Fibulin-2 is involved in early extracellular matrix development of the outgrowing mouse mammary epithelium.

Cell-matrix interactions control outgrowth of mammary epithelium during puberty and pregnancy. We demonstrate here that the glycoprotein fibulin-2 (FBLN2) is strongly associated with pubertal and early pregnant mouse mammary epithelial outgrowth. FBLN2 was specifically localized to the cap cells of the terminal end buds during puberty and to myoepithelial cells during very early pregnancy (days 2-3) even before morphological changes to the epithelium become microscopically visible, but was down-regulated thereafter. Exposure to exogenous oestrogen (E2) or E2 plus progesterone (P) increased Fbln2 mRNA expression in the pubertal gland, indicating hormonal control. FBLN2 was co-expressed and co-localised with the proteoglycan versican (VCAN) and co-localised with laminin (LN), while over-expression of FBLN2 in HC-11 cells increased cell adhesion to several extracellular matrix proteins including LN and fibronectin, but not collagens. Mammary glands from Fbln2 knockout mice showed no obvious phenotype but increased fibulin-1 (FBLN1) staining was detected, suggesting a compensatory mechanism by other fibulin family members. We hypothesise that similar to embryonic aortic smooth muscle development, FBLN2 and VCAN expression alters the cell-matrix interaction to allow mammary ductal outgrowth and development during puberty and to enable epithelial budding during pregnancy.

Characterization of the expression of DMPK and SIX5 in the human eye and implications for pathogenesis in myotonic dystrophy.

The pathogenic mechanisms underlying myotonic dystrophy (DM), which results from a (CTG) n repeat expansion mutation in the 3'-untranslated region (3'-UTR) of the myotonic dystrophy protein kinase gene ( DMPK ), remain obscure. The multisystemic nature and variable expressivity of the symptoms are unlikely to be explained by a defect in this gene alone. However, the location of the DM-associated (CTG) n repeat in the promoter region of SIX5, immediately downstream of DMPK, implicates it as a second candidate with a pathological role in DM. We hypothesize that dysfunction of SIX5, which is homologous to the Drosophila eye development gene sine oculis ( so ), is primarily responsible for the ophthalmic features of DM. We report an expression pattern for SIX5 in the normal adult eye that matches the sites of the ocular pathology in DM. SIX5 transcripts were detected in the adult corneal epithelium and endothelium, lens epithelium, ciliary body epithelia, cellular layers of the retina and the sclera. SIX5 expression was not detected in fetal eyes. We also report a restricted but partially overlapping expression pattern for DMPK transcripts and DMPK protein in normal fetal and adult eyes. DMPK transcripts were detected in fetal eyes and in adult conjunctival and corneal epithelia, uvea, cellular layers of the retina, optic nerve and in the sclera. DMPK protein was detected in the adult retina, conjunctival and ciliary body epithelia and in the smooth muscle of the ciliary body, pupillary sphincter and uveal blood vessels. We propose that the expression patterns of these two genes indicate their relative contribution to the ophthalmological dysfunction seen in DM. Furthermore, the expression of SIX5 and not DMPK in the adult lens implicates a role for SIX5 dysfunction in the development of adult onset cataracts, the most frequently occurring eye phenotype in DM.

Expression of the mucosal vascular addressin, MAdCAM-1, in inflammatory liver disease.

AIMS/BACKGROUND: The integrin alpha4beta7 and mucosal addressin cell adhesion molecule-1 (MAdCAM-1) are involved in normal recirculation of lymphocytes between the blood and the tissues of the gastrointestinal tract. In this study we have examined the expression of MAdCAM-1 in human liver. METHODS: MAdCAM-1 expression was determined in archival human liver tissues by immunohistochemistry. RESULTS: While MAdCAM-1 was not detected in normal fetal or adult human liver, expression was observed in association with portal tract inflammation in a variety of liver diseases. Detailed analysis of liver biopsies from patients with hepatitis C showed a positive correlation between the portal/periportal component of the histological activity index (HAI) grade and the presence or absence of MAdCAM-1 expression. CONCLUSION: MAdCAM-1 expression may be important in the recruitment of lymphocytes to the liver during inflammation.

Effusion cytology of hepatocellular carcinoma with in situ hybridisation for human albumin.

While the cytological features of hepatocellular carcinoma on fine needle aspiration cytology are well described, cases of hepatocellular carcinoma with malignant cells in ascitic fluid and their characteristics are not. A patient is described with cirrhosis resulting from chronic hepatitis B virus infection, ascites, and hepatocellular carcinoma diagnosed by effusion cytology. The malignant cells in the effusion were shown to be positive for alpha fetoprotein using immunocytochemistry, and for human albumin using in situ hybridisation, confirming the diagnosis of hepatocellular carcinoma. Further investigations in a terminally ill patient were thus avoided.

Demonstration of renin gene expression in nephroblastoma by in situ hybridization.

Most patients with nephroblastoma have high levels of plasma renin and some are hypertensive. Blood pressure falls after removal of the affected kidney, suggesting that nephroblastoma is associated with renin production either by the tumour or by the kidney. In this study, direct evidence was sought of renin gene expression in nephroblastoma using in situ hybridization. Digoxigenin-labelled riboprobes and an immunoperoxidase technique were used to detect cells containing renin mRNA: this showed renin gene expression in 9 out of 12 cases. There were positive cells within metanephric blastema and in occasional neoplastic glomeruloid structures, confirming that in seven cases nephroblastoma tumour cells expressed the renin gene. However, renin gene expression was also demonstrated in perivascular cells of uncertain lineage in seven cases; in five cases there was evidence of renin gene expression in both tumour cells and perivascular cells. The latter finding raises the possibility that some of the cells expressing the renin gene could be stromal cells. It is concluded that nephroblastomas contain cells that express the renin gene and that some are tumour cells, while other perivascular cells may be stromal cells.

Hepatocyte proliferation and serum hepatocyte growth factor levels in patients with alcoholic hepatitis.

BACKGROUND/METHODS: Hepatocyte growth factor is thought to be important in stimulating growth of the liver following injury. In this study we have measured serum levels of hepatocyte growth factor together with hepatocyte proliferation in liver biopsies, by detection of the Ki-67 antigen, in 23 patients with alcoholic hepatitis. RESULTS: Serum hepatocyte growth factor was elevated in all patients (median 0.9 ng/ml; range 0.6-7.7 ng/ml; normal < 0.5 ng/ml) and there was a positive correlation between hepatocyte growth factor levels and hepatocyte proliferation in the biopsies. CONCLUSIONS: These results demonstrate that in acute alcoholic hepatitis the liver proliferates in response to injury and suggest that hepatocyte growth factor may be one of the growth factors responsible for this proliferative activity.

The effects of ZENECA ZD8731, an angiotensin II antagonist, on renin expression by juxtaglomerular cells in the rat: comparison of protein and mRNA expression as detected by immunohistochemistry and in situ hybridization.

Changes in the mRNA and protein expression of renin-secreting cells in the juxtaglomerular apparatus (JGA) were examined in the rat following administration of ZENECA ZD8731, an angiotensin II receptor antagonist. Doses of 0 or 90 mg/kg were administered daily by gavage for 26 wk. JGA hypertrophy was apparent in histological sections. Immunohistochemistry demonstrated an increase in the number of renin-containing cells in both the afferent arterioles and the interlobular arteries. Similarly, renin mRNA expression, demonstrated by in situ hybridization, had extended to more proximal segments of the afferent arterioles and was also present in efferent arterioles and interlobular arteries. In conclusion, JGA hypertrophy occurred as a result of antagonism of the angiotensin II receptor. Associated with JGA hypertrophy was increased expression of both renin and renin mRNA, indicative of stimulated renin synthesis caused by an exaggerated pharmacological response of renin-secreting cells to the loss of feedback inhibition by angiotensin II.