Gelatinolytic and caseinolytic proteinase activities in human prostatic secretions

Restoration of the apoptosis pathways' proteins levels after orchiectomy in testicular tumour patients

Seminal plasma proteins already demonstrated to reflect the testicular environment function and important regulatory mechanisms. However, it is crucial to understand which of these proteins participate in probable altered pathways in testicular germ cell tumours and after unilateral orchiectomy. In this study, we proposed to verify, by a multiplex approach, the levels of DNA damage and apoptosis pathways' proteins, in seminal plasma of men before and after unilateral orchiectomy, and also in control men. Comparing pre- and post-orchiectomy groups, just the apoptosis pathways' proteins presented different levels, in which Bad was lower and Bcl2, Akt, caspase-9, p53 and caspase-8 were higher after orchiectomy. When comparing pre- and post-orchiectomy groups with control, both presented lower levels of ChK1, Chk2, H2AX, p53 and p21, for DNA damage pathway. Regarding the apoptosis pathway, lower levels of JNK, Bcl2, Akt, caspase-9, p53 and caspase-8 and higher levels of Bad were observed before orchiectomy. The post-orchiectomy group did not differ from controls, demonstrating a probable restoration on its proteins levels. We can conclude that testicular tumours can alter both of the assessed pathways, and its removal is associated with a probable restoration of the apoptosis pathway.

Matrix metallopeptidase expression and modulation by transforming growth factor-β1 in equine endometrosis

Equine endometrial fibrosis (endometrosis) is described as a degenerative chronic condition in the uterus. Its characteristic feature is excessive deposition of extracellular matrix (ECM) components around the endometrial glands and stroma. Although matrix metallopeptidases (MMPs) that mediate ECM turnover are important factors in the process of fibrosis, knowledge of their expression and regulation in endometrosis is limited. In other species, one of the important regulators of MMPs and tissue inhibitors of MMPs (TIMPs) is transforming growth factor (TGF)-β1. The goal of this study was to determine (i) endometrial expression of MMPs and TIMPs during endometrosis and (ii) the effect of TGF-β1 on expression of MMPs and TIMPs in equine endometrial fibroblasts and epithelial cells. In the follicular phase of the estrous cycle, MMP-1, -2, -9, and TIMP concentrations were higher during endometrosis than in healthy endometrium (P < 0.05). In the midluteal phase, MMP-3 concentration was lower in severe endometrosis compared to healthy endometrium (P < 0.05). In fibroblasts, TGF-β1 upregulated MMP-1, -9, -13, and TIMP1, but downregulated MMP-3 secretion (P < 0.05). In epithelial cells, TGF-β1 upregulated MMP-1, -9, -13, and TIMP secretion (P < 0.05). Endometrial expression of MMPs and TIMPs is altered during endometrosis. TGF-β1 is a regulator of endometrial ECM remodeling via its effect on MMPs and TIMPs in equine endometrial fibroblasts and epithelial cells.

Semen levels of matrix metalloproteinase (MMP) and tissue inhibitor of metallorproteinases (TIMP) protein families members in men with high and low sperm DNA fragmentation

Matrix Metalloproteinases (MMPs) and their regulators – Tissue Inhibitors of Matrix Metalloproteinases (TIMPs) – participate in extracellular matrix remodeling, fibrosis, and semen liquefaction, as well as to inflammatory activity. Seminal plasma has been shown to contain MMPs (MMP-2 and MMP-9) and TIMPs (TIMP-1 and TIMP-2). Also, a link between MMPs gene expression and excessive reactive oxygen species (ROS) has been established. In semen, ROS are associated with altered sperm function and increased DNA fragmentation. In this study, it is hypothesized that seminal MMPs and TIMPs levels are associated with sperm DNA fragmentation due to the fact that MMPs have been associated with semen quality. We also hypothesized that these proteins could predict DNA fragmentation status in sperm. Therefore, this study set out to verify if sperm DNA fragmentation levels relate to seminal levels of members of the MMP and TIMP protein families. The High sperm DNA fragmentation group presented lower seminal plasma levels of MMP-2, MMP-7, TIMP-1, TIMP-2 and TIMP-4 when compared to Low sperm DNA fragmentation group. Also, samples in the high sperm DNA fragmentation group presented higher acrosome integrity and lower mitochondrial activity levels when compared to low sperm DNA fragmentation samples. In the logistic regression analysis, MMP-2, MMP-7, and TIMP-4 classified samples as low and high sperm DNA fragmentation, with an overall model fit of 74.5%. Results from this study may demonstrate a specific inflammatory mechanism in samples with high sperm DNA fragmentation. This, in turn, can lead to the development of new studies regarding this mechanism and, in the future, create an opportunity to treat these patients for sperm DNA fragmentation by treating inflammatory seminal activity.

Substrate specificity of proteolytic activity in the testes fluid and seminal plasma of the common carp Cyprinus carpio

Substrate specificity in the seminal plasma and testes fluids of the common carp Cyprinus carpio was determined using gelatin, casein, albumin and haemoglobin. Proteolytic profiles of the testes and seminal plasma were compared. Different ranges of pH (5·5-9·5) and temperature (4-37° C) were used during incubations of seminal plasma proteinases. Differences in proteolytic activity between testes and seminal plasma may reflect specific functions of the testes and sperm ducts in semen production. Seminal plasma metalloproteinases were characterized by higher substrate specificity than were serine proteinases. Zymography optimization for seminal plasma indicated that pH 7·5 and 22° C were the optimal conditions for gel incubations.

MMP-2 and MMP-9 activities and TIMP-1 and TIMP-2 expression in the prostatic tissue of two ethanol-preferring rat models

We investigated whether chronic ethanol intake is capable of altering the MMP-2 and MMP-9 activities and TIMP-2 and TIMP-1 expression in the dorsal and lateral prostatic lobes of low (UChA) and high (UChB) ethanol-preferring rats. MMP-2 and MMP-9 activities and TIMP-1 and TIMP-2 expression were significantly reduced in the lateral prostatic lobe of the ethanol drinking animals. Dorsal prostatic lobe was less affected showing no significant alterations in these proteins, except for a reduction in the TIMP-1 expression in UChA rats. These important findings demonstrate that chronic ethanol intake impairs the physiological balance of the prostate extracellular matrix turnover, through downregulation of MMPs, which may contribute to the development of prostatic diseases. Furthermore, since these proteins are also components of prostate secretion, the negative impact of chronic ethanol intake on fertility may also involve reduction of MMPs and TIMPs in the seminal fluid.

Proteomic characterization and cross species comparison of mammalian seminal plasma

Seminal plasma contains a large protein component which has been implicated in the function, transit and survival of spermatozoa within the female reproductive tract. However, the identity of the majority of these proteins remains unknown and a direct comparison between the major domestic mammalian species has yet to be made. As such, the present study characterized and compared the seminal plasma proteomes of cattle, horse, sheep, pig, goat, camel and alpaca. GeLC-MS/MS and shotgun proteomic analysis by 2D-LC-MS/MS identified a total of 302 proteins in the seminal plasma of the chosen mammalian species. Nucleobindin 1 and RSVP14, a member of the BSP (binder of sperm protein) family, were identified in all species. Beta nerve growth factor (bNGF), previously identified as an ovulation inducing factor in alpacas and llamas, was identified in this study in alpaca and camel (induced ovulators), cattle, sheep and horse (spontaneous ovulators) seminal plasma. These findings indicate that while the mammalian species studied have common ancestry as ungulates, their seminal plasma is divergent in protein composition, which may explain variation in reproductive capacity and function. The identification of major specific proteins within seminal plasma facilitates future investigation of the role of each protein in mammalian reproduction.

BIOLOGICAL SIGNIFICANCE

This proteomic study is the first study to compare the protein composition of seminal plasma from seven mammalian species including two camelid species. Beta nerve growth factor, previously described as the ovulation inducing factor in camelids is shown to be the major protein in alpaca and camel seminal plasma and also present in small amounts in bull, ram, and horse seminal plasma.

Detection of matrix metalloproteinase (MMP)-2 and MMP-9 in canine seminal plasma

Matrix metalloproteinases (MMPs) are a family of proteolytic enzymes that play a central role in degradation of protein components of the extracellular matrix and basement membrane. Previous studies have shown that MMP-2 and MMP-9 are present in human seminal plasma, but there is little information available on the presence of MMPs in canine seminal plasma. This study aims to investigate the presence of MMPs in canine seminal plasma and their clinical manifestation at the level of various semen parameters in canine species. Latent and active forms of MMP-2 and MMP-9 were evaluated using gelatin zymography and their association with semen parameters was examined. Results demonstrate that both latent and active forms of MMP-2 and MMP-9 are present in canine seminal plasma and the latent forms are predominant. The latent and active MMP-9 activities were elevated in the semen with unsatisfactory quality traits and proMMP-2 was inversely correlated with semen quality whereas, MMP-2 was positively correlated with semen quality traits. These findings suggest that proMMP-9 and MMP-9 activation contributes to the variation in semen, while the activation of MMP-2 improves the sperm functionality.

Matrix metalloproteinase (MMP)-2 and MMP-9 activity and localization during ventral prostate atrophy and regrowth

Matrix metalloproteinses (MMPs) are enzymes involved in prostatic development, growth, disease-induced tissue remodelling and secretory fluid. Although the prostate function depends upon androgen regulation, the relationship between MMPs and androgen has not been well established. Here, we evaluated MMP-2 and MMP-9 gelatinolytic activity in association with tissue localization during ventral prostate atrophy and regrowth induced by testosterone replacement (TR). Adult male Wistar rats were divided into three experimental groups: control, castrated (CS) and TR 21 days after castration. Ventral prostate (VP) was excised at 3, 5, 7 and 21 days after castration in CS group, and at 3, 5, 7 and 10 days after TR (4 mg/kg/day) in TR group. The VP was dissected, weighed and processed for histology, immunohistochemistry, ultrastructure and zymography analyses. Castration elicited the typical parenchymal atrophy and stromal condensation. TR induced intense epithelial growth towards the stromal space to restore the prostate histoarchitecture. MMP-2 and MMP-9 immunostaining presented intense reaction in CS and TR groups, mainly in the epithelial and endothelial cells. After TR, a strong immunoreaction for MMP-2 was observed in the activated stromal fibroblasts. Zymography showed that MMP-2 and MMP-9 activity, mainly the active form, increased after castration. In contrast, TR induced an additional increase in MMP-2 activity, but not in MMP-9. In conclusion, the overall behaviour of MMP-2 and MMP-9 within the prostate under androgen handling is highly complex, as each glandular compartment and cell type is affected differently by the androgenic status. Prostate regrowth appears to involve a more effective participation of MMP-2 in both epithelial and stromal compartments, while MMP-9 plays a major role in the late prostate atrophy and early regrowth.

Matrix metalloproteinase (MMP)-2 and MMP-9 in seminal plasma

PURPOSE

To evaluate the latent and active forms of MMP-2 and MMP-9 in human semen samples and to investigate their association with semen parameters.

METHODS

Basic semen analysis was performed in 82 semen samples. Seminal plasma was analyzed with gelatin zymography.

RESULTS

Both latent and active forms of MMP-2 and MMP-9 were detected in human seminal plasma. The latent forms were the predominant ones. MMP-2 and MMP-9, either in latent or active forms, were not correlated with semen parameters. ProMMP-9 levels were higher in semen samples with abnormally low concentration (< or = 19 x 10(6)/ml) compared with semen samples with concentration > or = 50 x 10(6)/ml.

CONCLUSION

MMP-2 and MMP-9 are both present in human semen. The latent forms of both MMPs are the predominant ones. ProMMP-9 is elevated in samples of low sperm concentration.

Terazosin Modifies the Content of Glycosaminoglycans and the Activity of Matrix Metalloproteinase 2 in the Rat Ventral Prostate

OBJECTIVES

We have investigated the effects of terazosin on the content of glycosaminoglycans (GAGs), the activity of matrix metalloproteinase 2 (MMP-2) and MMP-9, and the content of tissue inhibitors of MMP (TIMP) in the ventral prostate of Wistar rats.

METHODS

Rats were treated with terazosin (0.12, 1.2mg/kg orally every second day) for 120 d. GAGs were isolated and purified from ventral prostate homogenates by lipid extraction, ethanol precipitation, and extensive digestion with pronase and DNAse, separated by electrophoresis, and characterised using specific enzymes. The activity of MMP-2 and MMP-9 was estimated using gelatin zymography and TIMP-1 and TIMP-2 were measured by enzyme-linked immunosorbent assay.

RESULTS

Terazosin treatment did not affect the weight of the ventral prostate gland. The prostate contains hyaluronic acid, chondroitin sulfate (CS), dermatan sulfate (DS), and heparan sulfate (HS), MMP-2, TIMP-1, and TIMP-2, but not MMP-9. Terazosin caused a significant increase in the relative content of DS and a significant decrease in the relative content of CS and to a lesser extent of HS. Terazosin evoked a significant increase in the activity of proMMP-2 and MMP-2 but did not affect TIMP.

CONCLUSIONS

The differential effect of terazosin treatment in GAG molecules of the rat prostate may be beneficial because CS is known to induce and DS to inhibit cell proliferation. The effect of terazosin on GAGs and MMP-2 may contribute in the molecular mechanisms of terazosin-induced apoptosis because HS and CS have a proapoptotic effect, whereas DS and MMP-2 are antiapoptotic.

Gelatinases and serine proteinase inhibitors of seminal plasma and the reproductive tract of turkey (Meleagris gallopavo)

This study examined proteolytic enzymes and serine proteinase inhibitors in turkey seminal plasma with relation to their distribution within the reproductive tract and to yellow semen syndrome (YSS). Proteases of blood plasma, extracts from the reproductive tract, and seminal plasma were analyzed by gelatin zymography. We found a clear regional distribution of proteolytic enzymes in the turkey reproductive tract. Each part was characterized by a unique profile of serine proteolytic enzymes of molecular weights ranging from 29 to 88 kDa. The ductus deferens was found to be a site of very intense proteolytic activity. Two metalloproteases of 58 and 66 kDa were detected in all parts of the reproductive tract and seminal plasma. Using electrophoretic methods for detection of anti-trypsin activity, we found three serine proteinase inhibitors in turkey seminal plasma. Two inhibitors were found in the testis and epididymis and a third in the ductus deferens and seminal plasma. Blood plasma was characterized by the presence of two metalloproteinases and one serine proteinase inhibitor (of low migration rate) that were also detected in the reproductive tract. Amidase and anti-trypsin activities (expressed per gram of protein) differed for yellow and white seminal plasma. We concluded that turkey seminal plasma contains metalloproteases, serine proteinases, and serine proteinase inhibitors. The metalloproteases and one proteinase inhibitor are related to blood proteinases but the other two inhibitors and serine proteinases seem to be unique for the reproductive tract.

Limited processing of pro-matrix metalloprotease-2 (gelatinase A) overexpressed by transfection in PC-3 human prostate tumor cells: association with restricted cell surface localization of membrane-type matrix metalloproteinase-1

The expression and activation of matrix metalloproteinases (MMPs) by tumor cells is correlated with progression to invasive and metastatic status. The purpose of this study was to examine the role of increased MMP-2 (gelatinase A) expression in prostate cancer progression utilizing human prostate PC-3 cancer cells that overexpress MMP-2 using gene transfection. PC-3 cells were transfected with pCR-3 vector only and pCR-3 MMP-2 plasmids employing the LipofectAMINE method, and stable transfectants were selected with G418. The expression of MMP-2, tissue inhibitor of metalloproteinase-2 (TIMP-2), and membrane-type MMP 1 (MT1-MMP) in PC-3 parental and transfected cells under serum-free conditions was determined by zymography, immunoblotting, immunofluorescent microscopy, Northern blotting, and/or reverse transcriptase-polymerase chain reaction (RT-PCR). MMP-2 transfected cells produced primarily the proenzyme form of MMP-2; the parental and vector control transfected PC-3 cells did not express any MMP-2 that was detectable by the methods we employed. Treatment of PC-3 MMP-2 transfected cells with Concanavalin A (Con A), in contrast to HT-1080 cells, processed only a small amount of the secreted 72-kd proenzyme to a 62-kd intermediate and a cell-associated 59-kd active form. The low level of secreted pro-MMP-2 processing induced by Con A was inhibited by serine protease inhibitors and was unaffected by cyclic adenosine monophosphate (cAMP). Immunoblotting showed that these cells produced abundant TIMP-2 and lower amounts of MT1-MMP in comparison with Con A-responding HT-1080 cells. HT-1080 cells respond to Con A by translocating MT1-MMP from intracellular localization sites to the plasma membrane, an effect not observed in PC-3 cells. The molecular basis for the low level of processing of pro-MMP-2 by PC-3 cells may be due to an overabundance of TIMP-2 and/or a low level of cell surface active MT1-MMP.

Identification of complexes of gelatinase A and tissue inhibitor of metalloproteinase-2 in human follicular fluid

Background and Aims:  Ovulation involves considerable tissue remodeling in normal ovarian function. These processes are expected to involve matrix metalloproteinases (MMP). Follicular rupture is caused by the degradation of the basement membrane between the thecal and granulose layers, as well as disruption of the extracellular matrix (ECM) at the site of rupture. We report on the existence of the complexes of progelatinase A (proMMP-2), MMP-2 and a tissue inhibitor of metalloproteinase-2 (TIMP-2) using zymographic and immunological techniques in human follicular fluid (HFF). Methods and Results:  Partial purification of the complexes was achieved by using gelatin affinity column chromatography. The peak (tubes 68-73) in this chromatography showed gelatinase activities by gelatin-zymography, and also an inhibition by EDTA (metalloproteinase inhibitor). The molecular weights of the gelatinase activities were approximately 72 and 67 kDa, and were consistent with standard proMMP-2 and MMP-2, as found by using gelatin-zymography. Similarly, the band in this peak was consistent with standard recombinant full-length TIMP-2, as found by the use of western blot analysis, and the molecular weight of the band was approximately 21 kDa. Conclusion:  As proMMP-2, MMP-2 and TIMP-2 exist in the peak from the gelatin affinity column, we expected that these form the complexes. These results indicate that the complexes of proMMP-2/TIMP-2 and MMP-2/TIMP-2 exist in HFF. (Reprod Med Biol 2003; 2: 115-119).

Quantitative differences in matrix metalloproteinase (MMP)-2, but not in MMP-9, tissue inhibitor of metalloproteinase (TIMP)-1 or TIMP-2, in seminal plasma of normozoospermic and azoospermic patients

BACKGROUND

Matrix metalloproteinases (MMPs) and their inhibitors, tissue inhibitors of metalloproteinases (TIMPs), have been detected in reproductive tissues and seminal plasma. The purpose of this study was to quantify MMP-2, MMP-9, TIMP-1 and TIMP-2 in human seminal plasma and to evaluate their association with sperm.

METHODS

Seminal plasma was analysed using ELISA assays for all four analytes in 12 normozoospermic and 12 azoospermic patients and then for MMP-2 only in another 114 men with azoospermia (n = 16), after vasectomy (n = 20) and with sperm counts within the following ranges: 0.3-19 x 10(6)/ml (n = 20), 20-23 x 10(6)/ml (n = 11), 49-57 x 10(6)/ml (n = 12), 96-110 x 10(6)/ml (n = 12), 139-161 x 10(6)/ml (n = 12) and 215-346 x 10(6)/ml (n = 11). Additional zymographic analyses using SDS-PAGE were performed.

RESULTS

All investigated MMPs and TIMPs were detected. MMP-9, TIMP-1 and TIMP-2 were not significantly different in normozoospermia and azoospermia. Only the MMP-2 concentration was significantly decreased in azoospermic compared with normozoospermic patients (mean +/- SD: 650.6 +/- 288.9 versus 1677 +/- 910.4 ng/ml respectively; P = 0.0002) and significantly correlated with the number of sperm (r = 0.54; P < 0.0001).

CONCLUSION

MMP-2 in seminal plasma was strongly correlated to the sperm count in a linear fashion. Its origin and potential function remain to be elucidated.

Expression of matrix metalloproteinase-2 and -9 and their inhibitors, tissue inhibitor of metalloproteinase-1 and -2, in primary cultures of human prostatic stromal and epithelial cells

The production of matrix metalloproteinases (MMPs) by prostatic epithelial and/or neighboring stromal cells is considered to be a property that gives cells the capability to penetrate extracellular matrix barriers in normal or neoplastic growth. In order to examine the role of MMPs in the prostate, we evaluated the expression of MMP-2 and -9 and the tissue inhibitors of matrix metalloproteinases (TIMP)-1 and -2 in primary cultures of prostatic stromal and epithelial cells. These cells were isolated from normal tissues of the different zones of the prostate, from benign prostatic hyperplasia (BPH) and from cancer. Stromal cells, regardless of tissue of origin, secreted the 72-kDa proenzyme form of MMP-2, whereas conditioned media (CM) from epithelial cells demonstrated little/no pro-MMP-2 as examined by zymography. Either type of cell did not secrete MMP-9. RT-PCR evaluation showed stromal cells expressed transcripts for MMP-2, but not for MMP-9. Transcripts for MMP-9 were detected in epithelial cells, although no MMP-9 activity was detected in their CM. Treatment of stromal cells with 1 or 10 ng/ml of transforming growth factor-beta (TGF-beta) moderately increased secretion of pro-MMP-2 protein with little change in MMP-2 RNA. However, treatment of epithelial cells with TGF-beta induced expression and secretion of both MMP-2 and-9. The effect of TGF-beta on expression of MMPs by epithelial cells was not duplicated or affected by treatment with insulin-like growth factor (IGF)-1, epidermal growth factor (EGF), platelet-derived growth factor (PDGF), or basic fibroblast growth factor (bFGF). Stromal cells expressed transcripts of both TIMP-1 and -2. Epithelial cells expressed TIMP-1, but little TIMP-2. TGF-beta did not regulate the expression of TIMP-1 or -2 in either stromal or epithelial cells. Our results suggest that the elevated levels of MMP-2 and -9 observed in prostate development and cancer may be due to the elevated TGF-beta associated with these tissues.

Heparin-Enhanced Zymographic Detection of Matrilysin and Collagenases

Unlike the gelatinases (MMP-2 and -9), matrilysin (MMP-7) and collagenases (MMP-1 and -13) are difficult to detect at low levels in conventional casein or gelatin zymography. In this report, heparin was used to enhance the zymographic assays for MMP-7, -1, and -13. With the addition of heparin to the enzyme sample, MMP-7 can be detected at a level of 30 pg in transferrin zymography and MMP-1 and -13 can be detected at a level of 0.2 ng in gelatin zymography. Carboxymethylated transferrin is used instead of casein as a substrate for assaying rat MMP-7. This substrate does not require a prerun step or substrate cross-linking to give uniform staining and clear band formation. It is necessary for heparin to run to the same region of the gel as the enzyme to produce its enhancing effect. For MMP-7 movement of heparin and enzyme is almost equal; for the collagenases it is necessary to add heparin to each well after the electrophoretic run is underway. Possible mechanisms of activity enhancement are discussed.

Matrix metalloproteinases (MMPs) in fresh human prostate tumour tissue and organ-cultured prostate tissue: levels of collagenolytic and gelatinolytic MMPs are low, variable and different in fresh tissue versus organ-cultured tissue

Prostate tissue was obtained from 22 radical prostatectomies (performed for clinical management of prostate carcinoma) immediately after surgery. A small piece of tissue was fixed immediately in formalin and used for routine histology while a second piece was frozen in OCT and used for immuno-histochemistry. Another small piece was used for isolation of epithelial and stromal cells. The remainder of the tissue was cut into 2 x 2 mm pieces and incubated in organ culture for 8 days. In organ culture, non-malignant, basal epithelial cells underwent a proliferative response. This was accompanied by de-differentiation of glandular structures and by migration of epithelial cells across the surface of the tissue. Erosion of the basement membrane could also be seen in places, but was not widespread. Invasion of epithelial cells into the adjacent stroma was not evident. Production of matrix metalloproteinases (MMPs) with gelatinolytic activity or collagenolytic activity was assessed in organ culture and compared to expression patterns in fresh tissue. MMP-1 (interstitial collagenase) and MMP-9 (92-kDa gelatinase B) were undetectable or low in fresh tissue specimens. Both enzymes were detected in organ culture and both increased over time. Even after 6 days, however, there was only a low level of gelatin-hydrolytic activity and no measurable collagen-hydrolytic activity. In past studies we used organ cultures of normal skin and malignant skin tumours (basal cell carcinomas) to help elucidate the role of collagenolytic and gelatinolytic MMPs in epithelial cell invasion (Varani et al, 2000). Compared to MMP levels observed in skin, levels of these enzymes in prostate are low. The low level of collagenolytic and gelatinolytic MMPs in fresh prostate tissue and in organ-cultured prostate tissue may help explain why there is little tissue destruction in many primary prostate tumours and why the majority of such tumours remain confined to the prostate for extended periods.

Sperm motility inhibitor from human seminal plasma: presence of a precursor molecule in seminal vesicle fluid and its molecular processing after ejaculation

Human seminal plasma contains a protein factor that has the capacity to inhibit the movement of demembranated and intact spermatozoa. This factor 'seminal plasma motility inhibitor' (SPMI) has been shown to originate exclusively from the seminal vesicles. The present results demonstrate that the biological activity of SPMI in semen decreases rapidly from 1000 U/ml, immediately after ejaculation, to 220 U/ml 2 h later. Immunoblots of seminal plasma proteins probed with an antibody against human SPMI, revealed the rapid processing of a predominant 52 kDa SPMI antigen, present in the seminal vesicle secretions. This precursor was degraded initially into intermediate molecular mass fragments of 25-40 kDa, and subsequently into smaller fragments of 17-21 kDa. When seminal vesicle fluid was mixed with prostatic secretions (3:1 v/v), proteases present in prostatic secretions were shown to be responsible for processing of the SPMI precursor. Addition of protease inhibitors such as phenylmethylsulphonyl fluoride (PMSF, 5 mM), benzamidine (100 mM) or ethylenediaminetetraacetic acid (EDTA, 5 mM) to the mixture of seminal vesicle and prostate secretions partially prevented the loss of activity of SPMI by 54%, 27% and 9%, respectively. However, the simultaneous addition of PMSF and benzamidine conferred almost total stability to the SPMI precursor activity. These results demonstrate that SPMI exists as a predominant 52 kDa precursor form in the seminal vesicles and is processed rapidly after ejaculation into less active, lower molecular mass forms by one or more serine proteases and/or metalloproteases of prostatic origin which are present in liquefied semen.

Matrix metalloproteinase 9 expression in primary human prostatic adenocarcinoma and benign prostatic hyperplasia

Matrix metalloproteinase (MMP) expression was investigated in patients with prostatic adenocarcinoma and benign prostatic hyperplasia (BPH). Forty-one men were studied: 26 had histologically proven prostate cancer, with 14 (54%) showing metastatic disease; 15 patients had BPH. Prostatic tissue was obtained from transurethral resection and needle core biopsies; gelatinolytic activity was determined by zymography. Seven gelatinolytic bands were detected, with molecular weights ranging from > 100 kilodalton (kDa) to 29 kDa. Nine of 14 patients (64%) with skeletal metastases had 92 kDa activity, present in only two of 12 patients (17%) with a negative bone scan, and absent in BPH. The 92 kDa gelatinolytic activity was expressed in 73% of aneuploid tumours compared with 20% of diploid tumours. A 97 kDa gelatinase was expressed in 80% of BPH samples and 23% of carcinoma patients. Enzyme bands of 72, 66 and 45 kDa were equally expressed in malignant tissue, irrespective of metastatic status, but were expressed in fewer BPH patients. The 97, 92, 66 and 45 kDa enzymes were identified as being pro-MMP-9 sequences by Western blotting, using a specific antibody directed against the pro sequence of the mature protein. MMP activity appeared to be increased in malignant prostatic tissue compared with BPH. Pro-MMP-9, in its 92 kDa form, was shown to be exclusively expressed by malignant prostatic tissue, and in particular by tumours that exhibited the aggressive and metastatic phenotype.