11β-Hydroxysteroid dehydrogenase-1 is a novel regulator of skin homeostasis and a candidate target for promoting tissue repair

Electrospun 11β-HSD1 Inhibitor-Loaded Scaffolds for Accelerating Diabetic Ulcer Healing

Diabetic ulcers (DUs) are a common and severe complication of diabetes, characterized by impaired wound healing due to a complex pathophysiological mechanism. Elevated levels of 11β-hydroxysteroid dehydrogenase type I (11β-HSD1) in wounds have been demonstrated to modulate glucocorticoid activity, leading to delayed skin cell proliferation and restricted angiogenesis, ultimately hindering wound healing. In this study, we propose an electrospun poly(ε-caprolactone) (PCL) nanofiber scaffold doped with the 11β-HSD1 inhibitor BVT2733 (BPs) to prevent 11β-HSD1 activity during the diabetic wound healing process. The electrospun scaffold loaded with BVT2733 is designed to achieve localized inhibition of 11β-HSD1 in DUs. This scaffold exhibited a porous morphology and desirable drug-loading capacity, meeting the requirements for wound coverage and effective delivery of BVT2733 BPs. In vitro studies demonstrated that the sustained release of BVT2733 from the scaffold promoted skin cell proliferation and migration while stimulating angiogenesis by upregulating HIF1-α/VEGF expression. The therapeutic effect of the scaffold was further confirmed in a full-thickness wound model using diabetic mice. The mice treated with the scaffolds exhibited an accelerated wound healing rate, increased neovascularization, enhanced collagen deposition, and regeneration of skin appendages within 2 weeks postinjury. The findings here provide evidence for the use of 11β-HSD1 inhibitor-integrated biomaterials in treating DUs and represent a novel biological platform for modulating dysregulated mechanisms in DUs.

Role of corticosteroids in skin physiology and therapeutic potential of an 11β-HSD1 inhibitor: A review

Skin is a major site of cortisol bioconversion by 11β-hydroxysteroid dehydrogenase type 1 (11β-HSD1) enzymes which catalyze intracellular inactive cortisone into physiologically active cortisol. 11β-HSD1 is highly expressed in skin, especially in dermal fibroblasts, epidermal keratinocytes, melanocytes, and hair follicles, and plays important roles in regulating keratinocytes, fibroblast proliferation, and has roles in skin aging. Inhibition of 11β-HSD1 may reverse decreased collagen levels observed in extrinsically and intrinsically aged skin. Inhibitors of 11β-HSD1 may also have the potential to reverse decreased collagen observed in skin atrophy induced by glucocorticoid treatment. This systematic review aimed to summarize the current knowledge of roles for 11β-HSD1 inhibitor in skin physiology and potential for future use in medications. Studies have demonstrated that immediately following experimental insult in an animal model, there is increased expression of 11β-HSD1, and that topical application of an 11β-HSD1 inhibitor increases the rate of healing, increases skin collagen content, increases dermal fibroblasts, and increases dermal thickness. Furthermore, in patients with type 2 diabetes mellitus, 11β-HSD1 inhibitors reduce wound diameter after injury. Further development of 11β-HSD1 inhibitors appears to be a promising area for treating aging skin, aiding wound healing, and mitigating effects of systemic glucocorticoid use. Both topically and orally administered 11β-HSD1 inhibitors appear to be viable avenues for future research.

Hyperglycemia-activated 11β-hydroxysteroid dehydrogenase type 1 increases endoplasmic reticulum stress and skin barrier dysfunction

The diabetes mellitus (DM) skin shows skin barrier dysfunction and skin lipid abnormality, similar to conditions induced by systemic or local glucocorticoid excess and aged skin. Inactive glucocorticoid (GC) is converted into active glucocorticoid by 11β-hydroxysteroid dehydrogenase type 1 (11β-HSD1). Hyperglycemia in DM and excessive GC are known to increase endoplasmic reticulum (ER) stress. We hypothesized that hyperglycemia affects systemic GC homeostasis and that the action of skin 11β-HSD1 and GC contributes to increased ER stress and barrier defects in DM. We compared 11β-HSD1, active GC, and ER stress between hyperglycemic and normoglycemic conditions in normal human keratinocytes and db/db mice. 11β-HSD1 and cortisol increased with time in keratinocyte culture under hyperglycemic conditions. 11β-HSD1 siRNA-transfected cells did not induce cortisol elevation in hyperglycemic condition. The production of 11β-HSD1 and cortisol was suppressed in cell culture treated with an ER stress-inhibitor. The 14-week-old db/db mice showed higher stratum corneum (SC) corticosterone, and skin 11β-HSD1 levels than 8-week-old db/db mice. Topical 11β-HSD1 inhibitor application in db/db mice decreased SC corticosterone levels and improved skin barrier function. Hyperglycemia in DM may affect systemic GC homeostasis, activate skin 11β-HSD1, and induce local GC excess, which increases ER stress and adversely affects skin barrier function.

Fractional ablative laser therapy for the treatment of severe burn scars: A pilot study of the underlying mechanisms

Ablative fractional resurfacing is clinically an efficient treatment for burn scar management. The aim of this pilot study was to investigate the poorly understood mechanisms underlying ablative fractional CO2 laser (AFL-CO2) therapy in relation to biomarkers S100 and 11β-hydroxysteroid dehydrogenase type 1 (11β-HSD1). S100 stains for Langerhans cells and neuronal cells, potentially representing the pruritus experienced. 11β-HSD1 catalyses the interconversion of cortisol and cortisone in cells, promoting tissue remodelling. Immunohistochemical analysis of S100 and 11β-HSD1 protein expression in the dermis and epidermis of the skin was performed on normal skin, before and after AFL-CO2 therapy. Data assessing outcome parameters was collected concurrently with the skin biopsies. 13 patients were treated with AFL-CO2 therapy. Langerhans cells decreased by 39% after 2nd treatment. Neuronal cells were overexpressed before treatment in the scar tissue by 91% but levels returned to that resembling normal skin. 11β-HSD1 expression in keratinocytes was significantly higher after laser treatment compared to before in scar tissue (p <0.01). No clear correlation was found in dermal fibroblast numbers throughout the treatment course. Whilst the role of the explored mechanisms and their association with clinical outcomes cannot conclusively be stated, this pilot study demonstrates promising trends that encourages investigation into this relationship.

In vitro methods to assess 11β-hydroxysteroid dehydrogenase type 1 activity

11β-Hydroxysteroid dehydrogenase type 1 (11β-HSD1) converts inactive 11-keto-glucocorticoids to their active 11β-hydroxylated forms. It also catalyzes the oxoreduction of other endogenous and exogenous substrates. The ubiquitously expressed 11β-HSD1 shows high levels in liver and other metabolically active tissues such as brain and adipose tissue. Pharmacological inhibition of 11β-HSD1 was found to ameliorate adverse metabolic effects of elevated glucocorticoids in rodents and humans, improve wound healing and delay skin aging, and enhance memory and cognition in rodent Alzheimer's disease models. Thus, there is an interest to develop 11β-HSD1 inhibitors for therapeutic purposes. This chapter describes in vitro methods to assess 11β-HSD1 enzyme activity for different purposes, be it in disease models, for the assessment of the kinetics of novel substrates or for the screening and characterization of inhibitors. 11β-HSD1 protein expression and preparations of the different biological samples are discussed first, followed by a description of a well-established and easily adaptable 11β-HSD1 enzyme activity assay. Finally, different readout methods are shortly described. This chapter should provide the reader with a toolbox of methods to assess 11β-HSD1 activity with instructions in the form of a decision tree for the choice and implementation of an appropriate enzyme activity assay.

11β-HSD1 inhibition does not affect murine tumour angiogenesis but may exert a selective effect on tumour growth by modulating inflammation and fibrosis

Glucocorticoids inhibit angiogenesis by activating the glucocorticoid receptor. Inhibition of the glucocorticoid-activating enzyme 11β-hydroxysteroid dehydrogenase type 1 (11β-HSD1) reduces tissue-specific glucocorticoid action and promotes angiogenesis in murine models of myocardial infarction. Angiogenesis is important in the growth of some solid tumours. This study used murine models of squamous cell carcinoma (SCC) and pancreatic ductal adenocarcinoma (PDAC) to test the hypothesis that 11β-HSD1 inhibition promotes angiogenesis and subsequent tumour growth. SCC or PDAC cells were injected into female FVB/N or C57BL6/J mice fed either standard diet, or diet containing the 11β-HSD1 inhibitor UE2316. SCC tumours grew more rapidly in UE2316-treated mice, reaching a larger (P<0.01) final volume (0.158 ± 0.037 cm3) than in control mice (0.051 ± 0.007 cm3). However, PDAC tumour growth was unaffected. Immunofluorescent analysis of SCC tumours did not show differences in vessel density (CD31/alpha-smooth muscle actin) or cell proliferation (Ki67) after 11β-HSD1 inhibition, and immunohistochemistry of SCC tumours did not show changes in inflammatory cell (CD3- or F4/80-positive) infiltration. In culture, the growth/viability (assessed by live cell imaging) of SCC cells was not affected by UE2316 or corticosterone. Second Harmonic Generation microscopy showed that UE2316 reduced Type I collagen (P<0.001), whilst RNA-sequencing revealed that multiple factors involved in the innate immune/inflammatory response were reduced in UE2316-treated SCC tumours. 11β-HSD1 inhibition increases SCC tumour growth, likely via suppression of inflammatory/immune cell signalling and extracellular matrix deposition, but does not promote tumour angiogenesis or growth of all solid tumours.

Skin 11β-hydroxysteroid dehydrogenase type 1 enzyme expression regulates burn wound healing and can be targeted to modify scar characteristics

BACKGROUND

Excessive scarring and fibrosis are the most severe and common complications of burn injury. Prolonged exposure to high levels of glucocorticoids detrimentally impacts on skin, leading to skin thinning and impaired wound healing. Skin can generate active glucocorticoids locally through expression and activity of the 11β-hydroxysteroid dehydrogenase type 1 enzyme (11β-HSD1). We hypothesised that burn injury would induce 11β-HSD1 expression and local glucocorticoid metabolism, which would have important impacts on wound healing, fibrosis and scarring. We additionally proposed that pharmacological manipulation of this system could improve aspects of post-burn scarring.

METHODS

Skin 11β-HSD1 expression in burns patients and mice was examined. The impacts of 11β-HSD1 mediating glucocorticoid metabolism on burn wound healing, scar formation and scar elasticity and quality were additionally examined using a murine 11β-HSD1 genetic knockout model. Slow-release scaffolds containing therapeutic agents, including active and inactive glucocorticoids, were developed and pre-clinically tested in mice with burn injury.

RESULTS

We demonstrate that 11β-HSD1 expression levels increased substantially in both human and mouse skin after burn injury. 11β-HSD1 knockout mice experienced faster wound healing than wild type mice but the healed wounds manifested significantly more collagen deposition, tensile strength and stiffness, features characteristic of excessive scarring. Application of slow-release prednisone, an inactive glucocorticoid, slowed the initial rate of wound closure but significantly reduced post-burn scarring via reductions in inflammation, myofibroblast generation, collagen production and scar stiffness.

CONCLUSIONS

Skin 11β-HSD1 expression is a key regulator of wound healing and scarring after burn injury. Application of an inactive glucocorticoid capable of activation by local 11β-HSD1 in skin slows the initial rate of wound closure but significantlyimproves scar characteristics post burn injury.

Comparison of in vitro scratch wound assay experimental procedures

Fibroblast migration is an important aspect of wound healing. Different factors can influence migration and as such proper wound healing. In vitro scratch wound assays are used to examine cellular migration. However, the wide array of techniques available reduces reproducibility of findings. In this paper, we compare two techniques for wound creation; i.e. the exclusion method or scratching of cell monolayers. Furthermore, we investigate if analysis software influences experimental outcome by comparing both commercially and freely available analysis software. Besides, we examine the effect of cortisol on migration behavior of fibroblasts and identify possible caveats in experimental design. Results show a significantly reduced migration of fibroblasts when wounds are created using a cell exclusion method. Furthermore, addition of cortisol to the cell culture media only reduced migration of fibroblast monolayers that had been scratched but not in those where wounds were created using the exclusion method. A possible explanation related to cytokine expression is discussed.

p16INK4a Plays Critical Role in Exacerbating Inflammaging in High Fat Diet Induced Skin

BACKGROUND

Long term high fat diets (HFD) promote skin aging pathogenesis, but detailed mechanisms remain unclear especially for inflammaging, which has recently emerged as a pathway correlating aging and age-related disease with inflammation. p16INK4a (hereafter termed p16) inhibits the cell cycle, with p16 deletion significantly inhibiting inflammaging. We observed that HFD-induced p16 overexpression in the skin. Therefore, we investigated if p16 exacerbated inflammaging in HFD-induced skin and also if p16 deletion exerted protective effects against this process.

METHODS

Eight-week-old double knockout (KO) ApoE-/-p16-/- mice and ApoE-/- littermates were fed HFD for 12 weeks and their skin phenotypes were analyzed. We measured skin fibrosis, senescence-associated secretory phenotype (SASP) levels, and integrin-inflammasome pathway activation using histopathological, RNA-sequencing (RNA-seq), bioinformatics analysis, and molecular techniques.

RESULTS

We found that HFD contributed to inflammaging in the skin by activating the NLRP3 inflammasome pathway, increasing inflammatory infiltration, and promoting apoptosis by balancing expression between proapoptotic and antiapoptotic molecules. p16 knockout, when compared with the ApoE-/- phenotype, inhibited skin fibrosis by ameliorating inflammatory infiltration and proinflammatory factor expression (Interleukin-1β (IL-1β), Interleukin-6 (IL-6), and tumor necrosis factor-α (TNF-α)), and also alleviated inflammaging skin progress induced by HFD in the ApoE-/- mouse model. RNA-seq showed that p16 KO mice inhibited both integrin-inflammasome and NF-κB proinflammatory pathway activation.

CONCLUSIONS

p16 deletion or p16 positive cell clearance could be a novel strategy preventing long term HFD-induced skin aging.

Wound Healing Impairment in Type 2 Diabetes Model of Leptin-Deficient Mice—A Mechanistic Systematic Review

Type II diabetes mellitus (T2DM) is one of the most prevalent diseases in the world, associated with diabetic foot ulcers and impaired wound healing. There is an ongoing need for interventions effective in treating these two problems. Pre-clinical studies in this field rely on adequate animal models. However, producing such a model is near-impossible given the complex and multifactorial pathogenesis of T2DM. A leptin-deficient murine model was developed in 1959 and relies on either dysfunctional leptin (ob/ob) or a leptin receptor (db/db). Though monogenic, this model has been used in hundreds of studies, including diabetic wound healing research. In this study, we systematically summarize data from over one hundred studies, which described the mechanisms underlying wound healing impairment in this model. We briefly review the wound healing dynamics, growth factors’ dysregulation, angiogenesis, inflammation, the function of leptin and insulin, the role of advanced glycation end-products, extracellular matrix abnormalities, stem cells’ dysregulation, and the role of non-coding RNAs. Some studies investigated novel chronic diabetes wound models, based on a leptin-deficient murine model, which was also described. We also discussed the interventions studied in vivo, which passed into human clinical trials. It is our hope that this review will help plan future research.

Oral 11β-HSD1 inhibitor AZD4017 improves wound healing and skin integrity in adults with type 2 diabetes mellitus: a pilot randomized controlled trial

BACKGROUND

Chronic wounds (e.g. diabetic foot ulcers) reduce the quality of life, yet treatments remain limited. Glucocorticoids (activated by the enzyme 11β-hydroxysteroid dehydrogenase type 1, 11β-HSD1) impair wound healing.

OBJECTIVES

Efficacy, safety, and feasibility of 11β-HSD1 inhibition for skin function and wound healing.

DESIGN

Investigator-initiated, double-blind, randomized, placebo-controlled, parallel-group phase 2b pilot trial.

METHODS

Single-center secondary care setting. Adults with type 2 diabetes mellitus without foot ulcers were administered 400 mg oral 11β-HSD1 inhibitor AZD4017 (n = 14) or placebo (n = 14) bi-daily for 35 days. Participants underwent 3-mm full-thickness punch skin biopsies at baseline and on day 28; wound healing was monitored after 2 and 7 days. Computer-generated 1:1 randomization was pharmacy-administered. Analysis was descriptive and focused on CI estimation. Of the 36 participants screened, 28 were randomized.

RESULTS

Exploratory proof-of-concept efficacy analysis suggested AZD4017 did not inhibit 24-h ex vivoskin 11β-HSD1 activity (primary outcome; difference in percentage conversion per 24 h 1.1% (90% CI: -3.4 to 5.5) but reduced systemic 11β-HSD1 activity by 87% (69-104%). Wound diameter was 34% (7-63%) smaller with AZD4017 at day 2, and 48% (12-85%) smaller after repeat wounding at day 30. AZD4017 improved epidermal integrity but modestly impaired barrier function. Minimal adverse events were comparable to placebo. Recruitment rate, retention, and data completeness were 2.9/month, 27/28, and 95.3%, respectively.

CONCLUSION

A phase 2 trial is feasible, and preliminary proof-of-concept data suggests AZD4017 warrants further investigation in conditions of delayed healing, for example in diabetic foot ulcers.

SIGNIFICANCE STATEMENT

Stress hormone activation by the enzyme 11β-HSD type 1 impairs skin function (e.g. integrity) and delays wound healing in animal models of diabetes, but effects in human skin were previously unknown. Skin function was evaluated in response to treatment with a 11β-HSD type 1 inhibitor (AZD4017), or placebo, in people with type 2 diabetes. Importantly, AZD4017 was safe and well tolerated. This first-in-human randomized, controlled, clinical trial found novel evidence that 11β-HSD type 1 regulates skin function in humans, including improved wound healing, epidermal integrity, and increased water loss. Results warrant further studies in conditions of impaired wound healing, for example, diabetic foot ulcers to evaluate 11β-HSD type 1 as a novel therapeutic target forchronic wounds.

Spaceflight Stressors and Skin Health

Traveling to space puts astronauts at risk of developing serious health problems. Of particular interest is the skin, which is vitally important in protecting the body from harmful environmental factors. Although data obtained from long-duration spaceflight studies are inconsistent, there have been indications of increased skin sensitivity and signs of dermal atrophy in astronauts. To better understand the effects of spaceflight stressors including microgravity, ionizing radiation and psychological stress on the skin, researchers have turned to in vitro and in vivo simulation models mimicking certain aspects of the spaceflight environment. In this review, we provide an overview of these simulation models and highlight studies that have improved our understanding on the effect of simulation spaceflight stressors on skin function. Data show that all aforementioned spaceflight stressors can affect skin health. Nevertheless, there remains a knowledge gap regarding how different spaceflight stressors in combination may interact and affect skin health. In future, efforts should be made to better simulate the spaceflight environment and reduce uncertainties related to long-duration spaceflight health effects.

A novel mineralocorticoid receptor antagonist, 7,3',4'-trihydroxyisoflavone improves skin barrier function impaired by endogenous or exogenous glucocorticoids

Excess glucocorticoids (GCs) with either endogenous or exogenous origins deteriorate skin barrier function. GCs bind to mineralocorticoid and GC receptors (MRs and GRs) in normal human epidermal keratinocytes (NHEKs). Inappropriate MR activation by GCs mediates various GC-induced cutaneous adverse events. We examined whether MR antagonists can ameliorate GC-mediated skin barrier dysfunction in NHEKs, reconstructed human epidermis (RHE), and subjects under psychological stress (PS). In a preliminary clinical investigation, topical MR antagonists improved skin barrier function in topical GC-treated subjects. In NHEKs, cortisol induced nuclear translocation of GR and MR, and GR and MR antagonists inhibited cortisol-induced reductions of keratinocyte differentiation. We identified 7,3',4'-trihydroxyisoflavone (7,3',4'-THIF) as a novel compound that inhibits MR transcriptional activity by screening 30 cosmetic compounds. 7,3',4'-THIF ameliorated the cortisol effect which decreases keratinocyte differentiation in NHEKs and RHE. In a clinical study on PS subjects, 7,3',4'-THIF (0.1%)-containing cream improved skin barrier function, including skin surface pH, barrier recovery rate, and stratum corneum lipids. In conclusion, skin barrier dysfunction owing to excess GC is mediated by MR and GR; thus, it could be prevented by treatment with MR antagonists. Therefore, topical MR antagonists are a promising therapeutic option for skin barrier dysfunction after topical GC treatment or PS.

Increased Expression of 11β-Hydroxysteroid Dehydrogenase Type 1 Contributes to Epidermal Permeability Barrier Dysfunction in Aged Skin

Inactive cortisone is converted into active cortisol by 11β-hydroxysteroid dehydrogenase type 1 (11β-HSD1). Excessive levels of active glucocorticoids could deteriorate skin barrier function; barrier impairment is also observed in aged skin. In this study, we aimed to determine whether permeability barrier impairment in the aged skin could be related to increased 11β-HSD1 expression. Aged humans (n = 10) showed increased cortisol in the stratum corneum (SC) and oral epithelium, compared to young subjects (n = 10). 11β-HSD1 expression (as assessed via immunohistochemical staining) was higher in the aged murine skin. Aged hairless mice (56-week-old, n = 5) manifested greater transepidermal water loss, lower SC hydration, and higher levels of serum inflammatory cytokines than the young mice (8-week-old, n = 5). Aged 11β-HSD1 knockout mice (n = 11), 11β-HSD1 inhibitor (INHI)-treated aged wild type (WT) mice (n = 5) and young WT mice (n = 10) exhibited reduced SC corticosterone level. Corneodesmosome density was low in WT aged mice (n = 5), but high in aged 11β-HSD1 knockout and aged INHI-treated WT mice. Aged mice exhibited lower SC lipid levels; this effect was reversed by INHI treatment. Therefore, upregulation of 11β-HSD1 in the aged skin increases the active-glucocorticoid levels; this suppresses SC lipid biosynthesis, leading to impaired epidermal permeability barrier.

A randomised controlled pilot trial of oral 11β-HSD1 inhibitor AZD4017 for wound healing in adults with type 2 diabetes mellitus.. [DOI: 10.1101/2021.03.23.21254200] [Citation(s) in RCA: 0] [Impact Index Per Article: 0]

Chronic wounds (e.g. diabetic foot ulcers) have a major impact on quality of life, yet treatments remain limited. Glucocorticoids impair wound healing; preclinical research suggests that blocking glucocorticoid activation by the enzyme 11β-hydroxysteroid dehydrogenase type 1 (11β-HSD1) improves wound repair. This investigator-initiated double-blind, randomised, placebo-controlled parallel-group phase 2b pilot trial investigated efficacy, safety and feasibility of 11β-HSD1 inhibition for 35 days by oral AZD4017 (AZD) treatment in adults with type 2 diabetes (n=14) compared to placebo (PCB, n=14) in a single-centre secondary care setting. Computer-generated 1:1 randomisation was pharmacy-administered. From 300 screening invitations, 36 attended, 28 were randomised. There was no proof-of-concept that AZD inhibited 24 hour skin 11β-HSD1 activity at day 28 (primary outcome: adjusted difference AZD-PCB 90% CI (diffCI)=-3.4,5.5) but systemic 11β-HSD1 activity (median urinary [THF+alloTHF]/THE ratio) was 87% lower with AZD at day 35 (PCB 1.00, AZD 0.13, diffCI=-1.04,-0.69). Mean wound gap diameter (mm) following baseline 2mm punch biopsy was 34% smaller at day 2 (PCB 1.51, AZD 0.98, diffCI=-0.95,-0.10) and 48% smaller after repeat wounding at day 30 (PCB 1.35, AZD 0.70, diffCI=-1.15,-0.16); results also suggested greater epidermal integrity but modestly impaired barrier function with AZD. AZD was well-tolerated with minimal side effects and comparable adverse events between treatments. Staff availability restricted recruitment (2.9/month); retention (27/28) and data completeness (95.3%) were excellent. These preliminary findings suggest that AZD may improve wound healing in patients with type 2 diabetes and warrant a fully-powered trial in patients with active ulcers. [Trial Registry: www.isrctn.com/ISRCTN74621291.

Funding

MRC Confidence in Concept and NIHR Senior Investigator Award.]

Single Sentence Summary

AZD4017 was safe; data suggested improved skin healing / integrity, and modestly reduced epidermal barrier function in patients with type 2 diabetes.

Disclosure Summary

I certify that neither I nor my co-authors have a conflict of interest as described above that is relevant to the subject matter or materials included in this Work.

Antifungal therapy with azoles and the syndrome of acquired mineralocorticoid excess

The syndromes of mineralocorticoid excess describe a heterogeneous group of clinical manifestations leading to endocrine hypertension, typically either through direct activation of mineralocorticoid receptors or indirectly by impaired pre-receptor enzymatic regulation or through disturbed renal sodium homeostasis. The phenotypes of these disorders can be caused by inherited gene variants and somatic mutations or may be acquired upon exposures to exogenous substances. Regarding the latter, the symptoms of an acquired mineralocorticoid excess have been reported during treatment with azole antifungal drugs. The current review describes the occurrence of mineralocorticoid excess particularly during the therapy with posaconazole and itraconazole, addresses the underlying mechanisms as well as inter- and intra-individual differences, and proposes a therapeutic drug monitoring strategy for these two azole antifungals. Moreover, other therapeutically used azole antifungals and ongoing efforts to avoid adverse mineralocorticoid effects of azole compounds are shortly discussed.

Inhibitors of 11β-Hydroxysteroid Dehydrogenase Type 1 as Potential Drugs for Type 2 Diabetes Mellitus—A Systematic Review of Clinical and In Vivo Preclinical Studies

Diabetes mellitus is a pathology with increasing frequency in society, being one of the main causes of death worldwide. For this reason, new therapeutic targets have been studied over the years. 11β-hydroxysteroid dehydrogenase type 1 (11β-HSD1) is an enzyme responsible for reducing cortisone to its active form cortisol, which can lead to metabolic changes such as insulin resistance and hyperglycemia. Therefore, 11β-HSD1 inhibition may offer a new therapeutic approach for type 2 diabetes mellitus. This work intends to systematically review the available scientific evidence on this subject. For this, a search was conducted in three databases and 15 clinical and in vivo preclinical studies were included in this review. Despite the high inhibitory and selectivity levels achieved with several molecules and the demonstrated clinical efficacy in diabetes treatment, no phase III clinical trials have yet been conducted. This is important because the long-term effects of 11β-HSD1 inhibitors including the consequences in hypothalamic–pituitary–adrenal axis must be evaluated. However, this enzyme remains a promising target for drug development, including due to its effectiveness in controlling various factors that constitute the metabolic syndrome and its potential for multiple indications in patients with diabetes, including wound healing and weight loss.

Inhibition of 11β-HSD1 Expression by Insulin in Skin: Impact for Diabetic Wound Healing

Chronic, non-healing wounds impose a great burden on patients, professionals and health care systems worldwide. Diabetes mellitus (DM) and obesity are globally highly prevalent metabolic disorders and increase the risk for developing chronic wounds. Glucocorticoids (GCs) are endogenous stress hormones that exert profound effects on inflammation and repair systems. 11-beta-hydroxysteroid dehydrogenase 1 (11β-HSD1) is the key enzyme which controls local GC availability in target tissues such as skin. Since treatment with GCs has detrimental side effects on skin integrity, causing atrophy and delayed wound healing, we asked whether the dysregulated expression of 11β-HSD1 and consequently local GC levels in skin contribute to delayed wound healing in obese, diabetic db/db mice. We found increased expression of 11β-HSD1 during disturbed wound healing and in the healthy skin of obese, diabetic db/db mice. Cell analysis revealed increased expression of 11β-HSD1 in fibroblasts, myeloid cells and dermal white adipose tissue from db/db mice, while expression in keratinocytes was unaffected. Among diabetes- and obesity-related factors, insulin and insulin-like growth factor 1 down-regulated 11β-HSD1 expression in fibroblasts and myeloid cells, while glucose, fatty acids, TNF-α and IL-1β did not affect it. Insulin exerted its inhibitory effect on 11β-HSD1 expression by activating PI3-kinase/Akt-signalling. Consequently, the inhibitory effect of insulin is attenuated in fibroblasts from insulin-resistant db/db mice. We conclude that insulin resistance in obesity and diabetes prevents the down-regulation of 11β-HSD1, leading to elevated endogenous GC levels in diabetic skin, which could contribute to impaired wound healing in patients with DM.

Cortisol Metabolism in Carp Macrophages: A Role for Macrophage-Derived Cortisol in M1/M2 Polarization

Macrophages are crucial not only for initiation of inflammation and pathogen eradication (classically polarized M1 macrophages), but also for inflammation inhibition and tissue regeneration (alternatively polarized M2 macrophages). Their polarization toward the M1 population occurs under the influence of interferon-γ + lipopolysaccharide (IFN-γ + LPS), while alternatively polarized M2 macrophages evolve upon, e.g., interlukin 4 (IL-4) or cortisol stimulation. This in vitro study focused on a possible role for macrophage-derived cortisol in M1/M2 polarization in common carp. We studied the expression of molecules involved in cortisol synthesis/conversion from and to cortisone like 11β-hydroxysteroid dehydrogenase type 2 and 3. (11β-HSD2 and 3) and 11β-hydroxylase (CYP11b), as well as the expression of glucocorticoid receptors (GRs) and proliferator-activated receptor gamma (PPARγ) in M1 and M2 macrophages. Lastly, we analyzed how inhibition of these molecules affect macrophage polarization. In M1 cells, upregulation of gene expression of GRs and 11β-HSD3 was found, while, in M2 macrophages, expression of 11β-hsd2 was upregulated. Moreover, blocking of cortisol synthesis/conversion and GRs or PPARγ induced changes in expression of anti-inflammatory interleukin 10 (IL-10). Consequently, our data show that carp monocytes/macrophages can convert cortisol. The results strongly suggest that cortisol, via intracrine interaction with GRs, is important for IL-10-dependent control of the activity of macrophages and for the regulation of M1/M2 polarization to finally determine the outcome of an infection.

Role of 11β-hydroxysteroid dehydrogenase type 1 in the development of atopic dermatitis

Glucocorticoids (GCs) are potent anti-inflammatory drugs, the secretion of which is mediated and controlled by the hypothalamic–pituitary–adrenal axis. However, they are also secreted de novo by peripheral tissues for local use. Several tissues express 11β-hydroxysteroid dehydrogenase 1 (11β-HSD1), including the skin. The inactive GC cortisone is converted by 11β-HSD1 to active GC cortisol, which is responsible for delayed wound healing during a systemic excess of GC. However, the role of 11β-HSD1 in inflammation is unclear. We assessed whether 11β-HSD1 affects the development of atopic dermatitis (AD) in vitro and in vivo. The expression of 11β-HSD1 in the epidermis of AD lesions was higher than that in the epidermis of healthy controls. Knockdown of 11β-HSD1 in human epidermal keratinocytes increased the production of thymic stromal lymphopoietin. In an oxazolone-induced mouse model of AD, localized inhibition of 11β-HSD1 aggravated the development of AD and increased serum cytokine levels associated with AD. Mice with whole-body knockout (KO) of 11β-HSD1 developed significantly worse AD upon induction by oxazolone. We propose that 11β-HSD1 is a major factor affecting AD pathophysiology via suppression of atopic inflammation due to the modulation of active GC in the skin.

TLR3 augments glucocorticoid-synthetic enzymes expression in epidermal keratinocytes; Implications of glucocorticoid metabolism in rosacea epidermis

BACKGROUND

While most skin diseases benefit from topical steroids, rosacea symptoms are exacerbated by topical steroids. In the rosacea pathogenesis, abnormal innate immune mechanisms including overexpression of the Toll-like receptor (TLR) have been proposed. However, the links between glucocorticoid metabolism and innate immunity in the epidermis have not been elucidated.

OBJECTIVE

In order to understand the pathology by which rosacea symptoms are exacerbated by steroids and environment stimuli, we examined the molecular links between the innate immune system and glucocorticoid synthesis in epidermis.

METHODS

We examined the expression of glucocorticoid-synthetic enzymes in rosacea skin. We stimulated epidermal keratinocytes by TLR ligands and examined the regulation of glucocorticoid-synthetic enzymes. We also employed siRNA and adenovirus vectors to knockdown and transduce TLR molecules, respectively.

RESULTS

Rosacea epidermis showed high HSD11B1 in the granular layer. Among TLR ligands, TLR3 ligand Poly(I:C) enhanced the expression of multiple glucocorticoid-synthetic enzymes including HSD11B1 and CYP11A1, and increased cortisol in the cultured media. Induction of HSD11B1 by Poly(I:C) was abolished by pretreatment with TLR3 siRNA. Transfection with an adenoviral vector incorporating TLR3 enhanced HSD11B1 and CYP11A1 protein expression by Poly(I:C). In addition, cell staining revealed increased expression of HSD11B1 and CYP11A1 proteins in the group transfected with TLR3 under the same conditions.

CONCLUSION

TLR3-stimulated epidermal keratinocytes and rosacea epidermis enhance the expression of glucocorticoid-synthetic enzymes, which would promote cortisol activation in the epidermis. The innate immunity modulates glucocorticoid-synthetic enzymes expression via the TLR3 pathway in epidermal keratinocytes.

Inhibitory Effects of Prunella vulgaris L. Extract on 11β-HSD1 in Human Skin Cells

Glucocorticoids are a risk factor for age-induced skin structure and function defects, and the glucocorticoid-activating enzyme, 11β-hydroxysteroid dehydrogenase 1 (11β-HSD1), represents a promising therapeutic target. Prunella vulgaris L. (PV) is a perennial and an edible herbaceous plant normally cultivated in Asia and Europe. A recent study demonstrated a broad range of biological activities of PV including immune modulatory, antiviral, antiallergic, anti-inflammatory, antioxidant, and antidiabetic. However, little is known about the inhibitory effect of PV on 11β-HSD1. In this study, we investigated the inhibitory effect of Prunella vulgaris L. extract (PVE) and the underlying mechanism of 11β-HSD11 inhibition. Consistent with these results, cortisol levels were also reduced by PVE in vitro. The cortisone-induced translocation of glucocorticoids receptor (GR) was also attenuated. In addition, PVE inhibited a cortisone-mediated decrease in collagen content in skin. Collectively, these results suggest the beneficial effects of PVE in maintaining skin integrity.

Design, synthesis, and biological evaluation of novel selective peptide inhibitors of 11β-hydroxysteroid dehydrogenase 1

The enzyme 11β-HSD1 plays a crucial role in the tissue-specific regulation of cortisol levels and it has been associated with various diseases. Inhibition of 11β-HSD1 is an attractive intervention strategy and the discovery of novel selective 11β-HSD1 inhibitors is of high relevance. In this study, we identified and evaluated a new series of selective peptide 11β-HSD1 inhibitors with potential for skin care applications. This novel scaffold was designed with the aid of molecular modeling and two previously reported inhibitors. SAR optimization yielded highly active peptides (IC₅₀ below 400 nM) that were inactive at 1 µM concentration against structurally related enzymes (11β-HSD2, 17β-HSD1 and 17β-HSD2). The best performing peptides inhibited the conversion of cortisone into cortisol in primary human keratinocytes and the most active compound, 5d, was further shown to reverse cortisone-induced collagen damage in human ex-vivo tissue.

Psychological Stress Deteriorates Skin Barrier Function by Activating 11β-Hydroxysteroid Dehydrogenase 1 and the HPA Axis

Psychological stress (PS) increases endogenous glucocorticoids (GC) by activating the hypothalamic-pituitary-adrenal axis. The negative effects of GC on skin barrier function under PS have been well-established. However, endogenous GC can also be active when cortisone (inactive form) is converted to cortisol (active form) by 11β-hydroxysteroid dehydrogenase type I (11ß-HSD1) in the peripheral tissue. Here, we evaluated the changes in 11ß-HSD1 and barrier function under PS. Elevated 11ß-HSD1 in oral mucosa correlated with increased cortisol in the stratum corneum and deteriorated barrier function. Expression of 11ß-HSD1 in the oral mucosa correlated with that in the epidermal keratinocytes. We further investigated whether barrier function improved when PS was relieved using a selective serotonin reuptake inhibitor (SSRI) in patients with anxiety. Decreased 11ß-HSD1 and improved barrier function were observed after SSRI treatment. The collective findings suggest that elevated 11ß-HSD1 under PS increases the level of cutaneous GC and eventually impairs barrier function. PS-alleviating drugs, such as SSRI, may help to treat PS-aggravated skin diseases.

Local cortisol activation is involved in EGF-induced immunosuppression

The major effects of the epidermal growth factor receptor (EGFR) signalling pathway on keratinocytes are cell proliferation, cell differentiation, and wound healing. In addition to these effects, an immunosuppressive effect of EGFR signalling has been reported. However, the precise mechanism of immunosuppression by EGFR signalling is not well understood. In this study, we clarified the involvement of increased local cortisol activation in EGFR signalling-induced immunosuppression in keratinocytes. EGF treatment up-regulated the expression of 11β-hydroxysteroid dehydrogenase 1 (11β-HSD1) and supernatant cortisol levels in a dose-dependent manner in keratinocytes. 11β-HSD1 is an enzyme that catalyses the conversion of cellular hormonally inactive cortisone into active cortisol. qRT-PCR and ELISA assays indicated that EGF significantly decreased tumour necrosis factor α (TNF- α)-induced interleukin-6 (IL-6) expression in keratinocytes. Similarly, 11β-HSD1 overexpression significantly decreased TNF-α-induced IL-6 expression. We evaluated the role of 11β-HSD1 in immunosuppression through EGFR signalling. Blockade of 11β-HSD1 via 11β-HSD1 inhibitor reversed both the expression and production of TNF-α-induced IL-6, which was decreased by EGF in keratinocytes. Therefore, increased local cortisol activation by 11β-HSD1 is involved in EGFR signalling-induced immunosuppression in keratinocytes. Finally, we evaluated whether EGFR inhibition by cetuximab affects the expression of 11β-HSD1. We found that 0.1 µg cetuximab decreased 11β-HSD1 transcript levels in keratinocytes. The changes in 11β-HSD1 were more apparent in TNF-α-treated cells. As 11β-HSD1 expression in keratinocytes is associated with inflammation and cell proliferation, this mechanism may be associated with adverse skin reactions observed in patients treated with EGFR inhibitors.

Attenuated Activation of Homeostatic Glucocorticoid in Keratinocytes Induces Alloknesis via Aberrant Artemin Production

Intense chronic itch significantly reduces quality of life for atopic dermatitis patients, impairing daily activity. Although abnormal itch sensation can be induced by innocuous stimuli, known as alloknesis, the mechanisms driving this process remain obscure. Psychological and environmental stimuli are known to aggravate atopic dermatitis symptoms. Recently, the enzyme 11β-hydroxysteroid dehydrogenase-1 (HSD11β1), which is expressed in keratinocytes, has been implicated in maintaining homeostasis against environmental stimuli by activating endogenous glucocorticoids. To investigate the role of HSD11β1 in keratinocytes, we generated keratinocyte-specific Hsd11b1-knockout (Hsd11b1^KC-/-) mice and analyzed skin phenotype. Hsd11b1^KC-/- mice exhibited abnormal cutaneous innervation and skin sensitivity, including light mechanical stimulus-evoked itch (i.e., alloknesis). Attenuated endogenous glucocorticoid activation induced by aberrant artemin production in keratinocytes was involved in alloknesis in Hsd11b1^KC-/- mice. Finally, we observed a significant negative correlation between expression of HSD11β1 and artemin in human skin with and without AD. These results suggest that endogenous glucocorticoids that maintain skin homeostasis in the epidermis affect both skin innervation and cutaneous sensation. Modulation of HSD11β1 activation could be a therapeutic target for sensitive or itchy skin.

Topical 11β-Hydroxysteroid Dehydrogenase Type 1 Inhibition Corrects Cutaneous Features of Systemic Glucocorticoid Excess in Female Mice

Glucocorticoid (GC) excess drives multiple cutaneous adverse effects, including skin thinning and poor wound healing. The ubiquitously expressed enzyme 11β-hydroxysteroid dehydrogenase type 1 (11β-HSD1) activates mouse corticosterone from 11-dehydrocorticosterone (and human cortisol from cortisone). We previously demonstrated elevated 11β-HSD1 activity during mouse wound healing, but the interplay between cutaneous 11β-HSD1 and systemic GC excess is unexplored. Here, we examined effects of 11β-HSD1 inhibition by carbenoxolone (CBX) in mice treated with corticosterone (CORT) or vehicle for 6 weeks. Mice were treated bidaily with topical CBX or vehicle (VEH) 7 days before wounding and during wound healing. CORT mice displayed skin thinning and impaired wound healing but also increased epidermal integrity. 11β-HSD1 activity was elevated in unwounded CORT skin and was inhibited by CBX. CORT mice treated with CBX displayed 51%, 59%, and 100% normalization of wound healing, epidermal thickness, and epidermal integrity, respectively. Gene expression studies revealed normalization of interleukin 6, keratinocyte growth factor, collagen 1, collagen 3, matrix metalloproteinase 9, and tissue inhibitor of matrix metalloproteinase 4 by CBX during wound healing. Importantly, proinflammatory cytokine expression and resolution of inflammation were unaffected by 11β-HSD1 inhibition. CBX did not regulate skin function or wound healing in the absence of CORT. Our findings demonstrate that 11β-HSD1 inhibition can limit the cutaneous effects of GC excess, which may improve the safety profile of systemic steroids and the prognosis of chronic wounds.

Association between Stress and the HPA Axis in the Atopic Dermatitis

The hypothalamic–pituitary–adrenal (HPA) axis is one of the body’s neuroendocrine networks that responds to psychological stress (PS). In the skin, there exists a peripheral HPA axis similar to the central axis. Glucocorticoids (GCs) are key effector molecules of the HPA axis and are essential for cutaneous homeostasis. Atopic dermatitis (AD) is a condition typically characterized by a chronic relapsing course that often results in PS. HPA dysfunction is present in AD patients by the decreased response of GCs elevation to stress as compared to those unaffected by AD. Nevertheless, in skin, acute PS activates several metabolic responses that are of immediate benefit to the host. During the acute phase of PS, increased endogenous GCs have been shown to provide benefit rather than by aggravating cutaneous inflammatory dermatoses. However, a chronic T helper cell type 2 (Th2) predominant cytokine profile acts as a negative feedback loop to blunt the HPA axis response in AD. In this article, we reviewed the role of CRF, pro-opiomelanocortin (POMC)-derived peptides, GCs of the HPA, and 11β-hydroxysteroid dehydrogenase 1 (11β-HSD1) in AD, with a discussion of the pathogenetic mechanisms of inflammation and skin barrier functions, including antimicrobial defense, and their association with PS.

Neuroendocrine factors: The missing link in non‑melanoma skin cancer (Review)

Non‑melanoma skin cancer (NMSC) is the most common form of cancer worldwide, comprising 95% of all cutaneous malignancies and approximately 40% of all cancers. In spite of intensive efforts aimed towards awareness campaigns and sun‑protective measures, epidemiological data indicate an increase in the incidence of NMSC. This category of skin cancers has many common environmental triggers. Arising primarily on sun‑exposed skin, it has been shown that ultraviolet radiation is, in the majority of cases, the main trigger involved in the pathogenesis of NMSC. Aside from the well‑known etiopathogenic factors, studies have indicated that several neuroactive factors are involved in the carcinogenesis of two of the most common types of NMSC, namely basal cell carcinoma (BCC) and squamous cell carcinoma (SCC), with the exception of penile SCC, for which a paucity of specific data on their pathogenic role exists. The complex interaction between the peripheral nervous system and target cells in the skin appears to be mediated by locally released neuroendocrine factors, such as catecholamines, substance P, calcitonin gene‑related peptide and somatostatin, as well as neurohormones, such as proopiomelanocortin and its derived peptides, α‑melanocyte‑stimulating hormone and adrenocorticotropin. All these factors have been, at least at some point, a subject of debate regarding their precise role in the pathogenesis of NMSC. There is also a significant body of evidence indicating that psychological stress is a crucial impact factor influencing the course of skin cancers, including SCC and BCC. Numerous studies have suggested that neuroendocrine factor dysregulation, as observed in stress reactions, may be involved in tumorigenesis, accelerating the development and progression, and suppressing the regression of NMSC. Further studies are required in order to elucidate the exact mechanisms through which neuroactive molecules promote or inhibit cutaneous carcinogenesis, as this could lead to the development of more sophisticated and tailored treatment protocols, as well as open new perspectives in skin cancer research.

Characterisation of the cancer-associated glucocorticoid system: key role of 11β-hydroxysteroid dehydrogenase type 2

Background:

Recent studies have shown that production of cortisol not only takes place in several non-adrenal peripheral tissues such as epithelial cells but, also, the local inter-conversion between cortisone and cortisol is regulated by the 11β-hydroxysteroid dehydrogenases (11β-HSDs). However, little is known about the activity of this non-adrenal glucocorticoid system in cancers.

Methods:

The presence of a functioning glucocorticoid system was assessed in human skin squamous cell carcinoma (SCC) and melanoma and further, in 16 epithelial cell lines from 8 different tissue types using ELISA, western blotting and immunofluorescence. 11β-HSD2 was inhibited both pharmacologically and by siRNA technology. Naïve CD8⁺ T cells were used to test the paracrine effects of cancer-derived cortisol on the immune system in vitro. Functional assays included cell–cell adhesion and cohesion in two- and three-dimensional models. Immunohistochemical data of 11β-HSD expression were generated using tissue microarrays of 40 cases of human SCCs as well as a database featuring 315 cancer cases from 15 different tissues.

Results:

We show that cortisol production is a common feature of malignant cells and has paracrine functions. Cortisol production correlated with the magnitude of glucocorticoid receptor (GR)-dependent inhibition of tumour-specific CD8⁺ T cells in vitro. 11β-HSDs were detectable in human skin SCCs and melanoma. Analyses of publicly available protein expression data of 11β-HSDs demonstrated that 11β-HSD1 and -HSD2 were dysregulated in the majority (73%) of malignancies. Pharmacological manipulation of 11β-HSD2 activity by 18β-glycyrrhetinic acid (GA) and silencing by specific siRNAs modulated the bioavailability of cortisol. Cortisol also acted in an autocrine manner and promoted cell invasion in vitro and cell–cell adhesion and cohesion in two- and three-dimensional models. Immunohistochemical analyses using tissue microarrays showed that expression of 11β-HSD2 was significantly reduced in human SCCs of the skin.

Conclusions:

The results demonstrate evidence of a cancer-associated glucocorticoid system and show for the first time, the functional significance of cancer-derived cortisol in tumour progression.

11β-hydroxysteroid dehydrogenases-2 decreases the apoptosis of MC3T3/MLO-Y4 cells induced by glucocorticoids

The aim of the present study was to confirm the role of 11β-hydroxysteroid dehydrogenases type 2(11β-HSD-2) in steroid induced osteonecrosis of the femoral head(SANFH). We cultured mouse bone-like cells (MLO-Y4) and mouse osteoblast-like cells (MC3T3-E1). After overexpressed 11β-HSD-2 successfully, we induced cell apoptosis by dexamethasone (DXM). The level of cell apoptosis, the expression of Bcl-2 in MLO-Y4 cells and the expression of Fas and caspase8 in MC3T3-E1 cells were detected. Then, we constructed 11β-HSD-2 siRNA plasmid and represented it on MLO-Y4/MC3T3-E1 Cells, to down-regulate the 11β-HSD-2 expression. After that, we used dexamethasone to induce cell apoptosis. The level of cell apoptosis, the expression of Bcl-2 in MLO-Y4 cells and the expression of Fas and caspase8 in MC3T3-E1 cells were detected again. In the overexpression model of cells, we found that the amount of cell apoptosis, the expression of Fas and caspase8 in MC3T3-E1 cells are lower than that of control groups. The amount of cell apoptosis, the expression of Fas and caspase8 in MC3T3-E1 cells were more than before when we reduced the expression of 11β-HSD-2. In our study, we concluded that 11β-HSD-2 plays an important role in the development of bone or osteoblast cell apoptosis, and the decreased expression of 11β-HSD-2 may aggravate steroid induced bone/osteoblast cell apoptosis.

An integrative metabolomics and transcriptomics study to identify metabolic alterations in aged skin of humans in vivo

Background

Aging human skin undergoes significant morphological and functional changes such as wrinkle formation, reduced wound healing capacity, and altered epidermal barrier function. Besides known age-related alterations like DNA-methylation changes, metabolic adaptations have been recently linked to impaired skin function in elder humans. Understanding of these metabolic adaptations in aged skin is of special interest to devise topical treatments that potentially reverse or alleviate age-dependent skin deterioration and the occurrence of skin disorders.

Results

We investigated the global metabolic adaptions in human skin during aging with a combined transcriptomic and metabolomic approach applied to epidermal tissue samples of young and old human volunteers. Our analysis confirmed known age-dependent metabolic alterations, e.g. reduction of coenzyme Q10 levels, and also revealed novel age effects that are seemingly important for skin maintenance. Integration of donor-matched transcriptome and metabolome data highlighted transcriptionally-driven alterations of metabolism during aging such as altered activity in upper glycolysis and glycerolipid biosynthesis or decreased protein and polyamine biosynthesis. Together, we identified several age-dependent metabolic alterations that might affect cellular signaling, epidermal barrier function, and skin structure and morphology.

Conclusions

Our study provides a global resource on the metabolic adaptations and its transcriptional regulation during aging of human skin. Thus, it represents a first step towards an understanding of the impact of metabolism on impaired skin function in aged humans and therefore will potentially lead to improved treatments of age related skin disorders.

Electronic supplementary material

The online version of this article (doi:10.1186/s12864-017-3547-3) contains supplementary material, which is available to authorized users.

Novel 11β-hydroxysteroid dehydrogenase 1 inhibitors reduce cortisol levels in keratinocytes and improve dermal collagen content in human ex vivo skin after exposure to cortisone and UV

Activity and selectivity assessment of new bi-aryl amide 11β-hydroxysteroid dehydrogenase 1 (11β-HSD1) inhibitors, prepared in a modular manner via Suzuki cross-coupling, are described. Several compounds inhibiting 11β-HSD1 at nanomolar concentrations were identified. Compounds 2b, 3e, 7b and 12e were shown to selectively inhibit 11β-HSD1 over 11β-HSD2, 17β-HSD1 and 17β-HSD2. These inhibitors also potently inhibited 11β-HSD1 activity in intact HEK-293 cells expressing the recombinant enzyme and in intact primary human keratinocytes expressing endogenous 11β-HSD1. Moreover, compounds 2b, 3e and 12e were tested for their activity in human skin biopsies. They were able to prevent, at least in part, both the cortisone- and the UV-mediated decreases in collagen content. Thus, inhibition of 11β-HSD1 by these compounds can be further investigated to delay or prevent UV-mediated skin damage and skin aging.

Piper betel leaves induces wound healing activity via proliferation of fibroblasts and reducing 11β hydroxysteriod dehydrogenase-1 expression in diabetic rat

BACKGROUND

Increased oxidative stress and stress enzyme 11β hydroxysteriod dehydrogenase-1 (11β HSD-1) served as the major contributing factors for delayed wound healing in diabetes mellitus (DM). Piper betel (PB) leaves are reported to possess anti-diabetic, anti-oxidant and anti-microbial properties.

OBJECTIVE

The objective was to investigate the effectiveness of topical application of PB leaves extract on oxidative stress and 11β hydroxysteriod dehydrogenase-1 (11β HSD-1) expression in diabetic wounds.

MATERIALS AND METHODS

A total 64 male Sprague-Dawley rats were randomly chosen. The experimental rats received a single intramuscular injection of streptozotocin (45 mg/kg). Four full thickness (6 mm) wounds were created on the dorsum of each rat. The animals were equally divided (n = 8) into four groups based on the days of treatment (i.e. days 3 and 7): Control (Ctrl), diabetic untreated (DM-Ctrl), diabetic treated with 1% silver nitrate cream (DM-SN) and diabetic treated with 50 mg/kg of P. betel leaves extract (DM-PB). The rats were sacrificed on day 3 and 7 of post wound creations.

RESULTS

Following day 7 wound creation, topical application of PB extract showed significant increase in hydroxyproline content, superoxide dismutase (SOD) level and decreased malondialdehyde (MDA) level, 11β-HSD-1 enzyme expression in the diabetic wounds compared to untreated diabetic wounds. The results were supported by the observations based on histological and ultrastructural features of the wound tissue applied with PB extract.

CONCLUSION

PB leaves extract improved the delayed wound healing in diabetes mellitus by decreasing the oxidative stress markers and 11β HSD-1 expression.

Local cortisol/corticosterone activation in skin physiology and pathology

Cortisol and corticosterone are the endogenous glucocorticoids (GCs) in humans and rodents, respectively. Systemic GC is released through the hypothalamic-pituitary-adrenal (HPA) axis in response to various stressors. Over the last decade, extra-adrenal production/activation of cortisol/corticosterone has been reported in many tissues. The enzyme that catalyzes the conversion of hormonally inactive cortisone/11-dehydrocorticosterone (11-DHC) into active cortisol/corticosterone in cells is 11β-hydroxysteroid dehydrogenase (11β-HSD). The 11β-HSD1 isoform is predominantly a reductase, which catalyzes nicotinamide adenine dinucleotide phosphate hydrogen-dependent conversion of cortisone/11-DHC to cortisol/corticosterone, and is widely expressed and present at the highest levels in the liver, lungs, adipose tissues, ovaries, and central nervous system. The 11β-HSD2 isoform, which catalyzes nicotinamide adenine dinucleotide⁺-dependent inactivation of cortisol/corticosterone to cortisone/11-DHC, is highly expressed in distal nephrons, the colon, sweat glands, and the placenta. In healthy skin, 11β-HSD1 is expressed in the epidermis and in dermal fibroblasts. On the other hand, 11β-HSD2 is expressed in sweat glands but not in the epidermis. The role of 11β-HSD in skin physiology and pathology has been reported recently. In this review, we summarize the recently reported role of 11β-HSD in the skin, focusing on its function in cell proliferation, wound healing, inflammation, and aging.

Local Glucocorticoid Activation by 11β-Hydroxysteroid Dehydrogenase 1 in Keratinocytes: The Role in Hapten-Induced Dermatitis

Over the past decade, extra-adrenal cortisol production was reported in various tissues. The enzyme that catalyzes the conversion of hormonally inactive cortisone into active cortisol in cells is 11β-hydroxysteroid dehydrogenase 1 (11β-HSD1). We recently reported that 11β-HSD1 is also expressed in keratinocytes and regulates inflammation and keratinocyte proliferation. To investigate the function of 11β-HSD1 in keratinocytes during inflammation in vivo, we created keratinocyte-specific 11β-HSD1 knockout (K5-Hsd11b1-KO) mice and analyzed the inflammatory response in models of hapten-induced contact irritant dermatitis. K5-Hsd11b1-KO mice showed enhanced ear swelling in low-dose oxazolone-, 2,4,6-trinitro-1-chlorobenzene (TNCB)-, and 2,4-dinitrofluorobenzene-induced irritant dermatitis associated with increased inflammatory cell infiltration. Topical application of corticosterone dose dependently suppressed TNCB-induced ear swelling and cytokine expression. Similarly in mouse keratinocytes in vitro, corticosterone dose dependently suppressed 2,4,6-trinitrobenzenesulfonic acid-induced IL-1α and IL-1β expression. The effect of 11-dehydrocorticosterone was attenuated in TNCB-induced irritant dermatitis in K5-Hsd11b1-KO mice compared with wild-type mice. In human samples, 11β-HSD1 expression was decreased in epidermis of psoriasis vulgaris compared with healthy skin. Taken together, these data suggest that corticosterone activation by 11β-HSD1 in keratinocytes suppresses hapten-induced irritant dermatitis through suppression of expression of cytokines, such as IL-1α and IL-1β, in keratinocytes.

Local corticosterone activation by 11β-hydroxysteroid dehydrogenase 1 in keratinocytes: the role in narrow-band UVB-induced dermatitis

Keratinocytes are known to synthesize cortisol through activation of the enzyme 11β-hydroxysteroid dehydrogenase 1 (11β-HSD1). To confirm the function of 11β-HSD1 in keratinocytes during inflammation in vivo, we created keratinocyte-specific-11β-HSD1 knockout mice (K5-Hsd11b1-KO mice) and analyzed the response to narrow-band ultraviolet B (NB-UVB) irradiation. Firstly, we measured the mRNA and protein levels of 11β-HSD1 following NB-UVB irradiation and found that the expression of 11β-HSD1 in keratinocytes of mouse ear skin was enhanced at 3 and 24 hours after 250 mJ/cm(2), 500 mJ/cm(2), 1 J/cm(2), and 2 J/cm(2) NB-UVB irradiation. Next, we determined that 24 hours after exposure to 1 J/cm(2) NB-UVB irradiation, the numbers of F4/80-, CD45-, and Gr-1-positive cells were increased in K5-Hsd11b1-KO mice compared to wild type (WT) mice. Furthermore, the expression of the chemokine (C-X-C-motif) ligand 1 (CXCL1) and interleukin (IL)-6 was also significantly enhanced in NB-UVB-irradiated K5-Hsd11b1-KO mice compared with WT mice. In addition, activation of nuclear factor-kappa B (NF-κB) after NB-UVB irradiation was enhanced in K5-Hsd11b1-KO mice compared to that in WT mice. Thus, NB-UVB-induced inflammation is augmented in K5-Hsd11b1-KO mice compared with WT mice. These results indicate that 11β-HSD1 may suppress NB-UVB-induced inflammation via inhibition of NF-κB activation.

On the role of skin in the regulation of local and systemic steroidogenic activities

The mammalian skin is a heterogeneous organ/tissue covering our body, showing regional variations and endowed with neuroendocrine activities. The latter is represented by its ability to produce and respond to neurotransmitters, neuropeptides, hormones and neurohormones, of which expression and phenotypic activities can be modified by ultraviolet radiation, chemical and physical factors, as well as by cytokines. The neuroendocrine contribution to the responses of skin to stress is served, in part, by local synthesis of all elements of the hypothalamo-pituitary-adrenal axis. Skin with subcutis can also be classified as a steroidogenic tissue because it expresses the enzyme, CYP11A1, which initiates steroid synthesis by converting cholesterol to pregnenolone, as in other steroidogenic tissues. Pregnenolone, or steroidal precursors from the circulation, are further transformed in the skin to corticosteroids or sex hormones. Furthermore, in the skin CYP11A1 acts on 7-dehydrocholesterol with production of 7-dehydropregnolone, which can be further metabolized to other Δ7steroids, which after exposure to UVB undergo photochemical transformation to vitamin D like compounds with a short side chain. Vitamin D and lumisterol, produced in the skin after exposure to UVB, are also metabolized by CYP11A1 to several hydroxyderivatives. Vitamin D hydroxyderivatives generated by action of CYP11A1 are biologically active and are subject to further hydroxylations by CYP27B1, CYP27A1 and CP24A. Establishment of which intermediates are produced in the epidermis in vivo and whether they circulate on the systemic level represent a future research challenge. In summary, skin is a neuroendocrine organ endowed with steroid/secosteroidogenic activities.

Differential expression of 11β-hydroxysteroid dehydrogenase type 1 and 2 in mild and moderate/severe persistent allergic nasal mucosa and regulation of their expression by Th2 cytokines: asthma and rhinitis

BACKGROUND

Glucocorticoids are used to treat allergic rhinitis, but the mechanisms by which they induce disease remission are unclear. 11β-hydroxysteroid dehydrogenase (11β-HSD) is a tissue-specific regulator of glucocorticoid responses, inducing the interconversion of inactive and active glucocorticoids.

OBJECTIVE

We analysed the expression and distribution patterns of 11β-HSD1, 11β-HSD2, and steroidogenic enzymes in normal and allergic nasal mucosa, and cytokine-driven regulation of their expression. The production levels of cortisol in normal, allergic nasal mucosa and in cultured epithelial cells stimulated with cytokines were also determined.

METHODS

The expression levels of 11β-HSD1, 11β-HSD2, steroidogenic enzymes (CYP11B1, CYP11A1), and cortisol in normal, mild, and moderate/severe persistent allergic nasal mucosa were assessed by real-time PCR, Western blot, immunohistochemistry, and ELISA. The expression levels of 11β-HSD1, 11β-HSD2, CYP11B1, CYP11A1, and cortisol were also determined in cultured nasal epithelial cell treated with IL-4, IL-5, IL-13, IL-17A, and IFN-γ. Conversion ratio of cortisone to cortisol was evaluated using siRNA technique, 11β-HSD1 inhibitor, and the measurement of 11β-HSD1 activity.

RESULTS

The expression levels of 11β-HSD1, CYP11B1, and cortisol were up-regulated in mild and moderate/severe persistent allergic nasal mucosa. By contrast, 11β-HSD2 expression was decreased in allergic nasal mucosa. In cultured epithelial cells treated with IL-4, IL-5, IL-13, and IL-17A, 11β-HSD1 expression and activity increased in parallel with the expression levels of CYP11B1 and cortisol, but the production of 11β-HSD2 decreased. CYP11A1 expression level was not changed in allergic nasal mucosa or in response to stimulation with cytokines. SiRNA technique or the measurement of 11β-HSD1 activity showed that nasal epithelium activates cortisone to cortisol in a 11β-HSD-dependent manner.

CONCLUSIONS AND CLINICAL RELEVANCE

These results indicate that the localized anti-inflammatory effects of glucocorticoids are regulated by inflammatory cytokines, which can modulate the expression of 11β-HSD1, 11β-HSD2, and CYP11B1, and by the intracellular concentrations of bioactive glucocorticoids.

Epithelialization in Wound Healing: A Comprehensive Review

Significance: Keratinocytes, a major cellular component of the epidermis, are responsible for restoring the epidermis after injury through a process termed epithelialization. This review will focus on the pivotal role of keratinocytes in epithelialization, including cellular processes and mechanisms of their regulation during re-epithelialization, and their cross talk with other cell types participating in wound healing. Recent Advances: Discoveries in epidermal stem cells, keratinocyte immune function, and the role of the epidermis as an independent neuroendocrine organ will be reviewed. Novel mechanisms of gene expression regulation important for re-epithelialization, including microRNAs and histone modifications, will also be discussed. Critical Issues: Epithelialization is an essential component of wound healing used as a defining parameter of a successful wound closure. A wound cannot be considered healed in the absence of re-epithelialization. The epithelialization process is impaired in all types of chronic wounds. Future Directions: A comprehensive understanding of the epithelialization process will ultimately lead to the development of novel therapeutic approaches to promote wound closure.

Cutaneous glucocorticosteroidogenesis: securing local homeostasis and the skin integrity

Human skin has the ability to synthesize glucocorticoids de novo from cholesterol or from steroid intermediates of systemic origin. By interacting with glucocorticoid receptors, they regulate skin immune functions as well as functions and phenotype of the epidermal, dermal and adnexal compartments. Most of the biochemical (enzyme and transporter activities) and regulatory (neuropeptides mediated activation of cAMP and protein kinase A dependent pathways) principles of steroidogenesis in the skin are similar to those operating in classical steroidogenic organs. However, there are also significant differences determined by the close proximity of synthesis and action (even within the same cells) allowing para-, auto- or intracrine modes of regulation. We also propose that ultraviolet light B (UVB) can regulate the availability of 7-dehydrocholesterol for transformation to cholesterol with its further metabolism to steroids, oxysterols or ∆7 steroids, because of its transformation to vitamin D3. In addition, UVB can rearrange locally produced ∆7 steroids to the corresponding secosteroids with a short- or no-side chain. Thus, different mechanisms of regulation occur in the skin that can be either stochastic or structuralized. We propose that local glucocorticosteroidogenic systems and their regulators, in concert with cognate receptors operate to stabilize skin homeostasis and prevent or attenuate skin pathology.

Increased glucocorticoid activation during mouse skin wound healing

Glucocorticoid (GC) excess inhibits wound healing causing increased patient discomfort and infection risk. 11β-hydroxysteroid dehydrogenase type 1 (11β-HSD1) activates GCs (converting 11-dehydrocorticosterone to corticosterone in rodents) in many tissues including skin, where de novo steroidogenesis from cholesterol has also been reported. To examine the regulation of 11β-HSD1 and steroidogenic enzyme expression during wound healing, 5 mm wounds were generated in female SKH1 mice and compared at days 0, 2, 4, 8, 14, and 21 relative to unwounded skin. 11β-HSD1 expression (mRNA and protein) and enzyme activity were elevated at 2 and 4 days post-wounding, with 11β-HSD1 localizing to infiltrating inflammatory cells. 11β-HSD2 (GC-deactivating) mRNA expression and activity were undetectable. Although several steroidogenic enzymes displayed variable expression during healing, expression of the final enzyme required for the conversion of 11-deoxycorticosterone to corticosterone, 11β-hydroxylase (CYP11B1), was lacking in unwounded skin and post-wounding. Consequently, 11-deoxycorticosterone was the principal progesterone metabolite in mouse skin before and after wounding. Our findings demonstrate that 11β-HSD1 activates considerably more corticosterone than is generated de novo from progesterone in mouse skin and drives GC exposure during healing, demonstrating the basis for 11β-HSD1 inhibitors to accelerate wound repair.

11β-hydroxysteroid dehydrogenase 1 specific inhibitor increased dermal collagen content and promotes fibroblast proliferation

Glucocorticoids (GCs) are one of the most effective anti-inflammatory drugs for treating acute and chronic inflammatory diseases. However, several studies have shown that GCs alter collagen metabolism in the skin and induce skin atrophy. Cortisol is the endogenous GC that is released in response to various stressors. Over the last decade, extraadrenal cortisol production in various tissues has been reported. Skin also synthesizes cortisol through a de novo pathway and through an activating enzyme. 11β-hydroxysteroid dehydrogenase 1 (11β-HSD1) is the enzyme that catalyzes the conversion of hormonally inactive cortisone to active cortisol in cells. We previously found that 11β-HSD1 negatively regulates proliferation of keratinocytes. To determine the function of 11β-HSD1 in dermal fibroblasts and collagen metabolism, the effect of a selective 11β-HSD1 inhibitor was studied in mouse tissues and dermal fibroblasts. The expression of 11β-HSD1 increased with age in mouse skin. Subcutaneous injection of a selective 11β-HSD1 inhibitor increased dermal thickness and collagen content in the mouse skin. In vitro, proliferation of dermal fibroblasts derived from 11β-HSD1 null mice (Hsd11b1^−/− mice) was significantly increased compared with fibroblasts from wild-type mice. However, in vivo, dermal thickness of Hsd11b1^−/− mice was not altered in 3-month-old and 1-year-old mouse skin compared with wild-type mouse skin. These in vivo findings suggest the presence of compensatory mechanisms in Hsd11b1^−/− mice. Our findings suggest that 11β-HSD1 inhibition may reverse the decreased collagen content observed in intrinsically and extrinsically aged skin and in skin atrophy that is induced by GC treatment.

Pathogenesis of hepatic steatosis: The link between hypercortisolism and non-alcoholic fatty liver disease

Based on the available literature, non alcoholic fatty liver disease or generally speaking, hepatic steatosis, is more frequent among people with diabetes and obesity, and is almost universally present amongst morbidly obese diabetic patients. Non alcoholic fatty liver disease is being increasingly recognized as a common liver condition in the developed world, with non alcoholic steatohepatitis projected to be the leading cause of liver transplantation. Previous data report that only 20% of patients with Cushing’s syndrome have hepatic steatosis. Aiming at clarifying the reasons whereby patients suffering from Cushing’s syndrome - a condition characterized by profound metabolic changes - present low prevalence of hepatic steatosis, the Authors reviewed the current concepts on the link between hypercortisolism and obesity/metabolic syndrome. They hypothesize that this low prevalence of fat accumulation in the liver of patients with Cushing’s syndrome could result from the inhibition of the so-called low-grade chronic-inflammation, mainly mediated by Interleukin 6, due to an excess of cortisol, a hormone characterized by an anti-inflammatory effect. The Cushing’s syndrome, speculatively considered as an in vivo model of the hepatic steatosis, could also help clarify the mechanisms of non alcoholic fatty liver disease.

11β-hydroxysteroid dehydrogenases: intracellular gate-keepers of tissue glucocorticoid action

Glucocorticoid action on target tissues is determined by the density of "nuclear" receptors and intracellular metabolism by the two isozymes of 11β-hydroxysteroid dehydrogenase (11β-HSD) which catalyze interconversion of active cortisol and corticosterone with inert cortisone and 11-dehydrocorticosterone. 11β-HSD type 1, a predominant reductase in most intact cells, catalyzes the regeneration of active glucocorticoids, thus amplifying cellular action. 11β-HSD1 is widely expressed in liver, adipose tissue, muscle, pancreatic islets, adult brain, inflammatory cells, and gonads. 11β-HSD1 is selectively elevated in adipose tissue in obesity where it contributes to metabolic complications. Similarly, 11β-HSD1 is elevated in the ageing brain where it exacerbates glucocorticoid-associated cognitive decline. Deficiency or selective inhibition of 11β-HSD1 improves multiple metabolic syndrome parameters in rodent models and human clinical trials and similarly improves cognitive function with ageing. The efficacy of inhibitors in human therapy remains unclear. 11β-HSD2 is a high-affinity dehydrogenase that inactivates glucocorticoids. In the distal nephron, 11β-HSD2 ensures that only aldosterone is an agonist at mineralocorticoid receptors (MR). 11β-HSD2 inhibition or genetic deficiency causes apparent mineralocorticoid excess and hypertension due to inappropriate glucocorticoid activation of renal MR. The placenta and fetus also highly express 11β-HSD2 which, by inactivating glucocorticoids, prevents premature maturation of fetal tissues and consequent developmental "programming." The role of 11β-HSD2 as a marker of programming is being explored. The 11β-HSDs thus illuminate the emerging biology of intracrine control, afford important insights into human pathogenesis, and offer new tissue-restricted therapeutic avenues.

Role of neuropeptides, neurotrophins, and neurohormones in skin wound healing

Due to the close interactions between the skin and peripheral nervous system, there is increasing evidence that the cutaneous innervation is an important modulator of the normal wound healing process. The communication between sensory neurons and skin cells involves a variety of molecules (neuropeptides, neurohormones, and neurotrophins) and their specific receptors expressed by both neuronal and nonneuronal skin cells. It is well established that neurotransmitters and nerve growth factors released in skin have immunoregulatory roles and can exert mitogenic actions; they could also influence the functions of the different skin cell types during the wound healing process.