MicroRNA-122 promotes apoptosis of keratinocytes in oral lichen planus through suppressing VDR expression

Association between Vitamin D Receptor Polymorphism and Susceptibility to Oral Lichen Planus and Oral Squamous Cell Carcinoma

Introduction

Oral squamous cell carcinomas (OSCC) comprise 90-95% of oral cancers. Early diagnosis improved the survival rate of OSCC patients to 80-90%. Oral lichen planus (OLP) is a chorionic inflammatory disease with malignancy potential. The vitamin D receptor (VDR) plays a critical role in the pathogenesis of oral cancer. This study aimed to determine the association between VDR rs7975232 (Apa I) polymorphism and potential susceptibility to OLP and OSCC risks.

Materials and Methods

In this prospective case-control study, a total of 120 blood samples were obtained from OSCC patients (n=29), OLP (n=50), and controls (n=40). VDR rs7975232 polymorphism was studied using the Polymerase Chain Reaction Restriction Fragment Length Polymorphism (PCR-RFLP) method. Statistical analysis was performed with SPSS Version 23 software. Data were expressed as means ± standard deviation (SD). Age, sex, allelic frequency, and genotyping were compared using the chi-square test. A p-value of less than 0.05 was regarded as statistically significant. The disease risk was estimated by Odds ratio (OR) with a 95% confidence interval.

Results

A significant age difference was observed between the controls and the OSCC group (p=0.001). A significant difference was observed in Aa and aa genotypes compared with AA between OSCCs and controls. Moreover, dominant (p<0.001), additive (p<0.001), and allelic (p=0.001) models were different between groups.

Conclusion

There was a positive association between rs7975232 VDR polymorphism and susceptibility to OSCC. More experimental evidence must reveal the possible association between rs7975232 and the risk of OLP in a larger cohort.

Polymorphism but not methylation status in the vitamin D receptor gene contributes to oral mucositis in children

OBJECTIVE

To investigate the relationship between the polymorphisms rs1544410 (BsmI), rs2228570 (FokI) and rs731236 (TaqI) and DNA methylation status in the VDR gene (vitamin D receptor) with oral mucositis (OM) in oncopaediatric patients treated with methotrexate (MTX®).

METHODS

The population comprised healthy patients with haematological malignancies aged between 5 and 19 years. An evaluation of oral conditions was performed using the Oral Assessment Guide. Demographic, clinical, biochemical and haematological data were obtained from medical records. Genomic DNA from oral mucosal cells was used for the analysis of polymorphisms (n = 102) (PCR-restriction fragment length polymorphism) and DNA methylation (n = 81) (methylation-specific PCR).

RESULTS

Males predominated (57.8%), and the mean age was 10.3 years (±4.7). OM affected 84.3% of patients, of which 53.1% developed severe oral mucositis (SOM). Patients with OM had lower platelet and leukocyte counts (p < 0.05). The G allele of rs1544410 (p = 0.040) and the CT genotype of rs2228570 polymorphisms were associated with SOM (p = 0.038). A partially methylated status in the VDR promoter was found in all patients.

CONCLUSION

OM is associated with lower leukocyte and platelet counts. SOM is associated with the rs1544410 and rs2228570 polymorphisms. The methylation status of the VDR is not associated with inflammation or exposure to MTX®.

The role and mechanism of action of microRNA-122 in cancer: Focusing on the liver

microRNA-122 (miR-122) is a highly conserved microRNA that is predominantly expressed in the liver and plays a critical role in the regulation of liver metabolism. Recent studies have shown that miR-122 is involved in the pathogenesis of various types of cancer, particularly liver cancer. In this sense, The current findings highlighted the potential role of miR-122 in regulating many vital processes in cancer pathophysiology, including apoptosis, signaling pathway, cell metabolism, immune system response, migration, and invasion. These results imply that miR-122, which has been extensively studied for its biological functions and potential therapeutic applications, acts as a tumor suppressor or oncogene in cancer development. We first provide an overview and summary of the physiological function and mode of action of miR-122 in liver cancer. We will examine the various signaling pathways and molecular mechanisms through which miR-122 exerts its effects on cancer cells, including the regulation of oncogenic and tumor suppressor genes, the modulation of cell proliferation and apoptosis, and the regulation of metastasis. Most importantly, we will also discuss the potential diagnostic and therapeutic applications of miR-122 in cancer, including the development of miRNA-based biomarkers for cancer diagnosis and prognosis, and the potential use of miR-122 as a therapeutic target for cancer treatment.

The PI3K-Akt-mTOR and Associated Signaling Pathways as Molecular Drivers of Immune-Mediated Inflammatory Skin Diseases: Update on Therapeutic Strategy Using Natural and Synthetic Compounds

The dysregulated phosphatidylinositol-3-kinase (PI3K)-Akt-mammalian target of rapamycin (mTOR) signaling pathway has been implicated in various immune-mediated inflammatory and hyperproliferative dermatoses such as acne, atopic dermatitis, alopecia, psoriasis, wounds, and vitiligo, and is associated with poor treatment outcomes. Improved comprehension of the consequences of the dysregulated PI3K/Akt/mTOR pathway in patients with inflammatory dermatoses has resulted in the development of novel therapeutic approaches. Nonetheless, more studies are necessary to validate the regulatory role of this pathway and to create more effective preventive and treatment methods for a wide range of inflammatory skin diseases. Several studies have revealed that certain natural products and synthetic compounds can obstruct the expression/activity of PI3K/Akt/mTOR, underscoring their potential in managing common and persistent skin inflammatory disorders. This review summarizes recent advances in understanding the role of the activated PI3K/Akt/mTOR pathway and associated components in immune-mediated inflammatory dermatoses and discusses the potential of bioactive natural products, synthetic scaffolds, and biologic agents in their prevention and treatment. However, further research is necessary to validate the regulatory role of this pathway and develop more effective therapies for inflammatory skin disorders.

Comprehensive Insight into Lichen Planus Immunopathogenesis

Lichen planus is a chronic disease affecting the skin, appendages, and mucous membranes. A cutaneous lichen planus is a rare disease occurring in less than 1% of the general population, while oral illness is up to five times more prevalent; still, both forms equally impair the patient's quality of life. The etiology of lichen planus is not entirely understood. Yet, immune-mediated mechanisms have been recognized since environmental factors such as hepatitis virus infection, mechanical trauma, psychological stress, or microbiome changes can trigger the disease in genetically susceptible individuals. According to current understanding, lichen planus immunopathogenesis is caused by cell-mediated cytotoxicity, particularly cytotoxic T lymphocytes, whose activity is further influenced by Th1 and IL-23/Th-17 axis. However, other immunocytes and inflammatory pathways complement these mechanisms. This paper presents a comprehensive insight into the actual knowledge about lichen planus, with the causal genetic and environmental factors being discussed, the immunopathogenesis described, and the principal effectors of its inflammatory circuits identified.

The Functional Mechanism of MicroRNA in Oral Lichen Planus

Non-coding RNAs (ncRNAs) are transcribed from the genomes of mammals and other complex organisms, and many of them are alternately spliced and processed into smaller products. Types of ncRNAs include microRNAs (miRNAs), circular RNAs, and long ncRNAs. miRNAs are about 21 nucleotides long and form a broad class of post-transcriptional regulators of gene expression that affect numerous developmental and physiological processes in eukaryotes. They usually act as negative regulators of mRNA expression through complementary binding sequences in the 3’-UTR of the target mRNA, leading to translation inhibition and target degradation. In recent years, the importance of ncRNA in oral lichen planus (OLP), particularly miRNA, has attracted extensive attention. However, the biological functions of miRNAs and their mechanisms in OLP are still unclear. In this review, we discuss the role and function of miRNAs in OLP, and we also describe their potential functional roles as biomarkers for the diagnosis of OLP. MiRNAs are promising new therapeutic targets, but more work is needed to understand their biological functions.

1,25(OH)2 D3 blocks IFNβ production through regulating STING in epithelial layer of oral lichen planus

Stimulator of interferon genes (STING) is reported to exert vital functions in inflammatory responses and autoimmune diseases. Nevertheless, the status and roles of STING in oral lichen planus (OLP) remain elusive. Here, we state that STING and its downstream cytokine interferon‐β (IFNβ) expression is boosted in the oral keratinocytes from patients suffering OLP in comparison with those from healthy participants. Mechanistically, transcription factor GATA‐binding protein 1 (GATA1) which is highly increased in diseased samples specifically interacts with its element in the promoter of STING to enhance STING transcripts. 1,25(OH)₂D₃, the active form of vitamin D, is capable of restricting STING and IFNβ increases in oral keratinocyte models resembling OLP in vitro. Moreover, there is a negative correlation between vitamin D receptor (VDR) and STING or IFNβ in human samples. Using plasmids and small interfering RNA transfection technologies, we find 1,25(OH)₂D₃ regulates STING and IFNβ through a mechanism controlled by the hypoxia‐inducible factor‐1α (HIF‐1α)‐GATA1 axis. Collectively, our findings unveil that 1,25(OH)₂D₃ lowers STING and IFNβ overexpression in the context of OLP.

MicroRNA-122 promotes apoptosis of keratinocytes in oral lichen planus through suppressing VDR expression

MicroRNA‐122 (miR‐122) is known to be up‐regulated by inflammation to exert a variety of biological functions in hepatocellular carcinoma (HCC)‐derived human cell lines. Vitamin D receptor (VDR) is reported to regulate excessive oral keratinocytes apoptosis which compromises oral epithelial barrier in oral lichen planus (OLP). Although many studies have suggested that miR‐122 is capable of regulating cell apoptosis, its effects on the development of OLP and VDR expression are still unclear. Herein, we demonstrate that miR‐122 expression is increased in the epithelial layer of OLP. Mechanically, transcription factor nuclear factor‐κB (NF‐κB) selectively binds with κB element in the promoter of miR‐122 to accelerate gene transcription. The up‐regulation of miR‐122 induces cell apoptosis in human oral keratinocytes (HOKs) by targeting VDR mRNA. In VDR knockout oral keratinocytes, miR‐122 fails to improve caspase 3 activity and cleaved caspase 3 and poly(ADP‐ribose) polymerase (PARP) levels. Moreover, VDR overexpression is able to reverse lipopolysaccharide (LPS)‐ or activated CD4+ T cell–induced miR‐122 up‐regulation and ameliorate miR‐122‐stimulated caspase 3 activity. Collectively, our results suggest that miR‐122 promotes oral keratinocytes apoptosis in OLP through decreasing VDR expression.