Expression of miRNA-155, miRNA-223, miRNA-31, miRNA-21, miRNA-125b, and miRNA-146a in the Inflammatory Pathway of Hidradenitis Suppurativa

Biosensing circulating MicroRNAs in autoinflammatory skin diseases: Focus on Hidradenitis suppurativa

MicroRNAs (miRNAs) play a crucial role in the early diagnosis of autoinflammatory diseases, with Hidradenitis Suppurativa (HS) being a notable example. HS, an autoinflammatory skin disease affecting the pilosebaceous unit, profoundly impacts patients' quality of life. Its hidden nature, with insidious initial symptoms and patient reluctance to seek medical consultation, often leads to a diagnostic delay of up to 7 years. Recognizing the urgency for early diagnostic tools, recent research identified significant differences in circulating miRNA expression, including miR-24-1-5p, miR-146a-5p, miR26a-5p, miR-206, miR338-3p, and miR-338-5p, between HS patients and healthy controls. These miRNAs serve as potential biomarkers for earlier disease detection. Traditional molecular biology techniques, like reverse transcription quantitative-polymerase chain reaction (RT-qPCR), are employed for their detection using specific primers and probes. Alternatively, short peptides offer a versatile and effective means for capturing miRNAs, providing specificity, ease of synthesis, stability, and multiplexing potential. In this context, we present a computational simulation pipeline designed for crafting peptide sequences that can capture circulating miRNAs in the blood of patients with autoinflammatory skin diseases, including HS. This innovative approach aims to expedite early diagnosis and enhance therapeutic follow-up, addressing the critical need for timely intervention in HS and similar conditions.

Unraveling the Epigenetic Tapestry: Decoding the Impact of Epigenetic Modifications in Hidradenitis Suppurativa Pathogenesis

Hidradenitis suppurativa (HS) is a chronic autoinflammatory skin disorder, which typically occurs during puberty or early adulthood. The pathogenesis of HS is complex and multifactorial; a close interaction between hormonal, genetic, epigenetics factors, host-specific aspects, and environmental influences contributes to the susceptibility, onset, severity, and clinical course of this disease, although the exact molecular mechanisms are still being explored. Epigenetics is currently emerging as an interesting field of investigation that could potentially shed light on the molecular intricacies underlying HS, but there is much still to uncover on the subject. The aim of this work is to provide an overview of the epigenetic landscape involved in HS. Specifically, in this in-depth review we provide a comprehensive overview of DNA methylation/hydroxymethylation, histone modifications, and non-coding RNAs (such as microRNA-miRNA-132, miRNA-200c, miRNA-30a-3p, miRNA-100-5b, miRNA-155-5p, miRNA-338-5p) dysregulation in HS patients. An interesting element of epigenetic regulation in HS is that the persistent inflammatory milieu observed in HS lesional skin could be exacerbated by an altered methylation profile and histone acetylation pattern associated with key inflammatory genes. Deepening our knowledge on the subject could enable the development of targeted epigenetic therapies to potentially restore normal gene expression patterns, and subsequentially ameliorate, or even reverse, the progression of the disease. By deciphering the epigenetic code governing HS, we strive to usher in a new era of personalized and effective interventions for this enigmatic dermatological condition.

Overexpression of hypoxia-inducible factor-1α in hidradenitis suppurativa: the link between deviated immunity and metabolism

Hypoxia-inducible factor-1α (HIF-1α) is the master transcription factor of glycolysis, Th17 cell differentiation and suppression of regulatory T cells. In the skin and serum of patients with psoriasis vulgaris, increased expression of HIF-1α has been reported, whereas HIF-1α expression in the skin and serum of patients with hidradenitis suppurativa (HS) has not yet been studied. The objective of the study is to demonstrate is there a role for HIF-1α in the pathogenesis of hidradenitis suppurativa, and its relation to HS severity. Twenty patients suffering from hidradenitis suppurativa were included in the study. Punch biopsies were taken from lesional skin for the determination of HIF-1α expression by immunohistochemical staining, and HIF-1α gene expression by quantitative reverse transcription real time PCR. Quantification of HIF-1α protein concentration was done by enzyme-linked immunosorbent assay. Twenty socio-demographically cross-matched healthy volunteers served as controls. We found increased serum levels of HIF-1α. Literature-derived evidence indicates that the major clinical triggering factors of HS, obesity, and smoking are associated with hypoxia and enhanced HIF-1α expression. Pro-inflammatory cytokines such as tumor necrosis factor-[Formula: see text] via upregulation of nuclear factor [Formula: see text]B enhance HIF-1α expression. HIF-1α plays an important role for keratinocyte proliferation, especially for keratinocytes of the anagen hair follicle, which requires abundant glycolysis providing sufficient precursors molecules for biosynthetic pathways. Metformin via inhibition of mTORC1 as well as adalimumab attenuate HIF-1α expression, the key mediator between Th17-driven deviated immunity and keratinocyte hyperproliferation. In accordance with psoriasis, our study identifies HS as an HIF-1α-driven inflammatory skin disease and offers a new rationale for the prevention and treatment of HS by targeting HIF-1[Formula: see text] overexpression.

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.

gga-miR-20b-5p inhibits infectious bursal disease virus replication via targeting Netrin 4

MicroRNAs (miRNAs) involved host-virus interaction, affecting the replication or pathogenesis of several viruses. Frontier evidences suggested that miRNAs play essential roles in infectious bursal disease virus (IBDV) replication. However, the biological function of miRNAs and the underlying molecular mechanisms are still unclear. Here, we reported that gga-miR-20b-5p acted as a negative factor affecting IBDV infection. We found that gga-miR-20b-5p was significantly up-regulated during IBDV infection in host cells, and that gga-miR-20b-5p effectively inhibited IBDV replication via targeting the expression of host protein netrin 4 (NTN4). In contrast, inhibition of endogenous miR-20b-5p markedly facilitated viral replication associated with enhancing NTN4 expression. Collectively, these findings highlight a crucial role of gga-miR-20b-5p in IBDV replication.

DANCR promotes glioma cell autophagy and proliferation via the miR‑33b/DLX6/ATG7 axis

Long non‑coding RNAs (lncRNAs) are common in the human body. Misregulated lncRNA expression can cause a variety of diseases in the human body. The present study aimed to investigate the effect of lncRNA differentiation antagonizing non‑protein‑coding RNA (DANCR) on glioma proliferation and autophagy through the microRNA (miR)‑33b/distal‑less homeobox 6 (DLX6)/autophagy‑related 7 (ATG7) axis. Reverse transcription‑quantitative PCR was used to detect DANCR and miR‑33b expression. Cell Counting Kit‑8 assay and flow cytometry were used to detect cell proliferation and apoptosis, respectively. Transmission electron microscopy was used to determine the autophagy level by observing intracellular autophagosomes. A western blot assay was used to detect protein expression levels and determine the level of autophagy in different cells. The binding sites of miR‑33b and DANCR or DLX6 were detected using a dual‑luciferase reporter assay. A chromatin immunoprecipitation assay confirmed DLX6 as a transcript of ATG7. In vivo tumorigenesis of glioma cells was validated in nude mice. DANCR and DLX6 were highly expressed in glioma cells, while miR‑33b showed low expression in glioma cells. DANCR reduced the targeted binding of miR‑33b to DLX6 by sponging miR‑33b. The result verified that DANCR could promote ATG7 protein expression through miR‑33b/DLX6, promote intracellular autophagy and proliferation and reduce apoptosis. The present study identified the role of the DANCR/miR‑33b/DLX6/ATG7 axis in regulating autophagy, proliferation, and apoptosis in glioma cells, providing new ideas for glioma treatment.

Discovering KYNU as a feature gene in hidradenitis suppurativa

BACKGROUND

Hidradenitis suppurativa (HS) is a chronic auto-inflammatory skin condition characterized by nodules, abscesses, and fistulae in skin folds. The underlying pathogenesis of HS remains unclear, and effective therapeutic drugs are limited.

METHODS

We acquired mRNA expression profiles from the Gene Expression Omnibus (GEO) database and conducted differential expression analysis between control and HS samples using R software. Four machine learning algorithms (SVM, RF, ANN, and lasso) and WCGNA were utilized to identify feature genes. GO, KEGG, Metascape, and GSVA were utilized for the enrichment analysis. CIBERSORT and ssGSEA were employed to analyze immune infiltration.

RESULTS

A total of 29 DEGs were identified, with the majority showing up-regulation in HS. Enrichment analysis revealed their involvement in immune responses and cytokine activities. KEGG analysis highlighted pathways such as IL-17 signaling, rheumatoid arthritis, and TNF signaling in HS. Immune infiltration analysis revealed the predominant presence of neutrophils, monocytes, and CD8 T cells. Machine learning algorithms and WCGNA identified KYNU as a feature gene associated with HS. We have also identified 59 potential drugs for HS based on the DEGs. Additionally, ceRNA network analysis identified the MUC19_hsa-miR-382-5p_KYNU pathway as a potential regulatory pathway.

CONCLUSIONS

KYNU emerged as a feature gene associated with HS, and the ceRNA network analysis identified the MUC19_hsa-miR-382-5p_KYNU pathway as a potential regulator.

LncRNA GAS5 promotes spermidine‑induced autophagy through the miRNA‑31‑5p/NAT8L axis in pulmonary artery endothelial cells of patients with CTEPH

Chronic thromboembolic pulmonary hypertension (CTEPH) is a leading cause of pulmonary hypertension. The present study investigated the mechanisms of long non-coding RNA growth arrest-specific transcript 5 (GAS5) on spermidine (SP)-induced autophagy. Pulmonary artery endothelial cells (PAECs) were collected from patients with CTEPH and the rat model. Immunofluorescence, Western blots, reverse transcription-quantitative polymerase chain reaction, bioinformatics, rapid amplification of cDNA ends assays, luciferase reporter assays, RNA-binding protein immunoprecipitation assays, GFP-LC3 adenoviruses, tfLC3 assays and transmission electron microscopy were performed. The results revealed that SP-induced autophagy increased GAS5 in PAECs. The upregulation of GAS5 enhanced and the downregulation of GAS5 reversed the roles of SP in PAECs. Furthermore, GAS5 promoted SP-induced autophagy in PAECs by targeting miRNA-31-5p. The miRNA-31-5p mimic suppressed and the inhibitor promoted SP-induced autophagy. Furthermore, N-Acetyltransferase 8 Like (NAT8L) was a target gene of miRNA-31-5p and knockdown of NAT8L inhibited the autophagic levels of PAECs. In vivo, SP treatment decreased miRNA-31-5p and increased NAT8L levels, which was reversed by the knockdown of GAS5. The downregulation of GAS5 abolished the stimulatory role of SP in PAECs of CTEPH rats. In conclusion, GAS5 promoted SP-induced autophagy through miRNA-31-5p/NAT8L signaling pathways in vitro and in vivo and GAS5 may be a promising molecular marker for therapies of CTEPH.

LncRNA GNAS-AS1 knockdown inhibits keloid cells growth by mediating the miR-188-5p/RUNX2 axis

Keloid is a common dermis tumor, occurring repeatedly, affecting the quality of patients' life. Long non-coding RNAs (lncRNAs) have crucial regulatory capacities in skin scarring formation and subsequent scar carcinogenesis. The intention of this study was to investigate the mechanism and function of GNAS antisense-1 (GNAS-AS1) in keloids. Clinical samples were collected to evaluate the expression of GNAS-AS1, RUNX2, and miR-188-5p by qRT-PCR. The proliferation, migration, and invasion of HKF cells were detected by CCK-8, wound healing, and Transwell assays. The expression levels of mRNA and protein were examined through qRT-PCR and Western blot assay. Luciferase reporter assay was used to identify the binding relationship among GNAS-AS1, miR-188-5p, and Runt-related transcription factor 2 (RUNX2). GNAS-AS1 and RUNX2 expressions were remarkably enhanced, and miR-188-5p expression was decreased in keloid clinical tissues and HKF cells. GNAS-AS1 overexpression promoted cells proliferation, migration, and invasion, while GNAS-AS1 knockdown had the opposite trend. Furthermore, overexpression of GNAS-AS1 reversed the inhibitory effect of 5-FU on cell proliferation, migration, and invasion. MiR-188-5p inhibition or RUNX2 overexpression could enhance the proliferation, migration, and invasion of HKF cells. GNAS-AS1 targeted miR-188-5p to regulate RUNX2 expression. In addition, the inhibition effects of GNAS-AS1 knockdown on HKF cells could be reversed by inhibition of miR-188-5p or overexpression of RUNX2, while RUNX2 overexpression eliminated the suppressive efficaciousness of miR-188-5p mimics on HKF cells growth. GNAS-AS1 knockdown could regulate the miR-188-5p/RUNX2 signaling axis to inhibit the growth and migration in keloid cells. It is suggested that GNAS-AS1 may become a new target for the prevention and treatment of keloid.

Circulating microRNAs in Hidradenitis Suppurativa

Hidradenitis suppurativa (HS) is a pathology characterized by chronic inflammation and skin lesions. The molecular basis of the inflammatory network remains unclear; however, since microRNAs (miRNAs) are involved in the modulation of inflammation, the composition of a micro-transcriptome RNA library using the blood of HS patients was analysed here. The total miRNA expression profiles of miRNAs from HS patients was assayed by real-time qPCR. Here, compared to healthy controls, miR-24-1-5p, miR-146a-5p, miR26a-5p, miR-206, miR338-3p, and miR-338-5p expression was found significantly different in HS. Knowing the significance of the miRNA mechanism in inflammatory and immune progression, we suggest that miRNA profiles found in HS patients can be significant in understanding the pathogenesis modality and establishing efficient biomarkers for HS early diagnosis. In particular, miR-338-5p was closely related to HS invasiveness and production of cytokines and was atypically overexpressed. miR-338-5p may represent a good promise as a non-invasive clinical biomarker for HS.

Shanzhiside methylester protects against depression by inhibiting inflammation via the miRNA-155-5p/SOCS1 axis

Inflammation is a key player in the regulation of depression. Shanzhiside methylester (SM) is an iridoid glycoside with strong anti-inflammatory properties. However, the antidepressant effect of SM remains unknown. The present study aimed to investigate whether SM protects against depression by targeting inflammation. A chronic unpredictable mild stress (CUMS)-induced mouse model of depression was established to assess the antidepressant effect of SM in vivo. In addition, an LPS plus ATP-induced cellular model of inflammation was used to explore the related inflammatory mechanism. We found that both SM and miRNA-155-5p sponge markedly remedied CUMS-induced depression-like behaviors in the sucrose preference test (SPT), tail suspension test (TST), and forced swim test (FST), accompanied by decreased Iba1 expression and the production of TNF-α, IL-1β, and IL-6. Moreover, SM and miRNA-155-5p sponge upregulated the protein levels of SOCS1 and downregulated the protein expression of p-JAK2 and p-STAT3 in the hippocampus of CUMS-exposed mice. miRNA-155-5p expression was also decreased following SM and miRNA-155-5p sponge administration. Furthermore, SM repressed LPS- and ATP-induced inflammatory responses in BV2 cells by regulating the SOCS1/JAK2/STAT3 signaling pathway, which was similar to the anti-inflammatory effects induced by the miRNA-155-5p sponge. Collectively, these findings suggested that SM exerted antidepressant actions by targeting the miRNA-155-5p/SOCS1 axis.

MicroRNA Cross-Involvement in Acne Vulgaris and Hidradenitis Suppurativa: A Literature Review

Acne Vulgaris (AV) and Hidradenitis suppurativa (HS) are common chronic inflammatory skin conditions that affect the follicular units that often coexist or are involved in differential diagnoses. Inflammation in both these diseases may result from shared pathways, which may partially explain their frequent coexistence. MicroRNAs (miRNAs) are a class of endogenous, short, non-protein coding, gene-silencing or promoting RNAs that may promote various inflammatory diseases. This narrative review investigates the current knowledge regarding miRNAs and their link to AV and HS. The aim is to examine the role of these molecules in the pathogenesis of AV and HS and to identify possible common miRNAs that could explain the similar characteristics of these two diseases. Five miRNA (miR-155 miR-223-, miR-21, and miRNA-146a) levels were found to be altered in both HS and AV. These miRNAs are related to pathogenetic aspects common to both pathologies, such as the regulation of the innate immune response, regulation of the Th1/Th17 axis, and fibrosis processes that induce scar formation. This review provides a starting point for further studies aimed at investigating the role of miRNAs in AV and HS for their possible use as diagnostic-therapeutic targets.

Identification of Biomarkers and Critical Evaluation of Biomarker Validation in Hidradenitis Suppurativa: A Systematic Review

Importance

The identification and validation of biomarkers in hidradenitis suppurativa (HS) has potential to improve the understanding and management of this chronic, burdensome disease.

Objective

To systematically identify all known HS biomarkers, categorize them by biomarker type, and critically evaluate their validity according to established criteria.

Evidence Review

Eligibility criteria for this review (PROSPERO Registration 230830) included randomized clinical trials, uncontrolled clinical trials, cohort studies, case-control studies, and other observational studies with no restrictions of patient age, sex, race or ethnicity, or language of publication up until December 31, 2020. All articles were categorized into biomarker type, defined using the US Food and Drug Administration Biomarkers, Endpoints, and other Tools (BEST) glossary. Assessment of each identified biomarker was undertaken in line with the US Food and Drug Administration and European Medicines Agency guidelines for the validation of proposed biomarkers. Assessment of the strength of overall data regarding individual biomarkers was undertaken using the Grading of Recommendations, Assessment, Development, and Evaluations (GRADE) approach.

Findings

A total of 3953 nonduplicate articles were screened, of which 1429 articles were retrieved based on the include/exclusion criteria applied. After full-text screen and data extraction, 106 articles were included in this review. The evidence of strength of 6 categories of biomarkers (susceptibility/risk, diagnostic, monitoring, predictive, prognostic, and pharmacodynamic/response biomarkers) was assessed using GRADE criteria. A total of 48 biomarkers were identified with a minimum GRADE rating of moderate. Only 1 diagnostic (serum IL-2R), 1 monitoring (dermal Doppler vascularity), and 2 predictive biomarkers (epithelialized tunnels and positive family history of HS) achieved a GRADE rating of high. None of the identified biomarkers had sufficient clinical validity to be recommended for routine use in the clinical setting.

Conclusions and Relevance

Major barriers to the identification, validation, and introduction of routine biomarkers in the management of HS include lack of independent biomarker validation studies (especially assumption-free "omics"-based techniques); insufficient assessment of collinearity between identified or proposed biomarkers; and a lack of routine integration of biomarkers into the structure of clinical trials. International consensus among researchers, clinicians, and pharmaceutical stakeholders is required to standardize goals and methods and encourage biomarker integration into future HS clinical trials. This systematic review presents a number of priorities for near-term future research to overcome such barriers and limitations of biomarkers in HS.

Paradoxical hidradenitis suppurativa in Crohn's disease patients receiving infliximab: a case report and review of literature

The introduction of TNF blockers in the therapeutic armamentarium of inflammatory bowel diseases (IBD) has largely advanced the way by which clinicians manage these disorders. However, some patients develop de novo immune-mediated diseases during the treatment. We here present the case of paradoxical hidradenitis suppurativa, a chronic inflammatory skin disease characterized by the development of recurrent nodules and abscesses in intertriginous areas, in a 20-year-old, nonsmoker, normal-weight women, with no family history of hidradenitis suppurativa or IBD, diagnosed with nonstricturing nonpenetrating ileocolonic Crohn's disease in 2013, during treatment with infliximab. Infliximab discontinuation was followed by a significant improvement of skin lesions. We also discuss 22 additional cases of paradoxical hidradenitis suppurativa in IBD patients on TNF antagonists reported in the literature with the aim to identify potential risk factors for the development of such a complication. All the patients had Crohn's disease, and the majority of them were women (19/23; 82.6%). All cases occurred during therapy with anti-TNF agents [14/23 (61%) patients were treated with adalimumab and 9/23 (39%) patients were treated with infliximab]. The therapeutic approach directed at maintaining/holding the undergoing biologic therapy is still uncertain. Further studies are needed to determine the most appropriate treatment choice toward ongoing biologic therapy.

Hidradenitis Suppurativa: Where We Are and Where We Are Going

Hidradenitis suppurativa (HS) is a chronic inflammatory skin disease primarily affecting apocrine gland-rich areas of the body. It is a multifactorial disease in which genetic and environmental factors play a key role. The primary defect in HS pathophysiology involves follicular occlusion of the folliculopilosebaceous unit, followed by follicular rupture and immune responses. Innate pro-inflammatory cytokines (e.g., IL-1β, and TNF-α); mediators of activated T helper (Th)1 and Th17 cells (e.g., IFN-γ, and IL-17); and effector mechanisms of neutrophilic granulocytes, macrophages, and plasma cells are involved. On the other hand, HS lesions contain anti-inflammatory mediators (e.g., IL-10) and show limited activity of Th22 cells. The inflammatory vicious circle finally results in pain, purulence, tissue destruction, and scarring. HS pathogenesis is still enigmatic, and a valid animal model for HS is currently not available. All these aspects represent a challenge for the development of therapeutic approaches, which are urgently needed for this debilitating disease. Available treatments are limited, mostly off-label, and surgical interventions are often required to achieve remission. In this paper, we provide an overview of the current knowledge surrounding HS, including the diagnosis, pathogenesis, treatments, and existing translational studies.

MicroRNAs as biomarkers of atrophic scarring in acne: a cross-sectional analysis of 41 patients

BACKGROUND

Acne is the commonest inflammatory dermatosis seen worldwide. Atrophic acne scarring is a frequent complication, which can arise from acne of any severity. Micro (mi)RNAs are noncoding RNA molecules of 19-25 nucleotides that function as post-transcriptomic mediators of gene expression. They have demonstrated differential expression in various pathologies, such as eczema and psoriasis, allowing for a unique miRNA 'signature' profile to be established for different disease states.

AIM

To establish a miRNA signature for acne, and acne-associated atrophic scarring and to identify if a pattern of circulating miRNA is evident in patients who are prone to scarring.

METHODS

In total, 41 participants were consecutively recruited to this study. Circulating miRNA was quantified from plasma samples in all 41 patients, while in 8 patients, and in a further validation cohort of 9 patients, whole miRNAome was undertaken from tissue specimens, which included lesional, normal and where present, scarred skin.

RESULTS

Three miRNAs, miR-223, miR-21 and miR-150, were statistically significantly overexpressed in acne lesions, and notably, in clinically uninvolved skin in participants prone to scarring. In this subgroup, we also found statistically significantly elevated levels of circulating miRNA-21 and miRNA-150.

CONCLUSION

The presence of elevated levels of these specific miRNAs in the serum of patients with acne raises the potential of a blood test to identify those at risk of scarring, allowing for earlier intervention with effective therapy.

Yin and Yang: A disrupted skin microbiome and an aberrant host immune response in hidradenitis suppurativa

The skin microbiome plays an important role in maintaining skin homeostasis by controlling inflammation, providing immune education and maintaining host defense. However, in many inflammatory skin disorders the skin microbiome is disrupted. This dysbiotic community may contribute to disease initiation or exacerbation through the induction of aberrant immune responses in the absence of infection. Hidradenitis suppurativa (HS) is a complex, multifaceted disease involving the skin, innate and adaptive immunity, microbiota and environmental stimuli. Herein, we discuss the current state of HS skin microbiome research and how microbiome components may activate pattern recognition receptor (PRR) pathways, metabolite sensing pathways and antigenic receptors to drive antimicrobial peptide, cytokine, miRNA and adaptive immune cell responses in HS. We highlight the major open questions that remain to be addressed and how antibiotic therapies for HS likely influence both microbial burden and inflammation. Ultimately, we hypothesize that the two-way communication between the skin microbiome and host immune response in HS skin generates a chronic positive feed-forward loop that perpetuates chronic inflammation, tissue destruction and disease exacerbation.

Cutaneous microRNA expression in healthy Labrador and Golden retrievers and retrievers with allergic and inflammatory skin diseases

BACKGROUND

MicroRNAs (miRNA) are short, single-stranded RNA molecules that regulate gene expression in a post-transcriptional manner. Their expression is proposed to be tissue-specific and alterations in miRNA expression have been detected in many diseases.

OBJECTIVE

To compare miRNA expression in the skin of healthy Labrador and golden retrievers, and those with allergic and nonallergic dermatitis.

METHODS AND MATERIALS

Formalin-fixed and paraffin-embedded (FFPE) skin specimens from seven healthy Labrador and golden retrievers, and seven dogs with allergic skin disease were collected. A further mixed nonallergic inflammation group consisted of samples from five dogs with fungal infection, demodicosis and mast cell tumours. Total RNA was extracted and miRNA primer assays for 18 target miRNAs (miR-142, miR-363, miR-18b, miR-451, miR-146a, miR-124, miR-409, miR-193b, miR-223, miR-215, miR-155, miR-423a, miR-143, miR-1839, miR-21, miR-34b, miR-146b and miR-202) were performed, with RNU6-2 and SNORD95 as miRNAs for normalisation. The selection of miRNAs for investigation was based on reported data and a pilot study evaluating miRNA extraction from FFPE tissue specimens.

RESULTS

In the two dogs with mast cell tumours, miRNA expression was undetermined for most miRNAs, so both were excluded from analysis. Although there were differences in the miRNA expression between healthy and inflamed skin, allergic and nonallergic inflammation showed similar expression patterns.

CONCLUSION AND CLINICAL RELEVANCE

Although the number of included dogs was small, based on this study, none of the evaluated miRNAs allowed differentiation of allergic dermatitis from other inflammatory skin diseases in retriever dogs.

Circ_AFF2 facilitates proliferation and inflammatory response of fibroblast-like synoviocytes in rheumatoid arthritis via the miR-375/TAB2 axis

Circular RNAs (circRNAs) have been implicated in the pathological regulation of human diseases by acting as microRNA (miRNA) sponges to affect gene expression. CircRNA Fragile Mental Retardation 2 (circ_AFF2) was dysregulated in rheumatoid arthritis (RA), but little is known about its specific function and hidden molecular mechanism in RA. Circ_AFF2, miR-375 and TAK1-binding 2 (TAB2) expression levels were determined through the quantitative real-time polymerase chain reaction (qRT-PCR). Flow cytometry was performed to analyze cell cycle and apoptosis. Cell proliferation detection was conducted by 3-(4, 5-dimethylthiazol-2-y1)-2, 5-diphenyl tetrazolium bromide (MTT) assay. The protein levels were measured using western blot. Inflammatory response was evaluated by enzyme-linked immunosorbent assay (ELISA). RNA pull-down assay was used to select the miRNA target of circ_AFF2. The interaction between miR-375 and circ_AFF2 or TAB2 was analyzed using the dual-luciferase reporter assay. Contrasted to normal samples and fibroblast-like synoviocytes (FLS), circ_AFF2 expression was upregulated in RA blood samples and FLS-RA cells. Cell cycle, proliferation and inflammatory response were blocked while apoptosis was promoted in FLS-RA after the downregulation of circ_AFF2. In addition, circ_AFF2 could interact with miR-375 and the function of circ_AFF2 was achieved by sponging miR-375 in FLS-RA cells. Moreover, TAB2 was a target of miR-375 and miR-375 repressed RA progression by decreasing TAB2 expression in FLS-RA cells. More importantly, circ_AFF2 promoted the expression of TAB2 by targeting miR-375. These findings clarified that circ_AFF2 induced cell progression, inflammatory response in FLS-RA cells via the miR-375/TAB2 axis. Circ_AFF2 could be used as a biomarker in the diagnosis and treatment of RA.

Pb exposure triggers MAPK-dependent inflammation by activating oxidative stress and miRNA-155 expression in carp head kidney

Lead (Pb) is a toxic heavy metal and an aquatic pollutant. Various amounts of heavy metals are released into the environment through industrial discharge, causing excessive contamination of aquatic ecosystems. The head kidney is a unique immune organ of the bony fish and plays an important role in the metabolism of heavy metals. Studies of toxic Pb exposure that have investigated the head kidney of carp are limited. This study was carried out to explore the potential immunotoxicity effects of Pb and the specific related mechanisms in the carp head kidney. Pb poisoning was shown to induce the production of reactive oxygen species (ROS) and increase the expression levels of phosphorylated proteins related to the MAPK pathway, including p38, extracellular signal-regulated protein kinase (ERK), and c-Jun N-terminal kinase (JNK). We also found that microRNA-155 played a key role in regulating the production of inflammatory factors TNF-α, IL-1β, and IL-6, and the pre-miRNA-155 inhibitor reversed the Pb-induced inflammation. In conclusion, these in vitro and in vivo findings suggest that oxidative stress and the MAPKs are involved in the Pb-induced inflammasome response, and the production of microRNA-155 aggravated the occurrence of inflammation in carp head kidney.

miR-96 regulates liver tumor-initiating cells expansion by targeting TP53INP1 and predicts Sorafenib resistance

Liver tumor-initiating cells (T-ICs) contribute to tumorigenesis, progression, recurrence and drug resistance of hepatocellular carcinoma (HCC). However, the underlying mechanism for the propagation of liver T-ICs remains unclear. In the present study, our finding shows that miR-96 is upregulated in liver T-ICs. Functional studies revealed that forced miR-96 promotes liver T-ICs self-renewal and tumorigenesis. Conversely, knockdown miR-96 inhibits liver T-ICs self-renewal and tumorigenesis. Mechanistically, miR-96 downregulates TP53INP1 via its mRNA 3'UTR in liver T-ICs. Furthermore, the miR-96 expression determines the responses of hepatoma cells to sorafenib treatment. Analysis of patient cohorts and patient-derived xenografts (PDXs) further demonstrate that the miR-96 may predict sorafenib benefits in HCC patients. Our findings revealed the crucial role of the miR-96 in liver T-ICs expansion and sorafenib response, rendering miR-96 as an optimal target for the prevention and intervention of HCC.

MicroRNA-324-5p affects the radiotherapy response of cervical cancer via targeting ELAV-like RNA binding protein 1

Cervical cancer (CC) seriously threatens the health of women. Radiation therapy (RT) is the major treatment for CC. However, the recurrent CC can acquire resistance to RT. Thus, it is necessary to find a new method for reversing RT resistance in CC. It has been reported that miR-324-5p can suppress the progression of multiple cancers. However, whether it can reverse resistance to RT in CC remains unclear. qRT-PCR and Western blotting were used to detect gene and protein expression in CC cells, respectively. Cell proliferation was tested by CCK-8 assay and colony formation assay. In addition, cell apoptosis was detected by flow cytometry. Transwell assays were performed to detect cell migration. Dual luciferase reporter assay and TargetScan were used to explore the targets of microRNA-324-5p (miR-324-5p). MiR-324-5p was downregulated in CC cells. Overexpression of miR-324-5p sensitized CC cells to RT. In addition, miR-324-5p mimics significantly induced apoptosis and inhibits the migration of CC cells in the presence of ¹³⁷ Cs ionizing radiation. Furthermore, miR-324-5p sensitized CC cells to ionizing radiation by targeting ELAV-like RNA binding protein 1 (ELAVL1). MiR-324-5p overexpression affects the radiotherapy response of CC by targeting ELAVL1, which may serve as a new target for the treatment of CC.

miR-124 regulates liver cancer stem cells expansion and sorafenib resistance

Liver cancer stem cells (CSCs) contribute to tumorigenesis, progression, recurrence and drug resistance of hepatocellular carcinoma (HCC). However, the underlying mechanism for liver CSCs expansion remains unclear. Herein, we report that miR-124 is downregulated in liver CSCs and associated with the poor prognosis of HCC. Functional studies revealed that a forced expression of miR-124 inhibits liver CSCs self-renew and tumorigenesis. Conversely, miR-124 knockdown promotes liver CSCs self-renew and tumorigenesis. Mechanistically, miR-124 directly target Caveolin-1 (CAV1) via its mRNA 3'UTR in liver CSCs. Furthermore, miR-124 expression determines the responses of hepatoma cells to sorafenib treatment. The analysis of patient cohort and patient-derived xenografts (PDXs) further demonstrated that miR-124 may predict sorafenib benefits in HCC patients. In conclusion, our findings revealed the crucial role of the miR-124 in liver CSCs expansion and sorafenib response, rendering miR-124 an optimal target for the prevention and intervention in HCC.

Proceeding report of the Fourth Symposium on Hidradenitis Suppurativa Advances 2019

The Fourth Annual Symposium on Hidradenitis Suppurativa (SHSA) took place on November 1-3, 2019, at the Westin Book Cadillac Hotel in Detroit, Michigan. This symposium was a joint meeting of the US Hidradenitis Suppurativa Foundation and the Canadian Hidradenitis Suppurativa Foundation. This cross-disciplinary meeting with experts from around the world was an opportunity to discuss the most recent advances in the study of hidradenitis suppurativa (HS) pathogenesis, clinical trials, classification, scoring systems, complementary/alternative medical treatments, diet, pain management, surgical and laser treatment, and ultrasonographic assessment. A special preconference workshop was held on the use of neodymium-doped yttrium-aluminum-garnet laser hair reduction, sinus tract deroofing, and carbon dioxide laser excision with ultrasonographic mapping and tumescent anesthesia for the treatment of HS. The focused workshops on establishing an HS clinic, setting up an HS support group, the Hidradenitis Suppurativa Prospective Observational Registry and Biospecimen Repository, and wound care were held during the meeting. A special program called HS Ambassadors was established for patients who may have questions about the conference presentations, and in addition, a meet and greet for patients and HS Ambassadors was arranged. To facilitate networking between those early in their careers and clinical and research experts, a mentoring reception was held.

[Hidradenitis suppurativa/acne inversa in the genitoanal region]

Hidradenitis suppurativa/acne inversa (HS/AI) is a chronic inflammatory skin disease. Several studies showed that perianal, perineal and gluteal involvement is more common in men. Axillary, submammary and inguinal localizations seem to be more prevalent in women. Involvement of the genitoanal region is associated with a higher reduced quality of live and sexual health compared to other locations. Moreover HS/AI in the genitoanal region can lead to serious complications. The knowledge of perianal fistula formation, pubogenital lymphedema and squamous cell carcinoma, which are three of the most severe complications, is critical for adequate treatment.

MiR-486-5p inhibits the hyperproliferation and production of collagen in hypertrophic scar fibroblasts via IGF1/PI3K/AKT pathway

Background: This study explored the function and mechanism of miR-486-5p in HSFBs.Methods: Qualitative real-time-polymerase chain reaction (qRT-PCR) was performed to detect the expression of miR-486-5p in HS and hypertrophic scar fibroblasts (HSFBs). Viability, migration, invasion ability, apoptosis, and expressions of Collagen I, Collagen III, α-SMA and Cleaved caspase-3 in HSFBs after transfection with miR-486-5p mimic or inhibitor were measured by CCK-8, wound-healing, transwell, and Western blot, respectively. Interaction between miR-486-5p and IGF1 was predicted by Targetscan version 7.2 and further confirmed by dual-luciferase assay, and functional rescue experiments were conducted to verify the predicted molecular mechanism. The activation of PI3K/AKT pathway was also analyzed by Western blot.Results: MiR-486-5p was low-expressed in HS and HSFBs, and that overexpression of miR-486-5p suppressed the viability, migration, invasion, and expressions of Collagen I, Collagen III, and α-SMA of HSFBs, meanwhile, it also promoted apoptosis and Cleaved caspase-3 expression in HSFBs. Moreover, IGF1 was targeted by miR-486-5p, and increased viability, migration, invasion, and collagens expressions, the activation of PI3K/Akt pathway, and decreased apoptosis and Cleaved caspase-3 induced by miR-486-5p inhibitor could be partly alleviated by siIGF1.Conclusions: Overexpressed miR-486-5p inhibited the hyperproliferation and excessive production of collagen in HSFBs via IGF1/PI3K/AKT pathway.

Development of microRNA-21 mimic nanocarriers for the treatment of cutaneous wounds

Rationale: Of the regulatory microRNAs expressed in the wounded skin, microRNA-21 (miR21) plays a pivotal role in wound repair by stimulating re-epithelialization, an essential feature to facilitate healing and reduce scar formation. Despite their crucial roles in wound healing, synthetic exogenous microRNAs have limited applications owing to the lack of an appropriate delivery system. Herein, we designed an miR21 mimic nanocarrier system using facial amphipathic bile acid-conjugated polyethyleneimines (BA-PEI) for the intracellular and transdermal delivery of synthetic miR21 molecules to accelerate wound repair. Methods: To design miR21 mimic nanocarriers, BA-conjugated PEIs prepared from three different types of BA at molar feed ratios of 1 and 3 were synthesized. The intracellular uptake efficiency of synthetic miR21 mimics was studied using confocal laser scanning microscopy and flow cytometry analysis. The optimized miR21/BA nanocarrier system was used to evaluate the wound healing effects induced by miR21 mimics in human HaCaT keratinocytes in vitro and a murine excisional acute wound model in vivo. Results: The cell uptake efficiency of miR21 complexed with BA-conjugated PEI was dramatically higher than that of miR21 complexed with PEI alone. Deoxycholic acid (DA)-modified PEI at a molar feed ratio of 3:1 (DA3-PEI) showed the highest transfection efficiency for miR21 without any increase in toxicity. After effective transdermal and intracellular delivery of miR21/DA3 nanocarriers, miR21 mimics promoted cell migration and proliferation through the post-transcriptional regulation of programmed cell death protein 4 (PDCD4) and matrix metalloproteinases. Thus, miR21 mimic nanocarriers improved both the rate and quality of wound healing, as evident from enhanced collagen synthesis and accelerated wound re-epithelialization. Conclusion: Our miRNA nanocarrier systems developed using DA3-PEI conjugates may be potentially useful for the delivery of synthetic exogenous miRNAs in various fields.

Targeting NLRP3 Inflammasome in Inflammatory Bowel Disease: Putting out the Fire of Inflammation

Inflammatory bowel disease (IBD) is a group of inflammatory conditions of the colon and small intestine, comprised of ulcerative colitis and Crohn's disease. Among the complicated pathogenic factors of IBD, the overaction of inflammatory and immune reaction serves as an important factor. Inflammasome is a form of innate immunity as well as inflammation. Among all kinds of inflammasomes, the NOD-like receptor family, pyrin domain-containing 3 (NLRP3) inflammasome is the most studied one, and has been revealed to be involved in the pathogenesis and progression of IBD. Here, in this review, the association between the NLRP3 inflammasome and IBD will be discussed. Furthermore, several NLRP3 inflammasome inhibitors which have been demonstrated to be effective in the alleviation of IBD will be described in this review.

Silencing circular RNA circANKRD36 remits lipopolysaccharide-induced inflammatory damage by regulating microRNA-15/MyD88

Bedsore is a familiar disease, which fearfully harms the health of the patients. We investigated the efficacy and mechanism of circular RNA circANKRD36 on HaCaT cell in inflammatory damage. CCK-8 and flow cytometry were respectively used to investigate the efficacies of lipopolysaccharide (LPS), circANKRD36, and microRNA (miR)-15 on cell viability and apoptosis. Moreover, circANKRD36 and miR-15 expression were changed by cell transfection and investigated by reverse transcription-quantitative polymerase chain reaction. Furthermore, the levels of Bax, pro caspase-3, cleaved caspase-3, interleukin (IL)-1β, IL-6, and proteins of the pathway were investigated by Western blot. Otherwise, the levels of IL-1β and IL-6 were investigated by enzyme-linked immunosorbent assay. Reactive oxygen species (ROS) was investigated by ROS assay. The relation between myeloid differentiation factor 88 (MyD88) and miR-15 was investigated by luciferase assay. LPS caused inflammatory damage and upregulated circANKRD36. circANKRD36 was silenced in cells and si-circANKRD36 remitted inflammatory damage. Furthermore, si-circANKRD36 negatively regulated miR-15 and miR-15 inhibitor could reverse the efficacies of si-circANKRD36. Besides, si-circANKRD36 restrained the NF-κB pathway by upregulating miR-15. Finally, MyD88 was authenticated as a target of miR-15. circANKRD36 remitted cell inflammatory damage upregulating miR-15/MyD88 via the NF-κB pathway in HaCaT cells.

Ssc-novel-miR-106-5p reduces lipopolysaccharide-induced inflammatory response in porcine endometrial epithelial cells by inhibiting the expression of the target gene mitogen-activated protein kinase kinase kinase 14 (MAP3K14)

As an important gram-negative bacterial outer membrane component, lipopolysaccharide (LPS) plays an important role in bacterial-induced endometritis in sows. However, how LPS induces endometritis is unclear. We stimulated sow endometrial epithelial cells (EECs) with LPS and detected cell viability and tumour necrosis factor-α (TNF-α) and interleukin-1 (IL-1) secretion. LPS affected EEC viability and TNF-α and IL-1 secretion in a dose-dependent manner. LPS induced differential expression in 10 of 393 miRNAs in the EECs (downregulated, nine; upregulated, one). MicroRNA (miRNA) high-throughput sequencing of the LPS-induced EECs plus bioinformatics analysis and the dual-luciferase reporter system revealed a novel miRNA target gene: mitogen-activated protein kinase kinase kinase 14 (MAP3K14). Ssc-novel-miR-106-5p mimic, inhibitor and the nuclear factor of kappa light polypeptide gene enhancer in B-cells inhibitor, alpha (IκBα) phosphorylation inhibitor Bay11-7085 were used to detect EEC nuclear factor-κB phosphorylation levels (p-NF-κB) and TNF-α and IL-1 secretion. MiR-106-5p mimic downregulated MAP3K14 mRNA and protein expression levels, inhibited p-NF-κB levels and decreased IL-1 and TNF-α secretion, whereas miR-106-5p inhibitor had the opposite effect. Bay11-7085 inhibited p-NF-κB expression and TNF-α and IL-1 secretion. These results suggest that LPS downregulates ssc-novel-miR-106-5p expression in sow EECs to increase MAP3K14 expression, which increases p-NF-κB to promote IL-1 and TNF-α secretion.

Proceeding report of the third symposium on Hidradenitis Suppurativa advances (SHSA) 2018

The 3rd Annual Symposium on Hidradenitis Suppurativa Advances (SHSA) took place on 12-14 October 2018 at the Women's College Hospital in Toronto, Ontario, Canada. This symposium was a joint meeting of the Hidradenitis Suppurativa Foundation (HSF) founded in the USA and the Canadian Hidradenitis Suppurativa Foundation (CHSF). This cross-disciplinary meeting with experts from around the world was an opportunity to discuss the most recent advances in the study of hidradenitis suppurativa pathogenesis, epidemiology, classification, scoring systems, radiologic diagnosis, treatment approaches and psychologic assessment. Two special sessions this year were HS as a systemic disease and HS management guidelines. There were focused workshops on wound healing and ultrasound. There were two sessions primarily for patients and their families in the HS School programme: One workshop focused on mindfulness, and the second involved discussion among clinicians and patients about various disease aspects and the latest management. To facilitate networking between clinical and research experts and those early in their career, a mentoring breakfast was held.

An Integrated Approach to Unravel Hidradenitis Suppurativa Etiopathogenesis

Hidradenitis suppurativa/acne inversa (HS) is a chronic inflammatory disease involving hair follicles that presents with painful nodules, abscesses, fistulae, and hypertrophic scars, typically occurring in apocrine gland bearing skin. Establishing a diagnosis of HS may take up to 7 years after disease onset. HS severely impairs the quality of life of patients and its high frequency causes significant costs for health care system. HS patients have an increased risk of developing associated diseases, such as inflammatory bowel diseases and spondyloarthropathies, thereby suggesting a common pathophysiological mechanism. Familial cases, which are around 35% of HS patients, have allowed the identification of susceptibility genes. HS is perceived as a complex disease where environmental factors trigger chronic inflammation in the skin of genetically predisposed individuals. Despite the efforts made to understand HS etiopathogenesis, the exact mechanisms at the basis of the disease need to be still unraveled. In this review, we considered all OMICs studies performed on HS and observed that OMICs contribution in the context of HS appeared as not clear enough and/or rich of useful clinical information. Indeed, most studies focused only on one aspect—genome, transcriptome, or proteome—of the disease, enrolling small numbers of patients. This is quite limiting for the genetic studies, from different geographical areas and looking at a few aspects of HS pathogenesis without any integration of the findings obtained or a comparison among different studies. A strong need for an integrated approach using OMICs tools is required to discover novel actors involved in HS etiopathogenesis. Moreover, we suggest the constitution of consortia to enroll a higher number of patients to be analyzed following common and consensus OMICs strategies. Comparison and integration with the findings present in the OMICs repositories are mandatory. In a theoretic pipeline, the Skin-OMICs profile obtained from each HS patient should be compared and integrated with repositories and literature data by using appropriate InterOMICs approach. The final goal is not only to improve the knowledge of HS etiopathogenesis but also to provide novel tools to the clinicians with the eventual aim of offering a tailored treatment for HS patients.

Long-Wave Medical Infrared Thermography: A Clinical Biomarker of Inflammation in Hidradenitis Suppurativa/Acne Inversa

BACKGROUND

A more reliable classification of skin inflammation and severity of active disease results from ultrasound sonography and the new hidradenitis suppurativa/acne inversa (HS) classification system IHS4. However, an objective assessment of skin inflammation in a continuous mode is still the ultimate goal. Long-wave medical infrared thermography (MIT) may offer a blood flow and temperature differential assessment in inflammatory conditions.

OBJECTIVE

To evaluate the application of MIT in HS.

METHODS

Standardized photography of the areas involved or been candidates for HS involvement was performed and MIT pictures were taken simultaneously and superimposed on the photographs of 18 patients (11 female, 7 male, median age 38.75 years [95% confidence interval 28.5 and 51 years], Hurley score I 5.6%, Hurley score II 38.9%, and Hurley score III 55.5%). A modification of the Otsu's method facilitated the automatic lesion segmentation from the background, depicting the inflammation area. Moreover, MIT was administered in real-time mode during radical HS surgery.

RESULTS

A 1°C temperature difference from a corresponding symmetric body region was indicative of inflammation. MIT figures detected a gradual increase of skin temperature from 33.0°C in healthy skin on average to 35.0-36.6°C at the center of inflamma tory lesions in the axilla and to 35.4-36.9°C at the center of inflammation in the groin area. Real-time MIT assessment enabled the definition of the margins and depth of the surgical intervention during the procedure.

CONCLUSION

MIT is a promising tool for the detection of inflammation severity in HS lesions and can be used as a clinical biomarker in evaluation studies of medical and surgical HS treatment.

Nicastrin/miR-30a-3p/RAB31 Axis Regulates Keratinocyte Differentiation by Impairing EGFR Signaling in Familial Acne Inversa

Nicastrin (NCSTN) mutations are associated with familial acne inversa (AI), and emerging evidence suggests that microRNAs (miRNAs) are involved in various skin diseases. However, whether NCSTN mutations affect miRNA levels and their subsequent signaling pathways in familial AI patients has not been studied. We aimed to elucidate the relationship between NCSTN mutations and familial AI pathogenesis by investigating differential miRNA expression and their related pathways. Combined with miRNA microarray data from familial AI patients, Ncstn keratinocyte-specific-knockout (Ncstn^ΔKC) mice and bioinformatics predictions showed that NCSTN mutations led to decreased miR-30a-3p levels, which negatively regulated RAB31 expression. Moreover, enhanced RAB31 levels accelerated degradation of activated EGFR, leading to abnormal differentiation in keratinocytes. The impaired EGFR signaling and its effects on epidermal differentiation were also observed in familial AI patients and Ncstn^ΔKC mice. Thus, our study showed that miR-30a-3p/RAB31/EGFR signaling pathway may play a key role in the pathogenesis of familial AI with NCSTN mutations.

T helper 17 cell/regulatory T-cell imbalance in hidradenitis suppurativa/acne inversa: the link to hair follicle dissection, obesity, smoking and autoimmune comorbidities

BACKGROUND

Disintegration of the infundibula of terminal hair follicles (HFs) in intertriginous skin areas exhibits the histological hallmark of hidradenitis suppurativa (HS)/acne inversa, featuring a dissecting terminal hair folliculitis. Elevated serum levels of interleukin (IL)-17 and local increase in the ratio of proinflammatory T helper (Th)17 cells and anti-inflammatory regulatory T cells (Tregs) have been reported. Perifollicular Tregs play a key role in HF stem cell homeostasis and infundibular integrity.

OBJECTIVES

In this review, we evaluate the Th17/Treg ratio in HS, its aggravating conditions and associated comorbidities. Furthermore, we intended to clarify whether drugs with reported beneficial effects in the treatment of HS readjust the deviated Th17/Treg axis.

METHODS

PubMed-listed, peer-reviewed original research articles characterizing Th17/Treg regulation in HS/acne inversa and associated comorbidities were selected for this review.

RESULTS

This review presents HS as a disease that exhibits an increased Th17/Treg ratio. Perifollicular deficiencies in Treg numbers or function may disturb HF stem cell homeostasis, initiating infundibular dissection of terminal HFs and perifollicular inflammation. The Th17/Treg imbalance is aggravated by obesity, smoking and decreased Notch signalling. In addition, HS-associated autoimmune diseases exhibit a disturbed Th17/Treg axis resulting in a Th17-dominant state. All drugs that have beneficial effects in the treatment of HS normalize the Th17/Treg ratio.

CONCLUSIONS

HS immunopathogenesis is closely related to deviations of the Th17/Treg balance, which may negatively affect Treg-controlled HF stem cell homeostasis and infundibular integrity. Pharmacological intervention should not only attenuate Th17/IL-17 signalling, but should also improve Treg function in order to stabilize HF stem cell homeostasis and infundibular integrity.

Hidradenitis suppurativa: an update on connecting the tracts

Hidradenitis suppurativa (HS) is a devastating disease involving abscesses, sinus tracts, and inflammation classically affecting the axilla, groin, and/or anogenital region. Although the disease pathogenesis is not fully understood, recent advances suggest that HS pathology runs much deeper than the cutaneous manifestations. It is now believed that HS is a systemic inflammatory disease that gives rise to the characteristic cutaneous manifestations. This disease is problematic for both patients and physicians to manage because of a variety of diagnostic and management difficulties. This article seeks to provide updates on the current understanding of HS to increase awareness and improve management.

MiR-146a/b: a family with shared seeds and different roots

MicroRNAs are small, noncoding, RNAs known for their powerful modulation of molecular processes, making them a major focus for studying pathological mechanisms. The human miR-146 family of microRNAs consists of two member genes, MIR146A and MIR146B These two microRNAs are located on different chromosomes and exhibit differential regulation in many cases. However, they are nearly identical in sequence, sharing a seed region, and are thus predicted to target the same set of genes. A large proportion of the microRNA (miR)-146 literature focuses on its role in regulating the innate immune response in the context of various pathologies by modulating two widely studied target genes in the toll-like receptor signaling cascade. A growing subset of the literature reports a role of miR-146 in cardiovascular and renal disease, and data suggest there is exciting potential for miR-146 as a diagnostic and therapeutic target. Nevertheless, the published literature is confounded by unclear and imprecise language concerning the specific effects of the two miR-146 family members. The present review will compare the genomic origin and regulation of miR-146a and miR-146b, discuss some approaches to overcome analytical and experimental challenges, and summarize findings in major areas of miR-146 research. Moving forward, careful evaluation of miR-146a/b specificity in analytical and experimental approaches will aid researchers in elucidating the functional relevance of differential regulation of the miR-146 family members in health and disease.