Up-regulated DERL3 in fibroblast-like synoviocytes exacerbates inflammation of rheumatoid arthritis

Derlin-3 manipulates the endoplasmic reticulum stress and IgG4 secretion of plasma cells in lung adenocarcinoma

Derlin-3 has been implicated as an essential element in the degradation of misfolded lumenal glycoproteins induced by endoplasmic reticulum (ER) stress. However, its potential biomechanisms in the tumor microenvironment (TME) of lung adenocarcinoma (LUAD) remains to be elucidated. In the present study, we found that Derlin-3 was predominantly elevated in LUAD tissues, and could predict worse prognosis of LUAD patients. ScRNA-seq analysis indicated that Derlin-3 was mainly enriched in B lymphocytes in the TME, especially in plasma cells. Moreover, Derlin-3 may be involved in ER stress and IgG4 secretion in plasma cells by targeting Hrd1/p38/PRDM1 pathway. While the aberrant IgG4 production may be an essential driver of the polarization of macrophages towards the M2 phenotype. Additionally, downregulation of Derlin-3 could inhibit plasma cells infiltration and M2 macrophage polarization in vivo. Our results indicated that Derlin-3 could shape TME via ER stress to harness immune function, which might serve as a promising immunotherapeutic target in LUAD.

KAT3B-mediated succinylation of DERL3 suppresses osteogenic differentiation by promoting M1/M2 macrophage polarization

Periodontitis is a chronic inflammatory disease influenced by macrophage polarization. Additionally, succinylation-enriched Porphyromonas gingivalis is a pathogenic factor of periodontitis. However, the role of succinylation in the pathogenesis of periodontitis remains unclear. This study aimed to investigate the effects of a succinyltransferase KAT3B on macrophage polarization, osteogenic differentiation, and the molecular mechanism. Macrophages RAW264.7 were cocultured with MC3T3-E1-differentiated osteoblasts, and macrophage polarization and osteogenic differentiation were evaluated. iTRAQ-based proteomic analysis identified that DERL3 was highly expressed in lipopolysaccharide (LPS)-treated MC3T3-E1 cells. The TLR4/MyD88 pathway is closely related to inflammatory response. Thus, the succinylation of DERL3 and the TLR4/MyD88 pathway were assessed using immunoblotting. The results showed that KAT3B-mediated succinylation was increased in LPS-treated MC3T3-E1 cells and patients with periodontitis. Knockdown of KAT3B inhibited macrophage M1-like polarization and promoted M2-like polarization, thereby promoting osteogenic differentiation in LPS-treated osteoblasts. Mechanically, overexpression of KAT3B promoted the succinylation of DERL3 and stabilized this protein, thereby upregulating DERL3 expression. Rescue experiments showed that DERL3 reversed the promotion of osteogenic differentiation and M2/M1 macrophage polarization caused by KAT3B knockdown. Moreover, DERL3 activated the TLR4/MyD88 pathway, and inhibition of this pathway reversed macrophage polarization and osteogenesis mediated by DERL3. In vivo experiments showed that KAT3B knockdown attenuated experimental periodontitis in rats. In conclusion, silencing of KAT3B promotes osteogenic differentiation by inducing M2/M1 macrophage polarization through the succinylation DERL3, which regulates the TLR4/MyD88 pathway, thereby attenuating periodontitis. These findings suggest that KAT3B may be a promising therapeutic target for periodontitis.

Integrated profiling of endoplasmic reticulum stress-related DERL3 in the prognostic and immune features of lung adenocarcinoma

Background

DERL3 has been implicated as an essential element in the degradation of misfolded lumenal glycoproteins induced by endoplasmic reticulum (ER) stress. However, the correlation of DERL3 expression with the malignant phenotype of lung adenocarcinoma (LUAD) cells is unclear and remains to be elucidated. Herein, we investigated the interaction between the DERL3 and LUAD pathological process.

Methods

The Cancer Genome Atlas (TCGA) database was utilized to determine the genetic alteration of DERL3 in stage I LUAD. Clinical LUAD samples including carcinoma and adjacent tissues were obtained and were further extracted to detect DERL3 mRNA expression via RT-qPCR. Immunohistochemistry was performed to evaluate the protein expression of DERL3 in LUAD tissues. The GEPIA and TIMER website were used to evaluate the correlation between DERL3 and immune cell infiltration. We further used the t-SNE map to visualize the distribution of DERL3 in various clusters at the single-cell level via TISCH database. The potential mechanisms of the biological process mediated by DERL3 in LUAD were conducted via KEGG and GSEA.

Results

It was indicated that DERL3 was predominantly elevated in carcinoma compared with adjacent tissues in multiple kinds of tumors from the TCGA database, especially in LUAD. Immunohistochemistry validated that DERL3 was also upregulated in LUAD tissues compared with adjacent tissues from individuals. DERL3 was preliminarily found to be associated with immune infiltration via the TIMER database. Further, the t-SNE map revealed that DERL3 was predominantly enriched in plasma cells of the B cell population. It was demonstrated that DERL3 high-expressed patients presented significantly worse response to chemotherapy and immunotherapy. GSEA and KEGG results indicated that DERL3 was positively correlated with B cell activation and unfolded protein response (UPR).

Conclusion

Our findings indicated that DERL3 might play an essential role in the endoplasmic reticulum-associated degradation (ERAD) process in LUAD. Moreover, DERL3 may act as a promising immune biomarker, which could predict the efficacy of immunotherapy in LUAD.

Daphnes Cortex and its licorice-processed products suppress inflammation via the TLR4/NF-κB/NLRP3 signaling pathway and regulation of the metabolic profile in the treatment of rheumatoid arthritis

ETHNOPHARMACOLOGICAL RELEVANCE

Daphnes Cortex (Daphne Giraldii Nitsche, DGN) is a popular traditional Chinese herbal medicine for traumatic injuries and rheumatoid arthritis (RA) in the Shaanxi and Gansu provinces of China. Due to skin irritation caused by raw DGN (RDGN), licorice-processed DGN products are usually used in clinical practice. However, the efficacy and mechanisms of action between DGN and its licorice-processed DGN products in treating RA have not been compared.

AIMS

This study compared the efficacy and elucidated the mechanisms in vitro and in vivo between RDGN and its licorice-processed DGN products in treating RA.

MATERIALS AND METHODS

A collagen-induced RA rat model was established, and treated with different doses of RDGN and its licorice-processed DGN products for 4 weeks to explore the therapeutic effects. The anti-inflammatory effects were assessed in RAW 264.7 macrophages stimulated by lipopolysaccharide (LPS). Analyses of the differential quality markers (DQMs) between DGN and its licorice-processed DGN products using ultra-high performance liquid chromatography-quadrupole time-of-flight mass spectrometry, and non-targeted metabolomics analyses of rat synovial tissues were used to systematically explore correlations between DGN processing and its efficacy.

RESULTS

Licorice-processed DGN products significantly ameliorated RA symptoms in CIA rats. Licorice-processed DGN products also regulated inflammatory cytokines, matrix metalloproteinases, and vascular endothelial growth factor in the serum and cell supernatants. Licorice-processed DGN products significantly inhibited Toll-like receptor 4/nuclear factor kappa B/NOD-like receptor family, pyrin domain containing 3 (TLR4/NF-κB/NLRP3) signaling in CIA rats and LPS-induced RAW264.7 cells. The DQMs between RDGN and its licorice-processed DGN products were identified, most of which were amino acids or energy-related metabolites present in licorice-processed DGN products. Correlations between DQMs with differential metabolites and differential metabolic pathways were established.

CONCLUSIONS

Licorice-processed DGN products displayed better anti-inflammatory effects via the TLR4/NF-κB/NLRP3 signaling pathway on CIA rats and LPS-induced RAW264.7 cells, and regulation of the metabolic profile in treating RA.

New potential therapeutic approaches targeting synovial fibroblasts in rheumatoid arthritis

Synovial cells play a key role in joint destruction during chronic inflammation. In particular, activated synovial fibroblasts (SFs) undergo intrinsic alterations leading to an aggressive phenotype mediating cartilage destruction and bone erosion in rheumatoid arthritis (RA). Recent research has revealed a number of targets to control arthritogenic changes in SFs. Therefore, identification of SF phenotypes, control of epigenetic changes, modulation of cellular functions, or regulation of the activity of cation channels and different signaling pathways has been investigated. Although many of these approaches have shown efficacy in vitro and in animal models of RA, further research is needed to select the most relevant targets for drug development. This review is focused on the role of SFs as a potential strategy to discover novel therapeutic targets in RA aimed at preserving joint architecture and function.

Azithromycin alleviates the severity of rheumatoid arthritis by targeting the UPR component GRP78

BACKGROUND AND PURPOSE

Azithromycin (AZM) is a macrolide antibiotic with well-described anti-inflammatory properties. This study aimed to substantiate the treatment potential of AZM in rheumatoid arthritis (RA).

EXPERIMENTAL APPROACH

Gene expression profiles were collected by RNA sequencing, and the effects of AZM were assessed in functional assays. In vitro and in vivo assays were performed to examine the effects of AZM-mediated blockade of glucose-regulated protein 78 (GRP78). Assays to define the anti-inflammatory activity of AZM using fibroblast-like synoviocytes (FLSs) from RA patients and collagen-induced arthritis (CIA) in DBA/1 mice were performed. Identification and characterization of the binding of AZM to GRP78 was performed using drug affinity responsive target stability assays, proteomics and cellular thermal shift assays. AZM-mediated inhibition of GRP78 and the dependence of the antiarthritic activity of AZM on GRP78 were assessed.

KEY RESULTS

AZM reduced proinflammatory factor production, cell migration, invasion and chemoattraction and enhanced apoptosis, thereby reducing the deleterious inflammatory response of RA FLSs in vitro. AZM ameliorated the severity of CIA lesions as efficiently as the anti-tumour necrosis factor (anti-TNF) biological agent etanercept (ETC). Transcriptional analyses suggested that AZM treatment impairs signalling cascades associated with cholesterol and lipid biosynthetic processes. GRP78 was identified as a novel target of AZM. AZM-mediated activation of the unfolded protein response (UPR) 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 antiarthritic activity of AZM.

CONCLUSION AND IMPLICATIONS

These findings confirmed that AZM is a therapeutic drug for RA treatment.

Quantitative Proteomic Analysis of Synovial Tissue Reveals That Upregulated OLFM4 Aggravates Inflammation in Rheumatoid Arthritis

Tandem mass tag (TMT)-coupled liquid chromatography coupled with tandem mass spectrometry is a powerful method to investigate synovial tissue protein profiles in patients with rheumatoid arthritis (RA) and osteoarthritis (OA). Protein was isolated from synovial tissue samples of 22 patients and labeled with a TMT kit. Over 500 proteins were identified as the differential expression protein on comparing RA and OA synovial tissue, including 239 upregulated and 271 downregulated proteins. Data are available via ProteomeXchange with identifier PXD027703. Gene ontology and Kyoto Encyclopedia of Genes and Genomes analysis showed that the majority participated in the developmental processes and protein processing in the endoplasmic reticulum. Olfactomedin 4 (OLFM4), a secreted glycoprotein, in joint inflammation of RA was explored. OLFM4 was upregulated in RA synovial tissue samples. In fibroblast-like synoviocytes (FLS), inflammation cytokines, TNF-α, interleukin (IL)-1β, and LPS can upregulate OLFM4. After OLFM4 knockdown under TNF-α stimulation, RA FLS proliferation was inhibited and the expression of CXCL9, CXCL11, and MMP-1 was decreased. Overall, the RA synovial tissue protein expression profile by proteomic analysis shows some unique targets in RA pathophysiology, and OLFM4 in FLS plays an important role in RA joint inflammation. OLFM4 can be a promising therapeutic target in RA synovial tissue.