Developmental mucin gene expression in the gastroduodenal tract and accessory digestive glands. I. Stomach. A relationship to gastric carcinoma.

Studies were undertaken to provide information regarding cell-specific expression of mucin genes in stomach and their relation to developmental and neoplastic patterns of epithelial cytodifferentiation. In situ hybridization was used to study mRNA expression of eight mucin genes (MUC1-4, MUC5AC, MUC5B, MUC6, MUC7) in stomach of 13 human embryos and fetuses (8-27 weeks' gestation), comparing these with normal, metaplastic, and neoplastic adult tissues. These investigations have demonstrated that MUC1, MUC4, MUC5AC, MUC5B, and MUC6 are already expressed in the embryonic stomach at 8 weeks of gestation. MUC3 mRNA expression can be observed from 10.5 weeks of gestation. MUC2 is expressed at later stages, concomitant with mucous gland cytodifferentiation. Normal adult stomach is characterized by strong expression of MUC1, MUC5AC, and MUC6, less prominent MUC2, and sporadic MUC3 and MUC4, without MUC5B and MUC7. Intestinal metaplasia is characterized by an intestinal-type pattern with MUC2 and MUC3 mRNA expression. Gastric carcinomas exhibit altered mucin gene expression patterns with disappearance of MUC5AC and MUC6 mRNAs in some tumor glands, abnormal expression of MUC2, and reappearance of MUC5B mRNAs. In conclusion, we have observed that patterns of mucin gene expression in embryonic and fetal stomach could show similarities with some gastric carcinomas in adults. Differences in mucin gene expression in developmental, metaplastic, and neoplastic stomach compared to normal adult stomach suggest a possible regulatory role for their products in gastric epithelial cell proliferation and differentiation.     

The mouse one P-domain (pS2) and two P-domain (mSP) genes exhibit distinct patterns of expression

We have previously shown that the human pS2 gene, which codes for a secreted peptide of 60 amino acids, is expressed in a number of human carcinomas, including carcinomas of the breast, the pancreas, and the large bowel. Strong pS2 gene expression was also observed in the normal gastric mucosa and in the regenerative tissues surrounding ulcerous lesions of the gastrointestinal tract. A number of pS2 similar peptides, designated as P-domain peptides, have been described, notably the porcine (PSP), murine (mSP), and human (hSP) spasmolytic polypeptides, which correspond to duplicated pS2 proteins. We have now cloned a mouse homolog of the human pS2 cDNA to dispose of an animal model to study the pS2 protein function, which remains unknown at the present time. We show that the mouse putative pS2 protein sequence and the physiological pattern of expression of the mouse pS2 gene are well conserved. The mouse pS2 gene is highly expressed in the stomach mucosa cells, whereas no pS2 gene expression could be detected in the mouse mammary gland, even during postnatal development processes dependent on growth factors or hormones. Using in situ hybridization, we show that although coexpressed in the fundus, the antrum and the antrum-pyloric regions of the stomach, the mouse pS2 and mSP genes exhibit distinct and complementary cellular patterns of expression.     

北川山羊PPARD基因克隆及组织表达分析

本试验从北川山羊的乳腺组织得到PPARD基因序列,并对其特有的生物学特点进行分析,同时将其在不同组织中所表达的情况进行阐述。利用RT-PCR的技术克隆获得北川山羊PPARD基因的序列,采用实时荧光定量PCR检测PPARD基因在北川山羊不同组织和泌乳期的表达丰度。结果表明,所得的北川山羊PPARD基因序列的CDs区有1 326 bp(登录号:XM018039044),由441个氨基酸编码,是不稳定的亲水性蛋白,不存在信号肽序列和跨膜结构。PPARD基因在北川山羊的表达水平最高的是脂肪组织,极显著高于其他组织(p<0.01),在乳腺组织和胃中也有较高的表达。其在泌乳早期的表达水平极显著高于空怀期和干奶期,这为进一步研究PPARD基因在北川山羊乳腺脂代谢过程所起的作用提供了理论基础。     

Cloning and expression of xP1-L, a new marker gene for larval surface mucous cells of tadpole stomach in Xenopus laevis

The amphibian gastrointestinal tract is remodeled from a larval-type to an adult-type during metamorphosis. In the present study, we examined the products of subtractive hybridization between tadpole and frog stomach cDNAs of Xenopus laevis in order to identify genes expressed specifically in the larval stomach epithelium. A new gene homologous to xP1 was obtained and named xP1-L. In the genome database of Silurana tropicalis, we found a homologue of xP1-L and named it stP1-L. RT-PCR showed that the expression of xP1-L was detected in stage 41/42 tadpoles. In addition, in situ hybridization showed that xP1-L was localized to surface mucous cells of the larval stomach. The H(+)/K(+)-ATPase beta subunit, a marker gene for manicotto gland cells in the tadpole stomach, was also detected at the same time. However, adult marker genes such as xP1 for surface mucous cells and pepsinogen C (PgC) for oxynticopeptic cells were not expressed in the tadpole stages. The expression of xP1-L gradually decreased towards the metamorphic climax and disappeared after stage 61 when larval-type gastric epithelium is replaced by adult-type. We found that xP1-L was never expressed in surface mucous cells of the adult-type stomach, and xP1, instead of xP1-L, was expressed. During T3-induced metamorphosis, xP1-L expression decreased in the same manner as during natural metamorphosis. Thus, xP1-L is a useful marker for larval surface mucous cells in tadpole stomach. This is the first demonstration of a marker gene specific for the surface mucous cells of the larval stomach.     

Dynamic expression patterns of the new protocadherin families CNRs and Pcdh-gamma during mouse odontogenesis: comparison with reelin expression

Wnt signaling regulates cell fate decisions and cell proliferation during development and in adult tissues in both invertebrates and vertebrates. Here we describe the identification of Wnt genes, Wnt2a, 4, 5a, 5b, 6 and 11, expressed in mouse embryonic gut development. Each of these genes exhibits a characteristic and regional-specific expression pattern along the anterior-posterior axis of the digestive tube between embryonic day (E) 12.5 and 16.5 of embryonic development. The expression of Wnt5a is confined to the mesenchymal compartment, while expression of Wnt4 is found both in the intestinal epithelium and the mesenteric anlage. Wnt11 is expressed in the epithelium of esophagus and colon, but also in mesenchymal cells of the stomach. Wnt5b and Wnt6 exhibit restricted expression in the epithelium of the esophagus. A characteristic regionalized expression pattern is observed in the developing stomach. Wnt5a is expressed in the mesenchymal layer of the prospective gland region but becomes restricted to the tip of the gland region by E14.5. Wnt11 is highly expressed at the gastro-esophageal junctions, while Wnt4 is found in the epithelium lining the pyloric region of the stomach but not in the epithelium of the prospective gland region.     

Cloning and expression of xP1-L,a new marker gene for larval surface mucous cells of tadpole stomach in Xenopus laevis

The amphibian gastrointestinal tract is remodeled from a larval-type to an adult-type during metamorphosis. In the present study, we examined the products of subtractive hybridization between tadpole and frog stomach cDNAs of Xenopus laevis in order to identify genes expressed specifically in the larval stomach epithelium. A new gene homologous to xP1 was obtained and named xP1-L. In the genome database of Silurana tropicalis, we found a homologue of xP1-L and named it stP1-L. RT-PCR showed that the expression of xP1-L was detected in stage 41/42 tadpoles. In addition, in situ hybridization showed that xP1-L was localized to surface mucous cells of the larval stomach. The H⁺/K⁺-ATPase β subunit, a marker gene for manicotto gland cells in the tadpole stomach, was also detected at the same time. However, adult marker genes such as xP1 for surface mucous cells and pepsinogen C (PgC) for oxynticopeptic cells were not expressed in the tadpole stages. The expression of xP1-L gradually decreased towards the metamorphic climax and disappeared after stage 61 when larval-type gastric epithelium is replaced by adult-type. We found that xP1-L was never expressed in surface mucous cells of the adult-type stomach, and xP1, instead of xP1-L, was expressed. During T3-induced metamorphosis, xP1-L expression decreased in the same manner as during natural metamorphosis. Thus, xP1-L is a useful marker for larval surface mucous cells in tadpole stomach. This is the first demonstration of a marker gene specific for the surface mucous cells of the larval stomach.     

BMPs are necessary for stomach gland formation in the chicken embryo: a study using virally induced BMP-2 and Noggin expression

Epithelial-mesenchymal interactions are necessary for the normal development of various digestive organs. In chicken proventriculus (glandular stomach), morphogenesis and differentiation of the epithelium depend upon the inductive signals coming from underlying mesenchyme. However, the nature of such signals is still unclear despite extensive analyses carried out using experimental tissue recombinations. In this study we have examined the possible involvement of bone morphogenetic proteins (BMPs) in the formation of stomach glands in the chicken embryo. Analysis of the expression patterns of BMP-2, -4 and -7 showed that these BMPs were present in the proventricular mesenchyme prior to the initiation of the proventricular gland formation. BMP-2 expression, in particular, was restricted to the proventriculus among anterior digestive organs. Virus-mediated BMP-2 overexpression resulted in an increase in the number of glands formed. Moreover, ectopic expression of Noggin, which antagonizes the effect of BMPs, in the proventricular mesenchyme or epithelium, led to the complete inhibition of gland formation, indicating that BMP signals are necessary for the proventricular gland formation. These findings suggest that BMPs are of prime importance as mesenchymal signals for inducing proventricular glands.     

Expression patterns of human DAB2IP protein in fetal tissues

Human DOC-2/DAB2-interacting protein (DAB2IP) is encoded by a tumor suppressor gene and a newly recognized member of the Ras-GTPase-activating family. DAB2IP is a critical component of many signal transduction pathways mediated by Ras and tumor necrosis factors including apoptosis pathways, and it is involved in the formation of many types of tumors. DAB2IP participates in regulation of gene expression and pluripotency of cells. It has been reported that DAB2IP was expressed in different tumor tissues. Little information is available concerning the expression levels of DAB2IP in normal tissues and cells, however, and no studies of its expression patterns during the development of human embryos have been reported. We examined the expression of DAB2IP during human embryonic development to understand better DAB2IP functions. Human fetuses, weeks 9 to 38, and a newborn were obtained from miscarriages or stillbirths. Tissues were embedded in paraffin to construct arrays that were stained immunohistochemically. The DAB2IP-positive cells were identified and scored based on both the percentage of stained cells and their staining intensities. DAB2IP was expressed in most fetal tissues examined. DAB2IP was expressed primarily in cell cytoplasm throughout the fetal development. The expression levels varied among tissues and different gestational ages. Virtually no expression was observed in the cerebrum, parotid gland, thymus, thyroid gland and spleen. Expression was much greater in the adrenal gland and pancreas; weakly to moderately strong in the endocardium, stomach, kidney, testis and small intestine; and lower in liver, trachea, skin, ovary and endometrium. Its expression in the lung, esophagus and bladder were much weaker to absent.     

Developmentally regulated expression of the murine ortholog of the potassium channel KIR4.2 (KCNJ15)

The gene KIR4.2 (K(+) inwardly rectifying channel 4.2) has been recently identified in the Down syndrome Chromosome Region 1. We have cloned the mouse ortholog of KIR4.2 and characterized its expression pattern. In situ hybridization showed a restricted and developmentally regulated pattern of expression. The expression is starting at E12.5 and expands at E14.5 in different tissues and organs, which may be affected in Down syndrome: heart, thymus, thyroid gland, and perichondrium. At E17.5, additional epithelia (kidney, bladder, stomach, lung) expressed also strongly the gene.     

Stomach remodeling-associated changes of H+/K+-ATPase beta subunit expression in Xenopus laevis and H+/K+-ATPase-dependent acid secretion in tadpole stomach

Through subtractive hybridization, H+/K+-ATPase beta subunit mRNA, highly expressed in the larval stomach of Xenopus laevis, was isolated. In situ hybridization demonstrated that the H+/K+-ATPase beta subunit mRNA was exclusively expressed in manicotto gland cells of the larval stomach, not in any other cell. Northern blot analysis showed that metamorphosis-associated changes of the H+/K+-ATPase beta subunit mRNA expression in the stomach were characterized by high expression in tadpoles, a considerably lower expression in metamorphosing tadpoles, and a re-increase of expression in froglets. Further in situ hybridization showed that the decrease of expression correlated with the degeneration of larval type epithelium in the manicotto gland, while the re-increase correlated with the differentiation of oxynticopeptic cells of the adult type stomach. Moreover, the H+/K+-ATPase beta subunit mRNA was expressed in adult epithelial primordia. Such changes were found in thyroid hormone-induced precocious metamorphosis. Based on studies using this ATPase as well as xP1 and PgC (pepsinogen C) as molecular markers, this study discusses a probable cell lineage involved in metamorphosis-associated stomach remodeling. The pH of luminal contents of the larval stomach was found to be lower than 2. In addition, the pH of an isolated stomach changed from 7.2 to lower than 4 after incubation in Ringer's solution, suggesting acid production from the larval stomach. This is the first demonstration of the H+/K+-ATPase-mediated acid production and secretion in the larval stomach of Xenopus laevis.     

Expression patterns of human DAB2IP protein in fetal tissues

Abstract

Human DOC-2/DAB2-interacting protein (DAB2IP) is encoded by a tumor suppressor gene and a newly recognized member of the Ras-GTPase-activating family. DAB2IP is a critical component of many signal transduction pathways mediated by Ras and tumor necrosis factors including apoptosis pathways, and it is involved in the formation of many types of tumors. DAB2IP participates in regulation of gene expression and pluripotency of cells. It has been reported that DAB2IP was expressed in different tumor tissues. Little information is available concerning the expression levels of DAB2IP in normal tissues and cells, however, and no studies of its expression patterns during the development of human embryos have been reported. We examined the expression of DAB2IP during human embryonic development to understand better DAB2IP functions. Human fetuses, weeks 9 to 38, and a newborn were obtained from miscarriages or stillbirths. Tissues were embedded in paraffin to construct arrays that were stained immunohistochemically. The DAB2IP-positive cells were identified and scored based on both the percentage of stained cells and their staining intensities. DAB2IP was expressed in most fetal tissues examined. DAB2IP was expressed primarily in cell cytoplasm throughout the fetal development. The expression levels varied among tissues and different gestational ages. Virtually no expression was observed in the cerebrum, parotid gland, thymus, thyroid gland and spleen. Expression was much greater in the adrenal gland and pancreas; weakly to moderately strong in the endocardium, stomach, kidney, testis and small intestine; and lower in liver, trachea, skin, ovary and endometrium. Its expression in the lung, esophagus and bladder were much weaker to absent.     

Ontogenetic expression of chromogranin A and its derived peptides, WE-14 and pancreastatin, in the rat neuroendocrine system

 The ontogenetic expression of chromogranin A (CgA) and its derived peptides, WE-14 and pancreastatin (PST), was studied in the rat neuroendocrine system employing immunohistochemical analysis of fetal and neonatal specimens from 12.5-day embryos (E12.5), to 42-day postnatal (P42) rats. CgA immunostaining was first detected in endocrine cells of the pancreas, stomach, intestine, adrenal gland and thyroid at E13.5, E14.5, E15.5, E15.5 and E18.5, respectively. PST-like immunoreactivity was detected in endocrine cells of the pancreas at E13.5, stomach, intestine at E15.5, adrenal gland at E17.5 and thyroid at E18.5. WE-14 immunoreactivity was first observed in the immature pancreas at E15.5, mucosal cells of the stomach at E15.5, scattered chromaffin cells in the immature adrenal gland and mucosal cells of the intestine at E17.5 and thyroid parafollicular cells at E18.5. These data confirm that the translation of the CgA gene is regulated differentially in various neuroendocrine tissues and, moreover, suggests that the posttranslational processing of the molecule is developmentally controlled. Accepted: 18 October 1996     

健胃益气汤对大鼠胃粘膜急性损伤的细胞保护作用

目的建立无水乙醇致大鼠胃粘膜损伤试验模型,研究预先给予健胃益气汤(GWYQT)对急性胃粘膜损伤的细胞保护作用。为临床推广应用该方治疗胃粘膜损伤提供科学理论和实验依据。方法①动物分组、建立动物模型。②取大鼠胃腺区组织制作切片并作HE及PAS染色,光学显微镜观察胃粘膜组织的病理变化。③用免疫组织化学ABC法对大鼠胃粘膜组织细胞凋亡相关蛋白Bcl-2、Bax等进行检测并通过图像分析对以上结果做定性、定位、定量分析及统计学处理。结果健胃益气汤预防用药能维护胃粘膜粘液含量及厚度,降低胃粘膜组织细胞Bax蛋白表达,增加Bcl-2蛋白表达,实验对照组与中药组比较,有显著性差异(P<0.01)。结论给予中药健胃益气汤可有效保护胃粘膜,减轻胃粘膜细胞损伤,抑制细胞凋亡。     

Increased gene expression of endothelin-1 and vasoactive intestinal contractor/endothelin-2 in the mammary gland of lactating mice

In an attempt to understand the roles of endothelin-1 (ET-1) and vasoactive intestinal contractor/endothelin-2 (VIC/ET-2), we have studied the genes for both peptides to be expressed in the mammary gland of lactating mice. We observed through real-time PCR analysis that ET-1 and VIC/ET-2 gene expression gradually increase after parturition and that ET-1 gene expression is significantly higher than that of VIC/ET-2. The distribution of ET-1 peptide was found to be localized mainly in the epithelial cells of the mammary gland at 14th day of lactation. ET-1 gene expression increases significantly, parallel to the increase in beta-casein gene expression, in epithelial cell lines (HC11) of mouse mammary gland after hormonal stimulation by addition of dexamethazone and prolactin. The observed increase in ET-1 expression in differentiated epithelial cells suggests physiological roles for ET-1, including milk production and secretion in the mammary gland of lactating mice.     

Structure and expression of the human MDR (P-glycoprotein) gene family.

The human MDR (P-glycoprotein) gene family is known to include two members, MDR1 and MDR2. The product of the MDR1 gene, which is responsible for resistance to different cytotoxic drugs (multidrug resistance), appears to serve as an energy-dependent efflux pump for various lipophilic compounds. The function of the MDR2 gene remains unknown. We have examined the structure of the human MDR gene family by Southern hybridization of DNA from different multidrug-resistant cell lines with subfragments of MDR1 cDNA and by cloning and sequencing of genomic fragments. We have found no evidence for any other cross-hybridizing MDR genes. The sequence of two exons of the MDR2 gene was determined from genomic clones. Hybridization with single-exon probes showed that the human MDR1 gene is closely related to two genes in mouse and hamster DNA, whereas MDR2 corresponds to one rodent gene. The human MDR locus was mapped by field-inversion gel electrophoresis, and both MDR genes were found to be linked within 330 kilobases. The expression patterns of the human MDR genes were examined by enzymatic amplification of cDNA. In multidrug-resistant cell lines, increased expression of MDR1 mRNA was paralleled by a smaller increase in the levels of MDR2 mRNA. In normal human tissues, MDR2 was coexpressed with MDR1 in the liver, kidney, adrenal gland, and spleen. MDR1 expression was also detected in colon, lung, stomach, esophagus, muscle, breast, and bladder.     

The enhancer domain of the human cytomegalovirus major immediate-early promoter determines cell type-specific expression in transgenic mice.

The human cytomegalovirus (HCMV) major immediate-early promoter (MIEP) is one of the first promoters to activate upon infection. To examine HCMV MIEP tissue-specific expression, transgenic mice were established containing the lacZ gene regulated by the MIEP (nucleotides -670 to +54). In the transgenic mice, lacZ expression was demonstrated in 19 of 29 tissues tested by histochemical and immunochemical analyses. These tissues included brain, eye, spinal cord, esophagus, stomach, pancreas, kidney, bladder, testis, ovary, spleen, salivary gland, thymus, bone marrow, skin, cartilage, and cardiac, striated and smooth muscles. Although expression was observed in multiple organs, promoter activity was restricted to specific cell types. The cell types which demonstrated HCMV MIEP expression included retinal cells of the eye, ductile cells of the salivary gland, exocrine cells of the pancreas, mucosal cells of the stomach and intestine, neuronal cells of the brain, muscle fibers, thecal cells of the corpus luteum, and Leydig and sperm cells of the testis. These observations indicate that the HCMV MIEP is not a pan-specific promoter and that the majority of expressing tissues correlate with tissues naturally infected by the virus in the human host.