cis-Khellactone Inhibited the Proinflammatory Macrophages via Promoting Autophagy to Ameliorate Imiquimod-Induced Psoriasis

New insight in treating autoimmune diseases by targeting autophagy

Autophagy is a highly conserved biological process in eukaryotes, which degrades cellular misfolded proteins, damaged organelles and invasive pathogens in the lysosome-dependent manner. Autoimmune diseases caused by genetic elements, environments and aberrant immune responses severely impact patients' living quality and even threaten life. Recently, numerous studies have reported autophagy can regulate immune responses, and play an important role in autoimmune diseases. In this review, we summarised the features of autophagy and autophagy-related genes, enumerated some autophagy-related genes involved in autoimmune diseases, and further overviewed how to treat autoimmune diseases through targeting autophagy. Finally, we outlooked the prospect of relieving and curing autoimmune diseases by targeting autophagy pathway.

Impaired autophagy in myeloid cells aggravates psoriasis-like skin inflammation through the IL-1β/CXCL2/neutrophil axis

BACKGROUND

Psoriasis is an inflammatory skin disease characterized by the hyperproliferative epidermal keratinocytes and significant immune cells infiltration, leading to cytokines production such as IL-1β, TNF-α, IL-23, and IL-17. Recent study highlights the critical role of IL-1β in the induction and activation of pathogenic Th17 and IL-17-producing γδ T cells, contributing to psoriasis. However, the mechanism underlying IL-1β dysregulation in psoriasis pathogenesis is unclear. Autophagy regulates IL-1β production and has a pleiotropic effect on inflammatory disorders. Previous studies showed controversial role of autophagy in psoriasis pathogenesis, either pro-inflammatory in autophagy-deficient keratinocyte or anti-inflammatory in pharmacologically autophagy-promoting macrophages. Thus, the direct role of autophagy and its therapeutic potential in psoriasis remains unclear.

METHODS

We used myeloid cell-specific autophagy-related gene 7 (Atg7)-deficient mice and determined the effect of autophagy deficiency in myeloid cells on neutrophilia and disease pathogenesis in an imiquimod-induced psoriasis mouse model. We then assessed the pathogenic mechanism focusing on immune cells producing IL-1β and IL-17 along with gene expression profiles associated with psoriasis in mouse model and public database on patients. Moreover, therapeutic potential of IL-1β blocking in such context was assessed.

RESULTS

We found that autophagy deficiency in myeloid cells exacerbated neutrophilic inflammation and disease pathogenesis in mice with psoriasis. This autophagy-dependent effect was associated with a significant increase in IL-1β production from myeloid cells, particularly macrophages, Cxcl2 expression, and IL-17 A producing T cells including γδ T cells. Supporting this, treatment with systemic IL-1 receptor blocking antibody or topical saccharin, a disaccharide suppressing pro-IL-1β expression, led to the alleviation of neutrophilia and psoriatic skin inflammation linked to autophagy deficiency. The pathophysiological relevance of this finding was supported by dysregulation of autophagy-related genes and their correlation with Th17 cytokines in psoriatic skin lesion from patients with psoriasis.

CONCLUSIONS

Our results suggest that autophagy dysfunction in myeloid cells, especially macrophages, along with IL-1β dysregulation has a causal role in neutrophilic inflammation and psoriasis pathogenesis.

The multifaceted role of autophagy in skin autoimmune disorders: a guardian or culprit?

Autophagy is a cellular process that functions to maintain intracellular homeostasis via the degradation and recycling of defective organelles or damaged proteins. This dynamic mechanism participates in various biological processes, such as the regulation of cellular differentiation, proliferation, survival, and the modulation of inflammation and immune responses. Recent evidence has demonstrated the involvement of polymorphisms in autophagy-related genes in various skin autoimmune diseases. In addition, autophagy, along with autophagy-related proteins, also contributes to homeostasis maintenance and immune regulation in the skin, which is associated with skin autoimmune disorders. This review aims to provide an overview of the multifaceted role of autophagy in skin autoimmune diseases and shed light on the potential of autophagy-targeting therapeutic strategies in dermatology.

Skin barrier-inflammatory pathway is a driver of the psoriasis-atopic dermatitis transition

As chronic inflammatory conditions driven by immune dysregulation are influenced by genetics and environment factors, psoriasis and atopic dermatitis (AD) have traditionally been considered to be distinct diseases characterized by different T cell responses. Psoriasis, associated with type 17 helper T (Th17)-mediated inflammation, presents as well-defined scaly plaques with minimal pruritus. AD, primarily linked to Th2-mediated inflammation, presents with poorly defined erythema, dry skin, and intense itching. However, psoriasis and AD may overlap or transition into one another spontaneously, independent of biological agent usage. Emerging evidence suggests that defects in skin barrier-related molecules interact with the polarization of T cells, which forms a skin barrier-inflammatory loop with them. This loop contributes to the chronicity of the primary disease or the transition between psoriasis and AD. This review aimed to elucidate the mechanisms underlying skin barrier defects in driving the overlap between psoriasis and AD. In this review, the importance of repairing the skin barrier was underscored, and the significance of tailoring biologic treatments based on individual immune status instead of solely adhering to the treatment guidelines for AD or psoriasis was emphasized.

Celastrol regulates psoriatic inflammation and autophagy by targeting IL-17A

Anti-IL-17A antibodies, such as secukinumab and ixekizumab, are effective proinflammatory cytokine inhibitors for autoimmune disorders, including psoriasis. However, anti-IL-17A small molecule treatments are yet to be commercialized. Celastrol, a natural compound extracted from the roots of traditional Chinese medicinal plants, has anti-inflammatory and antioxidant properties. However, the binding of celastrol to IL-17A and the associated anti-inflammatory mechanisms remain unclear. This study investigated whether celastrol could directly bind to IL-17A and regulate inflammation in psoriatic in vitro and in vivo models. The results showed that celastrol directly binds to IL-17A and inhibits its downstream signaling, including the NF-kB and MAPK pathways. Interestingly, celastrol restored autophagy dysfunction and reduced proinflammatory cytokine secretion in keratinocytes. In addition, celastrol increased autophagy in the epidermis of a mouse model of psoriasis. Celastrol decreased Th17 cell populations and proinflammatory cytokine levels in mice. Thus, IL-17A-targeting celastrol reduced inflammation by rescuing impaired autophagy in in vitro and in vivo models of psoriasis, demonstrating its potential as a substitute for anti-IL-17A antibodies for treating psoriasis.

Bioinformatic Analysis to Identify and Cellular Experiments to Validate Autophagy-related Genes in Psoriasis

PURPOSE

To explore differentially expressed genes (DEGs) associated with autophagy in psoriasis using bioinformatics analysis and verify them in an M5-induced psoriatic cell model.

METHODS

We obtained gene expression microarray data from patients with psoriasis and normal skin tissues from the dataset GSE78097 of the NCBI Gene Expression Omnibus (GEO) database. R software was used to identify DEGs associated with autophagy in psoriasis. Proteinprotein interaction (PPI) and correlation analyses were used to show interactions between certain genes. Their potential biological roles were determined using Gene Ontology (GO) and Kyoto Encyclopedia of Genes and Genomes (KEGG) enrichment analyses. Finally, all the DEGs associated with autophagy in psoriasis were validated in a psoriatic cell model by RT-qPCR.

RESULTS

28 DEGs associated with autophagy were identified. These genes were linked to one another, and the most connected hub gene was VEGFA, according to PPI analysis. GO and KEGG enrichment analyses revealed various biological pathways associated with autophagy. The RT-qPCR findings of the expression of 18 genes in the psoriatic cell model confirmed the bioinformatics analysis results. The five genes with the most significant differences were IL24, CCL2, NAMPT, PPP1R15A, and SPHK1.

CONCLUSION

We identified DEGs associated with autophagy in patients with psoriasis. IL24, CCL2, NAMPT, PPP1R15A, and SPHK1 were identified as important genes that may influence psoriasis development through the regulation of autophagy.

Insights into Autophagic Machinery and Lysosomal Function in Cells Involved in the Psoriatic Immune-Mediated Inflammatory Cascade

Impaired autophagy, due to the dysfunction of lysosomal organelles, contributes to maladaptive responses by pathways central to the immune system. Deciphering the immune-inflammatory ecosystem is essential, but remains a major challenge in terms of understanding the mechanisms responsible for autoimmune diseases. Accumulating evidence implicates a role that is played by a dysfunctional autophagy-lysosomal pathway (ALP) and an immune niche in psoriasis (Ps), one of the most common chronic skin diseases, characterized by the co-existence of autoimmune and autoinflammatory responses. The dysregulated autophagy associated with the defective lysosomal system is only one aspect of Ps pathogenesis. It probably cannot fully explain the pathomechanism involved in Ps, but it is likely important and should be seriously considered in Ps research. This review provides a recent update on discoveries in the field. Also, it sheds light on how the dysregulation of intracellular pathways, coming from modulated autophagy and endolysosomal trafficking, characteristic of key players of the disease, i.e., skin-resident cells, as well as circulating immune cells, may be responsible for immune impairment and the development of Ps.

Phytochemicals: Targeting autophagy to treat psoriasis

BACKGROUND

Psoriasis is an immune-mediated chronic inflammatory skin disease characterized by well-defined erythema and white scales, which affects approximately 2% of the worldwide population and causes long-term distress to patients. Therefore, development of safe and effective therapeutic drugs is imminent. Autophagy, an evolutionarily conserved catabolic process, degrades intracellular constituents to maintain cellular energy homeostasis. Numerous studies have revealed that autophagy is closely related to immune function, such as removal of intracellular bacteria, inflammatory cytokine secretion, antigen presentation, and lymphocyte development. Phytochemicals derived from natural plants are often used to treat psoriasis due to their unique therapeutic properties and favorable safety. So far, a mass of phytochemicals have been proven to be able to activate autophagy and thus alleviate psoriasis. This review aimed to provide directions for finding phytochemicals that target autophagy to treat psoriasis.

METHODS

The relevant literatures were collected from classical TCM books and a variety of databases (PubMed, Google Scholar, ScienceDirect, Springer Link, Web of Science and China National Knowledge Infrastructure) till December 2022. Search terms were "Phytochemical", "Psoriasis" and "Autophagy". The retrieved data followed PRISMA criteria (preferred reporting items for systematic review).

RESULTS

Phytochemicals treat psoriasis mainly through regulating immune cell function, inhibiting excessive inflammatory response, and reducing oxidative stress. While the role and mechanism of autophagy in the pathogenesis of psoriasis have been confirmed in human trials, most of the evidence for phytochemicals that target autophagy to treat psoriasis comes from animal studies. The research focusing on the role of phytochemical-mediated autophagy in the prevention and treatment of psoriasis is limited, and the definite relationship between phytochemical-regulated autophagy and treatment of psoriasis still deserves further experimental confirmation.

CONCLUSIONS

Phytochemicals with autophagic activities will provide new insights into the therapeutic intervention for psoriasis.

Inhibitory Activity of Natural cis-Khellactone on Soluble Epoxide Hydrolase and Proinflammatory Cytokine Production in Lipopolysaccharides-Stimulated RAW264.7 Cells

The pursuit of anti-inflammatory agents has led to intensive research on the inhibition of soluble epoxide hydrolase (sEH) and cytokine production using medicinal plants. In this study, we evaluated the efficacy of cis-khellactone, a compound isolated for the first time from the roots of Peucedanum japonicum. The compound was found to be a competitive inhibitor of sEH, exhibiting an IC50 value of 3.1 ± 2.5 µM and ki value of 3.5 µM. Molecular docking and dynamics simulations illustrated the binding pose of (-)cis-khellactone within the active site of sEH. The results suggest that binding of the inhibitor to the enzyme is largely dependent on the Trp336-Gln384 loop within the active site. Further, cis-khellactone was found to inhibit pro-inflammatory cytokines, including NO, iNOS, IL-1β, and IL-4. These findings affirm that cis-khellactone could serve as a natural therapeutic candidate for the treatment of inflammation.

Tectorigenin inhibits inflammation in keratinocytes by inhibition of NLRP3 inflammasome regulated by the TLR4/NF-κB pathway

BACKGROUND

Psoriasis is a prevalent inflammatory skin disease characterized by excessive proliferation and abnormal differentiation of keratinocytes, and infiltration of inflammatory cells into the epidermis. However, the underlying mechanisms remain unclear. Tectorigenin is an active ingredient in traditional medicines and has anti-inflammatory activity. This research explored the effects of tectorigenin on the anti-inflammatory property, autophagy, and the underlying mechanisms in M5 ([IL-22, IL-17A, oncostatin M, IL-1α, and TNF-α])-stimulated HaCaT cells.

METHODS

The in vitro model of mixed M5 cytokines-stimulated HaCaT keratinocytes was established to investigate the phenotypic features in psoriasis. Cell viability was assessed by MTT (3-[4,5-dimethylthiazol-2-yl]-2,5-diphenyltetrazolium bromide) assay, cell proliferative rate by EdU (5-ethynyl-2'-deoxyuridine) assay, and autophagy was detected by immunofluorescence staining. After M5 exposure, the proliferative rate, protein expression of autophagy, and signaling activities of NLR family pyrin domain containing 3 (NLRP3) inflammasome and toll-like receptor 4 (TLR4)/nuclear factor-κB (NF-κB) were measured. The latter were quantitated using quantitative PCR and western blot, respectively. The inflammatory response was detected by enzyme-linked immunosorbent assay (ELISA).

RESULTS

Tectorigenin exerted a protective effect in ameliorating the hyperproliferation and inflammation of HaCaT keratinocytes induced by M5 cytokines. Furthermore, tectorigenin on keratinocytes seemed to inactivate NLRP3 inflammasome and inhibit cell proliferation and inflammation response via suppression of TLR4/NF-κB pathway.

CONCLUSION

This study proves that tectorigenin may be a potential therapeutic candidate for psoriasis treatment in future.

A plant-derived glucocorticoid receptor modulator with potency to attenuate the side effects of glucocorticoid therapy

BACKGROUND AND PURPOSE

Continuous efforts have been made to move towards maintaining the beneficial anti-inflammatory functions of glucocorticoids (GCs) while minimizing side effects. Here, we investigated the selective glucocorticoid receptor (GR) modulator-like properties of a plant-derived compound caesaldekarin e (CA-e).

EXPERIMENTAL APPROACH

The therapeutic efficacy of CA-e was evaluated in several mouse models, including dextran sulfate sodium-induced colitis, ovalbumin-induced lung allergic inflammation, imiquimod-induced psoriasis-like skin inflammation and skin atrophy. The action of CA-e targeting the GR was analysed using molecular docking, cellular thermal shift assays and microscale thermophoresis. Other methods included DNA-protein pull-down assays and mass spectrometry.

KEY RESULTS

CA-e selectively inhibited positive GC response element ((+) GRE)-mediated direct transactivation while maintaining and even enhancing the anti-inflammatory effects of treatment with dexamethasone. CA-e, alone and in combination with dexamethasone, efficiently alleviated inflammation in several mouse models with milder side effects compared with dexamethasone alone. Mechanistically, CA-e inhibited the formation of dimers by binding to the dimerization interface located in the ligand-binding domain of GR and facilitated embryonic ectoderm development that is involved in the regulation of transcriptional repression to compete for binding to (+) GRE, eventually leading to the repression of (+) GRE-regulated genes. In addition, CA-e repressed NF-κB-dependent genes by enhancing the interaction between GR and p65.

CONCLUSIONS AND IMPLICATIONS

Our results reveal that CA-e is a novel GR modulator with strong potency to attenuate the side effects of GC therapy and can be used as a potential molecular tool for deciphering GR signalling.

Crucial role of Ca2+ /CN signalling pathway in the antifungal activity of disenecioyl-cis-khellactone against Botrytis cinerea

BACKGROUND

Botrytis cinerea causes grey mould and is one of the most destructive fungal pathogens affecting important fruit and vegetable crops. In preliminary studies, we found that disenecioyl-cis-khellactone (DK) had strong antifungal activity against several fungi species including B. cinerea [half maximal effective concentration (EC₅₀ ) = 11.0 μg mL^-1 ]. In this study, we aimed to further evaluate the antifungal activity of DK against B. cinerea and determine the role of calcium ion/calcineurin (Ca²⁺ /CN) signalling pathway on its antifungal effect.

RESULTS

DK was effective against B. cinerea in both in vitro and in vivo assays. Exogenous Ca²⁺ reduced the antifungal activity of DK. The combination of DK and cyclosporine A (CsA) did not exhibit an additive effect against B. cinerea. In contrast to CsA, DK reduced the intracellular Ca²⁺ concentration in B. cinerea. DK bound to calcineurin A (cnA) and up-regulated the expression of PMC1 and PMR1 genes. Moreover, DK sensitivity of △bccnA significantly decreased compared with that of Bc05.10 strain.

CONCLUSION

DK is a promising lead compound for developing fungicides against B. cinerea. The Ca²⁺ /CN signalling pathway plays a crucial role in the DK antifungal activity, and cnA is one of the targets of DK against B. cinerea. DK directly reacts with cnA, which up-regulates the transcription of Ca²⁺ /CN-dependent target genes PMC1 and PMR1, decreasing the intracellular Ca²⁺ concentration and disturbing the intracellular Ca²⁺ balance, leading to cell death. © 2022 Society of Chemical Industry.

Advances in the modulation of ROS and transdermal administration for anti-psoriatic nanotherapies

Reactive oxygen species (ROS) at supraphysiological concentration have a determinate role in contributing to immuno-metabolic disorders in the epithelial immune microenvironment (EIME) of psoriatic lesions. With an exclusive focus on the gene-oxidative stress environment interaction in the EIME, a comprehensive strategy based on ROS-regulating nanomedicines is greatly anticipated to become the mainstay of anti-psoriasis treatment. This potential therapeutic modality could inhibit the acceleration of psoriasis via remodeling the redox equilibrium and reshaping the EIME. Herein, we present a marked overview of the current progress in the pathomechanisms of psoriasis, with particular concerns on the potential pathogenic role of ROS, which significantly dysregulates redox metabolism of keratinocytes (KCs) and skin-resident or -infiltrating cells. Meanwhile, the emergence of versatile nanomaterial-guided evolution for transdermal drug delivery has been attractive for the percutaneous administration of antipsoriatic therapies in recent years. We emphasize the underlying molecular mechanism of ROS-based nanoreactors for improved therapeutic outcomes against psoriasis and summarize up-to-date progress relating to the advantages and limitations of nanotherapeutic application for transdermal administration, as well as update an insight into potential future directions for nanotherapies in ROS-related skin diseases.

Interactions of Autophagy and the Immune System in Health and Diseases

Autophagy is a highly conserved process that utilizes lysosomes to selectively degrade a variety of intracellular cargo, thus providing quality control over cellular components and maintaining cellular regulatory functions. Autophagy is triggered by multiple stimuli ranging from nutrient starvation to microbial infection. Autophagy extensively shapes and modulates the inflammatory response, the concerted action of immune cells, and secreted mediators aimed to eradicate a microbial infection or to heal sterile tissue damage. Here, we first review how autophagy affects innate immune signaling, cell-autonomous immune defense, and adaptive immunity. Then, we discuss the role of non-canonical autophagy in microbial infections and inflammation. Finally, we review how crosstalk between autophagy and inflammation influences infectious, metabolic, and autoimmune disorders.

Signaling pathways and targets of natural products in psoriasis treatment

Aim: Psoriasis is a common chronic inflammatory skin disorder, which has adverse effects on patients’ quality of life. Natural products exhibit significant therapeutic capacities with small side effects and might be preferable alternative treatments for patients with psoriasis. This study summarizes the signaling pathways with the potential targets of natural products and their efficacy for psoriasis treatment. Methods: The literature for this article was acquired from PubMed and Web of Science, from January 2010 to December 2020. The keywords for searching included “psoriasis” and “natural product”, “herbal medicine”, “herbal therapy”, “medicinal plant”, “medicinal herb” or “pharmaceutical plant”. Results: Herbal extracts, natural compounds, and herbal prescriptions could regulate the signaling pathways to alleviate psoriasis symptoms, such as T helper 17 (Th17) differentiation, Janus kinase (JAK)/signal transducer and activator of transcription (STAT), nuclear factor-kappa B (NF-κB), mitogen‑activated protein kinase (MAPK), phosphatidylinositol 3-kinase (PI3K)/Akt/mammalian target of rapamycin (mTOR), and other signaling pathways, which are involved in the inflammatory response and keratinocyte hyperproliferation. The anti-psoriatic effect of natural products in clinical trials was summarized. Conclusions: Natural products exerted the anti-psoriatic effect by targeting multiple signaling pathways, providing evidence for the investigation of novel drugs. Further experimental research should be performed to screen and characterize the therapeutic targets of natural products for application in psoriasis treatment.

A multifunctional composite hydrogel as an intrinsic and extrinsic coregulator for enhanced therapeutic efficacy for psoriasis

Background

Psoriasis is a chronic relapsing immunological skin disease characterized by multiple cross-talk inflammatory circuits which are relevantly associated with abnormal cross-reactivity between immune cells and keratinocytes (KCs). It may be inadequate to eradicate complicated pathogenesis only via single-mode therapy. To provide optimal combinatory therapeutics, a nanocomposite-based hydrogel was constructed by loading methotrexate (MTX) into ZnO/Ag to realize combined multiple target therapy of psoriasis.

Results

In this composite hydrogel, ZnO hybrid mesoporous microspheres were utilized both as drug carriers and reactive oxygen species (ROS)-scavenging nanoparticles. A proper amount of Ag nanoparticle-anchored ZnO nanoparticles (ZnO/Ag) was functionalized with inherent immunoregulatory property. The experiments showed that ZnO/Ag nanoparticles could exhibit a self-therapeutic effect that was attributed to reducing innate cytokine profiles by inactivating p65 in proinflammatory macrophages and abrogating secretion of adaptive cytokines in KCs by downregulating ROS-mediated STAT3-cyclin D1 signaling. A preferable antipsoriatic efficacy was achieved via topical administration of this hydrogel on the imiquimod (IMQ)-induced psoriasis mice model, demonstrating the superior transdermal delivery and combined enhancement of therapeutic efficacy caused by intrinsic nanoparticles and extrinsic MTX.

Conclusion

This composite hydrogel could serve as a multifunctional, nonirritating, noninvasive and effective transcutaneous nanoagent against psoriasis.

Graphical Abstract

Supplementary Information

The online version contains supplementary material available at 10.1186/s12951-022-01368-y.

TMT-based proteomics analysis reveals the protective effect of Jueyin granules on imiquimod-induced psoriasis mouse model by causing autophagy

BACKGROUND

Psoriasis is a chronic relapsing inflammatory skin disease that may markedly influence the patients' physical health and mental condition. According to animal models and clinical researches, it has been proved that Jueyin granules (JYG), a Chinese formula comprised of seven kinds of Traditional Chinese Medicine (TCM), is a therapeutic agent for treating psoriasis, while the specific mechanisms of the anti-inflammation effects of JYG have not been fully elucidated.

OBJECTIVE

To uncover the underlying mechanisms of the action of JYG on psoriasis by proteomics clues.

MATERIALS AND METHODS

Differentially expressed proteins (DEPs) were explored by tandem mass tag (TMT)-based quantitative proteomics analysis after JYG treatment (administered intragastrically for 12 days). Bioinformatics analysis of DEPs was conducted through hierarchical clustering, volcano plot, gene ontology (GO), and Kyoto Encyclopedia of Genes and Genomes (KEGG) analysis. Major DEPs were further identified by enzyme-linked immunoassay (ELISA) and real-time quantitative polymerase chain reaction (qRT-PCR).

RESULTS

Ninety-five DEPs were identified, including 57 up-regulated and 38 down-regulated proteins, between imiquimod (IMQ) and IMQ+JYG groups. GO analysis indicated that DEPs were mainly associated with keratin filament, intermediate filament, extracellular exosome, extracellular space, innate immune response, keratinization, and keratinocyte differentiation. The KEGG pathway analysis manifested that estrogen signaling pathway, cholesterol metabolism, fat digestion, absorption, peroxisome proliferator-activated receptor (PPAR), and interleukin (IL)-17 signaling pathway might be the paramount pathways, through which JYG functioned on psoriasis. Furthermore, we determined that JYG could regulate macrophage and CD4+ T cell phenotypes by inducing autophagy.

CONCLUSIONS

JYG may induce autophagy by up-regulating ApoA1 and inhibit the infiltration of CD4+ T cells and macrophages, thereby alleviating IMQ-induced psoriatic inflammation.

Mesenchymal Stem Cell-Derived Extracellular Vesicles with High PD-L1 Expression for Autoimmune Diseases Treatment

Autoimmune diseases are the third most common disease influencing the quality of life of many patients. Here, a programmed cell death-ligand 1 + (PD-L1) mesenchymal stem cell (MSC) derived extracellular vesicles (MSC-sEVs-PD-L1) using lentivirus-mediated gene transfection technology is developed for reconfiguration of the local immune microenvironment of affected tissue in autoimmune diseases. MSC-sEVs-PD-L1 exhibits an impressive ability to regulate various activated immune cells to an immunosuppressed state in vitro. More importantly, in dextran sulfate sodium-induced ulcerative colitis (UC) and imiquimod-induced psoriasis mouse models, a significantly high accumulation of MSC-sEVs-PD-L1 is observed in the inflamed tissues compared to the PD-L1+ MSCs. Therapeutic efficiency in both UC and psoriasis mouse disease models is demonstrated using MSC-sEVs-PD-L1 to reshape the inflammatory ecosystem in the local immune context. A technology is developed using MSC-sEVs-PD-L1 as a natural delivery platform for autoimmune diseases treatment with high clinical potential.

Autophagy in skin barrier and immune-related skin diseases

Autophagy is a process which is highly conserved in eukaryotes to degrade or recycle cytoplasmic components through lysosomes to maintain cellular homeostasis. Recent studies have shown that autophagy also plays critical roles in cell apoptosis, inflammation, pathogen clearance, and so on under stressed conditions and thereby has been linked to a variety of human disorders. The skin is the largest organ of the body and serves as the first line of defense against environmental insult. Skin as a nutrient-poor environment requires recycling of limited resources via the autophagy machinery to maintain homeostasis. Therefore, dysregulation of autophagy has been linked to skin diseases. In this review, we describe the molecular machinery and regulation of autophagy, discuss its role in keratinocytes and skin barrier, skin immune cells, and immune-related skin diseases including autoimmune skin disorders, allergic skin diseases, infectious skin disorders, and antitumor immunity against skin tumor. Finally, we highlight the potential of autophagy as a therapeutic target for immune-related skin diseases, and delivery of autophagy-related molecules (such as inducers, inhibitors, or nucleic acid molecules) by virtue of physical materials (such as nanoparticles) or biological materials (such as peptides) to skin topically may obtain clinical benefits in immune-related skin diseases. Moreover, developing autophagy-related gene product-based biomarkers may be promising to diagnose immune-related skin diseases.

Natural medicine combined with nanobased topical delivery systems: a new strategy to treat psoriasis

Psoriasis, an autoimmune inflammatory skin disorder, is one of the commonest immune-mediated disease conditions affecting individuals globally. At the moment, the conventional methods applied against psoriasis treatment have various drawbacks involving limited efficacy, skin irritation, immunosuppression, etc. Therefore, it is important for scientists to find a more potent and alternative drug approach towards psoriasis therapeutics. Natural medicine still remains an important source for new drug discovery due to its therapeutical significance in various drug administration routes. However, the traditional formulation of topical therapies for psoriasis is limited in efficacy, which limits the use of natural medicine. Based on the aforementioned limitations, the use of nanocarriers in preparation of these topical herbal products could be tremendously beneficial in enhancing the efficacy of topical medications. Growing pieces of evidence have proposed that the utilization of nanocarriers in transdermal preparation as a prospective technique, with regards to better potency, directs drug absorption to site of action, and minimum toxicity effect respectively. In the course of this review, we emphasized the pathological mechanism of psoriasis, natural medicine formula, active components of natural medicine, and nanopreparations used in the treatment of psoriasis.

The paeonol target gene autophagy-related 5 has a potential therapeutic value in psoriasis treatment

Background

Paeonol is a potent therapy for psoriasis. This study aimed to screen out paeonol-targeted genes in psoriasis and validate the potential of using paeonol for the management of psoriasis.

Methods

Microarray datasets were obtained from the Gene Expression Omnibus. The differentially expressed genes (DEGs) in the lesional skin samples and the overlapping genes between DEGs and paeonol- and psoriasis-related genes were defined as potential targets for psoriasis. After being treated with si-ATG5 and pc-ATG5, human HaCaT cells were treated with 100 ng/ml IL-22 and 10 ng/ml TNF-α with and without paeonol. Cell proliferation, apoptosis, and expression of interleukin (IL)-6, IL-1β, Beclin 1, ATG5, and p62 in HaCaT cells were determined using ESLIA, PCR, and Western blot analysis.

Results

A total of 779 DEGs were identified in the lesional skin samples compared with the non-lesional tissues. The autophagy-related 5 (ATG5) gene was the only gene that overlapped between the DEGs and genes related to paeonol and psoriasis. Cell proliferation, inflammatory cytokines (IL-6 and IL-1β), and ATG5 expression were increased in IL-22/TNF-α-stimulated HaCaT (model) cells compared with control. Paeonol treatment rescued all changes. si-ATG5 transfection increased inflammation and apoptosis in model cells compared with controls. pc-ATG5 prevented IL-22/TNF-α-induced changes in HaCaT cells. Also, si-ATG5 decreased p62 and Beclin 1 proteins, while pc-ATG5 increased them both.

Conclusions

ATG5-dependent autophagy plays a crucial role in psoriasis. The ATG5 gene might be a therapeutic target for the management of in vitro psoriasis.

Regulating the Polarization of Macrophages: A Promising Approach to Vascular Dermatosis

Macrophages, a kind of innate immune cells, derive from monocytes in circulation and play a crucial role in the innate and adaptive immunity. Under the stimulation of the signals from local microenvironment, macrophages generally tend to differentiate into two main functional phenotypes depending on their high plasticity and heterogeneity, namely, classically activated macrophage (M1) and alternatively activated macrophage (M2). This phenomenon is often called macrophage polarization. In pathological conditions, chronic persistent inflammation could induce an aberrant response of macrophage and cause a shift in their phenotypes. Moreover, this shift would result in the alteration of macrophage polarization in some vascular dermatoses; e.g., an increase in proinflammatory M1 emerges from Behcet's disease (BD), psoriasis, and systemic lupus erythematosus (SLE), whereas an enhancement in anti-inflammatory M2 appears in infantile hemangioma (IH). Individual polarized phenotypes and their complicated cytokine networks may crucially mediate in the pathological processes of some vascular diseases (vascular dermatosis in particular) by activation of T cell subsets (such as Th1, Th2, Th17, and Treg cells), deterioration of oxidative stress damage, and induction of angiogenesis, but the specific mechanism remains ambiguous. Therefore, in this review, we discuss the possible role of macrophage polarization in the pathological processes of vascular skin diseases. In addition, it is proposed that regulation of macrophage polarization may become a potential strategy for controlling these disorders.

Autophagy-based unconventional secretion of HMGB1 by keratinocytes plays a pivotal role in psoriatic skin inflammation

The precise mechanism through which macroautophagy/autophagy affects psoriasis is poorly understood. Here, we found that keratinocyte (KC) autophagy, which was positively correlated with psoriatic severity in patients and mouse models and could be inhibited by mitogen-activated protein kinase (MAPK) family inactivation. The impairment of autophagic flux alleviated psoriasisform inflammation. We also found that an autophagy-based unconventional secretory pathway (autosecretion) dependent on ATG5 (autophagy related 5) and GORASP2 (golgi reassembly stacking protein 2) promoted psoriasiform KC inflammation. Moreover, the alarmin HMGB1 (high mobility group box 1) was more effective than other autosecretory proteins in regulating psoriasiform cutaneous inflammation. HMGB1 neutralization in autophagy-efficient KCs eliminated the differences in psoriasiform inflammation between Krt14^+/+-Atg5^f/f KCs and Krt14^Cre/+-atg5^f/f KCs, and conversely, recombinant HMGB1 almost completely restored psoriasiform inflammation in Krt14^Cre/+-atg5^f/f KCs in vivo. These results suggest that HMGB1-associated autosecretion plays a pivotal role in cutaneous inflammation. Finally, we demonstrated that Krt14^Cre/+-hmgb1^f/f mice displayed attenuated psoriatic inflammation due to the essential crosstalk between KC-specific HMGB1-associated autosecretion and γδT cells. Thus, this study uncovered a novel autophagy mechanism in psoriasis pathogenesis, and the findings imply the clinical significance of investigating and treating psoriasis.Abbreviations: 3-MA: 3-methyladenine; ACTB: actin beta; AGER: advanced glycosylation end-product specific receptor; Anti-HMGB1: anti-HMGB1 neutralizing antibody; Anti-IL18: anti-IL18 neutralizing antibody; Anti-IL1B: anti-IL1B neutralizing antibody; ATG5: autophagy related 5; BAF: bafilomycin A₁; BECN1: beclin 1; CASP1: caspase 1; CCL: C-C motif chemokine ligand; CsA: cyclosporine A; ctrl shRNA: lentivirus harboring shRNA against control; CXCL: C-X-C motif chemokine ligand; DCs: dendritic cells; DMEM: dulbecco's modified Eagle's medium; ELISA: enzyme-linked immunosorbent assay; EM: electron microscopy; FBS: fetal bovine serum; GORASP2 shRNA: lentivirus harboring shRNA against GORASP2; GORASP2/GRASP55: golgi reassembly stacking protein 2; GR1: a composite epitope between LY6 (lymphocyte antigen 6 complex) locus C1 and LY6 locus G6D antigens; H&E: hematoxylin and eosin; HMGB1: high mobility group box 1; HMGB1 shRNA: lentivirus harboring shRNA against HMGB1; IFNG/IFN-γ: interferon gamma; IL17A: interleukin 17A; IL18: interleukin 18; IL1A/IL-1α: interleukin 1 alpha; IL1B/IL-1β: interleukin 1 beta; IL22/IL-22: interleukin 22; IL23A: interleukin 23 subunit alpha; IL23R: interleukin 23 receptor; IMQ: imiquimod; ITGAM/CD11B: integrin subunit alpha M; ITGAX/CD11C: integrin subunit alpha X; IVL: involucrin; KC: keratinocyte; KD: knockdown; KO: knockout; Krt14^+/+-Atg5^f/f mice: mice bearing an Atg5 flox allele, in which exon 3 of the Atg5 gene is flanked by two loxP sites; Krt14^+/+-Hmgb1^f/f: mice bearing an Hmgb1 flox allele, in which exon 2 to 4 of the Hmgb1 gene is flanked by two loxP sites; Krt14^Cre/+-atg5^f/f mice: keratinocyte-specific atg5 knockout mice generated by mating Atg5-floxed mice with mice expressing Cre recombinase under the control of the promoter of Krt4; Krt14^Cre/+-hmgb1^f/f mice: keratinocyte-specific hmgb1 knockout mice generated by mating Hmgb1-floxed mice with mice expressing Cre recombinase under the control of the promoter of Krt14; Krt14-Vegfa mice: mice expressing 164-amino acid Vegfa splice variant recombinase under the control of promoter of Krt14; LAMP1: lysosomal associated membrane protein 1; LDH: lactate dehydrogenase; LORICRIN: loricrin cornified envelope precursor protein; M5: TNF, IL1A, IL17A, IL22 and OSM in combination; MAP1LC3/LC3: microtubule associated protein 1 light chain 3; MAPK: mitogen-activated protein kinase; MKI67: marker of proliferation Ki-67; MTT: thiazolyl blue tetrazolium bromide; NFKB/NF-κB: nuclear factor kappa B; NHEKs: primary normal human epidermal keratinocytes; NS: not significant; OSM: oncostatin M; PASI: psoriasis area and severity index; PtdIns3K: class III phosphatidylinositol 3-kinase; qRT-PCR: quantitative RT-PCR; RELA/p65: RELA proto-oncogene, NF-kB subunit; rHMGB1: recombinant HMGB1; rIL18: recombinant interleukin 18; rIL1B: recombinant interleukin 1 beta; S100A: S100 calcium binding protein A; SQSTM1/p62: sequestosome 1; T17: IL17A-producing T; TCR: T-cell receptor; tcrd KO mice: tcrd (T cell receptor delta chain) knockout mice, which show deficient receptor expression in all adult lymphoid and epithelial organs; TLR: toll-like receptor; TNF/TNF-α: tumor necrosis factor; WOR: wortmannin; WT: wild-type; γδT17 cells: IL17A-producing γδ T cells.

Role and mechanism of matrine alone and combined with acitretin for HaCaT cells and psoriasis-like murine models

BACKGROUND

Acitretin and matrine have been used in the treatment of psoriasis in China. This study was designed to investigate the role and related mechanisms of matrine alone and in combination with acitretin in the treatment of psoriasis in vitro and in vivo.

METHODS

HaCaT cells were treated with matrine at different concentrations of 0 (blank control), 0.2, 0.4, 0.8, and 1.6 mg/mL for 24, 48, 72 h, respectively. 3-(4,5-dimethylthiazol-2-yl)-5-(3-carboxymethoxyphenyl)-2-(4-sulfophenyl)-2H-tetrazolium cell viability assay was used to assess the growth and proliferation of HaCaT cells. Cell cycle and apoptosis were detected by flow cytometry. Expression of protein was detected by Western blotting. Autophagy was observed by transmission electron microscopy. Then HaCaT cells were assigned to normal saline (NS) control group, matrine (0.4 mg/mL) group, acitretin (10 μmol/L) group, and matrine plus acitretin group, and the above methods were repeated. In animal experiments, the cumulative score (erythema, scaling, thickening) as a measure of the severity of inflammation was used to measure the skin performance of mice after treated with matrine 50 mg/kg, acitretin 4.5 mg/kg or combination of the two drugs on the psoriasis-like mouse models, respectively. Pathological findings of the lesions were observed, and the protein expressions in the lesions were detected by immunohistochemistry.

RESULTS

Cell proliferation inhibition was seen in HaCaT cells with treatment of matrine in a dose- and time-dependent manner (P < 0.01, respectively). Cell cycle G0/G1 phase arrest was observed in a dose-dependent way (P < 0.01). The expression of p21 (P < 0.05), LC3II/I (P < 0.01), and Beclin 1 (P < 0.01) increased and the expression of cyclin D1 (P < 0.05) decreased with increasing doses of matrine. Compared with the blank control, more autophagosomes were seen in HaCaT cells treated with matrine at 0.4 mg/mL by transmission electron microscopy (2.667 ± 1.202 vs. 21.33 ± 1.453, t = 9.899, P < 0.01). Cell proliferation inhibition and degree of the G0/G1 phase arrest was significantly higher in matrine plus acitretin group than those in matrine, acitretin, or the NS control group (P < 0.01, respectively). Compared with matrine or acitretin group, the expression of p21 (P < 0.05, P < 0.05) and LC3II/I (P < 0.01, P < 0.05) in matrine plus acitretin group increased significantly and the expression of cyclin D1 (P < 0.01, P < 0.05) and p62 (P < 0.05, P < 0.05) was reduced significantly. Compared with matrine or acitretin, matrine plus acitretin significantly down-regulated the phosphorylation of phosphoinositide 3-kinase (PI3K)/protein kinase B (Akt)/mammalian target of rapamycin (mTOR) pathway (P < 0.05) and its downstream p-p70S6K (P < 0.05). In addition, the cumulative score of mice in the matrine plus acitretin group was significantly better than that in the matrine or acitretin group (1.480 ± 0.230 vs. 2.370 ± 0.241, P < 0.01; 1.480 ± 0.230 vs. 2.888 ± 0.341, P < 0.01). The expression of LC3 protein in the matrine plus acitretin group was also higher than that in the matrine, acitretin, or the NS control group (P < 0.05, respectively).

CONCLUSIONS

Matrine has therapeutic potentials for psoriasis. Matrine and acitretin show synergistic effect via cell cycle arrest and autophagy induction by PI3K/Akt/mTOR pathway.