Lutz Konrad

Role of TGF-βs in normal human endometrium and endometriosis

Endometriosis is characterized by presence of endometrial tissue outside the uterus. Prevalence is estimated at 6-10% in the general female population and many patients experience pain and/or infertility. Diagnosis is achieved by laparoscopic intervention followed by histological confirmation of viable endometriotic tissue. Mild cases are managed medically with contraceptive steroids and non-steroidal anti-inflammatory agents. Surgery provides relief to women in pain but symptoms recur in 75% of cases within 2 years. Starting with menstruation, we have categorized endometriosis into six stages, namely (1) shedding of cells, (2) cell survival, (3) escape from immune surveillance, (4) adhesion to peritoneum, (5) angiogenesis and (6) bleeding. In most of these biological processes, which resemble metastasis, transforming growth factor-beta (TGF-betas) and their high-affinity receptors are involved directly or indirectly. TGF-betas are abundantly and differentially expressed in the endometrium under hormonal control. Although they are preferentially synthesized in the stroma, glands and macrophages also secrete TGF-betas into the uterine fluid, where interaction with preimplantation embryos is suspected. Because mRNA and protein expression of all three TGF-betas is increased around menstruation, we suggest that TGF-betas might be involved in initiation of menstruation. Furthermore, because of high postmenstrual TGF-beta3 levels, we suppose that it might participate in scarless postmenstrual regeneration of endometrium. Our suggestions pave the way to novel routes of investigation into the roles of TGF-betas during menstruation and endometriosis.

Neurogenic origin of human prostate endocrine cells

OBJECTIVES To determine the histogenetic origin of prostate neuroendocrine cells in human embryos. METHODS Prostatic tissue in human fetuses, ranging in gestational age from early week 10 to term, and infantile and pubertal glands were studied immunohistochemically. The distribution of neuroendocrine cells within the developing gland was semiquantitatively determined. Antibodies against the neuroendocrine markers chromogranin A (CgA) and protein gene product 9.5 (PGP), along with markers of prostatic secretion (prostate-specific antigen [PSA], prostatic acid phosphatase [PAP]), were used. They were applied either individually or in double-labeling experiments, as well as in experiments combining CgA immunohistochemical analysis with in situ hybridization or in situ end-labeling. RESULTS In embryos of less than 65-mm crown-rump length (CRL) (ie, younger than 12 weeks of gestation), the epithelium of the urogenital sinus was free of endocrine cells. On either side of the future prostatic mesenchyme, paraganglia containing CgA-immunoreactive cells are present, which start to penetrate the urogenital mesenchyme. In the late 10th week, these CgA-immunoreactive cells are found dispersed in the urogenital mesenchyme. In embryos of 65-mm CRL, when prostatic anlagen start to sprout from the urogenital epithelium, very few (but typically shaped) neuroendocrine cells appear in the urogenital sinus epithelium. Later, after the 12th week, when solid prostatic ducts have started forming, CgA-immunoreactive neuroendocrine cells are also present in these buds. The number of neuroendocrine cells in the urethral epithelium is considerably increased, and with the continuous sprouting and lumen formation of prostatic anlagen, neuroendocrine cells are transported into the future gland. Neuroendocrine cells observed in stroma of prenatal and postnatal prostates may also contribute to the neuroendocrine cell population of the gland. CONCLUSIONS Our results provide the first evidence that human prostate neuroendocrine cells represent a cell lineage of their own, being of neurogenic origin and therefore distinct from the urogenital sinus-derived prostate secretory and basal cells.

VDAC2 (porin-2) expression pattern and localization in the bovine testis.

In this study, sequencing of voltage-dependent anion channel 2 (VDAC2, porin-2) cDNA from bovine testis is reported. High identity to the murine, rabbit, and human subtypes at both the nucleotide and amino acid levels is demonstrated. mRNA analysis revealed expression of VDAC2 in bovine testis, whereas high levels of VDAC2 proteins were found in late spermatocytes, spermatids, and spermatozoa. In contrast, VDAC1 (porin-1) is exclusively localized in Sertoli cells. The possible role of testicular VDAC2 in providing energy metabolites and in germ cell apoptosis is discussed.

Immunohistochemistry of prostasomes from human semen.

To elucidate the origin of so‐called “prostasomes” in human semen, a polyvalent rabbit antiserum was produced against a highly purified preparation of these secretory particles.

FIBRONECTIN IN HUMAN PROSTATIC CELLS IN VIVO AND IN VITRO : EXPRESSION, DISTRIBUTION, AND PATHOLOGICAL SIGNIFICANCE

Abstract In the present study we examined the expression and release of the extracellular matrix glycoprotein fibronectin (FN) in a prostate cancer cell line (LNCaP) and in primary prostatic stromal cells using the reverse transcription–polymerase chain reaction (RT-PCR) and by an enzyme-linked immunosorbent assay. Perturbation experiments in vitro using antibodies directed against FN and the FN receptor were also performed. Immunohistochemistry was used to show the in vivo distribution of FN and the FN receptor in tissue sections of normal human prostate, benign prostatic hyperplasia, and prostate carcinoma. The expression of the oncofetal FN ED-B segment in benign prostatic hyperplasia and prostate carcinoma tissue was investigated by RT-PCR. The FN mRNA was expressed by LNCaP and primary prostatic stromal cells, respectively. Both cell types released FN into the medium in a time-dependent manner, whereby FN secretion was about 2.5-fold higher in cultures of stromal cells relative to LNCaP cells. Blocking FN with anti-FN antibodies resulted in a significant decrease in cell adhesion for LNCaP cells and a change in morphology for the primary stromal cells. FN was located mainly in the stromal compartment of the prostate, showing a distinct distribution pattern in prostate carcinoma, whereas the FN receptor was detectable only in the prostate epithelia. RT-PCR experiments showed the expression of the oncofetal FN ED-B segment in benign prostatic hyperplasia and prostate carcinoma tissue, with a 3.5-fold higher expression in the prostate carcinoma probes. Our data point to an important role for FN in cell adhesion of prostatic cells and show that an alternatively spliced FN mRNA is upregulated in the pathologically altered human prostate.

Prognostic value of combined triple-reverse transcription-PCR analysis for prostate-specific antigen, human kallikrein 2, and prostate-specific membrane antigen mRNA in Peripheral blood and lymph nodes of prostate cancer patients

Purpose: We present the largest study of both peripheral blood and lymph node samples examining the utility of reverse transcription-polymerase chain reaction (RT-PCR) for established molecular markers as a diagnostic tool in the molecular staging of prostate cancer patients undergoing radical prostatectomy. Experimental Design: Peripheral blood from 358 patients was obtained before radical prostatectomy. Corresponding obturatory lymph node samples were collected from 153 of these patients. Nested RT-PCR for prostate-specific antigen (PSA), human kallikrein 2 (hK2), and prostate-specific membrane antigen (PSMA) were performed on cDNA from peripheral blood. The lymph node cDNA was analyzed for PSA und hK2 expression. Results: RT-PCR in peripheral blood was positive in 124 (34.6%) of 358 samples for PSA, 215 (60.1%) of 358 for PSMA, and 97 (27.1%) of 358 for hK2. Comparison of positive RT-PCR rates of pT2 and pT3 tumors in corresponding peripheral blood for PSA, PSMA, and hK2 were 31.9 and 40.0%, 58.8 and 62.5%, and 26.9 and 27.5%, respectively. Histopathologically, cancer-free lymph node samples were positive in RT-PCR for PSA and hK2 in 70 (49.6%) of 141 and 89 (63.2%) of 141 of cases. All histologically positive lymph node samples (n = 12, pN+) were positive for PSA RT-PCR. PSA RT-PCR alone, as well as combined PSA/PSMA RT-PCR evaluation, in peripheral blood showed a significant association with grading. PSA RT-PCR lymph node-negative samples were significantly less likely positive in their corresponding peripheral blood RT-PCR sample. Conclusions Although the preoperative PSA RT-PCR in peripheral blood correlated with the grading of prostate cancer, no combination of RT-PCR results using “triple” markers (PSA, hK2, PSMA) in peripheral blood and/or lymph nodes yielded additional preoperative staging information.

Cell lineage characteristics of human prostatic stromal cells cultured in vitro.

An in vitro model of prostatic stromal cells suitable for experimental studies of the pathogenesis of BPH is still lacking. We therefore standardized the isolation, cultivation, and characterization of human prostatic stromal cell lineages.

Transforming Growth Factor-β2 Mediates Mesenchymal-Epithelial Interactions of Testicular Somatic Cells12

Transforming growth factor-β2 (TGFβ2) is an important mediator of growth and differentiation. We here describe for the first time the complete sequence of the TGFβ2 complementary DNA derived from peritubular myoid cells of the rat testis. The size of the rat TGFβ2 complementary DNA was 1245 bp, and the deduced protein sequence contained 414 amino acids. Sequence comparison with the human and mouse amino acid sequences demonstrated 96.4% and 97.9% sequence identities, respectively. To elucidate the functional role of TGFβ2 in testicular somatic cells, we studied its secretion in vitro in monocultures and cocultures of mesenchymal peritubular and epithelial Sertoli cells. The highest amounts of TGFβ2 protein were secreted in the cocultures and by peritubular cells, whereas Sertoli cells secreted only minor amounts. Stimulation experiments with FSH revealed a reduced secretion of TGFβ2 in cocultures, probably mediated by a paracrine interaction of the FSH-responsive Sertoli cells. In contrast, TGFβ2 secretio...

Prostate specific membrane antigen (PSM) is expressed in various human tissues: implication for the use of PSM reverse transcription polymerase chain reaction to detect hematogenous prostate cancer spread

Abstract Detection of prostate-specific membrane antigen (PSM)-mRNA expression in blood samples using reverse transcription polymerase chain reaction (RT-PCR) is discussed as a new diagnostic marker of circulating micrometastases in prostate cancer patients. We applied the RT-PCR technique to different human tissues and obtained positive signals for PSM transcripts in human genital and multiple extra-genital tissue sites. The cDNAs were prepared from different human tissues and prostatic cell lines. RT-PCR and nested RT-PCR for PSM was performed with primers derived from the published PSM cDNA. The RT-PCR fragments obtained were cloned and showed 100% sequence homology to PSM. Southern blot hybridization with labeled probes was used to confirm the specificity of the amplicons. In addition to the known PSM expression in the human brain, PSM-mRNA was detected in cDNA isolated from human testis, epididymis and seminal vesicles and in the PC-3 prostatic cancer cell line. Furthermore, we found PSM-mRNA in heart, liver, lung, kidney, spleen, and thyroid gland. The results indicate that PSM expression is not restricted to the prostate gland, but represents a more general component of genital and extra-genital human tissues. This must be considered when RT-PCR and nested RT-PCR screening for PSM expression is performed as a diagnostic measure in blood from prostate cancer patients.

Glucocorticoid receptor distribution in rat testis during postnatal development and effects of dexamethasone on immature peritubular cells in vitro

Summary. In this study, the occurrence of the glucocorticoid receptor in the rat testis during early stages of postnatal development and its potential functional significance were investigated. Quantitative analyses of immunohistochemically labelled paraffin sections revealed that the receptor was present during all stages of postnatal development in the nuclei of interstitial cells such as Leydig cells, macrophages and fibroblasts, and endothelial cells of blood vessels. The labelling index increased initially, with maximum levels reached within the second week of postnatal development, and decreased thereafter. Within the seminiferous tubules, the glucocorticoid receptor could be detected in the nuclei of germ cells as well as Sertoli cells, reaching the highest levels in 3‐week‐old rats, mainly due to immature germ cell staining. In contrast, approximately 50% of the peritubular cell nuclei were stained throughout postnatal development. In vitro experiments on immature and immortalized peritubular cells demonstrated a dose‐dependent and significant decrease in proliferation and fibronectin secretion after administration of dexamethasone. The data of this study suggest that glucocorticoids have a consistently repressive effect on peritubular cells throughout postnatal development. In summary, labelling of germ cells, especially in immature rats, might indicate an inhibition of spermatogenesis by corticosteroids.