Eiko Hidaka

ASC, a novel 22-kDa protein, aggregates during apoptosis of human promyelocytic leukemia HL-60 cells

The cytoskeletal and/or nuclear matrix molecules responsible for morphological changes associated with apoptosis were identified using monoclonal antibodies (mAbs). We developed mAbs against Triton X-100-insoluble components of HL-60 cells pretreated with all-trans retinoic acid. In particular, one mAb recognized a 22-kDa protein that exhibited intriguing behavior by forming an aggregate and appearing as a speck during apoptosis induced by retinoic acid and other anti-tumor drugs. Cloning and sequencing of its cDNA revealed that this protein comprises 195 amino acids and that its C-terminal half has a caspaserecruitment domain (CARD) motif, characteristic of numerous proteins involved in apoptotic signaling. We referred to this protein as ASC (apoptosis-associatedspeck-like protein containing a CARD). TheASC gene was mapped on chromosome 16p11.2–12. The antisense oligonucleotides of ASC were found to reduce the expression of ASC, and consequently, etoposide-mediated apoptosis of HL-60 cells was suppressed. Our results indicate that ASC is a novel member of the CARD-containing adaptor protein family.

A new view of the so-called adenoma malignum of the uterine cervix

Abstract Adenoma malignum of the uterine cervix (mucinous type of minimal deviation adenocarcinoma, mucinous MDA), is a unique neoplasm that is difficult to diagnose owing to the deceptively benign appearance of the tumour cells. The present study was undertaken to explore the phenotypic expression of this tumour compared with those of non-neoplastic cervical tissues and of cervical carcinomas of various types. Ten cases of mucinous MDA, 50 cases with non-neoplastic cervical tissues, 13 of cervical adenocarcinoma including the mucinous (endocervical or intestinal type) and endometrioid types, and 2 of mucoepidermoid carcinoma were examined by various histochemical staining methods, including those for gastric mucins, pepsinogen, lysozyme, chromogranin A and carcinoembryonic antigen. The results revealed that mucinous MDA characteristically exhibited gastric phenotypes. The presence of gastric metaplasia was also demonstrated in 9 cases of mucinous MDA and in 5 of the other cases examined. The 7 endocervical-type adenocarcinomas also included 4 that expressed gastric phenotypes, and 2 of the 3 intestinal-type adenocarcinomas showed the same properties focally. These results indicate the presence of a group of lesions expressing gastric phenotypes in the uterine cervix and suggest a close relationship between these lesions. Cervical adenocarcinomas expressing gastric phenotypes are probably derived from MDA.

Expression of Apoptosis-associated Speck-like Protein Containing a Caspase Recruitment Domain, a Pyrin N-terminal Homology Domain-containing Protein, in Normal Human Tissues

Apoptosis-associated speck-like protein containing a caspase recruitment domain (ASC) is a pyrin N-terminal homology domain (PYD)- and caspase recruitment domain (CARD)-containing a proapoptotic molecule. This molecule has also been identified as a target of methylation-induced silencing (TMS)-1. We cloned the ASC cDNA by immunoscreening using an anti-ASC monoclonal antibody. In this study, we determined the binding site of the anti-ASC monoclonal antibody on ASC and analyzed the expression of ASC in normal human tissues. ASC expression was observed in anterior horn cells of the spinal cord, trophoblasts of the placental villi, tubule epithelium of the kidney, seminiferous tubules and Leydig cells of the testis, hepatocytes and interlobular bile ducts of the liver, squamous epithelial cells of the tonsil and skin, hair follicle, sebaceous and eccrine glands of the skin, and peripheral blood leukocytes. In the colon, ASC was detected in mature epithelial cells facing the luminal side rather than immature cells located deeper in the crypts. These observations indicate that high levels of ASC are abundantly expressed in epithelial cells and leukocytes, which are involved in host defense against external pathogens and in well-differentiated cells, the proliferation of which is regulated.

Helicobacter pylori and two ultrastructurally distinct layers of gastric mucous cell mucins in the surface mucous gel layer

BACKGROUND AND AIMS Helicobacter pylori locate not only on the apical surface of surface mucous cells but also in the mucous gel layer covering the gastric mucosa. The present study was undertaken to observe the mucous gel layer itself and any H pylori in this layer at the electron microscopic level, and to determine whether H pylori proliferate in this layer. METHODS We examined resected human stomachs (five cases, fixed in Carnoys solution, paraffin embedded) under the light microscope, and gastric biopsy specimens (10 cases, fixed in glutaraldehyde with or without osmium, epoxy embedded) under the electron microscope. We performed histochemical staining for gastric mucins and immunostaining forH pylori, gastric gland mucous type mucins, and intestinal mucins. RESULTS Under the electron microscope, surface mucous cell type mucins and gland mucous cell type mucins in the mucous gel layer covering gastric mucosa without intestinal metaplasia showed reticular and band like structures, respectively. H pylori were frequently found as small aggregates within the mucous gel layer of surface mucous cell type mucins, and H pyloriwithin these aggregates were seen dividing.H pylori were frequently found in the mucous gel layer of the surface mucous cell type mucins along the border with the layer of gland mucous cell mucins. Occasionally, H pylori were trapped by frayed thin threads of the gland mucous cell type mucins. CONCLUSIONS The two types of gastric mucins in the mucous gel layer differ in ultrastructure. H pylori preferentially colonise and form microcolonies within the mucous gel layer of surface mucous cell type mucins. Mucins from gland mucous cells may disturb the movement of H pylori within the mucous gel layer.

Differential Expression of Ribosomal Proteins in Human Normal and Neoplastic Colorectum

Ribosomal proteins are a major component of ribosomes and play critical roles in protein biosynthesis. Recently it has been shown that the ribosomal proteins also function during various cellular processes that are independent of protein biosynthesis therefore called extraribosomal functions. In this study we have, for the first time, determined the expression profile of 12 ribosomal proteins (Sa, S8, S11, S12, S18, S24, L7, L13a, L18, L28, L32, and L35a) in normal epithelia of human colorectal mucosa using immunohistochemistry (IHC) and then compared their expression patterns with those of colorectal cancer. In the normal mucosa, ribosomal proteins were largely associated with the ribosomes of mucosal epithelia, and the expression level of ribosomal proteins, except for S11 and L7 proteins, was markedly increased in associated with maturation of the mucosal cells. On the other hand, these ribosomal proteins were markedly decreased in colorectal cancer compared with the normal mucosa. By contrast, S11 and L7 ribosomal proteins were rarely associated with the ribosomes of colorectal epithlia except immature mucosal cells, whereas their expression levels were significantly enchanced in colorectal cancer cells. In addition, L7 ribosomal protien was detected in the secretory granules of the enterochromaffin cells in the colorectal mucosa and in carcinoma cells expressing chromogranin A. These results indicate that the expression of ribosomal proteins is differentially regulated not only in normal mucosa but also in carcinoma of human colorectum, and suggest an extraribosomal function of L7 ribosomal protein in neuroendocrine function.

Caspy, a Zebrafish Caspase, Activated by ASC Oligomerization Is Required for Pharyngeal Arch Development*

The pyrin domain was identified recently in multiple proteins that are associated with apoptosis and/or inflammation, but the physiological and molecular function of these proteins remain poorly understood. We have identified Caspy and Caspy2, two zebrafish caspases containing N-terminal pyrin domains. Expression of Caspy and Caspy2 induced apoptosis in mammalian cells that were inhibited by general caspase inhibitors. Biochemical analysis revealed that both Caspy and Caspy2 are active caspases, but they exhibit different substrate specificity. Caspy, but not Caspy2, interacted with the zebrafish orthologue of ASC (zAsc), a pyrin- and caspase recruitment domain-containing protein identified previously in mammals. The pyrin domains of both Caspy and zAsc were required for their interaction. Furthermore, zAsc and Caspy co-localized to the “speck” when co-transfected into mammalian cells. Enforced oligomerization of zAsc, but not simple interaction with zAsc, induced specific proteolytic activation of Caspy and enhanced Caspy-dependent apoptosis. Injection of zebrafish embryos with a morpholino antisense oligonucleotide corresponding tocaspy resulted in an “open mouth” phenotype associated with defective formation of the cartilaginous pharyngeal skeleton. These studies suggest that zAsc mediates the activation of Caspy, a caspase that plays an important role in the morphogenesis of the jaw and gill-bearing arches.

Helicobacter heilmannii infection: Clinical, endoscopic and histopathological features in Japanese patients

Gastric biopsy materials of 4074 consecutive Japanese patients undergoing esophagogastroduodenoscopy were reviewed, along with those of 15 patients with Helicobacter heilmannii infection (11, chronic gastritis; four, mucosa‐associated lymphoid tissue (MALT) lymphoma). In four patients with H. heilmannii infection, the materials were examined by transmission electronmicroscopy. Urea breath test (three patients) and antibody test (five patients) were performed in patients with H. heilmannii infection. In two patients with MALT lymphoma, H. heilmannii was eradicated. The prevalence of H. heilmannii was 0.1% in the consecutive series. In chronic gastritis, the gastric mucosa was endoscopically normal (13.3%), had erythema (33.3%), or had erosions (53.3%); histologically, it showed no epithelial change, mild mononuclear cell infiltration, and slight and focal neutrophil infiltration; Helicobacter heilmannii was positive with anti‐H. pylori antibody, and was detected in the mucous gel layer and in foveolae. In MALT lymphoma, the gastric mucosa was coarsely granular with enlarged mucosal folds without ulcers (two cases), with small ulcers (one case), or with multiple erosions (one case). Urea breath test and antibody test were both negative. Eradication of H. heilmannii resulted in remission of MALT lymphoma. Helicobacter heilmannii infection is therefore uncommon in Japanese adults, but is associated with chronic gastritis and gastric MALT lymphoma.

Phenotypic and functional alterations of peripheral blood monocytes in neutrophil-specific granule deficiency

Neutrophil‐specific granule deficiency (SGD) is a rare, congenital disease characterized by atypical neutrophil structure and function, resulting in recurrent bacterial infections from early infancy. Homozygous recessive mutations in the CCAAT/enhancer‐binding protein ɛ (C/EBPɛ) gene were described in two of five SGD patients, indicating loss of C/EBPɛ function as the primary genetic defect in this disease. C/EBPɛ is expressed in murine and human macrophages. Macrophages from the C/EBPɛ‐deficient mice show impaired differentiation, phagocytic activity, and transcription of macrophage‐specific genes. To determine if monocyte/macrophage cells are impacted in SGD, we analyzed phenotypic features of peripheral blood (PB) monocytes in a SGD individual lacking functional C/EBPɛ. Flow cytometric analysis of PB leukocytes revealed aberrant expression of CD45, CD11b, CD14, CD15, and CD16 on cells from the SGD individual. Also, the PB CD14+ cells from this individual, weakly stained for the monocyte‐specific enzyme, nonspecific esterase, and electron microscopic examination, indicated morphologic differences between the SGD cells and those from normal controls. Serum interleukin (IL)‐6 levels in the SGD individual during a severe bacterial infection were lower compared with levels in other non‐SGD individuals with sepsis. In contrast, serum IL‐8 levels were markedly elevated in the SGD individual compared with those of non‐SGD individuals in sepsis. PB CD14+ cells from the SGD individual expressed higher IL‐8 mRNA levels compared with normal controls in response to lipopolysaccharide and interferon‐γ. These phenotypic and functional alterations of PB monocytes in the SGD individual suggest that C/EBPɛ plays a critical role in monocyte/macrophage development of humans and is consistent with observations in the murine system. This study implicates abnormalities in monocytes/macrophages and neutrophils in the onset and development of SGD.

Immunohistochemical Demonstration of α1,4-N-acetylglucosaminyltransferase that Forms GlcNAcα1,4Galβ Residues in Human Gastrointestinal Mucosa

α;1,4-N-acetylglucosaminyltransferase (α4GnT) is a glycosyltransferase that mediates transfer of GlcNAc to βGal residues with α1,4-linkage, forming GlcNAcα1 → 4Galβ→R structures. In normal human tissues, glycoproteins having GlcNAcα1→4Galβ→R structures at non-reducing terminals are exclusively limited to the mucins secreted from glandular mucous cells of gastric mucosa, Brunners gland of duodenum, and accessory gland of pancreaticobiliary tract. Recently, we have isolated a cDNA encoding human α4GnT by expression cloning. Although α4GnT plays a key role in producing this unique glycan in vitro, the actual localization of α4GnT was not determined. In this study we examined the localization of α4GnT in various human tissues, including gastrointestinal mucosa, using a newly developed antibody against human α4GnT. The specificity of the antibody was confirmed by analyses of human gastric adenocarcinoma AGS cells transfected by α4GnT cDNA. Expression of α4GnT was largely associated with the Golgi region of mucous cells that produce the mucous glycoproteins having GlcNAcα1→4Galβ→R, such as the glandular mucous cells of stomach and Brunners gland. An immunoprecipitation experiment disclosed that two distinct mucin proteins, MUC5AC and MUC6 present in gastric mucin, carried the GlcNAcα1→4Galβ→R structures. These results indicate that α4GnT is critical to form the mucous glycoproteins having GlcNAcα1→4Galβ→R on MUC6 and MUC5AC in vivo. (J Histochem Cytochem 49:587–596, 2001)

Prevalence of dementia of Alzheimer type and apolipoprotein E phenotypes in aged patients with Down's syndrome.

We investigated the exact prevalence of dementia of Alzheimer type (DAT) and apolipoprotein E (ApoE) phenotypes in 106 Japanese Down’s syndrome (DS) patients. Among these patients 16 were diagnosed as having DAT. The prevalence of DAT was 0% in the 30- to 39-year-old group, 16% in the 40- to 49-year-old group, and 38% in those over 50 years old. The frequency of the σ4 allele in DS patients with DAT was 18.8%, which was considerably higher than that of nondemented DS patients (4.5%) and Japanese nondemented controls (6.7%). Especially, the frequency of the σ4 allele in DS patients who developed DAT under 50 years was significantly higher (28.6%). DS patients certainly develop DAT at earlier ages but the prevalence of DAT in each group of patients was lower than previously recognized. It is very likely that the ApoE σ4 is a risk factor for DAT even in DS patients with a genetic predisposition to Alzheimer’s disease.