Hypopituitarism in Sox3 null mutants correlates with altered NG2-glia in the median eminence and is influenced by aspirin and gut microbiota.

The median eminence (ME), located at the base of the hypothalamus, is an essential centre of information exchange between the brain and the pituitary. We and others previously showed that mutations and duplications affecting the transcription factor SOX3/Sox3 result in hypopituitarism, and this is likely of hypothalamic origin. We demonstrate here that the absence of Sox3 predominantly affects the ME with phenotypes that first occur in juvenile animals, despite the embryonic onset of SOX3 expression. In the pituitary, reduction in hormone levels correlates with a lack of endocrine cell maturation. In parallel, ME NG2-glia renewal and oligodendrocytic differentiation potential are affected. We further show that low-dose aspirin treatment, which is known to affect NG2-glia, or changes in gut microbiota, rescue both proliferative defects and hypopituitarism in Sox3 mutants. Our study highlights a central role of NG2-glia for ME function during a transitional period of post-natal development and indicates their sensitivity to extrinsic signals.

Paracrine FGF1 signaling directs pituitary architecture and size.

Organ architecture is established during development through intricate cell-cell communication mechanisms, yet the specific signals mediating these communications often remain elusive. Here, we used the anterior pituitary gland that harbors different interdigitated hormone-secreting homotypic cell networks to dissect cell-cell communication mechanisms operating during late development. We show that blocking differentiation of corticotrope cells leads to pituitary hypoplasia with a major effect on somatotrope cells that directly contact corticotropes. Gene knockout of the corticotrope-restricted transcription factor Tpit results in fewer somatotropes, with less secretory granules and a loss of cell polarity, resulting in systemic growth retardation. Single-cell transcriptomic analyses identified FGF1 as a corticotrope-specific Tpit dosage-dependent target gene responsible for these phenotypes. Consistently, genetic ablation of FGF1 in mice phenocopies pituitary hypoplasia and growth impairment observed in Tpit-deficient mice. These findings reveal FGF1 produced by the corticotrope cell network as an essential paracrine signaling molecule participating in pituitary architecture and size.

Single-cell transcriptomic analysis reveals rich pituitary-Immune interactions under systemic inflammation.

The pituitary represents an essential hub in the hypothalamus-pituitary-adrenal (HPA) axis. Pituitary hormone-producing cells (HPCs) release several hormones to regulate fundamental bodily functions under normal and stressful conditions. It is well established that the pituitary endocrine gland modulates the immune system by releasing adrenocorticotropic hormone (ACTH) in response to neuronal activation in the hypothalamus. However, it remains unclear how systemic inflammation regulates the transcriptomic profiles of pituitary HPCs. Here, we performed single-cell RNA-sequencing (scRNA-seq) of the mouse pituitary and revealed that upon inflammation, all major pituitary HPCs respond robustly in a cell type-specific manner, with corticotropes displaying the strongest reaction. Systemic inflammation also led to the production and release of noncanonical bioactive molecules, including Nptx2 by corticotropes, to modulate immune homeostasis. Meanwhile, HPCs up-regulated the gene expression of chemokines that facilitated the communication between the HPCs and immune cells. Together, our study reveals extensive interactions between the pituitary and immune system, suggesting multifaceted roles of the pituitary in mediating the effects of inflammation on many aspects of body physiology.

Peak-agnostic high-resolution cis-regulatory circuitry mapping using single cell multiome data.

Single same cell RNAseq/ATACseq multiome data provide unparalleled potential to develop high resolution maps of the cell-type specific transcriptional regulatory circuitry underlying gene expression. We present CREMA, a framework that recovers the full cis-regulatory circuitry by modeling gene expression and chromatin activity in individual cells without peak-calling or cell type labeling constraints. We demonstrate that CREMA overcomes the limitations of existing methods that fail to identify about half of functional regulatory elements which are outside the called chromatin 'peaks'. These circuit sites outside called peaks are shown to be important cell type specific functional regulatory loci, sufficient to distinguish individual cell types. Analysis of mouse pituitary data identifies a Gata2-circuit for the gonadotrope-enriched disease-associated Pcsk1 gene, which is experimentally validated by reduced gonadotrope expression in a gonadotrope conditional Gata2-knockout model. We present a web accessible human immune cell regulatory circuit resource, and provide CREMA as an R package.

Epigenetic control of adaptive or homeostatic splicing during interval-training activities.

Interval-training activities induce adaptive cellular changes without altering their fundamental identity, but the precise underlying molecular mechanisms are not fully understood. In this study, we demonstrate that interval-training depolarization (ITD) of pituitary cells triggers distinct adaptive or homeostatic splicing responses of alternative exons. This occurs while preserving the steady-state expression of the Prolactin and other hormone genes. The nature of these splicing responses depends on the exon's DNA methylation status, the methyl-C-binding protein MeCP2 and its associated CA-rich motif-binding hnRNP L. Interestingly, the steady expression of the Prolactin gene is also reliant on MeCP2, whose disruption leads to exacerbated multi-exon aberrant splicing and overexpression of the hormone gene transcripts upon ITD, similar to the observed hyperprolactinemia or activity-dependent aberrant splicing in Rett Syndrome. Therefore, epigenetic control is crucial for both adaptive and homeostatic splicing and particularly the steady expression of the Prolactin hormone gene during ITD. Disruption in this regulation may have significant implications for the development of progressive diseases.

The First Pituitary Proteome Landscape From Matched Anterior and Posterior Lobes for a Better Understanding of the Pituitary Gland.

To date, very few mass spectrometry (MS)-based proteomics studies are available on the anterior and posterior lobes of the pituitary. In the past, MS-based investigations have focused exclusively on the whole pituitary gland or anterior pituitary lobe. In this study, for the first time, we performed a deep MS-based analysis of five anterior and five posterior matched lobes to build the first lobe-specific pituitary proteome map, which documented 4090 proteins with isoforms, mostly mapped into chromosomes 1, 2, and 11. About 1446 differentially expressed significant proteins were identified, which were studied for lobe specificity, biological pathway enrichment, protein-protein interaction, regions specific to comparison of human brain and other neuroendocrine glands from Human Protein Atlas to identify pituitary-enriched proteins. Hormones specific to each lobe were also identified and validated with parallel reaction monitoring-based target verification. The study identified and validated hormones, growth hormone and thyroid-stimulating hormone subunit beta, exclusively to the anterior lobe whereas oxytocin-neurophysin 1 and arginine vasopressin to the posterior lobe. The study also identified proteins POU1F1 (pituitary-specific positive transcription factor 1), POMC (pro-opiomelanocortin), PCOLCE2 (procollagen C-endopeptidase enhancer 2), and NPTX2 (neuronal pentraxin-2) as pituitary-enriched proteins and was validated for their lobe specificity using parallel reaction monitoring. In addition, three uPE1 proteins, namely THEM6 (mesenchymal stem cell protein DSCD75), FSD1L (coiled-coil domain-containing protein 10), and METTL26 (methyltransferase-like 26), were identified using the NeXtProt database, and depicted tumor markers S100 proteins having high expression in the posterior lobe. In summary, the study documents the first matched anterior and posterior pituitary proteome map acting as a reference control for a better understanding of functional and nonfunctional pituitary adenomas and extrapolating the aim of the Human Proteome Project towards the investigation of the proteome of life.

Pituitary transcriptome profile from laying period to incubation period of Changshun green-shell laying hens.

BACKGROUND: Incubation behaviour, an instinct for natural breeding in poultry, is strictly controlled by the central nervous system and multiple neuroendocrine hormones and neurotransmitters, and is closely associated with the cessation of egg laying. Therefore, it is essential for the commercial poultry industry to clarify the molecular regulation mechanism of incubation behaviour. Here, we used high-throughput sequencing technology to examine the pituitary transcriptome of Changshun green-shell laying hen, a local breed from Guizhou province, China, with strong broodiness, in two reproductive stages, including egg-laying phase (LP) and incubation phase (BP). We also analyze the differences in gene expression during the transition from egg-laying to incubation, and identify critical pathways and candidate genes involved in controlling the incubation behaviour in the pituitary. RESULTS: In this study, we demonstrated that a total of 2089 differently expressed genes (DEGs) were identified in the pituitary, including 842 up-regulated and 1247 down-regulated genes. Kyoto Encyclopedia of Genes and Genomes (KEGG) analysis revealed that steroid biosynthesis pathway and neuroactive ligand-receptor interaction were significantly enriched based on DEGs commonly identified in pituitary. Further analysis revealed that SRC, ITGB4, ITGB3, PIK3R3 and DRD2 may play crucial roles in the regulation of incubation behaviour. CONCLUSIONS: We identified 2089 DEGs and the key signaling pathways which may be closely correlated with incubation in Changshun green-shell laying hens, and clarified the molecular regulation mechanism of incubation behaviour. Our results indicate the complexity and variety of differences in reproductive behaviour of different chicken breeds.

Key mRNAs and lncRNAs of pituitary that affect the reproduction of FecB + + small tail han sheep.

BACKGROUND: The pituitary directly regulates the reproductive process through follicle-stimulating hormone (FSH) and luteinizing hormone (LH). Transcriptomic research on the pituitaries of ewes with different FecB (fecundity Booroola) genotypes has shown that some key genes and lncRNAs play an important role in pituitary function and sheep fecundity. Our previous study found that ewes with FecB + + genotypes (without FecB mutation) still had individuals with more than one offspring per birth. It is hoped to analyze this phenomenon from the perspective of the pituitary transcriptome. RESULTS: The 12 Small Tail Han Sheep were equally divided into polytocous sheep in the follicular phase (PF), polytocous sheep in the luteal phase (PL), monotocous sheep in the follicular phase (MF), and monotocous sheep in the luteal phase (ML). Pituitary tissues were collected after estrus synchronous treatment for transcriptomic analysis. A total of 384 differentially expressed genes (DEGs) (182 in PF vs. MF and 202 in PL vs. ML) and 844 differentially expressed lncRNAs (DELs) (427 in PF vs. MF and 417 in PL vs. ML) were obtained from the polytocous-monotocous comparison groups in the two phases. Functional enrichment analysis showed that the DEGs in the two phases were enriched in signaling pathways known to play an important role in sheep fecundity, such as calcium ion binding and cAMP signaling pathways. A total of 1322 target relationship pairs (551 pairs in PF vs. MF and 771 pairs in PL vs. ML) were obtained for the target genes prediction of DELs, of which 29 DEL-DEG target relationship pairs (nine pairs in PF vs. MF and twenty pairs in PL vs. ML). In addition, the competing endogenous RNA (ceRNA) networks were constructed to explore the regulatory relationships of DEGs, and some important regulatory relationship pairs were obtained. CONCLUSION: According to the analysis results, we hypothesized that the pituitary first receives steroid hormone signals from the ovary and uterus and that VAV3 (Vav Guanine Nucleotide Exchange Factor 3), GABRG1 (Gamma-Aminobutyric Acid A Receptor, Gamma 1), and FNDC1 (Fibronectin Type III Domain Containing 1) played an important role in this process. Subsequently, the reproductive process was regulated by gonadotropins, and IGFBP1 (Insulin-like Growth Factor Binding Protein 1) was directly involved in this process, ultimately affecting litter size. In addition, TGIF1 (Transforming Growth Factor-Beta-Induced Factor 1) and TMEFF2 (Transmembrane Protein With EGF Like And Two Follistatin Like Domains 2) compensated for the effect of the FecB mutation and function by acting on TGF-ß/SMAD signaling pathway, an important pathway for sheep reproduction. These results provided a reference for understanding the mechanism of multiple births in Small Tail Han Sheep without FecB mutation.

Neuregulin 4 (Nrg4) cooperates with melatonin to regulate the PRL expression via ErbB4/Erk signaling pathway as a potential prolactin (PRL) regulator.

Neuregulin-4 (Nrg4) and melatonin play vital roles in endocrine diseases. However, there is little discussion about the function and potential mechanism of Nrg4 and melatonin in prolactin (PRL) regulation. The human normal pituitary data from Gene Expression Profiling Interactive Analysis (GEPIA) database was used to explore the correlation between NRG4 and PRL. The expression and correlation of NRG4 and PRL were determined by Immunofluorescence staining (IF) and human normal pituitary tissue microarray. Western Blot (WB) was used to detect the expression of PRL, p-ErbB2/3/4, ErbB2/3/4, p-Erk1/2, Erk1/2, p-Akt and Akt in PRL-secreting pituitary GH3 and RC-4B/C cells treated by Nrg4, Nrg4-small interfering RNA, Erk1/2 inhibitor FR180204 and melatonin. The expression of NRG4 was significantly positively correlated with that of PRL in the GEPIA database and normal human pituitary tissues. Nrg4 significantly increased the expression and secretion of PRL and p-Erk1/2 expression in GH3 cells and RC-4B/C cells. Inhibition of Nrg4 significantly inhibited PRL expression. The increased levels of p-Erk1/2 and PRL induced by Nrg4 were abolished significantly in response to FR180204 in GH3 and RC-4B/C cells. Additionally, Melatonin promotes the expression of Nrg4, p-ErbB4, p-Erk1/2, and PRL and can further promote the expression of p-Erk1/2 and PRL in combination with Nrg4. Further investigation into the function of Nrg4 and melatonin on PRL expression and secretion may provide new clues to advance the clinical control of prolactinomas and hyperprolactinemia.

A dynamic and mosaic basement membrane controls cell intercalation in Drosophila ovaries.

Basement membranes (BM) are extracellular matrices assembled into complex and highly organized networks essential for organ morphogenesis and function. However, little is known about the tissue origin of BM components and their dynamics in vivo Here, we unravel the assembly and role of the BM main component, Collagen type IV (ColIV), in Drosophila ovarian stalk morphogenesis. Stalks are short strings of cells assembled through cell intercalation that link adjacent follicles and maintain ovarian integrity. We show that stalk ColIV has multiple origins and is assembled following a regulated pattern leading to a unique BM organisation. Absence of ColIV leads to follicle fusion, as observed upon ablation of stalk cells. ColIV and integrins are both required to trigger cell intercalation and maintain mechanically strong cell-cell attachment within the stalk. These results show how the dynamic assembly of a mosaic BM controls complex tissue morphogenesis and integrity.

IGFBP1a is a nutrient deficient response factor that can inhibit fish reproduction through the hypothalamus-pituitary-ovary axis†.

Reproduction is a high energy consuming process, so long-term malnutrition can significantly inhibit gonadal development. However, little is known about the molecular mechanism by which fasting inhibits reproduction. Our present study found that fasting could dramatically induce insulin-like growth factor binding protein 1 (IGFBP1) expression in the liver, hypothalamus, pituitary and ovaries of grass carp. In addition, IGFBP1a in the hypothalamus-pituitary-gonad axis could inhibit the development of gonads. These results indicated that fasting may participate in the regulation of fish gonadal development through the mediation of IGFBP1a. Further studies found that IGFBP1a could markedly inhibit gonadotropin-releasing hormone 3 expressions in hypothalamus cells. At the pituitary level, IGFBP1a could significantly reduce the gonadotropin hormones (LH and FSH) expression by blocking the action of pituitary insulin-like growth factor 1. Interestingly, IGFBP1a could also directly inhibit the expression of lhr, fshr, and sex steroid hormone synthase genes (cyp11a, cyp17a, and cyp19a1) in the ovary. These results indicated that IGFBP1a should be a nutrient deficient response factor that could inhibit fish reproduction through the hypothalamus-pituitary-ovary axis.

The influence of body composition on the response to dynamic stimulation of the endocrine pituitary-testis axis.

BACKGROUND: Testosterone treatment is generally not recommended in men with obesity induced low serum testosterone. However, distinguishing this condition from overt testosterone deficiency in men with obesity where treatment should be initiated is a diagnostic challenge and tools to differentiate these conditions are scarce but could be of important clinical relevance. OBJECTIVES: To investigate the association between body composition and dynamic responses of the pituitary-testis axis in men. METHODS: Single-center cross-sectional study including 112 healthy men. Participants went through a full biochemical assessment of the pituitary-testis axis, and dynamic stimulatory tests of luteinizing hormone (LH) secretion (gonadotropin-releasing hormone (GnRH)-test) and testosterone secretion (choriogonadotropin (hCG)-test). A subset (N = 78) further had a DXA-scan performed. RESULTS: A higher body mass index (BMI) was associated with lower basal serum LH (BU = -0.44, 95% CI: -0.88--0.01, p = 0.04). The GnRH-stimulated LH increase was not significantly associated with BMI (BU = -0.10, 95% CI: -0.72-0.51, p = 0.74). Furthermore, a high BMI was associated with low basal testosterone (BU -0.02, 95% CI: -0.03--0.02, p < 0.001), and free testosterone (BU -15.0, 95% CI: -19.9--10.0, p < 0.001) and men with overweight and obesity had significantly lower testosterone (9%, p = 0.003 and 24%, p < 0.001) and free testosterone (25%, p = 0.006 and 50%, p < 0.001) concentrations compared to men with normal weight. The HCG-stimulated testosterone increase was significantly less dependent on BMI compared to the influence of BMI on basal testosterone concentrations (p = 0.04 for the interaction). CONCLUSIONS: Dynamic sex hormone responses following pituitary-testis axis stimulation were less dependent on BMI, compared to the influence of BMI on basal hormone concentrations and could potentially assist clinical decision making in patients with obesity suspected of testosterone deficiency.

The saccus vasculosus of the neotropical cichlid fish Cichlasoma dimerus: characterization, developmental studies and its response to photoperiod.

The saccus vasculosus is an organ present in gnathostome fishes, located ventral to the hypothalamus and posterior to the pituitary gland, whose structure is highly variable among species. In some fishes, this organ is well-developed; however, its physiological function is still under debate. Recently, it has been proposed that this organ is a seasonal regulator of reproduction. In the present work, we examined the histology, ultrastructure, and development of the saccus vasculosus in Cichlasoma dimerus. In addition, immunohistochemical studies of proteins related to reproductive function were performed. Finally, the potential response of this organ to different photoperiods was explored. C. dimerus presented a well-developed saccus vasculosus consisting of a highly folded epithelium, composed of coronet and supporting cells, closely associated with blood vessels, and a highly branched lumen connected to the third ventricle. Coronet cells showed all the major characteristics described in other fish species. In addition, some of the vesicles of the globules were positive for thyrotropin beta subunit, while luteinizing hormone beta subunit immunostaining was observed at the edge of the apical processes of some coronet cells. Furthermore, neuropeptide Y and gonadotropin inhibitory hormone innervation in the saccus vasculosus of C. dimerus were shown. Finally, animals exposed to the long photoperiod showed lower levels of thyrotropin beta and common alpha subunits expression in the saccus compared to those of animals exposed to short photoperiod. All these results support the hypothesis that the saccus vasculosus is involved in the regulation of reproductive function in fish.

The Fuzzy planar cell polarity protein (FUZ), necessary for primary cilium formation, is essential for pituitary development.

The primary cilium is an essential organelle that is important for normal cell signalling during development and homeostasis but its role in pituitary development has not been reported. The primary cilium facilitates signal transduction for multiple pathways, the best-characterised being the SHH pathway, which is known to be necessary for correct pituitary gland development. FUZ is a planar cell polarity (PCP) effector that is essential for normal ciliogenesis, where the primary cilia of Fuz-/- mutants are shorter or non-functional. FUZ is part of a group of proteins required for recruiting retrograde intraflagellar transport proteins to the base of the organelle. Previous work has reported ciliopathy phenotypes in Fuz-/- homozygous null mouse mutants, including neural tube defects, craniofacial abnormalities, and polydactyly, alongside PCP defects including kinked/curly tails and heart defects. Interestingly, the pituitary gland was reported to be missing in Fuz-/- mutants at 14.5 dpc but the mechanisms underlying this phenotype were not investigated. Here, we have analysed the pituitary development of Fuz-/- mutants. Histological analyses reveal that Rathke's pouch (RP) is initially induced normally but is not specified and fails to express LHX3, resulting in hypoplasia and apoptosis. Characterisation of SHH signalling reveals reduced pathway activation in Fuz-/- mutant relative to control embryos, leading to deficient specification of anterior pituitary fate. Analyses of the key developmental signals FGF8 and BMP4, which are influenced by SHH, reveal abnormal patterning in the ventral diencephalon, contributing further to abnormal RP development. Taken together, our analyses suggest that primary cilia are required for normal pituitary specification through SHH signalling.

Intracerebroventricular injection of kisspeptin in male rats activates hypothalamo-pituitary-gonadal axis, but not hypothalamo-pituitary-adrenal axis.

Kisspeptin is an important hormone involved in the stimulation of the hypothalamo-pituitary gonadal (HPG) axis. The HPG axis can be suppressed in certain conditions such as stress, which gives rise to the activation of the hypothalamo-pituitary-adrenal (HPA) axis. However, the physiological role of kisspeptin in the interaction of HPG and HPA axis is not fully understood yet. This study was conducted to investigate the possible effects of central kisspeptin injection on HPG axis as well as HPA axis activity. Adult male Wistar rats were randomly divided into seven groups as followed: sham (control), kisspeptin (50 pmol), P234 (1 nmol), kisspeptin + p234, kisspeptin + antalarmin (0.1 µg), kisspeptin + astressin 2B (1 µg), and kisspeptin + atosiban (300 ng/rat) (n = 10 each group). At the end of the experiments, the hypothalamus, pituitary, and serum samples of the rats were collected. There was no significant difference in corticotropic-releasing hormone immunoreactivity in the paraventricular nucleus of the hypothalamus, serum adrenocorticotropic hormone, and corticosterone levels among all groups. Moreover, no significant difference was detected in pituitary oxytocin level. Serum follicle-stimulating hormone and luteinizing hormone levels of the kisspeptin, kisspeptin + antalarmin, and kisspeptin + astressin 2B groups were significantly higher than the control group. Serum testosterone levels were significantly higher in the kisspeptin kisspeptin + antalarmin, kisspeptin + astressin 2B, and kisspeptin + atosiban groups compared to the control group. Our findings suggest that central kisspeptin injection causes activation in the HPG axis, but not the HPA axis in male rats.

Exposure to topiramate and acetazolamide causes endocrine disrupting effects in female rats during estrus.

BACKGROUND: Idiopathic intracranial hypertension (IIH) is a disease characterized by elevated intracranial pressure (ICP) and is a disease of young females. The first line pharmacological treatments include acetazolamide and topiramate and given the nature of IIH patients and the dosing regimen of these drugs, their effect on the endocrine system is important to evaluate. We aimed to assess the effects of acetazolamide and topiramate on steroid profiles in relevant endocrine tissues. METHODS: Female Sprague Dawley rats received chronic clinically equivalent doses of acetazolamide or topiramate by oral gavage and were sacrificed in estrus. Tissue specific steroid profiles of lateral ventricle CP, 4th ventricle CP, CSF, serum, uterine horn and fundus, ovaries, adrenal glands and pituitary glands were assessed by quantitative targeted LC-MS/MS. We determined luteinizing hormone (LH) and follicle stimulating hormones (FSH) levels in paired serum by ELISA. RESULTS: Topiramate increased the concentration of estradiol and decreased the concentration of DHEA in lateral choroid plexus. Moreover, it decreased the concentration of androstenediol in the pituitary gland. Topiramate increased serum LH. Acetazolamide decreased progesterone levels in serum and uterine fundus and increased corticosteroid levels in the adrenal glands. CONCLUSION: These results demonstrate that both acetazolamide and topiramate have endocrine disrupting effects in rats. Topiramate primarily targeted the choroid plexus and the pituitary gland while acetazolamide had broader systemic effects. Furthermore, topiramate predominantly targeted sex hormones, whereas acetazolamide widely affected all classes of hormones. A similar effect in humans has not yet been documented but these concerning findings warrants further investigations.

Acute stress modulates the outcome of traumatic brain injury-associated gene expression and behavioral responses.

Psychological stress and traumatic brain injury (TBI) result in long-lasting emotional and behavioral impairments in patients. So far, the interaction of psychological stress with TBI not only in the brain but also in peripheral organs is poorly understood. Herein, the impact of acute stress (AS) occurring immediately before TBI is investigated. For this, a mouse model of restraint stress and TBI was employed, and their influence on behavior and gene expression in brain regions, the hypothalamic-pituitary-adrenal (HPA) axis, and peripheral organs was analyzed. Results demonstrate that, compared to single AS or TBI exposure, mice treated with AS prior to TBI showed sex-specific alterations in body weight, memory function, and locomotion. The induction of immediate early genes (IEGs, e.g., c-Fos) by TBI was modulated by previous AS in several brain regions. Furthermore, IEG upregulation along the HPA axis (e.g., pituitary, adrenal glands) and other peripheral organs (e.g., heart) was modulated by AS-TBI interaction. Proteomics of plasma samples revealed proteins potentially mediating this interaction. Finally, the deletion of Atf3 diminished the TBI-induced induction of IEGs in peripheral organs but left them largely unaltered in the brain. In summary, AS immediately before brain injury affects the brain and, to a strong degree, also responses in peripheral organs.

Single-Cell RNA Sequencing and Its Applications in Pituitary Research.

BACKGROUND: Mounting evidence underscores the significance of cellular diversity within the endocrine system and the intricate interplay between different cell types and tissues, essential for preserving physiological balance and influencing disease trajectories. The pituitary gland, a central player in the endocrine orchestra, exemplifies this complexity with its assortment of hormone-secreting and nonsecreting cells. SUMMARY: The pituitary gland houses several types of cells responsible for hormone production, alongside nonsecretory cells like fibroblasts and endothelial cells, each playing a crucial role in the gland's function and regulatory mechanisms. Despite the acknowledged importance of these cellular interactions, the detailed mechanisms by which they contribute to pituitary gland physiology and pathology remain largely uncharted. The last decade has seen the emergence of groundbreaking technologies such as single-cell RNA sequencing, offering unprecedented insights into cellular heterogeneity and interactions. However, the application of this advanced tool in exploring the pituitary gland's complexities has been scant. This review provides an overview of this methodology, highlighting its strengths and limitations, and discusses future possibilities for employing it to deepen our understanding of the pituitary gland and its dysfunction in disease states. KEY MESSAGE: Single-cell RNA sequencing technology offers an unprecedented means to study the heterogeneity and interactions of pituitary cells, though its application has been limited thus far. Further utilization of this tool will help uncover the complex physiological and pathological mechanisms of the pituitary, advancing research and treatment of pituitary diseases.

Collagen XIII Is the Key Molecule of Neurovascular Junctions in the Neuroendocrine System.

INTRODUCTION: Axons of magnocellular neurosecretory cells project from the hypothalamus to the posterior lobe (PL) of the pituitary. In the PL, a wide perivascular space exists between the outer basement membrane (BM), where nerve axons terminate, and the inner BM lining the fenestrated capillaries. Hypothalamic axon terminals and outer BMs in the PL form neurovascular junctions. We previously had found that collagen XIII is strongly localized in the outer BMs. In this study, we investigated the role of collagen XIII in the PL of rat pituitaries. METHODS: We first studied the expression of Col13a1, the gene encoding the α1 chains of collagen XIII, in rat pituitaries via quantitative real-time polymerase chain reaction and in situ hybridization. We observed the distribution of COL13A1 in the rat pituitary using immunohistochemistry and immunoelectron microscopy. We examined the expression of Col13a1 and the distribution of COL13A1 during the development of the pituitary. In addition, we examined the effects of water deprivation and arginine vasopressin (AVP) signaling on the expression of Col13a1 in the PL. RESULTS: Col13a1 was expressed in NG2-positive pericytes, and COL13A1 signals were localized in the outer BM of the PL. The expression of Col13a1 was increased by water deprivation and was regulated via the AVP/AVPR1A/Gαq/11 cascade in pericytes of the PL. CONCLUSION: These results suggest that pericytes surrounding fenestrated capillaries in the PL secrete COL13A1 and are involved in the construction of neurovascular junctions. COL13A1 is localized in the outer BM surrounding capillaries in the PL and may be involved in the connection between capillaries and axon terminals.

Morphological identification and distribution comparison of telocytes in pituitary gland between normal and cryptorchid yaks.

BACKGROUND: Telocytes (TCs) is a novel type of interstitial cells in many mammals organs, which participate in the organizational metabolism, mechanical support, immunomodulation and other aspects. The aim of this study was to explore the organizational chemical characteristics of TCs in pituitary gland and their changes in cryptorchid yaks. METHODS: Transmission electron microscopy (TEM), toluidine blue staining, immunofluorescence, qRT-PCR, and Western blotting may enable us to understand TCs distribution characteristics and biological functions. RESULT: TEM confirmed the presence of TCs in the pituitary gland with small bodies and moniliform telopodes (Tps). The Tps extending out from the cell body to the peri-sinusoidal vessels spaces, the number of Tps is closely related to the morphology of the nucleus. The most obvious changes of TCs in the pituitary gland of cryptorchid yaks is the Tps are relatively shorter and decreased secretory vesicles. H.E. and toluidine blue staining revealed that TCs not only distributed between the sinusoidal blood vessels and the glandular cell clusters, but also present on the surface of vascular endothelial cells. The co-expression of TCs biomarkers, such as Vimentin/CD34, CD117/CD34 and α-SMA/CD34, were evaluated by immunofluorescence to further determine the phenotypic characteristics of TCs. Besides, we analyzed the mRNA and protein expression of these biomarkers to determine the characteristics of TCs changes and possible biological roles. Both the mRNA and protein expression of CD117 were significantly higher in the pituitary gland of cryptorchid yaks than in the normal (p < 0.01), the protein expression of CD34 in the cryptorchid yaks was significantly higher than the normal (p < 0.01). There were no significant difference in mRNA expression of Vimentin and α-SMA (p>0.05), while the protein expression were significantly increased in the normal yaks (p < 0.05). CONCLUSIONS: In summary, this study reports for the first time that the biological characteristics of TCs in yak pituitary gland. Although there is no significant change in the distribution characteristics, the changes in biological features of TCs in cryptorchid yaks are clear, suggesting that TCs participated in alteration in the local microenvironment of the pituitary gland. Therefore, our study provides clues for further investigating the role of TCs in the pituitary gland during the occurrence of cryptorchidism in yaks.