Role of AHR Ligands in Skin Homeostasis and Cutaneous Inflammation.

Aryl hydrocarbon receptor (AHR) is an important regulator of skin barrier function. It also controls immune-mediated skin responses. The AHR modulates various physiological functions by acting as a sensor that mediates environment-cell interactions, particularly during immune and inflammatory responses. Diverse experimental systems have been used to assess the AHR's role in skin inflammation, including in vitro assays of keratinocyte stimulation and murine models of psoriasis and atopic dermatitis. Similar approaches have addressed the role of AHR ligands, e.g., TCDD, FICZ, and microbiota-derived metabolites, in skin homeostasis and pathology. Tapinarof is a novel AHR-modulating agent that inhibits skin inflammation and enhances skin barrier function. The topical application of tapinarof is being evaluated in clinical trials to treat psoriasis and atopic dermatitis. In the present review, we summarize the effects of natural and synthetic AHR ligands in keratinocytes and inflammatory cells, and their relevance in normal skin homeostasis and cutaneous inflammatory diseases.

Electrophilic nitro-fatty acids suppress psoriasiform dermatitis: STAT3 inhibition as a contributory mechanism.

Psoriasis is a chronic inflammatory skin disease with no cure. Although the origin of psoriasis and its underlying pathophysiology remain incompletely understood, inflammation is a central mediator of disease progression. In this regard, electrophilic nitro-fatty acids (NO2-FAs) exert potent anti-inflammatory effects in several in vivo murine models of inflammatory diseases, such as chronic kidney disease and cardiovascular disease. To examine the therapeutic potential of NO2-FAs on psoriasiform dermatitis, we employed multiple murine models of psoriasis. Our studies demonstrate that oral treatment with nitro oleic acid (OA-NO2) has both preventative and therapeutic effects on psoriasiform inflammation. In line with this finding, oral OA-NO2 downregulated the production of inflammatory cytokines in the skin. In vitro experiments demonstrate that OA-NO2 decreased both basal IL-6 levels and IL-17A-induced expression of IL-6 in human dermal fibroblasts through the inhibition of NF-κB phosphorylation. Importantly, OA-NO2 diminished STAT3 phosphorylation and nuclear translocation via nitroalkylation of STAT3, which inhibited keratinocyte proliferation. Overall, our results affirm the critical role of both NF-κB and STAT3 in the incitement of psoriasiform dermatitis and highlight the pharmacologic potential of small molecule nitroalkenes for the treatment of cutaneous inflammatory diseases, such as psoriasis.

The Translational Relevance of Human Circulating Memory Cutaneous Lymphocyte-Associated Antigen Positive T Cells in Inflammatory Skin Disorders.

Circulating memory T cells are heterogeneous in their tissue tropism. The skin-seeking T cell subset expresses the cutaneous lymphocyte-associated antigen (CLA) on their surface. CLA+ memory T cells not only migrate from blood to skin but also recirculate between blood and skin. Studying CLA+ memory T cells in cutaneous diseases has allowed a better understanding of immune-inflammatory mechanisms that take place. The analysis of the phenotypical features of these cells, their antigen specificity, cytokine production profile, and changes in relationship to clinical status and therapies among other characteristics have led to the concept that they constitute peripheral cellular biomarkers in T cell-mediated cutaneous conditions. CLA+ memory T cells are of relevance in the pathogenesis of several cutaneous diseases, such as psoriasis (PSO), atopic dermatitis, vitiligo, and drug-induced allergic reactions, to name a few. The interaction of circulating CLA+ T cells with skin-resident cells has been investigated in different ex vivo coculture models made out of clinical samples. Interestingly, microbes that are present in the skin or related with human skin diseases are preferentially recognized by CLA+ T cells. Thus, the interaction of Streptococcus pyogenes with CLA+ T cells in PSO is providing novel concepts that help to understand disease immunopathogenesis. The goal of this review is to present latest results in the field of CLA+ T cells in T cell-mediated inflammatory skin diseases and their translational relevance for human immunodermatology.

Vitamin D3 ameliorates nitrogen mustard-induced cutaneous inflammation by inactivating the NLRP3 inflammasome through the SIRT3-SOD2-mtROS signaling pathway.

Nitrogen mustard (NM) causes severe skin injury with an obvious inflammatory response, which is lack of effective and targeted therapies. Vitamin D3 (VD3) has excellent anti-inflammatory properties and is considered as a potential candidate for the treatment of NM-induced dermal toxicity; however, the underlying mechanisms are currently unclear. Cyclooxygenase-2 (COX2; a widely used marker of skin inflammation) plays a key role in NM-induced cutaneous inflammation. Herein, we initially confirmed that NM markedly promoted COX2 expression in vitro and in vivo. NM also increased NOD-like receptor family pyrin domain containing 3 (NLRP3) expression, caspase-1 activity, and interleukin-1ß (IL-1ß) release. Notably, treatment with a caspase-1 inhibitor (zYVAD-fmk), NLRP3 inhibitor (MCC950), and NLRP3 or caspase-1 siRNA attenuated NM-induced NLRP3 inflammasome activation, with subsequent suppression of COX2 expression and IL-1ß release in keratinocytes. Meanwhile, NM increased mitochondrial reactive oxygen species (mtROS) and decreased manganese superoxide dismutase 2 (SOD2) and sirtuin 3 (SIRT3) activities. Mito-TEMPO (a mtROS scavenger) ameliorated NM-caused NLRP3 inflammasome activation in keratinocytes. Moreover, VD3 improved SIRT3 and SOD2 activities, decreased mtROS contents, inactivated the NLRP3 inflammasome, and attenuated cutaneous inflammation induced by NM in vitro and in vivo. The beneficial activity of VD3 against NM-triggered cutaneous inflammation was enhanced by the inhibitors of IL-1, mtROS, NLRP3, caspase-1, and NLRP3 or caspase-1 siRNAs, which was abolished in SIRT3 inhibitor or SIRT3 siRNA-treated keratinocytes and skins from SIRT3-/- mice. In conclusion, VD3 ameliorated NM-induced cutaneous inflammation by inactivating the NLRP3 inflammasome, which was partially mediated through the SIRT3-SOD2-mtROS signaling pathway.

Dysregulated skin barrier function in Tmem79 mutant mice promotes IL-17A-dependent spontaneous skin and lung inflammation.

BACKGROUND: Atopic dermatitis (AD) is associated with a dysregulation of the skin barrier and may predispose to the development of secondary allergic conditions, such as asthma. Tmem79ma/ma mice harbor a mutation in the gene encoding Transmembrane Protein 79 (or Mattrin), which has previously been associated with AD. As a result of the Tmem79 gene mutation, these mice have a defective skin barrier and develop spontaneous skin inflammation. In this study, Tmem79ma/ma mice were assessed for the underlying immunological response in the development of spontaneous skin and lung inflammation. METHODS: Development of spontaneous skin and lung inflammation in Tmem79ma/ma mice was analyzed. We further investigated susceptibility to cutaneous Staphylococcus aureus infection. Tmem79ma/ma were crossed to IL-17A-deficient mice to address the contribution of IL-17A to spontaneous skin and lung disease. RESULTS: Tmem79ma/ma mice developed IL-17A-dependent spontaneous AD-like inflammation and were refractory to S aureus infection. Mutant mice progressed to airway inflammation subsequent to the occurrence of dermatitis. The progression from skin to lung disease is dependent on adaptive immunity and is facilitated by cutaneous expansion of Th17 and TCRγδ T cells. CONCLUSION: Mice lacking Tmem79/Mattrin expression have a defective skin barrier. In adulthood, these mice develop dermatitis with secondary progression to lung inflammation. The development of skin and lung inflammation is IL-17A-dependent and mediated by TCRγδ T cells.

Hydrogel containing silibinin nanocapsules presents effective anti-inflammatory action in a model of irritant contact dermatitis in mice.

The current study developed an innovative Pemulen® TR2 hydrogel containing silibinin-loaded pomegranate oil-based nanocapsules (HP-NC SB) intending cutaneous application. The formulation anti-inflammatory activity in an in vivo model and biometric studies on the skin of healthy volunteers were also performed. The nanocapsules were prepared using the interfacial deposition of preformed polymer technique and the hydrogels were obtained by thickening of nanocapsules suspension with Pemulen® TR2. Formulations with free compound, vehicle and blank nanocapsules were also produced. The hydrogels were evaluated concerning pH, silibinin content, particle size, spreadability profile, rheology, in vitro drug release, cutaneous permeation, bioadhesive potential and cutaneous biometry evaluation. Furthermore, a model of contact dermatitis croton oil-induced in mice was performed to evaluate the hydrogels anti-inflammatory potential. The formulations presented adequate characteristics for skin administration: particle within nanometric size, pH values in the acid range, silibinin content close theoretical values (1 mg/g) and non-Newtonian pseudoplastic behavior. Nano-based hydrogels showed high bioadhesive properties, increased silibinin in vitro release profile and its retention in the stratum corneum. The best anti-inflammatory effect was exhibited by HP-NC SB, which reduced both ear edema and inflammatory cells infiltration in comparison to the induced group. Furthermore, cutaneous biometric evaluation showed that formulations containing free or nanoencapsulated silibinin caused no modification in normal skin conditions (pH, tissue hydration, transepidermal water loss and erythema). In summary, the results demonstrated that the Pemulen® TR2 hydrogel containing NC SB was successfully developed, indicating its potential as an alternative treatment for irritant contact dermatitis.

[Contiguous cutaneous inflammation secondary to an aspergillus sinusitis]. / Inflammation cutanée de contiguïté secondaire à une sinusite aspergillaire.

BACKGROUND: Contiguous skin inflammation is a poorly described entity. It constitutes a cutaneous manifestation of an underlying ongoing process (infectious, inflammatory or neoplastic). Sinusitis is a known cause. PATIENTS AND METHODS: We report the case of a 70-year-old patient consulting for an ongoing centrofacial inflammatory plaque. Cutaneous biopsy revealed a polymorphic inflammatory infiltrate, and cutaneous microbiological specimens were negative. A facial CT-scan showed left maxillary sinusitis. Intra-sinus samples obtained at surgery showed aspergillus. Voriconazole combined with maxillary sinus surgery resulted in healing of the facial plaque. DISCUSSION: There have been only two published cases of contiguous skin inflammation related to sinusitis but no reported cases caused by aspergillus sinusitis. Herein we report the third case of contiguous skin inflammation associated with sinusitis, which is also the first related to aspergillus sinusitis.

Urban particulate matter in air pollution penetrates into the barrier-disrupted skin and produces ROS-dependent cutaneous inflammatory response in vivo.

BACKGROUND: Particulate matter (PM) is an integral part of air pollution, which is a mixture of particles suspended in the air. Recently, it has been reported that PM is associated with increased risks of skin diseases, especially atopic dermatitis in children. However, it is unclear if PM directly goes into the skin and what mechanisms are involved in response to PM. OBJECTIVE: To see whether PM could penetrate into the barrier-disrupted skin, produce reactive oxygen species (ROS), and elicit an inflammatory response. METHODS: We collected PMs during a winter in Seoul and used cultured keratinocytes for in vitro study and tape-stripped BALB/c mice for in vivo study. RESULTS: Keratinocyte cytotoxicity increased in a dose-dependent manner by PM treatment. IL-8 and MMP-1 mRNA expression and protein levels were significantly increased compared to control by qPCR and ELISA, respectively. Cellular ROS production was increased by PM treatment, and antioxidant N-acetyl cysteine pretreatment prevented induction of inflammatory cytokines IL-8 and MMP-1. In PM-treated keratinocytes, electron-dense subcellular particles were observed by transmission electron microscopy. PM was observed inside hair follicles in both intact and barrier-disrupted skin in vivo. Additionally, intercellular penetration of PM was seen in the barrier-disrupted skin. Repeated PM application induced epidermal thickening and dermal inflammation with neutrophil infiltration. Finally, N-acetyl cysteine could ameliorate skin inflammation induced by PM application. CONCLUSION: PM penetrates into the barrier-disrupted skin, causing inflammation, demonstrating detrimental effects in the skin.

Anti-inflammatory effect of external use of escin on cutaneous inflammation: possible involvement of glucocorticoids receptor.

Escin, as an internally applied anti-inflammatory agent, has been widely used in the treatment of inflammation and edema resulting from trauma or operation in the clinic. However, the effect of its external use on cutaneous inflammation and edema remains unexplored. In the present study, the anti-inflammatory and anti-edematous effects of external use of escin were studied in carrageenan-induced paw edema and histamine-induced capillary permeability in rats, paraxylene-induced ear swelling in mice, and cotton pellet-induced granuloma in rats. Effects of external use of escin gel on prostaglandin E2 (PGE2), tumor necrosis factor-α (TNF-α), and interleukin-1ß (IL-1ß) were determined by ELISA. The anti-inflammatory mechanism was explored by detecting the expression of glucocorticoid receptor (GR) with Western blotting and Real-time PCR analyses, with further exploration of nuclear factor-κB (NF-κB), p38 mitogen-activated protein kinase (P38MAPK) and activator protein-1 (AP-1) expressions. We demonstrated that external use of escin showed significant anti-inflammatory effects on acute and chronic inflammation in different animal models and its anti-inflammatory effects might be related to down-regulation of PGE2, TNF-α, and IL-1ß. The results also showed that escin exerted its anti-inflammatory effects by promoting the expression of GR, with the possible mechanism being inhibition of the expressions of GR-related signaling molecules such as NF-κB and AP-1.

Effects of blue light on inflammation and skin barrier recovery following acute perturbation. Pilot study results in healthy human subjects.

BACKGROUND/PURPOSE: While growing evidence supports the therapeutic effect of 453 nm blue light in chronic inflammatory skin diseases, data on its effects on acutely perturbed human skin are scarce. In this study, we investigated the impact of 453 nm narrow-band LED light on healthy skin following acute perturbation. METHODS: Tape stripping and histamine iontophoresis were performed on the forearm of 22 healthy volunteers on 2 consecutive weeks. In 1 week, challenges were followed by irradiation for 30 minutes. In the other week (control), no light was administered. Reactions were evaluated up to 72 hours thereafter by transepidermal water loss (TEWL), diffuse reflectance spectroscopy, and skin surface biomarkers. RESULTS: Skin barrier disruption resulted in upregulation of IL-1α at 24 hours after tape stripping (P = .029). In contrast, irradiation abrogated this effect (P > .05). Irradiation also resulted in higher TEWL at 24 hours and in higher b* value at 72 hours after tape stripping compared to the control (P = .034 and P = .018, respectively). At 30 minutes following histamine iontophoresis and irradiation, a trend toward a higher a* value compared to the control was observed (P = .051). CONCLUSION: We provide the first in vivo evidence that blue light at 453 nm exerts biological effects on acutely perturbed healthy human skin.

Anti-inflammatory effect of external use of escin on cutaneous inflammation: possible involvement of glucocorticoids receptor / 中国天然药物

Escin, as an internally applied anti-inflammatory agent, has been widely used in the treatment of inflammation and edema resulting from trauma or operation in the clinic. However, the effect of its external use on cutaneous inflammation and edema remains unexplored. In the present study, the anti-inflammatory and anti-edematous effects of external use of escin were studied in carrageenan-induced paw edema and histamine-induced capillary permeability in rats, paraxylene-induced ear swelling in mice, and cotton pellet-induced granuloma in rats. Effects of external use of escin gel on prostaglandin E2 (PGE2), tumor necrosis factor-α (TNF-α), and interleukin-1β (IL-1β) were determined by ELISA. The anti-inflammatory mechanism was explored by detecting the expression of glucocorticoid receptor (GR) with Western blotting and Real-time PCR analyses, with further exploration of nuclear factor-κB (NF-κB), p38 mitogen-activated protein kinase (P38MAPK) and activator protein-1 (AP-1) expressions. We demonstrated that external use of escin showed significant anti-inflammatory effects on acute and chronic inflammation in different animal models and its anti-inflammatory effects might be related to down-regulation of PGE2, TNF-α, and IL-1β. The results also showed that escin exerted its anti-inflammatory effects by promoting the expression of GR, with the possible mechanism being inhibition of the expressions of GR-related signaling molecules such as NF-κB and AP-1.

Anti-inflammatory effect of external use of escin on cutaneous inflammation: possible involvement of glucocorticoids receptor / 中国天然药物

Escin, as an internally applied anti-inflammatory agent, has been widely used in the treatment of inflammation and edema resulting from trauma or operation in the clinic. However, the effect of its external use on cutaneous inflammation and edema remains unexplored. In the present study, the anti-inflammatory and anti-edematous effects of external use of escin were studied in carrageenan-induced paw edema and histamine-induced capillary permeability in rats, paraxylene-induced ear swelling in mice, and cotton pellet-induced granuloma in rats. Effects of external use of escin gel on prostaglandin E2 (PGE2), tumor necrosis factor-α (TNF-α), and interleukin-1β (IL-1β) were determined by ELISA. The anti-inflammatory mechanism was explored by detecting the expression of glucocorticoid receptor (GR) with Western blotting and Real-time PCR analyses, with further exploration of nuclear factor-κB (NF-κB), p38 mitogen-activated protein kinase (P38MAPK) and activator protein-1 (AP-1) expressions. We demonstrated that external use of escin showed significant anti-inflammatory effects on acute and chronic inflammation in different animal models and its anti-inflammatory effects might be related to down-regulation of PGE2, TNF-α, and IL-1β. The results also showed that escin exerted its anti-inflammatory effects by promoting the expression of GR, with the possible mechanism being inhibition of the expressions of GR-related signaling molecules such as NF-κB and AP-1.

Histamine Iontophoresis as in vivo Model to Study Human Skin Inflammation with Minimal Barrier Impairment: Pilot Study Results of Application of the Model to a Sensitive Skin Panel.

BACKGROUND/AIMS: Histamine iontophoresis is known to elicit itch and a wheal-and-flare reaction; however, its impact on the skin barrier and underlying compartments has not been thoroughly evaluated yet. The primary objective of this study was to characterize that using immunohistochemistry, biophysical measurements, and image analysis, and secondly, to explore whether skin reactions to this model differ in sensitive skin (SS). METHODS: Eighteen healthy subjects, n = 9 with SS and n = 9 with non-sensitive skin (NSS), were included based on a perception-based questionnaire. Histamine iontophoresis was performed on the buttock, and skin reactions were evaluated up to 72 h after stimulation. RESULTS: The wheal-and-flare peaked at 30 min; after 8 h, no clinical signs were visible. No signs of disruption of the stratum corneum, as well as no increase in the number of Ki67-positive cells emerged, whereas fewer tryptase-positive mast cells and increased epidermal thickness were observed at 1 and 72 h, respectively. SS subjects showed higher perception of itch compared to NSS subjects. CONCLUSION: Histamine iontophoresis is a well-standardized in vivo model to quantitatively study the early stages of cutaneous inflammation with minimal impact on the skin barrier. In line with previous studies, it highlighted increased sensory perceptions in SS.

Cutaneous inflammation regulates THIK1 expression in small C-like nociceptor dorsal root ganglion neurons.

Tandem pore-domain Halothane Inhibited K+ channel (THIK1) is a two-pore-domain potassium channel (K2P) present in dorsal root ganglia (DRG). We previously demonstrated that THIK1 mRNA levels in the DRG dropped ipsilaterally 1day after CFA-induced cutaneous inflammation (CFA1). In this study we aimed to identify the currently unknown DRG subpopulations expressing THIK1, and to investigate the relationship between the channel and both inflammatory and spontaneous pain in normal rats. Using a combination of immunohistochemistry, western blotting and behavioural tests, we found that all small neurons and large groups of medium and large DRG neurons express THIK1. Myelinated and unmyelinated fibers, nerve endings in the skin and lamina I and II of the spinal cord also express the channel. THIK1 staining co-localizes with IB4-binding and trkA suggesting that the channel is expressed by nociceptors. At CFA1, both cytoplasmic and edge (membrane-associated) THIK1 staining were significantly reduced only in small neurons ipsilaterally compared to normal. At 4days after inflammation (CFA4), edge THIK1 staining levels in small neurons decreased bilaterally compared to normal. Medium and large size DRG neurons showed no change in THIK1 expression either at CFA1 or CFA4. Ipsilateral (but not contralateral) mean %intensities of THIK1 in small neurons at CFA1 correlated strongly negatively with spontaneous foot lifting (SFL) duration (a marker of spontaneous pain). Thus, nociceptors express THIK1 that can be regulated by cutaneous inflammation. Finally, in vivo siRNA knockdown of THIK1 resulted in longer SFL duration than siRNA scramble-treated rats. Taken together our evidence suggests a potential involvement for THIK1 in pain processing following inflammation.

Cutaneous Leishmaniasis Induces a Transmissible Dysbiotic Skin Microbiota that Promotes Skin Inflammation.

Skin microbiota can impact allergic and autoimmune responses, wound healing, and anti-microbial defense. We investigated the role of skin microbiota in cutaneous leishmaniasis and found that human patients infected with Leishmania braziliensis develop dysbiotic skin microbiota, characterized by increases in the abundance of Staphylococcus and/or Streptococcus. Mice infected with L. major exhibit similar changes depending upon disease severity. Importantly, this dysbiosis is not limited to the lesion site, but is transmissible to normal skin distant from the infection site and to skin from co-housed naive mice. This observation allowed us to test whether a pre-existing dysbiotic skin microbiota influences disease, and we found that challenging dysbiotic naive mice with L. major or testing for contact hypersensitivity results in exacerbated skin inflammatory responses. These findings demonstrate that a dysbiotic skin microbiota is not only a consequence of tissue stress, but also enhances inflammation, which has implications for many inflammatory cutaneous diseases.

The topical application of low-temperature argon plasma enhances the anti-inflammatory effect of Jaun-ointment on DNCB-induced NC/Nga mice.

BACKGROUND: Jaun-ointment (JO), also known as Shiunko in Japan, is one of the most popular medicinal formulae used in Korean traditional medicine for the external treatment of skin wound and inflammatory skin conditions. Since JO is composed of crude mixture of two herbal extracts (radix of Lithospermum erythrorhizon Siebold & Zucc and Angelica gigas Nakai), those been proved its anti-inflammatory activities in-vitro and in-vivo, JO has been expected as a good alternative treatment option for atopic dermatitis (AD). However, due to the lack of strategies for the penetrating methods of JO's various anti-inflammatory elements into the skin, an effective and safe transdermal drug delivery system needs to be determined. Here, low-temperature argon plasma (LTAP) was adopted as an ancillary partner of topically applied JO in a mice model of AD and the effectiveness was examined. METHODS: Dorsal skins of NC/Nga mice were challenged with DNCB (2,4-dinitrochlorobenzene) to induce AD. AD-like skin lesions were treated with JO alone, or in combination with LTAP. Inflammatory activity in the skin tissues was evaluated by histological analysis and several molecular biological tests. RESULTS: LTAP enhanced the effect of JO on AD-like skin lesion. Topical application of JO partially inhibited the development of DNCB-induced AD, shown by the moderate reduction of eosinophil homing and pro-inflammatory cytokine level. Combined treatment of JO and LTAP dramatically inhibited AD phenotypes. Interestingly, treatment with JO alone did not affect the activity of nuclear factor (NF)κB/RelA in the skin, but combined treatment of LTAP-JO blocked DCNB-mediated NFκB/RelA activation. CONCLUSIONS: LTAP markedly enhanced the anti-inflammatory activity of JO on AD-like skin lesions. The effect of LTAP may be attributed to enhancement of drug penetration and regulation of NFκB activity. Therefore, the combination treatment of JO and LTAP could be a potential strategy for the treatment of AD.

Pathophysiology of hidradenitis suppurativa.

The pathophysiology of hidradenitis suppurativa (HS) is not well understood. Some of our knowledge comes from clinical and epidemiological observations, along with studies of the histopathology and immunohistochemistry of affected skin. More recently, cutaneous molecular studies and transcriptomic analyses have provided additional information regarding inflammatory processes. The chronic cutaneous inflammation, systemic symptoms, and associated comorbidities suggest that HS should be classified as an immune-mediated disease, rather than a primary infectious disease. As such, a proposed integrated disease pathway is presented. At a fundamental level, there appears to be a primary abnormality in the pilosebaceous-apocrine unit, which leads to follicular occlusion, perifollicular cyst development that traps commensal microbes, and rupture into the dermis. This can trigger an exaggerated response of the cutaneous innate immune system. Initially this is an acute event, but ongoing intermittent disease activity can lead to recurrent inflammatory nodules and dermal tunnels. Once underway, the cutaneous inflammation is very difficult to turn off, leading to suppurative inflammation in whole anatomic regions. As the disease progresses, we propose that there is recruitment of the systemic immune system perpetuating the chronic cutaneous inflammatory process. There remains much to be done to understand the pathogenesis and immune signature of this challenging disease.

Diet phytochemicals and cutaneous carcinoma chemoprevention: A review.

Cutaneous carcinoma, which has occupied a peculiar place among worldwide populations, is commonly responsible for the considerably increasing morbidity and mortality rates. Currently available medical procedures fail to completely avoid cutaneous carcinoma development or to prevent mortality. Cancer chemoprevention, as an alternative strategy, is being considered to reduce the incidence and burden of cancers through chemical agents. Derived from dietary foods, phytochemicals have become safe and reliable compounds for the chemoprevention of cutaneous carcinoma by relieving multiple pathological processes, including oxidative damage, epigenetic alteration, chronic inflammation, angiogenesis, etc. In this review, we presented comprehensive knowledges, main molecular mechanisms for the initiation and development of cutaneous carcinoma as well as effects of various diet phytochemicals on chemoprevention.

Roles of Erythroid Differentiation Regulator 1 (Erdr1) on Inflammatory Skin Diseases.

Erythroid Differentiation Regulator 1 (Erdr1) is known as a hemoglobin synthesis factor which also regulates cell survival under conditions of stress. In addition, previous studies have revealed the effects of Erdr1 on cancer progression and its negative correlation with interleukin (IL)-18, a pro-inflammatory cytokine. Based on this evidence, the therapeutic effects of Erdr1 have been demonstrated in several inflammatory skin diseases such as malignant skin cancer, psoriasis, and rosacea. This article reviews the roles of Erdr1 in skin inflammation, suggesting that Erdr1 is a potential therapeutic molecule on inflammatory disorders.

Differential effectiveness of selected non-psychotropic phytocannabinoids on human sebocyte functions implicates their introduction in dry/seborrhoeic skin and acne treatment.

Acne is a common skin disease characterized by elevated sebum production and inflammation of the sebaceous glands. We have previously shown that a non-psychotropic phytocannabinoid ((-)-cannabidiol [CBD]) exerted complex anti-acne effects by normalizing 'pro-acne agents'-induced excessive sebaceous lipid production, reducing proliferation and alleviating inflammation in human SZ95 sebocytes. Therefore, in this study we aimed to explore the putative anti-acne effects of further non-psychotropic phytocannabinoids ((-)-cannabichromene [CBC], (-)-cannabidivarin [CBDV], (-)-cannabigerol [CBG], (-)-cannabigerovarin [CBGV] and (-)-Δ(9) -tetrahydrocannabivarin [THCV]). Viability and proliferation of human SZ95 sebocytes were investigated by MTT and CyQUANT assays; cell death and lipid synthesis were monitored by DilC1 (5)-SYTOX Green labelling and Nile Red staining, respectively. Inflammatory responses were investigated by monitoring expressions of selected cytokines upon lipopolysaccharide treatment (RT-qPCR, ELISA). Up to 10 µm, the phytocannabinoids only negligibly altered the viability of the sebocytes, whereas high doses (≥50 µm) induced apoptosis. Interestingly, basal sebaceous lipid synthesis was differentially modulated by the substances: CBC and THCV suppressed it, and CBDV had only minor effects, whereas CBG and CBGV increased it. Importantly, CBC, CBDV and THCV significantly reduced arachidonic acid (AA)-induced 'acne-like' lipogenesis. Moreover, THCV suppressed proliferation, and all phytocannabinoids exerted remarkable anti-inflammatory actions. Our data suggest that CBG and CBGV may have potential in the treatment of dry-skin syndrome, whereas CBC, CBDV and especially THCV show promise to become highly efficient, novel anti-acne agents. Moreover, based on their remarkable anti-inflammatory actions, phytocannabinoids could be efficient, yet safe novel tools in the management of cutaneous inflammations.