CircRNA_09505 aggravates inflammation and joint damage in collagen-induced arthritis mice via miR-6089/AKT1/NF-κB axis

Integrating clinical data mining, network analysis and experimental validation reveal the anti-inflammatory mechanism of Huangqin Qingre Chubi Capsule in rheumatoid arthritis treatment

ETHNOPHARMACOLOGICAL RELEVANCE

Huangqin Qingre Chubi Capsule (HQC) is a Chinese medicinal compound used for the treatment of damp-heat pattern rheumatism, guided by the traditional Chinese medicine syndrome differentiation practice. HQC has been used in the clinical treatment of rheumatic diseases for more than 20 years with remarkable efficacy. HQC has been experimentally shown to exert anti-arthritic effects via the Wnt signaling pathway.

AIM OF THE STUDY

This study used clinical data mining, network analysis, and in vitro and in vivo tests to investigate the anti-arthritic and possible anti-inflammatory mechanism of HQC. Specifically, emphasis was placed on the function of the hsa_circ_0091,685/EIF4A3/IL-17 axis in the anti-inflammatory process.

MATERIALS AND METHODS

A random walk model was used to evaluate the effects of HQC on clinical immune inflammatory marker function in patients with RA. Network analysis was used to predict the potential target genes and pathways of HQC. Hematoxylin & eosin, safranin O-fast green and toluidine blue staining, immunohistochemistry, and transmission electron microscopy were performed to evaluate the anti-arthritic effects of HQC in rat models. Cell Counting Kit-8 assay, quantitative real-time polymerase chain reaction, western blotting, enzyme-linked immunosorbent assay, and RNA pull-down were used to study the anti-proliferation and anti-inflammatory mechanisms of HQC.

RESULTS

Patients with RA who underwent HQC treatment showed a significant reduction in inflammatory response levels, according to retrospective clinical study. Network analysis revealed that HQC potentially targeted genes and pathways related to inflammation, especially IL-6, IL-17, TNF-α, IL-23, and IL-17 signaling pathway. Animal experiments showed that HQC inhibits inflammation through the IL-17 signaling pathway in rat models. Cellular experiments showed that HQC-containing serum inhibited the inflammatory response in patients with RA-FLS or RA by blocking hsa_circ_0091,685 and EIF4A3 expression.

CONCLUSION

In RA patients, HQC reduces the inflammatory response. The antiproliferative and anti-inflammatory qualities of HQC are responsible for its therapeutic impact. The suppression of the hsa_circ_0091,685/EIF4A3/IL-17 axis was linked to these favorable outcomes.

Unveiling Novel Drug Targets and Emerging Therapies for Rheumatoid Arthritis: A Comprehensive Review

Rheumatoid arthritis (RA) is a chronic debilitating autoimmune disease, that causes joint damage, deformities, and decreased functionality. In addition, RA can also impact organs like the skin, lungs, eyes, and blood vessels. This autoimmune condition arises when the immune system erroneously targets the joint synovial membrane, resulting in synovitis, pannus formation, and cartilage damage. RA treatment is often holistic, integrating medication, physical therapy, and lifestyle modifications. Its main objective is to achieve remission or low disease activity by utilizing a "treat-to-target" approach that optimizes drug usage and dose adjustments based on clinical response and disease activity markers. The primary RA treatment uses disease-modifying antirheumatic drugs (DMARDs) that help to interrupt the inflammatory process. When there is an inadequate response, a combination of biologicals and DMARDs is recommended. Biological therapies target inflammatory pathways and have shown promising results in managing RA symptoms. Close monitoring for adverse effects and disease progression is critical to ensure optimal treatment outcomes. A deeper understanding of the pathways and mechanisms will allow new treatment strategies that minimize adverse effects and maintain quality of life. This review discusses the potential targets that can be used for designing and implementing precision medicine in RA treatment, spotlighting the latest breakthroughs in biologics, JAK inhibitors, IL-6 receptor antagonists, TNF blockers, and disease-modifying noncoding RNAs.

Nuclear miRNAs: Gene Regulation Activities

MicroRNAs (miRNAs) are small non-coding RNAs which contribute to the regulation of many physiological and pathological processes. Conventionally, miRNAs perform their activity in the cytoplasm where they regulate gene expression by interacting in a sequence-specific manner with mature messenger RNAs. Recent studies point to the presence of mature miRNAs in the nucleus. This review summarizes current findings regarding the molecular activities of nuclear miRNAs. These molecules can regulate gene expression at the transcriptional level by directly binding DNA on the promoter or the enhancer of regulated genes. miRNAs recruit different protein complexes to these regions, resulting in activation or repression of transcription, through a number of molecular mechanisms. Hematopoiesis is presented as a paradigmatic biological process whereby nuclear miRNAs possess a relevant regulatory role. Nuclear miRNAs can influence gene expression by affecting nuclear mRNA processing and by regulating pri-miRNA maturation, thus impacting the biogenesis of miRNAs themselves. Overall, nuclear miRNAs are biologically active molecules that can be critical for the fine tuning of gene expression and deserve further studies in a number of physiological and pathological conditions.

Circular RNAs in EMT-driven metastasis regulation: modulation of cancer cell plasticity, tumorigenesis and therapy resistance

The non-coding RNAs comprise a large part of human genome lack of capacity in encoding functional proteins. Among various members of non-coding RNAs, the circular RNAs (circRNAs) have been of importance in the pathogenesis of human diseases, especially cancer. The circRNAs have a unique closed loop structure and due to their stability, they are potential diagnostic and prognostic factors in cancer. The increasing evidences have highlighted the role of circRNAs in the modulation of proliferation and metastasis of cancer cells. On the other hand, metastasis has been responsible for up to 90% of cancer-related deaths in patients, requiring more investigation regarding the underlying mechanisms modulating this mechanism. EMT enhances metastasis and invasion of tumor cells, and can trigger resistance to therapy. The cells demonstrate dynamic changes during EMT including transformation from epithelial phenotype into mesenchymal phenotype and increase in N-cadherin and vimentin levels. The process of EMT is reversible and its reprogramming can disrupt the progression of tumor cells. The aim of current review is to understanding the interaction of circRNAs and EMT in human cancers and such interaction is beyond the regulation of cancer metastasis and can affect the response of tumor cells to chemotherapy and radiotherapy. The onco-suppressor circRNAs inhibit EMT, while the tumor-promoting circRNAs mediate EMT for acceleration of carcinogenesis. Moreover, the EMT-inducing transcription factors can be controlled by circRNAs in different human tumors.

The biogenesis, identification, and functionality of circWWP2 in lipopolysaccharide stimulated macrophages

CircRNA, a non-coding RNA, is an ideal biomarker and a suitable potential therapeutic target for various disease due to its high stability, species conservation and cell/tissue specificity. Our previous study has found a circular RNA WWP2 (circWWP2) was significantly decreased in chicken macrophages during bacterial infection. However, the function of circWWP2 in chicken macrophages remains unclear. In this study, it was demonstrated that circWWP2 was a stable circular RNA created by back-splicing of exons 2 to 4 of WWP2 via PCR amplification, Sanger sequencing, RNase R exonuclease digestion, and RT-qPCR. Moreover, bioinformatics analysis showed circWWP2 could interact with 13 miRNAs and target 3,264 genes, which were significantly enriched in lysosomes, IgA-producing intestinal immune networks for IgA production, and Notch signaling pathway. Furthermore, CCK8 and RT-qPCR indicated that overexpression of circWWP2 could promote lipopolysaccharide (LPS)-induced cellular injury by decreasing cell viability and increasing the expression levels of pro-inflammatory cytokines and pro-apoptosis genes, and NO production. CircWWP2 may exert a potential target for the treatment of bacterial infection. Further experiments are necessary to validate the specific mechanism that circWWP2 regulates LPS induced cellular immune responses.

mm9_circ_014683 regulates microglia polarization through canonical NFκB signaling pathway in diabetic retinopathy

Diabetic retinopathy (DR) is still the major cause of visual loss in working-aged people, one of the critical pathological processes are retinal microglia-mediated inflammation. Our previous study demonstrated that enhanced M1 microglial polarization was involved in retinal inflammation in DR, but the detailed mechanism needs further investigation. Circular RNAs (circRNAs) are important kind of noncoding RNAs involved in the regulation of various cell biological processes. Herein, the circRNA expression profiles of BV2 mouse microglia treated with or without glucose were detected, and a total of 347 differentially expressed circRNAs were identified in glucose-treated BV2 cells. The key circRNA mm9_circ_014683 increased after glucose stimulation. Inhibiting or overexpressing mm9_circ_014683 showed no effect on the proliferation and apoptosis of microglia. Inhibiting mm9_circ_014683 impeded M1 polarization and promoted M2 polarization, and overexpressing mm9_circ_014683 showed the opposite effect. A total of 216 differentially expressed genes were identified in mm9_circ_014683-knockdown BV2 cells, which were enriched in several signaling pathways, including the NFκB signaling pathway. Moreover, mm9_circ_014683 positively regulated the canonical, NFκB signaling pathway. Besides, mm9_circ_014683 was highly expressed in the retinal microglia of diabetic mice, and intraocular injection of Lv-circRNA inhibited M1 but enhanced M2 retinal microglial polarization. In conclusion, mm9_circ_014683 regulates microglial polarization through the canonical NFκB signaling pathway in diabetic retinopathy. This study may provide insight into the pathogenesis and treatment of DR.

Targeting the "tumor microenvironment": RNA-binding proteins in the spotlight in colorectal cancer therapy

Colorectal cancer (CRC) is the third most common cancer and has the second highest mortality rate among cancers. The development of CRC involves both genetic and epigenetic abnormalities, and recent research has focused on exploring the ex-transcriptome, particularly post-transcriptional modifications. RNA-binding proteins (RBPs) are emerging epigenetic regulators that play crucial roles in post-transcriptional events. Dysregulation of RBPs can result in aberrant expression of downstream target genes, thereby affecting the progression of colorectal tumors and the prognosis of patients. Recent studies have shown that RBPs can influence CRC pathogenesis and progression by regulating various components of the tumor microenvironment (TME). Although previous research on RBPs has primarily focused on their direct regulation of colorectal tumor development, their involvement in the remodeling of the TME has not been systematically reported. This review aims to highlight the significant role of RBPs in the intricate interactions within the CRC tumor microenvironment, including tumor immune microenvironment, inflammatory microenvironment, extracellular matrix, tumor vasculature, and CRC cancer stem cells. We also highlight several compounds under investigation for RBP-TME-based treatment of CRC, including small molecule inhibitors such as antisense oligonucleotides (ASOs), siRNAs, agonists, gene manipulation, and tumor vaccines. The insights gained from this review may lead to the development of RBP-based targeted novel therapeutic strategies aimed at modulating the TME, potentially inhibiting the progression and metastasis of CRC.

CircPRMT5 promotes progression of osteosarcoma by recruiting CNBP to regulate the translation and stability of CDK6 mRNA

Research has demonstrated that circular RNAs (circRNAs) exert critical functions in the occurrence and progression of numerous malignant tumors. CircPRMT5 was recently reported to be involved in the pathogenesis of cancers. However, the potential role of circPRMT5 in osteosarcoma needs further investigation. In present study, our results suggested that circPRMT5 was highly upregulated in osteosarcoma cells and mainly localizes in the cytoplasm. CircPRMT5 promoted the proliferation, migration and invasion capacities of osteosarcoma cells, and suppressed cell apoptosis. Knockdown of circPRMT5 exerted the opposite effects. Mechanically, circPRMT5 promoted the binding of CNBP to CDK6 mRNA, which enhanced the stability of CDK6 mRNA and facilitated its translation, thereby promoting the progression of osteosarcoma. Knockdown of CDK6 reversed the promoting effect of circPRMT5 on osteosarcoma cells. These findings suggest that circPRMT5 promotes osteosarcoma cell malignant activity by recruiting CNBP to regulate the translation and stability of CDK6 mRNA. Thus, circPRMT5 may represent a promising therapeutic target for osteosarcoma.

Integration of network pharmacology and experimental verifications reveals the Bian-Se-Tong mixture can alleviate constipation in STC rats by reducing apoptosis of Cajal cells via activating PI3K-Akt signaling pathway

Bian-Se-Tong mixture (BSTM) is an optimized formulation based on the classical prescription "Zhizhu pill", which is widely used in the clinical treatment of slow-transit constipation (STC). The potential molecular mechanism of BSTM therapy for STC was investigated by network pharmacology prediction combined with animal experiments. The active components of BSTM were screened via the TCMSP platform. The GeneCards, OMIM and DrugBank databases were used to search for STC targets. With the help of the Biogenet tool, a protein interaction network between drugs and disease targets was constructed, and the intersection network of the two was extracted to obtain the key targets of BSTM in the treatment of STC. GO and KEGG enrichment analyses of key targets were carried out with Metascape. Loperamide hydrochloride was used to establish an STC rat model, and the key targets and related pathways were preliminarily verified. The important signaling pathways included the PI3K-Akt, MAPK, IL-17, cAMP, and cell cycle signaling pathways. The experimental results showed that BSTM treatment increased the body weight of STC rats and increased the fecal particle number, fecal water content and intestinal carbon ink promotion rate within 24 h. Further pathological changes in the colon of the rats were also observed. In-depth mechanistic studies have shown that BSTM can significantly reduce the apoptosis of intestinal Cajal cells, downregulate the expression of Bax and c-Caspase 3, upregulate the expression of Bcl-2 and c-kit, and promote the phosphorylation of AKT. The results showed that BSTM can significantly relieve constipation in STC rats via a mechanism related to activating the PI3K-Akt signaling pathway and improving Cajal cell apoptosis.

Sex-associated microRNAs potentially implicated in sporadic Alzheimer's disease (sAD)

BACKGROUND

The onset and pathology of sporadic Alzheimer's disease (sAD) seem to be affected by both sex and genetic mechanisms. Evidence supports that the high prevalence of sAD in women, worldwide, may be attributed to an interplay among aging, sex, and lifestyle, influenced by genetics, metabolic changes, and hormones. Interestingly, epigenetic mechanisms such as microRNAs (miRNAs), known as master regulators of gene expression, may contribute to this observed sexual dimorphism in sAD.

OBJECTIVES

To investigate the potential impact of sex-associated miRNAs on processes manifesting sAD pathology, as described by the Tau-driven Adverse Outcome Pathway (AOP) leading to memory loss.

METHODS

Using publicly available human miRNA datasets, sex-biased miRNAs, defined as differentially expressed by sex in tissues possibly affected by sAD pathology, were collected. In addition, sex hormone-related miRNAs were also retrieved from the literature. The compiled sex-biased and sex hormone-related miRNAs were further plugged into the dysregulated processes of the Tau-driven AOP for memory loss.

RESULTS

Several miRNAs, previously identified as sex-associated, were implicated in dysregulated processes associated with the manifestation of sAD pathology. Importantly, the described pathology processes were not confined to a particular sex. A mechanistic-based approach utilizing miRNAs was adopted in order to elucidate the link between sex and biological processes potentially involved in the development of memory loss.

CONCLUSIONS

The identification of sex-associated miRNAs involved in the early processes manifesting memory loss may shed light to the complex molecular mechanisms underlying sAD pathogenesis in a sex-specific manner.

More than the SRY: The Non-Coding Landscape of the Y Chromosome and Its Importance in Human Disease

Historically, the Y chromosome has presented challenges to classical methodology and philosophy of understanding the differences between males and females. A genetic unsolved puzzle, the Y chromosome was the last chromosome to be fully sequenced. With the advent of the Human Genome Project came a realization that the human genome is more than just genes encoding proteins, and an entire universe of RNA was discovered. This dark matter of biology and the black box surrounding the Y chromosome have collided over the last few years, as increasing numbers of non-coding RNAs have been identified across the length of the Y chromosome, many of which have played significant roles in disease. In this review, we will uncover what is known about the connections between the Y chromosome and the non-coding RNA universe that originates from it, particularly as it relates to long non-coding RNAs, microRNAs and circular RNAs.

Magnetic Graphene Oxide Nanocomposites Boosts Craniomaxillofacial Bone Regeneration by Modulating circAars/miR-128-3p/SMAD5 Signaling Axis

Background

The ability of nanomaterials to induce osteogenic differentiation is limited, which seriously imped the repair of craniomaxillofacial bone defect. Magnetic graphene oxide (MGO) nanocomposites with the excellent physicochemical properties have great potential in bone tissue engineering. In this study, we aim to explore the craniomaxillofacial bone defect repairment effect of MGO nanocomposites and its underlying mechanism.

Methods

The biocompatibility of MGO nanocomposites was verified by CCK8, live/dead staining and cytoskeleton staining. The function of MGO nanocomposites induced osteogenic differentiation of BMSCs was investigated by ALP activity detection, mineralized nodules staining, detection of osteogenic genes and proteins, and immune-histochemical staining. BMSCs with or without MGO osteogenic differentiation induction were collected and subjected to high-throughput circular ribonucleic acids (circRNAs) sequencing, and then crucial circRNA circAars was screened and identified. Bioinformatics analysis, Dual-luciferase reporter assay, RNA binding protein immunoprecipitation (RIP), fluorescence in situ hybridization (FISH) and osteogenic-related examinations were used to further explore the ability of circAars to participate in MGO nanocomposites regulation of osteogenic differentiation of BMSCs and its potential mechanism. Furthermore, critical-sized calvarial defects were constructed and were performed to verify the osteogenic differentiation induction effects and its potential mechanism induced by MGO nanocomposites.

Results

We verify the good biocompatibility and osteogenic differentiation improvement effects of BMSCs mediated by MGO nanocomposites. Furthermore, a new circRNA-circAars, we find and identify, is obviously upregulated in BMSCs mediated by MGO nanocomposites. Silencing circAars could significantly decrease the osteogenic ability of MGO nanocomposites. The underlying mechanism involved circAars sponging miR-128-3p to regulate the expression of SMAD5, which played an important role in the repair craniomaxillofacial bone defects mediated by MGO nanocomposites.

Conclusion

We found that MGO nanocomposites regulated osteogenic differentiation of BMSCs via the circAars/miR-128-3p/SMAD5 pathway, which provided a feasible and effective strategy for the treatment of craniomaxillofacial bone defects.

The regulatory role and clinical application prospects of circRNA in the occurrence and development of CNS tumors

BACKGROUND

Central nervous system (CNS) tumors originate from the spinal cord or brain. The study showed that even with aggressive treatment, malignant CNS tumors have high mortality rates. However, CNS tumor risk factors and molecular mechanisms have not been verified. Due to the reasons mentioned above, diagnosis and treatment of CNS tumors in clinical practice are currently fraught with difficulties. Circular RNAs (circRNAs), single-stranded ncRNAs with covalently closed continuous structures, are essential to CNS tumor development. Growing evidence has proved the numeral critical biological functions of circRNAs for disease progression: sponging to miRNAs, regulating gene transcription and splicing, interacting with proteins, encoding proteins/peptides, and expressing in exosomes.

AIMS

This review aims to summarize current progress regarding the molecular mechanism of circRNA in CNS tumors and to explore the possibilities of clinical application based on circRNA in CNS tumors.

METHODS

We have summarized studies of circRNA in CNS tumors in Pubmed.

RESULTS

This review summarized their connection with CNS tumors and their functions, biogenesis, and biological properties. Furthermore, we introduced current advances in clinical RNA-related technologies. Then we discussed the diagnostic and therapeutic potential (especially for immunotherapy, chemotherapy, and radiotherapy) of circRNA in CNS tumors in the context of the recent advanced research and application of RNA in clinics.

CONCLUSIONS

CircRNA are increasingly proven to participate in decveloping CNS tumors. An in-depth study of the causal mechanisms of circRNAs in CNS tomor progression will ultimately advance their implementation in the clinic and developing new strategies for preventing and treating CNS tumors.

Exploring the mechanism of action of Shuangyang houbitong granules in the treatment of acute pharyngitis based on network pharmacology and molecular docking

BACKGROUND

Acute pharyngitis (AP) refers to the acute inflammation of the pharynx, characterized by swelling and pain in the throat. Shuangyang houbitong granules (SHG), a traditional Chinese medicine compound, have been found to be effective in providing relief from symptoms associated with AP.

METHODS

The chemical components of SHG were screened using Traditional Chinese Medicine Systems Pharmacology database, HERB database, and China National Knowledge Infrastructure. The targets of the granules were predicted using SwissTargetPrediction database. A network was constructed based on the targets of AP obtained from Genecards database, and protein-protein interaction analysis was performed on the intersection targets using STRING database. Key targets were screened for Gene Ontology and Kyoto Encyclopedia of Genes and Genomes enrichment analysis, and the binding activity of components and targets was predicted using AutoDockTools-1.5.7.

RESULTS

A total of 65 components of SHG that met the screening criteria were retrieved, resulting in 867 corresponding targets. Additionally, 1086 AP target genes were retrieved, and 272 gene targets were obtained from the intersection as potential targets for SHG in the treatment of AP. Molecular docking results showed that the core components genkwanin, acacetin, apigenin, quercetin can stably bind to the core targets glyceraldehyde 3-phosphate dehydrogenase, interleukin 6, tumor necrosis factor, serine/threonine protein kinase, tumor protein 53, and epidermal growth factor receptor.

CONCLUSION

The research results preliminarily predict and verify the mechanism of action of SHG in the treatment of AP, providing insights for further in-depth research.

Rheumatoid arthritis: pathogenesis and therapeutic advances

Rheumatoid arthritis (RA) is a chronic autoimmune disease characterized by the unresolved synovial inflammation for tissues-destructive consequence, which remains one of significant causes of disability and labor loss, affecting about 0.2-1% global population. Although treatments with disease-modifying antirheumatic drugs (DMARDs) are effective to control inflammation and decrease bone destruction, the overall remission rates of RA still stay at a low level. Therefore, uncovering the pathogenesis of RA and expediting clinical transformation are imminently in need. Here, we summarize the immunological basis, inflammatory pathways, genetic and epigenetic alterations, and metabolic disorders in RA, with highlights on the abnormality of immune cells atlas, epigenetics, and immunometabolism. Besides an overview of first-line medications including conventional DMARDs, biologics, and small molecule agents, we discuss in depth promising targeted therapies under clinical or preclinical trials, especially epigenetic and metabolic regulators. Additionally, prospects on precision medicine based on synovial biopsy or RNA-sequencing and cell therapies of mesenchymal stem cells or chimeric antigen receptor T-cell are also looked forward. The advancements of pathogenesis and innovations of therapies in RA accelerates the progress of RA treatments.

The expression, function, and network regulation of circDNAJB6 in chicken macrophages under lipopolysaccharide (LPS) stimulation

Circular RNAs (circRNA) originate from back-splicing events that link a downstream 5'splice site to an upstream 3' splice site. Circular RNA has been shown to be involved in gene expression, interacting with microRNA and RNA binding proteins to affect transcription, splicing, translation, and other processes. However, little is known about the potential function of chicken circRNAs that trigger the pathogenesis. In a previous study, a circular RNA DNAJB6 (circDNAJB6) was identified as a typical covalently closed circular RNA that is abundant in chicken macrophages upon bacterial infection. It was identified that circDNAJB6 was formed by reverse splicing of exons 2 to 5 of the DNAJB6 gene by PCR amplification, Sanger sequencing, and RNase R exonuclease treatment. Moreover, circDNAJB6 had ability to exacerbate the lipopolysaccharides (LPS) induced cellular injury via reducing cell viability, increasing NO product and pro-inflammatory cytokines. In addition, bioinformatic analysis showed that five miRNAs were identified to interact with circDNAJB6, potentially targeting 75 genes, which were significantly enriched in the pathways of autophagy-animal and MAPK signaling. This study has provided and broadened a better understanding the function of circDNAJB6, which may exert potential biomarkers and act as potential targets for the treatment of bacterial infection.

Exosomal Osteoclast-Derived miRNA in Rheumatoid Arthritis: From Their Pathogenesis in Bone Erosion to New Therapeutic Approaches

Rheumatoid arthritis (RA) is an autoimmune disease that causes inflammation, pain, and ultimately, bone erosion of the joints. The causes of this disease are multifactorial, including genetic factors, such as the presence of the human leukocyte antigen (HLA)-DRB1*04 variant, alterations in the microbiota, or immune factors including increased cytotoxic T lymphocytes (CTLs), neutrophils, or elevated M1 macrophages which, taken together, produce high levels of pro-inflammatory cytokines. In this review, we focused on the function exerted by osteoclasts on osteoblasts and other osteoclasts by means of the release of exosomal microRNAs (miRNAs). Based on a thorough revision, we classified these molecules into three categories according to their function: osteoclast inhibitors (miR-23a, miR-29b, and miR-214), osteoblast inhibitors (miR-22-3p, miR-26a, miR-27a, miR-29a, miR-125b, and miR-146a), and osteoblast enhancers (miR-20a, miR-34a, miR-96, miR-106a, miR-142, miR-199a, miR-324, and miR-486b). Finally, we analyzed potential therapeutic targets of these exosomal miRNAs, such as the use of antagomiRs, blockmiRs, agomiRs and competitive endogenous RNAs (ceRNAs), which are already being tested in murine and ex vivo models of RA. These strategies might have an important role in reestablishing the regulation of osteoclast and osteoblast differentiation making progress in the development of personalized medicine.

Current situation and trend of non-coding RNA in rheumatoid arthritis: a review and bibliometric analysis

Background

Rheumatoid arthritis (RA) is a chronic, systemic autoimmune disease that affects multiple joints and has adverse effects on various organs throughout the body, often leading to a poor prognosis. Recent studies have shown significant progress in the research of non-coding RNAs (ncRNAs) in RA. Therefore, this study aims to comprehensively assess the current status and research trends of ncRNAs in RA through a bibliometric analysis.

Methods

This study retrieved articles relevant to ncRNAs and RA from the Science Citation Index Expanded Database of the Web of Science Core Collection between January 1st, 2003, and July 31st, 2023. The relevant articles were screened based on the inclusion criteria. VOSviewer and CiteSpace are utilized for bibliometric and visual analysis.

Results

A total of 1697 publications were included in this study, and there was a noticeable increase in annual publications from January 1st, 2003, to July 31st, 2023. China, the United States, and the United Kingdom were the most productive countries in this field, contributing to 43.81%, 13.09%, and 3.87% of the publications. Anhui Medical University and Lu Qianjin were identified as the most influential institution and author. Frontiers In Immunology stood out as the most prolific journal, while Arthritis & Rheumatology was the most co-cited journal. Additionally, the research related to "circular RNA", "oxidative stress", "proliferation", and "migration" have emerged as new hotspots in the field.

Conclusion

In this study, we have summarized the publication characteristics related to ncRNA and RA and identified the most productive countries, institutions, authors, journals, hot topics, and trends.

A circRNA ceRNA network involved in cognitive dysfunction after chronic cerebral hypoperfusion

Chronic Cerebral Hypoperfusion (CCH) is associated with cognitive dysfunction, the underlying mechanisms of which remain elusive, hindering the development of effective therapeutic approaches. In this study, we employed an established CCH animal model to delve into neuropathological alterations like oxidative stress, inflammation, neurotransmitter synthesis deficits, and other morphological alterations. Our findings revealed that while the number of neurons remained unchanged, there was a significant reduction in neuronal fibers post-CCH, as evidenced by microtubule-associated protein 2 (MAP2) staining. Moreover, myelin basic protein (MBP) staining showed exacerbated demyelination of neuronal fibers. Furthermore, we observed increased neuroinflammation, proliferation, and activation of astrocytes and microglia, as well as synaptic loss and microglial-mediated synapse engulfment post-CCH. Utilizing RNA sequencing, differential expression analysis displayed alterations in both mRNAs and circRNAs. Following gene ontology (GO) and Kyoto Encyclopedia of Genes and Genomes (KEGG) enrichment analyses, both showed significant enrichment in immunological and inflammation-related terms and pathways. Importantly, the differentially expressed circular RNAs (DE circRNAs) exhibited a notable coexpression pattern with DE mRNAs. The ternary circRNA-miRNA-mRNA competing endogenous RNAs (ceRNA) network was constructed, and subsequent analysis reiterated the significance of neuroimmunological and neuroinflammatory dysfunction in CCH-induced neuropathological changes and cognitive dysfunction. This study underscores the potential role of circRNAs in these processes, suggesting them as promising therapeutic targets to mitigate the detrimental effects of CCH.

Mechanism through which the hsa-circ_0000992- hsa- miR- 936-AKT3 regulatory network promotes the PM2.5-induced inflammatory response in human bronchial epithelial cells

BACKGROUND

Studies have shown that fine particulate matter (PM2.5) remains a significant problem in developing countries and plays a critical role in the onset and progression of respiratory illnesses. Circular RNAs (circRNAs) are involved in many pathophysiological processes,but their relationship to PM2.5 pollution is largely unexplored.

OBJECTIVES

To elucidate the functional role of hsa_circ_0000992 in PM2.5-induced inflammation in a human bronchial epithelial cell line (16HBE) and to clarify whether the competing endogenous RNA (ceRNA) mechanism is involved in the interrelationships between hsa_circ_0000992 and hsa-miR-936 and the inflammatory signaling pathways.

METHODS

Detection of inflammatory factors in 16HBE cells exposed to PM2.5 by RT-qPCR and ELISA.High throughput sequencing and bioinformatics analysis methods were used to screen circRNA.The bioinformatics analysis method western blotting and dual-luciferase reporter gene system were used to verify mechanisms associated with circRNA.

RESULTS

PM2.5 cause inflammation in the 16HBE cells. High throughput sequencing and RT-qPCR result revealed that the expression of hsa_circ_0000992 was markedly up-regulated in 16HBE exposed to PM2.5. The binding sites between hsa_circ_0000992 and hsa-miR-936 was confirmed by dual-luciferase reporter gene system.Western blotting and RT-qPCR showed that hsa_circ_0000992 can interact with hsa-miR-936 to regulate AKT serine/threonine kinase 3(AKT3),thereby activating the PI3K/AKT pathway and ultimately promoting the expression of interleukin (IL)- 1β and IL-8.

CONCLUSION

PM2.5 can induce the inflammatory response in 16HBE cells by activating the PI3K/AKT pathway. The expression of hsa_circ_0000992 increased when PM2.5 stimulated 16HBE cells,and the circRNA could then regulate the inflammatory response.Hsa_circ_0000992 regulates the hsa-miR-936/AKT3 axis through the ceRNA mechanism,thereby activating the PI3K/AKT signaling pathway,increasing the expression of cellular inflammatory factors,and promoting PM2.5-induced respiratory inflammation.

hsa_circ_0037722 Drives Keloid Formation by Interacting with miR-140-3p and NR2F2

Keloids can invade normal skin tissues to lead to itching, pain, hemorrhaging and suppuration, thereby affecting the mental health of patients. circRNAs can participate in keloids formation, but the role of hsa_circ_0037722 in keloids is still unknown. The goal of our study was to reveal the role of hsa_circ_0037722 in keloids. The levels of hsa_circ_0037722, miR-140-3p and NR2F2 in keloids was confirmed by qRT-PCR. Cell experiments were applied to assess the effect of hsa_circ_0037722/miR-140-3p/NR2F2 axis on keloids formation. In addition, the correlation among hsa_circ_0037722, miR-140-3p and NR2F2 was confirmed by luciferase assay. hsa_circ_0037722 and NR2F2 were upregulated in keloids tissues and keloids fibroblasts, whereas miR-140-3p was downregulated in keloids tissues and keloids fibroblasts. The abilities of proliferation and metastasis of keloids fibroblasts were impaired by silencing hsa_circ_0037722. However, miR-140-3p inhibitor or NR2F2 overexpression could restore the inhibitory function of hsa_circ_0037722 knockdown in keloid fibroblasts due to their targeting relationship. Taken together, hsa_circ_0037722 can facilitate keloids formation by interacting with miR-140-3p to relieve the suppression of miR-140-3p for NR2F2. The findings of this study may provide a novel idea for developing molecular targeted therapies for keloid.

Immune cell-specific and common molecular signatures in rheumatoid arthritis through molecular network approaches

Rheumatoid arthritis (RA) is an autoimmune disorder and common symptom of RA is chronic synovial inflammation. The pathogenesis of RA is not fully understood. Therefore, we aimed to identify underlying common and distinct molecular signatures and pathways among ten types of tissue and cells obtained from patients with RA. In this study, transcriptomic data including synovial tissues, macrophages, blood, T cells, CD4+T cells, CD8+T cells, natural killer T (NKT), cells natural killer (NK) cells, neutrophils, and monocyte cells were analyzed with an integrative and comparative network biology perspective. Each dataset yielded a list of differentially expressed genes as well as a reconstruction of the tissue-specific protein-protein interaction (PPI) network. Molecular signatures were identified by a statistical test using the hypergeometric probability density function by employing the interactions of transcriptional regulators and PPI. Reporter metabolites of each dataset were determined by using genome-scale metabolic networks. It was defined as the common hub proteins, novel molecular signatures, and metabolites in two or more tissue types while immune cell-specific molecular signatures were identified, too. Importantly, miR-155-5p is found as a common miRNA in all tissues. Moreover, NCOA3, PRKDC and miR-3160 might be novel molecular signatures for RA. Our results establish a novel approach for identifying immune cell-specific molecular signatures of RA and provide insights into the role of common tissue-specific genes, miRNAs, TFs, receptors, and reporter metabolites. Experimental research should be used to validate the corresponding genes, miRNAs, and metabolites.

Long noncoding RNA/circular RNA regulates competitive endogenous RNA networks in rheumatoid arthritis: molecular mechanisms and traditional Chinese medicine therapeutic significances

Rheumatoid arthritis (RA) is a systemic and autoimmune disease that is mainly featured abnormal fibroblast-like synoviocyte (FLS) proliferation and inflammatory cell infiltration. Abnormal expression or function of long noncoding RNAs (lncRNAs) and circular RNAs (circRNAs) are closely related to human diseases, including RA. There has been increasing evidence showing that in the competitive endogenous RNA (ceRNA) networks, both lncRNA and circRNA are vital in the biological functions of cells. Nevertheless, the exact mechanism of ceRNA in RA remains to be investigated. Herein, we summarized the molecular potencies of lncRNA/circRNA-mediated ceRNA networks in RA, with emphasis on the phenotypic regulation of ceRNA in the progression of RA, including regulation of proliferation, invasion, inflammation and apoptosis, as well as the role of ceRNA in traditional Chinese medicine (TCM) in the treatment of RA. In addition, we also discussed the future direction and potential clinical value of ceRNA in the treatment of RA, which may provide potential reference value for clinical trials of TCM therapy for the treatment of RA.Key messagesLong noncoding RNA/circular RNA can work as the competitive endogenous RNA sponge and participate in the pathogenesis of rheumatoid arthritis.Traditional Chinese medicine and its agents have shown potential roles in the prevention and treatment of rheumatoid arthritis via competitive endogenous RNA.

Circular RNA in Multiple Sclerosis: Pathogenicity and Potential Biomarker Development: A Systematic Review

Multiple sclerosis (MS) is a complex autoimmune disorder of the CNS that affects millions of people worldwide. The causes of the disease remain unknown despite extensive efforts to understand it. CircRNAs are a unique class of endogenous non-coding RNA that are abundant, stable, conserved, and specifically expressed molecules, making them a promising biomarker of diseases. This review investigates the role of circRNA in MS pathogenicity and their potential as a biomarker through a comprehensive literature search conducted in 8 scientific databases. The studies found that there are differentially expressed circRNAs in MS patients compared to healthy controls (HC), and this difference is even more pronounced in different MS subtypes. Enrichment of circRNAs in linkage disequilibrium (LD) blocks that harbor MS-associated SNPs suggests that these SNPs manipulate the levels of circRNAs in the surrounding area, contributing to disease pathogenicity. While circRNA shows promise as an indicator or biomarker for MS disease pathology, further research is needed to fully explore its potential and impact on human biology.

Mechanistic insights into the alterations and regulation of the AKT signaling pathway in diabetic retinopathy

In the early stages of diabetic retinopathy (DR), diabetes-related hyperglycemia directly inhibits the AKT signaling pathway by increasing oxidative stress or inhibiting growth factor expression, which leads to retinal cell apoptosis, nerve proliferation and fundus microvascular disease. However, due to compensatory vascular hyperplasia in the late stage of DR, the vascular endothelial growth factor (VEGF)/phosphatidylinositol 3 kinase (PI3K)/AKT cascade is activated, resulting in opposite levels of AKT regulation compared with the early stage. Studies have shown that many factors, including insulin, insulin-like growth factor-1 (IGF-1), VEGF and others, can regulate the AKT pathway. Disruption of the insulin pathway decreases AKT activation. IGF-1 downregulation decreases the activation of AKT in DR, which abrogates the neuroprotective effect, upregulates VEGF expression and thus induces neovascularization. Although inhibiting VEGF is the main treatment for neovascularization in DR, excessive inhibition may lead to apoptosis in inner retinal neurons. AKT pathway substrates, including mammalian target of rapamycin (mTOR), forkhead box O (FOXO), glycogen synthase kinase-3 (GSK-3)/nuclear factor erythroid 2-related factor 2 (Nrf2), and nuclear factor kappa-B (NF-κB), are a research focus. mTOR inhibitors can delay or prevent retinal microangiopathy, whereas low mTOR activity can decrease retinal protein synthesis. Inactivated AKT fails to inhibit FOXO and thus causes apoptosis. The GSK-3/Nrf2 cascade regulates oxidation and inflammation in DR. NF-κB is activated in diabetic retinas and is involved in inflammation and apoptosis. Many pathways or vital activities, such as the Janus kinase (JAK)/signal transducer and activator of transcription (STAT) and mitogen-activated protein kinase (MAPK) signaling pathways, interact with the AKT pathway to influence DR development. Numerous regulatory methods can simultaneously impact the AKT pathway and other pathways, and it is essential to consider both the connections and interactions between these pathways. In this review, we summarize changes in the AKT signaling pathway in DR and targeted drugs based on these potential sites.

Exploring CircRNA N6-methyladenosine in human rheumatoid arthritis: Hyper-methylated hsa_circ_0007259 as a potential biomarker and its involvement in the hsa_circ_0007259/hsa_miR-21-5p/STAT3 axis

BACKGROUND

N6-methyladenosine (m6A) is a highly enriched modification found in circular RNAs (CircRNAs); however, the ability and mechanism of CircRNAs to encode for m6A function in rheumatoid arthritis (RA) remain poorly understood.

METHODS

We utilized an epitranscriptomic microarray to measure levels and quantities of m6A methylated CircRNAs in synovial tissues of patients with RA and osteoarthritis (OA). We then utilized methylated RNA immunoprecipitation- and MazF-quantitative PCR to identify and validate differentially m6A-methylated RNAs between the groups, conducted a functional enrichment analysis, and selected protein-protein interaction hub genes. Lastly, we predicted and validated the CircRNA/miRNA/mRNA interaction networks.

RESULTS

We detected 4,845 CircRNAs containing m6A in our samples, with 53 CircRNAs upregulated, and 139 CircRNAs downregulated compared to human OA synovial tissue (|fold change| ≥ 1.2 and p ≤ 0.05). The differentially m6A-modified CircRNAs were associated with the interleukin-6-mediated signaling pathway, with an increase in relative m6A-methylated levels of hsa_circ_0007259 in human RA, a significant decrease in hsa_miR-21-5p, and an increase in signal transducer and activator of transcription 3（STAT3）. The Luciferase Reporter Gene assay verified the binding of hsa_circ_0007259 to hsa_miR-21-5p and the subsequent binding of hsa_miR-21-5p to STAT3.

CONCLUSION

We showed a notable increase in the relative m6A-methylated levels of hsa_circ_0007259 in human RA, indicating a potential role of hypermethylated hsa_circ_0007259 in RA pathogenesis. This may provide valuable insight into the mechanism of RA and the possibility of utilizing hsa_circ_0007259 as a valuable biomarker.

Identification of biomarkers associated with immune scores in diabetic retinopathy

Background

Diabetic retinopathy (DR) causes irreversible visual impairment in diabetes mellitus (DM) patients. Immunity played a crucial role in DR. Nevertheless, the triggering mechanism of DR was not yet thorough enough. Herein, we aim to identify the immune-associated genes as biomarkers associated with immune scores that can distinguish early DR from DM without DR.

Methods

In this study, total RNA of peripheral blood mononuclear cell (PBMC) samples from 15 non-proliferative DR patients and 15 DM patients without DR were collected and the transcriptome sequencing data were extracted. Firstly, the target genes were obtained by intersecting the differentially expressed genes (DEGs), which were screened by "limma", and the module genes (related to immune scores), which were screened by "WGCNA". In order to screen for the crucial genes, three machine learning algorithms were implemented, and a receiver operating characteristic (ROC) curve was used to obtain the diagnostic genes. Moreover, the gene set enrichment analysis (GSEA) was performed to understand the function of diagnostic genes, and analysis of the proportions of immune cells and their association with diagnostic genes was performed to analyze the pathogenesis of DR. Furthermore, the regulatory network of TF-mRNA-miRNA was built to reveal the possible regulation of diagnostic genes. Finally, the quantitative real-time polymerase chain reaction (qRT-PCR) was performed to verify the mRNA level of diagnostic genes.

Results

A total of three immune-associated diagnostic genes, namely, FAM209B, POM121L1P, and PTGES, were obtained, and their expression was increased in PBMC samples of DR, and qRT-PCR results confirmed these results. Moreover, the functions of these genes were associated with immune response. The expression of POM121L1P and PTGES was significantly negatively associated with naive B cells, and the expression of FAM209B was significantly negatively associated with immature dendritic cells. Moreover, ESR1 could regulate both FAM209B and PTGES.

Conclusion

This study identified three immune-associated diagnostic genes, FAM209B, POM121L1P, and PTGES, as biomarkers associated with immune scores in DR for the first time. This finding might proffer a novel perspective of the triggering mechanism of DR, and help to understand the role of immune-associated genes in the molecular mechanism of DR more deeply.

Dysregulation of circRNAs in rheumatoid arthritis, with special emphasis on circRNAs secreted by exosomes and the crosstalk between circRNAs and RNA methylations

BACKGROUND

Rheumatoid arthritis (RA) is an autoimmune disease caused by a variety of unknown factors. It mainly occurs in the small joints of hands and feet, leading to cartilage destruction and bone erosion. Various pathologic mechanisms such as exosomes and RNA methylations are involved in the pathogenesis of RA.

METHODS

This work searches PubMed, Web of Science (SCIE) and Science Direct Online (SDOL) databases, it role of abnormally expressed circulating RNAs (circRNAs) in the pathogenesis of RA was summarized. And the relationship between circRNAs and exosomes and methylations.

RESULTS

Both the abnormal expression of circRNAs and the sponge effect of circRNAs on microRNAs (miRNAs) affect the pathogenesis of RA by regulating target genes. CircRNAs affect the proliferation, migration and inflammatory reaction of RA-fibroblast-like synovial cells (FLSs), circRNAs in peripheral blood mononuclear cells (PBMCs) and macrophages also participate in the pathological mechanism of RA (Fig. 1). CircRNAs in exosomes are closely related to the pathogenesis of RA. In addition, exosomal circRNAs and the relationship between circRNAs and RNA methylations are closely related to the pathogenesis of RA.

CONCLUSION

CircRNAs play an important role in the pathogenesis of RA and have the potential to be a new target for the diagnosis and treatment of RA. However, the development of mature circRNAs for clinical application is not a small challenge.

circIFNGR2 regulating ankylosing spondylitis-associated inflammation through macrophage polarization

Macrophages activation is crucial in pathogenesis of rheumatic diseases like ankylosing spondylitis (AS). Circular RNAs (circRNAs)-induced macrophage-associated inflammation participates in many autoimmune diseases but remains elusive in AS. Here, we verified increased expression of circIFNGR2 in peripheral blood mononuclear cells from patients with AS and its expression levels were correlated with the AS severity. In vitro assays revealed that circIFNGR2 enhances macrophage proliferation, and regulates M1/M2 macrophage polarization and NF-κB/Akt pathways. We identified that circIFNGR2 promoted the expression of iNOS/TNFα and M1 polarization, and restrained M2 polarization by sponging miR-939. Additionally, the RNA-binding protein, eIF4A3, was found to enhance the production of circIFNGR2. Interestingly, miR-939 attenuated joint damage in collagen-induced arthritis mice, whereas circIFNGR2 reversed this effect. Our findings highlight the pro-inflammatory roles of eIF4A3-induced circIFNGR2 in AS by modulating macrophage-associated inflammation through miR-939.

circRNA landscape in dorsal root ganglia from mice with collagen antibody-induced arthritis

Circular RNAs are a novel class of RNA molecules that are covalently closed into a ring structure. They are an epigenetic regulatory mechanism, and their best-studied function is regulation of microRNA activity. As such circular RNAs may be involved in the switch from acute to chronic pain. They have previously been studied in the context of neuropathic pain models, but their importance in inflammation-induced chronic pain models is unexplored. Microarray analysis of dorsal root ganglia collected in the late phase of collagen antibody-induced arthritis (day 59) were used to elucidate the relevance of circular RNAs in the mechanical hypersensitivity caused by this model. 120 circular RNA genes were found to be significantly differentially regulated in female BALB/c mice with collagen antibody-induced arthritis. Six genes were chosen for RT-qPCR analysis in the late (day 54-60) as well as the inflammatory (day 11-12) phase of this model. This validated an increase in circNufip1 expression in the late phase of collagen antibody-induced arthritis. Additionally, it was found that circVps13 and circMicall1 are upregulated in the inflammatory phase. Interestingly, no changes were found in dorsal root ganglia from mice injected with Freund's Complete Adjuvant (day 3) nor mice with spared nerve injury (day 20), despite their similarities to inflammatory and late phase collagen antibody-induced arthritis, respectively. This study provides evidence that mild circular RNA changes occur in dorsal root ganglia of mice with collagen antibody-induced arthritis that are, bioinformatically, predicated to be involved in processes relevant to sensitization.

A review on circular RNAs and bacterial infections

Bacterial infections and related diseases have been a major burden on social public health and economic stability around the world. However, the effective diagnostic methods and therapeutic approaches to treat bacterial infections are still limited. As a group of non-coding RNA, circular RNAs (circRNAs) that were expressed specifically in host cells and played a key regulatory role have the potential to be of diagnostic and therapeutic value. In this review, we systematically summarize the role of circRNAs in common bacterial infections and their potential roles as diagnostic markers and therapeutic targets.

Role of ceRNA network in inflammatory cells of rheumatoid arthritis

Rheumatoid arthritis (RA) is a chronic inflammatory autoimmune disease caused by inflammatory cells. Various inflammatory cells involved in RA include fibroblast-like synoviocytes, macrophages, CD4+T-lymphocytes, B lymphocytes, osteoclasts and chondrocytes. The close interaction between various inflammatory cells leads to imbalance of immune response and disorder of the expression of mRNA in inflammatory cells. It helps to drive production of pro-inflammatory cytokines and stimulate specific antigen-specific T- and B-lymphocytes to produce autoantibodies which is an important pathogenic factor for RA. Competing endogenous RNA (ceRNA) can regulate the expression of mRNA by competitively binding to miRNA. The related ceRNA network is a new regulatory mechanism for RNA interaction. It has been found to be involved in the regulation of abnormal biological processes such as proliferation, apoptosis, invasion and release of inflammatory factors of RA inflammatory cells. Understanding the ceRNA network in 6 kinds of RA common inflammatory cells provides a new idea for further elucidating the pathogenesis of RA, and provides a theoretical basis for the discovery of new biomarkers and effective therapeutic targets.

Establishment and validation of the autophagy-related ceRNA network in irreversible pulpitis

BACKGROUND

The molecular mechanisms underlying the onset and progression of irreversible pulpitis have been studied for decades. Many studies have indicated a potential correlation between autophagy and this disease. Against the background of the competing endogenous RNA (ceRNA) theory, protein-coding RNA functions are linked with long noncoding RNAs (lncRNAs) and microRNAs (miRNAs). This mechanism has been widely studied in various fields but has rarely been reported in the context of irreversible pulpitis. The hub genes selected under this theory may represent the key to the interaction between autophagy and irreversible pulpitis.

RESULTS

Filtering and differential expression analyses of the GSE92681 dataset, which contains data from 7 inflamed and 5 healthy pulp tissue samples, were conducted. The results were intersected with autophagy-related genes (ARGs), and 36 differentially expressed ARGs (DE-ARGs) were identified. Functional enrichment analysis and construction of the protein‒protein interaction (PPI) network of DE-ARGs were performed. Coexpression analysis was conducted between differentially expressed lncRNAs (DElncRNAs) and DE-ARGs, and 151 downregulated and 59 upregulated autophagy-related DElncRNAs (AR-DElncRNAs) were identified. StarBase and multiMiR were then used to predict related microRNAs of AR-DElncRNAs and DE-ARGs, respectively. We established ceRNA networks including 9 hub lncRNAs (HCP5 and AC112496.1 ↑; FENDRR, AC099850.1, ZSWIM8-AS1, DLX6-AS1, LAMTOR5-AS1, TMEM161B-AS1 and AC145207.5 ↓), which were validated by a qRT‒PCR analysis of pulp tissue from patients with irreversible pulpitis.

CONCLUSION

We constructed two networks consisting of 9 hub lncRNAs based on the comprehensive identification of autophagy-related ceRNAs. This study may provide novel insights into the interactive relationship between autophagy and irreversible pulpitis and identifies several lncRNAs that may serve as potential biological markers.

Exploring the chondroprotective effect of Chaenomeles speciosa on Glucose-6-Phosphate Isomerase model mice using an integrated approach of network pharmacology and experimental validation

ETHNOPHARMACOLOGICAL RELEVANCE

Traditional Chinese medicine (TCM) has been used in China for a long time and is gradually gaining more and more recognition worldwide. Chaenomeles speciosa (CSP) (Chinese Pinyin: mugua) is a medicinal and food herb that has long been used as a folk medicine for rheumatic diseases, yet its bioactive components and therapeutic mechanisms are not clear.

AIM OF THE STUDY

Exploring anti-inflammatory and chondroprotective effects of CSP on rheumatoid arthritis (RA) and its possible targets of action.

MATERIALS AND METHODS

In this study, we performed an integrated approach of network pharmacology, molecular docking and experimental studies to explore the potential mechanism of action of CSP in the treatment of cartilage damage in RA.

RESULTS

Studies have shown that Quercetin, ent-Epicatechin and Mairin may be the main active compounds of CSP in the treatment of RA, while AKT1, VEGFA, IL-1β, IL-6, MMP9 etc. are considered as core target proteins to which the main active compounds in CSP bind, as further confirmed by molecular docking. In addition, the potential molecular mechanism of CSP for the treatment of cartilage damage in RA predicted by network pharmacology analysis was validated by in vivo experiments. CSP was found to downregulate the expression of AKT1, VEGFA, IL-1β, IL-6, MMP9, ICAM1, VCAM1, MMP3, MMP13 and TNF-α and increase the expression of COL-2 in the joint tissue of Glucose-6-Phosphate Isomerase (G6PI) model mice. Thus CSP contributes to the treatment of rheumatoid arthritis cartilage destruction.

CONCLUSION

This study showed that CSP has multi-component, multi-target and multi-pathway characteristics in treating cartilage damage in RA, which can achieve the effect of treating RA by inhibiting the expression of inflammatory factors, reducing neovascularization and alleviating the damage to cartilage caused by the diffusion of synovial vascular opacities, and reducing the degradation of cartilage by MMPs to play a protective role in RA cartilage damage. In conclusion, this study indicates that CSP is a candidate Chinese medicine for further research in treating cartilage damage in RA.

The functions and networks of non-coding RNAs in the pathogenesis of Rheumatoid Arthritis

Rheumatoid Arthritis (RA) is a chronic autoimmune disease. Its main feature is inflammation of synovial tissue with irreversible joint damage and severe physical damage. Non-coding RNAs (ncRNAs) are a class of RNAs that do not have the ability to encode proteins but are vital regulators that mediate many fundamental cellular processes and play an essential role in the pathogenesis of RA. Multiple verified ncRNAs have been confirmed as a prospective biomarkers for diagnosing and treating RA. In this paper, we aim to sort out the role of ncRNAs in the pathogenesis of RA and provide new ideas for the diagnosis and treatment of RA.

Upregulation of HTRA1 mediated by the lncRNA NEAT1/miR-141-3p axis contributes to endometriosis development through activating NLRP3 inflammasome-mediated pyroptotic cell death and cellular inflammation

The present study identified a novel upstream long chain non-coding (lncRNA) NEAT1/miR-141-3p/HTRA1 axis that regulated the activation of NLR family pyrin domain containing 3 (NLRP3) inflammasome to modulate endometriosis (EM) development. Specifically, clinical data suggested that the expression of NLRP3 and apoptosis-associated speck-like protein containing CARD (ASC), the cleavage of caspase-1 and gasdermin D (GSDMD), and the production of inflammatory cytokines (interleukin (IL)-1β, IL-6, tumor necrosis factor (TNF)-α, and IL-18) were all significantly increased in the ectopic endometrium (EE) tissues, compared to the normal endometrium (NE) tissues. Then, through analyzing the datasets from GEO database (GSE2339, GSE58178, and GSE7305) using the GEO2R bioinformatics tools, we verified that HtrA Serine Peptidase 1 (HTRA1) was especially enriched in the EE tissues compared to the NE tissues. To further confirm the biological functions of HTRA1, HTRA1 was overexpressed or downregulated in primary human endometrial stromal cells (hESCs) isolated from NE tissues or EE tissues, respectively. The results showed that upregulation of HTRA1 activated NLRP3 inflammasome-mediated pyroptotic cell death and cellular inflammation in NE-derived hESCs, whereas silencing of HTRA1 played an opposite role in EE-derived hESCs. In addition, the lncRNA NEAT1/miR-141-3p axis was screened as the upstream regulator of HTRA1. Mechanistically, lncRNA NEAT1 sponged miR-141-3p to positively regulate HTRA1 in a competing endogenous RNA (ceRNA) mechanisms-dependent manner. The recovery experiments in hESCs from NE and EE tissues confirmed that lncRNA NEAT1 overexpression promoted NLRP3 inflammasome-mediated pyroptotic cell death through regulating the miR-141-3p/HTRA1 axis. Taken together, this study firstly uncovered the underlying mechanisms by which a novel lncRNA NEAT1/miR-141-3p/HTRA1-NLRP3 pathway contributed to the development of EM, which provided novel diagnostic and therapeutic biomarkers for this disease.

Mmu_circ_0000037 inhibits the progression of acute pancreatitis by miR-92a-3p/Pias1 axis

BACKGROUND

Acute pancreatitis (AP) is an inflammatory disease with high mortality. Previous study has suggested that circular RNAs are dysregulated and involved in the regulation of inflammatory responses in AP. This study aimed to investigate the function and regulatory mechanism underlying mmu_circ_0000037 in caerulein-induced AP cellular model.

METHODS

Caerulein-treated MPC-83 cells were used as an in vitro cellular model for AP. The expression levels of mmu_circ_0000037, microRNA (miR)-92a-3p, and protein inhibitor of activated STAT1 (Pias1) were detected by quantitative real-time polymerase chain reaction. Cell viability, amylase activity, apoptosis, and inflammatory response were detected by 3-(4,5-Dimethylthiazol-2-yl)-2,5-diphenyltetrazolium bromide, Amylase Assay Kit, flow cytometry, and enzyme-linked immunosorbent assays. The protein level was quantified by western blot analysis. The target interaction between miR-92a-3p and mmu_circ_0000037 or Pias1 were predicted by StarbaseV3.0 and validated by dual-luciferase reporter assay and RNA immunoprecipitation assay.

RESULTS

Mmu_circ_0000037 and Pias1 levels were decreased, whereas miR-92a-3p expression was elevated in caerulein-induced MPC-83 cells. Overexpression of mmu_circ_0000037 protected MPC-83 cells from caerulein-induced the decrease of cell viability, as well as the promotion of amylase activity, apoptosis and inflammation. MiR-92a-3p was targeted by mmu_circ_0000037, and miR-92a-3p overexpression rescued the effect of mmu_circ_0000037 on caerulein-induced MPC-83 cell injury. Pias1 was confirmed as a target of miR-92a-3p and mmu_circ_0000037 regulated the expression of Pias1 by sponging miR-92a-3p.

CONCLUSION

Mmu_circ_0000037 relieves caerulein-induced inflammatory injury in MPC-83 cells by targeting miR-92a-3p/Pias1 axis, providing a theoretical basis for the treatment of AP.

circRNA_17725 Promotes Macrophage Polarization towards M2 by Targeting FAM46C to Alleviate Arthritis

Accumulating studies have implicated that circular RNAs (circRNAs) play vital roles in the pathogenesis of rheumatoid arthritis (RA). Dysregulation of macrophage polarization leads to immune homeostatic imbalance in RA. However, the altering effects and mechanisms of circRNAs on macrophages polarization and immune homeostatic balance remain largely unclear. We aimed to investigate the potential role of circRNA_17725 in RA. The high-throughput sequence was performed to identify the dysregulated circRNAs in RA. We confirmed the data by CCK-8, EdU, and Annexin V/PI staining to elucidate the proliferation and apoptosis. The expressions of M1/M2-associated markers were confirmed using real-time PCR and flow cytometry analysis. Luciferase reporter assay and RNA Binding Protein Immunoprecipitation (RIP) were used to demonstrate the underlying mechanism of circRNA_17725. The altering effect of circRNA_17725 on macrophages in vivo was evaluated using collagen-induced arthritis (CIA) mouse model. circRNA_17725 was demonstrated to be downregulated in peripheral blood mononuclear cells and CD14+ monocytes from RA cases in contrast to healthy controls. The negative association between circRNA_17725 and the disease activity indexes (CRP, ESR, and DAS28) was observed, suggesting a vital role of circRNA_17725 in RA disease activity. Besides, after a coexpression analysis based on high-input sequencing and the bioinformatics analysis in MiRanda and TargetScan databases, a circRNA_17725-miR-4668-5p-FAM46C competing endogenous RNA (ceRNA) network was hypothesized. A series of cytology experiments in vitro have implicated that circRNA_17725 could inhibit the proliferation but enhance the apoptosis of macrophages. Decreased expression of TNF-α, IL-1β, and MMP-9 were observed in the supernatant of circRNA_17725-overexpressed Raw264.7 macrophages, implicating the inhibitory effect of circRNA_17725 on macrophage inflammatory mediators. Furthermore, circRNA_17725 could promote macrophage polarization towards M2 by targeting miR-4668-5p/FAM46C as a miRNA sponge. Additionally, circRNA_17725-overexpressed macrophages alleviated arthritis and protected against joint injuries and bone destruction by inducing macrophage polarization towards M2 in collagen-induced arthritis (CIA) mice. This study has suggested that circRNA_17725 regulated macrophage proliferation, apoptosis, inflammation, and polarization by sponging miR-4668-5p and upregulating FAM46C in RA.

hsa_circ_0000047 targeting miR-6720-5p/CYB5R2 axis alleviates inflammation and angiogenesis in diabetic retinopathy

Context: Diabetic retinopathy (DR) is a common complication of diabetes mellitus (DM). Circular RNAs (circRNAs) act as key regulators of DR development by regulating inflammation and angiogenesis.Objective: This study aimed to elucidate the function and mechanism of hsa_circ_0000047 in DR.Materials and methods: High glucose (HG) was used to induce human retinal microvascular endothelial cells (hRMECs) to construct a DR model in vitro. Qualitative real-time polymerase chain reaction (qRT-PCR) or western blotting were used to detected the levels of hsa_circ_0000047, miR-6720-5p, and CYB5R2 in DR and HG-indeced hRMECs. Cell functional experiments were performed to detect the change of viability, inflammation, migration, invasion, and angiogenesis of HG-induced hRMECs. Besides, the correlation between miR-6720-5p and hsa_circ_0000047/CYB5R2 was confirmed by luciferase assay and Pearson correlation analysis.Results: hsa_circ_0000047 and CYB5R2 were downregulated in DR, whereas miR-6720-5p was upregulated in DR. Cell functional experiments showed that hsa_circ_0000047 overexpression restrained viability, inflammation, migration, invasion, and angiogenesis of HG-induced hRMECs. Regarding mechanism, hsa_circ_0000047 could sponge miR-6720-5p to regulate CYB5R2 expression in hRMECs. Additionally, CYB5R2 knockdown reversed the effects of hsa_circ_0000047 overexpression on HG-induced hRMECs.Conclusion: Our study revealed that hsa_circ_0000047 alleviated inflammation and angiogenesis in HG-induced hRMECs by targeting the miR-6720-5p/CYB5R2 axis, which may be a novel biomarker for DR therapy.

Circular RNA CircCDKN2B−AS_006 Promotes the Tumor-like Growth and Metastasis of Rheumatoid Arthritis Synovial Fibroblasts by Targeting the miR−1258/RUNX1 Axis

Rheumatoid arthritis (RA) is an autoimmune polyarthritis in which synovial fibroblasts (SFs) play a major role in cartilage and bone destruction through tumor−like proliferation, migration, and invasion. Circular RNAs (circRNAs) have emerged as vital regulators for tumor progression. However, the regulatory role, clinical significance, and underlying mechanisms of circRNAs in RASF tumor−like growth and metastasis remain largely unknown. Differentially expressed circRNAs in synovium samples from patients with RA and patients with joint trauma were identified via RNA sequencing. Subsequently, in vitro and in vivo experiments were performed to investigate the functional roles of circCDKN2B−AS_006 in RASF proliferation, migration, and invasion. CircCDKN2B−AS_006 was upregulated in synovium samples from patients with RA and promoted the tumor-like proliferation, migration, and invasion of RASFs. Mechanistically, circCDKN2B−AS_006 was shown to regulate the expression of runt−related transcription factor 1 (RUNX1) by sponging miR-1258, influencing the Wnt/β−catenin signaling pathway, and promoting the epithelial−to−mesenchymal transition (EMT) in RASFs. Moreover, in the collagen−induced arthritis (CIA) mouse model, intra−articular injection of lentivirus−shcircCDKN2B−AS_006 was capable of alleviating the severity of arthritis and inhibiting the aggressive behaviors of SFs. Furthermore, the correlation analysis results revealed that the circCDKN2B−AS_006/miR−1258/RUNX1 axis in the synovium was correlated with the clinical indicators of RA patients. CircCDKN2B−AS_006 promoted the proliferation, migration, and invasion of RASFs by modulating the miR−1258/RUNX1 axis.

Circular RNA in autoimmune diseases: special emphasis on regulation mechanism in RA and SLE

BACKGROUND

Autoimmune diseases are diseases caused by tissue damage caused by the body's immune response to autoantibodies. Circular RNAs (CircRNAs) are a kind of special endogenous non-coding RNA that play a biological role by regulating gene transcription.

METHODS

In this work, we searched the PubMed, Web of Science (SCIE), National Science and Technology Library (NSTL), and ScienceDirect Online (SDOL) databases to summarize the impact of circRNAs on autoimmune diseases, especially the results of circRNAs in rheumatoid arthritis (RA) and systemic lupus erythematosus (SLE).

RESULTS

The study on the function of circRNAs and autoimmune diseases further deepened our understanding of the development and pathogenesis of autoimmune diseases. CircRNAs may act as miRNA sponges to regulate biological processes and affect the occurrence and development of autoimmune diseases. CircRNAs are closely related to the pathogenesis of RA and SLE and may become potential biomarkers for the diagnosis and treatment of RA and SLE.

CONCLUSION

CircRNAs play an important role in the pathogenesis of RA, SLE and other autoimmune diseases, and are expected to provide new biomarkers for the diagnosis and treatment of autoimmune diseases. However, the function and mechanism of circRNAs in autoimmune diseases need more comprehensive research.

A novel circular RNA circNLRP3 alleviated ricin toxin-induced TNF-α production through sponging miR-221-5p

Acting as microRNA (miRNA) sponges, circular RNAs (circRNAs) have been discovered to be critical modulators of inflammatory processes. Ricin Toxin (RT) is highly toxic to mammalian cells and low doses of RT can induce acute inflammation. However, current researches on the underlying mechanism and function of circRNA/miRNA network in RT-induced inflammation are limited. Previously, we found miR-221-5p was aberrant and associated with the inflammation of RT induction. In this study, based on the circRNA high-throughput sequencing (circRNA-seq), we obtained a novel circRNA termed circNLRP3 and revealed that circNLRP3 can sponge miR-221-5p, release its target mRNA A20, and further suppress NF-κB signaling pathway to alleviated RT-induced TNF-α production. Our findings elucidated a possible mechanistic link between the circNLRP3/miR-221-5p/A20 axis and RT-induced inflammatory response, which may broaden our understanding of RT poisoning.

Implications and theragnostic potentials of circular RNAs in rheumatic diseases

Circular RNAs (circRNAs), a class of non-coding RNAs (ncRNAs), are highly stable and ubiquitous molecules that exhibit tissue-specific expression. Accumulating evidence has shown that aberrant expression of circRNAs can play a role in the pathogenesis of several diseases. Rheumatic diseases are a varied group of autoimmune and inflammatory disorders affecting mainly the musculoskeletal system. Notably, circRNAs, which are essential immune system gene modulators, are strongly linked to the occurrence and progression of autoimmune disorders. Here, we present and discuss the current findings concerning the roles, implications and theragnostic potentials of circRNAs in common rheumatic diseases, including ankylosing spondylitis (AS), osteoarthritis (OA), osteoporosis (OP), rheumatoid arthritis (RA), systemic lupus erythematosus (SLE), Crohn's disease (CD), and gout. This review aims to provide new insights to support the development of novel diagnostic and therapeutic strategies for these disabling diseases.

Rheumatoid arthritis and non-coding RNAs; how to trigger inflammation

Rheumatoid arthritis (RA) is a systemic and chronic inflammatory disease categorized by continuous synovitis in the joints and systemic inflammatory responses that can cause lifelong disability. The major cause of RA is the dysregulation of the immune response. The development of RA disease includes multiplex association of several interleukins and cells, which leads to synovial cell growth, cartilage and bone damage. The primary stage of RA disease is related to the modification of both the innate and adaptive immune systems, which leads to the formation of autoantibodies. This process results in many damaged molecules and epitope spreading. Both the innate (e.g., dendritic cells, macrophages, and neutrophils) and acquired immune cells (e.g., T and B lymphocytes) will increase and continue the chronic inflammatory condition in the next stages of the RA disease. In recent years, non-coding RNAs have been proved as significant controllers of biological functions, especially immune cell expansion and reactions. Non-coding RNAs were primarily containing microRNA (miRNA), long non-coding RNA (lncRNA), and circular RNA (circRNA). Various studies confirmed non-coding RNAs as hopeful markers for diagnosing and curing RA. This review will describe and cover existing knowledge about RA pathogenesis, which might be favorable for discovering possible ncRNA markers for RA.

The Function and Therapeutic Potential of Circular RNA in Cardiovascular Diseases

Circular RNA (circRNA) has a closed-loop structure, and its 3' and 5' ends are directly covalently connected by reverse splicing, which is more stable than linear RNA. CircRNAs usually possess microRNA (miRNA) binding sites, which can bind miRNAs and inhibit miRNA function. Many studies have shown that circRNAs are involved in the processes of cell senescence, proliferation and apoptosis and a series of signalling pathways, playing an important role in the prevention and treatment of diseases. CircRNAs are potential biological diagnostic markers and therapeutic targets for cardiovascular diseases (CVDs). To identify biomarkers and potential effective therapeutic targets without toxicity for heart disease, we summarize the biogenesis, biology, characterization and functions of circRNAs in CVDs, hoping that this information will shed new light on the prevention and treatment of CVDs.

Circ_0088194 Regulates Proliferation, Migration, Apoptosis, and Inflammation by miR-30a-3p/ADAM10 Axis in Rheumatoid Arthritis Fibroblastic Synovial Cells

Dysregulation of circular RNAs (circRNAs) has been observed in multiple diseases including rheumatoid arthritis (RA), and we investigated the role of the circ_0088194/microRNA (miR)-30a-3p/a disintegrin and metalloproteinase 10 (ADAM10) axis in RA. Circ_0088194, miR-30a-3p, and ADAM10 contents in RA tissues and RA-fibroblast-like synoviocytes (RA-FLSs) were analyzed by real-time quantitative polymerase chain reaction (RT-qPCR) and western blot. Cell proliferation, migration, apoptosis, and inflammatory factor secretion of RA-FLSs were detected using 5-ethynyl-2'-deoxyuridine (EdU), wound healing assay, flow cytometry, and enzyme-linked immunosorbent assay (ELISA). Targeting relationship between miR-30a-3p and circ_0088194 or ADAM10 was validated by luciferase reporter system, RNA immunoprecipitation (RIP), and RNA pull-down assays. Circ_0088194 and ADAM10 levels were increased, while miR-30a-3p was decreased in RA tissues and RA-FLSs. Circ_0088194 knockdown suppressed the growth, migration, and inflammation of RA-FLSs, while the upregulation of circ_0088194 showed opposite effects. Circ_0088194 directly targeted miR-30a-3p, ADAM10 was a target of miR-30a-3p, and circ_0088194 regulated the expression of ADAM10 by sponging miR-30a-3p. MiR-30a-3p inhibition restored the inhibition effects of circ_0088194 knockdown or RA-FLSs. Moreover, miR-30a-3p re-expression repressed growth, migration, and inflammatory response in RA-FLSs, which were reversed by ADAM10 overexpression. Circ_0088194 acted on miR-30a-3p/ADAM10 axis to promote the proliferation, migration, and inflammatory response, and inhibit apoptosis in RA-FLSs.

Epigenetic Regulations in Autoimmunity and Cancer: from Basic Science to Translational Medicine

Epigenetics, as a discipline that aims to explain the differential expression of phenotypes arising from the same gene sequence and the heritability of epigenetic expression, has received much attention in medicine. Epigenetic mechanisms are constantly being discovered, including DNA methylation, histone modifications, noncoding RNAs and m6A. The immune system mainly achieves an immune response through the differentiation and functional expression of immune cells, in which epigenetic modification will have an important impact. Because of immune infiltration in the tumor microenvironment, immunotherapy has become a research hotspot in tumor therapy. Epigenetics plays an important role in autoimmune diseases and cancers through immunology. An increasing number of drugs targeting epigenetic mechanisms, such as DNA methyltransferase inhibitors, histone deacetylase inhibitors, and drug combinations, are being evaluated in clinical trials for the treatment of various cancers (including leukemia and osteosarcoma) and autoimmune diseases (systemic lupus erythematosus, rheumatoid arthritis, systemic sclerosis). This review summarizes the progress of epigenetic regulation for cancers and autoimmune diseases to date, shedding light on potential therapeutic strategies.

Circ_0044411 silencing protects infantile pneumonia from lipopolysaccharide-induced cell injury by sponging miR-141-3p to inhibit CCL16 expression

BACKGROUND

Circular RNA (circRNA) has been found to play an important role in the progression of many diseases, including infantile pneumonia. However, the role of circ_0044411 in infantile pneumonia progression is still unclear.

METHODS

MRC-5 cells were incubated with lipopolysaccharide (LPS) for 12 h to establish the in vitro cellular model for infantile pneumonia. Reverse transcription-quantitative polymerase chain reaction (RT-qPCR) was used to detect the levels of circ_0044411, miR-141-3p (micoRNA-141-3p) and CCL16 (CC motif chemokine ligand 16). Cell viability and proliferation was assessed by 3-(4, 5-dimethylthiazol-2-y1)-2, 5-diphenyl tetrazolium bromide (MTT) assay and 5-ethynyl-2'-deoxyuridine (EdU) assay. The levels of inflammatory factors IL-1β, IL-6 and TNF-α were determined by enzyme-linked immunosorbent assay kits. Cell apoptosis and caspase-3 activity were detected by flow cytometry analysis and caspase-3 activity assay kit. The target interaction was confirmed by dual-luciferase reporter assay, RNA immunoprecipitation assay and RNA pull-down assay.

RESULTS

Circ_0044411 was highly repressed in the serum of infantile pneumonia patients and LPS-induced MRC-5 cells. Circ_0044411 could promote the cell viability and proliferation, inhibit inflammatory response and apoptosis in LPS-induced MRC-5 cells. Circ_0044411 could serve as a sponge of miR-141-3p, and miR-141-3p could reverse the function of circ_0044411 on LPS-induced MRC-5 cell injury. In addition, miR-141-3p could target CCL16, and miR-141-3p could protect MRC-5 cells from LPS-induced cell injury by targeting CCL16. Furthermore, circ_0044411 sponged miR-141-3p to positively regulate CCL16 expression.

CONCLUSION

Circ_0044411 knockdown promoted cell viability and proliferation, inhibited inflammatory response and apoptosis by regulating miR-141-3p/CCL16 axis, indicating that circ_0044411 might be a potential therapeutic target for IP.

CircRNA_0075723 protects against pneumonia-induced sepsis through inhibiting macrophage pyroptosis by sponging miR-155-5p and regulating SHIP1 expression

Introduction

Circular RNAs (circRNAs) have been linked to regulate macrophage polarization and subsequent inflammation in sepsis. However, the underlying mechanism and the function of circRNAs in macrophage pyroptosis in pneumonia-induced sepsis are still unknown.

Methods

In this study, we screened the differentially expressed circRNAs among the healthy individuals, pneumonia patients without sepsis and pneumonia-induced sepsis patients in the plasma by RNA sequencing (RNA-seq). Then we evaluated macrophage pyroptosis in sepsis patients and in vitro LPS/nigericin activated THP-1 cells. The lentiviral recombinant vector for circ_0075723 overexpression (OE-circ_0075723) and circ_0075723 silence (sh-circ_0075723) were constructed and transfected into THP-1 cells to explore the potential mechanism of circ_0075723 involved in LPS/nigericin induced macrophage pyroptosis.

Results

We found circ_0075723, a novel circRNA that was significantly downregulated in pneumonia-induced sepsis patients compared to pneumonia patients without sepsis and healthy individuals. Meanwhile, pneumonia-induced sepsis patients exhibited activation of NLRP3 inflammasome and production of the pyroptosis-associated pro-inflammatory cytokines IL-1β and IL-18. circ_0075723 inhibited macrophage pyroptosis via sponging miR-155-5p which promoted SHIP1 expression directly. Besides, we found that circ_0075723 in macrophages promoted VE-cadherin expression in endothelial cells through inhibiting the release of NLRP3 inflammasome-related cytokines, IL-1β and IL-18, and protects endothelial cell integrity.

Discussion

Our findings propose a unique approach wherein circ_0075723 suppresses macrophage pyroptosis and inflammation in pneumonia-induced sepsis via sponging with miR-155-5p and promoting SHIP1 expression. These findings indicate that circRNAs could be used as possible potential diagnostic and therapeutic targets for pneumonia-induced sepsis.

An update on epigenetic regulation in autoimmune diseases

Autoimmune diseases (AIDs) generally manifest as chronic immune disorders characterized by significant heterogeneity and complex symptoms. The discordant incidence of AIDs between monozygotic twins guided people to attach importance to environmental factors. Epigenetics is one of the major ways to be influenced, some of them can even occur years before clinical diagnosis. With the advent of high-throughput omics times, the mysterious veil of epigenetic modification in AIDs has been gradually unraveled, and some progress has been made in utilizing it as indicators of diagnosis and disease activity. For example, the hypomethylated IFI44L promoter in diagnosing systematic lupus erythematosus (SLE). More recently, newly identified noncoding RNAs (ncRNAs), including long noncoding RNAs (lncRNAs) and circular RNAs (circRNAs), are also believed to be involved in the etiology of AIDs while the initial factor behind those epigenetic alterations can be diverse from metabolism to microbiota. Update and comprehensive insights into epigenetics in AIDs can help us understand the pathogenesis and further orchestrate it to benefit patients in the future. Therefore, we reviewed the latest epigenetic findings in SLE, rheumatoid arthritis (RA), Type 1 diabetes (T1D), systemic sclerosis (SSc) primarily from cellular levels.