Antifibrogenic effects of C-C chemokine receptor type 2 antagonist in a bleomycin-induced scleroderma model

A vascularized breast cancer spheroid platform for the ranked evaluation of tumor microenvironment-targeted drugs by light sheet fluorescence microscopy

Targeting the supportive tumor microenvironment (TME) is an approach of high interest in cancer drug development. However, assessing TME-targeted drug candidates presents a unique set of challenges. We develop a comprehensive screening platform that allows monitoring, quantifying, and ranking drug-induced effects in self-organizing, vascularized tumor spheroids (VTSs). The confrontation of four human-derived cell populations makes it possible to recreate and study complex changes in TME composition and cell-cell interaction. The platform is modular and adaptable for tumor entity or genetic manipulation. Treatment effects are recorded by light sheet fluorescence microscopy and translated by an advanced image analysis routine in processable multi-parametric datasets. The system proved to be robust, with strong interassay reliability. We demonstrate the platform's utility for evaluating TME-targeted antifibrotic and antiangiogenic drugs side-by-side. The platform's output enabled the differential evaluation of even closely related drug candidates according to projected therapeutic needs.

Targeting transitioning lung monocytes/macrophages as treatment strategies in lung disease related to environmental exposures

BACKGROUND

Environmental/occupational exposures cause significant lung diseases. Agricultural organic dust extracts (ODE) and bacterial component lipopolysaccharide (LPS) induce recruited, transitioning murine lung monocytes/macrophages, yet their cellular role remains unclear.

METHODS

CCR2 RFP+ mice were intratracheally instilled with high concentration ODE (25%), LPS (10 μg), or gram-positive peptidoglycan (PGN, 100 μg) for monocyte/macrophage cell-trafficking studies. CCR2 knockout (KO) mice and administration of intravenous clodronate liposomes strategies were employed to reduce circulating monocytes available for lung recruitment following LPS exposure. Lung tissues and bronchoalveolar lavage fluid (BALF) were collected. Pro-inflammatory and/or pro-fibrotic cytokines, chemokines, and lung extracellular matrix mediators were quantitated by ELISA. Infiltrating lung cells including monocyte/macrophage subpopulations, neutrophils, and lymphocytes were characterized by flow cytometry. Lung histopathology, collagen content, vimentin, and post-translational protein citrullination and malondialdehyde acetaldehyde (MAA) modification were quantitated. Parametric statistical tests (one-way ANOVA, Tukey'smultiple comparison) and nonparametric statistical (Kruskal-Wallis, Dunn's multiple comparison) tests were used following Shapiro-Wilk testing for normality.

RESULTS

Intratracheal instillation of ODE, LPS, or PGN robustly induced the recruitment of inflammatory CCR2+ CD11cintCD11bhi monocytes/macrophages and both CCR2+ and CCR2- CD11c-CD11bhi monocytes at 48 h. There were also increases in CCR2+ CD4+ and CD8+ T cells and NK cells. Despite reductions in LPS-induced lung infiltrating CD11cintCD11bhi cells (54% reduction), CCR2 knockout (KO) mice were not protected against LPS-induced inflammatory and pro-fibrotic consequences. Instead, compensatory increases in lung neutrophils and CCL2 and CCL7 release occurred. In contrast, the depletion of circulating monocytes through the administration of intravenous clodronate (vs. vehicle) liposomes 24 h prior to LPS exposure reduced LPS-induced infiltrating CD11cintCD11bhi monocyte-macrophage subpopulation by 59% without compensatory changes in other cell populations. Clodronate liposome pre-treatment significantly reduced LPS-induced IL-6 (66% reduction), matrix metalloproteinases (MMP)-3 (36%), MMP-8 (57%), tissue inhibitor of metalloproteinases (61%), fibronectin (38%), collagen content (22%), and vimentin (40%). LPS-induced lung protein citrullination and MAA modification, post-translational modifications implicated in lung disease, were reduced (39% and 48%) with clodronate vs. vehicle liposome.

CONCLUSION

Highly concentrated environmental/occupational exposures induced the recruitment of CCR2+ and CCR2- transitioning monocyte-macrophage and monocyte subpopulations and targeting peripheral monocytes may reduce the adverse lung consequences resulting from exposures to LPS-enriched inhalants.

Study on Potential Differentially Expressed Genes in Idiopathic Pulmonary Fibrosis by Bioinformatics and Next-Generation Sequencing Data Analysis

Idiopathic pulmonary fibrosis (IPF) is a chronic progressive lung disease with reduced quality of life and earlier mortality, but its pathogenesis and key genes are still unclear. In this investigation, bioinformatics was used to deeply analyze the pathogenesis of IPF and related key genes, so as to investigate the potential molecular pathogenesis of IPF and provide guidance for clinical treatment. Next-generation sequencing dataset GSE213001 was obtained from Gene Expression Omnibus (GEO), and the differentially expressed genes (DEGs) were identified between IPF and normal control group. The DEGs between IPF and normal control group were screened with the DESeq2 package of R language. The Gene Ontology (GO) and REACTOME pathway enrichment analyses of the DEGs were performed. Using the g:Profiler, the function and pathway enrichment analyses of DEGs were performed. Then, a protein-protein interaction (PPI) network was constructed via the Integrated Interactions Database (IID) database. Cytoscape with Network Analyzer was used to identify the hub genes. miRNet and NetworkAnalyst databaseswereused to construct the targeted microRNAs (miRNAs), transcription factors (TFs), and small drug molecules. Finally, receiver operating characteristic (ROC) curve analysis was used to validate the hub genes. A total of 958 DEGs were screened out in this study, including 479 up regulated genes and 479 down regulated genes. Most of the DEGs were significantly enriched in response to stimulus, GPCR ligand binding, microtubule-based process, and defective GALNT3 causes HFTC. In combination with the results of the PPI network, miRNA-hub gene regulatory network and TF-hub gene regulatory network, hub genes including LRRK2, BMI1, EBP, MNDA, KBTBD7, KRT15, OTX1, TEKT4, SPAG8, and EFHC2 were selected. Cyclothiazide and rotigotinethe are predicted small drug molecules for IPF treatment. Our findings will contribute to identification of potential biomarkers and novel strategies for the treatment of IPF, and provide a novel strategy for clinical therapy.

CC chemokines family in fibrosis and aging: From mechanisms to therapy

Fibrosis is a universal aging-related pathological process in the different organ, but is actually a self-repair excessive response. To date, it still remains a large unmet therapeutic need to restore injured tissue architecture without detrimental side effects, due to the limited clinical success in the treatment of fibrotic disease. Although specific organ fibrosis and the associated triggers have distinct pathophysiological and clinical manifestations, they often share involved cascades and common traits, including inflammatory stimuli, endothelial cell injury, and macrophage recruitment. These pathological processes can be widely controlled by a kind of cytokines, namely chemokines. Chemokines act as a potent chemoattractant to regulate cell trafficking, angiogenesis, and extracellular matrix (ECM). Based on the position and number of N-terminal cysteine residues, chemokines are divided into four groups: the CXC group, the CX3C group, the (X)C group, and the CC group. The CC chemokine classes (28 members) is the most numerous and diverse subfamily of the four chemokine groups. In this Review, we summarized the latest advances in the understanding of the importance of CC chemokine in the pathogenesis of fibrosis and aging and discussed potential clinical therapeutic strategies and perspectives aimed at resolving excessive scarring formation.

Therapeutic CCR2 Blockade Prevents Inflammation and Alleviates Myxomatous Valve Disease in Marfan Syndrome

Myxomatous valve disease (MVD) can lead to cardiac dysfunction and heart failure, yet medical therapies are lacking. C-C chemokine receptor type 2 (CCR2)+ immune cell infiltration promotes mitral valve inflammation in a Marfan syndrome (MFS) mouse model. The CCR2 genetic knockout reduces inflammation with downregulated proteases and improved extracellular matrix integrity. Pharmacological inhibition of CCR2+ cell infiltration by RS504393 prevents the initiation and progression of MVD, indicated by restored protease expression, improved extracellular matrix organization, and reduced valve leaflet thickness in MFS mice. Thus, the CCR2 antagonist RS504393 is a promising therapy for the treatment of MVD in MFS.

ACKR2 limits skin fibrosis and hair loss through IFN-β

The resolution of inflammation facilitates proper wound healing and limits tissue repair short of exaggerated fibrotic scarring. The atypical chemokine receptor (ACKR)2/D6 scavenges inflammatory chemokines, while IFN-β is a recently unveiled pro-resolving cytokine. Both effector molecules limit acute inflammatory episodes and promote their resolution in various organs. Here, we found fibrotic skin lesions from ACKR2^-/- mice presented increased epidermal and dermal thickening, atrophy of the subcutaneous adipose tissue, augmented disorientation of collagen deposition, and enhanced deformation and loss of hair follicles compared to WT counterparts. In addition, affected skin sections from ACKR2^-/- mice contained reduced levels of the pro-resolving mediators IFN-β and IL-10, but increased levels of the pro-inflammatory chemokines CCL2 and 3, the pro-fibrotic cytokine TGF-β, and the immune-stimulating cytokine IL-12. Notably, treatment with exogenous IFN-β rescued, at least in part, all the pro-fibrotic outcomes and lesion size in ACKR2^-/- mice and promoted expression of the pro-resolving enzyme 12/15-lipoxygenase (LO) in both ACKR2^-/- and WT mice. Moreover, Ifnb^-/- mice displayed enhanced pro-fibrotic indices upon exposure to bleomycin. These findings suggest ACKR2 is an important mediator in limiting inflammatory skin fibrosis and acts via IFN-β production to promote the resolution of inflammation and minimize tissue scaring.

The roles of MCP-1/CCR2 mediated macrophage recruitment and polarization in bladder outlet obstruction (BOO) induced bladder remodeling

Bladder outlet obstruction (BOO) can lead to alternation of bladder structure and function, known as bladder remodeling. Macrophage is a heterogeneous cell type and implicated in immunity regulating and tissue repairment. The relationship between macrophage and BOO remains unclear. We determined the pivotal role of macrophage recruitment and polarization in bladder remodeling. Sprague-Dawley rats underwent surgical operation of a BOO for either 1, 3, 6 weeks and were compared with sham-operated rats. The BOO rats in the experimental group were orally administrated with 5 mg/kg RS-504393, a C-C chemokine receptor (CCR2) antagonist, for 6 weeks, and the rats in the control group were treated with vehicle. Bladder tissues were harvested for assays of flow cytometry, quantitative reverse transcription polymerase chain reaction, histological examinations, immunohistochemistry staining and immunofluorescence. After induction of BOO, M1 macrophages were predominantly observed at inflammatory stage while M2 macrophages were mainly found during fibrosis stage. Flow cytometry analysis revealed that the ratio of M1/M2 significantly increased at 3 weeks (P = 0.0013) when compared to the sham-operated group. Interestingly, our results showed that M2 macrophages promoted BOO-induced fibrosis through indirectly secreting TGF-β and directly transforming to collagen-producing myofibroblast. Additionally, RS-504393 treatment significantly decreased the number of M1 and M2 macrophage infiltration in bladder tissue, and bladder fibrosis was attenuated by RS-504393 treatment compared with that in the vehicle-treated rats. In summary, macrophages play a pivotal role in bladder remodeling and targeting MCP-1/CCR2 signaling pathway might be a therapeutic strategy for human bladder fibrosis.

A Review of the Evidence for and against a Role for Mast Cells in Cutaneous Scarring and Fibrosis

Scars are generated in mature skin as a result of the normal repair process, but the replacement of normal tissue with scar tissue can lead to biomechanical and functional deficiencies in the skin as well as psychological and social issues for patients that negatively affect quality of life. Abnormal scars, such as hypertrophic scars and keloids, and cutaneous fibrosis that develops in diseases such as systemic sclerosis and graft-versus-host disease can be even more challenging for patients. There is a large body of literature suggesting that inflammation promotes the deposition of scar tissue by fibroblasts. Mast cells represent one inflammatory cell type in particular that has been implicated in skin scarring and fibrosis. Most published studies in this area support a pro-fibrotic role for mast cells in the skin, as many mast cell-derived mediators stimulate fibroblast activity and studies generally indicate higher numbers of mast cells and/or mast cell activation in scars and fibrotic skin. However, some studies in mast cell-deficient mice have suggested that these cells may not play a critical role in cutaneous scarring/fibrosis. Here, we will review the data for and against mast cells as key regulators of skin fibrosis and discuss scientific gaps in the field.