Frequency of IL-10-producing regulatory B cells associated with disease activity in thyroid-associated orbitopathy

Immune checkpoints: new insights into the pathogenesis of thyroid eye disease

Thyroid eye disease (TED) is a disfiguring autoimmune disease characterized by changes in the orbital tissues and is caused by abnormal thyroid function or thyroid-related antibodies. It is the ocular manifestation of Graves' disease. The expression of thyroid-stimulating hormone receptor (TSHR) and the insulin-like growth factor-1 receptor (IGF-1 R) on the cell membrane of orbital fibroblasts (OFs) is responsible for TED pathology. Excessive inflammation is caused when these receptors in the orbit are stimulated by autoantibodies. CD34+ fibrocytes, found in the peripheral blood and orbital tissues of patients with TED, express immune checkpoints (ICs) like MHC II, B7, and PD-L1, indicating their potential role in presenting antigens and regulating the immune response in TED pathogenesis. Immune checkpoint inhibitors (ICIs) have significantly transformed cancer treatment. However, it can also lead to the occurrence of TED in some instances, suggesting the abnormality of ICs in TED. This review will examine the overall pathogenic mechanism linked to the immune cells of TED and then discuss the latest research findings on the immunomodulatory role of ICs in the development and pathogenesis of TED. This will offer fresh perspectives on the study of pathogenesis and the identification of potential therapeutic targets.

Single-cell BCR and transcriptome analysis reveals peripheral immune signatures in patients with thyroid-associated ophthalmopathy

Thyroid-associated ophthalmopathy (TAO) is the most prevalent orbital disease in adults caused by an autoimmune disorder, which can lead to disfigurement and vision impairment. Developing effective treatments for this condition presents challenges due to our limited understanding of its underlying immune aberrations. In this study, we profiled the immune components in the peripheral blood of patients with TAO as well as healthy individuals, utilizing single-cell RNA sequencing and B-cell receptor repertoires (BCR) analysis. We observed a significant reduction in the proportions of regulatory B cells (Bregs) and type 2 conventional dendritic cells (DCs) in patients with TAO during the active phase. Conversely, there was a significant increase in the proportion of type 1 DCs. Further analysis of cell differentiation trajectory revealed potential impairment in the transition of B cells towards Breg phenotype during the active phase of TAO. Besides, the activation process of TAO appeared to involve inflammation and immune dysfunction, as indicated by the dynamic changes in the activities of key regulators. The abnormalities in the peripheral immune system, such as the reduced capacity of Bregs to suppress inflammation, were primarily driven by the enhanced interaction among Breg, DCs, and monocytes (i.e., CD22-PTPRC and BTLA-TNFRSF14). Collectively, our findings offer a comprehensive insight into the molecular regulation and cellular reconfiguration during the active phase of TAO at the single-cell level, in order to explore the pathogenesis of TAO and provide new ideas for the future treatment of TAO.

Puerarin inhibits inflammation and oxidative stress in female BALB/c mouse models of Graves' disease

Background

Graves' disease (GD) is an autoimmune thyroid disorder. Our previous study has demonstrated a significant decrease in flavone levels among children with GD compared to the control group. Puerarin, a well-known flavonoid with anti-inflammatory and antioxidant properties. We wanted to investigate its potential impact on GD pathogenesis, aiming to determine whether increasing puerarin intake could prevent or delay the onset of GD.

Methods

Adenovirus with TSHR-289 subunit was used to establish a GD mice model, and mice were intragastrically administered with puerarin or sterilized water daily. Thyroid function and inflammatory cytokine levels were quantified using ELISA, lymphocyte subsets were analyzed via flow cytometry, oxidative stress (OS) markers were measured with a microplate reader, and the expression of pertinent signaling pathway proteins were assessed by Western blot.

Results

The results demonstrated that puerarin treatment significantly decreased thyroxin levels and alleviated thyroid pathological changes in GD mice. Furthermore, the immune imbalance of GD mice was improved, as evidenced by reduced inflammatory indexes, elevated antioxidant levels, and decreased malondialdehyde (MDA) levels compared to untreated GD mice. Puerarin-treated GD mice exhibited significantly lower expressions of heat shock protein (HSP): HSP70, HSP90, phosphorylated extracellular regulated kinases (p-ERK) and phosphorylated protein kinase B (p-AKT) than untreated GD mice. Moreover, low dosage puerarin (400 mg/kg) was associated with a better protective effect than high dosage (1,200 mg/kg).

Conclusions

Puerarin may have the potential to mitigate GD by inhibiting inflammatory and OS, through downregulating the expression of HSP70 and HSP90 and suppressing the activation of the PI3K/AKT/ERK signaling pathway. Furthermore, a lower dose exhibited superior protective effects compared to a higher dose.

Advances of Regulatory B Cells in Autoimmune Diseases

With the ability to induce T cell activation and elicit humoral responses, B cells are generally considered as effectors of the immune system. However, the emergence of regulatory B cells (Bregs) has given new insight into the role of B cells in immune responses. Bregs exhibit immunosuppressive functions via diverse mechanisms, including the secretion of anti-inflammatory cytokines and direct cell contact. The balance between Bregs and effector B cells is important for the immune tolerance. In this review, we focus on recent advances in the characteristics of Bregs and their functional roles in autoimmunity.