Glucocorticoid Receptor Signaling in Skin Barrier Function

Glucocorticoids (GCs) are steroid hormones that regulate the physiology of all tissues and mediate stress responses. Synthetic GCs are commonly prescribed to treat chronic inflammatory conditions including the prevalent skin diseases—psoriasis and atopic dermatitis. GCs act through the GC receptor (GR, NR3C1), a ligand-activated transcription factor belonging to the nuclear hormone receptor superfamily. In skin, GC therapeutic efficacy is due to the antiproliferative and anti-inflammatory actions of GR; however, in the long term, these benefits are accompanied by adverse profiles including skin atrophy, increased fragility, dehydration, augmented susceptibility to infections, and delayed wound healing. While the therapeutic actions of GC treatments have been extensively studied, only more recently has the physiological role of GR been addressed in skin. In vivo and in vitro studies in mouse and man have revealed an important function for GR in skin homeostasis. In particular, the characterization of gain- or loss-of-function mouse models has demonstrated relevant roles for GR in skin pathophysiology. The actions of GR are context dependent, and in skin, it regulates different gene subsets and biological processes depending on developmental stage and physiological state. Finally, recent findings emphasize the relevance of local GC biosynthesis and appropriate GR expression in maintaining skin homeostasis

Epidermal inactivation of the glucocorticoid receptor triggers skin barrier defects and cutaneous inflammation.

9 páginas, 5 figuras. En material suplementario 7 figuras, 2 tablas.The glucocorticoid (GC) receptor (GR) mediates the effects of physiological and pharmacological GC ligands and has a major role in cutaneous pathophysiology. To dissect the epithelial versus mesenchymal contribution of GR in developing and adult skin, we generated mice with keratinocyte-restricted GR inactivation (GR epidermal knockout or GR(EKO) mice). Developing and early postnatal GR(EKO) mice exhibited impaired epidermal barrier formation, abnormal keratinocyte differentiation, hyperproliferation, and stratum corneum (SC) fragility. At birth, GR(EKO) epidermis showed altered levels of epidermal differentiation complex genes, proteases and protease inhibitors which participate in SC maintenance, and innate immunity genes. Many upregulated genes, including S100a8/a9 and Tslp, also have increased expression in inflammatory skin diseases. Infiltration of macrophages and degranulating mast cells were observed in newborn GR(EKO) skin, hallmarks of atopic dermatitis. In addition to increased extracellular signal-regulated kinase activation, GR(EKO) newborn and adult epidermis had increased levels of phosphorylated signal transducer and activator of transcription 3, a feature of psoriasis. Although adult GR(EKO) epidermis had a mild phenotype of increased proliferation, perturbation of skin homeostasis with detergent or phorbol ester triggered an exaggerated proliferative and hyperkeratotic response relative to wild type. Together, our results show that epidermal loss of GR provokes skin barrier defects and cutaneous inflammation.This work was supported by grant SAF2008-00540 and SAF2011-28115 of the Ministerio de Ciencia e Innovación/Economía y Competitividad from the Spanish Government and ACOMP2011/127 from Generalitat Valenciana. LMS holds a JAE-DOC contract partly supported by the EC and VL is a recipient of an FPI fellowship of MICINN (BES-2009-021944).Peer reviewe

Selective ablation of glucocorticoid receptor in mouse keratinocytes increases susceptibility to skin tumorigenesis.

9 páginas, 5 figuras. En material suplementario 5 figuras.We recently demonstrated that mice lacking the epidermal glucocorticoid (GC) receptor (GR) (GR epidermal knockout (GR(EKO)) mice) have developmental defects and sensitivity to epidermal challenge in adulthood. We examined the susceptibility of GR(EKO) mice to skin chemical carcinogenesis. GR(EKO) mice treated with a low dose of 12-dimethylbenz(a) anthracene (DMBA) followed by phorbol 12-myristate 13-acetate (PMA) promotion exhibited earlier papilloma formation with higher incidence and multiplicity relative to control littermates (CO). Augmented proliferation and inflammation and defective differentiation of GR(EKO) keratinocytes contributed to the phenotype, likely through increased AKT and STAT3 (signal transducer and activator of transcription 3) activities. GR(EKO) tumors exhibited signs of early malignization, including delocalized expression of laminin A, dermal invasion of keratin 5 (K5)-positive cells, K13 expression, and focal loss of E-cadherin. Cultured GR(EKO) keratinocytes were spindle like, with loss of E-cadherin and upregulation of smooth muscle actin (SMA) and Snail, suggesting partial epithelial-mesenchymal transition. A high DMBA dose followed by PMA promotion generated sebaceous adenomas and melanocytic foci in GR(EKO) and CO. Importantly, the number, growth kinetics, and extent of both tumor types increased in GR(EKO) mice, suggesting that in addition to regulating tumorigenesis from epidermal lineages, GR in keratinocytes is important for cross-talk with other skin cells. Altogether, our data reinforce the importance of GR in the pathogenesis of skin cancer.This work was supported by grant SAF2011-28115 of the Ministerio de Economía y Competitividad from the Spanish government. VL holds a fellowship from the MICINN (BES-2009-021944).Peer reviewe

Epidermal mineralocorticoid receptor plays beneficial and adverse effects in skin and mediates glucocorticoid responses

10 páginas, 6 figuras. Contiene material suplementarioGlucocorticoids (GCs) regulate skin homeostasis and combat cutaneous inflammatory diseases; however, adverse effects of chronic GC treatments limit their therapeutic use. GCs bind and activate the GC receptor and the mineralocorticoid receptor (MR), transcription factors that recognize identical hormone responsive elements. Whether epidermal MR mediates beneficial or deleterious GC effects is of great interest for improving GC-based skin therapies. MR epidermal knockout mice exhibited increased keratinocyte proliferation and differentiation and showed resistance to GC-induced epidermal thinning. However, crucially, loss of epidermal MR rendered mice more sensitive to inflammatory stimuli and skin damage. MR epidermal knockout mice showed increased susceptibility to phorbol 12-myristate 13-acetate-induced inflammation with higher cytokine induction. Likewise, cultured MR epidermal knockout keratinocytes had increased phorbol 12-myristate 13-acetate-induced NF-κB activation, highlighting an anti-inflammatory function for MR. GC-induced transcription was reduced in MR epidermal knockout keratinocytes, at least partially due to decreased recruitment of GC receptor to hormone responsive element-containing sequences. Our results support a role for epidermal MR in adult skin homeostasis and demonstrate nonredundant roles for MR and GC receptor in mediating GC actions.This work was supported by grant SAF2011-28115 and SAF2014-59474-R (MINECO, Spanish Government). JB and EC are recipients of FPI (BES-2012-0578) and FPU (AP201-06094) fellowships of MINECO, respectively. We thank COST ADMIRE BM- 1301 and NURCAMEIN (SAF2015-71878-REDT) for support for dissemination.Peer reviewe

The mineralocorticoid receptor plays a transient role in mouse skin development

3 páginas, 2 figuras. Contiene material suplemenarioGlucocorticoid (GC) hormones can bind two structurally and functionally related steroid receptors: the GC Receptor (GR or Nr3c1) and the mineralocorticoid receptor (MR or Nr3c2), which recognize the same DNA response elements and act as ligand-dependent transcription factors. While the crucial role of GR for skin homeostasis has been widely characterized, the exact role of MR in this tissue deserves further study. We assessed NR3C2 expression in developing and adult WT mouse skin and found a transient peak at embryonic day (E)16.5, which along with low levels of HSD11B2, the enzyme inactivating GCs, supports a role for GC-MR complexes in epidermal maturation. Consistent with this observation, MR-/- embryonic skin showed alterations in early epidermal differentiation that resolved postnatally. The lack of a more severe skin phenotype of MR-/- mice suggests functional compensation by GR in this tissue in the perinatal period.This work was supported by JSPS KAKENHI grant numbers 25870545 and 15K09772. Spanish Ministerio de Ciencia e Innovación. Grant Numbers: SAF2011-28115, SAF2014-59474-RPeer Reviewe

Kazrin, a novel periplakin-interacting protein associated with desmosomes and the keratinocyte plasma membrane

Periplakin forms part of the scaffold onto which the epidermal cornified envelope is assembled. The NH2-terminal 133 amino acids mediate association with the plasma membrane and bind a novel protein, kazrin. Kazrin is highly conserved and lacks homology to any known protein. There are four alternatively spliced transcripts, encoding three proteins with different NH2 termini. Kazrin is expressed in all layers of stratified squamous epithelia; it becomes membrane associated in the suprabasal layers, coincident with up-regulation of periplakin, and is incorporated into the cornified envelope of cultured keratinocytes. Kazrin colocalizes with periplakin and desmoplakin at desmosomes and with periplakin at the interdesmosomal plasma membrane, but its subcellular distribution is independent of periplakin. On transfection, all three kazrin isoforms have similar subcellular distributions. We conclude that kazrin is a novel component of desmosomes that associates with periplakin

Glucocorticoid Resistance: Interference between the Glucocorticoid Receptor and the MAPK Signalling Pathways

Endogenous glucocorticoids (GCs) are steroid hormones that signal in virtually all cell types to modulate tissue homeostasis throughout life. Also, synthetic GC derivatives (pharmacological GCs) constitute the first-line treatment in many chronic inflammatory conditions with unquestionable therapeutic benefits despite the associated adverse effects. GC actions are principally mediated through the GC receptor (GR), a ligand-dependent transcription factor. Despite the ubiquitous expression of GR, imbalances in GC signalling affect tissues differently, and with variable degrees of severity through mechanisms that are not completely deciphered. Congenital or acquired GC hypersensitivity or resistance syndromes can impact responsiveness to endogenous or pharmacological GCs, causing disease or inadequate therapeutic outcomes, respectively. Acquired GC resistance is defined as loss of efficacy or desensitization over time, and arises as a consequence of chronic inflammation, affecting around 30% of GC-treated patients. It represents an important limitation in the management of chronic inflammatory diseases and cancer, and can be due to impairment of multiple mechanisms along the GC signalling pathway. Among them, activation of the mitogen-activated protein kinases (MAPKs) and/or alterations in expression of their regulators, the dual-specific phosphatases (DUSPs), have been identified as common mechanisms of GC resistance. While many of the anti-inflammatory actions of GCs rely on GR-mediated inhibition of MAPKs and/or induction of DUSPs, the GC anti-inflammatory capacity is decreased or lost in conditions of excessive MAPK activation, contributing to disease susceptibility in tissue- and disease- specific manners. Here, we discuss potential strategies to modulate GC responsiveness, with the dual goal of overcoming GC resistance and minimizing the onset and severity of unwanted adverse effects while maintaining therapeutic potential

The mineralocorticoid receptor modulates timing and location of genomic binding by glucocorticoid receptor in response to synthetic glucocorticoids in keratinocytes

17 páginas, 6 figurasGlucocorticoids (GCs) exert potent antiproliferative and anti-inflammatory properties, explaining their therapeutic efficacy for skin diseases. GCs act by binding to the GC receptor (GR) and the mineralocorticoid receptor (MR), co-expressed in classical and non-classical targets including keratinocytes. Using knockout mice, we previously demonstrated that GR and MR exert essential nonoverlapping functions in skin homeostasis. These closely related receptors may homo- or heterodimerize to regulate transcription, and theoretically bind identical GC-response elements (GRE). We assessed the contribution of MR to GR genomic binding and the transcriptional response to the synthetic GC dexamethasone (Dex) using control (CO) and MR knockout (MREKO ) keratinocytes. GR chromatin immunoprecipitation (ChIP)-seq identified peaks common and unique to both genotypes upon Dex treatment (1 h). GREs, AP-1, TEAD, and p53 motifs were enriched in CO and MREKO peaks. However, GR genomic binding was 35% reduced in MREKO , with significantly decreased GRE enrichment, and reduced nuclear GR. Surface plasmon resonance determined steady state affinity constants, suggesting preferred dimer formation as MR-MR > GR-MR ~ GR-GR; however, kinetic studies demonstrated that GR-containing dimers had the longest lifetimes. Despite GR-binding differences, RNA-seq identified largely similar subsets of differentially expressed genes in both genotypes upon Dex treatment (3 h). However, time-course experiments showed gene-dependent differences in the magnitude of expression, which correlated with earlier and more pronounced GR binding to GRE sites unique to CO including near Nr3c1. Our data show that endogenous MR has an impact on the kinetics and differential genomic binding of GR, affecting the time-course, specificity, and magnitude of GC transcriptional responses in keratinocytes.This research is part of the grants PID2020-114652RB-I00 funded by MCIN/AEI/ 10.13039/501100011033 to PP, and PDC2021-121688-I00 to EE-P. The author's work was also supported by Inserm, Université Paris-Saclay. EC-Z was recipient of a postdoctoral fellowship from 15306860, 2023, 1, Downloaded from https://faseb.onlinelibrary.wiley.com/doi/10.1096/fj.202201199RR by Csic Organización Central Om (Oficialia Mayor) (Urici), Wiley Online Library on [25/01/2023]. See the Terms and Conditions (https://onlinelibrary.wiley.com/terms-and-conditions) on Wiley Online Library for rules of use; OA articles are governed by the applicable Creative Commons License | CARCELLER-ZAZO et al. 15 of 17 the Alfonso Martín Escudero Foundation (Spain); OP-A was funded by EDGJID/2021/098 (Generalitat Valenciana) and by ‘ESF Investing in your future.”. We thank NuRCaMeIN (SAF2017-90604-REDT) for support for dissemination. PP is a member of the Scientific Network on ´Strategies for therapeutic targeting of the Aldosterone-Mineralocorticoid Receptor signaling pathway (ADMIRE network) funded by the German Research Foundation (DFG-ID 470188766). This work has benefited from the facilities and expertize of the high-throughput sequencing core facility of I2BC (Centre de Recherche de Gif – http://www.i2bc. paris-saclay.fr/). This work was supported by the DIM Thérapie Génique Paris Ile-de-France Région, IBiSA, and the Labex GR-ExPeer reviewe

Keratinocyte-Targeted Overexpression of the Glucocorticoid Receptor Delays Cutaneous Wound Healing

Delayed wound healing is one of the most common secondary adverse effects associated to the therapeutic use of glucocorticoid (GC) analogs, which act through the ligand-dependent transcription factor GC-receptor (GR). GR function is exerted through DNA-binding-dependent and –independent mechanisms, classically referred to as transactivation (TA) and transrepression (TR). Currently both TA and TR are thought to contribute to the therapeutical effects mediated by GR; however their relative contribution to unwanted side effects such as delayed wound healing is unknown. We evaluated skin wound healing in transgenic mice with keratinocyte-restricted expression of either wild type GR or a mutant GR that is TA-defective but efficient in TR (K5-GR and K5-GR-TR mice, respectively). Our data show that at days (d) 4 and 8 following wounding, healing in K5-GR mice was delayed relative to WT, with reduced recruitment of granulocytes and macrophages and diminished TNF-α and IL-1β expression. TGF-β1 and Kgf expression was repressed in K5-GR skin whereas TGF-β3 was up-regulated. The re-epithelialization rate was reduced in K5-GR relative to WT, as was formation of granulation tissue. In contrast, K5-GR-TR mice showed delays in healing at d4 but re-established the skin breach at d8 concomitant with decreased repression of pro-inflammatory cytokines and growth factors relative to K5-GR mice. Keratinocytes from both transgenic mice closed in vitro wounds slower relative to WT, consistent with the in vivo defects in cell migration. Overall, the delay in the early stages of wound healing in both transgenic models is similar to that elicited by systemic treatment with dexamethasone. Wound responses in the transgenic keratinocytes correlated with reduced ERK activity both in vivo and in vitro. We conclude that the TR function of GR is sufficient for negatively regulating early stages of wound closure, while TA by GR is required for delaying later stages of healing

Explicit and implicit information needs of people with depression: a qualitative investigation of problems reported on an online depression support forum

<p>Abstract</p> <p>Background</p> <p>Health management is impeded when consumers do not possess adequate knowledge about their illness. At a public health level, consumer knowledge about depression is particularly important because depression is highly prevalent and causes substantial disability and burden. However, currently little is known about the information needs of people with depression. This study aimed to investigate the explicit and implicit information needs of users of an online depression support forum.</p> <p>Methods</p> <p>A sample of 2680 posts was systematically selected from three discussion forums on an online depression bulletin board (blueboard.anu.edu.au). Data were examined for evidence of requests for information (reflecting explicit needs) and reports of past or current problems (implicit needs). Thematic analysis was conducted using a data-driven inductive approach with the assistance of NVivo 7, and instances of questions and people reporting particular types of problems were recorded.</p> <p>Results</p> <p>A total of 134 participants with personal experience of depression contributed to the data analysed. Six broad themes represented participant queries and reported problems: Understanding depression; disclosure and stigma; medication; treatment and services; coping with depression; and comorbid health problems. A variety of specific needs were evident within these broad thematic areas. Some people (n = 46) expressed their information needs by asking direct questions (47 queries) but the majority of needs were expressed implicitly (351 problems) by the 134 participants. The most evident need for information related to coping with depression and its consequences, followed by topics associated with medication, treatment and services.</p> <p>Conclusions</p> <p>People with depression have substantial unmet information needs and require strategies to deal with the difficulties they face. They require access to high quality and relevant online resources and professionals; thus, there is a need to rectify current gaps in the provision of information and limitations of dissemination. Greater knowledge about depression and its treatment is also needed at the general community level.</p