Anti-inflammatory effects of extracellular cyclosporins are exclusively mediated by CD147

Leukocyte trafficking and recruitment is a critical process in host immune surveillance and in inflammatory diseases. Extracellular cyclophilins (eCyps) have been identified as a novel class of chemotactic mediators. The impact of eCyp/CD147 interactions for the recruitment of leukocytes during inflammation was analyzed using a structurally simplified cell-impermeable eCyp inhibitor. This compound was highly effective at inhibiting leukocyte migration toward CypA in vitro as well as in the recruitment of leukocytes during inflammation in a mouse model of experimentally induced peritonitis and delayed-type hypersensitivity reaction. By using CD147-/- mice in combination with the cell-impermeable eCyp inhibitor, we were able to show that the action of eCyps in inflammation is exclusively mediated by interaction with CD147. Our findings suggest that blocking eCyps may be an effective therapeutic target for reducing inflammatory diseases associated with leukocyte recruitment.

Extracellular matrix collagen alters cell proliferation and cell cycle progression of human uterine leiomyoma smooth muscle cells

Uterine leiomyomas (ULs) are benign tumors occurring in the majority of reproductive aged women. Despite the high prevalence of these tumors, little is known about their etiology. A hallmark of ULs is the excessive deposition of extracellular matrix (ECM), primarily collagens. Collagens are known to modulate cell behavior and function singularly or through interactions with integrins and growth factor-mediated mitogenic pathways. To better understand the pathogenesis of ULs and the role of ECM collagens in their growth, we investigated the interaction of leiomyoma smooth muscle cells (LSMCs) with two different forms of collagen, non-polymerized collagen (monomeric) and polymerized collagen (fibrillar), in the absence or presence of platelet-derived growth factor (PDGF), an abundant growth factor in ULs. Primary cultures of human LSMCS from symptomatic patients were grown on these two different collagen matrices and their morphology, cytoskeletal organization, cellular proliferation, and signaling pathways were evaluated. Our results showed that LSMCs had distinct morphologies on the different collagen matrices and their basal as well as PDGF-stimulated proliferation varied on these matrices. These differences in proliferation were accompanied by changes in cell cycle progression and p21, an inhibitory cell cycle protein. In addition we found alterations in the phosphorylation of focal adhesion kinase, cytoskeletal reorganization, and activation of the mitogen activated protein kinase (MAPK) signaling pathway. In conclusion, our results demonstrate a direct effect of ECM on the proliferation of LSMCs through interplay between the collagen matrix and the PDGF-stimulated MAPK pathway. In addition, these findings will pave the way for identifying novel therapeutic approaches for ULs that target ECM proteins and their signaling pathways in ULs.

Basigin null mutant male mice are sterile and exhibit impaired interactions between germ cells and Sertoli cells

Basigin (BSG) is a multifunctional glycoprotein that plays an important role in male reproduction since male knockout (KO) mice are sterile. The Bsg KO testis lacks elongated spermatids and mature spermatozoa, a phenotype similar to that of alpha-mannosidase IIx (MX) KO mice. MX regulates formation of N-acetylglucosamine (GlcNAc) terminated N-glycans that participate in germ cell-Sertoli cell adhesion. Results showed that Bsg KO spermatocytes displayed normal homologous chromosome synapsis and progression through meiosis. However, only punctate expression of the round spermatid marker SP-10 in the acrosomal granule of germ cells of Bsg KO mice was detected indicating that spermatogenesis in Bsg KO mice was arrested at the early round spermatid stages. We observed a large increase in the number of germ cells undergoing apoptosis in Bsg KO testes. Using lectin blotting, we determined that GlcNAc terminated N-glycans are linked to BSG. GlcNAc terminated N-glycans were significantly reduced in Bsg KO testes. These observations indicate that BSG may act as a germ cell-Sertoli cell attachment molecule. Loss of BSG significantly reduced adhesion between GC-2 and SF7 cells. Moreover, wild type testes showed strong expression of N-cadherin (CDH2) while expression was greatly reduced in the testes of Bsg KO mice. In addition, the integrity of the blood-testis barrier (BTB) was compromised in Bsg KO testes. In conclusion, although some Bsg KO spermatogonia can undergo normal progression to the spermatocyte stage, BSG-mediated germ cell-Sertoli cell interactions appear to be necessary for integrity of the BTB and spermatocyte progression to mature spermatozoa.

Stimulation of GPR30 increases release of EMMPRIN-containing microvesicles in human uterine epithelial cells

CONTEXT

Uterine remodeling is highly dependent on the glycosylated transmembrane protein extracellular matrix metalloproteinase (MMP) inducer (EMMPRIN). Previous studies indicate estradiol can increase EMMPRIN expression in uterine cells and promote subsequent induction of MMP production.

OBJECTIVE

The aim of this study was to investigate the role of G protein-coupled receptor 30 (GPR30) stimulation on EMMPRIN microvesicle release in the human uterine epithelial cell line hTERT-EEC (EECs).

DESIGN

We examined EMMPRIN release by human EECs in response to GPR30 stimulation by microvesicle isolation, Western blot, and immunocytochemistry. We employed a pharmacological approach using the GPR30-selective agonist G1 and the antagonist G15 to determine the receptor specificity of this response.

RESULTS

We demonstrated GPR30 expression in EECs and release of EMMPRIN in microvesicles in response to stimulation of GPR30. G1, estradiol, and cholera toxin stimulated EMMPRIN release in microvesicles as detected by Western blot and immunocytochemistry, indicating that stimulation of GPR30 can induce EMMPRIN microvesicle release.

CONCLUSIONS

These data indicate that EMMPRIN release in microvesicles can be mediated by stimulation of GPR30 in human EECs, suggesting that inappropriate stimulation or expression of this receptor may be significant in uterine pathology.

Validation of the aging hen (Gallus gallus domesticus) as an animal model for uterine leiomyomas

Uterine leiomyomas, or fibroids, are the most frequent gynecological tumors in premenopausal women with as many as 65% of women becoming clinically symptomatic. Uterine fibroids are benign myometrial tumors that produce large quantities of extracellular matrix proteins. Despite its high morbidity, the molecular basis underlying the development of uterine leiomyomas is not well understood. Domestic hens of Gallus gallus domesticus develop oviductal leiomyomas similar to those found in humans. We investigated the natural history of chicken leiomyomas, in vivo expression of protein biomarkers, and in vitro expression of ovarian steroid receptors. Based on the analysis of 263 hens, tumor prevalence, tumor number per hen, and tumor size increased as the hens aged. Immunohistochemistry for alpha-smooth muscle actin (SMA) and desmin confirmed the smooth muscle phenotype of the chicken leiomyomas. Intense collagen expression was detected in these oviductal leiomyomas by Mason's trichrome, and the tumors also showed increased expression of TGFB3 and collagen type I mRNAs. Consistent with human leiomyomas, chicken fibroids displayed increased BCL2 and estrogen (E) and progesterone (P) receptor expression. Chicken leiomyomas were dissociated for in vitro culture. Cells from explants were positive for SMA, desmin, and E and P receptors until the fourth passage. These cells also displayed a response similar to human cells when challenged with halofuginone, an antifibrotic agent. Our findings indicate that the chicken is an excellent complementary model for studies involving the pathophysiology of human uterine leiomyomas.

Role of microRNA-21 and programmed cell death 4 in the pathogenesis of human uterine leiomyomas

OBJECTIVE

To determine whether programmed cell death 4 (PDCD-4) is altered in autologous leiomyoma and myometrial tissues and what microRNA-21's (miR-21) role is in PDCD-4 expression, apoptosis, and translation.

DESIGN

Laboratory research.

SETTING

Academic medical center.

PATIENT(S)

Myometrial and leiomyoma tissues from patients with symptomatic leiomyomata.

INTERVENTION(S)

Tissue analysis and miR-21 knockdown in cultured immortalized myometrial (UtM) and leiomyoma (UtLM) cells.

MAIN OUTCOME MEASURE(S)

MiR-21 and PDCD-4 mRNA and protein expression.

RESULT(S)

Leiomyoma tissues robustly expressed the full-length 51 kd isoform of PDCD-4, but normal myometrial tissue had negligible expression. Consistent with autologous tissues, UtLM cells expressed elevated miR-21 and a similar pattern of PDCD-4 compared with UtM cells. Knockdown of miR-21 increased PDCD-4 levels in UtM cells and UtLM cells, indicating that it can regulate PDCD-4 expression. Loss of miR-21 also increased cleavage of caspase-3 (apoptosis marker) and increased phosphorylation of elongation factor-2 (marker of reduced translation) in both cell lines.

CONCLUSION(S)

Elevated leiomyoma miR-21 levels are predicted to decrease PDCD-4 levels, thus leiomyomas differ from other tumors where loss of PDCD-4 is associated with tumor progression. Our studies indicate regulation of PDCD-4 expression is not a primary miR-21 function in leiomyomas, but instead miR-21 is able to impact cellular apoptosis and translation, through unknown targets, in a manner consistent with its involvement in the pathophysiology of uterine fibroids.

EMMPRIN is secreted by human uterine epithelial cells in microvesicles and stimulates metalloproteinase production by human uterine fibroblast cells

Endometrial remodeling is a physiological process involved in the gynecological disease, endometriosis. Tissue remodeling is directed by uterine fibroblast production of matrix metalloproteinases (MMPs). Several MMPs are regulated directly by the protein extracellular matrix metalloproteinase inducer (EMMPRIN) and also by proinflammatory cytokines such as interleukin (IL)1-α/β. We hypothesized that human uterine epithelial cells (HESs) secrete intact EMMPRIN to stimulate MMPs. Microvesicles from HES cell-conditioned medium (CM) expressed intact EMMPRIN protein. Treatment of HES cells with estradiol or phorbyl 12-myristate-13-acetate increased the release of EMMPRIN-containing microvesicles. The HES CM stimulated MMP-1, -2, and -3 messenger RNA levels in human uterine fibroblasts (HUFs) and EMMPRIN immunodepletion from HES-cell concentrated CM reduced MMP stimulation (P < .05). Treatment of HUF cells with low concentrations of IL-1β/α stimulated MMP production (P < .05). These results indicate that HES cells regulate MMP production by HUF cells by secretion of EMMPRIN, in response to ovarian hormones, proinflammatory cytokines as well as activation of protein kinase C.

Disrupting the EMMPRIN (CD147)-cyclophilin A interaction reduces infarct size and preserves systolic function after myocardial ischemia and reperfusion

OBJECTIVE

Inflammation and proteolysis crucially contribute to myocardial ischemia and reperfusion injury. The extracellular matrix metalloproteinase inducer EMMPRIN (CD147) and its ligand cyclophilin A (CyPA) may be involved in both processes. The aim of the study was to characterize the role of the CD147 and CyPA interplay in myocardial ischemia/reperfusion (I/R) injury.

METHODS AND RESULTS

Immunohistochemistry showed enhanced expression of CD147 and CyPA in myocardial sections from human autopsies of patients who had died from acute myocardial infarction and from mice at 24 hours after I/R. At 24 hours and 7 days after I/R, the infarct size was reduced in CD147(+/-) mice vs CD147(+/+) mice (C57Bl/6), in mice (C57Bl/6) treated with monoclonal antibody anti-CD147 vs control monoclonal antibody, and in CyPA(-/-) mice vs CyPA(+/+) mice (129S6/SvEv), all of which are associated with reduced monocyte and neutrophil recruitment at 24 hours and with a preserved systolic function at 7 days. The combination of CyPA(-/-) mice with anti-CD147 treatment did not yield further protection compared with either inhibition strategy alone. In vitro, treatment with CyPA induced monocyte chemotaxis in a CD147- and phosphatidylinositol 3-kinase-dependent manner and induced monocyte rolling and adhesion to endothelium (human umbilical vein endothelial cells) under flow in a CD147-dependent manner.

CONCLUSION

CD147 and its ligand CyPA are inflammatory mediators after myocardial ischemia and reperfusion and represent potential targets to prevent myocardial I/R injury.

Extracellular matrix metalloproteinase inducer expression in the baboon endometrium: menstrual cycle and endometriosis

Extracellular matrix metalloproteinase inducer (EMMPRIN; BSG) regulates tissue remodeling through matrix metalloproteinases (MMPs). In human and non-human primates, endometrial remodeling is important for menstruation and the pathogenesis of endometriosis. We hypothesized that as in humans, BSG and MMPs are expressed in the endometrium of cycling baboons, and their expression is hormonally regulated by ovarian hormones, but endometriosis disrupts this regulation. BSG expression was evaluated in the baboon endometrium by q-PCR and immunohistochemistry. In the endometrium of control cycling animals, BSG mRNA levels were highest in late secretory stage tissue. BSG protein localized to glandular epithelial cells during the proliferative phase; whereas, secretory stage tissues expressed BSG in glandular and luminal epithelia with weak stromal staining. Several MMPs were differentially expressed throughout the menstrual cycle with the highest levels found during menstruation. In ovariectomized animals, BSG endometrial mRNA levels were highest with treatment of both estrogen and progesterone than that with only estrogen. Estrogen alone resulted in BSG protein localization primarily in the endometrial glandular epithelia, while estrogen and progesterone treatment displayed BSG protein localization in both the glandular and stromal cells. Exogenous hormone treatment resulted in differential expression patterns of all MMPs compared with the control cycling animals. In the eutopic endometrium of endometriotic animals, BSG mRNA levels and protein were elevated early but decreased later in disease progression. Endometriosis elevated the expression of all MMPs except MMP7 compared with the control animals. In baboons, BSG and MMP endometrial expression is regulated by both ovarian hormones, and their expression patterns are dysregulated in endometriotic animals.

Expression of basigin in reproductive tissues of estrogen receptor-{alpha} or -{beta} null mice

Basigin plays important roles in both male and female reproduction because basigin (Bsg) null male and female mice are infertile. The aim of the present study was to determine whether basigin expression in reproductive organs requires estrogen receptor-alpha (ESR1, ERalpha) or -beta (ESR2, ERbeta). Expression of basigin protein in the testis, ovary, and male and female reproductive tracts was studied in adult wild-type (WT), Esr1-null (alphaERKO), and Esr2-null (betaERKO) mice by immunohistochemistry and immunoblotting. Basigin mRNA levels in ovary and uterus were examined by quantitative RT-PCR. In females, basigin protein expression was observed mainly in granulosa and interstitial cells of the ovary and epithelial cells of the proximal oviduct in all genotypes. Basigin protein was also expressed in the uterine epithelium at proestrus and estrus in WT and betaERKO mice but not in alphaERKO mice. However, a higher level of basigin mRNA was observed in uteri of alphaERKO mice compared with WT and betaERKO mice. In males, basigin was expressed in Leydig cells and all germ cells except spermatogonia in all genotypes. Basigin was present in epithelial cells lining the efferent ductules in WT and betaERKO mice, but expression was greatly reduced in alphaERKO mice. In epididymal ducts, basigin expression was observed in epithelial cells in the caput and cauda in all genotypes. These data suggest that expression of basigin protein requires ESR1, but not ESR2, in the uterus and efferent ductules, but is independent of estrogen receptor in the ovary, oviduct, testis, and epididymis.

Reactive oxygen species mediate mitogenic growth factor signaling pathways in human leiomyoma smooth muscle cells

Uterine leiomyomas are benign uterine tumors characterized by extracellular matrix remodeling, increased collagen deposition, and increased smooth muscle cell (SMC) proliferation. The reactive oxygen species (ROS) producing NADPH oxidase complex has been shown to be involved in the signaling pathways of several growth factors, cytokines, and vasoactive agents that stimulate proliferation of a variety of cell types. Our objective was to test the hypothesis that ROS derived from NADPH oxidase is a necessary component of the MAP kinase mitogenic pathway activated by platelet derived growth factor (PDGF) and epidermal growth factor (EGF) in leiomyoma SMCs (LSMCs). Primary cell cultures of LSMCs were used as our experimental model. Our results showed that stimulation of these cells with PDGF or EGF caused a marked increase in intracellular ROS production and that the NADPH oxidase inhibitor, DPI, blocks ROS production. In addition, inhibition of ROS production by NADPH oxidase inhibitors blocked, in a dose-dependent manner, the EGF- and PDGF-induced increase in [(3)H]thymidine incorporation by LSMCs. Furthermore, an exogenous source of ROS, hydrogen peroxide, was sufficient to stimulate [(3)H]thymidine incorporation in LSMCs but did not affect COL1A2 and COL3A1 mRNA levels. Inhibition of the NADPH oxidase complex decreased PDGF-induced MAPK1/MAPK3 activation, whereas exogenous hydrogen peroxide induced MAPK1/MAPK3 activation. This article is the first report suggesting the presence of the NADPH oxidase system and its importance in mitogenic signaling pathways in LSMCs. The necessity of NADPH oxidase-derived ROS for EGF and PDGF signaling pathways leading to cell proliferation points to another potential therapeutic target for treatment and/or prevention of uterine leiomyomas.

Basigin-mediated gene expression changes in mouse uterine stromal cells during implantation

Implantation of mouse embryos is dependent on the proliferation and differentiation of uterine stromal cells in a process called decidualization. Decidualization both supports and limits the invasion of the implanting embryo and is regulated in part by the expression of matrix metalloproteinases (MMPs) and their inhibitors, the tissue inhibitors of metalloproteinases (TIMPs). Molecules that alter the balance between MMP and TIMP expression could prevent implantation of the embryo. The membrane glycoprotein basigin (CD147/EMMPRIN), a known inducer of MMPs, is necessary for normal implantation in the mouse. The purpose of this study was to investigate the potential roles of basigin during implantation in the mouse. Using an in vitro stromal cell culture system, we found that recombinant human basigin protein (rBSG) increases MMP-3 and MMP-9 expression without altering TIMP-3 expression. Our results also showed rBSG induces expression of cytokines IL-1alpha/beta and leukocyte chemoattractants, CCL3, CCL20, CXCL2, and CXCL5. More importantly, rBSG significantly suppressed stromal cell decidualization as shown by the inhibition of alkaline phosphatase-2 expression and activity by rBSG. However, rBSG did not affect stromal cell proliferation. Taken together, our data indicate that basigin mediates gene expression changes in mouse uterine stromal cells and suggests that temporal and spatial regulation of basigin expression may be involved in the recruitment of leukocytes to the mouse uterus during early pregnancy.

The antifibrotic drug halofuginone inhibits proliferation and collagen production by human leiomyoma and myometrial smooth muscle cells

OBJECTIVE

To investigate the effects of the antifibrotic drug halofuginone on extracellular matrix production, cell proliferation, and apoptosis of cultured myometrial and leiomyoma smooth muscle cells.

DESIGN

Comparative and controlled experimental research study.

SETTING

University research laboratory.

PATIENT(S)

Leiomyoma and myometrial tissues were obtained from eight different patients at the time of elective hysterectomy.

MAIN OUTCOME MEASURE(S)

The effects of halofuginone on cell proliferation were assessed by tritiated thymidine uptake assays and cell count assays. Effects on TGFbeta1, collagen type I, and collagen type III mRNA levels were assessed by quantitative real-time polymerase chain reaction. Effects on apoptosis were assayed using a chemiluminescent assay to measure changes in caspase 3 and 7.

RESULT(S)

Halofuginone inhibited cell proliferation of both leiomyoma and autologous myometrial cells in a dose-dependent manner by inhibiting DNA synthesis within 24 hours and later inducing apoptosis (as measured by increased caspase 3/7) by 48-72 hours. Halofuginone also significantly reduced collagen type I (alpha1) and collagen type III (alpha1) mRNA levels, as well as the profibrotic factor TGFbeta1 mRNA levels in both cell types.

CONCLUSION(S)

These results provide evidence to support the use of the antifibrotic drug halofuginone as a novel drug treatment for uterine leiomyomas.

Basigin-2 is a cell surface receptor for soluble basigin ligand

The metastatic spread of a tumor is dependent upon the ability of the tumor to stimulate surrounding stromal cells to express enzymes required for tissue remodeling. The immunoglobulin superfamily protein basigin (EMMPRIN/CD147) is a cell surface glycoprotein expressed by tumor cells that stimulates matrix metalloproteinase and vascular endothelial growth factor expression in stromal cells. The ability of basigin to stimulate expression of molecules involved in tissue remodeling and angiogenesis makes basigin a potential target for the development of strategies to block metastasis. However, the identity of the cell surface receptor for basigin remains controversial. The goal of this study was to determine the identity of the receptor for basigin. Using a novel recombinant basigin protein (rBSG) corresponding to the extracellular domain of basigin, it was demonstrated that the native, nonglycosylated rBSG protein forms dimers in solution. Furthermore, rBSG binds to the surface of uterine fibroblasts, activates the ERK1/2 signaling pathway, and induces expression of matrix metalloproteinases 1, 2, and 3. Proteins that interact with rBSG were isolated using a biotin label transfer technique and sequenced by matrix-assisted laser desorption ionization tandem mass spectrophotometry. The results demonstrate that rBSG interacts with basigin expressed on the surface of fibroblasts and is subsequently internalized. During internalization, rBSG associates with a novel form of human basigin (basigin-3). It was concluded that cell surface basigin functions as a membrane receptor for soluble basigin and this homophilic interaction is not dependent upon glycosylation of the basigin ligand.

Changes in small intestinal nutrient transport and barrier function after lipopolysaccharide exposure in two pig breeds

Specific pig breeds with unique characteristics have been developed, and the current study sought to characterize some of these differences. Using modified Ussing chambers, electrophysiological mucosal transport of D-glucose, L-Gln, L-Pro, L-Arg, L-Thr, and glycylsarcosine was assessed in small intestinal tissues (duodenum, jejunum, ileum) taken from Yorkshire-based hybrid (BW = 142.4 +/- 2.0 kg; mean age = 8 mo) and Meishan (BW = 65.8 +/- 0.8 kg; mean age = 6 mo) female pigs after 4 h of lipopolysaccharide (LPS) exposure. Gilts were randomly assigned to control (saline infusion; n = 6 Yorkshires, n = 5 Meishans) or LPS (n = 7 Yorkshires, n = 5 Meishans) groups. Therefore, treatments were arranged in a 2 (breed) x 2 (LPS infusion) factorial. Four hours after infusions, pigs were euthanized, and intestinal segment samples were removed. Glucose transport in the ileum was decreased (P < 0.001) in Yorkshires with LPS but was increased (P < 0.001) by over 2-fold in Meishans with LPS. After LPS infusion, Pro transport was increased in duodenum (over 5-fold; P = 0.04) and ileum (over 10-fold; P < 0.001) of Meishans but was unaffected in Yorkshires. Arginine transport in the ileum of control Meishans was greater (P = 0.05) than Arg transport in control Yorkshires. Glycylsarcosine transport was greater (P = 0.02) in Meishans than Yorkshires (nearly 2-fold), regardless of LPS provision. Glycylsarcosine transport was increased (P = 0.003) over 2-fold by LPS, regardless of pig breed. Resistance (barrier function) was increased (P = 0.03) by LPS in Yorkshires but was unaffected in Meishans. The current study indicates that small intestinal function responded differently to LPS in Yorkshire and Meishan gilts and that these effects were nutrient- and segment-dependent.

Expression of extracellular matrix metalloproteinase inducer and matrix metalloproteinases during mouse embryonic development

Mouse embryo implantation is a highly invasive and controlled process that involves remodeling and degradation of the extracellular matrix of the uterus. Matrix metalloproteinases (MMPs) are the main proteinases facilitating this process. Extracellular matrix metalloproteinase inducer (EMMPRIN) can stimulate the production of MMPs and is required for successful implantation in the mouse. The aims of the present study were to examine the expression profiles of mRNA and proteins for EMMPRIN and MMPs in the developing mouse embryoin vitro, and to study whether EMMPRIN protein induces the production of MMPs by mouse blastocysts. EMMPRIN mRNA, detected by RT-PCR, was present at all stages of embryo development from the one-cell to the blastocyst outgrowth. EMMPRIN protein, observed by confocal microscopy, was present on the cell surface at the same stages of development as was the mRNA. Of seven MMPs studied, murine collagenase-like A (Mcol-A), murine collagenase-like B (Mcol-B) and gelatinase A (MMP-2) mRNAs were detected only in blastocyst outgrowths by RT-PCR. Gelatinase B (MMP-9) mRNA was detected both in expanded blastocysts and blastocyst outgrowths. MMP-2 and -9 proteins were detected in the cytoplasm of outgrowing trophoblast cells. Collagenase-2 (MMP-8), collagenase-3 (MMP-13), or stromelysin-1 (MMP-3) mRNAs were not present at any stage of pre- or peri-implantation mouse embryo development. Quantitative RT-PCR analyses showed that recombinant EMMPRIN protein did not stimulate MMP-2 or -9 expression by mouse blastocyst outgrowths. These data suggest that EMMPRIN may regulate physiological functions other than MMP production by mouse embryos during implantation.

Cytokines regulate matrix metalloproteinases in human uterine endometrial fibroblast cells through a mechanism that does not involve increases in extracellular matrix metalloproteinase inducer

PROBLEM

Endometriosis is the presence of ectopic uterine endometrial tissue in the peritoneal cavity. Peritoneal fluid samples of women with endometriosis show elevated interleukin-1 (IL-1)beta, tumor necrosis factor (TNF)-alpha and transforming growth factor (TGF)-beta(1) levels, indicating that an altered immune system may play an important role in the pathogenesis of endometriosis. The invasion of ectopic endometrium into peritoneal mesothelium requires matrix metalloproteinases (MMPs) for tissue remodeling. Several MMPs are differentially expressed in human uterine endometrium with menstrual endometrium showing the highest level of expression. MMPs are stimulated by cytokines and also by the protein Extracellular Matrix Metalloproteinase Inducer (EMMPRIN).

METHOD OF STUDY

To determine the role of cytokines in ectopic endometrial invasion, we investigated whether cytokines could regulate MMP production by endometrial fibroblast cells and whether this stimulation occurred through an effect on EMMPRIN expression. Human uterine fibroblasts (HUF) were treated with IL-1beta, TGF-beta(1) and TNF-alpha in a dose dependent and time dependent manner (C, 0.1, 1, 10 ng/mL IL-1beta or TGF-beta(1); C, 2, 10, 50 ng/mL TNF-alpha) for 0, 6, 12, and 24 hr. Cell conditioned medium samples were collected and concentrated at each timepoint for immunoblot analysis. Cellular RNA was collected for real time PCR analysis of MMPs-1, -2, -3 and EMMPRIN mRNA levels.

RESULTS

Our results showed that IL-1beta stimulated MMP-1 protein secretion and mRNA levels in a time dependent manner (P < 0.05), MMP-2 mRNA in a time dependent manner and MMP-3 in a time and dose dependent manner. TNF-alpha stimulated MMP-1 and -3 protein secretion in a time dependent manner and stimulated MMP-1, -2 and -3 mRNA levels in a time dependent manner (P < 0.05). Neither IL-1beta nor TNF-alpha treatment affected MMP-2 protein secretion. TGF-beta(1) inhibited MMP-1 and MMP-2 mRNAs at the highest treatment dose after 24 hr but there was no effect on protein secretion. TGF-beta(1) exerted no effect on MMP-3 mRNA or protein secretion (P < 0.05). Neither of the cytokines affected EMMPRIN protein or mRNA levels but the 10 ng/mL TGF-beta(1) treatment did cause a reduction in EMMPRIN mRNA levels.

CONCLUSIONS

These data show that elevated cytokines may play a role in the establishment of ectopic endometrium in the peritoneal cavity by stimulating MMPs to remodel the mesothelial lining of the peritoneum thus allowing for tissue invasion. The stimulation of MMPs by cytokines occurred without any change in EMMPRIN expression whereas the inhibitory effect of TGF-beta(1) involved a reduction in EMMPRIN mRNA levels.

Tissue distribution of basigin and monocarboxylate transporter 1 in the adult male mouse: a study using the wild-type and basigin gene knockout mice

Basigin (Bsg) is a transmembrane protein that is responsible for targeting of monocarboxylate transporters (MCTs) to the cell membrane. The present study was conducted to determine whether or not Bsg was required for the proper localization of MCT isoform 1 (MCT1) in a wide range of tissues in adult male mice. The tissue distributions of Bsg and MCT1 in wild-type (WT) mice, the tissue distribution of MCT1 in Bsg gene knockout (Bsg-KO) mice, and the protein and mRNA levels of MCT1 in both genotypes were studied. Immunohistochemistry demonstrated that Bsg colocalized with MCT1 in the cerebrum, retina, skeletal and cardiac muscle, duodenal epithelium, hepatic sinusoid, proximal uriniferous tubules, Leydig cells, and efferent ductule epithelium in WT mice. Bsg was absent but MCT1 was present in Sertoli cells, cauda epididymis, myoepithelial cells and duct of the mandibular gland, surface epithelium of the stomach and bronchioles. In Bsg-KO mice, with the exception of Leydig cells, MCT1 immunostaining was greatly reduced in intensity and its distribution was altered in tissues that expressed both Bsg and MCT1 in WT mice. Levels of the protein and mRNA for MCT1 in these tissues did not change significantly in Bsg-KO mice. On the other hand, immunostaining patterns in cells in which Bsg was absent but MCT1 was present in WT mice remained unchanged in Bsg-KO mice. These observations suggest that Bsg is required for the proper localization of MCT1 in a wide range of cells but not in every cell type.

Extracellular matrix metalloproteinase inducer regulates metalloproteinases in human uterine endometrium

CONTEXT

Endometrial remodeling occurs during each menstrual cycle in women and also during the establishment of endometriosis. Both processes involve the production of metalloproteinases (MMPs) by uterine endometrial cells.

OBJECTIVE

The objective of this study was to determine whether tissue remodeling and endometrial invasion involve activation of MMPs by extracellular matrix metalloproteinase inducer (EMMPRIN).

MAIN OUTCOME MEASURES

EMMPRIN expression was examined by immunohistochemistry and real-time PCR in ectopic and eutopic endometria. For functional assays, human uterine fibroblasts were treated in the absence or presence of IL-1beta (10 ng/ml) or purified native EMMPRIN (0.5 or 1 microg/ml) for 24 h. Cellular RNA and conditioned medium were assayed by real-time PCR or immunoblotting.

RESULTS

EMMPRIN protein localized to epithelial and fibroblast cells of eutopic and ectopic endometria. The pattern of localization was regulated by ovarian hormones. EMMPRIN mRNA levels varied throughout the menstrual cycle in parallel with the cyclic changes in estradiol. EMMPRIN treatment (0.5 microg/ml) of human uterine fibroblast cells stimulated MMP-1 (5.23-fold) and MMP-2 (8.55-fold), but not MMP-3, mRNA levels over levels in control cells (P < 0.05). EMMPRIN treatment (1 microg/ml) stimulated endogenous EMMPRIN (1.6-fold) mRNA levels (P > 0.05). IL-1beta stimulated MMP-1 (5.6-fold), MMP-2 (2.8-fold), and MMP-3 (75-fold) gene expression, but not EMMPRIN, over levels in control cells (P < 0.05). Both EMMPRIN and IL-1beta treatments stimulated MMP-1, -2, and -3, but not EMMPRIN protein secretion, with 0.5 microg/ml producing the greatest response.

CONCLUSIONS

The ability of EMMPRIN to stimulate MMP secretion by endometrial fibroblasts indicates its potential role in uterine remodeling and the pathogenesis of endometriosis.

Estrogen induces CCN5 expression in the rat uterus in vivo

Estrogen plays an important role in the normal physiology as well as various pathologies of the uterus. Given the nature of uterine remodeling during the reproductive cycle and pregnancy, we sought to determine whether CCN5, a gene that we have shown to be important in smooth muscle cell proliferation and migration, is an estrogen-induced gene in the uterus. In the present study, we demonstrate that levels of CCN5 mRNA and protein expression were 5-fold higher in uteri from proestrous females relative to metestrous females, a finding consistent with estrogen induction of the CCN5 gene. Ovariectomized rats treated with exogenous estrogen or estrogen and progesterone exhibited 4- to 8-fold higher levels of CCN5 mRNA and protein than animals treated with either progesterone or vehicle alone. Analysis of rat uterine sections using immunohistochemistry demonstrates CCN5 localization throughout the uterus, including the endometrium and endometrial glands as well as the myometrium. Thus, our data indicate that CCN5 is positively regulated by estrogen in the rat uterus and suggests that this gene may play an important role in maintaining normal uterine physiology.

The growth arrest-specific gene CCN5 is deficient in human leiomyomas and inhibits the proliferation and motility of cultured human uterine smooth muscle cells

Uterine fibroids (leiomyomas) are a major women's health problem. Currently, the standard for treatment remains hysterectomy, since no other treatment modalities can reduce both symptoms and recurrence. As leiomyomas are benign neoplasias of smooth muscle cells, we sought to understand the regulation of uterine smooth muscle cell mitogenesis by CCN5, a growth arrest-specific gene in vascular smooth muscle cells which is induced and maintained by heparin treatment. Using autologous human myometrial and leiomyoma smooth muscle cells, we demonstrate that the proliferation and motility of both cell types are inhibited by the overexpression of CCN5. Surprisingly, we show that even though CCN5 is induced by heparin in vascular smooth muscle cells, treatment with heparin does not induce CCN5 expression in human uterine smooth muscle cells. Furthermore, we examine CCN5 mRNA expression in 10 autologous pairs of human myometrial and leiomyoma tissues and determine that CCN5 is down-regulated in 100% of the leiomyoma tissues analysed when compared to their normal myometrial counterparts. Thus, our data strongly suggest that CCN5 may exert an important function in maintaining the normal uterine phenotype and that loss of the anti-proliferative protein CCN5 from normal myometrium may account, at least in part, for tumorigenesis.

HMGA2 expression in uterine leiomyomata and myometrium: quantitative analysis and tissue culture studies

The high mobility group gene, HMGA2, is frequently expressed in uterine leiomyomata (UL) with chromosomal rearrangements of 12q15. In contrast, HMGA2 expression has not been detected in karyotypically normal UL or in myometrium, but has been detected in these tissues after culture. To characterize further the expression pattern of HMGA2, we assessed HMGA2 expression by RT-PCR followed by Southern blot hybridization, and by real-time PCR in three tissue panels: (1) primary myometrial cultures, (2) uncultured tissue from 15 karyotypically normal samples consisting of eleven 46,XX UL and four matched myometrial specimens, and (3) uncultured tissue from ten UL with 12q15 rearrangements and three matched myometrial specimens. HMGA2 expression was detected in all samples from the three panels. The level of HMGA2 expression in karyotypically normal UL was similar to the level of expression in myometrium; however, it was significantly less than the level measured in UL with 12q15 rearrangements. This expression analysis by use of detection methods of different sensitivities underscores the importance of studies of HMGA2 expression in uncultured tissues and of careful interpretation of results from experiments on cultured cells. Moreover, detection of HMGA2 expression in myometrium and in UL without 12q15 rearrangements, tissues previously thought not to express HMGA2, suggests that HMGA2 expression is required in normal adult myometrial physiology.

Heparin inhibits the motility and proliferation of human myometrial and leiomyoma smooth muscle cells

Uterine fibroids (leiomyomas) are a major women's health problem. Currently, the standard for treatment remains hysterectomy, because no other treatment modalities can reduce both symptoms and recurrence. As leiomyomas are a hyperproliferation of smooth muscle cells, we sought to understand the regulation of uterine smooth muscle cell mitogenesis by the glycosaminoglycan heparin, which has been extensively studied as an anti-proliferative molecule in vascular smooth muscle cells. Using matched pairs of human myometrial and leiomyoma smooth muscle cells from the same uterus, we demonstrate that the proliferation and motility of both cell types are inhibited by heparin. We report that the decrease in cell number seen in the presence of heparin is not because of cell death. Interestingly, there is significant patient-to-patient variability in the proliferation response but not in the motility response to heparin. Furthermore, nonanticoagulant and anticoagulant heparin were equally effective at inhibiting leiomyoma and myometrial smooth muscle cell proliferation. These results warrant further investigation into the possibility that heparin might be useful in the treatment of uterine fibroids.

Granulocyte macrophage colony-stimulating factor in adenomyosis and autologous endometrium

OBJECTIVE

Granulocyte macrophage colony-stimulating factor (GM-CSF) has been related to macrophage recruitment and activation and has been identified in the human endometrium. We determined whether adenomyosis expresses GM-CSF, and if present, compared GM-CSF protein expression in adenomyosis with that in autologous endometrium.

METHODS

We examined ectopic and eutopic endometrium from 16 premenopausal women who had hysterectomies for abnormal uterine bleeding, pelvic pain, or uterine prolapse. Serial sections of premenopausal uteri containing endometrium and adenomyosis were analyzed by immunohistochemistry for GM-CSF ligand and receptor and CD68 macrophages. We analyzed the intensity of staining for GM-CSF ligand and receptor and macrophages in the glandular epithelium and stroma of adenomyosis and autologous endometrium.

RESULTS

The GM-CSF ligand localized primarily in the glandular epithelium and myometrium with only light stromal staining. Staining for GM-CSF ligand was significantly higher in adenomyotic glands compared with autologous endometrial glands (P = .002), especially during the secretory phase of the menstrual cycle. There were no statistical differences in the amount and intensity of staining of the GM-CSF receptor in adenomyosis and autologous endometrium. Adenomyotic tissue contained significantly more macrophages than matched autologous endometrium (P = .0004).

CONCLUSIONS

Adenomyotic glandular epithelium had greater expression of the GM-CSF ligand compared with autologous endometrium from premenopausal women, which indicates that GM-CSF may play a role in increasing the levels of activated macrophages in women with adenomyosis.

Adenomyosis demonstrates increased expression of the basic fibroblast growth factor receptor/ligand system compared with autologous endometrium

OBJECTIVES

Basic fibroblast growth factor (bFGF) is an angiogenic growth factor present in human endometrium and myometrium. Women with leiomyoma-related abnormal uterine bleeding have local dysregulation of bFGF and its type 1 receptor (FGF-R). This study was designed to evaluate if adenomyosis expresses bFGF and FGF-R, and if present, to compare bFGF and FGF-R expression in adenomyosis and autologous endometrium.

DESIGN

Menopausal uteri containing endometrium and adenomyosis were analyzed using immunohistochemistry with monoclonal antibodies specific for bFGF, FGF-R, and proliferating cell nuclear antigen (PCNA), a marker of cellular proliferation. The expression and intensity of staining for bFGF, FGF-R, and PCNA were evaluated in the glandular epithelium and stroma of adenomyosis and endometrium.

RESULTS

Glandular epithelial staining was significantly greater in adenomyosis compared with autologous endometrium for bFGF and FGF-R. Stromal staining for bFGF and PCNA was significantly increased in adenomyosis compared with autologous endometrium.

CONCLUSIONS

Upregulation of the bFGF receptor/ligand system and increased cellular proliferation in adenomyosis may contribute to the pathogenesis of abnormal uterine bleeding associated with adenomyosis.

Identification of new therapies for leiomyomas: what in vitro studies can tell us

Leiomyomas are a significant problem in women's health. An understanding of the biology of these tumors and how their growth is regulated is emerging from in vitro studies using tissue specimens and cultured cells. These studies have clarified how the ovarian steroid hormones regulate growth of uterine SMCs and how the ovarian steroid ligand-receptor system has been altered in leiomyomas. Such information will allow investigators to identify steroid hormone antagonists and steroid hormone receptor modulators that may be useful for treatment of leiomyomas. We are now also developing a much better understanding of the growth factors that are produced by SMCs of leiomyoma tumors. These growth factors not only regulate the proliferation, apoptosis, and extra-cellular matrix production of the SMCs but also regulate proliferation and migration of vascular endothelial cells. Targeting these growth factors and their receptors can reduce leiomyoma growth through two different mechanisms. One targets the SMCs and the other targets the vascular system that supports the growth of the tumor. Another important lesson that can be learned from reading the scientific literature is that there are striking similarities between the biology of uterine leiomyomas and other pathologic diseases that involve mesenchymally derived cells. These include benign keloids, other fibrotic diseases such as pulmonary fibrosis, and vascular diseases such as atherosclerosis. Compounds that are developed to treat these conditions may also be beneficial for treatment of uterine leiomyomas. The next few years will undoubtedly yield many new drug discoveries for these diseases.

Human leiomyoma smooth muscle cells show increased expression of transforming growth factor-beta 3 (TGF beta 3) and altered responses to the antiproliferative effects of TGF beta

Transforming growth factor-betas (TGF betas) are multifunctional peptides that regulate growth and differentiation in a variety of cells. The goals of this study were to compare expression of the TGF beta isoforms in normal myometrium and benign leiomyoma tumors of the uterus and to examine the effects of TGF betas on cell proliferation and collagen production by these cells in vitro. Myometrium and leiomyoma tissues were obtained from patients undergoing elective hysterectomies. Tissues were processed for ribonucleic acid (RNA) and were also established as primary cell cultures. Northern blot analysis showed that the levels of TGF beta 1 messenger RNAs (mRNAs) were similar between leiomyoma and myometrium, whereas leiomyoma showed 5-fold higher levels of expression of TGF beta 3 mRNA than autologous myometrium. Expression of TGF beta 3 protein detected by immunohistochemistry was much more intense in leiomyoma tissues than in corresponding myometrium. Levels of both TGF beta 1 and TGF beta 3 increased with increasing cell density for leiomyoma and myometrium smooth muscle cells cultured in vitro. Effects of TGF beta 1 and TGF beta 3 on cell proliferation were assessed by measuring changes in DNA synthesis with the tritiated thymidine incorporation assay. The doses of TGF betas tested were 0, 0.1, 1.0, and 10.0 ng/mL. All three doses of TGF beta 1 and TGF beta 3 inhibited DNA synthesis in myometrium smooth muscle cells by 31--54%. Concomitant treatment with an immunoneutralizing antibody to TGF beta 1--3 reversed this inhibitory effect. In contrast, TGF beta 1 had no effect on leiomyoma smooth muscle cells, whereas TGF beta 3 increased DNA synthesis by leiomyoma cells. Combined treatment with the immunoneutralizing antibody prevented this increase. Treatment of leiomyoma and myometrial cells with the TGF beta immunoneutralizing antibody for 24 h caused a 45--60% reduction in collagen type I and type III mRNA levels, suggesting that endogenous TGF betas are important for collagen production. These results support the hypothesis that alterations in the TGF beta system produce loss of sensitivity to the antiproliferative effects of TGF beta, and increased expression of TGF beta 3 may contribute to the growth of these tumors.

Novel therapeutic strategies for leiomyomas: targeting growth factors and their receptors

Leiomyomas (fibroids) are benign smooth-muscle cell (SMC) tumors of the uterus and are the most common pelvic tumors in women. These tumors occur primarily during the reproductive years and are the most common indication for hysterectomy in women. Unfortunately the only effective treatments for leiomyomas and the associated abnormal uterine bleeding are surgical, involving either hysterectomy, myomectomy, or hysteroscopic removal of the tumors. The goal of this paper is to discuss recent research findings that support the idea of using therapeutic compounds that block the actions of specific growth factors as therapeutic agents for treatment of leiomyomas and abnormal uterine bleeding. Most of the studies were carried out using cell cultures of leiomyoma or myometrial SMCs. Primary cultures of SMCs provide a system for investigation of the roles of growth factors and their receptors in proliferation of normal myometrial and leiomyoma SMCs. Several growth factors have been shown to be present and to have regulatory roles in the proliferation of uterine SMCs. Bioassay and Western blotting of fast protein liquid chromatography fractions of tissue extracts identified platelet-derived growth factor, heparin-binding epidermal growth factor, hepatoma-derived growth factor, and basic fibroblast growth factor in normal myometrium and fibroid tumors. The presence of heparin-binding growth factors suggests a possible focus for therapeutic agents. RG13577 (a heparinlike compound) and halofuginone (an alkyloid) reversibly inhibited DNA synthesis of normal myometrial and leiomyoma cells without toxic effects. Pirfenidone, a known antifibrotic drug, inhibited DNA synthesis and synthesis of collagen type I mRNA in normal and fibroid cells, and decreased collagen type III mRNA only in normal myometrial cells. Another hopeful therapeutic candidate, interferon-Alpha, significantly inhibited growth factor-stimulated proliferation in both normal and leiomyoma cells. These results suggest that future nonsurgical treatments for leiomyomas may include compounds that block the actions of specific growth factors that regulate proliferation and collagen production by uterine SMCs.

Prolactin is an autocrine or paracrine growth factor for human myometrial and leiomyoma cells

OBJECTIVE

To test the hypothesis that prolactin (PRL) acts as a mitogenic growth factor for human leiomyoma and myometrial cells.

METHODS

To test this hypothesis, we performed three different types of experiments. First, we assessed whether exogenous PRL acted as a mitogen for cultured uterine smooth muscle cells. Second, we examined the role of endogenous PRL by assessing the cell number after exposure of the cultures to a neutralizing antibody to PRL. Finally, we examined both fresh tissues and cultured cells for expression of the PRL receptor messenger ribonucleic acid using the techniques of reverse-transcriptase polymerase chain reaction and Southern blotting.

RESULTS

A significant suppression in cell number was seen after 5 days of culture for leiomyoma cells but not for myometrial cells after treatment with exogenous PRL. Both cell types showed a significant decrease in cell number after treatment with anti-PRL antibody. A 893-bp segment consistent with the cytoplasmic domain of the long form of the PRL receptor was amplified from both fresh and cultured tissues and confirmed by Southern blotting and sequencing.

CONCLUSIONS

PRL appears to be an autocrine or paracrine growth factor for both leiomyoma and myometrial cells. However, there are some differences between tissues in their sensitivity to this growth factor.

HMGIC expression in human adult and fetal tissues and in uterine leiomyomata

The high-mobility-group (HMG) protein gene, HMGIC, is localized to chromosome 12, band q15, a region often rearranged in benign mesenchymal tumors, including uterine leiomyomata. Although some evidence suggests a role in regulation of cell proliferation, the precise function of HMGIC in the development or progression of these tumors remains unclear. We investigated HMGIC expression in 17 fetal tissues (adrenal, aorta, bone, brain, heart, intestine, kidney, liver, lung, muscle, ovary, placenta, skin, spleen, stomach, testis, and uterus) and 10 adult tissues (aorta, brain, cerebellum, fat, kidney, liver, lung, lymph node, myometrium, and spinal cord) by Northern blot and reverse transcriptase-polymerase chain reaction (RT-PCR) assays. Comparisons between HMGIC gene expression in tumor samples from 11 uterine leiomyomata and 7 normal matched myometrium or in vitro cell cultures (chorionic villi, placenta, myometrium, leiomyoma, and skin) were also performed. The gene was expressed in all fetal tissues tested but only in adult lung and kidney. HMGIC was also expressed in leiomyoma tumor samples containing t(12;14) and in all in vitro cell cultures. The pattern of HMGIC expression suggests that this gene is important in rapidly proliferating human fetal tissues. Restoration of expression in leiomyomata required dysregulation of HMGIC. Transcripts of HMGIC can also be detected after in vitro cell culture, suggesting that HMGIC expression may be affected by factors present in culture media and serum. Genes Chromosomes Cancer 25:316-322, 1999.

Onapristone suppresses prolactin production in explant cultures of leiomyoma

OBJECTIVE

To assess the action of onapristone, a type I antiprogestin, on prolactin (PRL) production by explant cultures of leiomyoma and myometrium.

DESIGN

Explant cultures of myometrium and leiomyomas from 3 premenopausal women undergoing hysterectomy in the proliferative phase of the menstrual cycle.

MAIN OUTCOME MEASURES

PRL secretion measured by radioimmunoassay.

RESULTS

PRL secretion was decreased in leiomyomas by onapristone. There was no effect in the myometrium. There was no additional effect with the addition of the type II antiprogestin mifepristone (RU 486).

CONCLUSION

PRL production is suppressed in leiomyomas but not in myometrium after treatment with onapristone in vitro. This suppression may serve as a marker for the clinical effectiveness of agents used in the treatment of leiomyomas.

Fibroids: pathophysiology and current medical treatment

Uterine leiomyomas, or fibroids, are a major cause of abnormal uterine bleeding in women. These benign tumours develop during the reproductive years and their growth has been shown to be dependent on the ovarian steroid hormones oestradiol and progesterone. The growth promoting effects of these steroid hormones appear to be mediated through the local production of specific growth factors. Traditional treatment for leiomyomas has been surgical removal through either hysterectomy or myomectomy. Newer surgical techniques, such as hysteroscopic removal of leiomyomas, endometrial ablation, or uterine arterial embolization, are now being tested as effective but less invasive methods of treatment. Non-surgical treatment of leiomyomas has been primarily through the use of gonadotrophin-releasing hormone agonists which suppress circulating oestradiol and progesterone levels by shutting down the pituitary-ovarian axis. The suppression in steroid hormone levels results in significant fibroid shrinkage, but long-term use of these compounds is not recommended because patients suffer significant bone loss. New antisteroidal compounds, such as the antiprogestin RU 486 and the selective oestrogen-receptor modulator raloxifene, are now being tested as possible therapeutic agents for fibroids.

Messenger ribonucleic acid for the gonadal luteinizing hormone/human chorionic gonadotropin receptor is not present in human endometrium

OBJECTIVE

To determine whether messenger RNA for the gonadal LH/hCG receptor is present in human endometrium with the use of reverse-transcriptase polymerase chain reaction.

DESIGN

In vitro experiment.

SETTING

Academic medical center.

PATIENT(S)

Premenopausal women who were not receiving hormonally active medications and who were undergoing hysterectomy for uterine leiomyomas, menorrhagia, pelvic pain, or uterine prolapse.

INTERVENTION(S)

Tissue from hysterectomy specimens was processed for RNA and treated with deoxyribonuclease where appropriate, and RNA was reverse-transcribed to complementary DNA.

MAIN OUTCOME MEASURE(S)

An appropriately sized band after reverse-transcriptase polymerase chain reaction, followed by sequencing to confirm the results.

RESULT(S)

A primer pair that spanned the extracellular domain was unable to amplify receptor complementary DNA from human endometrial tissue. For a primer pair that spanned transmembrane regions 2-6 of the receptor and was contained wholly in exon 11, a 552-base pair fragment was amplified successfully in 19 of 25 human endometrial samples.

CONCLUSION(S)

The traditional gonadal LH/hCG receptor does not appear to be present in human endometrial tissue. The presence of a portion of the transmembrane part of the molecule suggests that human endometrium may express a truncated or variant form of the receptor.

Transforming growth factor-beta stimulates mouse blastocyst outgrowth through a mechanism involving parathyroid hormone-related protein

The goals of this study were 1) to compare the effects of transforming growth factor-beta (TGF-beta) and parathyroid hormone-related protein (PTHrP) on mouse blastocyst attachment and outgrowth in vitro, 2) to determine whether TGF-beta acts through a mechanism involving PTHrP, 3) to examine effects of PTHrP on preimplantation mouse embryo development, and 4) to determine the pattern of expression of PTHrP protein in the uterus of the mouse during early gestation. In the first set of experiments, hatched blastocysts were placed in fibronectin-coated wells. Cultures were treated with PTHrP or TGF-beta1 and assessed at 24, 48, and 72 h for attachment and surface area of blastocyst outgrowth. Results showed that both PTHrP and TGF-beta1 increased blastocyst outgrowth significantly. A PTHrP-neutralizing antibody blocked the stimulatory effect of both PTHrP and TGF-beta1, suggesting that TGF-beta1 acts to increase endogenous production of PTHrP by the blastocyst. Immunoassay of conditioned medium from blastocysts treated with either TGF-beta1 or PTHrP 1-34 confirmed a 3- to 4-fold increase in levels of PTHrP 1-141. In the second series of experiments, pronuclear zygotes were cultured in various concentrations of PTHrP for 96 h. Blastocysts then were subjected to differential fluorescent staining of inner cell mass and trophectoderm cells. Treatment of mouse embryos with the various concentrations of PTHrP altered neither the number developing to the blastocyst stage nor the number of inner cell mass or trophectoderm cells in the resulting blastocysts. In the third experiment, pregnant mice were killed at Days 3, 4, 5, 6, and 7 of gestation, and uterine horns were processed for immunohistochemistry. Uterine sections were stained with antibodies to PTHrP, desmin, and laminin. On Days 3, 4, and 5, uterine luminal and glandular epithelial cells stained intensely for PTHrP, while stromal cells were negative. By Days 6 and 7, decidualized stromal cells stained positively for PTHrP, desmin, and laminin. These results support the hypothesis that TGF-beta and PTHrP play an important role in the process of implantation.

New concepts in the treatment of uterine leiomyomas

Uterine leiomyomas are a common clinical occurrence for gynecologists. The current approach to treating these neoplasms is shaped by classic surgical principles and the knowledge that these tumors are responsive to the gonadal steroids estrogen and progesterone. As knowledge of leiomyomas advances through the techniques of molecular biology and molecular genetics, new concepts are developed that go beyond just myomas as steroid-responsive tumors. Understanding the molecular events involved in the transformation of a normal myometrial cell into a neoplastic cell and the subsequent growth of these leiomyoma cells will be important in determining the pathogenesis of these tumors and providing new targets for treatment. Knowing the role of peptide growth factors, including basic fibroblast growth factor and transforming growth factor-beta, in the pathogenesis of leiomyoma-related symptoms might lead to new treatments targeting these molecules or their receptors. As the effects of genes, including HMGIC and HMGI(Y), are determined; new treatments to prevent leiomyoma formation or growth may be developed. As we gain understanding of the molecular events that cause benign gynecologic conditions such as leiomyomas, safer and more effective treatments might be found as we enter the 21st century.

Increased expression of stromelysin 3 mRNA in leiomyomas (uterine fibroids) compared with myometrium

OBJECTIVE

To determine the level of expression of selected matrix metalloproteinases in uterine leiomyoma compared with unaffected myometrium in an effort to explain the abnormal accumulation of extracellular matrix in the leiomyoma.

METHODS

The levels of matrix metalloproteinase (MMP) mRNA in leiomyoma and myometrium were measured in samples from 22 patients during either proliferative (n = 6) or secretory phases (n = 16) of the menstrual cycle. Relative amounts of collagenase (MMP-1) and stromelysin (MMP-3) mRNAs were measured by Northern blot analysis, and amounts of stromelysin 3 (MMP-11) and matrilysin (MMP-7) mRNA from each sample were determined by semiquantitative reverse transcriptase-polymerase chain reaction (RT-PCR) and normalized to beta-actin mRNA.

RESULTS

The levels of MMP-1 and MMP-3 mRNAs were similar in both leiomyoma and unaffected myometrium. The levels of MMP-11 mRNA were twofold greater in leiomyoma compared with myometrium throughout the menstrual cycle, and the differences in the levels of MMP-11 were significantly different during the secretory phase. The level of MMP-7 mRNA expression was similar in leiomyoma, myometrium, and endometrium.

CONCLUSIONS

Among the metalloproteinases examined in this study, only the levels of MMP-11 mRNA were elevated in leiomyoma compared with myometrium. The increased expression of MMP-11 in uterine leiomyoma compared with myometrium is analagous to previously reported elevations of MMP-11 mRNA in dermatofibromas compared with unaffected skin. The increased expression of MMP-11 mRNA in fibroid tumors suggests that this MMP may be involved in the formation of a more fibrous extracellular matrix in leiomyoma relative to unaffected myometrium.

Interferon-alpha is a potent inhibitor of basic fibroblast growth factor-stimulated cell proliferation in human uterine cells

PROBLEM

Abnormal uterine bleeding is a significant health problem for many women and is the number-one reason for performing hysterectomy in the United States. Leiomyomas (uterine fibroids) are benign neoplasms that are a frequent cause of abnormal uterine bleeding. The goal of this study was to assess the effects of the anti-angiogenic cytokine, interferon (INF)-alpha, on the proliferation of both leiomyoma and normal uterine cells.

METHOD OF STUDY

Primary cultures of leiomyoma, myometrial, and endometrial stromal cells were established for in vitro study. The effects of INF-alpha (10, 100, and 1000 U/ml) were tested on serum-stimulated and basic fibroblast growth factor-stimulated cell proliferation using the [3H]thymidine incorporation assay.

RESULTS

INF-alpha was a potent inhibitor of cell proliferation for all three cell types, with endometrial stromal cells showing the greatest sensitivity. The antiproliferative effect did not appear to result from toxic effects on the cells.

CONCLUSION

INFs may prove to be useful therapeutic agents for the treatment of leiomyoma-related abnormal uterine bleeding.

Pirfenidone: a novel pharmacological agent that inhibits leiomyoma cell proliferation and collagen production

There are currently no effective, long-term drug therapies for the treatment of leiomyomas. Pirfenidone (Marnac, Inc.) is an antifibrotic agent that is being tested for use in patients with pulmonary fibrosis. Because leiomyomas are characterized also by increased cell proliferation and tissue fibrosis, we examined the effects of pirfenidone on cell proliferation and collagen expression in cultured myometrial and leiomyoma smooth muscle cells. Effects of pirfenidone on proliferation of myometrial and leiomyoma cells were measured using tritiated thymidine incorporation assays and changes in actual cell numbers. Possible cytotoxic effects were examined using lactate dehydrogenase assays and trypan blue exclusion. Effects on collagen type I and type III production were assessed by Northern blotting. Doses of pirfenidone tested were: 0, 0.01, 0.1, 0.3, and 1.0 mg/mL. Serum-stimulated increases in DNA synthesis and cell proliferation by myometrial and leiomyoma cells were significantly inhibited in a dose-dependent manner by pirfenidone. Densitometric analysis of Northern blots showed significantly decreased expression of collagen type I and type III messenger RNAs in both leiomyoma and myometrial cells. Lactate dehydrogenase assays and trypan blue exclusion measurements showed no cytotoxic effect of pirfenidone at concentrations that inhibited cell proliferation and collagen production. Pirfenidone is an effective inhibitor of myometrial and leiomyoma cell proliferation in vitro and reduces the messenger RNA levels of collagen types I and III in a dose-dependent manner. This compound may prove to be an effective nonsteroidal therapy for treatment of uterine leiomyomas.

Leuprolide acetate-treated leiomyomas retain their relative overexpression of collagen type I and collagen type III messenger ribonucleic acid

OBJECTIVE

To evaluate the levels of mRNA for the extracellular matrix proteins collagen type I, collagen type III, and fibronectin in leiomyomas and myometrium obtained from women treated with GnRH-agonist (GnRH-a) and to examine steroid hormone regulation of these proteins using an in vitro explant culture system.

METHODS

Northern blot analysis of mRNA was obtained from hysterectomy specimens at the time of surgery or after 48 hours of in vitro steroid treatment. A portion of the tissue was processed for RNA, and the remaining tissue was used to establish explant cultures. Extracellular matrix/alpha-tubulin ratio was computed for each band, and within each experiment the lowest ratio was standardized to a value of one densitometry unit to allow for comparison among experiments.

RESULTS

There is a relative overexpression of both collagen type I and collagen type III mRNAs but not fibronectin in leiomyomas compared to myometrium from the same uteri of women treated with GnRH-a.

CONCLUSION

Leiomyomas obtained from women treated with GnRH-a show an up-regulation of collagens type I and type III similar to that seen in leiomyomas obtained from women in the proliferative phase of their menstrual cycles.

Expression of the fibroblast growth factor receptor in women with leiomyomas and abnormal uterine bleeding

Basic fibroblast growth factor (bFGF) is a regulator of angiogenesis which is overexpressed in leiomyomas compared with matched myometrium. To understand the physiological significance of this finding we characterized the expression of the type 1 receptor for this ligand (FGFR1). Utilizing reverse transcription-polymerase chain reaction (RT-PCR) we identified the complete and alternatively spliced transmembrane forms and two secreted forms of the FGFR1 in endometrium, myometrium and leiomyomas from all patients. This is the first report of secreted forms in uterine tissue. Proteins consistent with each of these isoforms were identified by Western blot analysis in all three tissues. Immunohistochemistry revealed menstrual cycle-specific regulation of FGFR1 protein in the endometrial stroma of normal women but not in women with leiomyomas and abnormal uterine bleeding. Stromal FGFR1 expression is suppressed in the early luteal phase in normal women, but not in women with leiomyoma-related bleeding. These findings support the role of the bFGF ligand-receptor system in the pathogenesis of leiomyoma-related bleeding and may have implications for fertility and contraception since the differential FGFR1 expression occurs in the peri-implantation period of the early luteal phase.

Leiomyoma-related bleeding: a classic hypothesis updated for the molecular era

Leiomyomas are an important cause of menorrhagia and other forms of abnormal uterine bleeding. The pathogenesis of this process is largely unknown, however. A classic theory, first suggested by Sampson's work in 1912 (Surg. Gynecol. Obstet., 14, 215-230), states that local dysregulation of the vascular structures in the uterus is responsible for this abnormal bleeding. Recent work demonstrates dysregulation of a number of growth factors in the myomatous uterus. As many of these factors regulate the process of angiogenesis or have other effects on vascular structures, we hypothesize that this dysregulation of growth factors or their receptors provides the molecular mechanism underlying these vascular abnormalities. In turn, these abnormal vessels lead women with leiomyomas to experience menorrhagia. Factors that may prove to be important in this process include basic fibroblast growth factor, vascular endothelial growth factor, heparin-binding epidermal growth factor, platelet-derived growth factor, transforming growth factor-beta, parathyroid hormone-related protein and prolactin. Current treatment regimens for women with leiomyoma-related bleeding depend on manipulation of the steroid hormone environment. By better understanding the pathogenesis of this disease process, therapies directed against growth factor abnormalities may result in better treatment with less harmful side-effects.

RU486 suppresses prolactin production in explant cultures of leiomyoma and myometrium

OBJECTIVE

To assess the action of RU486 (mifepristone), in the presence and absence of P, on PRL production by explant cultures of leiomyoma and myometrium.

DESIGN

Explant cultures using tissue from nine premenopausal women undergoing hysterectomy in the proliferative phase of the menstrual cycle; immunohistochemical staining of tissue sections from five patients for P receptor (PR) subtype.

MAIN OUTCOME MEASURES

Prolactin secretion (measured by RIA), lactate dehydrogenase secretion (measured by quantitative colorimetric assay), and immunohistochemistry for PR subtype.

RESULTS

Prolactin secretion was decreased in leiomyomas by RU486 at concentrations of 10(-7) M and 10(-5)M when normal serum-containing medium was used. In experiments with all detectable P removed from serum, PRL secretion was suppressed in both leiomyomas and myometrium at an RU486 concentration of 10(-7)M. Immunohistochemistry results suggest that the A form of the PR is the dominant form in both leiomyomas and myometrium.

CONCLUSIONS

Prolactin production is suppressed in both leiomyomas and myometrium after treatment with RU486 in vitro, and this suppression may serve as a marker for the clinical effectiveness of agents used in the treatment of leiomyomas.

The myometrium of postmenopausal women produces prolactin in response to human chorionic gonadotropin and alpha-subunit in vitro

OBJECTIVES

To examine the effect of equimolar concentrations of hCG and dissociated alpha-subunit on PRL production by leiomyoma and myometrial tissue obtained from different hormonal states and to examine changes in PRL messenger RNA levels as PRL protein levels increased.

DESIGN

Explant cultures of leiomyomas and myometrium were established and cultured for 96 hours. Tissue was studied from normal cycling women, postmenopausal women, pregnant women, and women undergoing GnRH agonist (GnRH-a) therapy. Cultured medium was collected at 24, 48, and 96 hours and assayed for PRL. In selected experiments, tissue was processed at 0 and 96 hours to analyze messenger RNA (mRNA) levels.

RESULTS

Human chorionic gonadotropin and alpha-subunit stimulated PRL secretion in [1] explant cultures of leiomyoma and myometrium from premenopausal women, [2] cultures of tissue treated in vivo with leuprolide acetate for both leiomyoma and myometrium, and [3] myometrium obtained from postmenopausal women. Postmenopausal myometrium was significantly more responsive to stimulation. Prolactin mRNA levels were documented to increase after hormone treatment in postmenopausal myometrium.

CONCLUSION

Myometrium from postmenopausal women is very responsive to hCG and alpha-subunit. There is a difference in response between tissue obtained from menopausal women and that from women undergoing GnRH-a therapy to achieve a "medical menopause" and reproductive age women. The level of endogenous gonadotropins as well as the steroid milieu may modulate myometrial PRL secretion.