The Thyroid Hormone Receptors Modulate the Skin Response to Retinoids

[Background]: Retinoids play an important role in skin homeostasis and when administered topically cause skin hyperplasia, abnormal epidermal differentiation and inflammation. Thyroidal status in humans also influences skin morphology and function and we have recently shown that the thyroid hormone receptors (TRs) are required for a normal proliferative response to 12-O-tetradecanolyphorbol-13-acetate (TPA) in mice. [Methodology/Principal Findings]: We have compared the epidermal response of mice lacking the thyroid hormone receptor binding isoforms TRα1 and TRβ to retinoids and TPA. Reduced hyperplasia and a decreased number of proliferating cells in the basal layer in response to 9-cis-RA and TPA were found in the epidermis of TR-deficient mice. Nuclear levels of proteins important for cell proliferation were altered, and expression of keratins 5 and 6 was also reduced, concomitantly with the decreased number of epidermal cell layers. In control mice the retinoid (but not TPA) induced parakeratosis and diminished expression of keratin 10 and loricrin, markers of early and terminal epidermal differentiation, respectively. This reduction was more accentuated in the TR deficient animals, whereas they did not present parakeratosis. Therefore, TRs modulate both the proliferative response to retinoids and their inhibitory effects on skin differentiation. Reduced proliferation, which was reversed upon thyroxine treatment, was also found in hypothyroid mice, demonstrating that thyroid hormone binding to TRs is required for the normal response to retinoids. In addition, the mRNA levels of the pro-inflammatory cytokines TNFα and IL-6 and the chemotactic proteins S1008A and S1008B were significantly elevated in the skin of TR knock-out mice after TPA or 9-cis-RA treatment and immune cell infiltration was also enhanced. [Conclusions/significance]: Since retinoids are commonly used for the treatment of skin disorders, these results demonstrating that TRs regulate skin proliferation, differentiation and inflammation in response to these compounds could have not only physiological but also therapeutic implications.This work was supported by grants BFU2007-62402 and SAF2008-00121 from Ministerio de Ciencia e Innovación, RD06/0020/0036 and RD06/0020/0029 from the Fondo de Investigaciones Sanitarias and by the European Grant CRESCENDO (FP-018652).Peer reviewe

UroMark-a urinary biomarker assay for the detection of bladder cancer.

BACKGROUND: Bladder cancer (BC) is one of the most common cancers in the western world and ranks as the most expensive to manage, due to the need for cystoscopic examination. BC shows frequent changes in DNA methylation, and several studies have shown the potential utility of urinary biomarkers by detecting epigenetic alterations in voided urine. The aim of this study is to develop a targeted bisulfite next-generation sequencing assay to diagnose BC from urine with high sensitivity and specificity. RESULTS: We defined a 150 CpG loci biomarker panel from a cohort of 86 muscle-invasive bladder cancers and 30 normal urothelium. Based on this panel, we developed the UroMark assay, a next-generation bisulphite sequencing assay and analysis pipeline for the detection of bladder cancer from urinary sediment DNA. The 150 loci UroMark assay was validated in an independent cohort (n = 274, non-cancer (n = 167) and bladder cancer (n = 107)) voided urine samples with an AUC of 97%. The UroMark classifier sensitivity of 98%, specificity of 97% and NPV of 97% for the detection of primary BC was compared to non-BC urine. CONCLUSIONS: Epigenetic urinary biomarkers for detection of BC have the potential to revolutionise the management of this disease. In this proof of concept study, we show the development and utility of a novel high-throughput, next-generation sequencing-based biomarker for the detection of BC-specific epigenetic alterations in urine

The Thyroid Hormone Receptors Modulate the Skin Response to Retinoids

[Background]: Retinoids play an important role in skin homeostasis and when administered topically cause skin hyperplasia, abnormal epidermal differentiation and inflammation. Thyroidal status in humans also influences skin morphology and function and we have recently shown that the thyroid hormone receptors (TRs) are required for a normal proliferative response to 12-O-tetradecanolyphorbol-13-acetate (TPA) in mice. [Methodology/Principal Findings]: We have compared the epidermal response of mice lacking the thyroid hormone receptor binding isoforms TRα1 and TRβ to retinoids and TPA. Reduced hyperplasia and a decreased number of proliferating cells in the basal layer in response to 9-cis-RA and TPA were found in the epidermis of TR-deficient mice. Nuclear levels of proteins important for cell proliferation were altered, and expression of keratins 5 and 6 was also reduced, concomitantly with the decreased number of epidermal cell layers. In control mice the retinoid (but not TPA) induced parakeratosis and diminished expression of keratin 10 and loricrin, markers of early and terminal epidermal differentiation, respectively. This reduction was more accentuated in the TR deficient animals, whereas they did not present parakeratosis. Therefore, TRs modulate both the proliferative response to retinoids and their inhibitory effects on skin differentiation. Reduced proliferation, which was reversed upon thyroxine treatment, was also found in hypothyroid mice, demonstrating that thyroid hormone binding to TRs is required for the normal response to retinoids. In addition, the mRNA levels of the pro-inflammatory cytokines TNFα and IL-6 and the chemotactic proteins S1008A and S1008B were significantly elevated in the skin of TR knock-out mice after TPA or 9-cis-RA treatment and immune cell infiltration was also enhanced. [Conclusions/significance]: Since retinoids are commonly used for the treatment of skin disorders, these results demonstrating that TRs regulate skin proliferation, differentiation and inflammation in response to these compounds could have not only physiological but also therapeutic implications.This work was supported by grants BFU2007-62402 and SAF2008-00121 from Ministerio de Ciencia e Innovación, RD06/0020/0036 and RD06/0020/0029 from the Fondo de Investigaciones Sanitarias and by the European Grant CRESCENDO (FP-018652).Peer reviewe

Skin tumors Rb(eing) uncovered

The Rb1 gene was the first bona fide tumor suppressor identified and cloned more than 25 years ago. Since then, a plethora of studies have revealed the functions of pRb and the existence of a sophisticated and strictly regulated pathway that modulates such functional roles. An emerging paradox affecting Rb1 in cancer connects the relatively low number of mutations affecting Rb1 gene in specific human tumors, compared with the widely functional inactivation of pRb in most, if not in all, human cancers. The existence of a retinoblastoma family of proteins pRb, p107 and p130 and their potential unique and overlapping functions as master regulators of cell cycle progression and transcriptional modulation by similar processes, may provide potential clues to explain such conundrum. Here, we will review the development of different genetically engineered mouse models, in particular those affecting stratified epithelia, and how they have offered new avenues to understand the roles of the Rb family members and their targets in the context of tumor development and progression

Both TRα and TRβ are expressed in the mouse skin.

<p>Double immunofluorescence images of expression of keratin 14 (K14, green) with TRα or TRβ (red). Images were obtained from the interfollicular epidermis (IFE) and the hair follicles (HF) of wild-type mice. The slides were counterstained with DAPI (blue) and the merged images are shown. Bars: 50 µM.</p

Migration in vitro is enhanced in keratinocytes obtained from TRs deficient mice.

<p>(<b>A</b>) Representative images of scratch wound assays in primary cultures of newborn keratinocytes from Wt and TR KO mice. Confluent cultures were treated with mitomycin C (MMC) for 2 h before wounds were made. The right panel illustrates the rate of wound closure obtained in untreated and MMC treated cultures in both genotypes. (<b>B</b>) Representative images of dorsal skin explants from newborn Wt and TR KO mice treated with MMC and then incubated during 6 days in the presence and absence (Cont.) of EGF. In the right panel the number and size of keratinocyte foci migrating out of the explants in the presence and absence of MMC and EGF were quantitated. Data are shown as mean values ± SD, and asterisks denote statistically significant differences of Wt vs KO cultures. *, P<0.05; **, P<0.01; ***, P<0.001.</p

Deletion of both TRα1 and TRβ is required to impair follicular proliferation and the anagen response to depilation.

<p>(<b>A</b>) Percentage of follicles in anagen growing phase and (<b>B</b>) Follicular BrdU incorporation, 5 days after exhaustive depilation. Experiments were assed in Wt animals, animals lacking both TRα1 and TRβ (KO), and in the individual KOs for TRα1 and TRβ (KOα1 and KOβ, respectively). Data are shown as mean values ± SE and the asterisk denotes a statistically significant difference (P<0.05) of KO vs Wt mice. Defective follicular proliferation and anagen response to depilation in hypothyroid mice. The percentage of hair follicles in anagen and BrdU incorporation in the follicular keratinocytes was quantified 5 days after depilation in Wt control mice (Ct), in mice made hypothyroid by treatment with antithyroidal drugs for 4 months (hT) and in a group of animals receiving the anti-thyroidal drugs plus thyroxine (hT+T4). A group of age-matched double KO mice were also used. Data are represented as the % of positive BrdU cells vs. total hair follicle cells. Data are shown as mean values ± SE, and asterisks denote statistically significant differences vs Ct mice. *, P<0.05; **, P<0.01.</p

Increased expression of proinflammatory and chemotactic molecules in skins of TR KO mice.

<p>Relative mRNA levels of TNFα, IL-6, S100A8 and S100A9 in wild-type and TR KO mice treated with vehicle, 9-cis-RA or TPA. Values representing expression levels of vehicle-treated wil-type mice were set to 1, and fold induction is represented relative to this basal level.</p