Adipocyte Glucocorticoid Receptor Deficiency Promotes Adipose Tissue Expandability and Improves the Metabolic Profile Under Corticosterone Exposure

Sphingosine kinase 1 is induced by glucocorticoids in adipose derived stem cells and enhances glucocorticoid mediated signaling in adipose expansion

Sphingosine kinase 1 (SphK1) plays a crucial role in regulating metabolic pathways within adipocytes and is elevated in the adipose tissue of obese mice. While previous studies have reported both pro- and inhibitory effects of SphK1 and its product, sphingosine-1-phosphate (S1P), on adipogenesis, the precise mechanisms remain unclear. This study explores the timing and downstream effects of SphK1/S1P expression and activation during in vitro adipogenesis. We demonstrate that the synthetic glucocorticoid dexamethasone robustly induces SphK1 expression, suggesting its involvement in glucocorticoid-dependent signaling during adipogenesis. Notably, the activation of C/EBPδ, a key gene in early adipogenesis and a target of glucocorticoids, is diminished in SphK1-/- adipose-derived stem cells (ADSCs). Furthermore, glucocorticoid administration promotes adipose tissue expansion via SphK1 in a depot-specific manner. Although adipose expansion still occurs in SphK1-/- mice, it is significantly reduced. These findings indicate that while SphK1 is not essential for adipogenesis, it enhances early gene activation, thereby facilitating adipose tissue expansion.

MicroRNA Profile of Mouse Adipocyte-Derived Extracellular Vesicles

The post-transcriptional control of gene expression is a complex and evolving field in adipocyte biology, with the premise that the delivery of microRNA (miRNA) species to the obese adipose tissue may facilitate weight loss. Cells shed extracellular vesicles (EVs) that may deliver miRNAs as intercellular messengers. However, we know little about the miRNA profile of EVs secreted by adipocytes during postnatal development. Here, we defined the miRNA cargo of EVs secreted by mouse adipocytes in two distinct phases of development: on postnatal day 6, when adipocytes are lipolytic and thermogenic, and on postnatal day 56, when adipocytes have active lipogenesis. EVs were collected from cell culture supernatants, and their miRNA profile was defined by small RNA sequencing. The most abundant miRNA of mouse adipocyte-derived EVs was mmu-miR-148a-3p. Adipocyte EVs on postnatal day 6 were hallmarked with mmu-miR-98-5p, and some miRNAs were specific to this developmental stage, such as mmu-miR-466i-5p and 12 novel miRNAs. Adipocytes on postnatal day 56 secreted mmu-miR-365-3p, and 16 miRNAs were specific to this developmental stage. The miRNA cargo of adipocyte EVs targeted gene networks of cell proliferation, insulin signaling, interferon response, thermogenesis, and lipogenesis. We provided here a database of miRNAs secreted by developing mouse adipocytes, which may be a tool for further studies on the regulation of gene networks that control mouse adipocyte development.

Effects of glucocorticoids on adipose tissue plasticity

Glucocorticoids (GCs) play an important role in metabolic adaptation, regulating carbohydrate-lipid homeostasis and the immune system. Because they also have anti-inflammatory and immunosuppressive properties, synthetic analogues of GCs have been developed and are widely used in the treatment of chronic inflammatory conditions and in organ transplantation. GCs are among the most commonly prescribed drugs in the world. However, long term and high GC doses can cause side effects such as GC-induced diabetes and lipodystrophy. In recent years, a large number of independent studies have reported the effects of constitutive and adipocyte-specific deletion of the GC receptor (GR) in mice under different diets and treatments, resulting in contrasting phenotypes. To avoid potential compensatory mechanisms associated with the constitutive adipocyte GR silencing during adipose tissue development, our team has generated an inducible mouse model of GR deletion specifically in the adipocyte (AdipoGR-KO). Using this mouse model, we were able to demonstrate the critical role of the adipocyte GR in GC-induced metabolic changes. Indeed, under conditions of hypercorticism, AdipoGR-KO mice showed an improvement in glucose tolerance and insulin sensitivity, as well as in lipid profile, despite a massive increase in adiposity. This result is explained by a densification of adipose tissue vascularization, highlighting the repressive role of adipocyte GR in the healthy expansion of this tissue. Our work has largely contributed to the demonstration of the important role of the adipocyte GR in the physiology and pathophysiology of the adipose tissue and its impact on energy homeostasis.

Adipose tissue in cortisol excess: What Cushing's syndrome can teach us?

Endogenous Cushing's syndrome (CS) is a rare condition due to prolonged exposure to elevated circulating cortisol levels that features its typical phenotype characterised by moon face, proximal myopathy, easy bruising, hirsutism in females and a centripetal distribution of body fat. Given the direct and indirect effects of hypercortisolism, CS is a severe disease burdened by increased cardio-metabolic morbidity and mortality in which visceral adiposity plays a leading role. Although not commonly found in clinical setting, endogenous CS is definitely underestimated leading to delayed diagnosis with consequent increased rate of complications and reduced likelihood of their reversal after disease control. Most of all, CS is a unique model for systemic impairment induced by exogenous glucocorticoid therapy that is commonly prescribed for a number of chronic conditions in a relevant proportion of the worldwide population. In this review we aim to summarise on one side, the mechanisms behind visceral adiposity and lipid metabolism impairment in CS during active disease and after remission and on the other explore the potential role of cortisol in promoting adipose tissue accumulation.

Inflammatory liver diseases and susceptibility to sepsis

Patients with inflammatory liver diseases, particularly alcohol-associated liver disease and metabolic dysfunction-associated fatty liver disease (MAFLD), have higher incidence of infections and mortality rate due to sepsis. The current focus in the development of drugs for MAFLD is the resolution of non-alcoholic steatohepatitis and prevention of progression to cirrhosis. In patients with cirrhosis or alcoholic hepatitis, sepsis is a major cause of death. As the metabolic center and a key immune tissue, liver is the guardian, modifier, and target of sepsis. Septic patients with liver dysfunction have the highest mortality rate compared with other organ dysfunctions. In addition to maintaining metabolic homeostasis, the liver produces and secretes hepatokines and acute phase proteins (APPs) essential in tissue protection, immunomodulation, and coagulation. Inflammatory liver diseases cause profound metabolic disorder and impairment of energy metabolism, liver regeneration, and production/secretion of APPs and hepatokines. Herein, the author reviews the roles of (1) disorders in the metabolism of glucose, fatty acids, ketone bodies, and amino acids as well as the clearance of ammonia and lactate in the pathogenesis of inflammatory liver diseases and sepsis; (2) cytokines/chemokines in inflammatory liver diseases and sepsis; (3) APPs and hepatokines in the protection against tissue injury and infections; and (4) major nuclear receptors/signaling pathways underlying the metabolic disorders and tissue injuries as well as the major drug targets for inflammatory liver diseases and sepsis. Approaches that focus on the liver dysfunction and regeneration will not only treat inflammatory liver diseases but also prevent the development of severe infections and sepsis.

Glucocorticoids increase adiposity by stimulating Krüppel-like factor 9 expression in macrophages

The mechanisms underlying glucocorticoid (GC)-induced obesity are poorly understood. Macrophages are the primary targets by which GCs exert pharmacological effects and perform critical functions in adipose tissue homeostasis. Here, we show that macrophages are essential for GC-induced obesity. Dexamethasone (Dex) strongly induced Krüppel-like factor 9 (Klf9) expression in macrophages. Similar to Dex, lentivirus-mediated Klf9 overexpression inhibits M1 and M2a markers expression, causing macrophage deactivation. Furthermore, the myeloid-specific Klf9 transgene promotes obesity. Conversely, myeloid-specific Klf9-knockout (mKlf9KO) mice are lean. Moreover, myeloid Klf9 knockout largely blocks obesity induced by chronic GC treatment. Mechanistically, GC-inducible KLF9 recruits the SIN3A/HDAC complex to the promoter regions of Il6, Ptgs2, Il10, Arg1, and Chil3 to inhibit their expression, subsequently reducing thermogenesis and increasing lipid accumulation by inhibiting STAT3 signaling in adipocytes. Thus, KLF9 in macrophages integrates the beneficial anti-inflammatory and adverse metabolic effects of GCs and represents a potential target for therapeutic interventions.

Adipocyte Glucocorticoid Receptor Activation With High Glucocorticoid Doses Impairs Healthy Adipose Tissue Expansion by Repressing Angiogenesis

In humans, glucocorticoids (GCs) are commonly prescribed because of their anti-inflammatory and immunosuppressive properties. However, high doses of GCs often lead to side effects, including diabetes and lipodystrophy. We recently reported that adipocyte glucocorticoid receptor (GR)-deficient (AdipoGR-KO) mice under corticosterone (CORT) treatment exhibited a massive adipose tissue (AT) expansion associated with a paradoxical improvement of metabolic health compared with control mice. However, whether GR may control adipose development remains unclear. Here, we show a specific induction of hypoxia-inducible factor 1α (HIF-1α) and proangiogenic vascular endothelial growth factor A (VEGFA) expression in GR-deficient adipocytes of AdipoGR-KO mice compared with control mice, together with an increased adipose vascular network, as assessed by three-dimensional imaging. GR activation reduced HIF-1α recruitment to the Vegfa promoter resulting from Hif-1α downregulation at the transcriptional and posttranslational levels. Importantly, in CORT-treated AdipoGR-KO mice, the blockade of VEGFA by a soluble decoy receptor prevented AT expansion and the healthy metabolic phenotype. Finally, in subcutaneous AT from patients with Cushing syndrome, higher VEGFA expression was associated with a better metabolic profile. Collectively, these results highlight that adipocyte GR negatively controls AT expansion and metabolic health through the downregulation of the major angiogenic effector VEGFA and inhibition of vascular network development.

ARTICLE HIGHLIGHTS

Analysis of the management and therapeutic performance of diabetes mellitus employing special target

Diabetes mellitus (DM) is a chronic metabolic condition characterized predominantly by hyperglycemia. The most common causes contributing to the pathophysiology of diabetes are insufficient insulin secretion, resistance to insulin's tissue-acting effects, or a combination of both. Over the last 30 years, the global prevalence of diabetes increased from 4% to 6.4%. If no better treatment or cure is found, this amount might climb to 430 million in the coming years. The major factors of the disease's deterioration include age, obesity, and a sedentary lifestyle. Finding new therapies to manage diabetes safely and effectively without jeopardizing patient compliance has always been essential. Among the medications available to manage DM on this journey are glucagon-like peptide-1 agonists, thiazolidinediones, sulphonyl urease, glinides, biguanides, and insulin-targeting receptors discovered more than 10 years ago. Despite the extensive preliminary studies, a few clinical observations suggest this process is still in its early stages. The present review focuses on targets that contribute to insulin regulation and may be employed as targets in treating diabetes since they may be more efficient and secure than current and traditional treatments.

Treating the Side Effects of Exogenous Glucocorticoids; Can We Separate the Good From the Bad?

It is estimated that 2% to 3% of the population are currently prescribed systemic or topical glucocorticoid treatment. The potent anti-inflammatory action of glucocorticoids to deliver therapeutic benefit is not in doubt. However, the side effects associated with their use, including central weight gain, hypertension, insulin resistance, type 2 diabetes (T2D), and osteoporosis, often collectively termed iatrogenic Cushing's syndrome, are associated with a significant health and economic burden. The precise cellular mechanisms underpinning the differential action of glucocorticoids to drive the desirable and undesirable effects are still not completely understood. Faced with the unmet clinical need to limit glucocorticoid-induced adverse effects alongside ensuring the preservation of anti-inflammatory actions, several strategies have been pursued. The coprescription of existing licensed drugs to treat incident adverse effects can be effective, but data examining the prevention of adverse effects are limited. Novel selective glucocorticoid receptor agonists and selective glucocorticoid receptor modulators have been designed that aim to specifically and selectively activate anti-inflammatory responses based upon their interaction with the glucocorticoid receptor. Several of these compounds are currently in clinical trials to evaluate their efficacy. More recently, strategies exploiting tissue-specific glucocorticoid metabolism through the isoforms of 11β-hydroxysteroid dehydrogenase has shown early potential, although data from clinical trials are limited. The aim of any treatment is to maximize benefit while minimizing risk, and within this review we define the adverse effect profile associated with glucocorticoid use and evaluate current and developing strategies that aim to limit side effects but preserve desirable therapeutic efficacy.

Adipocyte STAT5 (signal transducer and activator of transcription 5) is not required for glucocorticoid-induced metabolic dysfunction

Excess glucocorticoid (GC) signaling in adipose tissue is a key driver of insulin resistance and hepatic steatosis, but underlying mechanisms have not been fully elucidated. Signal transducer and activator of transcription 5 (STAT5) signaling in adipocytes has also been implicated in the progression of similar metabolic disturbances. Although STAT5 has been shown to interact with the glucocorticoid receptor (GR) in many cell types including adipocytes, the relevance of the STAT5/GR complex has not been investigated in adipocytes. Adult male and female adipocyte-specific STAT5 knockout (STAT5AKO) and floxed mice were given corticosterone (CORT) or vehicle in their drinking water for 1 wk and examined for differences in their metabolic responses to GC excess. CORT-induced lipolysis, insulin resistance, and changes in body composition were comparable between genotypes and in both sexes. Adipocyte STAT5 is not necessary for GC-mediated progression of metabolic disease.NEW & NOTEWORTHY Both STAT5 and glucocorticoid receptor contribute to metabolic processes and type 2 diabetes, in large part, due to their functions in adipocytes. These two transcription factors can form a complex and function together. Our novel studies determined the role of adipocyte STAT5 in glucocorticoid-induced diabetes. We observed that STAT5 in adipocytes is not needed for glucocorticoid-induced diabetes.

Adipocyte Glucocorticoid Receptor Inhibits Immune Regulatory Genes to Maintain Immune Cell Homeostasis in Adipose Tissue

Glucocorticoids acting via the glucocorticoid receptors (GR) are key regulators of metabolism and the stress response. However, uncontrolled or excessive GR signaling adversely affects adipose tissue, including endocrine, immune, and metabolic functions. Inflammation of the adipose tissue promotes systemic metabolic dysfunction; however, the molecular mechanisms underlying the role of adipocyte GR in regulating genes associated with adipose tissue inflammation are poorly understood. We performed in vivo studies using adipocyte-specific GR knockout mice in conjunction with in vitro studies to understand the contribution of adipocyte GR in regulating adipose tissue immune homeostasis. Our findings show that adipocyte-specific GR signaling regulates adipokines at both mRNA and plasma levels and immune regulatory (Coch, Pdcd1, Cemip, and Cxcr2) mRNA gene expression, which affects myeloid immune cell presence in white adipose tissue. We found that, in adipocytes, GR directly influences Cxcr2. This chemokine receptor promotes immune cell migration, indirectly affecting Pdcd1 and Cemip gene expression in nonadipocyte or stromal cells. Our findings suggest that GR adipocyte signaling suppresses inflammatory signals, maintaining immune homeostasis. We also found that GR signaling in adipose tissue in response to stress is sexually dimorphic. Understanding the molecular relationship between GR signaling and adipose tissue inflammation could help develop potential targets to improve local and systemic inflammation, insulin sensitivity, and metabolic health.

Acute Deletion of the Glucocorticoid Receptor in Hepatocytes Disrupts Postprandial Lipid Metabolism in Male Mice

Hepatic lipid metabolism is highly dynamic, and disruption of several circadian transcriptional regulators results in hepatic steatosis. This includes genetic disruption of the glucocorticoid receptor (GR) as the liver develops. To address the functional role of GR in the adult liver, we used an acute hepatocyte-specific GR knockout model to study temporal hepatic lipid metabolism governed by GR at several preprandial and postprandial circadian timepoints. Lipidomics analysis revealed significant temporal lipid metabolism, where GR disruption results in impaired regulation of specific triglycerides, nonesterified fatty acids, and sphingolipids. This correlates with increased number and size of lipid droplets and mildly reduced mitochondrial respiration, most noticeably in the postprandial phase. Proteomics and transcriptomics analyses suggest that dysregulated lipid metabolism originates from pronounced induced expression of enzymes involved in fatty acid synthesis, β-oxidation, and sphingolipid metabolism. Integration of GR cistromic data suggests that induced gene expression is a result of regulatory actions secondary to direct GR effects on gene transcription.

Role of Adipose Tissue microRNAs in the Onset of Metabolic Diseases and Implications in the Context of the DOHaD

The worldwide epidemic of obesity is associated with numerous comorbid conditions, including metabolic diseases such as insulin resistance and diabetes, in particular. The situation is likely to worsen, as the increase in obesity rates among children will probably lead to an earlier onset and more severe course for metabolic diseases. The origin of this earlier development of obesity may lie in both behavior (changes in nutrition, physical activity, etc.) and in children's history, as it appears to be at least partly programmed by the fetal/neonatal environment. The concept of the developmental origin of health and diseases (DOHaD), involving both organogenesis and epigenetic mechanisms, encompasses such programming. Epigenetic mechanisms include the action of microRNAs, which seem to play an important role in adipocyte functions. Interestingly, microRNAs seem to play a particular role in propagating local insulin resistance to other key organs, thereby inducing global insulin resistance and type 2 diabetes. This propagation involves the active secretion of exosomes containing microRNAs by adipocytes and adipose tissue-resident macrophages, as well as long-distance communication targeting the muscles and liver, for example. Circulating microRNAs may also be useful as biomarkers for the identification of populations at risk of subsequently developing obesity and metabolic diseases.

Cortisol and cardiometabolic disease: a target for advancing health equity

Stress, in both intrinsic psychosocial and extrinsic physical environmental forms, can impact the development of, and outcomes in, cardiovascular disease (CVD) through allostatic load. Cortisol is a core hormonal mediator of allostatic load produced in response to various stresses. Alterations in morning serum cortisol and daily diurnal cortisol have been associated with adiposity, dyslipidemia, incident diabetes, and CVDs such as hypertension. The review examines the role of cortisol as a key mechanistic link between stress physiology and cardiometabolic disease. Importantly, we discuss the role of targeting cortisol through pharmacological, behavioral, and environmental interventions to advance health equity in cardiometabolic disease.

Animal Models of Cushing's Syndrome

Endogenous Cushing's syndrome is characterized by unique clinical features and comorbidities, and progress in the analysis of its genetic pathogenesis has been achieved. Moreover, prescribed glucocorticoids are also associated with exogenous Cushing's syndrome. Several animal models have been established to explore the pathophysiology and develop treatments for Cushing's syndrome. Here, we review recent studies reporting animal models of Cushing's syndrome with different features and complications induced by glucocorticoid excess. Exogenous corticosterone (CORT) administration in drinking water is widely utilized, and we found that CORT pellet implantation in mice successfully leads to a Cushing's phenotype. Corticotropin-releasing hormone overexpression mice and adrenal-specific Prkar1a-deficient mice have been developed, and AtT20 transplantation methods have been designed to examine the medical treatments for adrenocorticotropic hormone-producing pituitary neuroendocrine tumors. We also review recent advances in the molecular pathogenesis of glucocorticoid-induced complications using animal models.

FX5, a non-steroidal glucocorticoid receptor antagonist, ameliorates diabetic cognitive impairment in mice

Diabetic cognitive impairment (DCI) is a common diabetic complication characterized by learning and memory deficits. In diabetic patients, hyperactivated hypothalamic-pituitary-adrenal (HPA) axis leads to abnormal increase of glucocorticoids (GCs), which causes the damage of hippocampal neurons and cognitive impairment. In this study we investigated the cognition-improving effects of a non-steroidal glucocorticoid receptor (GR) antagonist 5-chloro-N-[4-chloro-3-(trifluoromethyl) phenyl]thiophene-2-sulfonamide (FX5) in diabetic mice. Four weeks after T1DM or T2DM was induced, the mice were administered FX5 (20, 40 mg·kg-1·d-1, i.g.) for 8 weeks. Cognitive impairment was assessed in open field test, novel object recognition test, Y-maze test, and Morris water maze test. We showed that FX5 administration significantly ameliorated the cognitive impairments in both type 1 and 2 diabetic mice. Similar cognitive improvement was observed in diabetic mice following brain GR-specific knockdown by injecting AAV-si-GR. Moreover, AAV-si-GR injection occluded the cognition-improving effects of FX5, suggesting that FX5 functioning as a non-steroidal GR antagonist. In PA-treated primary neurons (as DCI model in vitro), we demonstrated that FX5 (2, 5, 10 μM) dose-dependently ameliorated synaptic impairment via upregulating GR/BDNF/TrkB/CREB pathway, protected against neuronal apoptosis through repressing GR/PI3K/AKT/GSK3β-mediated tauopathy and subsequent endoplasmic reticulum stress. In LPS-treated primary microglia, FX5 dose-dependently inhibited inflammation through GR/NF-κB/NLRP3/ASC/Caspase-1 pathway. These beneficial effects were also observed in the hippocampus of diabetic mice following FX5 administration. Collectively, we have elucidated the mechanisms underlying the beneficial effects of non-steroidal GR antagonist FX5 on DCI and highlighted the potential of FX5 in the treatment of the disease.

Effects of ACTH-Induced Long-Term Hypercortisolism on the Transcriptome of Canine Visceral Adipose Tissue

Cushing’s syndrome, or hypercortisolism (HC), a common endocrinopathy in adult dogs, is caused by chronic hypercortisolemia. Among different metabolic disorders, this syndrome is associated with enhanced subcutaneous lipolysis and visceral adiposity. However, effects of HC in adipose tissue, especially regarding visceral adipose tissue (VAT), are still poorly understood. Herein, the transcriptomic effects of chronic HC on VAT of dogs were evaluated. For this, subcutaneously implanted ACTH-releasing pumps were used, followed by deep RNA sequencing of the canine VAT. Prolonged HC seems to affect a plethora of regulatory mechanisms in VAT of treated dogs, with 1190 differentially expressed genes (DEGs, p and FDR < 0.01) being found. The 691 downregulated DEGs were mostly associated with functional terms like cell adhesion and migration, intracellular signaling, immune response, extracellular matrix and angiogenesis. Treatment also appeared to modulate local glucocorticoid and insulin signaling and hormonal sensitivity, and several factors, e.g., TIMP4, FGF1, CCR2, CXCR4 and HSD11B1/2, were identified as possible important players in the glucocorticoid-related expansion of VAT. Modulation of their function during chronic HC might present interesting targets for further clinical studies. Similarities in the effects of chronic HC on VAT of dogs and humans are highlighted.

When therapeutic drugs lead to diabetes

Drug-induced diabetes mellitus is a growing problem in clinical practice. New, potent medications contribute to this problem in a population already at high risk of developing glucose disturbances because of poor lifestyle habits and high prevalence of being overweight/obese. The present review focuses on four important pharmacological classes: glucocorticoids; antipsychotics, especially second generation; antiretroviral therapies, which revolutionised the management of individuals with HIV; and immune checkpoint inhibitors, recently used for the immunotherapy of cancer. For each class, the prevalence of drug-induced diabetes will be evaluated, the most common clinical presentations will be described, the underlying mechanisms leading to hyperglycaemia will be briefly analysed, and some recommendations for appropriate monitoring and management will be proposed.

Efficacy of Azithromycin plus Glucocorticoid Adjuvant Therapy on Serum Inflammatory Factor Levels and Incidence of Adverse Reactions in Children with Mycoplasma Pneumonia

Objective

This study was designed to explore the efficacy of azithromycin plus glucocorticoid adjuvant therapy on the levels of serum inflammatory factors and the incidence of adverse reactions in children with mycoplasma pneumonia.

Method

A total of 90 eligible children with mycoplasma pneumonia in our hospital from January 2019 to January 2020 were recruited. They were assigned to receive either azithromycin (control group) or azithromycin plus glucocorticoid (experimental group) according to the order of admission. Outcome measures included clinical efficacy, serum inflammatory factor indicators, lung function, clinical symptom mitigation, length of hospital stay, immune function, incidence of adverse reactions, and psychological status of the eligible children.

Results

Azithromycin plus glucocorticoid was associated with a significantly higher total clinical efficacy compared with azithromycin (P < 0.05). No significant differences were found in the serum inflammatory factor indices between the two groups (P > 0.05). The children given azithromycin plus glucocorticoid showed lower levels of serum inflammatory factors versus those given azithromycin alone (P < 0.001). Azithromycin plus glucocorticoid outperformed the monotherapy of azithromycin in terms of lung function (P < 0.001). Children after azithromycin plus glucocorticoid therapy had a faster clinical symptom disappearance and shorter length of hospital stay compared with after azithromycin alone (P < 0.001). Azithromycin plus glucocorticoid resulted in higher levels of immune function indices compared with azithromycin alone (P < 0.001). Azithromycin plus glucocorticoid was associated with a lower incidence of adverse reactions compared with azithromycin (P < 0.05). Lower Children's Depression Inventory (CDI) scores were witnessed in children given azithromycin plus glucocorticoid compared with monotherapy of azithromycin (P < 0.001).

Conclusion

Azithromycin plus glucocorticoid in children with mycoplasma pneumonia can effectively improve the clinical indicators of the children with promising efficacy and high safety, which is worthy of promotion and application.

Hydrocortisone Long-term Treatment Effect on Immunomodulatory Properties of Human Adipose-Derived Mesenchymal Stromal/Stem Cells

Cortisol is secreted in prolonged stress and has therapeutic effects in inflammatory diseases. Considering the immunomodulatory effects of mesenchymal stem cells, here we investigated the effect of hydrocortisone (HC) long-term treatment on immunomodulatory properties of human adipose-derived mesenchymal stromal/stem cells (ASCs). Isolated ASCs from healthy subjects were treated with different HC concentrations for 14 days. The effect of HC-treated ASCs on the proliferative response of peripheral blood mononuclear cells (PBMCs) was evaluated in ASCs/2-way mixed leukocyte reaction coculture using 2,3-bis-(2-methoxy-4-nitro-5-sulfophenyl)-2H-tetrazolium-5-carboxanilide (XTT)-assay. HC-treated ASCs were further divided into interferon gamma (IFN-γ) stimulated and unstimulated groups. Transforming growth factor beta 1 (TGF-β1) and interleukin (IL)-6 levels were measured in culture supernatants by enzyme-linked immunosorbent assay. Relative expression of cyclooxygenase-2 (COX-2), hepatocyte growth factor, indoleamine dioxygenase, and programmed death-ligand 1 genes was assessed by real-time PCR. Levels of TGF-β1 and COX-2 expression were elevated in unstimulated ASCs, while exposure to high concentration of HC significantly increased TGF-β1 levels and reduced COX-2 expression. Unstimulated HC-5-μM-treated ASCs increased PBMC proliferation ratio on day 2 of coculture compared to the control group (P = 0.05). In IFN-γ stimulated condition, pretreatment with HC-5 μM resulted in a significantly increased IL-6 and significantly decreased COX-2 expression compared to the HC untreated control group. In conclusion, our results showed various alterations of ASC immunomodulatory related features as a result of long-term exposure of different concentrations of HC. It seems that HC at low concentration pushed the balance toward extended immune response in ASCs, while this observation wasn't persistent in ASCs treated with higher concentrations of HC.

The Glucocorticoid Receptor in Osterix-Expressing Cells Regulates Bone Mass, Bone Marrow Adipose Tissue, and Systemic Metabolism in Female Mice During Aging

Hallmarks of aging-associated osteoporosis include bone loss, bone marrow adipose tissue (BMAT) expansion, and impaired osteoblast function. Endogenous glucocorticoid levels increase with age, and elevated glucocorticoid signaling, associated with chronic stress and dysregulated metabolism, can have a deleterious effect on bone mass. Canonical glucocorticoid signaling through the glucocorticoid receptor (GR) was recently investigated as a mediator of osteoporosis during the stress of chronic caloric restriction. To address the role of the GR in an aging-associated osteoporotic phenotype, the current study utilized female GR conditional knockout (GR-CKO; GR^fl/fl :Osx-Cre+) mice and control littermates on the C57BL/6 background aged to 21 months and studied in comparison to young (3- and 6-month-old) mice. GR deficiency in Osx-expressing cells led to low bone mass and BMAT accumulation that persisted with aging. Surprisingly, however, GR-CKO mice also exhibited alterations in muscle mass (reduced % lean mass and soleus fiber size), accompanied by reduced voluntary physical activity, and also exhibited higher whole-body metabolic rate and elevated blood pressure. Moreover, increased lipid storage was observed in GR-CKO osteoblastic cultures in a glucocorticoid-dependent fashion despite genetic deletion of the GR, and could be reversed via pharmacological inhibition of the mineralocorticoid receptor (MR). These findings provide evidence of a role for the GR (and possibly the MR) in facilitating healthy bone maintenance with aging in females. The effects of GR-deficient bone on whole-body physiology also demonstrate the importance of bone as an endocrine organ and suggest evidence for compensatory mechanisms that facilitate glucocorticoid signaling in the absence of osteoblastic GR function; these represent new avenues of research that may improve understanding of glucocorticoid signaling in bone toward the development of novel osteogenic agents. © 2021 American Society for Bone and Mineral Research (ASBMR).

Current status of glucocorticoid usage in solid organ transplantation

Glucocorticoids (GCs) have been the mainstay of immunosuppressive therapy in solid organ transplantation (SOT) for decades, due to their potent effects on innate immunity and tissue protective effects. However, some SOT centers are reluctant to administer GCs long-term because of the various related side effects. This review summarizes the advantages and disadvantages of GCs in SOT. PubMed and Scopus databases were searched from 2011 to April 2021 using search syntaxes covering “transplantation” and “glucocorticoids”. GCs are used in transplant recipients, transplant donors, and organ perfusate solution to improve transplant outcomes. In SOT recipients, GCs are administered as induction and maintenance immunosuppressive therapy. GCs are also the cornerstone to treat acute antibody- and T-cell-mediated rejections. Addition of GCs to organ perfusate solution and pretreatment of transplant donors with GCs are recommended by some guidelines and protocols, to reduce ischemia-reperfusion injury peri-transplant. GCs with low bioavailability and high potency for GC receptors, such as budesonide, nanoparticle-mediated targeted delivery of GCs to specific organs, and combination use of dexamethasone with inducers of immune-regulatory cells, are new methods of GC application in SOT patients to reduce side effects or induce immune-tolerance instead of immunosuppression. Various side effects involving different non-targeted organs/tissues, such as bone, cardiovascular, neuromuscular, skin and gastrointestinal tract, have been noted for GCs. There are also potential drug-drug interactions for GCs in SOT patients.

Glucocorticoid/Adiponectin Axis Mediates Full Activation of Cold-Induced Beige Fat Thermogenesis

Glucocorticoids (GCs), a class of corticosteroids produced by the adrenal cortex in response to stress, exert obesity-promoting effects. Although adaptive thermogenesis has been considered an effective approach to counteract obesity, whether GCs play a role in regulating cold stress-induced thermogenesis remains incompletely understood. Here, we show that the circulating levels of stress hormone corticosterone (GC in rodents) were significantly elevated, whereas the levels of adiponectin, an adipokine that was linked to cold-induced adaptive thermogenesis, were decreased 48 h post cold exposure. The administration of a glucocorticoid hydrocortisone downregulated adiponectin protein and mRNA levels in both WAT and white adipocytes, and upregulated thermogenic gene expression in inguinal fat. In contrast, mifepristone, a glucocorticoid receptor antagonist, enhanced adiponectin expression and suppressed energy expenditure in vivo. Mechanistically, hydrocortisone suppressed adiponectin expression by antagonizing PPARγ in differentiated 3T3-L1 adipocytes. Ultimately, adiponectin deficiency restored mifepristone-decreased oxygen consumption and suppressed the expression of thermogenic genes in inguinal fat. Taken together, our study reveals that the GCs/adiponectin axis is a key regulator of beige fat thermogenesis in response to acute cold stress.

Carbonyl reductase 1 amplifies glucocorticoid action in adipose tissue and impairs glucose tolerance in lean mice

OBJECTIVE

Carbonyl reductase 1 (Cbr1), a recently discovered contributor to tissue glucocorticoid metabolism converting corticosterone to 20β-dihydrocorticosterone (20β-DHB), is upregulated in adipose tissue of obese humans and mice and may contribute to cardiometabolic complications of obesity. This study tested the hypothesis that Cbr1-mediated glucocorticoid metabolism influences glucocorticoid and mineralocorticoid receptor activation in adipose tissue and impacts glucose homeostasis in lean and obese states.

METHODS

The actions of 20β-DHB on corticosteroid receptors in adipose tissue were investigated first using a combination of in silico, in vitro, and transcriptomic techniques and then in vivo administration in combination with receptor antagonists. Mice lacking one Cbr1 allele and mice overexpressing Cbr1 in their adipose tissue underwent metabolic phenotyping before and after induction of obesity with high-fat feeding.

RESULTS

20β-DHB activated both the glucocorticoid and mineralocorticoid receptor in adipose tissue and systemic administration to wild-type mice induced glucose intolerance, an effect that was ameliorated by both glucocorticoid and mineralocorticoid receptor antagonism. Cbr1 haploinsufficient lean male mice had lower fasting glucose and improved glucose tolerance compared with littermate controls, a difference that was abolished by administration of 20β-DHB and absent in female mice with higher baseline adipose 20β-DHB concentrations than male mice. Conversely, overexpression of Cbr1 in adipose tissue resulted in worsened glucose tolerance and higher fasting glucose in lean male and female mice. However, neither Cbr1 haploinsfficiency nor adipose overexpression affected glucose dyshomeostasis induced by high-fat feeding.

CONCLUSIONS

Carbonyl reductase 1 is a novel regulator of glucocorticoid and mineralocorticoid receptor activation in adipose tissue that influences glucose homeostasis in lean mice.

Obesity-induced excess of 17-hydroxyprogesterone promotes hyperglycemia through activation of glucocorticoid receptor

Type 2 diabetes mellitus (T2DM) has become an expanding global public health problem. Although the glucocorticoid receptor (GR) is an important regulator of glucose metabolism, the relationship between circulating glucocorticoids (GCs) and the features of T2DM remains controversial. Here, we show that 17-hydroxyprogesterone (17-OHP), an intermediate steroid in the biosynthetic pathway that converts cholesterol to cortisol, binds to and stimulates the transcriptional activity of GR. Hepatic 17-OHP concentrations are increased in diabetic mice and patients due to aberrantly increased expression of Cyp17A1. Systemic administration of 17-OHP or overexpression of Cyp17A1 in the livers of lean mice promoted the pathogenesis of hyperglycemia and insulin resistance, whereas knockdown of Cyp17A1 abrogated metabolic disorders in obese mice. Therefore, our results identify a Cyp17A1/17-OHP/GR-dependent pathway in the liver that mediates obesity-induced hyperglycemia, suggesting that selectively targeting hepatic Cyp17A1 may provide a therapeutic avenue for treating T2DM.

Molecular Mechanisms of Glucocorticoid-Induced Insulin Resistance

Glucocorticoids (GCs) are steroids secreted by the adrenal cortex under the hypothalamic-pituitary-adrenal axis control, one of the major neuro-endocrine systems of the organism. These hormones are involved in tissue repair, immune stability, and metabolic processes, such as the regulation of carbohydrate, lipid, and protein metabolism. Globally, GCs are presented as ‘flight and fight’ hormones and, in that purpose, they are catabolic hormones required to mobilize storage to provide energy for the organism. If acute GC secretion allows fast metabolic adaptations to respond to danger, stress, or metabolic imbalance, long-term GC exposure arising from treatment or Cushing’s syndrome, progressively leads to insulin resistance and, in fine, cardiometabolic disorders. In this review, we briefly summarize the pharmacological actions of GC and metabolic dysregulations observed in patients exposed to an excess of GCs. Next, we describe in detail the molecular mechanisms underlying GC-induced insulin resistance in adipose tissue, liver, muscle, and to a lesser extent in gut, bone, and brain, mainly identified by numerous studies performed in animal models. Finally, we present the paradoxical effects of GCs on beta cell mass and insulin secretion by the pancreas with a specific focus on the direct and indirect (through insulin-sensitive organs) effects of GCs. Overall, a better knowledge of the specific action of GCs on several organs and their molecular targets may help foster the understanding of GCs’ side effects and design new drugs that possess therapeutic benefits without metabolic adverse effects.

The Ubiquitin Ligase SIAH2 Negatively Regulates Glucocorticoid Receptor Activity and Abundance

Glucocorticoids are clinically essential drugs used routinely to control inflammation. However, a host of metabolic side effects manifests upon usage beyond a few days. In the present study, we tested the hypothesis that seven-in-absentia mammalian homolog-2 (SIAH2), a ubiquitin ligase that regulates adipogenesis, is important for controlling adipocyte size, inflammation, and the ability of adipose tissue to expand in response to a glucocorticoid challenge. Using mice with global deletion of SIAH2 exposed or not to corticosterone, we found that adipocytes are larger in response to glucocorticoids in the absence of SIAH2. In addition, SIAH2 regulates glucocorticoid receptor (GR) transcriptional activity and total GR protein abundance. Moreover, these studies reveal that there is an increased expression of genes involved in fibrosis and inflammatory signaling pathways found in white adipose tissue in response to glucocorticoids in the absence of SIAH2. In summary, this is the first study to identify a role for SIAH2 to regulate transcriptional activity and abundance of the GR, which leads to alterations in adipose tissue size and gene expression during in vivo exposure to glucocorticoids.

Endogenous Glucocorticoid Signaling in the Regulation of Bone and Marrow Adiposity: Lessons from Metabolism and Cross Talk in Other Tissues

PURPOSE OF REVIEW

The development of adiposity in the bone marrow, known as marrow adipose tissue (MAT), is often associated with musculoskeletal frailty. Glucocorticoids, which are a key component of the biological response to stress, affect both bone and MAT. These molecules signal through receptors such as the glucocorticoid receptor (GR), but the role of the GR in regulation of MAT is not yet clear from previous studies. The purpose of this review is to establish and determine the role of GR-mediated signaling in marrow adiposity by comparing and contrasting what is known against other energy-storing tissues like adipose tissue, liver, and muscle, to provide better insight into the regulation of MAT during times of metabolic stress (e.g., dietary challenges, aging).

RECENT FINDINGS

GR-mediated glucocorticoid signaling is critical for proper storage and utilization of lipids in cells such as adipocytes and hepatocytes and proteolysis in muscle, impacting whole-body composition, energy utilization, and homeostasis through a complex network of tissue cross talk between these systems. Loss of GR signaling in bone promotes increased MAT and decreased bone mass. GR-mediated signaling in the liver, adipose tissue, and muscle is critical for whole-body energy and metabolic homeostasis, and both similarities and differences in GR-mediated GC signaling in MAT as compared with these tissues are readily apparent. It is clear that GC-induced pathways work together through these tissues to affect systemic biology, and understanding the role of bone in these patterns of tissue cross talk may lead to a better understanding of MAT-bone biology that improves treatment strategies for frailty-associated diseases.

Adipocyte-derived Periostin mediates glucocorticoid-induced hepatosteatosis in mice

Objective

Long-term glucocorticoids (GCs) therapy usually causes many metabolic side effects, including fatty liver. However, the molecular mechanisms remain poorly understood. Herein, we explored the molecular basis of GCs in the development of fatty liver.

Methods

C57BL/6 male mice were injected with Dexamethasone (DEX) while mouse primary hepatocytes (MPHs), HepG2 and Hep1-6 cells were cultured in the presence of DEX. Genes expression in liver tissues and hepatocytes were assessed by quantitative real-time PCR and western blotting, respectively. To explore whether Periostin is involved in the development of GCs-induced fatty liver, wild-type and Periostin knockout mice were treated with DEX or vehicle control. Luciferase reporter and chromatin immunoprecipitation assays were used to determine the regulatory roles of GCs on Periostin expression.

Results

We show that treatment of dexamethasone (DEX), a synthetic analog of GCs, led to the accumulation of triglycerides in the livers of mice, but not in cultured hepatocytes, suggesting that GCs may promote liver steatosis through integrative organ crosstalk mediated by systemic factors. We further found that DEX upregulated the expression levels of Periostin in white adipose tissues, which in turn promoted liver steatosis. Administration of a Periostin-neutralizing antibody or genetic ablation of Periostin largely attenuated DEX-induced hepatic steatosis in mice.

Conclusions

Our findings provided a novel insight that GCs could promote liver steatosis through integrative organ crosstalk mediated by white fat-secreted Periostin. These results establish Periostin as an endocrine factor with therapeutic potential for the treatment of GCs-associated fatty liver.

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Dexamethasone (DEX) treatment led to triglycerides accumulation in the liver of mice, but not in cultured hepatocytes.

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DEX treatment upregulates Periostin in white adipose tissues, which in turn induces liver steatosis in mice.

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Genetic ablation or pharmacological inhibition of Periostin partially attenuated DEX -induced hepatic steatosis in mice.

Impact of HIV/simian immunodeficiency virus infection and viral proteins on adipose tissue fibrosis and adipogenesis

OBJECTIVE

HIV-infected patients receiving antiretroviral treatment (ART) often present adipose tissue accumulation and/or redistribution. adipose tissue has been shown to be an HIV/SIV reservoir and viral proteins as Tat or Nef can be released by infected immune cells and exert a bystander effect on adipocytes or precursors. Our aim was to demonstrate that SIV/HIV infection per se could alter adipose tissue structure and/or function.

DESIGN

Morphological and functional alterations of subcutaneous (SCAT) and visceral adipose tissue (VAT) were studied in SIV-infected macaques and HIV-infected ART-controlled patients. To analyze the effect of Tat or Nef, we used human adipose stem cells (ASCs) issued from healthy donors, and analyzed adipogenesis and extracellular matrix component production using two dimensional (2D) and three-dimensional (3D) culture models.

METHODS

Adipocyte size and index of fibrosis were determined on Sirius red-stained adipose tissue samples. Proliferating and adipocyte 2D-differentiating or 3D-differentiating ASCs were treated chronically with Tat or Nef. mRNA, protein expression and secretion were examined by RT-PCR, western-blot and ELISA.

RESULTS

SCAT and VAT from SIV-infected macaques displayed small adipocytes, decreased adipogenesis and severe fibrosis with collagen deposition. SCAT and VAT from HIV-infected ART-controlled patients presented similar alterations. In vitro, Tat and/or Nef induced a profibrotic phenotype in undifferentiated ASCs and altered adipogenesis and collagen production in adipocyte-differentiating ASCs.

CONCLUSION

We demonstrate here a specific role for HIV/SIV infection per se on adipose tissue fibrosis and adipogenesis, probably through the release of viral proteins, which could be involved in adipose tissue dysfunction contributing to cardiometabolic alterations of HIV-infected individuals.

Metabolic Abnormalities of Chronic High-Dose Glucocorticoids Are Not Mediated by Hypothalamic AgRP in Male Mice

Glucocorticoids are potent and widely used medicines but often cause metabolic side effects. A murine model of corticosterone treatment resulted in increased hypothalamic expression of the melanocortin antagonist AgRP in parallel with obesity and hyperglycemia. We investigated how these adverse effects develop over time, with particular emphasis on hypothalamic involvement. Wild-type and Agrp-/- male mice were treated with corticosterone for 3 weeks. Phenotypic, biochemical, protein, and mRNA analyses were undertaken on central and peripheral tissues, including white and brown adipose tissue, liver, and muscle, to determine the metabolic consequences. Corticosterone treatment induced hyperphagia within 1 day in wild-type mice, which persisted for 3 weeks. Despite this early increase in food intake, the body weight only started to increase after 10 days. Hyperinsulinemia occurred at day 1. Also, although after 2 days, alterations were present in the genes often associated with insulin resistance in several peripheral tissues, hyperglycemia only developed at 3 weeks. Throughout, sustained elevation in hypothalamic Agrp expression was present. Mice with Agrp deleted [using clustered regularly interspaced short palindromic repeats (CRISPR)-Cas9, Agrp-/-] were partially protected against corticosterone-induced hyperphagia. However, Agrp-/- mice still had corticosterone-induced increases in body weight and adiposity similar to those of the Agrp+/+ mice. Loss of Agrp did not diminish corticosterone-induced hyperinsulinemia or correct changes in hepatic gluconeogenic genes. Chronic glucocorticoid treatment in mice mimics many of the metabolic side effects seen in patients and leads to a robust increase in Agrp. However, AgRP does not appear to be responsible for most of the glucocorticoid-induced adverse metabolic effects.