Biomedical subjects

S Futamura

Publications and source records attributed to S Futamura.

8 recordsLinked to original sources

PubMed1996

UVB radiation suppresses the TNF-alpha-induced expression of E-selectin and ICAM-1 on cultured human umbilical vein endothelial cells.

Endothelial cells, which are involved in the development of inflammatory and immune responses, can express various kinds of cell adhesion molecules (CAM) including E-selectin and intercellular adhesion molecules-I (ICAM-I). These cell adhesion molecules and their ligands on leukocytes play an essential role in the control of extravasation of inflammatory cells. Ultraviolet B (UVB) radiation can reach the upper dermis and modulate CAM expressions on vascular endothelial cells (EC). We examined the direct effect of UVB on E-selectin and ICAM-I expression on cultured human umbilical vein endothelial cells (HUVEC) and also examined its effect on these cells induced by tumour necrosis factor-alpha (TNF-alpha), which is a potent CAM-inducer and is released by UVB radiation on the skin. Various doses of UVB were exposed to human umbilical vein endothelial cells (HUVEC) and these expressions were examined by flow cytometric analysis using FACScan; 5, 10 and 25 mJ/cm2 UVB induced neither E-selectin nor ICAM-I expression. Irradiation of HUVEC with UVB 30 min after treatment with TNF-alpha inhibited these expressions. Although the inhibition of E-selectin was observed until 12 h in a dose-dependent manner, ICAM-I expression was almost completely inhibited, even at 5 mJ/cm2 UVB. UVB irradiation before TNF-alpha stimulation showed similar effects to those obtained post-irradiation. This study has demonstrated that UVB can directly down-regulate EC functions, and the results may have implications in action mechanisms of UVB therapy.

Cells, Cultured↗

PubMed1992

Proteins of the cornified envelope.

The cornified envelope of keratinocytes is an insoluble structure formed beneath the plasma membrane at the base of the stratum corneum. It is made by cross-linking precursor proteins by a membrane-associated transglutaminase. Using the cornified envelope of cultured human keratinocytes as the immunogen, we obtained a number of monoclonal antibodies which stained epidermis in a variety of ways. The peripheral staining pattern has been associated with several envelope precursors and this has been confirmed by western blots. A mouse IgM monoclonal antibody directed against epidermal basal cell hemidesmosomes was also discovered. By immunofluorescence, the monoclonal antibody produced a strong linear staining of the basement membrane zone and a polar cap on trypsin-dissociated epidermal basal cells. By immunoelectron microscopy, immunoreactants were present in the attachment plaques of hemidesmosomes on guinea pig esophagus. However, no protein reactive with the antibody was detected. This study suggests that an antigen associated with the basal cell hemidesmosomes may be incorporated in the cornified envelope.

Animals↗

PubMed1990

Studies of the relationship of the 230-kD and 180-kD bullous pemphigoid antigens.

In bullous pemphigoid (BP), autoantibodies from most patients recognize a high molecular weight 230-kD epidermal antigen (Ag) by immunoprecipitation. By Western immunoblotting, 50-70% of sera recognize the high molecular weight Ag, but 30-50% recognize a low molecular weight, 180-kD epidermal Ag. We examined the specificities of affinity-purified antibodies against these Ag. Antibodies specific for the 230- and 180-kD Ag were prepared by immunoaffinity against Ag immobilized on nitrocellulose and released by acid glycine. IgG eluted from the 230-kD Ag band retained its specific binding to the 230-kD Ag by immunoblotting, and bound to the epidermal basement membrane zone (BMZ) by indirect immunofluorescence (IF) and to hemidesmosomes by indirect immunoelectron microscopy (EM). IgG affinity purified by the 180-kD Ag band bound only the 180-kD Ag in immunoblotting, with no cross reaction to the 230-kD Ag, bound the epidermal BMZ by indirect IF, and also bound to hemidesmosomes in immuno-EM. IgG specific for the 230-kD Ag in immunoblotting immunoprecipitated only the 230-kD Ag, with no apparent precipitation of the 180-kD Ag. Surprisingly, IgG specific for the 180-kD Ag precipitated both the 180- and the 230-kD Ag in immunoprecipitation, and the 230-kD Ag band was much more intense than the 180-kD Ag band. This study shows that apparent cross-reactivity between these Ag by BP autoantibodies can only be detected in native conditions by immunoprecipitation, and cannot be demonstrated using denatured Ag in immunoblotting. The two proteins appear to be distinct Ag, closely associated in the epidermal hemidesmosome, but the exact relationship of these Ag to each other may not be clarified until complete structural data become available.

Antibodies↗

PubMed1990

Isolation of a human epidermal cDNA corresponding to the 180-kD autoantigen recognized by bullous pemphigoid and herpes gestationis sera. Immunolocalization of this protein to the hemidesmosome.

Autoantibodies present in the sera of patients with bullous pemphigoid (BP) bind to the basement membrane zone of normal human skin and commonly recognize two epidermal proteins, the BP240 and BP180 antigens. Two BP antigen cDNA clones from a lambda gt11 human keratinocyte library have been identified on the basis of reactivity with a BP serum. The fusion protein (FP) produced by one clone immunoadsorbed autoantibodies, which specifically recognized the BP180 by antigen, showing no cross-reactivity with BP240 by immunoblot analysis. The FP produced by the second clone immunoadsorbed autoantibodies which specifically reacted with the BP240 epidermal antigen. Northern blot analysis demonstrated that the BP180 and BP240 antigens are encoded by distinct RNA transcripts with lengths of 6.0 and 8.5 kb, respectively. Immunoblot analysis of the BP180 lysogen extract identified a 135-kD FP which was recognized by 7 of 16 BP sera and 7 of 8 herpes gestationis sera. A rabbit antiserum prepared against the lysogenic BP180 FP specifically recognized the BP180 antigen from human epidermal extracts by immunoblotting, labeled the BMZ by indirect immunofluorescence, and bound to human epidermal hemidesmosomes by immuno-electron microscopy. These results indicate that the BP180 antigen recognized by BP and herpes gestationis autoantibodies is a unique hemidesmosomal polypeptide, distinguishable from the BP240 antigen.

Animals↗

PubMed1989

The pathogenic effect of IgG4 autoantibodies in endemic pemphigus foliaceus (fogo selvagem).

Endemic pemphigus foliaceus, or fogo selvagem, is an autoimmune blistering skin disease caused by IgG autoantibodies to a desmosome-associated glycoprotein. We studied the IgG subclasses with autoantibody activity in serum from 29 patients with active disease and in the skin lesions of 18 patients by immunofluorescence, using IgG-subclass-specific monoclonal antibodies. The predominant disease autoantibodies present in all patients were of the IgG4 subclass. IgG1 and IgG2 autoantibodies were detected in low titer in the 29 patients: IgG1 in 23 patients and IgG2 in 9. IgG3 autoantibodies were not detected in the serum of any patient. Direct immunofluorescence testing of skin lesions showed a preferential deposition of IgG4 on the keratinocyte surface. The pathogenic effect of IgG4 was demonstrated by the passive transfer of fractions containing IgG4 autoantibodies from the patients to neonatal BALB/c mice. The disease of the patients was reproduced clinically, histologically, and immunologically in these animals. Only IgG4 autoantibodies were detected by direct immunofluorescence, bound to the epidermis in the lesions of the mice, and by immunoelectron microscopy at the keratinocyte surface. IgG4 has previously been reported to be a blocking or protective antibody because it has poor effector functions in vitro, as compared with the other IgG subclasses. The finding that it is the pathogenic autoantibody in fogo selvagem raises the possibility that it may also be important in other autoimmune disease.

Animals↗

PubMed1989

Pemphigus foliaceus antigen: characterization of a keratinocyte envelope associated pool and preparation of a soluble immunoreactive fragment.

In both the endemic and sporadic forms of pemphigus foliaceus (PF), antiepidermal autoantibodies against desmoglein I are present. Desmoglein I is a highly insoluble 160-kD transmembrane glycoprotein of the desmosomal core. The detailed immunochemical characterization of the epitope(s) recognized by the PF autoantibodies is hampered by its large molecular weight and the insolubility of desmoglein I in nondenaturing buffers. This study was designed to identify alternative methods that could yield soluble immunoreactive PF antigen (Ag) from normal human epidermis. The presence of PF Ag in human epidermis and in its soluble or insoluble fractions was monitored by indirect immunofluorescence, immunoadsorption of PF sera, and immunoprecipitation of radiolabeled fractions. The PF Ag from trypsin-resistant, radiolabeled cell envelope preparations was cleaved by papain and immunoprecipitated by PF sera. A 50-kD peptide, isoelectric at pH 5.5-5.8, was immunoprecipitated by sera from all patients with endemic PF (n = 15) or idiopathic PF (n = 4), and by two of four pemphigus vulgaris sera, but by no control sera (n = 7). This study shows that a significant fraction of the PF Ag is insoluble, trypsin-resistant, and is associated with the cornified cell envelope fraction, but an Ag fragment can be obtained in a small molecular weight, soluble, and immunoreactive form by papain digestion. This 50-kD papain fragment is more amenable to detailed chemical and immunologic characterization than the native molecule.

Antigens↗

PubMed1989

Ultrastructural studies of acantholysis induced in vivo by passive transfer of IgG from endemic pemphigus foliaceus (Fogo Selvagem).

Intraperitoneal (IP) injections of IgG from patients with Endemic Pemphigus Foliaceus [Fogo Selvagem (FS)] cause acantholysis in BALB/c mice (JID. 85:538, 1985). The dynamic ultrastructural changes of FS IgG-induced acantholysis in mice are the subject of this study. FS IgG was injected IP into neonatal BALB/c mice. Skin and serum was studied at 0, 1, 3, 6, 12, 18, and 24 h post injection by immunofluorescence (IF), electron microscopy (EM), and immuno-EM. Binding of FS IgG in the intercellular spaces (ICS) of the basal cell layer was seen by IF within 1 h and was strongest at 12 h. IgG binding affected the spinous and granular cell layer by 12 h, then faded and remain localized only in the basal cell layer at 24 h. By immuno-EM, IgG binding was diffuse along the keratinocyte surface. Edema of the ICS in the basal cell layer was present at 1 h by EM. At 12 h, there was microvillous formation with intact desmosomes at the tip of the projections. Splitting of desmosomes (forming half desmosomes) and acantholysis primarily affecting the granular cell layer were most prominent between 12 and 24 h. The plaques of the half desmosomes gradually disappeared and tonofilaments retracted into the cytoplasm. Detaching keratinocytes showed vacuolization, swollen mitochondria, and internalization of intact desmosomes and half desmosomes (remnants of split desmosomes). This investigation shows that the ultrastructural changes observed in the epidermis of patients with FS can be duplicated in experimental animals by IP injection of FS IgG. Further, FS IgG may have direct effects on the assembly/disassembly of desmosomes.

Acantholysis↗

PubMed1984

GENAS: a database system for nucleic acid sequence analysis.

A database system, named GENAS (GENe Analyzing System), for computer analysis of sequence was constructed using Adbis which is a relational database management system (1). GENAS enables us to retrieve any sequence data from EMBL nucleotide sequence data library (2) and readily to analyze them (if necessary, together with private data) by various application programs in a interactive manner. Analysis of structure of replication origin of replicons was demonstrated using this system.

Base Sequence↗