ROS/TGF-β signal mediated accumulation of SOX4 in OA-FLS promotes cell senescence

Therapeutic potential of SOX family transcription factors in osteoarthritis

BACKGROUND

As the worldwide population ages, osteoarthritis has significantly increased. This musculoskeletal condition has become a pressing global health issue and thus, prevention and treatment of osteoarthritis have become the primary focus of domestic and international research. Scholarly investigations of the molecular mechanisms that are related to the occurrence and development of osteoarthritis have shed light on the pathological causes of this condition to a certain extent, providing a foundation for its prevention and treatment. However, further research is necessary to fully understand the critical role of the transcription factor SOX9 in chondrocyte differentiation and the development of osteoarthritis. As a result, there has been widespread interest in SOX transcription factors. While SOX9 has been utilized as a biomarker to indicate the occurrence and prognosis of osteoarthritis, investigations into other members of the SOX family and the development of targeted treatments around SOX9 are still required.

PURPOSE

This article considers the impact of the SOX protein on the development and inhibition of osteoarthritis and highlights the need for therapeutic approaches targeting SOX9, as supported by existing research.

RESULTS

SOX9 can contribute to the process of osteoarthritis through acetylation and ubiquitination modifications. The regulation of the WNT signalling pathway, Nrf2/ARE signalling pathway, NF-κB signalling pathway and SOX9 is implicated in the emergence of osteoarthritis. Non-coding RNA may play a role in the onset and progression of osteoarthritis by modulating various SOX family members, including SOX2, SOX4, SOX5, SOX6, SOX8, SOX9 and SOX11.

CONCLUSION

SOX9 has the capability of mitigating the onset and progression of osteoarthritis through means such as medication therapy, stem cell therapy, recombinant adeno-associated virus (rAAV) vector therapy, physical therapy and other approaches.

SOXs: Master architects of development and versatile emulators of oncogenesis

Transcription factors regulate a variety of events and maintain cellular homeostasis. Several transcription factors involved in embryonic development, has been shown to be closely associated with carcinogenesis when deregulated. Sry-like high mobility group box (SOX) proteins are potential transcription factors which are evolutionarily conserved. They regulate downstream genes to determine cell fate, via various signaling pathways and cellular processes essential for tissue and organ development. Dysregulation of SOXs has been reported to promote or suppress tumorigenesis by modulating cellular reprogramming, growth, proliferation, angiogenesis, metastasis, apoptosis, immune modulation, lineage plasticity, maintenance of the stem cell pool, therapy resistance and cancer relapse. This review provides a crucial understanding of the molecular mechanism by which SOXs play multifaceted roles in embryonic development and carcinogenesis. It also highlights their potential in advancing therapeutic strategies aimed at targeting SOXs and their downstream effectors in various malignancies.

Lactate-upregulated ARG2 expression induces cellular senescence in fibroblast-like synoviocytes of osteoarthritis via activating the mTOR/S6K1 signaling pathway

Cellular senescence was implicated in the pathogenesis of age-related diseases such as osteoarthritis (OA). Increasing evidence suggests that alterations in the OA joint microenvironment play a crucial role in the pathogenesis of OA. This study aims to establish a clear link between the impact of accumulated lactate on the senescence of fibroblast-like synoviocytes (FLS) within the OA microenvironment. OA models and models with intra-articular injection of lactate were established in rat models, histological analyses were performed. Human OA-FLS treated with lactate was analyzed by mRNA sequencing, senescence related experiments and underlying signaling pathway activation were comprehensively evaluated. This study confirmed that OA models and lactate-injection models exhibited higher synovitis scores. Enrichment analyses indicated dysregulated cell cycle and cellular senescence pathways in OA-FLS treated with lactate. Lactate significantly up-regulated arginase 2 (ARG2) expression and promoted OA-FLS senescence, including G1/S arrest, increased reactive oxygen species and β-galactosidase production, high expression of senescence-associated secretory phenotype factors, which could be attenuated by siRNA-Arg2. The ARG2-mTOR/S6K1 axis was identified as a potential signaling for lactate-induced OA-FLS senescence, and activated mTOR/S6K1 signaling could be reduced by siRNA-Arg2, rapamycin (mTOR inhibitor), and LY294002 (PI3K inhibitor). Our study provides novel targets and insights for OA therapies.

Polystyrene microplastics and di-2-ethylhexyl phthalate co-exposure: Implications for female reproductive health

Microplastics and phthalates are prevalent and emerging pollutants that pose a potential impact on human health. Previous studies suggest that both microplastics and phthalates can adversely affect the reproductive systems of humans and mammals. However, the combined impact of these pollutants on the female reproductive system remains unclear. Here we show the impacts of exposure to polystyrene microplastics (PS-MPs) and di-2-ethylhexyl phthalate (DEHP) on female Sprague-Dawley rats' reproductive systems. We find that co-exposure to PS-MPs and DEHP results in a marked increase in cystic and atretic follicles, oxidative stress, fibrosis, and dysregulation of serum sex hormone homeostasis in the ovaries of the rats. Proteomic analysis identified differentially expressed proteins that were predominantly enriched in signaling pathways related to fatty acid metabolism and tight junctions, regulated by transforming growth factor β1 (TGF-β1). We further confirm that co-exposure to DEHP and PS-MPs activates the TGF-β1/Smad3 signaling pathway, and inhibiting this pathway alleviates oxidative stress, hormonal dysregulation, and ovarian fibrosis. These results indicate that exposure to the combination of microplastics and phthalates leads to a significant increase in atretic follicles and may increase the risk of polycystic ovary syndrome (PCOS). Our study provides new insights into the reproductive toxicity effects of microplastics and DEHP exposure on female mammals, highlighting the potential link between environmental pollutants and the occurrence of PCOS. These findings highlight the need for comprehensive assessments of the reproductive health risks posed by microplastic pollution to women and contribute to the scientific basis for evaluating such risks.

Targeting PAR2-mediated inflammation in osteoarthritis: a comprehensive in vitro evaluation of oleocanthal's potential as a functional food intervention for chondrocyte protection and anti-inflammatory effects

BACKGROUND

Osteoarthritis (OA) is a prevalent degenerative joint disease characterized by chronic inflammation and progressive cartilage degradation, ultimately leading to joint dysfunction and disability. Oleocanthal (OC), a bioactive phenolic compound derived from extra virgin olive oil, has garnered significant attention due to its potent anti-inflammatory properties, which are comparable to those of non-steroidal anti-inflammatory drugs (NSAIDs). This study pioneers the investigation into the effects of OC on the Protease-Activated Receptor-2 (PAR-2) mediated inflammatory pathway in OA, aiming to validate its efficacy as a functional food-based therapeutic intervention.

METHODS

To simulate cartilage tissue in vitro, human bone marrow-derived mesenchymal stem cells (BMSCs) were differentiated into chondrocytes. An inflammatory OA-like environment was induced in these chondrocytes using lipopolysaccharide (LPS) to mimic the pathological conditions of OA. The therapeutic effects of OC were evaluated by treating these inflamed chondrocytes with various concentrations of OC. The study focused on assessing key inflammatory markers, catabolic enzymes, and mitochondrial function to elucidate the protective mechanisms of OC. Mitochondrial function, specifically mitochondrial membrane potential (ΔΨm), was assessed using Rhodamine 123 staining, a fluorescent dye that selectively accumulates in active mitochondria. The integrity of ΔΨm serves as an indicator of mitochondrial and bioenergetic function. Additionally, Western blotting was employed to analyze protein expression levels, while real-time polymerase chain reaction (RT-PCR) was used to quantify gene expression of inflammatory cytokines and catabolic enzymes. Flow cytometry was utilized to measure cell viability and apoptosis, providing a comprehensive evaluation of OC's therapeutic effects on chondrocytes.

RESULTS

The results demonstrated that OC significantly downregulated PAR-2 expression in a dose-dependent manner, leading to a substantial reduction in pro-inflammatory cytokines, including TNF-α, IL-1β, and MCP-1. Furthermore, OC attenuated the expression of catabolic markers such as SOX4 and ADAMTS5, which are critically involved in cartilage matrix degradation. Importantly, OC was found to preserve mitochondrial membrane potential (ΔΨm) in chondrocytes subjected to inflammatory stress, as evidenced by Rhodamine 123 staining, indicating a protective effect on cellular bioenergetics. Additionally, OC modulated the Receptor Activator of Nuclear Factor Kappa-Β Ligand (RANKL)/Receptor Activator of Nuclear Factor Kappa-Β (RANK) pathway, suggesting a broader therapeutic action against the multifactorial pathogenesis of OA.

CONCLUSIONS

This study is the first to elucidate the modulatory effects of OC on the PAR-2 mediated inflammatory pathway in OA, revealing its potential as a multifaceted therapeutic agent that not only mitigates inflammation but also protects cartilage integrity. The preservation of mitochondrial function and modulation of the RANKL/RANK pathway further underscores OC's comprehensive therapeutic potential in counteracting the complex pathogenesis of OA. These findings position OC as a promising candidate for integration into nutritional interventions aimed at managing OA. However, further research is warranted to fully explore OC's therapeutic potential across different stages of OA and its long-term effects in musculoskeletal disorders.

Polystyrene nanoplastics exposure causes erectile dysfunction in rats

Polystyrene nanoplastics (PS-NPs), emerging and increasingly pervasive environmental contaminants, have the potential to cause persistent harm to organisms. Although previous reports have documented local accumulation and adverse effects in a variety of major organs after PS-NPs exposure, the impact of PS-NPs exposure on erectile function remains unexplored. Herein, we established a rat model of oral exposure to 100 nm PS-NPs for 28 days. To determine the best dose range of PS-NPs, we designed both low-dose and high-dose PS-NPs groups, which correspond to the minimum and maximum human intake doses, respectively. The findings indicated that PS-NPs could accumulate within the corpus cavernosum and high dose but not low dose of PS-NPs triggered erectile dysfunction. Moreover, the toxicological effects of PS-NPs on erectile function include fibrosis in the corpus cavernous, endothelial dysfunction, reduction in testosterone levels, elevated oxidative stress and apoptosis. Overall, this study revealed that PS-NPs exposure can cause erectile dysfunction via multiple ways, which provided new insights into the toxicity of PS-NPs.

Acetyl-11-keto-β-boswellic acid restrains the progression of synovitis in osteoarthritis via the Nrf2/HO-1 pathway

Synovial inflammation plays a key role in osteoarthritis (OA) pathogenesis. Fibroblast-like synoviocytes (FLSs) represent a distinct cell subpopulation within the synovium, and their unique phenotypic alterations are considered significant contributors to inflammation and fibrotic responses. The underlying mechanism by which acetyl-11-keto-β-boswellic acid (AKBA) modulates FLS activation remains unclear. This study aims to assess the beneficial effects of AKBA through both in vitro and in vivo investigations. Network pharmacology evaluation is used to identify potential targets of AKBA in OA. We evaluate the effects of AKBA on FLSs activation in vitro and the regulatory role of AKBA on the Nrf2/HO-1 signaling pathway. ML385 (an Nrf2 inhibitor) is used to verify the binding of AKBA to its target in FLSs. We validate the in vivo efficacy of AKBA in alleviating OA using anterior cruciate ligament transection and destabilization of the medial meniscus (ACLT+DMM) in a rat model. Network pharmacological analysis reveals the potential effect of AKBA on OA. AKBA effectively attenuates lipopolysaccharide (LPS)-induced abnormal migration and invasion and the production of inflammatory mediators, matrix metalloproteinases (MMPs), and reactive oxygen species (ROS) in FLSs, contributing to the restoration of the synovial microenvironment. After treatment with ML385, the effect of AKBA on FLSs is reversed. In vivo studies demonstrate that AKBA mitigates synovial inflammation and fibrotic responses induced by ACLT+DMM in rats via activation of the Nrf2/HO-1 axis. AKBA exhibits theoretical potential for alleviating OA progression through the Nrf2/HO-1 pathway and represents a viable therapeutic candidate for this patient population.

Bibliometric study and visualization of cellular senescence associated with osteoarthritis from 2009 to 2023

BACKGROUND

Osteoarthritis is a common degenerative joint disease that is highly prevalent in the elderly population. Along with the occurrence of sports injuries, osteoarthritis is gradually showing a younger trend. Osteoarthritis has many causative factors, and its pathogenesis is currently unknown. Cellular senescence is a stable form of cell cycle arrest exhibited by cells in response to external stimuli and plays a role in a variety of diseases. And it is only in the last decade or so that cellular senescence has gradually become cross-linked with osteoarthritis. However, there is no comprehensive bibliometric analysis in this field. The aim of this study is to present the current status and research hotspots of cellular senescence in the field of osteoarthritis, and to predict the future trends of cellular senescence in osteoarthritis research from a bibliometric perspective.

METHODS

This study included 298 records of cellular senescence associated with osteoarthritis from 2009 to 2023, with data from the Web of Science Core Collection database. CiteSpace, Scimago Graphica software, VOSviewer, and the R package "bibliometrix" software were used to analyze regions, institutions, journals, authors, and keywords to predict recent trends in cellular senescence related to osteoarthritis research.

RESULTS

The number of publications related to cellular senescence associated with osteoarthritis is increasing year by year. China and the United States contribute more than 70% of the publications and are the mainstay of research in this field. Central South University is the most active institution with the largest number of publications. International Journal of Molecular Sciences is the most popular journal in the field with the largest number of publications, while Osteoarthritis and Cartilage is the most cited journal. Loeser, Richard F. is not only the most prolific author, but also the most frequently cited author, contributing greatly to the field.

CONCLUSION

In the last decade or so, this is the first bibliometric study that systematically describes the current status and development trend of research on cellular senescence associated with osteoarthritis. The study comprehensively and systematically summarizes and concludes the research hotspots and development trends, providing valuable references for researchers in this field.

SOX4 silencing alleviates renal injury in rats with acute renal failure by inhibiting the NF-κB signaling pathway and reducing apoptosis and oxidative stress

Acute renal failure (ARF) is a huge threat to the lives of most patients in intensive care units, and there is currently no satisfactory treatment strategy. SRY-box transcription factor 4 (SOX4) plays a key role in the development of various diseases, but its effect on ARF is unknown. Therefore, this study aimed to explore the relationship between SOX4 and ARF. Blood samples were collected from 20 ARF patients and 20 healthy volunteers. We also established an ARF rat model by excising the right kidney and ligating the left renal artery, and SOX4 knockdown in ARF rats was achieved down by means of lentiviral infection. Subsequently, we used quantitative polymerase chain reaction and western bolt assays to detect the expression levels of SOX4 and nuclear factor-κB (NF-κB) signaling pathway-related proteins in human blood or rat renal tissue and hematoxylin and eosin and terminal deoxynucleotidyl transferase (TdT) 2'-deoxyuridine 5'-triphosphate (dUTP) nick-end labeling staining to observe the pathological changes and apoptosis of renal tissue. Enzyme-linked immunosorbent assay and biochemical kits were used to measure the levels of renal function-related indicators (blood urea nitrogen, creatinine, and neutrophil gelatinase-associated lipocalin) and inflammatory factors (interleukin [IL]-1β, IL-6, and tumor necrosis factor-alpha), as well as changes in oxidative stress-related indicators (malondialdehyde [MDA], superoxide dismutase [SOD], and reactive oxygen species [ROS]) in rat serum. SOX4 expression levels in blood samples from ARF patients and renal tissue from ARF rats were significantly higher compared with those in healthy volunteers and control rats, respectively. ARF model rats displayed the typical ARF phenotype, while SOX4 silencing significantly improved pathological injury and apoptosis of renal tissue in ARF rats. Moreover, SOX4 silencing significantly inhibited increased levels of renal function-related indicators and inflammatory factors and reduced the level of excessive oxidative stress (MDA and ROS were upregulated, and SOD was downregulated) in ARF rats. SOX4 also reduced the activity of the NF-κB signaling pathway in ARF samples. Thus, SOX4 knockdown may reduce oxidative stress, the inflammatory response, and apoptosis by reducing the activity of the NF-κB signaling pathway, thereby improving renal injury in ARF rats.

DNA methylation clocks for clawed frogs reveal evolutionary conservation of epigenetic aging

To address how conserved DNA methylation-based epigenetic aging is in diverse branches of the tree of life, we generated DNA methylation data from African clawed frogs (Xenopus laevis) and Western clawed frogs (Xenopus tropicalis) and built multiple epigenetic clocks. Dual species clocks were developed that apply to both humans and frogs (human-clawed frog clocks), supporting that epigenetic aging processes are evolutionary conserved outside mammals. Highly conserved positively age-related CpGs are located in neural-developmental genes such as uncx, tfap2d as well as nr4a2 implicated in age-associated disease. We conclude that signatures of epigenetic aging are evolutionary conserved between frogs and mammals and that the associated genes relate to neural processes, altogether opening opportunities to employ Xenopus as a model organism to study aging.

Cholesterol-induced HRD1 reduction accelerates vascular smooth muscle cell senescence via stimulation of endoplasmic reticulum stress-induced reactive oxygen species

Senescence of vascular smooth muscle cells (VSMCs) is a key contributor to plaque vulnerability in atherosclerosis (AS), which is affected by endoplasmic reticulum (ER) stress and reactive oxygen species (ROS) production. However, the crosstalk between ER stress and ROS production in the pathogenesis of VSMC senescence remains to be elucidated. ER-associated degradation (ERAD) is a complex process that clears unfolded or misfolded proteins to maintain ER homeostasis. HRD1 is the major E3 ligase in mammalian ERAD machineries that catalyzes ubiquitin conjugation to the unfolded or misfolded proteins for degradation. Our results showed that HRD1 protein levels were reduced in human AS plaques and aortic roots from ApoE-/- mice fed with high-fat diet (HFD), along with the increased ER stress response. Exposure to cholesterol in VSMCs activated inflammatory signaling and induced senescence, while reduced HRD1 protein expression. CRISPR Cas9-mediated HRD1 knockout (KO) exacerbated cholesterol- and thapsigargin-induced cell senescence. Inhibiting ER stress with 4-PBA (4-Phenylbutyric acid) partially reversed the ROS production and cell senescence induced by HRD1 deficiency in VSMCs, suggesting that ER stress alone could be sufficient to induce ROS production and senescence in VSMCs. Besides, HRD1 deficiency led to mitochondrial dysfunction, and reducing ROS production from impaired mitochondria partly reversed HRD1 deficiency-induced cell senescence. Finally, we showed that the overexpression of HDR1 reversed cholesterol-induced ER stress, ROS production, and cellular senescence in VSMCs. Our findings indicate that HRD1 protects against senescence by maintaining ER homeostasis and mitochondrial functionality. Thus, targeting HRD1 function may help to mitigate VSMC senescence and prevent vascular aging related diseases. TRIAL REGISTRATION: A real-world study based on the discussion of primary and secondary prevention strategies for coronary heart disease, URL:https://www.clinicaltrials.gov, the trial registration number is [2022]-02-121-01.

Acetylshikonin promoting PI3K/Akt pathway and inhibiting SOX4 expression to delay intervertebral disc degeneration and low back pain

This study investigated the molecular mechanism by which acetylshikonin inhibits SOX4 expression via the PI3K/Akt pathway to delay intervertebral disc degeneration (IVDD) and low back pain (LBP). Bulk RNA-seq, RT-qPCR, Western blot analysis, immunohistochemical staining, small interfering RNA (siSOX4), lentivirus (lentiv-SOX4hi ), and imaging techniques were used to assess SOX4 expression and validate its upstream regulatory pathway. Acetylshikonin and siSOX4 were injected into the IVD to measure IVDD. SOX4 expression significantly increased in degenerated IVD tissues. TNF-α increased SOX4 expression and apoptosis-related proteins in nucleus pulposus cells (NPCs). siSOX4 reduced TNF-α-induced NPCs apoptosis, while Lentiv-SOX4hi increased it. The PI3K/Akt pathway was significantly correlated with SOX4, and acetylshikonin upregulated PI3K/Akt pathway while inhibiting SOX4 expression. In the anterior puncture IVDD mouse model, SOX4 expression was upregulated, and acetylshikonin and siSOX4 delayed IVDD-induced LBP. Acetylshikonin delays IVDD-induced LBP by inhibiting SOX4 expression through the PI3K/Akt pathway. These findings offer potential therapeutic targets for future treatments.

Nanomaterial-based Reactive Oxygen Species Scavengers for Osteoarthritis Therapy

Reactive oxygen species (ROS) play distinct but important roles in physiological and pathophysiological processes. Recent studies on osteoarthritis (OA) have suggested that ROS plays a crucial role in its development and progression, serving as key mediators in the degradation of the extracellular matrix, mitochondrial dysfunction, chondrocyte apoptosis, and OA progression. With the continuous development of nanomaterial technology, the ROS-scavenging ability and antioxidant effects of nanomaterials are being explored, with promising results already achieved in OA treatment. However, current research on nanomaterials as ROS scavengers for OA is relatively non-uniform and includes both inorganic and functionalized organic nanomaterials. Although the therapeutic efficacy of nanomaterials has been reported to be conclusive, there is still no uniformity in the timing and potential of their use in clinical practice. This paper reviews the nanomaterials currently used as ROS scavengers for OA treatment, along with their mechanisms of action, with the aim of providing a reference and direction for similar studies, and ultimately promoting the early clinical use of nanomaterials for OA treatment. STATEMENT OF SIGNIFICANCE: Reactive oxygen species (ROS) play an important role in the pathogenesis of osteoarthritis (OA). Nanomaterials serving as promising ROS scavengers have gained increasing attention in recent years. This review provides a comprehensive overview of ROS production and regulation, as well as their role in OA pathogenesis. Furthermore, this review highlights the applications of various types of nanomaterials as ROS scavengers in OA treatment and their mechanisms of action. Finally, the challenges and future prospects of nanomaterial-based ROS scavengers in OA therapy are discussed.

NFIXing Cancer: The Role of NFIX in Oxidative Stress Response and Cell Fate

NFIX, a member of the nuclear factor I (NFI) family of transcription factors, is known to be involved in muscle and central nervous system embryonic development. However, its expression in adults is limited. Similar to other developmental transcription factors, NFIX has been found to be altered in tumors, often promoting pro-tumorigenic functions, such as leading to proliferation, differentiation, and migration. However, some studies suggest that NFIX can also have a tumor suppressor role, indicating a complex and cancer-type dependent role of NFIX. This complexity may be linked to the multiple processes at play in regulating NFIX, which include transcriptional, post-transcriptional, and post-translational processes. Moreover, other features of NFIX, including its ability to interact with different NFI members to form homodimers or heterodimers, therefore allowing the transcription of different target genes, and its ability to sense oxidative stress, can also modulate its function. In this review, we examine different aspects of NFIX regulation, first in development and then in cancer, highlighting the important role of NFIX in oxidative stress and cell fate regulation in tumors. Moreover, we propose different mechanisms through which oxidative stress regulates NFIX transcription and function, underlining NFIX as a key factor for tumorigenesis.

SOXC Transcription Factors as Diagnostic Biomarkers and Therapeutic Targets for Arthritis

Osteoarthritis (OA) and rheumatoid arthritis (RA) are two common disorders that disrupt the quality of life of millions of people. These two chronic diseases cause damage to the joint cartilage and surrounding tissues of more than 220 million people worldwide. Sex-determining region Y-related (SRY) high-mobility group (HMG) box C, SOXC, is a superfamily of transcription factors that have been recently shown to be involved in various physiological and pathological processes. These include embryonic development, cell differentiation, fate determination, and autoimmune diseases, as well as carcinogenesis and tumor progression. The SOXC superfamily includes SOX4, SOX11, and SOX12, all have a similar DNA-binding domain, i.e., HMG. Herein, we summarize the current knowledge about the role of SOXC transcription factors during arthritis progression and their potential utilization as diagnostic biomarkers and therapeutic targets. The involved mechanistic processes and signaling molecules are discussed. SOX12 appears to have no role in arthritis, however SOX11 is dysregulated and promotes arthritic progression according to some studies but supports joint maintenance and protects cartilage and bone cells according to others. On the other hand, SOX4 upregulation during OA and RA was documented in almost all studies including preclinical and clinical models. Molecular details have indicated that SOX4 can autoregulate its own expression besides regulating the expression of SOX11, a characteristic associated with the transcription factors that protects their abundance and activity. From analyzing the currently available data, SOX4 seems to be a potential diagnostic biomarker and therapeutic target of arthritis.

Polystyrene nanoplastics exacerbate lipopolysaccharide-induced myocardial fibrosis and autophagy in mice via ROS/TGF-β1/Smad

Polystyrene nanoplastics (PS NPs) contamination is a serious problem for human and animal health. Excessive exposure to PS NPs can affect the structure and function of the heart. And lipopolysaccharide (LPS) induces myocardial damage, leading to myocardial fibrosis (MF). To investigate whether PS NPs exacerbate LPS-induced myocardial autophagy and fibrosis, we established in vivo and in vitro models of PS NPs/LPS exposure alone and in combination. We found that PS NPs/LPS exposure disrupts myocardial structure, significantly increases reactive oxygen species (ROS), triggers oxidative stress, promotes TGF-β1/Smad pathway activation, and leads to elevated levels of fibrotic proteins and collagen. Meanwhile, activation of AMPK/mTOR/ULK1 signaling pathway induced autophagy onset, and combined exposure of PS NPs/LPS exacerbated MF and autophagy. H9C2 cells were used for in vitro experiments, and the experimental results showed that the addition of TGF-β receptor inhibitor LY2109761 to the exposed group not only inhibited the upregulation of fibrotic genes but also effectively reduced the expression of autophagic signals, indicating that combined exposure of PS NPs and LPS mediates and regulates cardiac autophagy through TGF-β1. The above results suggest that PS NPs exacerbate LPS-induced MF and autophagy in mice via ROS/TGF-β1/Smad. Our study provides some new evidence to clarify the potential mechanisms of PS NPs-induced cardiotoxicity.

SOX4 and RELA Function as Transcriptional Partners to Regulate the Expression of TNF- Responsive Genes in Fibroblast-Like Synoviocytes

SOX4 belongs to the group C of the SOX transcription factor family. It is a critical mediator of tumor necrosis factor alpha (TNF)-induced transformation of fibroblast-like s-ynoviocytes (FLS) in arthritis. In this study we investigated the genome wide association between the DNA binding and transcriptional activities of SOX4 and the NF-kappaB signaling transcription factor RELA/p65 downstream of TNF signaling. We used ChIP-seq assays in mouse FLS to compare the global DNA binding profiles of SOX4 and RELA. RNA-seq of TNF-induced wildtype and SoxC-knockout FLS was used to identify the SOX4-dependent and independent aspects of the TNF-regulated transcriptome. We found that SOX4 and RELA physically interact with each other on the chromatin. Interestingly, ChIP-seq assays revealed that 70.4% of SOX4 peak summits were within 50bp of the RELA peak summits suggesting that both proteins bind in close-proximity on regulatory sequences, enabling them to co-operatively regulate gene expression. By integrating the ChIP-seq results with RNA-seq from SoxC-knockout FLS we identified a set of TNF-responsive genes that are targets of the RELA-SOX4 transcriptional complex. These TNF-responsive and RELA-SOX4-depenedent genes included inflammation mediators, histone remodeling enzymes and components of the AP-1 signaling pathway. We also identified an autoregulatory mode of SoxC gene expression that involves a TNF-mediated switch from RELA binding to SOX4 binding in the 3' UTR of Sox4 and Sox11 genes. In conclusion, our results show that SOX4 and RELA together orchestrate a multimodal regulation of gene expression downstream of TNF signaling. Their interdependent activities play a pivotal role in the transformation of FLS in arthritis and in the inflammatory pathology of diverse tissues where RELA and SOX4 are co-expressed.