Neural Cell Adhesion Molecule Immunoreactivity Research Articles

The expression of neural cell adhesion molecule and the microenvironment of pituitary neuroendocrine tumours.

The neural cell adhesion molecule (NCAM) has previously been studied in pituitary neuroendocrine tumours (PitNETs), but its role in tumour biology and aggressiveness remains controversial, and its relationship with the tumour microenvironment remains unknown. We aimed to characterise NCAM expression in PitNETs, to correlate this with clinico-pathological features, and to assess the role of various microenvironment components on NCAM expression. NCAM and immune cells were investigated by immunohistochemistry in 16human non-functioning-PitNETs (NF-PitNETs) and eight somatotrophinomas, including macrophages (CD68, CD163, HLA-DR), cytotoxic (CD8) and T helper (CD4) lymphocytes, regulatory T cells (FOXP3), B cells (CD20), and neutrophils (neutrophil elastase). Five normal pituitaries were included for comparison. The cytokine secretome from these PitNETs and from PitNET-derived tumour-associated fibroblasts (TAFs) were assessed on culture supernatants using a multiplex immunoassay panel. There were no significant NCAM expression differences between PitNETs and normal pituitary, and no difference between types of pituitary tumours (NF-PitNETs vs. somatotrophinomas). There was no association between NCAM expression and different clinico-pathological features, including cavernous sinus invasion and Ki-67, nor with serum hormone levels. NCAM immunoreactivity correlated negatively with PitNET-derived CXCL10 (rho=-0.417; p=.042) and CX3CL1 (rho=-0.423; p=.040) levels. NCAM immunoreactivity was negatively correlated with TAF-derived fibroblast growth factor (FGF)-2 (rho=-0.632; p=.009), but not with other TAF-derived cytokines. Within the PitNET cohort, there were no correlations between NCAM immunoreactivity and immune infiltrates or ratios, although, within NF-PitNETs, NCAM expression was higher in tumours with more FOXP3+ cells. NCAM expression does not differ between PitNETs and normal pituitary, and does not appear to relate to tumour invasiveness or proliferation. However, our data suggest a possible role for cytokines in the modulation of NCAM expression in PitNETs, particularly CXCL10, CX3CL1 and FGF-2, but not for immune cell infiltrates.

Caudal Appendage Derived from a Vestigial Remnant of the Tailgut

The presence of smooth muscle at the basal portion of a caudal appendage is very rare. We report a 3-month-old girl in which a caudal appendage is associated with smooth muscle bundles at the perianal region. Immunohistochemistry was performed for NCAM (neural cell adhesion molecule) to identify smooth muscle. NCAM immunoreactivity was observed within the presumptive circular and/or longitudinal muscle layers of the muscularis propria. NCAM is expressed by smooth muscle during the early stages of human embryonic gut development, suggesting that the caudal appendage in the present case may be derived from a tailgut remnant.

Neuronal immaturity in normoganglionic colon from cases of Hirschsprung disease, anorectal malformation, and idiopathic constipation

Aim Immaturity of neurons in normoganglionic colon in Hirschsprung disease (HD), anorectal malformation (AM), idiopathic constipation (IC), and normal controls (C) was assessed using polysialyated neural cell adhesion molecule. Methods Polysialyated neural cell adhesion molecule immunoreactivity in 3 sections of normoganglionic colon from HD (n = 48), AM (n = 25), IC (n = 36), and C (n = 18) were scored semiquantitatively according to age; 1 day to 11 months (G1), 1 to 4 years (G2), and 5 years and older (G3). Results Neurons in all specimens appeared mature irrespective of age on hematoxylin-eosin stain. Polysialyated neural cell adhesion molecule was positive (immaturity) in all specimens during G1 (1.34 in HD, 1.60 in AM, 0.89 in IC, and 1.59 in C) and decreased significantly with age in C (0.34* for G2, 0.25* for G3; * P < .01), decreased after 4 years old in IC (0.93 for G2, 0.10 # for G3; # P < .05), decreased gradually in AM (1.10 for G2, 0.75 § for G3; § P < .05), but remained strongly positive in HD (1.34 for G1, 1.26 for G2, and 1.21 for G3; P = not significant), which after 4 years was significantly higher than C ( P < .05). Conclusion Postoperative colonic dysmotility may be because of persistence of immature neurons in HD and impaired maturation of neurons in AM and IC.

Synaptophysin immunoreactivity in adrenocortical adenomas: a correlation between synaptophysin and CYP17A1 expression

The adrenal cortex is not considered to be an intrinsic part of the diffuse neuroendocrine system, but adrenocortical neoplasms possess neuroendocrine properties. In this study, we examined synaptophysin (SYP) and neural cell adhesion molecule (NCAM) expression in adrenocortical adenomas in relation to adrenal function. Immunohistochemical analysis showed that 50.7 and 98.6% of the cortical adenomas showed SYP and NCAM immunoreactivities respectively. There was no apparent difference in NCAM immunoreactivity among the adenomas. However, the immunostaining for SYP was significantly stronger in cortisol-producing adenomas (CPA) than in aldosterone-producing adenomas (APA), nonfunctioning adenomas (NFA), showing no clinical or endocrinological abnormality, or adenomas associated with preclinical Cushing's syndrome (preCS). Western blotting and real-time PCR demonstrated that the expression level of SYP protein and mRNA was significantly higher in CPA than in APA or NFA. Additionally, the SYP mRNA level showed a positive correlation with CYP17A1 mRNA. In addition to the plasma membrane, mitochondria, and smooth endoplasmic reticulum, SYP immunoreactivity was detected in the Golgi area, which is known to be involved in the regulation of mitochondrial cholesterol and the transport of steroid intermediates. It was unexpected that the ratio of positive cells for SYP in preCS was less than that in APA and NFA. However, further examination is required, because the number of preCS cases we investigated was very small. We propose that SYP expression in adrenocortical cells may be involved in some aspect of adrenal function such as transport or secretion of glucocorticoids.

Characterization of the subventricular zone neurogenic response to rat malignant brain tumors

The subventricular zone (SVZ) is one of the neurogenic regions of the adult brain. We characterized the neurogenic response of the SVZ to the growth of brain tumors in the rat striatum. Abundant nestin positive cells, most likely representing reactive astrocytes, were found surrounding the tumor. However, we observed no substantial migration of nestin positive cells from the SVZ toward the tumor. Tumor growth resulted in decreased numbers of bromodeoxyuridine positive and Ki-67 positive proliferating cells and a concomitant increase in doublecortin and polysialylated neural cell adhesion molecule immunoreactivity within the SVZ. Neuroblasts were observed in high numbers in the area between the SVZ and the tumor, most likely pointing to the SVZ as the principal source of these cells. Neuroblasts located between the SVZ and the tumor expressed the transcription factor Pbx, a marker for immature striatal neurons. However, no evidence of neuroblast differentiation into fully mature neurons was found. This study thus demonstrates increased neuroblast immunoreactivity within the SVZ ipsilateral to a brain tumor in the striatum. SVZ-derived neuroblasts attracted by the tumor adopt an immature striatal phenotype indicating a region specific reparative mechanism in response to a malignant tumor.

Take two NSAIDs and call on your satellite cells in the morning

it is generally agreed that successful skeletal muscle regeneration following intense exercise or injury is facilitated by the protein synthesis machinery and the recruitment of myogenic stem (satellite) cells. Upstream activation of these processes, however, is poorly understood. A growing body of

Notch-1 regulates pulmonary neuroendocrine cell differentiation in cell lines and in transgenic mice

The notch gene family encodes transmembrane receptors that regulate cell differentiation by interacting with surface ligands on adjacent cells. Previously, we demonstrated that tumor necrosis factor-alpha (TNF) induces neuroendocrine (NE) cell differentiation in H82, but not H526, undifferentiated small cell lung carcinoma lines. We now test the hypothesis that TNF mediates NE cell differentiation in part by altering Notch gene expression. First, using RT-PCR, we determined that TNF treatment of H82, but not H526, transiently decreases notch-1 mRNA in parallel with induction of gene expression for the NE-specific marker DOPA decarboxylase (DDC). Second, we treated H82 and H526 with notch-1 antisense vs. sense oligodeoxynucleotides. Using quantitative RT-PCR and Western analyses we demonstrate that DDC mRNA and protein are increased in H82 by notch-1 antisense, whereas notch-1 mRNA and activated Notch-1 protein are decreased. mRNA for Hes1, a transcription factor downstream from activated Notch, is also decreased by Notch-1 antisense in H82 but not H526. After 7 days of Notch-1 antisense treatment, neural cell adhesion molecule (NCAM) immunoreactivity is induced in H82 but not H526. Third, we generated transgenic mice bearing notch-1 driven by the neural/NE-specific calcitonin promoter, which express activated Notch-1 in developing lung epithelium. Newborn NotchCal mouse lungs have high levels of hes1 mRNA, reflecting increased activated Notch, compared with wild-type. NotchCal lungs have decreased CGRP-positive NE cells, decreased protein gene product 9.5 (PGP9.5)-positive NE cells, and decreased gastrin-releasing peptide (GRP), CGRP, and DDC mRNA levels compared with normal littermates. Cumulatively, these observations provide further support for a role for Notch-1 signaling in regulating pulmonary NE cell differentiation.

The effect of β-bungarotoxin, or geniculate ganglion lesion on taste bud development in the chick embryo

Chick taste bud (gemmal) primordia normally appear on embryonic day (E) 16 and incipient immature, spherical-shaped buds at E17. In ovo injection of beta-bungarotoxin at E12 resulted in a complete absence of taste buds in lower beak and palatal epithelium at developmental ages E17 and E21. However, putative gemmal primordia (solitary clear cells; small, cell groupings) remained, lying adjacent to salivary gland duct openings as seen in normal chick gemmal development. Oral epithelium was immunonegative to neural cell adhesion molecule (NCAM) suggesting gemmal primordia are nerve-independent. Some NCAM immunoreactivity was evident in autonomic ganglion-like cells and nerve fibers in connective tissue. After unilateral geniculate ganglion/otocyst excision on E2.5, at developmental ages E18 and posthatching day 1, approximately 12% of surviving ipsilateral geniculate ganglion cells sustained approximately 54% of the unoperated gemmal counts. After E18, proportional stages of differentiation in surviving developing buds probably reflect their degree of innervation, as well as rate of differentiation. Irrespective of the degree of geniculate ganglion damage, the proportion of surviving buds can be sustained at the same differentiated bud stage as on the unoperated side, or may differentiate to a later bud stage, consistent with the thesis that bud maturation, maintenance, and survival are nerve-dependent.

Satellite Cell Activation in Response to 16 Weeks Resistance Loading in Young and Older Adults

Satellite cells are widely considered integral to the mechanisms of load-induced muscle growth/regeneration. However, differential responses of mitogenic/myogenic factors to resistance loading (RL) suggest load mediated satellite cell activation is influenced by age and/or gender. PURPOSE: To directly quantify the number of satellite cells in situ to determine if differences exist by age, gender, or training state (pre-/post 16-wk RL). METHODS: Twelve young (25.0 ± 1 yr, 6 men, YM; 6 women, YF) and 11 older (63.1 ± 1 yr, 6 men, OM; 5 women, OF) adults trained knee extensors by leg press, knee extension, and squat 3 d/wk, 3 sets x 8–12 repetitions, with training loads of 70–80% one-repetition maximum. At baseline and after 16 wk RL, a needle biopsy was taken from m. vastus lateralis. Satellite cells were identified by neural cell adhesion molecule immunoreactivity (NCAM CD-56). Nuclei were counterstained with Mayer's hematoxylin. Satellite cells were denned as nuclei stained brown or with a brown rim localized to the muscle fiber membrane. Total number of nuclei, satellite cells per 100 fibers (SC/100), myonuclei per fiber, mean myofiber area (MFA), and myonuclear domain (myofiber area per nucleus) were quantified. RESULTS: Myofiber hypertrophy based on MFA occurred in YM only (1693 μn2, P<0.05) with no other group showing significant growth. SC/100 did not differ between groups at baseline (YF, 8.7; YM, 12.9; OF, 11.8; OM, 13.9). An overall training effect for SC/100 (28% increase, P<0.05) was driven primarily by YM (59% increase, P<0.05). An age x training interaction (P<0.05) for myonuclei per fiber was driven by YM (+28%) combined with declining trends in older adults (−6%). Pre-training, myonuclear domain was greatest in YM (2002 μm2) and lower in women and older adults (P<0.05), with the smallest domain among OF (1389 μm2). YM were the only age-gender group to maintain myonuclear domain with training (post: 2083 μm2). The other groups began training with a myonuclear domain below a theoretical ceiling (approximately 2000 μm2) and the domain tended to expand with training (main training effect, P<0.01; YF, 17%; OF, 31%; OM, 15%) coincident with subtle trends toward hypertrophy. CONCLUSIONS: After 16 wk RL, some hypertrophy occurs without the fusion of new nuclei. This initial hypertrophy is halted once a ceiling size is reached for myonuclear domain with further hypertrophy requiring the recruitment of additional nuclei. Young men were the only age-gender group to maintain the myonuclear domain ceiling at baseline and add new nuclei in order to maintain the myonuclear domain during load-mediated hypertrophy. Funded by NIAR01 AG17896.

Immunolocalization of SNARE proteins in both type II and type III cells of rat taste buds

Double immunohistochemistry of soluble N-ethylmaleimide-sensitive fusion protein attachment protein receptor (SNARE) proteins [synaptosomal-associated protein of 25 kDa (SNAP-25), syntaxin and vesicle-associated protein-2 (VAMP-2)], and specific cell markers of taste buds cells [alpha-gustducin and phospholipase Cbeta2 (PLCbeta2) for type II cells; neural cell adhesion molecule (NCAM) for type III cells] was applied to gustatory epithelia of the rat circumvallate papillae. All three SNARE proteins were present in some elongated taste buds cells as well as intra-, peri- and subgemmal nerve fibers. Double immunohisotochemistry revealed that nearly all alpha-gustducin and PLCbeta2 immunoreactive cells expressed SNAP-25, syntaxin, and VAMP-2. A majority of NCAM immunoreactive cells showed immunoreactivity for these SNARE proteins. These results indicate that these synapse-associated proteins (SNAP-25, syntaxin and VAMP-2) are present in both type II cells and type III cells. Moreover, more than 50% of intragemmal cells containing SNARE proteins showed immunoreactivities for alpha-gustducin, PLCbeta2, and NCAM, suggesting the possible presence of transitional cells having histochemical properties of both type II and type III cells.

Complete innervation profile of whole bowel resected at pull-through for Hirschsprung’s disease. Unexpected findings

We used Acetylcholinesterase (AchE) staining and neural cell adhesion molecule (NCAM) immunoreactivity to examine such resected lengths to determine the complete innervation profile of resected bowel in Hirschsprung's disease (HD). Resected specimens of colon obtained at pull-through surgery from 15 patients with HD [short type (S-type: n=5), recto-sigmoid type (RS-type: n=5), long type (L-type: n=5)] were sectioned at 1.5 cm intervals and stained conventionally with AchE histochemistry and NCAM immunohistochemistry. The number of positive nerve fibers (PNFs) in the lamina propria and smooth muscle layers was assessed on a scale of 0 to 3 where 0 meant no PNF and 3 meant many PNFs. The three types of HD had different AchE and NCAM innervation profiles, especially the L-type. There were also different AchE and NCAM innervation patterns seen within the same aganglionic or transitional segments of bowel depending on the site of sampling. The mean proportion of transitional segment in resected specimens from RS-type HD was significantly larger than that of S-type HD (P<0.001) although the proportion of aganglionic segments from S- and RS-type HD were almost the same. Our results suggest that the etiology of L-type HD may be different from the etiology of S- and RS-type HD because of different innervation profiles. Because segments of the excised bowel would appear to have different innervation patterns depending on whether the specimen is sampled proximally or distally, it is important to record the exact site of sampling to allow valid comparisons between types of HD to be made.

A Guide to Assessing Damage Response Pathways of the Hair Follicle: Lessons From Cyclophosphamide-Induced Alopecia in Mice

After chemical, biological, or physical damage, growing (i.e. anagen) hair follicles develop abnormalities that are collectively called hair follicle dystrophy. Comparatively lower follicular damage induces the "dystrophic anagen" response pathway (=prolonged, dystrophic anagen, followed by severely retarded follicular recovery). More severe follicular damage induces the dystrophic catagen pathway (=immediate anagen termination, followed by a dystrophic, abnormally shortened telogen and maximally fast follicular recovery). In order to recognize these distinct damage response strategies of the hair follicle in a clinical or histopathological context, we have used the well-established C57BL/6J mouse model of cyclophosphamide-induced alopecia to define pragmatic classification criteria for hair follicle dystrophy (e.g., structure and pigmentation of the hair shaft, location, and volume of ectopic melanin granules, distension of follicular canal, number of TdT-mediated dUTP nick end labeling positive keratinocytes in the hair bulb; neural cell-adhesion molecule immunoreactivity and alkaline phosphatase activity as markers for the level of damage to the follicular papilla). These classification criteria for hair follicle dystrophy are useful not only in chemotherapy-induced alopecia models, but also in the screening of drug-treated or mutant mice in a highly standardized, accurate, sensitive, reproducible, easily applicable, and quantifiable manner.

Temporal changes in NCAM immunoreactivity during taste cell differentiation and cell lineage relationships in taste buds

Neural cell adhesion molecule (NCAM) is a type III cell marker in the taste buds. In order to clarify the cell type of Mash1-expressing cells in taste buds, expression of NCAM was examined in Mash1-expressing taste cells of adult mice in comparison with gustducin- and T1r3-expressing cells, using a combination of NCAM immunohistochemistry and in situ hybridization. About 98% of Mash1-expressing cells were NCAM immunopositive (IP), suggesting that Mash1-expressing cells should be categorized as type III cells. Unexpectedly, small subsets of gustducin- and T1r3-expressing cells were also found to be NCAM-IP, contradicting previous immunohistochemical studies in rats, in which gustducin-IP cells were observed specifically in type II cells, which do not have NCAM immunoreactivity. Examinations of developing taste buds showed temporal changes in the ratio of NCAM-IP cells in gustducin- and T1r3-expressing cells; the ratio of NCAM-IP cells in these gene-expressing cells were approximately 90% at 0.5 days after birth and decreased markedly during development. In contrast, the majority of Mash1-expressing cells showed constant NCAM immunoreactivity throughout development. In addition, BrdU-labeling experiments showed that the differentiation of Mash1-expressing cells precedes those of gustducin- and T1r3-expressing cells in taste buds of adult mice. These results suggest that T1r3- and gustducin-expressing cells are NCAM-IP at the beginning of cell differentiation, and that NCAM immunoreactivity in gustducin- and T1r3-expressing cells might remain from the previous developmental stage expressing Mash1.

Overexpression of neural cell adhesion molecule (NCAM) antigens on intestinal smooth muscle in hypoganglionosis: is hypoganglionosis a disorder of the neuromuscular junction?: H. Kobayashi, Z. Li, A. Yamataka, et al. Pediatr Surg Int 19:190–193, (May), 2003

Hypoganglionosis (HYP) is a rare condition with a deficiency of nerve cells in the myenteric plexus and a very low level of AchE activity. Because the etiology and pathogenesis is still unknown, the authors looked for anomalies in the field of neuromuscular junctions (NMJ). These junctions are essential for a normal bowel motility. To evaluate NMJ, good markers are synaptophysin (SY), present in neuronal synaptic vesicle membranes and responsible for neurotransmission, and NCAM, which is important for the initial nerve/muscle intercellular adhesion during development and for interaction during synaptogenesis. In 3 boys with HYP, full-thickness biopsy segments were taken from all intestinal segments at the age of 1 to 2 weeks of life. All 3 died within 4 to 7 months. The histologic results were compared with 4 autopsied neonates serving as control. In the normal specimens, NCAM and SY immunoreactivity was strong in both plexus. NCAM- and SY-positive NMJ were identified as moderate in nerve fibers within lamina propria and muscularis mucosae, and many NMJs were associated with nerve fibers in the circular and longitudinal muscle layers. The smooth muscle cells of muscularis mucosae and the inner border of circular muscle layer were negative. In HYP, the plexus showed the same strong immunoreactivity as normal tissue but a lack of expression of NCAM- or SY-positive NMJ was found in all layers. A marked increase of NCAM and SY activity was found in the smooth muscle cells of muscularis mucosae and of the inner border of circular muscle layer. Therefore, in HYP immunoreactivity was irregular in smooth muscle cells but lacking in nerves and NMJs. NCAM is expressed by neuroectodermal tissue and is a marker of mature neural tissue. The lack of marked NMJ together with nerve fibers in the HYP smooth intestinal muscle layers show the absence of neural tissue in these area. The present ganglia stain positively; therefore, the ganglion must be mature, even supported by SY staining. The fact, that NCAM is elevated in special layers of smooth muscle cells and in the NMJ associated with muscle cells, can be explained by disorder of the innervation. The depletion of nerve fibers in the NMJ in HYP suggests a disruption in the contact between nerve and muscle cells. Ganglia that are present in HYP appear to be mature, but neurotransmitter flow from neuron to muscle may be disturbed because contacts between muscle and nerve are disrupted, leading to an accumulation of NCAM in muscle cells and resulting in a disturbance of motility.

Localization of neural cell adhesion molecule and pan-cadherin immunoreactivity in intrauterine growth-retarded newborn rat kidneys.

To examine the expression and distribution pattern of neural cell adhesion molecule (N-CAM) and pan-cadherin immunoreactivity in intrauterine growth retardation (IUGR) newborn kidneys, we used a rat model of maternal protein restriction throughout pregnancy. Weak or moderate immunoreactivity for N-CAM and pan-cadherin was seen in some proximal tubules, in the thick segments of Henle, and in the collecting tubules of the control sections. However, the number of tubules expressing N-CAM and pan-cadherin was increased in the IUGR group compared with the control group. Increased density of N-CAM and pan-cadherin immunoreactivity was observed mostly in the proximal tubules, in the thick segments of Henle, and in the collecting tubules of IUGR newborn rat kidneys. Furthermore, N-CAM and pan-cadherin immunoreactivity was present in the thin limb of Henle in the IUGR group, whereas it was absent in the control group. Glomeruli were negative in both groups except for some glomeruli that showed very weak N-CAM staining in the IUGR group. Thus it was demonstrated for the first time that IUGR newborn rat kidneys express N-CAM and cadherin adhesion molecules at specific sites of the nephron.

Temporal and spacial changes of highly polysialylated neural cell adhesion molecule immunoreactivity in amygdala kindling development

To investigate the migration of neural stem cells as well as neural plastic changes in epileptic brain, spaciotemporal expression of immunoreactive highly polysialylated neural cell adhesion molecule (PSA– NCAM) was examined in amygdala kindling development of rat. The neural migration and synaptic remodeling detected with PSA–NCAM staining occurred in dentate gyrus of hippocampus, subventricular zone and pyriform cortex with amygdaloid kindling in generalized seizure but not in partial seizure. Although PSA–NCAM positive dendrite in dentate gyrus was minimally found in the control brain, it extended slightly in animals with partial seizure, and greatly toward the molecular layer with generalized seizure. Thus, the migration of neural stem cells as well as neural plastic changes were spacially and temporally different between brain regions depending on different kindling stages. These changes may mainly contribute to the reorganization of neural network in epileptic brain.

Localization of neural cell adhesion molecule (N-CAM) immunoreactivity in adult rat tissues

Neural cell adhesion molecule (N-CAM) mediates homophilic adhesion between cells and heterophilic adhesion between cells and extracellular matrix in a Ca2+-independent manner. N-CAM is widely expressed during development and plays a crucial role in cell division, migration, and differentiation, but its expression is restricted in adults. The distribution of N-CAM immunoreactivity in adult rat tissues was investigated in the present study. N-CAM immunoreactivity was present in the nervous system in the molecular layer of the cerebellum, ependymal cells surrounding the central canal, axons of the white matter, and in Lamina X of the gray matter of the spinal cord. N-CAM immunoreactivity also was found in autonomic nerves. In the digestive system, N-CAM immunoreactivity was found in the stratified squamous epithelium and nerve plexus of the esophagus, glandular cells of the stomach and pylorus, lamina propria, and epithelium of the villi of the duodenum, jejunum, and ileum. N-CAM immunoreactivity was demonstrated in the secretory cells of the adenohypophysis, islets of Langerhans, and acinar cells of the exocrine pancreas. Alveolar cells of the lung were also N-CAM immunoreactive. In the urinary system, N-CAM immunoreactivity was seen in the proximal convoluted tubules of the kidney. In the male reproductive system, N-CAM immunoreactivity was demonstrated in the nerve plexus around the urethral epithelium and in the nerve fibers around the smooth muscle cells of the corpus cavernosum penis. In the visual system, N-CAM immunoreactivity was seen in the epithelial cells of the corpus ciliaris. Cornea and lens epithelium also showed positive immunoreactivity. Our results suggest that cells in many tissues and organs of the adult rat synthesize N-CAM.

Expression of neural cell adhesion molecule (NCAM) in the peripheral nerve fibers demonstrated by post-embedding immunogold method on ultrathin sections: A preliminary study

The neural cell adhesion molecule, NCAM, is thought to be necessary for the interaction between neurons, axons and glial cells, axons and target structures, and for myelination. The NCAM localization in the peripheral nerves has been less well studied. The data have shown significant differences. In this study, the distribution of the NCAM immunoreactivity in the sciatic nerves of 10- and 15-day-old Wistar rats was examined on ultrathin sections by the immunogold postembedding method. The sections were immunotested with a polyclonal antibody (Santa Cruz Biotechnology) that recognizes rat NCAM. The antibody was visualized with donkey anti-goat IgG, conjugated to 6 nm colloidal gold. NCAM immuno-like activity was found on axoplasmic profiles of myelinated and nonmyelinated axons, at non-assembled myelin lamellae, and at axo-glial junctions of the paranodes. The compact myelin and the Schwann cell cytoplasm were immunonegative. The presence of some NCAM immunoactivity on the level of the noncompact myelin membranes, deprived of the major myelin protein Po, might be associated with the mechanism of their maintenance.

Localization of neural cell adhesion molecule (N-CAM) immunoreactivity in adult rat tissues

Neural cell adhesion molecule (N-CAM) mediates homophilic adhesion between cells and heterophilic adhesion between cells and extracellular matrix in a Ca2+-independent manner. N-CAM is widely expressed during development and plays a crucial role in cell division, migration, and differentiation, but its expression is restricted in adults. The distribution of N-CAM immunoreactivity in adult rat tissues was investigated in the present study. N-CAM immunoreactivity was present in the nervous system in the molecular layer of the cerebellum, ependymal cells surrounding the central canal, axons of the white matter, and in Lamina X of the gray matter of the spinal cord. N-CAM immunoreactivity also was found in autonomic nerves. In the digestive system, N-CAM immunoreactivity was found in the stratified squamous epithelium and nerve plexus of the esophagus, glandular cells of the stomach and pylorus, lamina propria, and epithelium of the villi of the duodenum, jejunum, and ileum. N-CAM immunoreactivity was demonstrated in the secretory cells of the adenohypophysis, islets of Langerhans, and acinar cells of the exocrine pancreas. Alveolar cells of the lung were also N-CAM immunoreactive. In the urinary system, N-CAM immunoreactivity was seen in the proximal convoluted tubules of the kidney. In the male reproductive system, N-CAM immunoreactivity was demonstrated in the nerve plexus around the urethral epithelium and in the nerve fibers around the smooth muscle cells of the corpus cavernosum penis. In the visual system, N-CAM immunoreactivity was seen in the epithelial cells of the corpus ciliaris. Cornea and lens epithelium also showed positive immunoreactivity. Our results suggest that cells in many tissues and organs of the adult rat synthesize N-CAM.

Expression of neural cell adhesion molecule in human liver development and in congenital and acquired liver diseases.

In the liver, neural cell adhesion molecule (NCAM) is a marker of immature cells committed to the biliary lineage and is expressed by reactive bile ductules in human liver diseases. We investigated the possible role of NCAM in the development of intrahepatic bile ducts and aimed at determining whether immature biliary cells can contribute to the repair of damaged bile ducts in chronic liver diseases. Therefore, we performed immunohistochemistry for NCAM and bile duct cell markers cytokeratin 7 and cytokeratin 19 on frozen sections of 85 liver specimens taken from 14 fetuses, 10 donor livers, 18 patients with congenital liver diseases characterized by ductal plate malformations (DPMs), and 43 cirrhotic explant livers. Duplicated ductal plates and incorporating bile ducts during development showed a patchy immunoreactivity for NCAM, while DPMs were continuously positive for NCAM. Bile ducts showing complete or patchy immunoreactivity for NCAM were found in cirrhotic livers, with higher frequency in biliary than in posthepatitic cirrhosis. Our results suggest that NCAM may have a function in the development of the intrahepatic bile ducts and that NCAM-positive immature biliary cells can contribute to the repair of damaged bile ducts in chronic liver diseases.