Neurotransmitter receptors as signaling platforms in anterior pituitary cells

Adaptation of the Porcine Pituitary Transcriptome, Spliceosome and Editome during Early Pregnancy

The physiological mechanisms of the porcine reproduction are relatively well-known. However, transcriptomic changes and the mechanisms accompanying transcription and translation processes in various reproductive organs, as well as their dependence on hormonal status, are still poorly understood. The aim of this study was to gain a principal understanding of alterations within the transcriptome, spliceosome and editome occurring in the pituitary of the domestic pig (Sus scrofa domestica L.), which controls basic physiological processes in the reproductive system. In this investigation, we performed extensive analyses of data obtained by high-throughput sequencing of RNA from the gilts' pituitary anterior lobes during embryo implantation and the mid-luteal phase of the estrous cycle. During analyses, we obtained detailed information on expression changes of 147 genes and 43 long noncoding RNAs, observed 784 alternative splicing events and also found the occurrence of 8729 allele-specific expression sites and 122 RNA editing events. The expression profiles of the selected 16 phenomena were confirmed by PCR or qPCR techniques. As a final result of functional meta-analysis, we acquired knowledge regarding intracellular pathways that induce changes in the processes accompanying transcription and translation regulation, which may induce modifications in the secretory activity of the porcine adenohypophyseal cells.

PI(4,5)P2-dependent and -independent roles of PI4P in the control of hormone secretion by pituitary cells

Plasma membrane and organelle membranes are home to seven phosphoinositides, an important class of low-abundance anionic signaling lipids that contribute to cellular functions by recruiting cytoplasmic proteins or interacting with the cytoplasmic domains of membrane proteins. Here, we briefly review the functions of three phosphoinositides, PI4P, PI(4,5)P2, and PI(3,4,5)P3, in cellular signaling and exocytosis, focusing on hormone-producing pituitary cells. PI(4,5)P2, acting as a substrate for phospholipase C, plays a key role in the control of pituitary cell functions, including hormone synthesis and secretion. PI(4,5)P2 also acts as a substrate for class I PI3-kinases, leading to the generation of two intracellular messengers, PI(3,4,5)P3 and PI(3,4)P2, which act through their intracellular effectors, including Akt. PI(4,5)P2 can also influence the release of pituitary hormones acting as an intact lipid to regulate ion channel gating and concomitant calcium signaling, as well as the exocytic pathway. Recent findings also show that PI4P is not only a precursor of PI(4,5)P2, but also a key signaling molecule in many cell types, including pituitary cells, where it controls hormone secretion in a PI(4,5)P2-independent manner.

RC-4BC cells express nicotinic and muscarinic acetylcholine receptors

Acetylcholine is one of the most important endogenous neurotransmitters in a range of organisms spanning different animal phyla. Within pituitary gland it acts as autocrine and paracrine signal. In a current study we assessed expression profile of the different subunits of nicotinic as well as muscarinic acetylcholine receptors in RC-4BC cells, which are derived from rat pituitary gland tumor. Our findings indicate that β2, δ, and M2 subunits are expressed by the cells with the lowest Ct values compared to other tested subunits. The detected Ct values were 26.6±0.16, 27.95±0.5, and 28.8±0.25 for β2, δ, and M2 subunits, respectively.

Systematic Analysis of Neurotransmitter Receptors in Human Breast Cancer Reveals a Strong Association With Outcome and Uncovers HTR6 as a Survival-Associated Gene Potentially Regulating the Immune Microenvironment

Many epidemiological reports have indicated an increase in the incidence of breast cancer among psychotic patients, suggesting that the targets of antipsychotics, neurotransmitter receptors, may have a role in tumorigenesis. However, the functions of neurotransmitter receptors in cancer are barely known. Here, we analyzed 44 neurotransmitter receptors in breast cancer and revealed that the expression of 34 receptors was positively correlated with relapse-free survival rates (RFS) of patients using the public database (n = 3951). Among all these receptors, we revealed decreased expression of HTR6 in human advanced breast cancer versus tumors in situ using our original data (n = 44). After a pan-cancer analysis including 22 cancers (n = 11262), we disclosed that HTR6 was expressed in 12 tumors and uncovered its influence on survival in seven tumors. Using multi-omics datasets from Linkedomics, we revealed a potential regulatory role of HTR6 in MAPK, JUN, and leukocyte-differentiation pathways through enriching 294 co-expressed phosphorylated proteins of HTR6. Furthermore, we proclaimed a close association of HTR6 expression with the immune microenvironment. Finally, we uncovered two possible reasons for HTR6 down-regulation in breast cancer, including deep deletion in the genome and the up-regulation of FOXA1 in breast cancer, which was a potential negatively regulatory transcription factor of HTR6. Taken together, we revealed a new function of neurotransmitter receptors in breast cancer and identified HTR6 as a survival-related gene potentially regulating the immune microenvironment. The findings in our study would improve our understanding of the pathogenesis of breast cancer and provided a theoretical basis for personalized medication in psychotic patients.

Long-term stiripentol administration, an anticonvulsant drug, does not impair sperm parameters in rats

In this study, we investigated the influence of long-term administration of stiripentol on sex hormones and semen quality in young Wistar rats. Investigated animals received for 6 months either stiripentol or saline solution. After one month, stiripentol increased temporarily serum level of testosterone (p < 0.05) and FSH (p < 0.01). However, after 6 months levels of testosterone, FSH, LH, prolactin and SHBG were comparable in both groups. After 6 months, semen analysis did not reveal differences in sperm concentration, total sperm count and sperm motility between groups. However, stiripentol increased the rate of head defect (p < 0.001) and midpiece abnormalities (p < 0.05). Flow cytometry revealed higher percentage of live cells without lipid peroxidation (p < 0.00001) and higher percentage of live spermatozoa with intact acrosomes (p < 0.000001) in rats receiving stiripentol. There was no significant difference between groups in sperm mitochondrial activity and DNA fragmentation index. However, percentage of high DNA stainability cells was increased in stiripentol group (p < 0.001). The data showed that stiripentol does not cause obvious disturbances in young rat's semen. Detected changes in semen morphology and chromatin structure need further explanation, and their influence on rat's fertility should be evaluated.

The adverse effects of psychotropic drugs as an endocrine disrupting chemicals on the hypothalamic-pituitary regulation in male

Adverse effects of drugs on male reproductive system can be categorized as pre-testicular, testicular, and post-testicular. Pre-testicular adverse effects disrupt the hypothalamic-pituitary-gonadal (HPG) axis, generally by interfering with endocrine function. It is known that the HPG axis has roles in the maintenance of spermatogenesis and sexual function. The hypothalamus secretes gonadotropin-releasing hormone (GnRH) which enters the hypophyseal portal system to stimulate the anterior pituitary. The anterior pituitary secretes gonadotropins, follicle-stimulating hormone (FSH) and luteinizing hormone (LH) which are vital for spermatogenesis, into the blood. The FSH stimulates the Sertoli cells for the production of regulatory molecules and nutrients needed for the maintenance of spermatogenesis, while the LH stimulates the Leydig cells to produce and secrete testosterone. Many neurotransmitters influence the hypothalamic-pituitary regulation, consequently the HPG axis, and can consequently affect spermatogenesis and sexual function. Psychotropic drugs including antipsychotics, antidepressants, and mood stabilizers that all commonly modulate dopamine, serotonin, and GABA, can affect male spermatogenesis and sexual function by impairment of the hypothalamic-pituitary regulation, act like endocrine-disrupting chemicals. Otherwise, studies have shown the relationship between decreased sperm quality and psychotropic drugs treatment. Therefore, it is important to investigate the adverse reproductive effects of psychotropic drugs which are frequently used during reproductive ages in males and to determine the role of the hypothalamic-pituitary regulation axis on possible pathologies.

Electrochemical Nanocomposite Single-Use Sensor for Dopamine Detection

In this work, we report the development of a simple and sensitive sensor based on graphite screen-printed electrodes (GSPEs) modified by a nanocomposite film for dopamine (DA) detection. The sensor was realized by electrodepositing polyaniline (PANI) and gold nanoparticles (AuNPs) onto the graphite working electrode. The sensor surface was fully characterized by means of the cyclic voltammetry (CV) technique using [Fe(CN)6]4-/3- and [Ru(NH3)6]2+/3+ as redox probes. The electrochemical behavior of the nanocomposite sensor towards DA oxidation was assessed by differential pulse voltammetry (DPV) in phosphate buffer saline at physiological pH. The sensor response was found to be linearly related to DA concentration in the range 1-100 μM DA, with a limit of detection of 0.86 μM. The performance of the sensor in terms of reproducibility and selectivity was also studied. Finally, the sensor was successfully applied for a preliminary DA determination in human serum samples.

Propofol Requirement in Patients with Growth Hormone-Secreting Pituitary Tumors Undergoing Transsphenoidal Surgery

Growth hormone (GH) secretion is regulated by various hormones or neurotransmitters, including gamma-aminobutyric acid. The aim of this study was to determine the propofol requirement in patients with GH-secreting pituitary tumors undergoing transsphenoidal surgery. General anesthesia was induced in 60 patients with GH-secreting tumors (GH group, n = 30) or nonfunctioning pituitary tumors (NF group, n = 30) using an effect-site target-controlled intravenous propofol infusion. The effect-site concentrations were recorded at both a loss of consciousness and a bispectral index (BIS) of 40, along with the effect-site concentration after extubation, during emergence from the anesthesia. The effect-site concentration of propofol was higher in the GH group than in the NF group at a loss of consciousness and a BIS of 40 (4.09 ± 0.81 vs. 3.58 ± 0.67, p = 0.009 and 6.23 ± 1.29 vs. 5.50 ± 1.13, p = 0.025, respectively) and immediately after extubation (1.60 ± 0.27 vs. 1.40 ± 0.41, p = 0.046). The total doses of propofol and remifentanil during anesthesia were comparable between the groups (127.56 ± 29.25 vs. 108.64 ± 43.16 µg/kg/min, p = 0.052 and 6.67 ± 2.89 vs. 7.05 ± 1.96 µg/kg/h, p = 0.550, respectively). The propofol requirement for the induction of a loss of consciousness and the achievement of a BIS of 40 is increased during the induction of general anesthesia in patients with GH-secreting tumors.