Comparison of 35S- and digoxigenin-labeled RNA and oligonucleotide probes for in situ hybridization. Expression of mRNA of the seminal vesicle secretion protein II and androgen receptor genes in the rat prostate

Recent Advances in High-sensitivity In Situ Hybridization and Costs and Benefits to Consider When Employing These Methods

In situ hybridization (ISH), which visualizes nucleic acids in tissues and cells, is a powerful tool in histology and pathology. Over 50 years since its invention, multiple attempts have been made to increase the sensitivity and simplicity of these methods. Therefore, several highly sensitive in situ hybridization methods have been developed that offer researchers a wide range of options. When selecting these in situ hybridization variants, their signal-amplification principles and characteristics must be understood. In addition, from a practical point of view, a method with good monetary and time-cost performance must be chosen. This review introduces recent high-sensitivity in situ hybridization variants and presents their principles, characteristics, and costs.

Hybridization Chain Reaction Fluorescence In Situ Hybridization (HCR-FISH) in Ambystoma mexicanum Tissue

In situ hybridization is a standard procedure for visualizing mRNA transcripts in tissues. The recent adoption of fluorescent probes and new signal amplification methods have facilitated multiplexed RNA imaging in tissue sections and whole tissues. Here we present protocols for multiplexed hybridization chain reaction fluorescence in situ hybridization (HCR-FISH) staining, imaging, cell segmentation, and mRNA quantification in regenerating axolotl tissue sections. We also present a protocol for whole-mount staining and imaging of developing axolotl limbs.

Detection of MicroRNAs by In Situ Hybridization in Skin

MicroRNAs (miRNAs) are a family of small noncoding RNAs (~19-24 nt) playing a key role in the execution of gene expression programs in various cells and tissues. Many technical challenges have been encountered when investigating miRNAs, in particular, determining the spatiotemporal expression pattern of miRNAs in cells and tissues. We describe here a well-established in situ hybridization protocol for the detection and analysis of spatiotemporal expression patterns of miRNAs in skin and its appendages such as the hair follicle in both frozen and paraffin-embedded tissue sections. We describe in detail the different steps that are associated with utilizing in situ hybridization procedure on either frozen or paraffin-embedded tissues for miRNAs localization. Postfixation, tissues are hybridized with LNA double labeled probes with digoxygenin. Detection of hybridized probes is performed by using an alkaline phosphatase coupled antibody against digoxygenin. The final step involves the use of substrates to develop the color of alkaline phosphatase-LNA-probe structure leading to identification of the spatiotemporal location of target miRNAs in target tissue and cells. We also discuss two options for substrate color development in these procedures: (1) NBT/BCIP and (2) BM Purple. This method is a simple and convenient way of determining the spatiotemporal expression pattern of miRNAs, which has been a challenge since their discovery, due to their relatively small size. Knowledge gained from in situ hybridization is crucial for better understanding of the roles of individual miRNA(s) during distinct stages of development in various cells and tissues. These protocols will be beneficial to the wider scientific community.

Immunohistochemistry and RNA In Situ Hybridization in Mouse Brain Development

During development, the mouse brain is progressively divided into functionally distinct compartments. Numerous neuronal and glial cell types are subsequently generated in response to various inductive signals. Each cell expresses a unique combination of genes encoding proteins from transcription factors to neurotransmitters that define its role in brain function. To understand these important and highly sophisticated processes, it is critical to accurately locate the various proteins and cells that produce them. In this chapter, we introduce the techniques of Immunohistochemistry, which detects the localization of specific proteins, and RNA in situ hybridization, which enables the visualization of specific mRNAs.

OLFR734 Mediates Glucose Metabolism as a Receptor of Asprosin

Asprosin is a fasting-induced hormone that promotes glucose production in the liver and stimulates appetite in the hypothalamus by activating the cAMP signaling pathway via an unknown G protein-coupled receptor (GPCR). However, the bona fide receptor of Asprosin is unclear. Here, we have identified that the olfactory receptor OLFR734 acts as a receptor of Asprosin to modulate hepatic glucose production. Olfr734 knockout mice show a blunted response to Asprosin, including attenuated cAMP levels and hepatic glucose production, and improved insulin sensitivity. As Olfr734 deficiency dramatically attenuates both fasting and high-fat-diet-induced glucose production, our results demonstrate a critical role of OLFR734 as a receptor of Asprosin to maintain glucose homeostasis during fasting and in obesity.

Localization of Odorant Receptor Genes in Locust Antennae by RNA In Situ Hybridization

Insects have evolved sophisticated olfactory reception systems to sense exogenous chemical signals. These chemical signals are transduced by Olfactory Receptor Neurons (ORNs) housed in hair-like structures, called chemosensilla, of the antennae. On the ORNs' membranes, Odorant Receptors (ORs) are believed to be involved in odor coding. Thus, being able to identify genes localized to the ORNs is necessary to recognize OR genes, and provides a fundamental basis for further functional in situ studies. The RNA expression levels of specific ORs in insect antennae are very low, and preserving insect tissue for histology is challenging. Thus, it is difficult to localize an OR to a specific type of sensilla using RNA in situ hybridization. In this paper, a detailed and highly effective RNA in situ hybridization protocol particularly for lowly expressed OR genes of insects, is introduced. In addition, a specific OR gene was identified by conducting double-color fluorescent in situ hybridization experiments using a co-expressing receptor gene, Orco, as a marker.

A simple, sensitive and safe method to determine the human α/β-tryptase genotype

The human tryptase locus on chromosome 16 contains one gene encoding only β-tryptase and another encoding either β-tryptase or the homologous α-tryptase, providing α:β gene ratios of 0:4, 1:3 or 2:2 in the diploid genome, these genotypes being of potential clinical relevance in severe atopy. Using an EcoRV restriction site in α- but not β-tryptase, PCR products, spanning intron 1 to exon 5, were used to determine α/β-tryptase gene ratios using non-radioactive labels, including ethidium bromide labeling of all PCR products, and either digoxigenin-primer or DY682-primer labeling of only the final PCR cycle products. Sensitivity increased ∼60-fold with each final PCR cycle labeling technique. Ethidium bromide labeling underestimated amounts of α-tryptase, presumably because heteroduplexes of α/β-tryptase amplimers, formed during annealing, were EcoRV resistant. In contrast, both final PCR cycle labeling techniques precisely quantified these gene ratios, because only homoduplexes were labeled. Using the DY682-primer was most efficient, because PCR/EcoRV products could be analyzed directly in the gel; while digoxigenin-labeled products required transfer to a nitrocellulose membrane followed by immunoblotting. This technique for determining the α/β-tryptase genotype is sensitive, accurate, simple and safe, and should permit high-throughput screening to detect potential phenotype-genotype relations for α/β-tryptases, and for other closely related alleles.

Immunohistochemistry and RNA in situ hybridization in mouse brain development

During development, the mouse brain is progressively divided into functionally distinct compartments. Numerous neuronal and glial cell types are subsequently generated in response to various inductive signals. Each cell expresses a unique combination of genes encoding proteins from transcription factors to neurotransmitters that define its role in brain function. To understand these important and highly sophisticated processes, it is critical to accurately locate the various proteins and cells that produce them. In this chapter, we introduce the techniques of immunohistochemistry, which detects the localization of specific proteins, and RNA in situ hybridization, which enables the visualization of specific mRNAs.

Genomic characterization and transcriptional evidence for the involvement of complement component 7 in immune response of rock bream (Oplegnathus fasciatus)

The complement component 7 (C7) is the central mediator of pathogenic attack at the membrane surface and its binding to the C5b-7 complex triggers cytolytic signaling. In this study, C7 of rock bream (Oplegnathus fasciatus) was identified (Rb-C7) and characterized at the genomic level. The Rb-C7 gene contains 18 exons and 17 introns and is composed of a 2490 bp complete open reading frame (ORF). The encoded polypeptide (830 amino acids) contains a number of well-conserved C7 signature domains. Important putative transcription factor binding sites, including those for NF-κB, SP-1, C/EBP, AP-1 and OCT-1, are present in the 5'-flanking region of Rb-C7. Phylogenetic analysis revealed a close proximity of Rb-C7 with the orthologues in tilapia and Japanese flounder. Quantitative real-time PCR (qPCR) analysis confirmed constitutive Rb-C7 expression throughout all the examined tissue of healthy rock bream, with highest expression in liver. In immune challenge experiment, Rb-C7 expression was up-regulated in head kidney and liver in response to Edwardsiella tarda, Streptococcus iniae, lipopolysaccharide and rock bream iridovirus (RBIV). Furthermore, significant increases of both intracellular expression level and the number of Rb-C7-expressing cells were detected by in situ hybridization assay in head kidney and liver tissues upon E. tarda infection. These results suggested that Rb-C7 is lytic pathway gene in complement system and its transcriptional regulation may be an important immune response in pathogenic defense mechanism of rock bream.

Intra-tissue localization of an antibacterial L-amino acid oxidase in the rockfish Sebastes schlegeli

The rockfish Sebastes schlegeli skin mucus contains a potent antibacterial protein, SSAP (S. schlegeli antibacterial protein), a novel l-amino acid oxidase with strict substrate specificity that acts against water-borne Gram-negative bacteria. We previously demonstrated that SSAP distributes in the skin and gills. Here we investigated the intra-tissue localization of SSAP in the tissues by in situ hybridization. Skin and gill sections were hybridized with digoxigenin-conjugated SSAP-specific RNA probe. SSAP mRNA-positive cells located near the basal membrane of skin epidermis and the gill epithelium. Furthermore, skin section was analyzed by immunohistochemistry and reacted with anti-SSAP antiserum as a primary antibody. The mucus layer and mucous cells in the skin were immunopositive. Skin and gill extracts produced hydrogen peroxide, responsible for antibacterial activity, in the presence of l-lysine. These results suggested that SSAP functions locally as a humoral defense factor in S. schlegeli skin and gills and prevents pathogenic bacterial invasion.

Using in situ hybridisation to localize renal gene expression in tissue sections

The basics of in situ hybridization have been widely applied to a diverse range of situations where we need to localize the distribution of nucleic acids. Advances in other molecular techniques such as the advent of gene microarrays has not diminished the significance of in situ hybridization, but rather highlight the importance of being able to identify the topology of gene expression. In situ hybridization offers a degree of precision that is unavailable with other molecular techniques. This chapter outlines techniques used to examine the spatial distribution of gene expression in the kidney using complementary RNA (cRNA) probes with both radioactive and non-radioactive labels.

LINE-1 family member GCRG123 gene is up-regulated in human gastric signet-ring cell carcinoma

AIM: To analyze the expression profiles of a human gastric-cancer-related gene, GCRG123, in human gastric signet-ring cell carcinoma tissues, and to perform bioinformatics analysis on GCRG123.

METHODS: In situ hybridization was used to explore the GCRG123 expression pattern in paraffin-embedded gastric tissues, including 15 cases of signet-ring cell carcinoma, 15 of intestinal-type adenocarcinoma, and 15 of normal gastric mucosa. Northern blotting was used to analyze the differences in GCRG123 expression between stomach signet-ring cell carcinoma and intestinal-type adenocarcinoma tissues. Online software, including BLAST, Multalin and BLAT, were applied for bioinformatics analysis. National Center for Biotechnology Information (NCBI) and the University of California Santa Cruz (UCSC) databases were used for the analyses.

RESULTS: The in situ hybridization signal appeared as blue precipitates restricted to the cytoplasm. Ten out of 15 cases of gastric signet ring cell carcinoma, normal gastric mucosal epithelium and pyloric glands showed high GCRG123 expression. Low GCRG123 expression was observed in gastric intestinal-type adenocarcinoma and normal gastric glands. Northern blotting revealed that GCRG123 was up-regulated in signet-ring cell carcinoma tissue but down-regulated in intestinal-type adenocarcinoma tissue. BLAST and Multalin analyses revealed that the GCRG123 sequence had 92% similarity with the ORF2 sequence of human long interspersed nuclear element retrotransposons (LINE-1, L1). BLAT analysis indicated that GCRG123 mapped to all chromosomes. GCRG123 was found to integrate in the intron-17 and -23 of Rb, 5’ flanking region of IL-2 and clotting factor IX genes.

CONCLUSION: GCRG123, an active member of the L1 family, was up-regulated in human gastric signet-ring cell carcinoma.

EphB3 receptor and ligand expression in the adult rat brain

Eph receptors and ligands are two families of proteins that control axonal guidance during development. Their expression was originally thought to be developmentally regulated but recent work has shown that several EphA receptors are expressed postnatally. The EphB3 receptors are expressed during embryonic development in multiple regions of the central nervous system but their potential expression and functional role in the adult brain is unknown. We used in situ hybridization, immunohistochemistry, and receptor affinity probe in situ staining to investigate EphB3 receptors mRNA, protein, and ligand (ephrin-B) expression, respectively, in the adult rat brain. Our results indicate that EphB3 receptor mRNA and protein are constitutively expressed in discrete regions of the adult rat brain including the cerebellum, raphe pallidus, hippocampus, entorhinal cortex, and both motor and sensory cortices. The spatial profile of EphB3 receptors was co-localized to regions of the brain that had a high level of EphB3 receptor binding ligands. Its expression pattern suggests that EphB3 may play a role in the maintenance of mature neuronal connections or re-arrangement of synaptic connections during late stages of development.

A novel RNA-binding protein in neuronal RNA granules: regulatory machinery for local translation

Local translation in neuronal dendrites is an important basis for long-term synaptic plasticity, and RNA granules in the dendrites are involved in the local translation. Here, we identify RNG105 (RNA granule protein 105), a novel RNA-binding protein, as a component of the RNA granules in dendrites of hippocampal neurons. The RNG105-localizing RNA granules contain mRNAs, the translational products of which play key roles in synaptic plasticity. RNG105 has an ability to repress translation both in vitro and in vivo, consistent with the finding that the RNA granule is translationally arrested in the basal conditions. Dissociation of RNG105 from the RNA granules is induced by BDNF, a growth factor responsible for synaptic plasticity. The RNG105 dissociation is coincident with the induction of local translation near the granules. These findings suggest that RNG105 is a translational repressor in the RNA granules and provide insight into the link between RNG105 dynamics and local translational regulation.

Evidence for hepatocellular differentiation in alpha-fetoprotein-negative gastric adenocarcinoma with hepatoid morphology: a study with in situ hybridisation for albumin mRNA

AIM

Hepatoid adenocarcinoma, a putative chemosensitive tumour, is defined as a tumour with aberrant hepatocellular differentiation occurring in extrahepatic organs such as the stomach, usually in the gastrointestinal tract. Differentiation in the hepatocellular direction is usually supported by the production of alpha-fetoprotein (AFP) and, more recently, albumin (ALB) mRNA. We investigated ALB mRNA to address whether adenocarcinoma with hepatoid morphology, regardless of AFP production, can be diagnosed solely by morphological criteria as a hepatoid adenocarcinoma.

METHODS

We performed in situ hybridisation (ISH) and immunohistochemistry (IH) for ALB mRNA on AFP-negative gastric adenocarcinomas with hepatoid morphology. AFP-positive hepatoid adenocarcinomas and AFP-negative conventional gastric adenocarcinomas were also investigated as positive and negative controls, respectively.

RESULTS

All three gastric adenocarcinomas with hepatoid morphology with no evidence of AFP production stained positive for ALB mRNA, thus providing evidence of differentiation in the hepatocellular direction. Three of five cases of AFP-positive hepatoid adenocarcinoma of the stomach were positive for ALB mRNA, while 11 cases of AFP-negative conventional gastric adenocarcinoma were negative.

CONCLUSION

The present study demonstrates that, irrespective of AFP production, gastric adenocarcinoma with morphological patterns suggestive of hepatoid differentiation should be diagnosed as hepatoid adenocarcinoma with important prognostic implications.

Infectious salmon anemia virus RNA in fish cell cultures and in tissue sections of atlantic salmon experimentally infected with infectious salmon anemia virus

Current understanding of the etiopathogenesis of infectious salmon anemia (ISA) virus (ISAV) infection in fish comes mostly from virus detection in homogenized tissues taken from ISA-suspected mortalities. This study combined in situ hybridization (ISH) and histology to demonstrate viral RNA transcripts in different fish cell lines infected with ISAV and in tissues collected during the clinical phase of ISAV infection in Atlantic salmon. For this, a riboprobe to mRNA transcripts of ISAV RNA segment 8 was shown to detect viral mRNA in ISAV-infected TO, CHSE-214, and SHK-1 cell cultures. Specific hybridization was initially detected exclusively in the nuclei of infected cells, which is consistent with the nuclear transcription of orthomyxoviruses. For use of the riboprobe on fish tissues fixed in paraformaldehyde or formalin, the conditions used to permeabilize tissues before ISH (Proteinase K or Tween 20) were first optimized. Tissues were collected 15-20 days after challenge from 7 fresh mortalities of Atlantic salmon parr (approximately 20 g) showing severe gross and microscopic lesions, consistent with ISAV infection. Reverse transcription-polymerase chain reaction on tissue pools confirmed the presence of ISAV in each of the 7 fish. Of the tissues examined in each fish, the heart and liver consistently showed the strongest hybridization signal and, therefore, the most in situ virus, which was located in the endothelium of small blood vessels and in macrophage-like cells.

A novel diacylglycerol acyltransferase (DGAT2) is decreased in human psoriatic skin and increased in diabetic mice

Psoriasis is a skin disease with epidermal keratinocyte hyperproliferation and altered differentiation. To identify novel psoriasis-related genes, we investigated differentially expressed genes between normal and psoriatic skin. We identified a novel acyl CoA:diacylglycerol acyltransferase 2 (DGAT2) gene, which was decreased in human psoriatic skin. DGAT2 mRNA was expressed in sebaceous glands of normal human skin. DGAT2 protein was detected on endoplasmic reticulum. DGAT2 catalyzes the final step in the production of triglycerides and the accumulation of triglycerides in the tissues is considered to be related to insulin resistance. Therefore, we also investigated the expression of the DGAT2 gene in diabetic mice. DGAT2 mRNA was increased in the adipose, small intestine, and skeletal muscle in diabetic mice.

A gene encoding an apurinic/apyrimidinic endonuclease-like protein is up-regulated in human gastric cancer

AIM: To identify the gene that may predispose to human gastric cancer and to analyze its expression in gastric cancer and non-tumorous gastric mucosa.

METHODS: Cancer, para-tumor, and non-tumor gastric tissues were studied for gene expression profile using fluorescent differential display reverse transcription polymerase chain reaction (DDRT-PCR). The differentially expressed bands of interest were analyzed by cloning, Northern blotting, and sequencing. The sequencing results were compared with the GenBank database for homology and conserved domain analysis. In situ hybridization with DIG-labeled cRNA probes was used to detect the expression of gene in paraffin embedded gastric adenocarcinoma and non-cancerous tissues.

RESULTS: A gene expressed higher in tumor and para-tumor tissues than in their non-tumor counterparts of all 7 tested gastric adenocarcinoma patients was identified by means of DDRT-PCR analysis. It was named GCRG213 (gastric cancer related gene 213). Northern blot confirmed the differential expression. GCRG213 (GenBank No. AY053451) consisted of 1094 base pairs with an open reading frame (ORF) which encoded 142 amino acids. The deduced amino acid sequence contained a putative conserved domain, apurinic/apyrimidinic endonuclease (APE). In situ hybridization analysis showed that GCRG213 was expressed higher in gastric cancer tissues than in their corresponding non-tumor ones. Precancerous leisions of gastric adenocarcinoma showed a high GCRG213 expression, too. No difference of the expression patterns was found between the early and advanced gastric cancer.

CONCLUSION: A gene named GCRG213 was identified in human gastric adenocarcinoma. It encoded an APE-like protein which was probably a new member of the APE family. GCRG213 was over-expressed not only in gastric cancer, but also in its precancerous leisions. The role of GCRG213 expression in carcinogenesis needs further study.

Expression of the FAT10 gene is highly upregulated in hepatocellular carcinoma and other gastrointestinal and gynecological cancers

The ubiquitin-like modifier (UBL) family has recently generated much interest in the scientific community, as it is implicated to play important regulatory roles via novel protein-protein modification. FAT10 (diubiquitin) belongs to this family of proteins, comprising two ubiquitin-like moieties fused in tandem, and has been implicated to be involved in the maintenance of spindle integrity during mitosis. As FAT10 may play a role in the regulation of genomic stability, we examined if there is an association between FAT10 expression and hepatocellular carcinoma (HCC) or other cancers. Northern blot analyses revealed upregulation of FAT10 expression in the tumors of 90% of HCC patients. In situ hybridization as well as immunohistochemistry utilizing anti-FAT10 antibodies localized highest FAT10 expression in the nucleus of HCC hepatocytes rather than the surrounding immune and non-HCC cells. FAT10 expression was also found to be highly upregulated in other cancers of the gastrointestinal tract and female reproductive system. In conclusion, we demonstrated upregulation of FAT10 expression in various gastrointestinal and gynecological cancers. Its overexpression is unrelated to the general increase in protein synthesis or a general immune/inflammatory response to cancer. Rather, FAT10 may modulate tumorigenesis through its reported interaction with the MAD2 spindle-assembly checkpoint protein.

A novel gene, GCRG224, is differentially expressed in human gastric mucosa

AIM: To clone genes that may predispose us to human gastric cancer and to analyze it’s expression in gastric tissues.

METHODS: Specimens of paired tumor, paratumor and normal gastric mucosa tissues collected from fifteen patients who suffered from stomach antrum adenocarcinoma were used for analysis. Seven out of the fifteen cases were first studied by fluorescent differential display reverse transcription polymerase chain reaction (DDTR-PCR) analysis. The differentially expressed bands of interest were cloned, analyzed by Northern blot, sequencing and RT-PCR. Through BLAST, the sequencing results were compared with GenBank database for homology analysis. In situ hybridization with DIG-labeled cRNA probes was used to analyze the expression of interesting cDNA bands in paraffin embedded paired normal gastric mucosa and cancer tissues isolated from 30 gastric adenocarcinoma patients.

RESULTS: DDRT-PCR showed that one of the interesting cDNA bands, which was named W2, expressed much higher in all seven tested tumor and paratumor samples than in their normal counterparts, it was sub-cloned into a pGEM-T Easy vector. Two subclones were subsequently obtained. One of the subclone, GCRG224, was studied further. The sequencing result showed that GCRG224 consisted of 1159 base pairs and had one open reading frame (ORF). It located at human chromosome 11q14. No homologue was found in GenBank database with GCRG224-ORF. This nucleotide sequence data were submitted to GenBank with accession No. AF438406. RT-PCR showed that GCRG224 expressed higher in 11/15 gastric cancer tissues than in non-tumor tissues. However, the result of Northern blot analysis showed a higher GCRG224 expression in the non-tumor tissue than in the tumor one. Human multiple tissue Northern blot analysis revealed that GCRG224 also expressed in human normal colon tissue, and peripheral blood leukocyte. In situ hybridization analysis showed that only 5/30 adenocarcinoma, 3/18 dysplasia and 6/18 intestinal metaplasia showed higher GCRG224 expression level than the normal gastric glands. However, GCRG224 was over-expressed predominantly in 26/30 cases of normal mucosal epithelium.

CONCLUSION: A novel gene named GCRG224 was identified from human gastric mucosal tissue. It overexpressed in almost all gastric mucosal epithelium but only a small portion of cancer and precancerous leisions. The role of GCRG224 expression in gastric epithelium needs further study.

Interleukin-1beta expression in human gastric carcinoma with Epstein-Barr virus infection

The KT tumor is a transplantable strain of a human Epstein-Barr virus (EBV)-associated gastric carcinoma (EBVaGC), established in severe combined immunodeficiency (SCID) mice, with which the cytokine expression of EBVaGC can be investigated without interference from the infiltrating lymphocytes. As a part of a high-density oligonucleotide array (GeneChip) analysis of EBVaGC, the interleukin-1beta (IL-1beta) gene was the only cytokine gene that showed markedly higher expression in the KT tumor cells than in two tumor strains of EBV-negative GC. The results were confirmed by Northern blotting, Western blotting, and enzyme-linked immunosorbent assay. Furthermore, we demonstrated a positive signal for IL-1beta mRNA in the carcinoma cells of a surgically resected EBVaGC, but not in EBV-negative GC, by in situ hybridization. In vitro, IL-1beta increased the cell growth of a GC cell line, TMK1. Thus, IL-1beta may act as an autocrine growth factor in EBVaGC.

Ventral prostate predominant l, a novel mouse gene expressed exclusively in the prostate

BACKGROUND

Despite the region-specific nature of human prostate disease, there is a paucity of information regarding the molecular basis of prostate regionalization and patterning. To elucidate genetic mechanisms that underlie prostate growth and development, we investigated differential gene expression in mouse prostate lobes.

METHODS

mRNA differential display analysis was used to identify differentially expressed genes during development of ventral, anterior, and dorsolateral prostate lobes. Differential gene expression was confirmed by Northern blot analysis and RT-PCR.

RESULTS

A novel gene, Ventral prostate predominant1 (Vpp1) was identified. Vpp1 mRNA was evident in all lobes but accumulated predominantly in the ventral prostate, and was detected on postnatal day 7 through adulthood exclusively in the prostate gland. The steady-state level of Vpp1 mRNA decreased markedly in response to castration, suggesting androgen regulation of Vpp1 expression. Analysis of TRAMP tumors demonstrated a dramatic decrease in the level of Vpp1 mRNA.

CONCLUSIONS

The spatial distribution and early postnatal onset of Vpp1 expression is consistent with a role for this gene in prostate regionalization. The absolute prostate specificity of Vpp1 expression may allow this gene to serve as a paradigm to study the molecular basis of gene expression that is restricted exclusively to the prostate gland.

Application of molecular biology to impotence research

To encourage further application of molecular biology in impotence research, we have compiled a list of techniques that have been or can be used in such endeavors. While by no means complete or perfect, the list encompasses both some of the most commonly used (such as RT-PCR) and some of the most promising (such as gene chip) methods. All three levels of the gene expression hierarchy, namely, DNA, RNA, and protein, are represented in the discussion. Whenever possible, each technique is discussed with references relevant to impotence research. Interested readers therefore can trace the original or the most recent research protocols for more detailed information.

Cytokeratin expression patterns in jaw cyst linings with metaplastic epithelium

BACKGROUND

Cytokeratin (CK) expression patterns have been studied in numerous intact and diseased oral tissues. However, CK expression in metaplastic squamous cells has not been explored in depth and the origin of metaplastic epithelial linings of the jaw cysts has not been sufficiently investigated.

METHODS

We examined CK expression in 46 postoperative maxillary cysts (POMCs) which were lined with pseudostratified columnar cells only, columnar and squamous cells, and squamous cells only, in 13, 30 and 3 cases, respectively.

RESULTS

The expression of CK8, CK13 and CK18 were observed in 39, 9 and all 43 of the columnar epithelial linings, respectively. Metaplastic squamous epithelia expressed more CK13, and less CK18 and CK8. Of the 33 metaplastic linings, 24 expressed CK8, 23 CK13 and 26 linings expressed CK18. The patterns of expression of CK13 and CK18 observed were CK18(+)-CK13(-) in 10 metaplastic linings, CK18(+)-CK13(+) in 16, and CK18(-)-CK13(+) in 7. The expression of CK13- and CK18-mRNA was generally correlated with level of protein expressed. CK18-mRNA expression was observed by in situ hybridization, not only in the 26 metaplastic linings which were positive for CK18 protein, but also in five of the seven metaplastic linings which did not express CK18 protein. In addition, RT-PCR revealed an expression of CK18-mRNA in all metaplastic squamous linings, although the expression level was weaker than that in the columnar epithelial linings. The CK13-mRNA was expressed inversely to the CK18-mRNA.

CONCLUSIONS

These results indicate that CK18-mRNA is preserved through metaplasia, although the protein expression decreased. Metaplastic squamous cells differentiate with a decrease of CK18 and an increase of CK13 expression.

Expression of cytokeratins (CKs) 8, 13 and 18 and their mRNA in epithelial linings of radicular cysts: implication for the same CK profiles as nasal columnar epithelium in squamous epithelial lining

OBJECTIVE

Our objective was to specify cytokeratin (CK) patterns in lining epithelia of radicular cysts which are sometime lined with ciliated columnar epithelia as seen in the nasal epithelia.

MATERIALS AND METHODS

We examined the CK expression in 52 radicular cysts obtained from 32 maxillary and 20 mandibular lesions and investigated CK-mRNA expression using in situ hybridization in 24 maxillary and 13 mandibular cysts and reverse transcription-polymerase chain reaction (RT-PCR) in 24 maxillary cysts.

RESULTS

Of the maxillary cysts, 20, 29 and 19 squamous epithelial linings were positive for CK8, CK13 and CK18, respectively; of the mandibular cysts, 10, 20 and 11 linings were positive for these CKs, respectively. The expression patterns of CK18(+)-CK13(-), CK18(+)-CK13(+) and CK18(-)-CK13(+) were observed in 3, 16 and 13 linings of the maxillary cysts and 0, 11 and 9 linings of the mandibular cysts, respectively. In situ hybridization revealed the expression of CK18-mRNA in 9 and 4 linings of 24 maxillary and 13 mandibular cysts examined, respectively. With RT-PCR, we explored that both CK18- and CK13-mRNA were expressed not only in the normal nasal and gingival epithelia but also in the examined maxillary cyst linings although their expression levels differed correlating with the difference in CK staining.

CONCLUSION

It is concluded that CK13- and CK18-mRNA are constitutively expressed in columnar and squamous epithelial cells, respectively, and that the variant CK expression patterns with CK18-mRNA expression in maxillary radicular cysts are indicative of the possibility of phenotypic transformation in the cyst linings.

Identification of differentially expressed genes in rheumatoid arthritis by a combination of complementary DNA array and RNA arbitrarily primed-polymerase chain reaction

OBJECTIVE

There is increasing evidence that T cell-independent pathways, such as the up-regulation of protooncogenes and the production of growth factors and matrix-degrading enzymes, lead to progressive destruction of affected joints. Therefore, identification of differentially regulated genes restricted to rheumatoid arthritis (RA) synovial fibroblasts is essential. A combination of RNA arbitrarily primed-polymerase chain reaction (RAP-PCR) and complementary DNA (cDNA) array with defined genes was used for a highly sensitive differential screening using small amounts of RNA.

METHODS

RNA was extracted from cultured synovial fibroblasts obtained from 6 patients with RA and 6 patients with osteoarthritis (OA). RAP-PCR was performed using different arbitrary primers for first- and second-strand synthesis. PCRs were hybridized to cDNA array membranes. RA samples were compared with OA samples for differentially expressed genes.

RESULTS

In contrast to standard cDNA array, the identification of 12 differentially expressed genes in RA compared with OA (approximately 6%) was possible. Differentially expressed genes of interest were confirmed using semiquantitative RT-PCR and in situ hybridization.

CONCLUSION

Numerous variants of the differential display method and continuous improvements, including RAP-PCR, have proven to be both efficient and reliable for examining differentially regulated genes. Our results show that RAP-PCR combined with cDNA arrays is a suitable method for identifying differentially expressed genes in rheumatoid synovial fibroblasts, using very small amounts of RNA.

The Ca2+-binding proteins S100A8 and S100A9 are encoded by novel injury-regulated genes

To gain insight into the molecular mechanisms underlying cutaneous wound repair, we performed a large scale screen to identify novel injury-regulated genes. Here we show a strong up-regulation of the RNA and protein levels of the two Ca(2+)-binding proteins S100A8 and S100A9 in the hyperthickened epidermis of acute murine and human wounds and of human ulcers. Furthermore, both genes were expressed by inflammatory cells in the wound. The increased expression of S100A8 and S100A9 in wound keratinocytes is most likely related to the activated state of the keratinocytes and not secondary to the inflammation of the skin, since we also found up-regulation of S100A8 and S100A9 in the epidermis of activin-overexpressing mice, which develop a hyperproliferative and abnormally differentiated epidermis in the absence of inflammation. Furthermore, S100A8 and S100A9 expression was found to be associated with partially differentiated keratinocytes in vitro. Using confocal microscopy, both proteins were shown to be at least partially associated with the keratin cytoskeleton. In addition, cultured keratinocytes efficiently secreted the S100A8/A9 dimer. These results together with previously published data suggest that S100A8 and S100A9 are novel players in wound repair, where they might be involved in the reorganization of the keratin cytoskeleton in the wounded epidermis, in the chemoattraction of inflammatory cells, and/or in the defense against microorganisms.

Cloning and characterization of PIMT, a protein with a methyltransferase domain, which interacts with and enhances nuclear receptor coactivator PRIP function

The nuclear receptor coactivators participate in the transcriptional activation of specific genes by nuclear receptors. In this study, we report the isolation of a nuclear receptor coactivator-interacting protein from a human liver cDNA library by using the coactivator peroxisome proliferator-activated receptor-interacting protein (PRIP) (ASC2/AIB3/RAP250/NRC/TRBP) as bait in a yeast two-hybrid screen. Human PRIP-interacting protein cDNA has an ORF of 2,556 nucleotides, encodes a protein with 852 amino acids, and contains a 9-aa VVDAFCGVG methyltransferase motif I and an invariant GXXGXXI segment found in K-homology motifs of many RNA-binding proteins. The gene encoding this protein, designated PRIP-interacting protein with methyltransferase domain (PIMT), is localized on chromosome 8q11 and spans more than 40 kb. PIMT mRNA is ubiquitously expressed, with a high level of expression in heart, skeletal muscle, kidney, liver, and placenta. Using the immunofluorescence localization method, we found that PIMT and PRIP proteins appear colocalized in the nucleus. PIMT strongly interacts with PRIP under in vitro and in vivo conditions, and the PIMT-binding site on PRIP is in the region encompassing amino acids 773-927. PIMT binds S-adenosyl-l-methionine, the methyl donor for methyltransfer reaction, and it also binds RNA, suggesting that it is a putative RNA methyltransferase. PIMT enhances the transcriptional activity of peroxisome proliferator-activated receptor gamma and retinoid-X-receptor alpha, which is further stimulated by coexpression of PRIP, implying that PIMT is a component of nuclear receptor signal transduction apparatus acting through PRIP. Definitive identification of the specific substrate of PIMT and the role of this RNA-binding protein in transcriptional regulation remain to be determined.

Colocalization of porcine reproductive and respiratory syndrome virus and porcine circovirus 2 in porcine dermatitis and nephrology syndrome by double-labeling technique

Simultaneous detection of porcine reproductive and respiratory syndrome virus (PRRSV) and porcine circovirus 2 (PCV2) was achieved by a double-labeling technique using a combination of immunohistochemistry and in situ hybridization in five pigs with naturally occurring porcine dermatitis and nephropathy syndrome (PDNS). Both PRRSV and PCV2 were isolated from a homogenate of pooled skin and kidney from three pigs. PRRSV RNA was demonstrated by reverse transcription polymerase chain reaction (PCR) in skin, kidney, lymph node, and tonsil homogenates from all pigs. PCV2 DNA was demonstrated by PCR in kidney, lymph node, tonsil, liver, and lung homogenates from all pigs. For double-labeling studies, the tissue samples were processed sequentially, first by immunohistochemistry and then by in situ hybridization. The most consistent and intense staining for PRRSV and PCV2 was in the kidney, lymph node, and tonsil. PRRSV antigen and PCV2 DNA were also detected in the skin. This morphologic study is the first to confirm the presence of both PRRSV and PCV2 in the same tissues in pigs with naturally occurring PDNS.

Preparation of nonradioactive probes for in situ hybridization

In situ hybridization (ISH) enables the precise localization of RNA targets and provides an avenue to study the temporal and spatial patterns of expression of specific genes. ISH has evolved from being an esoteric technique to one that is routinely used by researchers in many areas of research. A major driving force has been the development of numerous nonisotopic labeling and signal detection methods. Historically, radioactive probes and autoradiography provided sensitivity that was unattainable with nonisotopic probes. But the long exposure times required for signal detection and the perceived dangers associated with radioactivity limit its use. Advances in nonisotopic detection systems have overcome many of the limitations associated with using radiolabeled probes. One of the most significant contributions from nonisotopic methods is the ability to discriminate between multiple nucleic acid sequences simultaneously.

Isolation and characterization of a novel liver-specific gene, hepassocin, upregulated during liver regeneration

By differential cDNA cloning coupled with Xenopus oocyte expression screening, we isolated a cDNA encoding a novel protein, termed 'hepassocin', the expression of which is upregulated in the regenerating rat liver. The cDNA contained a single open reading frame encoding a protein of 314 amino acids (ca. 34 kDa), including 24 amino acids of signal sequence. The protein expressed from the cDNA in Verots cells had activity to stimulate DNA synthesis in primary rat hepatocytes and was of 66 kDa or 34 kDa, under non-reducing or reducing conditions, respectively. Using an affinity column conjugated with the antibody raised against a peptide in a hydrophilic region, we purified hepassocin from the rat liver: it had a DNA synthesis-stimulating activity in hepatocytes. The hepassocin obtained here was 66 kDa, and the 34 kDa protein obtained under reducing conditions contained five cysteine residues, indicating that hepassocin is active as a homodimer. Northern blot analysis revealed that hepassocin mRNA (1.4 kb in length) occurred only in the liver, and in situ hybridization studies revealed its presence in parenchymal hepatocytes but not in endothelial cells. Furthermore, the expression of hepassocin mRNA was upregulated during compensatory hyperplasia after partial hepatectomy and regeneration after galactosamine treatment in the rat liver. These results suggest that hepassocin plays an important role in stimulating liver cell growth, through an autocrine mechanism.

Expression of alpha-calcitonin gene-related peptide in the enteric nervous system of rat small intestine

We first detected alpha-calcitonin gene-related peptide (alpha-CGRP) precursor mRNA in the enteric nervous system (ENS) of rat small intestine by reverse transcriptase polymerase chain reaction (RT-PCR). The nucleotide sequence of the RT-PCR product was completely identical to that found in other organs. By in situ hybridization using digoxygenin-labeled alpha-CGRP precursor cRNA probe, we found that antisense probes detected a signal on nerve cell bodies of both submucosal and myenteric plexuses. Our findings indicate that the rat ENS participates in synthesis of alpha-CGRP precursor.

The DAZL1 gene is expressed in human male and female embryonic gonads before meiosis

The human DAZL1 gene (known also as DAZH or DAZLA) is the autosomal homologue of the Y-chromosomal DAZ gene which has been found to be deleted in azoospermic males. Evidence suggests that the role of DAZL1 may not be restricted to spermatogenesis, but may include oogenesis as well. In order to study the function of human DAZL1 gene in the ovary, we observed its expression pattern during embryonic development. RNA in-situ hybridization showed that DAZL1 transcripts were localized to a subset of cells (somatic versus germ cells) in human embryonic ovary (23 weeks of gestation) and testis (21 weeks gestation). In the ovary, DAZL1 transcripts were found in oogonia and in oocytes and granulosa cells of primordial follicles. In the testis, DAZL1 transcripts were identified exclusively in the germ cells. Our results demonstrate high similarity between the human DAZL1 and the mouse Dazl1 gene expression patterns during embryonic development, suggesting that the human gene functions at the first phase of gametogenesis, just as in the mouse, where Dazl1 mutations cause male and female sterility.

Impaired endochondral ossification and angiogenesis in mice deficient in membrane-type matrix metalloproteinase I

Membrane-type matrix metalloproteinase I (MT1-MMP)-deficient mice were found to have severe defects in skeletal development and angiogenesis. The craniofacial, axial, and appendicular skeletons were severely affected, leading to a short and domed skull, marked deceleration of postnatal growth, and death by 3 wk of age. Shortening of bones is a consequence of decreased chondrocyte proliferation in the proliferative zone of the growth plates. Defective vascular invasion of cartilage leads to enlargement of hypertrophic zones of growth plates and delayed formation of secondary ossification centers in long bones. In an in vivo corneal angiogenesis assay, null mice did not have angiogenic response to implanted FGF-2, suggesting that the defect in angiogenesis is not restricted to cartilage alone. In tissues from null mice, activation of latent matrix metalloproteinase 2 was deficient, suggesting that MT1-MMP is essential for its activation in vivo.

Activation of the IL-4 STAT pathway in rheumatoid synovium

STATs act as second messenger after binding of a signaling molecule to its receptor. IL-4 STAT is directly involved in the IL-4-dependent gene transcription in the nucleus. We examined the expression and activation of IL-4 STAT and its related kinase Jak-1 in rheumatoid synovium. Rheumatoid arthritis (RA) synovial frozen sections of patients with short-term (<1 year) and long-term disease (>2 years) were examined using in situ hybridization and immunohistochemistry. IL-4 STAT mRNA could be detected in synovium of patients with short-term and long-term RA. The most intensive expression of IL-4 STAT mRNA could be seen in follicular inflammatory infiltrates. In the synovial lining, both fibroblasts and macrophages expressed IL-4 STAT mRNA. IL-4 STAT and Jak-1 protein was expressed by synoviocytes, and up-regulation could be induced after stimulation with IL-4. Activation of IL-4 STAT was reflected by phosphorylation of IL-4 STAT. The results indicate that IL-4 STAT is involved in key pathomechanisms in RA synovium and that IL-4 STAT-dependent pathways operate in early and late stages of the disease and presumably contribute to inhibitory immune mechanisms in RA synovium.

PSP94 (or beta-microseminoprotein) is a secretory protein specifically expressed and synthesized in the lateral lobe of the rat prostate

BACKGROUND

Prostatic secretory protein of 94 amino acids (PSP94), also called beta-microseminoprotein, is a small, nonglycosylated protein, rich in cysteine residues. It was first isolated as a major protein from human seminal plasma. Subsequently, its homologous proteins were identified, and their cDNAs or genes have been cloned in primates, pigs, and rodents.

METHODS

The present study investigated the expression pattern of PSP94 in the normal Noble rat prostate gland by nonradioactive in situ hybridization, Northern blotting, RT-PCR, Western blotting, and immunohistochemistry. Its expression in the mouse prostate gland was also examined by in situ hybridization.

RESULTS

The results of in situ hybridization, and Northern and Western blot analyses, showed that the expression of rat PSP94 was prostate-specific. It was highly expressed in the lateral prostatic lobe, moderate in the dorsal lobe, weak in the coagulating gland, and negative in the ventral lobe and seminal vesicle. Its specific expression in the rat prostate gland was further confirmed by RT-PCR analysis of prostatic and nonprostatic organ tissues. Its mRNA transcripts were not detected in the urinary, digestive, and respiratory tracts, male and female reproductive organs, muscles, brain, and kidney. Its molecular mass was estimated to be 14.5 kDa by Western blotting. Similar prostate-specific expression of PSP94 was also observed by in situ hybridization in the lateral lobe, but not in the dorsal and ventral lobe, of the mouse prostate gland.

CONCLUSIONS

Rat PSP94 is a major secretory protein highly expressed and synthesized by the lateral lobe of both rat and mouse prostate glands, and moderately expressed in the dorsal lobe of the rat prostate gland.

Type 1 vasoactive intestinal peptide receptor expression in PC3/AR cells is evidence of prostate epithelial differentiation

BACKGROUND

Type 1 vasoactive intestinal peptide receptor (VIP1R) is expressed in many secretory epithelial cells. We investigated VIP1R expression as a marker of prostate secretory epithelial differentiation in normal and malignant prostate tissues and in PC-3 human prostate cancer cells either lacking or expressing a functional androgen receptor.

METHODS

VIP1R mRNA in rat prostate was assessed by in situ hybridization. VIP1R mRNA in human prostate tissue was identified by Northern blot hybridization. VIP1R mRNA expression in human prostate cancer cell lines in the presence or absence of androgen was determined by semiquantitative reverse transcription-polymerase chain reaction (RT-PCR). Human prostate cell lines were treated with VIP, and changes in intracellular cAMP were measured by radioimmunoassay.

RESULTS

VIP1R mRNA was expressed only in epithelial cells in normal rat prostate. VIP1R mRNA was present in both normal and malignant human prostate. Well-differentiated LNCaP cells expressed functional VIP receptors, while poorly differentiated PC-3 cells did not. PC-3 cells stably expressing the androgen receptor (PC3/AR) did express functional VIP receptors, but VIP1R mRNA levels were not androgen-regulated.

CONCLUSIONS

VIP1R expression indicates epithelial differentiation in normal and malignant prostate. PC3/AR cells and LNCaP cells, both of which express VIP1R and prostate-specific antigen (PSA), are the only prostate cancer cell lines known to express these two markers of prostate epithelial differentiation.

Decay-accelerating factor in guinea pig stomachs following ischemia reperfusion stress

A complement regulatory protein, decay-accelerating factor (DAF, CD55), is known to protect host tissues from autologous complement activation. DAF is present on the apical side of human gastric epithelial cells, and its expression increases during gastritis. To develop an animal model for analysis of DAF expression on gastric cells, a mAb to guinea pig DAF was successfully used. Although DAF expression in the mucosal epithelium of the stomach is weak, as judged by immunohistochemical staining with the mAb, it was temporarily up-regulated at 12 and 24 h, and at 3 days after ischemia reperfusion (I/R) (p < 0.05). The DAF mRNA level in gastric tissues was determined by Northern blot analysis and found to be highest at 6 h after I/R, returning to the baseline at 24 h. Strong DAF mRNA expression was observed in the cytoplasm of cells beneath the eroded tissues 6 h after I/R. In guinea pigs, alternative splicing of DAF mRNA generates both GPI-anchored types and transmembrane types of DAF. RT-PCR analysis revealed that mRNAs of the transmembrane types had become significantly dominant by 6 h after I/R, whereas levels for the GPI-anchored types remained unchanged. In guinea pigs depleted of complement by cobra venom factor treatment, the area of erosion and the up-regulation of DAF expression in gastric epithelial cells after I/R were significantly limited compared with the normocomplementemic group, indicating that DAF may be up-regulated by an inflammatory stress.

Localization of 5-oxo-L-prolinase mRNA in the murine choroid plexus by in situ hybridization

The gamma-glutamyl cycle is thought to play a significant role in the transport of amino acids between the blood and the cerebrospinal fluid. In the present study we investigated the expression of 5-oxo-L-prolinase, an enzyme of this pathway, in mouse brain and kidney by in situ hybridization using digoxygenin-labeled RNA probes. Expression of 5-OPase mRNA was found in epithelial cells of the proximal tubules in kidney as well as in the epithelium and vascular endothelial cells of the choroid plexus but not in periventricular capillaries.

In situ hybridization study of PSP94 (prostatic secretory protein of 94 amino acids) expression in human prostates

BACKGROUND

The prostatic secretory protein of 94 amino acids (PSP94), also named beta-microseminoprotein, is one of the major proteins secreted by the human prostate. However, its value as a prognostic marker for prostate cancers is still under debate. The aim of the present study was to examine the expression pattern of this protein in fetal, pubertal, and aged human prostates.

METHODS

Nonisotopic in situ hybridization using a digoxigenin-labeled riboprobe for PSP94 and immunohistochemistry were used to demonstrate the expression of PSP94 in different regions or zones of fetal, pubertal, and adult human prostates. Its localization pattern was also compared with those of two other major secretory proteins, prostate-specific antigen (PSA) and prostatic acid phosphatase (PAP), by immunohistochemistry.

RESULTS

PSP94 mRNA and its protein were localized to the secretory epithelium of normal pubertal and adult human prostates. No hybridization signal and immunoreactivity of PSP94 were seen in fetal prostates at 6-7 months of gestation, whereas some glandular cells were positive to PSA and PAP immunostainings. In the adult prostates, PSP94 expression was intense in the acini in the peripheral zone, less intense in the transition zone, and variable in the central zone. Such a zonal expression pattern was more apparent in the pubertal prostates. However, no obvious differential expression pattern was observed in the immunohistochemistry of PAP and PSA, which showed a uniform staining of the secretory epithelia of the acini in all anatomic zones. The hybridization signals and immunoreactivity of PSP94 became reduced or lost in premalignant prostatic intraepithelial neoplastic lesions and different grades of prostatic carcinomas.

CONCLUSIONS

Fetal prostates at 6-7 months of gestation already synthesize PSA and PAP but not PSP94. The delayed expression of PSP94 appears to correlate with the development of the prostate gland. A differential expression pattern of PSP94 is demonstrated in different anatomical zones, showing that this protein is more expressed and synthesized in the acini in the peripheral zone than in the central and transition zones. However, such a zonal pattern is not seen in the immunohistochemistry of PSA and PAP. The present study also shows that PSP94 is downregulated in different grades of prostate cancers.

Telomerase activity and in situ telomerase RNA expression in oral carcinogenesis

To investigate the role of telomerase in oral carcinogenesis, we assayed telomerase activity in various oral tissues by a modified telomeric repeat amplification protocol (TRAP) analysis. Also, using digoxigenin-labeled probes, we measured the in situ expression of human telomerase RNA component (hTR) in paired oral squamous cell carcinomas (OSCC) and adjacent non-cancerous matched tissue (NCMT). We detected telomerase activity in three OSCC cell lines, but not in primary oral keratinocytes. In patient samples, most OSCC (36/42, 86%) and oral premalignant lesions (8/12, 67%) possessed telomerase activity. In addition, 6 of 27 (22%) NCMT contained weak telomerase activity. In situ hybridization showed that hTR was expressed in almost all OSCC (23/27, 85%) as well as in the majority of NCMT (20/25, 80%). In most cases, accumulation of hTR was observed both in the nucleus and cytoplasm of epithelial cells. A correlation between hTR expression and more advanced tumor grade was observed. The appearance of telomerase activation and hTR expression during oral carcinogenesis was different. This study indicates that the activation of telomerase is an early and frequent event in OSCC.

Cushing's syndrome secondary to ectopic ACTH secretion from metastatic breast carcinoma

Breast carcinoma is a rare cause of ectopic ACTH syndrome. There are only two previously reported cases in which ACTH secretion is documented. We describe the case of a 56-year-old woman who presented with clinical and biochemical features of ectopic ACTH syndrome in the setting of metastatic breast carcinoma. Despite aggressive management of her ectopic ACTH syndrome, her course was complicated by opportunistic infection, respiratory failure and death. Immunostaining of the breast metastases for ACTH was positive and in situ hybridization revealed proopiomelanocortin gene expression. This is the first reported case of ectopic ACTH syndrome associated with metastatic breast cancer in which the technique of in situ hybridization has been used to confirm the breast cancer metastases as the source of ectopic ACTH secretion.

Gene transfer of cytokine inhibitors into human synovial fibroblasts in the SCID mouse model

OBJECTIVE

To investigate the effects of retrovirus-based gene delivery of inhibitory cytokines and cytokine inhibitors into human synovial fibroblasts in the SCID mouse model of rheumatoid arthritis (RA).

METHODS

The MFG vector was used for gene delivery of tumor necrosis factor alpha receptor (TNFalphaR) p55, viral interleukin-10 (IL-10), and murine IL-10 into RA synovial fibroblasts. The effect on invasion of these cells into human articular cartilage and on perichondrocytic cartilage degradation was examined after 60 days of coimplantation into the SCID mouse.

RESULTS

TNFalphaR p55 gene transfer showed only a limited effect on inhibition of RA synovial fibroblast invasiveness and cartilage degradation. In contrast, invasion of the RA synovial fibroblasts into the coimplanted cartilage was strongly inhibited by both viral and murine IL-10. Perichondrocytic cartilage degradation was not affected by either form of IL-10.

CONCLUSION

The data show that cytokines can be successfully inserted into the genome of human RA synovial fibroblasts using a retroviral vector delivery system, and that the SCID mouse model of human RA is a valuable tool for examining the effects of gene transfer. In addition, inhibition of more than one cytokine pathway may be required to inhibit both synovial- and chondrocyte-mediated cartilage destruction in RA.

cDNA, genomic cloning, and gene expression analysis of mouse PSP94 (prostate secretory protein of 94 amino acids)

The potential use of prostate secretory protein of 94 amino acids (PSP94) as a diagnostic biomarker or a therapeutic agent for prostate cancer has been reported. In order to establish an animal model to further elucidate on its biological role, we cloned the mouse PSP94 cDNA (approximately 500 bp) by reverse transcriptase-polymerase chain reaction (RT-PCR) and disclosed its genomic structure. The whole mouse PSP94 gene (approximately 23 kb) was amplified by long and accurate-PCR and also cloned by screening of a mouse embryo stem-cell genomic library. Computational and statistical analyses have demonstrated several highly conserved characteristics of PSP94 among different species. Comparison of PSP94 from human, two primates, pig, and rodents revealed that the most significant feature is that PSP94 is rich in cysteines (10% of the total sequence) and their positions are highly conserved. The three intron-four exon structure of the human PSP94 gene and the consensus sequence (....GT-intron-AG...) for mRNA splicing are also strongly conserved. A high divergence in cDNA sequence in the protein-coding region and also in the genomic sequence of PSP94 was also observed among these species. Comparing with alpha-globin, a typical evolutionally conserved gene, with the PSP94 gene, the rate of nonsynonymous changes per site per year (kN) is 2 to 6 times higher, indicating that PSP94 gene has been under far fewer evolutionary constraints than other genes and has a potential role as a species barrier in reproductive biology. In order to test this hypothesis, we investigated the gene expression of PSP94 and its tissue distribution in various rodent tissues by RT-PCR and in situ hybridization (ISH). Gene expression was found only in the prostate, suggesting that PSP94 is probably more tissue specific in the prostate of rodents than in mammals. The ISH analysis also revealed a prostate lobe-specific expression of the PSP94 gene in both mice and rats. It was strongly expressed in the lateral prostate, but the findings were negative in the dorsal and ventral lobe. Therefore, it is hypothesized that one of the primary functions of rodent PSP94, as a major prostate secretory protein, is related to reproductive biology.

Kinesin-like protein CENP-E is upregulated in rheumatoid synovial fibroblasts

Articular destruction by invading synovial fibroblasts is a typical feature in rheumatoid arthritis (RA),. Recent data support the hypothesis that key players in this scenario are transformed-appearing synovial fibroblasts at the site of invasion into articular cartilage and bone. They maintain their aggressive phenotype toward cartilage, even when first cultured and thereafter coimplanted together with normal human cartilage into severe combined immunodeficient mice for and extended period of time. However, little is known about the upregulation of genes that leads to this aggressive fibroblast phenotype. To inhibit this progressive growth without interfering with pathways of physiological matrix remodelling, identification of pathways that operate specifically in RA synovial fibroblasts is required. In order to achieve this goal, identification of genes showing upregulation restricted to RA synovial fibroblasts is essential.

AIMS

To identify specifically expressed genes using RNA arbitrarily primed (RAP)-polymerase chain reaction (PCR) for differential display in patients with RA.

METHODS

RNA was extracted from cultured synovial fibroblasts from 10 patients with RA, four patients with osteoarthritis (OA), and one patient with psoriatic arthritis. RAP-PCR was performed using different arbitrary primers for first-strand and second-strand synthesis. First-strand and second-strand synthesis were performed using arbitrary primers: US6 (5'-GTGGTGACAG-3') for first strand, and Nuclear 1+ (5'ACGAAGAAGAG-3'), OPN28 (5'GCACCAGGGGG-3'), Kinase A2+(5'-GGTGCCTTTGG-3') and OPN24 (5'AGGGGCACCA-3') for second strand synthesis. PCR reactions were loaded onto 8 mol/l urea/6% polyacrylamide-sequencing gels and electrophoressed. Gel slices carrying the target fragment were then excised with a razor blade, eluated and reamplified. After verifying their correct size and purity on 4% agarose gels, the reamplified products derived from the single-strand confirmation polymorphism gel were cloned, and five clones per transcript were sequenced. Thereafter, a genbank analysis was performed. Quantitative reverse transcription PCRj of the segments was performed using the PCR MIMIC technique. In-situ expression of centromere kinesin-like protein-E (CENP-E) messenger (m)RNA in RA synovium was assessed using digoxigenin-labelled riboprobes, and CENP-E protein expression in fibroblasts and synovium was performed by immunogold-silver immunohistochemistry and cytochemistry. Functional analysis of CENP-E was done using different approaches (eg glucocorticoid stimulation, serum starvation and growth rate analysis of synovial fibroblasts that expressed CENP-E).

RESULTS

In RA, amplification of a distinct PCR product suitable for sequencing could be observed. The indicated complementary DNA fragment of 434 base pairs from RA mRNA corresponded to nucleotides 6615-7048 in the human centromere kinesin-like protein CENP-E mRNA (GenBank accession No. emb/Z15005). The isolated sequence shared greater than 99% nucleic acid (P=2.9e(-169)) identify with the human centromere kinesin-like protein CENP-E. Two base changes at positions 6624 (A to C) and 6739 (A to G) did not result in alteration in the amino acid sequence, and therefore 100% amino acid identity could be confirmed. The amplification of 10 clones of the cloned RAP product revealed the presence of CENP-E mRNA in every fibroblast culture examined, showing from 50% (271.000 +/- 54.000 phosphor imager arbitrary units) up to fivefold (961.000 +/- 145.000 phosphor image arbitrary units) upregulation when compared with OA fibroblasts. Neither therapy with disease-modifying antirheumatic drugs such as methotrexate, gold, resochine or cyclosporine A, nor therapy with oral steroids influenced CENP-E expression in the RA fibroblasts. Of the eight RA fibroblast populations from RA patients who were receiving disease-modifying antirheumatic drugs, five showed CENP-E upregulation; and of the eight fibroblast populations from RA patients receiving steroids, four showed CENP-E upregulation. Numerous synovial cells of the patients with RA showed a positive in situ signal for the isolated CENP-E gene segment confirming CENP-E mRNA production in rheumatoid synovium, whereas in OA synovial tissue CENP-E mRNA could not be detected. In addition, CENP-E expression was independent from medication. This was further confirmed by analysis of the effect of prednisolone on CENP-E expression, which revealed no alteration in CENP-E mRNA after exposure to different (physiological) concentrations of prednisolone. Serum starvation also could not suppress CENP-E mRNA completely.

DISCUSSION

Since its introduction in 1992, numerous variants of the differential display method and continuous improvements including RAP-PCR have proved to have both efficiency and reliability in examination of differentially regulated genes. The results of the present study reveal that RAP-PCR is a suitable method to identify differentially expressed genes in rheumatoid synovial fibroblasts. The mRNA, which has been found to be upregulated in rheumatoid synovial fibroblasts, codes for a kinesin-like motor protein named CENP-E, which was first characterized in 1991. It is a member of a family of centromere-associated proteins, of which six (CENP-A to CENP-F) are currently known. CENP-E itself is a kinetochore motor, which accumulates transiently at kinetochores in the G2 phase of the cell cycle before mitosis takes place, appears to modulate chromosome movement and spindle elongation,and is degraded at the end of mitosis. The presence or upregulation of CENP-E has never been associated with RA.The three-dimensional structure of CENP-E includes a coiled-coil domain. This has important functions and shows links to known pathways in RA pathophysiology. Coiled-coil domains can also be found in jun and fos oncogene products, which are frequently upregulated in RA synovial fibroblasts. They are also involved in DNA binding and transactivation processes resembling the situation in AP-1 (Jun/Fos)-dependent DNA-binding in rheumatoid synovium. Most interestingly, these coiled-coil motifs are crucial for the assembly of viral proteins, and the upregulation of CENP-E might reflect the influence of infectious agents in RA synovium. We also performed experiments showing that serum starvation decreased, but did not completely inhibit CENP-E mRNA expression. This shows that CENP-E is related to, but does not completely depend on proliferation of these cells. In addition, we determined the growth rate of CENP-E high and low expressors, showing that it was independent from the amount of CENP-E expression. supporting the statement that upregulation of CENP-E reflects an activated RA fibroblast phenotype. In summary, the results of the present study support the hypothesis that CENP-E, presumably independently from medication, may not only be upregulated, but may also be involved in RA pathophysiology.