Transcription factors Krüppel-like factor 4 and paired box 5 regulate the expression of the Grainyhead-like genes

Integrative Transcriptomic Analysis of Peripheral Blood Monocytes in Systemic Sclerosis and Shared Pathogenic Pathways in Autoimmune Diseases

BACKGROUND

Systemic sclerosis (SSc) is an autoimmune disease (AD), that receives less attention compared to rheumatoid arthritis (RA), systemic lupus erythematosus (SLE), and primary Sjögren's syndrome (pSS). This study aims to analyze transcriptional profiles and immune cell composition in peripheral blood mononuclear cells (PBMC) from SSc patients compared to other ADs.

METHODS

RNA-seq data from 119 untreated patients (eight with SSc, 42 with RA, 41 with pSS, 28 with SLE) and 20 healthy controls were analyzed. Bioinformatics tools were employed to identify differentially expressed genes (DEGs), biological functions and immune cell profiles unique to SSc and shared with other ADs.

RESULTS

1,148 DEGs were found in SSc, with upregulated genes associated with megakaryocyte processes and downregulated genes associated with neutrophil function and immune response. DEGs, including ALDH1A1 and MEGF9, were associated with neutropenia. Upregulated transcription factors (TFs) were linked to embryonic hematopoiesis and downregulated TFs were involved in leukocyte differentiation and immune regulation. Comparative analysis with other ADs revealed common pathogenic pathways, emphasizing megakaryocyte proliferation. Neutrophils count was significantly decreased in ADs (p <0.001) compared to healthy controls. Comparative analysis highlighted common pathways, particularly in megakaryocyte proliferation, and unique genes (MEGF9, MMP8, and KRT family members) in SSc, suggesting roles in neutrophil function, skin integrity, and fibrosis.

CONCLUSIONS

This study identifies dysregulated gene expression (KRT and MMP8) associated with neutrophil function and increased megakaryocytes in SSc, highlighting common patterns across autoimmune diseases. These findings offer new insights into the potential pathogenesis of SSc, and help to explore new targets for the treatment.

ZNF217 Mediates Transcriptional Activation of GRHL3 to Regulate SLC22A31 and Promote Malignant Progression in Thyroid Cancer

The incidence of thyroid cancer (THCA) has increased worldwide during the past 40 years. However, an understanding of the mechanisms and major transcription factors involved in THCA is insufficient to identify therapeutic targets against THCA. To reveal such mechanisms, we conducted bioinformatics analyses to assess the differential expression in human THCA sample and normal tissue sample, leading us to focus on the function of the ZNF217/GRHL3/ SLC22A31 axis in mediating biological activity in THCA. The genes of interest were interfered with lentiviral vectors, and transfection efficiency was verified using RT-qPCR. ZNF217, GRHL3, and SLC22A31 were abundantly expressed in THCA tissues or cells. Knockdown of GRHL3, ZNF217, or SLC22A31 all significantly curtailed the malignant biological behavior of THCA cells. ZNF217 promoted GRHL3 expression through transcriptional activation, thereby increasing the transcription of SLC22A31. Ectopic expression of GRHL3 or SLC22A31 abated the suppressing impact of ZNF217 or GRHL3 knockdown on the biological activity of THCA cells. Collectively, our results demonstrated that ZNF217 acted as an activator of GRHL3, thereby promoting the expression of SLC22A31 and the malignant activity of THCA cells.

Vitamin D Receptor Regulates the Expression of the Grainyhead-Like 1 Gene

Vitamin D plays an important pleiotropic role in maintaining global homeostasis of the human body. Its functions go far beyond skeletal health, playing a crucial role in a plethora of cellular functions, as well as in extraskeletal health, ensuring the proper functioning of multiple human organs, including the skin. Genes from the Grainyhead-like (GRHL) family code for transcription factors necessary for the development and maintenance of various epithelia. Even though they are involved in many processes regulated by vitamin D, a direct link between vitamin D-mediated cellular pathways and GRHL genes has never been described. We employed various bioinformatic methods, quantitative real-time PCR, chromatin immunoprecipitation, reporter gene assays, and calcitriol treatments to investigate this issue. We report that the vitamin D receptor (VDR) binds to a regulatory region of the Grainyhead-like 1 (GRHL1) gene and regulates its expression. Ectopic expression of VDR and treatment with calcitriol alters the expression of the GRHL1 gene. The evidence presented here indicates a role of VDR in the regulation of expression of GRHL1 and correspondingly a role of GRHL1 in mediating the actions of vitamin D.

Loss-of-function variants in KLF4 underlie autosomal dominant palmoplantar keratoderma

PURPOSE

Palmoplantar keratodermas (PPKs) form a group of disorders characterized by thickening of palm and sole skin. Over the past 2 decades, many types of inherited PPKs have been found to result from abnormal expression, processing, or function of adhesion proteins.

METHODS

We used exome and direct sequencing to detect causative pathogenic variants. Functional analysis of these variants was conducted using reverse transcription quantitative polymerase chain reaction, immunofluorescence confocal microscopy, immunoblotting, a promoter reporter assay, and chromatin immunoprecipitation.

RESULTS

We identified 2 heterozygous variants (c.1226A>G and c.633_634dupGT) in KLF4 in 3 individuals from 2 different unrelated families affected by a dominant form of PPK. Immunofluorescence staining for a number of functional markers revealed reduced epidermal DSG1 expression in patients harboring heterozygous KLF4 variants. Accordingly, human keratinocytes either transfected with constructs expressing these variants or downregulated for KLF4 displayed reduced DSG1 expression, which in turn has previously been found to be associated with PPK. A chromatin immunoprecipitation assay confirmed direct binding of KLF4 to the DSG1 promoter region. The ability of mutant KLF4 to transactivate the DSG1 promoter was significantly decreased when compared with wild-type KLF4.

CONCLUSION

Loss-of-function variants in KLF4 cause a novel form of dominant PPK and show its importance in the regulation of epidermal differentiation.