Transcription factor EB promotes rheumatoid arthritis of Sprague-Dawley rats via regulating autophagy

Multi-omics study on autophagic dysfunction molecular network in the pathogenesis of rheumatoid arthritis

BACKGROUND

Autophagy is associated with the development of rheumatoid arthritis (RA), but its genetic pathological mechanisms remain incompletely understood. In this study, we employed summary-data-based Mendelian randomization (SMR) and co-localization analysis to systematically investigate the relationship between autophagy-related genes and RA.

METHODS

We obtained summary data on blood methylation (mQTL), gene expression (eQTL), and protein abundance (pQTL) from respective quantitative trait locus (QTL) studies. Genetic association data for RA were primarily derived from the FinnGen database, with validation performed using the UK Biobank (UKB) and GWAS Catalog databases. SMR analysis was conducted to evaluate the association between molecular characteristics of autophagy-related genes and RA. Subsequently, co-localization analysis was performed to determine whether the identified signals share the same causal genetic variants.

RESULTS

After integrating mQTL-eQTL multi-omics data, we identified two key autophagy genes, BCL2L1 and RAF1, which may have a causal relationship with RA. Significant associations were found for BCL2L1 (cg12873919, cg13989999) and RAF1 (cg26432171) in the SMR analysis of autophagy-related mQTL, eQTL, and GWAS data (p SMR < 0.05). In the integrated mQTL-eQTL SMR analysis, cg12873919 (p SMR = 1.40E-07, OR = 0.82, 95% CI [0.76-0.88]), cg13989999 (p SMR = 1.43E-06, OR = 0.78, 95% CI [0.71-0.87]), and cg26432171 (p SMR = 9.18E-09, OR = 1.83, 95% CI [1.49-2.25]) were all significantly validated. Methylation of cg12873919 and cg13989999 in BCL2L1 was associated with increased BCL2L1 expression, consistent with their negative impact on RA risk. Conversely, the cg26432171 site in RAF1 showed a positive correlation between gene methylation and expression. In the eQTL-GWAS SMR analysis, MAPK3 expression (p SMR = 7.24E-05, OR = 0.91, 95% CI [0.87-0.95]) was negatively correlated with RA risk, a finding supported by co-localization analysis (PPH4 > 0.5), suggesting that this gene may inhibit RA pathogenesis by regulating the autophagy process. Furthermore, protein level analysis also supported the protective role of MAPK3 (p SMR = 7.53E-05, OR = 0.89, 95% CI [0.84-0.94]).

CONCLUSION

We identified that autophagy-related genes BCL2L1 and RAF1 may be associated with RA risk, providing strong evidence from multi-omics data. This study identifies autophagy genes related to RA, potentially offering new insights into the pathogenesis of RA.

Selective autophagy in cancer: mechanisms, therapeutic implications, and future perspectives

Eukaryotic cells engage in autophagy, an internal process of self-degradation through lysosomes. Autophagy can be classified as selective or non-selective depending on the way it chooses to degrade substrates. During the process of selective autophagy, damaged and/or redundant organelles like mitochondria, peroxisomes, ribosomes, endoplasmic reticulum (ER), lysosomes, nuclei, proteasomes, and lipid droplets are selectively recycled. Specific cargo is delivered to autophagosomes by specific receptors, isolated and engulfed. Selective autophagy dysfunction is closely linked with cancers, neurodegenerative diseases, metabolic disorders, heart failure, etc. Through reviewing latest research, this review summarized molecular markers and important signaling pathways for selective autophagy, and its significant role in cancers. Moreover, we conducted a comprehensive analysis of small-molecule compounds targeting selective autophagy for their potential application in anti-tumor therapy, elucidating the underlying mechanisms involved. This review aims to supply important scientific references and development directions for the biological mechanisms and drug discovery of anti-tumor targeting selective autophagy in the future.

Anti-rheumatoid arthritis effects of total saponins from Rhizoma Panacis Majoris on adjuvant-induced arthritis in rats and rheumatoid arthritis fibroblast-like synoviocytes

BACKGROUND

Total saponins from Rhizoma Panacis Majoris (RPMTG) showed significant antitumour activity in our previous studies. Rheumatoid arthritis fibroblast-like synoviocytes (RA-FLS) with tumour-like characteristics have received attention as a therapeutic target for RA. However, the potential effect and mechanism of action of RPMTG against RA-FLS remain unclear.

OBJECTIVE

The study investigated the therapeutic effect of RPMTG on adjuvant-induced arthritis (AIA) in rats, and the regulation effect and underlying mechanism on apoptosis, autophagy of RA-FLS.

METHODS

The therapeutic effect of RPMTG was determined by the symptoms and signs of AIA rats. The production of inflammatory cytokines was detected by ELISA. Histopathological change of the ankle and synovial tissues were detected by HE staining. Flow cytometry, Hoechst 33342/PI staining, MDC staining, and TEM were used to determine the effects of RPMTG on apoptosis and autophagy. Western blotting was applied to detect the expression levels of proteins.

RESULTS

In AIA rats, RPMTG treatment ameliorated paw swelling, and arthritis score, restored synovial histopathological changes, inhibited the expression of IL-6 and IL-1β, exhibiting its potent anti-arthritis effect. In vitro, RPMTG depressed the proliferation of RA-FLS, arrested cell cycle in G0/G1 phase, and induced mitochondria-mediated apoptosis. Moreover, RPMTG significantly inhibited the autophagy in vivo and in vitro, proved by decreasing the expression of autophagy-related indicators (LC3II/LC3I, Beclin-1). Mechanistically, the study demonstrated that the activation of p38 MAPK and PI3K/Akt/mTOR pathways was mainly involved in the therapeutic effects of RPMTG. Interestingly, the effect of RPMTG on apoptosis was reversed after Rapamycin treatment, which preliminarily demonstrated that the inhibitory effect of RPMTG on autophagy was beneficial to the effect on inducing apoptosis. The regulation effect of RPMTG concurrently on apoptosis and autophagy revealed its unique advantages in RA treatment.

CONCLUSION

RPMTG showed potent therapeutic effects on AIA rats and induced apoptosis, inhibited autophagy mainly through activating the p38 MAPK and PI3K/Akt/mTOR pathways in RA-FLS.

Autophagy and the Lysosomal System in Cancer

Autophagy and the lysosomal system, together referred to as the autophagolysosomal system, is a cellular quality control network which maintains cellular health and homeostasis by removing cellular waste including protein aggregates, damaged organelles, and invading pathogens. As such, the autophagolysosomal system has roles in a variety of pathophysiological disorders, including cancer, neurological disorders, immune- and inflammation-related diseases, and metabolic alterations, among others. The autophagolysosomal system is controlled by TFEB, a master transcriptional regulator driving the expression of multiple genes, including autophagoly sosomal components. Importantly, Reactive Oxygen Species (ROS) production and control are key aspects of the physiopathological roles of the autophagolysosomal system, and may hold a key for synergistic therapeutic interventions. In this study, we reviewed our current knowledge on the biology and physiopathology of the autophagolysosomal system, and its potential for therapeutic intervention in cancer.

A Review of APOE Genotype-Dependent Autophagic Flux Regulation in Alzheimer's Disease

Autophagy is a basic physiological process maintaining cell renewal, the degradation of dysfunctional organelles, and the clearance of abnormal proteins and has recently been identified as a main mechanism underlying the onset and progression of Alzheimer's disease (AD). The APOE ɛ4 genotype is the strongest genetic determinant of AD pathogenesis and initiates autophagic flux at different times. This review synthesizes the current knowledge about the potential pathogenic effects of ApoE4 on autophagy and describes its associations with the biological hallmarks of autophagy and AD from a novel perspective. Via a remarkable variety of widely accepted signaling pathway markers, such as mTOR, TFEB, SIRT1, LC3, p62, LAMP1, LAMP2, CTSD, Rabs, and V-ATPase, ApoE isoforms differentially modulate autophagy initiation; membrane expansion, recruitment, and enclosure; autophagosome and lysosome fusion; and lysosomal degradation. Although the precise pathogenic mechanism varies for different genes and proteins, the dysregulation of autophagic flux is a key mechanism on which multiple pathogenic processes converge.