Chinese medicine Di-long (Pheretima vulgaris) and its active fraction exhibit anti-rheumatoid arthritis effects by inhibiting CXCL10/CXCR3 chemotaxis in synovium

ETHNOPHARMACOLOGICAL RELEVANCE

Di-Long (Pheretima vulgaris) is a classic animal sourced traditional Chinese medicine. It has been used for the treatment of joint inflammation and arthralgia for over two thousand years due to its effects of Tong-Luo-Zhi-Tong (dredging collaterals and alleviating pain). Our previous study showed that Chinese medicine Di-Long has significant anti-rheumatoid arthritis (RA) effects.

AIM OF THE STUDY

Considering Di-Long as a potential source of active compounds with specific anti-RA therapeutic effects, this research was to obtain the anti-RA target-specific active fraction from Di-Long extracts (DL), and to further explore the chemical basis and verify the anti-RA mechanism of this active fraction.

MATERIALS AND METHODS

Transcriptomic was applied to obtain the main anti-RA targets of DL on human RA fibroblast-like synoviocytes (FLS) and validated by qPCR. The target-corresponding active fraction was isolated from DL by ethanol precipitation and gel chromatography, and analyzed by nanoliter chromatography-mass spectrometry. Anti-RA effects of this active fraction was investigated by collagen-induced arthritis (CIA) in mice, and anti-RA mechanisms were verified in cocultured model of rat FLS and peripheral blood lymphocytes.

RESULTS

We confirmed that CXCL10/CXCR3 was the main anti-RA target of DL. The active fraction - A (2182 - 890 Da) was isolated from DL based on its CXCL10 inhibiting effects in RA-FLS. Fraction A contains 195 peptides (192 were newly discovered), 26 of which might be bioactive and were considered to be the chemical basis of its anti-RA effects. Fraction A significantly ameliorated the joint destruction and overall inflammation in CIA mice, and downregulated CXCR3 expression in mice joint. Fraction A inhibited the chemotaxis of Th-cells in rat peripheral blood lymphocytes towards the TNF-α-induced rat FLS through CXCL10/CXCR3 pathway.

CONCLUSIONS

Our work indicated that active fraction from DL containing small peptides exhibits promising therapeutic effects for RA through inhibiting CXCL10/CXCR3 chemotaxis.

Autophagy-mediated NKG2D internalization impairs NK cell function and exacerbates radiation pneumonitis

Introduction

Radiation pneumonitis is a critical complication that constrains the use of radiation therapy for thoracic malignancies, leading to substantial morbidity via respiratory distress and lung function impairment. The role of Natural killer (NK) cells in inflammatory diseases is well-documented; however, their involvement in radiation pneumonitis is not fully understood.

Methods

To explore the involvement of NK cells in radiation pneumonitis, we analyzed tissue samples for NK cell presence and function. The study utilized immunofluorescence staining, western blotting, and immunoprecipitation to investigate CXCL10 and ROS levels, autophagy activity, and NKG2D receptor dynamics in NK cells derived from patients and animal models subjected to radiation.

Result

In this study, we observed an augmented infiltration of NK cells in tissues affected by radiation pneumonitis, although their function was markedly diminished. In animal models, enhancing NK cell activity appeared to decelerate the disease progression. Concomitant with the disease course, there was a notable upsurge in CXCL10 and ROS levels. CXCL10 was found to facilitate NK cell migration through CXCR3 receptor activation. Furthermore, evidence of excessive autophagy in patient NK cells was linked to ROS accumulation, as indicated by immunofluorescence and Western blot analyses. The association between the NKG2D receptor and its adaptor proteins (AP2 subunits AP2A1 and AP2M1), LC3, and lysosomes was intensified after radiation exposure, as demonstrated by immunoprecipitation. This interaction led to NKG2D receptor endocytosis and subsequent lysosomal degradation.

Conclusion

Our findings delineate a mechanism by which radiation-induced lung injury may suppress NK cell function through an autophagy-dependent pathway. The dysregulation observed suggests potential therapeutic targets; hence, modulating autophagy and enhancing NK cell activity could represent novel strategies for mitigating radiation pneumonitis.

Icaritin inhibited cigarette smoke extract-induced CD8+ T cell chemotaxis enhancement by targeting the CXCL10/CXCR3 axis and TGF-β/Smad2 signaling

BACKGROUND

Chronic obstructive pulmonary disease (COPD) is a disabling/fatal disease characterized by progressive pulmonary function decline, and there are currently few drugs that can effectively reverse the decline in lung function; therefore, it is necessary to find novel drug targets. CD8⁺ T cells might be a new therapeutic target for alleviating lung tissue destruction and improving pulmonary function in COPD. The CXCL10/CXCR3 axis is a pivotal chemotactic axis involved in the abnormal infiltration of CD8⁺ T cells into the lung tissue of COPD; thus, inhibition of this axis might be a potential method to suppress CD8⁺ T cell-mediated lung tissue destruction in COPD. However, few drugs have been reported to target CD8⁺ T cells and the CXCL10/CXCR3 axis. Icaritin (ICT), one of the major components of Epimedii Folium, has been reported to have antioxidative effects in a COPD model in vitro. Whether ICT also has effects on CD8⁺ T cells and the CXCL10/CXCR3 axis in COPD has never been investigated.

PURPOSE

This study aimed to investigate the effects of ICT on CD8⁺ T cell chemotaxis and the CXCL10/CXCR3 axis in interferon (IFN)-γ + cigarette smoke extract (CSE)-stimulated THP-1-derived macrophages, which simulated the pulmonary microenvironment of COPD, and then to determine the mechanisms.

METHODS

The effects of ICT on the expression and secretion of CXCL9, CXCL10, and CXCL11 in THP-1-derived macrophages were measured by qRT-PCR and ELISA, and the effects of the supernatant of THP-1-derived macrophages treated with or without ICT on CD8⁺ T cell chemotaxis were also evaluated. Subsequently, the effects of ICT on the apoptosis and proliferation of CD8⁺ T cells were also assessed by EdU-488 assays and Annexin V/PI staining, respectively. Moreover, the mechanisms by which ICT inhibits the CXCL10/CXCR3 axis were investigated by RNA sequencing (RNA-seq) and KEGG pathway enrichment analysis.

RESULTS

The present study showed that ICT (5 μM) significantly suppressed the expression and secretion of CXCL9, CXCL10, and CXCL11 in THP-1-derived macrophages after stimulation with IFN-γ + CSE and indirectly inhibited CD8⁺ T cell chemotaxis by reducing the secretion of the above chemokines. In addition, this study found that ICT had no significant effect on the proliferation of CD8⁺ T cells, and neither led to apoptosis. The results of the RNA-seq analysis illustrated that the transforming growth factor (TGF)-β signaling pathway was significantly downregulated after ICT intervention, and subsequent qRT-PCR and western blotting showed that ICT could significantly downregulate the TGF-β-Smad2 signaling pathway.

CONCLUSIONS

ICT reduced CD8⁺ T cell chemotaxis by inhibiting the CXCL10/CXCR3 axis, and these effects might be achieved by suppressing the TGF-β-Smad2 signaling pathway.

TNF-α augments CXCL10/CXCR3 axis activity to induce Epithelial-Mesenchymal Transition in colon cancer cell

Chronic inflammation-induced metastases have long been regarded as one of the significant obstacles in treating cancer. Tumor necrosis factor-α (TNF-α), a main inflammation mediator within tumor microenvironment, affects tumor development by inducing multiple chemokines to establish a complex network. Recent reports have revealed that CXCL10/CXCR3 axis affects cancer cells invasiveness and metastases, and Epithelial-mesenchymal transition (EMT) is the main reason for frequent proliferation and distant organ metastases of colon cancer (CC) cells, However, it is unclear whether TNF-α- mediated chronic inflammation can synergically enhance EMT-mediated CC metastasis through promoting chemokine expression. According to this study, TNF-α activated the PI3K/Akt and p38 MAPK parallel signal transduction pathways, then stimulate downstream NF-κB pathway p65 into the nucleus to activate CXCL10 transcription. CXCL10 enhanced the metastases of CC-cells by triggering small GTPases such as RhoA and cdc42. Furthermore, overexpression of CXCL10 significantly enhanced tumorigenicity and mobility of CC cells in vivo. We further clarified that CXCL10 activated the PI3K/Akt pathway through CXCR3, resulting in suppression of GSK-3β phosphorylation and leading to upregulation of Snail expression, thereby regulating EMT in CC cells. These outcomes lay the foundation for finding new targets to inhibit CC metastases.