Association between early immunophenotypic changes and therapeutic response of belimumab in patients with systemic lupus erythematosus.

Belimumab is a therapeutic medication that inhibits the B-cell-activating factor (BAFF) used for systemic lupus erythematosus (SLE); however, the response sometimes varies among individuals, even when patients are stratified based on general clinical characteristics. Therefore, we focused on immunological phenotypic changes with belimumab, investigated their association with subsequent clinical courses, and sought to identify relevant immunological indicators to stratify patients who would benefit from belimumab. We assessed changes in B and T cell phenotypes, as well as BAFF-related factors, such as levels of BAFF and a proliferation-inducing ligand, and expression of three BAFF receptors: BAFF receptor (BAFF-R), B-cell maturation antigen (BCMA), transmembrane activator and cyclophilin ligand interactor (TACI), in 19 patients with SLE who were treated with belimumab before and 3 months after treatment. First, to visualize patterns in complex and diverse data, we summarized B cell changes such as subsets and BAFF receptor expressions into two axes, the first and second principal components (PC1 and PC2), and characterized broad phenotypic changes by cluster analysis. Next, we evaluated whether the B cell changes represented by PC1 and PC2 were associated with other concurrent phenotypic changes, baseline factors, and treatment response at 6 months. We found that lower PC2, indicating increased BAFF-R expression and decreased percentage of naïve B cells, was associated with a subsequent therapeutic response at 6 months (odds ratio 5.3, 95% confidence interval 1.2-24, p = .031). Furthermore, higher percentages of effector memory CD3+CD4+ T cells at baseline were associated with lower PC2 and therapeutic response. Further analysis revealed that increased PC1, as reflected by increased BCMA and TACI expression and an increase in the percentage of class-switched memory B cells, was associated with both T and B cell activation. Although belimumab is a B-cell targeted therapy, it can also influence T-cell phenotypes. Thus, early B cell changes could be used to predict treatment response, and their changes could be predicted from baseline T cell phenotypes, indicating the importance of B and T cell interactions.

Post-staining Raman analysis of histological sections following decolorization.

Hematoxylin and eosin (HE) staining of tissue sections is a powerful tool for observing changes in the tissue structure and is used as the most fundamental and vital technique in histology. However, xenobiotics such as polymers and inorganic or organic materials have low dyeability, making it difficult to observe the distribution of materials across tissues. Raman spectroscopy is an advantageous technique for identifying materials in tissues using spectroscopic fingerprints by laser irradiation without staining. In this study, we developed a combined method for morphological observation and Raman spectral acquisition on the identical tissue slide by employing a decolorization step to remove eosin-induced fluorescence in HE-stained samples. Our method eliminated the fluorescence background and allowed the identical-field pathological observation, enabling simultaneous identification of biological responses and materials in tissues.

Risk of adrenal insufficiency in patients with polymyalgia rheumatica versus patients with rheumatoid arthritis: A cross-sectional study.

OBJECTIVE: To determine whether patients with polymyalgia rheumatica (PMR) are more susceptible to glucocorticoid-induced adrenal insufficiency, one of the barriers to glucocorticoid tapering strategies, compared to patients with rheumatoid arthritis (RA). METHODS: This cross-sectional study included PMR and RA patients who underwent adrenocorticotropic hormone (ACTH) tests to assess adrenal function. The eligibility criteria were as follows: previous use of prednisolone (PSL) ≥ 5 mg/day, use of PSL for six consecutive months before ACTH test, and current use of PSL at 5 mg/day or less. The association between disease type (PMR vs. RA) and insufficient adrenal response was assessed using logistic regression models. RESULTS: Twenty-six of 34 (76.5%) patients with PMR and 13 of 37 (35.1%) patients with RA had insufficient adrenal response. Compared to patients with RA, patients with PMR were more likely to have insufficient adrenal response, even after adjusting for age, sex, and PSL dose (adjusted odds ratio, 6.75; 95% confidence interval, 1.78-25.60). CONCLUSION: Patients with PMR have a higher risk of glucocorticoid-induced adrenal insufficiency than patients with RA. Assessing the adrenal function in patients with PMR will contribute to establishing a more appropriate glucocorticoid reduction strategy.

CG223, a novel BET inhibitor, exerts TGF-ß1-mediated antifibrotic effects in a murine model of bleomycin-induced pulmonary fibrosis.

Pulmonary fibrosis is a progressive disease with poor prognosis and limited therapeutic options. In this study, we evaluated the potential therapeutic effects of CG223, a novel inhibitor of bromodomain and extra-terminal motif (BET) proteins, on pulmonary fibrosis by focusing on the transforming growth factor-ß1 (TGF-ß1) pathway. In a murine model of bleomycin-induced pulmonary fibrosis, CG223 attenuated fibrosis while reducing the infiltration of inflammatory cells into the lungs. Fibroblasts expressing BRD4, a member of the BET protein family, were enriched in the tissue regions corresponding to bleomycin-induced fibrotic lesions. Additionally, pulmonary fibroblasts isolated from bleomycin-instilled mice showed a significantly increased association of BRD4 with the promoters of two pro-fibrotic genes linked to the entry into the TGF-ß1 autocrine/paracrine loop, thrombospondin 1 (Thbs1) and integrin ß3 (Itgb3), as well as with the promoter of a myofibroblast marker gene, actin alpha 2 (Acta2). Subsequent in vitro studies with murine primary lung fibroblasts showed that the mRNA induction of Thbs1, Itgb3, and Acta2 by TGF-ß1 can be inhibited by CG223 in a dose-dependent manner. Taken together, CG223-induced BRD4 inhibition suppressed lung fibrogenesis by affecting multiple genes, including those involved in the triggering of the TGF-ß1 autocrine/paracrine loop.

Exposure to particulate matter upregulates ACE2 and TMPRSS2 expression in the murine lung.

Coronavirus disease (COVID-19) is currently a serious global issue. Epidemiological studies have identified air pollutants, including particulate matter (PM), as a risk factor for COVID-19 infection and severity of illness, in addition to numerous factors such as pre-existing conditions, aging and smoking. However, the mechanisms by which air pollution is involved in the manifestation and/or progression of COVID-19 is still unknown. In this study, we used a mouse model exposed to crude PM, collected by the cyclone method, to evaluate the pulmonary expression of angiotensin-converting enzyme 2 (ACE2) and transmembrane protease serine type 2 (TMPRSS2), the two molecules required for the entry of severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2) into host cells. Multiplex immunohistochemical analysis revealed that exposure to PM increased the expression of these two molecules at the same site. Furthermore, image cytometry analysis revealed increased expression of these proteins, particularly, in the alveolar type 2 cells and macrophages, which are potential targets for SARS-CoV-2. Our findings provide an experimental evidence that exposure to PM may adversely affect the manifestation and progression of COVID-19, mediated by the impact of SARS-CoV-2 on the site of entry. The study results suggest that examining these effects might help to advance our understanding of COVID-19 and aid the development of appropriate social interventions.

Role of necroptosis of alveolar macrophages in acute lung inflammation of mice exposed to titanium dioxide nanoparticles.

Titanium dioxide (TiO2) nanoparticles are indispensable for daily life but induce acute inflammation, mainly via inhalation exposure. TiO2 nanoparticles can be phagocytosed by alveolar macrophages (AMs) in vivo and cause necroptosis of exposed cells in vitro. However, the relationship between localization of TiO2 nanoparticles in the lungs after exposure and their biological responses including cell death and inflammation remains unclear. This study was conducted to investigate the intra/extracellular localization of TiO2 nanoparticles in murine lungs at 24 h after intratracheal exposure to rutile TiO2 nanoparticles and subsequent local biological reactions, specifically necroptosis of AMs and lung inflammation. We found that TiO2 exposure induced leukocyte migration into the alveolar region and increased the secretion of C-C motif ligand (CCL) 3 in the bronchoalveolar lavage (BAL) fluid. A combination of Raman spectroscopy and staining of cell and tissue samples confirmed that AMs phagocytose TiO2. AMs that phagocytosed TiO2 nanoparticles showed necroptosis, characterized by the expression of phosphorylated mixed lineage kinase domain-like protein and translocation of high mobility group box-1 from the cell nucleus to the cytoplasm. In primary cultured AMs, TiO2 also induced necroptosis and increased the secretion of CCL3. Necroptosis inhibitors suppressed the increase in CCL3 secretion in both the BAL fluid and culture supernatant of AMs and suppressed the increase in leukocytes in the BAL fluid. These data suggest that necroptosis of AMs that phagocytose TiO2 nanoparticles is involved as part of the mechanism by which TiO2 induces acute lung inflammation.

Association between preexisting lung involvements and the risk of diffuse alveolar hemorrhage in patients with microscopic polyangiitis: A multi-center retrospective cohort study.

Objectives: To identify the factors associated with the risk of diffuse alveolar hemorrhage (DAH) in patients with microscopic polyangiitis (MPA), focusing on other preexisting lung involvements such as interstitial lung disease (ILD) and airway disease.Methods: In this retrospective cohort study, we analyzed consecutive patients with myeloperoxidase-antineutrophil cytoplasmic antibody-positive MPA who had undergone chest computed tomography (CT) before starting treatment between 2006 and 2016. Patients who already had DAH at initial CT imaging were excluded. CT images were evaluated for the presence of ILD and airway disease. The association between preexisting lung involvements and the development of DAH was assessed using logistic regression models adjusted for various clinical characteristics.Results: We identified 113 patients (median age 72 years; median follow-up duration 39 months), and 27 (24%) of them developed DAH during the follow-up. Airway disease was identified in 41 (36%) patients and was independently associated with the development of DAH (adjusted odds ratio 6.86, 95% confidence interval 1.85-25.4). However, ILD identified in 45 (40%) patients was not associated with DAH.Conclusion: Our findings suggest that DAH in MPA occurs frequently in patients with airway disease. Attention to preexisting airway disease may help predict the development of DAH.

Utility of Coagulation Markers for the Prediction of Rapidly Progressive Interstitial Lung Disease in Patients with Dermatomyositis.

We aimed to evaluate the utility of coagulation markers for the prediction of rapidly progressive interstitial lung disease (RP-ILD) in patients with dermatomyositis (DM). In this retrospective study, 29 patients with DM-associated ILD were analyzed. The number of patients with RP-ILD was 15 (52%). The baseline clinical and demographic data and laboratory markers were analyzed to identify predictive factors for RP-ILD.The univariate logistic regression analysis demonstrated that in addition to well-known laboratory markers, such as serum ferritin, KL-6, and lymphocyte counts, a prolonged activated partial thromboplastin time (aPTT) ratio at the time of DM-associated ILD diagnosis was useful for predicting RP-ILD. Moreover, the logistic regression model and receiver operating characteristic curve analysis showed that combinations of the aPTT ratio and well-known laboratory markers were significantly effective in predicting RP-ILD. This study suggested that an association between RP-ILD and the coagulation system exists.

Upregulation of sphingosine-1-phosphate receptor 3 on fibroblast-like synoviocytes is associated with the development of collagen-induced arthritis via increased interleukin-6 production.

BACKGROUND: Sphingosine-1-phosphate receptor 3 (S1P3) is one of five receptors for sphingosine-1-phosphate (S1P). S1P/S1P3 signaling is involved in numerous physiological and pathological processes including bone metabolism, sepsis, cancer, and immunity. In rheumatoid arthritis (RA), fibroblast-like synoviocytes (FLSs) are activated by several factors and promote abundant proinflammatory cytokine production and bone destruction. The aim of this study was to investigate whether S1P3 is associated with the development of autoimmune arthritis and the pathogenic function of FLSs. METHODS: Wild-type (WT) and S1P3 knockout (S1P3-KO) collagen-induced arthritis (CIA) mice were evaluated with respect to clinical and histological disease severity, along with the levels of anti-collagen antibodies and expression of tumor necrosis factor-α (TNFα) and interleukin-6 (IL-6). S1P3 expression in the synovium was analyzed by real-time reverse-transcription polymerase chain reaction (RT-PCR) and immunofluorescence staining. FLSs isolated from CIA mice were activated with TNFα and S1P3 expression was analyzed by real-time RT-PCR. The role of S1P/S1P3 signaling in activated and non-activated FLSs was investigated by measuring cell proliferation and cyto/chemokine production by real-time RT-PCR and/or enzyme-linked immunosorbent assay. RESULTS: Clinical and histological scores, and synovial IL-6 expression were significantly lower in S1P3-KO mice with CIA than in WT mice. Arthritic synovia had higher S1P3 expression than intact synovia and FLSs in arthritic joints expressed S1P3 in vivo. Primary cultured FLSs produced IL-6 in a time-dependent manner in response to S1P stimulation and exhibited higher levels of S1P3 expression after activation with TNFα. S1P3-induced production of IL-6 and MMP-3 was increased in FLSs pre-activated with TNFα. CONCLUSION: In this study, we demonstrated that S1P3 expression is associated with the development of autoimmune arthritis via inflammation-induced increases in S1P/S1P3 signaling that increase production of IL-6 in FLSs. Inhibition of S1P/S1P3 signaling could open the door to the development of new therapies for RA.