Gene expression profile of hiPSC-derived cells differentiated with growth factors, forskolin and conditioned medium from human adrenocortical cell line

BACKGROUND

Adrenocortical carcinoma (ACC) affects approx. 2 in 1,000,000 individuals in the USA, and is more common in females than males. Adrenocortical carcinoma often presents with severe symptoms, such as abdominal pain, high blood pressure, acne, hair overgrowth, and voice deepening.

OBJECTIVES

Research on ACC constitutes a large body of published data. There is an increased need for easy access to ACC-derived biological material. Moreover, there are limited numbers of human cell lines available. For this reason, we attempted to differentiate human induced pluripotent stem cells (hiPSCs) into adrenocortical-like cells to establish a new functional cell line.

MATERIAL AND METHODS

We conducted a long-term differentiation process (35 and 70 days) in the presence of growth factors (GFs), forskolin and conditioned medium collected from the human adrenal carcinoma (HAC15) cell line. Then, we analyzed the gene expression profile of the differentiated cells.

RESULTS

The obtained cells possess features characteristic of all 3 primary germ layers. Interestingly, the differentiated cells demonstrated an extremely high level of gene expression for those involved in endocrine processes, namely glycoprotein hormones, alpha polypeptide (CGA), insulin receptor substrate 4 (IRS4), and pancreatic progenitor cell differentiation and proliferation factor-like protein (PPDPFL).

CONCLUSIONS

The results of the study indicate that we obtained progenitors derived from endoderm with some characteristics of pancreatic-like cells. The endodermal derivative differentiation is a very challenging and complicated process; thus, the results presented in this study deserve closer consideration.

Impaired Expression of Humanin during Adrenocortical Carcinoma

The discovery of mitochondria-derived peptides (MDPs) has provided a new perspective on mitochondrial function. MDPs encoded by mitochondrial DNA (mtDNA) can act as hormone-like peptides, influencing cell survival and proliferation. Among these peptides, humanin has been identified as a crucial factor for maintaining cell survival and preventing cell death under various conditions. Adrenocortical carcinoma (ACC) is a rare and aggressive malignancy that results from adrenal hormone dysfunction. This study aimed to investigate humanin expression in the adrenal tissue and serum of patients with ACC. For the first time, our study revealed significant reduction in the mRNA expression of humanin in patients with ACC compared to healthy controls. However, no significant changes were observed in the serum humanin levels. Interestingly, we identified a positive correlation between patient age and serum humanin levels and a negative correlation between tumor size and LDL levels. While the impaired expression of humanin in patients with ACC may be attributed to mitochondrial dysfunction, an alternative explanation could be related to diminished mitochondrial copy number. Further investigations are warranted to elucidate the intricate relationship among humanin, mitochondrial function, and ACC pathology.

Impact of Classic Adrenal Secretagogues on mRNA Levels of Urotensin II and Its Receptor in Adrenal Gland of Rats

Urotensin 2 (Uts2) is a biologically active peptide involved in the regulation of a variety of physiological and pathophysiological processes. In both the human and rat adrenal gland, the expressions of the Uts2 gene and its receptor (Uts2r) have been described. This paper focuses on the description of the hormonal control of the mRNA levels of urotensin II and its receptor in the adrenal gland of the rat, both in vitro and in vivo. The initial in vitro experiments were carried out on freshly isolated rat adrenocortical cells and their primary culture. The obtained results indicated a stimulating PKA-independent effect of ACTH on the Uts2 mRNA level in the tested cells, with no changes in the Uts2r transcript. Subsequent in vivo experiments showed that ACTH-induced adrenal growth was accompanied by an elevated level of the Uts2 mRNA, with unchanged expression of Uts2r. In the other types of in vivo gland growth studied, enucleation-induced adrenal regeneration and compensatory growth of the gland, the mRNA levels of the studied genes showed no significant differences. The only exception was hemiadrenalectomy, which led to a significant increase in Uts2 mRNA expression level 24 h after surgery. In 12-week-old rats of both sexes, gonadectomy led to a significant increase in the level of Uts2 mRNA in the adrenal gland, an effect that was prevented by sex hormones' replacement. No changes in Uts2r transcript levels were observed under these conditions. Thus, this study suggests that the regulation of Uts2 and Uts2r mRNA levels differs significantly in the rat adrenal gland. While Uts2 transcript levels appear to be mainly dependent on ACTH action, Uts2r mRNA levels are not under the control of this hormone.

Transcriptome Profile of the Rat Adrenal Gland: Parenchymal and Interstitial Cells

The homeostasis of the adrenal gland plays a decisive role in its proper functioning, both in non-stressful conditions and under the influence of various types of stress. This consists of interactions between all types of cells that make up the organ, including parenchymal and interstitial cells. The amount of available information on this subject in the rat adrenal glands under non-stressful conditions is insufficient; the aim of the research was to determine the expression of marker genes for rat adrenal cells depending on their location. The material for the study consisted of adrenal glands taken from intact adult male rats that were separated into appropriate zones. Transcriptome analysis by means of Affymetrix^® Rat Gene 2.1 ST Array was used in the study, followed by real-time PCR validation. Expression analysis of interstitial cell marker genes revealed both the amount of expression of these genes and the zone in which they were expressed. The expression of marker genes for fibroblasts was particularly high in the cells of the ZG zone, while the highest expression of specific macrophage genes was observed in the adrenal medulla. The results of this study, especially with regard to interstitial cells, provide a so far undescribed model of marker gene expression of various cells, both in the cortex and medulla of the sexually mature rat adrenal gland. The interdependence between parenchymal and interstitial cells creates a specific microenvironment that is highly heterogeneous within the gland with respect to some of the interstitial cells. This phenomenon most likely depends on the interaction with the differentiated parenchymal cells of the cortex, as well as the medulla of the gland.

The Enhanced Expression of ZWILCH Predicts Poor Survival of Adrenocortical Carcinoma Patients

Zwilch kinetochore protein (ZWILCH) plays a key role in proper cell proliferation. The upregulation of the ZWILCH gene was observed in many types of cancers, but the association of ZWILCH with adrenocortical carcinoma (ACC) was not investigated so far. The main aim of the presented study was to verify if the enhanced level of the ZWILCH gene can be used as a diagnostic marker for ACC development and progression, as well as a predictor of survival time for ACC patients. The performed analyses included investigation of the ZWILCH expression profile in tumors with publicly available TCGA (The Cancer Genome Atlas) datasets and transcriptomic data from the Gene Expression Omnibus (GEO) database, as well as, in human biological samples of normal adrenal, adrenocortical carcinoma and in commercially available tissue microarrays. The findings demonstrate statistically significant higher ZWILCH gene expression in ACC tissue in comparison with normal adrenal glands. Furthermore, there is a strong correlation between ZWILCH upregulation and tumor mitotic rate and the probability of patient survival. The enhanced ZWILCH level is also connected with the activation of genes involved in cell proliferation and the inhibition of genes related to the immune system. This work contributes to a better understanding of the role of ZWILCH as an ACC biomarker and diagnostic tool.

Effects of Galp and alarin peptides on HPA axis gene expression and adrenal function: In vivo experiments

BACKGROUND

Many experimental data indicate interactions between peptides involved in the control of food intake, energy homeostasis and adrenocortical hormone release. Glucocorticoids stimulate or inhibit the secretion of orexigenic and anorexigenic peptides, which in turn are involved in the regulation of adrenal growth, structure and function. Galanin-like peptide (Galp) and alarin (Ala) are involved in the regulation of food intake. Galp and Ala mRNAs have already been shown to be present in the arcuate nucleus (ARC) of the hypothalamus in both rats and mice.

OBJECTIVES

To investigate the expression of Ala, Galp and their receptors in the hypothalamus and pituitary and adrenal glands of the rat hypothalamic-pituitary-adrenal (HPA) axis after intraperitoneal administration of peptides in vivo.

MATERIAL AND METHODS

Experimental in vivo models were used: acute and long-term exposure to peptides.

RESULTS

The expression of Galp, Ala, their receptors, and steroidogenesis enzymes was analyzed using quantitative real-time polymerase chain reaction (qRT-PCR). Statistically significant expression changes were found in the hypothalamus and pituitary after 1-hour exposure to the peptides, such as a decrease in corticotropin-releasing hormone (CRH) expression after Ala, Galp and adrenocorticotropic hormone (ACTH) administration, and a decrease in the expression of receptors for galanin (Gal) (Galr1 and Galr2). In the pituitary, there was a statistically significant increase in the expression of Ala, Galr1, Galr2, and Galr3 receptors 1 h after Galp administration. In the adrenal glands, only a statistically significant decrease in Galr2 expression was observed after 1 h of Ala 0.5 administration. The mRNA expression of steroidogenesis enzymes also changed: for example, the expression of cholesterol desmolase increased 24 h after Ala peptide administration.

CONCLUSIONS

The results indicate that the peptides tested under in vivo conditions can alter the expression of the peptides tested, as well as of Galp, Ala and Gal receptors and steroidogenesis enzymes - Cyp11a1 (cholesterol desmolase), Cyp11b1 (11β-hydroxylase) and Cyp11b2 (aldosterone synthase).

Extracellular Nampt (eNampt/visfatin/PBEF) directly and indirectly stimulates ACTH and CCL2 protein secretion from isolated rat corticotropes

BACKGROUND

Nicotinamide phosphoribosyltransferase (Nampt/visfatin/PBEF) acts both as an enzyme in the nicotinamide adenine dinucleotide (NAD) synthesis pathway as well as an extracellular hormone (eNampt). Among its effects, eNampt exerts potent pro-inflammatory effects. We have recently shown that, in rats, eNampt stimulates corticosterone secretion by acting through the pituitary rather than the hypothalamus.

OBJECTIVES

To investigate the mechanism of action of eNampt on the secretion of adrenocorticotropic hormone (ACTH) and chemokine (C-C motif) ligand 2 (CCL2), which are cytokines secreted by pituitary neuroendocrine tumors.

MATERIAL AND METHODS

The research was carried out on the AtT-20 murine cell line, primary rat pituitary cell culture, isolated pituitary corticotropes, and in vivo. The effects of the performed experiments were examined using the following methods: gene expression profiling using microarrays, quantitative polymerase chain reaction (qPCR) and enzyme-linked immunosorbent assay (ELISA).

RESULTS

The results suggest that eNampt stimulates ACTH secretion from rat corticotropes both directly and indirectly. Indirect action most likely occurs through interleukin (IL)-6 secreted by folliculostellate cells of the pituitary gland. In isolated ACTH cells of the rat pituitary gland, eNampt stimulates the expression of genes involved in the immune response. Among them, the protein encoded by the CCL2 gene seems to also be involved in the regulation of corticotropin-releasing hormone (CRH)-dependent metabolism. Unlike rat corticotropes, murine AtT-20 corticotropic cells do not react to either eNampt or Fk866 (the inhibitor of Nampt enzymatic action).

CONCLUSIONS

The eNampt stimulates the secretion of ACTH from rat corticotropes indirectly and directly, likely by stimulating IL-6 secretion from folliculostellate cells of the pituitary gland. This effect was not observed in the AtT-20 corticotropic cell cancer cell line.

Adropin Stimulates Proliferation and Inhibits Adrenocortical Steroidogenesis in the Human Adrenal Carcinoma (HAC15) Cell Line

Adropin is a multifunctional peptide hormone encoded by the ENHO (energy homeostasis associated) gene. It plays a role in mechanisms related to increased adiposity, insulin resistance, as well as glucose, and lipid metabolism. The low adropin levels are strongly associated with obesity independent insulin resistance. On the other hand, overexpression or exogenous administration of adropin improves glucose homeostasis. The multidirectional, adropin-related effects associated with the regulation of metabolism in humans also appear to be attributable to the effects of this peptide on the activity of various elements of the endocrine system including adrenal cortex. Therefore, the main purpose of the present study was to investigate the effect of adropin on proliferation and secretory activity in the human HAC15 adrenal carcinoma cell line. In this study, we obtained several highly interesting findings. First, GPR19, the main candidate sensitizer of adrenocortical cells to adropin, was expressed in HAC15 cells. Moreover, GPR19 expression was relatively stable and not regulated by ACTH, forskolin, or adropin itself. Our findings also suggest that adropin has the capacity to decrease expression levels of steroidogenic genes such as steroidogenic acute regulatory protein (StAR) and CYP11A1, which then led to a statistically significant inhibition in cortisol and aldosterone biosynthesis and secretion. Based on whole transcriptome study and research involving transforming growth factor (TGF)-β type I receptor kinase inhibitor we demonstrated that attenuation of steroidogenesis caused by adropin is mediated by the TGF-β signaling pathway likely to act through transactivation mechanism. We found that HAC15 cells treated with adropin presented significantly higher proliferation levels than untreated cells. Using specific intracellular inhibitors, we showed that adropin stimulate proliferation via ERK1/2 and AKT dependent signaling pathways. We have also demonstrated that expression of GPR19 is elevated in adrenocortical carcinoma in relation to normal adrenal glands. High level of GPR19 expression in adrenocortical carcinoma may constitute a negative prognostic factor of disease progression.

Expression profile of Galp, alarin and their receptors in rat adrenal gland

BACKGROUND

Galanin-like peptide (Galp) and alarin (Ala) are 2 new members of the galanin peptide family. Galanin (Gal), the "parental" peptide of the entire family, is known to regulate numerous physiological processes, including energy and osmotic homeostasis, reproduction, food intake, and secretion of adrenocortical hormones. Galp and Ala are known to regulate food intake. In the rat, Galp mRNA has been found in the brain, exclusively in the hypothalamic arcuate nucleus (ARC) and median eminence, which are involved in the regulation of energy homeostasis. Alarin-like immunoreactivity is present in the locus coeruleus (LC) and the ARC of rats and mice.

OBJECTIVES

The aim of the study was to investigate the expression of Ala, Galp and their receptors in the organs of the hypothalamo-pituitary-adrenal (HPA) axis of the rat.

MATERIAL AND METHODS

The expression of the examined genes was measured in different models of adrenal growth of the rat in vivo (postnatal ontogenesis, compensatory adrenal growth, adrenocortical regeneration, adrenocorticotropic hormone (ACTH) administration). The expression was evaluated using the Affymetrix® microarray system or quantitative polymerase chain reaction (qPCR).

RESULTS

The expression of Ala gene was observed in each organ of the HPA axis (the hypothalamus, hypophysis and adrenal gland). The elevated level of expression of this gene was observed in the pituitary of 2-day rats, while very low levels of Ala mRNA were observed in the adrenals. Galp mRNA expression was observed only in the hypothalamus and the hypophysis during postnatal ontogenesis. The expression of Gal receptors was demonstrated in the hypothalamus, the hypophysis and the adrenal gland. In different compartments of the adrenal glands of adult, intact male and female rats, the expression of Ala, Galp and galanin receptor 1 (Galr1) genes was negligible, but the expression of galanin receptor 2 (Galr2), galanin receptor 3 (Galr3) and neurotrophic receptor tyrosine kinase 2 (Ntrk2) genes was noticeable.

CONCLUSIONS

The examined genes showed different expression levels within the studied HPA axis; some of them were neither expressed in the hypothalamus or the pituitary gland, nor in the adrenal gland.

ZFP91 zinc finger protein expression pattern in normal tissues and cancers

Zinc finger protein 91 (ZFP91) gene has been recently acknowledged to possess oncogenic properties. To date, its expression has been examined only in a handful of human organs and cancer types. The aim of the present study was to characterize, for the first time, the ZFP91 expression pattern in a range of human tissues and cancer types. ZFP91 mRNA expression was examined using Cancer Survey cDNA sets. Utilized cDNA samples represented 15 human organs and 17 cancer types. ZFP91 mRNA expression was the highest in the testes and lymph nodes. It was downregulated in testis cancer, lymphoma and thyroid cancer, and upregulated in prostate cancer. Among the analyzed cancer types, ZFP91 expression was markedly elevated in sarcomas and melanoma. On a protein level, a large-scale reverse phase protein array was employed providing samples from 11 organ types and from cancers derived from these organs. ZFP91 protein expression was revealed to be generally stable across the tested samples and was only moderately elevated in breast, ovarian and pancreatic cancers. To the best of our knowledge, this is the first study to thoroughly analyze the ZFP91 expression pattern in human tissues and cancers. The obtained results provide the foundation for further work aiming to reveal its full biological significance.

Ghrelin as a potential molecular marker of adrenal carcinogenesis: In vivo and in vitro evidence

CONTEXT

Adrenal tumours belong to one of the most prevalent neoplasms. It is a heterogeneous group with different aetiology, clinical manifestation and prognosis. Its histopathologic diagnosis is difficult and identification of differentiation markers for tumorigenesis is extremely valuable for diagnosis.

DESIGN

To assess ghrelin expression and the relationship among ghrelin, IGF2 and the clinicopathological characteristics of adrenal tumours. To investigate the influence of ghrelin on ACC cell line proliferation.

MATERIALS AND METHODS

Expression of ghrelin and IGF2 in a total of 84 adrenal tissue samples (30 adenoma, 12 hyperplasia, 8 myelolipoma, 20 pheochromocytoma, 7 carcinoma and 7 unchanged adrenal glands) were estimated. Every operated patient from whom samples were obtained underwent clinicopathological analysis. All the parameters were compared among the groups examined and correlations between these were estimated. H295R cell line was incubated with ghrelin to assess its effect on proliferation and migration rate.

RESULTS

The highest ghrelin expression was observed in carcinoma samples and the lowest in the control group. Ghrelin expression was 21 times higher in carcinoma (P = .017) and 2.4 times higher in adenoma (P = .029) compared with controls. There were no statistically significant differences between myelolipoma (P = .093) and pheochromocytoma (P = .204) relative to the control. Ghrelin level was significantly higher in carcinoma compared to adenoma (P = .049) samples. A positive correlation between ghrelin and IGF2 expression was observed only in myelolipoma (P = .001). Ghrelin at concentrations of 1 × 10^-6  mol/L and 1 × 10^-8  mol/L significantly stimulated proliferation and migration rate in the H295R cell line.

CONCLUSION

Ghrelin appears to be an essential factor in driving adrenal tumours development.

Nicotinamide phosphoribosyltransferase and the hypothalamic-pituitary-adrenal axis of the rat

Nicotinamide phosphoribosyltransferase (Nampt), also termed visfatin, catalyses the rate‑limiting step in the nicotinamide adenine dinucleotide (NAD) salvage pathway. In addition to its intracellular function (iNampt), extracellular Nampt (eNampt) also affects numerous intracellular signalling pathways. The current study investigated the role of Nampt in the regulation of the hypothalamic‑pituitary‑adrenal (HPA) axis in rats. At 1 h after intraperitoneal administration of eNampt (4 µg/100 g) in adult male rats, serum adrenocorticotropic hormone(ACTH) and aldosterone levels remained unchanged, while corticosterone levels were notably elevated compared with the control group, as determined by ELISA. The results of reverse transcription‑quantitative polymerase chain reaction (RT‑qPCR) demonstrated that, in the hypothalami of eNampt‑treated rats, the mRNA expression levels of Fos proto‑oncogene, which is also termed c‑Fos, were not significantly different compared with the control group; however, the mRNA expression levels of proopiomelanocortin (POMC) were markedly increased in the pituitary gland of eNampt‑treated rats compared with the control group. Furthermore, in hypothalamic explants, ELISA results demonstrated that the addition of the eNampt protein exhibited no effect on corticotropin‑releasing hormone (CRH) release into the incubation medium and prevented potassium ion‑induced CRH release. Additionally, the eNampt‑induced increase in ACTH output by pituitary gland explants was not statistically significant, compared with the control group. However, RT‑qPCR indicated that exposure of pituitary gland explants to eNampt and CRH increased the levels of POMC mRNA expression; the effect of eNampt, but not CRH, was inhibited by FK866, which is a specific Nampt inhibitor. In primary rat adrenocortical cell cultures, eNampt exhibited no effect on basal aldosterone or corticosterone secretion, while increases in aldosterone and corticosterone levels in response to ACTH were retained. To assess the potential role of iNampt in the regulation of adrenal steroidogenesis, experiments involving a specific Nampt inhibitor, FK866, were performed. Exposure of cultured cells to FK866 notably lowered basal aldosterone and corticosterone output compared with the control group, and completely eliminated the response of cultured cells to ACTH. The results of the present study indicated that the injected eNampt may have increased the corticosterone serum levels by acting at the pituitary level. In addition, iNampt may exert a tonic stimulating effect on the secretion of aldosterone and corticosterone from rat adrenocortical cells, as normal iNampt levels were required to retain the response of cultured rat adrenocortical cells to ACTH. Thus, these data suggest an important physiological role of both iNampt and eNampt in the regulation of the HPA axis activity in the rat.

Mitochondrial sirtuins in the rat adrenal gland: location within the glands of males and females, hormonal and developmental regulation of gene expressions

INTRODUCTION

Sirtuins are NAD dependent class III histone deacetylases. In adrenal cortex mitochondria are able to transform - via nicotinamide nucleotide transhydrogenase (NNT) - NAD into NADPH, which is required for steroidogenesis. These findings suggest that sirtuins expressed in mitochondria, Sirt3, Sirt4 and Sirt5, may be associated with adrenal steroidogenesis. Therefore, the purpose of this study was to characterize the expression of mitochondrial sirtuins (Sirt3-5) in individual compartments of rat adrenal cortex, their developmental regulation and to demonstrate whether their expression is dependent on adrenocorticotrophic hormone (ACTH) and Nampt (nicotinamide phosphoribosyltransferase also known as visfatin/PBEF), the rate-limiting enzyme in the regulation of mammalian NAD synthesis.

MATERIAL AND METHODS

Studies were performed on rat adrenal glands or on primary culture of rat adrenocortical cells. Expression of mitochondrial sirtuins (Sirt3-5) was evaluated by Affymetrix microarray system or QPCR. The bulk of data were extracted from our earlier experiments which have been reanalyzed in regard to Sirt3-5 mRNAs expression levels and - if necessary - validated by QPCR.

RESULTS

Sirt3-5 were expressed throughout the rat adrenal, with the highest expression level of Sirt5. The level of expression of all sirtuins is higher in the zona glomerulosa (ZG) and zona fasciculata/reticularis (ZF/R) than in the adrenal medulla. Sirt3 and Sirt5 expression levels were similar in adult male and female rats, while Sirt4 expression level was higher in females. As revealed by analysis of the available open database, no significant changes in Sirt3-5 expression levels in whole adrenal glands were observed up to week 104 of life of both male and female rats. Moreover, 60 min after intraperitoneal ACTH injection the expression level of Sirt3 in the en-tire gland was elevated while Sirt5 expression level lowered. On the other hand, chronic ACTH infusion (48 h) did not change expression of studied sirtuins. In cultured cells, ACTH greatly increased the expression levels of the Sirt4 and Sirt5. In cultured cells, Fk866 - a highly specific competitive inhibitor of Nampt - reduced expression level of Sirt5 only. In enucleation-induced regenerating rat adrenal, the expression levels of all studied sirtuins were significantly reduced in relation to the control group. Finally, in primary rat adrenal culture the FCS depletion elevates the Sirt3 and Sirt4 expression levels and downregulates Sirt5 expression.

CONCLUSIONS

Sirt3-5 are expressed throughout the rat adrenal, with the highest expression levels in adrenal cortex. Performed experiments (ACTH stimulation, FCS depletion, regeneration) suggest that in the adrenal cortex, the mitochondrial Sirt5 is the primary mitochondrial sirtuin involved in regulating the biological activity of adrenocortical cells. Our results also suggest that normal levels of intracellular Nampt (iNampt) enzymatic activity are required to maintain normal (control) levels of Sirt5 mRNA in cultured cells.

Effects of leptin on leptin receptor isoform expression and proliferative activity in human normal prostate and prostate cancer cell lines

Results of studies on the expression of leptin and its receptors in the human prostate gland and human prostate cell lines are contradictory. Regarding this, we carefully reinvestigated this issue using human normal prostate (PrEC, PrSC, PrSMC) and prostate cancer (DU145, LNCaP, PC3) cell lines. Expression of leptin receptor isoforms was assessed by qPCR while the effects of leptin on cell proliferative activity was determined by real-time cell analyzer (RTCA). Expression of the leptin receptor variant 1 was not detected in LNCaP and PrSMC cell lines, but it was found in the remaining cell lines. In contrast, in all examined cell lines, isoforms 1-3 and 2 and 4 of the leptin receptor were found. The expression of isoforms 3 and 6 of the leptin receptor was observed in PC3, PrEC, PrSMC and PrSC cell lines, but not in LNCaP and DU145 cells. Expression of the leptin receptor isoforms 4-6 and 5 was not demonstrated in any of the tested cell lines. We also studied the effects of leptin on the expression of its receptor isoforms in all tested cell lines. At a wide range of concentrations, leptin did not change the expression of leptin receptor variant 1 in the DU145, PrEC and PC3 cell lines. In contrast, in the PrSC cell line, leptin significantly increased the expression of this gene. In all prostate cell lines tested, leptin did not alter the expression levels of variants 1-3 of the leptin receptor isoforms. Leptin did not alter the expression of isoforms 2 and 4 of the leptin receptor in the PC3 and LNCaP cell lines. In the DU145 and PrEC cell lines, leptin inhibited expression of these receptor isoforms while an opposite effect was noted in the PrSC cells. Leptin did not affect the expression level of variants 3 and 6 of its receptor in the PrEC and PC3 cell lines. However, in PrSMC cells, leptin inhibited the expression of variants 3 and 6 of its receptor, while in the PrSC cell line this cytokine significantly increased their expression levels. As assessed by RTCA, leptin stimulated the proliferative activity of DU145 cells, but inhibited this activity in LNCaP cells. At all concentrations tested, leptin did not change the proliferation rate of the PC3, PrEC and PrSMC cells. In contrast, leptin notably stimulated the proliferative activity of the PrSC (prostate stromal cell) cell line. Thus, our study demonstrated that in all tested human normal prostate and prostate cancer cell lines, transcription variants 4, 5 and 6 of the leptin receptor were not expressed. Leptin receptor transcription variants 1, 2 and 3 showed differential expression, which was present in the PC3, PrEC and PrSC cell lines. Our data also suggest that the stimulatory effects of leptin on proliferative activity of the studied cell lines require the expression of leptin receptor variant 1 in the affected cells.

Transcriptome Profile of Rat Adrenal Evoked by Gonadectomy and Testosterone or Estradiol Replacement

Sex differences in adrenal cortex structure and function are well known in different species. In the rat, they are manifested as larger adrenal cortex and higher corticosterone secretion by females compared with males. These sex differences depend, among others, on functioning of the hypothalamic-pituitary-adrenal axis (HPA). In this aspect, it is widely accepted that testosterone exerts an inhibitory and estradiol stimulatory effect on the said axis. The molecular bases of these sex-related differences are poorly understood. Therefore, we performed studies aimed to demonstrate the effect of testosterone and estradiol on the expression of differentially regulated genes in rat adrenal gland. The classical method applied in the study-gonadectomy and gonadal hormone replacement-allows obtaining results suggesting a physiological role of the tested hormone (testosterone or estradiol) in the regulation of the specific genes. Adult male and female rats were either gonadectomized or sham operated. Half of orchiectomized rats were replaced with testosterone while ovariectomized ones with estradiol. Transcriptome was identified by means of Affymetrix^® Rat Gene 2.1 ST Array. Differentially expressed genes were analyzed by means of DAVID web-based bioinformatic tools and confirmed by means of Gene Set Enrichment Analysis. For selected genes, validation of the results was performed using QPCR. Performed experiments have provided unexpected results. Contrary to expectations, in orchiectomized rats, testosterone replacement stimulates expression of numerous genes, mainly those associated with lipids and cholesterol metabolism. However, in ovariectomized animals, estradiol replacement inhibits the expression of genes, mainly those involved in intracellular signaling pathways. The physiological relevance of these findings awaits further research.

Lack of expression of preproorexin and orexin receptors genes in human normal and prostate cancer cell lines

INTRODUCTION

Studies on expression of orexins (OXs) and their receptors in human prostate gland and human prostatic cell lines are scanty and their results contradictory. Regarding this, we carefully reinvestigated this problem on human prostatic cell lines.

MATERIAL AND METHODS

Expression of preproorexin (ppOX) (6 primer pairs), and orexin receptors 1 and 2 (OXR1, OXR2) (4 and 2 primer pairs, respectively) was assessed by conventional PCR and QPCR in human normal (PrEC, PrSc, PrSmC) and prostate carcinoma (Du145, LNCaP, and PC3) cell lines. We designed intron spanning primers and also we applied primers from earlier publications and commercially available ones.

RESULTS

With the designed primer pairs, in all studied cell lines we failed to demonstrate expression of ppOX, OXR1 and OXR2 genes at the mRNA level, while reaction products were observed in control tissues (human placenta and adrenals). Primers applied in earlier studies did not form amplification products specific for preproorexin or orexin 1 receptor. Some commercially available primers for orexin receptor 1 produced false positive results.

CONCLUSIONS

We found no evidence for the presence of preproorexin-orexin receptors system genes' mRNAs in human prostate cell lines. The reported premises for these genes’ expression in prostate and prostatic cell lines may have arisen either from the presence of non-prostate cells included in the samples or from faulty PCR settings.

Sex-related gene expression profiles in the adrenal cortex in the mature rat: microarray analysis with emphasis on genes involved in steroidogenesis

Notable sex-related differences exist in mammalian adrenal cortex structure and function. In adult rats, the adrenal weight and the average volume of zona fasciculata cells of females are larger and secrete greater amounts of corticosterone than those of males. The molecular bases of these sex-related differences are poorly understood. In this study, to explore the molecular background of these differences, we defined zone- and sex-specific transcripts in adult male and female (estrous cycle phase) rats. Twelve-week-old rats of both genders were used and samples were taken from the zona glomerulosa (ZG) and zona fasciculata/reticularis (ZF/R) zones. Transcriptome identification was carried out using the Affymetrix^® Rat Gene 1.1 ST Array. The microarray data were compared by fold change with significance according to moderated t-statistics. Subsequently, we performed functional annotation clustering using the Gene Ontology (GO) and Database for Annotation, Visualization and Integrated Discovery (DAVID). In the first step, we explored differentially expressed transcripts in the adrenal ZG and ZF/R. The number of differentially expressed transcripts was notably higher in the female than in the male rats (702 vs. 571). The differentially expressed genes which were significantly enriched included genes involved in steroid hormone metabolism, and their expression levels in the ZF/R of adult female rats were significantly higher compared with those in the male rats. In the female ZF/R, when compared with that of the males, prevailing numbers of genes linked to cell fraction, oxidation/reduction processes, response to nutrients and to extracellular stimuli or steroid hormone stimuli were downregulated. The microarray data for key genes involved directly in steroidogenesis were confirmed by qPCR. Thus, when compared with that of the males, in the female ZF/R, higher expression levels of genes involved directly in steroid hormone synthesis were accompanied by lower expression levels of genes regulating basal cell functions.

Visinin-like peptide 1 in adrenal gland of the rat. Gene expression and its hormonal control

VSNL1 encodes the calcium-sensor protein visinin-like 1 and was identified previously as an upregulated gene in a sample set of aldosterone-producing adenomas. Recently, by means of microarray studies we demonstrated high expression of Vsnl1 gene in rat adrenal zona glomerulosa (ZG). Only scanty data are available on the role of this gene in adrenal function as well as on regulation of its expression by factors affecting adrenal cortex structure and function. Therefore we performed relevant studies aimed at clarifying some of the above issues. By Affymetrix(®) Rat Gene 1.1 ST Array Strip, QPCR and immunohistochemistry we demonstrated that expression levels of Vsnl1 in the rat adrenal ZG are notably higher than in the fasciculata/reticularis zone. In QPCR assay this difference was approximately 10 times higher. Expression of this gene in the rat adrenal gland or adrenocortical cells was acutely down regulated by ACTH, while chronic administration of corticotrophin or dexamethasone did not change Vsnl1 mRNA levels. In enucleation-induced adrenocortical regeneration expression levels of both Vsnl1 and Cyp11b2 were notably lowered and positively correlated. Despite these findings, the physiological significance of adrenal Vsnl1 remains unclear, and requires further investigation.

Enucleation-induced rat adrenal gland regeneration: expression profile of selected genes involved in control of adrenocortical cell proliferation

Enucleation-induced adrenal regeneration is a highly controlled process; however, only some elements involved in this process have been recognized. Therefore, we performed studies on regenerating rat adrenals. Microarray RNA analysis and QPCR revealed that enucleation resulted in a rapid elevation of expression of genes involved in response to wounding, defense response, and in immunological processes. Factors encoded by these genes obscure possible priming effects of various cytokines on initiation of regeneration. In regenerating adrenals we identified over 100 up- or downregulated genes involved in adrenocortical cell proliferation. The changes were most significant at days 2-3 after enucleation and their number decreased during regeneration. For example, expression analysis revealed a notable upregulation of the growth arrest gene, Gadd45, only 24 hours after surgery while expression of cyclin B1 and Cdk1 genes was notably elevated between days 1-8 of regeneration. These changes were accompanied by changes in expression levels of numerous growth factors and immediate-early transcription factors genes. Despite notable differences in mechanisms of adrenal and liver regeneration, in regenerating adrenals we identified genes, the expression of which is well recognized in regenerating liver. Thus, it seems legitimate to suggest that, in the rat, the general model of liver and adrenal regeneration demonstrate some degree of similarity.

Expression of selected genes involved in steroidogenesis in the course of enucleation-induced rat adrenal regeneration

The enucleation-induced (EI) rapid proliferation of adrenocortical cells is followed by their differentiation, the degree of which may be characterized by the expression of genes directly and indirectly involved in steroid hormone biosynthesis. In this study, out of 30,000 transcripts of genes identified by means of Affymetrix Rat Gene 1.1 ST Array, we aimed to select genes (either up- or downregulated) involved in steroidogenesis in the course of enucleation-induced adrenal regeneration. On day 1, we found 32 genes with altered expression levels, 15 were upregulated and 17 were downregulated [i.e., 3β-hydroxysteroid dehydrogenase (Hsd3β), nuclear receptor subfamily 0, group B, member 1 (Nr0b1), cytochrome P450 aldosterone synthase (Cyp11b2) and sterol O-acyltransferase 1 (Soat1)]. On day 15, the expression of only 2 genes was increased and that of 3 was decreased. The investigated genes were clustered according to an hierarchical clustering algorithm and 4 clusters were obtained. Quantitative PCR (qPCR) confirmed the much lower mRNA expression levels of steroidogenic acute regulatory protein (StAR) during the regeneration process compared to the control, while the cholesterol side-chain cleavage enzyme (cholesterol desmolase; Cyp11a1) and Hsd3β genes presented similar expression profiles throughout the entire regeneration process. Cyp11b2 mRNA levels remained very low during the whole regeneration period. Fatty acid binding protein 6 (Fabp6) was markedly upregulated, whereas hormone-sensitive lipase (Lipe) was downregulated. The expression of Soat1 was lowest on regeneration day 1 and, subsequently, its expression increased from there on, reaching levels higher than the control. Dosage-sensitive sex reversal, adrenal hypoplasia critical region, on chromosome X, gene 1 (Dax-1) mRNA levels were lowest on day 1 of the experiment; however, throughout the entire experimental period, there were no statistically significant differences observed. After the initial decrease in steroidogenic factor 1 (Sf-1) mRNA levels observed on the 1st day of the experiment, a marked upregulation in its expression was observed from there on. Data from the current study strongly suggest the role of Fabp6, Lipe and Soat1 in supplying substrates of regenerating adrenocortical cells for steroid synthesis. Our results indicate that during the first days of adrenal regeneration, intense synthesis of cholesterol may occur, which is then followed by its conversion into cholesteryl esters. Moreover, our data demonstrated that in enucleation-induced regeneration, the restoration of genes involved in glucocorticoid synthesis is notably shorter than that of those involved in aldosterone synthesis.

Angiogenesis in the course of enucleation-induced adrenal regeneration--expression of selected genes and proteins involved in development of capillaries

Enucleation-induced rapid proliferation of adrenocortical cells and restoration of adrenals structure requires formation of new blood vessels. The performed studies aimed to select from around 30,000 transcripts, identified by means of Affymetrix(®) Rat Gene 1.1 ST Array, the genes involved in angiogenesis in the course of enucleation-induced adrenal regeneration and to characterize their expression levels in regenerating gland between days 1 and 15 after surgery. At day 1 of regeneration almost 2000 genes showed more than 2-fold up/down-regulation. At days 1-3 after surgery the highest expression demonstrated genes involved in the development of inflammation and blood clot formation. From around 2000 genes we selected genes involved in angiogenesis. During the regeneration 62 genes involved in angiogenesis were identified as up- or down-regulated. Some data were also validated by QPCR. Levels of Vegfa and Kdr (Vegfr-2) mRNAs were very low at day 1 of regeneration and remained unchanged thereafter. The highest expression of Figf gene was found at day 5 while that of Vwf gene at days 1 and 2 after surgery. Levels of Thy1 mRNA increased notably between days 2 and 5 of the experiment. In comparison to control rats, Mc2r (ACTH receptor) expression was lowered at day 1 of the experiment and remained unchanged thereafter. This suggests that enucleation-induced adrenal neoangiogenesis does not require elevated expression of ACTH receptor. Results of our studies strongly suggest that enucleation-induced adrenal regeneration is an angiogenesis-dependent process. Moreover, immunohistochemistry suggests that regenerating adrenal parenchymal cells release numerous angiogenic factors which paracrinally may regulate formation of new vessels.

Evidence suggesting that ghrelin O-acyl transferase inhibitor acts at the hypothalamus to inhibit hypothalamo-pituitary-adrenocortical axis function in the rat

Production of n-octanoyl-modified ghrelin (GHREL), an active form of the peptide requires prohormone processing protease and GHREL O-acyltransferase (GOAT), as well as n-octanoic acid. Recently a selective GOAT antagonist (GO-CoA-Tat) was invented and this tool was used to study the possible role of endogenous GHREL in regulating HPA axis function in the rat. Administration of GOAT inhibitor (GOATi) resulted in a notable decrease in plasma ACTH, aldosterone and corticosterone concentrations at min 60 of experiment. Octanoic acid (OA) administration had no effect on levels of studied hormones. Plasma levels of unacylated and acylated GHREL remained unchanged for 60min after either GOATi or OA administration. Under experimental conditions applied, no significant changes were observed in the levels of GOAT mRNA in hypothalamus, pituitary, adrenal and stomach fundus. After GOATi injection hypothalamic CRH mRNA levels were elevated at 30 min and pituitary POMC mRNA levels at 60 min. Both GOATi and OA lowered basal, but not K(+)-stimulated CRH release by hypothalamic explants and had no effect on basal or CRH-stimulated ACTH release by pituitary slices. Neither GOATi nor OA affected corticosterone secretion by freshly isolated or cultured rat adrenocortical cells. Thus, results of our study suggest that in the rat endogenous GHREL exerts tonic stimulating effect on hypothalamic CRH release. This effect could be demonstrated by administering rats with selected inhibitor of ghrelin O-acyltransferase, the enzyme responsible for GHREL acylation, a process which is absolutely required for both GHSR-1a binding and its central endocrine activities.

Elevated expression of orexin receptor 2 (HCRTR2) in benign prostatic hyperplasia is accompanied by lowered serum orexin A concentrations

In search for the new polypeptides responsible for energy homeostasis which are also involved in regulating the growth and function of the human prostate, we assessed the expression of orexins (OXs) and of orexin receptors (OXRs) in human normal prostate and in benign prostatic hyperplasia (BPH). Conventional RT-PCR revealed the expression of OXR2 in all studied samples obtained either from normal prostates or BPH ones while neither preproorexin (ppOX)nor OXR1 mRNA were detected. In adenomatous prostates, expression levels of OXR2 were 30- to 40-fold higher compared to controls. Western blot analysis demonstrated the presence of OXR2 protein in the studied samples and its expression levels were 4-fold higher in tissue samples from BPH. In normal glands, presence of OXR2-like immunoreactivity was found in the apical parts of epithelial cells as well as in smooth muscle cells of the stroma. Immunostaining for OXR2 was more intense in sections obtained from BPH. Immunohistochemistry did not detect the expression of OXR1-like protein. OXA serum concentrations were lowered in BPH patients (mean ± SE 56±4 ng/ml, n=12; P<0.01) and unaltered in prostate cancer (79±7 ng/ml, n=18) compared to the controls (69±2 ng/ml, n=16). On the contrary, serum OXB levels were similar in all studied groups of patients. We thus have demonstrated the mRNA and protein expression of OXR2, but not of ppOX and OXR1 in both normal and BPH human prostate glands. We also demonstrated notable up-regulation of OXR2 in benign prostatic hyperplasia, an alteration accompanied by lowered serum OXA concentrations. These findings suggest that both OXA and OXR2 may be involved in the pathogenesis and/or maintenance of BPH.

Adiponectin and adiponectin receptor system in the rat adrenal gland: ontogenetic and physiologic regulation, and its involvement in regulating adrenocortical growth and steroidogenesis

Adiponectin (ADN) is a regulatory peptide secreted mostly by adipose tissue and acting via two receptors: AdipoR1 and AdipoR2. Our aim was to investigate expression of adiponectin system genes in the rat adrenal gland as well as its ontogenetic and physiological control. Furthermore, we examined the effects of acute and prolonged activation of HPA axis on ADN system in adipose tissue. By means of QPCR, ADN and AdipoR1 expression was demonstrated in rat adrenal cortex both at mRNA and protein levels, while AdipoR2 could only be detected at mRNA levels. ADN expression level was significantly upregulated in a developing and regenerating adrenal cortex. Globular domain of adiponectin at 10(-9) M stimulated corticosterone output and BrdU incorporation by cultured rat adrenocortical cells. Moreover, both acute (ACTH and ether stress) and prolonged (ACTH) adrenal stimulation resulted in lowered ADN levels, while expression of AdipoR1 and AdipoR2 was upregulated by the acute treatment. Depending on its site of origin, visceral (VAT) or subcutaneous (SAT) adipose tissue responded differently to alterations in HPA axis. VAT expression of ADN and its receptors remained almost unchanged by experimental manipulations. In SAT, on the other hand, expression of ADN and AdipoR2 was markedly increased by ACTH treatment and stress, while dexamethasone suppressed ADN and AdipoR1 mRNA levels. The results of this study provide new evidence for direct and indirect interactions between adipokines and HPA axis.

Expression of the spexin gene in the rat adrenal gland and evidences suggesting that spexin inhibits adrenocortical cell proliferation

Spexin (SPX, also called NPQ) is a recently identified, highly conserved peptide which is processed and secreted. We analysed the SPX gene and its protein product in the rat adrenal gland to ascertain whether SPX is involved in the regulation of corticosteroid secretion of and growth of adrenocortical cells. In adult rat adrenal glands the highest levels of SPX mRNA were present in the glomerulosa (ZG) and fasciculate/reticularis (ZF/R) zones. High SPX gene expression levels were found in freshly isolated adult rat ZG and ZF/R cells. In cultured adrenocortical cells the levels of SPX mRNA were lower than in freshly isolated cells. SPX mRNA expression levels were found to be 2-3 times higher during days 90-540 of postnatal development than found during days 2-45. Prolonged ACTH administration lowered and dexamethasone increased adrenal SPX mRNA levels in vivo. Adrenal enucleation produced a significant linear increase in SPX mRNA levels, with the highest value occurring at day 8 after surgery, with control values taken on day 30 after enucleation. Immunohistochemistry revealed SPX-like immunoreactivity in the entire cortex of the adult male rat and in enucleation-induced regenerating cortex. A concentration of 10-6M SPX peptide stimulated basal aldosterone secretion by freshly isolated ZG. In prolonged exposure of adrenocortical cell primary cultures to SPX (10-6M) resulted in a small increase in corticosterone secretion and a notable decrease in BrdU incorporation. The results suggest the direct involvement of SPX in the regulation of adrenocortical cell proliferation; however, the mechanism of action remains unknown.

Cerebellin and des-cerebellin exert ACTH-like effects on corticosterone secretion and the intracellular signaling pathway gene expression in cultured rat adrenocortical cells--DNA microarray and QPCR studies

Precerebellins (Cbln) belong to the C1q/TNF superfamily of secreted proteins which have diverse functions. They are abundantly expressed in the cerebellum, however, three of them are also expressed in the rat adrenal gland. All members of the Cbln family form homomeric and heteromeric complexes with each other in vitro and it was suggested that such complexes play a crucial role in normal development of the cerebellum. The aim of our study was to investigate whether Cbln1-derived peptides, cerebellin (CER) and des-Ser1-cerebellin (desCER) are involved in regulating biological functions of rat adrenocortical cells. In the primary culture of rat adrenocortical cells, 24 h exposure to CER or desCER notably stimulated corticosterone output and inhibited proliferative activity and similar effects were evoked by ACTH. To study gene transcript regulation by CER, desCER and ACTH, we applied Oligo GEArray DNA Microarray: Rat Signal Transduction Pathway Finder. In relation to the control culture, 13 of the 113 transcripts present on the array were differentially expressed. These transcripts were either up- or down-regulated by ACTH and/or CER or desCER treatment. Validation of DNA Microarray data by QPCR revealed that only 5 of 13 genes studied were differentially expressed. Of those genes, Fos and Icam1 were up-regulated and Egr1 was down-regulated by ACTH, CER and desCER. The remaining two genes, Fasn (insulin signaling pathway) and Hspb1 (HSP27) (stress signaling pathway), were regulated only by CER and desCER, but not by ACTH. Thus, both CER and desCER have effects similar to and different from corticotrophin on the intracellular signaling pathway gene expression in cultured rat adrenocortical cells.

Precerebellin-related genes and precerebellin 1 peptide in the adrenal gland of the rat: expression pattern, localization, developmental regulation and effects on corticosteroidogenesis

Precerebellin (Cbln)-related peptides are known to modulate the secretory activity and growth of the adrenal gland. However, precise expression of the Cbln-related genes and Cbln1 peptide in the adrenal remains unclear. Therefore, we investigated, using RT-PCR, QPCR, Western blotting, immunohistochemistry and hormonal assays, their expression in the adrenals of adult rats and in the course of postnatal ontogenesis. Of the 4 known Cblns, Cbln(1-3) mRNAs were found in the adrenal gland of the adult male rats. Expression patterns of Cbln1 and 3 were similar to each other and different from that of Cbln2. Highest expression of the Cbln1 and 3 genes was observed in the zona glomerulosa (ZG), lower expression was noted in the fasciculata/reticularis and lowest expression was observed in the adrenal medulla. Expression of these genes was also present in freshly isolated rat adrenocortical cells. On the contrary, by means of classic RT-PCR, we demonstrated the presence of mRNAs of CBLN(1-4) in the human adrenal gland. In the rat, highest expression of the Cbln1 and 3 genes was found at postnatal day 2 and was somewhat lower at day 90. On the contrary, expression of the Cbln2 gene was low in adrenals of 2-day-old rats and notably higher at the remaining time points studied (up to day 360). Cerebellin (CER)-like immunoreactivity was observed in the membranes of the adrenal ZG cells, while in the medulla, immunoreactive substances were localized primarily in the cytoplasm of chromaffin cells. Cbln1-like immunoreactivity was present mainly in the cortex of the gland, and reaction products were noted both in the membranes and cytoplasm of adrenocortical cells. Semiquantitative evaluation of Cbln1 protein expression in compartments of the adrenal gland of the adult rat revealed a higher concentration of Cbln1 protein in the cortex than in the medulla of studied rats. We also found that both CER and desCER stimulated basal aldosterone secretion by freshly isolated ZG cells. Thus, the present study provided precise data on expression of the Cbln-related genes and Cbln1 peptide in the adrenal gland of the rat and on their developmental regulation. We also found that, contrary to the human adrenal, in the rat adrenal gland, the Cbln4 gene was not expressed at the mRNA level.

Neuromedin U directly stimulates growth of cultured rat calvarial osteoblast-like cells acting via the NMU receptor 2 isoform

The neuromedin U (NMU) system is composed of NMU, neuromedin S (NMS) and their receptors NMUR1 and NMUR2. This system is involved in the regulation of energy homeostasis, neuroendocrine functions, immune response, circadian rhythm and spermatogenesis. The present study aimed to investigate the possible role of the NMU system in regulating functions of cultured rat calvarial osteoblast-like (ROB) cells. By using QPCR, high expression of NMU mRNA was found in freshly isolated ROB cells while after 7, 14, and 21 days of culture, expression of the studied gene was very low. In contrast, NMUR2 mRNA expression in freshly isolated ROB cells was negligible and very high in cultured cells. The highest NMUR2 mRNA expression was observed at day 7, and was followed by lower levels at days 14 and 21 of culture. Neither NMS nor NMUR1 mRNA was found in studied cells. Exposure of cultured ROB cells to NMU8 at concentrations 10(-6) to 10(-10) M had no effect on expression levels of the genes. During the entire culture period, NMU8 did not affect osteocalcin production, but stimulated proliferative activity of ROB cells at days 14 and 21 of culture. Thus, we demonstrated that cultured rat calvarial osteoblast-like cells are provided with NMUR2, the receptor isoform typical for the central nervous system. Acting via this receptor NMU8 stimulates proliferation of cultured cells and has no effect on their differentiated function (osteocalcin secretion).