Excessive Extracellular Matrix Deposition Research Articles

Co-Mn Complex Oxide Nanoparticles as Potential Reactive Oxygen Species Scavenging Agents for Pulmonary Fibrosis Treatment

Idiopathic pulmonary fibrosis (IPF) is a chronic and age-related lung disease that has few treatment options. Reactive oxygen species (ROS) play an important role in the introduction and development of IPF. In the present study, we developed multifunctional Cobalt (Co)–Manganese (Mn) complex oxide nanoparticles (Co-MnNPs), which can scavenge multiple types of ROS. Benefiting from ROS scavenging activities and good biosafety, Co-MnNPs can suppress canonical and non-canonical TGF-β pathways and, thus, inhibit the activation of fibroblasts and the productions of extracellular matrix. Furthermore, the scavenging of ROS by Co-MnNPs reduce the LPS-induced expressions of pro-inflammatory factors in macrophages, by suppressing NF-κB signaling pathway. Therefore, Co-MnNPs can reduce the excessive extracellular matrix deposition and inflammatory responses in lungs and, thus, alleviate pulmonary fibrosis induced by bleomycin (BLM) in mice. Taken together, this work offers an anti-fibrotic agent for treatment of IPF and other ROS-related diseases.

Adipose-derived mesenchymal stem cells inhibit hepatic stellate cells activation to alleviate liver fibrosis via Hippo pathway

BackgroundLiver fibrosis is a common pathological process of chronic liver disease, characterized by excessive deposition of extracellular matrix (ECM). Mesenchymal stem cells (MSCs) have been found to have potential therapy effect on liver fibrosis, but the mechanism involved was still unclear. The objective of this study is to investigate the therapeutic efficacy of adipose-derived mesenchymal stem cells (ADMSCs) on the treatment of liver fibrosis, with particular emphasis on elucidating the underlying mechanism of action through which ADMSCs inhibit the activation of hepatic stellate cells (HSCs).MethodsADMSCs were isolated from adipose tissue and injected intravenously into hepatic fibrosis model of rats. The histopathological changes, liver function, collagen deposition, the expression of fibroin and Hippo pathway were evaluated. In vitro, ADMSCs were co-cultured with HSCs activated by transforming growth factor beta 1 (TGF-β1), and the inhibitor of Hippo pathway was used to evaluate the therapeutic mechanism of ADMSCs transplantation.ResultsThe results showed that after the transplantation of ADMSCs, the liver function of rats was improved, the degree of liver fibrosis and collagen deposition were reduced, and the Hippo signaling pathway was activated. In vitro, ADMSCs can effectively inhibit the proliferation and activation of HSCs induced by TGF-β1 treatment. However, the inhibitory effect of ADMSCs was weakened after blocking the Hippo signaling pathway.ConclusionsADMSCs inhibit HSCs activation by regulating YAP/TAZ, thereby promoting functional recovery after liver fibrosis. These findings lay a foundation for further investigation into the precise mechanism by which ADMSCs alleviate liver fibrosis.

Evaluation of Cross-Linked Actin Networks (CLANs) in Human Trabecular Meshwork Cells and Tissues.

Elevated intraocular pressure (IOP) is a major risk factor for the development and progression of glaucoma, the leading cause of irreversible vision loss and blindness. An overall increase in resistance to aqueous humor outflow causes sustained elevation in IOP. Glaucomatous insults in the aqueous humor outflow pathway, including the trabecular meshwork (TM), precede such chronic physiological changes in IOP. These insults include ultrastructural changes with excessive extracellular matrix deposition and actin cytoskeletal reorganization that leads to pathological stiffening of the ocular tissues. One of the most common cytoskeletal changes associated with TM tissue stiffness in glaucoma is the increased prevalence of cross-linked actin networks (CLANs) in cells of the trabecular meshwork (TM) and lamina cribrosa (LC). In glaucomatous cells, rearrangement of linear actin stress fibers leads to formation of polygonal arrays within the cytoplasm, resembling a geodesic dome-like structure, that we identified as CLANs. In addition to increased amounts of CLANs in POAG TM cells and tissues, we also discovered that glucocorticoid (GC) and TGFβ2 signaling pathways associated with the development of ocular hypertension (OHT) and glaucoma also induced CLANs in the TM. Despite a clear association, we are yet to completely understand the mechanisms involved in CLAN formation and their direct relevance to disease pathology. In this chapter, we will describe methods to identify and characterize CLANs using fluorescent microscopy in primary TM cell cultures, ex vivo perfusion cultured human anterior segments, and in situ in human donor eyes.

Mouse Model of Glucocorticoid-Induced Glaucoma.

Extended glucocorticoid (GC) treatment can lead to ocular hypertension and induce iatrogenic open-angle glaucoma. GC-induced glaucoma mimics many clinical and pathological features of primary open-angle glaucoma (POAG), and therefore mouse models of GC-induced glaucoma are utilized to study pathophysiology of glaucoma. We have recently demonstrated that weekly periocular injections of dexamethasone-21-acetate (Dex-Ac) lead to robust and significant intraocular pressure (IOP) elevation, retinal ganglion cell (RGC) loss, and optic nerve degeneration in mice. Our mouse model exhibits signature features of POAG including significant IOP elevation due to reduced outflow facility, progressive optic nerve degeneration, and structural and functional loss of RGCs. Dex-induced IOP elevation is associated with increased aqueous outflow resistance due to trabecular meshwork (TM) dysfunction including excessive extracellular matrix deposition and induction of endoplasmic reticulum stress. Mouse model of Dex-induced glaucoma represents an ideal animal model to investigate both glaucomatous damage to the TM and RGC axons and to develop novel therapies. Here, we present a detailed protocol for developing this model in laboratory settings.

Recent advances of nanomaterials in imaging liver fibrosis

AbstractLiver fibrosis is a pathological process resulting from prolonged exposure to various injury factors. It is characterized by the abnormal proliferation and activation of hepatic stellate cells and excessive deposition of extracellular matrix. If left untreated, it can progress to cirrhosis, liver failure, and even liver cancer. There is currently no efficient and accurate clinical diagnostic method for early liver fibrosis. Therefore, there is an urgent need to address the challenge of accurate staging and early diagnosis of liver fibrosis in clinical practice. Recently, nanomaterials have demonstrated significant potential for enhancing the diagnosis of liver fibrosis. Nanomaterials possess the ability to precisely identify and target the microenvironment associated with liver fibrosis. By enhancing their enrichment in the target area, nanomaterials can improve imaging contrast of fibrosis lesions in the liver, thereby enabling accurate diagnosis of liver fibrosis. Accordingly, this review delves into the latest research and advancements concerning nanomaterials in liver fibrosis diagnosis.

Renal microRNA-144-3p is associated with transforming growth factor-β1-induced oxidative stress and fibrosis by suppressing the NRF2 pathway in hypertensive diabetic kidney disease

Chronic kidney disease (CKD) is a global health problem characterized by progressive renal fibrosis and excessive extracellular matrix deposition. Oxidative stress and epigenetic regulation, particularly through microRNAs (miRNAs), play crucial roles in the pathogenesis of CKD. In this study, we investigated the role of urinary miR-144-3p, which is upregulated in rats with CKD induced by diabetes and hypertension, in renal fibrosis progression, particularly its regulation of the nuclear factor erythroid-2-related factor 2 (NRF2) pathway. Our findings revealed elevated miR-144-3p levels and reduced NRF2 and target gene levels in kidney tissues of streptozotocin-treated spontaneously hypertensive rats. In vitro experiments demonstrated that miR-144-3p directly binds to the 3'-untranslated region of nrf2, suppressing the NRF2 pathway in renal tubular epithelial cells. Additionally, the profibrogenic factor transforming growth factor (TGF)-β1 increased miR-144-3p expression. TGF-β1-induced NRF2 suppression and reactive oxygen species elevation were found to be mediated through miR-144-3p upregulation. In vivo, cilostazol, an antiplatelet drug with an NRF2-activating effect, ameliorated renal injury in diabetic hypertensive rats by decreasing TGF-β1 and miR-144-3p levels while increasing NRF2 and its target gene levels in the kidneys. These findings highlight the potential therapeutic value of targeting the miR-144-3p/NRF2 pathway to attenuate CKD progression in hypertensive diabetic conditions.

Revisiting the role of MicroRNAs in the pathogenesis of idiopathic pulmonary fibrosis.

Idiopathic pulmonary fibrosis (IPF) is a prevalent chronic pulmonary fibrosis disease characterized by alveolar epithelial cell damage, fibroblast proliferation and activation, excessive extracellular matrix deposition, and abnormal epithelial-mesenchymal transition (EMT), resulting in tissue remodeling and irreversible structural distortion. The mortality rate of IPF is very high, with a median survival time of 2-3years after diagnosis. The exact cause of IPF remains unknown, but increasing evidence supports the central role of epigenetic changes, particularly microRNA (miRNA), in IPF. Approximately 10% of miRNAs in IPF lung tissue exhibit differential expression compared to normal lung tissue. Diverse miRNA phenotypes exert either a pro-fibrotic or anti-fibrotic influence on the progression of IPF. In the context of IPF, epigenetic factors such as DNA methylation and long non-coding RNAs (lncRNAs) regulate differentially expressed miRNAs, which in turn modulate various signaling pathways implicated in this process, including transforming growth factor-β1 (TGF-β1)/Smad, mitogen-activated protein kinase (MAPK), and phosphatidylinositol-3-kinase/protein kinase B (PI3K/AKT) pathways. Therefore, this review presents the epidemiology of IPF, discusses the multifaceted regulatory roles of miRNAs in IPF, and explores the impact of miRNAs on IPF through various pathways, particularly the TGF-β1/Smad pathway and its constituent structures. Consequently, we investigate the potential for targeting miRNAs as a treatment for IPF, thereby contributing to advancements in IPF research.

SUMO: A new perspective to decipher fibrosis.

Fibrosis is characterized by excessive extracellular matrix (ECM) deposition resulting from dysregulated wound healing and connective tissue repair mechanisms. Excessive accumulation of ECM leads to fibrous tissue formation, impairing organ function and driving the progression of various fibrotic diseases. Recently, the role of small ubiquitin-like modifiers (SUMO) in fibrotic diseases has attracted significant attention. SUMO-mediated SUMOylation, a highly conserved posttranslational modification, participates in a variety of biological processes, including nuclear-cytosolic transport, cell cycle progression, DNA damage repair, and cellular metabolism. Conversely, SUMO-specific proteases cleave the isopeptide bond of SUMO conjugates, thereby regulating the deSUMOylation process. Mounting evidence indicates that SUMOylation and deSUMOylation regulate the functions of several proteins, such as Smad3, NF-κB, and promyelocytic leukemia protein, which are implicated in fibrotic diseases like liver fibrosis, myocardial fibrosis, and pulmonary fibrosis. This review summarizes the role of SUMO in fibrosis-related pathways and explores its pathological relevance in various fibrotic diseases. All evidence suggest that the SUMO pathway is important targets for the development of treatments for fibrotic diseases.

Emerging Roles of Ketone Bodies in Cardiac Fibrosis.

Cardiac fibrosis, characterized by excessive extracellular matrix (ECM) deposition within the myocardium, poses a significant challenge in cardiovascular health, contributing to various cardiac pathologies. Ketone bodies (KBs), particularly β-hydroxybutyrate (β-OHB), have emerged as subjects of interest due to their potential cardioprotective effects. However, their specific influence on cardiac fibrosis remains underexplored. This literature review comprehensively examines the relationship between KBs and cardiac fibrosis, elucidating potential mechanisms through which KBs modulate fibrotic pathways. A multifaceted interplay exists between KBs and key mediators of cardiac fibrosis. While some studies indicate a pro-fibrotic role for KBs, others highlight their potential to attenuate fibrosis and cardiac remodeling. Mechanistically, KBs may regulate fibrotic pathways through modulation of cellular components such as cardiac fibroblasts, macrophages, and lymphocytes, as well as extracellular matrix proteins. Furthermore, the impact of KBs on cellular processes implicated in fibrosis, including oxidative stress, chemokine and cytokine expression, caspase activation, and inflammasome signaling are explored. While conflicting findings exist regarding the effects of KBs on these processes, emerging evidence suggests a predominantly beneficial role in mitigating inflammation and oxidative stress associated with fibrotic remodeling. Overall, this review underscores the importance of elucidating the complex interplay between KB metabolism and cardiac fibrosis. Insights gained have the potential to inform novel therapeutic strategies for managing cardiac fibrosis and associated cardiovascular disorders, highlighting the need for further research in this area.

Characterization of regeneration initiating cells during Xenopus laevis tail regeneration

BackgroundEmbryos are regeneration and wound healing masters. They rapidly close wounds and scarlessly remodel and regenerate injured tissue. Regeneration has been extensively studied in many animal models using new tools such as single-cell analysis. However, until now, they have been based primarily on experiments assessing from 1 day post injury.ResultsIn this paper, we reveal that critical steps initiating regeneration occur within hours after injury. We discovered the regeneration initiating cells (RICs) using single-cell and spatial transcriptomics of the regenerating Xenopus laevis tail. RICs are formed transiently from the basal epidermal cells, and their expression signature suggests they are important for modifying the surrounding extracellular matrix thus regulating development. The absence or deregulation of RICs leads to excessive extracellular matrix deposition and defective regeneration.ConclusionRICs represent a newly discovered transient cell state involved in the initiation of the regeneration process.

Rutaecarpine alleviates inflammation and fibrosis by targeting CK2α in diabetic nephropathy

Diabetic nephropathy (DN) is one of the serious microvascular complications of diabetes mellitus. During the progression of DN, the proliferation of glomerular mesangial cells (GMCs) leads to the deposition of excessive extracellular matrix (ECM) in the mesangial region, eventually resulting in glomerulosclerosis. Rutaecarpine (Rut), an alkaloid found in the traditional Chinese medicinal herb Fructus Evodiae (Euodia rutaecarpa (Juss.) Benth.), has many biological activities. However, its mechanism of action in DN remains unknown. This study used db/db mice and high glucose (HG)-treated mouse mesangial cells (SV40 MES-13) to evaluate the protective effects of Rut and underlying mechanisms on GMCs in DN. We found that Rut alleviated urinary albumin and renal function and significantly relieved renal pathological damage. In addition, Rut decreased the ECM production, and renal inflammation and suppressed the activation of TGF-β1/Smad3 and NF-κB signaling pathways in vitro and in vivo. Protein kinase CK2α (CK2α) was identified as the target of Rut by target prediction, molecular docking, and cellular thermal shift assay (CETSA), and surface plasmon resonance (SPR). Furthermore, Rut could not continue to play a protective role in HG-treated SV40 cells after silencing CK2α. In summary, this study is the first to find that Rut can suppress ECM production and inflammation in HG-treated SV40 cells by inhibiting the activation of TGF-β1/Smad3 and NF-κB signaling pathways and targeting CK2α. Thus, Rut can potentially become a novel treatment option for DN.

The involvement of HDAC3 in the pathogenesis of lung injury and pulmonary fibrosis.

Acute lung injury (ALI) and its severe counterpart, acute respiratory distress syndrome (ARDS), are critical respiratory conditions with high mortality rates due primarily to acute and intense pulmonary inflammation. Despite significant research advances, effective pharmacological treatments for ALI and ARDS remain unavailable, highlighting an urgent need for therapeutic innovation. Notably, idiopathic pulmonary fibrosis (IPF) is a chronic, progressive disease characterized by the irreversible progression of fibrosis, which is initiated by repeated damage to the alveolar epithelium and leads to excessive extracellular matrix deposition. This condition is further complicated by dysregulated tissue repair and fibroblast dysfunction, exacerbating tissue remodeling processes and promoting progression to terminal pulmonary fibrosis. Similar to that noted for ALI and ARDS, treatment options for IPF are currently limited, with no specific drug therapy providing a cure. Histone deacetylase 3 (HDAC3), a notable member of the HDAC family with four splice variants (HD3α, -β, -γ, and -δ), plays multiple roles. HDAC3 regulates gene transcription through histone acetylation and adjusts nonhistone proteins posttranslationally, affecting certain mitochondrial and cytoplasmic proteins. Given its unique structure, HDAC3 impacts various physiological processes, such as inflammation, apoptosis, mitochondrial homeostasis, and macrophage polarization. This article explores the intricate role of HDAC3 in ALI/ARDS and IPF and evaluates its therapeutic potential the treatment of these severe pulmonary conditions.

YAP/TAZ Signaling in the Pathobiology of Pulmonary Fibrosis.

Pulmonary fibrosis (PF) is a severe, irreversible lung disease characterized by progressive scarring, with idiopathic pulmonary fibrosis (IPF) being the most prevalent form. IPF's pathogenesis involves repetitive lung epithelial injury leading to fibroblast activation and excessive extracellular matrix (ECM) deposition. The prognosis for IPF is poor, with limited therapeutic options like nintedanib and pirfenidone offering only modest benefits. Emerging research highlights the dysregulation of the yes-associated protein (YAP)/transcriptional coactivator with PDZ-binding motif (TAZ) signaling pathway as a critical factor in PF. YAP and TAZ, components of the Hippo pathway, play significant roles in cell proliferation, differentiation, and fibrosis by modulating gene expression through interactions with TEA domain (TEAD) transcription factors. The aberrant activation of YAP/TAZ in lung tissue promotes fibroblast activation and ECM accumulation. Targeting the YAP/TAZ pathway offers a promising therapeutic avenue. Preclinical studies have identified potential treatments, such as trigonelline, dopamine receptor D1 (DRD1) agonists, and statins, which inhibit YAP/TAZ activity and demonstrate antifibrotic effects. These findings underscore the importance of YAP/TAZ in PF pathogenesis and the potential of novel therapies aimed at this pathway, suggesting a new direction for improving IPF treatment outcomes. Further research is needed to validate these approaches and translate them into clinical practice.

SP6.7 - Exploring the Mechanistic Basis of the Adipose Derived Stem Cell Secretome on Extracellular Matrix Remodelling in Radiation Induced Fibrosis

Abstract Background Radiation-induced fibrosis (RIF) is a debilitating complication following radiotherapy, characterised by fibroblast proliferation and excessive extracellular matrix (ECM) deposition, leading to functional and aesthetic impairments. Although autologous fat grafting (AFG) has shown promise in reversing RIF, the mechanisms, largely attributed to adipose-derived stem cells (ADSCs), remain elusive. This study aimed to investigate ADSCs’ and their secretome on ECM remodelling in RIF management. Methods The anti-fibrotic potential of the ADSC secretome on HDFs subjected to ionising radiation was assessed via a series of in vitro experiments. Control HDFs were compared with irradiated HDFs to assess any phenotypical changes. Irradiated HDFs were treated with ADSC pre-conditioned media (CM) or ADSC co-culture (CC). Gene expression (COL1A1, TGF-β1, CCN-2, MMP-1, MMP-3, TIMP-1, ACTA2, TNC) was assessed via real-time quantitative PCR (RT-qPCR). ProCollagen1a1 and CCN2 protein concentrations were assessed by ELISA. Results Irradiated HDFs demonstrated changes in fibrotic gene expression. ADSC-CM treatment significantly reduced COL1A1 expression, although protein levels remained unchanged. TGF-β1, CCN2, MMP-3, TIMP-1 and ACTA-2 exhibited reduced expression post-ADSC-CM treatment whereas TNC expression was found to be significantly increased. Co-culture with ADSCs led to a general, but not statistically significant, decrease in pro-fibrotic gene expression. Notably, CCN-2 protein expression significantly increased. Conclusion This study demonstrates that ionising radiation results in a pathological pro-fibrotic phenotype in HDFs. The ADSC secretome potentially mitigates this, reducing pro-fibrotic gene expression. Unexpectedly, co-culture experiments highlighted a complex interaction with upregulation of fibrosis-associated genes. Further research is needed to clarify these interactions to improve therapeutic interventions for RIF.

The role of apoptosis, immunogenic cell death, and macrophage polarization in carbon ion radiotherapy for keloids: Targeting the TGF-β1/SMADs signaling pathway

Keloids, characterized by excessive extracellular matrix (ECM) deposition and aberrant fibrous tissue proliferation, present significant therapeutic challenges due to their recalcitrant and recurrent nature. This study explores the efficacy of Carbon Ion Radiotherapy (CIRT) as a novel therapeutic approach for keloids, focusing on its impact on fibroblast proliferation, apoptosis induction, immunogenic cell death (ICD), macrophage polarization, and the TGF-β/SMAD signaling pathway. Utilizing a murine model of keloid formed by subcutaneous injection of zeocin in C57BL/6 mice, we demonstrated that CIRT effectively reduces collagenous fiber synthesis and collagen production in keloid tissues. Further, CIRT was shown to inhibit keloid fibroblast proliferation and to induce apoptosis, as evidenced by increased expression of apoptosis-related proteins and confirmed through flow cytometry and TUNEL assay. Notably, CIRT induced mitochondrial stress, leading to enhanced immunogenicity of cell death, characterized by increased expression of ICD markers and secretion of interferon-γ. Additionally, CIRT promoted a shift from M2 to M1 macrophage polarization, potentially reducing TGF-β release and mitigating ECM deposition. Our findings suggest that CIRT mediates its therapeutic effects through the inhibition of the TGF-β/SMAD signaling pathway, thereby attenuating ECM formation and offering a promising avenue for keloid treatment. This study underscores the potential of CIRT as an innovative strategy for managing keloids, highlighting its multifaceted impact on key cellular processes involved in keloid pathogenesis.

Rapid detection of guttae area using aniline blue staining in Fuchs endothelial corneal dystrophy mouse model.

Fuchs endothelial corneal dystrophy (FECD) is a leading cause of corneal endothelial degeneration resulting in impaired visual acuity. Excessive deposition of extracellular matrix (guttae) on Descemet's membrane (DM) is the hallmark of FECD. We sought to detect the guttae area rapidly using aniline blue (AB) staining in FECD mouse model. FECD mouse model was established via ultraviolet A (UVA) exposure. Masson's trichrome staining was utilized to stain the corneal sections. AB staining was utilized to stain both whole cornea tissues and stripped Descemet's membrane-endothelium complex (DMEC) flat mounts, while immunofluorescence staining of collagen I was employed to stain guttae areas. In Masson's trichrome staining, corneal collagen fibrils were stained blue with AB. The DMEC flat mounts were stained into relative dark blue areas and relative light blue areas using 2% AB staining. The areas of dark blue could almost overlap with collagen I-positive areas, and have an acellular centre and a moderately distinct boundary line with the surrounding corneal endothelial cells. In conclusion, AB staining is a rapid and effective method for the evaluation of the guttae areas in the FECD mouse model.

FGF21 Ameliorates Fibroblasts Activation and Systemic Sclerosis by Inhibiting CK2α/GLI2 Signaling Axis

Systemic sclerosis is a typical fibrotic disease of unknown etiology that is characterized by abnormal fibroblast activation and excessive deposition of extracellular matrix. Unfortunately, effective therapeutic approaches are lacking. FGF21 plays a key role in mediating a variety of biological activities. However, its specific function in systemic sclerosis is unclear. In this study, we found that the expression of FGF21 was significantly downregulated in fibrotic skin tissue and in TGF-β-stimulated fibroblasts. Furthermore, our studies demonstrated that treatment with recombinant FGF21 in the skin significantly alleviated bleomycin-induced and TBRI-activated fibrosis and inhibited the activation of fibroblasts, whereas skin fibrosis was exacerbated by deletion of FGF21. Mechanistically, FGF21 inhibits the activity of CK2α and promotes the degradation of GLI2. In conclusion, these results indicate that FGF21 attenuates skin fibrosis through the CK2α/GLI2 signaling pathway and therefore may be a potential therapeutic target for systemic sclerosis.

Abstract P355: Multiomic Analyses Reveal Sex-specific Mechanisms Governing Cardiac Fibrosis.

Cardiac fibrosis—the deposition of excess extracellular matrix in the heart—occurs during pathological cardiac remodelling and precedes cardiac dysfunction and heart failure. Experimental and clinical data show that both cardiac fibrosis and heart failure exhibit sex-specific differences, particularly in the absence of ischemic injury. However, no study to date has systematically examined this, or the hormonal mechanisms driving these differences, using high-resolution single-cell and spatial omics. To address this gap, we applied single-cell and spatial omics to map the quality and distribution of non-ischemic cardiac fibrosis in human and mouse hearts. Further, to query the impact of sex hormones on cardiac fibrosis development, we analysed hearts of castrated (CAST) and ovariectomized (OVX) mice, which were ectopically infused with angiotensin-II (AngII). Using single cell transcriptomic data of hypertensive mouse hearts, we identified a fibroblast population driving cardiac fibrosis with a unique gene signature. We confirmed the presence of these cells in multiple mouse models and aged donor human hearts. Spatial mapping of fibrosis showed a sex-specific distribution of fibrosis, specifically in the development of perivascular fibrosis in the heart. Hypertensive male mice exhibited extensive perivascular fibrosis, and coronary artery adventitial hypertrophy, which was absent in females. However, OVX resulted in the development of perivascular fibrosis in hypertensive mice suggesting a cardioprotective role of estrogen. Confirming these observations, spatial transcriptomic analyses showed distinct fibrotic signatures driving perivascular and interstitial fibrosis, and transcriptomic differences between females and males. Our findings provide fundamental new insights towards the importance of biological sex in driving cardiac fibrosis, pointing to new mechanisms that may be manipulated to ameliorate development of heart failure.

Hepatic stellate cell single cell atlas reveals a highly similar activation process across liver disease aetiologies

Background & AimsThe progression of chronic liver disease (CLD) is characterized by excessive extracellular matrix deposition, disrupting hepatic architecture and function. Upon liver injury, hepatic stellate cells (HSCs) differentiate towards myofibroblasts and become inflammatory, proliferative and fibrogenic. To date it is still unclear whether HSC activation is driven by similar mechanisms in different aetiologies. MethodsHSCs from multiple publicly available single-cell RNA-sequencing datasets were annotated and merged into a single-cell HSC activation atlas. Spheroid co-cultures of primary mouse hepatocytes/HSCs (n=5) and ELISAs on patient plasma samples (n=80) were performed to validate the mechanistic insight obtained from the HSC atlas. ResultsWe established an HSC activation atlas in which HSCs are clearly divided into 3 distinct transcriptomic profiles: quiescent HSCs, initiatory HSCs and myofibroblasts. These transcriptomic profiles are present in each of the investigated mouse liver injury models as well as in human chronic liver diseases, indicating that HSC activation is a conserved process. This activation process is driven by a core set of transcription factors independent of liver injury or species. Furthermore, we reveal novel ligands associated with activation of HSCs in multiple liver injury models and validate the profibrotic effect of parathyroid hormone. Finally, we identify COLEC10 as a conserved marker for quiescent HSCs and a biomarker of liver fibrosis in patients with different CLDs (p<0.0001). ConclusionsWe reveal unexpected similarities in the regulatory mechanisms of HSCs across diverse liver injury settings and species. The HSC activation atlas has the potential to provide novel insights into liver fibrosis and steer novel treatment options. Impact and implicationsThis study establishes a single-cell atlas of hepatic stellate cells across various liver injuries, highlighting a conserved activation process between different injuries and across species. The discovery of novel activating ligands and the biomarker COLEC10 in human plasma enhances diagnostic and therapeutic strategies. Additionally, the conserved activation process supports the use of any mouse model for mechanistic studies and testing of new anti-fibrotic compounds, streamlining preclinical research efforts.

The Effects of Mesenchymal Stem Cells-Derived Exosomes on Metabolic Reprogramming in Scar Formation and Wound Healing.

Pathological scarring results from aberrant cutaneous wound healing due to the overactivation of biological behaviors of human skin fibroblasts, characterized by local inordinate inflammation, excessive extracellular matrix and collagen deposition. Yet, its underlying pathogenesis opinions vary, which could be caused by increased local mechanical tension, enhanced and continuous inflammation, gene mutation, as well as cellular metabolic disorder, etc. Metabolic reprogramming is the process by which the metabolic pattern of cells undergoes a systematic adjustment and transformation to adapt to the changes of the external environment and meet the needs of their growth and differentiation. Therefore, the abnormality of metabolic reprogramming in cells within wounds and scars attaches great importance to scar formation. Mesenchymal stem cells-derived exosomes (MSC-Exo) are the extracellular vesicles that play an important role in tissue repair, cancer treatment as well as immune and metabolic regulation. However, there is not a systematic work to detail the relevant studies. Herein, we gave a comprehensive summary of the existing research on three main metabolisms, including glycometabolism, lipid metabolism and amino acid metabolism, and MSC-Exo regulating metabolic reprogramming in wound healing and scar formation for further research reference.