Endothelin stimulates transforming growth factor-beta1 and collagen synthesis in stellate cells from control but not cirrhotic rat liver

Interactions between hepatic stellate cells and endothelin-1 are implicated in liver fibrosis. We determined endothelin-1, its receptors and its effects on the synthesis of a fibrogenic agent transforming growth factor (TGF)-beta1 and collagen in stellate cells from control and CCl(4)-induced cirrhotic rats. The basal synthesis of endothelin-1, TGF-beta1 and collagen was much higher in cirrhotic stellate cells than in control cells. Endothelin-1 stimulated TGF-beta1 and collagen synthesis via endothelin ET(A) and endothelin ET(B) receptors, respectively, in control stellate cells, but did not elicit these effects in the cirrhotic cells despite increased density of the respective receptor subtypes in them. These results indicate that the actions of endothelin-1 on stellate cells may be an important physiological mechanism in maintenance of hepatic architecture. However, inability of endothelin-1 to stimulate TGF-beta1 and collagen synthesis in cirrhotic stellate cells suggests that it does not influence fibrogenic activity by direct action on them probably because the processes are already maximally activated.

Inhibitory effects of synthetic beta peptide on invasion and metastasis of liver cancer

PURPOSE

To study the inhibitory effects of synthetic beta peptide on invasion and metastasis of liver cancer.

METHODS

Membrane-type intercellular adhesion molecule-1 (ICAM-1) expression of SMMC-7721 cultured hepatoma cells (7721 cells) was detected by immunofluorescence cell flowmeter. The adhesion of 7721 cells to fibronectin (FN) was assayed by the MTT method. The adhesion of 7721 cells to 7721 cells, 7721 cells to endothelial cells, and 7721 cells to lymphocyte cells was detected by adhesion assay. LCI-D20 human liver cancer metastasis model in nude mice was used in this experiment. One hundred micrograms of beta peptide per mouse were injected subcutaneously after tumor was resected premetastatically or postmetastatically to observe its effect on liver cancer metastasis after hepatectomy.

RESULTS

Membrane-type ICAM-1 expression of SMMC-7721 cells treated by beta peptide was lower than that of the untreated cells. The adhesion of 7721 cells to FN, 7721 cells to 7721 cells, 7721 cells to endothelial cells, and 7721 cells to lymphocyte cells was also lower in the beta peptide group than in the untreated group.

CONCLUSIONS

beta Peptide can block the adhesion of 7721 cells to FN, 7721 cells to some host cells in vitro, and inhibit HCC metastasis of LCI-D20 model posthepatectomy in vivo, so it could potentially act as an antimetastasis drug.

Endotoxin causes up-regulation of endothelin receptors in cultured hepatic stellate cells via nitric oxide-dependent and -independent mechanisms

Hepatic stellate cells (HSC) and their transformed phenotype found in the chronically injured liver play important roles in hepatic physiology and pathology. HSC produce and react to a potent contractile peptide endothelin-1 (ET-1) and also synthesize a vasorelaxant nitric oxide (NO) upon stimulation with endotoxin. However, whether endotoxin affects ET-1 system of HSC and if this is a mechanism of endotoxin-induced hepatic injury is not known. We characterized synthesis of ET-1 and NO and ET-1 receptors in cultured quiescent and transformed HSC subjected to endotoxin treatment. Endotoxin (1 - 1000 ng ml(-1)) stimulated synthesis of ET-1 and NO and up-regulated ET-1 receptors in both cell types. Inhibition of NO synthesis by N(G)-monomethyl-L-homoarginine strongly inhibited endotoxin-induced increase in ET-1 receptors in transformed HSC but produced small additional increase in quiescent HSC. Inhibition of soluble guanylyl cyclase by 1H-[1,2, 4]oxadiazolo[4,3-a]quinoxalin-1-one blocked the effect of endotoxin on ET-1 receptors in both cell types. Moreover, ET-1 receptors were increased in both cell types during earlier time points (1 - 4 h) of endotoxin treatment in the absence of the stimulation of NO synthesis. These results demonstrate that endotoxin up-regulates ET-1 receptors in HSC by NO-dependent and -independent mechanisms. Such effects of endotoxin can be of importance in acute endotoxemia and during chronic injury of the liver.

Flow cytometry for the detection of enterohaemorrhagic Escherichia coli O157:H7 with latex beads sensitized with specific antibody

To detect low concentrations of enterohaemorrhagic Escherichia coli O157:H7 rapidly, flow cytometry (FCM) was carried out with specific IgG-sensitized latex beads (IgG-Lx). It was found that test samples for FCM can be prepared for much shorter periods by culturing E. coli O157:H7 in trypto-soya broth at 42 degrees C and by treatment with 0.5% formalin at 37 degrees C. FCM with IgG-Lx performed with E. coli O157:H7 prepared by such a procedure revealed that the lowest number of E. coli O157:H7 prepared in pure culture detected by FCM was 10(3)/ml. Because similar findings have already been reported by FCM with immunomagnetic beads, FCM with IgG-Lx is also suggested to be a valuable technique to detect low numbers of E. coli O157:H7 rapidly in food stuffs.

Preliminary communication. MRNA expression of MT1-MMP, MMP-9, cathepsin K, and TRAP in highly enriched osteoclasts cultured on several matrix proteins and ivory surfaces

We demonstrated that the transcriptional expression of MT1-MMP, MMP-9, cathepsin K, and TRAP in highly enriched osteoclasts were regulated by different matrix proteins that bind to integrin on osteoclast, such as collagen type I (CoI), fibronectin (FN), vitronectin (VN), osteopontin (OPN), and ivory. Results suggested that the OPN-integrin alphavbeta3 binding plays a more important role than CoI-alpha2beta1 binding in the regulation of osteoclast activity.

Alcohol absorption inhibitors from bay leaf (Laurus nobilis): structure-requirements of sesquiterpenes for the activity

Through a bioassay-guided separation using inhibitory activity on blood ethanol elevation in oral ethanol-loaded rat, various sesquiterpenes having an alpha-methylene-gamma-butyrolactone moiety, costunolide (1), dehydrocostus lactone (2), zaluzanin D (3), reynosin (4), santamarine (5), 3alpha-acetoxyeudesma-1,4(15),11(13)-trien-12,6alpha-+ ++olide (6) and 3-oxoeudesma-1,4,11(13)-trien-12,6alpha-olide (7), were isolated as the active principle from the leaves of Laurus nobilis (bay leaf, laurel). In order to characterize the structure requirement for the activity, several reduction products (2a-2d) and amino acid adducts (2e, 2f) of the alpha-methylene-gamma-butyrolactone moiety were synthesized from 2 and the inhibitory activities of these sesquiterpenes, together with alpha-methylene-gamma-butyrolactone (12) and its related compounds (13-16), were examined. These results indicated that the gamma-butyrolactone or gamma-butyrolactol moiety having alpha-methylene or alpha-methyl group was essential for the inhibitory activity on ethanol absorption. Since 1, 2 and 12 showed no significant effect on glucose absorption, these sesquiterpenes appeared to selectively inhibit ethanol absorption. In addition, the acute toxicities of 1 and 2 in a single oral administration were found to be lower than that of 12.

Patterning of cell assemblies regulated by adhesion receptors of the cadherin superfamily

During morphogenesis, cell-cell association patterns are dynamically altered. We are interested in how cell adhesion molecules can regulate the patterning of cellular assemblies. Cadherins, a group of cell-cell adhesion receptors, are crucial for the organized assembly of many cell types, but they also regulate dynamic aspects of cell association. For example, during neural crest emigration from the neural tube, the cadherin subtypes expressed by crest cells are switched from one subtype to another. Artificial perturbation of this switch results in blocking of their escape from the neural tube. Intracellular modulations of cadherin activity also seem to play a role in regulation of cell adhesion. We identified p120ctn as a regulator of cadherin function in carcinoma cells. With such regulators, cells may make a choice as to whether they should maintain stable cell contacts or disrupt their association. Finally, we found another type of cadherin-mediated cell patterning: Flamingo, a seven-pass transmembrane cadherin, regulates planar cell polarity in Drosophila imaginal discs. Thus, the cadherin superfamily receptors control the patterning of cell assemblies through a variety of mechanisms.

[Malignant solitary fibrous tumor of the pleura: two cases and review of the literature]

We present two cases of malignant solitary fibrous tumor of the pleura (MSFT-P) and review 29 reported cases of MSFT-P. In examining the clinical and morphological features and prognosis of MSFT-P, we found that over 90% of the patients had some symptoms and one-third showed local recurrence. Chest radiographs and CT demonstrated large broad-based masses with necrosis, hemorrhage, and pleural effusion. The maximum diameter of the tumors was greater than 10 cm. Pleural effusion was seen in more than 70% of the patients, but there was only one case of pleural dissemination. All of the cases were well demarcated, and this was the most reliable finding for differentiating MSFT-P and malignant mesothelioma.

Hypergravity effects on osteoclasts activity

The long-term space flight induces a loss of bone density. However, the mechanism has not been well understood, especially about gravity effect on osteoclast. To elucidate the gravitational effect on osteoclasts, we examined the rabbit primary osteoclasts applied to hypergravity and compared the mRNA expression of two kinds of osteoclast marker enzymes, TRAP (tartrate-resistant acid phosphatase) and cathepsin K at the transcription level. Rabbit osteoclasts isolated according to the modified method of Kakudo et al. were cultured on ivory and exposed to 30 x g for 2 hr or 18 hr by placing the culture tubes in a swinging bucket rotor. Results by RT-PCR suggested that hypergravity enhanced the mRNA expression of both enzymes with different manner; the expression of the TRAP showed a smaller increase, that of the cathepsin K showed a non-monotonous time course with maximum hypergravity effect for 2 hr incubation. Moreover we examined the hypergravity effect on actin ring formation in osteoclasts; however, we got no hypergravity effect on the numbers of activated osteoclasts with actin ring formation. These results might suggest that hypergravity has no effect on the number of osteoclasts with resorption activity, but enhances the resorption activity of activated osteoclasts.

Medicinal foodstuffs. XVIII. Phytoestrogens from the aerial part of Petroselinum crispum MIll. (Parsley) and structures of 6"-acetylapiin and a new monoterpene glycoside, petroside

In the course of our screening for natural estrogenic compounds from Occidental medicinal herbs, the extracts of several herbs were found to show proliferative activity in MCF-7 (an estrogen-sensitive breast cancer cell line). Among these active herbs, the methanolic extract from the aerial parts of Petroselinum crispum (parsley) showed potent estrogenic activity, which was equal to that of isoflavone glycosides from soybean. Through bioassay-guided separation, we isolated several flavone glycosides and a new flavone glycoside, 6"-acetylapiin, with estrogenic activity together with a new monoterpene glucoside, petroside. The structures of 6"-acetylapiin and petroside were characterized by the chemical and physicochemical evidence. Estrogenic activities of these flavone glycosides were found to be enhanced by removal of their glycoside moieties. The EC50 values (concentration needed to enhance the MCF-7 proliferation 50% compared to non-estrogen treated cell) of their aglycones are as follows, apigenin (1.0 microM), diosmetin (2.9 microM), and kaempferol (0.56 microM). The estrogenic activities of these flavones are nearly equal to those of the isoflavones, daidzein (0.61 microM) and genistein (0.60 microM). The methanolic extract of parsley, apiin, and apigenin restored the uterus weight in ovariectomized mice when orally administered for consecutive 7 days.

[Antimicrobial susceptibility and serotypes of Streptococcus pneumoniae isolated from the patients with respiratory tract infections in Hokusetsu Area of Osaka]

One hundred and thirteen strains of Streptococcus pneumoniae (S. pneumoniae) were isolated from the clinical specimens of patients with respiratory tract infections between January and December 1998 in three hospitals in Hokusetsu area of Osaka. We investigated susceptibility of 113 strains of S. pneumoniae to benzylpenicillin (PCG) and other antimicrobial agents and their serotypes. 1) Of the 113 strains of S. pneumoniae isolated, 25.7% were susceptible (PSSP), 51.3% were intermediate (PISP) and 23% were resistant to benzylpenicillin (PRSP). 2) The MICs of cefaclor, cefditoren, cefpodoxime, cefdinir, erythromycin, clindamycin and minocycline were elevated, but the MIC values of cefditoren ranged from < or = 0.03 to 1.0 microgram/ml. The susceptibility of 113 strains to cefditoren was comparatively high. 3) The MIC values of imipenem, meropenem and vancomycin for 81 strains of PISP and PRSP ranged from < or = 0.015 to 1.0 microgram/ml, from < or = 0.015 to 2.0 micrograms/ml and from 0.13 to 0.5 microgram/ml, respectively. The susceptibility of these strains to three antimicrobial agents was superior to that to the other antimicrobial agents examined. 4) Of the 60 strains examined, 19, 6, and 23 serotypes were 30, 25 and 18.3%, respectively. The three serotypes were observed in PISP and PRSP with a high frequency. 5) Isolates of S. pneumoniae were 37.2% for children under 2 years of age and 30.9% for children from 2 to 6 years of age. Most of the strains isolated from these children were resistant.

Temporal and spatial localization of novel nuclear protein NP95 in mitotic and meiotic cells

Expression of novel NP95 (nuclear protein, 95 kDa), which contains a leucine zipper motif, a zinc finger motif, a putative cyclin A/E-cyclin-dependent protein kinase 2 phosphorylation site, and retinoblastoma protein-binding motifs, is associated with S-phase progression of mouse cells. It is suppressed during G1 and G2/M phases in normal thymocytes but expressed at a constantly high level irrespective of cell stage in mouse T cell lymphoma cells. NP95 was shown previously to be expressed strongly only in proliferative tissues and cells. In this immunohistochemical study, we demonstrate that NP95 is localized in S-phase nuclei as dot-like foci. Double immunostaining of NP95 and proliferating cell nuclear antigen (PCNA) showed that NP95 was co-localized with PCNA. Construction of three-dimensional images indicated that NP95 was localized with PCNA in replication sites in a somewhat distinct temporal manner. During meiosis, NP95 was present not only in proliferating spermatogonia but also in meiotic spermatocytes and differentiating spermatids which were not proliferating. The possible role of NP95 in mitotic and meiotic cells is discussed.

Purification of L-kynurenine 3-monooxygenase from mitochondrial outer membrane of pig liver

The aim of the present work is to obtain the homogeneous L-kynurenine 3-monooxygenase (Fpk) enzyme preparation by a simple and rapid immunoaffinity purification method. Fpk was purified by monoclonal antibody (mAb) immunoabsorbent column. The column was prepared using hydrazide-activated agarose beads (Affi-Gel Hz) to which IgG molecules were coupled via carbohydrate moieties located on the Fc region and peroxidized with periodate. Partially purified Fpk was charged on the column and after washing the column with buffer containing 0.5 M NaCl and 0.5% Triton-X-100 and then with buffer alone, the enzyme was eluted with acidic elution buffer. Despite the loss of the catalytic activity due to the acidic elution, the immunoaffinity preparation may be useful for the analysis of the chemical structure of Fpk and for the production of the polyclonal antibody toward Fpk.

Pharmacokinetics and biodisposition of fluorescein-labeled arabinogalactan in rats

Fluorescein-labeled arabinogalactan (FA) was prepared by the reaction with FITC in methyl sulphoxide according to the method of deBelder and Granath. A systemic kinetic analysis of FA in rats was carried out by using a specific high-performance size-exclusion chromatography. Intravenously administered FA was rapidly eliminated from the blood circulation followed by an appreciable distribution to the liver and kidney. FA was accumulated in these organs over a long period whereas negligible levels of FA were detected in the other organs. A marked dose-dependency was seen in the hepatic uptake of FA which was markedly reduced by coinjected asialofetuin whereas the renal uptake of FA was not altered. Measurement of the hepatocellular localization demonstrated the overwhelming distribution of FA in the parenchymal liver cell fraction. Furthermore, the microscopic examination revealed FA that was effectively endocytosed by the parenchymal liver cells. These results suggested that FA which is bound to the asialoglycoprotein receptor with a high affinity is subsequently internalized to the hepatocyte via receptor-mediated endocytosis. FA was partially activated by periodate oxidation in order to acquire aldehyde groups to which guest molecules can be bound. A 12.5% oxidized arabinogalactan keeping a hepatocellular targetability showed a good conjugating reactivity to guest molecules via Schiff-base formation or by reductive amination. It was suggested that arabinogalactan can serve as a potential carrier for the delivery of enzymes and drugs to the parenchymal liver cells via the asialoglycoprotein receptor.

Atypical aortic coarctation with resistant hypertension treated with axilloiliac artery bypass

A 68-year-old woman was found to have atypical coarctation of the aorta, accompanied by systolic hypertension of the upper extremities despite administration of five types of antihypertensive drugs. Since the systolic hypertension was resistant to the conventional antihypertensive therapy, axilloiliac artery bypass grafting with a subcutaneous tunnel was performed to alleviate the pressure gradient. Systolic blood pressure was successfully reduced and hypertension was controlled after surgery.

Effects of naloxone on the serum luteinizing hormone level and the number of Fos-positive gonadotropin-releasing hormone neurons in immature female rats

To examine developmental changes in the number of gonadotropin-releasing hormone (GnRH) neurons activated by an opioid receptor antagonist in female rats, blood sampling and double-labeled immunocytochemistry for Fos and GnRH were performed after the injection of naloxone (NAL) in immature (postnatal d16 and d30) and mature female rats. Three age groups of rats were perfused with 4% paraformaldehyde-PB 90 min after the subcutaneous injection of NAL (2.5 mg/kg) or saline. All tissue incubation and staining for double-labeled immunocytochemistry were simultaneously performed. Although no significant developmental change was observed in the total number of GnRH neurons (p0.05), NAL-induced increases in serum luteinizing hormone (LH) concentrations were much greater in the d16 group than those in the d30 and mature groups (p<0.01). Conversely, Fos-positive GnRH neurons were rarely observed in d16, and some Fos-positive GnRH neurons were observed in the d30 group (p<0.05 vs. saline) and the mature group (p<0.01 vs. saline). These results suggest that opiatergic inhibitory system on GnRH neuron in immature female rats is different from that in mature female rats.

Different expression of positive and negative regulators of hepatocyte growth in growing and shrinking hepatic lobes after portal vein branch ligation in rats

Portal vein branch embolization is often performed before hepatectomy to prevent postoperative liver failure. It is, however, still not clear how the embolized lobe shrinks and the non-embolized lobe proliferates in counterbalance. We investigated the expression of positive and negative regulators of hepatocyte growth to clarify the mechanisms of liver growth and atrophy in a rat portal vein ligation (PVL) model compared with partial hepatectomy (PH). A significant increase in DNA synthesis within the non-ligated lobe reached a peak at 36 h, a delay of 12 h as compared with PH, while no increase occurred in the ligated lobe. Expression of hepatocyte growth factor mRNA remarkably increased in the non-ligated growing lobe between 6 and 24 h, but was only slightly elevated in the ligated shrinking lobe. Contrarily, negative regulators of hepatocyte proliferation, such as TGF-beta1 and IL-1beta, were strongly expressed in the ligated shrinking lobe. Thus, the changes of portal venous flow and/or pressure caused by PVL may contribute to induction of different kinds of growth factors between the ischemic and non-ischemic lobes; these factors possibly regulate liver regeneration and atrophy after PVL.

Transplantation of highly differentiated immortalized human hepatocytes to treat acute liver failure

BACKGROUND

Temporary support of a damaged liver by a bioartificial liver (BAL) devise is a promising approach for the treatment of acute liver failure. Although human primary hepatocytes are an ideal source of hepatic function in BAL, shortage of human livers available for hepatocyte isolation is the limiting factor for the use of this modality. A clonal human hepatocyte cell line that can grow economically in culture and exhibit liver-specific functions should be an attractive solution to this problem.

METHODS

To test this alternative, primary human fetal hepatocytes were immortalized using Simian virus 40 large T antigen. To investigate the potential of the immortalized cells for BAL, we transplanted the cells into the spleen of adult rats and performed a 90% hepatectomy 12 hr later.

RESULTS

One of the cloned human liver cell lines, OUMS-29, showed highly differentiated liver functions. Intrasplenic transplanting of 20x10(6) OUMS-29 cells protected the animals from hyperammonemia and the associated hepatic encephalopathy. Survival was significantly prolonged in 90% of hepatectomized rats receiving OUMS-29 cells.

CONCLUSIONS

A highly differentiated immortalized human hepatocyte cell line, OUMS-29, was able to provide metabolic support during acute liver failure induced by 90% hepatectomy in rats. Essentially unlimited availability of OUMS-29 cells may be clinically useful for BAL treatment.

Preservation of fish cutlet (Pangasius pangasius) at ambient temperature by irradiation

Development of gamma irradiation preservation of ready-to-eat, commercially prepared fish cutlet and improvement of microbiological quality were studied. Studies on the shelf life extension by a combination of irradiation and ascorbic acid treatments of fish cutlets prepared at the laboratory and commercial scale have also been conducted. Cutlets prepared at the laboratory scale according to selected formulation and irradiated at a dose of 5 kGy could extend the shelf life up to 5 weeks at room temperature. In commercially prepared fish cutlets, maximum shelf life extension observed was 14 days for samples treated with 5 kGy of irradiation and stored at ambient temperature on the basis of combined microbiological, chemical, and organoleptic evaluation. The microbiological quality of the commercially prepared fish cutlets revealed the unhygienic conditions of the place where the fish was prepared and the unhygienic storage conditions and temperatures. As a result, the chemical and irradiation treatments were not effective in extending the shelf life of the cutlets under the storage condition used in this study compared with that of the laboratory scale-prepared cutlets.

Chemical constituents from the leaves of Hydrangea macrophylla var. thunbergii (III): Absolute stereostructures of hydramacrosides A and B, secoiridoid glucoside complexes with inhibitory activity on histamine release

Following the characterization of dihydroisocoumarin constituents, two secoiridoid glucoside complexes, called hydramacrosides A and B, were isolated from the leaves of Hydrangea macrophylla Seringe var. thunbergii Makino. The absolute stereostructures of hydramacrosides A and B were elucidated on the basis of chemical and physicochemical evidence, which included the application of the 13C-NMR glycosylation shift rule of 1,1'-disaccharides and the modified Mosher's method. Hydramacrosides A and B exhibited an inhibitory effect on histamine release from rat mast cells induced by an antigen-antibody reaction.

Experimental evaluation of the effects of the intraportal administration of cyclic guanosine monophosphate on ischemia/reperfusion in the porcine liver

This study was done to examine the protective effects of cyclic guanosine monophosphate (cGMP), a second messenger of nitric oxide, for ischemia/reperfusion injury of the liver, since it is known to induce vasodilatation and to inhibit platelet aggregation. Using an experimental model of porcine liver ischemia, 8-bromoguanosine 3',5' monophosphate, a cGMP analog, was continuously administered into the portal vein before ischemia and after reperfusion 30 min for each in the cGMP group (n = 6). Saline water was administered in the same way in the control group (n = 6). The cardiac output (CO), mean arterial blood pressure (MAP), portal venous flow (PVF), hepatic arterial flow (HAF), hepatic tissue blood flow (HTBF), and hepatic tissue cGMP level were determined. Hepatic enzymes and the bile discharge were also assessed as indicators of hepatic function. The hepatic tissue cGMP level was significantly higher, and PVF, HTBF, and the bile discharge were significantly greater in the cGMP group, while there were no remarkable differences between the groups with CO, MAP, HAF, and hepatic enzymes. In conclusion, the continuous supplementation of cGMP into the portal vein was found to be beneficial for preserving both the hepatic circulation and, consequently, the hepatic function after warm ischemia of porcine liver.

Flamingo controls the planar polarity of sensory bristles and asymmetric division of sensory organ precursors in Drosophila

The sensory bristles of the fruit fly Drosophila are organized in a polarized fashion such that bristles on the thorax point posteriorly. These bristles are derived from asymmetric division of sensory organ precursors (SOPs). The Numb protein, which is localized asymmetrically in a cortical crescent in each SOP, segregates into only one of the two daughter cells during cell division, thereby conferring distinct fates to the daughter cells [1] [2]. In neuroblasts, establishment of apical-basal polarity by the protein Inscuteable is crucial for orienting asymmetric division, but this is not the case for division of SOPs [3]. Instead, the Frizzled (Fz) protein mediates a planar polarity signal that controls the anteroposteriorly oriented first division (pl) of SOPs [4]. Here, we report that Flamingo (Fmi), a seven-transmembrane cadherin [5], controls the planar polarity of sensory bristles and the orientation of the SOP pl division. Both the loss of function and overexpression of fmi disrupted bristle polarity. During mitosis of the SOP, the axis of the pl division and the positioning of the Numb crescent were randomized in the absence of Fmi activity. Overexpression of Fmi and Fz caused similar effects. The dependence of proper Fmi localization on Fz activity suggests that Fmi functions downstream of Fz in controlling planar polarity. We also present evidence suggesting that Fz also functions in the Wingless pathway to pattern sensory organs.