Aldosterone is a mineralocorticoid hormone involved in controlling electrolyte balance, blood pressure, and cellular signaling. It plays a pivotal role in cardiovascular and metabolic physiology. Excess aldosterone activates mineralocorticoid receptors, leading to subsequent inflammatory responses, increased oxidative stress, and tissue remodeling. Various mechanisms have been reported to link aldosterone with cardiovascular and metabolic diseases. However, mitochondria, responsible for energy generation through oxidative phosphorylation, have received less attention regarding their potential role in aldosterone-related pathogenesis. Excess aldosterone leads to mitochondrial dysfunction, and this may play a role in the development of cardiovascular and metabolic diseases. Aldosterone has the potential to affect mitochondrial structure, function, and dynamic processes, such as mitochondrial fusion and fission. In addition, aldosterone has been associated with the suppression of mitochondrial DNA, mitochondria-specific proteins, and ATP production in the myocardium through mineralocorticoid receptor, nicotinamide adenine dinucleotide phosphate oxidase, and reactive oxygen species pathways. In this review, we explore the mechanisms underlying aldosterone-induced cardiovascular and metabolic mitochondrial dysfunction, including mineralocorticoid receptor activation and subsequent inflammatory responses, as well as increased oxidative stress. Furthermore, we review potential therapeutic targets aimed at restoring mitochondrial function in the context of aldosterone-associated pathologies. Understanding these mechanisms is vital, as it offers insights into novel therapeutic strategies to mitigate the impact of aldosterone-induced mitochondrial dysfunction, thereby potentially improving the outcomes of individuals affected by cardiovascular and metabolic disorders.

Ghrelin has effects that range from the maturation of the central nervous system to the regulation of energy balance. The production of ghrelin increases significantly during the first weeks of life. Studies have addressed the metabolic effects of liver-expressed antimicrobial peptide 2 (LEAP2) in inhibiting the effects evoked by ghrelin, mainly in glucose homeostasis, insulin resistance, and lipid metabolism. Despite the known roles of ghrelin in the postnatal development, little is known about the long-term metabolic influences of modulation with the endogenous expressed growth hormone secretagogue receptor (GHSR) inverse agonist LEAP2. This study aimed to evaluate the contribution of GHSR signalling during perinatal phases, to neurodevelopment and energy metabolism in young animals, under inverse antagonism by LEAP2_[1–14]. For this, two experimental models were used: (i) LEAP2_[1–14] injections in female rats during the pregnancy. (ii) Postnatal modulation of GHSR with LEAP2_[1–14] or MK677. Perinatal GHSR modulation by LEAP2_[1–14] impacts glucose homeostasis in a sex and phase-dependent manner, despite no effects on body weight gain or food intake. Interestingly, liver PEPCK expression was remarkably impacted by LEAP2 injections. The observed results suggests that perinatal LEAP2 exposure can modulate liver metabolism and systemic glucose homeostasis. In addition, these results, although not expressive, may just be the beginning of the metabolic imbalance that will occur in adulthood.

Glucose-dependent insulinotropic polypeptide (GIP) and glucagon-like-peptide-1 (GLP-1) are incretin hormones that stimulate insulin secretion and improve glycemic control in individuals with type 2 diabetes (T2D). Data from several cardiovascular outcome trials for GLP-1 receptor (GLP-1R) agonists have demonstrated significant reductions in the occurrence of major adverse cardiovascular events in individuals with T2D. Although the cardiovascular actions attributed to GLP-1R agonism have been extensively studied, little is known regarding the cardiovascular consequences attributed to GIP receptor (GIPR) agonism. As there is now an increasing focus on the development of incretin-based co-agonist therapies that activate both the GLP-1R and GIPR, it is imperative that we understand the mechanism(s) through which these incretins impact cardiovascular function. This is especially important considering that cardiovascular disease represents the leading cause of death in individuals with T2D. With increasing evidence that perturbations in cardiac energy metabolism are a major contributor to the pathology of diabetes-related cardiovascular disease, this may represent a key component through which GLP-1R and GIPR agonism influence cardiovascular outcomes. Not only do GIP and GLP-1 increase the secretion of insulin, they may also modify glucagon secretion, both of which have potent actions on cardiac substrate utilization. Herein we will discuss the potential direct and indirect actions through which GLP-1R and GIPR agonism impact cardiac energy metabolism while interrogating the evidence to support whether such actions may account for incretin-mediated cardioprotection in T2D.

The novel adipokine asprosin produced by the furin enzymatic cleavage of profibrillin 1 protein (encoded by the Fbn1 gene) is implicated in regulating many physiological functions including reproduction in mammals. In males, asprosin is reported to increase sperm density, sperm motility, and steroid production by interacting with Olfr734 belonging to the G-protein coupled receptor family (GPCR). In 2023, our group predicted and characterized asprosin in silico for the first time and demonstrated the robust expression of fbn1, and furin in the gonads of teleost spotted snakehead (ss) Channa punctata. Taking it forward, in the current study, we have investigated the effect of asprosin on the testicular functions of the spotted snakehead. As C. punctata is a seasonal breeder, reproductive-phase dependent expression of fbn1 in the testis was analysed, which showed significant upregulation during the preparatory and post-spawning phases. In addition, bacterially overexpressed recombinant asprosin of C. punctata was purified to study the effect of ss asprosin on gametogenesis and steroidogenesis. Ex vivo treatment with recombinant asprosin resulted in significant upregulation of spermatogenic marker genes pcna, aldh1a2, cyp26a1, and sycp3. Asprosin also enhanced the gene expression of gonadotropin receptors as well as sex steroid receptors in addition to steroidogenic genes, star and cyp17a1. Further to explore the downstream signalling cascade, the second messenger of GPCRs, cAMP level following asprosin treatment was analysed. Asprosin treatment prominently enhanced the cAMP levels, thereby indicating the involvement of GPCR in transduction of asprosin action. Hence, the study elucidates the regulation of male reproductive function by asprosin in spotted snakehead.

Osteosarcopenia, which refers to the concomitant presence of osteoporosis and sarcopenia, is expected to increase in the rapidly progressive aging world, with serious clinical implications. However, the pathophysiology of osteosarcopenia has not been fully elucidated, and no optimal treatment specific to osteosarcopenia is available. The RANKL–RANK pathway is widely used as a therapeutic target for osteoporosis. Growing evidence supports the importance of the RANKL–RANK pathway, not only in bone, but also in muscle, and the therapeutic potential of targeting this pathway in muscle diseases has been noted. The muscles and bones closely communicate with each other through various secretory factors called myokines and osteokines. This review covers the roles of the RANKL–RANK pathway in the bone and muscle and their reciprocal interactions. Moreover, we will suggest future directions to move forward for the treatment of osteosarcopenia to prepare for an upcoming aging society.

Biallelic variants of steroidogenic acute regulatory protein (STAR/STARD1) may cause primary adrenal insufficiency and 46,XY disorder of sex development. STAR plays a pivotal role in transporting cholesterol into mitochondria where cholesterol serves as an essential substrate for initiating steroid biosynthesis by its conversion to pregnenolone. Generally, loss-of-function mutations of STAR cause the classic form of lipoid congenital adrenal hyperplasia (LCAH) where steroidogenesis of the adrenal cortex and the gonads is severely affected. By contrast, partial activity of STAR causes a less severe phenotype, the non-classic LCAH, which is characterized by later onset and initial manifestation with isolated adrenal insufficiency only. Disease-causing STAR variants are very rare. Numerous variants of all types have been described worldwide. Prevailing variants have been reported from Japan and Korea and in some population clusters where STAR is more common. Genotype–phenotype correlation is pretty good for STAR variants. While the exact mechanisms of cholesterol transport into mitochondria for steroidogenesis are still under investigation, the important role of STAR in this process is evident by inactivating STAR variants causing LCAH. The mechanism of disease with STAR deficiency is best described by a two-hit model: the first hit relates to impaired cholesterol import into mitochondria and thus lack of substrate for all steroid hormone biosynthesis; the second hit then relates to massive cytoplasmic lipid overload (evidenced by typically enlarged and fatty adrenal glands) leading to cell death and organ destruction. This review summarizes phenotype and genotype characteristics of human STAR variants found through the ClinVar database.

Coffee is one of the three most consumed beverages in the world. It is made by first roasting coffee beans, and then grinding and boiling or steeping the roasted beans in water (brewing). The process of roasting and brewing produces a complex mix of bioactive compounds, including methylxanthines (caffeine, theobromine, theophylline), diterpenes, chlorogenic acid, trigonelline, flavonoids, and hydroxycinnamic acid. In the body, these compounds may be metabolized to produce other bioactive compounds. For example, caffeine is primarily (80%) broken down by demethylation to produce paraxanthine. In the post-ingestion period, levels of paraxanthine may be higher than caffeine due to its slower elimination. Hence, while paraxanthine is not found in coffee itself, it has many of the same properties as caffeine and may be a major contributor to its metabolic effects. The impacts of caffeine and paraxanthine on metabolism relate to their impact on adenosine receptors (notably the A2A receptor). It has been known for almost 100 years that intake of coffee stimulates metabolism by between 5% and 20% for at least 3 h. About half of the increase in metabolic rate after drinking coffee is due to caffeine and derivatives, but the source of the other half is unclear. There are large differences in the response to the same amount of coffee in different individuals, which may be related to caffeine clearance rates, effects of other unknown pathways, genetic polymorphism, age, sex, and body composition.

LEAP2, a liver-derived antagonist for the ghrelin receptor, GHSR1a, counteracts effects of ghrelin on appetite and energy balance. Less is known about its impact on blood glucose-regulating hormones from pancreatic islets. Here we investigate whether acyl-ghrelin (AG) and LEAP2 regulate islet hormone release in a cell type- and sex-specific manner. Hormone content from secretion experiments with isolated islets from male and female mice was measured by radioimmunoassay and mRNA expression by qPCR. LEAP2 enhanced insulin secretion in islets from males (p<0.01) but not females (p<0.2), whilst AG-stimulated somatostatin release was significantly reversed by LEAP2 in males (p<0.001) but not females (p<0.2). Glucagon release was not significantly affected by AG and LEAP2. Ghsr1a, Ghrelin, Leap2, Mrap2, Mboat4 and Sstr3 islet mRNA expression did not differ between sexes. In control male islets maintained without 17-beta oestradiol (E2), AG exerted an insulinostatic effect (p<0.05), with a trend towards reversal by LEAP2 (p=0.06). Both were abolished by 72h E2 pre-treatment (10 nmol/l, p<0.2). AG-stimulated somatostatin release was inhibited by LEAP2 from control (p<0.001) but not E2-treated islets (p<0.2). LEAP2 and AG did not modulate insulin secretion from MIN6 beta cells and Mrap2 was downregulated (P<0.05) and Ghsr1a upregulated (P<0.0001) in islets from Sst^-/- mice. Our findings show that AG and LEAP2 regulate insulin and somatostatin release in an opposing and sex-dependent manner, which in males can be modulated by E2. We suggest that regulation of SST release is a key starting point for understanding the role of GHSR1a in islet function and glucose metabolism.

Liraglutide, an analog of the incretin hormone, glucagon-like peptide 1 (GLP-1), is widely used for obesity and type 2 diabetes treatment. However, there is scarce information about its effects on testicular function. Within the testis, Sertoli cells (SCs) provide nutritional support for germ cells: they metabolize glucose to lactate, which is delivered to germ cells to be used as a preferred energy substrate. Besides, SCs use fatty acids (FAs) as an energy source and store them as triacylglycerols (TAGs) within lipid droplets (LDs), which serve as an important energy reserve. In the present study, twenty-day-old rat SC cultures were used to assess whether liraglutide affects their metabolic functions related to nutritional support and lipid storage. The results show that liraglutide does not modify glucose consumption or lactate production. However, it increases TAG levels and LD content. These effects are accompanied by an increase in the mRNA levels of the fatty acid transporter FAT/CD36, glycerol-3-phosphate-acyltransferases 3, and perilipins 1 and 4. Then, the participation of the cAMP/PKA signaling pathway was explored. We observed that H89 (PKA inhibitor) decreases LD upregulation elicited by liraglutide, and that dibutyryl cAMP increases LD content and the expression of related genes. In summary, liraglutide promotes lipid storage in SCs through the regulation of key regulatory genes involved in FA transport, TAG synthesis, and LD formation. Considering the importance of lipid storage in SC energetic homeostasis maintenance, we postulate that liraglutide might improve the overall energetic status of the seminiferous tubule.

Systemic glucocorticoid excess causes several adverse metabolic conditions, most notably Cushing’s syndrome. These effects are amplified by the intracellular enzyme 11β-hydroxysteroid dehydrogenase type 1 (11β-HSD1). Here we determined the less well characterised effects of glucocorticoid excess, and the contribution of 11β-HSD1 amplification, on metabolic rate in mice. Male and female C57BL/6J (wild type, WT) and 11β-HSD1 knock out (11β-HSD1KO) mice were treated with high-dose corticosterone or a vehicle control for 3 weeks. Indirect calorimetry was conducted during the final week of treatment, with or without fasting, to determine the impact on metabolic rate. We found that corticosterone treatment elevated metabolic rate and promoted carbohydrate utilisation primarily in female WT mice, with effects more pronounced during the light phase. Corticosterone treatment also resulted in greater fat accumulation in female WT mice. Corticosterone induced hyperphagia was identified as a likely causal factor altering the respiratory exchange ratio (RER) but not energy expenditure (EE). Male and female 11β-HSD1KO mice were protected against these effects. We identify novel metabolic consequences of sustained glucocorticoid excess, identify a key mechanism of hyperphagia and demonstrate that 11β-HSD1 is required to manifest the full metabolic derangement.