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PubMed2006

Keratin 20 serine 13 phosphorylation is a stress and intestinal goblet cell marker.

Keratin polypeptide 20 (K20) is an intermediate filament protein with preferential expression in epithelia of the stomach, intestine, uterus, and bladder and in Merkel cells of the skin. K20 expression is used as a marker to distinguish metastatic tumor origin, but nothing is known regarding its regulation and function. We studied K20 phosphorylation as a first step toward understanding its physiologic role. K20 phosphorylation occurs preferentially on serine, with a high stoichiometry as compared with keratin polypeptides 18 and 19. Mass spectrometry analysis predicted that either K20 Ser(13) or Ser(14) was a likely phosphorylation site, and Ser(13) was confirmed as the phospho-moiety using mutation and transfection analysis and generation of an anti-K20-phospho-Ser(13) antibody. K20 Ser(13) phosphorylation increases after protein kinase C activation, and Ser(13)-to-Ala mutation interferes with keratin filament reorganization in transfected cells. In physiological contexts, K20 degradation and associated Ser(13) hyperphosphorylation occur during apoptosis, and chemically induced mouse colitis also promotes Ser(13) phosphorylation. Among mouse small intestinal enterocytes, K20 Ser(13) is preferentially phosphorylated in goblet cells and undergoes dramatic hyperphosphorylation after starvation and mucin secretion. Therefore, K20 Ser(13) is a highly dynamic protein kinase C-related phosphorylation site that is induced during apoptosis and tissue injury. K20 Ser(13) phosphorylation also serves as a unique marker of small intestinal goblet cells.

Animals↗
PubMed2000

Developmental and lesion-induced changes in the distribution of the glucose transporter Glut-1 in the central and peripheral nervous system.

The active transport of D-glucose from the vascular to the neural compartment requires the presence of a carrier molecule at the blood-brain and the blood-nerve barrier. The glucose transporter 1 (Glut-1) seems to be the main carrier in blood-tissue barriers of endothelial and perineurial type. The distribution of Glut-1 was assessed in the normal central and peripheral nervous system of young and adult animals and compared with changes after nerve injury. Immuno-histochemistry, in situ hybridization, and perfusions with Evans Blue were carried out. Glut- I was not expressed in the perineurium of peripheral nerves at birth, but appeared in the perineurium of peripheral nerves, spinal roots, in the capsule of dorsal-root ganglia, and in the pia mater of adult animals. The perineurium of peripheral nerves subjected to Wallerian degeneration presented a faint Glut-1 immunoreaction, which was restored after regeneration. Glut-1 was expressed in capillaries of the gray substance of the spinal cord. Perineurial-derived lamellar cells of Pacinian corpuscles exhibited a strong Glut-1-like immunoreactivity in response to denervation and during development. Merkel cells and Meissner corpuscles were found to be Glut-1 negative. Glut-1 seems to reflect the quality of an adult, mature perineurial and blood-nerve barrier.

Adult↗
PubMed1994

Distribution and chemical phenotypes of neuroendocrine cells in the human anal canal.

The presence, morphology and distribution of anal neuroendocrine cells were investigated with a panel of antisera and antibodies for neural markers, biogenic amines, and neuropeptides by the sensitive streptavidin-biotin-peroxidase immunocytochemistry, and coexistence patterns of neurochemically characterized neuroendocrine cells were examined by double immunofluorescence cytochemistry. In the colorectal zone, endocrine-like cells were immunoreactive for chromogranin A (CGA), serotonin (5-HT), pancreastatin (PST), peptide tyrosine tyrosine (PYY), glucagon-like peptide-1 (GLP-1), and somatostatin (SOM). Coexistence patterns of endocrine-like cell phenotypes with CGA and GLP-1 were heterogeneous. In the anal transitional zone (ATZ), endocrine-like cells were immunoreactive for CGA, 5-HT and PST. Furthermore, six new phenotypes of endocrine-like cells were characterized by their immunoreactivity for PYY, GLP-1, protein gene product 9.5 (PGP), calcitonin gene-related peptide (CGRP), neurotensin (NT), and SOM. All endocrine-like cell types in the ATZ were immunoreactive for CGA. In the squamous zone and perianal skin, CGA-immunopositive Merkel cells were also immunoreactive for CGRP, PST, NT and PGP. Neuroendocrine cells in the anal canal exhibit epithelial zone-related diversities in their neurochemical phenotypes and coexistence patterns, which may indicate specific regulatory functions. In the epithelium of the ATZ, which is regarded as metaplastic, endocrine-like cells expressed phenotypes characteristic of the neuroendocrine cells of the colorectal zone and the squamous zones, indicating a possible metaplastic origin of these cells.

Adolescent↗
PubMed1992

Histochemistry of the human hair follicle with consideration of anagen phases I to VI.

The hair follicle is composed of different epithelial layers under participation of mesenchymal and nerval factors. The present study is an attempt to localize differentiation and functional markers in the human hair follicle during anagen phases I to VI. Monoclonal antibody K 8.12 against keratins 13 and 16 showed an increasing reactivity with certain types of the follicle epithelia during anagen I to VI. Ki67 was expressed within the innermost layer of the outer hair root sheath. Scattered Ki67-positive matrix cells could be additionally identified during anagen V and VI but were absent in anagen I to IV. During anagen Merkel cells became more abundant in the bulbar area. Neuropeptide-like immunoreactivity expressed by bulbar (especially matrix) cells were evenly seen during the early anagen I and II. The findings are in favour of a neurohumoral modulatory role during anagen phases accompanied by an increase of expression of certain proliferation-associated antigens like keratin 16 and Ki67 among the complex epithelia of human hair follicles.

Antibodies↗
PubMed1998

Sensory receptors in monotremes.

This is a summary of the current knowledge of sensory receptors in skin of the bill of the platypus, Ornithorhynchus anatinus, and the snout of the echidna, Tachyglossus aculeatus. Brief mention is also made of the third living member of the monotremes, the long-nosed echidna, Zaglossus bruijnii. The monotremes are the only group of mammals known to have evolved electroreception. The structures in the skin responsible for the electric sense have been identified as sensory mucous glands with an expanded epidermal portion that is innervated by large-diameter nerve fibres. Afferent recordings have shown that in both platypuses and echidnas the receptors excited by cathodal (negative) pulses and inhibited by anodal (positive) pulses. Estimates give a total of 40,000 mucous sensory glands in the upper and lower bill of the platypus, whereas there are only about 100 in the tip of the echidna snout. Recording of electroreceptor-evoked activity from the brain of the platypus have shown that the largest area dedicated to somatosensory input from the bill, S1, shows alternating rows of mechanosensory and bimodal neurons. The bimodal neurons respond to both electrosensory and mechanical inputs. In skin of the platypus bill and echidna snout, apart from the electroreceptors, there are structures called push rods, which consist of a column of compacted cells that is able to move relatively independently of adjacent regions of skin. At the base of the column are Merkel cell complexes, known to be type I slowly adapting mechanoreceptors, and lamellated corpuscles, probably vibration receptors. It has been speculated that the platypus uses its electric sense to detect the electromyographic activity from moving prey in the water and for obstacle avoidance. Mechanoreceptors signal contact with the prey. For the echidna, a role for the electrosensory system has not yet been established during normal foraging behaviour, although it has been shown that it is able to detect the presence of weak electric fields in water. Perhaps the electric sense is used to detect moving prey in moist soil.

Animals↗
PubMed1984

Neuroendocrine carcinoma of skin with simultaneous cytokeratin expression.

An unusual tumor of the skin was removed from the thigh of a 52-year-old white male. By light microscopy, the tumor was composed of intermediate and small cells in sheets and clusters. Ultrastructural study of the tumor cells showed numerous dense core granules and dendritic cell processes as well as intermediate filaments and cell junctions frequently within the same cells. Most of the tumor cells were stained intensely by antibodies to neurone-specific enolase (NSE), a marker of cells of the central and peripheral nervous system. The neuropeptides met-enkephalin and vasoactive intestinal peptide (VIP) were also found in tumor cells. Immunohistochemistry furthermore demonstrated cytokeratin. Both the ultrastructural appearance and keratin content of this tumor set it apart from conventional Merkel cell (or trabecular) carcinoma of the skin in a manner analogous to bipartite (i.e., epidermoid and small cell) carcinoma of lung. The production of neuropeptides simultaneously with the production of keratin establishes this as a bipartite skin tumor (i.e., ectodermal and neuroectodermal phenotype). We suggest that at least some primary neuroendocrine tumors of the skin arise from multipotential ectodermal cells not of neural crest origin, as has been proposed for small cell carcinoma of lung.

Apudoma↗
PubMed1984

Detection of chromogranin in neuroendocrine cells with a monoclonal antibody.

A monoclonal antibody ( LK2H10 ) produced against a human pheochromocytoma reacted immunohistochemically with 126 normal and neoplastic endocrine tissues with secretory granules which were formalin-fixed and paraffin-embedded. Antibody LK2H10 did not react with 46 other endocrine tissues or tumors without secretory granules nor with 113 normal and neoplastic nonendocrine cells and tumors. Tumors with abundant secretory granules showed intense and diffuse staining, and tumors with few granules, such as Merkel cell carcinomas, neuroblastomas, and small cell carcinomas of lung, showed focal staining. Antibody LK2H10 did not react with melanomas, nevi, posterior pituitary, peripheral nerve tissues, or neurons. The target structure of LK2H10 was identified as human chromogranin, of which the major fraction was chromogranin A (mol wt 68,000 daltons). Preabsorption with purified chromogranin A blocked immunoperoxidase staining by LK2H10 in normal adrenal medulla, in the anterior pituitary, and in a pheochromocytoma. Ultrastructural immunohistochemistry with LK2H10 showed that chromogranin was present in cytoplasmic secretory granules. These results indicate that chromogranin is widely distributed in the secretory granules of most polypeptide-producing endocrine tissues, and it is readily detected with the use of monoclonal antibody LK2H10 . The detection of this marker can be very helpful as a diagnostic aid for neuroendocrine cells and tumors.

Adrenal Gland Neoplasms↗
PubMedDate not supplied

[Epidermal keratinocyte proliferation, differentiation and apoptosis in rats in postnatal ontogeny].

Quantitative ratios between reproduction of the keratinocytes and their apoptotic death vary in different periods of postnatal ontogenesis. During the first month of life of the rats the mitotic activity of keratinocytes and thickness of the epidermis gradually decrease. The epidermis undergoes further development, which terminates by the 30th day after birth. The number of apoptotic cells in the epidermis increases from the 1st until 16th day and that of intraepidermal lymphocytes from the 1st until 30th day. In 3-month old animals the peak of mitotic activity coincided with the enhanced apoptotic death of the keratinocytes. The anagen signs were noted in such animals. In the old rats the mitotic activity of the epidermal cells was markedly reduced with the increased rate of apoptosis of the keratinocytes and the decreased thickness of epidermis. Single Merkel cells were visualized in the epidermis using the silver plating technique. Hence, their role in apoptosis of the keratinocytes cannot be significant. The possibility of lymphocyte-associated apoptosis of the keratinocytes in the early postnatal ontogenesis of rats is assumed.

Aging↗
PubMed1977

Neural-epithelial interactions in sensory receptors.

The specific types of relationships that exist between sensory nerve fibers and the associated epithelial cells have been reviewed in a variety of sensory systems. In many sensory systems, perhaps most, specificity of terminal epithelial element provides a degree of specificity to the cytologic pattern of the terminal receptor. We can see examples of such interaction, not only in the case of intraepithelial nerve fibers where nerves tend to be associated with Merkel cells, but also in the case of corpuscular receptors, both of these being examples of mechanosensory systems. Equivalent types of specificity are present within the special senses, where a specific receptor cell can be described. These findings strongly suggest that specificity in the peripheral nervous system is the rule rather than the exception, a thesis proposed over a hundred years ago by F. Merkel.

Animals↗
PubMed1987

Monoamine-containing basal cells in the taste buds of the newt Triturus pyrrhogaster.

Monoamine-containing cells were examined by fluorescence histochemistry and electron microscopy. Two or three serotonin-like fluorescent cells were located just above the basal lamina and failed to reach the free surface of the taste bud. Ultrastructurally this cell type was characterized by the presence of dense-cored vesicles and finger-like cytoplasmic processes. Many characteristics of Merkel cells were present.

Amines↗
PubMed1989

Chromogranin A and B messenger ribonucleic acids in pituitary and other normal and neoplastic human endocrine tissues.

The distribution of the messenger ribonucleic acids (mRNAs) for chromogranin A and B was analyzed by in situ hybridization in normal and neoplastic endocrine tissues using frozen and paraffin tissue sections. Combined in situ hybridization and immunochemical staining was also done on tissue sections from the same cases using a monoclonal antibody against chromogranin A (LK2H10). Most endocrine tumors expressed chromogranin A and B mRNAs as well as chromogranin A protein. Normal pituitary expressed chromogranin A and B mRNAs and chromogranin A protein in the anterior pituitary gland. Most of these cells were gonadotropic hormone-producing cells. Prolactinomas (5/5) did not express chromogranin A mRNA or protein, but contained chromogranin B mRNA. Null cell or nonfunctional adenomas (8/8) expressed chromogranin A and B mRNAs and reacted with antibody LK2H10. In some tumors such as Merkel cell carcinomas, insulinomas, and parathyroid adenomas, a stronger signal for chromogranin A mRNA was detected than for the immunoreactive proteins. These results indicate that in situ hybridization complements immunochemical techniques in the analysis of endocrine cells and neoplasms. The gene products for chromogranin A and B are widely distributed in many endocrine cells and tumors, but some neoplasms such as prolactinomas have a differential distribution of chromogranin A and B mRNA and proteins.

Blotting, Northern↗
PubMed2005

Cytokeratin 20-positive large cell neuroendocrine carcinoma of the colon.

Herein is presented a case of cytokeratin (CK) 20-positive large cell neuroendocrine carcinoma of the colon, in which the tumor was clinically at stage IV and located in the ascending colon. Pathological examination of the resected tumor revealed nested and solid proliferation of large undifferentiated cells with vesicular nucleus and prominent nucleoli. No areas showed differentiation toward adenocarcinoma or squamous cell carcinoma. Tumor cells were immunohistochemically positive for chromogranin A, synaptophysin, CD 56 (focal), and bore electron-dense granules. With these features, the tumor was diagnosed as a large cell neuroendocrine carcinoma of the colon. Liver metastasis and local recurrence progressed, and the patient died of the primary disease 7 months after operation. The autopsy confirmed this diagnosis without detectable tumors in the lungs. Interestingly, more than half of the tumor cells were positive for CK 20, while CK 7 was not expressed. Most neuroendocrine carcinomas do not express CK 20, with the exception of Merkel cell carcinomas, and most colorectal adenocarcinomas express CK 20. To the best of the authors' knowledge, the present case is the first CK 20-positive, CK 7-negative colorectal neuroendocrine carcinoma to be described, suggesting a link between colorectal neuroendocrine carcinoma and conventional adenocarcinoma.

Aged↗
PubMed1988

Ultrastructure of the Eimer's organs of the Japanese shrew mole, Urotrichus talpoides (Insectivora, Mammalia) and their changes following infraorbital axotomy.

The Eimer's organ and adjacent structures and their changes after infraorbital axotomy was examined with LM, TEM and SEM in the Japanese shrew mole, Urotrichus talpoides. Approximately 3,000 of Eimer's organ covers the hairless snout tip of this animal. It protrudes to the corium from epidermis, and consists of column-shaped core and the cylindrical peripheral structures. About a dozen of naked fibers ascend vertically in the core; one or a few of them runs amidst the core and the others along its circumferential part. Each fiber has shelf-like endings one in each of 5 to 7 succeeding cells in the upper part of the core. At the uppermost part of the core structure is an opaque degenerating cell. Neurites were considered to grow up with the epidermal cells to which their endings are attached. This pattern of nerve ending was clearly observed for the first time in this study. Usually 3 Merkel cells lie at the base of an Eimer's organ contacting with a soup-plate-shape nerve terminal. In the dermis, an encapsulated corpuscle enveloping a nerve endings is found underneath each Eimer's organ. After axotomy, ipsilateral nerve fibers and their endings totally disappeared from Eimer's organ in a week. Perforation in the domes, flattening of the dome surface, and degeneration of the encapsulated corpuscles appeared on the transected side. In addition to this, several features of degeneration also appeared on the contralateral side. It might be considered as an effect of disuse from the disorders of the other side.

Animals↗
PubMed1986

Coexpression of neurofilament and keratin proteins in cutaneous neuroendocrine carcinoma cells.

Four cases of neuroendocrine carcinomas (NECA) of the skin were studied by indirect immunofluorescence, using a monoclonal antikeratin antibody and a polyclonal antineurofilament antibody. Fifty to ninety percent and 80 to greater than 95% of the NECA cells stained with the antineurofilament antibody and the antikeratin antibody, respectively. Using double-labeling indirect immunofluorescence we could also demonstrate that, in 3 cases studied, some of the NECA cells, but not all, stained with both antikeratin and antineurofilament antibodies. These results, together with the recent knowledge of the intermediate filament protein type of normal Merkel cells (MC), tend to support the hypothesis that NECA cells do not originate from epithelial MC but from dermal neuroendocrine cells. A dual concept of intraepithelial MC and extraepithelial intradermal neuroendocrine cells, "from possible distinct origin," is proposed. Such a system has already been suggested for the neuroendocrine cells of the appendix and bronchial mucosae.

Adenocarcinoma↗
PubMed1997

Serotonin modulates voltage-dependent calcium current in Necturus taste cells.

Necturus taste buds contain two primary cell types: taste receptor cells and basal cells. Merkel-like basal cells are a subset of basal cells that form chemical synapses with taste receptor cells and with innervating nerve fibers. Although Merkel-like basal cells cannot interact directly with taste stimuli, recent studies have shown that Merkel-like basal cells contain serotonin (5-HT), which may be released onto taste receptor cells in response to taste stimulation. With the use of whole cell voltage clamp, we examined whether focal applications of 5-HT to isolated taste receptor cells affected voltage-activated calcium current (I(Ca)). Two different effects were observed. 5-HT at 100 microM increased I(Ca) in 33% of taste receptor cells, whereas it decreased I(Ca) in 67%. Both responses used a 5-HT receptor subtype with a pharmacological profile similar to that of the 5-HT1A receptor, but the potentiation and inhibition of I(Ca) by 5-HT were mediated by two different second-messenger cascades. The results indicate that functional subtypes of taste receptor cells, earlier defined only by their sensitivity to taste stimuli, may also be defined by their response to the neurotransmitter 5-HT and suggest that 5-HT released by Merkel-like basal cells could modulate taste receptor function.

Animals↗
PubMed1991

Localization of calcitonin gene-related peptide in human esophageal Langerhans cells.

Previously undescribed calcitonin gene-related peptide-immunoreactive intraepithelial cells were seen in specimens of esophageal mucosa obtained by biopsy or surgical resection from 14 individuals. These calcitonin gene-related peptide-immunoreactive cells were sparsely seen in normal mucosa but increased markedly in esophagitis. They were inaccessible to routine histological stains, but osmication showed them as dendritic forms resembling Langerhans cells of the skin. Their cytological identity was determined with immunocytochemical tests for human antigenic markers such as Ia, HLA-DR, and OKT6 for Langerhans cells, Leu-M5 and Leu-M3 for intraepithelial macrophages, CD3 and TCR-1 for T-lymphocytes, Leu-14 for B-lymphocytes, S-100 for Merkel cells, and chromogranin for amine precursor uptake and decarboxylation cells. Double localization showed that calcitonin gene-related peptide immunoreactivity colocalized with Ia, HLA-DR, and OKT6 but not with the other markers. These studies show that intraepithelial Langerhans cells in the esophageal mucosa contain calcitonin gene-related peptide, which may serve as an immunomodulator.

Calcitonin Gene-Related Peptide↗
PubMedDate not supplied

Neuronal intermediate filaments in the developing tongue of the frog Rana esculenta.

The expression of several neuronal intermediate filament (NIF) proteins was investigated in the tongue of metamorphosing tadpoles (stage 38-45 of Gosner) and in adult individuals of the frog, Rana esculenta by means of immunohistochemistry. Results showed that nerve fibres at early stages of tongue development expressed peripherin (a NIF protein usually found in differentiating neurones) as well as the light- and medium molecular weight NIF polypeptide subunits (NF-L and NF-M, respectively); in the adult frog, peripherin was still found in nerve fibres reaching the fungiform papilla together with NF-M, but NF-L immunoreactivity was absent therein. Clusters of epithelial cells expressing peripherin were found in the early developing tongue before differentiation of taste organs, and NF-L and NF-H immunoreactivities were present in basal (Merkel) cells of the adult frog taste disc. Results indicate that neurones innervating the adult frog's taste disc maintain a certain plasticity in their cytoskeleton and that neuronal-like cells are present in the undifferentiated and differentiated tongue epithelium possibly playing a role in the developing and mature taste organ.

Animals↗
PubMed1983

Expression of Thy-1 antigen by murine epidermal cells.

We report on the occurrence of a cell population within the murine epidermis which, by both morphologic and surface property criteria, is distinct from all other epidermal cell types known so far. These previously unrecognized cells are evenly distributed within the epidermis, display a primarily dendritic shape, exhibit a lobulated nucleus, contain large amounts of vimentin type intermediate-sized filaments, but lack desmosomes, melanosomes, Merkel cell granules, and Birbeck granules. As opposed to melanocytes, these cells fail to display tyrosinase activity. Surface marker analysis reveals these cells to uniformly express the Thy-1 antigen and to lack I-A and I-E/C antigen specificities. A major portion of these Thy-1-bearing cells are reactive with a monoclonal antibody to the Ly-5 determinant whereas attempts to demonstrate Lyt-1,2,3 antigens consistently yield negative results. These findings strongly suggest that Thy-1+ epidermal cells originate from the bone marrow; however, their precise relationship to distinct members of the hemopoietic differentiation pathway remains to be established.

Animals↗