Bitter Taste Receptors and Endocrine Disruptors: Cellular and Molecular Insights from an In Vitro Model of Human Granulosa Cells.

Endocrine disrupting chemicals (EDCs) are compounds that interfere with the synthesis, transport and binding action of hormones responsible for reproduction and homeostasis. Some EDCs compounds are activators of Taste bitter Receptors, a subclass of taste receptors expressed in many extraoral locations, including sperm and follicular somatic cells. This makes TAS2Rs attractive molecules to study and investigate to shed light on the effect of EDCs on female reproduction and fertility. This study aims to assess the effect of selected EDCs [namely Biochanin A (BCA), caffeine, Daidzein, Genistein and Isoflavone] on hGL5, an immortalized cell line exhibiting characteristics coherent with primary follicular granulosa cells. After demonstrating that this model expresses all the TAS2Rs (TAS2R3, TAS2R4, TAS2R14, TAS2R19, TAS2R43) specifically expressed by the primary human granulosa cells, we demonstrated that BCA and caffeine significantly affect mitochondrial footprint and intracellular lipid content, indicating their contribution in steroidogenesis. Our results showed that bitter taste receptors may be involved in steroidogenesis, thus suggesting an appealing mechanism by which these compounds affect the female reproductive system.

Expression of genes and localization of enzymes involved in polyunsaturated fatty acid synthesis in rabbit testis and epididymis.

The metabolism of polyunsaturated fatty acids (PUFAs) plays an important role in male reproduction. Linoleic and alpha-linolenic acids need to be provided in the diet and they are converted into long chain polyunsaturated fatty acids by steps of elongation and desaturation, exerted by elongases 2 (ELOVL2) and 5 (ELOVL5) and Δ5- (FADS1) and Δ6-desaturase (FADS2). This study aims to assess the gene expression and localization of enzymes involved in the synthesis of n-3 and n-6 long-chain PUFAs in control rabbits and those fed diets containing 10% extruded flaxseed. Enzyme and PUFA localization were assessed in the testes and epididymis by immunofluorescence. Testes showed high gene expression of FADS2, ELOVL2 and ELOVL5 and low expression of FADS1. Intermediate metabolites, enzymes and final products were differently found in Leydig, Sertoli and germinal cells. FADS2 was localized in interstitial cells and elongated spermatids; ELOVL5 in meiotic cells; FADS1 was evident in interstitial tissue, Sertoli cells and elongated spermatids; ELOVL2 in interstitial cells. Epididymal vesicles were positive for FADS1, ELOVL2 and ELOVL5 as well as docosahexaenoic, eicosapentaenoic, and arachidonic acids. This knowledge of fatty acids (FA) metabolism in spermatogenesis and the influence of diet on FA profile could help identify causes of male infertility, suggesting new personalized therapy.

Extracellular matrix remodeling and inflammatory pathway in human endometrium: insights from uterine leiomyomas.

OBJECTIVE: To compare the expression profiles of matrix metalloproteinases (MMPs) and their inhibitors (tissue inhibitors of matrix metalloproteinases, TIMPs) in the endometrium of women with and without type 3 leiomyomas and to understand their relationship with inflammatory status. DESIGN: Molecular and in silico studies. SETTING: University hospital. PATIENT(S): Patients with type 3 leiomyomas ranging from 3 to 10 cm in diameter (n = 18) and control age-matched women undergoing surgery for ovarian cysts (n = 18) who underwent endometrial biopsies. INTERVENTION(S): Endometrial biopsies. MAIN OUTCOME MEASURE(S): To evaluate the expression levels of MMPs and TIMPs in the endometrium, quantitative reverse transcriptase polymerase chain reaction and Western blot were performed. With the use of immunofluorescence analysis, the investigated proteins were localized in the tissues. The expression levels of inflammatory mediators such as IL-1ß, IL-6, IL-10, TGF, COX1, COX2, STAT3, and VEGF were evaluated by quantitative reverse transcriptase polymerase chain reaction, and their relationships were detected by the STRING approach. RESULT(S): The endometrium of women with type 3 leiomyomas exhibited differential expression of MMPs and TIMPs, particularly MMP2, MMP11, and MMP14, as well as different topographic distribution, suggesting that leiomyomas may influence the endometrial molecular profile. Significant decreases in IL-1ß, IL-6, and IL-10 expression, along with increases in COX1 and COX2, as well as VEGF, were highlighted. The STRING approach suggests that this altered gene expression profile may affect the Th17 cell differentiation pathway. CONCLUSION(S): The differential expression and localization of MMPs and TIMPs observed in women with type 3 leiomyomas, along with the reported derangement in the expression of key molecules involved in the inflammatory pathway, may contribute to changes in endometrial receptivity in these patients.

Centriolar defects, centrin 1 alterations, and FISH studies in human spermatozoa of a male partner of a couple that produces aneuploid embryos in natural and artificial fertilization.

PURPOSE: To study the potential paternal contribution to aneuploidies in the man of a couple who obtained trisomic embryos with natural and assisted fertilization. METHODS: Semen analysis, immunofluorescence for localization of tubulin and centrin 1, transmission electron microscopy (TEM), and fluorescence in situ hybridization (FISH) analysis for chromosomes 18 and 9 were performed. Sperm of fertile men were used as controls. RESULTS: The percentages of sperm motility and normal forms were decreased. The percentages of sperm with tail reduced in dimension, headless tails, coiled tails, and altered head-tail junction were significantly higher (P < 0.01) in the patient than in controls, whereas the percentage of sperm with a normal centrin 1 localization (two spots in the centriolar area) was significantly reduced (P < 0.01) in the patient. Immunofluorescence with anti-tubulin antibody showed that in most of the patient's sperm connecting pieces (83.00 ± 1.78%), two spots were present, indicating prominent proximal centriole/centriolar adjunct and evident distal centriole, whereas controls' sperm displayed a single spot, indicating the proximal centriole. The percentage of sperm with two spots was significantly higher (P < 0.01) in the patient than in controls. TEM analysis showed that centriolar adjuncts of the patient's sperm were significantly longer (721.80 ± 122.26 nm) than in controls' sperm (310.00 ± 64.11 nm; P < 0.001). The aneuploidy frequencies of the patient's sperm, detected by FISH analysis, were increased with respect to controls. CONCLUSION: A paternal contribution to sperm aneuploidies cannot be excluded since the patient's sperm showed altered morphology, immature centriolar adjunct, presence of evident distal centriole, scarce presence of centrin 1, and high aneuploidy frequency.

Retinoblastoma Is Characterized by a Cold, CD8+ Cell Poor, PD-L1- Microenvironment, Which Turns Into Hot, CD8+ Cell Rich, PD-L1+ After Chemotherapy.

Purpose: To investigate the impact of chemotherapy (CHT) on human retinoblastoma (RB) tumor microenvironment (TME). Cases and Methods: Ninety-four RBs were studied, including 44 primary RBs treated by upfront surgery (Group 1) and 50 primary RBs enucleated after CHT (CHT), either intra-arterial (IAC; Group 2, 33 cases) or systemic (S-CHT; Group 3, 17 cases). Conventional and multiplexed immunohistochemistry were performed to make quantitative comparisons among the three groups, for the following parameters: tumor-infiltrating inflammatory cells (TI-ICs); programmed cell death protein 1 (PD-1) positive TI-ICs; Ki67 proliferation index; gliosis; PD-1 ligand (PD-L1) protein expression; vessel number. We also correlated these TME factors with the presence of histological high-risk factors (HHRF+) and RB anaplasia grade (AG). Results: After CHT, a decrease in both RB burden and Ki67 positivity was observed. In parallel, most subsets of TI-ICs, PD-1+ TI-ICs, gliosis, and PD-L1 protein expression significantly increased (P < 0.001, P = 0.02, P < 0.001, respectively). Vessel number did not significantly vary. Age, HHRFs+ and AG were significantly different between primary and chemoreduced RBs (P < 0.001, P = 0.006, P = 0.001, respectively) and were correlated with most TME factors. Conclusions: CHT modulates host antitumor immunity by reorienting the RB TME from anergic into an active, CD8+, PD-L1+ hot state. Furthermore, some clinicopathological characteristics of RB correlate with several factors of TME. Our study adds data in favor of the possibility of a new therapeutic scenario in human RB.

Nitric Oxide/Cyclic GMP-Dependent Calcium Signalling Mediates IL-6- and TNF-α-Induced Expression of Glial Fibrillary Acid Protein.

Astrocyte activation is characterized by hypertrophy with increased glial fibrillary acidic protein (GFAP), whose expression may involve pro-inflammatory cytokines. In this study, the effects of pro-inflammatory IL-6 and TNF-α and anti-inflammatory cytokines IL-4 and IL-10 on nitric oxide (NO)/cyclic guanosine monophosphate (cGMP) signalling, intracellular calcium concentration ([Ca2+]i) and GFAP expression were investigated. In human glioblastoma astrocytoma U-373 MG cells, IL-6 and TNF-α, but not IL-4 or IL-10, increased iNOS, cGMP, [Ca2+]i and GFAP expression. The inhibitors of iNOS (1400 W), soluble guanylyl cyclase (ODQ) and IP3 receptors (ryanodine and 2-APB) reversed the increase in cGMP or [Ca2+]i, respectively, and prevented GFAP expression. In rat striatal slices, IL-6 and TNF-α, at variance with IL-4 and IL-10, promoted a concentration-dependent increase in Ca2+ efflux, an effect prevented by 1400 W, ODQ and RY/2APB. These data were confirmed by in vivo studies, where IL-6, TNF-α or the NO donor DETA/NO injected in the striatum of anaesthetised rats increased cGMP levels and increased GFAP expression. The present findings point to NO/cGMP-dependent calcium signalling as part of the mechanism mediating IL-6- and TNF-α-induced GFAP expression. As this process plays a fundamental role in driving neurotoxicity, targeting NO/cGMP-dependent calcium signalling may constitute a new approach for therapeutic interventions in neurological disorders.

KRIT1 as a possible new player in melanoma aggressiveness.

Krev interaction trapped protein 1 (KRIT1) is a scaffold protein known to form functional complexes with distinct proteins, including Malcavernin, PDCD10, Rap1 and others. It appears involved in several cellular signaling pathways and exerts a protective role against inflammation and oxidative stress. KRIT1 has been studied as a regulator of endothelial cell functions and represents a determinant in the pathogenesis of Cerebral Cavernous Malformation (CCM), a cerebrovascular disease characterized by the formation of clusters of abnormally dilated and leaky blood capillaries, which predispose to seizures, neurological deficits and intracerebral hemorrhage. Although KRIT1 is ubiquitously expressed, few studies have described its involvement in pathologies other than CCM including cancer. Cutaneous melanoma represents the most fatal skin cancer due to its high metastatic propensity. Despite the numerous efforts made to define the signaling pathways activated during melanoma progression, the molecular mechanisms at the basis of melanoma growth, phenotype plasticity and resistance to therapies are still under investigation.

Organoids of Human Endometrium: A Powerful In Vitro Model for the Endometrium-Embryo Cross-Talk at the Implantation Site.

Embryo implantation has been defined as the "black box" of human reproduction. Most of the knowledge on mechanisms underlining this process derives from animal models, but they cannot always be translated to humans. Therefore, the development of an in vitro/ex vivo model recapitulating as closely and precisely as possible the fundamental functional features of the human endometrial tissue is very much desirable. Here, we have validated endometrial organoids as a suitable 3D-model to studying epithelial endometrial interface for embryo implantation. Transmission and scanning electron microscopy analyses showed that organoids preserve the glandular organization and cell ultrastructural characteristics. They also retain the responsiveness to hormonal treatment specific to the corresponding phase of the menstrual cycle, mimicking the in vivo glandular-like aspect and functions. Noteworthy, organoids mirroring the early secretive phase show the development of pinopodes, large cytoplasmic apical protrusions of the epithelial cells, traditionally considered as reliable key features of the implantation window. Moreover, organoids express glycodelin A (GdA), a cycle-dependent marker of the endometrial receptivity, with its quantitative and qualitative features accounting well for the profile detected in the endometrium in vivo. Accordingly, organoids deriving from the eutopic endometrium of women with endometriosis show a GdA glycosylation pattern significantly different from healthy organoids, confirming our prior data on endometrial tissues. The present results strongly support the idea that organoids may closely recapitulate the molecular and functional characteristics of their cells/tissue of origin.

Correction: Cigarette Smoke Affects Keratinocytes SRB1 Expression and Localization via H2O2 Production and HNE Protein Adducts Formation.

[This corrects the article DOI: 10.1371/journal.pone.0033592.].

New insights into sperm with total globozoospermia: Increased fatty acid oxidation and centrin1 alteration.

Sperm morphology and lipid profile have a relevant role in male fertility. We explore the status of the sperm centriole, essential structure for human fertilization and the role of fatty acid oxidation in globozoospermia, a rare sperm pathology causing infertility. A case of globozoospermia was characterized by light and electron microscopy, sperm immunolocalization was performed for centrin1, 8-iso-PGF2α and peroxisome proliferator γ activated receptor gamma (PPARγ). In semen and sperm pellet, F2-isoprostanes (F2-IsoPs) levels were determined. Finally, the cytosolic phospholipase A2 (cPLA2) assessment was carried out in spermatozoa. The experiments were also performed in sperm from three fertile men. The results of electron microscopy analysis showed spermatozoa were round-headed without acrosome and with tail coiled around the nucleus characterized by immature chromatin. Centrin1 was located around the head in globozoospermic sperm, whereas, in sperm of controls, it appears as two spots. The 8-iso-PGF2α was detected around the head and in the cytoplasmic residue; PPARγ was mainly present in the cytoplasmic residue and under the head. The fluorescent signals for all molecules were different in the sperm of fertile men. F2-IsoPs levels, determined both in semen and sperm, were significantly increased (P < 0.05) and sperm cPLA2 was significantly decreased (P < 0.05) in the globozoospermic patients versus fertile subjects. In conclusion, sperm with globozoospermia showed an increased susceptibility to non-enzymatic fatty acid oxidation that could be, at least in part, responsible for fertilization failure in intracytoplasmic sperm injection. The opportunity to study a peculiar sperm pathology, as globozoospermia, could provide new insights in the relationship between lipid peroxidation and male infertility. Abbreviations: PPARγ: peroxisome proliferator γ activated receptor gamma; F2-IsoPs: F2-isoprostanes; cPLA2: cytosolic phospholipase A2; ICSI: Intracytoplasmic Sperm Injection; PLCζ: phospholipase C zeta; PUFAs: polyunsaturated fatty acid; AA: arachidonic acid; PLA2: phospholipase A2; SEM: scanning electron microscopy; TEM: transmission electron microscopy; AB: aniline blue; AO: acridine orange; FA: fatty acid; 8-iso-PGF2α: 8-iso-prostaglandin F2α; WHO: World Health Organization; DAPI: 4,6-Diamidino-2-phenylindole; PBS: phosphate buffered saline; GC/NICI-MS/MS: gas chromatography/negative-ion chemical ionization tandem mass spectrometry; BHT: butylated hydroxytoluene; PGF2α-d4: tetradeuterated derivative of Prostaglandin F2α; ELISA: enzyme-linked immunosorbent assay.

Defective spermatogenesis and testosterone levels in kinase suppressor of Ras1 (KSR1)-deficient mice.

The aim of this study was to clarify the role of the protein kinase suppressor of Ras1 (KSR1) in spermatogenesis. Spermatogenesis in ksr1 -/- mice was studied in testicular tissue and epididymal spermatozoa by light and transmission electron microscopy and by immunofluorescence using antibodies to ghrelin and 3ß-hydroxysteroid dehydrogenase (3ß-HSD). Blood testosterone levels were also assessed. ksr1 -/- mice showed reduced epididymal sperm concentration and motility as compared with wild- type (wt) mice. Testis tissue from ksr1 -/- mice revealed a prevalent spermatogenetic arrest at the spermatocyte stage; the interstitial tissue was hypertrophic and the cytoplasm of the Leydig cells was full of lipid droplets. Ghrelin signal was present in the seminiferous tubules and, particularly, in the interstitial tissue of wt mice; however, in ksr1 -/- mice ghrelin expression was very weak in both the interstitial tissue and tubules. On the contrary, the signal of 3ß-HSD was weak in the interstitial tissue of wt and strong in ksr1 -/- mice. Testosterone levels were significantly increased in the blood of ksr1 -/- mice (P <0.05) as compared with wt. The results obtained reveal the importance of the KSR scaffold proteins in the spermatogenetic process. The study of the molecular mechanisms associated with spermatogenetic defects in a mouse model is essential to understand the factors involved in human spermatogenesis.

Effect of Dietary n-3 Source on Rabbit Male Reproduction.

In the last two decades, the human sperm count linearly decreased in Western countries. Health problems, lifestyle, pollutants, and dietary behaviours are considered as the main risk factors, and the unbalance of dietary n-6/n-3 fatty acids is one of the most relevant. The aim of the present research is to study the effect of different dietary sources of n-3 polyunsaturated fatty acids (PUFA) on reproductive traits using rabbit buck as the animal model. Fifteen rabbit bucks were assigned to three experimental groups: the control group, the FLAX group fed 10% extruded flaxseed, and the FISH group fed 3.5% fish oil for 110 days (50-day adaptation and 60-day experimental periods). Semen samples were collected weekly, whereas blood was collected every two weeks for the analytical determination of semen traits, oxidative status, fatty acid profiles, isoprostanes, neuroprostanes, and the immunocytochemistry of docosahexaenoic acid (DHA) and eicosapentaenoic (EPA) acid. At the end of the trial, the rabbits were killed and the testes were removed and stored for the analysis of fatty acid profile and immunocytochemistry. Results showed that dietary administration of n-3 PUFA improved the track speed of the sperm and increased the n-3 long-chain PUFA mainly confined in the sperm tail. Seminal plasma increased the thiobarbituric reactive substances (TBARs) by three times in the groups fed supplemental n-3, whereas the F2-isoprotanes (F2-IsoPs) and F4-neuroprostanes (F4-NeuroPs) were lower and higher, respectively, in both supplemented groups than in the control. The testes and sperm showed a higher DHA and EPA distribution in rabbits from the n-3 supplemented groups compared with the control. In conclusion, supplemental dietary n-3 PUFA improved sperm motion traits and resulted in an enrichment of membrane fatty acid in the sperm and testes of the rabbits. However, such an increased amount of PUFA negatively affected the sperm oxidative status, which was mainly correlated with the generation of F4-NeuroPs with respect to F2-IsoPs. Accordingly, the latter cannot be considered a good marker of oxidation when diets rich in n-3 PUFA are provided.

SR-B1 involvement in keratinocytes in vitro wound closure.

Skin represents the most extended organ of human body, having as main function the protection of our body from outdoor stressors. Its protective ability is compromised when the skin is disrupted as a consequence of mechanical insults. For this purpose, cutaneous tissue is equipped with an efficient and fine mechanism involved in repairing the wounded area. Among the numerous players that take part in the wound healing process, SR-B1 has been recently shown to have a role in keratinocyte re-epithelialization. SR-B1 is a mediator of cholesterol uptake from HDLs, whereas it is implicated in other cellular processes such as vitamins absorption, vesicle trafficking or pathogen identification. The aim of this study was to investigate the mechanisms involved in SR-B1 role in skin wound closure. Our in vitro data demonstrated that SR-B1 influenced keratinocyte proliferation and migration through a downregulation of nuclear cyclin D1 levels and active MMP9 expression respectively possibly in an NF-kB-dependent mechanism. In addition, SR-B1 was also able to modulate keratinocyte morphology into a pro-migratory cytoskeleton rearrangement. The present in vitro study suggests a new role of SRB1 as a possible new key player in cutaneous wound healing mechanism.

Characterisation of three systematic sperm tail defects and their influence on ICSI outcome.

This study characterized three cases of systematic sperm tail defects using electron microscopy and immunolocalisation of centrin 1 and tubulin and explored their impact on ICSI outcome. Structural sperm tail defects of possible genetic origin were suspected as the eosin test revealed a sperm viability of >70% despite severe asthenozoospermia or the absence of motility. In Patient 1, 80%-85% of axoneme cross sections was incomplete. The fluorescent signal of tubulin was weak along the entire tail; the signal of centrin 1 was normal. After ICSI, a female healthy baby was born. Patient 2 showed spermatozoa with tails reduced in length at different levels, axonemal and periaxonemal alterations and fragility of head-tail junction. Centrin 1 was altered in 80% of sperm. After ICSI, no embryos were obtained. Patient 3 showed tails reduced in length at light and fluorescence microscopy; ultrastructural study revealed a condition of dysplasia of fibrous sheath with heterogeneity of tails' length. The signal for centrin 1 was altered in 50% of spermatozoa; two embryos were transferred without pregnancy. The correct diagnosis of sperm pathology is important in case of systematic sperm defects as it enables the clinician to improve patient's management and to provide an adequate genetic counselling.

Tropospheric ozone affects SRB1 levels via oxidative post-translational modifications in lung cells.

Exposure to air pollution is associated with increased respiratory morbidities and susceptibility to lung dysfunction. Ozone (O3) is commonly recognized as one of the most noxious air pollutant and has been associated with several lung pathologies. It has been demonstrated that decreased lung disorder severity and incidence are connected with the consumption of a diet rich in fruits and vegetables, suggesting that higher intake of dietary micronutrients and phytoactive compounds can be beneficial. However, dietary supplementation - i.e. vitamin E (α-tocopherol) or vitamin A - has not always been effective in improving pulmonary function. Recently, research on the role of nutritional antioxidants on human health has focused more on studying their uptake at the cellular level rather than their effective ability to scavenge reactvive oxygen species (ROS). The Scavenger Receptor B1 (SRB1) has been shown to play a prominent role in the uptake, delivery and regulation of vitamin E in the lung. Given the importance of SRB1 in maintaining lung tissue in a healthy condition, we hypothesize that its expression could be modulated by pollution exposure, which thus could indirectly affect the uptake and/or delivery of lipophilic substances, such as vitamin E. To characterize the molecular mechanism involved in the redox modulation of SRB1, its cellular levels were assessed in human alveolar epithelial cells after O3 exposure. The results demonstrated that O3 induced the loss of SRB1 protein levels. This decline seems to be driven by hydrogen peroxide (H2O2) as a consequence of an increased activation of cellular NADPH oxidase (NOX), as demonstrated by the use of NOX inhibitors or catalase that reversed this effect. Furthermore, O3 caused the formation of SRB1-aldheyde adducts (4-hydroxy-2-nonenal) and the consequent increase of its ubiquitination, a mechanism that could account for SRB1 protein loss.

Dysregulation of GdA Expression in Endometrium of Women With Endometriosis: Implication for Endometrial Receptivity.

Glycodelin-A (GdA) has been proposed to represent a potential biomarker of endometrial function, but little is known about its expression during the different phases of the menstrual cycle and under pathological conditions. In the light of its potential importance also in embryo implantation, we aimed to evaluate the expression profile of GdA as well as the presence of different glycosylated glycoforms and the immunolocalization in endometrial tissue from women with endometriosis and in women with proven fertility, at different times during the menstrual cycle. Our results showed that GdA is synthesized by endometrial epithelial and stromal cells, both in healthy endometrium and eutopic endometrium from women with endometriosis, with a profile including several glycosylated glycoforms, differentially expressed in each phase of the menstrual cycle. During the secretory phase, a significant increase in GdA protein expression, with a different glycoforms profile, was observed in endometriotic eutopic endometrium. Protein localization in eutopic endometrial tissue resulted significantly different in comparison with endometrium from women with proven fertility. This study indicate that GdA is a complex glycoprotein including up to 6 different glycoforms specifically expressed during the different phase of the menstrual cycle; in pathologic conditions such as endometriosis, the expression profile is altered possibly related to the impaired endometrial receptivity.

Keratinocytes oxidative damage mechanisms related to airbone particle matter exposure.

Epidemiological evidences have correlated airbone particulate matter (PM) to adverse health effects, mainly linking to pulmonary and cardiovascular disease. Nevertheless, only recently, some studies reported detrimental effects of PM on other organs such as skin. In a recent work, we have reported increased oxidative and inflammatory responses in Reconstituted Human Epidermis (RHE) exposed to ambient particles (CAPs) and we also demonstrated the ability of CAPs to penetrate the skin tissue. The present study was aimed to better understand the cellular mechanisms beyond the oxidative changes induced by CAPs (5-10-25µg/mL) in human immortalized keratinocytes (HaCaT). After 24h of treatment, CAPs were able to enter the cells leading to a decrease in viability, increased levels of 4-hydroxinonenal products (4-HNE) and IL-1α release. Overall these data, suggest lipid and protein oxidative damage, as well as an increase of inflammatory response after being challenged with CAPs. In addition, 3h after CAPs exposure we found a significant increase in NF-kB and Nrf2 translocation into the nucleus. In contrast, no differences in gene expression and enzymatic activity of Nrf2 target genes were detected. This last finding could be explained by the ability of CAPs to possibly alter the binding of Nrf2 to the ARE DNA sequence.

Modulation of cutaneous scavenger receptor B1 levels by exogenous stressors impairs "in vitro" wound closure.

Scavenger receptor B1 (SR-B1) is a trans-membrane protein, involved in tissue reverse cholesterol transport. Several studies have demonstrated that SR-B1 is also implicated in other physiological processes, such as bacteria and apoptotic cells recognition and regulation of intracellular tocopherol and carotenoids levels. Among the tissues where it is localized, SR-B1 has been shown to be significantly expressed in human epidermis. Our group has demonstrated that SR-B1 levels are down-regulated in human cultured keratinocytes by environmental stressors, such as cigarette smoke, via cellular redox imbalance. Our present study aimed to investigate whether such down-regulation was confirmed in a 3D skin model and under other environmental challengers such as particulate matter and ozone. We also investigated the association between oxidation-induced SR-B1 modulation and impaired wound closure. The data obtained showed that not only cigarette, but also the other environmental stressors reduced SR-B1 expression in epidermal cutaneous tissues and that this effect might be involved in impaired wound healing.