The roles of androgens in male reproductive development and function in zebrafish are poorly understood. To investigate this topic we employed CRISPR/Cas9 to generate cyp11c1 (11β-hydroxylase) mutant zebrafish lines. Our study confirms recently published findings from a different cyp11c1-/- mutant zebrafish line, and also reports novel aspects of the phenotype caused by loss of Cyp11c1 function. We report that Cyp11c1-deficient zebrafish display predominantly female secondary sex characteristics, but may possess either ovaries or testes. Moreover, we observed that cyp11c1-/- mutant male zebrafish are profoundly androgen- and cortisol-deficient. These results provide further evidence that androgens are dispensable for testis formation in zebrafish, as has been demonstrated previously in androgen-deficient and androgen-resistant zebrafish. Herein, we show that the testes of cyp11c1-/- mutant zebrafish exhibit a disorganised tubular structure; and for the first time demonstrate that the spermatic ducts, which connect the testes to the urogenital orifice, are severely hypoplastic in androgen-deficient zebrafish. Furthermore, we show that spermatogenesis and characteristic breeding behaviours are impaired in cyp11c1-/- mutant zebrafish. Expression of nanos2, a type A spermatogonia marker, was significantly increased in the testes of Cyp11c1-deficient zebrafish, whereas expression of markers for later stages of spermatogenesis was significantly decreased. These observations indicate that in zebrafish, production of type A spermatogonia is androgen-independent, but differentiation of type A spermatogonia is an androgen-dependent process. Overall, our results demonstrate that whilst androgens are not required for testis formation, they play important roles in determining secondary sexual characteristics, proper organisation of seminiferous tubules, and differentiation of male germ cells.
James A Oakes, Lise Barnard, Karl-Heinz Storbeck, Vincent T Cunliffe, and Nils P Krone
Bushra Taqui, Farzad Asadi, Evangelina Capobianco, Daniel Barry Hardy, Alicia Jawerbaum, and Edith Juliana Arany
Maternal diabetes impairs fetal development and increases the risk of metabolic diseases in the offspring. Previously, we demonstrated that maternal dietary supplementation with 6% of olive oil prevents diabetes-induced embryo and fetal defects, in part, through the activation of peroxisome proliferator-activated receptors (PPARs). In this study, we examined the effects of this diet on neonatal and adult pancreatic development in male and female offspring of mothers affected with pre-gestational diabetes. A mild diabetic model was developed by injecting neonatal rats with streptozotocin (90 mg/kg). During pregnancy, these dams were fed a chow diet supplemented or not with 6% olive oil. Offspring pancreata was examined at day 2 and 5 months of age by immunohistochemistry followed by morphometric analysis to determine number of islets, α and β cell clusters and β-cell mass. At 5 months, male offspring of diabetic mothers had reduced β-cell mass that was prevented by maternal supplementation with olive oil. PPARα and PPARγ were localized mainly in α cells and PPARβ/δ in both α and β cells. Although Pparβ/δ and Pparγ RNA expression showed reduction in 5-month-old male offspring of diabetic rats, Pparβ/δ expression returned to control levels after olive-oil supplementation. Interestingly, in vitro exposure to oleic acid (major component of olive oil) and natural PPAR agonists such as LTB4, CPC and 15dPGJ2 also significantly increased expression of all Ppars in αTC1–6 cells. However, only oleic acid and 15dPGJ2 increased insulin and Pdx-1 expression in INS-1E cells suggesting a protective role in β-cells. Olive oil may be considered a dietary supplement to improve islet function in offspring of affected mothers with pre-gestational diabetes.
Chaoyi Zhang, Qianli Zhang, Zhihong Huang, and Quan Jiang
Adropin plays a role in the maintenance of energy homeostasis, insulin resistance prevention, and impaired glucose tolerance. However, the molecular mechanisms by which adropin affects hepatic glucose and lipid metabolism in vitro are not entirely understood. This study intended to examine the roles and underlying mechanisms of adropin in glucose and lipid metabolism in Nile tilapia. In primary cultured tilapia hepatocytes, adropin significantly attenuated oleic acid (OA)-induced glucose output and reduced the activities and mRNA expression of cytosolic phosphoenolpyruvate carboxykinase (PEPCK) and glucose-6-phosphatase (G6Pase), which are involved in gluconeogenesis. In contrast, adropin facilitated glucose uptake activity via glucose transporter 1 (Glut1) upregulation in OA-treated hepatocytes. One-week of adropin treatment reduced the hepatic total lipid accumulation in OA-fed tilapia without changes in body weight. Subsequent studies revealed that adropin suppressed OA-induced intracellular triglyceride accumulation and decreased the expression of genes and proteins involved in lipid metabolisms such as sterol regulatory element-binding protein-1c (SREBP-1c), acetyl-CoA carboxylase α (ACCα) and CD36, but upregulated peroxisome proliferator-activated receptor α (PPARα) levels. In parallel studies, however, adropin had no detectable effects on fatty acid-binding protein 4 (Fabp4) and carnitine palmitoyltransferase 1α (Cpt1α) mRNA expression. Furthermore, adropin treatment dose-dependently increased the phosphorylation level of AMP-activated protein kinase (AMPK). Suppression of AMPK by compound C or AMPKα1 siRNA blocked adropin-induced decreases in the mature form of SREBP-1c expression, glucose output, and intracellular triglyceride content in OA-treated hepatocytes. These findings suggest that teleost adropin could suppress hepatic gluconeogenesis and triglyceride accumulation via a mechanism dependent on AMPK signalling.
Qinglei Yin, Liyun Shen, Yicheng Qi, Dalong Song, Lei Ye, Ying Peng, Yanqiu Wang, Zhou Jin, Guang Ning, Weiqing Wang, Dongping Lin, and Shu Wang
SIRT1, a class III histone/protein deacetylase (HDAC), has been associated with autoimmune diseases. There is a paucity of data about the role of SIRT1 in Graves’ disease. The aim of this study was to investigate the role of SIRT1 in the pathogenesis of GD. Here, we showed that SIRT1 expression and activity were significantly decreased in GD patients compared with healthy controls. The NF-κB pathway was activated in the peripheral blood of GD patients. The reduced SIRT1 levels correlated strongly with clinical parameters. In euthyroid patients, SIRT1 expression was markedly upregulated and NF-κB downstream target gene expression was significantly reduced. SIRT1 inhibited the NF-κB pathway activity by deacetylating P65. These results demonstrate that reduced SIRT1 expression and activity contribute to the activation of the NF-κB pathway and may be involved in the pathogenesis of GD.
Pauline Campos, Jamie J Walker, and Patrice Mollard
In most species, survival relies on the hypothalamic control of endocrine axes that regulate critical functions such as reproduction, growth, and metabolism. For decades, the complexity and inaccessibility of the hypothalamic–pituitary axis has prevented researchers from elucidating the relationship between the activity of endocrine hypothalamic neurons and pituitary hormone secretion. Indeed, the study of central control of endocrine function has been largely dominated by ‘traditional’ techniques that consist of studying in vitro or ex vivo isolated cell types without taking into account the complexity of regulatory mechanisms at the level of the brain, pituitary and periphery. Nowadays, by exploiting modern neuronal transfection and imaging techniques, it is possible to study hypothalamic neuron activity in situ, in real time, and in conscious animals. Deep-brain imaging of calcium activity can be performed through gradient-index lenses that are chronically implanted and offer a ‘window into the brain’ to image multiple neurons at single-cell resolution. With this review, we aim to highlight deep-brain imaging techniques that enable the study of neuroendocrine neurons in awake animals whilst maintaining the integrity of regulatory loops between the brain, pituitary and peripheral glands. Furthermore, to assist researchers in setting up these techniques, we discuss the equipment required and include a practical step-by-step guide to performing these deep-brain imaging studies.
Isabelle Lee, Guannan Zhang, Clementina Mesaros, and Trevor M Penning
Polycyclic aromatic hydrocarbons (PAHs) are environmental pollutants generated from the incomplete combustion of organic material. PAHs have been studied as genotoxicants, but some also act via non-genotoxic mechanisms in estrogen dependent maglinancies, such as breast cancer. PAHs require metabolic activation to electrophilic metabolites to exert their genotoxicity but non-genotoxic properties may also contribute to their carcinogenicity. The role of PAHs in endometrial cancer, a cancer associated with unopposed estrogen action is unknown. We assessed the metabolism of the representative PAH, benzo[a]pyrene (B[a]P), to estrogenic compounds in Ishikawa human endometrial cells in the presence and absence of cytochrome P450 induction. Using stable-isotope dilution high performance liquid chromatography and APCI tandem mass spectrometry in the selected reaction monitoring mode, we analyzed B[a]P metabolism in Ishikawa cells. Estrogenic activity of B[a]P metabolites was determined by the endogenous estrogen inducible alkaline phosphatase reporter gene and an exogenous estrogen response element (ERE) luciferase reporter gene construct. We also assessed whether PAHs can induce a proliferative phenotype via estrogen receptor (ER)- and non-ER-regulated pathways. We demonstrate that, B[a]P can be metabolized in human endometrial cells into 3-OH-B[a]P and B[a]P-7,8-dione in sufficient amounts to activate ERs. We also show that only B[a]P-7,8-dione induces endometrial cell proliferation at concentrations lower than required to activate the ER, instead non-genomic signaling by the epidermal growth factor receptor (EGFR) and activation of the mitogen-activated protein kinase (MAPK) pathway was responsible. This work indicates that human endometrial cells can metabolize PAHs into estrogenic metabolites which may induce cell proliferation through non-ER-regulated pathways.
Marianna Minnetti, Valeria Hasenmajer, Riccardo Pofi, Mary Anna Venneri, Krystallenia I Alexandraki, and Andrea M Isidori
The circadian rhythm derives from the integration of many signals that shape the expression of clock-related genes in a 24-h cycle. Biological tasks, including cell proliferation, differentiation, energy storage, and immune regulation, are preferentially confined to specific periods. A gating system, supervised by the central and peripheral clocks, coordinates the endogenous and exogenous signals and prepares for transition to activities confined to periods of light or darkness. The fluctuations of cortisol and its receptor are crucial in modulating these signals. Glucocorticoids and the autonomous nervous system act as a bridge between the suprachiasmatic master clock and almost all peripheral clocks. Additional peripheral synchronizing mechanisms including metabolic fluxes and cytokines stabilize the network. The pacemaker is amplified by peaks and troughs in cortisol and their response to food, activity, and inflammation. However, when the glucocorticoid exposure pattern becomes chronically flattened at high- (as in Cushing’s syndrome) or low (as in adrenal insufficiency) levels, the system fails. While endocrinologists are well aware of cortisol rhythm, too little attention has been given to interventions aimed at restoring physiological cortisol fluctuations in adrenal disorders. However, acting on glucocorticoid levels may not be the only way to restore clock-related activities. First, a counterregulatory mechanism on the glucocorticoid receptor itself controls signal transduction, and second, melatonin and/or metabolically active drugs and nutrients could also be used to modulate the clock. All these aspects are described herein, providing some insights into the emerging role of chronopharmacology, focusing on glucocorticoid excess and deficiency disorders.
Yuriko Sakai, Hideyuki Arie, Yinhua Ni, Fen Zhuge, Liang Xu, Guanliang Chen, Naoto Nagata, Takuya Suzuki, Shuichi Kaneko, Tsuguhito Ota, and Mayumi Nagashimada
Intestinal mucosal barrier dysfunction is closely related to the pathogenesis of nonalcoholic steatohepatitis (NASH). Gut immunity has been recently demonstrated to regulate gut barrier function. The Lactobacillus pentosus strain S-PT84 activates helper T cells and natural killer/natural killer T cells. In this study, we examined the effect of S-PT84 on NASH progression induced by high-cholesterol/high-fat diet (CL), focusing on the immune responses involved in gut barrier function. C57BL/6 mice were fed a normal chow or CL diet with or without 1 × 1010 S-PT84 for 22 weeks. S-PT84 administration improved hepatic steatosis by decreasing triglyceride and free fatty acid levels by 34% and 37%, respectively. Furthermore, S-PT84 inhibited the development of hepatic inflammation and fibrosis, suppressed F4/80+ macrophage/Kupffer cell infiltration, and reduced liver hydroxyproline content. Administration of S-PT84 alleviated hyperinsulinemia and enhanced hepatic insulin signalling. Compared with mice fed CL diet, mice fed CL+S-PT84 had 71% more CD11c-CD206+ M2 macrophages, resulting in a significantly decreased M1/M2 macrophage ratio in the liver. Moreover, S-PT84 inhibited the CL diet-mediated increase in intestinal permeability. Additionally, S-PT84 reduced the recruitment of interleukin-17-producing T cells and increased the levels of intestinal tight junction proteins, including zonula occludens-1, occludin, claudin-3, and claudin-7. In conclusion, our findings suggest that S-PT84 attenuates diet-induced insulin resistance and subsequent NASH development by maintaining gut permeability. Thus, S-PT84 represents a feasible approach to prevent the development of NASH.
Gregory S Y Ong, Timothy J Cole, Gregory H Tesch, James Morgan, Jennifer K Dowling, Ashley Mansell, Peter J Fuller, and Morag J Young
MR activation in macrophages is critical for the development of cardiac inflammation and fibrosis. We previously showed that MR activation modifies macrophage pro-inflammatory signalling, changing the cardiac tissue response to injury via both direct gene transcription and JNK/AP-1 second messenger pathways. In contrast, MR-mediated renal electrolyte homeostasis is critically determined by DNA-binding-dependent processes. Hence, ascertaining the relative contribution of MR actions via DNA binding or alternative pathways on macrophage behaviour and cardiac inflammation may provide therapeutic opportunities which separate the cardioprotective effects of MR antagonists from their undesirable renal potassium-conserving effects. We developed new macrophage cell lines either lacking MR or harbouring a mutant MR incapable of DNA binding. Western blot analysis demonstrated that MR DNA binding is required for lipopolysaccharide (LPS), but not phorbol 12-myristate-13-acetate (PMA), induction of the MAPK/pJNK pathway in macrophages. Quantitative RTPCR for pro-inflammatory and pro-fibrotic targets revealed subsets of LPS- and PMA-induced genes that were either enhanced or repressed by the MR via actions that do not always require direct MR-DNA binding. Analysis of the MR target gene and profibrotic factor MMP12 identified promoter elements that are regulated by combined MR/MAPK/JNK signalling. Evaluation of cardiac tissue responses to an 8-day DOC/salt challenge in mice selectively lacking MR DNA-binding in macrophages demonstrated levels of inflammatory markers equivalent to WT, indicating non-DNA binding-dependent MR signalling in macrophages is sufficient for DOC/salt-induced tissue inflammation. Our data demonstrate that the MR regulates a macrophage pro-inflammatory phenotype and cardiac tissue inflammation, partially via pathways that do not require DNA binding.
Juliana I Candelaria, Maria B Rabaglino, and Anna C Denicol
Follicle-stimulating hormone (FSH) is required for ovarian antral folliculogenesis and steroidogenesis, and there is increasing evidence that it may play critical roles in preantral follicle development. We hypothesized that preantral follicles began responding to FSH as early as the primary stage of development. Our objectives were to establish whether the FSH receptor (FSHR) was expressed in bovine preantral follicles and to determine the effects of FSH in these follicles and the surrounding ovarian tissue. Preantral follicles were isolated from bovine ovaries and subjected to immunolocalization of FSHR. Ovarian cortical strips were cultured with FSH or vehicle for 2 or 4 days and subjected to RNA sequencing, hematoxylin/eosin staining and immunostaining for p42/44 MAPK. Finally, cortical strips were cultured for four days with FSH before western blot analysis of total and phosphorylated p42/44 MAPK, and total aromatase. We found greater FSHR labeling intensity per cell in preantral follicles at the primary stage compared to other stages (P < 0.05). FSH upregulated genes involved in energy metabolism and MAPK signaling and downregulated genes related to phagosome and allograft rejection in the ovarian cortex. Preantral follicles cultured in situ with FSH had greater expression of total p42/44 MAPK (P < 0.05), but no difference was detected in whole tissue western blot for phosphorylated p42/44 MAPK or aromatase. We conclude that the FSHR is expressed in preantral follicles as early as the primary stage of development, and that FSH upregulates cell metabolism and activates MAPK signaling pathways in preantral follicles.