Cocaine- and amphetamine-regulated transcript accelerates termination of follicle-stimulating hormone-induced extracellularly regulated kinase 1/2 and Akt activation by regulating the expression and degradation of specific mitogen-activated protein kinase phosphatases in bovine granulosa cells

Follicular Atresia in Buffalo: Cocaine- and Amphetamine-Regulated Transcript (CART) and the Underlying Mechanisms

Atresia is a process in ovarian follicles that is regulated by hormone-induced apoptosis. During atresia, granulosa cell (GC) apoptosis is a key mechanism orchestrated through diverse signaling pathways. Cocaine- and amphetamine-regulated transcript (CART) signaling within ovarian GCs has been demonstrated to play a key role in the regulation of follicular atresia in cattle, pigs, and sheep. The present work aimed to investigate the potential local regulatory role of CART in GC apoptosis-induced follicular atresia in buffalo, focusing on the modulation of the AKT/GSK3β/β-catenin signaling pathways, which are the intracellular signaling pathways involved in cell viability. Our findings revealed increased expression of CARTPT and BAX and decreased levels of AKT, β-catenin, and CYP19A1 genes in atretic follicles compared to healthy follicles. Subsequently, CART treatment in the presence of FSH inhibited the FSH-induced increase in GC viability by reducing estradiol production and increasing apoptosis. This change was accompanied by an increase in the gene expression levels of both CARTPT and BAX. At the protein level, treatment with CART in the presence of FSH negatively affected the activity of AKT, β-catenin, and LEF1, while the activity of GSK3β was enhanced. In conclusion, our study shows how CART negatively influences buffalo GC viability, underlying the modulation of the AKT/GSK3β/β-catenin pathway and promoting apoptosis-a key factor in follicular atresia.

The Role of Cocaine- and Amphetamine-Regulated Transcript (CART) in Cancer: A Systematic Review

The functions of cocaine- and amphetamine-regulated transcript (CART) neuropeptide encoded by the CARTPT gene vary from modifying behavior and pain sensitivity to being an antioxidant. Putative CART peptide receptor GPR160 was implicated recently in the pathogenesis of cancer. However, the exact role of CART protein in the development of neoplasms remains unclear. This systematic review includes articles retrieved from the Scopus, PubMed, Web of Science and Medline Complete databases. Nineteen publications that met the inclusion criteria and describe the association of CART and cancer were analyzed. CART is expressed in various types of cancer, e.g., in breast cancer and neuroendocrine tumors (NETs). The role of CART as a potential biomarker in breast cancer, stomach adenocarcinoma, glioma and some types of NETs was suggested. In various cancer cell lines, CARTPT acts an oncogene, enhancing cellular survival by the activation of the ERK pathway, the stimulation of other pro-survival molecules, the inhibition of apoptosis or the increase in cyclin D1 levels. In breast cancer, CART was reported to protect tumor cells from tamoxifen-mediated death. Taken together, these data support the role of CART activity in the pathogenesis of cancer, thus opening new diagnostic and therapeutic approaches in neoplastic disorders.

Looking at the Future Through the Mother's Womb: Gestational Diabetes and Offspring Fertility

Altered nutrition or intrauterine exposure to various adverse conditions during fetal development or earlier in a mother's life can lead to epigenetic changes in fetal tissues, predisposing those tissues to diseases that manifest when offspring become adults. An example is a maternal obesity associated with gestational diabetes (GDM), where fetal exposure to a hyperglycemic, hyperinsulinemic, and/or hyperlipidemic gestational environment can provoke epigenetic changes that predispose offspring to various diseased conditions later in life. While it is now well established that offspring exposed to GDM have an increased risk of developing obesity, metabolic disorders, and/or cardiovascular disease in adult life, there are limited studies assessing the reproductive health of these offspring. This mini-review discusses the long-term effect of in utero exposure to GDM-associated adverse prenatal environment on the reproductive health of the offspring. Moreover, using evidence from various animal models and human epidemiological studies, this review offers molecular insight and understanding of how epigenetic reprogramming of genes culminates in reproductive dysfunction and the development of subfertility or infertility later in adult life.

Amphetamine-Decreased Progesterone and Estradiol Release in Rat Granulosa Cells: The Regulatory Role of cAMP- and Ca2+-Mediated Signaling Pathways

The purpose of this study is to evaluate the amphetamine effects on progesterone and estradiol production in rat granulosa cells and the underlying cellular regulatory mechanisms. Freshly dispersed rat granulosa cells were cultured with various test drugs in the presence of amphetamine, and the estradiol/progesterone production and the cytosolic cAMP level were measured. Additionally, the cytosolic-free Ca²⁺ concentrations ([Ca²⁺]i) were measured to examine the role of Ca²⁺ influx in the presence of amphetamine. Amphetamine in vitro inhibited both basal and porcine follicle-stimulating hormone-stimulated estradiol/progesterone release, and amphetamine significantly decreased steroidogenic enzyme activities. Adding 8-Bromo-cAMP did not recover the inhibitory effects of amphetamine on progesterone and estradiol release. H89 significantly decreased progesterone and estradiol basal release but failed to enhance a further amphetamine inhibitory effect. Amphetamine was capable of further suppressing the release of estradiol release under the presence of nifedipine. Pretreatment with the amphetamine for 2 h decreased the basal [Ca²⁺]i and prostaglandin F2α-stimulated increase of [Ca²⁺]i. Amphetamine inhibits progesterone and estradiol secretion in rat granulosa cells through a mechanism involving decreased PKA-downstream steroidogenic enzyme activity and L-type Ca²⁺ channels. Our current findings show that it is necessary to study the possibility of amphetamine perturbing reproduction in females.

Should I Lay or Should I Grow: Photoperiodic Versus Metabolic Cues in Chickens

While photoperiod has been generally accepted as the primary if not the exclusive cue to stimulate reproduction in photoperiodic breeders such as the laying hen, current knowledge suggests that metabolism, and/or body composition can also play an influential role to control the hypothalamic-pituitary gonadal (HPG)-axis. This review thus intends to first describe how photoperiodic and metabolic cues can impact the HPG axis, then explore and propose potential common pathways and mechanisms through which both cues could be integrated. Photostimulation refers to a perceived increase in day-length resulting in the stimulation of the HPG. While photoreceptors are present in the retina of the eye and the pineal gland, it is the deep brain photoreceptors (DBPs) located in the hypothalamus that have been identified as the potential mediators of photostimulation, including melanopsin (OPN4), neuropsin (OPN5), and vertebrate-ancient opsin (VA-Opsin). Here, we present the current state of knowledge surrounding these DBPs, along with their individual and relative importance and, their possible downstream mechanisms of action to initiate the activation of the HPG axis. On the metabolic side, specific attention is placed on the hypothalamic integration of appetite control with the stimulatory (Gonadotropin Releasing Hormone; GnRH) and inhibitory (Gonadotropin Inhibitory Hormone; GnIH) neuropeptides involved in the control of the HPG axis. Specifically, the impact of orexigenic peptides agouti-related peptide (AgRP), and neuropeptide Y (NPY), as well as the anorexigenic peptides pro-opiomelanocortin (POMC), and cocaine-and amphetamine regulated transcript (CART) is reviewed. Furthermore, beyond hypothalamic control, several metabolic factors involved in the control of body weight and composition are also presented as possible modulators of reproduction at all three levels of the HPG axis. These include peroxisome proliferator-activated receptor gamma (PPAR-γ) for its impact in liver metabolism during the switch from growth to reproduction, adiponectin as a potential modulator of ovarian development and follicular maturation, as well as growth hormone (GH), and leptin (LEP).

Gestational Diabetes Epigenetically Reprograms the Cart Promoter in Fetal Ovary, Causing Subfertility in Adult Life

Intrauterine exposure to various adverse conditions during fetal development can lead to epigenetic changes in fetal tissues, predisposing those tissues to disease conditions later in life. An example is gestational diabetes (GD), where the offspring has a higher risk of developing obesity, metabolic disorders, or cardiovascular disease in adult life. In this study, using two well-established GD (streptozotocin- and high-fat and high-sugar-induced) mouse models, we report that female offspring from GD dams are predisposed toward fertility problems later in life. This predisposition to fertility problems is due to altered ovarian expression of a peptide called cocaine- and amphetamine-regulated transcript (CART), which is known to negatively affect folliculogenesis and is induced by elevated leptin levels. Results show that the underlying cause of this altered expression is due to fetal epigenetic modifications involving glucose- and insulin-induced miRNA, miR-101, and the phosphatidylinositol 3-kinase/Akt pathway. These signaling events regulate Ezh2, a histone methyltransferase that promotes H3K27me3, a gene-repressive mark, and CBP/p300, a histone acetyltransferase that promotes H3K27ac, a transcription activation mark, in the fetal ovary. Moreover, the CART promoter has depleted 5-methylcytosine (5mC) and enriched 5-hydroxymethylcytosine (5hmC) levels. The depletion of H3K27me3 and 5mC repressive marks and subsequent increase in H3K27ac and 5hmC gene-activating marks convert the Cartpt promoter to a "superpromoter." This makes the Cartpt promoter more sensitive to leptin levels that predispose the GD offspring to fertility problems. Therefore, this study provides a mechanistic insight about fetal epigenome reprogramming that manifests to ovarian dysfunction and subfertility later in adult life.

Study on the relationship between expression patterns of cocaine-and amphetamine regulated transcript and hormones secretion in porcine ovarian follicles

Background

Cocaine-and amphetamine regulated transcript (CART) is an endogenous neuropeptide, which is widespread in animals, plays a key role in regulation of follicular atresia in cattle and sheep. Among animal ovaries, CART mRNA was firstly found in the cattle ovaries. CART was localized in the antral follicles oocytes, granulosa and cumulus cells by immunohistochemistry and in situ hybridization. Further research found that secretion of E₂ was inhibited in granulosa cells with a certain dose of CART, the effect depends on the stage of cell differentiation, suggesting that CART could play a crucial role in regulating follicle atresia. The objective of this study was to characterize the CART expression model and hormones secretion in vivo and vitro in pig follicle granulosa cells, preliminarily studied whether CART have an effect on granulosa cells proliferation and hormones secretion in multiparous animals such as pigs.

Methods

The expression levels of CART mRNA in granulosa cells of different follicles were analyzed using qRT-PCR technology. Immunohistochemistry technology was used to localize CART peptide. Granulosa cells were cultured in medium supplemented with different concentrations of CART and FSH for 168 h using Long-term culture system, and observed using a microscope. The concentration of Estradiol (E₂) and progesterone (P) in follicular fluids of different test groups were detected by enzyme linked immunosorbent assay (ELISA).

Results

Results showed that expression level of CART mRNA was highest in medium follicles, and significantly higher than that in large and small follicles (P < 0.05). Immunohistochemical results showed that CART were expressed both in granulosa cells and theca cells of large follicles, while CART were detected only in theca cells of medium and small follicles. After the granulosa cells were cultured for 168 h, and found that concentrations of E₂ increase with concentrations of follicle-stimulating hormone (FSH) increase when the CART concentration was 0 μM. And the concentration of FSH reached 25 ng/mL, the concentration of E₂ is greatest. It shows that the production of E₂ needs induction of FSH in granulosa cells of pig ovarian follicles. With the increasing of CART concentrations (0.01, 0.1, 1 μM), E₂ concentration has a declining trend, when the FSH concentrations were 25 and 50 ng/mL in the medium, respectively.

Conclusions

These results suggested that CART plays a role to inhibit granulosa cells proliferation and E₂ production, which induced by FSH in porcine ovarian follicular granulosa cells in vitro, but the inhibition effect is not significant. So we hypothesis CART maybe not a main local negative regulatory factor during porcine follicular development, which is different from the single fetal animals.

Expression of cocaine- and amphetamine-regulated transcript (CART) in hen ovary

Background

Cocaine- and amphetamine-regulated transcript (CART), discovered initially by via differential display RT-PCR analysis of brains of rats administered cocaine, is expressed mainly in central nervous system or neuronal origin cells, and is involved in a wide range of behaviors, such as regulation of food intake, energy homeostasis, and reproduction. The hens egg-laying rate mainly depends on the developmental status of follicles, expression of CART have not been identified from hen follicles, the regulatory mechanisms of CART biological activities are still unknown. The objective of this study was to characterize the mRNA expression of CART in hen follicular granulosa cells and determine CART peptide localization and regulatory role during follicular development.

Methods

Small white follicles (1–2 mm in diameter) were treated for RNA isolation; Small white follicles (1–2 mm in diameter) and large white follicles (4–6 mm in diameter) were treated for immunohistochemical localization and large white follicles (4–6 mm in diameter), small yellow follicles (6–8 mm in diameter), large yellow follicles (9–12 mm in diameter), mature follicles (F5, F4, F3, F2, F1, >12 mm in diameter) were treated for RNA isolation and Real time PCR.

Results

The results showed that full length of the CDS of hen CART was 336 bp encoding a 111 amino acid polypeptide. In the hen ovary, CART peptide was primarily localized to the theca layer, but not all, the oocyte and granulosa layer, with diffused, weaker staining than relative to the theca cell layer. Further, amount of CART mRNA was more (P < 0.05) in granulosa cells of 6–8 mm follicles compared with that in granulosa cells of other follicles. However, CART mRNA amount was greater in theca cells of 4–6 mm follicles relative to follicles of other sizes (P < 0.05).

Conclusions

Results suggest that CART could play a potential role in developmental regulation of chicken follicles.

Differential expression of CART in ewes with differing ovulation rates

We hypothesised that cocaine- and amphetamine-regulated transcript (CARTPT) would be differentially expressed in ewes with differing ovulation rates. Expression of mRNA forCARTPT, as well asLHCGR,FSHR,CYP19A1andCYP17A1was determined in antral follicles ≥1 mm in diameter collected during the follicular phase in ewes heterozygous for the Booroola and Inverdale genes (I+B+; average ovulation rate 4) and ++ contemporaries (++; average ovulation rate 1.8). In ++ ewes (n = 6),CARTPTwas expressed in small follicles (1 to <3 mm diameter), where 18.8 ± 2.5% follicles expressedCARTPT. CART peptide was also detected in follicular fluid of some follicles of ++ ewes. In I+B+ ewes, 5/6 ewes did not have any follicles that expressedCARTPT, and no CART peptide was detected in any follicle examined. Expression pattern ofCYP19A1differed between I+B+ and ++ ewes with an increased percentage of small and medium follicles (3 to <4.5 mm diameter) but decreased percentage of large follicles (≥4.5 mm diameter) expressingCYP19A1in the I+B+ ewes. Many of the large follicles from the I+B+ ewes appeared non-functional and expression ofLHCGR,FSHR,CYP17A1andCYP19A1was less than that observed in ++ ewes. Expression ofFSHRandCYP17A1was not different between groups in small and medium follicles, butLHCGRexpression was approximately double in I+B+ ewes compared to that in ++ ewes. Thus, ewes with high ovulation rates had a distinct pattern of expression ofCARTPTmRNA and protein compared to ewes with normal ovulation rates, providing evidence for CART being important in the regulation of ovulation rate.

Notch signaling pathway promotes the development of ovine ovarian follicular granulosa cells

The Notch signaling pathway regulates cell proliferation, differentiation and apoptosis involved in development of the organs and tissues such as nervous system, cartilage, lungs, kidneys and prostate as well as the ovarian follicles. This study aimed to investigate the mRNA expression and localization of NOTCH2, as the key factor in Notch signaling pathway. This was determined by PCR, real-time PCR and immunohistochemistry. Additionally, the effects of inhibiting Notch signaling pathway with different concentrations (5μM, 10μM and 20μM) of N-[N-(3, 5-Difuorophenacetyl)-l-alanyl]-S-phenylglycine t-butyl ester (DAPT), an inhibitor of Notch signaling pathway, on ovine granulosa cells was determined in vitro by detecting estradiol production using enzyme linked immunosorbent assay and expressions of the genes related to the cell cycle and apoptosis using real-time polymerase chain reaction (PCR). NOTCH2, the key member of Notch signaling pathway, was found in ovine follicles, and the expression of NOTCH2 mRNA was highest in the theca cells of the follicles in medium sizes (3-5mm in diameter) and granulosa cells of the follicles in large sizes (>5mm in diameter). Immunohistochemical results demonstrated that NOTCH2 protein was expressed in granulosa cells of preantral follicles, in both granulosa cells and theca cells of antral follicles. Compared with DAPT-treated groups, the control group had a higher number of granulosa cells (P<0.05) and a higher estradiol production (P<0.05). Compared with the control group, the mRNA abundances of HES1, MYC, BAX, BCL2 and CYP19A1 in DAPT-treated groups was lower (P<0.05), respectively; whereas, the expression of CCND2, CDKN1A and TP53 mRNA showed no remarkable difference compared with control group. Collectively, Notch signaling pathway could be involved in the ovine follicular development by regulating the growth and estradiol production of granulosa cells.

Cocaine- and amphetamine-regulated transcript: a novel regulator of energy homeostasis expressed in a subpopulation of pancreatic islet cells

Type 2 diabetes is characterised by chronic hyperglycaemia and its incidence is highly increased by exaggerated food consumption. It results from a lack of insulin action/production, but growing evidence suggests that it might also involve hyperglucagonaemia and impaired control of glucose homeostasis by the brain. In recent years, the cocaine and amphetamine-regulated transcript (CART) peptides have generated a lot of interest in the battle against obesity because, via the brain, they exert anorexic effects and they increase energy expenditure. They are also localised, outside the brain, in discrete regions of the body and play a hormonal role in controlling various functions. In this issue of Diabetologia, the Wierup group (doi: 10.1007/s00125-016-4020-6 ) shows that CART peptides are expressed heterogeneously in islet cells of various species, including humans, and that their expression is upregulated in diabetes. The authors also shine a spotlight on some interesting effects of CART peptides on islet function, including stimulation of insulin secretion and inhibition of glucagon release. CART peptides would thus be at the centre of a cooperation between the brain and the endocrine pancreas to control glucose homeostasis. Although the mechanisms of action of CART peptides remain enigmatic because no specific receptor for these peptides has so far been discovered, their potential therapeutic use is evident and represents a new challenge for future research.

Leptin-Induced CART (Cocaine- and Amphetamine-Regulated Transcript) Is a Novel Intraovarian Mediator of Obesity-Related Infertility in Females

Obesity is considered detrimental to women's reproductive health. Although most of the attention has been focused on the effects of obesity on hypothalamic function, studies suggest a multifactorial impact. In fact, obesity is associated with reduced fecundity even in women with regular cycles, indicating that there may be local ovarian effects modulating fertility. Here we describe a novel mechanism for leptin actions directly in the ovary that may account for some of the negative effects of obesity on ovarian function. We find that normal cycling, obese, hyperleptinemic mice fed with a high-fat diet are subfertile and ovulate fewer oocytes compared with animals fed with a normal diet. Importantly, we show that leptin induces expression of the neuropeptide cocaine- and amphetamine-regulated transcript (CART) in the granulosa cells (GCs) of ovarian follicles both in vitro and in vivo. CART then negatively affects intracellular cAMP levels, MAPK signaling, and aromatase mRNA expression, which leads to lower estradiol synthesis in GCs and altered ovarian folliculogenesis. Finally, in human samples from patients undergoing in vitro fertilization, we show a significant positive correlation between patient body mass index, CART mRNA expression in GCs, and CART peptide levels in follicular fluid. These observations suggest that, under obese conditions, CART acts as a local mediator of leptin in the ovary to cause ovarian dysfunction and reduced fertility.

Intrafollicular expression and potential regulatory role of cocaine- and amphetamine-regulated transcript in the ovine ovary

Follicular growth is regulated by a complex interaction of pituitary gonadotropins with local regulatory molecules. Previous studies demonstrated an important role for cocaine- and amphetamine-regulated transcript (CART) in regulation of granulosa cell estradiol production associated with dominant follicle selection in cattle. However, intraovarian expression and actions of CART in other species, including sheep, are not known. The objective of this study was to investigate the expression of CART in sheep follicles and determine the effects of CART on indices of ovine granulosa cell function linked to follicular development. Results demonstrated the expression of CART messenger RNA and prominent intraovarian localization of CART peptide in granulosa cells of sheep follicles. Granulosa cell CART messenger RNA was lower, but follicular fluid estradiol concentrations were higher in large (>5 mm) follicles vs smaller 3- to 5-mm follicles harvested from sheep ovaries of abattoir origin. CART treatment inhibited follicle stimulating hormone-induced estradiol production by cultured ovine granulosal cells and also blocked the follicle stimulating hormone-induced increase in granulosa cell numbers. Results demonstrate expression of CART in sheep follicular tissues and suggest potential biological actions of CART, which are inhibitory to ovine follicular growth and development.

Regulation and regulatory role of WNT signaling in potentiating FSH action during bovine dominant follicle selection

Follicular development occurs in wave like patterns in monotocous species such as cattle and humans and is regulated by a complex interaction of gonadotropins with local intrafollicular regulatory molecules. To further elucidate potential mechanisms controlling dominant follicle selection, granulosa cell RNA harvested from F1 (largest) and F2 (second largest) follicles isolated at predeviation (PD) and onset of diameter deviation (OD) stages of the first follicular wave was subjected to preliminary RNA transcriptome analysis. Expression of numerous WNT system components was observed. Hence experiments were performed to test the hypothesis that WNT signaling modulates FSH action on granulosa cells during follicular waves. Abundance of mRNA for WNT pathway members was evaluated in granulosa cells harvested from follicles at emergence (EM), PD, OD and early dominance (ED) stages of the first follicular wave. In F1 follicles, abundance of CTNNB1 and DVL1 mRNAs was higher and AXIN2 mRNA was lower at ED versus EM stages and DVL1 and FZD6 mRNAs were higher and AXIN2 mRNA was lower in F1 versus F2 follicle at the ED stage. Bovine granulosa cells were treated in vitro with increasing doses of the WNT inhibitor IWR-1+/- maximal stimulatory dose of FSH. IWR-1 treatment blocked the FSH-induced increase in granulosa cell numbers and reduced the FSH-induced increase in estradiol. Granulosa cells were also cultured in the presence or absence of FSH +/- IWR-1 and hormonal regulation of mRNA for WNT pathway members and known FSH targets determined. FSH treatment increased CYP19A1, CCND2, CTNNB1, AXIN2 and FZD6 mRNAs and the stimulatory effect on CYP19A1 mRNA was reduced by IWR-1. In contrast, FSH reduced CARTPT mRNA and IWR-1 partially reversed the inhibitory effect of FSH. Results support temporal and hormonal regulation and a potential role for WNT signaling in potentiating FSH action during dominant follicle selection.

CART (cocaine- and amphetamine-regulated transcript) peptide specific binding sites in PC12 cells have characteristics of CART peptide receptors

CART (cocaine- and amphetamine-regulated transcript) peptide is a neuropeptide with a powerful central anorexigenic effect. Specific CART peptide binding sites, most likely CART peptide receptors, have been found in PC12 cells. This study further characterizes the CART peptide binding sites in PC12 cells. After differentiation to a neuronal phenotype with nerve growth factor, the number of CART peptide binding sites in PC12 cells tripled. Following dexamethasone treatment, which transforms PC12 cells into chromaffin-like cells, the number of CART peptide binding sites substantially decreased. CART peptide did not affect the differentiation or acetylcholinesterase activity of PC12 cells, indicating that CART peptide does not participate in differentiation or neuronal activity. CART peptide increased the phosphorylation of SAPK/JNK (stress-activated protein kinase/c-Jun-amino-terminal kinase) and subsequent c-Jun protein expression. These effects were reversed by SP600125, a specific JNK-kinase inhibitor. CART peptide did not significantly affect ERK (extracellular signal-regulated kinase), CREB (cAMP responsive element binding protein), or p38 phosphorylation and c-Fos protein expression. Central administration of CART peptide into mice also resulted in increased c-Jun positive cells in dorsomedial hypothalamic nucleus and nucleus of the solitary tract, areas involved in food intake regulation. Activation of c-Jun by CART peptide might indicate a possible role of CART peptide in managing stress conditions rather than a role in cell proliferation or differentiation as well as the more complex and/or specific regulation ways by transcription factors in some nuclei involved in food intake regulation. The characteristics of stress that CART peptide potentially mediates should be further studied.

Regulation of granulosa cell cocaine and amphetamine regulated transcript (CART) binding and effect of CART signaling inhibitor on granulosa cell estradiol production during dominant follicle selection in cattle

We previously established a potential role for cocaine and amphetamine regulated transcript (CARTPT) in dominant follicle selection in cattle. CARTPT expression is elevated in subordinate versus dominant follicles, and treatment with the mature form of the CARTPT peptide (CART) decreases follicle-stimulating hormone (FSH)-stimulated granulosa cell estradiol production in vitro and follicular fluid estradiol and granulosa cell CYP19A1 mRNA in vivo. However, mechanisms that regulate granulosa cell CART responsiveness are not understood. In this study, we investigated hormonal regulation of granulosa cell CART-binding sites in vitro and temporal regulation of granulosa cell CART-binding sites in bovine follicles collected at specific stages of a follicular wave. We also determined the effect of inhibition of CART receptor signaling in vivo on estradiol production in future subordinate follicles. Granulosa cell CART binding in vitro was increased by FSH, and this induction was blocked by estrogen receptor antagonist treatment. In follicles collected in vivo at specific stages of a follicular wave, granulosa cell CART binding in the F2 (second largest), future subordinate follicle increased during dominant follicle selection. Injection into the F2 follicle (at onset of diameter deviation) of an inhibitor of the o/i subclass of G proteins (previously shown to block CART actions in vitro) resulted in increased follicular fluid estradiol concentrations in vivo. Collectively, results demonstrate hormonal regulation of granulosa cell CART binding in vitro and temporal regulation of CART binding in subordinate follicles during dominant follicle selection. Results also suggest that CART signaling may help suppress estradiol-producing capacity of the F2 (subordinate) follicle during this time period.

Identification and location of the cocaine and amphetamine regulated transcript (CART) in the abomasum of cattle

The cocaine and amphetamine regulated transcript (CART) belongs to the group of peptides with anorexigenic properties and is present in many areas of the central and peripheral nervous systems of numerous mammalian species. Research has suggested an effect on the feeling of appetite and satiety; however, there are no clear clues as to the role of CART in specific organs, including the stomach. Considering the specificity of cattle feeding and digestion, CART may play a highly significant role possibly associated with the option of administering greater amounts of high-volume feeds. Based on the results of immunohistochemical staining of abomasum samples prepared from hybrid bulls, the presence of CART-positive structures and CART distribution were determined in the mucosa, submucosa and muscularis layers of the stomach. Abundant sites of CART were found in the myenteric plexus, nerve fibers innervating the myocytes of the myenteron, neuroendocrine cells of the diffuse neuroendocrine system and the submucous plexus. The preliminary stage of abomasal CART detection suggests that CART is an agent that strongly affects the regulation of motor activity involved in stomach emptying and in secretory functions of the stomach. However, further research is necessary to explain the relationship.

Stage-specific expression and effect of bone morphogenetic protein 2 on bovine granulosa cell estradiol production: regulation by cocaine and amphetamine regulated transcript

Members of the bone morphogenetic protein (BMP) family regulate follicular development and granulosa cell function. However, changes in expression of BMP2 and its receptors during follicular waves in cattle and ability of BMP2 to modulate bovine granulosa cell estradiol production are not well understood. The objectives of this study were to determine temporal regulation of mRNA for BMP2 and its type I and II receptors (BMPR1A and BMPR2) in bovine follicles collected at specific stages of a follicular wave (predeviation, early dominance, mid dominance, preovulatory), ability of BMP2 to modulate bovine granulosa cell steroidogenesis, and whether effects of BMP2 on granulosa cell estradiol production are influenced by cotreatment with cocaine- and amphetamine-regulated transcript (CART), an intrafollicular regulatory peptide shown to inhibit estradiol production in response to other trophic hormones (FSH and IGF1). Relative abundance of mRNAs for Bmp2 and Bmpr2 was elevated at the mid dominance stage relative to earlier stages of the follicular wave and further increased at the preovulatory stage. Abundance of mRNA for Bmpr1a was lowest at early dominance stage and highest at preovulatory stage relative to other stages of the follicular wave examined. Treatment of bovine granulosa cells in vitro with BMP2 increased estradiol but decreased progesterone concentrations. Co-incubation with CART reduced the BMP2-stimulated increase in granulosa cell estradiol production. Results suggest that BMP2 may play a regulatory role in development of bovine follicles to the preovulatory stage and that CART can inhibit granulosa cell estradiol production in response to multiple hormones/growth factors, including BMP2.

Roles of cocaine- and amphetamine-regulated transcript in the central nervous system

1. Cocaine- and amphetamine-regulated transcript (CART), first isolated from the ovine hypothalamus, is a potential neurotransmitter widely distributed throughout the central and peripheral nervous systems, as well as in endocrine cells in the pituitary and adrenal glands, pancreatic islets and stomach. 2. Numerous studies have established the role of CART in food intake, maintenance of bodyweight, stress control, reward and pain transmission. Recently, it was demonstrated that CART, as a neurotrophic peptide, had a cerebroprotective against focal ischaemic stroke and inhibited the neurotoxicity of β-amyloid protein, which focused attention on the role of CART in the central nervous system (CNS) and neurological diseases. 3. In fact, little is known about the way in which CART peptide interacts with its receptors, initiates downstream cascades and finally exerts its neuroprotective effect under normal or pathological conditions. The literature indicates that there are many factors, such as regulation of the immunological system and protection against energy failure, that may be involved in the cerebroprotection afforded by CART. 4. The present review provides a brief summary of the current literature on CART synthesis and active fragments, its distribution in the CNS and, in particular, the role of CART peptide (and its receptors and signalling) in neurological diseases.

The cocaine- and amphetamine-regulated transcript mediates ligand-independent activation of ERα, and is an independent prognostic factor in node-negative breast cancer

Personalized medicine requires the identification of unambiguous prognostic and predictive biomarkers to inform therapeutic decisions. Within this context, the management of lymph node-negative breast cancer is the subject of much debate with particular emphasis on the requirement for adjuvant chemotherapy. The identification of prognostic and predictive biomarkers in this group of patients is crucial. Here, we demonstrate by tissue microarray and automated image analysis that the cocaine- and amphetamine-regulated transcript (CART) is expressed in primary and metastatic breast cancer and is an independent poor prognostic factor in estrogen receptor (ER)-positive, lymph node-negative tumors in two separate breast cancer cohorts (n=690; P=0.002, 0.013). We also show that CART increases the transcriptional activity of ERα in a ligand-independent manner via the mitogen-activated protein kinase pathway and that CART stimulates an autocrine/paracrine loop within tumor cells to amplify the CART signal. Additionally, we demonstrate that CART expression in ER-positive breast cancer cell lines protects against tamoxifen-mediated cell death and that high CART expression predicts disease outcome in tamoxifen-treated patients in vivo in three independent breast cancer cohorts. We believe that CART profiling will help facilitate stratification of lymph node-negative breast cancer patients into high- and low-risk categories and allow for the personalization of therapy.

Expression of CART peptide in the paleoamygdala neurons and its relationship with sex hormone levels

The location of CART peptide in the paleoamygdala neurons was studied by immunocytochemical reaction. Significant differences in the number of immunoreactive cells and optical density of CART-positive neurons detected over the course of the estrous cycle indicate modulating effects of sex steroids on the expression of CART peptide.