underestimates the risk of nerve injury with impact tools.

Porcine UCHL1: genomic organization, chromosome localization and expression analysis

The human UCHL1 gene encodes the ubiquitin C-terminal hydrolase UCHL1, which comprises more than 2% of total brain protein. UCHL1 is a component of the ubiquitin-proteasome system, which degrades overexpressed and damaged proteins. Mutations in the UCHL1 gene are associated with susceptibility to and protection from Parkinson's disease. Here we report cloning, characterization, expression analysis and mapping of porcine UCHL1. The UCHL1 cDNA was amplified by reverse transcriptase polymerase chain reaction (RT-PCR) using oligonucleotide primers derived from in silico sequences. The porcine cDNA codes for a protein of 223 amino acids which shows a very high similarity to human (98%) and to mouse (97%) UCHL1. In addition, the genomic organization of the porcine UCHL1 gene was determined. The porcine UCHL1 gene was mapped to chromosome 8(½p21)-p23. Three SNPs were found in the porcine UCHL1 sequence. Expression analysis by quantitative real time RT-PCR demonstrated that porcine UCHL1 mRNA is differentially expressed in various organs and tissues and similar to its human counterpart. UCHL1 transcript is most abundant in brain tissues and in the spinal cord. The UCHL1 mRNA expression was also investigated in developing porcine embryos. UCHL1 transcript was detected as early as 40 days of gestation. A significant decrease in UCHL1 transcript was detected in basal ganglia from day 60 to day 115 of gestation.

Evidence for neural progenitor cells in the human adult enteric nervous system

Putative neural stem cells have been identified within the enteric nervous system (ENS) of adult rodents and cultured from human myenteric plexus. We conducted studies to identify neural stem cells or progenitor cells within the submucosa of adult human ENS. Jejunum tissue was removed from adult human subjects undergoing gastric bypass surgery. The tissue was immunostained, and confocal images of ganglia in the submucosal plexus were collected to identify protein gene product 9.5 (PGP 9.5) - immunoractive neurons and neuronal progenitor cells that coexpress PGP 9.5 and nestin. In addition to PGP-9.5-positive/nestin-negative neuronal cells within ganglia, we observed two other types of cells: (1) cells in which PGP 9.5 and nestin were co-localized, (2) cells negative for both PGP 9.5 and nestin. These observations suggest that the latter two types of cells are related to a progenitor cell population and are consistent with the concept that the submucosa of human adult ENS contains stem cells capable of maintenance and repair within the peripheral nervous system.

Abnormal development of the enteric nervous system in rat embryos and fetuses with congenital diaphragmatic hernia

BACKGROUND/AIM

Esophageal dilatation, gastroesophageal reflux, and intestinal obstruction have been demonstrated in CDH survivors. Abnormal esophageal and intestinal innervations were recently found in rats and babies with this disease. Our aim was to further characterize these malformations in embryos and fetal rats exposed to nitrofen.

METHODS

Pregnant rats received either 100 mg nitrofen or vehicle on E9.5. Fetuses were recovered at E15, E18, and E21. Sections of esophagus and small bowel were histochemically stained with acetylcholinesterase (AChE) and immunostained for PGP9.5. PGP9.5 gen protein were measured on E21 and PGP9.5 mRNA on E15, E18 and E21. Comparisons between groups were made with non-parametrics tests.

RESULTS

Histochemistry and immunohistochemistry showed deficient innervation in all anatomical areas studied at E15, E18, and E21, and WB confirmed this decrease in E21 fetuses. PGP9.5 messenger was decreased in nitrofen-exposed animals on E18 (esophagus) or E15 (small bowel), and increased on E21 in the esophagus and E18 in small bowel.

CONCLUSIONS

Development of the enteric nervous system of the esophagus, stomach, and small bowel is deficient in rat embryos and fetuses exposed to nitrofen. These anomalies could account in part for the long-term gastrointestinal morbidity observed in CDH survivors.

Human cord blood CD133+ stem cells transplanted to nod-scid mice provide conditions for regeneration of olfactory neuroepithelium after permanent damage induced by dichlobenil

The herbicide dichlobenil selectively causes necrosis of the dorsomedial part of olfactory neuroepithelium (NE) with permanent damage to the underlying mucosa, whereas the lateral part of the olfactory region and the nasal respiratory mucosa remain undamaged. We investigated here whether human umbilical cord blood CD133(+) stem cells (HSC) injected intravenously to nod-scid mice pretreated with dichlobenil may engraft the olfactory mucosa and contribute to the regeneration of the damaged NE. We tested HLA-DQalpha1 DNA and three human microsatellites (Combined DNA Index System) as indicators of engrafted cells, finding polymerase chain reaction evidence of chimaerism in various tissues of the host, including the olfactory mucosa and bulb, at 7 and 31 days following HSC transplantation. Histology, immunohistochemistry, and lectin staining revealed the morphological recovery of the dorsomedial region of the NE in dichlobenil-treated mice that received HSC, contrasting with the lack of regeneration in similarly injured areas as these remained damaged in control nontransplanted mice. FISH analysis, to detect human genomic sequences from different chromosomes, confirmed persistent engraftment of the regenerating olfactory area with chimeric cells. Electro-olfactograms in response to odorants, to test the functionality of the olfactory NE, confirmed the functional damage of the dorsomedial area in dichlobenil-treated mice and the functional recovery of the same area in transplanted mice. These findings support the concept that transplanted HSC migrating to the damaged olfactory area provide conditions facilitating the recovery from olfactory receptor cell loss.

Tracheal innervation is abnormal in rats with experimental congenital diaphragmatic hernia

BACKGROUND

Tracheobronchial motility influences lung development. Lung hypoplasia and lung sequelae accompany congenital diaphragmatic hernia (CDH) in which the vagus nerves and esophageal innervation are abnormal. As the vagus supplies tracheal innervation, this study tested the hypothesis that it might also be abnormal in rats with CDH.

MATERIAL AND METHODS

Intrinsic ganglia were counted and measured in whole mount acetylcholinesterase-stained tracheas from CDH and control E21 fetal rats. The relative surfaces occupied by neural structures were measured in tracheal sections immunostained for p75(NTR) and PGP 9.5. PGP 9.5 protein and mRNA expression were determined. Mann-Whitney tests were used for comparisons between groups using P < .05 as significant.

RESULTS

p75(NTR) staining showed the neural crest origin of tracheal innervation. Scarce neural structures and smaller ganglia were found in CDH fetuses. PGP 9.5 protein expression was decreased in CDH fetuses, whereas PGP 9.5 mRNA levels were increased in comparison with controls.

CONCLUSIONS

Decreased density of neural structures and size of intramural ganglia, reduced expression of neural tissue and PGP 9.5 protein, and increased levels of PGP 9.5 mRNA reveal deficient tracheal innervation in rats with CDH. If similar anomalies exist in the human condition, they could contribute to explaining the pathogenesis of lung hypoplasia and bronchopulmonary sequelae.

PGP 9.5 and Cyclin D1 Coexpression in Cutaneous Squamous Cell Carcinomas

Background: squamous cell carcinoma (SCC) consists of altered keratinocytes, presents variable differentiation, inexorably progresses, and on occasion metastasizes. Objective: to investigate the biological activity of epidermal cells in SCCs by estimating the expression of PGP 9.5 and cyclin D1 using immunohistochemistry. Methods: the sample included 13 well-differentiated cases of cutaneous SCC (grade I), 12 moderately differentiated tumors (grade II), and 7 poorly differentiated lesions (grade III). Four cases belonged to the distinct entity of pseudoadenoid SCC. Results: PGP 9.5 expression was positively correlated with tumor stage ( P < .001) and potential perineural invasion ( P < .001), whereas cyclin D1 expression correlated inversely with the degree of cellular differentiation ( P < .001) and PGP 9.5 immunostaining ( P < .001). Conclusion: PGP 9.5 and cyclin D1 coexpression was closely associated with tumor aggressiveness and can be classified as a marker for predicting the outcome of resection-treated skin cancer patients.

Useful markers for detecting minimal residual disease in cases of neuroblastoma

Neuroblastoma (NB), which is a malignant tumor of young children derived from neural crest cells that occurs in children, exhibits a wide range of clinical behaviors, from spontaneous regression to rapid progression. Advanced NB patients have a poor prognosis, and recently, autologous bone marrow transplantation (BMT) and autologous peripheral blood stem cell transplantation (PBSCT) have been attempted to improve the prognosis of these patients. In this study, we attempted to detect the expression of tyrosine hydroxylase (TH), neuroendocrine protein gene product (PGP) 9.5, ELAVL-4 and GD2 synthetase (GALGT), all of which are highly expressed in NBs, by the reverse transcription-polymerase chain reaction (RT-PCR) technique in order to detect minimal residual disease (MRD) in the bone marrow (BM) and peripheral blood (PB). Analysis of various tumor cell lines (Ewing's sarcoma, hepatoma, leukemias, and breast cancer cell lines in addition to NBs), and human normal samples (BM and PB cells) revealed that TH was the most specific marker for the detection of NB. On the other hand, PGP9.5 was the most sensitive marker, and was detected even when there was only one positive cell per 10(7) negative cells. We concluded that TH is a better marker before the diagnosis of NB while PGP9.5 is a better marker to detect MRD after the diagnosis. Here, we describe our results on useful markers to detect MRD in patients with NB.

Analyzing somatosensory axon projections with the sensory neuron-specific Advillin gene

Peripheral sensory neurons detect diverse physical stimuli and transmit the information into the CNS. At present, the genetic tools for specifically studying the development, plasticity, and regeneration of the sensory axon projections are limited. We found that the gene encoding Advillin, an actin binding protein that belongs to the gelsolin superfamily, is expressed almost exclusively in peripheral sensory neurons. We next generated a line of knock-in mice in which the start codon of the Advillin is replaced by the gene encoding human placenta alkaline phosphatase (Avil-hPLAP mice). In heterozygous Avil-hPLAP mice, sensory axons, the exquisite sensory endings, as well as the fine central axonal collaterals can be clearly visualized with a simple alkaline phosphatase staining. Using this mouse line, we found that the development of peripheral target innervation and sensory ending formation is an ordered process with specific timing depending on sensory modalities. This is also true for the in-growth of central axonal collaterals into the brainstem and the spinal cord. Our results demonstrate that Avil-hPLAP mouse is a valuable tool for specifically studying peripheral sensory neurons. Functionally, we found that the regenerative axon growth of Advillin-null sensory neurons is significantly shortened and that deletion of Advillin reduces the plasticity of whisker-related barrelettes patterns in the hindbrain.

Inflammatory cell accumulation in traumatic neuromas of the human lingual nerve

OBJECTIVE

To quantify the accumulation of inflammatory cells in traumatic neuromas of the human lingual nerve, and to establish any correlation with the patients' reported symptoms of dysaesthesia.

DESIGN

Using fluorescence immunohistochemistry, the extent of any chronic inflammatory infiltrate was quantified in human lingual neuroma specimens removed from 24 patients at the time of microsurgical nerve repair. A pan-leucocyte marker (CD45) and a specific macrophage marker (CD68) were used, and comparisons made between neuromas-in-continuity (NICs) and nerve-end neuromas (NENs) in patients with or without symptoms of dysaesthesia.

RESULTS

CD68 and CD45 labelling was significantly associated with areas of viable nerve tissue in neuromas and the CD68 labelling was significantly higher in NICs than NENs. CD68 labelling density tended to decrease with increasing time after the initial nerve injury, but this correlation was only significant for labelling associated with viable nerve tissue in NENs. No significant difference was found between the level of CD68 or CD45 labelling in patients with or without symptoms of dysaesthesia.

CONCLUSION

This study has demonstrated the presence of inflammatory cells within traumatic neuromas of the human lingual nerve. These cells were found to be closely associated with regions of viable nerve tissue, but there was no correlation with the patients' clinical symptoms.

2-D DIGE as a quantitative tool for investigating the HUPO Brain Proteome Project mouse series

Brain development and aging is a complex process involving proliferation, differentiation and apoptosis. Elucidating proteome changes in these processes can help to understand the mechanisms of brain development and maintenance as well as neurodegenerative diseases. The research reported here is a contribution to the HUPO Brain Proteome Project mouse pilot study. Whole, frozen C57BL/6J mouse brain comprising three different developmental stages (embryonic day 16, postnatal day 7, and postnatal days 54-58) were processed by using 2-D DIGE. A total of 1999 spots were matched between all gels. Of these, 206 spots were differentially expressed between the different stages: 122 spots were highest in intensity in embryonic stage E16, 26 highest in the juvenile group P7 and 58 spots highest in P56, the adult stage. The results show a pattern of temporal expression. Based on the expression patterns we tentatively suggest that proteins involved in the establishment of primary structures in the brain are expressed highest in the embryonic mouse. Proteins involved in the development of the brain are expressed highest in the juvenile phase and proteins that make utilization of the brain possible by delivering energy are expressed highest in the adult mice.

Olfactory epithelia differentially express neuronal markers

All three olfactory epithelia, the olfactory epithelium proper (OE), the septal organ of Masera (SO), and the vomeronasal organ of Jacobson (VNO) originate from the olfactory placode. Here, their diverse neurochemical phenotypes were analyzed using the immunohistochemical expression pattern of different neuronal markers. The olfactory bulb (OB) served as neuronal control. Neuronal Nuclei Marker (NeuN) is neither expressed in sensory neurons in any of the three olfactory epithelia, nor in relay neurons (mitral/tufted cells) of the OB. However, OB interneurons (periglomerular/granule cells) labeled, as did supranuclear structures of VNO supporting cells and VNO glands. Protein Gene Product 9.5 (PGP9.5 = C-terminal ubiquitin hydrolase L1 = UCHL1) expression is exactly the opposite: all olfactory sensory neurons express PGP9.5 as do OB mitral/tufted cells but not interneurons. Neuron Specific Enolase (NSE) expression is highest in the most apically located OE and SO sensory neurons and patchy in VNO. In contrast, the cytoplasm of the most basally located neurons of OE and SO immunoreacted for Growth Associated Protein 43 (GAP-43/B50). In VNO neurons GAP-43 labeling is also nuclear. In the cytoplasm, Olfactory Marker Protein (OMP) is most intensely expressed in SO, followed by OE and least in VNO neurons; further, OMP is also expressed in the nucleus of basally located VNO neurons. OB mitral/tufted cells express OMP at low levels. Neurons closer to respiratory epithelium often expressed a higher level of neuronal markers, suggesting a role of those markers for neuronal protection against take-over. Within the VNO the neurons show clear apical-basal expression diversity, as they do for factors of the signal transduction cascade. Overall, expression patterns of the investigated neuronal markers suggest that OE and SO are more similar to each other than to VNO.

Cardiac sympathetic neuroprotective effect of desipramine in tachycardia-induced cardiomyopathy

Cardiac sympathetic transmitter stores are reduced in the failing heart. In this study, we proposed to investigate whether the reduction of cardiac sympathetic neurotransmitters was associated with increased interstitial norepinephrine (NE) and reactive oxygen species in congestive heart failure (CHF), using a microdialysis technique and salicylate to detect ·OH generation. Rabbits with and without rapid ventricular pacing (340 beats/min) were randomized to receive desipramine (10 mg/day) or placebo for 8 wk. Rapid pacing produced left ventricular dilation and systolic dysfunction. The failing myocardium also showed reduced tissue contents of NE and tyrosine hydroxylase protein and activity. In contrast, myocardial interstitial NE was increased in CHF (0.89 ± 0.11 ng/ml) compared with the sham-operated animals (0.26 ± 0.03 ng/ml). In addition, cardiac oxidative stress was increased in CHF animals as measured by myocardial interstitial ·OH radical, tissue oxidized glutathione, and oxidized mitochondrial DNA. Desipramine treatment produced significant NE uptake inhibition as evidence by an exaggerated pressor response and a greater increase of myocardial interstitial NE in response to intravenous NE infusion but no significant effects on cardiac function or hemodynamics in sham-operated or CHF animals. However, desipramine treatment attenuated the reductions of tissue NE and tyrosine hydroxylase protein and activity in CHF. Desipramine also prevented the reduction of tyrosine hydroxylase produced by NE in PC12 cells. Thus the reduction of cardiac sympathetic neurotransmitters is related to the increased interstitial NE and tissue oxidative stress in CHF. Also, normal neuronal uptake of NE is required for NE or its oxidized metabolites to exert their neurotoxic effects.

Synthesis and characterization of fluorescent ubiquitin derivatives as highly sensitive substrates for the deubiquitinating enzymes UCH-L3 and USP-2

Deubiquitinating enzymes (DUBs) catalyze the removal of attached ubiquitin molecules from amino groups of target proteins. The large family of DUBs plays an important role in the regulation of the intracellular homeostasis of different proteins and influences therefore key events such as cell division, apoptosis, etc. The DUB family members UCH-L3 and USP2 are believed to inhibit the degradation of various tumor-growth-promoting proteins by removing the trigger for degradation. Inhibitors of these enzymes should therefore lead to enhanced degradation of oncoproteins and may thus stop tumor growth. To develop an enzymatic assay for the search of UCH-L3 and USP2 inhibitors, C-terminally labeled ubiquitin substrates were enzymatically synthesized. We have used the ubiquitin-activating enzyme E1 and one of the ubiquitin-conjugating enzymes E2 to attach a fluorescent lysine derivative to the C terminus of ubiquitin. Since only the epsilon-NH(2) group of the lysine derivatives was free and reactive, the conjugates closely mimic the isopeptide bond between the ubiquitin and the lysine side chains of the targeted proteins. Various substrates were synthesized by this approach and characterized enzymatically with the two DUBs. The variant consisting of the fusion protein between the large N-terminal NusA tag and the ubiquitin which was modified with alpha-NH(2)-tetramethylrhodamin-lysine, was found to give the highest dynamic range in a fluorescence polarization readout. Therefore we have chosen this substrate for the development of a miniaturized, fluorescence-polarization-based high-throughput screening assay.

Structural development of PGP9.5-immunopositive myenteric plexus in embryonic rats

To investigate relationships between changes in the 3-dimensional structure of the myenteric plexus and the time at which functional movement of intestine begins in mammalian embryos, whole mounts of embryonic rat intestine were examined under confocal laser scanning microscopy on spacer-equipped glass slides after immunostaining with antiprotein gene product 9.5 antibody. At embryonic day 12.5, very few nerve cells were scattered throughout the small intestine, but no immunostained structures were apparent on the anal side of the large intestine. At embryonic day 13.5, immunostained fibers appeared on the oral side of the large intestine. Nerve cells and associated fiber bundles formed neuronal networks with large meshes in both intestines. Marked increases in number of nerve fibers and decreases in mesh size were seen in the small intestine between embryonic days 13.5 and 15.5. Similar changes were found in the large intestine between embryonic days 13.5 and 16.5. After embryonic day 16.5, nerve cells were arranged parallel to circular muscle fibers, and networks formed by cell fibers elongated until the neonatal period in both intestines. Meconium passed through the large intestine from embryonic day 17.5. Thin fiber bundles extended from the ganglion to the inner side of the myenteric layer, parallel (and occasionally extending) to the circular muscle fibers. Formation of nerve fiber networks and arrangement of nerve cells parallel to circular muscle fibers probably relate to movement coordination for inner circular muscle fibers in the intestinal wall, and development of this neural network may be important for acquiring intestinal movements before birth.

Localization of ubiquitin carboxyl-terminal hydrolase-L1 in cynomolgus monkey placentas

Ubiquitin carboxyl-terminal hydrolase-L1 (UCH-L1) is a restrictedly expressed enzyme in neural and reproductive tissues, and it is considered to have a significant role in reproduction. In the present study, we investigated the localization of UCH-L1 in placenta of cynomolgus monkeys (Macaca fascicularis). UCH-L1 protein was detected in cytotrophoblasts of chorionic plate and villi, and decidual cells of decidua basalis in cynomolgus monkey placenta, and the amount of UCH-L1 protein in whole placenta increased as pregnancy progressed. These results supported that UCH-L1 is necessary for placental and fetal development in primate placenta. This is the first report to demonstrate the presence of UCH-L1 in primate placenta, and the cynomolgus monkey may be a useful model for the study of the functions of the ubiquitin-proteasome system in human pregnancy.

DE NOVO SYNTHESIS OF UBIQUITIN CARBOXYL-TERMINAL HYDROLASE ISOZYME L1 IN ROSTRAL VENTROLATERAL MEDULLA IS CRUCIAL TO SURVIVAL DURING MEVINPHOS INTOXICATION

Ubiquitin carboxyl-terminal hydrolase isozyme L1 (UCH-L1) is a deubiquitinating enzyme that is responsible for making ubiquitin, which is required to target proteins for degradation by the ubiquitin-proteasome pathway in neurons, available. We investigated whether UCH-L1 plays a neuroprotective role at the rostral ventrolateral medulla (RVLM), the origin of sympathetic neurogenic vasomotor tone in the medulla oblongata where the organophosphate insecticide mevinphos (Mev) acts to elicit cardiovascular toxicity. In Sprague-Dawley rats maintained under propofol anesthesia, Mev (960 microg/kg, i.v.) induced a parallel and progressive augmentation in UCH-L1 or ubiquitin expression at the ventrolateral medulla during the course of Mev intoxication. The increase in UCH-L1 level was significantly blunted on pretreatment with bilateral microinjection into the RVLM of a transcription inhibitor, actinomycin D (5 nmol), or a translation inhibitor, cycloheximide (20 nmol). Compared with aCSF or sense oligonucleotide (100 pmol) pretreatment, microinjection of an antisense uch-L1 oligonucleotide (100 pmol) bilaterally into the RVLM significantly increased mortality, reduced the duration of the "pro-life" phase, blunted the increase in ubiquitin expression in ventrolateral medulla, and augmented the induced hypotension in rats that received Mev. These findings suggest that de novo synthesis of UCH-L1, leading to an enhanced disassembly of ubiquitin-protein conjugates in the RVLM, is essential to maintenance of the "pro-life" phase of Mev intoxication via prevention of cardiovascular depression, leading to neuroprotection.

Anatomical and functional evidence for a role of arginine-vasopressin (AVP) in rat olfactory epithelium cells

The olfactory epithelium (OE) is composed of olfactory sensory neurons (OSNs) and sustentacular cells; it lies in the nasal cavity where it is protected by a thin mucus layer. The finely regulated composition of this mucus provides OSN with a suitable ionic environment. To maintain the functional integrity of the epithelium despite permanent physical, chemical and microbial aggressions, both OSNs and surrounding sustentacular cells are continuously renewed from globose basal cells. Moreover, the sense of smell is involved in so numerous behaviours (feeding, reproduction, etc.) that it has to cross-talk with the endocrine and neuroendocrine systems. Thus, besides its sensory function, the olfactory epithelium is thought to undergo a lot of complex regulatory processes. We therefore studied the effects of various neuropeptides on primary cultures of Sprague-Dawley rat olfactory epithelium cells. We found that arginine-vasopressin (AVP) triggered a robust, dose-dependent calcium increase in these cells. The cell response was essentially ascribed to the V1a AVP receptor, whose presence was confirmed by RT-PCR and immunolabelling. In the culture, V1a but not V1b receptors were present, mainly localized in neurons. In the epithelium, both subtypes were found differentially distributed. V1a-R were localized mainly in globose basal cells and at the apical side of the epithelium, in the area of the dendritic knobs of OSNs. V1b-R were strongly associated with Bowman's gland cells and globose basal cells. These localizations suggested potential multifaceted roles of a hormone, AVP, in the olfactory epithelium.

JAB1 enhances HAND2 transcriptional activity by regulating HAND2 DNA binding

HAND2 (also known as dHAND) is a basic helix-loop-helix (bHLH) transcription factor essential for development of the heart, limbs, and neural crest-derived lineages. HAND2 expression is observed in a number of tissues derived from the neural crest, including components of the peripheral nervous system, where it has been shown to regulate sympathetic nervous system development. Here we show that HAND2 is expressed in both the sympathetic and the parasympathetic divisions of the autonomic nervous system (ANS). How HAND2 functions during development of these neuronal lineages is uncertain. An important mechanism involved in HAND2's function is its interactions with other proteins. To understand better the molecular interactions regulating HAND2 during ANS development, we employed a yeast two-hybrid screen to identify HAND2-interacting proteins. One protein identified in this screen, Jun activation domain-binding protein (JAB1), is involved in numerous cell processes, including regulation of transcription and protein turnover. We show that JAB1 binds directly to the HLH domain of HAND2 and increases HAND2 transcription-stimulating activity. However, JAB1 does not contain a transcriptional activation domain, nor does it recruit an activation domain to HAND2. Our data indicate that JAB1 augments HAND2 transcriptional activity by enhancing HAND2 DNA binding. We further show that enhanced HAND2 DNA binding is mediated through the HLH domain and not through the DNA binding domain. These results show that JAB1 regulates the transcriptional activity of HAND2 in a unique manner that may account, in part, for the apparent ability of this bHLH factor to regulate gene expression through numerous mechanisms.

PGP9.5 mRNA could contribute to the molecular-based diagnosis of medullary thyroid carcinoma

The protein gene product 9.5 (PGP9.5) is a ubiquitin hydrolase that is widely expressed in neuronal tissues at all stages of neuronal differentiation and is a known neuroendocrine marker. Medullary thyroid carcinoma (MTC) arises from parafollicular cells and is reported to overexpress several mRNAs such as RET, calcitonin, and CEA. These markers are thought to be useful in determining a molecular-based diagnosis of MTC. We examined the expression levels of PGP9.5 mRNA in 80 thyroid tissues using real-time quantitative reverse transcription (RT-PCR) and found that PGP9.5 mRNA was overexpressed in all 11 MTCs examined, both hereditary and sporadic, but not in other histological tumour types. Furthermore, by RT-PCR, PGP9.5 mRNA was detected only in aspirates from three medullary carcinomas, and not in aspirates from other tumour types. These results demonstrate that, in addition to the expression of RET, calcitonin and CEA, PGP9.5 mRNA expression may contribute to the molecular-based diagnosis of MTCs.

Stimulation of the murine Uchl1 gene promoter by the B-Myb transcription factor

It has been reported that human lung cancers frequently overexpress both the ubiquitous cell cycle transcription factor B-myb and the ubiquitin carboxyterminal hydrolase UCHL1, an enzyme whose expression is normally limited to neurons and neuroendocrine cells in the lung. A possible explanation for the co-expression of these markers is that Uchl1 is subject to transcriptional regulation by B-Myb, and in tumors the ectopic expression of UCHL1 is a direct consequence of B-Myb overexpression. We have tested this hypothesis in the mouse model system by cloning the murine Uchl1 promoter and analyzing its regulation by murine B-Myb. Expression of a luciferase reporter gene driven by the Uchl1 promoter was induced by cotransfected B-Myb, but induction was not dependent on the presence of a myb consensus binding site identified in the promoter region. B-Myb induction was dependent on the context of the Uchl1 TATA box, as has been reported for other genes. Transgenic mice expressing a truncated, constitutively active form of B-Myb in the lung epithelium showed elevated expression of UCHL1 protein. We conclude that B-Myb can stimulate expression of the Uchl1 both in cultured cells and in vivo.