Targeting Aquaporin-3 Attenuates Skin Inflammation in Rosacea.

Rosacea is a common inflammatory skin disorder mediated by the dysregulation of both keratinocytes and T cells. Here, we report that aquaporin 3 (AQP3), a channel protein that mediates the transport of water/glycerol, was highly expressed in the epidermis and CD4+ T cells of both rosacea patients and experimental mice. Specifically, AQP3 deletion blocked the development of rosacea-like skin inflammation in model mice with LL37-induced rosacea-like disease. We also present mechanistic evidence showing that AQP3 was essential to the activation of NF-κB signaling and subsequent production of disease-characteristic chemokines in keratinocytes. Moreover, we show that AQP3 was upregulated during T cell differentiation and promotes helper T (Th) 17 differentiation possibly via the activation of STAT3 signaling. Our findings reveal that AQP3-mediated activation of NF-κB in keratinocytes and activation of STAT3 in CD4+ T cells acted synergistically and contributed to the inflammation in rosacea.

TLR7 promotes skin inflammation via activating NFκB-mTORC1 axis in rosacea.

Rosacea is a chronic inflammatory skin disease originated from damaged skin barrier and innate/adaptive immune dysregulation. Toll-like receptors (TLRs) sense injured skin and initiate downstream inflammatory and immune responses, whose role in rosacea is not fully understood. Here, via RNA-sequencing analysis, we found that the TLR signaling pathway is the top-ranked signaling pathway enriched in rosacea skin lesions, in which TLR7 is highlighted and positively correlated with the inflammation severity of disease. In LL37-induced rosacea-like mouse models, silencing TLR7 prevented the development of rosacea-like skin inflammation. Specifically, we demonstrated that overexpressing TLR7 in keratinocytes stimulates rapamycin-sensitive mTOR complex 1 (mTORC1) pathway via NFκB signaling. Ultimately, TLR7/NFκ B/mTORC1 axis promotes the production of cytokines and chemokines, leading to the migration of CD4+T cells, which are infiltrated in the lesional skin of rosacea. Our report reveals the crucial role of TLR7 in rosacea pathogenesis and indicatesa promising candidate for rosacea treatments.

Whole genome sequencing identifies genetic variants associated with neurogenic inflammation in rosacea.

Rosacea is a chronic inflammatory skin disorder with high incidence rate. Although genetic predisposition to rosacea is suggested by existing evidence, the genetic basis remains largely unknown. Here we present the integrated results of whole genome sequencing (WGS) in 3 large rosacea families and whole exome sequencing (WES) in 49 additional validation families. We identify single rare deleterious variants of LRRC4, SH3PXD2A and SLC26A8 in large families, respectively. The relevance of SH3PXD2A, SLC26A8 and LRR family genes in rosacea predisposition is underscored by presence of additional variants in independent families. Gene ontology analysis suggests that these genes encode proteins taking part in neural synaptic processes and cell adhesion. In vitro functional analysis shows that mutations in LRRC4, SH3PXD2A and SLC26A8 induce the production of vasoactive neuropeptides in human neural cells. In a mouse model recapitulating a recurrent Lrrc4 mutation from human patients, we find rosacea-like skin inflammation, underpinned by excessive vasoactive intestinal peptide (VIP) release by peripheral neurons. These findings strongly support familial inheritance and neurogenic inflammation in rosacea development and provide mechanistic insight into the etiopathogenesis of the condition.

Aberrant amino acid metabolism promotes neurovascular reactivity in rosacea.

Rosacea is a chronic skin disorder characterized by abnormal neurovascular and inflammatory conditions on the central face. Despite increasing evidence suggesting that rosacea is associated with metabolic disorders, the role of metabolism in rosacea pathogenesis remains unknown. Here, via a targeted metabolomics approach, we characterized significantly altered metabolic signatures in patients with rosacea, especially for amino acid-related metabolic pathways. Among these, glutamic acid and aspartic acid were highlighted and positively correlated with the disease severity in patients with rosacea. We further demonstrated that glutamic acid and aspartic acid can facilitate the development of erythema and telangiectasia, typical features of rosacea, in the skin of mice. Mechanistically, glutamic acid and aspartic acid stimulated the production of vasodilation-related neuropeptides from peripheral neurons and keratinocytes and induced the release of nitric oxide from endothelial cells and keratinocytes. Interestingly, we provided evidence showing that doxycycline can improve the symptoms of patients with rosacea possibly by targeting the amino acid metabolic pathway. These findings reveal that abnormal amino acid metabolism promotes neurovascular reactivity in rosacea and raise the possibility of targeting dysregulated metabolism as a promising strategy for clinical treatment.

Lithocholic acid promotes rosacea-like skin inflammation via G protein-coupled bile acid receptor 1.

BACKGROUND: Rosacea is a chronic inflammatory skin disorder with unclear etiology. Evidence showed that immunoinflammatory dysregulation was involved in the pathogenesis. Bile acids, as important participants of hepatoenteric circulation, play a vital role in immunoinflammatory regulation through peripheral blood circulation. However, whether it has effects on rosacea remains unknown. METHODS: Here, we performed a bile acid analysis on the serum samples of rosacea patients and healthy controls. Then we gavage G protein-coupled bile acid receptor 1 (TGR5) knockout mice with lithocholic acid (LCA) based on a LL37-induced rosacea-like model. We further overexpress TGR5 in HaCaT keratinocytes to figure out the downstream pathway. RESULTS: We found varied bile acid profile in the peripheral blood circulation of patients, especially the most significant increase in LCA. LCA promoted skin inflammation in LL37-induced rosacea-like mouse model. Our in vivo and in vitro results further demonstrated that LCA induced inflammatory cytokines and chemokines, thus exacerbated rosacea-like skin inflammation, via TGR5 in keratinocytes and LL37-induced rosacea-like mouse model. CONCLUSIONS: Therefore, we conclude that LCA promotes skin inflammation of rosacea via TGR5, and LCA-TGR5 axis may be a novel therapeutic target for rosacea.

Androgen Receptor-Mediated Paracrine Signaling Induces Regression of Blood Vessels in the Dermal Papilla in Androgenetic Alopecia.

Androgenetic alopecia (AGA), also known as male pattern baldness, is associated with androgen and androgen receptor (AR) signaling; however, the pathogenesis of AGA remains largely unknown. In this study, we show that nuclear localization of AR is elevated in the dermal papilla (DP) of balding scalp in patients with AGA. Transcriptome analysis identifies microvascular abnormalities in the DP of balding scalp compared with nonbalding scalp of patients with AGA. We provide further evidence that blood vessels regress in the DP of balding scalp at the early stage of hair follicle miniaturization in AGA development. Consistently, we find that microvascular vessels accumulate around the DP on anagen initiation, and angiogenesis is required for hair regeneration in mice. Mechanistically, we show that AR-mediated paracrine signaling, mainly TGFß signaling, from DP cells induces apoptosis of microvascular endothelial cells in the DP of balding scalp of AGA. These findings define a role of AR-mediated regression of blood vessels in DP in AGA and support the notion that early anti-AR treatment is better than late treatment.

A positive feedback loop between mTORC1 and cathelicidin promotes skin inflammation in rosacea.

Rosacea is a chronic inflammatory skin disorder whose pathogenesis is unclear. Here, several lines of evidence were provided to demonstrate that mTORC1 signaling is hyperactivated in the skin, especially in the epidermis, of both rosacea patients and a mouse model of rosacea-like skin inflammation. Both mTORC1 deletion in epithelium and inhibition by its specific inhibitors can block the development of rosacea-like skin inflammation in LL37-induced rosacea-like mouse model. Conversely, hyperactivation of mTORC1 signaling aggravated rosacea-like features. Mechanistically, mTORC1 regulates cathelicidin through a positive feedback loop, in which cathelicidin LL37 activates mTORC1 signaling by binding to Toll-like receptor 2 (TLR2) and thus in turn increases the expression of cathelicidin itself in keratinocytes. Moreover, excess cathelicidin LL37 induces both NF-κB activation and disease-characteristic cytokine and chemokine production possibly via mTORC1 signaling. Topical application of rapamycin improved clinical symptoms in rosacea patients, suggesting mTORC1 inhibition can serve as a novel therapeutic avenue for rosacea.

Aspirin alleviates skin inflammation and angiogenesis in rosacea.

Rosacea is a chronic, relapsing inflammatory skin disease featured by abnormal activation of immune responses, vascular dysfunction and prominent permeability barrier alterations. Aspirin, as the first nonsteroidal anti-inflammatory drug (NSAID), is widely used for various inflammatory conditions due to its anti-inflammatory and anti-angiogenic properties. However, its effects on rosacea are unclear. In this study, we demonstrated that aspirin dramatically improved pathological phenotypes in LL37-induced rosacea-like mice. The RNA-sequencing analysis revealed that aspirin alleviated rosacea-like skin dermatitis mainly via modulating immune responses. Mechanically, we showed that aspirin decreased the production of chemokines and cytokines associated with rosacea, and suppressed the Th1- and Th17-polarized immune responses in LL37-induced rosacea-like mice. Besides, aspirin administration decreased the microvessels density and the VEGF expression in rosacea-like skin. We further demonstrated that aspirin inhibited the activation of NF-κB signaling and the release of its downstream pro-inflammatory cytokines. Collectively we showed that aspirin exerts a curative effect on rosacea by attenuating skin inflammation and angiogenesis, suggesting a promising therapeutic candidate for the treatment of rosacea.

mTORC1-Mediated Angiogenesis is Required for the Development of Rosacea.

Although multiple evidences suggest that angiogenesis is associated with the pathophysiology of rosacea, its role is still in debate. Here, we showed that angiogenesis was enhanced in skin lesions of both rosacea patients and LL37-induced rosacea-like mice. Inhibition of angiogenesis alleviated LL37-induced rosacea-like features in mice. Mechanistically, we showed that mTORC1 was activated in the endothelial cells of the lesional skin from rosacea patients and LL37-induced rosacea-like mouse model. Inhibition of mTORC1 decreased angiogenesis and blocked the development of rosacea in mice. On the contrary, hyperactivation of mTORC1 increased angiogenesis and exacerbated rosacea-like phenotypes. Our in vitro results further demonstrated that inhibition of mTORC1 signaling significantly declined LL37-induced tube formation of human endothelial cells. Taken together, our findings revealed that mTORC1-mediated angiogenesis responding to LL37 might be essential for the development of rosacea and targeting angiogenesis might be a novel potential therapy.

An acidity-responsive polyoxometalate with inflammatory retention for NIR-II photothermal-enhanced chemodynamic antibacterial therapy.

Subcutaneous abscesses caused by drug-resistant pathogens pose a serious challenge to human health. To overcome this problem, herein an acidity-responsive aggregated W/Mo-based polyoxometalate (POM) was developed for photothermal-enhanced chemodynamic antibacterial therapy in the second near-infrared (NIR) region. The POM can self-assemble into larger-sized aggregates with stronger absorption in the NIR region, making it remain in the acidic infected tissue. Furthermore, the hydrogen peroxide at the site of infection can be converted to a hydroxyl radical for chemodynamic therapy (CDT) and simultaneously the glutathione in organisms is consumed by the POM to further enhance the CDT effect. More importantly, under laser irradiation, the hyperthermia produced by the POM not only can kill drug-resistant Staphylococcus aureus, but also enhance the performance of CDT. Benefitting from the inflammatory retention and acidity-responsive photothermal-enhanced CDT properties, the POM exhibits an obvious therapeutic effect against drug-resistant bacterial infection without significant side effects under 1060 nm laser irradiation.

Platelet factor 4 inhibits human hair follicle growth and promotes androgen receptor expression in human dermal papilla cells.

Platelet-rich plasma (PRP) has been reported recently as a potential therapeutic approach for alopecia, such as androgenetic alopecia, but the exact mechanisms and effects of specific components of this recipe remain largely unknown. In this study, we identified that platelet factor 4 (PF4), a component of PRP, significantly suppressed human hair follicle growth and restrained the proliferation of human dermal papilla cells (hDPCs). Furthermore, our results showed that PF4 upregulated androgen receptor (AR) in human dermal papilla cells in vitro and via hair follicle organ culture. Among the hair growth-promoting and DP-signature genes investigated, PF4 decreased the expression of Wnt5a, Wnt10b, LEF1, HEY1 and IGF-1, and increased DKK1 expression, but did not affect BMP2 and BMP4 expression. Collectively, Our data demonstrate that PF4 suppresses human hair follicle growth possibly via upregulating androgen receptor signaling and modulating hair growth-associated genes, which provides thought-provoking insights into the application and optimization of PRP in treating hair loss.

ADAMDEC1 promotes skin inflammation in rosacea via modulating the polarization of M1 macrophages.

Rosacea is a chronic inflammatory cutaneous disease which mainly affects central face, leading to cosmetic disfigurement and compromised social psychology in billions of rosacea patients. Though the exact etiology of rosacea remains elusive, accumulating evidence has highlighted the dysfunction of innate immunity and inflammation in rosacea pathogenesis. Disintegrin Metalloprotease ADAM-like Decysin-1 (ADAMDEC1) is an orphan ADAM-like metalloprotease which is believed to be closely related to inflammation. Here for the first time, we reported that Adamdec1 expression was significantly increased in the skin lesions of rosacea patients and LL37-induced rosacea-like mouse models. Immunofluorescence analysis revealed co-localization of ADAMDEC1 and macrophages in patient and mouse biopsies. In cellular experiment, the expression of ADAMDEC1 was prominently elevated in M1 but not M2 macrophages. Knocking down of ADAMDEC1 significantly blunted M1 polarization in macrophages induced from human monocytes and THP-1 cell lines. Furthermore, silencing of Adamdec1 in LL-37-induced mouse model also suppressed the expression of M1 signature genes such as IL-6, iNOS and TNF-α, resulting in attenuated rosacea-like phenotype and inflammation. Taken together, our results demonstrate that ADAMDEC1 plays a pro-inflammatory role in rosacea via modulating the M1 polarization of macrophages.

Thalidomide ameliorates rosacea-like skin inflammation and suppresses NF-κB activation in keratinocytes.

BACKGROUND: Rosacea is a chronic inflammatory skin disorder of uncertain etiology. Evidence suggests the underlying pathogenesis is modulated by abnormal inflammatory and vascular responses. Thalidomide is a synthetic derivative acid with anti-inflammatory and anti-angiogenic properties. However, its effects on rosacea remain unknown. OBJECTIVES: To investigate the effects of thalidomide on the lesional alterations and molecular mechanisms in rosacea. METHODS: Mice were intradermally injected with LL37 to induce rosacea-like features and intraperitoneally administered with thalidomide. The severity of skin inflammation was evaluated. The mRNA levels of cytokines and chemokines associated with rosacea were assessed by qPCR. The number of CD4 positive infiltrated T helper cells and CD31 positive microvessels, and related-genes were measured by immunofluorescence, qPCR and ELISA. Moreover, the effect of thalidomide on inhibiting NF-κB activation was determined by immunofluorescence and western blot. RESULTS: Our results showed that thalidomide significantly alleviated erythema and reduced inflammatory cell infiltration in dermis of LL37-induced rosacea-like mice. The production of cytokines and chemokines induced by LL37 was decreased by thalidomide in mice skin and HaCaT keratinocytes. Particularly, we showed thalidomide reduced CD4+ T helper cell infiltration and downregulated Th1- and Th17-polarizing genes. In addition, thalidomide treatment lowered the microvessel density and vascular endothelial growth factor (VEGF) expression. We further demonstrated that thalidomide suppressed NF-κB activation in LL37-treated skin and in TNF-α-stimulated HaCaT keratinocytes in vitro. CONCLUSIONS: Our findings suggest thalidomide attenuates the inflammation and represses NF-κB activation in skin, which leads to assumptions that thalidomide may be a new therapeutic agent for rosacea.

Claudin reduction may relate to an impaired skin barrier in rosacea.

Rosacea is a chronic inflammatory skin disorder whose pathophysiological mechanism remains largely unknown. Although recent studies have revealed the hypersensitivity of the skin towards chemical, thermal and biological stimuli, there is no direct molecular evidence suggesting the skin barrier is impaired in rosacea. In this study, we demonstrated that the mRNA levels of most claudins (CLDN), the main components of tight junctions determining the major barrier of the paracellular pathway between epithelial cells, were lowered in lesional skin of rosacea patients, especially with erythematotelangiectatic (ETR) and papulopustular (PPR) subtypes. Immunohistochemical analysis showed a significant decrease in the expression of CLDN1, CLDN3, CLDN4 and CLDN5 in the epidermis of ETR and PPR patients. However, the expression of other skin barrier genes, such as filaggrin, loricrin and keratin 10, was not altered. In vitro, various rosacea trigger factors reduced the protein levels of CLDN1, CLDN3 and CLDN5 in keratinocytes. Taken together, our results demonstrate a significant decrease in the expression of CLDN rather than other skin barrier genes, which may be associated with an impaired skin barrier responsible for the development of rosacea.

Rhodium-Catalyzed Tandem Reaction of Isocyanides with Azides and Oxygen Nucleophiles: Synthesis of Isoureas.

A novel rhodium-catalyzed tandem reaction of isocyanides with azides and various oxygen nucleophiles has been developed. The reaction provides a simple and highly efficient one-pot synthesis of various N-sulfonyl/acylisoureas with broad substrate scope in an atom-economical manner from readily available starting materials in a highly stereoselective manner.

Thermally induced formal [4+2] cycloaddition of 3-aminocyclobutenones with electron-deficient alkynes: facile and efficient synthesis of 4-pyridones.

A thermally induced novel formal [4+2] cycloaddition of cyclobutenones with electron-deficient alkynes under metal-free conditions has been developed for the first time. The reaction can proceed in a highly regioselective manner and provides a straightforward and efficient method for the synthesis of 4-pyridone derivatives from readily available starting materials in a single step.

The Rosacea-specific Quality-of-Life instrument (RosQol): Revision and validation among Chinese patients.

Rosacea is a common chronic facial disorder that affects patients' health-related quality of life; the only questionnaire designed specifically for rosacea is the Rosacea-specific Quality-of-Life instrument (RosQol). However, the questionnaire has not been validated among Chinese patients. This study aimed to validate the Chinese version of the RosQol. First, we translated the questionnaire into Chinese. Then, rosacea patients completed the RosQol and Dermatology Life Quality Index, indicating the disease's impact on their lives. We also collected patients' demographic and clinical data, including symptom self-evaluation scores and rosacea severity scores. Internal consistency was determined by using Cronbach's alpha, test-retest reliability, and Spearman's correlation. Criterion-related validity and internal construct validity were also determined. Most RosQol items showed good internal consistency. However, items 13 and 19 were not sufficiently sensitive for use in the Chinese population; we deleted them and constructed the adjusted Chinese-version RosQol, which had good reliability and validity. When patients' clinical symptoms changed, the scores on the relevant dimensions of the adjusted RosQol also changed. Some RosQol items were not suitable for use in the Chinese sample. The adjusted Chinese-version RosQol was easy to complete, well received by patients, and demonstrated acceptable validity and reliability.