MiR-155 is overexpressed in patients with atopic dermatitis and modulates T-cell proliferative responses by targeting cytotoxic T lymphocyte-associated antigen 4

The role of microRNAs in atopic dermatitis

Atopic dermatitis (AD), known as eczema, is a chronic inflammatory skin condition affecting millions worldwide. This abstract provides an overview of the clinical features and underlying pathogenesis of AD, highlighting the role of specific microRNAs (miRNAs) in its development and progression. AD presents with distinct clinical manifestations that evolve with age, starting in infancy with dry, itchy skin and red patches, which can lead to sleep disturbances. In childhood, the rash spreads to flexural areas, resulting in lichenification. In adulthood, lesions may localize to specific areas, including the hands and eyelids. Pruritus (itchiness) is a hallmark symptom, often leading to excoriations and increased vulnerability to skin infections. The pathogenesis of AD is multifaceted, involving genetic, immunological, and environmental factors. Skin barrier dysfunction, immune dysregulation, genetic predisposition, microbiome alterations, and environmental triggers contribute to its development. Recent research has uncovered the role of miRNAs, such as miR-10a-5p, miR-29b, miR-124, miR-143, miR-146a-5p, miR-151a, miR-155, and miR-223, in AD pathogenesis. These microRNAs play crucial roles in regulating various aspects of immune responses, keratinocyte dynamics, and inflammation. MicroRNA-10a-5p orchestrates keratinocyte proliferation and differentiation, while miR-29b regulates keratinocyte apoptosis and barrier integrity. MicroRNA-124 exhibits anti-inflammatory effects by targeting the NF-κB signaling pathway. MicroRNANA-143 counters allergic inflammation by modulating IL-13 signaling. MicroRNA-146a-5p regulates immune responses and correlates with IgE levels in AD. MicroRNA-151a shows diagnostic potential and modulates IL-12 receptor β2. MicroRNA-155 plays a central role in immune responses and Th17 cell differentiation, offering diagnostic and therapeutic potential. MicroRNA-223 is linked to prenatal smoke exposure and immune modulation in AD. Understanding these microRNAs' intricate roles in AD pathogenesis promises more effective treatments, personalized approaches, and enhanced diagnostic tools. Further research into these molecular orchestrators may transform the landscape of AD management, improving the quality of life for affected individuals.

Inflammatory factor-mediated miR-155/SOCS1 signaling axis leads to Treg impairment in systemic lupus erythematosus

BACKGROUND

Systemic lupus erythematosus (SLE) is an autoimmune disorder associated with the decrease and functional impairment of regulatory T cells (Tregs). In the current study, we explored the interplay of miR-155 and suppressor of cytokine signaling 1 (SOCS1) in regulating Treg function and stability in SLE.

METHODS

Clinical samples from healthy subjects and SLE patients were collected, and a mouse model of SLE was established to profile the expression pattern of miR-155 and SCOS1 in Tregs. Tregs isolated from mouse spleen were stimulated by inflammatory cytokines to confirm involvement of miR-155/SOCS1 axis in dictating Treg stability and function. We also administrated synthetic miR-155 inhibitor in SLE animal model to evaluate the potential effect on rescuing Treg function and alleviating SLE progression.

RESULTS

Tregs from SLE patients and SLE-induced mice exhibited a downregulation of SOCS1 and an upregulation of miR-155. In Tregs stimulated by inflammatory cytokines, Nuclear factor kappa B (NF-κB) signaling activation was required for the change of SOCS1 and miR-155 expression. miR-155 served as a negative regulator to dampen SOCS1 expression in inflammation-stimulated Tregs. The transfection of miR-155 mimic impaired the suppressive function and differentiation of Tregs through targeting SOCS1. In contrast, miR-155 inhibition improved Treg function under inflammatory stimulation and alleviated SLE conditions in the mouse model.

CONCLUSION

Inflammation-induced miR-155 impairs Treg stability and function in SLE through decreasing SOCS1 expression. Targeting miR-155 might be developed as an intervention to mitigate SLE conditions.

Immune modulatory microRNAs in tumors, their clinical relevance in diagnosis and therapy

The importance of the immune system in regulating tumor growth by inducing immune cell-mediated cytotoxicity associated with patients' outcomes has been highlighted in the past years by an increasing life expectancy in patients with cancer on treatment with different immunotherapeutics. However, tumors often escape immune surveillance, which is accomplished by different mechanisms. Recent studies demonstrated an essential role of small non-coding RNAs, such as microRNAs (miRNAs), in the post-transcriptional control of immune modulatory molecules. Multiple methods have been used to identify miRNAs targeting genes involved in escaping immune recognition including miRNAs targeting CTLA-4, PD-L1, HLA-G, components of the major histocompatibility class I antigen processing machinery (APM) as well as other immune response-relevant genes in tumors. Due to their function, these immune modulatory miRNAs can be used as (1) diagnostic and prognostic biomarkers allowing to discriminate between tumor stages and to predict the patients' outcome as well as response and resistance to (immuno) therapies and as (2) therapeutic targets for the treatment of tumor patients. This review summarizes the role of miRNAs in tumor-mediated immune escape, discuss their potential as diagnostic, prognostic and predictive tools as well as their use as therapeutics including alternative application methods, such as chimeric antigen receptor T cells.

Atopic Dermatitis and Autism Spectrum Disorders: Common Role of Environmental and Clinical Co-Factors in the Onset and Severity of Their Clinical Course

Increasing evidence suggests an association between atopic dermatitis, the most chronic inflammatory disease of the skin, and autism spectrum disorders, which are a group of neurodevelopmental diseases. Inflammation and immune dysregulation associated with genetic and environmental factors seem to characterize the pathophysiological mechanisms of both conditions. We conducted a literature review of the PubMed database aimed at identifying the clinical features and alleged risk factors that could be used in clinical practice to predict the onset of ASD and/or AD or worsen their prognosis in the context of comorbidities.

Characterization of Inflammatory Mediators and Metabolome in Interstitial Fluid Collected with Dermal Open Flow Microperfusion before and at the End of Dupilumab Treatment in Atopic Dermatitis

Dupilumab is a monoclonal antibody approved for the treatment of atopic dermatitis (AD); however, its effects on molecular, cellular, and immunological levels remain to be elucidated. In this study, blood and dermal interstitial fluid (ISF) from nonlesional (NL) and lesional (L) skin were collected from eight patients with moderate to severe AD, before (visit 2-v2) and at the end of a 16-week treatment with dupilumab (visit 10-v10). Clinical treatment effect was demonstrated by significantly decreased AD severity scores at the end of treatment. At v10 versus v2, the percentages of CD4+ interleukin-producing cells showed a decreasing trend in ISF L and NL, unbound IL-4 levels in plasma were increased, IL-5 levels in ISF L reduced, and levels of factors involved in anti-inflammatory pathways and re-epithelization increased. At v2, ISF L showed that AD lesions might have altered amino acid pathways and lipid signaling compared to ISF NL. At v10, ISF L exhibited raised levels of long- and very-long-chain fatty acids and lipids compared to v2. Furthermore, dupilumab administration caused reduced expression of miR-155-5p and miR-378a-3p in ISF L. In conclusion, results from the present study provided novel knowledge by linking local immune and metabolic alterations to AD pathogenesis and treatment response.

Non-coding RNAs as skin disease biomarkers, molecular signatures, and therapeutic targets

Non-coding RNAs (ncRNAs) are emerging as biomarkers, molecular signatures, and therapeutic tools and targets for diseases. In this review, we focus specifically on skin diseases to highlight how two classes of ncRNAs-microRNAs and long noncoding RNAs-are being used to diagnose medical conditions of unclear etiology, improve our ability to guide treatment response, and predict disease prognosis. Furthermore, we explore how ncRNAs are being used as both as drug targets and associated therapies have unique benefits, risks, and challenges to development, but offer a distinctive promise for improving patient care and outcomes.

MicroRNA-939 amplifies Staphylococcus aureus-induced matrix metalloproteinase expression in atopic dermatitis

Background

Atopic dermatitis (AD) is a common chronic inflammatory skin diseases that seriously affects life quality of the patients. Staphylococcus aureus (S. aureus) colonization on the skin plays an important role in the pathogenesis of AD; however, the mechanism of how it modulates skin immunity to exacerbate AD remains unclear. MicroRNAs are short non-coding RNAs that act as post-transcriptional regulators of genes. They are involved in the pathogenesis of various inflammatory skin diseases.

Methods

In this study, we established miRNA expression profiles for keratinocytes stimulated with heat-killed S. aureus (HKSA). The expression of miR-939 in atopic dermatitis patients was analyzed by fluorescence in situ hybridization (FISH). miR-939 mimic was transfected to human primary keratinocyte to investigate its impact on the expression of matrix metalloproteinase genes (MMPs) in vitro. Subsequently, miR-939, along with Polyplus transfection reagent, was administered to MC903-induced atopic dermatitis skin to assess its function in vivo.

Results

MiR-939 was highly upregulated in HKSA-stimulated keratinocytes and AD lesions. In vitro studies revealed that miR-939 increased the expression of matrix metalloproteinase genes, including MMP1, MMP3, and MMP9, as well as the cell adhesion molecule ICAM1 in human primary keratinocytes. In vivo studies indicated that miR-939 increased the expression of matrix metalloproteinases to promote the colonization of S. aureus and exacerbated S. aureus-induced AD-like skin inflammation.

Conclusions

Our work reveals miR-939 is an important regulator of skin inflammation in AD that could be used as a potential therapeutic target for AD.

Acidic fibroblast growth factor inhibits reactive oxygen species-induced epithelial-mesenchymal transdifferentiation in vascular endothelial cells via the miR-155-5p/SIRT1/Nrf2/HO-1 pathway to promote wound healing in diabetic mice

Background

Diabetic chronic wounds are among the most common and serious complications of diabetes and are associated with significant morbidity and mortality. Endothelial-to-mesenchymal transition (EndMT) is a specific pathological state in which endothelial cells are transformed into mesenchymal cells in response to various stimuli, such as high glucose levels and high oxidative stress. Acidic fibroblast growth factor (aFGF), which is a member of the fibroblast growth factor family, possesses strong antioxidant properties and can promote the differentiation of mesenchymal stem cells into angiogenic cells. Therefore, we investigated the role of aFGF in EndMT in diabetic wounds and analysed the underlying mechanisms.

Methods

A diabetic mouse model was used to verify the effect of aFGF on wound healing, and the effect of aFGF on vascular endothelial cells in a high-glucose environment was examined in vitro. We examined the expression of miR-155-5p in a high-glucose environment and the miR-155 downstream target gene SIRT1 by luciferase reporter assays.

Results

aFGF promoted wound closure and neovascularization in a mouse model of type 2 diabetes. In vitro, aFGF inhibited the production of total and mitochondrial reactive oxygen species (ROS) in vascular endothelial cells and alleviated epithelial-mesenchymal transdifferentiation in a high-glucose environment. Mechanistically, aFGF promoted the expression of SIRT1 and the downstream targets Nrf2 and HO-1 by negatively regulating miR-155-5p, thereby reducing ROS generation.

Conclusions

In conclusion, our results suggest that aFGF inhibits ROS-induced epithelial-mesenchymal transdifferentiation in diabetic vascular endothelial cells via the miR-155-5p/SIRT1/Nrf2/HO-1 axis, thereby promoting wound healing.

WTAP-Mediated N6-Methyladenosine of RNAs Facilitate the Pathophysiology of Atopic Dermatitis

N6-methyladenosine (m6A) is the most abundant dynamic and reversible internal chemical modification of RNA in eukaryotic cells and is essential in multiple pathophysiological processes. However, it has not been reported in atopic dermatitis (AD). We used Arraystar m6A-mRNA epitranscriptomic microarray to screen for differentially expressed genes and their m6A levels and m6A-related enzymes in patients with AD. We confirmed that the m6A RNA methyltransferase WTAP and 2 candidate differentially expressed genes (S100A9 and SERPINB3) were significantly upregulated in keratinocytes in public data and epidermal lesions of patients with AD. In vitro cell experiments confirmed that WTAP influenced the expression of the 2 candidate differentially expressed genes and promoted primary human epidermal keratinocyte proliferation while inhibiting human epidermal keratinocyte differentiation. Furthermore, we showed that WTAP, S100A9, and SERPINB3 expression correlated with AD severity. Our findings revealed that WTAP-mediated m6A modification promoted the expression of S100A9 and SERPINB3 to aggravate human epidermal keratinocyte proliferation and dysdifferentiation contributing to the pathophysiological development of AD.

Lung proinflammatory microRNA and cytokine expression in a mouse model of allergic inflammation: role of sex chromosome complement and gonadal hormones

Epigenetic alterations such as dysregulation of miRNAs have been reported to play important roles in interactions between genetic and environmental factors. In this study, we tested the hypothesis that induction of lung inflammation by inhaled allergens triggers a sex-specific miRNA regulation that is dependent on chromosome complement and hormonal milieu. We challenged the four core genotypes (FCGs) model through intranasal sensitization with a house dust mite (HDM) solution (or PBS as a control) for 5 wk. The FCG model allows four combinations of gonads and sex chromosomes: 1) XX mice with ovaries (XXF), 2) XY mice with testes (XYM), 3) XX mice with testes (XXM), and 4) XY mice with ovaries (XYF). Following the challenge (n = 5-7/group), we assessed the expression of 84 inflammatory miRNAs in lung tissue using a PCR array and cytokine levels in bronchoalveolar lavage fluid (BAL) by a multiplex protein assay (n = 4-7 animals/group). Our results showed higher levels of the chemokine KC (an Il-8 homolog) and IL-7 in BAL from XYF mice challenged with HDM. In addition, IL-17A was significantly higher in BAL from both XXF and XYF mice. A three-way interaction among treatment, gonads, and sex chromosome revealed 60 of 64 miRNAs that differed in expression depending on genotype; XXF, XXM, XYF, and XYM mice had 45, 32, 4, and 52 differentially expressed miRNAs, respectively. Regulatory networks of miRNAs identified in this study were implicated in pathways associated with asthma. Female gonadal hormonal effects may alter miRNA expression and contribute to the higher susceptibility of females to asthma.NEW & NOTEWORTHY miRNAs play important roles in regulating gene and environmental interactions. However, their role in mediating sex differences in allergic responses and lung diseases has not been elucidated. Our study used a targeted omics approach to characterize the contributions of gonadal hormones and chromosomal components to lung responses to an allergen challenge. Our results point to the influence of sex hormones in miRNA expression and proinflammatory markers in allergic airway inflammation.

The role of intestinal flora on tumor immunotherapy: recent progress and treatment implications

Immunotherapy, specifically immune checkpoint inhibitors, has emerged as a promising approach for treating malignant tumors. The gut, housing approximately 70 % of the body's immune cells, is abundantly populated with gut bacteria that actively interact with the host's immune system. Different bacterial species within the intestinal flora are in a delicate equilibrium and mutually regulate each other. However, when this balance is disrupted, pathogenic microorganisms can dominate, adversely affecting the host's metabolism and immunity, ultimately promoting the development of disease. Emerging researches highlight the potential of interventions such as fecal microflora transplantation (FMT) to improve antitumor immune response and reduce the toxicity of immunotherapy. These remarkable findings suggest the major role of intestinal flora in the development of cancer immunotherapy and led us to the hypothesis that intestinal flora transplantation may be a new breakthrough in modifying immunotherapy side effects.

Multi-Omics Approach to Improved Diagnosis and Treatment of Atopic Dermatitis and Psoriasis

Psoriasis and atopic dermatitis fall within the category of cutaneous immune-mediated inflammatory diseases (IMIDs). The prevalence of IMIDs is increasing in industrialized societies, influenced by both environmental changes and a genetic predisposition. However, the exact immune factors driving these chronic, progressive diseases are not fully understood. By using multi-omics techniques in cutaneous IMIDs, it is expected to advance the understanding of skin biology, uncover the underlying mechanisms of skin conditions, and potentially devise precise and personalized approaches to diagnosis and treatment. We provide a narrative review of the current knowledge in genomics, epigenomics, and proteomics of atopic dermatitis and psoriasis. A literature search was performed for articles published until 30 November 2023. Although there is still much to uncover, recent evidence has already provided valuable insights, such as proteomic profiles that permit differentiating psoriasis from mycosis fungoides and β-defensin 2 correlation to PASI and its drop due to secukinumab first injection, among others.

Challenges and promise of targeting miRNA in rheumatic diseases: a computational approach to identify miRNA association with cell types, cytokines, and disease mechanisms

MicroRNAs (miRNAs) are small non-coding RNAs that alter the expression of target genes at the post-transcriptional level, influencing diverse outcomes in metabolism, cell differentiation, proliferation, cell survival, and cell death. Dysregulated miRNA expression is implicated in various rheumatic conditions, including ankylosing spondylitis (AS), gout, juvenile idiopathic arthritis (JIA), osteoarthritis (OA), psoriatic arthritis, rheumatoid arthritis (RA), Sjogren's syndrome, systemic lupus erythematosus (SLE) and systemic sclerosis. For this review, we used an open-source programming language- PowerShell, to scan the massive number of existing primary research publications on PubMed on miRNAs in these nine diseases to identify and count unique co-occurrences of individual miRNAs and the disease name. These counts were used to rank the top seven most relevant immuno-miRs based on their research volume in each rheumatic disease. Individual miRNAs were also screened for publication with the names of immune cells, cytokines, and pathological processes involved in rheumatic diseases. These occurrences were tabulated into matrices to identify hotspots for research relevance. Based on this information, we summarize the basic and clinical findings for the top three miRNAs - miR-146, miR-155, and miR-21 - whose relevance spans across multiple rheumatic diseases. Furthermore, we highlight some unique miRNAs for each disease and why some rheumatic conditions lack research in this emerging epigenetics field. With the overwhelming number of publications on miRNAs in rheumatic diseases, this review serves as a 'relevance finder' to guide researchers in selecting miRNAs based on the compiled existing knowledge of their involvement in disease pathogenesis. This approach applies to other disease contexts with the end goal of developing miRNA-based therapeutics.

Profiling salivary miRNA expression levels in Fanconi anemia patients - a pilot study

The overarching goal of this study is to predict the risk of developing oral squamous cell carcinoma (OSCC) in Fanconi anemia (FA) patients. We have compared the microRNA (miRNA, miR) expression levels in saliva samples from FA patients (n = 50) who are at a low-moderate and/or high risk of developing OSCC to saliva samples from healthy controls (n = 16). The miRNA expression levels in saliva samples were quantified using qPCR. We observed that miR-744, miR-150-5P, and miR-146B-5P had the best discriminatory capacity between FA patients and controls, with an area under the curve (AUC) of 94.0%, 92.9% and 85.3%, respectively. Our data suggest that miR-1, miR-146B-5P, miR-150-5P, miR-155-5P, and miR-744 could be used as panel to predict the risk of developing OSCC in FA patients, with a 89.3% sensitivity and a 68.2% specificity (AUC = 81.5%). Our preliminary data support the notion that the expression levels of salivary miRNAs have the potential to predict the risk of developing OSCC in FA patients and in the future may reduce deaths associated with OSCC.

Hypoxia-inducible microRNA-155 negatively regulates epithelial barrier in eosinophilic esophagitis by suppressing tight junction claudin-7

MicroRNA (miRNA)-mediated mRNA regulation directs many homeostatic and pathological processes, but how miRNAs coordinate aberrant esophageal inflammation during eosinophilic esophagitis (EoE) is poorly understood. Here, we report a deregulatory axis where microRNA-155 (miR-155) regulates epithelial barrier dysfunction by selectively constraining tight junction CLDN7 (claudin-7). MiR-155 is elevated in the esophageal epithelium of biopsies from patients with active EoE and in cell culture models. MiR-155 localization using in situ hybridization (ISH) in patient biopsies and intra-epithelial compartmentalization of miR-155 show expression predominantly within the basal epithelia. Epithelial miR-155 activity was evident through diminished target gene expression in 3D organotypic cultures, particularly in relatively undifferentiated basal cell states. Mechanistically, generation of a novel cell line with enhanced epithelial miR-155 stable overexpression induced a functionally deficient epithelial barrier in 3D air-liquid interface epithelial cultures measured by transepithelial electrical resistance (TEER). Histological assessment of 3D esophageal organoid cultures overexpressing miR-155 showed notable dilated intra-epithelial spaces. Unbiased RNA-sequencing analysis and immunofluorescence determined a defect in epithelial barrier tight junctions and revealed a selective reduction in the expression of critical esophageal tight junction molecule, claudin-7. Together, our data reveal a previously unappreciated role for miR-155 in mediating epithelial barrier dysfunction in esophageal inflammation.

Identification of potential miR‑155 target genes in epidermal immune microenvironment of atopic dermatitis patients and their inflammatory effects on HaCaT cells

Atopic dermatitis (AD) is a common inflammatory skin condition and the leading cause of morbidity associated with skin conditions worldwide. For the majority of patients, AD is a lifelong disease that cannot be cured completely. Therefore, in the present study, differentially expressed genes (DEGs) in the epidermal immune microenvironment were screened using bioinformatic techniques. Subsequently, an in vitro cellular model was constructed to investigate the role of microRNA (miR)-155 in immune infiltration during AD. In the present study, two datasets (GSE121212 and GSE157194) were downloaded from Gene Expression Omnibus, before the DEGs were screened and subjected to Gene Ontology and Kyoto Encyclopedia of Genes and Genomes functional enrichment analyses. miRNet was used to predict the possible target genes of miR-155 among the differentially expressed genes found. Consequently, peptidase inhibitor 3 (PI3), FOS-like 1, AP-1 transcription factor subunit (FOSL1), C-X-C motif chemokine ligand (CXCL)1 and CXCL8 were selected to be the potential target genes of miR-155 in the epidermal immune microenvironment of patients with AD. Concurrently, an inflammatory cell model using HaCaT cells was constructed by TNF-α and IFN-γ treatment. The effects of miR-155 on HaCaT cell proliferation and secretion of IL-1β, IL-6, IL-10, IL-15, PI3, FOSL1, CXCL1 and CXCL8 under inflammatory and non-inflammatory conditions were then analyzed. The results showed that after the HaCaT cells were transfected with miR-155, miR-155 inhibited HaCaT cell proliferation and decreased the mRNA expression levels of PI3 and CXCL8, increased the mRNA levels of FOSL1 and secretion levels of IL-1β, IL-6, IL-15 and CXCL1. By contrast, miR-155 decreased the secretion levels of IL-10 and CXCL8. In the inflammatory cell model of HaCaT cells, miR-155 was found to significantly inhibit the proliferation of HaCaT cells during inflammation whilst significantly increasing the secretion of IL-1β, IL-6, IL-10 and IL-15. In addition, miR-155 increased the mRNA expression and secretion levels of CXCL1 and CXCL8, whilst also increasing the mRNA expression levels of PI3. Results from the current study suggest that miR-155 can stimulate keratinocytes to produce inflammatory cytokines and proteins to enhance the inflammatory response in AD.

The role of microRNA in psoriasis: A review

Psoriasis is a chronic immune-mediated inflammatory skin disease that involves a complex interplay between infiltrated immune cells and keratinocytes. Great progress has been made in the research on the molecular mechanism of coding and non-coding genes, which has helped in clinical treatment. However, our understanding of this complex disease is far from clear. MicroRNAs (miRNAs) are small non-coding RNA molecules that are involved in post-transcriptional regulation, characterised by their role in mediating gene silencing. Recent studies on miRNAs have revealed their important role in the pathogenesis of psoriasis. We reviewed the current advances in the study of miRNAs in psoriasis; the existing research has found that dysregulated miRNAs in psoriasis notably affect keratinocyte proliferation and/or differentiation processes, as well as inflammation progress. In addition, miRNAs also influence the function of immune cells in psoriasis, including CD4+ T cells, dendritic cells, Langerhans cells and so on. In addition, we discuss possible miRNA-based therapy for psoriasis, such as the topical delivery of exogenous miRNAs, miRNA antagonists and miRNA mimics. Our review highlights the potential role of miRNAs in the pathogenesis of psoriasis, and we expect more research progress with miRNAs in the future, which will help us understand this complex skin disease more accurately.

The Interaction between the Host Genome, Epigenome, and the Gut-Skin Axis Microbiome in Atopic Dermatitis

Atopic dermatitis (AD) is a chronic inflammatory skin disease that occurs in genetically predisposed individuals. It involves complex interactions among the host immune system, environmental factors (such as skin barrier dysfunction), and microbial dysbiosis. Genome-wide association studies (GWAS) have identified AD risk alleles; however, the associated environmental factors remain largely unknown. Recent evidence suggests that altered microbiota composition (dysbiosis) in the skin and gut may contribute to the pathogenesis of AD. Examples of environmental factors that contribute to skin barrier dysfunction and microbial dysbiosis in AD include allergens, irritants, pollution, and microbial exposure. Studies have reported alterations in the gut microbiome structure in patients with AD compared to control subjects, characterized by increased abundance of Clostridium difficile and decreased abundance of short-chain fatty acid (SCFA)-producing bacteria such as Bifidobacterium. SCFAs play a critical role in maintaining host health, and reduced SCFA production may lead to intestinal inflammation in AD patients. The specific mechanisms through which dysbiotic bacteria and their metabolites interact with the host genome and epigenome to cause autoimmunity in AD are still unknown. By understanding the combination of environmental factors, such as gut microbiota, the genetic and epigenetic determinants that are associated with the development of autoantibodies may help unravel the pathophysiology of the disease. This review aims to elucidate the interactions between the immune system, susceptibility genes, epigenetic factors, and the gut microbiome in the development of AD.

Atopic Dermatitis Across Shades of Skin

Atopic dermatitis (AD) is a chronic, heterogeneous inflammatory skin disease that is associated with immense patient burden globally. There is increasing appreciation of disparities among patients identified as having skin of color (SOC), which often refers to patients of non-White race or non-European ancestry, but can broadly include individuals from a number of different racial, ethnic, ancestral, and skin pigmentation groups based on definition. In this narrative review, we discuss key terminology as it relates to AD across shades of skin, including modern definitions of 'race', 'ethnicity', and 'SOC'. We then synthesize the current literature describing disparities in AD prevalence, disease recognition, and burden alongside current data regarding genetic and immunologic findings across SOC populations. In the context of these findings, we highlight key concomitant social determinants of health, including environmental factors, socioeconomic status, and access to care, for which race often serves as a proxy for true biological and genetic differences. Finally, we discuss future efforts to shift to a more inclusive understanding of AD to encompass all shades of skin, to ensure equitable representation of diverse populations in high impact research, and intensify efforts to address the critical upstream factors driving observed disparities.

Critical role of epigenetic modification in the pathogenesis of atopic dermatitis

Atopic dermatitis is a chronic inflammatory skin disease characterised by recurrent eczema-like lesions and severe pruritus, along with drying and decrustation of skin. Current research relates the pathogenesis of atopic dermatitis mainly to genetic susceptibility, abnormal skin barrier function, immune disorders, Staphylococcus aureus colonisation, microbiological dysfunction and vitamin D insufficiency. Epigenetic modifications are distinct genetic phenotypes resulting from environment-driven changes in chromosome functions in the absence of nuclear DNA sequence variation. Classic epigenetic events include DNA methylation, histone protein modifications and non-coding RNA regulation. Increasing evidence has indicated that epigenetic events are involved in the pathogenesis of atopic dermatitis by their effects on multiple signalling pathways which in turn influence the above factors. This review primarily analyses the function of epigenetic regulation in the pathogenesis of atopic dermatitis. In addition, it tries to make recommendations for personalised epigenetic treatment strategies for atopic dermatitis in the future.

In chronic spontaneous urticaria, IgE and C-reactive protein are linked to distinct microRNAs and interleukin-31

BACKGROUND

Chronic spontaneous urticaria (CSU) is a common and disabling disease. Assessments of IgE and C-reactive protein (CRP) are recommended in the diagnostic work-up, but the role and clinical relevance of these biomarkers are not well characterized. Moreover, it remains unknown if elevated levels of IgE or CRP are linked to CSU microRNA (miRNA) signatures or interleukin 31 (IL-31).

METHODS

We measured IgE and CRP serum levels in 47 CSU patients (and 45 healthy controls) and determined CSU disease activity using the urticaria activity score (UAS7). Expression levels of miR-155 and miR-221 were assessed by RT-PCR, and IL-31 levels were determined by ELISA.

RESULTS

Total IgE and CRP levels were independently increased in CSU patients. IgE and CRP levels were highest and lowest in patients with high and mild disease activity. IgE levels correlated with miR-155 levels, whereas CRP levels correlated with miR-221 levels. miR-155 and miR-221 were significantly overexpressed in CSU patients. ROC analyses linked miRNA-155 and CSU with a sensitivity of 79% and specificity of 87%, and miRNA-221 and CSU with a sensitivity of 75% and specificity of 91%. High CRP and miR-221 expression levels were linked to elevated levels of IgG anti-TPO and IL-31.

CONCLUSION

IgE and CRP are useful biomarkers for disease activity in CSU, with distinct miRNA profiles. High CRP and miR-221 levels may point to autoimmune CSU and a role for IL-31.

Sp1-mediated miR-193b suppresses atopic dermatitis by regulating HMGB1

Atopic dermatitis (AD) is a chronic and recurrent inflammatory skin disease. Keratinocyte dysfunction plays a central role in AD development. MicroRNA is a novel player in many inflammatory and immune skin diseases. In this study, we investigated the potential function and regulatory mechanism of miR-193b in AD. Inflamed human keratinocytes (HaCaT) were established by tumor necrosis factor (TNF)-α/interferon (IFN)-γ stimulation. Cell viability was measured using MTT assay, while the cell cycle was analyzed using flow cytometry. The cytokine levels were examined by enzyme-linked immunosorbent assay. The interaction between Sp1, miR-193b, and HMGB1 was analyzed using dual luciferase reporter and/or chromatin immunoprecipitation (ChIP) assays. Our results revealed that miR-193b upregulation enhanced the proliferation of TNF-α/IFN-γ-treated keratinocytes and repressed inflammatory injury. miR-193b negatively regulated high mobility group box 1 (HMGB1) expression by directly targeting HMGB1. Furthermore, HMGB1 knockdown promoted keratinocyte proliferation and inhibited inflammatory injury by repressing nuclear factor kappa-B (NF-κB) activation. During AD progression, HMGB1 overexpression abrogated increase of keratinocyte proliferation and repression of inflammatory injury caused by miR-193b overexpression. Moreover, transcription factor Sp1 was identified as the biological partner of the miR-193b promoter in promoting miR-193b expression. Therefore, Sp1 upregulation promotes keratinocyte proliferation and represses inflammatory injury during AD development via promoting miR-193b expression and repressing HMGB1/NF-κB activation.

Genomic, Epigenomic, Transcriptomic, Proteomic and Metabolomic Approaches in Atopic Dermatitis

Atopic dermatitis (AD) is a chronic inflammatory skin disease with a high prevalence in the developed countries. It is associated with atopic and non-atopic diseases, and its close correlation with atopic comorbidities has been genetically demonstrated. One of the main roles of genetic studies is to comprehend the defects of the cutaneous barrier due to filaggrin deficit and epidermal spongiosis. Recently, epigenetic studies started to analyze the influence of the environmental factors on gene expression. The epigenome is considered to be a superior second code that controls the genome, which includes alterations of the chromatin. The epigenetic changes do not alter the genetic code, however, changes in the chromatin structure could activate or inhibit the transcription process of certain genes and consequently, the translation process of the new mRNA into a polypeptide chain. In-depth analysis of the transcriptomic, metabolomic and proteomic studies allow to unravel detailed mechanisms that cause AD. The extracellular space and lipid metabolism are associated with AD that is independent of the filaggrin expression. On the other hand, around 45 proteins are considered as the principal components in the atopic skin. Moreover, genetic studies based on the disrupted cutaneous barrier can lead to the development of new treatments targeting the cutaneous barrier or cutaneous inflammation. Unfortunately, at present, there are no target therapies that focus on the epigenetic process of AD. However, in the future, miR-143 could be an important objective for new therapies, as it targets the miR-335:SOX axis, thereby restoring the miR-335 expression, and repairing the cutaneous barrier defects.

Intrinsic Effects of Exposome in Atopic Dermatitis: Genomics, Epigenomics and Regulatory Layers

Atopic dermatitis (AD) or atopic eczema is an increasingly manifested inflammatory skin disorder of complex etiology which is modulated by both extrinsic and intrinsic factors. The exposome includes a person's lifetime exposures and their effects. We recently reviewed the extrinsic exposome's environmental risk factors that contribute to AD. The periods of pregnancy, infancy, and teenage years are recognized as crucial stages in the formation of AD, where the exposome leads to enduring impacts on the immune system. However, research is now focusing on the interactions between intrinsic pathways that are modulated by the extrinsic exposome, including genetic variation, epigenetic modifications, and signals, such as diet, stress, and microbiome interactions. As a result, immune dysregulation, barrier dysfunction, hormonal fluctuations, and skin microbiome dysbiosis are important factors contributing to AD development, and their in-depth understanding is crucial not only for AD treatment but also for similar inflammatory disorders.

The Essential Role of microRNAs in Inflammatory and Autoimmune Skin Diseases-A Review

The etiopathogenesis of autoimmune skin diseases is complex and still not fully understood. The role of epigenetic factors is emphasized in the development of such diseases. MicroRNAs (miRNAs), a group of non-coding RNAs (ncRNAs-non-coding RNAs), are one of the important post-transcriptional epigenetic factors. miRNAs have a significant role in the regulation of the immune response by participating in the process of the differentiation and activation of B and T lymphocytes, macrophages, and dendritic cells. Recent advances in research on epigenetic factors have provided new insights into the pathogenesis and potential diagnostic and therapeutic targets of many pathologies. Numerous studies revealed a change in the expression of some microRNAs in inflammatory skin disorders, and the regulation of miRNA expression is a promising therapeutic goal. This review presents the state of the art regarding changes in the expression and role of miRNAs in inflammatory and autoimmune skin diseases, including psoriasis, atopic dermatitis, vitiligo, lichen planus, hidradenitis suppurativa, and autoimmune blistering diseases.

CTLA4 mRNA is downregulated by miR-155 in regulatory T cells, and reduced blood CTLA4 levels are associated with poor prognosis in metastatic melanoma patients

Cytotoxic T lymphocyte-associated antigen-4 (CTLA-4) is an immune checkpoint expressed in regulatory T (Treg) cells and activated T lymphocytes. Despite its potential as a treatment strategy for melanoma, CTLA-4 inhibition has limited efficacy. Using data from The Cancer Genome Atlas (TCGA) melanoma database and another dataset, we found that decreased CTLA4 mRNA was associated with a poorer prognosis in metastatic melanoma. To investigate further, we measured blood CTLA4 mRNA in 273 whole-blood samples from an Australian cohort and found that it was lower in metastatic melanoma than in healthy controls and associated with worse patient survival. We confirmed these findings using Cox proportional hazards model analysis and another cohort from the US. Fractionated blood analysis revealed that Treg cells were responsible for the downregulated CTLA4 in metastatic melanoma patients, which was confirmed by further analysis of published data showing downregulated CTLA-4 surface protein expression in Treg cells of metastatic melanoma compared to healthy donors. Mechanistically, we found that secretomes from human metastatic melanoma cells downregulate CTLA4 mRNA at the post-transcriptional level through miR-155 while upregulating FOXP3 expression in human Treg cells. Functionally, we demonstrated that CTLA4 expression inhibits the proliferation and suppressive function of human Treg cells. Finally, miR-155 was found to be upregulated in Treg cells from metastatic melanoma patients compared to healthy donors. Our study provides new insights into the underlying mechanisms of reduced CTLA4 expression observed in melanoma patients, demonstrating that post-transcriptional silencing of CTLA4 by miRNA-155 in Treg cells may play a critical role. Since CTLA-4 expression is downregulated in non-responder melanoma patients to anti-PD-1 immunotherapy, targeting miRNA-155 or other factors involved in regulating CTLA4 expression in Treg cells without affecting T cells could be a potential strategy to improve the efficacy of immunotherapy in melanoma. Further research is needed to understand the molecular mechanisms regulating CTLA4 expression in Treg cells and identify potential therapeutic targets for enhancing immune-based therapies.

miRNA implication in the pathogenesis and the outcome of Tunisian endemic pemphigus foliaceous

Pemphigus foliaceous (PF) is a bullous autoimmune skin disease diagnosed through sera and skin analyses. PF severity is associated with maintained anti-Dsg1 sera levels and its prognosis is unpredictable. MicroRNA (miRNA), dynamic regulators of immune function, have been identified as potential biomarkers for some autoimmune diseases. This study aimed to assess the miRNA expression of miR-17-5p, miR-21-5p, miR-146a-5p, miR-155-5p and miR-338-3p using quantitative real-time PCR in peripheral blood mononuclear cells (PBMC) and lesional skin samples from untreated and treated PF patients (both remittent and chronic) over 3 months. Overall, miRNA expression was significantly higher in PBMC than in biopsy samples. Blood miR-21 expression was increased in untreated patients compared to controls and had a diagnostic value with an AUC of 0.78. After 6 weeks, it decreased significantly, similar to anti-Dsg1 antibodies and the PDAI score. In addition, a positive correlation was observed between cutaneous miR-21 expression and the disease activity score. Conversely, cutaneous expressions of miR-17, miR-146a and miR-155 were significantly higher in treated chronic patients compared to remittent ones. The cutaneous level of miR-155 positively correlated with pemphigus activity, making it a potential predictive marker for patients' clinical stratification with an AUC of 0.86.These findings suggest that blood miR-21 and cutaneous miR-155 can be used as supplemental markers for PF diagnosis and activity, respectively in addition to classical parameters.

miRNAs' Cross-Involvement in Skin Allergies: A New Horizon for the Pathogenesis, Diagnosis and Therapy of Atopic Dermatitis, Allergic Contact Dermatitis and Chronic Spontaneous Urticaria

Skin inflammation is a common underlying feature of atopic dermatitis, allergic contact dermatitis and chronic spontaneous urticaria. The pathogenetic mechanisms have not been fully elucidated. The purpose of this study was to examine whether miRNA, by regulating inflammatory mechanisms through the modulation of innate and adaptive immune responses, could play a major role in the pathogenesis of these skin conditions. We conducted a narrative review using the Pubmed and Embase scientific databases and search engines to find the most relevant miRNAs related to the pathophysiology, severity and prognosis of skin conditions. The studies show that miRNAs are involved in the pathogenesis and regulation of atopic dermatitis and can reveal an atopic predisposition or indicate disease severity. In chronic spontaneous urticaria, different miRNAs which are over-expressed during urticaria exacerbations not only play a role in the possible response to therapy or remission, but also serve as a marker of chronic autoimmune urticaria and indicate associations with other autoimmune diseases. In allergic contact dermatitis, miRNAs are upregulated in inflammatory lesions and expressed during the sensitization phase of allergic response. Several miRNAs have been identified as potential biomarkers of these chronic skin conditions, but they are also possible therapeutic targets.

Assessment of Spatial and Temporal Variation in the Skin Transcriptome of Atopic Dermatitis by Use of 1.5 mm Minipunch Biopsies

Atopic dermatitis (AD) is a common inflammatory skin disorder characterized by a heterogeneous and fluctuating disease course. To obtain a detailed molecular understanding of both the temporal and spatial variation in AD, we conducted a longitudinal case-control study, in which we followed a population, the GENAD (Gentofte AD) cohort, of mild-to-moderate patients with AD and matched healthy controls for more than a year. By the use of 1.5 mm minipunch biopsies, we obtained 393 samples from lesional, nonlesional, and healthy skin from multiple anatomical regions at different time points for transcriptomic profiling. We observed that the skin transcriptome was remarkably stable over time, with the largest variation being because of disease, individual, and skin site. Numerous AD-specific, differentially expressed genes were identified and indicated a disrupted skin barrier and activated immune response as the main features of AD. We also identified potentially novel targets in AD, including IL-37, MAML1, and several long noncoding RNAs. We envisage that the application of small biopsies, such as those introduced in this study, combined with omics technologies, will enable future skin research, in which multiple sampling from the same individual will give a more detailed, dynamic picture of how a disease fluctuates in time and space.

Circulating microRNA as Biomarkers for Gestational Diabetes Mellitus-A Systematic Review and Meta-Analysis

Gestational diabetes mellitus (GDM) is a severe pregnancy complication for both the woman and the child. Women who suffer from GDM have a greater risk of developing Type 2 diabetes mellitus (T2DM) later in life. Identification of any potential biomarkers for the early prediction of gestational diabetes can help prevent the disease in women with a high risk. Studies show microRNA (miRNA) as a potential biomarker for the early discovery of GDM, but there is a lack of clarity as to which miRNAs are consistently altered in GDM. This study aimed to perform a systematic review and meta-analysis to investigate miRNAs associated with GDM by comparing GDM cases with normoglycemic controls. The systematic review was performed according to PRISMA guidelines with searches in PubMed, Web of Science, and ScienceDirect. The primary search resulted in a total of 849 articles, which were screened according to the prior established inclusion and exclusion criteria. Following the screening of articles, the review was based on the inclusion of 35 full-text articles, which were evaluated for risk of bias and estimates of quality, after which data were extracted and relative values for miRNAs were calculated. A meta-analysis was performed for the miRNA species investigated in three or more studies: MiR-29a, miR-330, miR-134, miR-132, miR-16, miR-223, miR-155, miR-122, miR-17, miR-103, miR-125, miR-210, and miR-222. While some miRNAs showed considerable between-study variability, miR-29a, miR-330, miR-134, miR-16, miR-223, and miR-17 showed significant overall upregulation in GDM, while circulating levels of miR-132 and miR-155 were decreased among GDM patients, suggesting further studies of these as biomarkers for early GDM discovery.

The role of ubiquitin pathway-mediated regulation of immune checkpoints in cancer immunotherapy

With the continuous cognition of the relationship between tumor cells and tumor immune microenvironment, immunotherapy based on the immune checkpoint blockade has achieved great breakthroughs, led to improved clinical outcomes, and prolonged survival for cancer patients in recent years. Nevertheless, the de novo or acquired resistance to immunotherapy has greatly counteracted the efficacy, leading to a 20%-40% overall response rate. Thus, further in-depth understanding of the regulation of the tumor microenvironment and antitumor immunity is urgently warranted. Ubiquitination-mediated protein degradation plays vital roles in protein stabilization, activation, and dynamics as well as in cellular homeostasis modulation. The dysregulated ubiquitination and deubiquitination are closely related to the changes in physiological and pathological processes, which subsequently result in a variety of diseases including cancer. In this review, the authors first summarize the current knowledge about the involvement of the ubiquitin-proteasome system in tumor development with the ubiquitin conjugation-regulated stability of p53, phosphatase and tensin homolog, and Myc protein as examples, then dissect the potential implications of ubiquitination-mediated immune checkpoints degradation in tumor microenvironment and immune responses, and finally discuss the effects of therapeutically targeting the ubiquitin-proteasome pathway on immunotherapy, with the goal of providing deep insights into the exploitation of more precise and effective combinational therapy against cancer.

Blood-Based Biomarkers for Eosinophilic Esophagitis and Concomitant Atopic Diseases: A Look into the Potential of Extracellular Vesicles

Eosinophilic esophagitis (EoE) is a chronic, Th2-inflammatory disease of the esophagus that can severely affect food intake. Currently, diagnosis and assessing response to treatment of EoE is highly invasive and requires endoscopy with esophageal biopsies. Finding non-invasive and accurate biomarkers is important for improving patient well-being. Unfortunately, EoE is usually accompanied by other atopies, which make it difficult to identify specific biomarkers. Providing an update of circulating EoE biomarkers and concomitant atopies is therefore timely. This review summarizes the current knowledge in EoE blood biomarkers and two of its most common comorbidities, bronchial asthma (BA) and atopic dermatitis (AD), focusing on dysregulated proteins, metabolites, and RNAs. It also revises the current knowledge on extracellular vesicles (EVs) as non-invasive biomarkers for BA and AD, and concludes with the potential use of EVs as biomarkers in EoE.

A blockade of microRNA-155 signal pathway has a beneficial effect on neural injury after intracerebral haemorrhage via reduction in neuroinflammation and oxidative stress

MicroRNAs (miRNAs) have important contributions to multiple pathophysiological processes for cellular response to stress and are considered as promising therapeutic targets with respect to drug development due to their small size, relative ease of delivery, and sequence specificity. Thus, in the current report, we examined the effects of inhibiting miRNA-155 (miR-155) on the levels of pro-inflammatory cytokines (PICs), oxidative stress products as well as vascular endothelial growth factor (VEGF) in the parietal cortex and hippocampus of rats following intracerebral haemorrhage (ICH). Real time PCR was used to examine the levels of miR-155 in the parietal cortex and hippocampus of rats; and ELISA to measure IL-1β, IL-6 and TNF-α, oxidative 8-iso PGF2α and 8-OHdG, and VEGF. Additionally, modified neurological Severity Score (mNSS) was examined to indicate neurological function in animals. In results, with induction of ICH, the levels of miR-155 were amplified in the parietal cortex and hippocampus and this was accompanied with increases of IL-1β, IL-6 and TNF-α; and 8-iso PGF2α and 8-OHdG. Intracerebroventricular infusion of miR-155 inhibitor attenuated the elevation of PICs and amplification of oxidative stress products. Interestingly, miR-155 inhibitor promoted VEGF levels. Furthermore, inhibition of miR-155 led to improvement of neurological deficits in ICH rats. In conclusion, miR-155 signal in the parietal cortex and hippocampus is engaged in the processes of neural injury during ICH and blocking central miR-155 pathway plays a beneficial role in regulating neurological function via reduction in PICs and products of oxidative stress; and enhancement of VEGF. This has implications to target miR-155 and its downstream signal pathway for neuronal dysfunction and vulnerability related to ICH.

miR-aculous new avenues for cancer immunotherapy

The rising toll of cancer globally necessitates ingenuity in early detection and therapy. In the last decade, the utilization of immune signatures and immune-based therapies has made significant progress in the clinic; however, clinical standards leave many current and future patients without options. Non-coding RNAs, specifically microRNAs, have been explored in pre-clinical contexts with tremendous success. MicroRNAs play indispensable roles in programming the interactions between immune and cancer cells, many of which are current or potential immunotherapy targets. MicroRNAs mechanistically control a network of target genes that can alter immune and cancer cell biology. These insights provide us with opportunities and tools that may complement and improve immunotherapies. In this review, we discuss immune and cancer cell-derived miRNAs that regulate cancer immunity and examine miRNAs as an integral part of cancer diagnosis, classification, and therapy.

Anti-Inflammatory microRNAs for Treating Inflammatory Skin Diseases

Skin inflammation occurs due to immune dysregulation because of internal disorders, infections, and allergic reactions. The inflammation of the skin is a major sign of chronic autoimmune inflammatory diseases, such as psoriasis, atopic dermatitis (AD), and lupus erythematosus. Although there are many therapies for treating these cutaneous inflammation diseases, their recurrence rates are high due to incomplete resolution. MicroRNA (miRNA) plays a critical role in skin inflammation by regulating the expression of protein-coding genes at the posttranscriptional level during pathogenesis and homeostasis maintenance. Some miRNAs possess anti-inflammatory features, which are beneficial for mitigating the inflammatory response. miRNAs that are reduced in inflammatory skin diseases can be supplied transiently using miRNA mimics and agomir. miRNA-based therapies that can target multiple genes in a given pathway are potential candidates for the treatment of skin inflammation. This review article offers an overview of the function of miRNA in skin inflammation regulation, with a focus on psoriasis, AD, and cutaneous wounds. Some bioactive molecules can target and modulate miRNAs to achieve the objective of inflammation suppression. This review also reports the anti-inflammatory efficacy of these molecules through modulating miRNA expression. The main limitations of miRNA-based therapies are rapid biodegradation and poor skin and cell penetration. Consideration was given to improving these drawbacks using the approaches of cell-penetrating peptides (CPPs), nanocarriers, exosomes, and low-frequency ultrasound. A formulation design for successful miRNA delivery into skin and target cells is also described in this review. The possible use of miRNAs as biomarkers and therapeutic modalities could open a novel opportunity for the diagnosis and treatment of inflammation-associated skin diseases.

Identification and characterization of novel CD274 (PD-L1) regulating microRNAs and their functional relevance in melanoma

BACKGROUND

Immune checkpoint inhibitors directed against programmed cell death 1 (PDCD1/PD1) receptor and programmed cell death-ligand 1 (CD274/PD-L1) have been recently successfully implemented for the treatment of many cancers, but the response rate of tumour patients is still limited due to intrinsic and acquired resistances. However, the underlying molecular mechanisms of this limited response have still to be defined in detail. The aim of this study is to uncover processes inhibiting PDCD1/CD274 expression thereby enhancing anti-tumour immune responses. The identification and characterization of microRNAs (miRNAs) targeting the 3'-untranslated region (3'-UTR) as well as the coding sequence (CDS) of CD274 will provide the basis for a new drug development.

METHODS

Human melanoma cell lines and tissue samples were subjected to mRNA and/or protein expression analysis using qPCR, Western blot, flow cytometry, and/or immunohistochemistry. The data were correlated to clinical parameters. MiRNA trapping by RNA in vitro affinity purification (miTRAP) technology in combination with small RNA sequencing and different bioinformatics tools were employed to identify CD274-regulating miRNAs.

RESULTS

Screening based on miTRAP in combination with RNAseq identified a large number of novel CD274-regulating candidate miRNAs, from which eight selected miRNAs were functionally validated. Five out of eight miRNAs were able to significantly reduce CD274 surface expression indicating that these miRNAs directly bind to the 3'-UTR or CDS of the CD274 gene. The miRNA-mediated inhibition of CD274 expression was accompanied by an increased T cell recognition. Furthermore, an inverse expression of three CD274-regulating miRNAs and CD274 was demonstrated in melanoma lesions. A CD274 miRNA score was generated, which was associated with disease progression and reduced survival of melanoma patients.

CONCLUSIONS

These data revealed a novel mechanism that miRNAs targeting the CDS of immune checkpoint genes are functional, have prognostic relevance, and also the potential for the development of novel miRNA-based therapies.

IgG from Adult Atopic Dermatitis (AD) Patients Induces Thymic IL-22 Production and CLA Expression on CD4+ T Cells: Possible Epigenetic Implications Mediated by miRNA

Atopic dermatitis (AD) is a common relapsing inflammatory skin disorder characterized by immune-mediated inflammation and epidermal barrier dysfunction. The pathogenesis of AD is multifactorial and has not been fully elucidated to date. This study aimed to evaluate whether serum IgG from adult AD patients could modulate the thymic maturation of IL-22-producing T cells and CLA+ T cells of non-atopic infants. Given that miRNAs regulate immune response genes, we evaluated whether miRNA expression is also altered in cultured thymocytes. Thymocytes were cultured with purified IgG from AD patients or control conditions (mock, Intravenous-IgG (IVIg), non-atopic IgG, or atopic non-AD IgG). Using flow cytometry analysis, we assessed the expression of CLA and intracellular levels of IL-4, IFN-γ, and IL-22 on double-positive T cells (DP T), CD4 T cells, or CD8 T cells. We also investigated the frequency of IgG isotypes and their direct interaction with the thymic T cells membrane. The miRNA profiles were evaluated by the Illumina small RNA-seq approach. MiRNA target gene prediction and enrichment analyses were performed using bioinformatics. Increased frequencies of IL-22 and CLA+ producing CD4+ T cells cultured with IgG of AD patients was seen in non-atopic infant thymocytes compared to all control conditions. No alterations were observed in the frequency of IgG isotypes among evaluated IgG pools. Evidence for a direct interaction between IgG and thymic DP T, CD4 T, and CD8 T cells is presented. The small RNA-seq analysis identified ten mature miRNAs that were modulated by AD IgG compared to mock condition (miR-181b-5p, hsa-miR-130b-3p, hsa-miR-26a-5p, hsa-miR-4497, has-miR-146a, hsa-let-7i-5p, hsa-miR-342-3p, has-miR-148a-3p, has-miR-92a and has-miR-4492). The prediction of the targetome of the seven dysregulated miRNAs between AD and mock control revealed 122 putative targets, and functional and pathway enrichment analyses were performed. Our results enhance our understanding of the mechanism by which IgG can collaborate in thymic T cells in the setting of infant AD.

Differentially Expressed miRNAs in Ulcerative Colitis and Crohn’s Disease

Differential microRNA (miRNA or miR) regulation is linked to the development and progress of many diseases, including inflammatory bowel disease (IBD). It is well-established that miRNAs are involved in the differentiation, maturation, and functional control of immune cells. miRNAs modulate inflammatory cascades and affect the extracellular matrix, tight junctions, cellular hemostasis, and microbiota. This review summarizes current knowledge of differentially expressed miRNAs in mucosal tissues and peripheral blood of patients with ulcerative colitis and Crohn’s disease. We combined comprehensive literature curation with computational meta-analysis of publicly available high-throughput datasets to obtain a consensus set of miRNAs consistently differentially expressed in mucosal tissues. We further describe the role of the most relevant differentially expressed miRNAs in IBD, extract their potential targets involved in IBD, and highlight their diagnostic and therapeutic potential for future investigations.

IL-32 promotes the occurrence of atopic dermatitis by activating the JAK1/microRNA-155 axis

Background

This study aims to explore the mechanism of interleukin-32 (IL-32) affecting atopic dermatitis (AD) through the Janus-activated kinase-1 (JAK1)/microRNA-155 (miR-155) axis.

Methods

In this study, skin tissue samples and blood samples from normal subjects and patients with AD, human immortalized keratinocytes (HaCaT), and PA-induced mouse models of AD were selected for expression determination of IL-32, JAK1 and miR-155. The interaction among IL-32, JAK1 and miR-155 was identified with their roles in AD analyzed through loss- and gain-of-function assays.

Results

Elevated IL-32 was detected in AD tissues and blood samples and promoted the occurrence of AD. IL-32 upregulated JAK1 expression and phosphorylation of its downstream genes, thus activating the JAK signaling pathway. JAK1 promoted the expression of miR-155. IL-32/JAK1/miR-155 axis promoted inflammation in the AD skin reconstruction model. In vivo experiments further confirmed that IL-32 promoted AD development by activating the JAK1/miR-155 axis.

Conclusion

The present study underlined that IL-32 promoted the occurrence of AD by promoting JAK1 expression to upregulate miR-155 expression.

Supplementary Information

The online version contains supplementary material available at 10.1186/s12967-022-03375-x.

miR-582 Suppresses the Proliferation of B-Cell Precursor Acute Lymphoblastic Leukemia (BCP-ALL) Cells and Protects Them From Natural Killer Cell-Mediated Cytotoxicity

B-cell precursor acute lymphoblastic leukemia (BCP-ALL) is a malignancy characterized by the aberrant accumulation of immature B-cell precursors in bone marrow and other lymphoid organs. Although several intrinsic regulatory signals participating in BCP-ALL have been clarified, detailed intrinsic and extrinsic mechanisms that regulate BCP-ALL progression have not been fully understood. In the current study, we report that miR-582 is downregulated in BCP-ALL cells compared with normal B cells. Forced overexpression of miR-582 attenuated BCP-ALL cell proliferation and survival. We found that miR-582 overexpression disturbed the mitochondrial metabolism of BCP-ALL cells, leading to less ATP but more ROS production. Mechanistically, we identified PPTC7 as a direct target of miR-582. MiR-582 overexpression inhibited the activity of CoQ10, which is downstream of PPTC7 and played an important positive regulatory role in mitochondrial electron transportation. Finally, we found that overexpression of miR-582 upregulated the expression of immune checkpoint molecule CD276 and reduced NK cell-mediated cytotoxicity against BCP-ALL cells. CD276 blockade significantly increased NK cell-mediated cytotoxicity against miR-582-overexpressing BCP-ALL cells. Together, our research demonstrates that miR-582 acts as a negative regulator of BCP-ALL cells by reducing proliferation and survival, but protects BCP-ALL cells from NK cell-mediated cytotoxicity, suggesting that miR-582 may be a new therapeutic biomarker for BCP-ALL with CD276 blocker.

Role of Respiratory Epithelial Cells in Allergic Diseases

The airway epithelium provides the first line of defense to the surrounding environment. However, dysfunctions of this physical barrier are frequently observed in allergic diseases, which are tightly connected with pro- or anti-inflammatory processes. When the epithelial cells are confronted with allergens or pathogens, specific response mechanisms are set in motion, which in homeostasis, lead to the elimination of the invaders and leave permanent traces on the respiratory epithelium. However, allergens can also cause damage in the sensitized organism, which can be ascribed to the excessive immune reactions. The tight interaction of epithelial cells of the upper and lower airways with local and systemic immune cells can leave an imprint that may mirror the pathophysiology. The interaction with effector T cells, along with the macrophages, play an important role in this response, as reflected in the gene expression profiles (transcriptomes) of the epithelial cells, as well as in the secretory pattern (secretomes). Further, the storage of information from past exposures as memories within discrete cell types may allow a tissue to inform and fundamentally alter its future responses. Recently, several lines of evidence have highlighted the contributions from myeloid cells, lymphoid cells, stromal cells, mast cells, and epithelial cells to the emerging concepts of inflammatory memory and trained immunity.

miR-155 Is a Positive Regulator of FcεRI-Induced Cyclooxygenase-2 Expression and Cytokine Production in Mast Cells

MicroRNA-155 (miR-155) has been implicated in IgE-dependent allergic disease including asthma and atopic dermatitis. A few roles for miR-155 have been described in mast cells and some specifically related to IgE receptor signaling, but it is not completely understood. Here, we demonstrate by miRNA seq profiling and quantitative RT-PCR that miR-155 expression is significantly increased in human skin-derived mast cells (SMCs) and mouse bone marrow-derived mast cells (BMMCs) following FcεRI crosslinking with antigen. We demonstrate that FcεRI-induced expression of cyclooxygenase-2 (COX-2) was significantly inhibited in miR-155 knockout (KO) BMMCs whereas arachidonate-5-lipoxygenase (ALOX-5) expression and leukotriene C4 (LTC₄) biosynthesis, and degranulation were unaffected. FcεRI-induced cytokine production (TNF, IL-6, and IL-13) from miR-155 KO BMMCs was also significantly diminished. Correspondingly, Akt phosphorylation, but not protein expression, was inhibited in the absence of miR-155 whereas p38 and p42/44 were unaffected. Interesting, lipopolysaccharide (LPS)-induced cytokine production was increased in miR-155 KO BMMCs. Together, these data demonstrate that miR-155 specifically targets the FcεRI-induced prostaglandin and cytokine pathways, but not the leukotriene or degranulation pathways, in mast cells. The data further suggest that miR-155 acts indirectly by targeting a repressor of COX-2 expression and a phosphatase that normally blocks Akt phosphorylation. Overall, this study reveals the role of miR-155 as a positive regulator of mast cell function.

Aire suppresses CTLA-4 expression from the thymic stroma to control autoimmunity

Impaired production of thymic regulatory T cells (Tregs) is implicated in the development of Aire-dependent autoimmunity. Because Tregs require agonistic T cell receptor stimuli by self-antigens to develop, reduced expression of self-antigens from medullary thymic epithelial cells (mTECs) has been considered to play a major role in the reduced Treg production in Aire deficiency. Here, we show that mTECs abnormally express co-inhibitory receptor CTLA-4 if Aire is non-functional. Upon binding with CD80/CD86 ligands expressed on thymic dendritic cells (DCs), the ectopically expressed CTLA-4 from Aire-deficient mTECs removes the CD80/CD86 ligands from the DCs. This attenuates the ability of DCs to provide co-stimulatory signals and to present self-antigens transferred from mTECs, both of which are required for Treg production. Accordingly, impaired production of Tregs and organ-specific autoimmunity in Aire-deficient mice are rescued by the depletion of CTLA-4 expression from mTECs. Our studies illuminate the significance of mTEC-DC interaction coordinated by Aire for the establishment of thymic tolerance.

miRNA profiles change during grass pollen immunotherapy irrespective of clinical outcome

Background: Subcutaneous immunotherapy (SCIT) is widely used in the treatment of allergic rhinitis (AR). This study aimed to determine the expression of 48 miRNAs in patients with AR undergoing grass pollen SCIT and investigate relations with clinical outcomes. Methodology: Expression of selected miRNAs was determined using RT-PCR in the full blood of 16 patients with AR and seven healthy controls. Results: miR-136, miR-208 and miR-190 were upregulated in the AR group. After 6 months of SCIT, significant downregulation of some proinflammatory miRNAs and upregulation of several miRNAs regulating Th1/Th2 balance were found. No differences were found between good and poor responders. Conclusion: miRNAs may play a regulatory role in SCIT, leading to tolerance induction.

Co-Expression of miR155 or LSD1 shRNA Increases the Anti-Tumor Functions of CD19 CAR-T Cells

Chimeric antigen receptor (CAR) T cells targeting CD19 antigen have produced remarkable clinical outcomes for cancer patients. However, identifying measures to enhance effector function remains one of the most challenging issues in CD19-targeted immunotherapy. Here, we report a novel approach in which a microRNA (miRNA) or short-hairpin RNA (shRNA) cassette was integrated into CAR-expressing retroviral vectors. Using this system, we generated anti-CD19 CAR-T cells co-expressing miR155 or LSD1 shRNA and found that anti-CD19 CAR-T cells with miR155 upregulation or LSD1 downregulation exhibited increased anti-tumor functions in vitro and in vivo. Transcriptional profiling analysis by RNA sequencing revealed the targets of miR155 and LSD1 in anti-CD19 CAR-T cells. Our experiments indicated that introduction of miRNA or shRNA expression into anti-CD19 CAR T-cells might be an effective strategy to improve the anti-tumor effects of CAR-T cell therapy.

The Role of miRNA in Tumor Immune Escape and miRNA-Based Therapeutic Strategies

Tumor immune escape is a critical step in the malignant progression of tumors and one of the major barriers to immunotherapy, making immunotherapy the most promising therapeutic approach against tumors today. Tumor cells evade immune surveillance by altering the structure of their own, or by causing abnormal gene and protein expression, allowing for unrestricted development and invasion. These genetic or epigenetic changes have been linked to microRNAs (miRNAs), which are important determinants of post-transcriptional regulation. Tumor cells perform tumor immune escape by abnormally expressing related miRNAs, which reduce the killing effect of immune cells, disrupt the immune response, and disrupt apoptotic pathways. Consequently, there is a strong trend toward thoroughly investigating the role of miRNAs in tumor immune escape and utilizing them in tumor treatment. However, because of the properties of miRNAs, there is an urgent need for a safe, targeted and easily crossed biofilm vehicle to protect and deliver them in vivo, and exosomes, with their excellent biological properties, have successfully beaten traditional vehicles to provide strong support for miRNA therapy. This review summarizes the multiple roles of miRNAs in tumor immune escape and discusses their potential applications as an anti-tumor therapy. Also, this work proposes exosomes as a new opportunity for miRNA therapy, to provide novel ideas for the development of more effective tumor-fighting therapeutic approaches based on miRNAs.

Epigenetic regulation of pediatric and neonatal immune responses

Epigenetic regulation of transcription is a collective term that refers to mechanisms known to regulate gene transcription without changing the underlying DNA sequence. These mechanisms include DNA methylation and histone tail modifications which influence chromatin accessibility, and microRNAs that act through post-transcriptional gene silencing. Epigenetics is known to regulate a variety of biological processes, and the role of epigtenetics in immunity and immune-mediated diseases is becoming increasingly recognized. While DNA methylation is the most widely studied, each of these systems play an important role in the development and maintenance of appropriate immune responses. There is clear evidence that epigenetic mechanisms contribute to developmental stage-specific immune responses in a cell-specific manner. There is also mounting evidence that prenatal exposures alter epigenetic profiles and subsequent immune function in exposed offspring. Early life exposures that are associated with poor long-term health outcomes also appear to impact immune specific epigenetic patterning. Finally, each of these epigenetic mechanisms contribute to the pathogenesis of a wide variety of diseases that manifest during childhood. This review will discuss each of these areas in detail. IMPACT: Epigenetics, including DNA methylation, histone tail modifications, and microRNA expression, dictate immune cell phenotypes. Epigenetics influence immune development and subsequent immune health. Prenatal, perinatal, and postnatal exposures alter immune cell epigenetic profiles and subsequent immune function. Numerous pediatric-onset diseases have an epigenetic component. Several successful strategies for childhood diseases target epigenetic mechanisms.