ATF6α promotes prostate cancer progression by enhancing PLA2G4A-mediated arachidonic acid metabolism and protecting tumor cells against ferroptosis.

BACKGROUND: Despite the clinical success of androgen receptor (AR)-targeted therapies, prostate cancer (PCa) inevitably progresses to castration-resistant prostate cancer (CRPC). Transcription factor 6 α (ATF6α), an effector of the unfolded protein response (UPR) that modulates the cellular response to endoplasmic reticulum (ER) stress, has been linked to tumor development, metastasis, and relapse. However, the role of ATF6α in CRPC remains unclear. METHODS: The effect of ATF6α on the CRPC-like phenotype in PCa cells was evaluated by 3-(4,5-dimethylthiazol-2-yl)-5-(3-carb-Oxymethoxyphenyl)-2-(4-sulfophenyl)-2H-tetrazolium inner salt (MTS), 5-Bromo-2-deoxyUridine (BrdU) incorporation analysis, and cell death assay. Mechanistically, bioinformatic analysis was utilized to evaluate the potential of PLA2G4A as the target of ATF6α. Moreover, Western blot analysis, real-time polymerase chain reaction, chromatin immunoprecipitation, arachidonic acid (AA), and prostaglandin E2 (PGE2) assays were performed to identify the regulatory effect of ATF6α on PLA2G4A. RESULTS: In this study, we found that the increase of ATF6α expression in response to androgen deprivation generates PCa cells with a CRPC-like phenotype. PCa cells with high levels of ATF6α expression are resistant to ferroptosis, and genetic and pharmacological inhibition of ATF6α could, therefore, promote the ferroptotic death of tumor cells and delay PCa progression. Molecular analyses linked ATF6α regulation of ferroptosis to the PLA2G4A-mediated release of AA and the resulting increase in PGE2 production, the latter of which acts as an antiferroptotic factor. CONCLUSIONS: This study defines ATF6α as a novel antiferroptotic regulator that exacerbates PCa progression. In addition, our data establish ATF6α-PLA2G4A signaling as an important pathological pathway in PCa, and targeting this pathway may be a novel treatment strategy.

Preclinical evaluation and pilot clinical study of [18F]AlF-NOTA-FAPI-04 for PET imaging of rheumatoid arthritis.

PURPOSE: Fibroblast-like synoviocytes (FLSs) are key effector cells in the inflamed joints of patients with rheumatoid arthritis (RA). Previous studies have suggested that fibroblast activation protein (FAP) is highly expressed in RA-derived FLSs and is a specific marker of activated RA FLSs. In this study, we developed aluminum-[18F]-labeled 1,4,7-triazacyclononane-N,N',N″-triacetic acid-conjugated FAP inhibitor 04 ([18F]AlF-NOTA-FAPI-04) to image RA-FLSs in vitro and arthritic joints in collagen-induced arthritis (CIA) mice and RA patients. METHODS: RA FLSs and NIH3T3 cells transfected with FAP were used to perform in vitro-binding studies. Biodistribution was conducted in normal DBA1 mice. Collagen-induced arthritis (CIA) models with different arthritis scores were subjected to [18F]AlF-NOTA-FAPI-04 and 18F-FDG PET imaging. Histological examinations were performed to evaluate FAP expression and Cy3 dye-labeled FAPI-04(Cy3-FAPI-04) uptake. Blocking studies with excess unlabeled FAPI-04 in CIA mice and NIH3T3 xenografts in immunocompromised mice were used to evaluate the binding specificity of [18F]AlF-NOTA-FAPI-04. Additionally, [18F]AlF-NOTA-FAPI-04 PET imaging was performed on two RA patients. RESULTS: The binding of [18F]AlF-NOTA-FAPI-04 increased significantly in RA FLSs and NIH3T3 cells overexpressing FAP compared to their parental controls (FAP-GFP-NIH3T3 vs. GFP-NIH3T3, 2.40 ± 0.078 vs. 0.297 ± 0.05% AD/105 cells; RA FLSs vs. OA FLSs, 1.54 ± 0.064 vs. 0.343 ± 0.056% AD/105 cells). Compared to 18F-FDG imaging, [18F]AlF-NOTA-FAPI-04 showed high uptake in inflamed joints in the early stage of arthritis, which was positively correlated with the arthritic scores (Pearson r=0.834, P<0.001). In addition, the binding of [18F]AlF-NOTA-FAPI-04 to cells with high FAP expression and the uptake of [18F]AlF-NOTA-FAPI-04 in arthritic joints both could be blocked by excessive unlabeled FAPI-04. Fluorescent staining showed that the intensity of Cy3-FAPI-04 binding to FAP increased accordingly as the expression of FAP protein increased in cells and tissue sections. Furthermore, the uptake of [18F]AlF-NOTA-FAPI-04 in FAP-GFP-NIH3T3 xenografts was significantly higher than that in GFP-NIH3T3 xenograft (35.44 ± 4.27 vs 7.92 ± 1.83% ID/mL). Finally, [18F]AlF-NOTA-FAPI-04 PET/CT imaging in RA patients revealed nonphysiologically high tracer uptake in the synovium of arthritic joints. CONCLUSION: [18F]AlF-NOTA-FAPI-04 is a promising radiotracer for imaging RA FLSs and could potentially complement the current noninvasive diagnostic parameters.

Investigation into the correlation between humanistic care ability and emotional intelligence of hospital staff.

BACKGROUND: There are different degrees of flaws in the knowledge structure of humanistic medicine of medical staff. The level of emotional intelligence of medical staff affects their career development as well as their relationship with patients. Currently, the research on humanistic care ability (HCA) and emotional intelligence of medical staff in China and other countries is rare. This study aimed to investigate the correlation between the level of HCA and level of emotional intelligence of the whole hospital staff. METHODS: The questionnaire survey employed contained self-designed questions on the hospital staff members' socio-demographic background, Caring Ability Inventory, and Wong and Law Emotional Intelligence Scale. The survey was conducted with the staff of West China Second University Hospital, Sichuan University in April 2020. RESULTS: The hospital staff's average CAI score was 197.77 ± 20.30, and their average WLEIS score was 84.21 ± 13.48. The CAI and WLEIS scores of the hospital staff who chose their college majors on their own interests were higher than those who chose their majors for other reasons (employability, suggestions from family or others, etc.). The CAI and WLEIS scores of the hospital staff who had received more comprehensive and in-depth humanistic care training were higher than those who did not. The CAI score of the hospital staff who had participated in volunteer service activities was higher than those who did not. The WLEIS score of the Pediatrics Department staff was higher than that of the Outpatient and Emergency Department staff, and the difference was statistically significant (P < 0.05). The scores of emotional intelligence, self-emotion assessment and expression, self-emotion management, self-emotion utilization, emotion recognition of others, and HCA of the hospital staff were positively correlated (P < 0.001). CONCLUSION: There were different levels of development of internal factors of emotional intelligence among the hospital staff, and their humanistic care ability was at a low level. Emotional intelligence was positively correlated to humanistic care ability. The findings suggest in-service training and education by healthcare institutions to enhance healthcare staff's emotional intelligence for promoting the general health of the population.

DRB2 Modulates Leaf Rolling by Regulating Accumulation of MicroRNAs Related to Leaf Development in Rice.

As an important agronomic trait in rice (Oryza sativa), moderate leaf rolling helps to maintain the erectness of leaves and minimize shadowing between leaves, leading to improved photosynthetic efficiency and grain yield. However, the molecular mechanisms underlying rice leaf rolling still need to be elucidated. Here, we isolated a rice mutant, rl89, showing adaxially rolled leaf phenotype due to decreased number and size of bulliform cells. We confirmed that the rl89 phenotypes were caused by a single nucleotide substitution in OsDRB2 (LOC_Os10g33970) gene encoding DOUBLE-STRANDED RNA-BINDING2. This gene was constitutively expressed, and its encoded protein was localized to both nucleus and cytoplasm. Yeast two-hybrid assay showed that OsDRB2 could interact with DICER-LIKE1 (DCL1) and OsDRB1-2 respectively. qRT-PCR analysis of 29 related genes suggested that defects of the OsDRB2-miR166-OsHBs pathway could play an important role in formation of the rolled leaf phenotype of rl89, in which OsDRB2 mutation reduced miR166 accumulation, resulting in elevated expressions of the class III homeodomain-leucine zipper genes (such as OsHB1, 3 and 5) involved in leaf polarity and/or morphology development. Moreover, OsDRB2 mutation also reduced accumulation of miR160, miR319, miR390, and miR396, which could cause the abnormal leaf development in rl89 by regulating expressions of their target genes related to leaf development.

A lil3 chlp double mutant with exclusive accumulation of geranylgeranyl chlorophyll displays a lethal phenotype in rice.

BACKGROUND: Phytyl residues are the common side chains of chlorophyll (Chl) and tocopherols. Geranylgeranyl reductase (GGR), which is encoded by CHLP gene, is responsible for phytyl biosynthesis. The light-harvesting like protein LIL3 was suggested to be required for stability of GGR and protochlorophyllide oxidoreductase in Arabidopsis. RESULTS: In this study, we isolated a yellow-green leaf mutant, 637ys, in rice (Oryza sativa). The mutant accumulated majority of Chls with unsaturated geranylgeraniol side chains and displayed a yellow-green leaf phenotype through the whole growth period. The development of chloroplasts was suppressed, and the major agronomic traits, especially No. of productive panicles per plant and of spikelets per panicle, dramatically decreased in 637ys. Besides, the mutant exhibited to be sensitive to light intensity and deficiency of tocopherols without obvious alteration in tocotrienols in leaves and grains. Map-based cloning and complementation experiment demonstrated that a point mutation on the OsLIL3 gene accounted for the mutant phenotype of 637ys. OsLIL3 is mainly expressed in green tissues, and its encoded protein is targeted to the chloroplast. Furthermore, the 637ys 502ys (lil3 chlp) double mutant exclusively accumulated geranylgeranyl Chl and exhibited lethality at the three-leaf stage. CONCLUSIONS: We identified the OsLIL3 gene through a map-based cloning approach. Meanwhile, we demonstrated that OsLIL3 is of extreme importance to the function of OsGGR, and that the complete replacement of phytyl side chain of chlorophyll by geranylgeranyl chain could be fatal to plant survival in rice.

CD109 regulates the inflammatory response and is required for the pathogenesis of rheumatoid arthritis.

OBJECTIVE: The aim of this study was to investigate the role of CD109 in rheumatoid arthritis (RA) fibroblast-like synoviocytes (FLSs) and to evaluate its potential as a therapeutic target. METHODS: CD109 expression was examined in synovial tissues and FLSs from RA patients and collagen-induced arthritis (CIA) model mice. CD109-deficient mice were developed to evaluate the severity of CIA. Small interfering RNAs and a neutralising antibody against CD109 (anti-CD109) were designed for functional or treatment studies in RA FLSs and CIA. RESULTS: CD109 was found to be abundantly expressed in the synovial tissues from RA patients and CIA mice. CD109 expression in RA FLSs was upregulated by inflammatory stimuli, such as interleukin-1ß and tumour necrosis factor-α. Silencing of CD109 or anti-CD109 treatment reduced proinflammatory factor production, cell migration, invasion, chemoattractive potential and osteoclast differentiation, thereby reducing the deleterious inflammatory response of RA FLSs in vitro. Mice lacking CD109 were protected against arthritis in the CIA model. Anti-CD109 treatment prevented the onset and ameliorated the severity of CIA lesions. CONCLUSION: Our study uncovers an antiarthritic role for CD109 and suggests that CD109 inhibition might serve as a promising novel therapeutic strategy for RA.

A Single Nucleotide Mutation of the IspE Gene Participating in the MEP Pathway for Isoprenoid Biosynthesis Causes a Green-Revertible Yellow Leaf Phenotype in Rice.

Plant isoprenoids are dependent on two independent pathways, the cytosolic mevalonate (MVA) pathway and the plastidic methylerythritol phosphate (MEP) pathway. IspE is one of seven known enzymes in the MEP pathway. Currently, no IspE gene has been identified in rice. In addition, no virescent mutants have been reported to result from a gene mutation affecting the MEP pathway. In this study, we isolated a green-revertible yellow leaf mutant gry340 in rice. The mutant exhibited a reduced level of photosynthetic pigments, and an arrested development of chloroplasts and mitochondria in its yellow leaves. Map-based cloning revealed a missense mutation in OsIspE (LOC_Os01g58790) in gry340 mutant plants. OsIspE is constitutively expressed in all tissues, and its encoded protein is targeted to the chloroplast. Further, the mutant phenotype of gry340 was rescued by introduction of the wild-type gene. Therefore, we have successfully identified an IspE gene in monocotyledons via map-based cloning, and confirmed that the green-revertible yellow leaf phenotype of gry340 does result from a single nucleotide mutation in the IspE gene. In addition, the ispE ispF double mutant displayed an etiolation lethal phenotype, indicating that the isoprenoid precursors from the cytosol cannot efficiently compensate for the deficiency of the MEP pathway in rice chloroplasts. Furthermore, real-time quantitative reverse transcription-PCR suggested that this functional defect in OsIspE affected the expression of not only other MEP pathway genes but also that of MVA pathway genes, photosynthetic genes and mitochondrial genes.

[Polydatin induces human cervical cancer cell apoptosis via PI3K/AKT/mTOR signaling pathway].

To observe the effect of polydatin on proliferation and apoptosis of cervical cancer HeLa cells and explore its possible mechanism. The growth inhibitory effect was detected with MTT assay. After HeLa cells were treated with different concentrations (50, 100, 150 µmol•L⁻¹) of polydatin, MTT assay was used to detect the inhibitory effect of polydatin on proliferation of HeLa cells; Acridine orange/ethidium bromide staining was used for morphological changes in apoptotic HeLa cells； Annexin/propidium iodide staining was applied to detect HeLa cell apoptotic rate. In addition, flow cytometry was employed to analyze apoptosis and cell cycle distribution； RT-PCR and Western blot assay were used to detect PI3K, AKT, mTOR, and P70S6K mRNA and protein expression levels. The results showed that polydatin significantly inhibited HeLa cells proliferation in a dose-dependent manner. Polydatin can cause S phase arrest for HeLa cells, promote cell apoptosis and decrease the mRNA and protein expression levels of PI3K, AKT, mTOR and P70S6K. It indicated that polydatin could inhibit proliferation and induce apoptosis of cervical cancer HeLa cells, and the mechanism may be associated with inhibiting the PI3K/AKT/mTOR signaling pathway and suppressing downstream gene expression.

Lysine succinylation analysis reveals the effect of Sirt5 on synovial fibroblasts in rheumatoid arthritis patients.

Rheumatoid arthritis (RA) is an autoimmune disease with complex etiology, and its pathological mechanism remains unclear. Our aim was to explore the effect of protein succinylation on RA by silencing Sirt5, sequencing succinylated proteins, and analyzing the sequencing results to identify potential biomarkers. We wanted to gain a clearer understanding of RA pathogenesis, quantitative assessment of succinylated proteins in Fibroblast-like synoviocytes (FLS) from RA patients using liquid chromatography- tandem mass spectrometry and enrichment analysis investigated using Gene Ontology (GO) and Kyoto Encyclopedia of Genes and Genomes (KEGG). A total of 679 proteins and 2,471 lysine succinylation sites were found in RA patients, and 436 differentially expressed proteins and 1,548 differentially expressed succinylation sites were identified. Among them, 48 succinylation sites were upregulated in 38 proteins and 144 succinylation sites were downregulated in 82 proteins. Bioinformatics showed that succinylated proteins were significantly enriched in amino and fatty acid metabolisms. Results indicated that Sirt5 can affect various biological processes involved in RA FLSs, and succinylation caused by silencing Sirt5 plays a major role in RA progression. This study provides further understanding of RA pathogenesis and may facilitate searching for potential RA biomarkers.

Telotristat Etiprate alleviates rheumatoid arthritis by targeting LGALS3 and affecting MAPK signaling.

Rheumatoid arthritis (RA) is one of the most widespread chronic immune-mediated inflammatory diseases characterized by continuous erosion of bone and cartilage by synovial hyperplasia. Telotristat Etiprate is an inhibitor of tryptophan hydroxylase, a rate-limiting enzyme in the biosynthesis of serotonin. Telotristat Etiprate can be used in the treatment of carcinoid syndrome. The purpose of this study was to explore the effect of Telotristat Etiprate on RA and its mechanism. We investigated Telotristat Etiprate in collagen-induced arthritis (CIA) model mice and in rheumatoid arthritis synovial fibroblasts (RASFs). Results showed that Telotristat Etiprate had anti-inflammatory effects both in vitro and in vivo, can inhibit the invasion and migration of cells, inhibit the formation of pannus, and induce cell apoptosis. Transcriptome sequencing (RNA-seq) and mass spectrometry analysis showed that Galectins-3 (LGALS3) could be a newly identified target of Telotristat Etiprate, affecting the phosphorylation of the MAPK signaling pathway through UBE2L6, thereby improving RA.

Evaluation of 18F-FAPI-04 Imaging in Assessing the Therapeutic Response of Rheumatoid Arthritis.

PURPOSE: Fibroblast activating protein (FAP) is highly expressed in the synovial tissues of rheumatoid arthritis (RA) patients. The aim of this study was to determine the feasibility of PET imaging with an Al[18F] F-NOTA-labeled FAP inhibitor 04(18F-FAPI-04) for the evaluation of arthritic progression and therapeutic response in experimental arthritis. METHODS: Fibroblast-like synoviocytes (FLSs) were obtained from patients with RA or osteoarthritis (OA), and the relationship between 18F-FAPI-04 uptake and the inflammatory activity of RA FLSs was investigated. Collagen-induce arthritis (CIA) mice models were established and treated with methotrexate (MTX) or etanercept (ETC). Then, PET imaging was performed 24 h following 18F-FAPI-04 injection. The imaging results were compared by assessing macroscopic arthritis scores and histological staining. RESULTS: 18F-FAPI-04 uptake was obvious in RA FLSs that characterizing FAP activation. The higher the uptake of 18F-FAPI-04, the more severity of the inflammatory phenotype in RA FLS. Furthermore, the uptake of 18F-FAPI-04 in inflamed joints could be found even before the deformity of the parental joints could be observed by histological examination. Both MTX and ETC were effective in inhibiting the progression of arthritis in CIA mice was confirmed by macroscopic, histological, and radiographic pathology scores. Importantly, 18F-FAPI-04 uptake declined accordingly in CIA models following MTX and ETC treatment. CONCLUSIONS: These findings suggest that PET imaging of 18F-FAPI-04 can be used to monitor treatment response in RA, and is more sensitive in disease speculation than macroscopic arthritis scoring.

Vitamin D-binding protein (group-specific component) has decreased expression in rheumatoid arthritis.

OBJECTIVES: This study used a proteomic approach to screen the proteins with decreased expression in the synovial tissues of rheumatoid arthritis (RA) patients by comparing their expression profiles to that of osteoarthritis (OA) and ankylosing spondylitis (AS) patients. The result was complemented by a SNP analysis. METHODS: Proteins extracted from the synovial membranes (n=10 for each disease) were separated by 2-D electrophoresis. The proteins with significantly decreased expression in the RA samples were subjected to MALDI-TOF/TOF MS. The result was verified using western blotting. Tag SNPs located in the targeted gene were assessed using the Taqman assay in a cohort of 267 Chinese patients with RA, 51 patients with AS and 160 healthy controls. The genotyping result was confirmed in a large cohort of 389 patients with RA, 200 patients with AS and 371 healthy controls. RESULTS: The proteomic approach detected significantly decreased expression of vitamin D-binding protein (VDBP) in the synovial membranes from patients with RA, which was confirmed with western blot analysis. rs2282679 was significantly associated with RA and AS (p=0.026794 and 0.007566, respectively). The result was confirmed in a large cohort of RA (OR=0.678639, 95%CI=[0.541113~0.851118], p=0.000776) and AS (OR=0.564053, 95%CI=[0.433716~0.733558], p=1.79e-005). CONCLUSIONS: 1,25-dihydroxyvitamin D3 inhibits cell proliferation, immunoglobulin production and the release of cytokines through binding to VDBP. VDBP also mediates bone resorption by activating osteoclasts. The decreased expression and the genetic effect of VDBP in RA suggest a novel pathogenic pathway that vitamin D contributes to the arthritic process of the disease.

Renal Abscess Caused by Crizotinib: A Rare Case Report.

Crizotinib is a tyrosine kinase inhibitor that has been found to be effective in the treatment of c-ros oncogene 1-positive non-small cell lung cancer. Although this targeted agent for treating cancer has shown superiority to standard chemotherapy in some ways, this drug has adverse effects, such as the development of renal abscesses. Some associated renal damage may disappear with crizotinib withdrawal. Hence, we present the case of a 58-year-old man with non-small cell lung cancer on crizotinib therapy who developed bilateral renal abnormal space-occupying lesions, successively which were difficult to identify using various imaging methods; even PET-CT highly suspected the right renal masses as malignant. Finally, the right renal lesions were confirmed as renal abscesses by postoperative pathology. The left renal lesion was considered as renal cysts through the lesion disappearing after crizotinib withdrawal. There have been very few reports in this respect, especially proved by various methods and confirmed by postoperative pathology. It is important to recognize this drug-related complication in order to avoid incorrect diagnosis and inadequate therapy. It is necessary to monitor renal changes after taking crizotinib.

PET imaging to assess fibroblast activation protein inhibitor biodistribution: A training program adapted to pharmacology education.

In the process of pharmacology education, practical teaching is an important complement to theoretical teaching. These activities include the use of experimental animals to obtain certain pharmacological parameters or to help students understand certain classical concepts. However, the growing interest in laboratory animal welfare, the rapid development of pharmacology research and the challenges of cultivating innovative pharmacy talent create a need for innovative and flexible in vitro experiments for teaching purposes. Here, we report the application of positron emission tomography (PET) imaging of 18 F-labeled fibroblast activation protein inhibitor (18 F-FAPi) to practical pharmacology teaching, enabling dynamic visualization of the distribution and excretion process of FAPi in mice. Students can quantitatively analyze the distribution of FAPi in various tissues and organs without sacrificing the mice. Furthermore, the newly implemented method resulted in highly reproducible results and was generally appreciated by the students. Additionally, the application of PET imaging in pharmacokinetic teaching can not only greatly reduce the use of experimental animals but also need not sacrificing animals. Of note is that dynamic scanning data from this project can be used for online practical teaching during COVID-19 pandemic.

Euphorbia factor L3 ameliorates rheumatoid arthritis by suppressing the inflammatory response by targeting Rac family small GTPase 1.

Euphorbia factor L3 (EFL3) is extracted from Euphorbia lathyris and is known for its anti-inflammatory properties. This study focused on the potential anti-inflammatory and therapeutic effects of EFL3 on rheumatoid arthritis (RA) using fibroblast-like synoviocytes (FLSs) and arthritis animal models. Functional analysis showed that EFL3 could ameliorate the inflammatory phenotype of FLSs derived from RA patients, as evidenced by the decreases in cell viability, migration, invasion and cytokine production. Luciferase activity, Western blotting and immunofluorescence assays demonstrated that EFL3 inhibited the nuclear translocation of the p65 subunit and the subsequent activation of the nuclear factor kappa-Β (NF-κB) pathway. Furthermore, the therapeutic effects of EFL3 against arthritic progression were evidenced by decreases in joint swelling, arthritis scores, inflammatory factor production, synovial hyperplasia, and bone destruction in collagen-induced arthritis (CIA) and tumor necrosis factor-α (TNF-α) transgenic (TNF-tg) mouse models. Molecular analysis identified Rac family small GTPase 1 (Rac1) as the potential target that was required for EFL3-mediated suppression of the inflammatory RA FLS phenotype. In summary, this study uncovered the therapeutic potential of EFL3 in RA, which suggests its future clinical use.

Azithromycin alleviates the severity of rheumatoid arthritis by targeting the unfolded protein response component of glucose-regulated protein 78 (GRP78).

BACKGROUND AND PURPOSE: Azithromycin is a macrolide antibiotic with anti-inflammatory properties. We aim to substantiate the treatment potential of azithromycin in rheumatoid arthritis. EXPERIMENTAL APPROACH: Gene expression profiles were collected by RNA sequencing and the effects of azithromycin were assessed by in vitro and in vivo assays on the effects of azithromycin-mediated blockade of glucose-regulated protein 78 (GRP78). Anti-inflammatory activity of azithromycin was measured in fibroblast-like synoviocytes from rheumatoid arthritis patients and in collagen-induced arthritis in DBA/1 mice. Characterization of the binding of azithromycin to GRP78 was performed using drug affinity responsive target stability, proteomics and cellular thermal shift assays. Azithromycin-mediated inhibition of GRP78 and its relationship to its anti-arthritic activity was assessed. KEY RESULTS: Azithromycin reduced proinflammatory factor production, cell migration, invasion and chemoattraction and enhanced apoptosis, reducing the deleterious inflammatory response of rheumatoid arthritis fibroblast-like synoviocytes in vitro. Azithromycin ameliorated the severity of collagen-induced arthritis lesions as efficiently as the TNFα inhibitor etanercept. Transcriptional analyses suggested that azithromycin treatment impairs signalling cascades associated with cholesterol and lipid biosynthesis. GRP78 was identified as a novel target of azithromycin. Azithromycin-mediated activation of the unfolded protein response via the inhibition of GRP78 activity is required not only for inducing the expression of C/EBP-homologous protein (ChOP) but also for the activating sterol-regulatory element binding protein (SREBP) and its targeted genes involved in cholesterol and lipid biosynthetic processes. Furthermore, deletion of GRP78 abolished the anti-arthritic activity of azithromycin. CONCLUSION AND IMPLICATIONS: These findings indicate that azithromycin can used to treat rheumatoid arthritis.

ATF6α contributes to rheumatoid arthritis by inducing inflammatory cytokine production and apoptosis resistance.

Objective: The contribution of activating transcription factor 6α (ATF6α) in rheumatoid arthritis (RA) pathogenesis, especially on fibroblast-like synoviocytes (FLSs), has been suggested by its sensitivity to inflammatory stimulus. However, the exact role and therapeutic potential of ATF6α in RA remains to be fully elucidated. Methods: ATF6α expression was determined in joint tissues and FLS, and gain-of-function and loss-of-function analyses were applied to evaluate the biological roles of ATF6α in RA FLSs. A murine collagen-induced arthritis (CIA) model, combining both gene deletion of ATF6α and treatment with the ATF6α inhibitor Ceapin-A7, was employed. Joint inflammation, tissue destruction, circulating levels of inflammatory cytokines were assessed in CIA mice. Transcriptome sequencing analysis (RNASeq), molecular biology, and biochemical approaches were performed to identify target genes of ATF6α. Results: ATF6α expression was significantly increased in synovium of RA patients and in synovium of mice subjected to CIA. ATF6α silencing or inhibition repressed RA FLSs viability and cytokine production but induced the apoptosis. CIA-model mice with ATF6α deficiency displayed decreased arthritic progression, leading to profound reductions in clinical and proinflammatory markers in the joints. Pharmacological treatment of mice with Ceapin-A7 reduced arthritis severity in CIA models. RNA-sequencing of wild-type and knockdown of ATF6α in RA FLSs revealed a transcriptional program that promotes inflammation and suppresses apoptosis, and subsequent experiments identified Baculoviral IAP Repeat Containing 3 (BIRC3) as the direct target for ATF6α. Conclusion: This study highlights the pathogenic role of ATF6α-BIRC3 axis in RA and identifies a novel pathway for new therapies against RA.

Immunopathogenic mechanisms of rheumatoid arthritis and the use of anti-inflammatory drugs.

Rheumatoid arthritis (RA) is a chronic, progressive autoimmune disease characterized by synovitis and symmetrical joint destruction. RA has become one of the key diseases endangering human health, but its etiology is not clear. Therefore, identifying the immunopathogenic mechanisms of RA and developing therapeutic drugs to treat autoimmune diseases have always been difficult. This article mainly reviews the immunopathogenic mechanism of RA and advances in the study of anti-inflammatory drugs in order to provide a reference for the treatment of RA and drug development in the future.

ChIP-sequencing analysis of E2F transcription factor 2 reveals its role in various biological processes of rheumatoid arthritis synovial fibroblasts.

The development and progression of rheumatoid arthritis (RA) are complex and the pathogenesis of this disease is not fully understood. E2F transcription factor 2 (E2F2) affects the development and progression of many diseases. To identify the mechanisms underlying the role of E2F2 in RA, chromatin immunoprecipitation was performed followed by sequencing (ChIP-seq) using the E2F2 antibody. Gene Ontology (GO) analysis of differentially expressed genes (DEGs) and Kyoto Encyclopedia of Genes and Genomes (KEGG) pathway enrichment of captured downstream target genes and Metascape analysis of 22 protein molecules partly elucidated the mechanism by which E2F2 affects the progression of RA. Results indicated that E2F2 affects the metabolism of RASFs and the development of ribosome synthesis as well as the stress response. Results indicated that E2F2 can affect multiple biological processes involving RASFs and indicate a unique possibility of targeting E2F2 in the treatment of RA.

The E2F transcription factor 2: What do we know?

E2F transcription factor 2 (E2F2) is a member of the E2F family of transcription factors. The classical view is that some E2Fs act as "activators" and others "inhibitors" of cell cycle gene expression. However, the so-called "activator" E2F2 is particularly enigmatic, with seemingly contradictory roles in the cell cycle, proliferation, apoptosis, inflammation, and cell migration and invasion. How can we rationalize the apparently opposing functions of E2F2 in different situations? This is difficult because different methods of studying E2F2 have yielded conflicting results, so extrapolating mechanisms from an observed endpoint is challenging. This review will attempt to summarize and clarify these issues. This review focuses on genetic studies that have helped elucidate the biological functions of E2F2 and that have enhanced our understanding of how E2F2 is integrated into pathways controlling the cell cycle, proliferation, apoptosis, inflammation, and cell migration and invasion. This review will also discuss the function of E2F2 in cancer and other diseases. This review provides a strong basis for further research on the biological function and clinical potential of E2F2.