Prevalence of fungal colonization among patients with psoriasis in difficult-to-treat areas: impact of apremilast on mycotic burden and clinical outcomes

Introduction

Fungi, including Candida, may be a trigger or exacerbate psoriasis, especially in difficult to treat (DTT) areas, through the activation of IL-17/23 axis.

Methods

In this study, seventy patients with DDT psoriasis were enrolled to evaluate Candida species and/or other opportunistic fungi colonization rate at baseline (T0) and the impact of apremilast on fungal load, clinical outcome, serum cytokine levels and biochemical serum profile of patients after 16, 24 and 52 weeks of treatment.

Results

In our population, 33 (47%) patients were colonized by Candida spp. at baseline. In 24 (34%) individuals Candida was detected in the oral cavity while in the remaining 9 (13%) individuals the fungus was isolated from stool samples. Twenty subjects were colonized by only the species C. albicans, whereas in the remaining 13 a combination of two or more species (C. albicans plus non-albicans strains) was found in the oral cavity. Moreover, 27 (39%) patients were affected by onychomycosis. At 52 weeks, apremilast treatment induced a full recovery from Candida colonization in 83% of patients colonized with a single species of Candida (C. albicans); while in those co-infected by two or more Candida spp. induced a significant reduction (colony counts >10 CFU/mL) in fungal load was observed in comparison to baseline. Among patients with onychomycosis, 78% (21/27) of them presented a complete clinical resolution of nail psoriasis and concomitant nail infections. Finally, improvements in clinical scores i.e., PASI, NAPSI, DLQI, itch VAS, PAIN VAS, scPGA and sPGA-G and biochemical serum profile, as well as a significant decrease in serum IL-17A, TGF-β 1 and IL-10 levels (from 8.51 to 4.16 pg/mL; from 66.10 to 48.70 ng/mL and from 20.05 to 14 pg/mL, respectively) were observed in all patients.

Conclusions

Fungi may play a role in the psoriasis pathogenesis. Apremilast has been shown to ameliorate psoriasis signs and symptoms and counteract fungal overgrowth, probably by dampening inflammation, triggered by the fungal infections themselves. Thus, apremilast may represent an effective therapeutic approach in the treatment of DTT psoriasis and modulate the fungal colonization.

Classical and Innovative Evidence for Therapeutic Strategies in Retinal Dysfunctions

The human retina is a complex anatomical structure that has no regenerative capacity. The pathogenesis of most retinopathies can be attributed to inflammation, with the activation of the inflammasome protein platform, and to the impact of oxidative stress on the regulation of apoptosis and autophagy/mitophagy in retinal cells. In recent years, new therapeutic approaches to treat retinopathies have been investigated. Experimental data suggest that the secretome of mesenchymal cells could reduce oxidative stress, autophagy, and the apoptosis of retinal cells, and in turn, the secretome of the latter could induce changes in mesenchymal cells. Other studies have evidenced that noncoding (nc)RNAs might be new targets for retinopathy treatment and novel disease biomarkers since a correlation has been found between ncRNA levels and retinopathies. A new field to explore is the interaction observed between the ocular and intestinal microbiota; indeed, recent findings have shown that the alteration of gut microbiota seems to be linked to ocular diseases, suggesting a gut-eye axis. To explore new therapeutical strategies for retinopathies, it is important to use proper models that can mimic the complexity of the retina. In this context, retinal organoids represent a good model for the study of the pathophysiology of the retina.

Skin Microbiota Profiles from Tape Stripping and Skin Biopsy Samples of Patients with Psoriasis Treated with Narrowband Ultraviolet B

Purpose

Although the pathogenesis of psoriasis involves the dermis, most previous studies collected samples using the swab technique. A recent study examining the microbiomes obtained via both skin biopsies and swabs revealed a significant difference in normal skin. We hypothesized that the microbiome profile of patients with psoriasis from tape stripping and skin biopsy might be different. This study sought to contribute to microbiome research on psoriasis by investigating the changes in the microbiome during narrowband ultraviolet B (NBUVB) therapy by comparing the results from the different sampling techniques of tape stripping and skin biopsy.

Patients and Methods

Twenty-three participants, including 14 patients with chronic plaque psoriasis and nine healthy controls, were recruited, and nine patients with psoriasis completed 20-sessions of NBUVB treatment. Skin microbiota from both techniques was analyzed using the 16S rRNA gene at baseline and after treatment.

Results

A clear difference was observed between the results from the two sampling techniques. Alpha diversity of the microbiota obtained from tape stripping was higher than that of the microbiota from skin biopsy, whereas beta diversity was clustered into two groups by sampling technique. The microbiome was altered during NBUVB treatment using both sampling techniques.

Conclusion

Different sampling techniques resulted in different microbiome profiles in patients with psoriasis. Tape stripping and swabs are feasible procedures and are mostly used in psoriasis and other skin microbiome studies; however, skin biopsy may also expand our understanding of psoriasis and other skin diseases that pathophysiology involves deeper to the dermis or subcutaneous tissue.

Skin and Gut Microbiome in Psoriasis: Gaining Insight Into the Pathophysiology of It and Finding Novel Therapeutic Strategies

Psoriasis affects the health of myriad populations around the world. The pathogenesis is multifactorial, and the exact driving factor remains unclear. This condition arises from the interaction between hyperproliferative keratinocytes and infiltrating immune cells, with poor prognosis and high recurrence. Better clinical treatments remain to be explored. There is much evidence that alterations in the skin and intestinal microbiome play an important role in the pathogenesis of psoriasis, and restoration of the microbiome is a promising preventive and therapeutic strategy for psoriasis. Herein, we have reviewed recent studies on the psoriasis-related microbiome in an attempt to confidently identify the “core” microbiome of psoriasis patients, understand the role of microbiome in the pathogenesis of psoriasis, and explore new therapeutic strategies for psoriasis through microbial intervention.

Lack of Effect of Murine Norovirus Infection on the CD4+ CD45RBhigh T-cell Adoptive Transfer Mouse Model of Inflammatory Bowel Disease

Murine norovirus (MNV) infection is highly prevalent in laboratory mice. Although MNV infection does not typically induce clinical disease in most laboratory mice, infection may nonetheless affect mouse models of disease by altering immune responses. We previously reported that MNV altered the bacterial-induced mouse model of inflammatory bowel disease (IBD) using Helicobacter-infected Mdr1a-/- mice. Therefore, we hypothesized that MNV infection would exacerbate another mouse model of IBD, the T-cell adoptive transfer (AT) model. In this model, Helicobacter infection is used to accelerate the progression of IBD induced by AT of naïve CD4+CD45RBhigh T cells into B6.129S7- Rag1tm1Mom/J (Rag1-/-) mice. We evaluated the effects of MNV infection in both Helicobacter-accelerated as well as Helicobacter-free AT models. In our studies, Helicobacter-infected Rag1-/- mice that received CD4+CD45RBhigh T cells through AT rapidly developed weight loss and typhlocolitis; MNV infection had no effect on disease severity or rate of progression. In the absence of Helicobacter infection, progression of IBD caused by AT of CD4+CD45RBhigh T cells was slower and typhlocolitis was less severe; this inflammation likewise was unaltered by MNV infection. These results indicate that MNV infection does not alter IBD progression and severity in the CD4+CD45RBhigh T-cell AT model in Rag1-/- mice.

The Akkermansia muciniphila is a gut microbiota signature in psoriasis

Psoriasis is an immune-mediated chronic inflammatory skin disease. Although its pathogenesis is not fully understood, Th17 cells and the cytokines they produce, such as IL-17, IL-22 and IL-23, play critical roles in the pathogenesis of psoriasis. Evidence has demonstrated that psoriasis has some common features, including immune responses (due to Th17 cells) and inflammatory cytokine profiles, with systematic diseases including inflammatory bowel diseases (IBDs) and obesity. Recently, studies have demonstrated that the gut microbiota plays a crucial role in host homoeostasis and immune response, particular in Th17 cells, but the role of the gut microbiota in psoriasis remains unclear. To study the relationship between gut microbiota and psoriasis, we analysed microbiota profiles in psoriasis using a 16S rDNA sequencing platform, and we found that the abundance of Akkermansia muciniphila was significantly reduced in patients with psoriasis. A. muciniphila is believed to have an important function in the pathogenesis of IBD and obesity; therefore, A. muciniphila, which is an indicator of health status, may be a key node for psoriasis as well as IBD and obesity. Taken together, our study identified that gut microbiota signature and function are significantly altered in the gut of patients with psoriasis, which provides a novel angle to understanding the pathogenesis of psoriasis.

Gilz-Activin A as a Novel Signaling Axis Orchestrating Mesenchymal Stem Cell and Th17 Cell Interplay

Mesenchymal stem cells (MSC) are highly immunosuppressive cells able to reduce chronic inflammation through the active release of mediators. Recently, we showed that glucocorticoid-induced leucine zipper (Gilz) expression by MSC is involved in their therapeutic effect by promoting the generation of regulatory T cells. However, the mechanisms underlying this pivotal role of Gilz remain elusive.

Methods and Results In this study, we have uncovered evidence that Gilz modulates the phenotype and function of Th1 and Th17 cells likely by upregulating the level of Activin A and NO₂ secreted by MSC. Adoptive transfer experiments sustained this Gilz-dependent suppressive effect of MSC on Th1 and Th17 cell functions. In immunoregulatory MSC, obtained by priming with IFN-γ and TNF-α, Gilz was translocated to the nucleus and bound to the promoters of inos and Activin βA to induce their expression. The increased expression of Activin A directly impacted on Th17 cells fate by repressing their differentiation program through the activation of Smad3/2 and enhancing IL-10 production.

Conclusion Our results reveal how Gilz controls inos and Activin βA gene expression to ultimately assign immunoregulatory status to MSC able to repress the pathogenic Th17 cell differentiation program and uncover Activin A as a novel mediator of MSC in this process.

Innate-like function of memory Th17 cells for enhancing endotoxin-induced acute lung inflammation through IL-22

Lipopolysaccharide (LPS)-induced acute lung injury (ALI) is known as a mouse model of acute respiratory distress syndrome; however, the function of T-cell-derived cytokines in ALI has not yet been established. We found that LPS challenge in one lung resulted in a rapid induction of innate-type pro-inflammatory cytokines such as IL-6 and TNF-α, followed by the expression of T-cell-type cytokines, including IL-17, IL-22 and IFN-γ. We discovered that IL-23 is important for ALI, since blockage of IL-23 by gene disruption or anti-IL-12/23p40 antibody treatment reduced neutrophil infiltration and inflammatory cytokine secretion into the bronchoalveolar lavage fluid (BALF). IL-23 was mostly produced from F4/80(+)CD11c(+) alveolar macrophages, and IL-23 expression was markedly reduced by the pre-treatment of mice with antibiotics, suggesting that the development of IL-23-producing macrophages required commensal bacteria. Unexpectedly, among T-cell-derived cytokines, IL-22 rather than IL-17 or IFN-γ played a major role in LPS-induced ALI. IL-22 protein levels were higher than IL-17 in the BALF after LPS instillation, and the major source of IL-22 was memory Th17 cells. Lung memory CD4(+) T cells had a potential to produce IL-22 at higher levels than IL-17 in response to IL-1β plus IL-23 without TCR stimulation. Our study revealed an innate-like function of the lung memory Th17 cells that produce IL-22 in response to IL-23 and are involved in exaggeration of ALI.

Low-Dose Intestinal Trichuris muris Infection Alters the Lung Immune Microenvironment and Can Suppress Allergic Airway Inflammation

Immunological cross talk between mucosal tissues such as the intestine and the lung is poorly defined during homeostasis and disease. Here, we show that a low-dose infection with the intestinally restricted helminth parasite Trichuris muris results in the production of Th1 cell-dependent gamma interferon (IFN-γ) and myeloid cell-derived interleukin-10 (IL-10) in the lung without causing overt airway pathology. This cross-mucosal immune response in the lung inhibits the development of papain-induced allergic airway inflammation, an innate cell-mediated type 2 airway inflammatory disease. Thus, we identify convergent and nonredundant roles of adaptive and innate immunity in mediating cross-mucosal suppression of type 2 airway inflammation during low-dose helminth-induced intestinal inflammation. These results provide further insight in identifying novel intersecting immune pathways elicited by gut-to-lung mucosal cross talk.

Immunopathological characterization of selected mouse models of inflammatory bowel disease: Comparison to human disease

Inflammatory bowel diseases (IBD) are chronic, relapsing conditions of multifactorial etiology. The two primary diseases of IBD are Crohn's disease (CD) and ulcerative colitis (UC). Both entities are hypothesized to occur in genetically susceptible individuals due to microbial alterations and environmental contributions. The exact etiopathogenesis, however, is not known for either disease. A variety of mouse models of CD and UC have been developed to investigate the pathogenesis of these diseases and evaluate treatment modalities. Broadly speaking, the mouse models can be divided into 4 categories: genetically engineered, immune manipulated, spontaneous and erosive/chemically induced. No one mouse model completely recapitulates the immunopathology of CD or UC, however each model possesses particular similarities to human IBD and offers advantageous for specific details of IBD pathogenesis. Here we discuss the more commonly used models in each category and critically evaluate how the immunopathology induced compares to CD or UC, as well as the advantages and disadvantages associated with each model.

IL-7 promotes long-term in vitro survival of unique long-lived memory subset generated from mucosal effector memory CD4+ T cells in chronic colitis mice

Colitogenic memory CD4(+) T cells are important in the pathogenesis of inflammatory bowel disease (IBD). Although memory stem cells with high survival and self-renewal capacity were recently identified in both mice and humans, it is unclear whether a similar subset is present in chronic colitis mice. We sought to identify and purify a long-lived subset of colitogenic memory CD4(+) T cells, which may be targets for treatment of IBD. A long-lived subset of colitogenic memory CD4(+) T cells was purified using a long-term culture system. The characteristics of these cells were assessed. Interleukin (IL)-7 promoted the in vitro survival for >8 weeks of lamina propria (LP) CD4(+) T cells from colitic SCID mice previously injected with CD4(+)CD45RB(high) T cells. These cells were in a quiescent state and divided a maximum of 5 times in 4 weeks. LP CD4(+) T cells expressed higher levels of Bcl-2, integrin-α4β7, CXCR3 and CD25 after than before culture, as well as secreting high concentrations of IL-2 and low concentrations of IFN-γ and IL-17 in response to intestinal bacterial antigens. LP CD4(+) T cells from colitic mice cultured with IL-7 for 8 weeks induced more severe colitis than LP CD4(+) T cells cultured for 4 weeks. We developed a novel culture system to purify a long-lived, highly pathogenic memory subset from activated LP CD4(+) T cells. IL-7 promoted long-term in vitro survival of this subset in a quiescent state. This subset will be a novel, effective target for the treatment of IBD.