H3K27Ac modification and gene expression in psoriasis

Inflammatory Memory in Epidermal Stem Cells - A New Strategy for Recurrent Inflammatory Skin Diseases

The ability of the skin to "remember" has been a potential mechanism for studying recurrent skin diseases. While it has been thought that the ability to retain past encounters is the prerogative of immune cells, it has recently been discovered that skin tissue stem cells can also take on this task. Epithelial stem cells undergoing inflammation retain their "memory" through epigenetic reprogramming and exhibit rapid epithelialization and epidermal proliferation upon secondary stimulation. This is a non-specific memory modality independent of conventional immune memory, in which histone modifications (acetylation and methylation) and specific transcription factors (AP-1 and STAT3) are involved in the establishment of inflammatory memories, and AIM2/Caspase-1/IL-1β mainly performs the rapid effects of memory. This finding is intriguing for addressing recurrent inflammatory skin diseases, which may explain the fixed-site recurrence of inflammatory skin diseases and develop new therapeutic strategies in the future. However, more research is still needed to decipher the mysteries of memory.

HDAC/H3K27ac-mediated transcription of NDUFA3 exerts protective effects on high glucose-treated human nucleus pulposus cells through improving mitochondrial function

Diabetes mellitus (DM) is a well-documented risk factor of intervertebral disc degeneration (IVDD). The current study was aimed to clarify the effects and mechanisms of NADH: ubiquinone oxidoreductase subunit A3 (NDUFA3) in human nucleus pulposus cells (HNPCs) exposed to high glucose. NDUFA3 was overexpressed in HNPCs via lenti-virus transduction, which were co-treated with high glucose and rotenone (a mitochondrial complex I inhibitor) for 48 h. Cell activities were assessed for cell viability, cell apoptosis, reactive oxygen species (ROS) production, mitochondrial membrane potential (MMP) ratio, oxygen consumption rate (OCR) and mitochondrial complexes I activities. High glucose decreased cell viability, increased apoptotic cells, increased ROS production, decreased MMP levels and OCR values in HNPCs in a dose-dependent manner. Rotenone co-treatment augmented the high glucose-induced injuries on cell viability, apoptosis, ROS production and mitochondrial function. NDUFA3 overexpression counteracted the high glucose-induced injuries in HNPCs. HDAC/H3K27ac mechanism was involved in regulating NDUFA3 transcription. NDUFA3 knockdown decreased cell viability and increased apoptotic cells, which were reversed by ROS scavenger N-acetylcysteine. HDAC/H3K27ac-mediated transcription of NDUFA3 protects HNPCs against high glucose-induced injuries through suppressing cell apoptosis, eliminating ROS, improving mitochondrial function and oxidative phosphorylation. This study sheds light on candidate therapeutic targets and deepens the understanding of molecular mechanisms behind DM-induced IVDD.

Histone modification in psoriasis: Molecular mechanisms and potential therapeutic targets

Psoriasis is an immune-mediated, inflammatory disease. Genetic and environmental elements are involved in the nosogenesis of this illness. Epigenetic inheritance serves as the connection between genetic and environmental factors. Histone modification, an epigenetic regulatory mechanism, is implicated in the development of numerous diseases. The basic function of histone modification is to regulate cellular functions by modifying gene expression. Modulation of histone modification, such as regulation of enzymes pertinent to histone modification, can be an alternative approach for treating some diseases, including psoriasis. Herein, we reviewed the regulatory mechanisms and biological effects of histone modifications and their roles in the pathogenesis of psoriasis.

H3K27ac acts as a molecular switch for doxorubicin-induced activation of cardiotoxic genes

BACKGROUND

Doxorubicin (Dox) is an effective chemotherapeutic drug for various cancers, but its clinical application is limited by severe cardiotoxicity. Dox treatment can transcriptionally activate multiple cardiotoxicity-associated genes in cardiomyocytes, the mechanisms underlying this global gene activation remain poorly understood.

METHODS AND RESULTS

Herein, we integrated data from animal models, CUT&Tag and RNA-seq after Dox treatment, and discovered that the level of H3K27ac (a histone modification associated with gene activation) significantly increased in cardiomyocytes following Dox treatment. C646, an inhibitor of histone acetyltransferase, reversed Dox-induced H3K27ac accumulation in cardiomyocytes, which subsequently prevented the increase of Dox-induced DNA damage and apoptosis. Furthermore, C646 alleviated cardiac dysfunction in Dox-treated mice by restoring ejection fraction and reversing fractional shortening percentages. Additionally, Dox treatment increased H3K27ac deposition at the promoters of multiple cardiotoxic genes including Bax, Fas and Bnip3, resulting in their up-regulation. Moreover, the deposition of H3K27ac at cardiotoxicity-related genes exhibited a broad feature across the genome. Based on the deposition of H3K27ac and mRNA expression levels, several potential genes that might contribute to Dox-induced cardiotoxicity were predicted. Finally, the up-regulation of H3K27ac-regulated cardiotoxic genes upon Dox treatment is conservative across species.

CONCLUSIONS

Taken together, Dox-induced epigenetic modification, specifically H3K27ac, acts as a molecular switch for the activation of robust cardiotoxicity-related genes, leading to cardiomyocyte death and cardiac dysfunction. These findings provide new insights into the relationship between Dox-induced cardiotoxicity and epigenetic regulation, and identify H3K27ac as a potential target for the prevention and treatment of Dox-induced cardiotoxicity.

Noval advance of histone modification in inflammatory skin diseases and related treatment methods

Inflammatory skin diseases are a group of diseases caused by the disruption of skin tissue due to immune system disorders. Histone modification plays a pivotal role in the pathogenesis and treatment of chronic inflammatory skin diseases, encompassing a wide range of conditions, including psoriasis, atopic dermatitis, lupus, systemic sclerosis, contact dermatitis, lichen planus, and alopecia areata. Analyzing histone modification as a significant epigenetic regulatory approach holds great promise for advancing our understanding and managing these complex disorders. Additionally, therapeutic interventions targeting histone modifications have emerged as promising strategies for effectively managing inflammatory skin disorders. This comprehensive review provides an overview of the diverse types of histone modification. We discuss the intricate association between histone modification and prevalent chronic inflammatory skin diseases. We also review current and potential therapeutic approaches that revolve around modulating histone modifications. Finally, we investigated the prospects of research on histone modifications in the context of chronic inflammatory skin diseases, paving the way for innovative therapeutic interventions and improved patient outcomes.

The role of enhancers in psoriasis and atopic dermatitis

Regulatory elements, particularly enhancers, play a crucial role in disease susceptibility and progression. Enhancers are DNA sequences that activate gene expression and can be affected by epigenetic modifications, interactions with transcription factors (TFs) or changes to the enhancer DNA sequence itself. Altered enhancer activity impacts gene expression and contributes to disease. In this review, we define enhancers and the experimental techniques used to identify and characterize them. We also discuss recent studies that examine how enhancers contribute to atopic dermatitis (AD) and psoriasis. Articles in the PubMed database were identified (from 1 January 2010 to 28 February 2023) that were relevant to enhancer variants, enhancer-associated TFs and enhancer histone modifications in psoriasis or AD. Most enhancers associated with these conditions regulate genes affecting epidermal homeostasis or immune function. These discoveries present potential therapeutic targets to complement existing treatment options for AD and psoriasis.

G-quadruplex is critical to epigenetic activation of the lncRNA HOTAIR in cancer cells

The cancer-promoting lncRNA HOTAIR has multiple isoforms. Which isoform of HOTAIR accounts for its expression and functions in cancer is unknown. Unlike HOTAIR's canonical intergenic isoform NR_003716 (HOTAIR-C), the novel isoform NR_047517 (HOTAIR-N) forms an overlapping antisense transcription locus with HOXC11. We identified HOTAIR-N as the dominant isoform that regulates the gene expression programs and networks for cell proliferation, survival, and death in cancer cells. The CpG island in the HOTAIR-N promoter was marked with epigenetic markers for active transcription. We identified a G-quadruplex (G4) motif rich region in the HOTAIR-N CpG island. Our findings indicate that G4s in HOTAIR-N CpG island is critical for expression of HOTAIR-N in cancer cells. Disruption of G4 may represent a novel therapeutic approach for cancer. The transcriptomes regulated by HOTAIR-N and Bloom in cancer cells as provided herein are important resources for the exploration of lncRNA, DNA helicases, and G4 in cancer.

Exploration of the biomarkers of comorbidity of psoriasis with inflammatory bowel disease and their association with immune infiltration

BACKGROUND

There was evidence that significant bidirectional associations between psoriasis and inflammatory bowel diseases (IBDs), which influences management strategy of the patients, so the investigation on the mechanisms by which these two diseases co-occur is important.

METHODS

The Gene Expression Omnibus (GEO) database was used to download gene expression profiles of psoriasis and IBD. The differentially expressed genes (DEGs) between disease and health control groups for each data set were calculated, and Venn diagram was used to obtain for intersection. We performed Gene ontology (GO) and Kyoto Encyclopedia of Genes and Genomes (KEGG) enrichment analysis on the intersection, followed by developing a protein-protein interaction network and module construction, and identified hub genes by cytoHubba. Thereafter, least absolute shrinkage and selection operator algorithms was used to identify the co-biomarkers of psoriasis and IBD from the top 50 hub genes. The biomarkers were used to construct a screening model, the discriminatory capacity of which was verified by receiver operating characteristic (ROC) curves. CIBERSORT algorithm was utilized to estimate the compositional patterns of immune cell infiltration in biomarkers of psoriasis and IBD. Spearman rank correlation analysis was used to further evaluate the correlation between the identified biomarkers and immune cells.

RESULTS

A total of 271 shared DEGs were screened. The GO and KEGG enrichment analysis indicated that the shared DEGs were mainly enriched in response to lipopolysaccharide, secretory granule lumen, cytokine activity, and interleukin (IL)-17 signaling pathway. Fifty genes such as IL1B, IL6, were identified as hub genes, based on which, FOS, IFI44, MMP9, MNDA, PTGS2, S100A9, and STAT1 were identified as biomarkers of psoriasis. CCL20, CD274, CTGF, CXCL1, CXCL10, CXCL2, CXCL9, FCGR3B, FOS, GBP1, GZMB, IFI27, IFI6, IL1RN, ISG15, ISG20, LCN2, LILRB2, MMP12, MMP7, S100A8, TLR8, and TNFSF13B were identified as biomarkers of IBD. FOS was the common biomarker of psoriasis and IBD. Screening models were validated in the validation data set (Psoriasis: area under the curve (AUC) = 1.000, IBD: AUC = 0.870). Immunocyte infiltration analysis showed the macrophages cells, mast cells resting, and T cells CD4 memory activated have the common characteristics in psoriasis and IBD.

CONCLUSIONS

FOS may play a key role in the occurrence and development of psoriasis complicated with IBD and macrophages cells may be an entrance for treating this comorbidity.

Pro-inflammatory cytokine IL-6 regulates LMO4 expression in psoriatic keratinocytes via AKT/STAT3 pathway

The transcription factor LIM-only protein 4 (LMO4) is overexpressed in the psoriatic epidermis and regulates keratinocyte proliferation and differentiation. High LMO4 expression levels are induced by interleukin-23 (IL-23) to activate the AKT/STAT3 signaling pathway. Interleukin-6 (IL-6) is mainly involved in regulating T cell functions and development in patients with psoriasis. However, whether LMO4 expression is regulated by IL-6 remains unclear. Therefore, the purpose of this study is to explore the role and molecular mechanisms of IL-6 in regulating LMO4 expression. The interleukin-6 (IL-6) levels in human plasma were determined using a chemiluminescence immunoassay system. A psoriasis-like mouse model was established using imiquimod induction. Epidermal keratinocytes (HaCaT) were cultured in defined keratinocyte-serum-free medium and stimulated by IL-6 alone or with inhibitors. The proteins of interest were detected using western blot analysis, immunofluorescence, and immunohistochemistry. The 5-ethynyl-2'-deoxyuridine assay was used to detect cell proliferation. The results revealed that IL-6 levels were markedly increased in the plasma of patients with psoriasis, compared to healthy control. The high expression of LMO4 was consistent with high levels of IL-6, p-AKT, and p-STAT3 in the lesions of both psoriasis patients and imiquimod-induced psoriasis-like mice. IL-6 activates the AKT/STAT3 signaling pathway, followed by LMO4 high-expression in HaCaT cells. IL-6 induces HaCaT proliferation and differentiation via AKT/STAT3 signaling pathway activation. We think that the high expression of LMO4 in psoriatic keratinocytes requires IL-6 to activate the AKT/STAT3 signaling pathway and leads to epidermal keratinocytes abnormal proliferation and differentiation.

Histone and Histone Acetylation-Related Alterations of Gene Expression in Uninvolved Psoriatic Skin and Their Effects on Cell Proliferation, Differentiation, and Immune Responses

Psoriasis is a chronic immune-mediated skin disease in which the symptom-free, uninvolved skin carries alterations in gene expression, serving as a basis for lesion formation. Histones and histone acetylation-related processes are key regulators of gene expression, controlling cell proliferation and immune responses. Dysregulation of these processes is likely to play an important role in the pathogenesis of psoriasis. To gain a complete overview of these potential alterations, we performed a meta-analysis of a psoriatic uninvolved skin dataset containing differentially expressed transcripts from nearly 300 individuals and screened for histones and histone acetylation-related molecules. We identified altered expression of the replication-dependent histones HIST2H2AA3 and HIST2H4A and the replication-independent histones H2AFY, H2AFZ, and H3F3A/B. Eight histone chaperones were also identified. Among the histone acetyltransferases, ELP3 and KAT5 and members of the ATAC, NSL, and SAGA acetyltransferase complexes are affected in uninvolved skin. Histone deacetylation-related alterations were found to affect eight HDACs and members of the NCOR/SMRT, NURD, SIN3, and SHIP HDAC complexes. In this article, we discuss how histone and histone acetylation-related expression changes may affect proliferation and differentiation, as well as innate, macrophage-mediated, and T cell-mediated pro- and anti-inflammatory responses, which are known to play a central role in the development of psoriasis.

Ovulatory signal-triggered chromatin remodeling in ovarian granulosa cells by HDAC2 phosphorylation activation-mediated histone deacetylation

BACKGROUND

Epigenetic reprogramming is involved in luteinizing hormone (LH)-induced ovulation; however, the underlying mechanisms are largely unknown.

RESULTS

We here observed a rapid histone deacetylation process between two waves of active transcription mediated by the follicle-stimulating hormone (FSH) and the LH congener human chorionic gonadotropin (hCG), respectively. Analysis of the genome-wide H3K27Ac distribution in hCG-treated granulosa cells revealed that a rapid wave of genome-wide histone deacetylation remodels the chromatin, followed by the establishment of specific histone acetylation for ovulation. HDAC2 phosphorylation activation coincides with histone deacetylation in mouse preovulatory follicles. When HDAC2 was silenced or inhibited, histone acetylation was retained, leading to reduced gene transcription, retarded cumulus expansion, and ovulation defect. HDAC2 phosphorylation was associated with CK2α nuclear translocation, and inhibition of CK2α attenuated HDAC2 phosphorylation, retarded H3K27 deacetylation, and inactivated the ERK1/2 signaling cascade.

CONCLUSIONS

This study demonstrates that the ovulatory signal erases histone acetylation through activation of CK2α-mediated HDAC2 phosphorylation in granulosa cells, which is an essential prerequisite for subsequent successful ovulation.

The p300/CBP Inhibitor A485 Normalizes Psoriatic Fibroblast Gene Expression In Vitro and Reduces Psoriasis-Like Skin Inflammation In Vivo

Psoriasis is a chronic inflammatory skin disease that often recurs at the same locations, indicating potential epigenetic changes in lesional skin cells. In this study, we discovered that fibroblasts isolated from psoriatic skin lesions retain an abnormal phenotype even after several passages in culture. Transcriptomic profiling revealed the upregulation of several genes, including the extra domain A splice variant of fibronectin and ITGA4 in psoriatic fibroblasts. A phenotypic library screening of small-molecule epigenetic modifier drugs revealed that selective CBP/p300 inhibitors were able to rescue the psoriatic fibroblast phenotype, reducing the expression levels of extra domain A splice variant of fibronectin and ITGA4. In the imiquimod-induced mouse model of psoriasis-like skin inflammation, systemic treatment with A485, a potent CBP/p300 blocker, significantly reduced skin inflammation, immune cell recruitment, and inflammatory cytokine production. Our findings indicate that epigenetic reprogramming might represent a new approach for the treatment and/or prevention of relapses of psoriasis.

KMT2C Induced by FABP5P3 Aggravates Keratinocyte Hyperproliferation and Psoriasiform Skin Inflammation by Upregulating the Transcription of PIK3R3

The extensive involvement of lysine methyltransferase 2C (KMT2C) in the inflammatory response is well-documented. However, little is known about the role of KMT2C in psoriasis. We identified that KMT2C was significantly upregulated in the epidermis of psoriatic skin lesions and the psoriasiform cell model. KMT2C knockdown diminished keratinocyte proliferation and the secretion of IL-6, IL-8, CCL20, and S100A9 in vitro and in vivo. In psoriasiform keratinocytes, KMT2C promoted the transcription of PIK3R3 by regulating the enrichment of histone H3 lysine 4 trimethylation at the PIK3R3 promoter and histone 3 lysine 4 monomethylation at the enhancer. The PIK3R3/protein kinase B/NF-κB pathway is a vital step in KMT2C-mediated alleviation of cytokine-primed inflammation. The long noncoding RNA FABP5P3 sustained KMT2C mRNA stability by recruiting human antigen R. Furthermore, inhibition of KMT2C attenuated epidermal hyperplasia and skin inflammation in mice with psoriasis. Taken together, our findings indicated a link between KMT2C and psoriasis and opened the possibility of using KMT2C as a potential therapeutic target for psoriasis treatment.

Contribution of the Environment, Epigenetic Mechanisms and Non-Coding RNAs in Psoriasis

Despite the increasing research and clinical interest in the predisposition of psoriasis, a chronic inflammatory skin disease, the multitude of genetic and environmental factors involved in its pathogenesis remain unclear. This complexity is further exacerbated by the several cell types that are implicated in Psoriasis’s progression, including keratinocytes, melanocytes and various immune cell types. The observed interactions between the genetic substrate and the environment lead to epigenetic alterations that directly or indirectly affect gene expression. Changes in DNA methylation and histone modifications that alter DNA-binding site accessibility, as well as non-coding RNAs implicated in the post-transcriptional regulation, are mechanisms of gene transcriptional activity modification and therefore affect the pathways involved in the pathogenesis of Psoriasis. In this review, we summarize the research conducted on the environmental factors contributing to the disease onset, epigenetic modifications and non-coding RNAs exhibiting deregulation in Psoriasis, and we further categorize them based on the under-study cell types. We also assess the recent literature considering therapeutic applications targeting molecules that compromise the epigenome, as a way to suppress the inflammatory cutaneous cascade.

Role of Histone Post-Translational Modifications in Inflammatory Diseases

Inflammation is a defensive reaction for external stimuli to the human body and generally accompanied by immune responses, which is associated with multiple diseases such as atherosclerosis, type 2 diabetes, Alzheimer’s disease, psoriasis, asthma, chronic lung diseases, inflammatory bowel disease, and multiple virus-associated diseases. Epigenetic mechanisms have been demonstrated to play a key role in the regulation of inflammation. Common epigenetic regulations are DNA methylation, histone modifications, and non-coding RNA expression; among these, histone modifications embrace various post-modifications including acetylation, methylation, phosphorylation, ubiquitination, and ADP ribosylation. This review focuses on the significant role of histone modifications in the progression of inflammatory diseases, providing the potential target for clinical therapy of inflammation-associated diseases.