Heregulin Activity Assays for Residual Testing of Cell Therapy Products.

BACKGROUND: Heregulin is a ligand for the protooncogene product ErbB/HER that acts as  a key mitogenic factor for human Schwann cells (hSCs). Heregulin is required for sustained hSC growth in vitro but must be thoroughly removed before cell collection for transplantation due to potential safety concerns. The goal of this study was to develop simple cell-based assays to assess the effectiveness of heregulin addition to and removal from aliquots of hSC culture medium. These bioassays were based on the capacity of a ß1-heregulin peptide to elicit ErbB/HER receptor signaling in adherent ErbB2+/ErbB3+ cells. RESULTS: Western blotting was used to measure the activity of three different ß1-heregulin/ErbB-activated kinases (ErbB3/HER3, ERK/MAPK and Akt/PKB) using phospho-specific antibodies against key activating residues. The duration, dose-dependency and specificity of ß1-heregulin-initiated kinase phosphorylation were investigated, and controls were implemented for assay optimization and reproducibility to detect ß1-heregulin activity in the nanomolar range. Results from these assays showed that the culture medium from transplantable hSCs elicited no detectable activation of the aforementioned kinases in independent rounds of testing, indicating that the implemented measures can ensure that the final hSC product is devoid of bioactive ß1-heregulin molecules prior to transplantation. CONCLUSIONS: These assays may be valuable to detect impurities such as undefined soluble factors or factors for which other biochemical or biological assays are not yet available. Our workflow can be modified as necessary to determine the presence of ErbB/HER, ERK, and Akt activators other than ß1-heregulin using native samples, such as fresh isolates from cell- or tissue extracts in addition to culture medium.

Schwann cell dedifferentiation is independent of mitogenic signaling and uncoupled to proliferation: role of cAMP and JNK in the maintenance of the differentiated state.

Myelinating Schwann cells (SCs) are highly plastic cells that are able to dedifferentiate and re-enter the cell cycle. However, the molecular signals controlling dedifferentiation are not completely understood. Because a connection between mitogenic signaling and myelin loss has been suggested, we investigated the role of cAMP, a strong inducer of the myelinating phenotype, and mitogenic factors activating receptor tyrosine kinases (RTKs) on SC dedifferentiation. We herein provide evidence indicating that cAMP was required to not only initiate but also maintain a state of differentiation because SCs rapidly dedifferentiated and became competent to resume proliferation upon the removal of cAMP stimulation. Surprisingly, isolated SCs could undergo multiple cycles of differentiation and dedifferentiation upon cAMP addition and removal, respectively, in the absence of mitogenic factors and without entering the cell cycle. Conversely, the activation of RTKs and the ERK cascade by a variety of growth factors, including neuregulin, was not sufficient to initiate dedifferentiation in the presence of cAMP. Importantly, a reduction of cAMP triggered dedifferentiation through a mechanism that required JNK, rather than ERK, activity and an induction of the expression of c-Jun, a transcriptional inhibitor of myelination. In summary, the reversible transition from an undifferentiated to a myelinating state was dependent on cAMP but independent of RTK signaling and cell cycle progression, further indicating that dedifferentiation and proliferation are uncoupled and differentially regulated events in SCs.

A Phase II study of autologous mesenchymal stromal cells and c-kit positive cardiac cells, alone or in combination, in patients with ischaemic heart failure: the CCTRN CONCERT-HF trial.

AIMS: CONCERT-HF is an NHLBI-sponsored, double-blind, placebo-controlled, Phase II trial designed to determine whether treatment with autologous bone marrow-derived mesenchymal stromal cells (MSCs) and c-kit positive cardiac cells (CPCs), given alone or in combination, is feasible, safe, and beneficial in patients with heart failure (HF) caused by ischaemic cardiomyopathy. METHODS AND RESULTS: Patients were randomized (1:1:1:1) to transendocardial injection of MSCs combined with CPCs, MSCs alone, CPCs alone, or placebo, and followed for 12 months. Seven centres enrolled 125 participants with left ventricular ejection fraction of 28.6 ± 6.1% and scar size 19.4 ± 5.8%, in New York Heart Association class II or III. The proportion of major adverse cardiac events (MACE) was significantly decreased by CPCs alone (-22% vs. placebo, P = 0.043). Quality of life (Minnesota Living with Heart Failure Questionnaire score) was significantly improved by MSCs alone (P = 0.050) and MSCs + CPCs (P = 0.023) vs. placebo. Left ventricular ejection fraction, left ventricular volumes, scar size, 6-min walking distance, and peak oxygen consumption did not differ significantly among groups. CONCLUSIONS: This is the first multicentre trial assessing CPCs and a combination of two cell types from different tissues in HF patients. The results show that treatment is safe and feasible. Even with maximal guideline-directed therapy, both CPCs and MSCs were associated with improved clinical outcomes (MACE and quality of life, respectively) in ischaemic HF without affecting left ventricular function or structure, suggesting possible systemic or paracrine cellular mechanisms. Combining MSCs with CPCs was associated with improvement in both these outcomes. These results suggest potential important beneficial effects of CPCs and MSCs and support further investigation in HF patients.

Activities of steroid metabolic enzymes in secretory endometria from untreated women with Polycystic Ovary Syndrome.

Polycystic Ovary Syndrome (PCOS) is an endocrine-metabolic pathology related with infertility and recurrent miscarriage. We have previously shown that the endometrium of these patients can exhibit a potentially higher sensitivity to estrogen action, being estrogens important regulators of the cell cycle and tissue homeostasis. The effect of estrogens on tissues depends on their in situ availability, which is in part regulated by the activity of steroid metabolic enzymes within the tissues. Therefore, the objective of the present study was to analyze if the activity and/or expression of steroid metabolic enzymes in endometria from women with PCOS differ from controls. For this purpose, the activity of the enzymes was determined by using radiometric assays and the mRNA levels measured by semi-quantitative RT-PCR. Both assays were assessed in endometria obtained during mid secretory phase from control (CE, n=12) and PCOS women (PCOSE, n=11). For the statistical analyses, Mann-Whitney and Student's t-tests were used to compare CE and PCOSE, considering a p value <0.05 significantly different. The results showed an increase in the sulfatase activity in PCOS respect to control endometria (200+/-28pmol/mg vs. 115+/-13pmol/mgproth; p<0.05), in agreement with the higher mRNA levels found for the enzyme in PCOSE. In addition, a PCOSE exhibited lower activity of sulfotransferase respect to the control group (50+/-21pmol/mg vs. 124+/-10pmol/mgproth; p<0.05), whereas a higher level of 17beta-hydroxysteroid dehydrogenase type 1mRNA was found in PCOSE compared with the control tissues (p<0.05). The activity of 17beta-hydroxysteroid dehydrogenase type 2 and the mRNA levels of sulfotransferase were similar in both groups; meanwhile, the expression of aromatase was undetectable. These data indicate that the sulfatase pathway could play an important role in the local production of estrogens in PCOSE from secretory phase. This potentially higher bioavailability of estrogens in endometria from PCOS women could influence the deregulation of tissue homeostasis that we have previously reported, and could partially explain the poor reproductive performance observed in this group of patients.

Augmented cell survival in eutopic endometrium from women with endometriosis: expression of c-myc, TGF-beta1 and bax genes.

BACKGROUND: Endometriosis is a common gynaecological disorder characterized by the presence of endometrial tissue outside of the uterus. The fragments in normal menstruation are composed of necrotic and living cells, which do not survive in ectopic locations because of programmed cell death. The aim of this study was to evaluate if the balance between cell proliferation and apoptosis is changed in eutopic endometrium from women with endometriosis throughout the menstrual cycle by studying bax (pro-apoptotic), c-myc (regulator of cell cycle) and TGF-beta1 (involved in cell differentiation) genes. METHODS: Eutopic endometrium was obtained from: 30 women with endometriosis (32.8 +/- 5 years) and 34 fertile eumenorrheic women (36 +/- 5.3 years). We analyzed apoptosis (TUNEL: DNA fragmentation); cell proliferation (immunohistochemistry (IHC) for Ki67); c-myc, bax and TGF-beta1 mRNA abundance (RT-PCR) and TGF-beta1 protein (IHC) in endometrial explants. RESULTS: Cell proliferation strongly decreased from proliferative to late secretory phases in glands, but not in stroma, in both endometria. Positive staining in glands and stroma from proliferative endometrium with endometriosis was 1.9- and 2.2-fold higher than control endometrium, respectively (p < 0.05). Abundance of c-myc mRNA was 65% higher in proliferative endometrium from endometriosis than normal tissue (p < 0.05). TGF-beta1 (mRNA and protein) augmented during mid secretory phase in normal endometrium, effect not observed in endometrium with endometriosis. In normal endometrium, the percentage of apoptotic epithelial and stromal cells increased more than 30-fold during late secretory phase. In contrast, in endometrium from endometriosis, not only this increase was not observed, besides bax mRNA decreased 63% versus normal endometrium (p < 0.05). At once, in early secretory phase, apoptotic stromal cells increased 10-fold with a concomitant augment of bax mRNA abundance (42%) in endometria from endometriosis (p < 0.05). CONCLUSION: An altered expression of c-myc, TGF-beta1 and bax was observed in eutopic endometrium from endometriosis, suggesting its participation in the regulation of cell survival in this disease. The augmented cell viability in eutopic endometrium from these patients as a consequence of a reduction in cell death by apoptosis, and also an increase in cell proliferation indicates that this condition may facilitate the invasive feature of the endometrium.

Requirement of cAMP signaling for Schwann cell differentiation restricts the onset of myelination.

Isolated Schwann cells (SCs) respond to cAMP elevation by adopting a differentiated post-mitotic state that exhibits high levels of Krox-20, a transcriptional enhancer of myelination, and mature SC markers such as the myelin lipid galactocerebroside (O1). To address how cAMP controls myelination, we performed a series of cell culture experiments which compared the differentiating responses of isolated and axon-related SCs to cAMP analogs and ascorbate, a known inducer of axon ensheathment, basal lamina formation and myelination. In axon-related SCs, cAMP induced the expression of Krox-20 and O1 without a concomitant increase in the expression of myelin basic protein (MBP) and without promoting axon ensheathment, collagen synthesis or basal lamina assembly. When cAMP was provided together with ascorbate, a dramatic enhancement of MBP expression occurred, indicating that cAMP primes SCs to form myelin only under conditions supportive of basal lamina formation. Experiments using a combination of cell permeable cAMP analogs and type-selective adenylyl cyclase (AC) agonists and antagonists revealed that selective transmembrane AC (tmAC) activation with forskolin was not sufficient for full SC differentiation and that the attainment of an O1 positive state also relied on the activity of the soluble AC (sAC), a bicarbonate sensor that is insensitive to forskolin and GPCR activation. Pharmacological and immunological evidence indicated that SCs expressed sAC and that sAC activity was required for morphological differentiation and the expression of myelin markers such as O1 and protein zero. To conclude, our data indicates that cAMP did not directly drive myelination but rather the transition into an O1 positive state, which is perhaps the most critical cAMP-dependent rate limiting step for the onset of myelination. The temporally restricted role of cAMP in inducing differentiation independently of basal lamina formation provides a clear example of the uncoupling of signals controlling differentiation and myelination in SCs.

Potential action of androstenedione on the proliferation and apoptosis of stromal endometrial cells.

BACKGROUND: Hyperandrogenic conditions have been associated with a high prevalence of endometrial pathologies related to cell survival. However, the action of androgens on proliferation and apoptosis in endometrial cells is poorly understood. Therefore, the aim of the present study was to evaluate the effect of androstenedione on cell proliferation, cell death and expression of estrogen receptor (ER) isoforms and proteins related to apoptosis in endometrial cells using two in vitro experimental approaches. METHODS: The endometrial tissue was obtained from 20 eumenorrheic women [28.7 (25 - 35) years] during the early secretory phase. We analyzed cell proliferation (immunohistochemistry of Ki-67 and spectrophotometric assay); apoptosis (DNA fragmentation (TUNEL) and Annexin V-FITC binding); ER-alpha, ER-beta bcl-2 and bax mRNA abundance (RT-PCR) in explants and isolated endometrial epithelial (EEC) and stromal cells (ESC) incubated with androstenedione 1 micro mol/l (A4) or A4 plus hydroxyflutamide 10 micro mol/l (F) for 24 h. RESULTS: In explants, A4 induced an increase of cell proliferation and a decrease on apoptosis in the stromal compartment (p < 0.05). In isolated ESC, proliferation augmented with A4 (p < 0.05), whereas, no significant modifications in the expression of ER-alpha, ER-beta bcl-2 and bax nor in the apoptotic index were observed. In EEC, A4 increase the ER-beta mRNA abundance (p < 0.05) and a decrease of the bcl-2/bax ratio (p < 0.05), without an increase in the apoptotic index. Hydroxyflutamide reverted the effect of androstenedione on the parameters described. CONCLUSIONS: These results indicate that androstenedione may modulate cell survival, expression of ER-beta and proteins related to apoptosis, suggesting a potential mechanism that associates the effect of hyperandrogenemia on the endometrial tissue.

Hormonal profile and androgen receptor study in prepubertal girls with hypertrichosis.

BACKGROUND: Prepubertal hypertrichosis is a reportedly benign condition characterized by an excessive growth of vellous hair in non-androgen dependent areas of the body compared to the amount usually present in normal subjects of the same age, race and sex. Although this condition is usually considered idiopathic and regarded as benign, it may be very disturbing cosmetically, causing significant patient and parental anxiety. METHOD: We performed a hormonal and androgen receptor study in 42 prepubertal girls with hypertrichosis and 29 control girls from 2 to 8 years of age. Both groups underwent a determination of basal LH, FSH, 17OH progesterone, androstenedione, testosterone, estradiol and SHBG, abdominal ultrasound to assess ovarian morphology, and the number of androgen receptor CAG/GGC repeats in DNA obtained from peripheral leukocytes. RESULTS: The hypertrichosis score was higher in the cases compared to controls. Serum gonadotropins and sex steroids were similar in both groups, but SHBG was significantly lower in the girls with hypertrichosis (71.1 ± 2.9 vs 81.9 ± 3.0 nmol/L, p < 0.02). The distribution of shorter, larger and total alleles was not statistically different between cases and controls. The combined analysis of CAG/GGC, however, showed a significantly higher prevalence of the most androgen-sensitive haplotypes (1-2: <22CAG + 17/17GGC- < 14CAG + 17/18GGC) in girls with hypertrichosis compared to controls. CONCLUSIONS: We conclude that girls with hypertrychosis exhibit AR(s) with enhanced sensitivity, which may facilitate the growth of their body hair.

The role of androst-5-ene-3ß,17ß-diol (androstenediol) in cell proliferation in endometrium of women with polycystic ovary syndrome.

Women with polycystic ovary syndrome (PCOS) show high prevalence of endometrial hyperplasia and adenocarcinoma. Endometrial proliferation is increased, evaluated by high levels of Ki67 (cell cycle marker) and low levels of p27 (negative regulator of cell cycle). Nevertheless, endometrial changes in cyclin D1 (positive regulator of cell cycle) in PCOS-women are not described. Androst-5-ene-3ß,17ß-diol (androstenediol), steroid with estrogenic activity present in endometria, could be related to increased endometrial cell proliferation. The objective of this study was to determine protein content of cyclin D1 and androstenediol levels in endometria from PCOS and control-women and to evaluate the possible mechanism favoring cell proliferation associated with hormonal characteristics of patients. Therefore, cyclin D1 protein content in PCOS-women and control-endometrial tissue were assessed by western blot and immunohistochemistry. The androstenediol levels were evaluated by ELISA. To further analyze the effect of steroids (androstenediol, 17ß-estradiol, testosterone) in cell proliferation, levels of proteins cyclin D1, p27 and Ki67 were evaluated in an in vitro model of stromal endometrial cells T-HESC and St-T1b. An increase in cyclin D1 and androstenediol was observed in tissues from PCOS-women relative to control group (p<0.05). In the in vitro model, androstenediol exerted increase in cyclin D1 (p<0.05) and a decrease in p27 protein level (p<0.05), while Ki67 in St-T1b cells increased under this stimulus (p<0.05). Testosterone produces opposite effects in the levels of the above markers (p<0.05). Therefore, the hormonal imbalance associated with this syndrome could alter endometrial tissue homeostasis, promoting cell proliferation. Androstenediol is a molecule that could be involved by stimulating proliferation, whereas testosterone elicits a role of cell cycle repressor.

Opposing roles of PKA and EPAC in the cAMP-dependent regulation of schwann cell proliferation and differentiation [corrected].

In Schwann cells (SCs), cyclic adenosine monophosphate (cAMP) not only induces differentiation into a myelinating SC-related phenotype, but also synergistically enhances the mitogenic action of growth factors such as neuregulin. To better understand the molecular mechanism by which cAMP exerts these apparently contradictory functions, we investigated the role of the two main effectors of cAMP, protein kinase A (PKA) and the exchange protein activated by cAMP (EPAC), on the proliferation and differentiation of both isolated and axon-related SCs. For these studies, a variety of PKA and EPAC agonists and antagonists were used, including pathway-selective analogs of cAMP and pharmacological inhibitors. Our studies indicated that the activity of PKA rather than EPAC was required for the adjuvant effect of cAMP on S-phase entry, whereas the activity of EPAC rather than PKA was required for SC differentiation and myelin formation. Even though selective EPAC activation had an overall anti-proliferative effect in SCs, it failed to drive the expression of Krox-20, a master regulator of myelination, and that of myelin-specific proteins and lipids, suggesting that EPAC activation was insufficient to drive a full differentiating response. Interestingly, inhibition of EPAC activity resulted in a drastic impairment of SC differentiation and myelin formation but not Krox-20 expression, which indicates an independent mechanism of Krox-20 regulation in response to cAMP. In conclusion, our data supports the idea that the outcome of cAMP signaling in SCs depends on the particular set of effectors activated. Whereas the mitogenic action of cAMP relies exclusively on PKA activity, the differentiating action of cAMP requires a PKA-independent (non-canonical) cAMP-specific pathway that is partially transduced by EPAC.

Androgen receptor gene CAG and GGN repeat polymorphisms in Chilean men with primary severe spermatogenic failure.

There is ample documentation supporting the fact that androgens are required for normal spermatogenesis. A minority of infertile men have abnormal testosterone blood levels or mild androgen receptor mutations. We investigated the androgen receptor CAG and GGN repeat lengths in Chilean men with spermatogenic impairment. We studied 117 secretory azoospermic/oligozoospermic men (93 idiopathic and 24 excryptorchidic), without Y-chromosome microdeletions, and 121 controls with normal spermatogenesis (42 obstructive and 79 normozoospermic men). Peripheral blood was drawn to obtain genomic DNA for polymerase chain reaction and automated sequencing of CAG and GGN repeats. Testicular characterization included hormonal studies, physical evaluation, and seminal and biopsy analysis. The CAG and GGN polymorphism distributions were similar among idiopathic men, excryptorchidic men, and controls and among the different types of spermatogenic impairment. However, the proportion of the CAG 21 allele was significantly increased in idiopathic cases compared to controls (P = .012 by Bonferroni test, odds ratio = 2.99, 95% confidence interval, 1.27-7.0) and the CAG 32 allele only was observed in excryptorchidic patients (P < .0002, Bonferroni test). Idiopathic cases with Sertoli cell-only syndrome showed the highest proportion of the CAG 21 allele (P = .024, χ(2) test). On the other hand, in idiopathic cases and controls the most common GGN allele was 23, followed by 24, but an inverse relation was found among excryptorchidic cases. The joint distribution of CAG and GGN in control, idiopathic, and excryptorchidic groups did not show an association between the 2 allele repeat polymorphisms (P > 0.05, χ(2) test). Our results suggest that the CAG 21 allele seems to increase the risk of idiopathic Sertoli cell-only syndrome. Moreover, the GGN 24 allele could be contributing to deranged androgen receptor function, associated with cryptorchidism and spermatogenic failure.

Sex hormone-binding globulin expression in the endometria of women with polycystic ovary syndrome.

OBJECTIVE: To evaluate the protein and messenger RNA expression of sex hormone-binding globulin (SHBG) in endometria from women with polycystic ovary syndrome (PCOS). DESIGN: Case-control study. SETTING: Hospital research unit. PATIENT(S): Thirty-three women with PCOS, and 17 fertile, healthy women of similar age to those with PCOS. INTERVENTION(S): Endometrial and blood samples were obtained from women with PCOS (PCOSEs) and from control women (CEs) during the proliferative phase of the menstrual cycle. MAIN OUTCOME MEASURE(S): Expression studies for SHBG (immunohistochemistry and reverse transcription-polymerase chain reaction). Hormonal studies for determining sex steroids (T, P, and E(2)) and SHBG concentration. Insulin sensitivity was assessed by composite insulin sensitivity index (ISI(composite)). RESULT(S): In stroma, the protein expression of SHBG was lower in PCOSEs than in CEs. Epithelial cells had a similar expression of SHBG protein in both groups. Messenger RNA of variant 548 base pairs (wild-type) tended to be lower in PCOSEs compared to CEs. When PCOSEs were classified by insulin resistance, the PCOSEs with normal insulin sensitivity showed an expression of stromal SHBG similar to that observed in CEs. CONCLUSION(S): The low SHBG expression in the stromal compartment of endometria from women with PCOS with insulin resistance may contribute to generate an abnormal steroid milieu in the endometria of these women.