Molecular and Cellular Endocrinology最新文献

Thyroid hormone receptor α1 (TRα1) undergoes nucleocytoplasmic shuttling and mediates gene expression in response to thyroid hormone (T3). In Resistance to Thyroid Hormone Syndrome α (RTHα), certain TRα1 mutants have higher affinity for nuclear corepressor 1 (NCoR1) and may form stable complexes that are not released in the presence of T3. Here, we examined whether NCoR1 modulates intranuclear mobility and nuclear retention of TRα1 or RTHα-associated mutants in transfected human cells, as a way of analyzing critical structural components of TRα1 and to further explore the correlation between mutations in TRα1 and aberrant intracellular trafficking. We found no significant difference in intranuclear mobility, as measured by fluorescence recovery after photobleaching, between TRα1 and select RTHα mutants, irrespective of NCoR1 expression. Nuclear-to-cytoplasmic fluorescence ratios of RTHα mutants, however, varied from TRα1 when NCoR1 was overexpressed, with a significant increase in nuclear retention for A263V and a significant decrease for A263S and R384H. In NCoR1-knockout cells, nuclear retention of A263S, A263V, P389R, A382P, C392X, and F397fs406X was significantly decreased compared to control (wild-type) cells. Luciferase reporter gene transcription mediated by TRα1 was significantly repressed by both NCoR1 overexpression and NCoR1 knockout. Most RTHα mutants showed minimal induction regardless of NCoR1 levels, but T3-mediated transcriptional activity was decreased for R384C and F397fs406X when NCoR1 was overexpressed, and also decreased for N359Y in NCoR1-knockout cells. Our results suggest a complex interaction between NCoR1 and RTHα mutants characterized by aberrant intracellular localization patterns and transcriptional activity that potentially arise from variable repressor complex stability, and may provide insight into RTHα pathogenesis on a molecular and cellular level.

OXER1, the receptor for the arachidonic acid metabolite 5-οxo-eicosatetraenoic acid (5-oxo-ETE), has been reported to also bind and mediate the membrane-initiated actions of androgens. Indeed, androgens antagonize the 5-oxo-ETE effects through OXER1, affecting a number of signaling pathways and inhibiting cancer cell proliferation and migration. OXER1, being a GPCR, was classically described to be localized in the plasma membrane. However, for numerous GPCRs, there is now strong evidence that they can be also found in other cellular compartments, including the nucleus. The aim of the present work was to investigate OXER1's possible localization in the nucleus and identify the mechanism(s) involved. For this purpose, we verified OXER1's nuclear presence by immunofluorescence and western blot, in whole cells and nuclei of two different prostate cancer cell lines (DU-145 and LNCaP) and in CHO cells transfected with a GFP labelled OXER1, both in untreated and OXER1 ligands' treated cells. Mutated, OXER1-tGFP expressing, CHO cells were used to verify that OXER1 agonist (5-oxo-ETE) binding is necessary for OXER1 nuclear translocation. NLS sequences were in silico identified, and a specific inhibitor, as well as, specific importins' siRNAs were also utilized to explore the mechanism involved. Moreover, we examined the role of palmitoylation in OXER1 nuclear translocation by in silico identifying possible palmitoylation sites and using a palmitoylation inhibitor. Our results clearly show that OXER1 can be localized in the nucleus, in an agonist-dependent manner, that is inhibited by androgens. We also provide evidence for two possible mechanisms for its nuclear trafficking, that involve receptor palmitoylation and importin-mediated cytoplasmic-nuclear transport. In our knowledge, it is the first time that a membrane androgen receptor is identified into the nucleus, suggesting an alternative, more direct, mode of action, involving nuclear mechanisms. Therefore, our findings provide new insights on androgen-mediated actions and androgen-lipid interactions, and reveal new possible therapeutic targets, not only for cancer, but also for other pathological conditions in which OXER1 may have an important role.

Beyond their link to metabolic issues like type 2 diabetes, factors like lifestyle, environment, and excess weight may also influence fertility. Fibroblast growth factor 21 (FGF21), a liver-derived hormone linked to energy balance, has recently emerged as a potential player in female mammalian reproduction. In male, only two studies have described potential effects of FGF21 on fertility. A recent study has described a negative correlation observed in obese patients presenting a low testosterone level associated with elevated FGF21 plasma levels. To investigate the role of FGF21 in steroidogenesis, we have studied the involvement of FGF21 in lipid and steroid activity by Leydig cells.

Leydig cell model expressed all FGF21 receptors and β-Klotho cofactor as determined by RT-qPCR and by western-blot. Cultured mLTC-1 Leydig cell line exposed to increasing FGF21 concentration induced phosphorylation (Ser 473) of Akt and modified the CREB factor activity, suggesting the functionality of the FGF21 pathway.

FGF21 consequences on mLTC-1 Leydig cells are inhibition of the lipid synthesis, leading to a reduction in the content of lipid droplets. The drop in lipid synthesis is associated with a reduction in the amount of lipids (mainly PUFA, cholesterol esterified, and triglycerides) as measured by lipidomic approach. The main consequence is to reduce the quantity of cholesterol, the steroid precursor, in mLTC-1 Leydig cells and is associated with a low production in testosterone. The decrease in androgens was also associated with a reduction in the steroid enzyme genes expression, which are under the control of CREB activity, and present a lower activity due to low cAMP intracellular levels.

In vivo, steroid production was lowering after FGF21 administration in adult male mice associated to a decrease in progressive motility and velocity of sperm. In addition, these experimental data are reinforced by a data mining analysis focused on “gonad“ terms in 1,319,905 article references showing the link already described between FGF21 with the fatty acids pathways, cholesterol storage, and steroid production.

In conclusion, we demonstrated that Leydig cells in the testes present a functional FGF21 pathway, which regulates lipid metabolism and steroid function. In mLTC-1 Leydig cells, FGF21 reduced cholesterol, PUFA content, and testosterone production. Finally, this work highlighted that the hepatokine FGF21 could have a negative impact on androgen synthesis and testicular activity.

The vitamin D receptor (VDR) is associated with antioxidative and anti-inflammatory effects and modulation of the renin-angiotensin-aldosterone system. This study evaluated whether VDR agonist paricalcitol protects renal ischemia-reperfusion (IR) induced tubular injury in rats by evaluating: 1) ATP-dependent tubular Na⁺ transport; 2) renal redox signaling; 3) renal content of proinflammatory cytokines TNF-α and IL-6; and 4) renal content of renin and angiotensin II receptor type 1 (AT₁R). Paricalcitol prevented IR-induced tubular injury, evidenced by the prevention of histopathological changes and renal fibrosis with preservation of the activity of ATP-dependent Na⁺ transporters in the renal cortex. Paricalcitol decreased renal oxidative stress by reducing NADPH oxidase activity and increasing catalase. Paricalcitol also decreased the renal content of TNF-α, IL-6, and AT₁R. The NADPH oxidase inhibitor apocynin did not present additive protection to paricalcitol-induced effects. The protective effects of paricalcitol on tubular injury induced by renal IR may dependent on the modulation of redox and proinflammatory signaling and renal angiotensin II/AT₁R signaling.

Pheochromocytomas and paragangliomas (PPGL) are rare neuroendocrine tumors derived from chromaffin cells in the autonomic nervous system. Depending on their location, these tumors are capable of excessive catecholamine production, which may lead to uncontrolled hypertension and other life-threatening complications. They are associated with a significant risk of metastatic disease and are often caused by an inherited germline mutation.

Although surgery can cure localized disease and lead to remission, treatments for metastatic PPGL (mPPGL)—including chemotherapy, radiopharmaceutical agents, multikinase inhibitors, and immunotherapy used alone or in combination— aim to control tumor growth and limit organ damage.

Substantial advances have been made in understanding hereditary and somatic molecular signaling pathways that play a role in tumor growth and metastasis. Treatment options for metastatic disease are rapidly evolving, and this paper aims to provide a brief overview of the management of mPPGL with a focus on therapy options.

The developmental origins of healthy and disease (DOHaD) concept has demonstrated a higher rate of chronic diseases in the adult population of individuals whose mothers experienced severe maternal protein restriction (MPR). Using proteomic and in silico analyses, we investigated the lung proteomic profile of young and aged rats exposed to MPR during pregnancy and lactation. Our results demonstrated that MPR lead to structural and immune system pathways changes, and this outcome is coupled with a rise in the PI3k-AKT-mTOR signaling pathway, with increased MMP-2 activity, and CD8 expression in the early life, with long-term effects with aging. This led to the identification of commonly or inversely differentially expressed targets in early life and aging, revealing dysregulated pathways related to the immune system, stress, muscle contraction, tight junctions, and hemostasis. We identified three miRNAs (miR-378a-3p, miR-378a-5p, let-7a-5p) that regulate four proteins (ACTN4, PPIA, HSPA5, CALM1) as probable epigenetic lung marks generated by MPR. In conclusion, MPR impacts the lungs early in life, increasing the possibility of long-lasting negative outcomes for respiratory disorders in the offspring.

Progesterone (P4) is predicted to act as a negative regulatory hormone for oocyte maturation events; however, its local effects during follicular development remain poorly understood in bovine. The complex process of oocyte meiosis progression is dependent on cellular communication among follicular cells. Besides, the breakdown of this communication, mainly between cumulus cells (CC) and oocyte, through the retraction of cumulus projections connecting these cells can impact oocyte maturation. In our study, we observed that follicles from the ovary ipsilateral to the corpus luteum (CL) containing high intrafollicular P4 concentrations enhance the abundance of proteins detected in follicular-derived small extracellular vesicles (sEVs) predicted to be involved in the retraction of membrane projections based on actin filaments, such as transzonal projections (TZPs). Conversely, we found that follicles from the ovary contralateral to the CL, which contained low intrafollicular P4 concentrations, had a high detection of proteins predicted to regulate the maintenance of TZPs. We also performed RNAseq analysis which demonstrated that 177 genes were differentially expressed in CC under the different P4 environments. Bioinformatic analysis points to changes associated to cell metabolism in cells from follicles ipsilateral to the CL in comparison to genes involved in cell communication in CC from follicles contralateral to the CL. Our functional analysis experiment confirmed that supplementation of cumulus-oocyte complexes during in vitro maturation with P4 at concentration similar to ipsilateral follicles reduces the number of TZPs. In summary, our study underscores a direct association between P4 concentration and cumulus-oocyte interaction, with potential consequences for the acquisition of oocyte competence.

Mitochondrial dysfunction and metabolic disorder have been associated to age-related subfertility, however, the precise molecular mechanism controlling the development of fertile oocytes in aging females remains elusive. Leptin plays an important role in the maintenance of energy homeostasis, as both excessive or insufficient levels can affect the body weight and fertility of mice. Here, we report that leptin A deficiency affects growth and shortens reproductive lifespan by reducing fertility in medaka (Oryzias latipes). Targeted disruption of lepa (lepa^−/−) females reduced their egg laying and fertility compared to normal 3-month-old females (lepa^+/+ sexual maturity), with symptoms worsening progressively at the age of 6 months and beyond. Transcriptomic analysis showed that differentially expressed genes involved in metabolic and mitochondrial pathways were significantly altered in lepa^−/− ovaries compared with the normal ovaries at over 6 months old. The expression levels of the autophagy-promoting genes ulk1a, atg7 and atg12 were significantly differentiated between normal and lepa^−/− ovaries, which were further confirmed by quantitative polymerase chain reaction analysis, indicating abnormal autophagy activation and mitochondrial dysfunction in oocyte development lacking lepa. Transmission electron microscopy observations further confirmed these mitochondrial disorders in lepa-deficient oocytes. In summary, these research findings provide novel insights into how leptin influences female fertility through mitochondrial-mediated oocyte development.

Insulin, a critical hormone in the human body, exerts its effects by binding to insulin receptors and regulating various cellular processes. While nitric oxide (NO) plays an important role in insulin secretion and acts as a mediator in the signal transduction pathway between upstream molecules and downstream effectors, holds a significant position in the downstream signal network of insulin. Researches have shown that the insulin-NO system exhibits a dual regulatory effect within the central nervous system, which is crucial in the regulation of diabetic encephalopathy (DE). Understanding this system holds immense practical importance in comprehending the targets of existing drugs and the development of potential therapeutic interventions. This review extensively examines the characterization of insulin, NO, Nitric oxide synthase (NOS), specific NO pathway, their interconnections, and the mechanisms underlying their regulatory effects in DE, providing a reference for new therapeutic targets of DE.