Cornulin, a marker of late epidermal differentiation, is down-regulated in eczema

Efficacy and safety of pyrotinib combined with albumin-bound paclitaxel as first-line treatment for HER2-positive metastatic breast cancer in patients previously treated with adjuvant and/or neoadjuvant trastuzumab therapy: The stage 1 results of a single-arm, phase 2 prospective clinical trial

OBJECTIVE

It has been observed that the prognosis of patients with HER2-positive metastatic breast cancer has improved significantly with HER2-targeted agents. However, there is still a lack of evidence regarding first-line anti-HER2 treatment options for patients who have received adjuvant and/or neoadjuvant trastuzumab for HER2-positive metastatic breast cancer. Besides, there are no reliable markers that can predict the efficacy of anti-HER2 treatment in these patients.

METHODS

Patients who have received adjuvant and/or neoadjuvant trastuzumab for HER2-positive metastatic breast cancer were enrolled. Pyrotinib plus albumin-bound paclitaxel were used as first-line treatment. The primary endpoint was the objective response rate (ORR). The safety profile was also assessed. In order to explore predictive biomarkers using Olink technology, blood samples were collected dynamically.

RESULTS

From December 2019 to August 2023, the first stage of the study involved 27 eligible patients. It has not yet reached the median PFS despite the median follow-up being 17.8 months. Efficacy evaluation showed that the ORR was 92.6%, and the DCR was 100%. Adverse events of grade 3 or higher included diarrhoea (29.6%), leukopenia (11.1%), neutropenia (25.9%), oral mucositis (3.7%), and hand-foot syndrome (3.7%). Toll-like receptor 3 (TLR3) and Proto-oncogene tyrosine-protein kinase receptor (RET) were proteins with significant relevance to PFS in these patients.

CONCLUSIONS

This study demonstrates that pyrotinib plus albumin-bound paclitaxel as a first-line treatment regimen shows good efficacy and manageable safety for patients who have received adjuvant and/or neoadjuvant trastuzumab for HER2-positive metastatic breast cancer. Besides, a significant association was identified between the expression levels of TLR3 and RET and the PFS in patients.

Non-IgE-reactive allergen peptides deteriorate the skin barrier in house dust mite-sensitized atopic dermatitis patients

Atopic dermatitis (AD) is a chronic inflammatory skin disease characterized by type 2 cytokine-driven skin inflammation and epithelial barrier dysfunction. The latter is believed to allow the increased penetration of chemicals, toxins, and allergens into the skin. House dust mite allergens, particularly Der p 2, are important triggers in sensitized individuals with AD; the precise actions of these allergens in epithelial biology remain, however, incompletely understood. In this study, we compared the effects of the protein allergen Der p 2 and a mix of non-IgE-reactive Der p 2 peptides on skin cells using patch tests in AD patients and healthy participants. We then analyzed mRNA expression profiles of keratinocytes by single-cell RNA-sequencing. We report that existing barrier deficiencies in the non-lesional skin of AD patients allow deep penetration of Der p 2 and its peptides, leading to local microinflammation. Der p 2 protein specifically upregulated genes involved in the innate immune system, stress, and danger signals in suprabasal KC. Der p 2 peptides further downregulated skin barrier genes, in particular the expression of genes involved in cell-matrix and cell-cell adhesion. Peptides also induced genes involved in hyperproliferation and caused disturbances in keratinocyte differentiation. Furthermore, inflammasome-relevant genes and IL18 were overexpressed, while KRT1 was downregulated. Our data suggest that Der p 2 peptides contribute to AD initiation and exacerbation by augmenting hallmark features of AD, such as skin inflammation, barrier disruption, and hyperplasia of keratinocytes.

Gene of the month: Cornulin

Cornulin (CRNN) gene encodes a 495 amino acid long protein and is located on chromosome 1q21.3. Primarily, it functions as the marker of differentiation. Initially, it was found to be specific for the squamous cells of oesophagus. However, later on, several studies have revealed the presence of Cornulin downregulation in various epithelial squamous cell carcinomas of the head and neck, oesophagus and cervix and clinically associated it with worsening of cancer and the poor prognosis. Cornulin levels also showed dysregulation in other diseases such as Eczema and Psoriasis. Besides the differentiation marker, it was identified to be involved in the stress response. The studies, in psoriasis and oesophageal squamous cell carcinoma, has elucidated that the dysregulation in the Cornulin is associated with the cell cycle events such as G1/S transition. However, the actual function of Cornulin is still yet to be explored in detail.

Filaggrin gene polymorphisms are associated with atopic dermatitis in women but not in men in the Caucasian population of Central Russia

Background and purpose

This study aimed to analyze the gender-specific association of the filaggrin (FLG) gene polymorphisms with atopic dermatitis (AD) in Caucasians from the central region of Russia.

Methods

The study sample consisted of 906 female (including 474 patients with AD and 432 controls) and 406 male (such as 226 patients with AD and 180 controls) participants. Genotyping of ten polymorphisms of the FLG gene was done. The logistic regression was used to analyze the associations. A total of 125 SNPs (seven AD-associated SNPs and 118 proxy SNPs, r²≥0.8) FLG gene were used for the in silico functional annotation analysis in the females.

Results

Significant associations were identified between seven SNPs of the FLG gene (rs12130219, rs61816761, rs558269137, rs12144049, rs3126085, rs471144, rs6661961) and AD in females: rs12144049 was associated independent individually (for allele C OR = 1.71, 95%Сl 1.19–2.46, р_perm = 0.004 and OR = 1.76, 95%Сl 1.18–2.63, р_perm = 0.006 according to the additive and dominant genetic models, respectively) and seven SNPs of the FLG gene within 14 haplotypes. Haplotype GGT [rs61816761-rs3126085-rs12144049] showed the strongest association (OR = 0.55, р_perm = 0.001). No association between the analyzed SNPs and AD was determined in the male group. The subsequent bioinformatic analysis predicted the SNPs of the FLG gene that possessed epigenetic and non-synonymous effects, were involved in the control of gene expression and alternative splicing of genes that contribute to AD pathophysiology.

Conclusion

Polymorphisms of the FLG gene are associated with AD in females but not in males in the Caucasian population of Central Russia.

Immunohistochemical expression of cornulin in lesional and perilesional skin of plaque psoriasis

BACKGROUND

Psoriasis is an immune-related disease with dermal inflammation and epidermal hyperplasia. Cornulin has a significant role in keratinocyte proliferation and stimulates inflammation in psoriasis.

AIM OF THE WORK

This work aims to evaluate Cornulin expression values in lesional and perilesional psoriatic skin compared with the control group's skin through immunohistochemistry.

METHODS

This case-control study included 30 cases with plaque psoriasis and another 30 as controls. Patient samples were collected, and immunohistochemical staining of Cornulin was conducted.

RESULTS

In the epidermis, there was a stepwise pattern of significant Cornulin overexpression in keratinocytes starting from controls (34.00 ± 23.65) to lesional (62.59 ± 23.93) passing through perilesional skin (36.52 ± 18.49) (p < 0.001). Moreover, there was also a stepwise pattern of the significance of Cornulin starting from 4 in controls (13.3% for both) to 28 lesional cases (93.3%) and 18 (60.0%) passing through 17 perilesional skin cases (56.7%) and 5 (16.7%) (p < 0.001 for both) for inflammatory cells and adnexa, respectively. A significant relationship between lesional epidermal Cornulin's strong intensity and a higher H-score and both hyperkeratosis and parakeratosis was found (p = 0.008 for both intensity and 0.028 for both H-scores).

CONCLUSION

Cornulin might be implicated in keratinocyte hyperproliferation and inflammation in plaque psoriasis and may be valuable as therapeutic target.

Cornulin Is Induced in Psoriasis Lesions and Promotes Keratinocyte Proliferation via Phosphoinositide 3-Kinase/Akt Pathways

Psoriasis is a chronic inflammatory skin disease characterized by abnormal proliferation of epidermal keratinocytes and infiltration of inflammatory cells. CRNN is a major component of the cornified cell envelope and implicated in several epithelial malignancies. Here, we show that CRNN expression was increased in the lesioned epidermis from the patients with psoriasis vulgaris and skin lesions from the imiquimod (IMQ)-treated mice. Expression of CRNN in cultured keratinocytes (HEKa and HaCaT) was also induced by M5, a mixture of five pro-inflammatory cytokines (i.e., IL-17A, IL-22, IL-1α, oncostatin M, and TNF-α). Lentiviral expression of CRNN increased cell proliferation by inducing cyclin D1. Conversely, knockdown of CRNN by small interfering RNA suppressed G1/S transition and attenuated the M5-induced proliferation. In addition, CRNN overexpression increased the phosphorylation and activation of phosphoinositide 3-kinase and Akt. Inactivation of the phosphoinositide 3-kinase and Akt pathways using small interfering RNA or selective inhibitors (LY294002 and MK2206) reduced the proliferative effects of CRNN. Furthermore, topical use of anti-psoriatic calcipotriol effectively decreased expression of CRNN, inhibited the Akt activation and improved the IMQ-stimulated psoriasis-like pathologies. Taken together, these results suggest that induced expression of CRNN may contribute to the pathogenesis of psoriasis.

Profound loss of esophageal tissue differentiation in patients with eosinophilic esophagitis

BACKGROUND

A key question in the allergy field is to understand how tissue-specific disease is manifested. Eosinophilic esophagitis (EoE) is an emerging tissue-specific allergic disease with an unclear pathogenesis.

OBJECTIVE

Herein we tested the hypothesis that a defect in tissue-specific esophageal genes is an integral part of EoE pathogenesis.

METHODS

We interrogated the pattern of expression of esophagus-specific signature genes derived from the Human Protein Atlas in the EoE transcriptome and in EPC2 esophageal epithelial cells. Western blotting and immunofluorescence were used for evaluating expression of esophageal proteins in biopsy specimens from control subjects and patients with active EoE. Whole-exome sequencing was performed to identify mutations in esophagus-specific genes.

RESULTS

We found that approximately 39% of the esophagus-specific transcripts were altered in patients with EoE, with approximately 90% being downregulated. The majority of transcriptional changes observed in esophagus-specific genes were reproduced in vitro in esophageal epithelial cells differentiated in the presence of IL-13. Functional enrichment analysis revealed keratinization and differentiation as the most affected biological processes and identified IL-1 cytokines and serine peptidase inhibitors as the most dysregulated esophagus-specific protein families in patients with EoE. Accordingly, biopsy specimens from patients with EoE evidenced a profound loss of tissue differentiation, decreased expression of keratin 4 (KRT4) and cornulin (CRNN), and increased expression of KRT5 and KRT14. Whole-exome sequencing of 33 unrelated patients with EoE revealed 39 rare mutations in 18 esophagus-specific differentially expressed genes.

CONCLUSIONS

A tissue-centered analysis has revealed a profound loss of esophageal tissue differentiation (identity) as an integral and specific part of the pathophysiology of EoE and implicated protease- and IL-1-related activities as putative central pathways in disease pathogenesis.

Deletion of Wiskott-Aldrich syndrome protein triggers Rac2 activity and increased cross-presentation by dendritic cells

Wiskott-Aldrich syndrome (WAS) is caused by loss-of-function mutations in the WASp gene. Decreased cellular responses in WASp-deficient cells have been interpreted to mean that WASp directly regulates these responses in WASp-sufficient cells. Here, we identify an exception to this concept and show that WASp-deficient dendritic cells have increased activation of Rac2 that support cross-presentation to CD8(+) T cells. Using two different skin pathology models, WASp-deficient mice show an accumulation of dendritic cells in the skin and increased expansion of IFNγ-producing CD8(+) T cells in the draining lymph node and spleen. Specific deletion of WASp in dendritic cells leads to marked expansion of CD8(+) T cells at the expense of CD4(+) T cells. WASp-deficient dendritic cells induce increased cross-presentation to CD8(+) T cells by activating Rac2 that maintains a near neutral pH of phagosomes. Our data reveals an intricate balance between activation of WASp and Rac2 signalling pathways in dendritic cells.

Storage Temperature Alters the Expression of Differentiation-Related Genes in Cultured Oral Keratinocytes

Purpose

Storage of cultured human oral keratinocytes (HOK) allows for transportation of cultured transplants to eye clinics worldwide. In a previous study, one-week storage of cultured HOK was found to be superior with regard to viability and morphology at 12°C compared to 4°C and 37°C. To understand more of how storage temperature affects cell phenotype, gene expression of HOK before and after storage at 4°C, 12°C, and 37°C was assessed.

Materials and Methods

Cultured HOK were stored in HEPES- and sodium bicarbonate-buffered Minimum Essential Medium at 4°C, 12°C, and 37°C for one week. Total RNA was isolated and the gene expression profile was determined using DNA microarrays and analyzed with Partek Genomics Suite software and Ingenuity Pathway Analysis. Differentially expressed genes (fold change > 1.5 and P < 0.05) were identified by one-way ANOVA. Key genes were validated using qPCR.

Results

Gene expression of cultures stored at 4°C and 12°C clustered close to the unstored control cultures. Cultures stored at 37°C displayed substantial change in gene expression compared to the other groups. In comparison with 12°C, 2,981 genes were differentially expressed at 37°C. In contrast, only 67 genes were differentially expressed between the unstored control and the cells stored at 12°C. The 12°C and 37°C culture groups differed most significantly with regard to the expression of differentiation markers. The Hedgehog signaling pathway was significantly downregulated at 37°C compared to 12°C.

Conclusion

HOK cultures stored at 37°C showed considerably larger changes in gene expression compared to unstored cells than cultured HOK stored at 4°C and 12°C. The changes observed at 37°C consisted of differentiation of the cells towards a squamous epithelium-specific phenotype. Storing cultured ocular surface transplants at 37°C is therefore not recommended. This is particularly interesting as 37°C is the standard incubation temperature used for cell culture.

Trichohyalin-like proteins have evolutionarily conserved roles in the morphogenesis of skin appendages

S100 fused-type proteins (SFTPs) such as filaggrin, trichohyalin, and cornulin are differentially expressed in cornifying keratinocytes of the epidermis and various skin appendages. To determine evolutionarily conserved, and thus presumably important, features of SFTPs, we characterized nonmammalian SFTPs and compared their amino acid sequences and expression patterns with those of mammalian SFTPs. We identified an ortholog of cornulin and a previously unknown SFTP, termed scaffoldin, in reptiles and birds, whereas filaggrin was confined to mammals. In contrast to mammalian SFTPs, both cornulin and scaffoldin of the chicken are expressed in the embryonic periderm. However, scaffoldin resembles mammalian trichohyalin with regard to its expression in the filiform papillae of the tongue and in the epithelium underneath the forming tips of the claws. Furthermore, scaffoldin is expressed in the epithelial sheath around growing feathers, reminiscent of trichohyalin expression in the inner root sheath of hair. The results of this study show that SFTP-positive epithelia function as scaffolds for the growth of diverse skin appendages such as claws, nails, hair, and feathers, indicating a common evolutionary origin.

dsRNA-induced changes in gene expression profiles of primary nasal and bronchial epithelial cells from patients with asthma, rhinitis and controls

Background

Rhinovirus infections are the most common cause of asthma exacerbations. The complex responses by airway epithelium to rhinovirus can be captured by gene expression profiling. We hypothesized that: a) upper and lower airway epithelium exhibit differential responses to double-stranded RNA (dsRNA), and b) that this is modulated by the presence of asthma and allergic rhinitis.

Objectives

Identification of dsRNA-induced gene expression profiles of primary nasal and bronchial epithelial cells from the same individuals and examining the impact of allergic rhinitis with and without concomitant allergic asthma on expression profiles.

Methods

This study had a cross-sectional design including 18 subjects: 6 patients with allergic asthma with concomitant rhinitis, 6 patients with allergic rhinitis, and 6 healthy controls. Comparing 6 subjects per group, the estimated false discovery rate was approximately 5%. RNA was extracted from isolated and cultured primary epithelial cells from nasal biopsies and bronchial brushings stimulated with dsRNA (poly(I:C)), and analyzed by microarray (Affymetrix U133+ PM Genechip Array). Data were analysed using R and the Bioconductor Limma package. Overrepresentation of gene ontology groups were captured by GeneSpring GX12.

Results

In total, 17 subjects completed the study successfully (6 allergic asthma with rhinitis, 5 allergic rhinitis, 6 healthy controls). dsRNA-stimulated upper and lower airway epithelium from asthma patients demonstrated significantly fewer induced genes, exhibiting reduced down-regulation of mitochondrial genes. The majority of genes related to viral responses appeared to be similarly induced in upper and lower airways in all groups. However, the induction of several interferon-related genes (IRF3, IFNAR1, IFNB1, IFNGR1, IL28B) was impaired in patients with asthma.

Conclusions

dsRNA differentially changes transcriptional profiles of primary nasal and bronchial epithelial cells from patients with allergic rhinitis with or without asthma and controls. Our data suggest that respiratory viruses affect mitochondrial genes, and we identified disease-specific genes that provide potential targets for drug development.

The human epidermal differentiation complex: cornified envelope precursors, S100 proteins and the 'fused genes' family

  The skin is essential for survival and protects our body against biological attacks, physical stress, chemical injury, water loss, ultraviolet radiation and immunological impairment. The epidermal barrier constitutes the primordial frontline of this defense established during terminal differentiation. During this complex process proliferating basal keratinocytes become suprabasally mitotically inactive and move through four epidermal layers (basal, spinous, granular and layer, stratum corneum) constantly adapting to the needs of the respective cell layer. As a result, squamous keratinocytes contain polymerized keratin intermediate filament bundles and a water-retaining matrix surrounded by the cross-linked cornified cell envelope (CE) with ceramide lipids attached on the outer surface. These cells are concomitantly insulated by intercellular lipid lamellae and hold together by corneodesmosmes. Many proteins essential for epidermal differentiation are encoded by genes clustered on chromosomal human region 1q21. These genes constitute the 'epidermal differentiation complex' (EDC), which is divided on the basis of common gene and protein structures, in three gene families: (i) CE precursors, (ii) S100A and (iii) S100 fused genes. EDC protein expression is regulated in a gene and tissue-specific manner by a pool of transcription factors. Among them, Klf4, Grhl3 and Arnt are essential, and their deletion in mice is lethal. The importance of the EDC is further reflected by human diseases: FLG mutations are the strongest risk factor for atopic dermatitis (AD) and for AD-associated asthma, and faulty CE formation caused by TG1 deficiency causes life-threatening lamellar ichthyosis. Here, we review the EDC genes and the progress in this field.

Inhibition of transcription factor specificity protein 1 alters the gene expression profile of keratinocytes leading to upregulation of kallikrein-related peptidases and thymic stromal lymphopoietin

Transcription factor specificity protein 1 (Sp1) is involved in diverse cellular functions. We recently found that Sp1 was significantly decreased in skin biopsy samples obtained from patients with atopic dermatitis (AD) and had an even greater reduction in AD patients with a history of eczema herpeticum. In the current study, we sought to better understand the role of Sp1 in skin biological processes by using a small-interfering RNA (siRNA) technique to knock down Sp1 gene expression in normal human keratinocytes (NHKs) and investigated the genome-wide gene expression profiling of Sp1-silenced NHKs. The gene arrays revealed that 53 genes had greater than 3-fold changes in the expression in Sp1-silenced NHKs as compared with scrambled siRNA-silenced cells. Strikingly, six kallikrein (KLK)-related peptidase genes, namely KLK5, KLK6, KLK7, KLK8, KLK10, and KLK12, were upregulated in NHKs following Sp1 silencing. Functionally, protease activity was significantly enhanced in Sp1-silenced keratinocytes as compared with scrambled siRNA-silenced keratinocytes. Moreover, thymic stromal lymphopoietin (TSLP), an epithelial-derived T(H)2-promoting cytokine, was induced in Sp1-silenced keratinocytes because of elevated KLK activity. These results indicate that Sp1 expression deficiency leads to abnormally increased KLK protease activity in keratinocytes and may contribute to T(H)2 immune responses in the skin by inducing TSLP.