Abnormal Extracellular Matrix Research Articles

Plasma collagen neoepitopes are associated with multiorgan disease in the ACCESS and GRADS sarcoidosis cohorts

IntroductionThe pathogenesis of sarcoidosis involves tissue remodelling mediated by the accumulation of abnormal extracellular matrix, which is partly the result of an imbalance in collagen synthesis, cross-linking and degradation. During...

Abstract 4137424: Circulating Levels of the Pro-Fibrotic Collagen Hormone Endotrophin are Associated with the Risk of Experiencing Major Adverse Cardiovascular Events in Individuals with Type 2 Diabetes – The Thousand&2 Study

Introduction: Cardiovascular disease (CVD) complications are the leading cause of mortality in individuals with type 2 diabetes (T2D). Abnormal extracellular matrix (ECM) remodelling leads to the release of ECM protein fragments into circulation, reflecting these complications. Endotrophin, a pro-fibrotic and -inflammatory hormone, released during collagen type 6 formation, has been linked to adverse outcomes in T2D, but not previously in a long-term perspective. Aim: To assess the 12-year prognostic value of circulating endotrophin levels, measured by PRO-C6, to predict the risk of major adverse cardiovascular events (MACE) in a large cohort of individuals with T2D. Methods: Endotrophin levels were measured with the NordicPRO-C6™ ELISA in 909 serum samples from the Thousand&2 study, which was initiated in 2011 and examined individuals with T2D, with and without known CVD. Clinical data were collected at baseline. Follow-up was 100% complete and performed on the 1 st of May 2024 with the registration of data on MACE from the Danish national registers. The primary outcome was MACE, defined as incident events of hospital admission for ischemic heart disease, heart failure, stroke, or all-cause mortality. PRO-C6 was split into tertiles and examined for survival probability by Kaplan-Meier analysis. Univariate Cox proportional hazard regression analysis was conducted to examine the association between PRO-C6 and the risk of MACE. A multivariable Cox model was additionally conducted, adjusted for age at baseline, sex, systolic blood pressure, duration of diabetes, HbA1c, estimated glomerular filtration rate, use of statins, albuminuria status, and current or prior smoking. Results: The baseline mean (±SD) age of the cohort was 64 (±10) years, 66% were males, mean (±SD) PRO-C6 was 11.9 (±7.01) ng/ml, the median follow-up time was 10.6 years, and number of MACE recorded was 472. The risk of experiencing MACE was significantly higher in the third tertile compared to the first and second tertile (Log-Rank p < 0.001). In the univariate Cox model, the estimated hazard ratio (HR), corresponding to a 2-fold increase of PRO-C6, was HR [95% Confidence Interval(CI)] = 2.1 [1.8-2.4], P <0.001. In the fully adjusted Cox model, PRO-C6 remained significantly associated with the risk of MACE (HR [95% CI] = 1.5 [1.2-1.8], P <0.001). Conclusion: Elevated circulating endotrophin is associated with MACE in T2D, independent of common risk factors.

Suppression of CDK1/Drp1-Mediated Mitochondrial Fission Attenuates Dexamethasone-Induced Extracellular Matrix Deposition in the Trabecular Meshwork.

Aims: Deposition of extracellular matrix (ECM) in the trabecular meshwork (TM), as induced by dexamethasone (Dex), is believed to play an important role in the onset of glucocorticoid-induced glaucoma (GIG). Abnormal ECM deposition is a consequence of mitochondrial dysfunction. We aimed to clarify how mitochondrial dysfunction leads to ECM deposition within the TM and to support the development of novel therapeutic strategies. Results: In primary human TM cells (pHTMCs) and a Dex acetate-induced murine model of GIG, glucocorticoid administration stimulated both mitochondrial fission and ECM deposition. Excessive mitochondrial fission leads to dysfunction and the overexpression of ECM proteins in pHTMCs. Notably, when pHTMCs were treated with the dynamin-related protein 1 (Drp1) inhibitor Mdivi-1 or with Drp1 siRNA, we observed a marked reduction in Dex-induced mitochondrial damage and ECM proteins in vitro. Furthermore, in C57BL/6J mice, treatment with Mdivi-1 mitigated mitochondrial damage and blocked ECM deposition within the TM. We then used Ro3306 to inhibit the cyclin-dependent kinase (CDK)1-mediated phosphorylation of Drp1 at Ser 616, which restored mitochondrial function and diminished Dex-induced ECM protein expression in pHTMCs. Innovation: This study illuminates the pathogenic mechanism linking mitochondrial dysfunction to ECM deposition in GIG. Our innovative approach revealed that Dex stimulates mitochondrial fission via CDK1-mediated p-Drp1s616 overexpression, which drives ECM accumulation. It offered a novel therapeutic strategy for reducing ECM protein expression by inhibiting excessive mitochondrial fission and restoring mitochondrial function. Conclusion: By targeting the CDK1/Drp1-driven mitochondrial fission process, we can counteract Dex-induced ECM deposition in the TM both invivo and in vitro.

Trabecular Meshwork Abnormalities in a Model of Congenital Glaucoma Due to LTBP2 Mutation.

To characterize early trabecular meshwork (TM) morphologic abnormalities in a feline model of human primary congenital glaucoma (PCG) caused by mutation in LTBP2. Eyes from 41 cats, including 19 normal and 22 homozygous for LTBP2 mutation, across various postnatal stages (birth, 2 weeks, 5 weeks, and 12 weeks) were paraformaldehyde fixed, anterior segments dissected, post-fixed in glutaraldehyde, osmicated, and processed and sectioned for transmission electron microscopy. Cell morphology, nuclear shape, and intertrabecular space (ITS) were quantitatively assessed, and the structure of the fibrillar extracellular matrix in the TM was systematically evaluated. The earliest differences in TM morphology between PCG and normal cats were identified at 2 weeks postnatally. Elastic fibers in the TM were discontinuous and disorganized (P = 0.0122), and by 5 weeks of age PCG cats presented significantly less ITS (P = 0.0076) and morphologically rounder TM cells than normal cats (P = 0.0293). By 12 weeks of age, the ITS was further collapsed (P < 0.0001), and the TM cells were morphologically elongated and attenuated in PCG compared to controls (P = 0.0028). In this feline model of PCG due to LTBP2 mutation, development of ultrastructural TM extracellular matrix abnormalities are first observed by 2 weeks and cellular abnormalities by 5 weeks of age. By 12 weeks of age, when intraocular pressure becomes significantly elevated, the TM morphologic abnormalities are already well established. These findings suggest that the postnatal period between 0 and 5 weeks of age is critical for TM and PCG development and progression in cats.

Macrophage erythropoietin signaling promotes macrophage-myofibroblast transformation and fibroblast-myofibroblast differentiation

While myofibroblasts are the key cause of abnormal extracellular matrix accumulation, the origin of which has not yet been fully elucidated. Recently, it has been found that macrophage-myofibroblast transformation (MMT) defined by the expression of both macrophage markers (F4/80 or CD68) and myofibroblast markers (α-SMA) is one of its important sources. In the process of MMT, it is unclear whether epor is involved. In this study, when BMDM was induced by tgf-β1, the number of F4/80+α-SMA+ cells increased, the cells polarized toward M2, and the expression of tgf-β1 increased. After the activation of epor, the number of F4/80 +α-SMA + cells and the polarization level of M2 were further increased. At the same time, we found that the conditioned medium from MMT cells could induce the activation of 3T3 cells with increased the expression of α-SMA and col-1. In contrast, the number of F4/80+α-SMA + cells, the polarization of M2, and the expression of Tgf-β1 decreased after epor was inhibited by siRNA. Our results demonstrate that the activation of epor in BMDMs could promote the transformation of macrophage-myofibroblast induced by TGF-β1.

Astragaloside IV alleviates skin fibrosis by modulating fibroblast phenotype in keloids.

Keloids are fibroproliferative diseases featuring abnormal fibroblast proliferation and extracellular matrix (ECM) deposition. Current therapeutic methods for keloids are unsatisfactory, and the recurrence rates of keloids are high. Astragaloside IV (AS-IV) is a key active component of Astragalus membranaceus Bunge, and has been reported to exert potent anti-fibrotic effects. Accordingly, our research aimed to explore whether AS-IV suppresses fibroblast dysfunction and skin fibrosis during the development of keloids. Human keloid-derived fibroblasts (KFs) were stimulated by TGF-β1 to evaluate the influence of AS-IV on abnormal proliferation, migration, and accumulation of ECM in vitro. A bleomycin (BLM)-induced skin fibrosis model was established to assess the influence of AS-IV on ECM deposition and skin fibrosis in vivo. TGF-β1 stimulation enhanced the proliferation, migration, and accumulation of ECM in KFs, which were abolished by AS-IV treatment. The in vivo assay revealed that AS-IV administration restrained ECM accumulation and skin fibrosis in mouse models. AS-IV plays an anti-fibrotic role in keloids by suppressing fibroblast dysfunction and reducing ECM deposition.

Inflammation proteomic profiling of psychosis in young adults: Findings from the ALSPAC birth cohort

Psychotic disorder is associated with altered levels of various inflammatory markers in blood, but existing studies have typically focused on a few selected biomarkers, have not examined specific symptom domains notably negative symptoms, and are based on individuals with established/chronic illness. Based on data from young people aged 24 years from the Avon Longitudinal Study of Parents and Children (ALSPAC), a UK birth cohort, we have examined the associations of 67 plasma immune/inflammatory proteins assayed using the Olink Target 96 Inflammation panel with psychotic disorder, positive (any psychotic experiences and definite psychotic experiences) and negative symptoms, using linear models with empirical Bayes estimation. The analyses included between 2317 and 2854 individuals. After adjustment for age, sex, body mass index and smoking and correction for multiple testing, positive symptoms and psychotic disorder were consistently associated with upregulation of CDCP1 and IL-6, and psychotic disorder was additionally associated with upregulation of MMP-10. Negative symptoms were associated with upregulation of CDCP1 and TRAIL. CDCP1 and MMP-10 are novel markers of psychosis identified in this study, and are involved in immune regulation, immune cell activation/migration, blood-brain barrier disruption, and extracellular matrix abnormalities. Our findings highlight psychosis symptom domains have overlapping and distinct immune associations, and support a role of inflammation and immune dysfunction in the pathogenesis of psychosis.

Identification of a new human senescent skin cell marker ribonucleoside-diphosphate reductase subunit M2 B.

In skin aging, it has been hypothesized that aging fibroblasts accumulate within the epidermal basal layer, dermis, and subcutaneous fat, causing abnormal tissue remodeling and extracellular matrix dysfunction, thereby inducing an aging-related secretory phenotype (SASP). A new treatment for skin aging involves the specific elimination of senescent skin cells, especially fibroblasts within the dermis and keratinocytes in the basal layer. This requires the identification of specific protein markers of senescent cells, such as ribonucleoside-diphosphate reductase subunit M2 B (RRM2B), which is upregulated in various malignancies in response to DNA stress damage. However, the behavior and role of RRM2B in skin aging remain unclear. Therefore, we examined whether RRM2B functions as a senescence marker using a human dermal fibroblast model of aging. In a model of cellular senescence induced by replicative aging and exposure to ionizing radiation or UVB, RRM2B was upregulated at the gene and protein levels. This was correlated with decreased uptake of the senescence-associated β-galactosidase activity and proliferation marker bromodeoxyuridine. RRM2B upregulation was concurrent with the increased expression of SASP factor genes. Furthermore, using fluorescence flow cytometry, RRM2B-positive cells were recovered more frequently in the aging cell population. In aging human skin, RRM2B was also found to be more abundant in the dermis and epidermal basal layer than other proteins. Therefore, RRM2B may serve as a clinical marker to identify senescent skin cells.

Microvascular and cellular dysfunctions in Alzheimer’s disease: an integrative analysis perspective

Alzheimer’s disease (AD) is the most common cause of dementia, characterized by memory loss, cognitive decline, personality changes, and various neurological symptoms. The role of blood–brain barrier (BBB) injury, extracellular matrix (ECM) abnormalities, and oligodendrocytes (ODCs) dysfunction in AD has gained increasing attention, yet the detailed pathogenesis remains elusive. This study integrates single-cell sequencing of AD patients’ cerebrovascular system with a genome-wide association analysis. It aims to elucidate the associations and potential mechanisms behind pericytes injury, ECM disorder, and ODCs dysfunction in AD pathogenesis. Finally, we identified that abnormalities in the pericyte PI3K–AKT–FOXO signaling pathway may be involved in the pathogenic process of AD. This comprehensive approach sheds new light on the complex etiology of AD and opens avenues for advanced research into its pathogenesis and therapeutic strategies.

Research Progress on Extracellular Matrix Involved in the Development of Preeclampsia.

Preeclampsia (PE) is a serious pregnancy complication, and its primary clinical manifestations are gestational hypertension and proteinuria. Trophoblasts are responsible for the basic functions of the placenta during placental development; recent studies have revealed that placental "shallow implantation" caused by the decreased invasiveness of placental trophoblasts plays a crucial role in PE pathogenesis. The interaction between the cells and the extracellular matrix (ECM) plays a crucial role in trophoblast proliferation, differentiation, and invasion. Abnormal ECM function can result in insufficient migration and invasion of placental trophoblasts, thus participating in PE. This article summarizes the recent studies on the involvement of ECM components, including small leucine-rich proteoglycans, syndecans, glypicans, laminins, fibronectin, collagen, and hyaluronic acid, in the development of PE. ECM plays various roles in PE development, most notably by controlling the activities of trophoblasts. The ECM is structurally stable and can serve as a biological diagnostic marker and therapeutic target for PE.

Role of SAA1 in endometrial extracellular matrix remodeling in polycystic ovary syndrome: implication for pregnancy loss.

Abnormal endometrial extracellular matrix (ECM) remodeling compromises endometrial receptivity and diminishes the probability of a successful live birth. Serum amyloid A1 (SAA1), a modulator of inflammation, is elevated in the circulation of polycystic ovary syndrome (PCOS) patients and involved in ECM remodeling during tissue repair. However, the specific role of SAA1 in endometrial ECM remodeling and subsequent risk of pregnancy loss in PCOS patients remains unclear. To examine the role and underlying mechanism of SAA1 in ECM remodeling in the endometrium of PCOS patients. Serum samples from PCOS and control patients were utilized to investigate the relationship between the abundance of SAA1 and pregnancy loss. Human endometrial tissues and primary human endometrial stromal cells were used to examine the role and underlying mechanism of SAA1 in ECM remodeling. Serum SAA1 concentration was elevated and could serve as an independent risk of pregnancy loss in PCOS patients. Increased SAA1 abundance was also observed in endometrium obtained from these patients. Further mechanistic studies showed that SAA1 stimulated collagen I chains synthesis (COL1A1 and COL1A2) in endometrial stromal cells, suggesting excessive SAA1 may contribute to endometrial ECM remodeling, resulting in a non-supportive environment for ongoing pregnancy. This effect was abolished by either a toll-like receptors 2/4 antagonist or a nuclear factor κB inhibitor. The locally elevated levels of SAA1 in endometrium contribute to ECM over-deposition by inducing collagen I synthesis in PCOS patients, which may hamper embryo implantation and increase the risk of pregnancy loss. These observations highlight the crucial role of heightened SAA1 in orchestrating endometrial dysfunction and shed light on potential therapeutic avenues for improving reproductive outcomes in PCOS patients.

The Role of Long Noncoding RNAs in Vascular Smooth Muscle Cell Phenotype and the Pathogenesis of Cardiovascular and Cerebrovascular Aneurysms.

Aneurysms are localized dilations of blood vessels, which can expand to 50% of the original diameter. They are more common in cardiovascular and cerebrovascular vessels. Rupture is one of the most dangerous complications. The pathophysiology of aneurysms is complex and diverse, often associated with progressive vessel wall dysfunction resulting from vascular smooth muscle cell death and abnormal extracellular matrix synthesis and degradation. Multiple studies have shown that long noncoding RNAs (lncRNAs) play a significant role in the progression of cardiovascular and cerebrovascular diseases. Therefore, it is necessary to find and summarize them. LncRNAs control gene expression and disease progression by regulating target mRNA or miRNA and are biomarkers for the diagnosis and prognosis of aneurysmal cardiovascular and cerebrovascular diseases. This review explores the role, mechanism, and clinical value of lncRNAs in aneurysms, providing new insights for a deeper understanding of the pathogenesis of cardiovascular and cerebrovascular aneurysms.

Identification of non-coding RNA signatures in idiopathic pulmonary fibrosis.

Idiopathic pulmonary fibrosis (IPF) is a deadly, chronic, progressive, irreversible interstitial lung disease characterized by the formation of scar tissue resulting in permanent lung damage. The average survival time following diagnosis is only 3-5years, with a 5-year survival rate shorter than that of many cancers. Alveolar epithelial cell injury followed by irregular repair is the primary pathological process observed in patients with IPF. An evident characteristic of IPF is the development of fibroblastic foci representing active fibrotic areas. Most of the cells within these foci are believed to be myofibroblasts, which are thought to be the primary source of abnormal extracellular matrix production in IPF. The lung phenotype in IPF is characterized by significantly different processes from healthy lungs, including irregular apoptosis, oxidative stress, and epithelial-mesenchymal transition (EMT) pathways. The exact cause of IPF is not fully understood and remains mysterious. It is not suppressing that non-coding RNAs are involved in the development and progression of IPF. Accordingly, here we aimed to identify non-coding RNA molecules during TGFβ-induced myofibroblast activation. Differential expression and functional enrichment analysis were employed to reveal the impact of non-coding RNAs during TGFβ-associated lung fibrosis. Remarkably, LOC101448202, CZ1P-ASNS, LINC01503, IER3-AS1, MIR503HG, CLMAT3, LINC02593, ACTA2-AS1, LOC102723692, LOC107985728, and LOC105371064 were identified to be differentially altered during TGFβ-stimulated myofibroblast activation. These findings strongly suggest that the mechanism of lung fibrosis is heavily under control of non-coding RNAs, and RNA-based therapies could be a promising approach for future therapeutic interventions to lung fibrosis.

Guttae Morphology After Cultured Corneal Endothelial Cell Transplant in Fuchs Endothelial Corneal Dystrophy

Whether guttae in Fuchs endothelial corneal dystrophy (FECD) can be removed by polishing without Descemet stripping and whether postoperative maintenance of reduced guttae can be achieved through cultured corneal endothelial cell (CEC) transplant therapy are critical issues to be addressed. To investigate the decrease of guttae through polishing degenerated CECs and abnormal extracellular matrix (ECM) without Descemet stripping and to observe the behavior of guttae following cultured CEC transplant. This case series prospective observational study was conducted in a hospital outpatient clinic setting. Between December 2013 and January 2019, 22 eyes with corneal endothelial failure caused by FECD received cultured CEC transplant therapy at Kyoto Prefectural University Hospital. Of these, 15 eyes were consistently monitored at the same central corneal area during the preoperative phase, as well as in the early (within 1 year) and late (after 3 years) postoperative phases. The images from these phases were categorized into 3 groups: typical guttae, atypical guttae, and no guttae. Cultured CEC transplant therapy. Proportion of guttae in the observable area was measured, comparing the early and late postoperative phases for each group. The mean age of the patients at the time of surgery was 69 years (range, 49-79 years). All 15 eyes exhibited the presence of confluent guttae preoperatively (100%). Among these, 3 of 15 eyes belonged to male patients. The early postoperative phase of guttae morphologies was classified into 3 groups: 5 eyes with typical guttae, 7 with atypical guttae, and 3 with no guttae. The decrease in the number of these guttae was achieved by surgical procedures. The median percentage of guttae in the typical guttae, atypical guttae, and no guttae groups was 41.8%, 44.4%, and 16.2%, respectively, in the early phase, and 42.2%, 38.2%, and 18.8%, respectively, in the late phase. The findings demonstrate that in some cases of FECD, guttae can be removed by scraping and polishing abnormal ECM and degenerated CECs, while preserving the Descemet membrane. Furthermore, cultured CEC transplant resulted in no increase in guttae for up to 3 years, providing insights into surgically eliminating guttae.

Protective Effect of Nicotinamide Riboside on Glucocorticoid-Induced Glaucoma: Mitigating Mitochondrial Damage and Extracellular Matrix Deposition.

Glucocorticoid-induced glaucoma (GIG) is a prevalent complication associated with glucocorticoids (GCs), resulting in irreversible blindness. GIG is characterized by the abnormal deposition of extracellular matrix (ECM) in the trabecular meshwork (TM), elevation of intraocular pressure (IOP), and loss of retinal ganglion cells (RGCs). The objective of this study is to investigate the effects of nicotinamide riboside (NR) on TM in GIG. Primary human TM cells (pHTMs) and C57BL/6J mice responsive to GCs were utilized to establish in vitro and in vivo GIG models, respectively. The study assessed the expression of ECM-related proteins in TM and the functions of pHTMs to reflect the effects of NR. Mitochondrial morphology and function were also examined in the GIG cell model. GIG progression was monitored through IOP, RGCs, and mitochondrial morphology. Intracellular nicotinamide adenine dinucleotide (NAD+) levels of pHTMs were enzymatically assayed. NR significantly prevented the expression of ECM-related proteins and alleviated dysfunction in pHTMs after dexamethasone treatment. Importantly, NR protected damaged ATP synthesis, preventing overexpression of mitochondrial reactive oxygen species (ROS), and also protect against decreased mitochondrial membrane potential induced by GCs in vitro. In the GIG mouse model, NR partially prevented the elevation of IOP and the loss of RGCs. Furthermore, NR effectively suppressed the excessive expression of ECM-associated proteins and mitigated mitochondrial damage in vivo. Based on the results, NR effectively enhances intracellular levels of NAD+, thereby mitigating abnormal ECM deposition and TM dysfunction in GIG by attenuating mitochondrial damage induced by GCs. Thus, NR has promising potential as a therapeutic candidate for GIG treatment.

M48 - Chronic Alcohol Self Administration Induces Extracellular Matrix Abnormalities in the Hippocampus of Non-Human Primates

M48 - Chronic Alcohol Self Administration Induces Extracellular Matrix Abnormalities in the Hippocampus of Non-Human Primates

Therapeutic potential of human stem cell-derived extracellular vesicles in idiopathic pulmonary fibrosis

Idiopathic pulmonary fibrosis (IPF) is a lethal and chronic lung disease that occurs due to persistent epithelial cell injury and abnormal extracellular matrix (ECM) deposition. Extracellular vesicles (EVs) have been proposed as a potential therapeutic option of IPF because of their functions, such as anti-inflammation, anti-fibrosis, microenvironment regulation, and tissue repair. In this study, we investigated the therapeutic potential of human adipose-derived mesenchymal stem cell (AD-MSC) EVs in IPF model. AD-MSC EVs were isolated by a multi-filtration system based on the tangential flow filtration (TFF) and characterized using transmission electron microscopy (TEM), dynamic light scattering (DLS), flow cytometry analysis, zeta potential, and small RNA sequencing. In vitro analysis reveals that AD-MSC EVs treatments inhibited migration of pulmonary fibroblasts and myofibroblast differentiation through down regulation of fibrosis-associated TGF-β and WNT signaling. In addition, inhalation treatment of AD-MSC EVs significantly alleviated bleomycin (BLM)-induced pulmonary fibrosis. These results reveal that AD-MSC EVs are highly promising as a treatment option for pulmonary fibrosis.

Unraveling the Cardiac Matrix: From Diabetes to Heart Failure, Exploring Pathways and Potential Medications.

Myocardial infarction (MI) often leads to heart failure (HF) through acute or chronic maladaptive remodeling processes. This establishes coronary artery disease (CAD) and HF as significant contributors to cardiovascular illness and death. Therefore, treatment strategies for patients with CAD primarily focus on preventing MI and lessening the impact of HF after an MI event. Myocardial fibrosis, characterized by abnormal extracellular matrix (ECM) deposition, is central to cardiac remodeling. Understanding these processes is key to identifying new treatment targets. Recent studies highlight SGLT2 inhibitors (SGLT2i) and GLP-1 receptor agonists (GLP1-RAs) as favorable options in managing type 2 diabetes due to their low hypoglycemic risk and cardiovascular benefits. This review explores inflammation's role in cardiac fibrosis and evaluates emerging anti-diabetic medications' effectiveness, such as SGLT2i, GLP1-RAs, and dipeptidyl peptidase-4 inhibitors (DPP4i), in preventing fibrosis in patients with diabetes post-acute MI. Recent studies were analyzed to identify effective medications in reducing fibrosis risk in these patients. By addressing these areas, we can advance our understanding of the potential benefits of anti-diabetic medications in reducing cardiac fibrosis post-MI and improve patient outcomes in individuals with diabetes at risk of HF.

Aging-Associated Metabolite Methylmalonic Acid Increases Susceptibility to Pulmonary Fibrosis

Idiopathic pulmonary fibrosis (IPF) is a progressive interstitial lung disease characterized by pulmonary fibroblast overactivation, resulting in the accumulation of abnormal extracellular matrix and lung parenchymal damage. Although the pathogenesis of IPF remains unclear, aging was proposed as the most prominent nongenetic risk factor. Propionate metabolism undergoes reprogramming in the aging population, leading to the accumulation of the by-product methylmalonic acid (MMA). This study aimed to explore alterations in propionate metabolism in IPF and the impact of the by-product MMA on pulmonary fibrosis. It revealed alterations in the expression of enzymes involved in propionate metabolism within IPF lung tissues, characterized by an increase in propionyl-CoA carboxylase and methylmalonyl-CoA epimerase expression, and a decrease in methylmalonyl-CoA mutase expression. Knockdown of methylmalonyl-CoA mutase, the key enzyme in propionate metabolism, induced a profibrotic phenotype and activated co-cultured fibroblasts in A549 cells. MMA exacerbated bleomycin-induced mouse lung fibrosis and induced a profibrotic phenotype in both epithelial cells and fibroblasts through activation of the canonical transforming growth factor-β/Smad pathway. Overall, these findings unveil an alteration of propionate metabolism in IPF, leading to MMA accumulation, thus exacerbating lung fibrosis through promoting profibrotic phenotypic transitions via the canonical transforming growth factor-β/Smad signaling pathway.

An Ultrasound‐Responsive and In Situ Gelling Hydrogel Nanocomposite for Boosting Anti PD‐L1 Immunotherapy via Remodeling Aberrant ECM of Post‐Surgical Residual Cancer

AbstractTumor recurrence and metastasis following surgery remain formidable challenges. Although that is a crucial factor in determining efficacy of postoperative immune treatment, the impact of surgery on tumor microenvironment (TME) is still understudied and the specific treatment options for residual cancer are unsatisfactory. Here, it is verified that abnormal extracellular matrix (ECM) of postsurgical residual cancer results in deteriorative hypoxia, immunosuppression, and hypo‐perfusion, which further promotes invasion and may hinder efficacy of immune checkpoint blockades (ICB). To adaptively potentiate ICB therapy in this context, an ultrasound‐responsive, visualized, and in situ gelling hydrogel nanocomposite (TPP ALG) is prepared through combining phase change nanoparticles and alginate solution for normalizing ECM with controllable delivery of tranilast. After injection and gelling with ions in situ, TPP ALG enables ultrasound visualized and responsive local delivery and long‐term retention, capable of normalizing ECM, improving hypoxia, remodeling immunosuppressive microenvironment, and enhancing ICB permeation for boosting immunotherapy. Ultimately, this TPP ALG and ICB synergistic treatment approach effectively inhibit local recurrence and lung metastasis post operation, thereby delaying survival. Therefore, based on clinical drug and biocompatible materials, the simple‐synthesized hydrogel nanocomposite holds great application prospects for boosting ICB and inhibiting postsurgical cancer recurrence and metastasis.