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.

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.

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.

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.

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.

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.

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.

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.

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.

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.

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.

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.

IL13Rα1 prevents a castration resistant phenotype of prostate cancer by targeting hexokinase 2 for ubiquitin-mediated degradation.

OBJECTIVE: Androgen deprivation therapy (ADT) is still the principal treatment option for prostate cancer (PCa). In addition to reactivation of androgen receptor signaling, the resistance of PCa to apoptosis during ADT also contributes to castration resistant PCa (CRPC). A previous study reported that gene transfer of IL-13Rα2 into PCa cells sensitized the cells to the IL-13R-targeted cytotoxin IL13Rα1, leading to apoptosis. Compared with IL-13Rα2, IL13Rα1 is more constitutively expressed in PCa cells, but its function in PCa remains to be established. METHODS: We determined the role and expression of IL13Rα1 in PCa cancer cells using western blotting, flow cytometry, and cell proliferation assays. Co-immunoprecipitation and mass spectrometry were used to identify the proteins that interacted with IL13Rα1, to elucidate its function. RESULTS: In this study, we showed that IL13Rα1 was selectively suppressed in androgen-deprived PCa cells and that its suppression tended to be associated with poor prognoses of PCa patients. IL13Rα1 overexpression promoted apoptosis and inhibited tumor growth under androgen-deprived or castrated conditions (P < 0.01). Mechanistically, IL13Rα1 recruited and facilitated ubiquitin protein ligase E3C-mediated ubiquitination and degradation of hexokinase 2 (HK2), resulting in glycolytic inhibition and eventually leading to PCa cell apoptosis. Furthermore, our data revealed that mutated ataxia-telangiectasia kinase phosphorylated and facilitated the selective ubiquitin proteasome-mediated degradation of HK2. Notably, IL13Rα1-overexpressing PCa cells were more susceptible to apoptosis and exhibited reduced tumor growth after exposure to the HK2 inhibitor, 2-deoxy-D-glucose (P < 0.01). CONCLUSIONS: Our data identified a tumor suppressor role for IL13Rα1 in preventing the resistance of PCa cells to apoptosis during androgen deprivation by inhibiting glycolysis. IL13Rα1-mediated signaling involving HK2 may therefore provide a novel treatment target and strategy for CRPC.

Isopsoralen ameliorates rheumatoid arthritis by targeting MIF.

BACKGROUND: Isopsoralen (IPRN), one of the active ingredients of Psoralea corylifolia Linn, has anti-inflammatory properties. We attempted to investigate the inhibitory effects of IPRN on rheumatoid arthritis (RA) and characterize its potential mechanism. METHODS: RA fibroblast-like synoviocytes (FLSs) and mice with collagen-induced arthritis (CIA) were used as in vitro and in vivo models to analyze the antiarthritic effect of IPRN. Histological analysis of the inflamed joints from mice with CIA was performed using microcomputed tomography (micro-CT) and hematoxylin-eosin (HE) staining. RNA sequencing (RNA-Seq), network pharmacology analysis, molecular docking, drug affinity responsive target stability (DARTS) assay, and cellular thermal shift assay (CETSA) were performed to evaluate the targets of IPRN. RESULTS: IPRN ameliorated the inflammatory phenotype of RA FLSs by inhibiting their cytokine production, migration, invasion, and proangiogenic ability. IPRN also significantly reduced the severity of CIA in mice by decreasing paw thickness, arthritis score, bone damage, and serum inflammatory cytokine levels. A mechanistic study demonstrated that macrophage migration inhibitory factor (MIF), a key protein in the inflammatory process, was the specific target by which IPRN exerted its anti-inflammatory effects in RA FLSs. CONCLUSION: Our study demonstrates the antiarthritic effect of IPRN, which suggests the therapeutic potential of IPRN in 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.

Microbial community in Chinese traditional fermented acid rice soup (rice-acid) and its correlations with key organic acids and volatile compounds.

Rice-acid is a unique Chinese traditional fermented acid rice soup and its microbial community plays an important role in the formation of flavour compounds. In the study, rice-acid products from high-temperature and low-temperature fermentation methods were selected to analyze the microbial community, organic acids, and volatile flavour compounds (VFCs). The main bacterial and fungal phyla in Chinese traditional fermented rice-acid were determined to be Firmicutes and Ascomycota, including 62 bacterial genera and 57 fungal genera. The dominant bacterial genera were Lactobacillus, Acetobacter, and Prevotella and the dominant fungal genera were Naumovia, Pichia, Candida, and Saccharomyces. Among organic acids in rice-acid, L-lactic acid had the highest concentration, followed by malic acid, acetic acid, citric acid, oxalic acid, and tartaric acid. Volatile flavour compounds had a high contribution to the flavour, including ethyl acetate, ethanol, acetic acid, propanoic acid, 1-octen-3-ol, 2-nonanol, 2-undecanol, propyl propionate, ethyl propanoate, propyl propionate, and 2,3-butanedione. The microorganisms which were closely correlated with key organic acids in rice-acid included Lactobacillus, Acetobacter, Pichia, Candida, Kluyveromyces and Meyerozyma. The microorganisms which were correlated with VFCs included Acetobacter, Prevotella, Kluyveromyces and Saccharomyces. In particular, Lactobacillus, Pichia, Malassezia, Clavispora, Rhizopus and Cystofilobasidium were significantly positively correlated with lactic acid in rice-acid. Kluyveromyces, Saccharomyces and Emericella were significantly positively correlated with ethanol and ethyl acetate. The study provides the basis for improving the quality of rice-acid.

IL13Rα1 protects against rheumatoid arthritis by combating the apoptotic resistance of fibroblast-like synoviocytes.

BACKGROUND: Endoplasmic reticulum (ER) stress is closely related with the pathological progression of rheumatoid arthritis (RA), and fibroblast-like synoviocytes (FLSs) are known as its resistance against ER stress-induced apoptosis. Studies on overcoming such resistance would provide a novel treatment strategy for RA in a clinical setting. METHODS: IL13Rα1 expression was assessed in the synovial tissue by RT-qPCR, immunohistology, and Western blot. Gain or loss of functional analysis was applied to evaluate the biological roles of IL13Rα1 in RA FLSs. Cell viability and apoptosis were assessed by MTS, Western blot, and flow cytometry. The therapeutic effects of IL13Rα1 on the severity of type II collagen-induced arthritis (CIA) in DBA-/1 mouse model were evaluated by scoring synovitis, hyperplasia, cartilage degradation, and bone destruction. RESULTS: IL13Rα1 expression was selectively downregulated when RA FLSs were stimulated by ER stress inducers. Functionally, IL13Rα1 overexpression could inhibit the viability, but induce the apoptosis of RA FLSs in the presence of ER stress inducers. Mechanistically, IL13Rα1 promotes cell apoptosis via transcriptionally activating trail expression. Besides, IL13Rα1 could interact and stabilize DR5 protein, thus forming a positive loop involving trail and DR5 to render RA FLSs more susceptible to apoptosis. Additionally, intraarticular injection of IL13Rα1 conferred therapeutic effects in CIA models and showed a limited degree of synovial proliferation and joint destruction. CONCLUSIONS: Together, our data establishes a regulatory role for IL13Rα1 to combat the apoptotic resistance of RA FLSs against ER stress. The inhibitory effects of IL13Rα1 on arthritis progression suggest the therapeutic potential in RA.

TXNDC5 protects synovial fibroblasts of rheumatoid arthritis from the detrimental effects of endoplasmic reticulum stress.

TXNDC5 is an endoplasmic reticulum (ER)-resident chaperone that protects the endothelium from secondary effects of ER stress. Previous studies by the current authors identified TXNDC5 as a key pathological factor in promoting the inflammatory phenotype of fibroblast-like synoviocytes (FLSs) from rheumatoid arthritis (RA). However, its activity in RA FLSs under ER stress remains unclear. The current study found that TXNDC5 is responsive to ER stress in RA FLSs since its expression was induced by ER stress at both the endogenous and secretory level. A functional study indicated that silencing TXNDC5 reduced the viability of RA FLSs more markedly in the presence of ER stressors. In contrast, rhTXNDC5 attenuated a decrease in cell viability as a result of ER stress. Moreover, silencing TXNDC5 attenuated the induction of IL-6 and IL-8 from RA FLSs in response to ER stress. In addition, rhTXNDC5 induced a greater increase in VEGF production during ER stress. These findings confirm the pro-survival and pro-inflammation roles of TXNDC5 under ER stress in RA FLSs. TXNDC5 appears to act as a mediator linking ER stress and inflammation of RA.