Vesicular hand eczema transcriptome analysis provides insights into its pathophysiology

Transcriptomic profiling of chronic hand eczema skin reveals shared immune pathways and molecular drivers across subtypes

BACKGROUND

Chronic hand eczema (CHE) is a common skin disease with different subtypes, but knowledge of the molecular patterns associated with each subtype is limited.

OBJECTIVE

We sought to characterize the CHE transcriptome across subtypes.

METHODS

Using RNA sequencing, we studied the transcriptome of 220 full-thickness skin biopsy samples collected from palms, dorsa, and arms from 96 patients with CHE and/or atopic dermatitis (AD) and 32 healthy controls. The primary analysis focused on 16 healthy and 54 lesional CHE palm samples that were further stratified by AD status and unique etiology. Differentially expressed genes (DEGs) were identified across the cohort, and Ingenuity Pathway Analysis (IPA) was used for pathway analysis and upstream regulator prediction.

RESULTS

We identified anatomic site-specific transcriptomic variations, showing unique characteristics in both healthy and CHE-affected palm skin. In CHE palms, we identified 2333 DEGs versus healthy palms. Upregulated genes predominantly involved keratinocyte host inflammation and immune signaling, while downregulated genes were linked to lipid metabolism and epidermal barrier function. IPA revealed numerous activated proinflammatory pathways, dominated by TH1 and TH2. Key upstream regulators included type 1 (IFN-γ, TNF, STAT1, IL-2) and type 2 (IL-4) associated molecules, and IL-1β. Lesional palm signatures were broadly shared across CHE subtypes. No DEGs were found between allergic and irritant contact dermatitis CHE. Subtype-specific pathway and upstream regulator activity variations were noted.

CONCLUSION

The lesional CHE transcriptome is primarily shared among subtypes and is characterized by activation of several immune pathways, dominated by TH1 and TH2. Key shared upstream regulators were identified, highlighting potential universal therapeutic targets.

Skin Tape Stripping Reveals Distinct Biomarker Profiles in Chronic Hand Eczema of Patients With and Without Comorbid Atopic Dermatitis

INTRODUCTION

Chronic hand eczema (CHE) is a highly prevalent inflammatory skin condition which is often resistant to conventional treatments. Molecular insights of CHE remain limited. Tape stripping combined with high-throughput RNA sequencing can now provide a better insight into CHE pathogenesis in a minimally invasive fashion.

METHODS

We collected tape strip samples from lesional and non-lesional skin of 66 patients with moderate-to-severe CHE, comprising 33 with and 33 without comorbid atopic dermatitis (AD), and performed bulk RNA sequencing. Results were compared to tape strips from palmar skin of age/race/sex-matched healthy controls (HC). Differentially expressed genes (DEGs) (fold change/FCH > 1.5 and false discovery rate/FDR < 0.05) were calculated and correlated with clinical severity scores including hand eczema severity index (HECSI) and modified total lesion symptoms score (mTLSS).

RESULTS

Tape strip isolates detected a common phenotype in CHE lesions regardless of AD status, including upregulated type-1 (IL12RB2, IFNGR1, IFNGR2, MX1) and type-2-associated inflammatory mediators (CCL22, CCL24, OX40/TNFRSF4, TSLPR/CRLF2, GATA3), paralleled by downregulated epidermal barrier markers (i.e., FLG or LORICRIN). Non-lesional skin demonstrated a similar, albeit milder, dysregulation pattern, with additional reduction in type-17 pathways. Lesional skin of CHE patients without AD showed greater skewing towards type-1 immunity (IL15RA, CXCL9), while CHE from AD patients showed a more pronounced type-2 inflammatory pattern (IL13, CCL17) and their gene expression biomarkers had greater and more significant correlations with clinical severity markers.

CONCLUSION

Tape stripping can capture detailed immune and skin barrier abnormalities in CHE and identify potential novel subtype-specific treatment targets. Stronger correlations in patients with AD suggest a more homogenous disease phenotype than in CHE non-AD patients.

TRIAL REGISTRATION

NCT03728504.

Hand eczema

Hand eczema is a highly prevalent skin disease and one of the most common work-related disorders. In up to two-thirds of individuals affected by hand eczema, the disease becomes chronic and results in substantial personal and occupational disability. Manifestations of chronic hand eczema vary in severity and appearance over time, and people with eczema typically experience itch, pain, and a burning sensation. The pathophysiology of chronic hand eczema is multifactorial. Major risk factors are current or past atopic dermatitis and excessive or prolonged exposure to irritants or allergens. Based on the suspected main causes, chronic hand eczema is commonly classified into irritant, allergic, and atopic hand eczema. Diagnosis and assessment can be complex, and management is often challenging. Strategies include structured education, avoidance of trigger factors, primary to tertiary prevention, topical anti-inflammatory treatment with glucocorticosteroids, calcineurin inhibitors, or januskinase inhibitors, phototherapy, systemic retinoids, and off-label use of immunosuppressive drugs. Topical and systemic immunomodulatory therapies approved for atopic dermatitis could be used in severe atopic hand eczema and some of them are under clinical development for chronic hand eczema. Additional research is needed to better understand chronic hand eczema subtypes and underlying mechanisms, and the comparative effectiveness and safety of therapies. This Review combines established knowledge with ongoing changes in our understanding of the disease and their implications for prevention, management, and future research.

Chronic Hand Eczema

Chronic hand eczema (CHE) is a complex, challenging, and frequently multifactorial skin disease of the hands. It is very common in the general population, especially in certain professions. When hand eczema (HE) persists for longer than 3 months or has a minimum of two relapses per year after initial manifestation with complete clearance, it is considered chronic. In this case, health-related quality of life and the patient's working life are often impaired. CHE can be considered as an umbrella term because it covers different clinical pictures and etiologies. To date, there is no definite and unique HE classification. Treatment starts with identifying the individual HE etiology paralleled by symptomatic therapy (local and/or systemic and/or ultraviolet phototherapy). Sustainable management of HE requires the identification and avoidance of its triggering factors, from the professional and private environment. This includes ruling out allergic contact dermatitis if any HE persists for more than 3 months despite adequate therapy. Randomized controlled trials investigating the efficacy in HE are lacking for several treatment modalities. Patient education measures of skin protection and prevention complete the multimodal treatment.

Transcriptomics- and Genomics-Guided Drug Repurposing for the Treatment of Vesicular Hand Eczema

Vesicular hand eczema (VHE), a clinical subtype of hand eczema (HE), showed limited responsiveness to alitretinoin, the only approved systemic treatment for severe chronic HE. This emphasizes the need for alternative treatment approaches. Therefore, our study aimed to identify drug repurposing opportunities for VHE using transcriptomics and genomics data. We constructed a gene network by combining 52 differentially expressed genes (DEGs) from a VHE transcriptomics study with 3 quantitative trait locus (QTL) genes associated with HE. Through network analysis, clustering, and functional enrichment analyses, we investigated the underlying biological mechanisms of this network. Next, we leveraged drug-gene interactions and retrieved pharmaco-transcriptomics data from the DrugBank database to identify drug repurposing opportunities for (V)HE. We developed a drug ranking system, primarily based on efficacy, safety, and practical and pricing factors, to select the most promising drug repurposing candidates. Our results revealed that the (V)HE network comprised 78 genes that yielded several biological pathways underlying the disease. The drug-gene interaction search together with pharmaco-transcriptomics lookups revealed 123 unique drug repurposing opportunities. Based on our drug ranking system, our study identified the most promising drug repurposing opportunities (e.g., vitamin D analogues, retinoids, and immunomodulating drugs) that might be effective in treating (V)HE.

Efficacy and Safety of Dupilumab in the Treatment of Hand Eczema: A Retrospective Study

Background: Hand eczema (HE) is a prevalent chronic condition that exerts a substantial and enduring adverse effect on quality of life (QoL) and imposes an economic burden on society. Managing HE poses challenges due to the limited effectiveness and potential adverse effects associated with many currently available topical and systemic treatments. Methods: This article examines twenty-one patients affected by HE treated with dupilumab, a fully human monoclonal antibody targeting interleukin IL-4 and IL-13 signaling. This involves a retrospective descriptive statistical analysis. Results: At week 6, HECSI-75 was achieved by 12 patients (57.9%). The proportion of patients meeting the HECSI-75 criteria steadily increased over the observation weeks, reaching 90% at week 16 and 100% at week 104. Furthermore, HECSI-90 and HECSI-100 were achieved by 75% and 60% of patients at week 16 and by 100% and 85% of patients at week 68, respectively. All patients who reached week 104 maintained complete disease remission according to HECSI 100. Conclusions: In all patients, dupilumab was shown to be an effective drug in achieving disease clearance, as indicated by all the parameters considered at each evaluation point (Week 6, Week 16, Week 32, Week 52, Week 68, Week 84, and Week 104), in comparison to the initial baseline.

Real-World Clinical Experience of Dupilumab in the Treatment of Chronic Palmo-Plantar Eczema in Patients with Moderate-Severe Atopic Dermatitis: 52-Week Follow-Up

Background: Hand-foot eczema (HFE) are special locations of dermatitis, which are often associated with atopic dermatitis (AD) and have a significant negative impact on the quality of life, demanding a clinically relevant improvement. Objectives: To evaluate the effectiveness and safety of dupilumab in the treatment of eczema localized in hands and/or feet in patients with moderate-to-severe AD. Methods: Retrospective multicenter study of adult patients with HFE treated with dupilumab for their AD. Patients with other concomitantly systemic immunosuppressive treatments did not undergo a washout period. The severity of palmar and/or plantar involvement was assessed using the Physician Global Assessment (PGA) scale on a scale of 0 ( = clear) to 5 ( = very severe). Eczema Area and Severity Index (EASI) and NRS-pruritus scales were also evaluated. One hundred percent of patients reached week 16, while 67/84 reached week 52 of follow-up. Results: A total of 84 patients were included 86.69% of patients showed a reduction in PGA-Hand, and 80.34% in PGA-Foot at week 52, EASI improvement was reached by 83.55% of patients at week 16 and 87.35% at week 52. Reduction of pruritus (≥4 points in NRS-pruritus scale) was 73.01% at week 16 and 80.67% at week 52. No differences in response to dupilumab were observed in the different subtypes of palmo-plantar dermatitis. Conclusions: The results obtained in our study suggest that dupilumab may be an effective and safe therapeutic option for the treatment of dermatitis localized in hands and/or feet.

Transcriptional differences between vesicular hand eczema and atopic dermatitis

BACKGROUND

Transcriptome analyses of vesicular hand eczema (VHE) indicated a large overlap with atopic dermatitis (AD). However, differentially expressed genes (DEGs) that differentiate VHE from AD are unknown.

OBJECTIVE

To identify distinctive transcriptional features of VHE in comparison to AD.

METHODS

We re-analysed RNA sequencing data of 10 lesional palmar VHE epidermal biopsies and performed DEG analyses. We adjusted the obtained DEG results of 57 lesional whole AD skin biopsies of the upper extremities or trunk to our criteria. Up- and down-regulated DEGs in both skin diseases, VHE-only, AD-only, and opposite regulated DEGs were identified. Enrichment analyses and Chi-squared tests were conducted to test for differences in gene set enrichment between both skin diseases.

RESULTS

Comparing 3028 DEGs in VHE (1645 up; 1383 down) with 5391 DEGs in AD (3842 up; 1549 down), revealed 1516 shared DEGs (1179 up; 337 down) and 1512 DEGs unique to VHE (466 up, 1046 down). Interferon signalling and necroptosis were significantly more prominent in VHE compared to AD. Downregulated genes identified only in VHE (like DNASE1L2, KRT2, KRT9 and KRT25) indicate an aberrant epidermal differentiation.

CONCLUSION

Our study indicates a common pathophysiology between VHE and AD, but also reveals transcriptional differences between VHE and AD.

Efficacy and safety of dupilumab in patients with severe chronic hand eczema with inadequate response or intolerance to alitretinoin: a randomized, double-blind, placebo-controlled phase IIb proof-of-concept study

BACKGROUND

Effective treatment options for patients with chronic hand eczema (CHE) are scarce. Dupilumab is licensed for the treatment of moderate-to-severe atopic dermatitis and has shown promising results for the treatment of hand eczema in other studies.

OBJECTIVES

To evaluate the efficacy and safety of dupilumab in adult patients with severe CHE (subtypes recurrent vesicular hand eczema or chronic fissured hand eczema) who have an inadequate response/intolerance to alitretinoin, or when alitretinoin is medically inadvisable.

METHODS

In this 16-week, randomized, double-blind, placebo-controlled proof-of-concept phase IIb trial, patients with severe CHE were randomized 2 : 1 to dupilumab 300 mg or placebo subcutaneously every 2 weeks. Patients visited the outpatient clinic at the initiation of the study drug, and every 4 weeks until 16 weeks of treatment. The primary endpoint was the proportion of patients achieving at least a 75% improvement on the Hand Eczema Severity Index score (HECSI-75) at week 16. Adverse events were monitored during each visit. The study was registered on ClinicalTrials.gov (identifier NCT04512339).

RESULTS

In total, 30 patients were randomized, and 29 patients received the assigned study drug (dupilumab n = 20, placebo n = 9). At week 16, more patients achieved HECSI-75 in the dupilumab group than in the placebo group {95% [95% confidence interval (CI) 73.1-99.7] vs. 33% [95% CI 9.0-69.1]}. Dupilumab also showed greater least square mean percentage change from baseline to week 16 in peak pruritus Numerical Rating Scale compared with placebo [-66.5 ± 10.7 (95% CI -88.6 to -44.5) vs. -25.3 ± 17.0 (95% CI -60.1-9.4)]. Adverse events were similar for the dupilumab and placebo groups and were mostly mild. There were no serious adverse events, nor did any of the adverse events lead to discontinuation of the study drug.

CONCLUSIONS

Dupilumab was efficacious and well tolerated. Larger studies of longer duration are needed to provide more evidence on the -efficacy of dupilumab in CHE. Moreover, larger studies could also enable comparisons between clinical subtypes or aetiological -diagnoses.

Circulating biomarkers are associated with disease severity of chronic hand eczema and atopic dermatitis

BACKGROUND

Although chronic hand eczema (CHE) is a highly prevalent and disabling skin disease, it is currently unknown if CHE is associated with systemic inflammation.

OBJECTIVES

To characterize the plasma inflammatory signature of CHE.

METHODS

Using Proximity Extension Assay technology, we assessed 266 inflammatory and cardiovascular disease risk proteins in the plasma of 40 healthy controls, 57 patients with atopic dermatitis (AD) with active lesions, 11 with CHE and a history of AD (CHEPREVIOUS_AD), and 40 with CHE and no history of AD (CHENO_AD). Filaggrin gene mutation status was also assessed. Protein expression was compared between groups and according to disease severity. Correlation analyses for biomarkers, and clinical- and self-reported variables, were performed.

RESULTS

Very severe CHENO_AD was associated with systemic inflammation when compared with controls. Levels of T helper (Th)2- and Th1-, general inflammation and eosinophil activation markers increased with severity of CHENO_AD, primarily being significantly increased in very severe disease. Significant, positive correlations were found between markers from these pathways and severity of CHENO_AD. Moderate-to-severe but not mild AD displayed systemic inflammation. The Th2 markers C-C motif chemokine (CCL)17 and CCL13 (also known as monocyte chemotactic protein 4) were the top differentially expressed proteins in both very severe CHENO_AD and moderate-to-severe AD, showing a higher fold change and significance in AD. CCL17 and CCL13 levels further correlated positively with disease severity in both CHENO_AD and AD.

CONCLUSIONS

Systemic Th2-driven inflammation is shared between very severe CHE with no history of AD, and moderate-to-severe AD, suggesting that Th2 cell targeting could be effective in several CHE subtypes.

Investigations into the filaggrin null phenotype: showcasing the methodology for CRISPR/Cas9 editing of human keratinocytes

Ever since the association between filaggrin (FLG) loss-of-function mutations and ichthyosis vulgaris and atopic dermatitis disease onset was identified, filaggrins function has been under investigation. Intra-individual genomic predisposition, immunological confounders, and environmental interactions complicate the comparison between FLG genotypes and related causal effects. Using CRISPR/Cas9, we generated human FLG knockout (ΔFLG) N/TERT-2G keratinocytes. Filaggrin deficiency was demonstrated by immunohistochemistry of human epidermal equivalent (HEE) cultures. Next to (partial) loss of structural proteins (IVL, HRNR, KRT2, and TGM1), the stratum corneum was more dense and lacked the typical basket weave appearance. In addition, electrical impedance spectroscopy and transepidermal water loss analyses highlighted a compromised epidermal barrier in ΔFLG-HEEs. Correction of FLG reinstated the presence of keratohyalin granules in the stratum granulosum, filaggrin protein expression, and expression of aforementioned proteins. The beneficial effects on stratum corneum formation were reflected by normalization of EIS and TEWL. This study demonstrates the causal phenotypical and functional consequences of filaggrin deficiency, indicating filaggrin is not only central in epidermal barrier function but also vital for epidermal differentiation by orchestrating the expression of other important epidermal proteins. These observations pave the way to fundamental investigations into the exact role of filaggrin in skin biology and disease.

Deep proteome profiling reveals signatures of age and sex differences in paw skin and sciatic nerve of naïve mice

The age and sex of studied animals profoundly impact experimental outcomes in biomedical research. However, most preclinical studies in mice use a wide-spanning age range from 4 to 20 weeks and do not assess male and female mice in parallel. This raises concerns regarding reproducibility and neglects potentially relevant age and sex differences, which are largely unknown at the molecular level in naïve mice. Here, we employed an optimized quantitative proteomics workflow in order to deeply profile mouse paw skin and sciatic nerves (SCN) - two tissues implicated in nociception and pain as well as diseases linked to inflammation, injury, and demyelination. Remarkably, we uncovered significant differences when comparing male and female mice at adolescent (4 weeks) and adult (14 weeks) age. Our analysis deciphered protein subsets and networks that were correlated with the age and/or sex of mice. Notably, among these were proteins/biological pathways with known (patho)physiological relevance, e.g., homeostasis and epidermal signaling in skin, and, in SCN, multiple myelin proteins and regulators of neuronal development. Extensive comparisons with available databases revealed that various proteins associated with distinct skin diseases and pain exhibited significant abundance changes in dependence on age and/or sex. Taken together, our study uncovers hitherto unknown sex and age differences at the level of proteins and protein networks. Overall, we provide a unique proteome resource that facilitates mechanistic insights into somatosensory and skin biology, and integrates age and sex as biological variables - a prerequisite for successful preclinical studies in mouse disease models.

A systematic analysis of C5ORF46 in gastrointestinal tumors as a potential prognostic and immunological biomarker

Background: Chromosome 5 open reading frame 46 (C5ORF46), also known as antimicrobial peptide with 64 amino acid residues (AP-64) and skin and saliva-secreted protein 1 (SSSP1), belongs to the family of open reading frame genes and encodes a small exosomal protein. C5ORF46 has been implicated in antibacterial activity and associated with patient prognosis in pancreatic cancer, colorectal cancer, and stomach cancer. These findings highlight the importance of C5ORF46 in gastrointestinal (GI) tumor inception and development. However, the prognostic and immunological value of C5ORF46 in human GI tumors remains largely unknown. In this study, we sought to explore the potential value of C5ORF46 in GI tumor prognosis and immunology.

Method: RNA sequencing (RNA-seq) was performed on the tumor and tumor-adjacent normal samples we collected to identify potential target genes for GI tumors. Apart from our RNA-seq data, all original data were downloaded from The Cancer Genome Atlas (TCGA) database and integrated via Strawberry Perl (v 5.32.0) and R (v 4.1.1). The differential expression of C5ORF46 was examined with Oncomine, Tumor Immune Estimation Resource (TIMER), Gene Expression Profiling Interactive Analysis (GEPIA), Cancer Cell Line Encyclopedia (CCLE), the Human Protein Atlas (HPA) and TCGA databases. The c-BioPortal database was used to investigate the genomic alterations of C5ORF46. The effect of C5ORF46 on prognosis and clinical phenotypes was explored via bioinformatics analyses on the TCGA and GEPIA databases. We used the bioinformatics analyses based on the TCGA database to analyze tumor mutational burden (TMB), microsatellite instability (MSI), tumor immune cell infiltration, and the correlations between C5ORF46 expression and several immune-related genes. Kyoto Encyclopedia of Genes and Genomes (KEGG) pathway enrichment analysis was carried out via the DAVID website and presented as bubble charts using ShengXinRen online tools. Gene set enrichment analysis (GSEA) was performed using R scripts based on data downloaded from the GSEA website. Immunohistochemistry (IHC) was used to validate the expression of C5ORF46 in GI tumors.

Results: The results of our RNA-seq data indicated a critical role for C5ORF46 in colon carcinogenesis. Consistently, we demonstrated that C5ORF46 was highly expressed in tumor tissues compared to normal tissues in human GI tumors. Moreover, a strong correlation was observed between C5ORF46 expression levels and patient prognosis, staging, TMB, MSI, and immune cell infiltration. Further, C5ORF46 presented as an important regulator in the tumor microenvironment (TME) and was active in the regulation of cancer immune functions. C5ORF46 is significantly correlated with genes regulating inflammation and immune responses.

Conclusion:C5ORF46 may serve as a biomarker for GI tumor prognosis and immunology. C5ORF46 could be a novel target for GI tumor immunotherapy.

The long-term effect of dupilumab on chronic hand eczema in patients with moderate to severe atopic dermatitis - 52 week results from the Dutch BioDay registry

Background

The hands are a common predilection site of atopic dermatitis (AD). Dupilumab is licensed for the treatment of AD but not for chronic hand eczema (CHE), while CHE is challenging to treat.

Objectives

To evaluate the long‐term effect of dupilumab on hand eczema (HE) in patients with AD from the BioDay Registry.

Methods

A prospective observational study of adult patients with HE, treated for AD with dupilumab. Patients with a HE severity of at least moderate at baseline were considered for analysis. Patients with other concomitantly systemic immunosuppressive treatments were excluded. Clinical effectiveness on HE severity, using the Hand Eczema Severity Index (HECSI) and photographic guide, and health‐related quality of life, using the Quality of Life in Hand Eczema Questionnaire (QOLHEQ), were evaluated.

Results

A total of 72 patients were included. HECSI‐75 was achieved by 54/62 patients (87.1%) and HECSI‐90 by 39/72 (62.9%) at 52 weeks. Based on the photographic guide, 56/62 patients (90.3%) achieved the endpoint of ‘clear’ or ‘almost clear’. Mean QOLHEQ reduction was −63.5% (95% confidence interval −38.23 to −27.41). There was no difference in response between HE subtypes.

Conclusions

The results from this study hold promise for dupilumab to be a suitable treatment option for isolated CHE.