RESUMEN
In our previous study, the sphingosine-like immunosuppressant ISP-1 was shown to induce apoptosis in the mouse cytotoxic T cell line CTLL-2. In this study, we characterized the ISP-1-induced apoptotic pathway. Although caspase-3-like protease activity increases concomitantly with ISP-1-induced apoptosis in CTLL-2 cells, the apoptosis is not inhibited by caspase-3-like protease inhibitors, i.e. DEVD-cho and z-DEVD-fmk. In contrast, sphingosine-induced apoptosis in CTLL-2 cells is caspase-3-like protease-dependent. A caspase inhibitor with broad specificity, z-VAD-fmk, protects cells from apoptosis induced by ISP-1, indicating that ISP-1-induced apoptosis is dependent on caspase(s) other than caspase-3. Overexpression of Bcl-2 or Bcl-xL suppresses the apoptosis induced by ISP-1, although sphingosine-induced apoptosis is not efficiently inhibited by Bcl-2. Finally, ISP-1-induced mitochondrial depolarization, which is thought to be a checkpoint dividing the apoptotic pathway into upstream and downstream stages, is not inhibited by DEVD-cho, but is inhibited by z-VAD-fmk. These data suggest that a pathway dependent on caspase(s) other than caspase-3 is involved upstream of mitochondrial depolarization in ISP-1-induced apoptosis.
Asunto(s)
Apoptosis/efectos de los fármacos , Caspasas/metabolismo , Ácidos Grasos Monoinsaturados/farmacología , Inmunosupresores/farmacología , Linfocitos T Citotóxicos/efectos de los fármacos , Animales , Caspasa 3 , Inhibidores de Caspasas , Línea Celular , Supervivencia Celular/efectos de los fármacos , Inhibidores de Cisteína Proteinasa/farmacología , Potenciales de la Membrana/efectos de los fármacos , Ratones , Mitocondrias/efectos de los fármacos , Mitocondrias/metabolismo , Oligopéptidos/farmacología , Proteínas Proto-Oncogénicas c-bcl-2/genética , Proteínas Proto-Oncogénicas c-bcl-2/metabolismo , Esfingolípidos/farmacología , Linfocitos T Citotóxicos/citología , Linfocitos T Citotóxicos/enzimología , Proteína bcl-XRESUMEN
Although a number of cellular components of cytokinesis have been identified, little is known about the detailed mechanisms underlying this process. Here, we report that the lipid metabolite psychosine (galactosylsphingosine), derived from galactosylceramide, induced formation of multinuclear cells from a variety of nonadherent and adherent cells due to inhibition of cytokinesis. When psychosine was added to the human myelomonocyte cell line U937, which was the most sensitive among the cell lines tested, cleavage furrow formed either incompletely or almost completely. However, abnormal contractile movement was detected in which the cellular contents of one of the hemispheres of the contracting cell were transferred into its counterpart. Finally, the cleavage furrow disappeared and cytokinesis was reversed. Psychosine treatment also induced giant clots of actin filaments in the cells that probably consisted of small vacuoles with filamentous structures, suggesting that psychosine affected actin reorganization. These observations could account for the formation of multinuclear globoid cells in the brains of patients with globoid cell leukodystrophy, a neurological disorder characterized by the accumulation of psychosine due to galactosylceramidase deficiency.
Asunto(s)
División Celular/efectos de los fármacos , Psicosina/farmacología , Actinas/efectos de los fármacos , Actinas/ultraestructura , Humanos , Leucodistrofia de Células Globoides/etiología , Fagocitosis/efectos de los fármacos , Fosforilcolina/análogos & derivados , Fosforilcolina/farmacología , Psicosina/análogos & derivados , Esfingosina/análogos & derivados , Esfingosina/farmacología , Células Tumorales Cultivadas , Células U937RESUMEN
ISP-1 is a new type of immunosuppressant, the structure of which is homologous to that of sphingosine. In a previous study, ISP-1 was found to inhibit mammalian serine palmitoyltransferase, the primary enzyme involved in sphingolipid biosynthesis, and to reduce the intracellular pool of sphingolipids. ISP-1 induces the apoptosis of cytotoxic T cells, which is triggered by decreases in the intracellular levels of sphingolipids. In this study, the inhibition of yeast (Saccharomyces cerevisiae) proliferation by ISP-1 was observed. This ISP-1-induced growth inhibition was also triggered by decreases in the intracellular levels of sphingolipids. In addition, DNA duplication without cytokinesis was detected in ISP-1-treated yeast cells on flow cytometry analysis. We have cloned multicopy suppressor genes of yeast which overcome the lethal sphingolipid depletion induced by ISP-1. One of these genes, SLI2, is synonymous with YPK1, which encodes a serine/threonine kinase. Kinase-dead mutants of YPK1 did not show any resistance to ISP-1, leading us to predict that the kinase activity of the Ypk1 protein should be essential for this resistance to ISP-1. Ypk1 protein overexpression had no effect on sphingolipid biosynthesis by the yeast. Furthermore, both the phosphorylation and intracellular localization of the Ypk1 protein were regulated by the intracellular sphingolipid levels. These data suggest that the Ypk1 protein is a downstream kinase in the sphingolipid-mediated signaling pathway of yeast. The Ypk1 protein was reported to be a functional homologue of the mammalian protein kinase SGK, which is a downstream kinase of 3-phosphoinositide-dependent kinase 1 (PDK1). PDK1 phosphotidylinositol (PI) is regulated by PI-3,4,5-triphosphate and PI-3,4-bisphosphate through the pleckstrin homology (PH) domain. Overexpression of mammalian SGK also overcomes the sphingolipid depletion in yeast. Taking both the inability to produce PI-3,4, 5-triphosphate and PI-3,4-bisphosphate and the lack of a PH domain in the yeast homologue of PDK1, the Pkh1 protein, into account, these findings further suggest that yeast may use sphingolipids instead of inositol phospholipids as lipid mediators.
Asunto(s)
Ácidos Grasos Monoinsaturados/farmacología , Proteínas Fúngicas/fisiología , Inmunosupresores/farmacología , Proteínas Nucleares , Proteínas Tirosina Quinasas/fisiología , Proteínas de Saccharomyces cerevisiae , Saccharomyces cerevisiae/fisiología , Transducción de Señal , Glucógeno Sintasa Quinasa 3 , Proteínas Inmediatas-Precoces , Proteínas Serina-Treonina Quinasas/fisiologíaRESUMEN
9-O-Acetylation is one of the most common modifications of sialic acids, and it can affect several sialic acid-mediated recognition phenomena. We previously reported a cDNA encoding a lysosomal sialic acid-specific 9-O-acetylesterase, which traverses the endoplasmic reticulum-Golgi pathway and localizes primarily to lysosomes and endosomes. In this study, we report a variant cDNA derived from the same gene that contains a different 5' region. This cDNA has a putative open reading frame lacking a signal peptide-encoding sequence and is thus a candidate for the previously described cytosolic sialic acid 9-O-acetylesterase activity. Epitope-tagged constructs confirm that the new sequence causes the protein product to be targeted to the cytosol and has esterase activity. Using reverse transcription-polymerase chain reaction to distinguish the two forms of message, we show that although the lysosomal sialic acid-specific 9-O-acetylesterase message has a widespread pattern of expression in adult mouse tissues, this cytosolic sialic acid 9-O-acetylesterase form has a rather restricted distribution, with the strongest expression in the liver, ovary, and brain. Using a polyclonal antibody directed against the 69-amino acid region common to both proteins, we confirmed that the expression of glycosylated and nonglycosylated polypeptides occurred in appropriate subcellular fractions of normal mouse tissues. Rodent liver polypeptides reacting to the antibody also co-purify with previously described lysosomal sialic acid esterase activity and at least a portion of the cytosolic activity. Thus, two sialic acid 9-O-acetylesterases found in very different subcellular compartments can be encoded by a single gene by differential usage of a signal peptide-encoding exon at the N terminus. The 5'-rapid amplification of cDNA ends results and the differences in tissue-specific expression suggest that expression of these two products may be differentially regulated by independent promoters.
Asunto(s)
Hidrolasas de Éster Carboxílico/genética , Citosol/enzimología , Regulación Enzimológica de la Expresión Génica , Lisosomas/enzimología , Acetilesterasa , Secuencia de Aminoácidos , Animales , Secuencia de Bases , Células COS , Hidrolasas de Éster Carboxílico/metabolismo , Exones , Ratones , Datos de Secuencia MolecularRESUMEN
Although alpha(1)-antitrypsin (AAT) deficiency is one of the most common hereditary diseases and a recognized cause of emphysema in Caucasians, variants of this deficiency are extremely rare among Orientals. We present here a Japanese emphysema patient with the AAT deficiency variant originally identified as S(iiyama). After an 8-year follow-up period, the patient suffered from repeated pulmonary Pseudomonas aeruginosa infection for 4 years. He died suddenly of massive pulmonary hemorrhage. The pathologic examination revealed a necrotic hematoma in the right S10 lobe, which exhibited pneumonia due to cytomegalovirus (CMV) infection. Pulmonary hemorrhage due to CMV can occur and be fatal in patients with emphysema and AAT deficiency.
Asunto(s)
Infecciones por Citomegalovirus/complicaciones , Hemorragia/etiología , Neumonía Viral/complicaciones , Enfisema Pulmonar/complicaciones , Deficiencia de alfa 1-Antitripsina/complicaciones , Adulto , Humanos , Enfermedades Pulmonares/etiología , MasculinoRESUMEN
We describe the case of a 53-year-old Philadelphia-chromosome-positive woman with chronic myelogenous leukemia, who developed pulmonary alveolar proteinosis (PAP). The possible mechanism involved in the pathogenesis of PAP are discussed based on the clinical and laboratory data for this patient as well as on experimental and clinical data reported in the literature.
Asunto(s)
Leucemia Mielógena Crónica BCR-ABL Positiva/complicaciones , Proteinosis Alveolar Pulmonar/etiología , Análisis Químico de la Sangre , Lavado Broncoalveolar , Broncoscopía , Progresión de la Enfermedad , Resultado Fatal , Femenino , Humanos , Leucemia Mielógena Crónica BCR-ABL Positiva/diagnóstico , Persona de Mediana Edad , Proteinosis Alveolar Pulmonar/diagnóstico , Insuficiencia RespiratoriaRESUMEN
A 17-year-old girl was admitted to our hospital due to low-grade fever, confusion, numbness in her right hand and automatism. On admission, she was slightly disoriented but there were no meningeal signs. Weakness and sensory disturbance were observed in her right hand. Automatism and clonic seizures frequently appeared. Electroencephalography revealed frequent delta bursts in her left frontal lobe. 123I-IMP-SPECT study showed abnormally increased isotope uptake in the left cerebral hemisphere. She was diagnosed as status epilepticus of left frontal lobe origin and treated with anti-convulsants including carbamazepine, phenytoin, diazepam, phenobarbital, and thiopental, which were not effective. Then we started corticosteroid therapy. Three cycles of intravenous injections of methylprednisolone, followed by oral prednisolone led to marked improvement in her symptoms. It is known that corticosteroid decreases the threshold of seizure, so we do not use it for idiopathic epilepsy. On the other hand, in some secondary epilepsy due to vasculitis in the brain, corticosteroid is very effective for seizures. It is still unclear whether our patient actually had vasculitis or not. However, it is important to recognize that steroid therapy might be effective in a certain portion of epilepsies resistant to anti-convulsants, especially in young patients with non-infectious fever.
Asunto(s)
Antiinflamatorios/administración & dosificación , Epilepsia del Lóbulo Frontal/tratamiento farmacológico , Metilprednisolona/administración & dosificación , Prednisolona/administración & dosificación , Estado Epiléptico/tratamiento farmacológico , Administración Oral , Adolescente , Femenino , HumanosRESUMEN
Sialic acids are important cell-surface molecules of animals in the deuterostome lineage. Although humans do not express easily detectable amounts of N-glycolylneuraminic acid (Neu5Gc, a hydroxylated form of the common sialic acid N-acetylneuraminic acid, Neu5Ac), it is a major component in great ape tissues, except in the brain. This difference correlates with lack of the hydroxylase activity that converts CMP-Neu5Ac to CMP-Neu5Gc. Here we report cloning of human and chimpanzee hydroxylase cDNAs. Although this chimpanzee cDNA is similar to the murine homologue, the human cDNA contains a 92-bp deletion resulting in a frameshift mutation. The isolated human gene also shows evidence for this deletion. Genomic PCR analysis indicates that this deletion does not occur in any of the African great apes. The gene is localized to 6p22-p23 in both humans and great apes, which does not correspond to known chromosomal rearrangements that occurred during hominoid evolution. Thus, the lineage leading to modern humans suffered a mutation sometime after the common ancestor with the chimpanzee and bonobo, potentially affecting recognition by a variety of endogenous and exogenous sialic acid-binding lectins. Also, the expression of Neu5Gc previously reported in human fetuses and tumors as well as the traces detected in some normal adult humans must be mediated by an alternate pathway.
Asunto(s)
Evolución Molecular , Hominidae/genética , Oxigenasas de Función Mixta/genética , Mutación , Secuencia de Aminoácidos , Animales , Secuencia de Bases , Clonación Molecular , Cartilla de ADN/genética , ADN Complementario/genética , Humanos , Hibridación Fluorescente in Situ , Ratones , Datos de Secuencia Molecular , Pan troglodytes/genética , Homología de Secuencia de Aminoácido , Homología de Secuencia de Ácido NucleicoRESUMEN
Cytidine monophospho-N-acetylneuraminic acid (CMP-NeuAc) hydroxylase is a key enzyme for the expression of N-glycolylneuraminic acid. The molecular cloning of this enzyme from mouse liver has been described in our previous report (Kawano T, Koyama S, Takematsu H, Kozutsumi Y, Kawasaki H, Kawashima S, Kawasaki T, Suzuki A (1995) J Biol Chem 270: 16458-63). During the cDNA cloning, a cDNA containing a truncated open reading frame (ORF) was isolated. This clone encodes a protein of 531 amino acids which lacks 46 amino acids in the middle of the normal full-length protein. The percentage of this mRNA containing the truncated ORF out of the total population of CMP-NeuAc hydroxylase mRNA in various mouse tissues was about 10-25%. The truncated protein was expressed in COS-1 cells, but did not show any enzymatic activity. The truncated protein was localized to the region which appeared to be the endoplasmic reticulum, whereas the full-length protein with normal enzymatic activity was detected in the cytosol. These data suggest that this naturally occurring 46-amino acid deletion leads to a change in the intracellular distribution of CMP-NeuAc hydroxylase, and a loss in the activity of this enzyme.
Asunto(s)
Oxigenasas de Función Mixta/biosíntesis , Oxigenasas de Función Mixta/genética , Eliminación de Secuencia , Secuencia de Aminoácidos , Animales , Secuencia de Bases , Células COS , Chlorocebus aethiops , Cartilla de ADN , Técnica del Anticuerpo Fluorescente Indirecta , Hígado/enzimología , Ratones , Oxigenasas de Función Mixta/química , Datos de Secuencia Molecular , Sistemas de Lectura Abierta , Reacción en Cadena de la Polimerasa , Proteínas Recombinantes/biosíntesis , Fracciones Subcelulares/enzimología , TransfecciónRESUMEN
In mammals, two forms of cytochrome b5 (b5) are present and they are called according to their subcellar distribution as the microsomal-form and the soluble-form. These two forms of b5 s were encoded by separate mRNAs. In order to elucidate the mechanism of the expression of these two mRNAs, we isolated genomic clones that cover the gene for b5 from the rabbit genomic library. Analysis of these clones revealed that b5 gene spans over 20kbase pairs. A solube-form specific exon was found to be present between the two exons, which are in common to both forms of b5s. These observation demonstrate that the two forms of b5 mRNA are derived from the same gene by the alternative exon skip splicing.
Asunto(s)
Citocromos b5/genética , Animales , Secuencia de Bases , ADN , Datos de Secuencia Molecular , ConejosRESUMEN
Cytidine monophospho-N-acetylneuraminic acid (CMP-NeuAc) hydroxylase, which is the key enzyme for the synthesis of N-glycolylneuraminic acid (NeuGc), has been purified from the cytosolic fraction of mouse liver, as described in our previous paper. The amino acid sequences of the purified CMP-NeuAc hydroxylase, and peptides obtained by lysylendopeptidase digestion, were used to synthesize specific oligonucleotide primers. A mouse cDNA clone of the enzyme was obtained by a combination of the polymerase chain reaction and rapid amplification of cDNA ends. The sequence of the clone contained an open reading frame coding for a protein of 577 amino acids with a predicted molecular mass of 66 kDa. The deduced sequence included the amino acid sequences obtained for the purified enzyme and peptides, and a complete match was obtained for 159 residues. The enzyme has neither a signal peptide sequence nor a membrane spanning domain, which is consistent with localization of the enzyme in the cytosol. Transfection of a cDNA construct to COS-1 cells increased the enzyme activity and the amount of NeuGc. Comparison of the sequence with GenBank data indicated that no similar sequence has been reported so far. Northern blot analysis of various mouse tissues with the enzyme cDNA as a probe indicated that expression of NeuGc is related to the level of CMP-NeuAc hydroxylase mRNA. On Southern blot analysis with the same probe, cross-hybridizing bands were detected in the human and fish genomes.
Asunto(s)
Ácido N-Acetilneuramínico Citidina Monofosfato/metabolismo , Oxigenasas de Función Mixta/genética , Secuencia de Aminoácidos , Animales , Secuencia de Bases , Northern Blotting , Southern Blotting , Clonación Molecular , Humanos , Hígado/enzimología , Ratones , Oxigenasas de Función Mixta/biosíntesis , Datos de Secuencia Molecular , Ácidos Neuramínicos/metabolismo , Fragmentos de Péptidos/química , Reacción en Cadena de la Polimerasa , ARN Mensajero/genética , Proteínas Recombinantes/biosíntesis , Análisis de Secuencia , Especificidad de la Especie , Distribución TisularRESUMEN
We have proposed that CMP-N-acetylneuraminic acid (CMP-NeuAc) hydroxylation is mediated by an electron transport system consisting of cytochrome b5 (b5), b5 reducing factor(s), and CMP-NeuAc hydroxylase, all of which have been detected in the cytosolic fraction of mouse liver [Kozutsumi, Y., Kawano, T., Yamakawa, T., & Suzuki, A. (1990) J. Biochem. 108, 704-706]. In order to elucidate the reaction mechanism underlying CMP-NeuAc hydroxylation, the interaction between b5 and the hydroxylase was studied using a b5-immobilized affinity column. The enzyme activity was retarded on the b5 column in the presence of the substrate, CMP-NeuAc, but not in the presence of the reaction product, CMP-N-glycolyneuraminic acid (CMP-NeuGc). These findings suggest that the binding of CMP-NeuAc to CMP-NeuAc hydroxylase changes the conformation of the enzyme so as to construct a recognition site for b5, followed by the formation of a ternary complex through this domain. Then the transport of electrons from NAD(P)H to the enzyme through b5 takes place, CMP-NeuAc is converted to CMP-NeuGc, and finally the ternary complex dissociates into its components to release CMP-NeuGc. It is known that a soluble form of b5 is abundant in erythrocytes and is synthesized from a mRNA different from that for the microsomal form of b5. In order to determine the origin of b5 detected in the cytosolic fraction of mouse liver, the molecular forms of b5 mRNA expressed in mouse liver were analyzed.(ABSTRACT TRUNCATED AT 250 WORDS)
Asunto(s)
Ácido N-Acetilneuramínico Citidina Monofosfato/metabolismo , Citocromos b5/metabolismo , Oxigenasas de Función Mixta/metabolismo , Animales , Secuencia de Bases , Citocromos b5/genética , ADN Complementario/genética , ADN Complementario/metabolismo , Electroforesis en Gel de Agar , Hidroxilación , Ratones , Ratones Endogámicos BALB C , Microsomas Hepáticos/metabolismo , Datos de Secuencia Molecular , ARN Mensajero/genética , ARN Mensajero/metabolismoRESUMEN
The histopathologic features of active psoriatic plaques are characterized by epidermal hyperplasia and the presence of inflammatory cells. Recently it has been strongly suggested that an increased local production of cytokines and growth factors by keratinocytes or by activated inflammatory infiltrates play an crucial role in the induction of these changes. Particularly keratinocytes are demonstrated to secrete several different immuno-inflammatory mediators, including interleukin 1 (IL-1), IL-6 and IL-8. IL-1 induces IL-6 production in vitro, which in turn stimulates the proliferation of human keratinocytes. Although IL-1 has been reported to be reduced in samples from psoriatic lesions, enhanced immunohistochemical expression of IL-6 has been shown in psoriatic lesional skin. Thus, we designed the present study to elucidate the paradoxical situation of IL-1 and IL-6 expression in psoriatic skin lesions by directly measuring these cytokines in tissue fluids collected from suction blisters as well as in horny tissue extracts. As reported before, the levels of immunoreactive IL-1-alpha or -1 beta tended to be reduced in the scale extracts of psoriasis and related pustular dermatoses. In contrast, the levels of immunoreactive IL-6 tended to be increased, despite the presence of great variations between samples, a significant elevation being found only in the scale extracts of pustular psoriasis. Although the mean of IL-6 levels in the suction blister fluids from psoriatic involved skin was higher than those from normal or psoriatic uninvolved skin, again no statistical significance was noted. Moreover, no significant correlation was observed between the levels of immunoreactive IL-1 and IL-6 in these materials. Our direct measurements of these cytokines in lesional tissue samples do not provide evidence suggesting any close interrelationship between IL-1 and IL-6 nor provided evidence suggesting a pivotal role for IL-6 in the pathogenetic mechanism of psoriasis.
Asunto(s)
Interleucina-1/metabolismo , Interleucina-6/metabolismo , Psoriasis/metabolismo , Piel/metabolismo , Adolescente , Adulto , Vesícula/metabolismo , Cromatografía en Gel , Cromatografía Líquida de Alta Presión , Femenino , Humanos , Técnicas para Inmunoenzimas , Interleucina-6/aislamiento & purificación , Masculino , Persona de Mediana EdadRESUMEN
An unusual case of verrucous carcinoma of the face with a massive infiltration of neutrophils was found in a 60-year-old Japanese man who presented with a scaly, crusty tumour studded with pustules of 3 years duration on the left cheek. Histological examination showed a proliferation of deceptively benign-looking epidermal cells with an intact basement membrane, accompanied by a dermal infiltration of neutrophils and mononuclear cells and formation of microabscesses containing multinucleate giant cells, suggesting deep fungal infection or blastomycosis-like pyoderma. The lesion, however, was unresponsive to antifungal or antibacterial treatments and ultimately attained a considerable size in the following months. Based on the findings of repeat biopsy conducted 4 months later indicating further deeper invasion, a diagnosis of verrucous carcinoma of the face was made, and a total excision of the tumour and left cervical lymph node dissection were finally carried out. It can be speculated that aberrant production of leucocyte chemotactic cytokines such as interleukin-8 by dysplastic keratinocytes, subsequent neutrophil infiltration/serum permeation, generation of leucotactic anaphylatoxin C5a from serum through complement activation and of lipid chemotactic factors (leukotriene B4 and 12-hydroxy-eicosatetraenoic acid) by infiltrating leucocytes and/or dysplastic keratinocytes provoked the characteristic accumulation of neutrophils in the verrucous carcinoma of this case.
Asunto(s)
Carcinoma Verrugoso/patología , Quimiotaxis de Leucocito , Neoplasias Faciales/patología , Neutrófilos/patología , Carcinoma Verrugoso/inmunología , Neoplasias Faciales/inmunología , Humanos , Queratinocitos/inmunología , Masculino , Persona de Mediana EdadRESUMEN
Molluscum contagiosum, a condition characterized by benign viral tumours, occasionally becomes inflamed and regresses spontaneously, an event probably initiated by a host cell-mediated immune rejection against the lesion, but it inevitably involves the disruption of the epidermal tissue to expose the molluscum bodies to the tissue fluids of the dermis. It has been suggested that the molluscum bodies induce inflammation by a mechanism similar to that involved in ruptured epidermal cysts or in acne. Despite the occasional development of inflammation in molluscum contagiosum, the proinflammatory properties of molluscum bodies have never been studied in vitro. Thus, in the present study we sought to determine whether molluscum bodies exert a proinflammatory effect by inducing neutrophil chemotaxis. When exposed to fresh serum in vitro, water-insoluble components of molluscum bodies activated the alternative complement pathway to produce chemotactic C5a/C5a des Arg. We also found that an aqueous extract of molluscum bodies exerted potent chemotactic activity for neutrophils. Remarkably high amounts of the immunoreactive proinflammatory cytokines IL-8 and GRO alpha were present in the extract even when compared with psoriatic scale extracts. Gel filtration HPLC of the extract demonstrated the presence of neutrophil chemotactic activity over a wide range of molecular mass. These data suggest that disruption of the epidermal wall of molluscum bodies induces acute inflammatory changes by activation of the alternative complement pathway on exposure to the tissue fluids, and that the molluscum bodies themselves release proinflammatory cytokines and other neutrophil chemotactic factors on decomposition.
Asunto(s)
Molusco Contagioso/patología , Quimiotaxis de Leucocito , Cromatografía , Complemento C5a/metabolismo , Citocinas/metabolismo , Humanos , Inflamación/patología , Molusco Contagioso/metabolismo , Neutrófilos/metabolismo , Neutrófilos/patología , RadioinmunoensayoRESUMEN
Keratinocytes have been shown to express interleukin-8 (IL-8) mRNA on stimulation with IL-1 and other substances. This has been assumed to account for the large amount of this neutrophil chemotactic cytokine in psoriasis. We found that, without any added agents, commercially available normal human epidermal keratinocytes proliferating in Keratinocyte Growth Medium (KGM) released a chemotactic peptide extracellularly, which was confirmed to be IL-8. To determine whether most of the IL-8 is secreted extracellularly from proliferating keratinocytes or is mainly stored to be released only on stimulation. We quantified cell-associated and released immunoreactive IL-8 from keratinocytes cultured in KGM for up to 11 days at the peptide level. The keratinocytes proliferated, taking a sigmoid growth curve, to reach a plateau at day 7. We found that the amounts of immunoreactive IL-8 gradually increased in the culture supernatant with cell growth but its prominent release took place only after the cell growth reached a plateau. The cell-associated IL-8 was much smaller in amount than that noted in the supernatant. These results suggest that IL-8 constitutively produced by keratinocytes was mostly released extracellular but that the production by actively proliferating cells seems to be far less than that by non-proliferating cells that probably occurred in an autocrine fashion under the stimulation of keratinocyte-derived cytokines accumulated in the culture medium. Neutrophil chemotactic activity assayed concomitantly showed a consistent increase during the culture period, indicating that, with their growth, the keratinocytes release substances other than IL-8 that exert an influence on neutrophil chemotactic functions.
Asunto(s)
Células Epidérmicas , Interleucina-8/metabolismo , Queratinocitos/metabolismo , División Celular , Células Cultivadas , Quimiotaxis de Leucocito/efectos de los fármacos , Humanos , Interleucina-8/farmacología , Neutrófilos/efectos de los fármacosRESUMEN
While the incidence of malignant melanoma is much lower in Japanese than in Caucasians, the commonest site of melanoma in Japanese has been reported to be the acral regions of the limbs. The survival rate for acral and nodular melanoma observed at the Department of Dermatology, Tohoku University Hospital in Sendai, Japan from 1969 to 1990 was reviewed. Among 150 melanoma patients 125 (83%) and 17 (11%) had primary cutaneous melanoma and mucous membrane melanomas, respectively. Frequent sites for cutaneous melanomas were the sole (31%) and subungual regions (15%). Comparison of the stages of plantar melanoma at diagnosis showed that the proportion of stages III and IV decreased after 1980 with a corresponding increase in those with a tumour thickness of less than 4 mm (stage II). Concurrently, the prognosis of plantar melanoma has improved; the 5-year survival rate in each of the three periods 1969-75, 1976-80 and 1981-85 was 21, 70 and 90%, respectively. This was also the case with subungual melanoma. Such improvements in the prognosis are thought to be mainly due to early detection through the growing public awareness of this life-threatening disease. By contrast cases of nodular melanoma increased sharply after 1980. Among these, the high proportion of patients in advanced stages (stages III and IV) remained static even after 1980, with a resultant low 5-year survival rate in the above mentioned periods of 33, 38 and 18%, respectively.
Asunto(s)
Enfermedades del Pie/mortalidad , Mano , Melanoma/mortalidad , Femenino , Humanos , Incidencia , Japón/epidemiología , Masculino , Persona de Mediana Edad , Pronóstico , Estudios Retrospectivos , Tasa de SupervivenciaRESUMEN
The hydroxylation of CMP-NeuAc has been demonstrated to be carried out by several factors including the soluble form of cytochrome b5. In the present study, mouse liver cytosol was subjected to ammonium sulfate fractionation and cellulose phosphate column chromatography for the separation of two other essential fractions participating in the hydroxylation. One of the fractions, which bound to a cellulose phosphate column, was able to reduce the soluble cytochrome b5, using NADH as an electron donor. The other fraction, which flowed through the column, was assumed to contain the terminal enzyme which accepts electrons from cytochrome b5, activates oxygen, and catalyses the hydroxylation of CMP-NeuAc. Assay conditions for the quantitative determination of the terminal enzyme were established, and the activity of the enzyme in several tissues of mouse and rat was measured. The level of the terminal enzyme activity is associated with the expression of N-glycolylneuraminic acid in these tissues, indicating that the expression of the terminal enzyme possibly regulates the overall velocity of CMP-NeuAc hydroxylation.
Asunto(s)
Ácido N-Acetilneuramínico Citidina Monofosfato/química , Glicoconjugados/biosíntesis , NAD/fisiología , Ácidos Neuramínicos/análisis , Animales , Factores Biológicos/aislamiento & purificación , Fraccionamiento Químico , Citocromos b5/análisis , Glicoconjugados/química , Humanos , Hidroxilación , Ratones , Ratones Endogámicos DBA , Peso Molecular , Especificidad de Órganos/fisiología , Oxidación-Reducción , Ratas , SolubilidadRESUMEN
BACKGROUND AND DESIGN: Psoriatic scale extracts contain a unique chemotactic peptide fraction that is likely to be involved in the induction of rhythmic transepidermal leukocyte chemotaxis. Recent studies have identified the presence of two unrelated chemotactic peptides in this fraction, ie, C5a/C5a des Arg and interleukin 8 (IL-8), and its related cytokines. To investigate their relative contribution to the transepidermal leukocyte migration as well as their interrelationship in psoriatic lesions, we have quantified concentrations of immunoreactive C5a/C5a des Arg and IL-8 in psoriatic lesional scale extracts and those from related sterile pustular dermatoses such as subcorneal pustular dermatosis and pustulosis palmaris et plantaris. RESULTS: The concentrations of C5a/C5a des Arg and IL-8 were more significantly increased in the horny-tissue extracts from lesional skin than in those from noninflammatory orthokeratotic skin (P < .01). The increase of C5a/C5a des Arg concentration was specific to the lesional scale extracts, but showed a rather wide range of variation. By contrast, IL-8 concentration, although consistently increased in the lesional scale extracts, was also moderately increased even in noninflammatory scale extracts prepared from ichthyosis vulgaris. The elevation of IL-8 levels in psoriatic lesions was also confirmed by measuring their levels in cutaneous tissue fluid samples collected from suction blisters. However, unexpectedly, some control samples obtained from normal skin also showed a moderate increase in the IL-8 level. Neutrophil chemotactic activity correlated significantly only with the levels of C5a/C5a des Arg in the scales (P < .05). No such significant correlation was found between chemotactic activity and IL-8 or between C5a/C5a des Arg and IL-8. CONCLUSION: Based on these results, we speculate that, although IL-8 may exert a synergistic effect with C5a/C5a des Arg in the induction of transepidermal leukocyte chemotaxis, it constitutes a proinflammatory cytokine that is involved in the production of the persistent inflammatory changes characterized by a T-lymphocyte infiltration. In contrast, C5a/C5a des Arg seems to be generated only in the inflammatory lesional skin under specific circumstances that preferentially favor complement activation and also seems to play a major role in the induction of cyclic transepidermal leukocyte chemotaxis from "squirting papillae."
Asunto(s)
Factores Quimiotácticos/análisis , Complemento C5a des-Arginina/análisis , Interleucina-8/análisis , Psoriasis/metabolismo , Piel/química , Adolescente , Adulto , Quimiotaxis de Leucocito , Femenino , Humanos , Queratosis/metabolismo , Queratosis/fisiopatología , Masculino , Persona de Mediana Edad , Neutrófilos/fisiología , Psoriasis/fisiopatologíaRESUMEN
We describe an exceptionally rare case of juvenile generalized pustular psoriasis noted in monozygotic twins who, after developing the disease on the same day (the 48th day after birth) continued to show strikingly similar clinical features of generalized pustular psoriasis for 7 years. Not even therapeutic intervention by tonsillectomy performed at age 4 years on one of the twins, which was expected to have some beneficial effect, could decrease the number of attacks or pustulation compared with the counterpart.