IL-22 and TNF-α represent a key cytokine combination for epidermal integrity during infection with Candida albicans

Breaking Barriers: Candidalysin Disrupts Epithelial Integrity and Induces Inflammation in a Gut-on-Chip Model

Candida albicans is an opportunistic pathogenic yeast commonly found in the gastrointestinal tract of healthy humans. Under certain conditions, it can become invasive and cause life-threatening systemic infections. One mechanism used by C.albicans to breach the epithelial barrier is the secretion of candidalysin, a cytolytic peptide toxin. Candidalysin damages epithelial membranes and activates the innate immune response, making it key to C.albicans' pathogenicity and a promising therapeutic target. Although candidalysin mediates C. albicans translocation through intestinal layers, its impact on epithelial responses is not fully understood. This study aims to characterize this response and develop scalable, quantitative methodologies to assess candidalysin's toxicological effects using gut-on-chip models. We used the OrganoPlate® platform to expose Caco-2 tubules to candidalysin and evaluated their response with trans-epithelial electrical resistance (TEER), protein detection, and immunostaining. We then validated our findings in a proof-of-concept experiment using human intestinal organoid tubules. Candidalysin impaired barrier integrity, induced actin remodeling, and increased cell permeability. It also induced the release of LDH, cytokines, and the antimicrobial peptide LL37, suggesting cellular damage, inflammation, and antimicrobial activity. This study strengthens our understanding of candidalysin's role in C. albicans pathogenesis and suggests new therapeutic strategies targeting this toxin. Moreover, patient-derived organoids show promise for capturing patient heterogeneity and developing personalized treatments.

Beyond the dichotomy: understanding the overlap between atopic dermatitis and psoriasis

Atopic dermatitis and psoriasis have traditionally been considered distinct inflammatory skin diseases with unique pathogenic mechanisms. However, accumulating evidence suggests significant overlap in their immunological pathways, metabolic features, and microbiome characteristics, challenging this conventional dichotomy. This review comprehensively examines the complex relationship between psoriasis and atopic dermatitis, with particular emphasis on their shared and distinct pathogenic mechanisms. We analyze the immunological networks, metabolic pathways, and microbial factors contributing to their development and progression. The review expands upon the disease spectrum hypothesis and discusses the nomenclature for conditions exhibiting features of both diseases. We critically evaluate the clinical and histopathological characteristics of concomitant psoriasis and atopic dermatitis, highlighting recent advances in molecular diagnostics for accurate disease differentiation. Importantly, we propose standardized diagnostic criteria for psoriasis dermatitis and examine current therapeutic strategies for managing overlapping conditions. Recent developments in targeted therapies and their implications for treatment selection are thoroughly discussed. By synthesizing current evidence and identifying knowledge gaps, this review provides insights into the complex interplay between psoriasis and atopic dermatitis, aiming to guide clinical decision-making and future research directions in this evolving field.

The role of IL-22 in cancer

Interleukin-22, discovered in the year of 2000, is a pleiotropic Th17 cytokine from the IL-10 family of cytokines. IL-22 signals through the type 2 cytokine receptor complex IL-22R and predominantly activates STAT3. This pathway leads to the transcription of several different types of genes, giving IL-22 context-specific functions ranging from inducing antimicrobial peptide expression to target cell proliferation. In recent years, it has been shown that IL-22 is involved in the pathogenesis of neoplasia in some cancers through its pro-proliferative and anti-apoptotic effects. This review highlights studies with recent discoveries and conclusions drawn on IL-22 and its involvement and function in various cancers. Such a study may be helpful to better understand the role of IL-22 in cancer so that new treatment could be developed targeting IL-22.

Topical application of activator protein-1 inhibitor T-5224 suppresses inflammation and improves skin barrier function in a murine atopic dermatitis-like dermatitis

BACKGROUND

Selective activator protein (AP)-1 inhibitors are potentially promising therapeutic agents for atopic dermatitis (AD) because AP-1 is an important regulator of skin inflammation. However, few studies have investigated the effect of topical application of AP-1 inhibitors in treating inflammatory skin disorders.

METHODS

Immunohistochemistry was conducted to detect phosphorylated AP-1/c-Jun expression of skin lesions in AD patients. In the in vivo study, 1 % T-5224 ointment was topically applied for 8 days to the ears of 2,4 dinitrofluorobenzene challenged AD-like dermatitis model mice. Baricitinib, a conventional therapeutic agent Janus kinase (JAK) inhibitor, was also topically applied. In the in vitro study, human epidermal keratinocytes were treated with T-5224 and stimulated with AD-related cytokines.

RESULTS

AP-1/c-Jun was phosphorylated at skin lesions in AD patients. In vivo, topical T-5224 application inhibited ear swelling (P < 0.001), restored filaggrin (Flg) expression (P < 0.01), and generally suppressed immune-related pathways. T-5224 significantly suppressed Il17a and l17f expression, whereas baricitinib did not. Baricitinib suppressed Il4, Il19, Il33 and Ifnb expression, whereas T-5224 did not. Il1a, Il1b, Il23a, Ifna, S100a8, and S100a9 expression was cooperatively downregulated following the combined use of T-5224 and baricitinib. In vitro, T-5224 restored the expression of FLG and loricrin (LOR) (P < 0.05) and suppressed IL33 expression (P < 0.05) without affecting cell viability and cytotoxicity.

CONCLUSIONS

Topical T-5224 ameliorates clinical manifestations of AD-like dermatitis in mice. The effect of this inhibitor is amplified via combined use with JAK inhibitors.

Skin innate immune response against fungal infections and the potential role of trained immunity

Fungal skin infections are distributed worldwide and can be associated with economic and social traits. The immune response related to skin cells is complex and its understanding is essential to the comprehension of each cell's role and the discovery of treatment alternatives. The first studies of trained immunity (TI) described the ability of monocytes, macrophages and natural killer (NK) cells to develop a memory-like response. However, the duration of TI does not reflect the shorter lifespan of these cells. These conclusions supported later studies showing that TI can be observed in stem and haematopoietic cells and, more recently, also in non-immune skin cells such as fibroblasts, highlighting the importance of resident cells in response to skin disorders. Besides, the participation of less studied proinflammatory cytokines in the skin immune response, such as IL-36γ, shed light into a new possibility of inflammatory pathway blockade by drugs. In this review, we will discuss the skin immune response associated with fungal infections, the role of TI in skin and clinical evidence supporting opportunities and challenges of TI and other inflammatory responses in the pathogenesis of fungal skin infections.

Immunolocalization of antibacterial peptide S100A7 in mastitis goat mammary gland and lipopolysaccharide induces the expression and secretion of S100A7 in goat mammary gland epithelial cells via TLR4/NFκB signal pathway

The antimicrobial peptide S100A7, with antimicrobial activities for a broad spectrum of bacteria, has attracted more and more attention for the prevention and treatment of mastitis. However, there is little information about the expression and regulation mechanism of S100A7 in mastitis goats. This study revealed that S100A7 was mainly expressed in the stratified squamous epithelium of teat skin and streak canal, and S100A7 was present weakly in the healthy goat alveolus yet densely in the mastitis goat collapsed alveolus. Goat mammary epithelial cells (MECs) were isolated and treated with 2.5, 5, 10 and 20 µg/mL lipopolysaccharide (LPS) respectively for a different time, S100A7 mRNA expression and protein secretion were upregulated significantly with LPS treatment for 3 h, and the secretion level of S100A7 descended after 48 h treatment for all of these four groups. Moreover, after treatment with LPS, the mRNA levels of Toll-like receptor 4 (TLR4) and MyD88 were up-regulated, and the phosphorylation of p65 was up-regulated markedly. However, adding TLR4 inhibitor TAK-242 or/and NF-κB inhibitor QNZ significantly suppressed the phosphorylation of p65, and then inhibited the expression and secretion of S100A7 induced by LPS treatment. In conclusion, LPS induced the expression and secretion of S100A7 in goat MECs via TLR4/NF-κB signaling pathway.

Transcriptional Profiling of SARS-CoV-2-Infected Calu-3 Cells Reveals Immune-Related Signaling Pathways

The COVID-19 disease, caused by the Severe Acute Respiratory Syndrome Coronavirus 2 (SARS-CoV-2), emerged in late 2019 and rapidly spread worldwide, becoming a pandemic that infected millions of people and caused significant deaths. COVID-19 continues to be a major threat, and there is a need to deepen our understanding of the virus and its mechanisms of infection. To study the cellular responses to SARS-CoV-2 infection, we performed an RNA sequencing of infected vs. uninfected Calu-3 cells. Total RNA was extracted from infected (0.5 MOI) and control Calu-3 cells and converted to cDNA. Sequencing was performed, and the obtained reads were quality-analyzed and pre-processed. Differential expression was assessed with the EdgeR package, and functional enrichment was performed in EnrichR for Gene Ontology, KEGG pathways, and WikiPathways. A total of 1040 differentially expressed genes were found in infected vs. uninfected Calu-3 cells, of which 695 were up-regulated and 345 were down-regulated. Functional enrichment analyses revealed the predominant up-regulation of genes related to innate immune response, response to virus, inflammation, cell proliferation, and apoptosis. These transcriptional changes following SARS-CoV-2 infection may reflect a cellular response to the infection and help to elucidate COVID-19 pathogenesis, in addition to revealing potential biomarkers and drug targets.

Advancing Vaccine Strategies against Candida Infections: Exploring New Frontiers

Candida albicans, along with several non-albicans Candida species, comprise a prominent fungal pathogen in humans, leading to candidiasis in various organs. The global impact of candidiasis in terms of disease burden, suffering, and fatalities is alarmingly high, making it a pressing global healthcare concern. Current treatment options rely on antifungal drugs such as azoles, polyenes, and echinocandins but are delimited due to the emergence of drug-resistant strains and associated adverse effects. The current review highlights the striking absence of a licensed antifungal vaccine for human use and the urgent need to shift our focus toward developing an anti-Candida vaccine. A number of factors affect the development of vaccines against fungal infections, including the host, intraspecies and interspecies antigenic variations, and hence, a lack of commercial interest. In addition, individuals with a high risk of fungal infection tend to be immunocompromised, so they are less likely to respond to inactivated or subunit whole organisms. Therefore, it is pertinent to discover newer and novel alternative strategies to develop safe and effective vaccines against fungal infections. This review article provides an overview of current vaccination strategies (live attenuated, whole-cell killed, subunit, conjugate, and oral vaccine), including their preclinical and clinical data on efficacy and safety. We also discuss the mechanisms of immune protection against candidiasis, including the role of innate and adaptive immunity and potential biomarkers of protection. Challenges, solutions, and future directions in vaccine development, namely, exploring novel adjuvants, harnessing the trained immunity, and utilizing immunoinformatics approaches for vaccine design and development, are also discussed. This review concludes with a summary of key findings, their implications for clinical practice and public health, and a call to action for continued investment in candidiasis vaccine research.

The mechanism of dendritic cell-T cell crosstalk in rheumatoid arthritis

Rheumatoid arthritis (RA) is a chronic inflammatory disease characterised by joint pain and swelling, synovial hyperplasia, cartilage damage, and bone destruction. The mechanisms of dendritic cell (DC) and T cell-mediated crosstalk have gradually become a focus of attention. DCs regulate the proliferation and differentiation of CD4+ T cell subtypes through different cytokines, surface molecules, and antigen presentation. DC-T cell crosstalk also blocks antigen presentation by DCs, ultimately maintaining immune tolerance. DC-T cell crosstalk mainly involves chemokines, surface molecules (TonEBP, NFATc1), the PD-L1/PD-1 signalling axis, and the TGF-β signalling axis. In addition, DC-T cell crosstalk in RA is affected by glycolysis, reactive oxygen species, vitamin D, and other factors. These factors lead to the formation of an extremely complex regulatory network involving various mechanisms. This article reviews the key immune targets of DC-T cell crosstalk and elucidates the mechanism of DC-T cell crosstalk in RA to provide a basis for the treatment of patients with RA.

Eczematized psoriasis - a frequent but often neglected variant of plaque psoriasis

Psoriasis is a common chronic inflammatory skin disease that causes systemic inflammation and severely impacts the patient's quality of life. Several highly effective therapeutics for psoriasis have been approved in recent years. However, in real life, a high proportion of patients either do not experience the clinical improvement observed in clinical trials or develop a secondary loss of efficacy. This may be a result of unrecognized endotypes of psoriasis that need to be characterized in greater depth to enable selection of an appropriate therapy. Eczematized psoriasis, which occurs in approximately 5-10% of patients with psoriasis, is an often-neglected variant of psoriasis. The term "eczematized psoriasis" refers to patients developing psoriasis with similarities to eczema. These patients typically present with severe itching, and skin biopsies often reveal eosinophil granulocytes, serum crusts, or spongiosis, which are frequently observed in eczema. From an immunological perspective, additional signaling pathways that are responsible for eczema reactions might be activated in eczematized psoriasis compared to classical plaque psoriasis. This review summarizes the key clinical, histological, and immunological features of eczematized psoriasis, proposes diagnostic criteria, and evaluates the therapeutic options for eczematized psoriasis.

They shall not grow mold: Soldiers of innate and adaptive immunity to fungi

Fungi are ubiquitous commensals, seasoned predators, and important agents of emerging infectious diseases [1 ]. The immune system assumes the essential responsibility for responding intelligently to the presence of known and novel fungi to maintain host health. In this Review, we describe the immune responses to pathogenic fungi and the varied array of fungal agents confronting the vertebrate host within the broader context of fungal and animal evolution. We provide an overview of the mechanistic details of innate and adaptive antifungal immune responses, as well as ways in which these basic mechanisms support the development of vaccines and immunotherapies.

Management of Infections in Psoriatic Patients Treated with Systemic Therapies: A Lesson from the Immunopathogenesis of Psoriasis

Modern treatments continue to be developed based on identifying targets within the innate and adaptive immune pathways associated with psoriasis. Whilst there is a sound biologic rationale for increased risk of infection following treatment with immunomodulators, the clinical evidence is confounded by these agents being used in patients affected with several comorbidities. In an era characterized by an ever greater and growing risk of infections, it is necessary to always be updated on this risk. In this mini-review, we will discuss recent updates in psoriasis immunopathogenesis as a rationale for systemic therapy, outline the risk of infections linked to the disease itself and systemic therapy as well, and provide an overview of the prevention and management of infections.

A Systematic Review of Keratinocyte Secretions: A Regenerative Perspective

Cell regenerative therapy is a modern solution for difficult-to-heal wounds. Keratinocytes, the most common cell type in the skin, are difficult to obtain without the creation of another wound. Stem cell differentiation towards keratinocytes is a challenging process, and it is difficult to reproduce in chemically defined media. Nevertheless, a co-culture of keratinocytes with stem cells usually achieves efficient differentiation. This systematic review aims to identify the secretions of normal human keratinocytes reported in the literature and correlate them with the differentiation process. An online search revealed 338 references, of which 100 met the selection criteria. A total of 80 different keratinocyte secretions were reported, which can be grouped mainly into cytokines, growth factors, and antimicrobial peptides. The growth-factor group mostly affects stem cell differentiation into keratinocytes, especially epidermal growth factor and members of the transforming growth factor family. Nevertheless, the reported secretions reflected the nature of the involved studies, as most of them focused on keratinocyte interaction with inflammation. This review highlights the secretory function of keratinocytes, as well as the need for intense investigation to characterize these secretions and evaluate their regenerative capacities.

Immunopathogenesis and distinct role of Th17 in Periodontitis: A review

BACKGROUND

Periodontitis is a multifactorial inflammatory disease mediated by the host immune response to dental plaque. Periodontitis is characterized by periodontal bone loss and loss of tooth support. Several studies have corroborated the infiltration of T lymphocytes in periodontitis and correlated the infiltration with chronic inflammation in a dysregulated T cell-mediated immune response. The complexity of the disease has prompted multiple studies aiming to understand T cell-mediated pathogenesis.

HIGHLIGHT

Recent findings have demonstrated the pivotal role of helper T cells in many autoimmune diseases, such as rheumatoid arthritis, which has been conventionally correlated with periodontal bone loss. In contrast, the roles of helper T subsets, Th1, Th2, and particularly Th17, have not been explored. Th17-mediated pathogenesis is a significant aspect of the progression and therapy of periodontitis.

CONCLUSION

In this review, we highlight the complex role of Th17 in the underlying pro-inflammatory cascades mediated by a repertoire of Th17-released molecules and their role in aggravated inflammation in periodontitis. We also summarize recent therapeutics targeting Th17 and related molecules, primarily to ameliorate inflammation and maintain periodontal care.

Identification of differentially expressed genes and signaling pathways with Candida infection by bioinformatics analysis

BACKGROUND

Opportunistic Candida species causes severe infections when the human immune system is weakened, leading to high mortality.

METHODS

In our study, bioinformatics analysis was used to study the high-throughput sequencing data of samples infected with four kinds of Candida species. And the hub genes were obtained by statistical analysis.

RESULTS

A total of 547, 422, 415 and 405 differentially expressed genes (DEGs) of Candida albicans, Candida glabrata, Candida parapsilosis and Candida tropicalis groups were obtained, respectively. A total of 216 DEGs were obtained after taking intersections of DEGs from the four groups. A protein-protein interaction (PPI) network was established using these 216 genes. The top 10 hub genes (FOSB, EGR1, JUNB, ATF3, EGR2, NR4A1, NR4A2, DUSP1, BTG2, and EGR3) were acquired through calculation by the cytoHubba plug-in in Cytoscape software. Validated by the sequencing data of peripheral blood, JUNB, ATF3 and EGR2 genes were  significant statistical significance.

CONCLUSIONS

In conclusion, our study demonstrated the potential pathogenic genes in Candida species and their underlying mechanisms by bioinformatic analysis methods. Further, after statistical validation, JUNB, ATF3 and EGR2 genes were attained, which may be used as potential biomarkers with Candida species infection.

LncRNA: A Potential Target for Host-Directed Therapy of Candida Infection

Despite various drugs work against Candida, candidiasis represents clinical management challenges worldwide due to the rising incidence and recurrence rate, as well as epidemics, of new drug-resistant pathogens. Recent insights into interactions between Candida and hosts contribute to exploring novel therapeutic strategies, termed host-directed therapies (HDTs). HDTs are viable adjuncts with good efficacy for the existing standard antifungal regimens. However, HDTs induce other response unintendedly, thus requiring molecular targets with highly specificity. Long noncoding RNAs (lncRNAs) with highly specific expression patterns could affect biological processes, including the immune response. Herein, this review will summarize recent advances of HDTs based on the Candida–host interaction. Especially, the findings and application strategies of lncRNAs related to the host response are emphasized. We propose it is feasible to target lncRNAs to modulate the host defense during Candida infection, which provides a new perspective in identifying options of HDTs for candidiasis.

High Endurance Elite Athletes Show Age-dependent Lower Levels of Circulating Complements Compared to Low/Moderate Endurance Elite Athletes

Introduction: Aerobic exercise activates the complement system in the peripheral blood. However, the effect of age and high intensity endurance training on the levels of circulating complements and sassociated inflammatory cytokines, oxidative stress markers and cellular aging remains unknown.

Methods: In this study, serum samples from 79 elite athletes who belong to high (n = 48) and low/moderate (n = 31) endurance sports and two age groups (below 30 years old, n = 53, and above 30 years old, n = 26) were profiled for 14 complements. Linear models were used to assess differences in complements levels between sport and age groups. Spearmann’s correlation was used to assess the relationship among detected complements and proinflammatory cytokines, oxidative stress markers and telomere lengths.

Results: High endurance elite athletes exhibited significantly lower levels of circulating C2, C3b/iC3b and adipsin complements than their age-matched low/moderate endurance counterparts. Levels of C2, adipsin and C3b/iC3b were positively correlated with most detected complements, the pro-inflammatory cytokines TNF-alpha and IL-22 and the anti-oxidant enzyme catalase. However, they were negatively correlated with telomere length only in younger elite athletes regardless of their sport groups. Furthermore, high endurance elite athletes showed significantly lower concentrations of C3b/iC3b, C4b, C5, C5a, C1q, C3, C4, factor H and properdin in younger athletes compared to their older counterparts.

Conclusion: Our novel data suggest that high endurance elite athletes exhibit age-independent lower levels of circulating C2, C3b/iC3b and adipsin, associated with lower inflammatory, oxidative stress and cellular aging, as well as lower levels of 10 other complements in younger athletes compared to older counterparts. Assessing the effect of various levels of endurance sports on complements-based immune response provides a better understanding of exercise physiology and pathophysiology of elite athletes.

Engineering living therapeutics with synthetic biology

The steadfast advance of the synthetic biology field has enabled scientists to use genetically engineered cells, instead of small molecules or biologics, as the basis for the development of novel therapeutics. Cells endowed with synthetic gene circuits can control the localization, timing and dosage of therapeutic activities in response to specific disease biomarkers and thus represent a powerful new weapon in the fight against disease. Here, we conceptualize how synthetic biology approaches can be applied to programme living cells with therapeutic functions and discuss the advantages that they offer over conventional therapies in terms of flexibility, specificity and predictability, as well as challenges for their development. We present notable advances in the creation of engineered cells that harbour synthetic gene circuits capable of biological sensing and computation of signals derived from intracellular or extracellular biomarkers. We categorize and describe these developments based on the cell scaffold (human or microbial) and the site at which the engineered cell exerts its therapeutic function within its human host. The design of cell-based therapeutics with synthetic biology is a rapidly growing strategy in medicine that holds great promise for the development of effective treatments for a wide variety of human diseases.

Th17 Cells in Periodontitis and Its Regulation by A20

Periodontitis is a prevalent chronic disease that results in loss of periodontal ligament and bone resorption. Triggered by pathogens and prolonged inflammation, periodontitis is modulated by the immune system, especially pro-inflammatory cells, such as T helper (Th) 17 cells. Originated from CD4⁺ Th cells, Th17 cells play a central role for they drive and regulate periodontal inflammation. Cytokines secreted by Th17 cells are also major players in the pathogenesis of periodontitis. Given the importance of Th17 cells, modulators of Th17 cells are of great clinical potential and worth of discussion. This review aims to provide an overview of the current understanding of the effect of Th17 cells on periodontitis, as well as a brief discussion of current and potential therapies targeting Th17 cells. Lastly, we highlight this article by summarizing the causal relationship between A20 (encoded by TNFAIP3), an anti-inflammatory molecule, and Th17 cell differentiation.

Melanin of Sporothrix globosa affects the function of THP-1 macrophages and modulates the expression of TLR2 and TLR4

BACKGROUND

Melanin is an important virulence factor for Sporothrix globosa, the causative agent of sporotrichosis, a subcutaneous mycosis that occurs worldwide. Although previous research suggests that melanin is involved in the pathogenesis of sporotrichosis, little is known about its influence on the macrophages that represent the frontline components of innate immunity.

OBJECTIVES

To evaluate the effects of melanin on phagocytic activity and the expression of Toll-like receptor (TLR)2 and TLR4 during S. globosa infection of macrophages in vitro.

METHODS

To compare phagocytic activity and survival rates, THP-1 macrophages and primary mouse peritoneal macrophages were co-cultured with a wild-type S. globosa strain (Mel+), an albino mutant strain (Mel-), a tricyclazole-treated Mel + strain (TCZ-Mel+), or melanin ghosts extracted from S. globosa conidia. Reactive oxygen species (ROS), nitric oxide (NO) generation, tumor necrosis factor (TNF)-α and interleukin (IL)-6 were assayed in THP-1 cells infected with S. globosa conidia. Quantitative PCR and western blotting were used to observe the effect of melanin on TLR2 and TLR4 expression. Knockdown of TLR2/4 expression with small interfering RNA was performed to further verify the role of these receptors during infection.

RESULTS

Macrophages infected with Mel + conidia showed a lower phagocytosis index and a higher survival rate than TCZ-Mel+ and Mel- in vitro. After incubation with S. globosa, the release of ROS, NO, TNF-α and IL-6 by THP-1 were decreased in the presence of melanin. Increased mRNA and protein expression of TLR2 and TLR4 occurred upon S. globosa infection in THP-1, whereas the presence of melanin suppressed TLR2 and TLR4. Moreover, TLR2 or TLR4 knockdown showed a trend toward reducing the pernicious effect of S. globosa conidia on THP-1 cells in vitro.

CONCLUSIONS

Collectively, our results indicated that melanin inhibits the phagocytosis of S. globosa and guards against macrophage attack by providing protection from oxygen- and nitrogen-derived radicals, as well as suppressing the host pro-inflammatory cytokine response (TNF-α and IL-6). Melanin was also involved in modulating TLR2 and TLR4 receptor expression, weakening the killing efficiency of S. globosa.

So close, and yet so far away: The dichotomy of the specific immune response and inflammation in psoriasis and atopic dermatitis

Characterization of the complex interplay between cytokines, chemokines and microorganisms has led to a better understanding of the pathogenesis of both psoriasis and AD and resulted in new therapeutics targeting distinct immune responses. Psoriasis and AD share many characteristics: they are highly prevalent, chronic, cause primarily skin inflammation, but are associated with comorbidities, and come with a devastating quality of life due to itch and stigmatization. However, the pathogenesis of psoriasis and AD is opposing - psoriasis is dominated by a Th17 immune response that causes neutrophil migration, induction of innate immunity and exaggerated epithelial metabolism. Leading cytokines of this Th17 immune response are IL-17A and F, IL-22 and TNF-a. AD is characterized by Th2 immunity characterized by the signature cytokines IL-4 and IL-13 leading to an impaired epidermal barrier, dampened innate immunity and eosinophil migration. This review compares genetics, microbiome and T-cell infiltrate and resulting epithelial response in psoriasis and AD. Whilst the antagonistic course of psoriasis and AD is confirmed by response to specific biologics targeting the key cytokines of inflammation in psoriasis and AD, respectively, clinically overlapping phenotypes are challenging in our daily clinical practice. We conclude this review by summarizing what is known about these mixed phenotypes and how the identification of clinically relevant endotypes and molecular-driven decision-making is the next step in the field of dermato-immunology.

The Interactions Between Candida albicans and Mucosal Immunity

Mucosa protects the body against external pathogen invasion. However, pathogen colonies on the mucosa can invade the mucosa when the immunosurveillance is compromised, causing mucosal infection and subsequent diseases. Therefore, it is necessary to timely and effectively monitor and control pathogenic microorganisms through mucosal immunity. Candida albicans is the most prevalent fungi on the mucosa. The C. albicans colonies proliferate and increase their virulence, causing severe infectious diseases and even death, especially in immunocompromised patients. The normal host mucosal immune defense inhibits pathogenic C. albicans through stepwise processes, such as pathogen recognition, cytokine production, and immune cell phagocytosis. Herein, the current advances in the interactions between C. albicans and host mucosal immune defenses have been summarized to improve understanding on the immune mechanisms against fungal infections.

Characterization of membrane-bound IL-22+ T cell subsets in HIV-1 patients coinfected with Mycobacterium tuberculosis

BACKGROUND

Previously, we have found that IL-22 could be not only secreted outside of cells, but also highly expressed on the T cells membrane in HIV-1 negative patients with tuberculosis (TB). However, the study on membrane-bound IL-22+ cells of HIV-1 infected patients is rare. Therefore, we investigated antigen-specific membrane-bound IL-22+ T cell subsets in Mycobacterium tuberculosis (M.tb) coinfection of HIV-1 infected individuals.

METHODS

A case-control study that enrolled 74 HIV-1 infected participants was carried out, including HIV-1 monoinfection (HIV+TB-, n = 43), HIV-1 infected patients with latent TB (HIV+LTB, n = 18) and HIV-1 coinfected patients with active TB (HIV+TB+, n = 13). We made use of an IFN-γ release assay (IGRA) to screen LTB individuals. Purified protein derivative (PPD) and phosphoantigen (E)-4-hydroxy-3-methyl-but-2-enyl pyrophosphate (HMBPP) were used as specific-stimulators to detect the levels of peripheral blood membrane-bound IL-22+ T cell subsets via cell surface staining and flow cytometry among three groups.

RESULTS

An approximate rate of 24.3% (n = 18 out of 74) of latent M.tb infection among HIV-1 positive population in Eastern China. Interestingly, HMBPP-specific CD3+Vγ2+ T cells were impaired in HIV+TB+patients compared with HIV+LTB patients (P < 0.05). Furthermore, increases of PPD-specific and HMBPP-specific membrane-bound IL-22+ T cell subsets including CD3+, CD3+CD4+ and CD3+Vγ2+ T cells were observed in HIV+TB+group rather than HIV+LTB groups (all P < 0.05).

CONCLUSION

Antigen-specific membrane-bound IL-22+ T cells were highly expressed in M.tb coinfection of HIV-1 infected individuals, and may play an important role in anti-TB immune response during coinfection with HIV-1.

The impact of the Fungus-Host-Microbiota interplay upon Candida albicans infections: current knowledge and new perspectives

Candida albicans is a major fungal pathogen of humans. It exists as a commensal in the oral cavity, gut or genital tract of most individuals, constrained by the local microbiota, epithelial barriers and immune defences. Their perturbation can lead to fungal outgrowth and the development of mucosal infections such as oropharyngeal or vulvovaginal candidiasis, and patients with compromised immunity are susceptible to life-threatening systemic infections. The importance of the interplay between fungus, host and microbiota in driving the transition from C. albicans commensalism to pathogenicity is widely appreciated. However, the complexity of these interactions, and the significant impact of fungal, host and microbiota variability upon disease severity and outcome, are less well understood. Therefore, we summarise the features of the fungus that promote infection, and how genetic variation between clinical isolates influences pathogenicity. We discuss antifungal immunity, how this differs between mucosae, and how individual variation influences a person's susceptibility to infection. Also, we describe factors that influence the composition of gut, oral and vaginal microbiotas, and how these affect fungal colonisation and antifungal immunity. We argue that a detailed understanding of these variables, which underlie fungal-host-microbiota interactions, will present opportunities for directed antifungal therapies that benefit vulnerable patients.

Limited Role of Mincle in the Host Defense against Infection with Cryptococcus deneoformans

Cryptococcus deneoformans is an opportunistic fungal pathogen that frequently causes fatal meningoencephalitis in patients with impaired cell-mediated immune responses such as AIDS. Caspase-associated recruitment domain 9 (CARD9) plays a critical role in the host defense against cryptococcal infection, suggesting the involvement of one or more C-type lectin receptors (CLRs). In the present study, we analyzed the role of macrophage-inducible C-type lectin (Mincle), one of the CLRs, in the host defense against C. deneoformans infection. Mincle expression in the lungs of wild-type (WT) mice was increased in the early stage of cryptococcal infection in a CARD9-dependent manner. In Mincle gene-disrupted (Mincle KO) mice, the clearance of this fungus, pathological findings, Th1/Th2 response, and antimicrobial peptide production in the infected lungs were nearly comparable to those in WT mice. However, the production of interleukin-22 (IL-22), tumor necrosis factor alpha (TNF-α), and IL-6 and the expression of AhR were significantly decreased in the lungs of Mincle KO mice compared to those of WT mice. In in vitro experiments, TNF-α production by bone marrow-derived dendritic cells was significantly decreased in Mincle KO mice. In addition, the disrupted lysates of C. deneoformans, but not those of whole yeast cells, activated Mincle-triggered signaling in an assay with a nuclear factor of activated T cells (NFAT)-green fluorescent protein (GFP) reporter cells expressing this receptor. These results suggest that Mincle may be involved in the production of Th22-related cytokines at the early stage of cryptococcal infection, although its role may be limited in the host defense against infection with C. deneoformans.

Cytokinocytes: the diverse contribution of keratinocytes to immune responses in skin

The skin serves as the primary interface between our body and the external environment and acts as a barrier against entry of physical agents, chemicals, and microbes. Keratinocytes make up the main cellular constitute of the outermost layer of the skin, contributing to the formation of the epidermis, and they are crucial for maintaining the integrity of this barrier. Beyond serving as a physical barrier component, keratinocytes actively participate in maintaining tissue homeostasis, shaping, amplifying, and regulating immune responses in skin. Keratinocytes act as sentinels, continuously monitoring changes in the environment, and, through microbial sensing, stretch, or other physical stimuli, can initiate a broad range of inflammatory responses via secretion of various cytokines, chemokines, and growth factors. This diverse function of keratinocytes contributes to the highly variable clinical manifestation of skin immune responses. In this Review, we highlight the highly diverse functions of epidermal keratinocytes and their contribution to various immune-mediated skin diseases.

Cellular scars and local crosstalk in relapsing psoriasis: an example of a skin sticking disease

Psoriasis is an inflammatory disease that arises in genetically predisposed individuals. Chronic skin lesions that contain activated immune cells can persist for years. Systemic inhibition of TNF, IL‐17 and IL‐23 cytokines has revolutionized psoriasis care during the recent decades. Unfortunately, local relapse of disease is common at previously inflamed sites after cessation of treatment. This highlights that fundamental pathologic alterations of the affected tissues are not completely resolved during clinical remission. Here, we present arguments for a local disease memory located in both dermis and epidermis in psoriasis skin. We decipher different cellular components and intercellular crosstalk that sustain local disease memory and amplify disease relapse in human psoriasis. Decrypting the mechanisms underlying the establishment and persistence of pathogenic memory cells in resolved psoriasis may provide new therapeutic perspectives aimed at long‐term remission of psoriasis.

Formulation and Characterization of Sertaconazole Nitrate Mucoadhesive Liposomes for Vaginal Candidiasis

Purpose

The aim of this study is to develop efficient localized therapy of sertaconazole nitrate for the treatment of vaginal candidiasis.

Methods

Sertaconazole nitrate-loaded cationic liposomes were prepared by thin-film hydration method and coated with different concentrations of pectin (0.05%, 0.1% and 0.2%) to develop mucoadhesive liposomes. The formulated mucoadhesive vesicles were characterized in terms of morphology, entrapment efficiency, particle size, zeta value, mucoadhesive properties and drug release. The selected formula was incorporated into a gel base and further characterized by an ex vivo permeation study in comparison with conventional sertaconazole gel. Also, the in vivo study was performed to assess the efficacy of sertaconazole mucoadhesive liposomal gel in treating rats with vaginal candidiasis.

Results

The mucoadhesive liposomes were spherical. Coating liposomes with pectin results in increased entrapment efficiency and particle size compared with uncoated vesicles. On the contrary, zeta values were reduced upon coating liposomes with pectin indicating efficient coating of liposomes with pectin. Mucoadhesive liposomes showed a more prolonged and sustained drug release compared with uncoated liposomes. Ex vivo study results showed that mucoadhesive liposomal gel increased sertaconazole tissue retention and reduced drug tissue penetration. In the invivo study, the mucoadhesive liposomal gel showed a significant reduction in the microbial count with a subsequent reduction in inflammatory responses with the lowest histopathological change compared with conventional gel.

Conclusion

The study confirmed the potentiality of employing mucoadhesive liposomes as a successful carrier for the vaginal delivery of antifungal drugs.

Diagnostic efficacy of serum cytokines and chemokines in patients with candidemia and bacteremia

BACKGROUND

The role of serum cytokines/chemokines in differential diagnosis between fungal infections and bacterial infections have not been fully understood. This study aims to measure the serum levels of cytokines/chemokines in cases of candidemia and to compare them with those observed in cases of bacteremia.

MATERIAL AND METHODS

Patients with febrile episodes and were identified as bloodstream infections through blood culture were enrolled, while healthy people were included as control group. Fourteen serum cytokine and chemokine levels were detected with multiplex platform. ROC analysis was performed and an area under the curve (AUC), sensitivity and specificity values were calculated to determine the efficacy of various cytokines and chemokines for candidemia and bacteremia. Binary logistic regression was performed to further explore the combination mode of cytokines and chemokines, which could increase the diagnostic efficiency.

RESULTS

We included 40 patients with an episode of microbiologically proven fungal infection, 175 patients with bacteremia (85 with Gram-positive bacteremia and 90 with Gram-negative bacteremia) and another 30 healthy controls. Routine laboratory parameters including CRP and PCT were not statistically significant between candidemia group and bacteremia group (both gram-positive and gram-negative). There were significantly higher levels of IFN-γ, TNF-α, IL-10 and lower levels of IL-3, IL-4 in candidemia group, compared with gram-positive and gram-negative bacteremia groups. G-CSF was significantly lower and MIP-1β was higher in candidemia group, when compared with gram-negative bacteremia group. While IL-6, IL-8 and IL-17 were all significantly higher in candidemia group, when compared with gram-positive bacteremia group. Combination of IFN-γ and IL-17 could improve the diagnostic efficiency between candidemia and gram-positive bacteremia, with the AUROC of 0.873 (95% CI: 0.767-0.929). While combination of G-CSF and MIP-1β improved the diagnostic efficiency between candidemia and gram-negative bacteremia, with the AUROC of 0.896 (95% CI: 0.792-0.939).

CONCLUSION

Our study demonstrates that serum cytokines and chemokines including IFN-γ, MIP-1β, IL-17 and G-CSF could be considered as diagnostic markers to distinguish between candidemia and bacteremia. Combination of these biomarkers might improve the diagnostic efficiency of candidemia when compared with bacteremia.

Implication of the p53-Related miR-34c, -125b, and -203 in the Osteoblastic Differentiation and the Malignant Transformation of Bone Sarcomas

The formation of the skeleton occurs throughout the lives of vertebrates and is achieved through the balanced activities of two kinds of specialized bone cells: the bone-forming osteoblasts and the bone-resorbing osteoclasts. Impairment in the remodeling processes dramatically hampers the proper healing of fractures and can also result in malignant bone diseases such as osteosarcoma. MicroRNAs (miRNAs) are a class of small non-coding single-strand RNAs implicated in the control of various cellular activities such as proliferation, differentiation, and apoptosis. Their post-transcriptional regulatory role confers on them inhibitory functions toward specific target mRNAs. As miRNAs are involved in the differentiation program of precursor cells, it is now well established that this class of molecules also influences bone formation by affecting osteoblastic differentiation and the fate of osteoblasts. In response to various cell signals, the tumor-suppressor protein p53 activates a huge range of genes, whose miRNAs promote genomic-integrity maintenance, cell-cycle arrest, cell senescence, and apoptosis. Here, we review the role of three p53-related miRNAs, miR-34c, -125b, and -203, in the bone-remodeling context and, in particular, in osteoblastic differentiation. The second aim of this study is to deal with the potential implication of these miRNAs in osteosarcoma development and progression.

The immunopathogenesis of tuberculous pericarditis

Tuberculous pericarditis is a severe form of extrapulmonary tuberculosis and is the commonest cause of pericardial effusion in high incidence settings. Mortality ranges between 8 and 34%, and it is the leading cause of pericardial constriction in Africa and Asia. Current understanding of the disease is based on models derived from studies performed in the 1940-50s. This review summarises recent advances in the histology, microbiology and immunology of tuberculous pericarditis, with special focus on the effect of Human Immunodeficiency Virus (HIV) and the determinants of constriction.

Diagnostic efficacy of serum cytokines and chemokines in fungal bloodstream infection in febrile patients

BACKGROUND

The role of serum cytokines/chemokines in early diagnosis of fungal infections has not been clearly clarified yet. This study aims to measure the serum levels of cytokines/chemokines in cases of fungemia and to compare them with culture-negative controls.

METHODS

In total, fourteen types of serum cytokines and chemokines from 41 patients with fungemia were compared with 57 patients with negative blood culture results. The cytokine and chemokine levels were detected with multiplex platform. We then performed statistical analysis as a two-tailed P < .05. ROC analysis was performed, and an area under the curve (AUC), and sensitivity and specificity values were calculated to determine the efficacy of various cytokines and chemokines for fungemia. Binary logistic regression was performed to further explore the combination mode of cytokines and chemokines, which could increase the diagnostic efficiency.

RESULTS

C-reactive protein and procalcitonin were significantly higher compared with those in negative control group, while white blood cell, percentage of neutrophil, percentage of lymphocyte, and ratio of neutrophil and lymphocyte did not differentiate between two groups. Serum levels of IFN-γ, TNF-α, MIP-1β, IL-6, IL-8, IL-10, IL-12p70, and IL-17 were significantly higher in patients with fungemia compared with the control group. Combination of MIP-1β and IL-17 could improve the AUC, sensitivity, and specificity for the diagnosis of fungemia.

CONCLUSION

Our study demonstrates that serum cytokines and chemokines including IFN-γ, TNF-α, MIP-1β, IL-6, IL-8, IL-10, IL-12p70, and IL-17 could be considered as diagnostic markers for fungemia. Combination of these biomarkers might improve the diagnostic efficiency of fungemia.

A new T helper 17 cytokine in hidradenitis suppurativa: antimicrobial and proinflammatory role of interleukin-26

BACKGROUND

Interleukin (IL)-26 is a signature T helper 17 cytokine described as a proinflammatory and antimicrobial mediator. So far, IL-26 has been reported in several immune-mediated inflammatory diseases, but its involvement in inflammatory skin disorders is poorly known.

OBJECTIVES

To investigate the role of IL-26 in hidradenitis suppurativa (HS), through its involvement in antimicrobial activity.

METHODS

IL-26 was assessed in patients with HS through gene expression and protein analysis at skin and circulating levels. Ex vivo HS organ skin cultures, together with IL-26 antibody treatment, were performed to determine the IL-26 activity. Peripheral blood mononuclear cells (PBMCs) from patients with HS and healthy controls were either silenced or not with IL-26 small interfering (si)RNA in order to measure its antimicrobial, cytotoxic and phagocytic activities against Staphylococcus aureus.

RESULTS

Firstly, we observed that IL-26 is able to modulate the proinflammatory response at the immune cell level. IL-26 was increased in the plasma of patients with HS compared with healthy controls. Subsequently, we explored the bactericidal, cytotoxic and phagocytic activities of PBMCs against S. aureus in patients with HS and healthy controls. These activities were lower in patients with HS than in controls. Remarkably, the killing activities were reduced when healthy control PBMCs were transfected with IL-26 siRNA. However, the transfection did not affect the killing activity of HS PBMCs, supporting the idea that IL-26 lacks efficacy in HS.

CONCLUSIONS

Our findings suggest that infection susceptibility in HS might be related to IL-26. Although the role of bacteria remains controversial in HS, this paper supports that there is a defect of antimicrobial response in these patients. What's already known about this topic? Interleukin (IL)-26 is a T helper 17 cytokine described as an antimicrobial and proinflammatory mediator. IL-26 has been reported in immune-mediated inflammatory diseases, but its involvement in inflammatory skin disorders remains unclear. Hidradenitis suppurativa (HS) is a chronic inflammatory skin disorder characterized by deficiency of IL-20 and IL-22 (a close homologue of IL-26), which causes antimicrobial peptide pauperization leading to severe and recurrent skin infections. What does this study add? IL-26 plasma levels are higher in patients with HS than in healthy control individuals. The antimicrobial activity of IL-26 might be ineffective in patients with HS. What is the translational message? Cutaneous antimicrobial incompetence in HS could be related to IL-26.

IL-22 promotes allergic airway inflammation in epicutaneously sensitized mice

BACKGROUND

Serum IL-22 levels are increased in patients with atopic dermatitis, which commonly precedes asthma in the atopic march. Epicutaneous sensitization in mice results in TH2-dominated skin inflammation that mimics atopic dermatitis and sensitizes the airways for antigen challenge-induced allergic inflammation characterized by the presence of both eosinophils and neutrophils. Epicutaneous sensitization results in increased serum levels of IL-22.

OBJECTIVE

We sought to determine the role of IL-22 in antigen-driven airway allergic inflammation after inhalation challenge in epicutaneously sensitized mice.

METHODS

Wild-type (WT) and Il22-/- mice were sensitized epicutaneously or immunized intraperitoneally with ovalbumin (OVA) and challenged intranasally with antigen. OVA T-cell receptor-specific T cells were TH22 polarized in vitro. Airway inflammation, mRNA levels in the lungs, and airway hyperresponsiveness (AHR) were examined.

RESULTS

Epicutaneous sensitization preferentially elicited an IL-22 response compared with intraperitoneal immunization. Intranasal challenge of mice epicutaneously sensitized with OVA elicited in the lungs Il22 mRNA expression, IL-22 production, and accumulation of CD3+CD4+IL-22+ T cells that coexpressed IL-17A and TNF-α. Epicutaneously sensitized Il22-/- mice exhibited diminished eosinophil and neutrophil airway infiltration and decreased AHR after intranasal OVA challenge. Production of IL-13, IL-17A, and TNF-α was normal, but IFN-γ production was increased in lung cells from airway-challenged and epicutaneously sensitized Il22-/- mice. Intranasal instillation of IFN-γ-neutralizing antibody partially reversed the defect in eosinophil recruitment. WT recipients of TH22-polarized WT, but not IL-22-deficient, T-cell receptor OVA-specific T cells, which secrete both IL-17A and TNF-α, had neutrophil-dominated airway inflammation and AHR on intranasal OVA challenge. Intranasal instillation of IL-22 with TNF-α, but not IL-17A, elicited neutrophil-dominated airway inflammation and AHR in WT mice, suggesting that loss of IL-22 synergy with TNF-α contributed to defective recruitment of neutrophils into the airways of Il22-/- mice. TNF-α, but not IL-22, blockade at the time of antigen inhalation challenge inhibited airway inflammation in epicutaneously sensitized mice.

CONCLUSION

Epicutaneous sensitization promotes generation of antigen-specific IL-22-producing T cells that promote airway inflammation and AHR after antigen challenge, suggesting that IL-22 plays an important role in the atopic march.

Chronic mucocutaneous candidiasis due to gain-of-function mutation in STAT1

Chronic mucocutaneous candidiasis (CMC) is a heterogenous group of primary immunodeficiency diseases characterised by susceptibility to chronic or recurrent superficial Candida infection of skin, nails and mucous membranes. Gain-of-function mutations in the STAT1 gene (STAT1-GOF) are the most common genetic aetiology for CMC, and mutation analysis should be considered. These mutations lead to defective responses in Type 1 and Type 17 helper T cells (Th1 and Th17), which, depending on the mutation, also predispose to infection with Staphylococci, Mycobacteria and Herpesviridae. We describe the clinical and genetic findings for three patients with CMC due to gain-of-function mutations in the STAT1 gene.

The Role of AIRE in the Immunity Against Candida Albicans in a Model of Human Macrophages

Autoimmune-polyendocrinopathy-candidiasis-ectodermal dystrophy (APECED) is a primary immunodeficiency caused by mutations in the autoimmune regulator gene (AIRE). Patients with AIRE mutations are susceptible to Candida albicans infection and present with autoimmune disorders. We previously demonstrated that cytoplasmic AIRE regulates the Syk-dependent Dectin-1 pathway. In this study, we further evaluated direct contact with fungal elements, synapse formation, and the response of macrophage-like THP-1 cells to C. albicans hyphae to determine the role of AIRE upon Dectin receptors function and signaling. We examined the fungal synapse (FS) formation in wild-type and AIRE-knockdown THP-1 cells differentiated to macrophages, as well as monocyte-derived macrophages from APECED patients. We evaluated Dectin-2 receptor signaling, phagocytosis, and cytokine secretion upon hyphal stimulation. AIRE co-localized with Dectin-2 and Syk at the FS upon hyphal stimulation of macrophage-like THP-1 cells. AIRE-knockdown macrophage-like THP-1 cells exhibited less Dectin-1 and Dectin-2 receptors accumulation, decreased signaling pathway activity at the FS, lower C. albicans phagocytosis, and less lysosome formation. Furthermore, IL-1β, IL-6, or TNF-α secretion by AIRE-knockdown macrophage-like THP-1 cells and AIRE-deficient patient macrophages was decreased compared to control cells. Our results suggest that AIRE modulates the FS formation and hyphal recognition and help to orchestrate an effective immune response against C. albicans.

Effects of Th17/Treg cell imbalance on HIV replication in patients with AIDS complicated with tuberculosis

The purpose of this study was to determine the effect of Th17/Treg cell imbalance on HIV replication in patients with AIDS complicated with tuberculosis (TB). We selected 32 patients with AIDS combined with TB infection in our hospital and 30 healthy individual as controls. The Th17/Treg ratio in peripheral blood lymphocytes was detected by flow cytometry. Compared with healthy subjects, Th17 cells first declined in HIV patients with TB, but gradually increased over the course of the disease. Treg showed an increasing trend in HIV patients with TB. The Th17/Treg ratio was significantly altered as the condition gradually deteriorated. ELISA showed that interleukin (IL)-17, IL-6 and IL-10 in patients with HIV complicated with TB were significantly lower than in healthy subjects. The imbalance of Th17/Treg cells can promote HIV virus replication in AIDS patients with TB infection, which can aggravate the condition.

Patient Susceptibility to Candidiasis-A Potential for Adjunctive Immunotherapy

Candida spp. are colonizing fungi of human skin and mucosae of the gastrointestinal and genitourinary tract, present in 30-50% of healthy individuals in a population at any given moment. The host defense mechanisms prevent this commensal fungus from invading and causing disease. Loss of skin or mucosal barrier function, microbiome imbalances, or defects of immune defense mechanisms can lead to an increased susceptibility to severe mucocutaneous or invasive candidiasis. A comprehensive understanding of the immune defense against Candida is essential for developing adjunctive immunotherapy. The important role of underlying genetic susceptibility to Candida infections has become apparent over the years. In most patients, the cause of increased susceptibility to fungal infections is complex, based on a combination of immune regulation gene polymorphisms together with other non-genetic predisposing factors. Identification of patients with an underlying genetic predisposition could help determine which patients could benefit from prophylactic antifungal treatment or adjunctive immunotherapy. This review will provide an overview of patient susceptibility to mucocutaneous and invasive candidiasis and the potential for adjunctive immunotherapy.

Knockout of autophagy gene, ATG5 in mice vaginal cells abrogates cytokine response and pathogen clearance during vaginal infection of Candida albicans

The female reproductive tract (FRT) presents a unique challenge to the mucosal immune system as it needs to monitor constantly for the presence of opportunistic pathogens amidst its commensal flora. During infection, autophagy plays a critical role in pathogen clearance, presentation of antigens and production of pro-inflammatory cytokines. However, no information is available that describes the role of autophagy in mouse vaginal infection of Candida albicans. The objective of our study is to evaluate the effect of autophagy gene, ATG5 knockout in vaginal cells in response to vaginal C. albicans infection. Mice having knockout of ATG5 in the vaginal cells (PR-ATG5-KO mice) were infected intra-vaginally with the yeast form of Candida albicans. Vaginal lavages were collected once in a week until the infection was cleared. We detected the expression of autophagy marker genes (LC3, ATG5 and LAMP1) in the vaginal cells. We determined the levels of various cytokines (IL-1α, IL-1β, IL-6, IL-10, IL-17A, IL-22, IL-23p19, TNF-α and G-CSF) involved in anti-candida response. The levels of cytokines in the vaginal lavages were quantified using Aimplex Premixed analyte kit. The vaginal lavages were checked for polymorphonuclear leucocytes (PMNLs) infiltration. The candida clearance rate from the vaginal lumen was determined by Colony Forming Units (CFUs) assay. The results revealed that PR-ATG5-KO mice failed to induce the expression of LC3, ATG5 and LAMP1 indicating an impaired autophagy pathway. The levels of all the cytokines (except IL-10) in C. albicans infected PR-ATG5-KO mice were significantly reduced as compared to the wild type infected C57BL/6 mice. The number of PMNLs infiltrated into the vaginal lavages of infected PR-ATG5-KO mice was reduced. The clearance of C. albicans from the vaginal lumen was also considerably delayed in PR-ATG5-KO mice. In conclusion, the results revealed that impaired autophagy in vaginal cells influences host response during vaginal infection of C. albicans by affecting anti-Candida cytokine levels in the vaginal lavage resulting in reduction of pathogen clearance rate.

Impaired Specific Antifungal Immunity in CARD9-Deficient Patients with Phaeohyphomycosis

Phaeohyphomycosis is a group of severe infections caused by dematiaceous fungi. We previously identified CARD9 deficiencies in four Chinese patients with phaeohyphomycosis caused by Phialophora verrucosa. In this study, we sought to identify the genetic and immunological mechanisms underlying rare dematiaceous fungal infections in three otherwise healthy patients with phaeohyphomycosis caused by Exophiala spinifera, Ochroconis musae, and Corynespora cassiicola. CARD9 sequencing in these patients showed one mutation (p.S23X) that, to our knowledge, has not been characterized and two previously characterized mutations (p.D274fsX60 and p.L64fsX59) that led to lack of CARD9 protein expression. Patient-derived CARD9-deficient cells showed a selective impairment of proinflammatory cytokine and chemokine production, NF-κB activation, and T helper type 22- and T helper type 17-associated responses upon fungus-specific stimulation, whereas phagocytosis and reactive oxygen species production were intact. Consistently, Card9-knockout mice were highly susceptible to phaeohyphomycosis and exhibited immune deficiencies similar to those of patients, including diminished NF-κB and p38 MAPK activation in local and in vitro functional studies. This work clarifies the association between inherited CARD9 deficiencies and phaeohyphomycosis, and furthers current knowledge on the spectrum and pathophysiology of diseases resulting from CARD9 deficiencies.

Role of mesenchymal stem cells in the pathogenesis of psoriasis: current perspectives

Mesenchymal stem cells (MSCs) are multipotent nonhematopoietic stromal cells studied for their properties and importance in management of several skin diseases. This review collects and analyzes the emerging published data, which describe the function of MSCs in the pathogenesis of psoriasis.

Interaction of Candida Species with the Skin

The human skin is commonly colonized by diverse fungal species. Some Candida species, especially C. albicans, do not only reside on the skin surface as commensals, but also cause infections by growing into the colonized tissue. However, defense mechanisms at the skin barrier level are very efficient, involving residential non-immune and immune cells as well as immune cells specifically recruited to the site of infection. Therefore, the skin is an effective barrier against fungal infection. While most studies about commensal and pathogenic interaction of Candida species with host epithelia focus on the interaction with mucosal surfaces such as the vaginal and gastrointestinal epithelia, less is known about the mechanisms underlying Candida interaction with the skin. In this review, we focus on the ecology and molecular pathogenesis of Candida species on the skin and give an overview of defense mechanisms against C. albicans in this context. We also discuss new research avenues in dermal infection, including the involvement of neurons, fibroblasts, and commensal bacteria in both mouse and human model systems.

Linking the Human Gut Microbiome to Inflammatory Cytokine Production Capacity

Gut microbial dysbioses are linked to aberrant immune responses, which are often accompanied by abnormal production of inflammatory cytokines. As part of the Human Functional Genomics Project (HFGP), we investigate how differences in composition and function of gut microbial communities may contribute to inter-individual variation in cytokine responses to microbial stimulations in healthy humans. We observe microbiome-cytokine interaction patterns that are stimulus specific, cytokine specific, and cytokine and stimulus specific. Validation of two predicted host-microbial interactions reveal that TNFα and IFNγ production are associated with specific microbial metabolic pathways: palmitoleic acid metabolism and tryptophan degradation to tryptophol. Besides providing a resource of predicted microbially derived mediators that influence immune phenotypes in response to common microorganisms, these data can help to define principles for understanding disease susceptibility. The three HFGP studies presented in this issue lay the groundwork for further studies aimed at understanding the interplay between microbial, genetic, and environmental factors in the regulation of the immune response in humans. PAPERCLIP.

Immunoresponses in dermatomycoses

Contact with fungal pathogens initiates a series of host responses beginning with innate immunity, which leads to fungal recognition and microbial killing. The innate immune system also modulates the adaptive immune responses, leading to the establishment of immunological memory and protection against pathogens. In the case of dimorphic fungi such as Candida albicans and Malassezia, the immune system plays an important role in tolerance and resistance when managing the organisms either as commensal microbiota or invading pathogens, and disruption of this balance can result in pathological consequences for the host. In addition, Malassezia and dermatophytes have immunomodulatory capabilities that allow them to adapt to their environments and they may exert different effects in healthy and diseased skin. Here, we discuss the host immune responses to dermatomycoses caused by dimorphic fungi such as C. albicans and Malassezia as well as dermatophytes such as Trichophyton spp. and Arthroderma benhamiae to gain a better understanding of the mechanisms of the host-dermatomycosis interaction.