Biomedical subjects

Hannu Koistinen

Publications and source records attributed to Hannu Koistinen.

16 recordsLinked to original sources

PubMed2006

Cumulus oophorus-associated glycodelin-C displaces sperm-bound glycodelin-A and -F and stimulates spermatozoa-zona pellucida binding.

Spermatozoa have to swim through the oviduct and the cumulus oophorus before fertilization in vivo. In the oviduct, spermatozoa are exposed to glycodelin-A and -F that inhibit spermatozoa-zona pellucida binding. In this study, we determined whether these glycodelins would inhibit fertilization. The data showed that the spermatozoa without previous exposure to glycodelin-A and -F acquired glycodelin immunoreactivity during their passage through the cumulus oophorus. On the other hand, when glycodelin-A or -F-pretreated spermatozoa were exposed to the cumulus oophorus, the zona pellucida binding inhibitory activity of glycodelin-A and -F was not only removed, but the spermatozoa acquired enhanced zona pellucida binding ability. These actions of the cumulus oophorus were due to the presence of a cumulus isoform of glycodelin, designated as glycodelin-C. The cumulus cells could convert exogenous glycodelin-A and -F to glycodelin-C, which was then released into the surrounding medium. The protein core of glycodelin-C was identical to that in other glycodelin isoforms, as demonstrated by mass spectrum, peptide mapping, and affinity to anti-glycodelin antibody recognizing the protein core of glycodelin. In addition to having a smaller size and a higher isoelectric point, glycodelin-C also had lectin binding properties different from other isoforms. Glycodelin-C stimulated spermatozoazona pellucida binding in a dose-dependent manner, and it effectively displaced sperm-bound glycodelin-A and -F. In conclusion, the cumulus cells transform glycodelin-A and -F to glycodelin-C, which in turn removes the spermatozoazona binding inhibitory glycodelin isoforms and enhances the zona binding capacity of spermatozoa passing through the cumulus oophorus.

Female↗

PubMed2006

Glycodelin-A interacts with fucosyltransferase on human sperm plasma membrane to inhibit spermatozoa-zona pellucida binding.

Fertilization depends on successful binding of the spermatozoa to the zona pellucida of the oocyte. Glycodelin-A inhibits spermatozoa-zona pellucida binding. Previous data showed that glycodelin-A receptor(s) and zona pellucida protein receptor(s) on human spermatozoa are closely related. Using a chemical cross-linking approach, the glycodelin-A-sperm receptor complex was isolated. The receptor was identified to be fucosyltransferase-5 (FUT5) by mass spectrometry and confirmed with the use of anti-FUT5 antibodies. Sperm FUT5 was an externally oriented integral membrane protein in the acrosomal region of human spermatozoa. Biologically active FUT5 was purified from spermatozoa. Co-immunoprecipitation confirmed the interaction between glycodelin-A and sperm FUT5. Solubilized zona pellucida reduced the binding of glycodelin-A to sperm FUT5. An anti-FUT5 antibody and FUT5 acceptor blocked the binding of glycodelin-A to spermatozoa and the zona binding inhibitory activity of glycodelin-A. Sperm FUT5 bound strongly to intact and solubilized human zona pellucida. The equilibrium dissociation constant of sperm FUT5 binding to solubilized zona pellucida was 42.82 pmol/ml. These observations suggest that human sperm FUT5 is a receptor of glycodelin-A and zona pellucida proteins, and that glycodelin-A inhibits spermatozoa-zona binding by blocking the binding of sperm FUT5 to the zona pellucida.

Antibodies↗

PubMed2006

Novel peptide inhibitors of human kallikrein 2.

Human kallikrein 2 (hK2) is a serine protease produced by the secretory epithelial cells in the prostate. Because hK2 activates several factors participating in proteolytic cascades that may mediate metastasis of prostate cancer, modulation of the activity of hK2 is a potential way of preventing tumor growth and metastasis. Furthermore, specific ligands for hK2 are potentially useful for targeting and imaging of prostate cancer and for assay development. We have used enzymatically active recombinant hK2 captured by a monoclonal antibody exposing the active site of the enzyme to screen phage display peptide libraries. Using libraries expressing 10 or 11 amino acids long linear peptides, we identified six different peptides binding to hK2. Three of these were shown to be specific and efficient inhibitors of the enzymatic activity of hK2 toward a peptide substrate. Furthermore, the peptides inhibited the activation of the proform of prostate-specific antigen by hK2. Amino acid substitution analyses revealed that motifs of six amino acids were required for the inhibitory activity. These peptides are potentially useful for treatment and targeting of prostate cancer.

Amino Acid Sequence↗

PubMed2006

Extracellular matrix-induced changes in expression of cell cycle-related proteins and proteasome components in endometrial adenocarcinoma cells.

OBJECTIVE: Extracellular matrix (ECM) components regulate growth and differentiation of epithelial cells, and impaired cell-ECM interaction may lead to increased cell proliferation and tumorigenesis. Whereas ECM has been shown to alter cellular morphology and reduce proliferation of HEC-1B endometrial adenocarcinoma cells, little is known about the underlying changes in gene expression. The purpose of this study was to investigate these changes. METHODS: We studied by cDNA array the effects of ECM components, as present in Matrigel basement membrane cell culture matrix, on gene expression in HEC-1B endometrial adenocarcinoma cells in respect of the same cells cultured on conventional plastic surface. Some of the changes were confirmed by protein analyses. RESULTS: As expected, several growth-promoting genes were downregulated, while many genes associated with growth restriction were upregulated in Matrigel-grown carcinoma cells. Also, the expression of many 20S proteasome components was downregulated. The observed changes point to a less malignant phenotype of Matrigel-grown tumor cells, supported by reduced growth characteristics and morphology. CONCLUSION: The study provides further insight into the mechanisms whereby ECM components may participate in the regulation of cell growth--by reducing expression of growth-promoting genes and increasing expression of the genes associated with growth restriction.

Adenocarcinoma↗

PubMed2006

Roles of glycodelin in modulating sperm function.

Glycodelin is a glycoprotein with three well-defined isoforms. They are named as glycodelin-S, glycodelin-A and glycodelin-F. The three isoforms have similar protein core but different carbohydrate moieties. Glycodelin-S is abundant in the human seminal plasma. It suppresses sperm capacitation and in doing so, it maintains the spermatozoa in an uncapacitated state before they enter into the uterine cavity. Glycodelin-A is abundant in the amniotic fluid. It is also secreted from endometrial glands into uterine fluid and is produced by the fallopian tube. Glycodelin-A is the first endogenous glycoprotein that was found to inhibit the binding of spermatozoa to the zona pellucida. The immunosuppressive properties of glycodelin-A suggest that the molecule may protect the spermatozoa from immune attack in the maternal reproductive tract. Glycodelin-F was first found in the follicular fluid, hence its name. It also inhibits spermatozoa-zona pellucida binding. In addition, glycodelin-F suppresses progesterone-induced acrosome reaction, and may serve to prevent premature acrosome reaction. Preliminary findings suggest possible presence of yet another glycodelin isoform in the extracellular matrix of cumulus oophorus. Unlike glycodelin-A and -F, it stimulates spermatozoa-zona pellucida binding. In summary, different isoforms of glycodelin have different biological roles on sperm function, and they act in succession to contribute to the success of fertilization.

Female↗

PubMed2006

Elevated levels of amyloid precursor protein in muscle of patients with amyotrophic lateral sclerosis and a mouse model of the disease.

Amyotrophic lateral sclerosis (ALS) is a progressive neurodegenerative disease defined by motor neuron loss. Transgenic mouse models show features that closely mimic those seen in the clinical situation, reflected in the molecular changes observed in mouse models and in tissues from patients. We report a dramatic increase in the expression of amyloid precursor protein (APP) in the hindlimb muscles, but not the spinal cord of the G93A transgenic mouse model, significantly before the appearance of clinical abnormalities. APP levels were unchanged in nontransgenic mice and in mice overexpressing human wild-type Cu/Zn-dependent superoxide dismutase 1 (SOD1). Preliminary results indicate a similar change in APP expression in human deltoid muscle samples from ALS patients compared with age-matched controls. The inhibitory role of APP in innervation at the neuromuscular junction and increased expression in inclusion-body myositis suggest that presymptomatic upregulation of APP may be consistent with a potential role for APP in ALS pathology.

Adult↗

PubMed2006

A sensitive proximity ligation assay for active PSA.

Prostate-specific antigen (PSA) is a widely used marker for prostate cancer. The utility of PSA tests is limited by their inability to differentiate prostate cancer from non-malignant conditions such as benign prostatic hyperplasia and prostatitis. In circulation, PSA occurs in various complexed and free forms, and specific determination of some of these can be used to improve the diagnostic accuracy of PSA tests. We have previously identified peptides that specifically bind to enzymatically active PSA and using such a peptide we have developed an immunopeptidometric assay for this form of PSA. However, the sensitivity of that assay is too low to measure active PSA at clinically important levels. Recently a novel sensitive immunoassay for analysis of proteins, termed the proximity ligation assay, has been established. Here we describe a sensitive implementation of the proximity ligation assay, which utilizes a PSA-binding peptide and antibody as probes to detect active PSA. The assay has a sensitivity of 0.07 microg/l, which is approximately ten-fold lower than that of our previous assay. It does not cross-react with inactive proPSA or the highly similar kallikrein hK2. Our results show that a highly sensitive immunopeptidometric assay can be developed using proximity ligation. This principle should facilitate establishment of specific assays for active forms of other proteases.

Antibody Specificity↗

PubMed2006

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Journal Article↗

PubMed2005

Glycodelin-S in human seminal plasma reduces cholesterol efflux and inhibits capacitation of spermatozoa.

Tight control of sperm capacitation is important for successful fertilization. Glycodelin-S is one of the most abundant glycoproteins in the human seminal plasma. However, its function is unclear. We investigated the role of glycodelin-S on capacitation of human spermatozoa. Binding kinetics experiments demonstrated the presence of two saturable and reversible binding sites of glycodelin-S on human spermatozoa. Differently glycosylated other isoforms of glycodelin, glycodelin-A and -F, did not compete with glycodelin-S for these binding sites, suggesting that the glycodelin-S binding sites are different from those of the other isoforms. Indirect immunofluorescent staining revealed specific binding of glycodelin-S around the sperm head. This immunoreactivity was greatly reduced in spermatozoa that had migrated through the cervical mucus surrogates. Glycodelin-S at physiological concentrations significantly reduced the bovine serum albumin and cyclodextrin-induced cholesterol efflux and down-regulated the adenylyl cyclase/protein kinase A/tyrosine kinase signaling pathway, resulting in suppression of capacitation. Deglycosylation abolished glycodelin-S binding and the effect of glycodelin-S on bovine serum albumin-induced capacitation. This indicates that the carbohydrate moiety of glycodelin-S is critical for the function of the molecule. It is concluded that glycodelin-S in seminal plasma maintains the uncapacitated state of human spermatozoa.

Acrosome↗

PubMed2005

Glycodelin reduces carcinoma-associated gene expression in endometrial adenocarcinoma cells.

OBJECTIVE: Glycodelin is a major secretory glycoprotein of differentiated endometrial epithelium, rarely expressed in proliferative endometrium or endometrial cancer. We aimed to elucidate its role in growth and gene expression of endometrial adenocarcinoma cells, and hypothesized that glycodelin affects cell growth and tumor-associated gene expression. STUDY DESIGN: Endometrial adenocarcinoma HEC-1B cells were transfected with glycodelin cDNA in both antisense and sense orientations. Cellular morphology, cell proliferation, and gene expression were compared between native and transfected cells. RESULTS: Compared with native and antisense-transfected carcinoma cells, sense-transfected, glycodelin-producing carcinoma cells showed reduced proliferation, morphologic changes, and altered expression of cancer-related genes. Notably, anti-apoptotic Bcl-XL and MUC1 genes were down-regulated. CONCLUSION: Reduction by glycodelin transfection of carcinoma cell proliferation and expression of MUC1 and Bcl-XL is significant because these genes are often overexpressed in human cancers--MUC1 is linked to invasive growth and metastases, and both confer resistance to chemotherapy. These results suggest a novel mechanism whereby malignant growth of endometrial adenocarcinoma cells is regulated.

Adenocarcinoma↗

PubMed2005

Late follicular phase administration of levonorgestrel as an emergency contraceptive changes the secretory pattern of glycodelin in serum and endometrium during the luteal phase of the menstrual cycle.

This study examined serum glycodelin concentrations and endometrial expression during the luteal phase following oral administration of levonorgestrel (LNG) at different stages of the ovarian cycle. Thirty women were recruited and allocated into three groups. All groups were studied during two consecutive cycles, a control cycle and the treatment cycle. In the treatment cycle, each woman received two doses of 0.75 mg LNG taken 12 h apart on days 3-4 before the luteinizing hormone (LH) surge (Group 1), at the time of LH rise (Group 2) and 48 h after the rise in LH was detected (Group 3). Serum progesterone (P) and glycodelin were measured daily during the luteal phase, and an endometrial biopsy was taken at day LH +9 for immunohistochemical glycodelin-A staining. In Group 1, serum P levels were significantly lower, serum glycodelin levels rose earlier and endometrial glycodelin-A expression was weaker than in Groups 2 and 3, in which no differences were found between control and treatment cycles. Levonorgestrel taken for emergency contraception (EC) prior to the LH surge alters the luteal phase secretory pattern of glycodelin in serum and endometrium. Based on the potent gamete adhesion inhibitory activity of glycodelin-A, the results may account for the action of LNG in EC in those women who take LNG before the LH surge.

Adult↗

PubMed2003

Differences in glycosylation and sperm-egg binding inhibition of pregnancy-related glycodelin.

Glycodelin is a glycoprotein produced in many glands, particularly those of reproductive tissues. It appears as different glycoforms in amniotic fluid (glycodelin-A) and seminal plasma (glycodelin-S), but only glycodelin-A inhibits gamete adhesion. In the present study, glycodelin from secretory-phase endometrium, first-trimester pregnancy decidua, and midtrimester amniotic fluid was studied with respect to physicochemical properties, including glycosylation patterns and inhibitory activity of sperm-egg binding. Purified glycodelins from all these sources were similar in isoelectric focusing and in lectin immunoassays using lectins from Wisteria floribunda and Sambucus nigra. Likewise, the glycodelins inhibited sperm-egg binding in a dose-dependent manner, as measured by hemizona-binding assay. However, subtle quantitative physicochemical and biological differences were found between glycodelins from different sources as well as within the same tissue/fluid between different individuals. Differences were most pronounced between endometrial glycodelins from nonpregnancy and first-trimester pregnancy. The glycan structures studied by fast-atom bombardment mass spectrometry of individual amniotic fluid glycodelin-A samples also showed interindividual quantitative differences. In conclusion, glycodelins from different female reproductive tract tissues and amniotic fluid share substantial similarity, allowing all of them to be called glycodelin-A. However, these glycodelins exhibit quantitative physicochemical and functional differences between different sources and individuals.

Adult↗

PubMed2003

Binding of zona binding inhibitory factor-1 (ZIF-1) from human follicular fluid on spermatozoa.

Previous studies showed that zona binding inhibitory factor-1 (ZIF-1) was the glycoprotein mainly responsible for the spermatozoa zona binding inhibitory activity of human follicular fluid. ZIF-1 has a number of properties similar to glycodelin-A. A binding kinetics experiment in the present study demonstrated the presence of two binding sites of ZIF-1 on human spermatozoa. These binding sites were saturable, reversible, and bound to (125)I-ZIF-1 in a time-, concentration-, and temperature-dependent manner. Glycodelin-A shared one common binding site with ZIF-1 on spermatozoa, and it could displace only 70% of the (125)I-ZIF-1 bound on human spermatozoa. ZIF-1 and glycodelin-A formed complexes with the soluble extract of human spermatozoa. Coincubation of solubilized zona pellucida proteins reduced the binding of ZIF-1 to two complexes of the extract, suggesting that the ZIF-1 binding sites and zona pellucida protein receptors on human spermatozoa were closely related. ZIF-1, but not glycodelin-A, significantly suppressed progesterone-induced acrosome reaction of human spermatozoa. The carbohydrate moieties derived from ZIF-1 reduced the binding of native ZIF-1 on human spermatozoa as well as the zona binding inhibitory activity of the glycoprotein, although the intensity of the effects are lower when compared with the native protein. These effects are not due to the action of the molecules on the motility, viability, and acrosomal status of the treated spermatozoa. Deglycosylated ZIF-1 had no inhibitory effect on both ZIF-1 binding and zona binding capacity of spermatozoa. We concluded that the carbohydrate part of ZIF-1 was critical for the functioning of the glycoprotein.

Acrosome Reaction↗

PubMed2002

Prostate-specific antigen and other prostate-derived proteases cleave IGFBP-3, but prostate cancer is not associated with proteolytically cleaved circulating IGFBP-3.

BACKGROUND: Proteolysis of insulin-like growth factor-binding proteins (IGFBPs) may increase IGF-mediated growth stimulation and development of cancer in the organs producing large amounts of proteases, such as the prostate. METHODS: We studied proteolysis of IGFBP-3 by three prostate-derived proteases, namely prostate specific antigen (PSA), human kallikrein 2 (hK2), and trypsin, and also by native seminal plasma. Cleavage of 125I-IGFBP-3 was studied by SDS-PAGE and autoradiography. We also used two different sandwich-type IGFBP-3 immunoassays, called "intact" and "total" IGFBP-3 assays. These assays differ in their capacity to recognize proteolytically degraded IGFBP-3. RESULTS: HK2, PSA, and trypsin all cleaved IGFBP-3 at the concentrations normally present in seminal plasma. The IGFBP-3 cleavage by seminal plasma was inhibited by ZnCl2, which strongly inhibits hK2 and PSA, but not by a specific trypsin inhibitor. The IGFBP-3 fragments resulting from proteolytic cleavage by PSA, hK2, or trypsin were undetectable in the "intact IGFBP-3 assay," whereas the "total IGFBP-3 assay" also detected the proteolytic fragments. No increased fragmentation of IGFBP-3 was found in serum of 659 men with elevated PSA concentrations, of whom 178 had a proven prostate cancer. Furthermore, the IGFBP-3 levels were not associated with the PSA concentrations. CONCLUSIONS: These results show that, while seminal plasma and prostate-derived proteases can cleave IGFBP-3, in patients with prostate cancer the circulating IGFBP-3 is not significantly proteolyzed by either PSA, hK2, or trypsin.

Cell Division↗

PubMed2002

Monoclonal antibodies, immunofluorometric assay, and detection of human semenogelin in male reproductive tract: no association with in vitro fertilizing capacity of sperm.

Semenogelin plays an important role in sperm clotting and is degraded into smaller fragments by prostate-specific antigen (PSA) during clot liquefaction. Semenogelin and its fragments inhibit sperm motility in vitro. We studied the expression of semenogelin I mRNA and its localization in various tissues of the male genital tract. We also studied semenogelin concentrations with respect to sperm parameters and the outcome of in vitro fertilization. Semenogelin protein was detected by immunohistochemical staining and semenogelin I mRNA was detected by Northern blot analysis in the seminal vesicles and ampullary part of the vas deferens, whereas specimens from the prostate, epididymis, testis, and the female genital tract were negative. Using monoclonal antibodies against semenogelin, an immunofluorometric assay was developed to measure semenogelin levels in seminal plasma and to evaluate possible correlations with sperm parameters and fertilization in vitro. No correlation was found between the semenogelin concentration and the volume of the ejaculate, sperm concentration, sperm motility, or in vitro fertilization rate. Semenogelin levels were positively correlated with the total protein concentration in seminal plasma, and there was an inverse correlation between the concentration of semenogelin and that of PSA. The levels of semenogelin appear to bear no relationship to the in vitro fertilization capacity of the spermatozoa.

Adult↗

PubMed2002

Glycodelin: a major lipocalin protein of the reproductive axis with diverse actions in cell recognition and differentiation.

Glycodelin is a glycoprotein that belongs to the lipocalin superfamily. Depending on glycosylation, glycodelin appears in various isoforms. In the uterus, glycodelin-A is the major progesterone-regulated glycoprotein secreted into uterine luminal cavity by secretory/decidualized endometrial glands. The other tissues expressing glycodelin include fallopian tubes, ovary, breast, seminal vesicle, bone marrow, and eccrine glands. Glycodelin-A potently and dose-dependently inhibits human sperm-egg binding, whereas differently glycosylated glycodelin-S from seminal plasma has no such effect. Absence of contraceptive glycodelin-A in the uterus during periovulatory midcycle is consistent with an open "fertile window." Glycodelin induced by local or systemic administration of progestogens may potentially reduce the fertilizing capacity of sperm in any phase of the menstrual cycle. Glycodelin also has immunosuppressive activity. Its high concentration at the fetomaternal interface may contribute to protection of the embryonic semiallograft. Besides being an epithelial differentiation marker, glycodelin appears to play a role in glandular morphogenesis, as transfection of glycodelin cDNA into a glycodelin-negative breast cancer cells resulted in formation of gland-like structures, restricted proliferation, and induction of other epithelial markers. These various properties, as well as the chemistry, biology, and clinical aspects of glycodelin, continue to be areas of active investigation reviewed in this communication.

Cell Differentiation↗