Autophagy promotes aortic adventitial fibrosis via the IL-6/Jak1 signaling pathway in Takayasu's arteritis

Pro-fibrotic effect of the susceptible gene PCSK5 in vascular fibrosis of Takayasu arteritis via TGF-β and SMAD3 signaling pathway activation

BACKGROUND

Vascular fibrosis directly causes vascular thickening in Takayasu arteritis (TAK), in which sustained transforming growth factor beta (TGF-β) activation is critical. Understanding TGF-β activation regulation and blocking it might yield a therapeutic effect in TAK. Proprotein convertase subtilisin/kexin type 5 (PCSK5) rs6560480 (T/C) is associated with TAK development. In this study, we assessed the association between the PCSK5 rs6560480 genotype and PCSK5 expression in TAK and explored its molecular role in TGF-β activation and vascular fibrosis development.

METHODS

In TAK patients, PCSK5 and TGF-β expression in plasma and aortic tissue was examined by ELISA and immunohistochemical staining, and PCSK5 rs6560480 was genotyped. The correlation between PCSK5 and extracellular matrix (ECM) expression was examined by Western blotting (WB) and immunohistochemistry staining. Detection by co-immunoprecipitation was performed to detect the interaction between PCSK5 and TGF-β in adventitial fibroblasts (AAFs). Downstream signaling pathways were detected by WB and validated with appropriate inhibitors. Potential immunosuppressive agents to inhibit the effects of PCSK5 were explored in cell culture and TAK patients.

RESULTS

Patients with PCSK5 rs6560480 TT patients had significantly higher PCSK5 levels and more thickened vascular lesions than patients with PCSK5 rs6560480 CT. PCSK5 expression was significantly increased in alpha smooth muscle actin (α-SMA)-positive myofibroblasts in TAK vascular lesions. Overexpressing PCSK5 facilitated TGF-β and downstream SMAD2/3 activation and ECM expression in AAFs and aorta in in-vitro culture. The mechanistic study supported that PCSK5 activated precursor TGF-β (pro-TGF-β) to the mature form by binding the pro-TGF-β cleavage site. Leflunomide inhibited PCSK5 and pro-TGF-β binding, decreasing TGF-β activation and ECM expression, which was also partially validated in leflunomide-treated patients.

CONCLUSION

The findings revealed a novel pro-fibrotic mechanism of PCSK5 in TAK vascular fibrosis via TGF-β and downstream SMAD2/3 pathway activation. Leflunomide might be anti-fibrotic by disrupting PCSK5 and pro-TGF-β binding, presenting a new TAK treatment approach.

A Glimpse into Humoral Response and Related Therapeutic Approaches of Takayasu's Arteritis

Takayasu's arteritis (TAK) manifests as an insidiously progressive and debilitating form of granulomatous inflammation including the aorta and its major branches. The precise etiology of TAK remains elusive, with current understanding suggesting an autoimmune origin primarily driven by T cells. Notably, a growing body of evidence bears testimony to the widespread effects of B cells on disease pathogenesis and progression. Distinct alterations in peripheral B cell subsets have been described in individuals with TAK. Advancements in technology have facilitated the identification of novel autoantibodies in TAK. Moreover, emerging data suggest that dysregulated signaling cascades downstream of B cell receptor families, including interactions with innate pattern recognition receptors such as toll-like receptors, as well as co-stimulatory molecules like CD40, CD80 and CD86, may result in the selection and proliferation of autoreactive B cell clones in TAK. Additionally, ectopic lymphoid neogenesis within the aortic wall of TAK patients exhibits functional characteristics. In recent decades, therapeutic interventions targeting B cells, notably utilizing the anti-CD20 monoclonal antibody rituximab, have demonstrated efficacy in TAK. Despite the importance of the humoral immune response, a systematic understanding of how autoreactive B cells contribute to the pathogenic process is still lacking. This review provides a comprehensive overview of the biological significance of B cell-mediated autoimmunity in TAK pathogenesis, as well as insights into therapeutic strategies targeting the humoral response. Furthermore, it examines the roles of T-helper and T follicular helper cells in humoral immunity and their potential contributions to disease mechanisms. We believe that further identification of the pathogenic role of autoimmune B cells and the underlying regulation system will lead to deeper personalized management of TAK patients. We believe that further elucidation of the pathogenic role of autoimmune B cells and the underlying regulatory mechanisms holds promise for the development of personalized approaches to managing TAK patients.

An emerging view on vascular fibrosis molecular mediators and relevant disorders: from bench to bed

Vascular fibrosis is a widespread pathologic condition that arises during vascular remodeling in cardiovascular dysfunctions. According to previous studies, vascular fibrosis is characterized by endothelial matrix deposition and vascular wall thickening. The RAAS and TGF-β/Smad signaling pathways have been frequently highlighted. It is, however, far from explicit in terms of understanding the cause and progression of vascular fibrosis. In this review, we collected and categorized a large number of molecules which influence the fibrosing process, in order to acquire a better understanding of vascular fibrosis, particularly of pathologic dysfunction. Furthermore, several mediators that prevent vascular fibrosis are discussed in depth in this review, with the aim that this will contribute to the future prevention and treatment of related conditions.

A multicentre, large-scale, observational study of tocilizumab in patients with Takayasu arteritis in Japan: The ACTEMRA® (ACT)-Bridge study

OBJECTIVES

We evaluated the real-world tolerability and effectiveness of tocilizumab in Japanese patients with Takayasu arteritis (TAK).

METHODS

Patients with TAK who had not received tocilizumab in the previous 6 months were enrolled in ACTEMRA® (ACT)-Bridge, a phase 4, observational study, from 66 Japanese institutions (enrolment period, September 2017 to September 2020) and received weekly subcutaneous tocilizumab 162 mg (observation period, 52 weeks).

RESULTS

Among 120 patients included (mean age, 38.4 years; mean disease duration, 7.7 years; treated for relapse, 50.8%; previous immunosuppressant use, 57.5%; glucocorticoid use at baseline, 97.5%), 49 (40.8%) reported adverse events. The most common adverse event of special interest was serious infection (7.5%). Relapse was observed in 24 (20.0%) patients (0.8%, 2.5%, and 16.7% reporting ≥3, 2, and 1 relapses, respectively). The reasons for diagnosing relapse included chest and back pain (45.8%), neck pain (25.0%), fatigue (16.7%), fever and headache (12.5% each), abnormal imaging findings (50.0%), and elevated inflammatory markers (16.7%). At the last observation, 83.0% of relapse-free patients recorded a concomitant glucocorticoid dose (prednisolone equivalent) <10 mg/day.

CONCLUSIONS

This study demonstrated the effectiveness of tocilizumab in patients with TAK, with no new safety concerns. Tocilizumab plus glucocorticoids may be considered a treatment option for TAK.

High level of serum complement 3 is a risk factor for vascular stenosis progression in TA patients receiving tocilizumab: a prospective observational study

BACKGROUND

The IL-6R antibody tocilizumab has been proven effective in treating Takayasu arteritis (TA). However, some patients show silent vascular stenosis progression (VSP) despite treatment with tocilizumab. The aim of the study was to explore the related risk factors of VSP in patients treated with tocilizumab.

METHODS

Patients receiving tocilizumab were enrolled from the prospective living ongoing East China Takayasu Arteritis cohort. Their medical information was uniformly recorded with a homogenized evaluation method. Magnetic resonant angiography or computed tomographic angiography was employed to monitor VSP during the follow-up period, and Cox regression analysis was performed to explore the related risk factors.

RESULTS

Thirty-eight patients were enrolled, among whom 18 (47.4%) experienced VSP, and seven and three patients experienced new and worsened vascular ischemic symptoms and events (VISE) during follow-up, respectively. The median period for VSP occurrence was 6.9 months during follow-up. Patients with VSP showed higher levels of baseline complement 3 (C3) than those in the patients without VSP. Multivariate Cox regression analysis revealed baseline C3 level (hazard ratio [HR] = 7.05, 95% confidence interval: 1.50-33.07, p = 0.013) was independently associated with VSP, with a cut-off value of 1.22 g/L.

CONCLUSIONS

47.4% of TA patients treated with tocilizumab would suffer VSP. A high C3 level is a risk factor for VSP in TA patients receiving tocilizumab, which may facilitate the option of tocilizumab in the future.

Arterial wall fibrosis in Takayasu arteritis and its potential for therapeutic modulation

Arterial wall damage in Takayasu arteritis (TAK) can progress despite immunosuppressive therapy. Vascular fibrosis is more prominent in TAK than in giant cell arteritis (GCA). The inflamed arterial wall in TAK is infiltrated by M1 macrophages [which secrete interleukin-6 (IL-6)], which transition to M2 macrophages once the inflammation settles. M2 macrophages secrete transforming growth factor beta (TGF-β) and glycoprotein non-metastatic melanoma protein B (GPNMB), both of which can activate fibroblasts in the arterial wall adventitia. Mast cells in the arterial wall of TAK also activate resting adventitial fibroblasts. Th17 lymphocytes play a role in both TAK and GCA. Sub-populations of Th17 lymphocytes, Th17.1 lymphocytes [which secrete interferon gamma (IFN-γ) in addition to interleukin-17 (IL-17)] and programmed cell death 1 (PD1)-expressing Th17 (which secrete TGF-β), have been described in TAK but not in GCA. IL-6 and IL-17 also drive fibroblast activation in the arterial wall. The Th17 and Th1 lymphocytes in TAK demonstrate an activation of mammalian target organ of rapamycin 1 (mTORC1) driven by Notch-1 upregulation. A recent study reported that the enhanced liver fibrosis score (derived from serum hyaluronic acid, tissue inhibitor of metalloproteinase 1, and pro-collagen III amino-terminal pro-peptide) had a moderate-to-strong correlation with clinically assessed and angiographically assessed vascular damage. In vitro experiments suggest the potential to target arterial wall fibrosis in TAK with leflunomide, tofacitinib, baricitinib, or mTORC1 inhibitors. Since arterial wall inflammation is followed by fibrosis, a strategy of combining immunosuppressive agents with drugs that have an antifibrotic effect merits exploration in future clinical trials of TAK.

The effectiveness of tocilizumab and its comparison with tumor necrosis factor alpha inhibitors for Takayasu Arteritis: A systematic review and meta-analysis

Takayasu arteritis (TAK) refractory to conventional disease-modifying anti-rheumatic drugs (DMARDs) is commonly treated with biologic DMARDs such as tocilizumab or tumor necrosis factor-alpha inhibitors (TNFi). The 2021 American College of Rheumatology (ACR) recommendations preferred TNFi to tocilizumab. Therefore, we conducted a systematic review with meta-analysis to assess the evidence base for tocilizumab in TAK by updating a previous systematic review on DMARDs in TAK through searches on MEDLINE, Pubmed Central, Scopus, major international Rheumatology conference abstracts, and clinical trial databases from January 2021 to November 2022. Thirty-five studies involving 1082 TAK [one randomized controlled trial (RCT), eleven controlled and twenty-one uncontrolled studies, most of moderate to high quality] had evaluated tocilizumab in TAK. The RCT of tocilizumab versus placebo failed to meet its primary end-point of superiority of tocilizumab on an intention-to-treat analysis (hazard ratio 0.41, 95%CI 0.15-1.10) but successfully met the secondary end-point of superiority on per-protocol analysis (hazard ratio 0.34, 95%CI 0.11-1.00). A meta-analysis of six studies identified similar rates of clinical remission [risk ratio (RR) tocilizumab vs TNFi 1.03, 95%CI 0.91-1.17)], angiographic stabilization (RR 1.00, 95%CI 0.72-1.40) or adverse events (RR 0.84, 95%CI 0.54-1.31) with tocilizumab or TNFi. A meta-analysis of three studies identified superior clinical response (RR 1.55, 95%CI 1.15-2.10) and adverse effect profile (RR 0.45, 95%CI 0.25-0.80) with tocilizumab than cyclophosphamide. Pooled data from uncontrolled studies identified clinical response in 85%(95%CI 79-91%) and angiographic stabilization in 82% (95%CI 68-94%). Our study suggests similar evidence for treating TAK with tocilizumab or TNFi, contrary to the ACR 2021 recommendations.

A novel molecular mechanism of vascular fibrosis in Takayasu arteritis: macrophage-derived GPNMB promoting adventitial fibroblast extracellular matrix production in the aorta

Takayasu arteritis (TAK) is a chronic large vessel disease characterized by aortic fibrotic thickening, which was mainly mediated by activation of aorta adventitial fibroblasts (AAFs). Our previous genetic study demonstrated that TAK-associated locus IL6 rs2069837 regulated glycoprotein non-metastatic melanoma protein B (GPNMB) expression. Thus, this study aimed to investigate the pathogenic role of GPNMB in TAK. Through pathological staining, we find that GPNMB was mainly expressed in vascular adventitia and positively correlated with adventitial extracellular matrix (ECM) expression in TAK vascular lesion. Specifically, GPNMB was increased in adventitial CD68⁺ macrophages, which were closely located with CD90⁺ adventitial fibroblasts. In in-vitro cell culture, THP-1-derived macrophages with GPNMB overexpression promoted ECM expression in AAFs. This effect was also confirmed in aortic tissue or AAFs culture with GPNMB overexpression or active GPNMB protein stimulation. Mechanistically, Co-IP assay and siRNA or inhibitor intervention demonstrated that integrin αVβ1 receptor mediated GPNMB effect on AAFs, which also activated downstream Akt and Erk pathway in AAFs. Furthermore, we showed that leflunomide treatment inhibited GPNMB-mediated fibrosis in AAFs, as well as GPNMB expression in macrophages, which were also partially validated in leflunomide-treated patients. Taken together, these data indicated that macrophage-derived GPNMB promotes AAFs ECM expression via the integrin αVβ1 receptor and Akt/Erk signaling pathway and leflunomide might play an anti-fibrotic role in TAK by interfering with the macrophage-derived GPNMB/AAFs axis. This study provides evidence that targeting GPNMB is a potential therapeutic strategy for treating vascular fibrosis in TAK.

Risk factors of aortic regurgitation progression in Chinese patients with Takayasu's arteritis: a prospective cohort study

OBJECTIVE

To elucidate the 3-year follow-up outcomes and risk factors associated with aortic regurgitation progression in Takayasu's arteritis (TAK).

METHODS

This study was a prospective cohort study conducted among 77 patients with TAK at Zhongshan Hospital, Fudan University, China. All the participants were followed up and assessed with echocardiography for 3 years, and the baseline characteristics and dynamic changes in the aortic valve were recorded and investigated. A multivariable Cox model was used to explore the risk factors for aortic regurgitation progression.

RESULTS

The median onset age was 36.9 (26.0-44.4) years, and 57 patients (74.0%) were females. Fifty patients (64.9%) complained of aortic regurgitation, which was the most common valvular lesion at baseline. During the 3-year follow-up period, the progression of aortic regurgitation was observed in 29 (37.7%) patients with TAK. The progression group had higher baseline erythrocyte sedimentation rate (ESR; p = 0.013) and interleukin (IL)-6 (p = 0.029) levels and lower early treatment remission rates (p = 0.024). According to the Cox model, the elevated baseline IL-6 level [>13 pg/ml, hazard ratio (HR) = 2.4, 95% confidence interval (CI) = 1.0-5.8, p = 0.042] and absence of early treatment remission (HR = 3.3, 95% CI = 1.3-8.2, p = 0.010) were the independent risk factors for aortic regurgitation deterioration.

CONCLUSION

About one-third of patients with TAK experienced aortic regurgitation progression within 3 years from first admission. Elevated IL-6 levels at baseline and absence of early treatment remission were the two important risk factors for subsequent aortic regurgitation progression.

The Role of IL-6 in Fibrotic Diseases: Molecular and Cellular Mechanisms

Fibrosis is a detrimental outcome of most chronic inflammatory disorders and is defined by the buildup of excess extracellular matrix (ECM) components, which eventually leads to organ failure and death. Interleukin 6 (IL-6) is promptly produced by immune cells in response to tissue injuries and has a wide range of effects on cellular processes such as acute responses, hematopoiesis, and immune reactions. Furthermore, high levels of IL-6 have been found in a variety of chronic inflammatory disorders characterized by fibrosis, and this factor plays a significant role in fibrosis in various organs via Janus kinase/signal transducer and activator of transcription 3 (JAK/STAT3) activation. Here, we review what is known about the role of IL-6 in fibrosis and why targeting IL-6 for fibrotic disease treatment makes sense.

Caveolin-1 Alleviates Crohn's Disease-induced Intestinal Fibrosis by Inhibiting Fibroblasts Autophagy Through Modulating Sequestosome 1

BACKGROUND

Intestinal fibrosis is a common complication of Crohn's disease (CD) and is characterized by the excessive accumulation of extracellular matrix produced by activated myofibroblasts. Caveolin-1 (CAV1) inhibits fibrosis. However, limited data show that CAV1 affects intestinal fibrosis.

METHODS

Human CD tissue samples were gained from patients with CD who underwent surgical resection of the intestine and were defined as stenotic or nonstenotic areas. A dextran sodium sulfate-induced mouse model of intestinal fibrosis was established. For in vitro experiments, we purchased CCD-18Co intestinal fibrosis cells and isolated and cultured human primary colonic fibroblasts. These fibroblasts were activated by transforming growth factor β administration for 48 hours. In the functional experiments, a specific small interfering RNA or overexpression plasmid was transfected into fibroblasts. The messenger RNA levels of fibrosis markers, such as α-smooth muscle actin, fibronectin, connective tissue growth factor, and collagen I1α, were determined using quantitative polymerase chain reaction. Western blot analysis was applied to detect the expression of CAV1, SQSTM1/p62 (sequestosome 1), and other fibrosis markers.

RESULTS

In human CD samples and the dextran sodium sulfate-induced mouse model of intestinal fibrosis, we observed a downregulation of CAV1 in fibrosis-activated areas. Mechanistically, CAV1 knockdown in both human primary colonic fibroblasts and CCD-18Co cells promoted fibroblast activation, while CAV1 overexpression inhibited fibroblast activation in vitro. We found that SQSTM1/p62 positively correlated with CAV1 expression levels in patients with CD and that it was indirectly modulated by CAV1 expression. Rescue experiments showed that CAV1 decreased primary human intestinal fibroblast activation by inhibiting fibroblast autophagy through the modulation of SQSTM1/p62.

CONCLUSIONS

Our data demonstrate that CAV1 deficiency induces fibroblast activation by indirectly regulating SQSTM1/p62 to promote fibroblast autophagy. CAV1 or SQSTM1/p62 may be potential therapeutic targets for intestinal fibrosis.

Augmented PFKFB3-mediated glycolysis by interferon-γ promotes inflammatory M1 polarization through the JAK2/STAT1 pathway in local vascular inflammation in Takayasu arteritis

BACKGROUND

Takayasu arteritis (TAK) is characterized by pro-inflammatory M1 macrophage infiltration and increased interferon (IFN)-γ expression in vascular lesions. IFN-γ is a key cytokine involved in M1 polarization. Macrophage polarization is accompanied by metabolic changes. However, the metabolic regulation mechanism of IFN-γ in M1 macrophage polarization in TAK remains unclear.

METHODS

Immunohistochemistry and immunofluorescence were employed to observe the expression of IFN-γ, PFKFB3 (6-phosphofructo-2-kinase/fructose-2,6-biphosphatase 3, the rate-limiting enzyme in glycolysis), and macrophage surface markers in the vascular tissue. Monocyte-derived macrophages from patients with TAK were cultured to examine the role of PFKFB3 in IFN-γ-induced M1 macrophage polarization. Seahorse analysis was used to detect the alterations in glucose metabolism during this process. Quantitative reverse transcription PCR, flow cytometry, and western blot were used to confirm the phenotypes of macrophages and related signaling pathways.

RESULTS

In the vascular adventitia of patients with TAK, an increase in PFKFB3 accompanied by IFN-γ expression was observed in M1 macrophages. In vitro, IFN-γ successfully induced macrophage differentiation into the M1 phenotype, which was manifested as an increase in CD80 and HLA-DR markers and the pro-inflammatory cytokines IL-6 and TNF-α. During this process, PFKFB3 expression and glycolysis levels were significantly increased. However, glycolysis and M1 polarization induced by IFN-γ were suppressed by a PFKFB3 inhibitor. In addition, JAK2/STAT1 phosphorylation was also enhanced in macrophages stimulated by IFN-γ. The effects of IFN-γ on macrophages, including the expression of PFKFB3, glycolysis, and M1 polarization, were also inhibited by the JAK inhibitor tofacitinib or STAT1 inhibitor fludarabine.

CONCLUSION

PFKFB3-mediated glycolysis promotes IFN-γ-induced M1 polarization through the JAK2/STAT1 signaling pathway, indicating that PFKFB3 plays an important role in M1 polarization mediated by IFN-γ; thus, PFKFB3 is a potential intervention target in TAK.

Enhanced Liver Fibrosis Score as a Biomarker for Vascular Damage Assessment in Patients with Takayasu Arteritis-A Pilot Study

Takayasu Arteritis (TA) is characterized by granulomatous panarteritis, vessel wall fibrosis, and irreversible vascular impairment. The aim of this study is to explore the usefulness of the Enhanced Liver Fibrosis score (ELF), procollagen-III aminoterminal propeptide (PIIINP), tissue inhibitor of matrix metalloproteinase-1 (TIMP-1), and hyaluronic acid (HA) in assessing vascular damage in TA patients. ELF, PIIINP, TIMP-1, and HA were measured in 24 TA patients, and the results were correlated with the clinical damage indexes (VDI and TADS), an imaging damage score (CARDS), and disease activity scores (NIH and ITAS2010). A mean ELF score 8.42 (±1.12) and values higher than 7.7 (cut-off for liver fibrosis) in 21/24 (87.5%) of patients were detected. The VDI and TADS correlated significantly to ELF (p < 0.01). Additionally, a strong association across ELF and CARDS (p < 0.0001), PIIINP and CARDS (p < 0.001), and HA and CARDS (p < 0.001) was observed. No correlations of the tested biomarkers with inflammatory parameters, NIH, and ITAS2010 scores were found. To our knowledge, this is the first study that suggests the association of the serum biomarkers PIIINP, HA, and ELF score with damage but not with disease activity in TA patients. The ELF score and PIIINP may be useful biomarkers reflecting an ongoing fibrotic process and quantifying vascular damage.

A systematic review of clinical and preclinical evidences for Janus kinase inhibitors in large vessel vasculitis

Corticosteroid-sparing disease-modifying anti-rheumatic drugs are an area of active exploration in large vessel vasculitis (LVV), i.e., Takayasu arteritis (TAK) and Giant Cell Arteritis (GCA). The role of Janus kinase (JAK) inhibitors has been recently identified in different inflammatory rheumatic diseases. We conducted a systematic review of the use of JAK inhibitors in LVV across MEDLINE, Scopus, Web of Science, EMBASE, PubMed Central, Cochrane database of controlled trials, clinicaltrials.gov, and major recent international conferences. We identified four cohort studies and ten case reports. The JAK inhibitors used in these studies were tofacitinib, baricitinib, and ruxolitinib. A cohort study in TAK compared 27 patients treated with tofacitinib with 26 others treated with methotrexate, with better clinical outcomes with tofacitinib but similar angiographic stabilization, relapses, corticosteroid-sparing effect, and adverse events in both groups. Most of the other studies favored clinical responses with JAK inhibitors in LVV but with a paucity of data on other outcomes. Most of the included studies were of moderate quality. Evidence from pre-clinical models of LVV as well as limited in vivo data in patients with TAK appears to suggest that JAK inhibition reduces adventitial fibrosis, intimal proliferation, and inflammatory T lymphocyte infiltration in the media as well as reduces resident memory T cells in the vascular wall (which are otherwise resistant to corticosteroids). Ongoing clinical trials of tofacitinib, baricitinib, and upadacitinib in LVV shall help to further clarify the potential promise of JAK inhibitors for LVV (PROSPERO registration number CRD42021273359). KEY POINTS : •Tofacitinib appeared to associate with better clinical outcomes than methotrexate in TAK. •JAKinibs reduce adventitial fibrosis, intimal proliferation, and inflammatory vascular infiltrate in pre-clinical models of LVV. •Tofacitinib downregulates resident memory vascular T lymphocytes in pre-clinical models of LVV.

FABP3 overexpression promotes vascular fibrosis in Takayasu's arteritis via enhancing fatty acid oxidation in aorta adventitial fibroblasts

OBJECTIVE

To identify the role of fatty acid-binding protein-3 (FABP3) in vascular fibrosis in Takayasu's arteritis (TAK) and to explore the underlying molecular mechanism.

METHODS

The expression of FABP3 and extracellular matrix proteins (ECMs) were detected in aorta tissues from TAK patients (n = 12) and healthy controls (n = 8) by immunohistochemistry. The concentration of serum proteins was determined by ELISA. CCK8 and Ki67 staining were used to measure aorta adventitial fibroblasts (AAFs) proliferation. Widely-targeted lipidomic profiling was used to screen for associated metabolic pathways. Changes in ECMs and fatty acid oxidation (FAO) related enzymes were determined by RT-qPCR and Western blot. The interactions between FABP3 and these enzymes were explored with Co-immunoprecipitation (Co-IP) assay.

RESULTS

The expression of FABP3 was increased in the thickened adventitia of TAK patients, and was positively correlated with the serum expression of ECMs. FABP3 knockdown inhibited AAF proliferation and ECMs production, whereas FABP3 overexpression enhanced these processes. Further analysis revealed that FABP3 upregulation promoted carnitine palmitoyltransferase 1A (CPT1A) and carnitine/acylcarnitine carrier protein (CACT) expressions, two key enzymes in FAO, as well as ATP levels. FABP3 and CACT were co-localized in the adventitia and bound to each other in AAFs. Etomoxir reversed the enhanced FAO, ATP production, AAF proliferation, and ECM production mediated by FABP3 upregulation. Treatment with 60 g/day curcumin granules for three months reduced the level of serum FABP3. Curcumin also inhibited vascular fibrosis by reducing FABP3-enhanced FAO in AAFs.

CONCLUSION

Elevated FABP3 expression accelerated vascular fibrosis in TAK, which was likely mediated by promoting FAO in AAFs.

Application progress of multiple imaging modalities in Takayasu arteritis

Takayasu arteritis (TA) is a chronic, idiopathic, granulomatous large vessel vasculitis of unknown etiology. The clinical manifestations of TA are incredibly variable, mainly depending on the location of the lesions. In the light of its insidious progress and the diversity of clinical manifestations, a substantial proportion of patients might experience a considerable delay in diagnosis, which leads to irreversible malignant complications, highlighting the importance of early diagnosis. There has been accumulating evidence that early identification of disease is pivotal to initiate timely therapy and ameliorate the prognosis. Therefore, this review discusses and summarizes the latest evidence on the application progress of multiple imaging modalities.

Inhibition of p53/miR-34a/SIRT1 axis ameliorates podocyte injury in diabetic nephropathy

Podocyte injury is associated with albuminuria and the progression of diabetic nephropathy (DN). MiR-34a, a p53-regulated miRNA, directly targets SIRT1 and contributed to DN progression. MiR-34a represses SIRT1 to activate p53 and establish a positive feedback loop. However, whether p53/miR-34a/SIRT1 signaling is activated in podocytes and contributes to DN pathogenesis remains elusive. In this study, we observed that serum miR-34a level was positively correlated with podocyte injury in DN patients. The expression of acetylated p53 and miR-34a was upregulated, SIRT1was downregulated in glomeruli from patients with DN and STZ induced diabetic mice, as well as in human podocytes treated with advanced glycation end (AGE). MiR-34a antagonism in vitro and vivo in STZ induced diabetic mice developed alleviated glomerulus injury as reflected by attenuated albuminuria, reduced podocyte loss and restored autophagic flux. In human podocyte, inhibition of AGE formation by pyridoxamine prevented miR-34a dependent repression of SIRT1, p53 acetylation and activate podocyte autophagy in a dose-dependent manner. MiR-34a overexpression increases acetylation of p53 by translational repression of SIRT1. SIRT1 overexpression also impacts AGE induced apoptosis through deacetylating p53, whereas silencing of SIRT1 by EX527 attenuated the cytoprotective functions of miR-34a knockdown. Moreover, blockade of p53 acetylation significantly rescued miR-34a-induced apoptosis through SIRT1 restoration. Collectively, we demonstrate that by activation of p53, AGE induced the transcription of miR-34a, miR-34a in turn repressed SIRT1 to activate p53, resulting in a positive-feedback loop and contributing to podocyte injury. Targeting modulation of p53/miR-34a/SIRT1 feedback by miR-34a knockdown or overexpression of SIRT1 could rescue podocyte injury during DN.

Targeting the TGF-β signaling pathway for fibrosis therapy: a patent review (2015-2020)

INTRODUCTION

Fibrosis is a serious disease that occurs in many organs, such as kidney, liver and lung. The deterioration of these organs ultimately leads to death. Due to the complex mechanisms of fibrosis, research and development of antifibrotic drugs is difficult. One solution is to focus on core pathways, one of which is the TGF-β signaling pathway. In virtually every type of fibrosis, TGF-β signaling is recognized as a critical pathway.

AREA COVERED

This review discusses patents on active molecules related to the TGF-β signaling. Molecules targeting components related to the activation of TGF-β are introduced. Several strategies preventing signal propagation from active TGF-β to downstream targets are also introduced, including TGF-β antibodies, TGF-β ligand traps, and inhibitors of TGF-β receptor kinases. Finally, molecules affecting downstream targets in both canonical and noncanonical TGF-β signaling pathways are described.

EXPERT OPINION

Since the approval of pirfenidone, targeting TGF-β signaling has been anticipated as an effective therapy for fibrosis. The potential of this therapy has been further supported by emerging patents on the TGF-β signaling. This pathway can be entirely inhibited, from the activation of TGF-β to downstream signaling. Inhibiting TGF-β signaling is expected to provide more effective treatments for fibrosis.

Induced Autophagy of Macrophages and the Regulation of Inflammatory Effects by Perovskite Nanomaterial LaNiO3

Perovskite nanomaterials (NMs) possess excellent physicochemical properties and have promising applications in light-emitting diodes (LEDs), lasers, photodetectors, and artificial synapse electronics. Potential exposure to these NMs happens in the manufacture and application of the perovskite-based products, however, the biological safety of these NMs is still unknown. Here, we used the LaNiO₃ NM (LNO), a typical kind of perovskite nanostructures to study the interaction with macrophages (J774A.1) and to explore its biological effects at the cellular level. Firstly, we characterized the properties of LNO including the size, shape, and crystal structure using Transmission electronic microscope (TEM), Dynamic lighting scattering (DLS), and X-ray diffraction (XRD). Secondly, to gain a better understanding of the biological effect, we evaluated the effect of LNO on cell viability and found that LNO induced cell autophagy at a concentration of 5 μg/ml and influenced the inflammatory response based on RT-PCR result. Finally, we demonstrated the mechanism that LNO causes cell autophagy and immune response is probably due to the metal ions released from LNO in acidic lysosomes, which triggered ROS and increased lysosomal membrane permeation. This study indicates the safety aspect of perovskite NMs and may guide the rational design of perovskite NMs with more biocompatibility during their manufacture and application.

Effectiveness and safety of tocilizumab in patients with refractory or severe Takayasu's arteritis: A prospective cohort study in a Chinese population

OBJECTIVE

To assess the effectiveness and safety of tocilizumab (TCZ) in treating severe/refractory Takayasu's arteritis (TAK).

METHODS

A prospective cohort study was started on 1 November 2013 and terminated on 10 June 2020. Thirty-seven patients diagnosed as severe/refractory TAK, treated with TCZ combined with or without immunosuppressors were enrolled. Treatment response (complete remission (CR) and partial remission (PR)), imaging progression and side effects were analyzed at 6-month treatment. Disease flare was analyzed during the remaining follow-up.

RESULTS

The CR and RR rates were 70% and 88% at 6 months of TCZ treatment, respectively. Glucocorticoids was tapered from 30.0 (20.0-40.0) to 15.0 (10.0-15.0) mg/day at 6 months. Younger patients (≤26 years) (OR=14.6, 95% CI 1.27-170.4, P<0.05) and those with involvement of bilateral carotid arteries or vertebral arteries (OR=14.6, 95% CI 1.27-169.1, P<0.05) might show a better response to TCZ at 6 months. Combined therapy of immunosuppressors had no significant effects on the effectiveness of TCZ at 6 months. Among the total 23 patients with CR at 6 months, 14 cases discontinued TCZ therapy after 6 months, and disease flare was observed in six ones (43%), with medium flare at 7 (7-9.8) months. One patient (11%) who continued TCZ therapy suffered disease flare at 8 months. Infections were the most commonly observed side effects (38%), with four patients discontinuing TCZ treatment due to severe infections.

CONCLUSION

TCZ treatment achieved a favorable response with acceptable adverse effects for TAK.

Effect of hydroxychloroquine on angiographic progression in routine treatment of Takayasu arteritis

OBJECTIVES

Hydroxychloroquine (HCQ), an anti-malarial drug, is widely used in the treatment of rheumatic diseases. However, the benefits of HCQ in the treatment of Takayasu arteritis (TA) remain unclear, especially in terms of alleviation of vascular progression.

METHODS

This longitudinal observational retrospective study was based on the East China TA cohort. Patients received routine treatment with prednisone and immunosuppressants. Fifty TA patients who underwent magnetic resonance angiography two times within a 1.5-year follow-up period of monitoring vascular changes were divided into HCQ and non-HCQ groups according to whether HCQ was prescribed. Changes in angiographic features were compared. Multivariate Cox regression analysis was employed to further validate the results.

RESULTS

Of 50 TA patients, 21 were prescribed HCQ. The two groups shared a similar disease course, vascular types, prednisone with immunosuppressants intervention strategy, globin level, and disease remission rate at 6 months. The HCQ group showed greater reduction in the inflammatory indices erythrocyte sedimentation rate and C-reactive protein (CRP) level (p < .05), and a significantly lower incidence of angiographic progression than the non-HCQ group (19.0% vs. 51.7%, p = .035). After adjustment for age and usage of tocilizumab, angiographic progression was found to be independently associated with CRP (hazard ratio [95% confidence interval], HR [95% CI]: 1.102 [1.000-1.024], p = .046), and the usage of HCQ (HR [95% CI]: 0.266 [0.075-0.940], p = .040).

CONCLUSION

HCQ enhanced the anti-inflammatory effect of routine treatment strategies with prednisone and immunosuppressants, and alleviated angiographic progression in TA.

Serum complement 3 is a potential biomarker for assessing disease activity in Takayasu arteritis

BACKGROUND

Takayasu arteritis (TA) is a rare disease, lacking convenient and feasible biomarkers to identify disease activity. We aimed to evaluate the value of complements in distinguishing active TA.

METHODS

Consecutive patients were enrolled from the prospective East China TA cohort from April 2008 to June 2019. Patients were divided into two groups according to their baseline Kerr score. The value of complements and other biomarkers in identifying disease activity were analysed with cluster analysis, ROC curves, and combined tests. An independent group of patients from July 2019 to December 2019 were employed to validate the results.

RESULTS

Of the enrolled 519 patients, 406 (72.2%) cases were identified as active disease. Higher erythrocyte sedimentation rate (ESR), C-reactive protein (CRP), interleukin-6 (IL-6), and complement 3 (C3) levels were observed in the active group. Elevated C3 (≥ 1.085 g/L) had a high value to identify active TA with a sensitivity of 69.9%, specificity of 66.7%, and AUC of 0.715. Combining the CRP (≥ 10.65 g/L; sensitivity, 50.7%; specificity, 82.4%) and C3, the sensitivity could be improved to 85.1% in parallel test and the specificity could be improved to 94.1% in serial test. Validation was further performed to confirm the value of C3 for disease activity assessment. The accuracy of the parallel test of CRP and C3 in external validation with independent 53 TA cases was 72.73% with the AUC of 0.721.

CONCLUSION

Elevated C3 could effectively evaluate the disease activity of TA, and C3 combining with CRP could further improve the disease activity evaluation.

Nebivolol is more effective than atenolol for blood pressure variability attenuation and target organ damage prevention in L-NAME hypertensive rats

β-Adrenergic blockers are no longer recommended as first-line therapy due to the reduced cardioprotection of traditional β-blockers compared with other antihypertensive drugs. It is unknown whether third-generation β-blockers share the limitations of traditional β-blockers. The aim of the present study was to compare the effects of nebivolol or atenolol on central and peripheral systolic blood pressure (SBP) and its variability and target organ damage (TOD) in N-nitro-L-arginine methyl ester (L-NAME) hypertensive rats. Male Wistar rats were treated with L-NAME for 8 weeks together with oral administration of nebivolol 30 mg/kg (n = 8), atenolol 90 mg/kg (n = 8), or vehicle (n = 8). The control group was composed of vehicle-treated Wistar rats. SBP and its variability, as well as echocardiographic parameters, were assessed during the last 2 weeks of treatment. Tissue levels of tumor necrosis factor-α (TNF-α), interleukin-6 (IL-6) and transforming growth factor β (TGF-β), and histopathological parameters were evaluated in the left ventricle and aorta. Nebivolol had a greater ability than atenolol to decrease central SBP and mid-term and short-term blood pressure variability (BPV) in L-NAME rats. Echocardiographic analysis showed that nebivolol was more effective than atenolol on E/A wave ratio normalization. Compared with atenolol treatment, nebivolol had a greater protective effect on different TOD markers, inducing a decrease in collagen deposition and a reduction in the proinflammatory cytokines IL-6 and TNF-α in the left ventricle and aorta. Our findings suggest that the adverse hemodynamic profile and the reduced cardiovascular protection reported with traditional β-blockers must not be carried forward to third-generation β-blockers.