Activation of RXR by bexarotene inhibits inflammatory conditions in human rheumatoid arthritis fibroblast‑like synoviocytes

Can pyroptosis be a new target in rheumatoid arthritis treatment?

Rheumatoid arthritis (RA) is a chronic systemic autoimmune disease of undefined etiology, with persistent synovial inflammation and destruction of articular cartilage and bone. Current clinical drugs for RA mainly include non-steroidal anti-inflammatory drugs (NSAIDs), glucocorticoids, disease modifying anti-rheumatic drugs (DMARDs) and so on, which can relieve patients' joint symptoms. If we want to have a complete cure for RA, there are still some limitations of these drugs. Therefore, we need to explore new mechanisms of RA to prevent and treat RA radically. Pyroptosis is a newly discovered programmed cell death (PCD) in recent years, which is characterized by the appearance of holes in cell membranes, cell swelling and rupture, and the release of intracellular pro-inflammatory factors into the extracellular space, resulting in a strong inflammatory response. The nature of pyroptosis is pro-inflammatory, and whether it is participating in the development of RA has attracted a wide interest among scholars. This review describes the discovery and mechanism of pyroptosis, the main therapeutic strategies for RA, and the role of pyroptosis in the mechanism of RA development. From the perspective of pyroptosis, the study of new mechanisms of RA may provide a potential target for the treatment of RA and the development of new drugs in the clinics.

Insights into the SARS-CoV-2-Mediated Alteration in the Stress Granule Protein Regulatory Networks in Humans

The rapidly and constantly evolving coronavirus, SARS-CoV-2, imposes a great threat to human health causing severe lung disease and significant mortality. Cytoplasmic stress granules (SGs) exert anti-viral activities due to their involvement in translation inhibition and innate immune signaling. SARS-CoV-2 sequesters important SG nucleator proteins and impairs SG formation, thus evading the host response for efficient viral replication. However, the significance of SGs in COVID-19 infection remains elusive. In this study, we utilize a protein-protein interaction network approach to systematically dissect the crosstalk of human post-translational regulatory networks governed by SG proteins due to SARS-CoV-2 infection. We uncovered that 116 human SG proteins directly interact with SARS-CoV-2 proteins and are involved in 430 different brain disorders including COVID-19. Further, we performed gene set enrichment analysis to identify the drugs against three important key SG proteins (DYNC1H1, DCTN1, and LMNA) and also looked for potential microRNAs (miRNAs) targeting these proteins. We identified bexarotene as a potential drug molecule and miRNAs, hsa-miR-615-3p, hsa-miR-221-3p, and hsa-miR-124-3p as potential candidates for the treatment of COVID-19 and associated manifestations.

Exploring the role of monocyte chemoattractant protein-1 in fibroblast-like synovial cells in rheumatoid arthritis

Background

Rheumatoid arthritis (RA) is a chronic systemic inflammatory disease with persistent synovitis. In the present study, the impact of monocyte chemoattractant protein-1 (MCP-1) was explored to determine methods for the diagnosis and treatment of RA.

Methods

First, fibroblast-like synoviocytes (FLSs) were obtained from a collagen-induced rat RA model. Next, MCP-1-overexpression plasmid and small interfering RNA were transfected into human and rat FLSs. Cell Counting Kit-8 (CCK-8), Transwell migration and flow cytometry assays were used to analyze cell proliferation, migration and apoptosis of FLSs following MCP-1 transfections, respectively. Furthermore, western blotting was used to analyze the expression levels of p-P38, p-PI3K, PI3K, CD31, VEGF, TNF-α and IL-β in FLSs following MCP-1 transfection. In addition, reverse transcription-quantitative PCR and ELISAs were used to analyze the expression levels of C-reactive protein (CRP), estrogen receptor, MCP-1 and pentraxin-3 in patients with clinical RA, followed by correlation analysis of clinical data. Finally, expression validation, diagnostic and protein-protein interaction (PPI) network analysis of MCP-1 were performed.

Results

MCP-1 promoted FLS proliferation and migration, and affected the apoptosis of FLSs. In addition, the expression levels of p-P38, p-PI3K, PI3K, CD31, VEGF, TNF-α and IL-β were also affected by MCP-1. In patients with clinical RA, the expression level of MCP-1 was increased. Moreover, CRP expression level was significantly up-regulated in RA. Clinically, MCP-1 was strongly correlated with tender joint count, swollen joint count, visual analog scale for general health and disease activity score 28 (DAS28)-MCP-1, and was moderately correlated with DAS28 and DAS28-CRP. PPI analysis showed that MCP-1 mainly interacted with other inflammatory cytokines.

Conclusion

In conclusion, MCP-1 may play a significant regulatory role in RA, and could be used as a measurement index of clinical RA activity.

Targeting BRF2 in Cancer Using Repurposed Drugs

Simple Summary

BRF2, a subunit of the RNA polymerase III transcription complex, is upregulated in a wide variety of cancers and is a potential therapeutic target; however, no effective drugs are available to target BRF2. The upregulation of BRF2 in cancer cells confers survival via the prevention of oxidative stress-induced apoptosis. In this manuscript, we report the identification of potential BRF2 inhibitors through in silico drug repurposing screening. We further characterized bexarotene as a hit compound for the development of selective BRF2 inhibitors and provide experimental validation to support the repurposing of this FDA-approved drug as an agent to reduce the cellular levels of ROS and consequent BRF2 expression in cancers with elevated levels of oxidative stress.

Abstract

The overexpression of BRF2, a selective subunit of RNA polymerase III, has been shown to be crucial in the development of several types of cancers, including breast cancer and lung squamous cell carcinoma. Predominantly, BRF2 acts as a central redox-sensing transcription factor (TF) and is involved in rescuing oxidative stress (OS)-induced apoptosis. Here, we showed a novel link between BRF2 and the DNA damage response. Due to the lack of BRF2-specific inhibitors, through virtual screening and molecular dynamics simulation, we identified potential drug candidates that interfere with BRF2-TATA-binding Protein (TBP)-DNA complex interactions based on binding energy, intermolecular, and torsional energy parameters. We experimentally tested bexarotene as a potential BRF2 inhibitor. We found that bexarotene (Bex) treatment resulted in a dramatic decline in oxidative stress and Tert-butylhydroquinone (tBHQ)-induced levels of BRF2 and consequently led to a decrease in the cellular proliferation of cancer cells which may in part be due to the drug pretreatment-induced reduction of ROS generated by the oxidizing agent. Our data thus provide the first experimental evidence that BRF2 is a novel player in the DNA damage response pathway and that bexarotene can be used as a potential inhibitor to treat cancers with the specific elevation of oxidative stress.

WNT Signaling Is a Key Player in Alzheimer's Disease

The cellular processes regulated by WNT signaling have been mainly studied during embryonic development and cancer. In the last two decades, the role of WNT in the adult central nervous system has been the focus of interest in our laboratory. In this chapter, we will be summarized β-catenin-dependent and -independent WNT pathways, then we will be revised WNT signaling function at the pre- and post-synaptic level. Concerning Alzheimer's disease (AD) initially, we found that WNT/β-catenin signaling activation exerts a neuroprotective mechanism against the amyloid β (Αβ) peptide toxicity. Later, we found that WNT/β-catenin participates in Tau phosphorylation and in learning and memory. In the last years, we demonstrated that WNT/β-catenin signaling is instrumental in the amyloid precursor protein (APP) processing and that WNT/β-catenin dysfunction results in Aβ production and aggregation. We highlight the importance of WNT/β-catenin signaling dysfunction in the onset of AD and propose that the loss of WNT/β-catenin signaling is a triggering factor of AD. The WNT pathway is therefore positioned as a therapeutic target for AD and could be a valid concept for improving AD therapy. We think that metabolism and inflammation will be relevant when defining future research in the context of WNT signaling and the neurodegeneration associated with AD.

The Landscape of Coronavirus Disease 2019 (COVID-19) and Integrated Analysis SARS-CoV-2 Receptors and Potential Inhibitors in Lung Adenocarcinoma Patients

The outbreak of novel coronavirus disease 2019 (COVID-19) has become the largest health threat worldwide, with more than 34.40 million positive cases and over 1.02 million deaths confirmed. In this study, we confirmed that significantly differentially expressed genes in COVID-19 patients were mainly involved in the regulation of immune and inflammation-related signaling pathways. It is worth noting that many infected COVID-19 patients have malignant tumors, and their prognosis is poor. To explore the susceptibility factors of cancer patients, we assessed the expression of ACE2, TMPRSS2, and the endocytic regulator AAK1 in lung adenocarcinoma (LUAD) patients and explored their effects on immune infiltration. We found that the expression of ACE2 and TMPRSS2 in LUAD patients was significantly increased, which may explain why LUAD patients are susceptible to SARS-CoV-2, and the patients with high-expression genes presented increased infiltration of immune cells such as B cells and CD4 T cells. In addition, we also identified miR-432-5p as a potential targeted molecule and bexarotene as a potential targeted drug of the three genes through bioinformatic analysis and further verified the anti-inflammatory effect of bexarotene, providing new ideas for the treatment of COVID-19.

The protective effects of dehydrocostus lactone against TNF-α-induced degeneration of extracellular matrix (ECM) in SW1353 cells

Osteoarthritis is a common joint disease that disrupts the lives of millions of people worldwide. To date, a safe and reliable treatment has not yet been announced. Excessive production of pro-inflammatory cytokines such as TNF-α plays an important role in the pathological development of OA. Dehydrocostus lactone (DHC) is a kind of sesquiterpene isolated from medicinal plants that has been demonstrated to play a protective role in inflammation and tumor formation. However, the effects of DHC in OA hasn't been reported before. In the present study, we investigated the antioxidant and protective effects of DHC in human chondrocytes against insult from tumor necrosis factor-α (TNF-α). We found that DHC inhibited oxidative stress by suppressing the production of reactive oxygen species (ROS) from TNF-α stimulation. Furthermore, DHC decreased the expression of pro-inflammatory cytokines induced by TNF-α, such as interleukin-1β (IL-1β) and interleukin-6 (IL-6). Importantly, DHC prevented the degradation of type II collagen and aggrecan, which are the main components of the extracellular matrix (ECM), by inhibiting the overexpression of matrix metalloproteinases (MMPs) and a disintegrin and metalloproteinase with a thrombospondin type 1 motif (ADAMTS) induced by TNF-α. Mechanistically, DHC ameliorated the inflammatory response and degeneration of the articular extracellular matrix (ECM) by suppressing nuclear factor-κB (NF-κB) activation. Our results reveal that DHC possesses a beneficial effect against TNF-α-mediated insult in human chondrocytes, implying a potential role for DHC in the treatment of osteoarthritis (OA).