Stimulation of Th2 response by high doses of dehydroepiandrosterone in KLH-primed splenocytes

The Effects of Neuroactive Steroids on Myelin in Health and Disease

Myelin plays a pivotal role in the efficient transmission of nerve impulses. Disruptions in myelin integrity are associated with numerous neurological disorders, including multiple sclerosis. In the central nervous system (CNS), myelin is formed by oligodendrocytes. Remyelination refers to the re-formation of the damaged myelin sheath by newly formed oligodendrocytes. Steroids have gained attention for their potential modulatory effects on myelin in both health and disease. Steroids are traditionally associated with endocrine functions, but their local synthesis within the nervous system has generated significant interest. The term "neuroactive steroids" refers to steroids that can act on cells of the nervous system. In the healthy state, neuroactive steroids promote myelin formation, maintenance, and repair by enhancing oligodendrocyte differentiation and maturation. In pathological conditions, such as demyelination injury, multiple neuroactive steroids have shown promise in promoting remyelination. Understanding the effects of neuroactive steroids on myelin could lead to novel therapeutic approaches for demyelinating diseases and neurodegenerative disorders. This review highlights the potential therapeutic significance of neuroactive steroids in myelin-related health and diseases. We review the synthesis of steroids by neurons and glial cells and discuss the roles of neuroactive steroids on myelin structure and function in health and disease. We emphasize the potential promyelinating effects of the varying levels of neuroactive steroids during different female physiological states such as the menstrual cycle, pregnancy, lactation, and postmenopause.

ENT-A010, a Novel Steroid Derivative, Displays Neuroprotective Functions and Modulates Microglial Responses

Tackling neurodegeneration and neuroinflammation is particularly challenging due to the complexity of central nervous system (CNS) disorders, as well as the limited drug accessibility to the brain. The activation of tropomyosin-related kinase A (TRKA) receptor signaling by the nerve growth factor (NGF) or the neurosteroid dehydroepiandrosterone (DHEA) may combat neurodegeneration and regulate microglial function. In the present study, we synthesized a C-17-spiro-cyclopropyl DHEA derivative (ENT-A010), which was capable of activating TRKA. ENT-A010 protected PC12 cells against serum starvation-induced cell death, dorsal root ganglia (DRG) neurons against NGF deprivation-induced apoptosis and hippocampal neurons against Aβ-induced apoptosis. In addition, ENT-A010 pretreatment partially restored homeostatic features of microglia in the hippocampus of lipopolysaccharide (LPS)-treated mice, enhanced Aβ phagocytosis, and increased Ngf expression in microglia in vitro. In conclusion, the small molecule ENT-A010 elicited neuroprotective effects and modulated microglial function, thereby emerging as an interesting compound, which merits further study in the treatment of CNS disorders.

Does dehydroepiandrosterone sulfate have a role in COVID-19 prognosis and treatment?

The pathophysiology of COVID comprises an exaggerated pro-inflammatory response. Hypothalamic-pituitary-adrenal (HPA) axis has a crucial role in various inflammatory conditions and modulated immunological response. Limited evidence is available regarding the incidence and the effect of HPA dysfunction in COVID-19. Although the cortisol levels have only been estimated in a few studies, the dehydroepiandrosterone sulfate (DHEAS) release from the adrenal gland has not been explored yet. In this mini review, the authors discuss the role of dehydroepiandrosterone (DHEA) and DHEAS in the acute stress response and immunological modulation. Various effects of DHEAS have been demonstrated in different diseases. The specific inhibitory effect of DHEA on interleukin 6 (IL-6) could be of paramount importance in COVID-19. Further, DHEA supplementation has already been proposed in inflammatory conditions, like rheumatoid arthritis. DHEAS levels in COVID-19 may help to understand the HPA axis dysfunction as well as the possibility of repurposing DHEA as a drug for mitigating the pro-inflammatory COVID-19.

Clusterin regulates macrophage expansion, polarization and phagocytic activity in response to inflammation in the kidneys

Clusterin (CLU) is a multifunctional protein localized extracellularly and intracellularly. Although CLU-knockout (KO) mice are more susceptible to renal ischemia-reperfusion injury (IRI), the mechanisms underlying the actions of CLU in IRI are not fully understood. Macrophages are key regulators of IRI severity and tissue repair. Therefore, we investigated the role of CLU in macrophage polarization and phagocytosis. Renal IRI was induced in wild-type (WT) or CLU-KO C57BL/6 mice by clamping the renal pedicles for 30 min at 32°C. Peritoneal macrophages were activated via an intraperitoneal injection of lipopolysaccharide (LPS). Renal tissue damage was examined using histology, whereas leukocyte phenotypes were assessed using flow cytometry and immunohistochemistry. We found that monocytes/macrophages expressed the CLU protein that was upregulated by hypoxia. The percentages of macrophages (F4/80⁺ , CD11b⁺ or MAC3⁺ ) infiltrating the kidneys of WT mice were significantly less than those in CLU-KO mice after IRI. The M1/M2 phenotype ratio of the macrophages in WT kidneys decreased at day 7 post-IRI when the injury was repaired, whereas that in KO kidneys increased consistently as tissue injury persisted. In response to LPS stimulation, WT mice produced fewer M1 macrophages, but not M2, than the control did. Phagocytosis was stimulated by CLU expression in macrophages compared with the CLU null controls and by the exogenous CLU protein. In conclusion, CLU suppresses macrophage infiltration and proinflammatory M1 polarization during the recovery period following IRI, and enhances phagocytic activity, which may be partly responsible for tissue repair in the kidneys of WT mice after injury.

DHEA inhibits acute microglia-mediated inflammation through activation of the TrkA-Akt1/2-CREB-Jmjd3 pathway

Dehydroepiandrosterone (DHEA) is the most abundant circulating steroid hormone in humans, produced by the adrenals, the gonads and the brain. DHEA was previously shown to bind to the nerve growth factor receptor, tropomyosin-related kinase A (TrkA), and to thereby exert neuroprotective effects. Here we show that DHEA reduces microglia-mediated inflammation in an acute lipopolysaccharide-induced neuro-inflammation model in mice and in cultured microglia in vitro. DHEA regulates microglial inflammatory responses through phosphorylation of TrkA and subsequent activation of a pathway involving Akt1/Akt2 and cAMP response element-binding protein. The latter induces the expression of the histone 3 lysine 27 (H3K27) demethylase Jumonji d3 (Jmjd3), which thereby controls the expression of inflammation-related genes and microglial polarization. Together, our data indicate that DHEA-activated TrkA signaling is a potent regulator of microglia-mediated inflammation in a Jmjd3-dependent manner, thereby providing the platform for potential future therapeutic interventions in neuro-inflammatory pathologies.

Relationship of clusterin with renal inflammation and fibrosis after the recovery phase of ischemia-reperfusion injury

Background

Long-term outcomes after acute kidney injury (AKI) include incremental loss of function and progression towards chronic kidney disease (CKD); however, the pathogenesis of AKI to CKD remains largely unknown. Clusterin (CLU) is a chaperone-like protein that reduces ischemia-reperfusion injury (IRI) and enhances tissue repair after IRI in the kidney. This study investigated the role of CLU in the transition of IRI to renal fibrosis.

Methods

IRI was induced in the left kidneys of wild type (WT) C57BL/6J (B6) versus CLU knockout (KO) B6 mice by clamping the renal pedicles for 28 min at the body temperature of 32 °C. Tissue damage was examined by histology, infiltrate phenotypes by flow cytometry analysis, and fibrosis-related gene expression by PCR array.

Results

Reduction of kidney weight was induced by IRI, but was not affected by CLU KO. Both WT and KO kidneys had similar function with minimal cellular infiltration and fibrosis at day 14 of reperfusion. After 30 days, KO kidneys had greater loss in function than WT, indicated by the higher levels of both serum creatinine and BUN in KO mice, and exhibited more cellular infiltration (CD8 cells and macrophages), more tubular damage and more severe tissue fibrosis (glomerulopathy, interstitial fibrosis and vascular fibrosis). PCR array showed the association of CLU deficiency with up-regulation of CCL12, Col3a1, MMP9 and TIMP1 and down-regulation of EGF in these kidneys.

Conclusion

Our data suggest that CLU deficiency worsens renal inflammation and tissue fibrosis after IRI in the kidney, which may be mediated through multiple pathways.

Electronic supplementary material

The online version of this article (doi:10.1186/s12882-016-0348-x) contains supplementary material, which is available to authorized users.

Dehydroepiandrosterone (DHEA) restrains intestinal inflammation by rendering leukocytes hyporesponsive and balancing colitogenic inflammatory responses

Dehydroepiandrosterone (DHEA) is a hormone that plays an important role in the modulation of inflammatory responses. However, the precise mechanisms that link the actions of this androgen with protection or susceptibility to inflammatory bowel diseases (IBD) remain uknown. Here we showed that low dose DHEA inhibited proliferation of spleen cells and IFN-у production. The hormone was not toxic to myeloid lineage cells, although it caused necrosis of spleen cells at the intermediate and highest doses in vitro (50 and 100μM). The treatment of C57BL/6 mice with DHEA during colitis induction by dextran sodium sulfate (DSS) led to a reduction in weight loss and clinical signs of disease. There were decreased peripheral blood monocytes on day 6 of DSS exposure and treatment, besides increase in circulating neutrophils in the tissue repair phase. DHEA also led to reduced lamina propria cellularity and restoration of normal colon length. These results were accompanied by decreased expression of IL-6 and TGF-β mRNA, while IL-13 was augmented in the colon on day 6, which was probably related to attenuation of inflammation. There was retention of CD4(+) cells in the spleen after use of DHEA, along with augmented frequency of CD4(+)IL-4(+) cells, decreased CD4(+)IFN-ɣ(+) in spleen and constrained CD4(+)IL-17(+) population in the mesenteric lymph nodes. Moreover, splenocytes of mice treated with DHEA became hyporesponsive, as observed by reduced proliferation after re-stimulation ex-vivo. In conclusion, DHEA modifyies leukocyte activity and balances the exacerbated immune responses which drive local and systemic damages in IBD.

Halofuginone Synergistically Enhances Anti-Proliferation of Rapamycin in T Cells and Reduces Cytotoxicity of Cyclosporine in Cultured Renal Tubular Epithelial Cells

Both rapamycin (RAPA) and cyclosporin A (CsA) are commonly used for immunosuppression, however their adverse side effects limit their application. Thus, it is of interest to develop novel means to enhance or preserve the immunosuppressive activity of RAPA or CsA while reducing their toxicity. Halofuginone (HF) has been recently tested as a potential immunosuppressant. This study investigated the interaction of HF with RAPA or with CsA in cell cultures. Cell proliferation in cultures was determined using methylthiazol tetrazolium assay, and cell apoptosis assessed by flow cytometric analysis and Western blot. The drug-drug interaction was determined according to Loewe’s equation or Bliss independence. Here, we showed that addition of HF to anti-CD 3 antibody-stimulated splenocyte cultures induced synergistic suppression of T cell proliferation in the presence of RAPA, indicated by an interaction index (γ) value of < 1.0 between HF and RAPA, but not in those with CsA. The synergistic interaction of RAPA with HF in the suppression of T cell proliferation was also seen in a mixed lymphocyte reaction and Jurkat T cell growth, and was positively correlated with an increase in cell apoptosis, but not with proline depletion. In cultured kidney tubular epithelial cells, HF attenuated the cytotoxicity of CsA. In conclusion, these data indicate that HF synergistically enhances anti-T cell proliferation of RAPA and reduces the nephrotoxicity of CsA in vitro, suggesting the potential use of HF for enhancing anti-T cell proliferation of RAPA and reducing CsA-mediated nephrotoxicity.

New insights into the protective effects of DHEA1)

Numerous studies investigated the effects of pharmacological doses of DHEA in animals. Among protective effects, antiglucocorticoid potencies, triggering and modulation of immunity and anticancerous effects were reported. Because DHEA levels decrease in aging humans, this steroid has been assayed as replacement therapy in elderly volunteers without striking evidence for beneficial effects. Examination of the investigations carried out in animals lead to suspect that, rather than DHEA, its metabolites produced in tissues could be responsible for some of the observed effects. Known as the "mother steroid", DHEA is a precursor for androgenic and estrogenic steroid hormones. In addition, DHEA is hydroxylated at the 7α position by the cytochrome P450 7B1 (CYP7B1), and the 7α-hydroxy-DHEA produced is a substrate for the 11β-hydroxysteroid dehydrogenase type 1 (11β-HSD1) which converts it into 7β-hydroxy-DHEA. Both 7-hydroxylated metabolites were shown to favor the onset of immunity in mice and the activation of memory T cells in humans. Other DHEA and testosterone-derived metabolites, namely epiandrosterone and 5α-androstane-3β,17β-diol, are also substrates for the CYP7B1 and their 7α-hydroxylated products were also converted into the 7β epimer by the 11β-HSD1. When assayed at doses 104 lower than DHEA, 7β-hydroxy-epiandrosterone was shown to shift the prostaglandin metabolism patterns from prostaglandin E2 (PGE2) to PGD2 production, thus triggering the resolution of inflammation. In addition, 7β-hydroxy-epiandrosterone (1 nM) exerted the same effects as tamoxifen (1 μM) on the proliferation of MCF-7 and MDA-231 human breast cancer cells. These findings suggest that the observed effects of 7β-hydroxy-epiandrosterone could be mediated by estrogen receptors. This overview of recent research implies that DHEA does not act directly and that its effects are due to its metabolites when produced in tissues. Treatments with DHEA should take into account the target tissue abilities to produce the desired metabolites through the two key enzymes, CYP7B1 and 11β-HSD1.

Asthma and dehydroepiandrosterone (DHEA): facts and hypotheses

Dehydroepiandrosterone (DHEA) is considered as an important immunomodulating and anti-inflammatory hormone. Despite the continuing interest in DHEA replacement therapy, our knowledge of its effects upon asthma is very limited. DHEA is able to reverse cytokine imbalances associated with asthma, may prevent and attenuate allergic inflammation in airways, and does not possess the undesirable side effects of glucocorticoids; therefore, it may be potentially applied in the treatment of asthma. The steroid-sparing effect observed with DHEA clinically could appear especially favorable in asthmatic patients receiving oral treatment and those inhaling high doses of glucocorticoids. In addition, DHEA and its analogs might prove useful in reversing relative glucocorticoids insensitivity in patients with corticosteroid-resistant asthma. In this review we have focused specifically on DHEA's role in asthma.

Corticosterone evaluation in Wistar rats infected with the Y strain of Trypanosoma cruzi during the chronic phase

Understanding the mechanisms responsible for mediating the effects of stress on Trypanosoma cruzi infection is crucial for determining the full impact of stress on Chagas' disease and for devising effective interventions. Dehydroepiandrosterone (DHEA), a steroid hormone synthesized from pregnenolone, is secreted by the adrenal cortex in response to stress. Although its physiologic role has not been fully defined, DHEA has been shown to modulate immune function. In the present study, we evaluated the levels of corticosterone and the ability of T. cruzi infection to modulate the expression of Th2 cytokines in Wistar rats with chronic Chagas' disease submitted to repetitive stress. The animals submitted to stress displayed enhanced levels of corticosterone as compared to control counterparts. Stress and infection triggered the most elevated concentrations of corticosterone. DHEA significantly reduced corticosterone levels for infected and stressed animals with DHEA. The infected animals displayed enhanced levels of IL-10 and IL-4 as compared to control ones. Stress combined with infection triggered the higher levels of IL-10 and IL-4. DHEA alone and combined with infection and stress significantly increased IL-10 and IL-4 levels. Then, this study might provide additional clues about factors that regulate some of the immunoregulatory aspects of T. cruzi infection and might offer new opportunities for therapeutic interventions.

Dehydroepiandrosterone as a regulator of immune cell function

Dehydroepiandrosterone (DHEA) is a C19 steroid of adrenal origin. Notably, its secretion declines with age, a phenomenon referred to as the "adrenopause". For many years, the physiological significance of DHEA remained elusive. However, many studies have now shown that DHEA has significant immune modulatory function, exhibiting both immune stimulatory and anti-glucocorticoid effects. Although several of these studies are limited by the fact that they were carried out in rodents, who are incapable of adrenal DHEA production, and therefore have very low circulating levels of this steroid, evidence from the study of immune cells is now accumulating to suggest a role for DHEA in regulating human immunity. This ability to regulate immune function has raised interest in the therapeutic potential of DHEA as a treatment for the immunological abnormalities that arise in subjects with low circulating levels of this hormone. This has included attempts at reversing the impaired immune response of older individuals to vaccination and restoring immune regulation in patients with chronic autoimmune disease. This review summarises the reported effects of DHEA on immune function and discusses the therapeutic potential of this steroid in geriatric medicine and particularly in age-related disease with an immune component.

Dehydroepiandrosterone to induce murine models for the study of polycystic ovary syndrome

During the last decade a battery of animal models used for the study of polycystic ovary syndrome (PCOS) have allowed a focus on different aspects of the pathology. Since dehydroepiandrosterone (DHEA) was found to be one of the most abundant circulating androgens in women with PCOS, a rodent model showing the salient features found in women with PCOS was developed by the injection of DHEA. Although insulin-sensitizing agents, such as biguanides, are clinically used in the treatment of diabetes and PCOS, the complete understanding of their mechanisms of action remains unknown. The present review discusses the molecular mechanisms involved in the development of PCOS by using the DHEA-PCOS murine model and analyzes the role of the biguanide metformin as treatment.

DHEA-dependent and organ-specific regulation of TNF-alpha mRNA expression in a murine polymicrobial sepsis and trauma model

Introduction

Dehydroepiandrosterone (DHEA) improves survival after trauma and sepsis, while mechanisms of action are not yet fully understood. Therefore, we investigated the influence of DHEA on local cytokine expression in a two-hit model.

Methods

Male NMRI mice were subjected to femur fracture/hemorrhagic shock and subsequent sepsis. Sham-operated animals were used as controls. DHEA (25 mg/kg) or vehicle was administered daily. Mortality rate, activity and body temperature were determined daily after sepsis induction. TNF-α, IL-1β and IL-10 mRNA expression pattern were investigated in lung and liver tissue after 48 and 96 hours.

Results

DHEA treatment resulted in a significantly reduced mortality rate and improvements in the clinical status. On cytokine level, only TNF-α was significantly reduced in the cecal ligation and puncture (CLP)-vehicle group in both tissues after 48 hours. This suppression could be restored by DHEA administration. In contrast, after 96 hours, TNF-α was up-regulated in the CLP-vehicle group while remaining moderate by DHEA treatment in liver tissue.

Conclusions

The improved outcome after DHEA treatment and trauma is coherent with restoration of TNF-α in liver and lung after 48 hours and a counter-regulatory attenuation of TNF-α in liver after 96 hours. Thus, DHEA seems to act, time and organ dependent, as a potent modulator of TNF-α expression.

Effects of combined bacille Calmette-Guérin and dehydroepiandrosterone treatment on established asthma in mice

Both bacille Calmette-Guerin (BCG) and dehydroepiandrosterone induce Th1 immune responses and suppress Th2 allergic reactions. To investigate whether a combined administration of BCG and dehydroepiandrosterone treat asthma more effectively, BALB/c mice (n = 8 per group) with established airway hyper-responsiveness were treated with BCG and/or dehydroepiandrosterone. Combined treatment with 2 x 10(5) colony-forming units (CFUs) of BCG and 0.01% dehydroepiandrosterone was the most effective one at suppressing eosinophilia in bronchoalveolar lavage fluids. In addition, this combination also was better at suppressing hypersensitivity as compared to BCG alone (13.7 +/- 4.0- versus 3.6 +/- 0.5-fold increase in the sensitivity index; P < .05) in male mice. Similarly, the effect of the combined treatment was superior to that of individual treatments at decreasing the serum ovalbumin-specific immunoglobulin E (IgE) level. However, the addition of 0.1% dehydroepiandrosterone to BCG significantly decreased the efficacy of BCG on hypersensitivity in female mice. In male mice, the suppressive effect of the treatments on hypersensitivity tended to be lower, and the baseline interferon-gamma /interleukin-5 (IFN-gamma /IL-5) ratio in the splenocyte supernatant was significantly higher as compared to female mice. In conclusion, treatment with an appropriate combination of BCG and dehydroepiandrosterone had additive therapeutic effects on mice with established asthma. Androgens in males and dehydroepiandrosterone overdose might reduce the efficacy of BCG.

Administration of dehydroepiandrosterone ameliorates experimental autoimmune neuritis in Lewis rats

Dehydroepiandrosterone (DHEA) is an abundant adrenal steroid in serum of humans, and has been reported to have anti-inflammatory, anti-proliferative, and certain immune-regulating properties. Experimental autoimmune neuritis (EAN) is a Th1 cell-mediated animal model of Guillain-Barré syndrome (GBS) in humans. In the present study, DHEA was administered subcutaneously to Lewis rats immunized with bovine peripheral myelin (BPM) in Freund's complete adjuvant. Rats treated with DHEA displayed significant delay in onset, decreased inflammatory cell infiltration in the PNS. Benefit was associated with significant decreases in numbers of IFN-gamma and TNF-alpha expressing cells in the PNS, BPM-stimulated T cell proliferation and IFN-gamma, TNF-alpha-secretion in the spleen cells. Only 2 mg DHEA-treated EAN rats decreased peak clinical score. No significant difference of supernatant IL-10 was found among the treatment and control groups. These results suggest that DHEA can ameliorate the severity of EAN by suppressing the proliferation of autoreactive T cell and expression of pro-inflammatory cytokines.

Effects of combined BCG and DHEA treatment in preventing the development of asthma

Both BCG and dehydroepiandrosterone (DHEA) induce Th1 immune responses and suppress Th2 allergic reactions. To investigate whether the combination of BCG and DHEA has an additive effect on asthma prevention, BALB/c mice (n = 10 per group) were given an intraperitoneal injection of BCG at the beginning of sensitization, and fed mice chow containing DHEA throughout the study. In female mice, the combined administration of 2 x 10(4) CFUs BCG and 0.01% DHEA effectively suppressed the ovalbumin-induced increase in airway sensitivity to methacholine (56.5 vs. 8.2 mg/mL, p < 0.01), while BCG (13.9 mg/mL) or DHEA (17.9 mg/mL) alone did not. However, the addition of high dose (0.1%) DHEA decreased the efficacy of high dose (2 x 10(5) CFUs) BCG in suppressing the airway responsiveness and eosinophilia. In male mice, the treatments with BCG and/or DHEA were less effective, and the interferon-gamma/interleukin-4 ratio in the splenocyte supernatant was significantly higher and the ovalbumin-specific IgE concentration in the serum was significantly lower as compared to female mice. In conclusion, the combination of low doses of BCG and DHEA had an additive effect in suppressing the development of airway hypersensitivity. Androgens in males and DHEA overdose might reduce the efficacy of BCG.

Dehydroepiandrosterone and metformin modulate progesterone-induced blocking factor (PIBF), cyclooxygenase 2 (COX2) and cytokines in early pregnant mice

The present study examined the mechanism by which metformin (N,N'-dimethylbiguanide) prevents embryonic resorption induced in mice by dehydroepiandrosterone (DHEA). Treatment with DHEA (60mg/kg, s.c. 24 and 48h post-implantation) induces embryo resorption of early pregnant BALB/c mice while simultaneous treatment with metformin (240mg/kg, oral 24 and 48h post-implantation) prevents it. During pregnancy progesterone-induced blocking factor (PIBF) modulates prostaglandins (PGs) and cytokine production. These findings prompted us to investigate the effect of DHEA and metformin on both PIBF and cyclooxygenase 2 (COX2) expressions at the implantation sites, as well as cytokine production. PIBF and COX2 expression were detected by immunohistochemistry from DHEA and DHEA+ metformin treated 8 days-pregnant mice and serum cytokine levels of these animals were determined by ELISA. DHEA treatment both abolished PIBF expression and increased COX2 expression. Embryo resorption correlates with the lack of PIBF expression, diminished IL-6 levels and increased IL-2 concentration while metformin was able to reverse the effect of DHEA on both PIBF and COX2 expression and IL-6 levels. We concluded that hyperandrogenization induces embryo resorption in early pregnancy diminishing PIBF in implantation sites, having a pro-inflammatory effect. Metformin is able to prevent such effects.

Dehydroepiandrosterone and metformin regulate proliferation of murine T lymphocytes

The aim of the present study was to assess the effect of dehydroepiandrosterone (DHEA: 10 microM) and metformin (10 microM and 100 microM) in regulating proliferation of cultured T lymphocytes. T cells were isolated from lymph nodes of prepuberal BALB/c mice. We found that DHEA, metformin and DHEA + metformin added to the incubation media diminished proliferation of T cells. The inhibition by DHEA was higher than that produced by metformin, while the combined treatment showed a synergistic action that allowed us to speculate distinct regulatory pathways. This was supported later by other findings in which the addition of DHEA to the incubation media did not modify T lymphocyte viability, while treatment with metformin and DHEA + metformin diminished cellular viability and increased both early and late apoptosis. Moreover, DHEA diminished the content of the anti-oxidant molecule glutathione (GSH), whereas M and DHEA + metformin increased GSH levels and diminished lipid peroxidation. We conclude that DHEA and metformin diminish proliferation of T cells through different pathways and that not only the increase, but also the decrease of oxidative stress inhibited proliferation of T cells, i.e. a minimal status of oxidative stress, is necessary to trigger cellular response.

Impact of DHEA(S) and cortisol on immune function in aging: a brief review

A decline in the human immune system that occurs with aging is known as immunosenescence. Several factors are involved in the process, including reduced neutrophil function and cytotoxic capacity of natural killer (NK) cells, thymus atrophy and reduced naïve T cell number, and lowered B cell antibody production in response to antigen. The endocrine system, specifically the hypothalamus–pituitary–adrenal axis, plays an important role in modulating immune function. With aging an imbalance occurs between two adrenal hormones, cortisol and DHEA, that have opposing actions on immune function. This brief review explores the interactions between cortisol and DHEA and their effects on immune function in aging, as well as potential methods to combat the endocrine-related contribution to immunosenescence, including DHEA supplementation and exercise.

Prolongation of Cardiac Allograft Survival by Inhibition of ERK1/2 Signaling in a Mouse Model

BACKGROUND

It has been demonstrated that in vitro the presence of extracellular signal-regulated kinase 1 and 2 (ERK1/2) signaling inhibitor suppresses T cell activation and Th1 development. However, pharmacological interference of ERK1/2 signaling by administration of its small molecule inhibitor has not been tested as a therapeutic target in the prevention of allograft rejection.

METHODS

The immunosuppressive effect of targeting ERK1/2 signaling was tested on cardiac allograft survival in C57BL/6 (H-2b) to Balb/c (H-2d) murine model using PD98059 inhibitor. Phosphorylation/activation of ERK 1/2 and STAT6 proteins were assessed by Western blot.

RESULTS

Blockade of ERK1/2 using PD98059 had significant immunosuppressive effect and prolonged survival of mouse cardiac allografts from 8.3+/-0.5 days (vehicle) to 12.6+/-1.3 days (100 mg/kg PD98059; P<0.0001). Combination therapy of PD98059 (100 mg/kg) with cyclosporine (CsA, 15 mg/kg for 20 days) additionally enhanced graft survival (34.4+/-1.2 days) compared to CsA (14.9+/-1.1 days; P<0.0001) or PD98059 monotherapy (P<0.0001). Attenuation of graft rejection by PD98059 correlated to reduction of intragraft ERK phosphorylation and leukocyte infiltration, and to increase in interleukin (IL)-4 or decrease in interferon-gamma production within the grafts. In vitro inhibition of ERK1/2 by PD98059 promoted Th2 differentiation by upregulation IL-4 production but not altering IL-4 stimulating STAT6 pathway.

CONCLUSION

Targeting ERK1/2 signaling results in suppression of alloimmune responses by an unique mechanism that involves Th1/Th2 skewing, suggesting a therapeutic potential of inhibition of ERK1/2 signaling for transplant rejection, particularly in combination with CsA.

Fatigue in progressive multiple sclerosis is associated with low levels of dehydroepiandrosterone

BACKGROUND AND OBJECTIVE

Fatigue is one of the most limiting symptoms in multiple sclerosis (MS) and the mechanisms underlying its origin are poorly understood. Our aim was to test whether fatigue in MS is associated with endocrine markers.

METHODS

We longitudinally studied 73 progressive MS patients. Fatigue was assessed at baseline and at 3, 6, 12 and 24 months using the Fatigue Severity Scale (FSS). Given the longitudinal design of our study, patients were labelled as sustained fatigued when FSS scores were >5.0 at all time points, and as non-fatigued when FSS scores were < or = 5.0 at all time points. Serum levels of dehydroepiandrosterone (DHEA), its sulphated conjugate (DHEAS) and cortisol were measured at each time point.

RESULTS

Twenty-nine patients scored >5.0 in the FSS at all time points, and 9 patients (12.3%) scored 5.0 at all time points. Mean baseline levels of DHEAS and DHEA were lower in MS patients with sustained fatigue when compared to patients without fatigue (P = 0.01 and P = 0.03 respectively). Analysis of DHEAS and DHEA over time showed significantly lower hormone levels in patients with fatigue [F(1,31) = 6.14, P=0.019 for DHEAS; F(1,32) = 6.63, P=0.015 for DHEA].

CONCLUSIONS

Fatigue in progressive MS could be related to low serum levels of DHEA and DHEAS. Our results suggest that these hormones should be considered as biological markers of fatigue in MS patients and that hormone replacement may thus be tested as an option to treat fatigue in MS patients.

Metformin prevents embryonic resorption induced by hyperandrogenisation with dehydroepiandrosterone in mice

The present study examined the mechanism by which metformin prevents dehydroepiandrosterone (DHEA)-induced embryonic resorption in mice. Treatment with DHEA (6 mg/100 g bodyweight, 24 and 48 h post implantation) induced 88 +/- 1 % embryonic resorption and the diminution of both serum oestradiol (E) and progesterone (P) levels. However, when metformin (50 mg/kg bodyweight) was given together with DHEA, embryo resorption (43 +/- 3% v. 35 +/- 5% in controls) and both serum E and P levels were not significantly different from controls. Glucose and insulin levels were increased in the DHEA-treated mice but when metformin was administered together with DHEA these parameters were similar to control values. Treatment with DHEA increased ovarian oxidative stress and diminished uterine nitric oxide synthase (NOS) activity; however, when metformin was administered together with DHEA, both ovarian oxidative stress and uterine NOS activity were not different from controls. Metformin treatment did not modify the percentage of CD4(+) and CD8(+) T cells from both axillar and retroperitoneal lymph nodes but prevented the increase of serum tumour necrosis factor +/- produced in DHEA-treated mice. These results show that metformin acts in DHEA-induced embryonic resorption in mice by modulating endocrine parameters, ovarian oxidative stress and uterine NOS activity.

The effects of dehydroepiandrosterone (DHEA) on in vitro spleen cell proliferation and cytokine production

Dehydroepiandrosterone (DHEA), a weak androgenic steroid, has been associated with enhancing immune responses and upregulating resistance against viral, parasitic, and bacterial infections. The objective of this study was to assess the effects of DHEA on murine spleen cell viability, proliferation, and cytokine production following in vitro stimulation with the mitogens concanavalin A (ConA) and lipopolysaccharide (LPS). Results showed that exposure to 6 microM DHEA significantly decreased the viability and proliferation of murine spleen cells stimulated with LPS, whereas no effect was seen on murine spleen cells stimulated with ConA. DHEA did influence the production of both ConA-induced and LPS-induced cytokines. DHEA also significantly reduced the mitogen-induced production of the proinflammatory cytokine interleukin-1 (IL-1) as well as the Th1 cytokines IL-2 and interferon-gamma (IFN-gamma). Increasing concentrations of DHEA significantly increased the production of the Th2 cytokine IL-10 but had no effect on the production of the Th2 cytokine IL-4, the proinflammatory cytokine tumor necrosis factor-alpha (TNF-alpha), or IL-6. These results suggest that DHEA may be an important factor for increasing Th2 cytokine production and decreasing Th1 and proinflammatory cytokine production. This study provides a more comprehensive understanding of the effects of DHEA on the rates of cell proliferation, cell viability, and cytokine production.

Dehydroepiandrosterone replacement in patients with Addison's disease has a bimodal effect on regulatory (CD4+CD25hi and CD4+FoxP3+) T cells

Oral replacement of the near-total deficiency of dehydroepiandrosterone (DHEA) in patients with Addison's disease (adrenal insufficiency) enhances mood and well-being and reduces fatigue. We studied the immunological effects of 12 wk of oral DHEA treatment in ten patients with Addison's disease receiving their normal mineralo- and glucocorticoid hormone replacement. We found that baseline circulating regulatory T cells were reduced in Addison's disease patients compared to controls, a hitherto unrecognised defect in this disorder. Oral DHEA treatment had a bimodal effect on naturally occurring regulatory (CD4+CD25hiFoxP3+) T cells and lymphocyte FoxP3 expression. Oral DHEA replacement restored normal levels of regulatory T cells and led to increased FoxP3 expression. These effects were probably responsible for a suppression of constitutive cytokine expression following DHEA withdrawal. In contrast, oral DHEA treatment led to reduced FoxP3 expression induced by TCR engagement and so augmented the cytokine response, but without a bias towards the Th1 or Th2 phenotype. NK and NKT cell numbers fell during DHEA treatment, and homeostatic lymphocyte proliferation was increased. We conclude that DHEA replacement in Addison's disease has significant immunomodulatory properties and propose that it has a greater impact on the human immune system than would be expected from its classification as a dietary supplement.

The influence of dehydroepiandrosterone on early pregnancy in mice

The aim of the present report was to study the role of high levels of dehydroepiandrosterone (DHEA) on the ovarian function and embryonic resorption during early pregnancy in BALB/c mice. Pregnant animals were injected with DHEA following both the post-implantatory (DHEA-2) and peri-implantatory (DHEA-6) models. Morphological studies of implantation sites showed 40% of embryonic resorption in the DHEA-2 group while 100% of resorption was observed in the DHEA-6 group. Serum samples of both DHEA-2 and DHEA-6 groups showed higher estradiol levels and a lower progesterone concentration than those of control groups. Ovarian prostaglandin E levels after both DHEA-2 and DHEA-6 treatments increased when compared to control groups. The antioxidant metabolite glutathione diminished during both DHEA treatments. In summary, the data presented here suggest that DHEA treatment during early pregnancy modulates the ovarian function and is responsible for embryonic resorption with different degrees depending on when it is administered.

Severity of murine collagen-induced arthritis correlates with increased CYP7B activity: enhancement of dehydroepiandrosterone metabolism by interleukin-1beta

OBJECTIVE

The endogenous steroid dehydroepiandrosterone (DHEA) has been reported to play a role in rheumatoid arthritis (RA). DHEA is metabolized by the P450 enzyme CYP7B into 7alpha-OH-DHEA, which has immunostimulating properties. This study was undertaken to investigate the putative role of CYP7B in arthritis using murine collagen-induced arthritis (CIA), an interleukin-1beta (IL-1beta)-dependent model.

METHODS

DBA/1J mice were immunized and administered a booster with type II collagen. The presence of 7alpha-OH-DHEA was determined in both arthritic and nonarthritic joints and the serum of CIA mice by radioimmunoassay. CYP7B messenger RNA (mRNA) expression was analyzed in synovial biopsy samples, and in fibroblast-like synoviocytes (FLS) isolated from these synovial biopsy samples, by reverse transcriptase-polymerase chain reaction (RT-PCR). In addition, the regulatory role of IL-1beta on CYP7B activity in FLS was determined using RT-PCR, Western blotting, and high-performance liquid chromatography.

RESULTS

In knee joint synovial biopsy samples from arthritic mice, 7alpha-OH-DHEA levels were 5-fold higher than in nonarthritic mice. Elevated levels of 7alpha-OH-DHEA were accompanied by an increase in CYP7B mRNA expression and were positively correlated with disease severity. In serum, no differences in 7alpha-OH-DHEA levels were observed between arthritic and nonarthritic mice. Incubation of FLS with IL-1beta resulted in a dose-dependent increase in 7alpha-OH-DHEA formation. In addition, IL-1beta enhanced CYP7B mRNA and CYP7B protein levels in FLS.

CONCLUSION

Disease progression in CIA is correlated with enhanced CYP7B activity, which leads to locally enhanced 7alpha-OH-DHEA levels. Elevated IL-1beta levels within the arthritic joint may regulate this increase in CYP7B activity.

Serum concentrations of dehydroepiandrosterone and dehydroepiandrosterone sulfate and their relation to cytokine production during and after normal pregnancy

BACKGROUND

Since dehydroepiandrosterone (DHEA) and dehydroepiandrosterone sulfate (DHEAS) have been suggested to have immunoregulatory effects, changes in the levels of these substances during and after pregnancy might affect the maternal immune system. We examined serum concentrations of DHEA and DHEAS, and cytokine production during pregnancy and after delivery.

METHODS

The subjects were 73 normal pregnant, 76 normal postpartum and 30 normal non-pregnant women. Whole-blood was stimulated with phorbol 12-myristate 13-acetate (PMA) and ionomycin and the levels of cytokines in the supernatant were measured using enzyme-linked immunosorbent assay (ELISA). DHEA and DHEAS were measured using ELISA and gas chromatography-mass spectrometry (GC-MS), respectively.

RESULTS

The serum DHEA levels increased in the first and in the second trimesters and decreased after delivery until 11 months postpartum. DHEAS levels were decreased in the second and in the third trimesters and returned to non-pregnant levels after pregnancy. All measured cytokines (IFN-gamma, IL-2, IL-4 and IL-10) were decreased during pregnancy and subsequently increased postpartum. We found significant negative correlations between DHEA and cytokine levels.

CONCLUSIONS

Increase of serum DHEA in the first and the second trimesters may suppress immune reaction during pregnancy, while a decrease of DHEA after delivery may induce postpartum enhancement of the maternal immune system. DHEA may be involved in modifying the maternal immune responses during and after pregnancy.

16alpha-Bromo-epiandrosterone therapy modulates experimental feline immunodeficiency virus viremia: initial enhancement leading to long-term suppression

16alpha-Bromo-epiandrosterone (epiBr), a synthetic derivative of the natural hormone dehyroepiandrosterone (DHEA), was evaluated for its effects on feline immunodeficiency virus (FIV) infection in experimental cats. The rationale for this study was based on the ability of DHEA to significantly reduce the mortality to viral infections in mice. DHEA and epiBr also have demonstrable in vitro anti-viral activity for both HIV-1 and FIV. Preliminary pharmacokinetic studies in cats demonstrated that subcutaneously injected epiBr was rapidly absorbed, completely metabolized, and nontoxic. Metabolites were excreted in both urine and feces, with the latter having the most complex pattern of breakdown products. Cats were then divided into four groups; two groups were infected with FIV and two uninfected. Two groups, one infected and one uninfected were treated on 5 consecutive days of weeks 0, 4, 8, 12 and 16 with epiBr. The remaining two groups were mock treated with the drug vehicle alone. Treatment started 1 week prior to infection and extended for 4 weeks after infection. Cats were observed for 20 weeks post-FIV infection. Infected cats had identical decreases in blood neutrophil and lymphocyte counts following, regardless of whether they were treated with epiBr or vehicle alone. The CD4/CD8 T-cell ratio was decreased following FIV exposure, but was significantly more decreased for the epiBr treated animals from week 2 post-infection onward. CD4+ T cells were decreased in FIV-infected cats treated with epiBr compared to their untreated cohort, while CD8+ T cells tended to be higher in treated animals. FIV infected cats that were treated with epiBr had over one-log higher virus loads at week 2 post-infection than non-epiBr treated cohorts. In spite of this enhanced initial viremia, the subsequent levels of virus in the blood were significantly lower in epiBr treated versus untreated animals. EpiBr treated cats had significantly higher FIV-p24 antibody responses than control cats receiving vehicle alone, although primary and secondary antibody responses to a T-cell dependent non-FIV antigen, keyhole limpet hemocyanin (KLH), were unaffected. EpiBr treatment significantly decreased the expected FIV-induced suppression of IL-12 p40 mRNA levels in peripheral blood mononuclear cells (PBMCs) observed at weeks 4, 5, 8, 9 and 16 post-infection, but had no influence on FIV-induced changes in IL-4, IL-6, IL-10, IFN-gamma, MIP-1alpha and RANTES.

Administration of dehydroepiandrosterone suppresses experimental allergic encephalomyelitis in SJL/J mice

Experimental allergic encephalomyelitis (EAE) is a Th1-mediated inflammatory demyelinating disease in the CNS, an animal model of multiple sclerosis. We have examined the effect of dehydroepiandrosterone (DHEA) on the development of EAE in mice. The addition of DHEA to cultures of myelin basic protein-primed splenocytes resulted in a significant decrease in T cell proliferation and secretion of (pro)inflammatory cytokines (IFN-gamma, IL-12 p40, and TNF-alpha) and NO in response to myelin basic protein. These effects were associated with a decrease in activation and translocation of NF-kappaB. In vivo administration of DHEA significantly reduced the severity and incidence of acute EAE, along with a decrease in demyelination/inflammation and expressions of (pro)inflammatory cytokines in the CNS. These studies suggest that DHEA has potent anti-inflammatory properties, which at least are in part mediated by its inhibition of NF-kappaB activation.