Development Of Fibrosis Research Articles

The role of SGLT1 in atrial fibrillation and its relationship with endothelial-mesenchymal transition.

Atrial fibrillation (AF) is a prevalent arrhythmia closely associated with atrial fibrosis, posing significant challenges to cardiovascular health. Recent studies have identified the sodium-glucose co-transporter 1 (SGLT1) as a potential key player in the pathophysiology of heart diseases, particularly in the context of AF and atrial fibrosis. This review aims to synthesize current knowledge regarding the mechanisms by which SGLT1 influences the development of AF and atrial fibrosis, with a specific focus on its relationship with endothelial-mesenchymal transition (EMT). By analyzing the latest research findings, this paper discusses how SGLT1 may modulate structural and functional changes in the atria, thereby enhancing our understanding of the underlying mechanisms driving AF.

Steatohepatitis-induced vascular niche alterations promote melanoma metastasis

BackgroundIn malignant melanoma, liver metastases significantly reduce survival, even despite highly effective new therapies. Given the increase in metabolic liver diseases such as metabolic dysfunction-associated steatotic liver disease (MASLD) and metabolic dysfunction-associated steatohepatitis (MASH), this study investigated the impact of liver sinusoidal endothelial cell (LSEC)-specific alterations in MASLD/MASH on hepatic melanoma metastasis.MethodsMice were fed a choline-deficient L-amino acid-defined (CDAA) diet for ten weeks to induce MASH-associated liver fibrosis, or a CDAA diet or a high fat diet (HFD) for shorter periods of time to induce early steatosis-associated alterations. Liver metastasis formation was assessed using melanoma cell lines B16F10Luc2 and Wt31. LSEC-specific GATA4 knockout mice (Gata4LSEC−KO/BL) developing MASH-like liver fibrosis without steatosis via a pathogenic angiocrine switch were included to compare the impact of liver fibrosis versus hepatic steatosis on hepatic melanoma metastasis. Bulk RNA-Seq of isolated LSECs from CDAA-fed and control mice was performed. Levels of adhesion molecules (VCAM1, ICAM1, E-selectin) were monitored, and ICAM1 and VCAM1 antibody therapy was employed.ResultsFeeding a CDAA diet, in contrast to a HFD, led to increased metastasis before the development of liver fibrosis. Gata4LSEC−KO/BL mice characterized by vascular changes ensuing perisinusoidal liver fibrosis without steatosis also exhibited increased metastasis. Early molecular alterations in the hepatic vascular niche, rather than fibrosis or steatosis, correlated with metastasis, as shown by LSEC dedifferentiation and upregulation of endothelial adhesion molecules. The metastatic process in CDAA-fed mice was also dependent on the respective melanoma cell lines used and on the route of their metastatic spread. ICAM1 inhibition, but not VCAM1 inhibition reduced melanoma cell retention.ConclusionWe discovered that the hepatic vascular niche acts as a delicate sensor to even short-term nutritional alterations during the development of MASLD/MASH. The dynamic adaptations to the metabolic challenges of developing MASLD/MASH caused an early shift from the normal hepatic vascular niche to a pre-metastatic vascular niche that promoted hepatic melanoma metastasis in the context of cell-autonomous and acquired melanoma cell features. Altogether, our findings provide a potential avenue for angiotargeted therapies to prevent hepatic melanoma metastasis.

M6A modified ATG9A is required in regulating autophagy to promote HSCs activation and liver fibrosis.

Hepatic stellate cells (HSCs) are the central link of the occurrence and development of hepatic fibrosis, and autophagy promotes HSCs activation. N6-methyladenosine (m6A) RNA modification can also control autophagy by targeting selected autophagy-associated genes. but up to now, little research has been done on the m6A modification autophagy-related genes (ATGs) in hepatic fibrosis. Here, we identify ATG9A as a previously unrecognized m6A modified ATG using m6A-sequencing (m6A-seq). Importantly, ATG9A is upregulated in liver fibrosis mice and primary biliary cirrhosis (PBC) patient liver tissue. Mechanistically, based on the presence of m6A binding sites on ATG9A, ATG9A promotes HSCs autophagy in an m6A dependent manner, thereby enhancing HSCs activation. Noteworthy, FTO is identified as the upstream of ATG9A, and knockdown of ATG9A can prevent FTO-induced HSCs autophagy and activation. In bile duct ligation (BDL) or CCL4-induced liver fibrosis mouse models, lowering ATG9A alleviated liver fibrosis through PI3K/AKT/mTOR pathway and TGFβ1/smad3 pathway. Taken together, our results provided that ATG9A is a potential prognostic biomarker and therapeutic target for patients with liver fibrosis.

From Dysbiosis to Hepatic Inflammation: A Narrative Review on the Diet-Microbiota-Liver Axis in Steatotic Liver Disease

The gut microbiota has emerged as a critical player in metabolic and liver health, with its influence extending to the pathogenesis and progression of steatotic liver diseases. This review delves into the gut-liver axis, a dynamic communication network linking the gut microbiome and liver through metabolic, immunological, and inflammatory pathways. Dysbiosis, characterized by altered microbial composition, contributes significantly to the development of hepatic steatosis, inflammation, and fibrosis via mechanisms such as gut barrier dysfunction, microbial metabolite production, and systemic inflammation. Dietary patterns, including the Mediterranean diet, are highlighted for their role in modulating the gut microbiota, improving gut-liver axis integrity, and attenuating liver injury. Additionally, emerging microbiota-based interventions, such as fecal microbiota transplantation and bacteriophage therapy, show promise as therapeutic strategies for steatotic liver disease. However, challenges such as population heterogeneity, methodological variability, and knowledge gaps hinder the translational application of current findings. Addressing these barriers through standardized approaches and integrative research will pave the way for microbiota-targeted therapies to mitigate the global burden of steatotic liver disease.

Spinal cord injury induces transient activation of hepatic stellate cells in rat liver

Spinal cord injury (SCI) causes abnormal liver function, the development of metabolic dysfunction-associated steatotic liver disease features and metabolic impairment in patients. Experimental models also demonstrate acute and chronic changes in the liver that may, in turn, affect SCI recovery. These changes have collectively been proposed to contribute to the development of a SCI-induced metabolic dysfunction-associated steatohepatitis (MASH). However, none of the existent studies have focused on hepatic stellate cells (HSCs), liver resident cells that are the primary drivers of collagen deposition and fibrosis following sustained liver damage. Here, we describe the transient activation of HSCs after a thoracic contusion in rats, considered a clinically relevant model of experimental SCI. We studied HSC during the time course of SCI, from 1 to 45 days post injury. We found a transient activation of HSCs after SCI, beginning with the acute downregulation of Glial Fibrillar Acidic Protein 1dpi. This is followed by a morphological and phenotypical transformation into alpha-smooth muscle actin (ACTA2/SMA) immunoreactive myofibroblast-like cells, peaking at 14 days post-injury and returning to control-like levels at later timepoints (45 days post-injury). These changes are not accompanied by fibrosis development but collagen deposition in peri-portal areas is observed at 45 days.

DOP133 Spatiotemporal analysis of Crohn’s disease reveals PECAM2 signaling at the basis of inflammation-to-fibrosis transition

Abstract Background Crohn’s disease is a chronic inflammatory disease of the bowel often complicated by fibrotic strictures(1,2,3). Medical treatment is lacking, and surgery is commonly required(3). The mechanisms underlying the progression from chronic inflammation to fibrosis are not yet defined. We aim to unravel Crohn’s disease pathogenesis using cutting-edge computational and bioinformatics tools (Figure 1). Methods Spatial transcriptomics was performed on 13 surgical specimens of inflamed and fibrotic Crohn’s disease and healthy controls. Spatial transcriptomics results were integrated with single-cell data to track the cellular and molecular evolution from healthy intestine to fibrosis by employing CellChat(4) and pseudotime analysis. Computational data were confirmed by immunostaining of tissues from an independent cohort of Crohn’s patients. Results We demonstrated that intestinal cytoarchitecture was rearranged while chronic inflammation progressed. Crohn’s disease-associated fibrosis evolved within the mesenchymal compartment, driven by PECAM2 signaling through PECAM1-CD38 interaction. Notably, CD38 positivity was found in the mesenchymal compartment in an independent cohort of Crohn’s disease patients. In parallel, ApoA signaling, particularly APOA1-ABCA interaction, emerged as relevant for maintaining epithelial and stromal homeostasis, while its downregulation was associated with fibrosis development (Figure 2). Conclusion Our results provide insights into CD38-driven fibrosis and suggest that PECAM2 signaling blockade could reduce the development of strictures in patients with Crohn’s disease, potentially offering a new treatment target.

The role of SMooth muscle cell minerAlocorticoid Receptor in inTestinal fibrosis (SMART)

Abstract Background and aims Intestinal fibrosis is a common complication in inflammatory bowel diseases (IBD) with no specific therapy1. Because mineralocorticoid receptor (MR) antagonism prevented inflammation and fibrosis in extra-intestinal organs but also in intestine and since we showed that smooth muscle cell (SMC)-MR deletion prevented colon fibrosis development in mice, we now aim to understand the underlying mechanisms of these benefits. Methods Fibrosis will be assessed in male and female mice with conditioned smooth muscle MR overexpression. We previously demonstrated that NGAL (Lipocalin-2) is a MR target in murine SMC and is involved in MR-mediated fibrosis and inflammation. We therefore will study the impact of MR or NGAL agonism/antagonism in murine SMC upon TGF-beta stimulation. To understand the potential inducers of MR or NGAL in murine SMC, we will screen the ability of microbial factors to induce fibrosis or MR signalling in intestinal fibroblasts or SMC. To assess the role of MR/NGAL signaling in macrophages/SMC interaction, we will also investigate the impact of myeloid MR or NGAL invalidation on SMC activation in co-culture experiments of murine macrophages and SMC. For translational approaches, conditioned medium of intestinal biopsies from Crohn’s disease (CD) patients or isolated monocytes derived macrophages from CD patients will be incubated with SMC to study their impact of MR/NGAL signalling and/or fibrosis development. Anticipated impact SMART may open new therapeutic avenues in IBD by the repositioning of MR antagonists already available in other medical applications. As SMC represent the main cell component of the increased wall thickness in intestinal fibrosis, a better understanding of the crosstalk between SMC, macrophages and gut microbiota will provide novel insights to develop potentially more effective therapies targeting stromal cells.

P0120 Study of the Implication of the Epithelium in the Development and Progression of Fibrosis in Ulcerative Colitis

Abstract Background Ulcerative colitis (UC) is a chronic inflammatory bowel disease (IBD) with diffuse colonic mucosal inflammation. Fibrosis has been observed in the submucosa and muscularis mucosae even without active inflammation2, yet remains underexplored in UC. No anti-fibrotic treatments currently exist for IBD4. At the epithelial level, IBD-related endoplasmic reticulum stress (ERS) and inflammation upregulate ER chaperones like AGR2, which, when secreted extracellularly (eAGR2), can induce fibroblast-to-myofibroblast transition (FMT), suggesting a role in fibrosis3. Our aim is to use a pro-fibrotic organoid model from UC patients and controls to study the epithelium’s role in fibrosis, focusing on AGR2’s paracrine action Methods Apical-out organoids were derived from intestinal stem cells of UC patients and controls1. ERS was induced with Tunicamycin (Tm), followed by recovery in fresh medium, to observe epithelial responses post-stress, assessing paracrine effects. Transcripts, proteins, and supernatants were analyzed for ERS markers, epithelial-mesenchymal transition (EMT), pro-fibrotic markers (TGF-β, eAGR2), and cytokines. Immunofluorescence (IF) was performed for AGR2 and sXBP1. Conditioned supernatants were used to expose intestinal fibroblasts (CCD18-Co) to assess FMT by IF (α-SMA increase), confirming the pro-fibrotic phenotype of UC organoids. Forty-four UC patients (198 slides) were scored for inflammation (Geboes score), fibrosis2, and ERS markers (AGR2/BiP staining) Results Organoids from UC patients and controls showed increased ERS markers (RT-qPCR: BiP/CHOP/sXBP1 fold change 6-16, 4-9.5, and 3-8), with minimal variation in pro-inflammatory cytokines and TGF-β. AGR2 expression increased post-ERS compared to control (Tm/CTL: 2-10). Intracellular AGR2, BiP, and ERP72 rose in parallel with ERS induction. IF showed increased AGR2 and sXBP1, with AGR2 redistributing from the apical pole and diffusing across the organoid under ERS. Active eAGR2 levels in supernatants increased post-ERS (Tm/CTL eAGR2 range: 1.5 to 3). CCD18-Co assays with supernatants showed elevated α-SMA, confirming FMT. ERS was confirmed in UC tissues, with stronger chaperone signals associated with inflammation and fibrosis. Conclusion We developed a model for studying ERS-induced epithelial responses in UC. Apical-out UC organoids exposed to ERS demonstrate a pro-fibrotic paracrine effect independent of pro-inflammatory/pro-fibrotics markers, suggesting that ERS in IBD may promote intestinal fibrosis. The specific role of eAGR2 in this phenotype is under investigation, focusing on transcriptomic and secretomic shifts accompanying ERS responses in UC organoids References 1)Co, J. Y., et al. (2021). Controlling the polarity of human gastrointestinal organoids to investigate epithelial biology and infectious diseases. In Nature Protocols. https://doi.org/10.1038/s41596-021-00607-0 2)Gordon, I. O., et al. (2018). Fibrosis in ulcerative colitis is directly linked to severity and chronicity of mucosal inflammation. Alimentary Pharmacology and Therapeutics. https://doi.org/10.1111/apt.14526 3)Vieujean, S., et al. (2021). Potential Role of Epithelial Endoplasmic Reticulum Stress and Anterior Gradient Protein 2 Homologue in Crohn’s Disease Fibrosis. Journal of Crohn’s and Colitis. https://doi.org/10.1093/ecco-jcc/jjab061 4)F. C. EDWARDS and S. C. TRUELOVE, “the Course and Prognosis of Ulcerative Colitis. Iii. Complications.,” Gut, vol. 5, pp. 1–22, 1964

P0082 Proteomic profiling of colonic mucosa in patients with ulcerative colitis: detection of molecular patterns of inflammation.

Abstract Background The mechanisms of recurrence and progression of ulcerative colitis (UC) require detailed study. Modern advances in proteomic analysis methods are ideal for studying the molecular characteristics of inflammation in the colonic mucosa (CM) of UC patients. Methods The study was comparative cohort with parallel design and included 88 patients (range from 22 to 35 years, 37 men and 51 women): 53 (60.2%) pancolitis and 35 (39.8%) left-sided UC, mild and moderate activity. The duration of UC was 5.3 years. The control group included 30 healthy individuals. Biosamples of CM in patients with UC in the active stage and in healthy persons were received by ileocolonoscopy with CM biopsy. The separation of individual proteins of CM was based on technologies of IEF, SDS-PAGE, 2DPAGE, by standard sets (MB-HIC C8 Kit, MB-IMAC Cu, MB-Wax Kit, «Bruker», USA). Automated mass spectrometry imaging was performed by MALDI-TOF-MS/MS, Ultraflex II, «Bruker», USA). The partially identified sequences were then submitted to “BLAST protein-protein” and screened against the Homo sapiens Swissprot database to check if this identification matched the MASCOT-identification (Matrix Science, UK). The data of the molecular interactions and functional features of proteins were received with STRING 10 database. Results Based on the data of standard methods of identification of UC and molecular phenotyping of colon mucosa we conducted new prognostic markers, molecular pathways of UC and diagnostic tests in patients with UC. We identified functional groups of peptides and proteins in molecular patterns of CM (fig. 1). SMAD family member 2 (SMAD2) activates the transcription of TFG1β, that leads the development of fibrosis in colon submucosa in UC patients; the stimulation of the expression of apoС-III in affected CM in UC is associated with the activation of the FOXO1 signaling pathway that supports inflammatory processes; caspase 8 protects colonocytes from TNFα-induced cell death through a necroptosis mechanism via the blockade of the RIP3 expression. Significant decrease of the expression of PPARγ promotes the activation of STAT and AP-1 signaling pathways, that promotes the increase of the synthesis of IL-2, 6, 8, 12,TNFα, matrix metalloproteinases, the activity of immune and inflammation processes in colon mucosa. The reduction of expression of β-defensin-1 in cells of colon mucosa are accompanied with increased expression of CCR6, that promotes the formation of inflammatory infiltrates in colonic submucosa in UC.The molecular interactions of β-defensin-1 are presented on figure 2. Conclusion Bioinformatics analysis revealed the presence of the new potentially markers of the progression UC, that’s may provide for the development of novel diagnostic tests for UC.

P0007 mAb-based targeting of the eAGR2-Fibrinogen interaction as a promising new therapy in Inflammatory Bowel Disease

Abstract Background Historically, Fibrinogen (Fg) is known to be crucial in IBD by aiding fibrin deposition, which leads to scar tissue formation and tissue remodeling. High Fg levels in IBD foster chronic inflammation, activate fibroblasts, stimulate extracellular matrix production, promote fibrosis, and hinder normal mucosal repair. Recently, Anterior Gradient 2 (AGR2), an endoplasmic reticulum chaperone protein that is expressed by mucin-secreting epithelial cells, is secreted (eAGR2) under stress and contributes to a plethora of pathogenic processes (e.g. epithelial integrity disruption, monocyte attraction, fibroblast activation, and oncogenesis). AGR2 overexpression in the colon of IBD patients correlates with disease severity and activity. The present report identifies the eAGR2-Fg physical interaction, which opens new therapeutic avenues in IBD care. Methods CoIP-MS was used to identify interactors of eAGR2 in Caco2 supernatant. The binding between AGR2 and interactors was orthogonally validated using ELISA and abrogated by proprietary anti-eAGR2 mAb (TH-009). The efficacy of TH-009 in preventing the development of fibrosis was assessed using a murine chronic DSS model of colitis. Results IP-MS identified the three Fg subunits as the most abundant eAGR2 interactors in the Caco-2 supernatant. This interaction decreased fourfold with anti-eAGR2 mAbs. ELISA confirmed the specific binding of Fg to AGR2 (p<0.01), which was abrogated by TH-009 in a dose-dependent manner (p<0.001). In a murine chronic DSS model of colitis, multiple features of inflammation and fibrosis went down significantly when treated with TH-009, and anti-inflammatory molecular signature was promoted. For example, fibrosis was decreased by two-fold in TH-009 treated mice compared to that in the untreated DSS group (p<0.001). Also, collagen deposition and aSMA were decreased by 2.4 and 17-fold, respectively (p<0.001). At the mRNA level, a 2-fold decrease of TGFb, and fibronectin and a 3-fold decrease of ColA1 were observed (p=0,05; p<0.05 and p<0.01). Conclusion We identified Fg as a central eAGR2 partner and showed that this interaction was disrupted by the anti-eAGR2 mAb. Our results may suggest that eAGR2 binding to Fg impairs the fibrinogen-fibrin maturation cycle, thus maintaining the deleterious signaling observed in IBD. Considering the TH-009 efficacy in preventing fibrosis in vivo, our results support the therapeutic interest of targeting the eAGR2-Fg complex in IBD and other mucosal inflammatory diseases.

Single-cell transcriptome analysis revealing mechanotransduction via the Hippo/YAP pathway in promoting fibroblast-to-myofibroblast transition and idiopathic pulmonary fibrosis development.

Idiopathic pulmonary fibrosis (IPF) is an irreversible and fatal interstitial lung disease, characterized by excessive extracellular matrix (ECM) secretion that disrupts normal alveolar structure. This study aims to explore the potential molecular mechanisms underlying the promotion of IPF development. Firstly, we compared the transcriptome and single-cell sequencing data from lung tissue samples of patients with IPF and healthy individuals. Subsequently, we conducted Gene Ontology (GO) and Kyoto Encyclopedia of Genes and Genomes (KEGG) enrichment analyses on the differentially expressed genes (DEGs). Furthermore, we employed sodium alginate hydrogels with varying degrees of crosslinking to provide differential mechanical stress, mimicking the mechanical microenvironment in vivo during lung fibrosis. On this basis, we examined cytoskeletal remodeling in fibroblasts MRC-5, mRNA expression of multiple related genes, immunofluorescence localization, and cellular proliferation capacity. Bioinformatics analysis revealed a series of DEGs associated with IPF. Further functional and pathway enrichment analyses indicated that these DEGs were primarily enriched in ECM-related biological processes. Single-cell sequencing data revealed that fibroblasts and myofibroblasts are the main contributors to excessive ECM secretion and suggested activation of mechanotransduction and the Hippo/YAP signaling pathway in myofibroblasts. Cellular experiments demonstrated that sodium alginate hydrogels with different stiffness can simulate different mechanical stress environments, thereby affecting cytoskeletal rearrangement and Hippo/YAP pathway activity in MRC-5 lung fibroblasts. Notably, high levels of mechanical stress promoted YAP nuclear translocation, increased expression of type I collagen and α-SMA, and enhanced proliferative capacity. Additionally, we also found that fibroblasts primarily participate in mechanotransduction through the Rho/ROCK and Integrin/FAK pathways under high mechanical stress conditions, ultimately upregulating the gene expression of CCNE1/2, CTGF, and FGF1. Our study uncovers the crucial role of cytoskeletal mechanotransduction in myofibroblast transformation and IPF development through activation of the Hippo/YAP pathway, providing new insights into understanding the pathogenesis of IPF.

P0191 The role of myeloid mineralocorticoid receptor and its target neutrophil gelatinase-associated lipocalin in mice with colitis

Abstract Background Intestinal fibrosis is a common complication in IBD patients with no specific treatment. In extra-intestinal conditions, mineralocorticoid receptor (MR) antagonism inhibits inflammation and fibrosis in different pathophysiological conditions. We previously showed that pharmacological antagonism of MR also inhibits experimental intestinal fibrosis through its target neutrophil gelatinase-associated lipocalin (NGAL). We now hypothesize that myeloid MR may promote the transition from inflammation to intestinal fibrosis by modulation of macrophage plasticity. We aimed to investigate whether myeloid MR or myeloid NGAL deletion prevents colitis development in mice. Methods Acute and chronic colitis were respectively induced by 1% dextran sodium sulfate (DSS) in myeloid MR knock-out (MyMR KO n=10, WT n= 5) and myeloid NGAL knock-out (MyNGAL KO n=6, WT n=8). Colon tissues were collected for quantitative PCR analysis of inflammatory (Il1, Il6, Arg1, Nos2, Retnla, Adgre1) and fibrotic markers (Col1a1, Tgfb1, Fn1, Mmp3, Mmp9, Igf1, Tnf, Timp1). Fecal calprotectin and lipocalin levels were analyzed by ELISA. Results Myeloid MR deletion significantly reduced colon TGFβ mRNA expression (P<0.05) but did not impact weight loss or intestinal permeability in mice. Myeloid NGAL deletion significantly reduced colitis-induced weight loss (P<0.05) and inhibited fibrosis markers such as collagen 1 and metalloproteinase mRNA expression in mice with chronic colitis (Figure 1). Myeloid MR or NGAL invalidation did not significantly affect fecal calprotectin and lipocalin levels in our experimental conditions. Conclusion In our pilot study, myeloid MR and myeloid NGAL deletion inhibits fibrosis development but further studies are required to confirm these findings.

Targeting allograft inflammatory factor-1 reprograms kidney macrophages to enhance repair.

The role of macrophages remains incompletely understood in kidney injury and repair. Their plasticity offers an opportunity to polarize them towards mediating injury resolution in both native and transplanted kidneys undergoing ischemia and/or rejection. Here, we show that infiltrating kidney macrophages augmented their AIF-1 expression after injury. Aif1 genetic deletion led to macrophage polarization towards a reparative phenotype while halting the development of kidney fibrosis. The enhanced repair was mediated by higher levels of anti-inflammatory and pro-regenerative markers leading to a reduction in cell death and increase in proliferation of kidney tubular epithelial cells following ischemic reperfusion injury. Adoptive transfer of Aif1-/- macrophages to Aif1+/+ mice conferred protection against ischemia reperfusion injury. Conversely, depletion of macrophages reversed the tissue-reparative effects in Aif1-/- mice. We further demonstrated an increased expression of AIF-1 in human kidney biopsies from native kidneys with acute kidney injury or chronic kidney disease, as well as in biopsies from kidney allografts undergoing acute or chronic rejection. We conclude that AIF-1 is a macrophage marker of renal inflammation, and its targeting uncouples macrophage reparative functions from profibrotic functions. Thus, therapies inhibiting AIF-1 when ischemic injury is inevitable have the potential to reduce the global burden of kidney disease.

Genetic deficiency or pharmacological inhibition of cGAS-STING signalling suppresses kidney inflammation and fibrosis.

Chronic kidney disease (CKD) is characterised by inflammation, which can lead to tubular atrophy and fibrosis. The molecular mechanisms are not well understood. In this study, we investigated the functional role of the cyclic GMP-AMP synthase (cGAS)- stimulator of interferon genes (STING) signalling in renal inflammation and fibrosis. Mice with global cGAS deficiency or global or myeloid cell-specific STING deficiency or wild-type mice treated with RU.521, a selective cGAS inhibitor, were used to examine the role of cGAS-STING signalling in renal inflammation and fibrosis in a preclinical model of obstructive nephropathy in vivo. Bone marrow-derived macrophages were used to determine whether tubular epithelial cell-derived DNA can activate cGAS-STING signalling in vitro. Following obstructive injury, cGAS-STING signalling was activated in the kidneys during the development of renal fibrosis. Mice with deficiency of cGAS or STING exhibited significantly less macrophage proinflammatory activation, myofibroblast formation, total collagen deposition, and extracellular matrix (ECM) protein production in the kidneys following obstructive injury. Pharmacological inhibition of cGAS with RU.521 reduced macrophage proinflammatory activation, suppressed myofibroblast formation, and attenuated kidney fibrosis following obstructive injury. Mechanistically, cGAS-STING signalling in macrophages is activated by double-stranded DNA released from damaged tubular epithelial cells, which induces inflammatory responses. Our study identifies the cGAS-STING signalling pathway as a critical regulator of macrophage proinflammatory activation during the development of renal fibrosis. Therefore, inhibition of cGAS-STING signalling may represent a novel therapeutic strategy for CKD.

Polystyrene microplastics induce liver fibrosis and lipid deposition in mice through three hub genes revealed by the RNA-seq

Nano- and microplastics (NMPs) have become a serious global environmental threat that causes damage to mammalian organs. In this work, we investigated the potential molecular mechanism underlying the development of liver fibrosis induced by long-term exposure to three different sized polystyrene (PS)-NMPs (80 nm, 0.5 µm and 5 µm) in mice. Liver fibrosis levels were evaluated in mice after chronic exposure to PS-NMPs. Liver inflammation was mainly increased in chronic exposure to 80 nm and 0.5 µm PS-NMPs. Liver lipid deposition was significantly enhanced after PS-NMPs exposure. However, oxidative stress was not changed under PS-NMPs exposure. GO enrichment and KEGG pathway analyses revealed that the DEGs and shared DEGs were mainly enriched in the metabolism of lipids. The mRNA expression levels of genes related to fatty acid oxidation, synthesis and transport were dramatically induced by PS-NMPs exposure. Four hub genes, Acot3, Abcc3, Nr1i3 and Fmo2, were identified by CytoHubba analysis of shared DEGs. The mRNA expression levels of three hub genes, Acot3, Abcc3 and Nr1i3, were significantly augmented under chronic PS-NMPs exposure. Our results suggest that Acot3, Abcc3 and Nr1i3 are potential molecules involved in the development of liver fibrosis under chronic exposure to PS-NMPs.

Macronutrient modulation in metabolic dysfunction-associated steatotic liver disease - the molecular role of fatty acids versus sugars in human metabolism and disease progression.

Metabolic dysfunction-associated steatotic liver disease (MASLD) is a significant public health concern, with its progression to metabolic dysfunction-associated steatohepatitis (MASH) and fibrosis leading to severe outcomes including cirrhosis, hepatocellular carcinoma and liver failure. While obesity and excess energy intake are well established contributors to the development and progression of MASLD, the distinct role of specific macronutrients is less clear. This review examines the mechanistic pathways through which dietary fatty acids and sugars contribute the development of hepatic inflammation and fibrosis, offering a nuanced understanding of their respective roles in MASLD progression. In terms of addressing potential therapeutic options, human intervention studies that investigate whether modifying the intake of dietary fats and carbohydrates affects MASLD progression are reviewed. By integrating this evidence, this review seeks to bridge the gap in the understanding between the mechanisms of macronutrient-driven MASLD progression and the effect of altering the intake of these nutrients in the clinical setting, and presents a foundation for future research into targeted dietary strategies for the treatment of the disease.

Huangqi-Danshen decoction alleviates renal fibrosis through targeting SCD1 to modulate cGAS/STING signaling.

The Huangqi-Danshen decoction (HDD) is composed of Huangqi (Astragali Radix) and Danshen (Salviae Miltiorrhizae Radix et Rhizoma) and has been shown to alleviate renal fibrosis. However, the potential therapeutic mechanisms and effective components of HDD remain unclear. Both lipid metabolism and cGAS/STING signaling play vital roles in the development and progression of renal fibrosis. However, their relationship in renal fibrosis is largely unknown. The present study aimed to investigate the antifibrotic mechanisms of HDD from the perspective of lipid remodeling and cGAS/STING signaling. In vivo, renal fibrosis was induced by feeding male C57BL/6 mice with 0.2% adenine-diet for 28 consecutive days. The treatment groups were orally administered HDD at low, medium, and high doses of 3.4g/kg/d, 6.8g/kg/d, and 13.6g/kg/d simultaneously with modeling. Renal function was evaluated by the serum levels of urea nitrogen and creatinine, pathological changes of renal tissue were evaluated by Periodic acid-Schiff and Masson's trichrome staining, and renal lipid metabolites were analyzed by lipidomics. Western blotting, immunohistochemistry, and immunofluorescence were used to detect the expressions of fibrosis-related proteins, SCD1, and cGAS/STING signaling-related proteins in renal tissue. In vitro, mouse primary proximal tubular epithelial cells (PTECs) were treated with transforming growth factor-β1 (TGF-β1) or stearoyl-CoA desaturase 1 (SCD1) inhibitor A939572. Additionally, UHPLC-QE-MS analysis and TCMSP database were used to screen the effective components of HDD, and the action mechanisms of these components were verified in mouse primary PTECs. HDD dose-dependently improved renal function, pathological injury, and fibrosis in adenine-induced chronic kidney disease (CKD) mice model. Moreover, cGAS/STING signaling was significantly activated in fibrotic kidney and was suppressed by HDD treatment. In renal lipidomics analysis, 521 and 138 differential lipids were identified in control vs. CKD and CKD vs. CKD+HDD, respectively. Of note, lipids increased in fibrotic kidneys were more saturated (fewer double bonds), whereas lipids increased by HDD were less saturated (more double bonds). Further, SCD1 expression was significantly down-regulated in fibrotic kidney and could be restored by HDD treatment. The expression of SCD1 was also down-regulated in Ju CKD patients' dataset and TGF-β1-induced fibrogenic responses in mouse primary PTECs. Mechanistically, specific inhibition of SCD1 expression could activate cGAS/STING signaling in primary PTECs. In addition, three components of HDD (isoimperatorin, baicalin, and miltirone) were screened out. Furthermore, administration of these three components, especially isoimperatorin and miltirone, counteracted the activation of cGAS/STING signaling induced by SCD1 pharmacological inhibition. HDD could alleviate renal fibrosis, which may be related to the regulation of cGAS/STING signaling through targeting SCD1.

CD131 antagonism blocks inflammation, emphysema and fibrosis in an asthma-COPD overlap mouse model originating in early life.

Asthma-COPD overlap (ACO) is characterized by patients exhibiting features of both asthma and COPD. Currently, there is no specific treatment for ACO. This study aimed to investigate the therapeutic potential of targeting CD131, a shared receptor subunit for IL-3, IL-5 and GM-CSF, in ACO development and in preventing acute viral exacerbations. A two-hit mouse model of ACO was established by house dust mite (HDM) allergen sensitization to model asthma, and elastase treatment to model emphysema. In a separate model, human rhinovirus 1b (RV1b) was used to induce an acute asthma exacerbation. A neutralizing antibody against CD131 was used to block CD131 in vivo signalling. Mice exposed to HDM and elastase developed cardinal features for asthma and COPD, including airway hyperreactivity (AHR) and emphysema. A mixed granulocytic inflammatory profile was identified in the lungs, including expansion of monocyte-derived macrophages, neutrophils and eosinophils. RT-qPCR analysis detected heightened gene expression of Mmp12, Il5 and Il13. Transcriptomic analysis further revealed pathway enrichment for type 2 inflammation and macrophage activation. Blockade of CD131 effectively reduced the lung inflammation and prevented the development of AHR, airway fibrosis and emphysema. Interestingly, pathway enrichment for Th1 response and interferon production detected in the model was not affected by the treatment. Consistently, CD131 antagonism prevented RV1b-induced asthma exacerbation without compromising RV1b clearance. CD131 signalling coordinates multiple pathological pathways that drive airway inflammation and lung remodelling in ACO. Hence, CD131 antagonism represents a novel approach to combating the immunopathology in the complex ACO setting.

Cardiac fatty acid binding protein as a biomarker for long-term prognosis of clinically manifested heart failure and severe post-infarction left ventricular myocardial remodeling

The aim of the study is to evaluate cardiac fatty acid binding protein as a prognostic biomarker for the occurrence of severe post-infarction structural and functional remodeling of the left ventricular myocardium and heart failure with clinical manifestations in patients with acute myocardial infarction during long-term follow-up. Material and methods. The study included 95 patients with acute myocardial infarction and ST-segment elevation (mean age 56.8 ± 9.8 years). Upon admission to the emergency room, all patients underwent clinical and laboratory studies to determine cardiac fatty acid binding protein (cFABP) and high-sensitivity troponin T (hs-TnT). At the end of the long-term follow-up (Me = 36 months), the patients were examined for clinically evident heart failure (NYHA functional class II and higher), high-sensitivity C-reactive protein (hsCRP) was determined in the blood, and echocardiography was performed. According to the echocardiography data, the presence and severity of structural and functional remodeling of the left ventricle myocardium (SFR LV) were established. Results. It was determined that the presence of clinically evident heart failure is directly associated with age, the Charlton comorbidity index, cFABP ≥10 ng/ml upon admission to the hospital and has a direct tendency to be associated with hs-TnT upon admission to the hospital. The presence of severe structural and functional remodeling of the left ventricle myocardium is directly associated with age, obesity, creatinine, cFABP ≥ 10 ng/ml and hs-TnT upon admission to hospital, and there is also a direct tendency towards an association with age. It was revealed that hs-TnT upon admission to hospital is directly associated with hsCRP ≥ 2 mg/l at the end of long-term followup. Conclusions. the presence of cFABP ≥ 10 ng/ml in the blood of patients with acute myocardial infarction upon admission to hospital is associated with an increase in the probability of developing clinically evident heart failure during long-term follow-up by 4.27 times, and severe structural and functional remodeling of the left ventricle myocardium is 3.07 times more likely, which is due to the size of the infarction lesion and the subsequent development of myocardial fibrosis.

Lactate accumulation promotes immunosuppression and fibrotic transformation of bone marrow microenvironment in myelofibrosis

BackgroundClonal myeloproliferation and fibrotic transformation of the bone marrow (BM) are the pathogenetic events most commonly occurring in myelofibrosis (MF). There is great evidence indicating that tumor microenvironment is characterized by high lactate levels, acting not only as an energetic source, but also as a signaling molecule.MethodsTo test the involvement of lactate in MF milieu transformation, we measured its levels in MF patients’ sera, eventually finding a massive accumulation of this metabolite, which we showed to promote the expansion of immunosuppressive subsets. Therefore, to assess the significance of its trafficking, we inhibited monocarboxylate transporter 1 (MCT1) by its selective antagonist, AZD3965, eventually finding a mitigation of lactate-mediated immunosuppressive subsets expansion. To further dig into the impact of lactate in tumor microenvironment, we evaluated the effect of this metabolite on mesenchymal stromal cells (MSCs) reprogramming.ResultsOur results show an activation of a cancer-associated phenotype (CAF) related to mineralized matrix formation and early fibrosis development. Strikingly, MF serum, enriched in lactate, causes a strong deposition of collagen in healthy stromal cells, which was restrained by AZD3965. To corroborate these outcomes, we therefore generated for the first time a TPOhigh zebrafish model for the establishment of experimental fibrosis. By adopting this model, we were able to unveil a remarkable increase in lactate concentration and monocarboxylate transporter 1 (MCT1) expression in the site of hematopoiesis, associated with a strong downregulation of lactate export channel MCT4. Notably, exploiting MCTs expression in biopsy specimens from patients with myeloproliferative neoplasms, we found a loss of MCT4 expression in PMF, corroborating changes in MCT expression during BM fibrosis establishment.ConclusionsIn conclusion, our results unveil lactate as a key regulator of immune escape and BM fibrotic transformation in MF patients, suggesting MCT1 blocking as a novel antifibrotic strategy.