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1.
Clin Exp Immunol ; 199(3): 326-336, 2020 03.
Article En | MEDLINE | ID: mdl-31660581

Secretory IgA (SIgA) is a well-known mucosal-surface molecule in first-line defense against extrinsic pathogens and antigens. Its immunomodulatory and pathological roles have also been emphasized, but it is unclear whether it plays a pathological role in lung diseases. In the present study, we aimed to determine the distribution of IgA in idiopathic pulmonary fibrosis (IPF) lungs and whether IgA affects the functions of airway epithelial cells. We performed immunohistochemical analysis of lung sections from patients with IPF and found that mucus accumulated in the airspaces adjacent to the hyperplastic epithelia contained abundant SIgA. This was not true in the lungs of non-IPF subjects. An in-vitro assay revealed that SIgA bound to the surface of A549 cells and significantly promoted production of vascular endothelial growth factor (VEGF), transforming growth factor (TGF)-ß and interleukin (IL)-8, important cytokines in the pathogenesis of IPF. Among the known receptors for IgA, A549 cells expressed high levels of transferrin receptor (TfR)/CD71. Transfection experiments with siRNA targeted against TfR/CD71 followed by stimulation with SIgA suggested that TfR/CD71 may be at least partially involved in the SIgA-induced cytokine production by A549 cells. These phenomena were specific for SIgA, distinct from IgG. SIgA may modulate the progression of IPF by enhancing synthesis of VEGF, TGF-ß and IL-8.


Idiopathic Pulmonary Fibrosis/immunology , Immunoglobulin A, Secretory/immunology , Interleukin-8/immunology , Lung/immunology , Transforming Growth Factor beta/immunology , Vascular Endothelial Growth Factor A/immunology , A549 Cells , Aged , Aged, 80 and over , Antigens, CD/genetics , Antigens, CD/immunology , Antigens, CD/metabolism , Epithelial Cells/drug effects , Epithelial Cells/immunology , Epithelial Cells/metabolism , Female , Gene Expression Regulation, Neoplastic/drug effects , Gene Expression Regulation, Neoplastic/immunology , Humans , Idiopathic Pulmonary Fibrosis/metabolism , Idiopathic Pulmonary Fibrosis/pathology , Immunoglobulin A, Secretory/metabolism , Immunoglobulin A, Secretory/pharmacology , Interleukin-8/genetics , Interleukin-8/metabolism , Lung/drug effects , Lung/metabolism , Male , Middle Aged , RNA Interference , Receptors, Transferrin/genetics , Receptors, Transferrin/immunology , Receptors, Transferrin/metabolism , Transforming Growth Factor beta/genetics , Transforming Growth Factor beta/metabolism , Vascular Endothelial Growth Factor A/genetics , Vascular Endothelial Growth Factor A/metabolism
2.
Article En | MEDLINE | ID: mdl-27642646

Activation of PKB/AKT signaling, which requires PDK1 and PDK2 function, drives Vestibular Schwannoma (VS) and meningioma growth. PDK2 function is defined as a molecule that phosphorylates AKT-Ser473. Integrin-Linked Kinase (ILK) functions as PDK2 in PKB/AKT activation in many cancers; therefore, we hypothesized that OSU-T315, a small molecule ILK inhibitor, will inhibit the ILK-PDK2 function in PKB/AKT signaling activation in VS and meningioma cell growth. OSU-T315 decreased cell viability at IC50 < 2µM in VS (HEI193) and meningioma (Ben-Men-1) cell lines, in primary cells at < 3.5µM, while in normal primary Schwann cells at 7.1µM. OSU-T315 inhibits AKT signaling by decreasing phosphorylation at AKT-Ser473, AKT-Thr308, ILK-Ser246 and ILK-Thr173. In addition, OSU-T315 affected the phosphorylation or expression levels of AKT downstream proliferation effectors as well as autophagy markers. Flow cytometry shows that OSU-T315 increased the percentage of cells arrested at G2/M for both, HEI193 (39.99%) and Ben-Men-1 (26.96%) cells, compared to controls (21.54%, 8.47%). Two hours of OSU-T315 treatment increased cell death in both cell lines (34.3%, 9.1%) versus untreated (12.1%, 8.1%). Though longer exposure increased cell death in Ben-Men-1, TUNEL assays showed that OSU-T315 does not induce apoptosis. OSU-T315 was primarily cytotoxic for HEI193 and Ben-Men-1 inducing a dysregulated autophagy. Our studies suggest that OSU-T315 has translational potential as a chemotherapeutic agent against VS and meningioma.

3.
Arq. Inst. Biol. (Online) ; 77(3): 497-504, jul.-set. 2010. tab, graf
Article Pt | VETINDEX, LILACS | ID: biblio-1391666

O objetivo do trabalho foi determinar o momento ideal da aplicação dos fungicidas de ação preventiva, (Opera + Assist)* e (PrioriXtra + Nimbus)*, baseado na detecção inicial de primeiros esporos associado às condições ambientais, monitoramento climático e monitoramento convencional (após a detecção dos primeiros sintomas), verificando sua eficiência no controle da ferrugem asiática da soja. O trabalho foi desenvolvido na fazenda Escola da Universidade Estadual de Londrina, onde foram instalados coletores de esporos na área para detecção dos primeiros esporos e também se fez anotação das condições climáticas obtidas em estação metereológica. As aplicações foram feitas a 1, 7, 14 e 21 dias após detecção dos primeiros esporos, seguindo o monitoramento climático e monitoramento convencional. Foram avaliadas a porcentagem da área foliar infectada, desfolha e produtividade de grãos. Observou-se uma menor porcentagem de infecção foliar, quando os produtos foram aplicados logo no início da detecção dos primeiros esporos (1, 7 e 14 dias após detecção) e seguindo o monitoramento climático e, apesar do produto (PrioriXtra +Nimbus)* ter apresentado menores porcentagens de infecção foliar e desfolha quando aplicado nos diferentes momentos, observou-se que na produtividade de grãos não houve diferença entre os produtos testados.


The objective of this study was to determine the ideal time for the application of the fungicides of preventive action (Opera + Assist)* and (PrioriXtra + Nimbus)*, based on the initial detection of early spores associated with environmental conditions, climate monitoring and conventional monitoring (after the detection of the first symptoms), verifying their effectiveness in the control of Asian soybean rust. The study was conducted at the Londrina State University Experimental Station, where spore collectors were installed in the area for early detection of spores and the climate conditions were monitored in a climate station. The applications were made at 1, 7, 14 and 21 days after first detection of spores, according to the climate monitoring and conventional monitoring. Evaluations were made of the infected leaf area, defoliation and soybean yield. There was a lower percentage of leaf infection when the products were applied early in the detection of spores (1, 7 and 14 days after detection), and according to the climate monitoring. Moreover, despite that the product (Nimbus + PrioriXtra)* presented lower percentages of infected leaf and defoliation when applied at the different times, it was observed that in the final yield of the crop there was no difference between the products tested.


Glycine max/microbiology , Spores, Fungal , Phakopsora pachyrhizi , Fungicides, Industrial/analysis , Mitosporic Fungi
4.
Arq. Inst. Biol. (Online) ; 77(2): 245-250, abr.-jun. 2010. tab
Article Pt | VETINDEX, LILACS | ID: biblio-1390620

Ainda não há estudos precisos que quantifiquem os prejuízos decorrentes de infecção por oídio e/ou outras doenças foliares, para a maioria das culturas de importância econômica no Brasil. O objetivo foi quantificar as perdas causadas por oídio (Microsphaera diffusa) infectando a cultura da soja em diferentes estádios fenológicos e relacioná-las ao desenvolvimento e produtividade da cultura. O experimento foi desenvolvido em ambiente protegido, e os tratamentos foram testemunha controlada, testemunha sem controle, infecção iniciada em R1 ­ R2, infecção iniciada em R ­ R, infecção iniciada em R ­ R e infecção iniciada em R ­ R. A avaliação foi feita 345.15.25.35.4 semanalmente, considerando a porcentagem da área foliar infectada. Os resultados mostraram que, no tratamento em que houve infecções iniciadas em R1-R2 e R3-R4, a porcentagem de área foliar afetada foi maior (41% e 38%, respectivamente), com consequente menor produtividade (1.186,6 e 1.309,5 kg.ha-1 respectivamente). No tratamento em que a infecção ocorreu em R ­ R, houve 5.35.4 a menor média de área foliar afetada pela doença (24%) e a produtividade teve queda de 26%. Os resultados mostraram que as perdas de produtividade pelo oídio na cultivar Embrapa 48 variaram ao redor de 26 a 50%, e que a recomendação oficial para o início de controle do oídio da soja, quando esta se apresentar entre 40 e 50% de severidade, deve ser questionada e outros trabalhos neste âmbito devem ser desenvolvidos para determinação das perdas ocasionadas por esta doença na cultura.


At present there are no precise studies quantifying the damages caused by powdery mildews and other foliar diseases for the majority of economically important crops in Brazil. The objective of the present study was to quantify the losses caused by powdery mildews (Microsphaera diffusa) in soybeans in different phenological stages, and to correlate them with the development and yield of the crop. The trials was carried out in the greenhouse and the treatments were: controlled check, noncontrolled check, infection initiated at stage R1-R2, infection initiated at stage R3-R4, infection initiated at stage R5.1-R5.2, infection initiated at stage R5.3-R5.4. The evaluation was done weekly considering the percentage of infected leaf area. The results showed that for the infection beginning at stages R1-R2 and R3-R4 the percentage of affected leaf area was higher (41% and 38%), with consequently lower yields (1,200 and 1,240 kg ha-1). When the infection occurred later at stage R5.3-R5.4, a lower affected leaf area (24%) was observed, and the yield decreased 26%. The results showed that the loss of yield by powdery mildew in cultivar Embrapa 48 ranged from around 26 to 50%, and that the official recommendation for the beginning of control of powdery mildew of soybean, where it presents between 40 and 50% of severity, should be questioned, and other work in this area should be undertaken to determine the loss caused by this disease in the crop.


Glycine max/growth & development , Plant Leaves/microbiology , Erysiphe/pathogenicity
5.
Br J Radiol ; 81(969): e228-30, 2008 Sep.
Article En | MEDLINE | ID: mdl-18769010

Amyloidosis is an unusual cause of mediastinal lymphadenopathy. A localized form of amyloidosis manifesting solely in the intrathoracic lymphnode is extremely rare. We describe a case of intrathoracic lymphadenopathy caused by a localized form of amyloidosis. Calcification has been reported in amyloidosis; however, it has been considered as non-specific. In our case, serial CT carried out over a period of 3 years and 3 months showed an unusual and unsynchronized pattern of enlargement and calcification.


Amyloidosis/diagnostic imaging , Calcinosis/diagnostic imaging , Chest Pain/etiology , Lymphatic Diseases/diagnostic imaging , Mediastinal Diseases/diagnostic imaging , Aged , Amyloidosis/complications , Amyloidosis/genetics , Calcinosis/etiology , Humans , Lymph Nodes/diagnostic imaging , Lymphatic Diseases/etiology , Male , Mediastinal Diseases/genetics , Tomography, X-Ray Computed/methods , Treatment Outcome
9.
Kidney Int ; 71(12): 1223-31, 2007 Jun.
Article En | MEDLINE | ID: mdl-17377506

T cells are thought to be involved in the pathogenesis of renal ischemia-reperfusion injury (IRI); however, earlier studies have not found significant T-cell numbers in the kidney following injury. In this study we test the hypothesis that T cells transiently infiltrate the kidney following reperfusion and leave behind T-cell-derived cytokines such as interferons and interleukins, thus triggering an inflammatory reaction. An early rise of infiltrating T cells was coupled with a decrease in both circulating lymphocytes and CD4+ cells of periarterial lymphocyte aggregates. The renal expression of several chemokines was rapidly and markedly increased by ischemia-reperfusion (IR). Sphingosine-1-phosphate type 1 receptor agonists have been shown to protect kidneys from injury. One of these agonists given before IR significantly reduced histologically assessed renal injury, circulating lymphocyte numbers, and renal T-cell infiltration. This pretreatment did not, however, affect the increase in T-cell chemokines but caused an increase in CD4+ cells in the renal lymphatic system. We conclude that T-cell infiltration is an early event after IRI and is mediated by several chemokines. Sphingosine-1-phosphate receptor agonists reduce renal injury and T-cell infiltration in spite of chemokine generation by inhibiting T-cell mobilization from both renal and extra-renal lymphoid tissue.


CD4-Positive T-Lymphocytes/drug effects , Kidney/blood supply , Kidney/immunology , Receptors, Lysosphingolipid/agonists , Reperfusion Injury/immunology , Reperfusion Injury/prevention & control , Animals , CD4-Positive T-Lymphocytes/immunology , Cell Movement/drug effects , Chemokines/metabolism , Fluorescent Antibody Technique , Kidney/pathology , Kidney Pelvis/immunology , Lymphopenia/immunology , Male , Mice , Oxadiazoles/pharmacology , Reperfusion Injury/pathology , Thiophenes/pharmacology
11.
Neurology ; 66(8): 1251-2, 2006 Apr 25.
Article En | MEDLINE | ID: mdl-16636245

The authors report a Japanese patient with hereditary sensory and autonomic neuropathy type 2 (HSAN2) who has a new mutation of the HSN2 gene. The pathologic findings of the patient matched those of Canadian patients. They identified a homozygous 1134-1135 ins T mutation, resulting in a frameshift, and the subsequent premature stop codon at residue 378. These observations support the hypothesis that HSN2 is a causative gene for HSAN2.


Hereditary Sensory and Autonomic Neuropathies/genetics , Nerve Tissue Proteins/genetics , Adult , Asian People/genetics , Canada , Frameshift Mutation , Hereditary Sensory and Autonomic Neuropathies/classification , Hereditary Sensory and Autonomic Neuropathies/pathology , Humans , Intracellular Signaling Peptides and Proteins , Japan , Male , Minor Histocompatibility Antigens , Pedigree , Protein Serine-Threonine Kinases , WNK Lysine-Deficient Protein Kinase 1
12.
Kidney Int ; 69(9): 1601-8, 2006 May.
Article En | MEDLINE | ID: mdl-16572108

The pathogenesis of renal ischemia/reperfusion (I/R) injury involves activating several signal transduction cascade systems in endothelial cells. Sphingosine 1-phospate (S1P) maintains endothelial cell integrity and inhibits lymphocyte egress via the specific S1P(1) receptor, and may play a role in reducing ischemic renal injury. We examined the protective effects of a newly identified S1P(1)-selective agonist, SEW2871, on mouse renal I/R injury. Kidneys were harvested 1-4 days after I/R injury for histopathology, immunofluorescence studies, and quantitative real-time reverse transcriptase-polymerase chain reaction analyses to assess the change in gene expression profiles of inflammation-associated cytokines and adhesion molecules. SEW2871 improved renal function with a 40% reduction in plasma creatinine levels (P<0.01) and a significant reduction in tubular necrosis scores (I/R only: 4.3+/-0.2 vs I/R+SEW2871: 2.5+/-0.4, P<0.05) 24 h after ischemia. These changes were accompanied by 69% reduction in circulating lymphocytes, and 77 and 66% reduction in infiltrating neutrophils and macrophages in renal outer medulla, respectively (all P<0.01). The mRNA abundance of tumor necrotic factor-alpha (TNF-alpha), P-selectin, E-selectin, and intercellular adhesion molecule-1 (ICAM-1) was markedly increased by I/R injury (3.5-, 4.1-, 3.5-, and 4.8-folds, respectively, all P<0.05 vs sham). SEW2871 treatment partially reversed the upregulation of TNF-alpha, P-selectin, and ICAM-1 (47, 59, 54%, respectively, vs I/R control: 100%, all P<0.05). The reduction in protein expression of TNF-alpha, P-selectin, and ICAM-1 was further confirmed with immunofluorescence studies. These results suggest that SEW2871 ameliorates renal I/R injury by inhibiting lymphocyte egress and reducing pro-inflammatory molecules. This new class of renoprotective agent shows promise as a novel approach in preventing/treating ischemic acute renal failure.


Acute Kidney Injury/drug therapy , Ischemia/drug therapy , Kidney/blood supply , Oxadiazoles/therapeutic use , Receptors, Lysosphingolipid/agonists , Reperfusion Injury/prevention & control , Thiophenes/therapeutic use , Acute Kidney Injury/metabolism , Acute Kidney Injury/pathology , Animals , Cell Adhesion Molecules/genetics , Cell Adhesion Molecules/metabolism , Down-Regulation , Ischemia/metabolism , Ischemia/pathology , Kidney/metabolism , Kidney/pathology , Leukocyte Count , Male , Mice , RNA, Messenger/metabolism , Reperfusion Injury/metabolism , Reperfusion Injury/pathology , Tumor Necrosis Factor-alpha/genetics , Tumor Necrosis Factor-alpha/metabolism
13.
Eur J Clin Nutr ; 60(5): 573-9, 2006 May.
Article En | MEDLINE | ID: mdl-16391577

OBJECTIVE: To investigate the effects of short-term folic acid and/or riboflavin supplementation on serum folate and plasma plasma total homocysteine (tHcy) concentrations in young Japanese male subjects. DESIGN: In a double blind, randomized controlled trial. INTERVENTION: Subjects were randomly assigned to one of four groups and received a placebo (control group), 800 microg/day folic acid (FA group), 8.4 mg/day riboflavin (R group), or both (FAR group) for 2 weeks. SETTING: Tokyo, Japan. SUBJECTS: In total, 32 healthy male volunteers aged 20-29 years. RESULTS: At the end of the 2 week supplementation period, the tHcy concentration decreased significantly in the FA group. Serum folate concentrations had increased between 2.7 and 2.0-fold in the FA and FAR groups, respectively, but the mean within-group changes in serum folate and plasma tHcy concentrations did not differ between these two groups. At the end of the study, alanine amino transferase was decreased in the R and FAR groups, while alanine amino transferase was increased in the FA group. CONCLUSION: Supplementation with folic acid, 800 microg/day, for 2 weeks, increased the serum and red blood cell folate concentrations and decreased the plasma tHcy concentrations in healthy young male subjects. Riboflavin supplementation may have blunted the effect of folic acid, which resulted in a diminished reduction of tHcy in our subjects.


Alanine Transaminase/metabolism , Homocysteine/blood , Hyperhomocysteinemia/prevention & control , Vitamin B Complex/administration & dosage , Vitamin B Complex/blood , Adult , Dietary Supplements , Double-Blind Method , Drug Interactions , Erythrocytes/chemistry , Folic Acid/administration & dosage , Folic Acid/blood , Humans , Hyperhomocysteinemia/complications , Male , Riboflavin/administration & dosage , Riboflavin/blood
14.
J Neurochem ; 93(3): 654-63, 2005 May.
Article En | MEDLINE | ID: mdl-15836624

On the basis of the hypothesis that the interaction of mutant proteins with expanded polyglutamine stretches with transcriptional co-activator, TAFII130, leads to transcriptional dysregulation, the transcriptional activation of c-Fos and its suppression by expanded polyglutamine stretches was investigated. The phosphorylation of cAMP-responsive element binding protein (CREB) and induction of c-Fos in response to cAMP were strongly suppressed in Neuro2a cells expressing expanded polyglutamine. The suppression of CREB-dependent transcriptional activation was reversibly rescued by increasing the concentration of cAMP. Expanded polyglutamine-induced cytotoxicity was also substantially suppressed by augmenting CREB-dependent transcriptional activation with a high concentration of cAMP. FR901228, a histone deacetylase inhibitor, was also demonstrated as rescuing the expanded polyglutamine-induced suppression of CREB phosphorylation and c-Fos expression. Furthermore, nuclear fragmentation was significantly suppressed by FR901228. The co-expression of dominant-negative CREB vectors considerably abrogated the suppressive effect of cAMP and FR901228 on the expanded polyglutamine-induced nuclear fragmentation, suggesting that these compounds suppress polyglutamine-induced cytotoxicity, largely, via the enhancement of CREB-dependent transcriptional activation. These findings suggest that the interference of CREB-dependent transcriptional activation by expanded polyglutamine stretches is involved in the pathogenetic mechanisms underlying neurodegeneration, and that the augmentation of CREB-dependent transcriptional activation is a potential strategy in treating polyglutamine diseases.


Cyclic AMP Response Element-Binding Protein/biosynthesis , Neurodegenerative Diseases/metabolism , Peptides/metabolism , Transcriptional Activation/physiology , Animals , COS Cells , Chlorocebus aethiops , Cyclic AMP Response Element-Binding Protein/genetics , Depsipeptides/pharmacology , Genetic Therapy/methods , Mice , Neurodegenerative Diseases/genetics , Neurodegenerative Diseases/therapy , Peptides/genetics , Transcriptional Activation/drug effects
15.
Exp Dermatol ; 14(1): 34-40, 2005 Jan.
Article En | MEDLINE | ID: mdl-15660917

In order to investigate the mechanism of glycolic acid (GA) function in human stratum corneum, we monitored changes in cathepsin D-like (CD) and chymotrypsin-like (SCCE) proteinases for 3 weeks following topical GA application (50% w/v, pH 0.9) for 30 min to human skin. In the early phase, weakened stratum corneum cohesion in the lower layers was observed on day 2 and the amount of active CD in the upper layer of the stratum corneum was significantly decreased from 30 min until day 2, whereas that in the lower layer remained normal. In contrast, the amount of active SCCE showed no change during the experimental period. The surface pH of the stratum corneum drastically decreased to pH 2 at 30 min and slightly recovered to around pH 3 until 1 day after treatment. From 9 to 19 days, a decrease in corneocyte cell area and a remarkable long-term increase in the amount of active CD in the upper layer were observed. In an in vitro study, the activities of desquamation-regulating proteinases were shown to have remarkably increased at around pH 3, due to activation of CD at its optimal pH. These results suggest that GA functions via at least two different mechanisms, acute activation of CD in the lower layer by acidification around pH 3, along with inactivation of CD in the upper layer, and long-term enhancement of de novo CD production in the few weeks following GA treatment.


Epidermis/drug effects , Glycolates/pharmacology , Keratolytic Agents/pharmacology , Administration, Cutaneous , Adult , Cathepsin D/metabolism , Chymases , Epidermis/enzymology , Epidermis/pathology , Female , Glycolates/administration & dosage , Humans , Hydrogen-Ion Concentration/drug effects , Keratolytic Agents/administration & dosage , Male , Middle Aged , Peptide Hydrolases/chemistry , Peptide Hydrolases/metabolism , Serine Endopeptidases/metabolism , Time Factors , Water/metabolism
16.
Kyobu Geka ; 57(13): 1241-4, 2004 Dec.
Article Ja | MEDLINE | ID: mdl-15609666

A 67-year-old female was referred to our hospital because of bronchoesophageal fistula detected by upper gastro-intestinal series for cancer screening. The patient has had a history of coughing on liquid ingestion since childhood and she has been hospitalized 4 times for treatment of pneumonia during the past 20 years. While waiting the treatment, she was emergently admitted to the hospital because of massive hemoptysis. Transcatheter embolization of feeding arteries including the right inferior phrenic artery successfully controlled her hemoptysis. After reembolization of the feeding arteries for preventing massive hemorrhage during operation, posterolateral thoracotomy was performed. Surgical findings disclosed the bronchoesophageal fistula without inflammatory changes. She underwent fistulectomy combined resection of the middle and lower lobes which were destroyed by the repeated pneumonia. This case was considered type I congenital bronchoesophageal fistula according to Braimbridge and Keith classification because of the presence of diverticular projection which connected to the bronchus. Early diagnosis and rapid treatment are thought to be important for treating this disease.


Bronchial Fistula/congenital , Esophageal Fistula/congenital , Hemoptysis/etiology , Aged , Bronchial Fistula/complications , Bronchial Fistula/surgery , Esophageal Fistula/complications , Esophageal Fistula/surgery , Female , Humans
17.
Br J Dermatol ; 151(2): 355-61, 2004 Aug.
Article En | MEDLINE | ID: mdl-15327542

BACKGROUND: We previously reported that an ambient aspartic proteinase is crucial to desquamation of the stratum corneum at pH 5. Identification of this aspartic proteinase by using enzyme inhibitors suggested it to be cathepsin D, although we could not exclude cathepsin E. OBJECTIVES: To determine the identity of this aspartic proteinase and its distribution within the stratum corneum. METHODS: We measured enzyme activities of cathepsin D and cathepsin E in the salt and detergent extracts from callus stratum corneum, using a fluorogenic peptide as a substrate and comparing the effect of addition of Ascaris pepsin inhibitor (specific for cathepsin E) with that of pepstatin A (which inhibits both cathepsin D and cathepsin E). Both enzymes were then extracted and purified from plantar stratum corneum samples and identified by Western blotting. Immunofluorescence microscopy was used to investigate the localization of proteinases within human plantar stratum corneum sample sections. RESULTS: We found that 20% of total aspartic proteinase activity could be attributed to cathepsin E, the remainder to cathepsin D. Two subunits of cathepsin D were identified, a mature active form at 33 kDa and an intermediate active form at 48 kDa; cathepsin E was also identified at 48 kDa, although in a stained band 10-fold weaker in the immunoblot. Immunofluorescence microscopy showed the antibody to cathepsin D to be localized in the lipid envelopes of the stratum corneum, whereas that to cathepsin E stained the tissue diffusely. The labelling for cathepsin D was similar to that observed for desmosomes, and immunoelectron microscopy confirmed that cathepsin D was present on desmosomes. On the other hand, cathepsin E occurred intracellularly within the squames. CONCLUSIONS: We conclude that cathepsin D, and not cathepsin E, causes desquamation by degrading desmosomes.


Cathepsin D/metabolism , Cathepsin E/metabolism , Desmosomes/metabolism , Epidermis/metabolism , Cathepsin D/isolation & purification , Cathepsin E/isolation & purification , Desmosomes/immunology , Desmosomes/ultrastructure , Epidermis/immunology , Epidermis/ultrastructure , Heel , Humans
18.
Exp Dermatol ; 13(8): 465-71, 2004 Aug.
Article En | MEDLINE | ID: mdl-15265010

Nitric oxide (NO) is a potent intercellular mediator of melanogenesis, whereas metallothionein (MT) is an inducible intracellular antioxidant that has been reported to scavenge NO. We investigated the existence and induction of MT in melanocytes, and its inhibitory effect on NO-induced melanogenesis. The expression of MT was detected in melanocytes, however, at a lower level than in keratinocytes, and its induction was possible by the addition of zinc chloride. Further, an NO-stimulated increase of tyrosinase activity in melanocytes was remarkably suppressed, when MT was induced prior to NO stimulation. Melanogenesis was also suppressed, when dexamethasone was used to induce MT. However, an NO-stimulated increase of tyrosinase expression was not suppressed at the gene and protein level, when MT was induced in melanocytes. The same suppressive effect of melanogenesis was also observed, when alpha-melanocyte-stimulating hormone or endothelin-1 was used as a stimulator. Because these results implied a mechanism other than NO scavenging to explain the suppressive effect of MT induction on melanogenesis, the direct inhibition of tyrosinase by MT was examined. Melanosome fractions were prepared from melanocytes, whose melanogenesis was suppressed by the induction of MT. Tyrosinase suppression was observed in the melanosome fractions, which was neutralized by the addition of anti-MT antibody. These results suggest that MT induction may be effective to suppress melanogenesis stimulated by NO as well as other melanogens, and these suppressive effects might be due to a direct inhibition of tyrosinase activity in melanosome and not a scavenging effect of NO.


Melanocytes/metabolism , Metallothionein/metabolism , Metallothionein/physiology , Blotting, Northern , Blotting, Western , Chlorides/metabolism , Chlorides/pharmacology , Dexamethasone/pharmacology , Endothelin-1/metabolism , Fibroblasts/metabolism , Glucocorticoids/pharmacology , HeLa Cells , Humans , Keratinocytes/metabolism , Melanosomes/metabolism , Monophenol Monooxygenase/metabolism , Nitric Oxide/metabolism , RNA, Messenger/metabolism , Reverse Transcriptase Polymerase Chain Reaction , Time Factors , Zinc Compounds/metabolism , Zinc Compounds/pharmacology , alpha-MSH/metabolism
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