Expression Of Growth Differentiation Factor Research Articles

P38 MAPK Contributes to Resistance and Invasiveness of HER2- Overexpressing Breast Cancer

Intrinsic or acquired resistance to the HER2-targeted therapy trastuzumab is a clinical concern in the treatment of patients with HER2-over-expressing metastatic breast cancers. We demonstrate here that multiple models of intrinsic and acquired resistance exhibit increased phosphorylation of p38 MAPK. Kinase inhibition of p38 rescued trastuzumab sensitivity in cells with acquired resistance. In addition, knockdown of p38 increased sensitivity to trastuzumab in an intrinsically resistant cell line. We previously reported that expression of growth differentiation factor 15 (GDF15) is increased in trastuzumab-resistant HER2-overexpressing breast cancer cells. In this study, we found that exogenous GDF15 or stable overexpression of GDF15 stimulated p38 phosphorylation in HER2-positive cells, suggesting a possible mechanism by which p38 is activated in resistant cells.GDF15 stable clones showed significantly increased invasiveness, which was rescued by p38 kinase inhibition, suggesting that p38 plays a role in the pro-invasive phenotype conferred by GDF15. Importantly, immunohistochemical analysis of a breast tumor tissue array indicated a significant (p=0.0053) correlation between HER2 and phosphorylated p38 specifically in GDF15-positive tissues. Our results suggest that p38 signaling drives trastuzumab resistance and invasiveness in HER2-overexpressing breast cancer. Upstream growth factor signals that have previously been implicated in trastuzumab resistance, such as GDF15, may contribute to the increased phosphorylation of p38 found in resistant cells.

The Evaluation of iron overload through hepcidin level and its related factors in myelodysplastic syndromes

We chose hepcidin and its related factors as evaluating indicators to determine the degrees of iron overload in myelodysplastic syndromes (MDS) patients. A total of 73 patients and 28 healthy volunteers were enrolled in this study. We performed enzyme-linked immunosorbent assay to measure both bone marrow and peripheral blood serum hepcidin. Real-time quantitative polymerase chain reaction was used to determine the gene expression of growth differentiation factor 15 and twisted gastrulation 1. Serum ferritin (SF), C-reactive protein (CRP), and erythropoietin were measured by routine standard laboratory assays. CD4+ and CD19+ lymphocytes and Th polarization were detected by flow cytometry. Twenty-four MDS patients were measured their cardiac and liver iron deposition levels through magnetic resonance imaging (MRI) T2* examination. No significant difference was found between the bone marrow hepcidin levels and peripheral blood hepcidin levels (P = 0.134). Stratified according to different World Health Organization subtypes, refractory anemia with ringed sideroblasts patients had the lowest hepcidin levels (105.40 ± 5.13 ng/ml), while refractory anemia with excess blasts-1 had the highest levels (335.71 ± 25.16 ng/ml). Stratified according to International Prognostic Scoring System and WHO Classification-based Prognostic Scoring System, there was a significant difference of hepcidin levels between low-risk group and high-risk group in two systems, respectively (P = 0.033 and 0.009). The hepcidin levels of CD4+ high-expression group were demonstrated higher than the normal expression groups (P = 0.02), but the CD19+ high-expression group did not show the same result (P = 0.206). Meanwhile, patients with a Th1 polarization trend had a high level of hepcidin versus normal group (P < 0.001). Liver iron concentration (LIC) measured by MRI T2* had a closer correlation (r = 0.582, P < 0.001) to hepcidin than serum ferritin, by stepwise regression. C-reactive protein and LIC seemed to be the key determinants of hepcidin, by multivariate regression. Inflammation plays an important role in the regulation of hepcidin expression. T-lymphocyte activation and Th polarization trend might participate in the regulatory mechanism partly. The capability of organ iron load assessment of MRI T2* seems better than that of SF. It seems that hepcidin with CRP and LIC measured by MRI T2* are potential indicators of iron overload in MDS patients.

Inhibitory effects of controlled ovarian stimulation on the expression of GDF9 and BMP15 in oocytes from women with PCOS

To explore the effects of controlled ovarian stimulation (COS) on the expression of growth differentiation factor 9 (GDF9) and bone morphogenetic protein 15 (BMP15) in oocytes and granulosa cells from patients with or without polycystic ovary syndrome (PCOS). This case-control study was conducted in the university affiliated hospital. The study comprised four groups of patients: eighteen PCOS patients with COS (stimulated-PCOS) and twenty-two PCOS patients without COS (unstimulated-PCOS), twenty-nine normal ovulatory women with COS (stimulated-control) and twenty-eight normal ovulatory women without COS (unstimulated-control). The oocytes and granulosa cells were collected and the abundance of GDF9 and BMP15 mRNA in the cells were detected by nested quantitative real-time PCR. The abundance of GDF9 and BMP15 mRNA was significantly higher both in oocytes (P < 0.01, P < 0.001, respectively) and GCs (P < 0.01, P < 0.05, respectively) from stimulated-control group than in unstimulated-control group. However, there was no significant difference for GDF9 or BMP15 mRNA in oocytes from stimulated-PCOS goup compared with unstimulated-PCOS group (P > 0.05, P > 0.05, respectively). The abundance of GDF9 mRNA was significantly lower (P < 0.01) while the abundance of BMP15 mRNA was significantly higher (P < 0.001) in GCs from stimulated-PCOS group than in unstimulated-PCOS group. The controlled ovarian stimulation can promote the expression of GDF9 and BMP15 both in oocytes and GCs from normal ovulatory women. However, the stimulating effects may be inhibited in oocytes from PCOS patients, which subsequently impair cytoplasm maturation and lead to poor oocyte quality.

Expression of growth differentiation factor 9 (GDF-9) during in vitro maturation in canine oocytes

The aim of this study was to characterize in canine oocytes and cumulus cells the dynamic expression of growth differentiation factor 9 (GDF-9) in relation to meiotic development and cumulus expansion throughout in vitro maturation (IVM). Cumulus oocytes complexes (COCs) from ovaries of adult bitches were cultured intact for IVM during 0, 48, 72, and 96 hours. At 0 hours or after IVM, COCs were divided into two groups: one group remained with their cumulus cells and in the other group the cumulus cells were extracted. The expression levels of GDF-9 were determined in both groups using indirect immunofluorescence and Western blot analysis. For immunofluorescence assay, in vivo-matured oocytes collected from oviducts were also used as a positive control. The nuclear stage was analyzed in parallel with 4′-6-diamidino-2-phenylindole staining in denuded oocytes from all maturing groups. The intensity of fluorescence, indicative of GDF-9 expression level, decreased with time (P < 0.05). High expression was observed only in germinal vesicle nonmature oocytes; in contrast, second metaphase oocytes showed only low expression. Western blot analysis showed bands of approximately 56 kd and a split band of approximately 20 kd representing the proprotein and possibly two mature protein forms of GDF-9, respectively. The proprotein was detected in all samples, and it was highly expressed before IVM and in a lesser degree, during the first 48 hours, declining thereafter in coincidence with the expansion of the cumulus cell (P < 0.05). There was a negative correlation (r = −0.97; P < 0.05) between the expression level of GDF-9 and mucification. Mature forms were evident only in COCs, before culture and up to 48 hours of IVM. It was concluded that GDF-9 is expressed in canine oocytes and cumulus cells, mainly in the early developmental states, with low levels in mature oocytes in vitro and in vivo, representing the first approach of GDF-9 dynamic in dog oocyte maturation.

Effect of superstimulatory treatments on the expression of genes related to ovulatory capacity, oocyte competence and embryo development in cattle

Multiple ovulation (superovulation) and embryo transfer has been used extensively in cattle. In the past decade, superstimulatory treatment protocols that synchronise follicle growth and ovulation, allowing for improved donor management and fixed-time AI (FTAI), have been developed for zebu (Bos indicus) and European (Bos taurus) breeds of cattle. There is evidence that additional stimulus with LH (through the administration of exogenous LH or equine chorionic gonadotrophin (eCG)) on the last day of the superstimulatory treatment protocol, called the 'P-36 protocol' for FTAI, can increase embryo yield compared with conventional protocols that are based on the detection of oestrus. However, inconsistent results with the use of hormones that stimulate LH receptors (LHR) have prompted further studies on the roles of LH and its receptors in ovulatory capacity (acquisition of LHR in granulosa cells), oocyte competence and embryo quality in superstimulated cattle. Recent experiments have shown that superstimulation with FSH increases mRNA expression of LHR and angiotensin AT(2) receptors in granulosa cells of follicles >8 mm in diameter. In addition, FSH decreases mRNA expression of growth differentiation factor 9 (GDF9) and bone morphogenetic protein 15 (BMP15) in oocytes, but increases the expression of both in cumulus cells, without diminishing the capacity of cumulus-oocyte complexes to generate blastocysts. Although these results indicate that superstimulation with FSH is not detrimental to oocyte competence, supplementary studies are warranted to investigate the effects of superstimulation on embryo quality and viability. In addition, experiments comparing the cellular and/or molecular effects of adding eCG to the P-36 treatment protocol are being conducted to elucidate the effects of superstimulatory protocols on the yield of viable embryos.

Modulation of Activin Signaling by RAP-011 (ActRIIA-IgG1) Improve Anemia, Increases Hemoglobin Levels and Corrects Ineffective Erythropoiesis in β-Thalassemia

AbstractAbstract 247 Background:β-thalassemia is associated with ineffective erythropoiesis, accelerated erythroid differentiation and apoptosis resulting in anemia and iron overload. The molecular mechanism involved is still incompletely understood. Members of the TGF-β superfamily participate in both proliferation and differentiation of erythroid progenitors. However, the role of these molecules in models of ineffective erythropoiesis has not been addressed so far. RAP-011 is a ligand trap consisting of the extracellular domain of ActRIIA linked to mouse IgG1 Fc domain. We aimed to study the role of ActRIIA signaling in the ineffective erythropoiesis of β-thalassemia and to evaluate the therapeutic impact of RAP-011. Methods:Hbbth1/th1 mice (a model of β-thalassemia intermedia) were subcutaneously treated with RAP-011 (10mg/kg body weight) twice a week for 30–60 days and biological and biochemical parameters were followed. Results:RAP-011 treatment significantly increased hemoglobin levels, red blood cell counts, MCV, MCH and hematocrit with a concomitant decrease in bilirubin levels and reticulocyte counts (since 10 days of treatment and sustained until day 60 of follow up). Flow cytometry analysis showed that RAP-011 significantly decreased late basophilic and polychromatic erythroblast cell numbers in both bone marrow and spleen indicating that RAP-011 corrects ineffective erythropoiesis. We next evaluated the expression of putative ActRIIA ligand(s) in β-thalassemia. Increased expression of Growth Differentiation Factor 11 (GDF11) was observed in cultured erythroblasts and in spleen sections of thalassemic mice. RAP-011 treatment decreased these elevated GDF11 levels in both bone marrow and spleen. We further investigated how BMP/Activin signaling was involved in ineffective erythropoiesis. Anti-GDF11 antibodies, follistatin (activin and GDF11 antagonist) and dorsomorphin (a small molecule inhibitor of SMAD1/5/8 phosphorylation) reduced differentiation, induced FAS-L expression and apoptosis in erythroblasts both in vivo and in vitro whereas noggin (a BMP-2/4 antagonist) had no effect on erythroblast differentiation. Altogether, these data suggest that Activin/BMP signaling controls erythroblast differentiation and targeting BMP type II /activin type II receptors can decrease ineffective erythropoiesis of β-thalassemia. Summary:Sotatercept (a humanized version of RAP-011) is currently in phase II clinical trials for treatment of anemia in patients with Myeloma Bone Disease and End Stage Renal Disease and data from our non-clinical findings support a newly initiated β-thalassemia clinical trial. Our results suggest that sotatercept would be a potential therapeutic tool to improve anemia, increase hemoglobin levels and correct ineffective erythropoiesis and its side effects in β-thalassemic patients. Disclosures:Daniel:Celgene Corporation: Employment. Chopra:Celgene Corp: Employment, Equity Ownership. Sung:Celgene: Employment.

Study on ovary development in vitrification of embryos born mice and expression of growth differentiation factor 9

To study ovarian development in vitrification of embryos born mice and expression of growth differentiation factor 9 (GDF-9) in its. The vitrification recovery embryos (vitrified-embryo group) and fresh embryos (fresh-embryo group) were transplanted into pseudopregnant mice, respectively. The female offspring mice in two groups were sacrificed on the 3(rd), 7(th), 14(th), 21(st), 28(th) and 60(th) day after birth, the ovarian tissues were taken, 6 mice in each time point of each group. The ovarian development was observed by HE staining, the expression of GDF-9 mRNA and protein at each time point of two groups were detected by reverse transcription (RT)-PCR and western blot. HE staining showed that no abnormal ovarian development was observed in offsprings at two groups. On the 3(rd), 7(th), 14(th), 21(st), 28(th) and 60(th) day after birth, the expression of GDF-9 mRNA in vitrified-embryo group were 0.14 ± 0.07, 0.42 ± 0.16, 1.00 ± 0.24, 1.59 ± 0.28, 2.05 ± 0.32 and 2.23 ± 0.21, respectively, which in fresh-embryo group were 0.13 ± 0.06, 0.45 ± 0.18, 1.00 ± 0.21, 1.56 ± 0.26, 2.01 ± 0.37 and 2.26 ± 0.23, respectively, there was no statistical difference between two groups (P > 0.05); the expression of GDF-9 protein in vitrified-embryo group were 0.040 ± 0.030, 0.120 ± 0.060, 0.170 ± 0.030, 0.250 ± 0.040, 0.320 ± 0.060 and 0.330 ± 0.010, respectively, which in fresh-embryo group were 0.030 ± 0.020, 0.110 ± 0.040, 0.150 ± 0.010, 0.210 ± 0.020, 0.360 ± 0.070 and 0.350 ± 0.030, respectively, there was no statistical difference between two groups (P > 0.05). The ovarian morphology in vitrification of embryos born mice and expression of GDF-9 in ovary has no any obvious change.

Expression of growth differentiation factor 9 (GDF9), ALK5, and claudin-11 in adult alpaca testis

Growth differentiation factor 9 (GDF9) is an oocyte-derived factor critical for folliculogenesis. Recently, in vitro data showed that GDF9 inhibited the localization of tight junction (TJ) proteins, suggesting that GDF9 could potentially regulate spermatogenesis in vivo, via inhibition of Sertoli cell TJ function. The purpose of the present study was to determine the expression and localization of GDF9, its receptor, ALK5, and its latent target protein, claudin-11 (one of TJ proteins) in adult alpaca testis using Western blot and immunohistochemistry. Western blotting results demonstrated that GDF9, ALK5 and claudin-11 were expressed in the adult alpaca testis. Immunohistochemistry revealed that GDF9 was expressed stage-specifically in the cytoplasm of pachytene spermatocytes and round spermatids of the adult alpaca seminiferous epithelium. Type I receptor, ALK5 was mainly localized in the cytoplasm of round spermatids and Leydig cells, and to a lesser extent in the cytoplasm of pachytene spermatocytes and Sertoli cells. Its latent target protein, claudin-11, was perpendicular or parallel to the basal lamina in the basal part of Sertoli cells. These results indicated that GDF9, as a paracrine and autocrine growth factor derived from round spermatids and pachytene spermatocytes, is involved in regulating spermatogenesis via action on germ cells or somatic cells (i.e. Leydig cells, Sertoli cells).

Androstenedione induces abnormalities in morphology and function of developing oocytes, which impairs oocyte meiotic competence

To obtain insight into the effects of androstenedione on ovarian folliculogenesis and oogenesis. Experimental study. St. Marianna University School of Medicine. Prepubertal (14-day-old) BDF1 female mice. Early secondary follicles were isolated from the ovaries and were cultured individually in vitro with or without androstenedione (10(-11) to 10(-5) M) for 12 days. Thereafter, the follicles were treated with hCG and epidermal growth factor (EGF). Diameters and morphology of follicles and oocytes; E(2) and P secretion; and chromatin configuration and expression of growth differentiation factor 9 (GDF9) in oocytes were examined. Early secondary follicles developed to the preovulatory stage. Androstenedione treatments increased the follicle diameters, reduced survival rates of follicles, and promoted the formation of follicles with abnormal morphology, including misshapen oocyte. The secretion of E(2) and P was significantly higher in androstenedione-exposed follicles. Androstenedione prevented the alteration in chromatin configuration and reduced oocyte GDF9 expression. When follicles cultured with androstenedione were treated with hCG and EGF, the first polar body exclusion, chromosome alignment on metaphase plate, and spindle assembly were inhibited in the oocytes. These results demonstrate that excess androgen induces abnormalities in the morphology and function of developing oocytes, which impairs oocyte meiotic competence.

Abnormal expression of growth differentiation factor 9 (GDF9) and bone morphogenetic protein 15 (BMP15) in ovarian tissues from unstimulated polycystic ovaries

This study was designed to investigate the expression of GDF9 and BMP15 in ovarian tissues from unstimulated ovaries of women with PCOS, and explore whether they are associated with aberrant folliculogenesis in PCOS.

Abnormal expression of growth differentiation factor 9 and bone morphogenetic protein 15 in stimulated oocytes during maturation from women with polycystic ovary syndrome

To investigate the expression pattern of two oocyte-secreted factors-growth differentiation factor 9 (GDF9) and bone morphogenetic protein 15 (BM15)-during oocyte maturation in women with polycystic ovary syndrome (PCOS) and in controls and to evaluate the expression differences in oocytes between the two groups. Case-control study. University-affiliated hospital. Twenty-five oocytes were obtained from 12 patients with PCOS and 82 oocytes from 56 controls. None. The abundance of GDF9 and BMP15 mRNA in oocytes of the germinal vesicle (GV), metaphase I (MI), and MII stage. The expression of GDF9 and BMP15 mRNA displayed dynamic changes during oocyte maturation in controls after ovarian stimulation, with a decline at the MI stage and an increase to the peak at the MII stage. However, their expression in oocytes from patients with PCOS demonstrated a reduced state without any dynamic change. The results suggest that the expression of GDF9 and BMP15 in oocytes from patients with PCOS cannot reach the normal level even after ovarian stimulation and that the expression pattern is abnormal during oocyte maturation, which may be associated with impaired oocyte quality and developmental competence in PCOS.

Expression of growth differentiation factor 9 (GDF9) and its receptor in adult cat testis

Oocyte-secreted growth differentiation factor (GDF) 9 plays an essential role during follicle maturation through actions on granulosa cells. Despite its critical role in female reproduction, GDF9 expression, signalling and function are less well characterized during spermatogenesis. The purpose of this study was to investigate temporal and spatial expression and potential cellular targets of GDF9 in the adult cat testis. Our result confirmed that GDF9 is stage-specifically localized in the cytoplasm of round spermatids and pachytene spermatocytes of the cat seminiferous epithelium. In particular, activin receptor-like kinase (ALK) 5, the type I receptor of GDF9, is principally localized in the cytoplasm of round spermatids. Smad2/3, signal transducers for GDF9 signalling pathway, is mainly immunolocalized in the cytoplasm of germ cells, Sertoli cells and Leydig cells, but the expression in germ cells are weaker than in Sertoli cells. The expression pattern of ALK5 and Smad2/3 show that GDF9-ALK5-Smad2/3 may not be the only signalling pathway for testicular cell to respond to GDF9. Overall, our results demonstrate that GDF9 is a germ cell-specific factor in the adult cat testis, and that GDF9 regulates the tight junctions of Sertoli cells by paracrine secretion, and regulates the germ cells by autocrine secretion.

Expression of growth differentiation factor 9 (GDF9) and bone morphogenetic protein 15 (BMP15) in the oocytes from unstimulated polycystic ovaries

OBJECTIVE: This study was designed to investigate the expression of GDF9 and BMP15 mRNA in the oocytes from unstimulated ovaries of women with PCOS, and explore whether they are associated with aberrant folliculogenesis in PCOS.

Expression of growth differentiation factor 15 is not elevated in individuals with iron deficiency secondary to volunteer blood donation

Low serum hepcidin levels provide a physiologic response to iron demand in patients with iron deficiency (ID). Based on a discovery of suppressed hepcidin expression by a cytokine named growth differentiation factor 15 (GDF15), it was hypothesized that GDF15 may suppress hepcidin expression in humans with ID due to blood loss. To test this hypothesis, GDF15 and hepcidin levels were measured in peripheral blood from subjects with iron-deficient erythropoiesis before and after iron supplementation. Iron variables and hepcidin levels were significantly suppressed in iron-deficient blood donors compared to healthy volunteers. However, ID was not associated with elevated serum levels of GDF15. Instead, iron-deficient subjects' GDF15 levels were slightly lower than those measured in the control group of subjects (307 +/- 90 and 386 +/- 104 pg/mL, respectively). Additionally, GDF15 levels were not significantly altered by iron repletion. ID due to blood loss is not associated with a significant change in serum levels of GDF15.

Growth differentiation factor-15 as a prognostic biomarker in ovarian cancer

Objectives There is a need for identification of new biomarkers improving our understanding, diagnosis, and follow-up of ovarian cancer. Growth differentiation factor-15 (GDF-15) is a member of the transforming growth factor-β superfamily, and GDF-15 overexpression has been found in several cancer forms but has not been explored in ovarian cancer. The aim of the study was to explore preoperative plasma concentration and tissue expression of growth differentiation factor (GDF)-15 in ovarian tumors. Methods GDF-15 concentration was measured by immunoradiometric assay in plasma samples from patients with invasive ovarian cancer ( n = 125), borderline ovarian tumor (BOT, n = 43), and benign ovarian tumor ( n = 144), from healthy women ( n = 40), as well as in effusion samples ( n = 44) from women with advanced ovarian cancer. Sections of ovarian carcinoma ( n = 20), BOT ( n = 9), and cystadenoma ( n = 7) were immunostained for GDF-15. Results Median plasma GDF-15 concentration was elevated in ovarian cancer as compared to healthy controls and women with benign ovarian tumors or BOT ( p < 0.001). GDF-15 plasma concentration correlated inversely with survival time and was an independent predictor of survival, after correction for FIGO stage and age ( p = 0.01). GDF-15 protein was cytoplasmatically expressed in serous tumor cells and detectable in high concentrations in effusion samples. Conclusion GDF-15 emerges as a new potential biomarker in ovarian cancer.

Expression of growth differentiation factor 15 is positively correlated with histopathological malignant grade and in vitro cell proliferation in oral squamous cell carcinoma

Previously, we established an in vitro cellular carcinogenesis model of oral squamous cell carcinoma (OSCC) and expression microarray analysis showed that the gene encoding growth differentiation factor 15 (GDF15) was significantly upregulated in this model. In this study, we confirmed that expression of GDF15 was increased both at mRNA and protein levels in a panel of OSCC lines and clinical samples from primary OSCC patients. We also observed that expression of GDF15 was positively correlated with the malignancy of the disease: a higher level of GDF15 expression indicates a higher malignant grade of OSCC. Treatment of OSCC cell line (Tca3118) with siRNA against GDF15 significantly inhibited cellular proliferation and colony formation. Based on these observations, we conclude that GDF15 is a positive gene of OSCC development and progression and GDF15 can be used as an additional marker for histopathologic evaluation of OSCC differentiation.

Expression of growth differentiation factor 9, bone morphogenetic protein 15, and anti-Müllerian hormone in cultured mouse primary follicles

Growth differentiation factor 9 (GDF9), bone morphogenetic protein 15 (BMP15), and anti-Müllerian hormone (AMH) play an important role in the primary to secondary follicle transition and follicle activation in vivo. In organ culture of neonatal mouse ovaries, it was observed that significantly fewer primary follicles develop to the secondary stage. The objectives of this study were: (1) to compare ovarian follicular populations between organ-cultured neonatal mouse ovaries and freshly isolated age-matched control ovaries; (2) to quantify RNA levels of Gdf9, Bmp15, and Amh in cultured primary follicles; and (3) to immunolocalize GDF9 and AMH in cultured ovaries. Ovaries from 3-day-old (PND 3) mice were cultured for 7 or 10 days in the absence or presence of FSH. Follicular populations were counted in freshly isolated 13-day-old (PND 13) ovaries and organ-cultured ovaries. Transcripts were quantified in isolated primary follicles using real-time RT-PCR, and protein expressions were localized using immunohistochemistry. The number of secondary follicles in organ-cultured ovaries was significantly lower than in vivo controls. Gdf9 and Bmp15 mRNA expression levels were similar as in controls. Amh mRNA levels were significantly (P<0.05) lower after day 10 of culture in the absence of FSH. GDF9 and AMH proteins were respectively detected in the oocytes and the granulosa cells (GC) beginning at the primary and primordial stages onward. GDF9 and BMP15 production in cultured primary follicles are not different from in vivo controls; hence abnormal early follicular growth was not related to a deficient transcription of these factors.

Differentially regulated expression of growth differentiation factor 5 and bone morphogenetic protein 7 in articular cartilage and synovium in murine chronic arthritis: Potential importance for cartilage breakdown and synovial hypertrophy

To examine whether the endogenous expression of growth differentiation factor 5 (GDF-5) and bone morphogenetic protein 7 (BMP-7) is altered in the cartilage and synovium of human tumor necrosis factor alpha (TNFalpha)-transgenic (hTNFtg) mice with chronic arthritis, and to investigate the response of hTNFtg chondrocytes as well as fibroblast-like synoviocytes (FLS) to these morphogens in vitro. Analyses were performed in hTNFtg mice with chronic destructive arthritis and in wild-type (WT) mice as controls. Expression of GDF-5 and BMP-7 in the articular cartilage and synovium was examined by real-time polymerase chain reaction and immunohistochemistry. Human TNFtg cartilage explants, chondrocytes, and FLS monolayer cultures were assessed for basal matrix biosynthesis as well as growth factor responsiveness, using (35)S-sulfate incorporation assays. In addition, the DNA content/cell proliferation rate was measured. The expression of GDF-5 and BMP-7 was decreased in articular cartilage from hTNFtg mice, whereas expression of both morphogens was increased in arthritic synovium from hTNFtg mice, as compared with the levels in WT controls. Isotope incorporation revealed a marked reduction of matrix synthesis in hTNFtg cartilage as well as a decrease in responsiveness to GDF-5 and BMP-7. The DNA content did not change in arthritic cartilage as compared with WT cartilage. In hTNFtg FLS, growth factor stimulation increased the rate of cell proliferation and the production of extracellular matrix. In this murine model of TNFalpha-mediated arthritis, the expression of GDF-5 and BMP-7 is regulated differentially in articular cartilage and synovium. In articular cartilage, the down-regulation of GDF-5 and BMP-7, which function to maintain matrix integrity, could potentially compromise tissue repair, whereas in synovium, the increased expression of GDF-5 and BMP-7 might contribute to synovial hypertrophy.

Dynamics of expression of growth differentiation factor 15 in normal and PIN development in the mouse

Growth differentiation factor (GDF15) is a distant member of the transforming growth factor-β superfamily, a diverse group of structurally related proteins that exert multiple effects on cell fate such as on cell growth and differentiation but little is known about GDF15 in these processes. Previously we observed the mature GDF15 to be associated with human prostate carcinogenesis hence prompting us to study GDF15 further. Here we report gdf15 expression both at the RNA and protein levels, in normal prostatic tissues of wild type (wt) and prostatic intraepithelial neoplasia (PIN) of transgenic (Tg) 12T-7s model mice during embryonic, postnatal, and adult prostate formation up to 15 weeks after birth. Dynamic changes in expression, at both the mRNA and protein level, correlated with cell proliferation and differentiation during distinct phases of normal mouse prostate development and alterations in the dynamics of gdf15 expression correlated with the changes in development resulting in PIN formation. Most notably mature gdf15 protein was significantly elevated during hyperplasia and PIN development. Changes in the protein levels did not always correlate well with the mRNA levels. This was more prominent during PIN than during normal prostate development suggesting that this may also be an indicator of disturbed regulation of gdf15 in PIN. We propose that gdf15 is a growth factor with dual function either promoting proliferation or growth arrest and differentiation due most likely to differences in cellular differentiation. Because of the differentiation defect in PIN its epithelium no longer responds to gdf15 by cellular growth arrest as does the normal epithelium and gdf may even stimulate proliferation. The data supports our hypothesis that GDF15 plays a role in the early stages of human prostate cancer.

Erythropoietin Modulation of Podocalyxin within an Erythroblast Niche.

Epo's capacity to promote red cell production is ascribed largely to anti-apoptotic effects on erythroid progenitor pools. Via gene profiling of bone marrow- derived erythroblasts, Epo is now revealed to down-modulate chemokine receptor-4 (Cxcr4) and integrin alpha-4 (Itga4), and to selectively up-modulate the expression of growth differentiation factor 3 (Gdf3), oncostatin-M (Onco-M), and the sialomucin podocalyxin like-1 (PODXL). Epo dose-dependent induction of PODXL was approximately 20 fold; was discovered in KitposCD71high erythroblasts; and peaked at subsequent KitnegCD71high and Ter119pos stages. As studied using minimal knocked-in Epo receptor (EpoR) alleles, efficient PODXL expression depended upon a proximal EpoR PY343 Stat5 binding site. In mice expressing a phosphotyrosine-null EpoR-HM allele, compromised PODXL expression further correlated with an abnormal representation of anucleated red cells in marrow (and with defective Epo-induced production of PODXLpos reticulocytes). By selectively modulating Gdf3, Onco-M, Cxcr4, Itga-4 and PODXL expression, Epo is proposed to modify a unique erythroid niche, mobilize early-stage erythroblasts, and promote reticulocyte emigration to blood.