A nod to the bond between NOD2 and mycobacteria

Mycobacteria are responsible for several human and animal diseases. NOD2 is a pattern recognition receptor that has an important role in mycobacterial recognition. However, the mechanisms by which mutations in NOD2 alter the course of mycobacterial infection remain unclear. Herein, we aimed to review the totality of studies directly addressing the relationship between NOD2 and mycobacteria as a foundation for moving the field forward. NOD2 was linked to mycobacterial infection at 3 levels: (1) genetic, through association with mycobacterial diseases of humans; (2) chemical, through the distinct NOD2 ligand in the mycobacterial cell wall; and (3) immunologic, through heightened NOD2 signaling caused by the unique modification of the NOD2 ligand. The immune response to mycobacteria is shaped by NOD2 signaling, responsible for NF-κB and MAPK activation, and the production of various immune effectors like cytokines and nitric oxide, with some evidence linking this to bacteriologic control. Absence of NOD2 during mycobacterial infection of mice can be detrimental, but the mechanism remains unknown. Conversely, the success of immunization with mycobacteria has been linked to NOD2 signaling and NOD2 has been targeted as an avenue of immunotherapy for diseases even beyond mycobacteria. The mycobacteria-NOD2 interaction remains an important area of study, which may shed light on immune mechanisms in disease.

Mice Dually Disrupted for Nod2 and Mincle Manifest Early Bacteriological Control but Late Susceptibility During Mycobacterium tuberculosis Infection

Pattern recognition receptors Mincle and NOD2 have been implicated in mycobacterial immunity. However, knockout (KO) animal infection studies with Mycobacterium tuberculosis (Mtb) have had mild/delayed phenotypes. Given that genetic susceptibility to infectious diseases can be polygenic, we hypothesized that murine double knockout (DKO) of Mincle and Nod2 would result in exacerbation of altered immunity to mycobacterial infection leading to a more extreme phenotype than either KO alone. To test this hypothesis, we monitored bacterial burden, immune responses and survival following in vivo infections with Mtb in DKO mice for comparison to wildtype (WT) and single KOs. Bacterial burden and immune responses were not significantly affected at 3 and 6 weeks after infection in all mutant mice. At later timepoints, Nod2-KO mice had reduced survival compared to wildtype mice, and Mincle-KO survival was intermediate. Unexpectedly, dual disruption had no further effect; rather, DKO mice phenocopied Nod2-KO mice. We observed that Mtb-related death, exclusively in mice with disrupted Nod2, was accompanied by greater pulmonary cell death and distinct large necrotic foci. Therefore, determining how these receptors contribute to mycobacterial resistance will require analysis of immunophenotypes and their consequences on host pathology.

Underwhelming or Misunderstood? Genetic Variability of Pattern Recognition Receptors in Immune Responses and Resistance to Mycobacterium tuberculosis

Human genetic control is thought to affect a considerable part of the outcome of infection with Mycobacterium tuberculosis (Mtb). Most of us deal with the pathogen by containment (associated with clinical "latency") or sterilization, but tragically millions each year do not. After decades of studies on host genetic susceptibility to Mtb infection, genetic variation has been discovered to play a role in tuberculous immunoreactivity and tuberculosis (TB) disease. Genes encoding pattern recognition receptors (PRRs) enable a consistent, molecularly direct interaction between humans and Mtb which suggests the potential for co-evolution. In this review, we explore the roles ascribed to PRRs during Mtb infection and ask whether such a longstanding and intimate interface between our immune system and this pathogen plays a critical role in determining the outcome of Mtb infection. The scientific evidence to date suggests that PRR variation is clearly implicated in altered immunity to Mtb but has a more subtle role in limiting the pathogen and pathogenesis. In contrast to 'effectors' like IFN-γ, IL-12, Nitric Oxide and TNF that are critical for Mtb control, 'sensors' like PRRs are less critical for the outcome of Mtb infection. This is potentially due to redundancy of the numerous PRRs in the innate arsenal, such that Mtb rarely goes unnoticed. Genetic association studies investigating PRRs during Mtb infection should therefore be designed to investigate endophenotypes of infection - such as immunological or clinical variation - rather than just TB disease, if we hope to understand the molecular interface between innate immunity and Mtb.

Synthetic mycobacterial molecular patterns partially complete Freund's adjuvant

Complete Freund's adjuvant (CFA) has historically been one of the most useful tools of immunologists. Essentially comprised of dead mycobacteria and mineral oil, we asked ourselves what is special about the mycobacterial part of this adjuvant, and could it be recapitulated synthetically? Here, we demonstrate the essentiality of N-glycolylated peptidoglycan plus trehalose dimycolate (both unique in mycobacteria) for the complete adjuvant effect using knockouts and chemical complementation. A combination of synthetic N-glycolyl muramyl dipeptide and minimal trehalose dimycolate motif GlcC14C18 was able to upregulate dendritic cell effectors, plus induce experimental autoimmunity qualitatively similar but quantitatively milder compared to CFA. This research outlines how to substitute CFA with a consistent, molecularly-defined adjuvant which may inform the design of immunotherapeutic agents and vaccines benefitting from cell-mediated immunity. We also anticipate using synthetic microbe-associated molecular patterns (MAMPs) to study mycobacterial immunity and immunopathogenesis.

The major androgen-dependent protease in dog prostate belongs to the kallikrein family: confirmation by partial amino acid sequencing

Canine prostate fluids and seminal plasma contain a major androgen-dependent protein which was identified as a proteolytic enzyme exhibiting an Arg-esterase activity. This protease, as characterized, is shown to be present as a two-chain structure held together by at least one disulfide bridge and composed of approximately 220 amino acids. Amino acid sequence determination of both chains has revealed a clear homology to other known amino acid sequences of serine proteases. Furthermore, the comparison of the presented 58 amino acids of the Arg-esterase with the other sequences revealed a very strong homology (larger than 50%) to members of the kallikrein family. The two chain structure could thus result from autolysis of a single chain enzyme in the 'kallikrein autolysis loop'. Amino acid composition of the canine prostatic enzyme suggests that it is related, but not identical, to pancreatic canine kallikrein.

Epitope analysis of a prostate-specific antigen (PSA) C-terminal-specific monoclonal antibody and new aspects for the discrepancy between equimolar and skewed PSA assays

BACKGROUND

Immunoassays to measure prostate-specific antigen (PSA) often give different values for the same patient samples, and the calibrators among commercial immunoassays are not interchangeable. We developed three novel assays to quantify the free and complexed forms of PSA in serum.

METHODS

We synthesized 46 peptides, which encompassed the entire PSA molecule, and determined the interactions between selected monoclonal antibodies (MAbs) and those peptides or the intact PSA molecule.

RESULTS

MAb PA313 did not cross-react with human glandular kallikrein (hK2), which has 78% amino acid homology to PSA. This MAb bound with KD = 40 nmol/L to the C-terminal peptide of PSA and distinguished between a synthetic peptide derived from PSA (PSA46A: NH2-C-R226KWIKDTIVANP237-COOH) that differed from one derived from hK2 (PSA46B: NH2-C-R226KWIKDTAANP237-COOH) by a single amino acid. Only the MAb combination of PA313/PA121 showed equimolar reactivity with PSA and with PSA complexed with alpha1-antichymotrypsin (PSA-ACT). The free form of PSA (F-PSA) was determined by MAbs PA313/FPA503, and the amount of complexed PSA (C-PSA) in PSA-ACT was determined by alphaACT/PA313. The total PSA (T-PSA) measured by either of the equimolar assays (PA313/PA121 or Tandem-R) was consistent with the sum of F-PSA and C-PSA. In contrast, T-PSA by a skewed assay (IMx) was higher than F-PSA + C-PSA when the ratio of F-PSA to T-PSA (F/T) was >0.15. T-PSA measured by IMx was nearly equal to F-PSA/0.55 + C-PSA. The coefficient 0.55 reflected different reactivities of the IMx assay with PSA-ACT and PSA.

CONCLUSION

The discrepancy between the values measured by equimolar and skewed assays depends on the ratio of free to total PSA in the sample.

High concentrations of the macrophage migration inhibitory factor in human seminal plasma and prostatic tissues

During purification procedures to isolate kallikrein hK2 from human seminal plasma, kallikrein hK2 was found to be associated with another protein after several chromatographic steps. This study was conducted to identify the hK2 companion protein and characterize its properties and distribution. The protein was identified as macrophage migration inhibitory factor (MIF) by its NH2-terminal amino acid sequence. It had an enzymatic activity identical to that of recombinant MIF. Its concentration varied between 1 and 10 micrograms/mL in various seminal plasma. By immunohistochemical analysis, MIF was found to be localized mainly in the epithelial cells of normal and cancerous prostates. Since MIF is a well-known proinflammatory mediator, these results suggest that it may have important functions in both human reproduction and prostatic physiology.

Simple purification procedure for human prostatic kallikrein hK2 in its active form

Kallikrein hK2 is a new potential marker of prostate cancer. It is the last member of the human kallikrein gene family to be isolated. We propose a simple purification procedure permitting us to obtain the active form of hK2 starting from human seminal plasma and using commonly available chromatography matrices. In contrast to recently published papers, this procedure is carried out without any immunoaffinity chromatography step and without the need for any antibody to follow the purification. Furthermore, it does not require any recombinant DNA technology nor sophisticated instruments.

Assessment of the trypsin-like human prostatic kallikrein, also known as hK2, in the seminal plasma of infertile men: respective contributions of an ELISA procedure and of Western blotting

Human seminal plasma (SP) is a unique source of kallikreins. Prostate-specific antigen (hK3), which is a chymotrypsin-like human prostatic kallikrein (CHPK), and its cousin protein (hK2), which is recognized as a trypsin-like human prostatic kallikrein (THPK), have been assessed in infertility disorders to test the hypothesis that oligoasthenoteratozoospermia (OAT) is associated with an abnormal prostatic function. Monoclonal antibodies specific for THPK (hK2) were produced by Immunova, Canada, and used to develop a new enzyme-linked immunosorbent assay procedure and to perform Western blot analyses in SP. The immunoradiometric assay from Hybritech Inc., San Diego, Calif., was selected for CHPK (hK3) measurements in SP. Determinations of the THPK and of CHPK contents in SP from four groups of subjects were performed after validation of the assays. The concentration of both kallikreins was similar in three groups of infertile men, and no statistical difference from the control group was recorded. Western blot analysis confirmed the existence of different molecular forms of both kallikreins in SP. Generally, these molecular forms were not affected by infertility disorders except when obstructive azoospermia led to the exclusion of seminal vesicles, which are the sources of protein C inhibitor (PCI). No THPK-PCI complex was observed because THPK, unlike CHPK, is bound mainly to PCI within a few minutes after ejaculation. These data suggest that measurements of kallikreins in the SP of infertile men are much less useful than evaluation of their different molecular forms. Specifically, the absence of THPK-PCI appears to be a reliable feature of obstructive azoospermia, and this test should be routinely practiced in andrology laboratories.

Contamination of purified prostate-specific antigen preparations by kallikrein hK2

This paper ascertained the contamination by hK2 of two types of PSA preparation, that of Sensabaugh and Blake (J. Urol., 144: 1523, 1990) and that of Deperthes et al (J. Androl., 17: 659, 1996). In the first procedure, the free forms of hK2 co-migrated with PSA during the CM-Sephadex and the Sephacryl S-200 steps. By contrast, in the second procedure a very high proportion of hK2 was separated from PSA. In two different Sensabaugh and Blake procedures, the hK2 contamination per microg. of PSA was found to be respectively 0.3 and 1.0 ng. We conclude that hK2 is a quantitatively minor contaminant of some PSA preparations. That contamination is probably of little consequence for PSA standardization but it could lead to erroneous conclusions in enzymatic studies of PSA.

Abundant cysteine-rich protein-1 is localized in the stromal compartment of the human prostate

The cysteine-rich protein-1 (CRP1) is one of the major proteins of the human prostate. Because of the suspected importance of that protein in cell proliferation and differentiation, its expression was investigated in the prostate, prostatic cancer cells, and other organs of the body. At the mRNA level, the highest concentrations of CRP1 were found in the prostate and the colon followed by the brain and the testis. It was virtually absent from the spleen, liver, heart, and kidney. Prostatic cancer cells PC-3, DU-145, and LNCaP also expressed CRP1 mRNA but virtually no protein. CRP1 protein localization in tissues was determined by immunohistochemical analysis using polyclonal antibodies developed against recombinant CRP1 protein. Strong positive cytoplasmic immunoreactions were observed only in the stromal compartment of the prostate and of other smooth muscle-rich tissues without significant staining in any secretory epithelium. These results, along with previously reported data of colocalization of CRP1 with stress fibers and adhesion plaques, suggest that the main function of CRP1 may be structural.

Serpin-derived peptide substrates for investigating the substrate specificity of human tissue kallikreins hK1 and hK2

The third human tissue kallikrein to be identified, hK2, could be an alternate or complementary marker to kallikrein hK3 (prostate-specific antigen) for prostate diseases. Most of the hK2 in seminal plasma forms an inactive complex with protein C inhibitor (PCI), a serpin secreted by seminal vesicles. As serpin inhibitors behave as suicide substrates that are cleaved early in the interaction with their target enzyme, and kallikreins have different sensitivities to serpin inhibitors, we prepared a series of substrates with intramolecularly quenched fluorescence based on the sequences of the serpin reactive loops. They were used to compare the substrate specificities of hK1 and hK2, which both have trypsin-like specificity, and thus differ from chymotrypsin-like hK3. The serpin-derived peptides behaved as kallikrein substrates whose sensitivities reflected the specificity of the parent inhibitory proteins. Substrates derived from PCI were the most sensitive for both hK1 and hK2 with specificity constants of about 10(7) M-1. s-1. Those derived from antithrombin III and alpha2-antiplasmin were more specific for hK2 while a kallistatin-derived substrate was specifically cleaved by hK1. hK1 and hK2 substrates of greater specificity were obtained using chimeric peptides based on the sequence of serpin reactive loops. The main difference between specificities of hK1 and hK2 arise because hK2 can accommodate positively charged as well as small residues at P2 and requires an arginyl residue at P1. Thus, unlike hK1, hK2 does not cleave kininogen-derived substrates overlapping the region of N-terminal insertion of bradykinin in human kininogens.

Human kallikrein hK2 has low kininogenase activity while prostate-specific antigen (hK3) has none

In the present paper, we determined the kinin-releasing activity of human prostatic kallikrein hK2 and compared it to one of the kallikreins hK1 and prostate specific antigen (hK3). Kinin-like substances active on the rabbit jugular vein were progressively produced when nanomolar concentrations of hK2 were incubated with heated plasma. However in these experiments, hK1 appeared much more potent than hK2 while hK3 was totally inactive. When hK2 was incubated with purified high molecular weight kininogen, several peptides were generated as shown by the analysis on C18 reverse-phase HPLC. Kinin activity was localized exclusively in a small peak having an elution time identical to that of bradykinin while the only important peak obtained with hK1 corresponded to Lys-bradykinin. Finally, the rate of kinin production of hK2 was found to be more than a thousandfold lower than that of hK1. These experiments show that kallikreins hK2 has only a low kininogenase activity. However, it is not excluded that some of the peptides produced by hK2 action could have other types of biological activity.

Purification of enzymatically active kallikrein hK2 from human seminal plasma

Kallikrein hK2 is a member of the human glandular kallikrein family which includes prostate-specific antigen (PSA) and pancreatic-renal kallikrein. The purpose of this work was to isolate and characterize for the first time the enzymatically active form of the hK2 protein starting from the PCI-hK2 complex isolated from human seminal plasma (Deperthes, D., Chapdelaine, P., Tremblay, R.R., Brunet, C., Berton, J., Hébert, J., Lazure, C. and Dubé, J.Y. (1995) Biochim. Biophys. Acta 1245, 311-316). That complex was dissociated by an incubation at alkaline pH and final purification was achieved by C-18 reverse phase HPLC. The purified material contained a 27 kDa band by SDS gel electrophoresis and had the expected NH2-terminal amino acid sequence of hK2. It hydrolyzed synthetic chromogenic substrates containing esters of lysine and arginine but not of phenylalanine. Furthermore, hK2 formed molecular complexes with alpha 2 -antiplasmin, alpha 1-antichymotrypsin, antithrombin III and alpha 2-macroglobulin but not with alpha 1-antitrypsin. In conlusion, the new findings of the present paper are that the PCI-hK2 complex can be dissociated by mild procedures, that the free hK2 protein can be purified thereafter by standard HPLC procedures, that the recovered free hK2 is a trypsin-like enzyme and that it can form molecular complexes with many of the major serum proteinase inhibitors.

Immunohistochemical study suggesting a complementary role of kallikreins hK2 and hK3 (prostate-specific antigen) in the functional analysis of human prostate tumors

The development of monoclonal antibodies directed against prostatic kallikrein hK2 prompted us to evaluate its content, along with that of hK3 (prostate-specific antigen), in human prostate carcinoma. Seventy tumors categorized according to the M.D. Anderson Hospital classification (grade I to IV) were analyzed by immunohistochemistry. The staining intensity or the kallikrein content of benign prostatic hyperplasia glandular tissue (used as control) and of grade I tumors appeared similar. In grade II to IV tumors, histochemical data revealed highly variable hK2 or hK3 content in approximately 25% of tumors. Such patterns are consistent with a current observation related to heterogeneity of prostate tumors. In addition, a few tumors did not express hK3 (n = 3), hK2 (n = 3), or both (n = 3), indicating that some growth patterns of prostatic neoplasia are associated with a lack of secretion or storage of hK3 or hK2 for immunodetection. This statement also appears relevant to metastases. It was interesting to note that 4% of hK3-negative tumors had detectable hK2. Because of the importance of hK3 as a serum marker of prostate disorder, this study addresses for the first time the question of the relative importance of both hK3 and hK2 in the immunohistochemical diagnosis of prostatic tumors. We conclude that hK2 may add new information to prostate cancer diagnosis and characterization.

Potential involvement of kallikrein hK2 in the hydrolysis of the human seminal vesicle proteins after ejaculation

We have recently demonstrated in liquefied human seminal plasma the presence of the novel kallikrein hK2 in association with protein C inhibitor (PCI) as a 75-kDa complex. In the present study, we showed that hK2, immediately after ejaculation, was recovered only in its free form but complex formation with PCI occurred rapidly thereafter and was completed within 10 minutes. That reaction required an enzymatically active kallikrein. In order to determine the patterns of hydrolysis of major seminal vesicle proteins, semenogelins and fibronectin were exposed to hK2 and to hK3 (prostate-specific antigen or PSA) and cleavage sequences were identified by N-terminal sequencing. Free hK2 was able to hydrolyze semenogelins and fibronectin in vitro. Most of cleavage sites were at the carboxyl-side of arginyl residues. Semenogelins were hydrolyzed to a similar extent by catalytic (and similar) concentration of either hK2 or PSA though no common cleavage sites was identified for both proteinases. Unlike semenogelins, fibronectin was hydrolyzed much more efficiently by hK2 than by PSA. These results show that hK2 is enzymatically active during a short period of time after ejaculation, that major seminal vesicle proteins can be the target of this proteolytic activity, and that hK2 and PSA have different substrate specificities.

Kallikreins expression in a mature cystic ovarian teratoma

We report an example of benign cystic ovarian teratoma that was incidentally discovered in a nulliparous 24-year-old woman taking contraceptive pills. Histological examination of the cyst revealed the presence of prostatelike tissue in association with a wide variety of other tissues. The use of highly specific monoclonal antibodies developed against the two prostate-specific kallikreins (hK2 and hK3) in humans allowed the demonstration that the multiple islets of epithelial cells were prostatic tissue in nature and that only part of these cells had conserved their intrinsic property of producing kallikreins.

Isolation of prostatic kallikrein hK2, also known as hGK-1, in human seminal plasma

To demonstrate the presence of kallikrein hK2 in the human prostate and seminal plasma, we used mouse monoclonal antibodies (MAb) against a recombinant hK2-fusion protein. Using one of these MAb 9D5, we detected the presence of several major immunoreactive spots of 22 kDa and minor ones of 31 and 55 kDa in prostate cytosol and seminal plasma. After ion exchange and immunoaffinity chromatography of seminal plasma proteins, the 22-kDa immunoreactive proteins were isolated along with 55- and 75-kDa proteins. The NH2-terminal amino acid sequencing permitted identification of fragments of hK2 and protein C inhibitor, respectively, in the 22- ad 55-kDa bands. Furthermore, immunoblotting experiments in one and two-D gels with two different anti-hK2 MAbs and one polyclonal anti-PCI antibody suggested that the major 55- and 75-kDa bands were covalent hK2-PCI complexes containing either the full-length hK2 chain or only its carboxyterminal fragment in the presence of mercaptoethanol. These results demonstrate for the first time the existence of kallikrein hK2 and suggest that PCI may regulate its activity in seminal plasma.

Search for androgen response elements in the proximal promoter of the canine prostate arginine esterase gene

We have demonstrated the binding of the recombinant DNA binding domain of the rat androgen receptor to a DNA sequence of the canine prostate arginine esterase gene and have determined the functional significance of this sequence in transient transfection experiments. One of the binding sites was localized to a region (-172 to -148 bp) containing the sequence AGGACAACAGGTGTT that has 73% homology with the prostate-specific antigen (PSA) androgen response element (ARE) found at a similar position in the PSA promoter. Competition experiments showed that the androgen receptor had an approximately 100-fold more affinity for the PSA ARE than for the arginine sequence at -172 to -148. Transient cotransfection of 5'-deletion mutants of the arginine esterase promoter and 5'-flanking sequences driving the activity of the reporter gene along with the rat androgen receptor expression vector yielded only negligible inductions of chloramphenicol acetyl transferase (CAT) activity when dihydrotestosterone (DHT) was added to the culture medium. The introduction of one to four repeats of the -172 to -148 sequence of the arginine esterase gene upstream of the basal promoter of the mouse p12 gene in p12.108 also resulted in a minimal induction of CAT activity compared with a 10-fold induction of PSA AREs under similar conditions. These results suggest that the regulation of the canine arginine esterase gene by androgens is most probably achieved by mechanisms that differ from the ones prevailing with the human PSA and kallikrein-2 (hKLK2) genes.

Identification of glandular kallikrein in dog pancreas and determination of its tissue distribution

In order to establish a formal link between previously purified canine urinary kallikrein and dog pancreatic kallikrein whose cDNA sequence has recently been published, we have isolated the pancreatic kallikrein from that animal species. Pancreatic cytosol proteins were sequentially subjected to chromatography on DEAE-Sepharose CL-6B and Concanavalin A-Sepharose, to an autolysis step and finally to two-dimensional gel electrophoresis. Kallikrein immunoreactive spots were identified with an antibody directed against canine urinary kallikrein. These proteins were isolated after electroblotting and the amino acid sequence of their NH2-terminal portion was determined by microsequencing. The sequence was found to be identical to the one deduced from pancreatic kallikrein cDNA. Using the same antibody and immunohistochemical procedures, kallikrein was found to be present in the pancreas, the salivary glands, the kidney, the colon, the lungs and the testis. These results thus confirm the molecular nature of a glandular kallikrein in the canine species.

Characterization of canine pancreas kallikrein cDNA

Using a combination of primer extension and RT-PCR, the cDNA encoding a canine tissue kallikrein expressed in the pancreas was cloned and sequenced. The cloned 0.85 kbp cDNA contained a complete open reading frame encoding a polypeptide of 261 amino acids. The calculated molecular mass of the processed, unglycosylated, 237 amino acid protein was 26,428 Da. Its mRNA was expressed at high levels in the pancreas, kidney and submaxillary gland. The sequence of the encoded protein was highly homologous with canine prostatic arginine esterase (66%) and human renal/pancreatic kallikrein (74%). Therefore, the cloned cDNA encoded a previously uncharacterized canine kallikrein enzyme which was named dog renal/pancreatic kallikrein or dK2 according to the new nomenclature for kallikrein gene family members. Because of its specific pattern of tissue expression and the presence of all the amino acid residues necessary for kininogenase activity, we suggest that dK2 is the canine true tissue kallikrein.

Characterization of rhesus monkey prostate specific antigen cDNA

Using a RT-PCR approach, we obtained two overlapping cDNA clones containing the entire 1.5 kb sequence of rhesus monkey prostate specific antigen (rmPSA). The sequence obtained revealed an open reading frame of 261 amino acids. One potential N-glycosylation site was identified at Asn-78. The calculated molecular mass for the unglycosylated mature protein was 26,147 Da. Extensive amino acid homology (89%) was observed between rmPSA and its human counterpart. These results demonstrate that rhesus monkey and man prostate share a major biochemical component, and suggest that this animal species might be useful to answer specific questions related to human prostatic function and pathology.

Transcriptional regulation of dog prostate arginine esterase gene by androgens

These studies were designed to define the molecular events involved in the modulation of dog prostate arginine esterase gene expression following short castration intervals and androgen treatment. Arginine esterase enzymatic activity and protein levels decreased about 50% 24 h after castration. Thereafter, a more progressive decrease was observed, resulting in 2-4-fold lower levels in 12-day castrates than in the intact controls. Total prostatic arginine esterase mRNA levels slowly decreased during the first five days after castration but more abruptly thereafter and were about 150-fold lower in 12-day castrated animals. By contrast, in isolated prostatic nuclei, levels of arginine esterase RNA precursors and mature transcripts rapidly fell following orchiectomy, with a 50-70% decrease 24 h after castration. Nuclear run-on experiments confirmed that the latter effects were the result of decreased arginine esterase gene transcription. All these changes could be at least partially reversed by administration of testosterone cypionate. Furthermore, no striking modifications in the proportion of epithelial/stromal cells in the prostatic tissue were observed following orchiectomy. These results show that castration and androgens exert very rapid effects on the gene expression of arginine esterase, and that the regulation occurs at the transcriptional level.

Demonstration of DNA binding factors interacting with a fragment of the canine prostate arginine esterase gene promoter

We have studied, by the gel mobility shift assay, the interaction of DNA binding proteins with a fragment of the proximal promoter (from nucleotides -177 to -47) of the androgen-regulated canine prostate arginine esterase gene. Several shifted bands were obtained using nuclear extracts from various tissues. In the case of the prostate, the intensity of some of the shifted bands was decreased or increased when the extracts were prepared from animals that had been castrated 12 days earlier. Several of the DNA-protein complexes could be assigned to an interaction with part or all of the sequence GGGGGTGGGGG from-124 to -114. We also obtained evidence for the presence of protein(s) interacting with an Sp1 motif present in the same fragment. These results suggest that some ubiquitous factors different from the androgen receptors could be involved in the regulation of the arginine esterase gene.

Elevated in vitro translation of a 25-kDa protein in renal cell carcinoma

As a first step in understanding the changes in protein synthesis that occur in renal cell carcinoma, we have prepared poly(A)+ RNA from surgically removed tumors and from their normal tissue counterpart. These RNAs were then translated in vitro in the rabbit reticulocyte lysate system and the synthesized labeled polypeptides were separated by one- and two-dimensional gel electrophoresis. A major 25-kDa primary translation product was observed with all renal cell carcinomas. The synthesis of this protein was barely detectable with the RNA from normal tissue adjacent to the tumor. To determine if this protein could be further processed (removal of signal peptide and (or) core glycosylation), canine pancreatic microsomal membranes were added to the system. This addition resulted in the formation of a vertical row of three additional spots, with the same isoelectric point as the primary translation product and with molecular masses ranging from 27 to 31 kDa. The 31-kDa protein was retained on Concanavalin A. After digestion with endoglycosidase H, it was no longer visible on sodium dodecyl sulfate gels and a new 27-kDa band was generated suggesting that the mature protein was indeed a glycoprotein. Future experiments will be aimed at identifying this protein and examining its potential value as a marker of renal cell carcinoma.

Variations in 3H-diisopropylfluorophosphate binding proteins in human seminal plasma

We have characterized the electrophoretic pattern and variations in 3H-diisopropylfluorophosphate (DFP)-binding proteins in human seminal plasma from normal men and from 103 patients attending the infertility clinic of our hospital. This study shows that 34 kDa prostate-specific antigen (PSA) is the major 3H-DFP-binding protein and that two other ubiquitous bands of 100 and 60 kDa are also present in seminal plasma from all the men studied. Additional bands of 92, 50-54 (doublet) and 38 kDa were also observed in some patients. The 38 kDa band was shown to be a highly glycosylated form of PSA. Further complexity was demonstrated by two-dimensional gel electrophoresis in the 27-30 kDa range of the gels since at least 10 major spots and rows of spots were seen. The concentration of these spots, including PSA, was extremely variable, as was their pattern of inhibition by various active site inhibitors of serine-proteases; these variations were not correlated with any specific sperm characteristics. With the exception of PSA, the proteins have not been identified. Their distribution suggests that most of them are exclusively of prostatic origin although a few could also derive from the seminal vesicles or blood. Future studies will be aimed at determining the nature of these proteins and their potential usefulness in andrology.

Characterization and expression of the prostatic arginine esterase gene, a canine glandular kallikrein

The prostatic arginine esterase gene was isolated from a genomic library prepared with dog liver DNA in lambda EMBL3. The selected clone contained an insert of approximately 17 kb which included the whole coding portion of arginine esterase mRNA (5 exons plus 4 introns), 2 kb upstream from the initiation site and 12 kb downstream from the polyadenylation site. The intron-exon boundaries were identical to all known mammalian kallikrein genes. The deduced amino acid sequence indicated a high degree of identity (51-61%) with other kallikreins expressed not only in the prostate but also in the pancreas of various animal species. The 5'-flanking sequences contained potential regulatory elements such as a variant TATA box (TTTAAA), a CCAAT box, a SP1 transcriptional factor binding site (GGGCGG), and two TGTCCT motifs resembling glucocorticoid response elements. Southern blot analysis with an amplified cDNA fragment of 487 bp corresponding to the 5' portion of the mRNA and with a DNA probe from a different portion of the arginine esterase gene indicated the presence of two to three homologous genes in the canine genome while in a previous study a single band was detected using a 400-bp arginine esterase cDNA corresponding to the 3' portion of the mRNA. These results suggest that the arginine esterase gene belongs to a small kallikrein gene family. Arginine esterase mRNA is expressed primarily in the prostate but also at an extremely low level (approximately a thousandfold less) in several other tissues including the liver, the gracilis thigh muscle, the kidney, and the pancreas.

Northern analysis of gene-specific primary transcripts using synthetic oligonucleotide probes labeled at high specific activity

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Expression of Zn-alpha 2-glycoprotein and PSP-94 in prostatic adenocarcinoma. An immunohistochemical study of 88 cases

Zn-Alpha 2-Glycoprotein (Zn-Alpha 2-GP) and prostatic secretory protein of 94 amino-acids (PSP-94) were recently isolated from the human prostate. Their expression in benign and malignant well-differentiated and poorly differentiated components of 88 prostates with prostatic adenocarcinomas, and in 25 metastases, was evaluated using polyclonal antibodies developed against these antigens. Zn-Alpha 2-GP was present in benign hyperplastic glands in 91.1% of cases, but in only 40.7% (poorly differentiated component) to 48.5% (well-differentiated component) of prostatic adenocarcinomas, and in 8% of metastases. The expression of PSP-94 was present in 89.3% of benign hyperplastic glands, but in only 50% (well-differentiated adenocarcinoma component) to 57.3% (poorly differentiated component) of prostatic adenocarcinomas and 28% of metastases. The expression of these proteins by the tumor was unrelated to the initial stage and the tumor grade. Because of their low frequency in prostatic adenocarcinomas, especially in metastases, Zn-Alpha 2-GP and PSP-94 appear to have a limited diagnostic usefulness. Further studies are needed, however, to explore other clinical applications of these two new prostatic secretory proteins.

The concentration of immunoreactive prostate specific antigen is not decreased in viscous semen samples

The concentration of immunoreactive prostate specific antigen (PSA) was determined in the seminal plasma of 79 men who were classified into 4 groups according to sperm characteristics: there were 3 groups with low viscosity sperm (normal, large or small volume) and one group with high viscosity and normal volume. PSA concentrations in the group with high viscosity were not significantly different from the group with low viscosity and normal or large volume. PSA was significantly increased only in the "small volume group" (p less than 0.01). These results show that absolute amounts of PSA are not decreased in seminal plasma with high viscosity and therefore are not the cause of abnormal liquefaction of the semen in these patients.

Zinc binding to major human seminal coagulum proteins

In vitro binding of zinc to proteins of the human ejaculate and of the various male accessory gland secretions was evaluated. The proteins were separated by sodium dodecyl sulfate gel electrophoresis and transferred to nitrocellulose filters that were subsequently incubated with 65ZnCl2. High levels of zinc binding were observed to approximately 20 protein bands (14 to 70 kDa) of the coagulated seminal plasma. There was only low binding to proteins of the spermatozoa and virtually no binding to any protein of the epididymal and prostatic fluids. When sperm liquefaction was allowed to occur, 65ZnCl2 binding to high-molecular weight proteins decreased rapidly, and after 15 min only the binding to proteins of molecular weights less than 25 kDa remained. In addition, zinc concentration was determined both in the centrifugate and in the supernatant after centrifugation of the coagulum. Zinc concentrations in the centrifugate and the supernatant were, respectively, 147 +/- 72 micrograms/g and 31 +/- 22 micrograms/g. The whole supernatant contained only 12% +/- 4% of total sperm zinc. Finally, in highly viscous sperm samples the concentration of zinc was not significantly different from that in normally liquefying sperm (167 +/- 87 micrograms/ml compared to 188 +/- 107 micrograms/ml). The main extracellular targets of prostatic zinc in humans are the secreted seminal vesicle proteins. The role of this binding remains unknown, however, because no direct relationship could be established between the concentrations of this metal and the phenomena of coagulation and liquefaction.

Synthesis of alpha 1-acid glycoprotein by the human prostate

In order better to define the extent of protein synthesis capacity of the human prostate, we have studied the translation of selected serum proteins using isolated poly(A)+ RNA preparations and the rabbit reticulocyte lysate system. The translation of alpha 1-acid glycoprotein could be conclusively demonstrated but there was no apparent translation of albumin and plasmatic transferrin. Labeled alpha 1-acid glycoprotein was identified by specific immunoprecipitation with a commercial anti alpha 1-acid glycoprotein antiserum and correct processing by canine pancreatic microsomal membranes. Furthermore, we have shown by the immunoperoxidase technique that alpha 1-acid glycoprotein was indeed localized mainly in prostatic epithelial cells in 2 out of 2 patients with benign prostatic hypertrophy and in 3 out of 11 patients with prostatic adenocarcinoma. The significance of the synthesis and secretion of alpha 1-acid glycoprotein by prostatic cell themselves is presently unknown. However, we think that it could represent an interesting subject to explore further in relation with prostatic inflammation.

Looking for human glandular kallikrein-1 in the prostate

Based on recent studies indicating that human glandular kallikrein-1 (hGK-1) mRNA was present in the prostate, we have undertaken to determine whether the prostate contained trypsin-like proteases with properties compatible with those deduced from hGK-1 gene nucleotide sequence. The first series of experiments showed that only minimal levels of trypsin-like enzymatic activity, determined with synthetic substrates, were present in chromatographic fractions of prostatic glycoproteins having a molecular weight in the range expected for hGK-1, i.e., 25,000-35,000. Because of this, we used [3H]diisopropylfluorophosphate (DFP) labeling alone or in the presence of various serine-protease inhibitors to identify trypsin-like proteases in the prostate. Two-dimensional gel electrophoresis of prostatic glycoproteins showed the presence of minor spots of 18-32 kDa. These spots were slightly more acidic than were those of prostate specific antigen (PSA) and were completely inhibited by preincubation with tosyl lysine chloromethyl ketone and p-nitrophenyl-p-guanidobenzoate in contrast to PSA spots that were not affected by these treatments. When a similar procedure was applied to total cytosolic proteins instead of glycoproteins, an additional 30 kDa DFP binding protein was observed. This relatively abundant protein was much more acidic than was PSA and was not inhibited by any of the protease inhibitors tested. In conclusion, this study has permitted us to demonstrate the presence of two sets of proteins that have physicochemical properties compatible with those that can be deduced from the information contained in the hGK-1 gene.

High level of expression in the prostate of a human glandular kallikrein mRNA related to prostate-specific antigen

Using a synthetic oligonucleotide primer complementary to human prostate-specific antigen mRNA, we found that an additional sequence possibly similar to human glandular kallikrein-1 could be read by a primer-extension sequencing technique. We were able to confirm the identity of that additional sequence with another oligonucleotide primer complementary to a specific region of the human glandular kallikrein-1 mRNA sequence. Northern blot analysis with 2 oligonucleotide probes respectively specific for prostate-specific antigen and human glandular kallikrein-1 mRNAs showed that the length of both mRNAs was similar at 1.5 kb. The level of human glandular kallikrein-1 mRNA relative to that of prostate-specific antigen could be estimated as approx. 10-20%. This study constitutes the first evidence that the human glandular kallikrein-1 gene is expressed at a high level in a human tissue.

Nucleotide sequence of the androgen-dependent arginine esterase mRNA of canine prostate

The nucleotide sequence of canine prostate arginine esterase mRNA was determined using a 400 bp cDNA clone and primer-extended cDNA transcripts for the 5'-coding and noncoding regions. The mRNA contains 864 nucleotides encoding a protein of 236 amino acids preceded by 24 amino acids which constitutes both the signal and the zymogen peptides. The sequence indicates the presence of one potential glycosylation site. A high degree of homology was found between the canine enzyme and other members of the kallikrein family including human prostate specific antigen. The protein appears to be specified by a single gene.

Androgen regulation of canine prostatic arginine esterase mRNA using cloned cDNA

Canine prostatic arginine esterase complementary DNA has been cloned in pPBS27, a new cloning vector. The relative abundance of androgen-regulated mRNA in intact dog prostate was reflected by the finding that a high proportion of the clones in the cDNA library hybridized strongly by plaque or colony hybridization with a poly(A)+ RNA probe from intact dog prostate but not with a poly(A)+ RNA probe from castrated dog prostate. One clone carrying a 400 base pairs cDNA insert was selected for further studies. Translation of the hybrid-selected RNA in a cell-free system resulted in the production of a 31 kDa peptide immunoprecipitable by antibodies against arginine esterase. This identification was confirmed by partial sequence analysis of the cDNA revealing an encoding protein with high homology to known kallikreins. Northern blot analysis of poly(A)+ and total RNA showed that arginine esterase mRNA had an approximate size of 1.0 kb which corresponded to a major androgen-regulated RNA species that could be observed after denaturing agarose gel electrophoresis of prostatic poly(A)+ RNA from intact dogs. Dot-blot analysis showed that dogs which had been castrated 3 weeks before had more than 100-fold lower arginine esterase mRNA level than intact dogs or castrated dogs treated with Depo-testosterone.

In vitro translation of human prostatic acid phosphatase mRNA and processing of the translation products by microsomal membranes and endoglycosidase H

Poly(A)+ RNA was isolated from human prostatic tissue and translated in vitro in a rabbit reticulocyte lysate translation assay. Acid phosphatase labeled with [35S]methionine was immunoprecipitated with an antibody against seminal plasma acid phosphatase. Two-dimensional polyacrylamide gel electrophoresis of the immunoprecipitate, followed by fluorography, revealed the presence of two spots (one major and one minor), both having a molecular mass of 43 kilodaltons (kDa) and an isoelectric point higher than mature acid phosphatase. Addition of canine pancreatic membranes to the translation assay resulted in the formation of four immunoprecipitable spots with molecular masses ranging from 43 to 49 kDa on one-dimensional gels. These spots probably represent acid phosphatases containing one to four core sugar groups, since after the addition of endoglycosidase H the molecular mass heterogeneity was abolished and we observed only one major band with a molecular mass (41 kDa) slightly lower than the ones of the primary translation product. These results suggest that human prostatic acid phosphatases are synthesized as two 43-kDa preproteins, which are further processed to 41-kDa proteins by removal of their signal peptide. Heterogeneity of the native protein arises mostly from glycosylation at four sites and not from differences in the amino acid sequence of the various forms.

Immunohistochemical localization of a prostatic secretory protein of 94 amino acids in normal prostatic tissue, in primary prostatic tumors and in their metastases

Using the immunoperoxidase technique, we have studied in normal, hyperplastic and adenocarcinomatous prostates the tissue localization of an abundant 94 amino acid protein secreted by prostatic epithelial cells. In normal and hyperplastic prostates, strong immunoreactivity was found exclusively in glandular epithelial cells. No reaction was observed over the stroma. In well differentiated adenocarcinoma, the acinar cells were generally stained less intensely than in benign prostatic hyperplasia while in poorly differentiated tissue, strongly positive immunoperoxidase staining was found in some cancer cells scattered in the stroma. All prostatic cancer tissues examined (N = 21), with the exception of one, exhibited at least a few positive immunoreactive areas for the 94 amino acid secretory protein. In addition, immunoperoxidase staining was observed in lung and bone marrow metastases respectively in two patients with prostatic carcinoma. All other normal tissues and non-prostatic cancers studied to date were negative. These results suggest that this new marker could be a useful addition to prostatic acid phosphatase and prostate specific antigen.

Isolation from human seminal plasma of an abundant 16-kDa protein originating from the prostate, its identification with a 94-residue peptide originally described as beta-inhibin

In addition to other known markers of the human prostate, it was shown that the prostatic fraction of the split ejaculate was rich in a 16-kDa protein with properties not described previously. This protein was purified from human seminal plasma using ammonium sulfate precipitation, DEAE-Sepharose CL-6B ion exchange chromatography, and gel filtration on Sephadex G-100. The purified protein showed a single prominent spot on two-dimensional gel electrophoresis. The sequence of the first 40 amino acids that could be positively identified was identical to that of a prostatic secretory protein of 94 amino acids (PSP94) previously designated as beta-inhibin. Antibodies produced in rabbits against the purified protein were used to develop a radioimmunoassay. These antibodies appeared to recognize only the NH2-terminal portion of the native molecule since they did not react with a synthetic peptide composed of the 28 C-terminal residues. The radioimmunoassay showed that the concentration of the protein was 1320 +/- 183 micrograms/ml in the seminal plasma of adult fertile men and 1134 +/- 136 micrograms/ml in vasectomized patients. In hypertrophic and adenocarcinomatous prostates, the concentrations were 326 +/- 156 and 104 +/- 23 micrograms/ml, respectively, while values were lower than 0.060 micrograms/ml in the testis, epididymis, vas deferens and liver. The blood plasma concentration was 0.019 +/- microgram/ml in 23 asymptomatic men 45 to 65 years old and 0.115 +/- 0.036 microgram/ml in eight patients with prostate cancer.(ABSTRACT TRUNCATED AT 250 WORDS)

Molecular cloning and sequence of the cDNA for a 94-amino-acid seminal plasma protein secreted by the human prostate

The precursor to a seminal plasma protein reported to have inhibin-like activity was characterized through cDNA cloning and sequencing. It is a 114-amino-acid polypeptide which differs from its seminal plasma derivative mainly by the presence of a 20-residue amino-terminal extension, a putative signal sequence, carrying a possible N-glycosylation site. The protein is specified by a single gene per haploid genome. Its mRNA is detectable in the prostate but not in the testis, which suggests that it is primarily a prostatic secretory protein.

The major 40-kDa glycoprotein in human prostatic fluid is identical to Zn-alpha 2-glycoprotein

A major 40-KDA protein secreted by human prostate was isolated from whole seminal plasma by sequential column chromatography on DEAE-Sepharose CL-6B, concanavalin A(Con A)-Sepharose, and Sephadex G-100. Although the purified preparation still contained minor contaminants, its amino acid composition was found to be identical to the one of a glycoprotein isolated previously from seminal plasma by Lin et al (1983). Antibodies against this protein were produced in rabbits and their use in immunoblotting experiments revealed the presence of the antigen in several tissues including the prostate, the liver, the heart, the kidney, the epididymis, and the testis. A radioimmunoassay confirmed these results and showed that blood serum concentrations of this protein were relatively high in men (81 +/- 3 micrograms/ml), women (68 +/- 3 micrograms/ml), and cord blood of newborns (32 +/- 1 micrograms/ml). The serum concentrations of this protein along with its physicochemical characteristics suggested that it could be identical to Zn-alpha 2-glycoprotein, a human serum protein previously isolated by Burgi and Schmid (1961). This hypothesis was confirmed by a double immunodiffusion analysis using a commercial anti-Zn-alpha 2-glycoprotein antiserum. Finally, in vitro translation of prostatic poly(A) + RNA in rabbit reticulocyte lysate in the presence of canine pancreatic microsomal membranes resulted in the formation of an immunoprecipitable 42-kDa band. These results show that Zn-alpha 2-glycoprotein can be synthesized in the prostate itself. The demonstration of high concentrations of this protein in prostatic tissue and prostatic secretion should facilitate the elucidation of its role in the prostate and in other tissues.

Purification of ram seminal plasma acid alpha-glucosidase

1. Ram seminal plasma alpha-glucosidase has been purified in order to increase our knowledge of this enzyme and of its role in epididymal physiology. 2. Since the enzyme behaved differently from other known acid alpha-glucosidases and was not affinity-adsorbed on dextran gels, another approach had to be used. 3. The final procedure included an ethanol precipitation step, sequential chromatography on hydroxylapatite and DEAE Sepharose CL-6B, isoelectric focusing in polyacrylamide gels and ultrafiltration. 4. The resulting purification factor of alpha-glucosidase was 9822 with an overall yield of 5%. 5. The purified material consisted of several isoforms with a mol. wt of 105,000 and isoelectric points varying between 4 and 5.

Radioimmunoassay in blood plasma of arginine esterase: the major secretory product of dog prostate

We have developed a radioimmunoassay to determine serum levels of arginine esterase, the major secretory product of the canine prostate. Although the antibodies recognized other related proteins in immunoblotting conditions, particularly in the pancreas, the radioimmunoassay appeared specific for arginine esterase of prostatic origin and reacted only slightly or not at all with cytosolic proteins from salivary glands, liver, skeletal muscles, and kidney. In serum samples, the sensitivity limit of the assay was about 2.5 ng per ml. The interassay and intraassay variations for serum samples that contained concentrations of arginine esterase ranging from 6 to 21 ng per ml were, respectively, 14% and 24%. Sera from 30 adult males and 14 adult females contained, respectively, 71 +/- 9 and 5.3 +/- 0.4 ng per ml. In a group of 12 dogs treated daily for 36-39 days with 50 micrograms of D-Trp6-luteinizing hormone-releasing hormone ethylamide, the concentrations of arginine esterase in the serum decreased progressively and became identical with those observed in the females. These results constitute the first evidence for the presence of a serum marker of the normal prostate in an experimental model. It should be particularly useful to test the effects of various agents on the prostate.

The influence of immobilization stress on cardiac protein synthesis. A possible regulatory role for glucocorticoids

High serum corticosterone levels and transient depletion of cytosolic glucocorticoid receptor binding capacity were observed in rat cardiac muscle following immobilization stress. To evaluate the effect of this treatment on the protein synthetic capacity, biologically active polyribosomes were used to direct the in vitro synthesis of polypeptides in the rabbit reticulocyte lysate. The results of these experiments indicate that the template activity of several messenger RNAs coding for major myofibrillar proteins was increased. This change in protein synthetic activity was not observed in adrenalectomized animals. Collectively, these results suggest that glucocorticoids are involved in the regulation of cardiac protein biosynthesis.

Variations of glucocorticoid receptors in intact or denervated muscles: lack of cause-effect relationship with muscle atrophy in the rat

The process of muscular atrophy following denervation has been tentatively ascribed to the influence of glucocorticoids (G) because of the rapid increase of cytosolic G receptors (RG) after sciatic nerve section. It appears however that the level of muscular atrophy is similar: in slow or fast-twitch muscles in spite of huge variations in RG; in intact or adrenalectomized (ADR-X) rats. Moreover, the protein muscle profile of intact of ADR-X rats after gel electrophoresis is similar but drastically decreased after 3 weeks of denervation. We conclude that there is no cause-effect relationship between muscle atrophy and RG elevation after nerve section.