Increased Th17 cells in flow cytometer-sorted CD45RO-positive memory CD4 T cells from patients with systemic lupus erythematosus

CD4+ T-cell cooperation promoted pathogenic function of activated naïve B cells of patients with SLE

Objective

To explore cooperation between activated naïve (aNAV) B cells and CD4⁺ T cells in the pathogenesis of SLE through autoantibody production, T-cell differentiation and inflammatory cytokine secretion.

Methods

Peripheral blood mononuclear cell samples were obtained from 31 patients with SLE and used to characterise phenotype of aNAV B cells (n=14) and measured the phosphorylation of B-cell receptor (BCR) signalling molecules (n=5). Upregulation of T-cell costimulatory molecules after BCR and toll-like receptor (TLR)-7/TLR-8 stimulation was detected in cells from four subjects. To explore the role of these cells in SLE pathogenesis via T cell-dependent mechanisms, four subjects were analysed to detect the promotion of CD4⁺ T-cell activation and antibody-secreting cell (ASC) differentiation after CD4⁺ T-cell–B-cell cocultures. The aNAV B cells from four patients were used to assess cytokine secretion.

Results

The aNAV B cells of patients with SLE had increased expression of surface CD40, HLA-DR and interleukin-21 receptor (IL-21R) and FCRL5 molecules. With BCR stimulation, these cells greatly increased PLCγ2 phosphorylation. Integrated BCR and TLR-7/TLR-8 signals induced overexpression of CD40, CD86, IL-21R and HLA-DR on lupus aNAV B cells. In T-cell–B-cell cocultures, lupus aNAV B cells (with upregulated costimulatory molecules) promoted CD4⁺ T-cell proliferation and polarisation toward effector Th₂ and Th₁₇ cells. Importantly, in this coculture system, CD4⁺ T-cell signals enhanced aNAV B-cell differentiation into auto-ASCs and produced anti-DNA antibodies. The interaction between CD4⁺ T cell and aNAV B cell increased production of inflammatory cytokines (IL-6, IL-8 and IL-23).

Conclusion

Cooperation between aNAV B cells and CD4⁺ T cells contributed to SLE pathogenesis by promoting both differentiation of pathogenic T cells (Th₂ and Th₁₇) and autoantibody secretion.

Down-regulated miR-146a expression with increased neutrophil extracellular traps and apoptosis formation in autoimmune-mediated diffuse alveolar hemorrhage

BACKGROUND

Increasing evidences have suggested an important role of microRNAs (miRNAs) in regulating cell death processes including NETosis and apoptosis. Dysregulated expression of miRNAs and increased formation of neutrophil extracellular traps (NETs) and apoptosis participate in autoimmune-mediated diffuse alveolar hemorrhage (DAH), mostly associated with pulmonary capillaritis in systemic lupus erythematosus (SLE) patients. In particular, besides the inhibition of apoptosis, miR-146a can control innate and acquired immune responses, and regulate the toll-like receptor pathway through targeting TRAF6 to reduce the expression of pro-inflammatory cytokines/chemokines like IL-8, a NETosis inducer.

METHODS

Expression of miR-146a, TRAF6 and NETs were examined in peripheral blood neutrophils (PBNs) and lung tissues from SLE-associated DAH patients, and in neutrophils and pristane-induced DAH lung tissues from C57BL/6 mice. To assess NETs formation, we examined NETosis-related DNAs morphology and crucial mediators including protein arginine deiminase 4 and citrullinated Histone 3. Expression of miR-146a and its endogenous RNA SNHG16 were studied in HL-60 promyelocytic cells and MLE-12 alveolar cells during NETosis and apoptosis processes, respectively. MiR-146a-overexpressed and CRISPR-Cas13d-mediated SNHG16-silenced HL-60 cells were investigated for NETosis. MiR-146a-overexpressed MLE-12 cells were analyzed for apoptosis. Pristane-injected mice received intra-pulmonary miR-146a delivery to evaluate therapeutic efficacy in DAH.

RESULTS

In DAH patients, there were down-regulated miR-146a levels with increased TRAF6 expression and PMA/LPS-induced NETosis in PBNs, and down-regulated miR-146a levels with increased TRAF6, high-mobility group box 1 (HMGB1), IL-8, NETs and apoptosis expression in lung tissues. HMGB1-stimulated mouse neutrophils had down-regulated miR-146a levels with increased TRAF6, IL-8 and NETs expression. PMA-stimulated HL-60 cells had down-regulated miR-146a levels with enhanced NETosis. MiR-146a-overexpressed or SNHG16-silenced HL-60 cells showed reduced NETosis. Apoptotic MLE-12 cells had down-regulated miR-146a expression and increased HMGB1 release, while miR-146a-overexpressed MLE-12 cells showed reduced apoptosis and HMGB1 production. There were down-regulated miR-146a levels with increased TRAF6, HMGB1, IL-8, NETs and apoptosis expression in mouse DAH lung tissues. Intra-pulmonary miR-146a delivery could suppress DAH by reducing TRAF6, IL-8, NETs and apoptosis expression.

CONCLUSIONS

Our results demonstrate firstly down-regulated pulmonary miR-146a levels with increased TRAF6 and IL-8 expression and NETs and apoptosis formation in autoimmune-mediated DAH, and implicate a therapeutic potential of intra-pulmonary miR-146a delivery.

The Role of Autophagy in the Function of CD4+ T Cells and the Development of Chronic Inflammatory Diseases

Uncontrolled acute inflammation progresses to persistent inflammation that leads to various chronic inflammatory diseases, including asthma, Crohn’s disease, rheumatoid arthritis, multiple sclerosis, and systemic lupus erythematosus. CD4⁺ T cells are key immune cells that determine the development of these chronic inflammatory diseases. CD4⁺ T cells orchestrate adaptive immune responses by producing cytokines and effector molecules. These functional roles of T cells vary depending on the surrounding inflammatory or anatomical environment. Autophagy is an important process that can regulate the function of CD4⁺ T cells. By lysosomal degradation of cytoplasmic materials, autophagy mediates CD4⁺ T cell-mediated immune responses, including cytokine production, proliferation, and differentiation. Furthermore, through canonical processes involving autophagy machinery, autophagy also contributes to the development of chronic inflammatory diseases. Therefore, a targeted intervention of autophagy processes could be used to treat chronic inflammatory diseases. This review focuses on the role of autophagy via CD4⁺ T cells in the pathogenesis and treatment of such diseases. In particular, we explore the underlying mechanisms of autophagy in the regulation of CD4⁺ T cell metabolism, survival, development, proliferation, differentiation, and aging. Furthermore, we suggest that autophagy-mediated modulation of CD4⁺ T cells is a promising therapeutic target for treating chronic inflammatory diseases.

Panax notoginseng saponins reverse P-gp-mediated steroid resistance in lupus: involvement in the suppression of the SIRT1/FoxO1/MDR1 signalling pathway in lymphocytes

Background

P-glycoprotein (P-gp)-mediated steroid resistance (SR) has been suggested to play a significant role in lupus nephritis (LN) treatment failure. Panax notoginseng saponins (PNS), the main effective components of the traditional Chinese medicine notoginseng, exhibited potent reversal capability of P-gp-mediated SR, but its mechanism remains unknown. This study aimed to investigate the effect of PNS on reversing SR in lupus and its underlying mechanism in vivo and in vitro.

Methods

In this study, an SR animal and splenic lymphocyte model were established using low-dose methylprednisolone (MP). Flow cytometry was used to detect the effect of PNS on reversing P-gp-mediated SR and the expression of P-gp in different T-cells phenotypes. Serum levels of ANA and dsDNA in lupus mice were measured by ELISA. Apoptosis was identified by Annexin V-FITC/PI staining. RT–PCR and Western blotting were used to detect the protein and mRNA expression levels of SIRT1, FoxO1, and MDR1 in SR splenic lymphocytes from lupus mice (SLCs/MPs).

Results

PNS could reverse the SR in lupus mice. Simultaneously, PNS increased the apoptotic effect of MP on SLCs/MP cells. The increased accumulation of rhodamine-123 (Rh-123) indicated that intracellular steroid accumulation could be increased by the action of PNS. Moreover, PNS decreased the expression of P-gp levels. Further experiments elucidated that the SIRT1/FoxO1/MDR1 signalling pathway existed in SLCs/MP cells, and PNS suppressed its expression level to reverse SR. The expression of P-gp in Th17 from SLCs/MP cells was increased, while PNS could reduce its level in a more obvious trend.

Conclusion

The present study suggested that PNS reversed P-gp-mediated SR via the SIRT1/FoxO1/MDR1 signalling pathway, which might become a valuable drug for the treatment of SR in lupus. Th17 might be the main effector cell of PNS reversing SR.

Supplementary Information

The online version contains supplementary material available at 10.1186/s12906-021-03499-5.

Th17 cell differentiation induced by cytopathogenic biotype BVDV-2 in bovine PBLCs

Background

Bovine viral diarrhea virus (BVDV) is a major pathogen that causes bovine viral diarrhea/mucosal disease (BVD-MD), which has become a global infectious disease due to its wide spread and the lack of effective treatment. The process of BVDV infection is complex. Once infected, host immune cells are activated and modulated. As a major immune cell, peripheral blood lymphocyte cells (PBLCs) are the primary target of BVDV. In order to further understand the mechanism of BVDV- host interaction, the expression profiles of host lymphocytes mRNAs associated with BVDV infection were investigated by transcriptomic sequencing analysis.

Results

The transcriptomic sequencing analysis was performed on bovine PBLCs infected with CP BVDV-2 GS2018 after 12 h of infection. Gene expression profiling demonstrated that 1052 genes were differentially expressed in GS2018 infected PBLCs compared with the control group. Of these genes, 485 genes were up-regulated and 567 were down-regulated. The 19 differential expressed genes (DEGs) were selected for validation using quantitative real-time PCR and the results were consistent with the results of RNA-Seq. Gene ontology enrichment and KEGG pathway analysis showed that 1052 DEGs were significantly enriched in 16 pathways, including cytokine-cytokine receptor interaction, IL17, PI3K-Akt, MAPK and TNF signaling pathway. PPI network analysis showed that IL17A, IFN-γ and TNF-α interacted with various proteins and may play crucial roles in BVDV-2 infection. Of note, we confirmed that GS2018 induced Th17 cell differentiation in PBLCs and persistently increased the expression levels of IL17A. In turn, the replication of GS2018 was inhibited by IL17A.

Conclusion

In this study, the transcription changes of DEGs related to host immune responses in bovine PBLCs were caused by CP BVDV-2 infection. In particular, the effector molecules IL17A of Th17 cells were significantly up-regulated, which inhibited viral replication. These results will contribute to exploration and further understanding of the host immune response mechanism and interaction between host and BVDV-2.

Supplementary Information

The online version contains supplementary material available at 10.1186/s12864-021-08194-w.

Molecular mechanisms of glucocorticoid resistance in systemic lupus erythematosus: A review

The treatment of systemic lupus erythematosus (SLE) with glucocorticoids (GCs) is quite effective; however, GC resistance or insensitivity is a major barrier to the treatment of SLE. Therefore, it is necessary to identify the underlying mechanisms that lead to GC resistance. Much evidence shows that the mechanism of GC resistance is very complicated. GC receptor is involved in the main mechanism of GC resistance and was illustrated by a lot of literature. Therefore, this paper focuses on the GC resistance mechanisms of non-glucocorticoids receptor, including P-gp, MIF, TLR9, and Th17 cells. These molecular mechanisms may help diagnose GC resistance and provide an alternative treatment strategy to reverse GC resistance by blocking the underlying mechanisms.

The T helper type 17/regulatory T cell paradigm in pregnancy

T helper type 17 (Th17) and regulatory T (Treg) cells are active players in the establishment of tolerance and defence. These attributes of the immune system enmesh to guarantee the right level of protection. The healthy immune system, on the one hand, recognizes and eliminates dangerous non-self pathogens and, on the other hand, protects the healthy self. However, there are circumstances where this fine balance is disrupted. In fact, in situations such as in pregnancy, the foreign fetal antigens challenge the maternal immune system and Treg cells will dominate Th17 cells to guarantee fetal survival. In other situations such as autoimmunity, where the Th17 responses are often overwhelming, the immune system shifts towards an inflammatory profile and attacks the healthy tissue from the self. Interestingly, autoimmune patients have meliorating symptoms during pregnancy. This connects with the antagonist role of Th17 and Treg cells, and their specific profiles during these two immune challenging situations. In this review, we put into perspective the Th17/Treg ratio during pregnancy and autoimmunity, as well as in pregnant women with autoimmune conditions. We further review existing systems biology approaches that study specific mechanisms of these immune cells using mathematical modelling and we point out possible future directions of investigation. Understanding what maintains or disrupts the balance between these two opponent yet reciprocal cells in healthy physiological settings, sheds light into the development of innovative pharmacological approaches to fight pregnancy loss and autoimmunity.

Rituximab usage in systemic lupus erythematosus-associated antiphospholipid syndrome: A single-center experience

OBJECTIVES

Although the data from primary antiphospholipid syndrome (APS) suggests a beneficial effect of rituximab usage, its therapeutic role remains to be defined in systemic lupus erythematosus (SLE)-associated APS, a complex clinical situation with thrombotic events and lupus activity.

METHODS

A single-center retrospective analysis of rituximab usages in APS was performed in 800 hospitalized SLE patients.

RESULTS

There were 63 SLE-associated APS cases with 6 on rituximab therapy, all female aged 37.7 ± 9.0 years with 1 catastrophic and 16 thrombotic episodes. Therapeutic indications included warfarin failure despite the adequate target international normalized ratio with an average duration of 17.3 ± 11.2 months between the thrombotic recurrences. After the rituximab therapy, there was no relapse of thrombosis with a mean follow-up period of 39.3 ± 20.9 months, and a decrease in lupus activity (SLEDAI-2K, 9.7 ± 5.5 to 5.3 ± 2.2). Infection complications were observed, including episodes of bronchitis and urinary tract infection.

CONCLUSIONS

In this single-center study with largest case numbers and a long-term follow-up period, there were no recurrent thrombotic events after the rituximab therapy, implicating further consideration of large-scale trials enrolling more ethnic groups to evaluate its therapeutic role in SLE-associated APS patients.

The role of icaritin in regulating Foxp3/IL17a balance in systemic lupus erythematosus and its effects on the treatment of MRL/lpr mice

Systemic lupus erythematosus (SLE) is a female predominant autoimmune disease characterized by multi-organ dysfunctions. However, current available therapies control the disease at the cost of many potential adverse effects. The development of safer and more effective therapies for SLE is a critical unmet need. Icaritin (ICT) is an active monomer extracted from Chinese herbals named the Epimedium genus. In this study, we found that ICT exhibited the capacity of regulating Foxp3/IL17a balance, enhancing Treg cell suppressive activities, and inhibiting over-activation of CD4(+)T cells from SLE. We also observed that ICT regulated Foxp3/IL17a balance by increasing STAT5b expression and histone methylation modification. Subsequent experiments further confirmed that ICT-treated mice exhibited amelioration of renal damages and suggested that ICT may be a potential new drug for the treatment of SLE.