Autoantigen signalling through chemokine receptors

Efficacy of traditional Chinese exercise for the treatment of pain and disability on knee osteoarthritis patients: a systematic review and meta-analysis of randomized controlled trials

Objective

To evaluate the efficacy of Traditional Chinese Exercises (TCEs) in treating knee osteoarthritis (KOA).

Methods

Four databases without language or publication status restrictions were searched until April 1, 2022. Based on the principle of Population, Intervention, Comparison, Outcomes and Study design, the researchers searched for randomized controlled trials of TCEs in treating KOA. The Western Ontario and McMaster Universities Osteoarthritis (WOMAC) pain was defined as the primary outcome, whereas stiffness and physical function were the secondary outcomes. Subsequently, two researchers conducted the process independently, and the data were analyzed using the RevManV.5.3 software.

Results

Overall, 17 randomized trials involving 1174 participants met the inclusion criteria. The synthesized data of TCEs showed a significant improvement in WOMAC pain score [standardized mean difference (SMD) = -0.31; 95% confidence interval (CI): -0.52 to -0.10; p = 0.004], stiffness score (SMD = -0.63; 95% CI: -1.01 to -0.25; p = 0.001) and physical function score (SMD = -0.38; 95% CI: -0.61 to -0.15; p = 0.001) compared with the control group. Sensitivity analyses were performed to determine the combined results' stability, which was unstable after excluding articles with greater heterogeneity. A further subgroup analysis showed that it might be the reason for the heterogeneity of the different traditional exercise intervention methods. Additionally, it showed that the Taijiquan group improved pain (SMD = 0.74; 95% CI: -1.09 to 0.38; p < 0.0001; I2 = 50%), stiffness (SMD = -0.67; 95% CI -1.14 to 0.20; p = 0.005) and physical function score (SMD = -0.35; 95% CI: -0.54 to 0.16; p = 0.0003; I2 = 0%) better than the control group. The Baduanjin group improved stiffness (SMD = -1.30; 95% CI: -2.32 to 0.28; p = 0.01) and physical function (SMD = -0.52; 95% CI: -0.97 to 0.07; p = 0.02) better than the control group. However, the other interventions showed no difference compared with the control group.

Conclusion

This systematic review provides partial evidence of the benefits of TCEs for knee pain and dysfunction. However, due to the heterogeneity of exercise, more high-quality clinical studies should be conducted to verify the efficacy.

Systematic review registration

https://inplasy.com/inplasy-2022-4-0154/, identifier: International Platform of Registered Systematic Review and Meta-analysis Protocols (INPLASY) [INPLSY202240154].

IL-6 alters migration capacity of CD4+Foxp3+ regulatory T cells in systemic lupus erythematosus

Regulatory T cells (Tregs) are impaired in human systemic lupus erythematosus (SLE) and involved in disease pathogenesis. However, the mechanisms responsible for the Treg dysfunction in SLE remain unclear. In this study, we aimed to investigate the chemotaxis of Treg response to inflammatory stimulation. Sixty two patients were enrolled, and chemokine receptors, including CCR4, CCR5, CCR6, CCR8 and CXCR3 on CD4+Foxp3+Tregs and non-Treg CD4 T cells, were analysed using FACS. The expression of CCR4 and CCR6 on Tregs of SLE patients decreased, while the expression of CCR4 on non-Treg CD4 T cells increased, as compared with those of age- and sex-matched healthy donors. In parallel, in SLE, the chemotactic capacity of non-Treg CD4 T cells response to CCR4 and CCR6 ligands dramatically increased, while that of Tregs significantly decreased. Moreover, we found that cytokines IL-6 and IL-10 positively and negatively modulate the expression of those receptors respectively. IL-6, the significantly increased cytokine in active SLE, dramatically elevated CCR4 and CCR6 expression on non-Treg CD4 T cells. However, as for Tregs, these cells produced more IL-10 than non-Treg CD4 T cells upon IL-6 stimulation, and these IL-10 led to the inhibition of CCR4 and CCR6. In sum, our data provided new evidence suggesting a functional deficiency of Tregs in SLE. It may suggest that those dysfunctional Tregs have less access to the inflammation locus to exert inhibitory capacity.

Acupotomy Therapy for Knee Osteoarthritis Pain: Systematic Review and Meta-Analysis

Methods

We performed a comprehensive search on PubMed, the Cochrane Library, EMBASE, and four Chinese databases for articles published prior to June 2020. We included only randomized controlled trials (RCTs) that used acupotomy therapy as the major intervention in adults with knee OA, were published in either Chinese and English, included more than 20 subjects in each group, and included pain and function in the outcome measures. Knee OA was defined by the American College of Rheumatology or Chinese Orthopedic Association criteria in all studies. We extracted the visual analogue scale (VAS) pain score, the Western Ontario and McMaster Universities Osteoarthritis Index (WOMAC) pain score, the total effectiveness rate, the modified Japanese Orthopedic Association (JOA) activities of daily living score, and Lysholm's score. We calculated the mean difference (MD) or risk ratio (RR) for all relevant outcomes. Meta-analyses were conducted using random-effects models when appropriate.

Results

We identified 1317 potentially relevant studies, thirty-two of which met the eligibility criteria and were conducted in China between 2007 and 2020. A total of 3021 knee OA patients (62.96% female, median age: 57 years, and median disease duration: 33 months) were included. The treatment duration ranged from 1 week to 5 weeks (median: 3 weeks). The typical acupotomy treatment involved releasing soft tissue adhesions and was performed once a week for 1–5 weeks until the pain was relieved. The control group treatments included acupuncture (8 studies), electroacupuncture (10 studies), sodium hyaluronate (8 studies), radiofrequency electrotherapy (1 study), and nonsteroidal anti-inflammatory drugs (NSAIDs, 5 studies). The results from the meta-analysis showed that acupotomy led to superior improvements in the VAS pain score (MD = −1.11; 95% confidence interval (CI), −1.51 to −0.71; p < 0.00001) and WOMAC pain score (MD = −2.32; 95% CI, −2.94 to −1.69; p < 0.00001), a higher total effectiveness rate (RR = 1.15; 95% CI, 1.09–1.21; p < 0.00001), and superior improvements in the JOA score (MD = 6.39; 95% CI, 4.11–9.76; p < 0.00001) and Lysholm's score (MD = 12.75; 95% CI, 2.61–22.89; p = 0.01) for overall pain and function. No serious adverse events were reported.

Conclusion

Chinese acupotomy therapy may relieve pain and improve function in patients with knee OA. Furthermore, rigorously designed and well-controlled RCTs are warranted.

Antibodies against specific extractable nuclear antigens (ENAs) as diagnostic and prognostic tools and inducers of a profibrotic phenotype in cultured human skin fibroblasts: are they functional?

BACKGROUND

The importance of systemic sclerosis (SSc) autoantibodies for diagnosis has become recognized by their incorporation into the 2013 ACR/EULAR classification criteria. Clear prognostic and phenotypic associations with cutaneous subtype and internal organ involvement have been also described. However, little is known about the potential of autoantibodies to exert a direct pathogenic role in SSc. The aim of the study is to assess the pathogenic capacity of anti-DNA-topoisomerase I (anti-Topo-I) and anti-centromeric protein B (anti-Cenp-B) autoantibodies to induce pro-fibrotic markers in dermal fibroblasts.

METHODS

Dermal fibroblasts were isolated from unaffected and affected skin samples of (n = 10) limited cutaneous SSc (LcSSc) patients, from affected skin samples of diffuse cutaneous (DcSSc) patients (n = 10) and from healthy subjects (n = 20). Fibroblasts were stimulated with anti-Topo-I, anti-Cenp-B IgGs, and control IgGs in ratios 1:100 and 1:200 for 24 h. Cells were also incubated with 10% SSc anti-Topo-I+ and anti-Cenp-B+ whole serum and with 10% control serum for 24 h. Viability was assessed by MTT test, while apoptosis was assessed by flow cytometry. Activation of pro-fibrotic genes ACTA2, COL1A1, and TAGLN was evaluated by quantitative real-time PCR (qPCR), while the respective protein levels alpha-smooth-muscle actin (α-SMA), type-I-collagen (Col-I), and transgelin (SM22) were assessed by immunocytochemistry (ICC).

RESULTS

MTT showed that anti-Cenp-B/anti-Topo-I IgGs and anti-Cenp-B+/anti-Topo-I+ sera reduced viability (in a dilution-dependent manner for IgGs) for all the fibroblast populations. Apoptosis is induced in unaffected LcSSc and control fibroblasts, while affected LcSSc/DcSSc fibroblasts showed apoptosis resistance. Basal mRNA (ACTA2, COL1A1, and TAGLN) and protein (α-SMA, Col-1, and SM22) levels were higher in affected LcSSc/DcSSc fibroblasts compared to LcSSc unaffected and to control ones. Stimulation with anti-Cenp-B/anti-Topo-I IgGs and with anti-Cenp-B+/anti-Topo-I+ sera showed a better induction in unaffected LcSSc and control fibroblasts. However, a statistically significant increase of all pro-fibrotic markers is reported also in affected LcSSc/DcSSc fibroblasts upon stimulation with both IgGs and sera.

CONCLUSIONS

This study suggests a pathogenic role of SSc-specific autoantibodies to directly induce pro-fibrotic activation in human dermal fibroblasts. Therefore, besides the diagnostic and prognostic use of those autoantibodies, these data might further justify the importance of immunosuppressive drugs in the early stages of the autoimmune disease, including SSc.

Sjögren's Syndrome Antigen B Acts as an Endogenous Danger Molecule to Induce Interleukin-8 Gene Expression in Polymorphonuclear Neutrophils

BACKGROUND

Sjögren's syndrome antigen B is expressed in the nucleus and surface membrane of human polymorphonuclear neutrophils and is released after cell death. However, its biological role is not clear. This study is aimed to investigate the effect of Sjögren's syndrome antigen B on human polymorphonuclear neutrophils.

METHODS

Human recombinant Sjögren's syndrome antigen B (rSSB) purified from E. coli was incubated with human polymorphonuclear neutrophils as well as retinoid acid-induced granulocytic differentiated HL-60 cells, HL-60 (RA). Interleukin (IL)-8 protein production and mRNA expressions were measured by enzyme-linked immunosorbent assay and quantitative-polymerase chain reaction, respectively. Uptake of fluorescein isothiocyanate (FITC)-rSSB was assessed by flow cytometry and fluorescence microscopy. Moreover, mitogen-activated protein kinase (MAPK) pathways and nuclear factor-kappaB activation were investigated.

RESULTS

Human rSSB stimulated IL-8 production from normal human neutrophils and HL-60 (RA) cells in a time- and dose-dependent manner. This IL-8-stimulated activity was blocked by chloroquine and NH4Cl, indicating that endosomal acidification is important for this effect. We found rSSB activated both MAPK pathway and nuclear factor-kappaB signaling to transcribe the IL-8 gene expression of cells. Furthermore, tumor necrosis factor-α exerted an additive effect and rSSB-anti-SSB immune complex exhibited a synergistic effect on rSSB-induced IL-8 production.

CONCLUSIONS

Sjögren's syndrome antigen B might act as an endogenous danger molecule to enhance IL-8 gene expression in human polymorphonuclear neutrophils.

The autoantigen DNA topoisomerase I interacts with chemokine receptor 7 and exerts cytokine-like effects on dermal fibroblasts

OBJECTIVE

Previous studies have demonstrated that, once released into the extracellular environment, the systemic sclerosis (SSc)-associated autoantigen DNA topoisomerase I (topo I) binds specifically to the surface of fibroblasts via an unknown receptor. We extended these results by identifying topo I-mediated cellular effects and characterizing the specific target of topo I on fibroblast surfaces.

METHODS

Purified topo I was used to investigate intracellular signaling pathway activation and tested for cell migration. To demonstrate the expression of specific chemokine receptors on fibroblasts, we performed immunoblotting and flow cytometry. To evaluate the direct interaction between chemokine receptor and topo I, a protein-protein based enzyme-linked immunosorbent assay (ELISA) was used. Finally, topo I coupled to the fluorochrome phycoerythrin (PE) was used to investigate competition of topo I specific binding on fibroblast surfaces with chemokine ligand.

RESULTS

Topo I stimulated the phosphorylation of phospholipase Cγ1, c-Raf, ERK-1/2, and p38 MAPK, intracellular signaling pathways that stimulated fibroblast migration via a G(αi) protein-coupled receptor. CCR7 was found to interact directly with topo I. Furthermore, its ligand, CCL21, competed in vitro for this interaction and in vivo with the binding of PE-coupled topo I to fibroblast surfaces.

CONCLUSION

These new roles of topo I in fibroblast physiology and the identification of its target on the cell surface demonstrate that topo I is a bifunctional autoantigen and open up new perspectives of study in the field of SSc-associated anti-topo I autoantibodies.

Nuclear autoantigen CENP-B transactivation of the epidermal growth factor receptor via chemokine receptor 3 in vascular smooth muscle cells

OBJECTIVE

We have previously found that the CENP-B nuclear autoantigen, which is specifically targeted by autoantibodies in the limited cutaneous form of systemic sclerosis, behaved as a potent migratory factor for human pulmonary artery smooth muscle cells (PASMCs). Other recent studies have shown that several disease-associated autoantigens induced cell migration by interacting with various chemokine receptors. Prompted by this hypothesis, we undertook this study to determine whether CENP-B interacts with chemokine receptors on the surface of human PASMCs, to explore the relevant signaling pathways, and to characterize the effects of anti-CENP-B binding on SMC stimulation.

METHODS

To demonstrate the expression of specific chemokine receptors by human PASMCs at both the messenger RNA and protein levels, reverse transcription-polymerase chain reaction, immunoblotting, and flow cytometry analyses were performed. Desensitization studies and specific inhibitors were used to further identify the CENP-B target on the surface of human PASMCs.

RESULTS

Our data strongly suggested that CENP-B used chemokine receptor 3 (CCR3) to mediate human PASMCs signaling. Moreover, several lines of evidence indicated that CENP-B binding subsequently stimulated the cross-talk between CCR3 and epidermal growth factor receptor (EGFR) via a matrix metalloprotease-dependent mechanism that involved the processing of heparin-binding EGF-like growth factor. Transactivation of the EGFR through CCR3 was found to be a critical pathway that elicits MAP kinase activation and secretion of cytokines such as interleukin-8. Finally, anti-CENP-B autoantibodies were found to abolish this signaling pathway, thus preventing CENP-B from transactivating EGFR and exerting its cytokine-like activities toward vascular smooth muscle cells.

CONCLUSION

The identification of CENP-B as a CCR3 ligand opens up new perspectives for the study of the pathogenic role of anti-CENP-B autoantibodies.