Hypoxia-induced the upregulation of stromal cell-derived factor 1 in fibroblast-like synoviocytes contributes to migration of monocytes into synovium tissue in rheumatoid arthritis

Multiomic analysis of monocyte-derived alveolar macrophages in idiopathic pulmonary fibrosis

BACKGROUND

Monocyte-derived alveolar macrophages (Mo_AMs) are increasingly recognised as potential pathogenic factors for idiopathic pulmonary fibrosis (IPF). While scRNAseq analysis has proven valuable in the transcriptome profiling of Mo_AMs, the integration analysis of multi-omics may provide additional dimensions of understanding of these cellular populations.

METHODS

We performed multi-omics analysis on 116 scRNAseq, 119 bulkseq and five scATACseq lung tissue samples from IPF. We built a large-scale IPF scRNAseq atlas and conducted the Monocle 2/3 as well as the Cellchat to explore the developmental path and intercellular communication on Mo_AMs. We also reported the difference in metabolisms, tissue repair and phagocytosis between Mo_AMs and tissue-resident alveolar macrophages (TRMs). To determine whether Mo_AMs affected pulmonary function, we projected clinical phenotypes (FVC%pred) from the bulkseq dataset onto the scRNAseq atlas. Finally, we used scATATCseq to uncover the upstream regulatory mechanisms and determine key drivers in Mo_AMs.

RESULTS

We identified three Mo_AMs clusters and the trajectory analysis further validated the origin of these clusters. Moreover, via the Cellchat analysis, the CXCL12/CXCR4 axis was found to be involved in the molecular basis of reciprocal interactions between Mo_AMs and fibroblasts through the activation of the ERK pathway in Mo_AMs. SPP1_RecMacs (RecMacs, recruited macrophages) were higher in the low-FVC group than in the high-FVC group. Specifically, compared with TRMs, the functions of lipid and energetic metabolism as well as tissue repair were higher in Mo_AMs than TRMs. But, TRMs may have higher level of phagocytosis than TRMs. SPIB (PU.1), JUNB, JUND, BACH2, FOSL2, and SMARCC1 showed stronger association with open chromatin of Mo_AMs than TRMs. Significant upregulated expression and deep chromatin accessibility of APOE were observed in both SPP1_RecMacs and TRMs.

CONCLUSION

Through trajectory analysis, it was confirmed that SPP1_RecMacs derived from Monocytes. Besides, Mo_AMs may influence FVC% pred and aggravate pulmonary fibrosis through the communication with fibroblasts. Furthermore, distinctive transcriptional regulators between Mo_AMs and TRMs implied that they may depend on different upstream regulatory mechanisms. Overall, this work provides a global overview of how Mo_AMs govern IPF and also helps determine better approaches and intervention therapies.

CXCR4/CXCL12 axis: "old" pathway as "novel" target for anti-inflammatory drug discovery

Inflammation is the body's defense response to exogenous or endogenous stimuli, involving complex regulatory mechanisms. Discovering anti-inflammatory drugs with both effectiveness and long-term use safety is still the direction of researchers' efforts. The inflammatory pathway was initially identified to be involved in tumor metastasis and HIV infection. However, research in recent years has proved that the CXC chemokine receptor type 4 (CXCR4)/CXC motif chemokine ligand 12 (CXCL12) axis plays a critical role in the upstream of the inflammatory pathway due to its chemotaxis to inflammatory cells. Blocking the chemotaxis of inflammatory cells by CXCL12 at the inflammatory site may block and alleviate the inflammatory response. Therefore, developing CXCR4 antagonists has become a novel strategy for anti-inflammatory therapy. This review aimed to systematically summarize and analyze the mechanisms of action of the CXCR4/CXCL12 axis in more than 20 inflammatory diseases, highlighting its crucial role in inflammation. Additionally, the anti-inflammatory activities of CXCR4 antagonists were discussed. The findings might help generate new perspectives for developing anti-inflammatory drugs targeting the CXCR4/CXCL12 axis.

KDM6B drives epigenetic reprogramming associated with lymphoid stromal cell early commitment and immune properties

Mature lymphoid stromal cells (LSCs) are key organizers of immune responses within secondary lymphoid organs. Similarly, inflammation-driven tertiary lymphoid structures depend on immunofibroblasts producing lymphoid cytokines and chemokines. Recent studies have explored the origin and heterogeneity of LSC/immunofibroblasts, yet the molecular and epigenetic mechanisms involved in their commitment are still unknown. This study explored the transcriptomic and epigenetic reprogramming underlying LSC/immunofibroblast commitment. We identified the induction of lysine demethylase 6B (KDM6B) as the primary epigenetic driver of early immunofibroblast differentiation. In addition, we observed an enrichment for KDM6B gene signature in murine inflammatory fibroblasts and pathogenic stroma of patients with autoimmune diseases. Last, KDM6B was required for the acquisition of LSC/immunofibroblast functional properties, including the up-regulation of CCL2 and the resulting recruitment of monocytes. Overall, our results reveal epigenetic mechanisms that participate in the early commitment and immune properties of immunofibroblasts and support the use of epigenetic modifiers as fibroblast-targeting strategies in chronic inflammation.

The Mechanisms and Efficacy of Photobiomodulation Therapy for Arthritis: A Comprehensive Review

Rheumatoid arthritis (RA) and osteoarthritis (OA) have a significant impact on the quality of life of patients around the world, causing significant pain and disability. Furthermore, the drugs used to treat these conditions frequently have side effects that add to the patient's burden. Photobiomodulation (PBM) has emerged as a promising treatment approach in recent years. PBM effectively reduces inflammation by utilizing near-infrared light emitted by lasers or LEDs. In contrast to photothermal effects, PBM causes a photobiological response in cells, which regulates their functional response to light and reduces inflammation. PBM's anti-inflammatory properties and beneficial effects in arthritis treatment have been reported in numerous studies, including animal experiments and clinical trials. PBM's effectiveness in arthritis treatment has been extensively researched in arthritis-specific cells. Despite the positive results of PBM treatment, questions about specific parameters such as wavelength, dose, power density, irradiation time, and treatment site remain. The goal of this comprehensive review is to systematically summarize the mechanisms of PBM in arthritis treatment, the development of animal arthritis models, and the anti-inflammatory and joint function recovery effects seen in these models. The review also goes over the evaluation methods used in clinical trials. Overall, this review provides valuable insights for researchers investigating PBM treatment for arthritis, providing important references for parameters, model techniques, and evaluation methods in future studies.

The chemokines CXCL8 and CXCL12: molecular and functional properties, role in disease and efforts towards pharmacological intervention

Chemokines are an indispensable component of our immune system through the regulation of directional migration and activation of leukocytes. CXCL8 is the most potent human neutrophil-attracting chemokine and plays crucial roles in the response to infection and tissue injury. CXCL8 activity inherently depends on interaction with the human CXC chemokine receptors CXCR1 and CXCR2, the atypical chemokine receptor ACKR1, and glycosaminoglycans. Furthermore, (hetero)dimerization and tight regulation of transcription and translation, as well as post-translational modifications further fine-tune the spatial and temporal activity of CXCL8 in the context of inflammatory diseases and cancer. The CXCL8 interaction with receptors and glycosaminoglycans is therefore a promising target for therapy, as illustrated by multiple ongoing clinical trials. CXCL8-mediated neutrophil mobilization to blood is directly opposed by CXCL12, which retains leukocytes in bone marrow. CXCL12 is primarily a homeostatic chemokine that induces migration and activation of hematopoietic progenitor cells, endothelial cells, and several leukocytes through interaction with CXCR4, ACKR1, and ACKR3. Thereby, it is an essential player in the regulation of embryogenesis, hematopoiesis, and angiogenesis. However, CXCL12 can also exert inflammatory functions, as illustrated by its pivotal role in a growing list of pathologies and its synergy with CXCL8 and other chemokines to induce leukocyte chemotaxis. Here, we review the plethora of information on the CXCL8 structure, interaction with receptors and glycosaminoglycans, different levels of activity regulation, role in homeostasis and disease, and therapeutic prospects. Finally, we discuss recent research on CXCL12 biochemistry and biology and its role in pathology and pharmacology.

G-Protein-Coupled Receptors in Rheumatoid Arthritis: Recent Insights into Mechanisms and Functional Roles

Rheumatoid arthritis (RA) is a chronic inflammatory disease that leads to joint damage and even disability. Although there are various clinical therapies for RA, some patients still have poor or no response. Thus, the development of new drug targets remains a high priority. In this review, we discuss the role of G-protein-coupled receptors (GPCRs), including chemokine receptors, melanocortin receptors, lipid metabolism-related receptors, adenosine receptors, and other inflammation-related receptors, on mechanisms of RA, such as inflammation, lipid metabolism, angiogenesis, and bone destruction. Additionally, we summarize the latest clinical trials on GPCR targeting to provide a theoretical basis and guidance for the development of innovative GPCR-based clinical drugs for RA.

Comparison of Romosozumab Versus Denosumab Treatment on Bone Mineral Density After One Year in Rheumatoid Arthritis Patients with Severe Osteoporosis: A Randomized Clinical Pilot Study

OBJECTIVES

To investigate the effect of romosozumab versus denosumab treatment on bone mineral density (BMD), disease activity, and joint damage in patients with rheumatoid arthritis (RA) and severe osteoporosis.

METHODS

Fifty-one postmenopausal women were enrolled and randomized equally into two groups to receive either romosozumab or the denosumab. Changes (Δ) in the BMD (at lumbar spine, total hip, and femoral neck), disease activity score in 28 joints (DAS28)-erythrocyte sedimentation rate (ESR), and van der Heijde-modified Total Sharp Score (TSS) from baseline to 12 months after treatment were evaluated.

RESULTS

The ΔBMD at 12 months in the romosozumab and denosumab groups were 10.2 ± 5.6% and 5.0 ± 3.1% (p = 0.002) for the lumbar spine, 3.7 ± 4.9% and 3.5 ± 3.0% (p = 0.902) for total hip, and 3.6 ± 4.7% and 3.2 ± 4.9% (p = 0.817) for femoral neck, respectively. The ΔDAS28-ESR at 12 months in the romosozumab and denosumab groups was 0.14 and 0.22 (p = 0.643), respectively, whereas, the ΔTSS at 12 months was 0.33 and 0.29 (p = 0.927), respectively.

CONCLUSIONS

Our results suggest that romosozumab treatment was more effective in increasing the BMD at the lumbar spine than denosumab, and may be selected for patients who require a significant increase in the lumbar spine BMD. Moreover, romosozumab may be not affect disease activity and joint damage in patients with RA.

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.

Anti-arthritis effect of berberine associated with regulating energy metabolism of macrophages through AMPK/ HIF-1α pathway

Berberine (BBR) is the effective constituent of Cortex phellodendri and was characterized as an excellent anti-microbial agent with significant anti-inflammatory effects. Previously, we had demonstrated that BBR alleviated the inflammatory response in adjuvant-induced arthritis (AA) rats by regulating polarization of macrophages. However, the exact mechanics by which BBR regulates macrophage polarization remained unclear. Here, we showed that BBR treatment had little influence on total number of macrophages in joints of AA rats, but increased the proportion of M2 macrophages and decreased the proportion of M1 macrophages. Meanwhile, we found BBR up-regulated the expression of AMP-activated protein kinase phosphorylation (p-AMPK) and down-regulated the expression of Hypoxia inducible factor 1α (HIF-1α) in synovial macrophages of AA rats. In vitro, using LPS-stimulated peritoneal macrophages from normal rats, we also verified that pretreatment with BBR promoted transition from M1 to M2 by up-regulating the expression of p-AMPK and suppressing the expression of HIF-1α. Compound C (an AMPK inhibitor) could abrogate the inhibition of BBR on migration of macrophages. Glycolysis of M1 suppressed by BBR through decreasing lactate export, glucose consumption, and increasing intracellular ATP content, which was remarkably reversed by Compound C. These findings indicated that anti-arthritis effect of BBR is associated with regulating energy metabolism of macrophages through AMPK/HIF-1α pathway.

Pharmacological targets of metabolism in disease: Opportunities from macrophages

From advances in the knowledge of the immune system, it is emerging that the specialized functions displayed by macrophages during the course of an immune response are supported by specific and dynamically-connected metabolic programs. The study of immunometabolism is demonstrating that metabolic adaptations play a critical role in modulating inflammation and, conversely, inflammation deeply influences the acquisition of specific metabolic settings.This strict connection has been proven to be crucial for the execution of defined immune functional programs and it is now under investigation with respect to several human disorders, such as diabetes, sepsis, cancer, and autoimmunity. The abnormal remodelling of the metabolic pathways in macrophages is now emerging as both marker of disease and potential target of therapeutic intervention. By focusing on key pathological conditions, namely obesity and diabetes, rheumatoid arthritis, atherosclerosis and cancer, we will review the metabolic targets suitable for therapeutic intervention in macrophages. In addition, we will discuss the major obstacles and challenges related to the development of therapeutic strategies for a pharmacological targeting of macrophage's metabolism.

The many facets of macrophages in rheumatoid arthritis

Macrophages are central to the pathophysiology of rheumatoid arthritis (RA). They constitute the main source of pro-inflammatory cytokines and chemokines such as TNF and IL-1β, they activate a wide range of immune and non-immune cells, and they secrete diverse tissue degrading enzymes driving chronic pro-inflammatory, tissue destructive and pain responses in RA. However, they can also produce anti-inflammatory cytokines such as IL-10, secrete inhibitors of tissue degrading enzymes and promote immunoregulatory and protective responses, suggesting the existence of macrophages with distinct and diverse functional activities. Although the underlying basis of this phenomenon has remained obscure for years, emerging evidence has now provided insight into the mechanisms and molecular processes involved. Here, we review current knowledge on the biology of macrophages in RA, and highlight recent literature on the heterogeneity, origins and ontogeny of macrophages as part of the mononuclear phagocyte system. We also discuss their plasticity in the context of the M1/M2 paradigm, and the emerging theme of metabolic rewiring as a major mechanism for programming macrophage functions and pro-inflammatory activities. This sheds light into the many facets of macrophages in RA, their molecular regulation and their translational potential for developing novel protective and therapeutic strategies in the clinic.

Comparison of rheumatoid arthritis (RA) and osteoarthritis (OA) based on microarray profiles of human joint fibroblast-like synoviocytes

The purpose of the present study was to investigate the underlying molecular mechanism of osteoarthritis (OA) and rheumatoid arthritis (RA) based on microarray profiles. Three human joint fibroblast-like synoviocytes (FLSs) microarray profiles including 26 OA samples, 33 RA samples, and 20 healthy control (HC) samples were downloaded from the GEO database. Differentially expressed genes (DEGs) between OA and HC (DEGsOA) and RA and HC (DEGsRA) were identified. Co-expressed and specific genes were analysed between DEGsOA and DEGsRA. Gene ontology, KEGG pathway enrichment, PPI network, and GSEA were performed to predict the function of DEGs. Two hundred seventy-six and 410 differential genes in DEGsOA and DEGsRA were observed. One hundred fifty coexpressed genes and 126 OA-specific genes (SELE, SERPINE1, and NFKBIA were the key genes) between DEGsOA and DEGsRA were enriched in the tumour necrosis factor (TNF) signalling pathway. However, 260 RA-specific genes of which the key genes were CCR5, CCR7, CXCR4, CCL5, and CCR4 were enriched in chemokine signalling pathway. Therefore, FLSs might exert an inflammatory effect by regulating TNF signalling pathway, targeting SELE, SERPINE1, and NFKBIA during the process of OA. Although TNF signalling pathway was also involved in the synovitis of RA, chemokine signalling pathway played the key role in RA FLSs mediating cell migration, invasion, and release of chemotaxis. In addition, CCR5, CCR7, CXCR4, CCL5, and CCR4 might be hub genes in RA. The different biomarkers and pathways identified in OA and RA may provide references for further study. SIGNIFICANCE OF THE STUDY: This study revealed the similar and different mechanisms of FLSs and different biomarkers that might with important regulatory effects on RA and OA. In OA, FLSs played an inflammatory role through TNF signalling pathway, targeting SELE, SERPINE1, and NFKBIA. Although TNF signalling pathway was also involved in the synovitis of RA, chemokine signalling pathway was a crucial pathway in mediating FLSs migration, invasion, and release of chemotaxis. CCR5, CCR7, CXCR4, CCL5, and CCR4 might be keys genes in RA. We expect that our results will bring more comprehensively understanding between RA and OA for researchers.