The role of MAPK11/12/13/14 (p38 MAPK) protein in dopamine agonist-resistant prolactinomas

BACKGROUND

Prolactinoma is a functional pituitary adenoma that secretes excessive prolactin. Dopamine agonists (DAs) such as bromocriptine (BRC) are the first-line treatment for prolactinomas, but the resistance rate is increasing year by year, creating a clinical challenge. Therefore, it is urgent to explore the molecular mechanism of bromocriptine resistance in prolactinomas. Activation of the P38 MAPK pathway affects multidrug resistance in tumours. Our previous studies have demonstrated that inhibiting MAPK14 can suppress the occurrence of prolactinoma, but the role of MAPK11/12/13/14 (p38 MAPK) signalling in dopamine agonist-resistant prolactinomas is still unclear.

METHODS

A prolactinoma rat model was established to determine the effect of bromocriptine on MAPK11/12/13/14 signalling. DA-resistant GH3 cells and DA-sensitive MMQ cells were used, and the role of MAPK11/12/13/14 in bromocriptine-resistant prolactinomas was preliminarily verified by western blot, RT-qPCR, ELISA, flow cytometry and CCK-8 experiments. The effects of MAPK11 or MAPK14 on bromocriptine-resistant prolactinomas were further verified by siRNA transfection experiments.

RESULTS

Bromocriptine was used to treat rat prolactinoma by upregulating DRD2 expression and downregulating the expression level of MAPK11/12/13/14 in vivo experiments. The in vitro experiments showed that GH3 cells are resistant to bromocriptine and that MMQ cells are sensitive to bromocriptine. Bromocriptine could significantly reduce the expression of MAPK12 and MAPK13 in GH3 cells and MMQ cells. Bromocriptine could significantly reduce the expression of MAPK11, MAPK14, NF-κB p65 and Bcl2 in MMQ but had no effect on MAPK11, MAPK14, NF-κB p65 and Bcl2 in GH3 cells. In addition, knockdown of MAPK11 and MAPK14 in GH3 cells by siRNA transfection reversed the resistance of GH3 cells to bromocriptine, and haloperidol (HAL) blocked the inhibitory effect of bromocriptine on MAPK14, MAPK11, and PRL in MMQ cells. Our findings show that MAPK11 and MAPK14 proteins are involved in bromocriptine resistance in prolactinomas.

CONCLUSION

Bromocriptine reduces the expression of MAPK11/12/13/14 in prolactinomas, and MAPK11 and MAPK14 are involved in bromocriptine resistance in prolactinomas by regulating apoptosis. Reducing the expression of MAPK11 or MAPK14 can reverse bromocriptine resistance in prolactinomas.

Influence of the expression vector and its elements on recombinant human prolactin synthesis in Escherichia coli; co-directional orientation of replication and transcription is highly critical

The aim of the present work was to define a bacterial expression system that is particularly efficient for the synthesis of recombinant human prolactin (hPRL). In previous work, based on experiments that were basically carried out in parallel with the present ones, the synthesis of rec-hPRL by the p1813-hPRL vector in E. coli HB2151 was >500 mg/L, while it was much lower here (2.5-4-fold), in the RB791 and RRI strains. The highest positive influence on rec-hPRL synthesis was due to the transcription-replication co-orientation of hPRL cDNA and the ori/antibiotic resistance gene, responsible for up to a ~ 5-6-fold higher expression yield. In conclusion, this work confirmed that each bacterial strain of E. coli has a genetic background that can allow a different level of heterologous protein synthesis. The individual study of each element indicated that its action critically depends on the reading orientation in which it is located inside the vector: co-directional orientation of replication and transcription, in fact, greatly increased the level of rec-hPRL expression.

Tumor stem-like cells isolated from MMQ cells resist to dopamine agonist treatment

Although tumor stem-like cells (TSLCs) have been studied in a range of malignant tumors, evidence for the presence of these cells in pituitary adenomas needs further exploration. Here, we identified a small subset of sphere-forming cells possess tumor stem-like cell properties in rat prolactinoma MMQ cells, which resist to dopamine agonist treatment. Comparing to MMQ cells, sphere-forming cells showed higher cell viability after dopamine agonist (DA) treatment. Furthermore, the cells showed lower expression of prolactin (PRL) and dopamine 2 receptor (D2R). On the contrary, the daughter tumor cells differentiated from these cells restored the sensitivity to DA and showed high expression of PRL and D2R. The lower D2R expression and DA resistance might be due to DNA hypermethylation of D2R promoter. Our study demonstrates that the sphere-forming cells isolated from MMQ cells possess the trait of TSLCs and resist to DA treatment, which offers the opportunity to further investigate the mechanisms underlying tumor recurrence based on TSLCs.

Prolactin affects the disappearance of ALV-J viremia in vivo and inhibits viral infection

Based on the RNA-seq data of chicken spleen tissues infected with J subgroup avian leukosis virus (ALV-J), we found that prolactin (PRL) gene was one of differentially expressed gene. We measured ALV-J viremia and PRL levels in the plasma of two groups of ALV-J-infected adult chickens. Furthermore, recombinant chicken PRL (cPRL) was used to assess how cPRL affects ALV-J virus replication both in vivo and in vitro. The results showed that PRL levels in the plasma of adult chickens infected with ALV-J were lower than those of uninfected chickens, and that the difference was more significant in the avian leukemia pathological apparent changes. Notably, the fluctuations in PRL levels might influence the disappearance of ALV-J viremia in chickens. The in vitro results showed that preincubating DF-1 cells with cPRL before ALV-J infection elicited the best antiviral effects. Moreover, these effects were not dose-dependent. in vivo, injection of cPRL into ALV-J-infected chicks could reduce the levels of viremia at the 14 days post infection (dpi). Additionally, the expression of the interferon-stimulated genes oligoadenylate synthetase-like (OSAL) and vasoactive intestinal peptide (VIP) increased, and that of the proinflammatory cytokine-encoding TNTα, IL-1β, and IL-6 genes decreased in the spleens of ALV-J-infected chicks injected with cPRL, leading to inhibition of viral replication at the 7 dpi. Collectively, our data demonstrated that PRL plays an important antiviral role in the immune response to ALV-J infection. This is the first report of the relationship between ALV-J infection and PRL. It is of great significance for the prevention and control of ALV-J.

Galanin and prolactin expression in relation to parental care in two sympatric cichlid species from Lake Tanganyika

Our understanding of the hormonal mechanisms underlying parental care mainly stems from research on species with uniparental care. Far less is known about the physiological changes underlying motherhood and fatherhood in biparental caring species. Here, using two biparental caring cichlid species (Neolamprologus caudopunctatus and Neolamprologus pulcher), we explored the relative gene-expression levels of two genes implicated in the control of parental care, galanin (gal) and prolactin (prl). We investigated whole brain gene expression levels in both, male and female caring parents, as well as in non-caring individuals of both species. Caring males had higher prl and gal mRNA levels compared to caring females in both fish species. Expression of gal was highest when young were mobile and the need for parental defense was greatest and gal was lowest during the more stationary egg tending phase in N. caudopunctatus. The onset of parenthood was associated with lower expression of prl and higher expression of gal in N. pulcher, but this pattern was not observed in N. caudopunctatus. Our study demonstrates that gal gene expression is correlated with changes in parental care in two biparental cichlid species and extends both knowledge and taxonomic coverage of the possible neurogenetic mechanisms underlying parental care.

PRL Mutation Causing Alactogenesis: Insights Into Prolactin Structure and Function Relationships

CONTEXT

Isolated prolactin deficiency is a rare disorder manifesting as absence of puerperal lactation. We identified a 2-generation family with 3 women experiencing alactogenesis.

OBJECTIVE

We hypothesized a heterozygous genetic mutation.

METHODS

This was a family-based study. Two generations of women (proband, sister, and niece) with puerperal alactogenesis and one control were studied. Prolactin levels in the 3 women ranged from 0.618 to 1.4 ng/mL (range, 2.8-29.2 ng/mL). All the women had regular menstrual cycles during their reproductive years. The niece required fertility treatment to become pregnant and the proband and sister underwent menopause before age 45 years. Prolactin gene (PRL) exons 1 to 5 were sequenced. We sought a heterozygous, deleterious gene variant with functional consequences.

RESULTS

We identified a heterozygous mutation (c.658C > T) changing CGA to TGA (p.Arg220Ter) in exon 5 of the prolactin gene. Transfection of PRL containing the stop gain mutation resulted in similar intracellular prolactin levels compared to PRL wild type, but little detectable immunoactive or bioactive prolactin in conditioned medium. Prolactin secretion was also impaired by a PRL stop gain mutation deleting both of the terminal cysteine amino acids (c.652A > T; p.Lys218Ter).

CONCLUSION

This is the first report of a PRL mutation causing familial prolactin deficiency and alactogenesis. The loss of the terminal cysteine resulted in failure of prolactin secretion. Secretion was not rescued by deleting the penultimate cysteine, with which it forms a disulfide bond. These data suggest that the PRL C terminal is critical for protein secretion.

Nesfatin-1 and Nesfatin-1-like peptide suppress basal and TRH-Induced expression of prolactin and prolactin regulatory element-binding protein mRNAs in rat GH3 somatolactotrophs

Prolactin (PRL), mainly synthesized and secreted by the lactotrophs and somatolactotrophs of the anterior pituitary, is a pleiotropic hormone that regulates lactation. In the last decade, nesfatin-1 (NESF) and NESF-like peptide (NLP), encoded in nucleobindin 1 and 2 (NUCB1 and NUCB2), respectively, were characterized as metabolic factors with a potential role in the control of pituitary hormones. We hypothesized that NUCBs and their encoded peptides (NESF and NLP) suppress PRL transcription in the pituitary. The main objective of this research was to determine whether exogenous NESF and NLP, and/or endogenous NUCB1 and NUCB2 regulate the expression of prl and preb mRNAs. Using immortalized rat somatolactotrophs (GH3 cells), dose-response studies were performed to test whether NESF and NLP affect prl and preb. Moreover, the ability of these peptides to modulate the effects of the PRL stimulator thyrotropin releasing hormone (TRH) was studied. Besides, the effects of siRNA-mediated knockdown of endogenous NUCBs on prl and preb mRNAs were determined. NESF and NLP reduced the transcription of prl and preb in GH3 cells. Both NESF and NLP also prevented the stimulatory effects of TRH prl and preb expression. The knockdown of endogenous NUCB1 attenuates both basal prl and TRH-induced expression of prl and preb, while the silencing of NUCBs did not affect the actions of exogenous NESF or NLP. Overall, this work reveals that NUCBs and encoded-peptides are novel regulators of PRL. Future research should test whether the effects observed here in GH3 cells are preserved both in vivo and at the post-transcriptional level.

A mutation of the β-domain in POU1F1 causes pituitary deficiency due to dominant PIT-1β expression

BACKGROUND

POU1F1 encodes both PIT-1α, which plays pivotal roles in pituitary development and GH, PRL and TSHB expression, and the alternatively spliced isoform PIT-1β, which contains an insertion of 26-amino acids (β-domain) in the transactivation domain of PIT-1α due to the use of an alternative splice acceptor at the end of the first intron. PIT-1β is expressed at much lower levels than PIT-1α and represses endogenous PIT-1α transcriptional activity. Although POU1F1 mutations lead to combined pituitary hormone deficiency (CPHD), no patients with β-domain mutations have been reported.

RESULTS

Here, we report that a three-generation family exhibited different degrees of CPHD, including growth hormone deficiency with intrafamilial variability of prolactin/TSH insufficiency and unexpected prolactinoma occurrence. The CPHD was due to a novel POU1F1 heterozygous variant (c.143-69T>G) in intron 1 of PIT-1α (RefSeq number NM_000306) or as c.152T>G (p.Ile51Ser) in exon 2 of PIT-1β (NM_001122757). Gene splicing experiments showed that this mutation yielded the PIT-1β transcript without other transcripts. The lymphocyte PIT-1β mRNA expression was significantly higher in the patients with the heterozygous mutation than a control. A luciferase reporter assay revealed that the PIT-1β-Ile51Ser mutant repressed PIT-1α and abolished transactivation capacity for the rat prolactin promoter in GH3 pituitary cells.

CONCLUSIONS

We describe, for the first time, that the PIT-1β mutation can cause CPHD through a novel genetic mechanism, such as PIT-1β overexpression, and that POU1F1 mutation might be associated with a prolactinoma. Analysis of new patients and long-term follow-up are needed to clarify the characteristics of PIT-1β mutations.

Tumor-secreted proliferin-1 regulates adipogenesis and lipolysis in cachexia

Cancer-associated cachexia (CAC) is a common syndrome in cancer patients and is characterized by loss of body weight accompanied by the atrophy of fat and skeletal muscle. Metabolic changes are a critical factor in CAC; however, the mechanisms through which tumors inhibit adipogenesis and promote lipolysis are poorly understood. To clarify these mechanisms, we investigated adipogenesis-limiting factors released by tumors in a cell culture system. We identified proliferin-1 (PLF-1), a member of the growth hormone/prolactin gene family, as a key factor secreted from certain tumors that inhibited preadipocyte maturation and promoted the lipolysis of mature adipocytes. Importantly, mice transplanted with PLF-1-depleted tumor cells were protected from fat loss due to CAC. These data show that tumor-secreted PLF-1 plays an essential role in impaired adipogenesis and accelerated lipolysis and is a potential therapeutic target against CAC.

Transcription Factor Pit-1 Affects Transcriptional Timing in the Dual-Promoter Human Prolactin Gene

Gene transcription occurs in short bursts interspersed with silent periods, and these kinetics can be altered by promoter structure. The effect of alternate promoter architecture on transcription bursting is not known. We studied the human prolactin (hPRL) gene that contains 2 promoters, a pituitary-specific promoter that requires the transcription factor Pit-1 and displays dramatic transcriptional bursting activity and an alternate upstream promoter that is active in nonpituitary tissues. We studied large hPRL genomic fragments with luciferase reporters, and used bacterial artificial chromosome recombineering to manipulate critical promoter regions. Stochastic switch mathematical modelling of single-cell time-lapse luminescence image data revealed that the Pit-1-dependent promoter showed longer, higher-amplitude transcriptional bursts. Knockdown studies confirmed that the presence of Pit-1 stabilized and prolonged periods of active transcription. Pit-1 therefore plays an active role in establishing the timing of transcription cycles, in addition to its cell-specific functions.

The Choroid Plexus Is an Alternative Source of Prolactin to the Rat Brain

Among the more than 300 functions attributed to prolactin (PRL), this hormone has been associated with the induction of neurogenesis and differentiation of olfactory neurons especially during pregnancy, which are essential for maternal behavior. Despite the original hypothesis that PRL enters the central nervous system through a process mediated by PRL receptors (PRLR) at the choroid plexus (CP), recent data suggested that PRL transport into the brain is independent of its receptors. Based on transcriptomic data suggesting that PRL could be expressed in the CP, this work aimed to confirm PRL synthesis and secretion by CP epithelial cells (CPEC). The secretion of PRL and the distribution of PRLR in CPEC were further characterized using an in vitro model of the rat blood-cerebrospinal fluid barrier. RT-PCR analysis of PRL transcripts showed its presence in pregnant rat CP, in CPEC, and in the rat immortalized CP cell line, Z310. These observations were reinforced by immunocytochemistry staining of PRL in CPEC and Z310 cell cytoplasm. A 63-kDa immunoreactive PRL protein was detected by Western blot in CP protein extracts as well as in culture medium incubated with rat pituitary and samples of rat cerebrospinal fluid and serum. Positive immunocytochemistry staining of PRLR was present throughout the CPEC cytoplasm and in the apical and basal membrane of these cells. Altogether, our evidences suggest that CP is an alternative source of PRL to the brain, which might impact neurogenesis of olfactory neurons at the subventricular zone, given its proximity to the CP.

Effect of Hordei Fructus Germinatus on differential gene expression in the prolactin signaling pathway in the mammary gland of lactating rats

ETHNOPHARMACOLOGICAL RELEVANCE

In China, Hordei Fructus Germinatus (HFG) is the germinated and dried fruit of Hordeum vulgare L, which is commonly used in clinical Chinese medicine. Traditional Chinese Medicine (TCM) theory holds that HFG can be both medicinal and edible, which means that it is derived from food medicine. Raw HFG and roasted HFG are used to treat hypogalactia, hyperprolactinemia and indigestion. In recent years, the lactogenic and galactophygous effects of HFG have attracted increasing attention. Nevertheless, there is much confusion over the use of raw and processed HFG, and the mechanism of its lactogenic effect seems remains poorly understood.

AIM OF THE STUDY

This study aimed to explore the lactogenic effect of raw HFG and roasted HFG on rats with overloaded lactation and to reveal the underlying molecular mechanism.

MATERIALS AND METHODS

Raw and processed HFG water decoctions were given to overloaded lactation model rats at a dose of 1.7800 g kg^-1·d^-1, and the control group was given the same volume of water. The lactogenic effect of raw and processed HFG was evaluated by measuring daily lactation, body weight and pup body weight, serum PRL, E2, and GH contents after parturition, and the pathological characteristics of mammary tissue sections. cDNA microarrays can be used to screen diverse gene expression patterns and signaling pathways related to prolactin. The expression of relevant differentially expressed genes was verified by real-time PCR and western blotting.

RESULTS

In vivo experiments demonstrated that the raw HFG water decoction stimulated mammogenesis, accelerated the transformation of the lobular acinar system, resulted in denser mammary epithelial cells and thicker glandular ducts that were full of milk and facilitated the secretion of milk. Moreover, HFG increased PRL, E2, and GH levels, pup body weight, daily lactation and the body weight of lactating rats. Following gene chip identification, KEGG pathway enrichment analysis revealed genes that were highly related to prolactin in the prolactin signaling pathway and JAK-STAT signaling pathway, and the main differentially expressed genes were Jak2 (down), Stat5α (up), cyclin D1 (up), SOCS1 (up), CISH (down) and PRLR (up). Compared with the control group, RT-PCR results indicated that Jak2 and CISH were downregulated and that Stat5α, cyclin D1, SOCS1 and PRLR were upregulated. Western blot assays showed that PRLR, STAT5α and cyclin D1 levels in the mammary glands of the raw HFG water decoction group were significantly increased, which was consistent with the results of cDNA microarray screening.

CONCLUSION

The present study reveals that raw HFG effectively enhances lactation in rats, possibly by influencing the prolactin/JAK-STAT signaling pathway.

Mice with an RGS-insensitive Gαi2 protein show growth hormone axis dysfunction

Mice carrying an RGS-insensitive Gαi2 mutation display growth retardation early after birth. Although the growth hormone (GH)-axis is a key endocrine modulator of postnatal growth, its functional state in these mice has not been characterized. The present study was undertaken to address this issue. Results revealed that pituitary mRNA levels for GH, prolactin (PRL), somatostatin (SST), GH-releasing-hormone receptor (GHRH-R) and GH secretagogue receptor (GHS-R) were decreased in mutants compared to controls. These changes were reflected by a significant decrease in plasma levels of GH, IGF-1 and IGF-binding protein-3 (IGFBP-3). Mutants were also less responsive to GHRH and ghrelin (GhL) on GH stimulation of release from pituitary primary cell cultures. In contrast, they were more sensitive to the inhibitory effect of SST. These data provide the first evidence for an alteration of the functional state of the GH-axis in Gαi2G184S mice that likely contributes to their growth retardation.

Screening and identification of potential biomarkers for obstructive sleep apnea via microarray analysis

Obstructive sleep apnea (OSA) is a common chronic disease and increases the risk of cardiovascular disease, metabolic and neuropsychiatric disorders, resulting in a considerable socioeconomic burden. This study aimed to identify potential key genes influence the mechanisms and consequences of OSA.Gene expression profiles related to OSA were obtained from Gene Expression Omnibus (GEO) database. Differentially expressed genes (DEGs) in subcutaneous adipose tissues from OSA compared with normal tissues were screened using R software, followed by gene ontology (GO) and pathway enrichment analyses. Subsequently, a protein-protein interaction (PPI) network for these DEGs was constructed by STRING, and key hub genes were extracted from the network with plugins in Cytoscape. The hub genes were further validated in another GEO dataset and assessed by receiver operating characteristic (ROC) analysis and Pearson correlation analysis.There were 373 DEGs in OSA samples in relative to normal controls, which were mainly associated with olfactory receptor activity and olfactory transduction. Upon analyses of the PPI network, GDNF, SLC2A2, PRL, and SST were identified as key hub genes. Decreased expression of the hub genes was association with OSA occurrence, and exhibited good performance in distinguishing OSA from normal samples based on ROC analysis. Besides, the Pearson method revealed a strong correlation between hub genes, which indicates that they may act in synergy, contributing to OSA and related disorders.This bioinformatics research identified 4 hub genes, including GDNF, SLC2A2, PRL, and SST which may be new potential biomarkers for OSA and related disorders.

Prolactin synergizes with canonical Wnt signals to drive development of ER+ mammary tumors via activation of the Notch pathway

Prolactin (PRL) cooperates with other factors to orchestrate mammary development and lactation, and is epidemiologically linked to higher risk for breast cancer. However, how PRL collaborates with oncogenes to foster tumorigenesis and influence breast cancer phenotype is not well understood. To understand its interactions with canonical Wnt signals, which elevate mammary stem cell activity, we crossed heterozygous NRL-PRL mice with Apc^Min/+ mice and treated pubertal females with a single dose of mutagen. PRL in the context of Apc^Min/+ fueled a dramatic increase in tumor incidence in nulliparous mice, compared to Apc^Min/+ alone. Although carcinomas in both NRL-PRL/Apc^Min/+ and Apc^Min/+ females acquired a mutation in the remaining wildtype Apc allele and expressed abundant β-catenin, PRL-promoted tumors displayed higher levels of Notch-driven target genes and Notch-dependent cancer stem cell activity, compared to β-catenin-driven activity in Apc^Min/+ tumors. This PRL-induced shift to dominant Notch signals was evident in preneoplastic epithelial hyperplasias at 120 days of age. In NRL-PRL/Apc^Min/+ females, rapidly proliferating hyperplasias, characterized by β-catenin at cell junctions and high NOTCH1 expression, contrasted with slower growing lesions with nuclear β-catenin in Apc^Min/+ females. These studies demonstrate that PRL can powerfully modulate the incidence and phenotype of mammary tumors, shedding light on mechanisms whereby PRL elevates risk of breast cancer.

Calcium dynamics and chromatin remodelling underlie heterogeneity in prolactin transcription

Pituitary cells have been reported to show spontaneous calcium oscillations and dynamic transcription cycles. To study both processes in the same living cell in real time, we used rat pituitary GH3 cells stably expressing human prolactin-luciferase or prolactin-EGFP reporter gene constructs loaded with a fluorescent calcium indicator and measured activity using single-cell time-lapse microscopy. We observed heterogeneity between clonal cells in the calcium activity and prolactin transcription in unstimulated conditions. There was a significant correlation between cells displaying spontaneous calcium spikes and cells showing spontaneous bursts in prolactin expression. Notably, cells showing no basal calcium activity showed low prolactin expression but elicited a significantly greater transcriptional response to BayK8644 compared to cells showing basal calcium activity. This suggested the presence of two subsets of cells within the population at any one time. Fluorescence-activated cell sorting was used to sort cells into two populations based on the expression level of prolactin-EGFP however, the bimodal pattern of expression was restored within 26 h. Chromatin immunoprecipitation showed that these sorted populations were distinct due to the extent of histone acetylation. We suggest that maintenance of a heterogeneous bimodal population is a fundamental characteristic of this cell type and that calcium activation and histone acetylation, at least in part, drive prolactin transcriptional competence.

Retrospective analysis of 19 patients with 6-Pyruvoyl Tetrahydropterin Synthase Deficiency: Prolactin levels inversely correlate with growth

BACKGROUND

Pyruvoyl Tetrahydropterin Synthase (PTPS) Deficiency is the most common form of BH4 deficiency resulting in hyperphenylalaninemia. It can have variable clinical severity and there is limited information on the clinical presentation, natural history and effectiveness of newborn screening for this condition.

METHODS

Retrospective data (growth and clinical parameters, biochemical and genetic testing results, treatment) were collected from 19 patients with PTPS deficiency in different centers, to evaluate biochemical and clinical outcomes. Descriptive statistics was used for qualitative variables, while linear regression analysis was used to correlate quantitative variables.

RESULTS

Patients with PTPS deficiency had an increased incidence of prematurity (4/18) with an average gestational age only mildly reduced (37.8 ± 2.4 weeks) and low birth weight (-1.14 ± 0.97 SD below that predicted for gestational age). With time, weight and height approached normal.

VALUES

All patients were identified by newborn screening for an elevated phenylalanine level. However, phenylalanine levels were normal in two whose testing was performed at or before 24 h of age. Sapropterin dihydrochloride treatment normalized phenylalanine levels. Molecular testing identified novel variants in the PTS gene, some of which present in more than one affected family. The neurotransmitter derivatives 5-hydroxyindoleacetic acid (5HIAA) and homovanillic acid (HVA) in the CSF were decreased in most cases except in 2 families with the peripheral form of PTPS deficiency. With time, HVA and 5HIAA became abnormally low in two of these patients requiring therapy. Prolactin (whose secretion is inhibited by dopamine) levels were elevated in several patients with PTPS deficiency and inversely correlated with the z-scores for height (p < 0.01) and weight (p < 0.05). Most patients with PTPS deficiency had delayed development early in life, improving around school age with IQs mostly in the normal range, with a small decline in older individuals. From a neurological standpoint, most patients had normal brain MRI and minor EEG anomalies, although some had persistent neurological symptoms.

DISCUSSION

Patients with PTPS deficiency have not only an increased incidence of prematurity, but also decreased birth weight when corrected for gestational age. Hyperphenylalaninemia can be absent in the first day of life. Therapy with sapropterin dihydrochloride normalizes phenylalanine levels and neurotransmitter precursors can improve CSF neurotransmitter metabolites levels. Insufficient dopaminergic stimulation (as seen from elevated prolactin) might result in decreased height in patients with PTPS deficiency. Despite early delays in development, many patients can achieve independence in adult life, with usually normal neuroimaging and EEG.

Transcriptional regulation of prolactin in a euryhaline teleost: Characterisation of gene promoters through in silico and transcriptome analyses

The sensitivity of prolactin (Prl) cells of the Mozambique tilapia (Oreochromis mossambicus) pituitary to variations in extracellular osmolality enables investigations into how osmoreception underlies patterns of hormone secretion. Through the actions of their main secretory products, Prl cells play a key role in supporting hydromineral balance of fishes by controlling the major osmoregulatory organs (ie, gill, intestine and kidney). The release of Prl from isolated cells of the rostral pars distalis (RPD) occurs in direct response to physiologically relevant reductions in extracellular osmolality. Although the particular signal transduction pathways that link osmotic conditions to Prl secretion have been identified, the processes that underlie hyposmotic induction of prl gene expression remain unknown. In this short review, we describe two distinct tilapia gene loci that encode Prl177 and Prl188 . From our in silico analyses of prl177 and prl188 promoter regions (approximately 1000 bp) and a transcriptome analysis of RPDs from fresh water (FW)- and seawater (SW)-acclimated tilapia, we propose a working model for how multiple transcription factors link osmoreceptive processes with adaptive patterns of prl177 and prl188 gene expression. We confirmed via RNA-sequencing and a quantitative polymerase chain reaction that multiple transcription factors emerging as predicted regulators of prl gene expression are expressed in the RPD of tilapia. In particular, gene transcripts encoding pou1f1, stat3, creb3l1, pbxip1a and stat1a were highly expressed; creb3l1, pbxip1a and stat1a were elevated in fish acclimated to SW vs FW. Combined, our in silico and transcriptome analyses set a path for resolving how adaptive patterns of Prl secretion are achieved via the integration of osmoreceptive processes with the control of prl gene transcription.

Effects of tank color brightness on the body color, somatic growth, and endocrine systems of rainbow trout Oncorhynchus mykiss

We investigated the effects of tank brightness on body color, growth, and endocrine systems of rainbow trout (Oncorhynchus mykiss). Five different tank colors that produce varying levels of brightness were used, including black, dark gray [DG], light gray [LG], white, and blue. The fish were reared in these tanks for 59 days under natural photoperiod and water temperature. The body color was affected by tank brightness, such that body color brightness was correlated with tank brightness (white-housed ≥ LG-housed ≥ DG-housed ≥ blue-housed ≥ black-housed). No difference in somatic growth was observed among the fish reared in the five tanks. The mRNA levels of melanin-concentrating hormone (mch1) was higher in white-housed fish than those in the other tanks, and the mRNA levels of proopiomelanocortins (pomc-a and pomc-b) were higher in fish housed in a black tank than those in other tanks. mRNA level of somatolactin, a member of growth hormone family, was higher in black-housed fish than those in white-housed fish. The mRNA levels of mch1 and mch2 in blue-housed fish were similar to those in black-housed fish, while the mRNA levels of pomc-a and pomc-b in blue-housed fish were similar to those in white-housed fish. The current results suggest that tank color is not related to fish growth, therefore any color of conventional rearing tank can be used to grow fish. Moreover, the association between somatolactin with body color changes is suggested in addition to the role of classical MCH and melanophore stimulating hormone derived from POMC.

Development of a genetic evaluation for hair shedding in American Angus cattle to improve thermotolerance

BACKGROUND

Heat stress and fescue toxicosis caused by ingesting tall fescue infected with the endophytic fungus Epichloë coenophiala represent two of the most prevalent stressors to beef cattle in the United States and cost the beef industry millions of dollars each year. The rate at which a beef cow sheds her winter coat early in the summer is an indicator of adaptation to heat and an economically relevant trait in temperate or subtropical parts of the world. Furthermore, research suggests that early-summer hair shedding may reflect tolerance to fescue toxicosis, since vasoconstriction induced by fescue toxicosis limits the ability of an animal to shed its winter coat. Both heat stress and fescue toxicosis reduce profitability partly via indirect maternal effects on calf weaning weight. Here, we developed parameters for routine genetic evaluation of hair shedding score in American Angus cattle, and identified genomic loci associated with variation in hair shedding score via genome-wide association analysis (GWAA).

RESULTS

Hair shedding score was moderately heritable (h2 = 0.34 to 0.40), with different repeatability estimates between cattle grazing versus not grazing endophyte-infected tall fescue. Our results suggest modestly negative genetic and phenotypic correlations between a dam's hair shedding score (lower score is earlier shedding) and the weaning weight of her calf, which is one metric of performance. Together, these results indicate that economic gains can be made by using hair shedding score breeding values to select for heat-tolerant cattle. GWAA identified 176 variants significant at FDR < 0.05. Functional enrichment analyses using genes that were located within 50 kb of these variants identified pathways involved in keratin formation, prolactin signalling, host-virus interaction, and other biological processes.

CONCLUSIONS

This work contributes to a continuing trend in the development of genetic evaluations for environmental adaptation. Our results will aid beef cattle producers in selecting more sustainable and climate-adapted cattle, as well as enable the development of similar routine genetic evaluations in other breeds.

Mammary gland-specific regulation of GNRH and GNRH-receptor gene expression is likely part of a local autoregulatory system in female vizcachas (Rodentia: Chinchillidae)

In addition to key mammotrophic hormones such as the pituitary prolactin (PRL) and the ovarian steroids progesterone and estradiol, there are local factors that modulate the tissue dynamics of the mammary glands during pregnancy and lactation. By immunohistochemistry and RT-PCR, we found local transcription and translation of gonadotropin-releasing hormone (GNRH), GNRH receptor (GNRHR), PRL and PRL receptor (PRLR) in mammary glands of adult vizcachas during pregnancy and lactation. Both GNRH and GNRHR showed a lag between protein expression and gene transcription throughout the gestational period: while the highest transcription levels of these genes were recorded at early-pregnancy, the epithelial immunoexpressions of both showed their maximum during lactation. RIA results corroborated the presence of GNRH in mammary glands at all the analyzed stages and confirmed the maximum amount of this peptide in the lactating group. Significant amounts of GNRH were detected in milk samples as well. Conversely, PRL and PRLR shared similar protein and gene expression profiles, all exhibiting maximum values during lactation. GNRH peptide content in mammary glands of females with sulpiride-induced hyperprolactinemia (HP) was significantly lower than that of control females (CT). Although PRL mRNA levels remained unchanged, there was a marked increase in theα-lactalbumin (LALBA) transcription in mammary glands of HP- vs CT-females. These results suggest that after targeting mammary glands, PRL stimulates the expression of milk protein genes, but also, tempers the local expression of GNRH. Mammary gland-explantssupplemented with a GNRH analogue (GN-explants) had no differences in terms of PRLR orLALBA transcription levels compared to CT-explants, so the mammary PRLR signaling would not appear to be modulated by GNRH. Yet, mRNA expression levels of both GNRH and the GNRHR-downstream factor, EGR1, were significantly higher in GN-explants compared to that of CT which would point to a GNRH-positive feedback mechanism. In summary, the local coupled expression of GNRH, GNRHR and EGR1 in the mammary gland throughout pregnancy of vizcachas, the PRL-dependent mammary GNRH secretion as well as the GNRH positive feedback on its own transcription suggest an autocrine-paracrine regulatory mechanism and propose an active role for GNRH in mammary gland tissue remodeling.

Inhibiting MAPK14 showed anti-prolactinoma effect

BACKGROUND

The specific underlying pathogenesis of prolactinoma has not been clarified yet, to the best of our knowledge. p38 mitogen-activated protein kinase (MAPK) signaling including p38α MAPK (MAPK14), p38β (MAPK11), p38γ (MAPK12) and p38δ (MAPK13) is associated with the development and progression of several types of cancer.

METHODS

Immunofluorescence analysis was performed on the prolactin (PRL) and MAPK14 expressions of pituitary gland in C57BL/6 mice and human prolactinoma specimen. In the present study, the role of MAPK14 in prolactinoma was determined using estradiol-induced mice and dopamine D2 receptor knockout (DRD2^-/-) mice models in C57BL/6 wild-type (WT), MAPK14^-/- and DRD2^-/-MAPK14^+/- mice. GH3 cells were transfected with different sets of MAPK14 small interfering RNA, which to study MAPK14 and PRL expression in GH3 cells.

RESULTS

Immunofluorescence analysis showed that PRL and MAPK14 expression were colocalized and increased in the pituitary gland of mice and human prolactinoma specimen compared with the control specimen. It was shown that PRL and MAPK14 expression was colocalized and increased significantly in the pituitary gland of estradiol-injected prolactinoma mice compared with the control mice. Knockout of MAPK14 significantly inhibited tumor overgrowth, and PRL expression was decreased in estradiol-induced mice. Furthermore, MAPK14 knockout of DRD2^-/-MAPK14^+/- mice significantly reduced the overgrowth of pituitary gland and PRL production and secretion compared with DRD2^-/- mice. MAPK14 knockout using siRNA inhibited PRL production in GH3 cells.

CONCLUSION

These results suggest that MAPK14 serves a promoting role in the formation of prolactinoma, and highlights the potential of MAPK14 as a potential therapeutic target in the treatment of prolactinoma.

Somatic SF3B1 hotspot mutation in prolactinomas

The genetic basis and corresponding clinical relevance of prolactinomas remain poorly understood. Here, we perform whole genome sequencing (WGS) on 21 patients with prolactinomas to detect somatic mutations and then validate the mutations with digital polymerase chain reaction (PCR) analysis of tissue samples from 227 prolactinomas. We identify the same hotspot somatic mutation in splicing factor 3 subunit B1 (SF3B1R625H) in 19.8% of prolactinomas. These patients with mutant prolactinomas display higher prolactin (PRL) levels (p = 0.02) and shorter progression-free survival (PFS) (p = 0.02) compared to patients without the mutation. Moreover, we identify that the SF3B1R625H mutation causes aberrant splicing of estrogen related receptor gamma (ESRRG), which results in stronger binding of pituitary-specific positive transcription factor 1 (Pit-1), leading to excessive PRL secretion. Thus our study validates an important mutation and elucidates a potential mechanism underlying the pathogenesis of prolactinomas that may lead to the development of targeted therapeutics.

The Transcription Factor NR4A2 Plays an Essential Role in Driving Prolactin Expression in Female Pituitary Lactotropes

Differentiation of the hormone-producing cells of the pituitary represents an informative model of cell fate determination. The generation and maintenance of 2 pituitary lineages, the growth hormone (GH)- producing somatotropes and the prolactin (PRL)- producing lactotropes, are dependent on the pituitary-specific transcription factor, POU1F1. While POU1F1 is expressed in both cell types, and plays a role in activation of both the Gh and Prl genes, expression of Gh and Prl is restricted to somatotropes and lactotropes, respectively. These observations imply the existence of additional factors that contribute to the somatotrope and lactotrope identities and their hormone expressions. Prior transcriptome analysis of primary somatotropes and lactotropes isolated from the mouse pituitary identified enrichment of a transcription factor, Nr4a2, in the lactotropes. Nr4a2 was shown in a cell culture model to bind the Prl promoter at a position adjacent to Pou1f1 and to synergize with Pou1f1 in driving Prl transcription. Here we demonstrate in vivo the role of Nr4a2 as an enhancer of Prl expression by conditional gene inactivation of the Nr4a2 gene in mouse lactotropes. We demonstrate that nuclear orphan receptor transcription factor (NR4A2) binding at the Prl promoter is dependent on actions of POU1F1; while POU1F1 is essential to loading polymerase (Pol) II on the Prl promoter, Nr4a2 plays a role in enhancing Pol II release into the Prl gene body. These studies establish an in vivo role of Nr4a2 in enhancing Prl expression in mouse lactotropes, explore its mechanism of action, and establish a system for further study of the lactotrope lineage in the pituitary.