Reactive oxygen species prevent imiquimod-induced psoriatic dermatitis through enhancing regulatory T cell function

Tumor microenvironment regulation by reactive oxygen species-mediated inflammasome activation

Tumor microenvironment (TME) is composed of diverse cell types whose interactions, both direct and indirect, significantly influence tumorigenesis and therapeutic outcomes. Within TME, reactive oxygen species (ROS) are produced by various cells and exhibit a dual role: moderate ROS levels promote tumor initiation and progression, whereas excessive levels induce cancer cell death, influencing the efficacy of anticancer therapies. Inflammasomes, cytosolic multiprotein complexes, are pivotal in multiple stages of tumorigenesis and play a crucial role in establishing the inflammatory TME. By releasing cytokines such as IL-1β and IL-18, inflammasomes contribute to immune cell recruitment and sustain a chronic inflammatory state that supports tumor growth. ROS are critical regulators of inflammasome activation, with the impact of ROS-mediated activation differing across cell types, leading to distinct influences on tumor progression and therapeutic responses. This review explores how ROS drive inflammasome activation in various TME-associated cells and the reciprocal ROS generation induced by inflammasomes, examining their multifaceted impact on tumorigenesis and therapeutic efficacy. By elucidating the complex interplay between ROS and inflammasomes in TME, we provide insights into potential therapeutic approaches that could modulate cancer progression and enhance treatment outcomes.

TMED4 facilitates regulatory T cell suppressive function via ROS homeostasis in tumor and autoimmune mouse models

Endoplasmic reticulum stress (ERS) plays crucial roles in maintaining Treg stability and function, yet the underlying mechanism remains largely unexplored. Here, we demonstrate that (Tmed4ΔTreg) mice with Treg-specific KO of ERS-related protein transmembrane p24 trafficking protein 4 (TMED4) had more Tregs with impaired Foxp3 stability, Treg signatures, and suppressive activity, which led to T cell hyperactivation and an exacerbated inflammatory phenotype and boosted antitumor immunity in mice. Mechanistically, loss of Tmed4 caused defects in ERS and a nuclear factor erythroid 2-related factor 2-related (NRF2-related) antioxidant response, which resulted in excessive ROS that reduced the Foxp3 stability and suppressive function of Tregs in an IRE1α/XBP1 axis-dependent manner. The abnormalities could be effectively rescued by the ROS scavenger, NRF2 inducer, or by forcible expression of IRE1α. Moreover, TMED4 suppressed IRE1α proteosome degradation via the ER-associated degradation (ERAD) system including the ER chaperone binding immunoglobulin protein (BIP). Our study reveals that TMED4 maintained the stability of Tregs and their suppressive function through IRE1α-dependent ROS and the NRF2-related antioxidant response.

Eucalyptus oil nanoemulsion for enhanced skin deposition of fluticasone propionate in psoriatic plaques: A combinatorial anti-inflammatory effect to suppress implicated cytokines

Psoriasis is a chronic inflammatory skin disease that affects patients' quality of life. This study aimed to enhance the efficacy of topical application of fluticasone propionate (FP) using a eucalyptus oil-based nanoemulsion, an oil possessing anti-inflammatory activity and extracted from the leaves, fruits, and buds of Eucalyptus globulus or Eucalyptus maidenii, to improve the skin deposition of FP and aid its anti-inflammatory effect. Box-Behnken design was employed to optimize NE formulations, which were characterized for globule size, zeta potential, polydispersity index, rheological behavior, microscopic morphology, ex vivo skin permeation/deposition, and in vivo efficacy using imiquimod-induced psoriatic lesions. The optimized formulation depicted a droplet size of 188 ± 22.4 nm, a zeta potential of -17.63 ± 1.66 mV, and a viscosity of 204.9 mPa s. In addition to the increased FP retention in different skin layers caused by the NE and the reduced PASI score compared to the marketed cream, the levels of inflammatory cytokines IL-1α, IL-6, IL17a were markedly lowered, indicating the improved anti-psoriatic curable efficacy of the optimized formulation in comparison to the FP-marketed product.

Neutrophil exhaustion and impaired functionality in psoriatic arthritis patients

Background

Neutrophils (polymorphonuclear leukocytes, PMNs) are the most abundant subtype of white blood cells and are among the main actors in the inflammatory response. Psoriatic arthritis (PsA) is a chronic inflammatory disease affecting both the axial and peripheral joints. Typically associated with psoriasis, PsA can also affect multiple systems and organs, including the nails and entheses. Despite the involvement of PMNs in PsA, their specific role in the disease remains poorly understood. This study aimed to characterize the biological functions of PMNs and neutrophil-related mediators in PsA patients.

Materials and methods

31 PsA patients and 22 healthy controls (HCs) were prospectively recruited. PMNs were isolated from peripheral blood and subjected to in vitro stimulation with lipopolysaccharide (LPS), N-Formylmethionyl-leucyl-phenylalanine (fMLP), tumor necrosis factor (TNF), phorbol 12-myristate 13-acetate (PMA), or control medium. Highly purified peripheral blood PMNs (>99%) were evaluated for activation status, reactive oxygen species (ROS) production, phagocytic activity, granular enzyme and neutrophil extracellular traps (NETs) release. Serum levels of matrix metalloproteinase-9 (MMP-9), myeloperoxidase (MPO), TNF, interleukin 23 (IL-23), and interleukin 17 (IL-17) were measured by ELISA. Serum Citrullinated histone H3 (CitH3) was measured as a NET biomarker.

Results

Activated PMNs from PsA patients displayed reduced activation, decreased ROS production, and impaired phagocytic activity upon stimulation with TNF, compared to HCs. PMNs from PsA patients also displayed reduced granular enzyme (MPO) and NET release. Serum analyses revealed elevated levels of MMP-9, MPO, TNF, IL-23, IL-17, and CitH3 in PsA patients compared to HCs. Serum CitH3 levels positively correlated with MPO and TNF concentrations, and IL-17 concentrations were positively correlated with IL-23 levels in PsA patients. These findings indicate that PMNs from PsA patients show reduced in vitro activation and function, and an increased presence of neutrophil-derived mediators (MMP-9, MPO, TNF, IL-23, IL-17, and CitH3) in their serum.

Conclusions

Taken together, our findings suggest that PMNs from PsA patients exhibit an "exhausted" phenotype, highlighting their plasticity and multifaceted roles in PsA pathophysiology.

Energy competition remodels the metabolic glucose landscape of psoriatic epidermal cells

Rationale: Skin cells actively metabolize nutrients to ensure cell proliferation and differentiation. Psoriasis is an immune-disorder-related skin disease with hyperproliferation in epidermal keratinocytes and is increasingly recognized to be associated with metabolic disturbance. However, the metabolic adaptations and underlying mechanisms of epidermal hyperproliferation in psoriatic skin remain largely unknown. Here, we explored the role of metabolic competition in epidermal cell proliferation and differentiation in psoriatic skin. Methods: Bulk- and single-cell RNA-sequencing, spatial transcriptomics, and glucose uptake experiments were used to analyze the metabolic differences in epidermal cells in psoriasis. Functional validation in vivo and in vitro was done using imiquimod-like mouse models and inflammatory organoid models. Results: We observed the highly proliferative basal cells in psoriasis act as the winners of the metabolic competition to uptake glucose from suprabasal cells. Using single-cell metabolic analysis, we found that the "winner cells" promote OXPHOS pathway upregulation by COX7B and lead to increased ROS through glucose metabolism, thereby promoting the hyperproliferation of basal cells in psoriasis. Also, to prevent toxic damage from ROS, basal cells activate the glutathione metabolic pathway to increase their antioxidant capacity to assist in psoriasis progression. We further found that COX7B promotes psoriasis development by modulating the activity of the PPAR signaling pathway by bulk RNA-seq analysis. We also observed glucose starvation and high expression of SLC7A11 that causes suprabasal cell disulfide stress and affects the actin cytoskeleton, leading to immature differentiation of suprabasal cells in psoriatic skin. Conclusion: Our study demonstrates the essential role of cellular metabolic competition for skin tissue homeostasis.

Macrophage Functions in Psoriasis: Lessons from Mouse Models

Psoriasis is a systemic autoimmune/autoinflammatory disease that can be well studied in established mouse models. Skin-resident macrophages are classified into epidermal Langerhans cells and dermal macrophages and are involved in innate immunity, orchestration of adaptive immunity, and maintenance of tissue homeostasis due to their ability to constantly shift their phenotype and adapt to the current microenvironment. Consequently, both macrophage populations play dual roles in psoriasis. In some circumstances, pro-inflammatory activated macrophages and Langerhans cells trigger psoriatic inflammation, while in other cases their anti-inflammatory stimulation results in amelioration of the disease. These features make macrophages interesting candidates for modern therapeutic strategies. Owing to the significant progress in knowledge, our review article summarizes current achievements and indicates future research directions to better understand the function of macrophages in psoriasis.

Roles of reactive oxygen species in inflammation and cancer

Reactive oxygen species (ROS) constitute a spectrum of oxygenic metabolites crucial in modulating pathological organism functions. Disruptions in ROS equilibrium span various diseases, and current insights suggest a dual role for ROS in tumorigenesis and the immune response within cancer. This review rigorously examines ROS production and its role in normal cells, elucidating the subsequent regulatory network in inflammation and cancer. Comprehensive synthesis details the documented impacts of ROS on diverse immune cells. Exploring the intricate relationship between ROS and cancer immunity, we highlight its influence on existing immunotherapies, including immune checkpoint blockade, chimeric antigen receptors, and cancer vaccines. Additionally, we underscore the promising prospects of utilizing ROS and targeting ROS modulators as novel immunotherapeutic interventions for cancer. This review discusses the complex interplay between ROS, inflammation, and tumorigenesis, emphasizing the multifaceted functions of ROS in both physiological and pathological conditions. It also underscores the potential implications of ROS in cancer immunotherapy and suggests future research directions, including the development of targeted therapies and precision oncology approaches. In summary, this review emphasizes the significance of understanding ROS-mediated mechanisms for advancing cancer therapy and developing personalized treatments.

In adult X-CGD patients, regulatory T cells are expanded while activated T cells display a NOX2-independent ROS increase

The X-linked chronic granulomatous disease (X-CGD), a rare genetic disease characterised by recurrent infections, is caused by mutations of NOX2. Significant proportions of X-CGD patients display signs of immune dysregulation. Regulatory T cells (Tregs) are CD4+T lymphocytes that expand in active inflammation and prevent autoimmune disorders. Here we asked whether X-CGD is associated to Treg dysfunctions in adult patients. To this aim, the frequency of Tregs was analysed through intracellular flow cytometry in a cohort of adult X-CGD patients, carriers and controls. We found that Tregs were significantly expanded and activated in blood of adult X-CGD patients, and this was associated with activation of conventional CD4+T cells (Tconvs). T cell activation was characterised by accumulation of intracellular ROS, not derived from NOX2 but likely produced by cellular metabolism. The higher TNF production by Tconvs in X-CGD patients might contribute to the expansion of Tregs through the TNFR2 receptor. In summary, our data indicate that Tregs expand in adult X-CGD in response to immune activation, and that the increase of NOX2-independent ROS content is a feature of activated T cells.

Ursolic Acid Formulations Effectively Induce Apoptosis and Limit Inflammation in the Psoriasis Models In Vitro

Psoriasis, a prevalent inflammatory skin disorder affecting a significant percentage of the global population, poses challenges in its management, necessitating the exploration of novel cost-effective and widely accessible therapeutic options. This study investigates the potential of ursolic acid (UA), a triterpenoid known for its anti-inflammatory and pro-apoptotic properties, in addressing psoriasis-related inflammation and keratinocyte hyperproliferation. The research involved in vitro models employing skin and immune cells to assess the effects of UA on psoriasis-associated inflammation. The presented research demonstrates the limiting effects of UA on IL-6 and IL-8 production in response to the inflammatory stimuli and limiting effects on the expression of psoriatic biomarkers S100A7, S100A8, and S100A9. Further, the study reveals promising outcomes, demonstrating UA's ability to mitigate inflammatory responses and hyperproliferation of keratinocytes by the induction of non-inflammatory apoptosis, as well as a lack of the negative influence on other cell types, including immune cells. Considering the limitations of UA's poor solubility, hybrid systems were designed to enhance its bioavailability and developed as hybrid nano-emulsion and bi-gel topical systems to enhance bioavailability and effectiveness of UA. One of them in particular-bi-gel-demonstrated high effectiveness in limiting the pathological response of keratinocytes to pro-psoriatic stimulation; this was even more prominent than with ursolic acid alone. Our results indicate that topical formulations of ursolic acid exhibit desirable anti-inflammatory activity in vitro and may be further employed for topical psoriasis treatment.

Metabolic advantages of regulatory T cells dictated by cancer cells

Cancer cells employ glycolysis for their survival and growth (the "Warburg effect"). Consequently, surrounding cells including immune cells in the tumor microenvironment (TME) are exposed to hypoglycemic, hypoxic, and low pH circumstances. Since effector T cells depend on the glycolysis for their survival and functions, the metabolically harsh TME established by cancer cells is unfavorable, resulting in the impairment of effective antitumor immune responses. By contrast, immunosuppressive cells such as regulatory T (Treg) cells can infiltrate, proliferate, survive, and exert immunosuppressive functions in the metabolically harsh TME, indicating the different metabolic dependance between effector T cells and Treg cells. Indeed, some metabolites that are harmful for effector T cells can be utilized by Treg cells; lactic acid, a harmful metabolite for effector T cells, is available for Treg cell proliferation and functions. Deficiency of amino acids such as tryptophan and glutamine in the TME impairs effector T cell activation but increases Treg cell populations. Furthermore, hypoxia upregulates fatty acid oxidation via hypoxia-inducible factor 1α (HIF-1α) and promotes Treg cell migration. Adenosine is induced by the ectonucleotidases CD39 and CD73, which are strongly induced by HIF-1α, and reportedly accelerates Treg cell development by upregulating Foxp3 expression in T cells via A2AR-mediated signals. Therefore, this review focuses on the current views of the unique metabolism of Treg cells dictated by cancer cells. In addition, potential cancer combination therapies with immunotherapy and metabolic molecularly targeted reagents that modulate Treg cells in the TME are discussed to develop "immune metabolism-based precision medicine".

Applications of cold atmospheric plasma in immune-mediated inflammatory diseases via redox homeostasis: evidence and prospects

As a representative technology in plasma medicine, cold atmospheric plasma (CAP) has beneficial outcomes in surface disinfection, wound repair, tissue regeneration, solid tumor therapy. Impact on immune response and inflammatory conditions was also observed in the process of CAP treatment. Relevant literatures were collected to assess efficacy and summarize possible mechanisms of the innovation. CAP mediates alteration in local immune microenvironment mainly through two ways. One is to down-regulate the expression level of several cytokines, impeding further conduction of immune or inflammatory signals. Intervening the functional phenotype of cells through different degree of oxidative stress is the other approach to manage the immune-mediated inflammatory disorders. A series of preclinical and clinical studies confirmed the therapeutic effect and side effects free of CAP. Moreover, several suggestions proposed in this manuscript might help to find directions for future investigation.

The role of transcription factors in shaping regulatory T cell identity

Forkhead box protein 3-expressing (FOXP3+) regulatory T cells (Treg cells) suppress conventional T cells and are essential for immunological tolerance. FOXP3, the master transcription factor of Treg cells, controls the expression of multiples genes to guide Treg cell differentiation and function. However, only a small fraction (<10%) of Treg cell-associated genes are directly bound by FOXP3, and FOXP3 alone is insufficient to fully specify the Treg cell programme, indicating a role for other accessory transcription factors operating upstream, downstream and/or concurrently with FOXP3 to direct Treg cell specification and specialized functions. Indeed, the heterogeneity of Treg cells can be at least partially attributed to differential expression of transcription factors that fine-tune their trafficking, survival and functional properties, some of which are niche-specific. In this Review, we discuss the emerging roles of accessory transcription factors in controlling Treg cell identity. We specifically focus on members of the basic helix-loop-helix family (AHR), basic leucine zipper family (BACH2, NFIL3 and BATF), CUT homeobox family (SATB1), zinc-finger domain family (BLIMP1, Ikaros and BCL-11B) and interferon regulatory factor family (IRF4), as well as lineage-defining transcription factors (T-bet, GATA3, RORγt and BCL-6). Understanding the imprinting of Treg cell identity and specialized function will be key to unravelling basic mechanisms of autoimmunity and identifying novel targets for drug development.

4-Octyl itaconate inhibits inflammation to attenuate psoriasis as an agonist of oxeiptosis

Psoriasis is a highly prevalent chronic disease associated with a substantial social and economic burden. Oxeiptosis is a programmed cell death that occurs when cells are in a state of high oxidative stress, which has a potent anti-inflammatory effect. However, there is still no research on oxeiptosis in psoriasis, and the agonists or antagonists of oxeiptosis remain an unclear field. Here, we found that oxeiptosis of keratinocytes was inhibited in psoriasis lesions. KEAP1, as the upstream molecular component of oxeiptosis, is highly expressed in psoriasis lesions. Knockdown of KEAP1 in HaCaT cells caused oxeiptosis in the condition of M5 cocktail stimulation. Next, we found that the cell-permeable derivative of itaconate, 4-octylitaconate (OI) promoted oxeiptosis of keratinocytes by inhibiting KEAP1 and then activating PGAM5 which are two upstream molecular components of oxeiptosis. At the same time, OI can reduce the expression of inflammatory cytokines induced by M5 cocktail stimulation in vitro. Similarly, we found that OI can alleviate IMQ-induced psoriatic lesions in mice and downregulate the levels of inflammatory cytokines in psoriatic lesions. In summary, our findings suggest that oxeiptosis of keratinocytes was inhibited in psoriasis and OI can significantly inhibit inflammation and alleviate psoriasis as an agonist of oxeiptosis, indicating that oxeiptosis may be involved in regulating the progression of psoriasis, which may provide new therapeutic targets for psoriasis treatment.

β-Galactosidase-activated nitroxyl (HNO) donors provide insights into redox cross-talk in senescent cells

The cross-talk among reductive and oxidative species (redox cross-talk), especially those derived from sulfur, nitrogen and oxygen, influence several physiological processes including aging. One major hallmark of aging is cellular senescence, which is associated with chronic systemic inflammation. Here, we report a chemical tool that generates nitoxyl (HNO) upon activation by β-galactosidase, an enzyme that is over-expressed in senescent cells. In a radiation-induced senescence model, the HNO donor suppressed reactive oxygen species (ROS) in a hydrogen sulfide (H2S)-dependent manner. Hence, the newly developed tool provides insights into redox cross-talk and establishes the foundation for new interventions that modulate levels of these species to mitigate oxidative stress and inflammation.

A reactive oxygen species-related signature to predict prognosis and aid immunotherapy in clear cell renal cell carcinoma

Background

Clear cell renal cell carcinoma (ccRCC) is a malignant disease containing tumor-infiltrating lymphocytes. Reactive oxygen species (ROS) are present in the tumor microenvironment and are strongly associated with cancer development. Nevertheless, the role of ROS-related genes in ccRCC remains unclear.

Methods

We describe the expression patterns of ROS-related genes in ccRCC from The Cancer Genome Atlas and their alterations in genetics and transcription. An ROS-related gene signature was constructed and verified in three datasets and immunohistochemical staining (IHC) analysis. The immune characteristics of the two risk groups divided by the signature were clarified. The sensitivity to immunotherapy and targeted therapy was investigated.

Results

Our signature was constructed on the basis of glutamate-cysteine ligase modifier subunit (GCLM), interaction protein for cytohesin exchange factors 1 (ICEF1), methionine sulfoxide reductase A (MsrA), and strawberry notch homolog 2 (SBNO2) genes. More importantly, protein expression levels of GCLM, MsrA, and SBNO2 were detected by IHC in our own ccRCC samples. The high-risk group of patients with ccRCC suffered lower overall survival rates. As an independent predictor of prognosis, our signature exhibited a strong association with clinicopathological features. An accurate nomogram for improving the clinical applicability of our signature was constructed. Gene Ontology and Kyoto Encyclopedia of Genes and Genomes analyses showed that the signature was closely related to immune response, immune activation, and immune pathways. The comprehensive results revealed that the high-risk group was associated with high infiltration of regulatory T cells and CD8+ T cells and more benefited from targeted therapy. In addition, immunotherapy had better therapeutic effects in the high-risk group.

Conclusion

Our signature paved the way for assessing prognosis and developing more effective strategies of immunotherapy and targeted therapy in ccRCC.

Neutrophils inhibit γδ T cell functions in the imiquimod-induced mouse model of psoriasis

Background

Psoriasis is a chronic skin disease associated with deregulated interplays between immune cells and keratinocytes. Neutrophil accumulation in the skin is a histological feature that characterizes psoriasis. However, the role of neutrophils in psoriasis onset and development remains poorly understood.

Methods

In this study, we utilized the model of psoriasiform dermatitis, caused by the repeated topical application of an imiquimod containing cream, in neutrophil-depleted mice or in mice carrying impairment in neutrophil functions, including p47phox -/- mice (lacking a cytosolic subunit of the phagocyte nicotinamide adenine dinucleotide phosphate - NADPH - oxidase) and Sykfl/fl MRP8-cre+ mice (carrying the specific deletion of the Syk kinase in neutrophils only), to elucidate the specific contribution of neutrophils to psoriasis development.

Results

By analyzing disease development/progression in neutrophil-depleted mice, we now report that neutrophils act as negative modulators of disease propagation and exacerbation by inhibiting gammadelta T cell effector functions via nicotinamide adenine dinucleotide phosphate (NADPH) oxidase-mediated reactive oxygen species (ROS) production. We also report that Syk functions as a crucial molecule in determining the outcome of neutrophil and γδ T cell interactions. Accordingly, we uncover that a selective impairment of Syk-dependent signaling in neutrophils is sufficient to reproduce the enhancement of skin inflammation and γδ T cell infiltration observed in neutrophil-depleted mice.

Conclusions

Overall, our findings add new insights into the specific contribution of neutrophils to disease progression in the IMQ-induced mouse model of psoriasis, namely as negative regulatory cells.

A double-edged sword: ROS related therapies in the treatment of psoriasis

In the onset and progression of psoriasis, redox imbalance is a vital factor. It's widely accepted that too much reactive oxygen species (ROS) always make psoriasis worse. Recent research, however, has shown that the accumulation of ROS is not entirely detrimental, as it helps reduce psoriasis lesions by inhibiting epidermal proliferation and keratinocyte death. As a result, ROS appears to have two opposing effects on the treatment of psoriasis. In this review, the current ROS-related therapies for psoriasis, including basic and clinical research, are presented. Additionally, the design and therapeutic benefits of various drug delivery systems and therapeutic approaches are examined, and a potential balance between anti-oxidative stress and ROS accumulation is also trying to be investigated.

The role of polyamine metabolism in remodeling immune responses and blocking therapy within the tumor immune microenvironment

The study of metabolism provides important information for understanding the biological basis of cancer cells and the defects of cancer treatment. Disorders of polyamine metabolism is a common metabolic change in cancer. With the deepening of understanding of polyamine metabolism, including molecular functions and changes in cancer, polyamine metabolism as a new anti-cancer strategy has become the focus of attention. There are many kinds of polyamine biosynthesis inhibitors and transport inhibitors, but not many drugs have been put into clinical application. Recent evidence shows that polyamine metabolism plays essential roles in remodeling the tumor immune microenvironment (TIME), particularly treatment of DFMO, an inhibitor of ODC, alters the immune cell population in the tumor microenvironment. Tumor immunosuppression is a major problem in cancer treatment. More and more studies have shown that the immunosuppressive effect of polyamines can help cancer cells to evade immune surveillance and promote tumor development and progression. Therefore, targeting polyamine metabolic pathways is expected to become a new avenue for immunotherapy for cancer.

Metformin Inhibits HaCaT Cell Proliferation Under Hyperlipidemia Through Reducing Reactive Oxygen Species via FOXO3 Activation

Purpose

Metformin (MET) has been proved to be effective for the treatment of psoriasis. The mechanisms of its action under the hyperlipidemia have yet to be fully elucidated. Here, we investigated the effect of metformin on the cell proliferation induced by hyperlipidemia and the underlying mechanism in immortalized human keratinocyte cell line (HaCat).

Methods

Wild-type or FOXO3 knockdown HaCat cells were treated with free fatty acids (FFA) for 10 days and then co-treated with metformin for another 4 days. Triglyceride (TG) level, cell viability, proliferation, apoptosis, antioxidant enzymes, reactive oxygen species (ROS) levels, as well as the transcription activity of FOXO3 were analyzed.

Results

Metformin decreased HaCaT cell proliferation and induced cell apoptosis after FFA treatment. Metformin was found to significantly increase the expressions and the activities of superoxide dismutase (SOD) as well as catalase (CAT), and reduced the reactive oxygen species (ROS) level. Metformin significantly promoted the autophagy and increase FOXO3 protein level in the nucleus under hyperlipidemia. However, all of the effects from metformin were partially blocked by FOXO3 knockdown.

Conclusion

This study demonstrated that under the hyperlipidemia, metformin has significant antiproliferation and proapoptosis effects by reducing ROS level as well as increasing autophagy. All of these effects from metformin were through FOXO3-dependent pathway.

Multi-faced roles of reactive oxygen species in anti-tumor T cell immune responses and combination immunotherapy

T cells play a central role in anti-tumor immunity, and reactive oxygen species (ROS) lie at the crossroad on the anti-tumor T cell responses. To activate efficient T cell immunity, a moderate level of ROS is needed, however, excessive ROS would cause toxicity to the T cells, because the improper level leads to the formation and maintenance of an immunosuppressive tumor microenvironment. Up to date, strategies that modulate ROS, either increasing or decreasing, have been widely investigated. Some of them are utilized in anti-tumor therapies, showing inevitable impacts on the anti-tumor T cell immunity with both obverse and reverse sides. Herein, the impacts of ROS-increasing and ROS-decreasing treatments on the T cell responses in the tumor microenvironment are reviewed and discussed. At the same time, outcomes of combination immunotherapies are introduced to put forward inspirations to unleash the potential of immunotherapies.

Treatment efficacy of Thunbergia laurifolia, Curcuma longa, Garcinia mangostana, and Andrographis paniculata extracts in Staphylococcus aureus-induced rabbit dermatitis model

Background and Aim:

Dermatitis is a soft-tissue infection caused by Staphylococcus aureus. The recurrence of inflammatory skin is linked to clinical manifestations. Anti-inflammatory cytokines, which are essential for tissue damage, are released by bacteria through skin tissues. Oxidative stress causes inflammatory cells to necrotize and reduces their antioxidant profile, resulting in toxic damage to surrounding tissues. Although studies on the antibacterial effects of Thunbergia laurifolia Lindl., Curcuma longa L., Garcinia mangostana L., and Andrographis paniculata (Burm.). Bacterial infection of S. aureus have been conducted, most of these studies have been in vitro and were not related to the rabbit model. In addition, anti-inflammatory and antioxidant studies need to be evaluated. Thus, this study aims to compare the antibacterial, anti-inflammatory, and antioxidant properties of four local herbs with a standard antibiotic in S. aureus-induced rabbit dermatitis model.

Materials and Methods:

The skin of New Zealand white rabbits were artificially wounded using a sterile blade and then infected with S. aureus. The rabbits were divided into seven groups, each with three rabbits (Total 21 rabbits): The first group was the no infection group (no infection and no treatment with scarification), the second group was the no treatment group (S. aureus infection of the wound but no treatment), and the other five treated groups were T. laurifolia, C. longa, G. mangostana, A. paniculata, and bacitracin cream, all of which involved wound infection and treatments. The treatment lasted for 7 days. The antibacterial, anti-inflammatory, and antioxidant properties after treatment were measured.

Results:

The efficacy of T. laurifolia, C. longa, G. mangostana, and A. paniculata was similar to that of an antioxidant and free radical scavenging property. The bacterial infection process gradually reduced the activities of antioxidant systems (i.e., enzymatic levels and gene expressions) and total glutathione. However, the activities of the antioxidant system were steadily increased when treated with herbal extracts. During bacterial invasion of the skin, the concentration of thiobarbituric acid reactive molecules, the level of lipid peroxidation, and the expression of anti-inflammatory cytokine genes were increased. All these were decreased when herbal extracts were used to treat the lesion.

Conclusion:

It can be concluded that T. laurifolia, C. longa, G. mangostana, and A. paniculate extract have antibacterial, anti-inflammatory, and antioxidant properties and are effective antibacterial agents. G. mangostana is the most effective herbal extract for antidermatitis and has the potential to be used as an alternative topical treatment.

Cancer and Autoimmune Diseases: A Tale of Two Immunological Opposites?

The present article compares, side-by-side, cancer and autoimmune diseases in terms of innate and adaptive immune cells involvement, MHC Class I and Class II expression, TGFβ effect, immune modulating drugs effect and the effect of reactive oxygen species. The change in the inflammatory immune reaction during the progress of cancer and the effect of this change on the comorbidity of autoimmune diseases and cancer are discussed. The similar inflammatory properties of autoimmune diseases and early cancer, and the contrasting inflammatory properties of autoimmune diseases and advanced cancer elucidate the increased incidence of many types of cancer in patients with pre-existing autoimmune diseases and the decreased cancer-specific mortality of these patients. Stage-dependent effects of reactive oxygen-species on tumor proliferation are an additional probable cause for these epidemiological observations. The relationship: {standardized incidence ratio (SIR)} > {cancer-specific hazard ratio (HR)} for cancer patients with a history of autoimmune diseases is substantiated and rationalized.

Oxidative Stress Promotes Instability of Regulatory T Cells in Antineutrophil Cytoplasmic Antibody-Associated Vasculitis

We investigated the characteristics of regulatory T cells (Tregs), focusing on the relationship between their stability and reactive oxygen species (ROS), in antineutrophil cytoplasmic antibody-associated vasculitis (AAV). Intracellular expressions of effector cytokines, forkhead box protein 3 (FoxP3), ROS, phosphorylated mammalian target of rapamycin (mTOR), and sirtuin 1 (SIRT1) in Tregs from peripheral blood mononuclear cells (PBMCs) of patients with AAV and healthy controls (HC) were analyzed. The alterations in and functional ability of Tregs were compared before and after resveratrol (RVL) treatment of PBMCs in patients with AAV. Significantly higher expressions of interferon (IFN)-γ, interleukin (IL)-17, IL-4, ROS, and phosphorylated mTOR (pho-mTOR) and lower expression of SIRT1 in CD4+CD25+FoxP3+ cells were found in patients with AAV than in the HC. FoxP3 expression in CD4+CD25+ cells and suppressive function of Tregs were significantly lower in patients with AAV than in the HC. Tregs after RVL treatment demonstrated significant decreases in IFN-γ, ROS, and pho-mTOR levels and increases in FoxP3, SIRT1 levels, and functional activity. Conversely, the direct activation of SIRT1 by SRT1720 resulted in decreased FoxP3 expression, with no reduction in ROS levels. The pho-mTOR levels were significantly higher in Tregs after activation by SRT1720 than in those after RVL treatment. This study suggested that imbalanced changes in Tregs could be attributed to mTOR activation, in which ROS overproduction was predominantly implicated. Therefore, ROS is a key mediator for promoting Tregs instability in AAV.

Reactive Oxygen Species in Anticancer Immunity: A Double-Edged Sword

Reactive oxygen species (ROS) are critical mediators in many physiological processes including innate and adaptive immunity, making the modulation of ROS level a powerful strategy to augment anticancer immunity. However, current evidences suggest the necessity of a deeper understanding of their multiple roles, which may vary with their concentration, location and the immune microenvironment they are in. Here, we have reviewed the reported effects of ROS on macrophage polarization, immune checkpoint blocking (ICB) therapy, T cell activation and expansion, as well as the induction of immunogenic cell death. A majority of reports are indicating detrimental effects of ROS, but it is unadvisable to simply scavenge them because of their pleiotropic effects in most occasions (except in T cell activation and expansion where ROS are generally undesirable). Therefore, clinical success will need a clearer illustration of their multi-faced functions, as well as more advanced technologies to tune ROS level with high spatiotemporal control and species-specificity. With such progresses, the efficacy of current immunotherapies will be greatly improved by combining with ROS-targeted therapies.

Mitochondrial Reactive Oxygen Species Are Essential for the Development of Psoriatic Inflammation

Psoriasis is a common immune-mediated, chronic, inflammatory skin disease that affects approximately 2-3% of the population worldwide. Although there is increasing evidence regarding the essential roles of the interleukin (IL)-23/IL-17 axis and dendritic cell (DC)-T cell crosstalk in the development of skin inflammation, the contributions of mitochondrial function to psoriasis are unclear. In a mouse model of imiquimod (IMQ)-induced psoriasiform skin inflammation, we found that hematopoietic cell-specific genetic deletion of p32/C1qbp, a regulator of mitochondrial protein synthesis and metabolism, protects mice from IMQ-induced psoriatic inflammation. Additionally, we demonstrate that p32/C1qbp is an important regulator of IMQ-induced DC activation, both in vivo and in vitro. We also found that p32/C1qbp-deficient DCs exhibited impaired production of IL-1β, IL-23, and mitochondrial reactive oxygen species (mtROS) after IMQ stimulation. Because the inhibition of mtROS suppressed IMQ-induced DC activation and psoriatic inflammation, we presume that p32/C1qbp and mtROS can serve as therapeutic targets in psoriasis.

Galangin ameliorates Imiquimod-Induced psoriasis-like skin inflammation in BALB/c mice via down regulating NF-κB and activation of Nrf2 signaling pathways

Psoriasis is a most common chronic autoimmune-arbitrated cutaneous inflammatory skin disorder by unclear pathogenesis. In this current study we demonstrated the effect of galangin (GAL) on imiquimod (IMQ)-induced psoriasis-like skin inflammation and decipher its possible protective mechanism which has not been investigated. The in vivo results revealed that GAL at 1% w/w and 2% w/w for six consecutive days markedly reduced IMQ-induced PASI scoring, skin, ear thickness, hematological markers, levels of nitrites, TBARS, MPO, histopathological, as well modulated the protein levels of pro-inflammatory mediators of COX-2, iNOS, NF-κB pathway and pro-inflammatory cytokines IL-17, IL-23, IL-1β in the skin and also IL-6, TNF-α in both skin and serum. Besides, GAL restored the levels of antioxidants markers such as SOD, CAT, GST, GSH, GR and Vit-C, anti-inflammatory cytokine of IL-10, and the protein levels of Nrf2/HO-1 in the skin compared to the IMQ group. Finally, our study demonstrates that GAL exerted its protective effect by up-regulating the anti-inflammatory and the antioxidant markers against psoriasis pre-clinical models indicating its potency for treating psoriasis in humans.

A Localized Aldara (5% Imiquimod)-Induced Psoriasiform Dermatitis Model in Mice Using Finn Chambers

The expanding number of research studies utilizing the imiquimod-induced psoriasiform dermatitis model attests to the usefulness of this procedure. Advantages of this model include rapid development of the skin response and cost-effectiveness. A major limitation is that application of imiquimod cream over large areas of skin, as well as licking and ingestion of the cream, may lead to severe systemic inflammation, which can cause a general decline in health, splenomegaly, and death. In this protocol, Finn chambers are used to localize the imiquimod cream to a small area of the skin. This results in production of severe and reproducible psoriatic skin reactions with significantly less imiquimod, greatly reducing the possibility of untoward systemic effects. Moreover, having psoriasiform and control skin areas on the same mice decreases inter-animal differences. The protocol can be readily adapted for other skin disease models involving topical application of test agents. This article also details functional measurements performed during assays, including skin thickness, blood perfusion, semiquantitative histopathological evaluation, determination of scaling score to monitor psoriatic symptoms, and collection of spleen and body weight data to identify systemic effects. © 2020 The Authors. Basic Protocol: Use of Finn chambers to induce psoriasiform skin reactions with imiquimod Support Protocol 1: Measurement of double-fold dorsal skin thickness Support Protocol 2: Measurement of blood perfusion Support Protocol 3: Determination of scaling score Support Protocol 4: Semiquantitative histopathological scoring Support Protocol 5: Assessment of systemic side effects in response to imiquimod application.

ROS and TGFβ: from pancreatic tumour growth to metastasis

Transforming growth factor β (TGFβ) signalling pathway switches between anti-tumorigenic function at early stages of cancer formation and pro-tumorigenic effects at later stages promoting cancer metastasis. A similar contrasting role has been uncovered for reactive oxygen species (ROS) in pancreatic tumorigenesis. Down-regulation of ROS favours premalignant tumour development, while increasing ROS level in pancreatic ductal adenocarcinoma (PDAC) enhances metastasis. Given the functional resemblance, we propose that ROS-mediated processes converge with the spatial and temporal activation of TGFβ signalling and thereby differentially impact early tumour growth versus metastatic dissemination. TGFβ signalling and ROS could extensively orchestrate cellular processes and this concerted function can be utilized by cancer cells to facilitate their malignancy. In this article, we revisit the interplay of canonical and non-canonical TGFβ signalling with ROS throughout pancreatic tumorigenesis and metastasis. We also discuss recent insight that helps to understand their conflicting effects on different stages of tumour development. These considerations open new strategies in cancer therapeutics.

Selenium nanoparticles produce a beneficial effect in psoriasis by reducing epidermal hyperproliferation and inflammation

Background

Psoriasis is a chronic autoimmune skin disease characterized by hyperproliferation of keratinocytes. Wide treatment options used to treat psoriasis is associated with various adverse effects. To overcome this nanoformulation is prepared. Selenium is an essential trace element and plays major role in oxidation reduction system. Toxicity and stability limits the applications of selenium. Toxicity can be reduced and stabilized upon preparation into nanoparticles.

Results

Selenium nanoparticles (SeNPs) exhibit potent apoptosis through the generation of reactive oxygen species (ROS) with cell cycle arrest. SeNPs topical gel application produced significant attenuation of psoriatic severity with the abrogation of acanthosis and splenomegaly. SeNPs reduced the phosphorylation and expressions of MAPKs, STAT3, GSK-3β, Akt along with PCNA, Ki67, and cyclin-D1.

Conclusion

SeNPs inhibit various inflammation and proliferation mediated pathways and could be an ideal candidate for psoriasis therapy.

Materials and methods

SeNPs were characterized and various techniques were used to determine apoptosis and other molecular mechanisms. In vivo studies were performed by inducing psoriasis with imiquimod (IMQ). SeNPs were administered via topical route.

Graphic Abstract

Reactive Oxygen Species in Autoimmune Cells: Function, Differentiation, and Metabolism

Accumulated reactive oxygen species (ROS) directly contribute to biomacromolecule damage and influence various inflammatory responses. Reactive oxygen species act as mediator between innate and adaptive immune cells, thereby influencing the antigen-presenting process that results in T cell activation. Evidence from patients with chronic granulomatous disease and mouse models support the function of ROS in preventing abnormal autoimmunity; for example, by supporting maintenance of macrophage efferocytosis and T helper 1/T helper 2 and T helper 17/ regulatory T cell balance. The failure of many anti-oxidation treatments indicates that ROS cannot be considered entirely harmful. Indeed, enhancement of ROS may sometimes be required. In a mouse model of rheumatoid arthritis (RA), absence of NOX2-derived ROS led to higher prevalence and more severe symptoms. In patients with RA, naïve CD4⁺ T cells exhibit inhibited glycolysis and enhanced pentose phosphate pathway (PPP) activity, leading to ROS exhaustion. In this "reductive" state, CD4⁺ T cell immune homeostasis is disrupted, triggering joint destruction, together with oxidative stress in the synovium.

Redox Regulation of Tolerogenic Dendritic Cells and Regulatory T Cells in the Pathogenesis and Therapy of Autoimmunity

Significance: Autoimmune diseases are progressively affecting westernized societies, as the proportion of individuals suffering from autoimmunity is steadily increasing over the past decades. Understanding the role of reactive oxygen species (ROS) in modulation of the immune response in the pathogenesis of autoimmune disorders is of utmost importance. The focus of this review is the regulation of ROS production within tolerogenic dendritic cells (tolDCs) and regulatory T (Treg) cells that have the essential role in the prevention of autoimmune diseases and significant potency in their therapy. Recent Advances: It is now clear that ROS are extremely important for the proper function of both DC and T cells. Antigen processing/presentation and the ability of DC to activate T cells depend upon the ROS availability. Treg differentiation, suppressive function, and stability are profoundly influenced by ROS presence. Critical Issues: Although a plethora of results on the relation between ROS and immune cells exist, it remains unclear whether ROS modulation is a productive way for skewing T cells and DCs toward a tolerogenic phenotype. Also, the possibility of ROS modulation for enhancement of regulatory properties of DC and Treg during their preparation for use in cellular therapy has to be clarified. Future Directions: Studies of DC and T cell redox regulation should allow for the improvement of the therapy of autoimmune diseases. This could be achieved through the direct therapeutic application of ROS modulators in autoimmunity, or indirectly through ROS-dependent enhancement of tolDC and Treg preparation for cell-based immunotherapy. Antioxid. Redox Signal. 34, 364-382.

Renin-Angiotensin System in the Tumor Microenvironment

For enhancing the antitumor effects of current immunotherapies including immune-checkpoint blockade, it is important to reverse cancer-induced immunosuppression. The renin-angiotensin system (RAS) controls systemic body fluid circulation; however, the presence of a local RAS in tumors has been reported. Furthermore, the local RAS in tumors influences various immune and interstitial cells and affects tumor immune response. RAS stimulation through the angiotensin II type 1 receptor has been reported to inhibit tumor immune response. Therefore, RAS inhibitors and combined treatment with immunotherapy are expected in the future. In this chapter, we provide a background on the RAS and describe the tumor environment with regard to the RAS and tumor immune response.

Imiquimod does not elicit inflammatory responses in the skin of the naked mole rat (Heterocephalus glaber)

Objective

Naked mole rat (Heterocephalus glaber) has recently attracted interest in biomedical research due to its exceptional longevity, cancer resistance and tolerance to potentially harmful conditions or stimuli. Given its unique attributes, this study was designed to characterize inflammatory skin reactions of this animal to topical application of imiquimod, a toll-like receptor 7 and 8 agonist that triggers psoriasis-like skin reaction.

Results

Imiquimod did not cause the expected psoriasis-like skin changes. There was no epidermal thickening and a straight epidermo-dermal boundary was maintained. There was no parakeratosis and the granular layer of epidermis was well formed. In the dermis, there was no leukocyte infiltration. This points to an exceptional nature of inflammatory/immune responses of this animal, but the mechanism could not be explained by our results. Naked mole rat could be a valuable negative model for studying psoriasis and other inflammatory skin conditions but as a prerequisite, there is need for further investigations to establish the mechanisms behind its lack of response to imiquimod.

Complex Tissue Regeneration in Mammals Is Associated With Reduced Inflammatory Cytokines and an Influx of T Cells

While mammals tend to repair injuries, other adult vertebrates like salamanders and fish regenerate damaged tissue. One prominent hypothesis offered to explain an inability to regenerate complex tissue in mammals is a bias during healing toward strong adaptive immunity and inflammatory responses. Here we directly test this hypothesis by characterizing part of the immune response during regeneration in spiny mice (Acomys cahirinus and Acomys percivali) vs. fibrotic repair in Mus musculus. By directly quantifying cytokines during tissue healing, we found that fibrotic repair was associated with a greater release of pro-inflammatory cytokines (i.e., IL-6, CCL2, and CXCL1) during acute inflammation in the wound microenvironment. However, reducing inflammation via COX-2 inhibition was not sufficient to reduce fibrosis or induce a regenerative response, suggesting that inflammatory strength does not control how an injury heals. Although regeneration was associated with lower concentrations of many inflammatory markers, we measured a comparatively larger influx of T cells into regenerating ear tissue and detected a local increase in the T cell associated cytokines IL-12 and IL-17 during the proliferative phase of regeneration. Taken together, our data demonstrate that a strong adaptive immune response is not antagonistic to regeneration and that other mechanisms likely explain the distribution of regenerative ability in vertebrates.

Cytotoxicity of Saikosaponin A targets HEKa cell through apoptosis induction by ROS accumulation and inflammation suppression via NF-κB pathway

Saikosaponin A (SSA) is a triterpenoid saponin extracted from oriental medicinal plant Radix bupleuri, possessing various biological functions such as anti-inflammatory, immune regulation and anti-virus. This study aimed to explore therapeutic effects of SSA on psoriasis in both vitro and vivo. Our results showed that SSA increased reactive oxygen species (ROS) generation, and decreased mitochondrial membrane potential (MMP) and M5-induced inflammatory cytokines levels in HEKa cells in a dose-dependent manner. In addition, SSA promoted apoptosis and suppressed phosphorylation of NF-κB in vitro, which were restored by the ROS scavenger N-acetylcysteine (NAC). In imiquimod (IMQ)-induced mice, gavage with SSA markedly decreased Psoriasis Area and Severity Index (PASI) score and ameliorated epidermal hyperplasia through inhibition of NF-κB and NLRP3 signaling pathway. In conclusion, our studies demonstrate that SSA induces apoptosis and suppresses inflammation in HEKa cells and ameliorates IMQ-induced psoriasis in mice, making it a therapeutic candidate for psoriasis.

The Influence of Reactive Oxygen Species in the Immune System and Pathogenesis of Multiple Sclerosis

Multiple roles have been indicated for reactive oxygen species (ROS) in the immune system in recent years. ROS have been extensively studied due to their ability to damage DNA and other subcellular structures. Noticeably, they have been identified as a pivotal second messenger for T-cell receptor signaling and T-cell activation and participate in antigen cross-presentation and chemotaxis. As an agent with direct toxic effects on cells, ROS lead to the initiation of the autoimmune response. Moreover, ROS levels are regulated by antioxidant systems, which include enzymatic and nonenzymatic antioxidants. Enzymatic antioxidants include superoxide dismutase, catalase, glutathione peroxidase, and glutathione reductase. Nonenzymatic antioxidants contain vitamins C, A, and E, glutathione, and thioredoxin. Particularly, cellular antioxidant systems have important functions in maintaining the redox system homeostasis. This review will discuss the significant roles of ROS generation and antioxidant systems under normal conditions, in the immune system, and pathogenesis of multiple sclerosis.

18β-Glycyrrhetinic acid induces human HaCaT keratinocytes apoptosis through ROS-mediated PI3K-Akt signaling pathway and ameliorates IMQ-induced psoriasis-like skin lesions in mice

Background

Psoriasis is a chronic inflammatory skin disease affecting 2–3% of the population worldwide. Hyperproliferative keratinocytes were thought to be an amplifier of inflammatory response, thereby sustaining persistence of psoriasis lesions. Agents with the ability to inhibit keratinocyte proliferation or induce apoptosis are potentially useful for psoriasis treatment. 18β-Glycyrrhetinic acid (GA), an active metabolite of glycyrrhizin, exhibits diverse pharmacological activities, including anti-inflammatory, anti-bacteria and anti-proliferation. The current study aims to evaluate the effects of GA on the proliferation and apoptosis of human HaCaT keratinocytes in vitro and investigate the effects of GA on the skin lesions of imiquimod (IMQ)-induced psoriasis-like mouse model in vivo.

Methods

Cell viability was assayed by CCK-8. Flow cytometry was performed to measure apoptosis and reactive oxygen species (ROS), with Annexin V-FITC/PI detection kit and DCFH-DA probe respectively. Caspase 9/3 activities were measured using caspase activity assay kits. The protein levels of Akt and p-Akt were determined using Western blotting. IMQ was applied to induce psoriasis-like skin lesions in mice. The histological change in mouse skin lesions was detected using hematoxylin and eosin (H&E) staining. The severity of skin lesions was scored based on Psoriasis Area Severity Index (PASI). RT-PCR was employed to examine the relative expression of TNF-α, IL-22 and IL-17A in mouse skin lesions.

Results

GA decreased HaCaT keratinocytes viability and induced cell apoptosis in a dose-dependent manner. In the presence of GA, intracellular ROS levels were significantly elevated. NAC, a ROS inhibitor, attenuated GA-mediated HaCaT keratinocytes growth inhibition and apoptosis. In addition, GA treatment remarkably decreased p-Akt protein level, which could be restored partially when cells were co-treated with GA and NAC. LY294002 (a PI3K inhibitor) treatment significantly enhanced GA-mediated cytotoxicity. Moreover, GA ameliorated IMQ-induced psoriasis-like skin lesions in mice.

Conclusions

GA inhibits proliferation and induces apoptosis in HaCaT keratinocytes through ROS-mediated inhibition of PI3K-Akt signaling pathway, and ameliorates IMQ-induced psoriasis-like skin lesions in mice.

Deficiency of glutathione peroxidase-1 and catalase attenuated diet-induced obesity and associated metabolic disorders

AIMS

Oxidative stress has been considered to contribute to the development of obesity-related metabolic disorders including insulin resistance. To the contrary, deficiency of an anti-oxidizing enzyme, glutathione peroxidase (GPx)-1, was reported to enhance insulin signaling, suggesting that oxidative stress may inhibit the development of type 2 diabetes. However, the beneficial effects of the absence of GPx-1 in metabolic homeostasis, including body weight control, have not yet been clearly manifested. To clarify the relationship between oxidative stress and obesity-related metabolic disorders, we investigated another mouse deficient with both GPx-1 and catalase (Cat).

METHODS

C57BL/6J wild-type and GPx-1^-/- × Cat^-/- mice were fed with a high-fat diet (60% fat) or a normal chow diet for 16 weeks and were investigated for metabolic and histological studies.

RESULTS

Body weight gain was significantly reduced, and glucose metabolism as well as hepatic steatosis was obviously improved in the GPx-1^-/- × Cat^-/- mice. The serum levels of insulin and total cholesterol were also significantly lowered. For the underlying mechanism, inflammation was attenuated and expression of markers for fat browning was enhanced in the visceral white adipose tissues.

CONCLUSIONS

Oxidative stress due to deficiency of GPx-1 and Cat may improve obesity-related metabolic disorders through attenuation of inflammation and fat browning.

Piperlongumine regulates epigenetic modulation and alleviates psoriasis-like skin inflammation via inhibition of hyperproliferation and inflammation

Psoriasis is an autoimmune skin disease, where chronic immune responses due to exaggerated cytokine signaling, abnormal differentiation, and evasion of keratinocytes apoptosis plays a crucial role in mediating abnormal keratinocytes hyperproliferation. From the therapeutic perspective, the molecules with strong anti-proliferative and anti-inflammatory properties could have tremendous relevance. In this study, we demonstrated that piperlongumine (PPL) treatment effectively abrogated the hyperproliferation and differentiation of keratinocytes by inducing ROS-mediated late apoptosis with loss of mitochondrial membrane potential. Besides, the arrest of cell cycle was found at Sub-G1 phase as a result of DNA fragmentation. Molecularly, inhibition of STAT3 and Akt signaling was observed with a decrease in proliferative markers such as PCNA, ki67, and Cyclin D1 along with anti-apoptotic Bcl-2 protein expression. Keratin 17 is a critical regulator of keratinocyte differentiation, and it was found to be downregulated with PPL significantly. Furthermore, prominent anti-inflammatory effects were observed by inhibition of lipopolysaccharide (LPS)/Imiquimod (IMQ)-induced p65 NF-κB signaling cascade and strongly inhibited the production of cytokine storm involved in psoriasis-like skin inflammation, thus led to the restoration of normal epidermal architecture with reduction of epidermal hyperplasia and splenomegaly. In addition, PPL epigenetically inhibited histone-modifying enzymes, which include histone deacetylases (HDACs) of class I (HDAC1-4) and class II (HDAC6) evaluated by immunoblotting and HDAC enzyme assay kit. In addition, our results show that PPL effectively inhibits the nuclear translocation of p65 and a histone modulator HDAC3, thus sequestered in the cytoplasm of macrophages. Furthermore, PPL effectively enhanced the protein-protein interactions of HDAC3 and p65 with IκBα, which was disrupted by LPS stimulation and were evaluated by Co-IP and molecular modeling. Collectively, our findings indicate that piperlongumine may serve as an anti-proliferative and anti-inflammatory agent and could serve as a potential therapeutic option in treating psoriasis.

Complex Tissue Regeneration in Mammals Is Associated With Reduced Inflammatory Cytokines and an Influx of T Cells

While mammals tend to repair injuries, other adult vertebrates like salamanders and fish regenerate damaged tissue. One prominent hypothesis offered to explain an inability to regenerate complex tissue in mammals is a bias during healing toward strong adaptive immunity and inflammatory responses. Here we directly test this hypothesis by characterizing part of the immune response during regeneration in spiny mice (Acomys cahirinus and Acomys percivali) vs. fibrotic repair in Mus musculus. By directly quantifying cytokines during tissue healing, we found that fibrotic repair was associated with a greater release of pro-inflammatory cytokines (i.e., IL-6, CCL2, and CXCL1) during acute inflammation in the wound microenvironment. However, reducing inflammation via COX-2 inhibition was not sufficient to reduce fibrosis or induce a regenerative response, suggesting that inflammatory strength does not control how an injury heals. Although regeneration was associated with lower concentrations of many inflammatory markers, we measured a comparatively larger influx of T cells into regenerating ear tissue and detected a local increase in the T cell associated cytokines IL-12 and IL-17 during the proliferative phase of regeneration. Taken together, our data demonstrate that a strong adaptive immune response is not antagonistic to regeneration and that other mechanisms likely explain the distribution of regenerative ability in vertebrates.

Repurposing an old drug for new use: Niclosamide in psoriasis-like skin inflammation

Drug discovery is an onerous, extremely expensive, and time-consuming process. Instead, drug repurposing is an attractive strategy for exploiting novel indications for a drug beyond its original use. The untapped potential of drug repurposing compensates the barriers associated with the drug discovery pipeline. Psoriasis is an autoimmune skin disease, where hyperproliferation of keratinocytes and exaggerated immune responses are the important hallmarks of the disease. Extensive in vitro and preclinical research has demonstrated that niclosamide was found to exert potent anticancer and anti-inflammatory properties by targeting STAT3, p65 NF-κB, and NFATc-1 signaling paradigm with minimal host toxicity. From the disease perspective, the static intracellular molecular network in both cancer and psoriasis share overlapping pathological features in terms of hyperproliferation and chronic inflammation, which is mediated by the aforementioned signaling cascade. The plausible mechanistic relevance has prompted us to investigate the implementation of niclosamide for repositioning in psoriasis. Our in vitro and in vivo findings suggest that niclosamide inhibits keratinocytes hyperproliferation by reactive oxygen species-mediated apoptosis through the loss of mitochondrial membrane potential, cell cycle arrest at Sub G1 phase, and DNA fragmentation. Furthermore, niclosamide treatment resulted in abrogation of lipopolysaccharide-induced inflammatory cytokine levels in murine macrophages. Additionally, our results provided a preclinical rationale in imiquimod (IMQ)-induced BALB/c mouse model, where niclosamide diligently mitigated the IMQ-induced epidermal hyperplasia and inflammation by downregulating STAT3, p65 NF-κB, and NFATc-1 transcription factors along with Akt, Ki-67, and ICAM-1 protein expression.

The systemic inflammatory response as a source of biomarkers and therapeutic targets in hepatocellular carcinoma

The pathogenesis of hepatocellular carcinoma (HCC) strongly relates to inflammation, with chronic up-regulation of pro-inflammatory mediators standing as a potential unifying mechanism that underscores the origin and progression of HCC independent of aetiology. Activation of the diverse pro-inflammatory mediators either within the tumour or its microenvironment is part of an active cross-talk between the progressive HCC and the host, which is known to influence clinical outcomes including recurrence after radical treatments and long-term survival. A number of clinical biomarkers to measure the severity of cancer-related inflammation are now available, most of which emerge from routine blood parameters including neutrophil, lymphocyte, platelet counts, as well as albuminaemia and C-reactive protein levels. In this review, we summarise the body of evidence supporting the biologic qualification of inflammation-based scores in HCC and review their potential in facilitating the prognostic assessment and treatment allocation in the individual patient. We also discuss the evidence to suggest modulation of tumour-promoting inflammation may act as a source of novel therapeutic strategies in liver cancer.

Fatty Acid Metabolites Combine with Reduced β Oxidation to Activate Th17 Inflammation in Human Type 2 Diabetes

Mechanisms that regulate metabolites and downstream energy generation are key determinants of T cell cytokine production, but the processes underlying the Th17 profile that predicts the metabolic status of people with obesity are untested. Th17 function requires fatty acid uptake, and our new data show that blockade of CPT1A inhibits Th17-associated cytokine production by cells from people with type 2 diabetes (T2D). A low CACT:CPT1A ratio in immune cells from T2D subjects indicates altered mitochondrial function and coincides with the preference of these cells to generate ATP through glycolysis rather than fatty acid oxidation. However, glycolysis was not critical for Th17 cytokines. Instead, β oxidation blockade or CACT knockdown in T cells from lean subjects to mimic characteristics of T2D causes cells to utilize ¹⁶C-fatty acylcarnitine to support Th17 cytokines. These data show long-chain acylcarnitine combines with compromised β oxidation to promote disease-predictive inflammation in human T2D.

Liquid crystalline nanoreservoir releasing a highly skin-penetrating berberine oleate complex for psoriasis management

Aim: The current work highlighted preparation of highly penetrating liquid crystalline nanoparticulates (LCNPs) reservoir of a solubility modified berberine oleate (Brb-OL) complex for effective psoriasis management. Materials & methods: Brb-OL-loaded LCNPs (Brb-OL-LCNPs) were prepared using hydrotrope method. Results: The proposed Brb-OL-LCNPs showed a particle size of 137 ± 3.7 nm and negative ζ-potential (-38 ± -5.85 mV). Brb-OL-LCNPs showed a threefold increase in the drug accumulated within rat skin and around tenfold increase in the drug permeation compared with crude Brb. In vivo studies revealed that topical application of Brb-OL-LCNPs hydrogel significantly alleviated psoriasis symptoms and reduced the levels of psoriatic inflammatory cytokines. Conclusion: Formulating Brb-OL in the LCNPs controlled the release, retention and permeation of the drug across skin layers, which are of prime importance for psoriasis management.

Methodological refinement of Aldara-induced psoriasiform dermatitis model in mice

Imiquimod (IMQ)-induced skin inflammation is currently the most widely accepted psoriasis animal model, however, it features several limitations. We have modified the IMQ-model to minimize its systemic effects towards effectively maintaining the characteristic skin reactions. The original protocol (OP) uses 62.5 mg Aldara cream (or vaseline) on the shaved back skin of mice for 4 days. In contrast, in our modified protocol (MP) 25 mg Aldara and vaseline are applied simultaneously in separate Finn chambers over the dorsal skin of mice. In both the OP and MP groups, histology showed unequivocal hallmarks of psoriasiform dermatitis. Additionally, skin scaling and blood perfusion values were similar. While Aldara elicited significantly increased skin thickness in the MP group, significant weight loss, spleen enlargement, increased inflammatory cytokine levels in plasma, and treatment related death were only observed in the OP group. Our new method reproduces psoriatic skin alterations highlighting considerably reduced systemic inflammatory reactions. Possessing psoriasiform and control skin areas on the same mouse also reduces inter-individual differences. Additionally, the new method permits prolonged IMQ treatment studies to mimic the chronic nature of psoriasis. Finally, our experimental approach may also be used in other mouse models, to prevent the undesired systemic effects of topically applied drugs.

Cold atmospheric plasma ameliorates imiquimod-induced psoriasiform dermatitis in mice by mediating antiproliferative effects

Psoriasis is a chronic hyperproliferative skin disease characterised by excessive growth of keratinocytes. Indeed, inducing keratinocyte apoptosis is a key mechanism responsible for psoriatic plaques clearance following some important existing therapies, which display pro-oxidant activity. Cold atmospheric plasma (CAP), acting as a tuneable source of reactive oxygen and nitrogen species (RONS), can controllably transfer RONS to the cellular environment, deliver antiproliferative RONS concentrations and exert antiproliferative and proapoptotic effects. This study was undertaken to evaluate the therapeutic potential of CAP in psoriasis. We used cell models of psoriasis-like inflammation by adding lipopolysaccharide (LPS) or tumour necrosis factor alpha (TNF-α) to HaCaT keratinocytes. Indirect plasma, plasma-activated medium (PAM), was administered to HaCaT cells. Atmospheric pressure plasma jet (APPJ) was applied directly to imiquimod (IMQ)-induced psoriasiform dermatitis in mice. The results showed that PAM induced an increase in intracellular ROS and caused keratinocyte apoptosis. Moreover, cells under inflammation showed lesser viability and larger apoptosis rate. With repeated administration of APPJ, psoriasiform lesions showed ameliorated morphological manifestation and reduced epidermal proliferation. Overall, this study supports that CAP holds good potential in psoriasis treatment.

Redox imbalance and IL-17 responses in memory CD4+ T cells from patients with psoriasis

All stages of the inflammatory process involved in T cell-mediated chronic skin disorders like psoriasis are affected by redox imbalance. On the other hand, Th17 cells have a critical role in the pathogenesis of psoriasis. In this study, we evaluated redox status in memory CD4 + T cells and plasma of patients with psoriasis and its correlation with IL-17 response. To this end, memory T cells were isolated from 10 patients with psoriasis and 10 controls. Intracellular Glutathione (GSH), reactive oxygen species (ROS) and superoxide as well as IL-17 were measured using flow cytometry. Plasma total anti-oxidant capacity (TAC) was quantified by ferric reducing ability of plasma (FRAP) assay. The expression of catalase (CAT), superoxide dismutase 1(SOD1), superoxide dismutase 2 (SOD2), nuclear factor, erythroid 2 like 2 (NFE2L2) and cytochrome b-245 beta chain (CYBB) genes were analysed using real-time PCR. Our results showed an increased intracellular ROS production in memory CD4 + T cells of patients compared to controls, (P = 0.04). Furthermore, a significant decrease in expression of catalase gene was found in patients, (P = 0.02). However, no significant differences were observed for intracellular GSH, IL-17 and TAC levels between patients and controls. Also, no correlation was seen between the intracellular IL-17 level and intracellular ROS, GSH and catalase gene expression levels. Collectively, we found an increased ROS production in stimulated memory T cells of patients that could be due to reduced expression of catalase gene. However, it seems that these redox abnormalities have no relationship with IL-17 response in memory T cells.

Metformin Promotes HaCaT Cell Apoptosis through Generation of Reactive Oxygen Species via Raf-1-ERK1/2-Nrf2 Inactivation

Although metformin (MET) may be useful for the treatment of psoriasis, the mechanisms underlying its method of action have yet to be fully elucidated. Here, the relationship between MET function and reactive oxygen species (ROS) levels and the underlying mechanism were explored in human immortalized keratinocyte cell line (HaCaT). HaCaT cells were incubated with MET at 0, 10, 20, 40, and 60 mM for 24 h. The cell viability was evaluated by the CCK-8 assay. The cell apoptosis rate and intracellular ROS levels were examined using flow cytometry. The protein expression and the phosphorylation levels of nuclear factor erythroid-derived 2 related factor 2 (Nrf2), Raf-1, and ERK1/2 were assessed by Western blot. The specific ROS scavenger N-acetyl-cysteine (NAC) and the specific Nrf2 agonist Oltipraz (OPZ) were used to analyze the effect of MET. MET decreased HaCaT cell proliferation and induced HaCaT cell apoptosis in a dose-dependent manner. MET was found to elevate intracellular ROS levels in a dose-dependent manner, while pretreatment with NAC attenuated these effects. MET inhibits the protein expression and the phosphorylation levels of Nrf2. The combination of OPZ and MET can significantly increase the cell viability, decrease the rate of apoptosis, and attenuate the intracellular ROS levels relative to MET alone. MET inhibits the protein expression and the phosphorylation levels of Raf-1 and ERK1/2. MET was found to attenuate Raf-1-ERK1/2 signaling in HaCaT cells to suppress the expression and phosphorylation levels of Nrf2, which contributed to the intracellular generation of ROS and the pro-apoptotic effects of MET.

The proinflammatory effects of macrophage-derived NADPH oxidase function in autoimmune diabetes

Type 1 diabetes (T1D) is an autoimmune disease culminating in the destruction of insulin-producing pancreatic β-cells. While ultimately a T cell-mediated disease, macrophages play an indispensable role in disease initiation and progression. Infiltrating macrophages generate an inflammatory environment by releasing NADPH oxidase-derived superoxide and proinflammatory cytokines. The synthesis of reactive oxygen species (ROS) is acknowledged as putative factors contributing to autoimmunity and β-cell damage in T1D. In addition to direct lysis, free radicals collectively participate in β-cell destruction by providing a redox-dependent third signal necessary for islet-reactive CD4 and CD8 T cell maturation and by inducing oxidative post-translational modifications of β-cell epitopes to further exacerbate autoimmune responses. This review will provide an overview of macrophage function and a synergistic cross-talk with redox biology that contributes to autoimmune dysregulation in T1D.