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Results for “differential peptide expression”

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PubMed2004

Vasoactive intestinal peptide increases vascular endothelial growth factor expression and neuroendocrine differentiation in human prostate cancer LNCaP cells.

Vasoactive intestinal peptide (VIP) upregulates the expression of vascular endothelial cell growth factor (VEGF(189), VEGF(165) and VEGF(121)) mRNAs in human prostate cancer LNCaP cells, as shown by reverse transcriptase-polymerase chain reaction (RT-PCR). Real-time RT-PCR indicated that the effect was maximal by 1-2 h and must be accounted for increased transcription since VIP decreased VEGF(165) mRNA stability. VIP stimulated VEGF(165) protein synthesis as measured by ELISA. VIP regulation of VEGF expression was mediated by VPAC(1) receptor and was cAMP/protein kinase A (PKA) dependent. Phosphoinositide 3-kinase (PI3-K) and mitogen-activated protein kinase MEK1/2 systems may also be involved as shown with specific kinase inhibitors. These actions together with the observation of VIP-induced neuroendocrine differentiation in LNCaP cells suggest a proangiogenic potential of VIP in prostate cancer.

Cell Line, Tumor↗

PubMed2006

Gangliocytes in neuroblastic tumors express alarin, a novel peptide derived by differential splicing of the galanin-like peptide gene.

In neuroblastic tumors a relationship of differentiation of the tumor to galanin receptor expression and antiproliferative and apoptotic effects upon activation of galanin receptors in neuroblastoma cells was reported. To elucidate the expression of other components of the galanin peptide family in neuroblastic tumors, RT-PCR analysis of a variety of human neuroblastic tumor tissues was performed. Ganglioneuroma tissues revealed the presence of a splice variant of the galanin-like peptide (GALP) mRNA, which results in exclusion of exon 3 and a frame shift after the signal peptide sequence of GALP. This generates a peptide of 25 amino acids, which we have termed alarin because of the N-terminal alanine and the C-terminal serine. The novel neuropeptide alarin does not reveal significant homology to other peptides. Immunohistochemistry with antibodies directed against synthetic alarin peptide detected specific cytoplasmic granular staining in ganglia of human ganglioneuroma and ganglioneuroblastoma, as well as differentiated tumor cells of neuroblastoma tissues. Undifferentiated neuroblasts of these tumor tissues did not show alarin-like immunoreactivity and alarin-specific mRNA. Our findings indicate that alarin expression is a feature of ganglionic differentiation in neuroblastic tumor tissues.

Amino Acid Sequence↗

PubMed1997

Immunoselection in vivo: independent loss of MHC class I and melanocyte differentiation antigen expression in metastatic melanoma.

Peptides derived from melanocyte differentiation antigens have been identified as targets for MHC class I-restricted cytolytic T lymphocytes (CTLs) in human melanoma Regression of antigen-expressing tumors as well as selection of antigen-loss variants in the presence of antigen-specific CTLs have previously been reported. In the present study, we determined the expression of the melanocyte differentiation antigens Melan A/MART-1 and tyrosinase by mRNA analysis and by immunohistochemical staining with the monoclonal antibodies (MAbs) A103 and T311. Co-expression of Melan A/MART-1 and tyrosinase was detected by both methods in 18/20 melanomas tested. However, immunohistochemistry provided additional information on intensity and microheterogeneity of antigen expression that cannot be detected by mRNA analysis as a molecular basis for the escape from CTL recognition of antigen-negative tumor cells. Comparative analysis of repeated biopsies of metastatic lesions in 5 HLA-A2+ patients showed a gradual loss of Melan A/MART-1 expression in 4/5 and of tyrosinase in 2/5 samples in association with tumor progression. However, 3 of these patients had growing antigen-positive tumors in the presence of antigen-specific CTLs. This led us to assess the expression of MHC class I, the essential restriction element for CTL recognition, and of HLA-A2. We found an unexpectedly high frequency of MHC class I-negative tumors (9/20). Loss of MHC class I expression was detected in 3/5 progressive tumors and isolated loss of HLA-A2 in 1/5 tumors. Our results suggest that strategies enhancing the expression of MHC class I and tumor-associated antigens need to be considered in attempts at making vaccination more effective.

Adult↗

PubMed2004

Expression of natriuretic peptides in rat Müller cells.

Natriuretic peptides (NPs) have been shown to modulate neuronal activities. By immunohistochemistry and confocal microscopy, we examined expression of atrial NP (ANP), brain NP (BNP) and C-type NP (CNP) in rat retina. Our results showed that these peptides were differentially expressed in the neural retina. While strong ANP-, BNP- and CNP-immunoreactivity (IR) was clearly seen in the outer and inner plexiform layers and on numerous neurons in the inner nuclear layer, BNP- and CNP-, but not ANP-IR, was present in some ganglion cells. Furthermore, ANP, BNP and CNP were expressed in Müller cells with distinct profiles, as shown by double labeling of NPs and vimentin. Labeling for BNP was rather strong in the main trunks, major processes, but hardly detectable in the endfeet. The expression profile for ANP was similar, but with a much lower level. On the contrary, the endfeet and major processes in the inner retina were strongly CNP-positive, with the main trunks and other major processes in the outer retina much less labeled. These results raise a possibility that NPs, when released from Müller cells, may perform layer dependent functions.

Animals↗

PubMed2005

In vitro expression of natriuretic peptides in cardiomyocytes differentiated from monkey embryonic stem cells.

Functional characterization of ES cell-derived cardiomyocytes is important for differentiation control and application to the cell therapy. One of the crucial functions of cardiomyocytes is a production of atrial and brain natriuretic peptides (ANP and BNP, respectively), which have important endocrine, autocrine, and paracrine functions. In this study, we focused on the functional aspect of the cardiomyocytes differentiated from monkey ES cells in vitro and investigated the expression of ANP and BNP. Spontaneously contracting cells showed nodal-like action potentials, and expression of ANP and BNP by RT-PCR and immunocytochemistry. Interestingly, ANP and BNP expressions were detected as immunoreactive granules in the perinuclear area and these signals appeared to co-localize with trans-Golgi network. These findings suggest that monkey ES cells were able to differentiate into cardiomyocytes with functional characteristics in vitro and therefore can be used as a useful model to study mechanisms and functions in early cardiogenesis.

Action Potentials↗

PubMed1992

Cocaine self-administration differentially alters mRNA expression of striatal peptides.

The influence of cocaine self-administration on the expression of messenger RNAs for dynorphin, enkephalin and substance P was analyzed in the rat striatum with in situ hybridization histochemistry. Cocaine, an indirect dopamine agonist, was found to differentially affect the levels of mRNA encoding these neuropeptides in different subregions of the striatum. Following a 7 day period of variable free access to cocaine, dynorphin and substance P mRNA levels were elevated throughout the striatum, but the increases were substantially greater in the dorsal striatum than in the nucleus accumbens. Enkephalin mRNA was not significantly altered in the dorsal striatum but was slightly elevated in the nucleus accumbens. These results suggest that cocaine self-administration has differential effects on striatonigral and striatopallidal projection neurons, and that these effects vary in subregions of the striatum.

Animals↗

PubMed1996

Peptide YY expression is an early event in colonic endocrine cell differentiation: evidence from normal and transgenic mice.

The hormone peptide YY is produced by endocrine cells in the pancreas, ileum and colon. We have previously shown that peptide YY is coexpressed in all four islet cell types in the murine pancreas when they first appear, suggesting a common peptide YY-producing progenitor. In the colon, peptide YY has been frequently identified in glucagon-expressing L-type endocrine cells. Characterization of colonic endocrine tumors in transgenic mice expressing simian virus 40 large T antigen under the control of the peptide YY gene 5' flanking region revealed tumor cells producing not only peptide YY and glucagon, but also neurotensin, cholecystokinin, substance P, serotonin, secretin, and gastrin. This suggested that multiple enteroendocrine lineages were related to peptide YY-producing cells. Subsequent examination of the ontogeny of colonic endocrine differentiation in nontransgenic mice revealed that peptide YY was the first hormone to appear during development, at embryonic day 15.5. Between embryonic days 16.5 and 18.5, cells expressing glucagon, cholecystokinin, substance P, serotonin, secretin, neurotensin, gastrin and somatostatin first appeared and peptide YY was coexpressed in each cell type at this time. Peptide YY coexpression continued in a significant fraction of most enteroendocrine cell types throughout fetal and postnatal development and into adulthood, with the exception of serotonin-producing cells. This latter population of cells expanded dramatically after birth with rare coexpression of peptide YY. These studies indicate that expression of peptide YY is an early event in colonic endocrine differentiation and support the existence of a common progenitor for all endocrine cells in the colon.

Animals↗

PubMed2005

Upstream regions of the estrogen receptor alpha proximal promoter transcript regulate ER protein expression through a translational mechanism.

Estrogen receptor alpha (ER) mRNA is primarily transcribed from two promoters, the two transcripts share identical sequence encoding the same ER protein but differ in upstream regions. The 5' region of the two transcripts contain upstream open reading frames (uORFs) encoding potential peptides of 20 and 18 amino acids. The peptides have five C-terminal residues in common. These studies were undertaken to determine if the uORFs and encoded peptides differentially affected expression of ER. Expression of green fluorescent protein (GFP) reporter constructs containing upstream proximal promoter transcript sequences with the first 18 codons of ER fused to GFP was tested in HeLa cells. The cells expressed reduced levels of GFP as compared to the pEGFP-N1 parent vector; the effect was dependent on the presence of an intact proximal ER transcript uORF. Similar regulation by the uORF was seen in transfected MCF-7, MDA MB-231 and Ishikawa cells. Only protein expression was affected by eliminating the uORF; RNA levels were unchanged. This indicates the mechanism is translational rather than being an effect of the introduced point mutations on either mRNA stability or transcription. Eliminating the uORF did not significantly increase expression from similar distal promoter transcript ER-GFP constructs. However, study of in-frame fusions of GFP to the entire proximal and distal uORFs and to their translational start motifs showed that the translational start region of the distal uORF was inherently better at initiating translation than the AUG environment of the proximal promoter transcript uORF. The data indicate there are regulatory properties suppressing expression from the ER translation start which are specific to the unique regions of the ER proximal promoter transcript and these are likely associated with the proximal transcript uORF peptide product.

5' Untranslated Regions↗

PubMed2005

Proteomic study of human bronchoalveolar lavage fluids from smokers with chronic obstructive pulmonary disease by combining surface-enhanced laser desorption/ionization-mass spectrometry profiling with mass spectrometric protein identification.

Bronchoalveolar lavage fluid (BALF) is an important diagnostic source to investigate cellular and molecular changes in the course of lung disorders. The pattern of soluble proteins in BALF obtained from patients at different stages of respiratory disorders may provide deeper insights in the molecular mechanisms of the disease. We used surface-enhanced laser desorption/ionization mass spectrometry (MS) for differential protein display combined with reversed-phase chromatography and subsequent matrix-assisted laser desorption/ionization-MS or nanoliquid chromatography MS/MS analysis for protein identification to compare the protein pattern of BALF samples obtained from ten smokers suffering from chronic obstructive pulmonary disease (COPD), eight clinically asymptomatic smokers, and eight nonsmokers without pulmonary disease. In this context, we were able to identify small proteins and peptides, either differentially expressed or secreted in the course of COPD or in a direct response to cigarette smoke. The concentrations of neutrophil defensins 1 and 2, S100A8 (calgranulin A), and S100A9 (calgranulin B) were elevated in BALFs of smokers with COPD when compared to asymptomatic smokers. Increased concentrations in S100A8 (Calgranulin A), salivary proline-rich peptide P-C, and lysozyme C were detected in BALFs of asymptomatic smokers when compared to nonsmokers, whereas salivary proline-rich peptide P-D and Clara cell phospholipid-binding protein (CC10) were reduced in their concentration. The identified proteins and peptides might be useful in the future as diagnostic markers for smoke-induced lung irritations and COPD.

Bronchoalveolar Lavage Fluid↗

PubMed1995

Differential gene expression of vascular natriuretic peptide receptor subtype in artery and vein.

Although the vasorelaxation by natriuretic peptide (NP) is much less potent in the vein than in the artery, mechanism underlying the phenomenon remains unknown. Since NP receptor consists of three subtypes with different functions, we determined the mRNA level of each NP receptor subtype in the artery and vein by ribonuclease protection assay. In the aorta, NP-A receptor related to the biological action of NP was the predominant form. By contrast, NP-C receptor related mainly to the clearance of NP was the predominant form in the inferior vena cava: NP-C mRNA level was about two fold higher than in the aorta, while both NP-A and NP-B receptor mRNA levels were about half of that in the aorta. These results provide the molecular basis for the different biological response to NP in the artery and vein. Differential gene expression of NP receptor subtype could be an important determinant of the biological actions of NP.

Animals↗

PubMed2001

Peptide elongation factor eEF1A-2/S1 expression in cultured differentiated myotubes and its protective effect against caspase-3-mediated apoptosis.

Peptide elongation factor eEF1A-2/S1, which shares 92% homology with eEF1A-1/EF-1alpha, is exclusively expressed in brain, heart, and skeletal muscle. In these tissues, eEF1A-2/S1 is the only type 1A elongation factor expressed in adulthood because a transition from eEF1A-1/EF-1alpha to eEF1A-2/S1 occurs in early postnatal development. In this article, we report that the expression of eEF1A-2/S1 protein is activated upon myogenic differentiation. Furthermore, we show that upon serum deprivation-induced apoptosis, eEF1A-2/S1 protein disappears and is replaced by its homolog eEF1A-1/EF-1alpha in dying myotubes; cell death is characterized by the activation of caspase-3. In addition, we show that the continuous expression of eEF1A-2/S1 resulting from adenoviral gene transfer protects differentiated myotubes from apoptosis by delaying their death, thus suggesting a prosurvival function for eEF1A-2/S1 in skeletal muscle. In contrast, myotube death is accelerated by the introduction of the homologous gene, eEF1A-1/EF-1alpha, whereas cells transfected with antisense eEF1A-1/EF-1alpha are protected from apoptosis. These results demonstrate that the two sister genes, eEF1A-1/EF-1alpha and eEF1A-2/S1, regulate myotube survival with the former exerting prodeath activity and the latter a prosurvival effect.

Adenoviridae↗

PubMed1995

Expression and differential regulation of natriuretic peptides in mouse macrophages.

The coexpression of the natriuretic peptides ANP, BNP and CNP as well as their differential regulation in mouse macrophages was demonstrated by quantitative PCR, HPLC analysis, and specific radioimmunoassays. Exposure of peritoneal- and bone marrow-derived macrophages to various immunomodulators revealed that bacterial LPS strikingly increases (up to 300-fold) the mRNA coding for CNP as does zymosan (up to 15-fold). In this respect, neither the phorbol ester PMA nor the glucocorticoid dexamethasone had any effect. Examination of macrophages for ANP mRNA showed a similar response to LPS and zymosan, though only a three- to sixfold increase, confirming previous data. In contrast, the concentration of mRNA coding for brain natriuretic peptide in these cells was reduced by dexamethasone (up to twofold) as well as LPS (two- to fivefold). No change was observed upon challenge with zymosan or PMA. The findings at the mRNA level are complemented by their corresponding peptide products. Incubation of macrophages with LPS resulted in a two- and fivefold elevation of intracellular ANP and CNP immunoreactivity, respectively. The amount of peptides released from cells under these conditions was found increased for ANP (threefold) and CNP (10-fold). No changes were observed for both intra- and extracellular brain natriuretic peptide. The coexpression of natriuretic peptides in macrophages as well as their different regulations by immunomodulators suggest discrete functions of these peptides within the immune system.

Animals↗

PubMed2001

Sexually dimorphic effects of testosterone on preoptic area calcitonin gene-related peptide mRNA expression depend upon neuron location and differential estrogen and androgen receptor activation.

Experiments examined activational roles of gonadal steroids on the sexually dimorphic, calcitonin gene-related peptide-expressing neurons of the rat preoptic area. Gonadectomy of male rats followed by treatment with testosterone, dihydrotestosterone, or estrogen demonstrated that the tonic suppressive influence of testosterone on cellular levels of calcitonin gene-related peptide mRNA expression in the medial preoptic nucleus and anteroventral periventricular nucleus occurred through either ER- or AR-mediated mechanisms (P < 0.05). The gonadectomy of adult female rats demonstrated little tonic influence of ovarian steroids upon calcitonin gene-related peptide mRNA levels. However, the administration of male levels of testosterone to ovariectomized rats resulted in reduced calcitonin gene-related peptide mRNA expression within the medial preoptic nucleus (P < 0.05) and, strikingly, a 3-fold induction in calcitonin gene-related peptide mRNA expression in the anteroventral periventricular nucleus (P < 0.01). Testosterone's effects in the medial preoptic nucleus and anteroventral periventricular nucleus of the female required both ER and AR activation. Dual labeling immunocytochemical studies revealed that less than 10% of calcitonin gene-related peptide neurons in the male expressed ARs compared with approximately 50% in the female. These investigations reveal that sexually differentiated region- and steroid receptor-specific mechanisms function in association with the sex differences in circulating gonadal steroids to maintain the sexually dimorphic nature of calcitonin gene-related peptide expression in the preoptic area of the adult rat.

Animals↗

PubMed1998

Activin A and follistatin influence expression of somatostatin in the ciliary ganglion in vivo.

An important developmental question concerns whether neurotransmitter phenotype is an inherent property of neurons or is influenced by target tissues. This issue can be addressed in the avian ciliary ganglion (CG) which contains two cholinergic populations, ciliary and choroid neurons, that differentially express the peptide cotransmitter, somatostatin. The present study tests the hypothesis that differences in the level of expression of activin A and its endogenous inhibitor follistatin in CG neuron target tissues are responsible for selective expression of somatostatin in choroid neurons. Intraocular injection of activin A or follistatin (300 ng injected at E10/E11) in cultured embryos resulted in a 39% increase or a 23% decrease, respectively, in somatostatin-positive neurons relative to controls. Chorioallantoic membrane application of follistatin (1 microgram daily from E7 to E13) reduced somatostatin positive neurons by 54%. Neuron number, size, and target tissue morphology were unaffected by these treatments. Together with our previous studies, these data suggest that activin A and follistatin are target-derived molecules that regulate neuropeptide phenotype in the ciliary ganglion.

Activins↗

PubMed1993

Mutants of Ustilago maydis defective in production of one of two polypeptides of KP6 toxin from the preprotoxin.

Double-stranded RNA viruses of Ustilago maydis encode secreted killer toxins to which other cells of the same species and closely related species are sensitive. KP6 toxin consists of two polypeptides, alpha and beta, produced from a single precursor preprotoxin. In this work, we cloned complementary DNA for the toxin-encoding segment of two of the KP6 nonkiller mutants NK3 and NK13 that secrete the beta and alpha polypeptides, respectively. Both sequence analysis of the cDNA clones and in vitro translation of the toxin-encoding double-stranded RNAs showed that both mutants can produce full-length preprotoxins. Cys51 in alpha is converted to Arg in NK3 and Thr25 and Lys42 in beta are changed to Pro and Arg, respectively, in NK13. Although alpha and beta are encoded in a single prepropolypeptide, only the beta polypeptide is secreted by NK3 and only the alpha polypeptide is secreted by NK13. This differential expression of peptides from one precursor is a unique phenomenon. Neither of the nonsecreted polypeptides accumulated in the cytosol. The possible effects of these mutations on preprotoxin folding and their consequences for toxin secretion are discussed.

Amino Acid Sequence↗

PubMed1999

Differential expression of mucins and trefoil peptides in native epithelium, Barrett's metaplasia and squamous cell carcinoma of the oesophagus.

BACKGROUND AND AIMS: In humans, trefoil peptides (TFF peptides) and some mucins have been reported to be expressed in a cell-specific manner at mucosal surfaces of normal gastrointestinal tissues. Neoplastic conditions cause characteristic changes of these expression patterns. To study such patterns in Barrett's metaplasia and squamous cell carcinoma of the oesophagus (SCC), the distribution of MUC1, MUC2, MUC5AC and the three TFF peptides (TFF1, TFF2 and TFF3) was investigated. METHODS: In 40 archival samples of SCC and in 21 samples of Barret's metaplasia, expression of the three mucins and two TFF peptides (TFF1 and TFF2) was assessed by specific antibodies. Reverse transcriptase/polymerase chain reaction amplification (RT-PCR) was performed on frozen tissue samples from the 11 biopsies of SCC for the three TFF peptides. RESULTS: Immunohistochemical tests for MUC2 and TFF2 were negative both in samples of Barret's metaplasia and in SCC. MUC1 expression was detected in 57.5% of the tumour samples, while TFF1 and MUC5AC were found in 10% and 7.5% of the cases respectively. In Barrett's metaplasia MUC1 was detected in 90.5% of the cases and TFF1 and MUC5AC in all of them. RT-PCR analysis revealed a more complex pattern: TFF1 and TFF3 expressed the corresponding mRNA in all samples investigated; the third member, TFF2, was active in 45.5% of the carcinoma biopsies and not in the corresponding native tissue. CONCLUSIONS: This finding in oesophageal carcinoma contrasts with the situation found in normal and neoplastic stomach epithelium where TFF1 and TFF2 are found co-expressed and TFF3 remains silent. Interestingly, MUC1 is expressed in a significant proportion of SCC. Both in Barett's metaplasia and in SCC the expression of MUC5AC mirrors the TFF1 synthesis in intensity and spatial distribution.

Adult↗

PubMed1998

Differential expression of the TFF-peptides xP1 and xP4 in the gastrointestinal tract of Xenopus laevis.

TFF-peptides (formerly P-domain peptides, trefoil factors) represent major secretory products of the mammalian gastrointestinal tract. A molecular cloning approach revealed the existence of two TFF-peptides, xP1 and xP4, also in the stomach of Xenopus laevis. Here, the localization of these two peptides by Western blot analysis as well as immunohistochemistry is presented. xP1 is found predominantly in the surface mucous cells of the stomach, whereas xP4 is mainly localized to a specific population of goblet cells in the esophagus, to mucous neck cells of the stomach, and to closely resembling cells in antral glands. xP4 in the esophagus and in the stomach differ by their N-glycosylation patterns. Compared to mammalian TFF-peptides, xP1 obviously represents the frog homologue of human TFF1 (formerly pS2) and xP4 seems to be the amphibian equivalent of human TFF2 (formerly hSP).

Animals↗

PubMed2025

Sex differences in cerebrospinal fluid proteomics of patients with restless legs syndrome.

STUDY OBJECTIVES: The pathobiology of restless legs syndrome (RLS) remains poorly understood, complicating effective treatment. This observational cross-sectional study aimed to identify a cerebrospinal fluid proteomic signature of RLS and to explore sex-specific differences in cerebrospinal fluid proteomics. METHODS: Cerebrospinal fluid samples were collected from 22 untreated RLS patients and 18 controls, matched for age, body mass index, and sex. Proteomic analysis was conducted using the SOMAscan platform, assessing over 7000 peptides. RESULTS: Eight proteins were differentially abundant between patients and controls, with CRP and JAML increased, and TAPBPL and IL1RL1 decreased. Pathway analysis highlighted significant involvement in immune response, coagulation, and cytoskeletal regulation. Analyses were then carried out using sex stratification, comparing men and women separately. Sex-specific analyses revealed more pronounced proteomic alterations in males (68 differentially abundant proteins vs. control males) than in females (17 proteins). Gene enrichment analysis revealed that men with RLS had more involvement in gene regulation and epigenetic factors than control males and women with restless legs syndrome had greater involvement in systemic inflammatory and vascular processes than control females. CONCLUSIONS: This study identified a cerebrospinal fluid proteomic signature in RLS, implicating immune and inflammatory pathways in the disease's pathophysiology. Significant sex differences in protein level suggest potential sex-specific mechanisms in RLS, warranting further investigation. These findings contribute to the current understanding of RLS and could inform future therapeutic strategies.

Humans↗