Human IL-23R Cytokine-Binding Homology Region-Fc Fusion Protein Ameliorates Psoriasis via the Decrease of Systemic Th17 and ILC3 Cell Responses

Rejuvenating fecal microbiota transplant enhances peripheral nerve repair in aged mice by modulating endoneurial inflammation

Peripheral nerve injury (PNI) resulting from trauma or neuropathies can cause significant disability, and its prognosis deteriorates with age. Emerging evidence suggests that gut dysbiosis and reduced fecal short-chain fatty acids (SCFAs) contribute to an age-related systemic hyperinflammation (inflammaging), which hinders nerve recovery after injury. This study thus aimed to evaluate the pro-regenerative effects of a rejuvenating fecal microbiota transplant (FMT) in a preclinical PNI model using aged mice. Aged C57BL/6 mice underwent bilateral crush injuries to their sciatic nerves. Subsequently, they either received FMT from young donors at three and four days after the injury or retained their aged gut microbiota. We analyzed gut microbiome composition and SCFA concentrations in fecal samples. The integrity of the ileac mucosal barrier was assessed by immunofluorescence staining of Claudin-1. Flow cytometry was utilized to examine immune cells and cytokine production in the ileum, spleen, and sciatic nerve. Various assessments, including behavioural tests, electrophysiological studies, and morphometrical analyses, were conducted to evaluate peripheral nerve function and repair following injury. Rejuvenating FMT reversed age-related gut dysbiosis by increasing Actinobacteria, especially Bifidobacteriales genera. This intervention also led to an elevation of gut SCFA levels and mitigated age-related ileac mucosal leakiness in aged recipients. Additionally, it augmented the number of T-helper 2 (Th2) and regulatory T (Treg) cells in the ileum and spleen, with the majority being positive for anti-inflammatory interleukin-10 (IL-10). In sciatic nerves, rejuvenating FMT resulted in increased M2 macrophage counts and a higher IL-10 production by IL-10+TNF-α- M2 macrophage subsets. Ultimately, restoring a youthful gut microbiome in aged mice led to improved nerve repair and enhanced functional recovery after PNI. Considering that FMT is already a clinically available technique, exploring novel translational strategies targeting the gut microbiome to enhance nerve repair in the elderly seems promising and warrants further evaluation.

Cang-ai volatile oil ameliorates imiquimod-induced psoriatic skin lesions by suppressing the ILC3s

ETHNOPHARMACOLOGICAL RELEVANCE

Cang-ai volatile oil (CAVO) is an aromatic Chinese medicine with potent antibacterial and immune regulatory properties. While CAVO has been used to treat upper respiratory tract infections, depression, otomycosis, and bacterial infections in the skin, its effect on psoriasis is unknown.

AIM OF THE STUDY

This study explores the effect and mechanism of CAVO in psoriasis intervention.

MATERIAL AND METHODS

The effect of CAVO on the expression of IL-6 and IL-1β was assessed in TNF-α-induced HaCaT cells using enzyme-linked immunosorbent assay (ELISA). Mice were given imiquimod (IMQ) and administered orally with different CAVO doses (0.03 and 0.06 g/kg) for 5 days. The levels of inflammatory cytokines related to group-3 innate lymphoid cells (ILC3s) in the skin were assessed using hematoxylin and eosin (H&E) staining, ELISA, and western blotting (WB). The frequency of ILC3s in mice splenocytes and skin cells was evaluated using flow cytometry.

RESULTS

The results demonstrated that CAVO decreased the expression of IL-6 and IL-1β in TNF-α- induced HaCaT cells. CAVO significantly reduced the severity of psoriatic symptoms in IMQ-induced mice. The expression of inflammatory cytokines in the skin, such as IL-1β, IL-6, IL-8, IL-22, IL-23, and IL-17 A were decreased, whereas IL-10 levels were increased. The mRNA expressions of TNF-α, IL-23 A, IL-23 R, IL-22, IL-17 A, and RORγt were down-regulated in skin tissues. CAVO also decreased the levels of NF-κB, STAT3, and JAK2 proteins.

CONCLUSIONS

CAVO potentially inhibits ILC3s activation to relieve IMQ-induced psoriasis in mice. These effects might be attributed to inhibiting the activation of NF-κB, STAT3, and JAK2 signaling pathways.

Understanding Type 3 Innate Lymphoid Cells and Crosstalk with the Microbiota: A Skin Connection

Innate lymphoid cells (ILCs) are a diverse population of lymphocytes classified into natural killer (NK) cells, ILC1s, ILC2s, ILC3s, and ILCregs, broadly following the cytokine secretion and transcription factor profiles of classical T cell subsets. Nonetheless, the ILC lineage does not have rearranged antigen-specific receptors and possesses distinct characteristics. ILCs are found in barrier tissues such as the skin, lungs, and intestines, where they play a role between acquired immune cells and myeloid cells. Within the skin, ILCs are activated by the microbiota and, in turn, may influence the microbiome composition and modulate immune function through cytokine secretion or direct cellular interactions. In particular, ILC3s provide epithelial protection against extracellular bacteria. However, the mechanism by which these cells modulate skin health and homeostasis in response to microbiome changes is unclear. To better understand how ILC3s function against microbiota perturbations in the skin, we propose a role for these cells in response to Cutibacterium acnes, a predominant commensal bacterium linked to the inflammatory skin condition, acne vulgaris. In this article, we review current evidence describing the role of ILC3s in the skin and suggest functional roles by drawing parallels with ILC3s from other organs. We emphasize the limited understanding and knowledge gaps of ILC3s in the skin and discuss the potential impact of ILC3-microbiota crosstalk in select skin diseases. Exploring the dialogue between the microbiota and ILC3s may lead to novel strategies to ameliorate skin immunity.

ILC3: a case of conflicted identity

Innate lymphoid cells type 3 (ILC3s) are the first line sentinels at the mucous tissues, where they contribute to the homeostatic immune response in a major way. Also, they have been increasingly appreciated as important modulators of chronic inflammatory and autoimmune responses, both locally and systemically. The proper identification of ILC3 is of utmost importance for meaningful studies on their role in immunity. Flow cytometry is the method of choice for the detection and characterization of ILC3. However, the analysis of ILC3-related papers shows inconsistency in ILC3 phenotypic definition, as different inclusion and exclusion markers are used for their identification. Here, we present these discrepancies in the phenotypic characterization of human and mouse ILC3s. We discuss the pros and cons of using various markers for ILC3 identification. Furthermore, we consider the possibilities for the efficient isolation and propagation of ILC3 from different organs and tissues for in-vitro and in-vivo studies. This paper calls upon uniformity in ILC3 definition, isolation, and propagation for the increased possibility of confluent interpretation of ILC3's role in immunity.

Comparative studies on mannan and imiquimod induced experimental plaque psoriasis inflammation in inbred mice

Psoriasis is a genetically determined, environmentally triggered, immune system-mediated autoimmune disease. Different animal models are needed to investigate the complex pathological mechanisms underlying this disease. Therefore, we established mannan-induced psoriasis model and compared with the most commonly used imiquimod-induced psoriasis in terms of disease, induction of innate immune cells, expression of cytokines, and the effect of dexamethasone treatment. Mannan significantly induced more severe psoriasis with better disease relapsing feature than imiquimod (IMQ). As determined by immunohistochemistry, IMQ induced significantly more infiltration of CD11c+ and F4/80+ cells than mannan in the skin. However, cytometric analysis showed a significant increase in the percentage of Gr-1+ neutrophils in the spleen and lymph nodes as well as F4/80+ macrophages in the spleen after mannan exposure. Variation in the percentage of significantly increased Vγ4 T cells was also found to be dependent on the lymphoid organs tested. However, there is a clear difference between these models in terms of expression of certain cytokine genes: IL-22, IL-23, IL-17E, and IL-17F were expressed more predominantly in mannan-induced inflammation, while IL-6 and IL-17A expressions were significantly higher in IMQ model. Interestingly, dexamethasone treatment strongly reduced epidermal thickness and histological scores induced by mannan than IMQ. Despite inducing psoriasis-like inflammation, certain differences and similarities were observed in the immune responses induced by mannan and IMQ. However, mannan-induced psoriasis model is relatively more simple, economical and less harmful to mice with an increased possibility to develop a chronic psoriasis model by exposing mice to mannan.

Anti-IL 23 biologics for the treatment of plaque psoriasis

INTRODUCTION

Psoriasis is a chronic inflammatory disease that can drastically affect a patient's quality-of-life and is associated with multiple comorbid conditions. The most common form of psoriasis is plaque psoriasis, commonly presenting as sharply demarcated, erythematous plaques with overlying silvery scale on the trunk, extensor surfaces, limbs, and scalp. Although initially limited to oral therapies, the choices in systemic therapies for moderate-to-severe plaque psoriasis have evolved with biologic immunotherapies being the main focus.

AREAS COVERED

In this review, we describe the IL-23/Th17 axis and IL-23 inhibitors as targets for a growing family of biologics. This family includes the FDA-approved medications ustekinumab, guselkumab, tildrakizumab, and risankizumab. We will review the safety and efficacy of these medications throughout various Phase 1,2, and 3, trials for moderate-to-severe psoriasis. A literature search of PubMed was utilized for the following terms: 'psoriasis and IL-23,' 'ustekinumab,' 'guselkumab,' 'tildrakizumab,' and 'risankizumab.' We also searched for clinical trials involving IL-23 inhibitors registered at ClinicalTrials.gov.

EXPERT OPINION

Anti-IL 23 therapy, especially anti-p19 monoclonal antibodies, should be considered first-line therapy for moderate-to-severe plaque psoriasis due to their efficacy and relative safety. More research is required to expand the scope of anti-p19 therapy to pediatric populations and additional indications such as psoriatic arthritis.

The regulatory mechanism and potential application of IL-23 in autoimmune diseases

IL-23 is a heterodimeric pro-inflammatory cytokine secreted by dendritic cells and macrophages that belongs to the IL-12 family. It has pro-inflammatory effects and is a key cytokine and upstream regulatory cytokine involved in protective immune responses, stimulating the differentiation and proliferation of downstream effectors such as Th17 cells. It is expressed in various autoimmune diseases such as psoriasis, systemic lupus erythematosus (SLE), rheumatoid arthritis (RA). The IL-23/TH17 axis formed by IL-23 and TH17 has been confirmed to participate in autoimmune diseases pathogenesis. IL-23R is the receptor for IL-23 and plays an activating role. Targeting IL-23 is currently the main strategy for the treatment of various autoimmune diseases. In this review we summarized the mechanism of action and clinical application potential of IL-23 in autoimmune diseases by summarizing the latest research results and reviewing the literature, which would help to further understand IL-23 and provide a theoretical basis for future clinical targeting and drug development.

Epidermal Hyperproliferation With Less Prominent Dermal Inflammation Is the Unique Histopathological Feature of the Refractory Lesions in Psoriasis Treated With Ustekinumab

ABSTRACT

Although ustekinumab (UST) shows excellent efficacy in treating psoriasis, not all patients have a complete clearance rate. The purpose of this study was to investigate the histopathological characteristics of refractory psoriasis lesions in patients with excellent response to UST. Fifty-seven patients with newly diagnosed psoriasis and 66 patients with a 75% reduction in the Psoriasis Area and Severity Index score after UST treatment were included. Computer-aided image analysis was performed to measure the epidermal thickness, horny layer thickness, number of dermal vessels, and dermal inflammatory cell infiltration rate. Parakeratosis was scored using a 4-point scale. These measurements were compared between the refractory lesions of UST-treated patients and the untreated lesions of newly diagnosed patients after the adjustment for confounding factors. The dermal inflammatory cell infiltration rate was significantly lower in the refractory lesions (P = 0.022). Meanwhile, the epidermal thickness, horny layer thickness, grade of parakeratosis, and dermal vessel count did not differ between the groups (P = 0.125, 0.719, 0.542, and 0.758, respectively). Subgroup analyses were performed within the UST-treated group after dividing them into 2 groups according to the number of treatments or treatment response rates. None of these features were significantly different between the subgroups. This study suggests that the reduction of dermal inflammation by UST was not sufficient to ameliorate the epidermal changes and implies the role of the interleukin-23-independent downstream cytokine pathway in causing the refractory lesions among patients who responded well to UST. The continuation of UST treatment might not further improve epidermal alterations.

Anti-IL-12/23 p40 antibody attenuates chronic graft-versus-host disease with lupus nephritis via inhibiting Tfh cell in mice

Systemic lupus erythematosus (SLE) is an autoimmune disease that is mainly caused by excessive accumulation of autoantibodies that target autoantibodies such as nucleic acids. T helper (Th) cell have been associated with the development of SLE. Typically, different subsets of Th cells secrete various cytokines to regulate the disease progression. IL-12 and IL-23 participate in the differentiation and activation of multiple Th cell subsets, including Th1, Th2, Th9, Th17, regulatory T (Treg) and follicular helper T (Tfh) cells. Because of the signature p40 subunit shared by IL-12 and IL-23, blocking IL-12/IL-23 signaling may interfere the differentiation of Th cell and directly inhibit the secretion of proinflammatory cytokines. In this study, we examined the effects of anti-IL-12/23 p40 antibody on chronic graft-versus-host disease with lupus nephritis, and found that the therapeutic effectiveness was mediated through the inhibition of Tfh cell in mice. Moreover, anti-IL-12/23 p40 antibody inhibited human Tfh cell differentiation in vitro. These results strongly suggest that Tfh cell contribute to the pathogenesis of SLE, and the neutralization of IL-12/IL-23 signaling during Tfh cell differentiation may be critical for the treatment of SLE.

Interleukin 23 and autoimmune diseases: current and possible future therapies

PURPOSE

IL-23 is a central proinflammatory cytokine with a wide range of influence over immune response. It is implicated in several autoimmune diseases due to the infinite inflammatory loops it can create through the positive feedbacks of both IL-17 and IL-22 arms. This made IL-23 a key target of autoimmune disorders therapy, which indeed was proven to inhibit inflammation and ameliorate diseases. Current autoimmune treatments targeting IL-23 are either by preventing IL-23 ligation to its receptor (IL-23R) via antibodies or inhibiting IL-23 signaling by signaling downstream mediators' inhibitors, with each approach having its own pros and cons.

METHODS

Literature review was done to further understand the biology of IL-23 and current therapies.

RESULTS

In this review, we discuss the biological features of IL-23 and its role in the pathogenesis of autoimmune diseases including psoriasis, rheumatoid arthritis and inflammatory bowel diseases. Advantages, limitations and side effects of each concept will be reviewed, suggesting several advanced IL-23-based bio-techniques to generate new and possible future therapies to overcome current treatments problems.

Treatment of psoriasis: janus kinases inhibitors and biologics for the interleukin-23/Th17 axis

With the discovery of the IL-23 / Th17 axis, the treatment of psoriasis has entered a new era. The aim of this study was to explore the progress of biologics and janus kinases (JAK) inhibitors targeting IL-23/Th17 axis in the treatment of psoriasis. review of English-language article was performed. Search terms included IL-17, IL-23, biologics, monoclonal antibodies, neutralizing antibodies, JAK, inhibitors, Psoriasis Area Severity Index and psoriasis. Data were selected from two phase 2 clinical trials; and nine phase 3 randomized, double-blind clinical trials; and other clinical trials. This review analyzes skin lesion clearance and major adverse reactions of 9 mAbs including mirikizumab and bimekizumab. At the same time, the research progress and prospects of three non-IgG small molecule biologics are analyzed too. This paper also compares the efficacy and limitations of biologics targeting the IL-23/Th17 axis with non-biologics acting on the JAK-signal transducer and activator of transcription pathway. The IL-17A/F inhibitors and non-IgG small molecule biologics that are being studied will bring a revolutionary development to the treatment of psoriasis. Topical application of JAK inhibitors can not only achieve the purpose of treating psoriasis, but also reduce the amounts of systemic medication, and reduces side effects. Each drug has its own indication, and the effect of the drug can be better achieved by selecting the indication for the drug.