αvβ3 Integrin as a Link between the Development of Fibrosis and Thyroid Hormones in Systemic Sclerosis

Si-ITGA6-Loaded Liposomes Inhibit Capsule Fibrosis via the FAK/PI3K/Akt Signaling Pathway in Adhesive Capsulitis of Shoulder

Background

Adhesive capsulitis of shoulder (ACS) is a common shoulder disease with pain, joint stiffness, and capsule fibrosis. The pathogenesis of ACS remains unclear, and long-term efficacy of current treatment for ACS is not satisfactory. Given the absence of targeted therapy, proteomic analysis is conducted on the capsules of ACS patients, in an effort to identify the potential target for ACS treatment. The liposome-based siRNA delivery system was utilized for in vivo experiments due to its non-immunogenicity, stability, and low off-target effects compared to other siRNA delivery methods. We aimed to provide a potential approach for targeted therapy of ACS.

Methods

Capsules from rotator cuff tear (RCT) patients with or without ACS were collected. Proteomic analysis was performed to detect differentially expressed proteins. For in vitro experiments, EdU assay, wound healing assay, CCK-8, quantitative polymerase chain reaction, immunofluorescence staining and western blot was conducted. Histological, immunofluorescence and biomechanical assessments were utilized in a mouse model of ACS. The properties of siRNA-loaded liposomes were determined using laser particle size analyzer and electron microscopy.

Results

Proteomic analysis identified integrin α6 (ITGA6) as a significantly upregulated protein in the capsules of RCT patients with ACS compared to those without ACS. ITGA6 promoted cell proliferation, migration ability, and pro-fibrotic proteins expression, while the blockade of ITGA6 exhibited anti-fibrotic effect. The regulatory effect of ITGA6 was dependent on FAK/PI3K/Akt signaling pathway. Finally, liposome was prepared to carry si-ITGA6, and this si-ITGA6-loaded liposomes demonstrated a potent therapeutic effect in a mouse model of ACS. After si-ITGA6-loaded liposomes injection, the capsule thickness was decreased from 120.3 ± 14.3 μm to 73.3 ± 12.6 μm (p < 0.01), and the ROM also improved from 81.0 ± 9.0 to 112.2 ± 8.1 degrees (p < 0.01). These results indicated that si-ITGA6-loaded liposomes significantly ameliorated capsule fibrosis and joint mobility without indication of toxicity.

Conclusion

This research elucidated that ITGA6 was upregulated in the capsules of patients with ACS and is capable of significantly activating fibroblasts through the FAK/PI3K/Akt signaling pathway. By targeting ITGA6, si-ITGA6-loaded liposomes could effectively attenuate capsule fibrosis. In this study, we identified ITGA6 as a key regulator in ACS and demonstrated that targeting ITGA6 with siRNA-loaded liposomes effectively attenuated capsule fibrosis and improved joint mobility, offering a promising approach for targeted therapy of ACS.

Assessing the impact of triiodothyronine treatment on the lung microbiome of mice with pulmonary fibrosis

BACKGROUND

Idiopathic pulmonary fibrosis (IPF), an interstitial lung disease, is characterized by the exacerbation of progressive pulmonary fibrosis (PF). IPF primarily affects older individuals and can lead to respiratory failure. This study aimed to assess the effects of triiodothyronine (T3) treatment on the lung microbiome of mice with PF.

METHODS

Mice were perfused with bleomycin (BLM) to establish a PF model. Using a randomized design, 40 female specific pathogen-free (SPF) C57BL6/N mice were divided into four groups: saline, saline + T3, BLM, and BLM + T3. Histological morphology was assessed through Hematoxylin and Eosin staining as well as Masson's Trichrome staining. For the identification of lung bacteria, 16S rRNA gene sequencing was employed. An Enzyme-Linked Immunosorbent Assay was used to measure total T3 (TT3), free T3 (FT3, and reverse T3 (rT3) levels in the peripheral serum.

RESULTS

T3 treatment ameliorated BLM-induced lung fibrosis and structural damage. The microbiome experienced a decrease in the abundance of Proteobacteria, Bacteroides, and Actinomycetes and an increase in the abundance of Firmicutes when exposed to BLM; however, T3 treatment reversed this effect. The four groups showed no significant difference in alpha microbiome diversity (P > 0.05). Serum concentrations of TT3 and FT3 were positively correlated with microbiome abundance (P < 0.05). Administration of T3 enhanced the microbiota in PF without affecting the diversity and biological functions of the microbiome (P > 0.05).

CONCLUSION

The administration of T3 demonstrated a favorable impact on the lung microbiota of mice afflicted with PF, thereby partially substantiating the potential role of T3 as a therapeutic agent in the management of PF.

Negative causal exploration of systemic sclerosis: a Mendelian randomization analysis

Systemic sclerosis (SSc), also known as scleroderma, is an autoimmune-related connective tissue disease with a complex and unknown pathophysiological mechanism with genes association. Several articles have reported a high prevalence of thyroid disease in SSc patients, while one study suggested a potential contribution of appendicitis to the development of SSc. To investigate this causal association, we conducted Mendelian randomization (MR) analysis using instrumental variables (IVs) to assess exposure and outcome. In the MR study involving two cohorts, all analyses were conducted using the TwoSampleMR package in R (version 4.3.0). Single nucleotide polymorphisms (SNPs) meeting a statistically significant threshold of 5E-08 were included in the analysis. Multiple complementary approaches including MR-IVW, MR-Egger, weighted median, simple mode, and weighted mode were employed to estimated the relationship between the exposure and outcome. Leave-one-out analysis and scatter plots were utilized for further investigation. Based on the locus-wide significance level, all of the MR analysis consequences manifested no causal association between the risk of appendicitis with SSc (IVW OR 0.319, 95% CI 0.063-14.055, P = 0.966). Negative causal effects of autoimmune thyroiditis (AT) on SSc (IVW OR 0.131, 95% CI 0.816-1.362, P = 0.686), Graves' disease (GD) on SSc (IVW OR 0.097, 95% CI 0.837-1.222, P = 0.908), and hypothyroidism on SSc (IVW OR 1.136, 95% CI 0.977-1.321, P = 0.096) were derived. The reverse MR revealed no significant causal effect of SSc on thyroid disease. According to the sensitivity analysis, horizontal pleiotropy was unlikely to distort the causal estimates. The consequences indicated no significant association between AT, GD, and hypothyroidism with SSc. Similarly, there was no observed relationship with appendicitis.