Targeting of αv integrin identifies a core molecular pathway that regulates fibrosis in several organs

Histone lactylation-augmented IRF4 is implicated in arsenite-induced liver fibrosis via modulating Th17 cell differentiation

Arsenic, a ubiquitous environmental toxicant, has been implicated in causing liver fibrosis through chronic exposure. Histone lactylation is involved in various inflammatory diseases, among which liver fibrosis is included, and is also closely related to the regulation of immune cells. This work focuses on the mechanisms of histone lactylation and Th17 cell differentiation in arsenite-induced liver fibrosis through animal and cellular experiments. Chronic arsenite exposure of mice led to liver fibrosis, elevated glycolysis in liver, and increased lactate levels in both serum and liver, which promoted Th17 cell differentiation of CD4+ T cells and increased IL-17A secretion. Treatment with oxamate, a lactate dehydrogenase inhibitor, suppressed Th17 cell differentiation and alleviated fibrosis in the liver. For HepG2 cells, arsenite exposure enhanced glycolysis and lactate levels, leading to increased global lactylation (Kla), H3K18la, interferon-regulatory factor 4 (IRF4), retinoic acid receptor-related orphan receptor gamma t (RORγt), and IL-17A expression and secretion in co-cultured Jurkat cells. Furthermore, in Jurkat cells, reducing lactate production and transport decreased these protein levels, suppressed Th17 cell differentiation, decreased IL-17A secretion, and ultimately inhibited the activation of hepatic stellate cells (HSCs). These results indicate that lactate derived from hepatocytes promotes Th17 cell differentiation by upregulating IRF4 through H3K18la, thereby enhancing IL-17A secretion and the activation of HSCs, contributing to arsenite-induced liver fibrosis. Our work reveals a new mechanism of histone lactylation in arsenite-induced liver fibrosis and offers a fresh perspective for the development of strategies for prevention and treatment of this condition.

An antisense oligonucleotide targeting the heat-shock protein HSPB5 as an innovative therapeutic approach in pulmonary fibrosis

BACKGROUND AND PURPOSE

Idiopathic pulmonary fibrosis (IPF) is a fatal disease characterized by fibroblast activation and abnormal accumulation of extracellular matrix in the lungs. We previously demonstrated the importance of the heat shock protein αB-crystallin (HSPB5) in TGF-β1 profibrotic signalling, which suggests that HSPB5 could be a new therapeutic target for the treatment of IPF. The purpose of this study was thus to develop antisense oligonucleotides targeting HSPB5 and to study their effects on the development of experimental pulmonary fibrosis.

EXPERIMENTAL APPROACH

Specific antisense oligonucleotides (ASO) were designed and screened in vitro, based on their ability to inhibit human and murine HSPB5 expression. The selected ASO22 was characterized in vitro in human fibroblast CCD-19Lu cells and A549 epithelial pulmonary cells, as well as in vivo using a mouse model of bleomycin-induced pulmonary fibrosis.

KEY RESULTS

ASO22 was selected for its capacity to inhibit TGF-β1-induced expression of HSPB5 and additional key markers of fibrosis such as plasminogen activator inhibitor-1, collagen, fibronectin and α-smooth muscle actin in fibroblastic human CCD-19Lu cells as well as plasminogen activator inhibitor-1 and α-smooth muscle actin in pulmonary epithelial A549 cells. Intra-tracheal or intravenous administration of ASO22 in bleomycin-induced pulmonary fibrotic mice decreased HSPB5 expression and reduced fibrosis, as demonstrated by decreased pulmonary remodelling, collagen accumulation and Acta2 and Col1a1 expression.

CONCLUSION AND IMPLICATIONS

Our results suggest that an antisense oligonucleotide strategy targeting HSPB5 could be of interest for the treatment of IPF.

Crosstalk between Hepatic Stellate Cells and Hepatic Macrophages in Metabolic Dysfunction-Associated Steatohepatitis

Metabolic dysfunction-associated steatotic liver disease is the most prevalent liver condition worldwide. Its more severe manifestation, metabolic dysfunction-associated steatohepatitis (MASH), is accompanied by distinctive hepatocellular injury and inflammation with fibrosis. The involvement of chronic inflammation and accompanying immune cell activation in the maturation phases of MASH progression, mediated through hepatic stellate cells (HSCs), plays a central role. This review highlights the detailed molecular and cellular mechanisms of MASH, with special attention to the dynamic dialogue between HSCs and hepatic macrophages. This review will help narrow the existing gaps, with a summary of key roles HSCs and hepatic macrophages play within liver immunity to inflammation, discussing critical intercellular communication pathways as well as proposing new venues for research toward a better understanding of MASH pathobiology, which could pave ways toward breakthroughs in the clinical condition.

Precision nanomedicine for pneumonocyte-targeting: Emerging strategies and clinical prospects in refractory pulmonary disease therapy

Refractory pulmonary diseases, including chronic obstructive pulmonary disease (COPD) and tuberculosis (TB), pose a critical global health challenge due to the limitations of conventional therapies in advanced stages, such as poor drug penetration, systemic side effects, and inability to eradicate pathogens in protected microenvironments. While the lung's complex structure is essential for respiratory function, it also facilitates persistent damage from environmental and infectious agents. Nanomedicine provides a transformative approach by utilizing customizable carriers (e.g., ligand-gated targeting, stimuli-responsive payload release) to bypass physiological barriers through both passive mechanisms such as enhanced vascular permeability and active-targeting. Such platforms achieve hierarchical drug deposition-from organ-level accumulation to pneumonocyte-targeting-thereby addressing the spatial heterogeneity of therapy-resistant lesions. Besides, A unique advantage of nanomedicine lies in its intrinsic interactions with lung immune cells (e.g., macrophages), allowing dual-functional systems that not only deliver therapeutics to disease sites but also modulate local immune responses-such as reducing inflammation in COPD or enhancing bacterial clearance in TB. This targeted approach improves treatment efficacy while minimizing systemic toxicity. Furthermore, nanomedicine ensures the stability of encapsulated drugs, particularly nucleic acid therapeutics (siRNA, mRNA), which are crucial for treating genetic defect-related pulmonary diseases. Building on the relationship between malignant pulmonary conditions and lung cells, this review summarizes nanoplatform-based strategies for precise targeting and examines ongoing clinical trials. By bridging the gap between preclinical research and clinical application, this review aims to guide the development of novel therapeutic approaches and accelerate the clinical translation of nanomedicines for refractory pulmonary diseases.

Hepatic stellate cell-derived Delta-like 1 is dispensable for injury-induced liver fibrosis

Chronic liver injury results in fibrosis and ultimately progresses to cirrhosis. Delta-like 1 (DLK1) has been implicated in the activation of myofibroblasts derived from hepatic stellate cells (HSCs) in the context of liver injury; however, the specific cellular origins of DLK1 remain a subject of debate. In this study, we demonstrate that DLK1 originating from HSCs is not essential for liver fibrosis resulting from chemical injury. The Dlk1 gene was expressed at comparable levels in primary hepatocytes and HSCs isolated from normal adult mice. Following liver injury induced by carbon tetrachloride (CCl4) intoxication, Dlk1 expression was markedly upregulated alongside the myofibroblast marker Pdgfrβ, α-SMA, and collagen genes in the liver. Conditional deletion of the Dlk1 gene in HSCs via Pdgfrb-Cre-mediated recombination did not significantly alter Dlk1 expression levels in either normal or injured whole liver. Importantly, the absence of Dlk1 in HSCs did not affect the elevation of plasma transaminases, hepatocyte proliferation, or Pdgfrβ activation during CCl4-induced acute liver injury. Moreover, during chronic liver injury and fibrosis, the loss of Dlk1 in HSCs did not influence HSCs activation, collagen deposition, or the expression of collagen genes (Col1a, Col3a). Collectively, our findings suggest that HSC-derived DLK1 is not critical for the activation of myofibroblasts and liver fibrosis.

Multimodal Imaging Demonstrates Antifibrotic Effects of Targeting αvβ6/αvβ1 Integrins in Biliary Fibrosis

OBJECTIVES

Development of molecular therapies for liver fibrosis is slowed by a lack of noninvasive methods addressing questions of target expression, target engagement, and treatment response. Integrin αvβ6 is a biomarker of liver fibrosis that is upregulated in livers of patients with primary sclerosing cholangitis. It activates latent TGF-β and plays a critical role in regulating extracellular matrix expression, especially collagen. In this study, our aim was to use combined αvβ6 integrin-targeted positron emission tomography (PET) and collagen-specific magnetic resonance imaging (MRI) to measure target expression/engagement and liver fibrosis reduction with a αvβ6 integrin inhibitor.

MATERIALS AND METHODS

We conducted a treatment study in bile duct-ligated (BDL) rats using a small molecule inhibitor to αvβ6/αvβ1. 68Ga-DOTA-R01-MG, an αvβ6-specific PET probe, was used to noninvasively measure αvβ6 expression and target engagement in the liver. CM-101, a type I collagen MRI probe, was used to quantify fibrosis.

RESULTS

68Ga-DOTA-R01-MG PET showed 3-fold higher liver uptake in BDL rats compared with sham rats at 17 days after surgery. Pretreatment with high dose αvβ6/αvβ1 inhibitor 1 hour before imaging significantly decreased liver PET uptake in BDL rats (31%, P = 0.012). Two weeks of daily dosing with an αvβ6/αvβ1 inhibitor attenuated αvβ6 expression in BDL rat liver as assessed by αvβ6 PET (0.27 ± 0.07 percent injected dose [%ID]/mL compared with 0.40 ± 0.09 %ID/mL in vehicle-treated group, P = 0.014) and reduced liver fibrosis as assessed by collagen MRI (liver relaxation rate change ΔR1 = 0.14 ± 0.11 vs 0.36 ± 0.06, P = 0.0037). Imaging findings were confirmed by histology (collagen proportionate area 10.7 ± 2.8% vs 22.5 ± 6.1%, P < 0.001).

CONCLUSIONS

A single imaging protocol combining molecular MRI and PET can be used to effectively monitor integrin inhibitor treatment by measuring target expression/engagement and treatment outcomes. Multimodality molecular imaging may be valuable in accelerating drug development in molecular therapies for liver fibrosis.

Collagen V regulates renal function after kidney injury and can be pharmacologically targeted to enhance kidney repair in mice

Kidney fibrosis determines clinical outcomes in individuals with chronic kidney disease (CKD). The stoichiometric ratio of collagens in renal scar differs from that of healthy kidney extracellular matrix (ECM), but the functional importance of altered collagen types in injured kidneys remains unclear. Using human population studies, we show that circulating protein and renal mRNA amounts of collagen V A1 (COL5A1) exhibited associations with kidney disease and incident CKD risk. We show that Col5a1 regulates the degree of postinjury fibrosis and renal function. Mice with conditionally knocked out Col5a1 (Col5a1 CKO) exhibited decreased renal function and greater renal fibrosis after dietary adenine- or ureteric obstruction-mediated kidney injury. Renal fibroblasts in Col5a1 CKO animals up-regulated the profibrotic αvβ3 integrin. Inhibition of αvβ3 signaling with a small molecule, cilengitide, rescued postinjury renal function in Col5a1 CKO animals. Using the hybrid mouse diversity panel that comprises 100 diverse inbred strains of mice, we observed that gene expression of Col5a1 after injury exhibited genetic variation across 100 strains. Strains with low Col5a1 expression after injury exhibited worse renal function compared with animals that had higher degrees of expression. We next measured Col5a1 expression in peripheral blood mononuclear cells in mice to identify nonresponder strains that did not have increased Col5a1 expression after kidney injury. We observed that administration of cilengitide in nonresponder strains significantly rescued postinjury renal fibrosis and function. These studies point to the feasibility of precision medicine approaches to target Col5a1 for enhancing renal repair.

Antifibrotic therapeutic strategies in systemic sclerosis: Critical role of the Wnt/β-catenin and TGF-β signal transduction pathways as potential targets

Systemic sclerosis (SSc) is a prototypic fibrosing disorder characterized by widespread fibrosis and immune dysregulation. Current evidence highlights the intricate cross-talk between the canonical Wnt/β-catenin signaling pathway and transforming growth factor-beta (TGF-β) signaling, both of which play fundamental roles in the pathogenesis of fibrosis. This review aims to elucidate the central role of the Wnt/β-catenin-TGF-β pathway and TGF-β signal transduction pathway in fibrotic diseases, focusing on SSc. We summarized evidence from cellular biology studies, animal model investigations and clinical observations to provide a comprehensive view of the mechanisms causing pathological fibrosis. In addition, we explore the possibilities of antifibrotic therapeutic strategies against Wnt/β-catenin-TGF-β signaling to counteract fibrosis, delineating approaches for treatment of SSc patients by targeting these interconnected signaling pathways.

Periductal fibroblasts participate in liver homeostasis, fibrosis, and tumorigenesis

Hepatic fibroblasts comprise groups of stromal cells in the liver that are phenotypically distinct from hepatic stellate cells. However, their physiology is poorly understood. By single-cell RNA sequencing, we identified Cd34 and Dpt as hepatic fibroblast-specific genes. Cd34-CreER labeled periportal-venous and periductal fibroblasts, but few pericentral-venous fibroblasts. Cd34+ fibroblasts generated ∼25% of myofibroblasts in periportal fibrosis and ∼40% of cancer-associated fibroblasts (CAFs) in intrahepatic cholangiocarcinoma (ICC). Myofibroblast formation by Cd34+ fibroblasts required Tgfbr2. Depletion of Cd34+ fibroblasts increased the frequency of the ductal epithelial cells under homeostasis and accelerated the progression of ICC. Dpt-CreER labeled periportal- and pericentral-venous fibroblasts, but much less periductal fibroblasts. Dpt+ cells generated ∼15% of myofibroblasts in periportal fibrosis, but few myofibroblasts in pericentral fibrosis or CAFs in ICC. Thus, an orthogonal combination of Cd34-CreER and Dpt-CreER dissected the fates of periductal, periportal-venous, and pericentral-venous fibroblasts. Both periductal and periportal-venous fibroblasts contribute to liver fibrosis. Periductal fibroblasts also contribute to ductal homeostasis and ICC progression.

Dual-Integrin-Targeted Supramolecular Peptide Nanoarchitectonics for Enhanced Hepatic Delivery and Antifibrotic Therapy

The integration of integrin-binding peptides within self-assembling building blocks is crucial for the development of targeted nanoarchitectonics. However, such constructs typically incorporate only a single integrin-binding peptide, limiting their multifunctionality. Herein, a rationally designed self-assembling peptide with dual integrin-binding motifs for α5β1 and αvβ3 is presented. This peptide forms highly ordered nanofibers or nanoparticles (VH-NPs) with tailored secondary structures. In vitro and in vivo studies demonstrate that VH-NPs target activated hepatic stellate cells via dual-integrin interactions, enabling selective targeting to fibrotic livers and suppressing α5β1 and αvβ3. Notably, VH-NPs can encapsulate rhein through noncovalent interactions, resulting in peptide-rhein nanoarchitectonics that display augmented antifibrotic effects. These findings highlight the potential of self-assembling peptides that leverage multiple targets and therapeutic modules as a promising strategy for constructing multifunctional nanoarchitectonics.

Targeting cardiac fibrosis with Chimeric Antigen Receptor-Engineered Cells

Cardiac fibrosis poses a significant challenge in cardiovascular diseases due to its intricate pathogenesis, and there is currently no standardized and effective treatment approach. The fibrotic process entails the involvement of various cell types and molecular mechanisms, such as fibroblast activation and proliferation, increased collagen synthesis, and extracellular matrix rearrangement. Traditional therapies often fall short in efficacy or carry substantial side effects. However, recent studies have shown that Chimeric Antigen Receptor T (CAR-T) cells can selectively target and eliminate activated cardiac fibroblasts (CFs) in mice, leading to reduced cardiac fibrosis and improved myocardial tissue compliance. This breakthrough presents a new and promising avenue for treating cardiac fibrosis. Currently, CAR-T cell-based therapy for cardiac fibrosis is undergoing animal experimentation, indicating ample scope for enhancement. Future investigations could explore the application of CAR cell therapy in cardiac fibrosis treatment, including the potential of CAR-natural killer (CAR-NK) cells and CAR macrophages (CAR-M), offering novel insights and strategies for combating cardiac fibrosis.

Large-scale proteomic analyses of incident Parkinson's disease reveal new pathophysiological insights and potential biomarkers

The early pathophysiology of Parkinson's disease (PD) is poorly understood. We analyzed 2,920 Olink-measured plasma proteins in 51,804 UK Biobank participants, identifying 859 incident PD cases after 14.45 years. We found 38 PD-related proteins, with six of the top ten validated in the Parkinson's Progression Markers Initiative (PPMI) cohort. ITGAV, HNMT and ITGAM showed consistent significant association (hazard ratio: 0.11-0.57, P = 6.90 × 10-24 to 2.10 × 10-11). Lipid metabolism dysfunction was evident 15 years before PD onset, and levels of BAG3, HPGDS, ITGAV and PEPD continuously decreased before diagnosis. These proteins were linked to prodromal symptoms and brain measures. Mendelian randomization suggested ITGAM and EGFR as potential causes of PD. A predictive model using machine learning combined the top 16 proteins and demographics, achieving high accuracy for 5-year (area under the curve (AUC) = 0.887) and over-5-year PD prediction (AUC = 0.816), outperforming demographic-only models. It was externally validated in PPMI (AUC = 0.802). Our findings reveal early peripheral pathophysiological changes in PD crucial for developing early biomarkers and precision therapies.

Immunotherapeutic targeting of aging-associated isoDGR motif in chronic lung inflammation

Accumulation of damaged biomolecules in body tissues is the primary cause of aging and age-related chronic diseases. Since this damage often occurs spontaneously, it has traditionally been regarded as untreatable, with typical therapeutic strategies targeting genes or enzymes being ineffective in this domain. In this report, we demonstrate that an antibody targeting the isoDGR damage motif in lung tissue can guide immune clearance of harmful damaged proteins in vivo, effectively reducing age-linked lung inflammation. We observed age-dependent accumulation of the isoDGR motif in human lung tissues, as well as an 8-fold increase in isoDGR-damaged proteins in lung fibrotic tissues compared with healthy tissue. This increase was accompanied by marked infiltration of CD68+/CD11b + macrophages, consistent with a role for isoDGR in promoting chronic inflammation. We therefore assessed isoDGR function in mice that were either naturally aged or lacked the isoDGR repair enzyme. IsoDGR-protein accumulation in mouse lung tissue was strongly correlated with chronic inflammation, pulmonary edema, and hypoxemia. This accumulation also induced mitochondrial and ribosomal dysfunction, in addition to features of cellular senescence, thereby contributing to progressive lung damage over time. Importantly, treatment with anti-isoDGR antibody was able to reduce these molecular features of disease and significantly reduced lung pathology in vivo.

Fibrosis: cross-organ biology and pathways to development of innovative drugs

Fibrosis is a pathophysiological mechanism involved in chronic and progressive diseases that results in excessive tissue scarring. Diseases associated with fibrosis include metabolic dysfunction-associated steatohepatitis (MASH), inflammatory bowel diseases (IBDs), chronic kidney disease (CKD), idiopathic pulmonary fibrosis (IPF) and systemic sclerosis (SSc), which are collectively responsible for substantial morbidity and mortality. Although a few drugs with direct antifibrotic activity are approved for pulmonary fibrosis and considerable progress has been made in the understanding of mechanisms of fibrosis, translation of this knowledge into effective therapies continues to be limited and challenging. With the aim of assisting developers of novel antifibrotic drugs, this Review integrates viewpoints of biologists and physician-scientists on core pathways involved in fibrosis across organs, as well as on specific characteristics and approaches to assess therapeutic interventions for fibrotic diseases of the lung, gut, kidney, skin and liver. This discussion is used as a basis to propose strategies to improve the translation of potential antifibrotic therapies.

Advances in idiopathic pulmonary fibrosis diagnosis and treatment

Significant advances have been made in diagnosing and treating idiopathic pulmonary fibrosis (IPF) in the last decade. The incidence and prevalence of IPF are increasing, and morbidity and mortality remain high despite the two Food and Drug Administration (FDA)-approved medications, pirfenidone and nintedanib. Hence, there is an urgent need to develop new diagnostic tools and effective therapeutics to improve early, accurate diagnosis of IPF and halt or reverse the progression of fibrosis with a better safety profile. New diagnostic tools such as transbronchial cryobiopsy and genomic classifier require less tissue and generally have good safety profiles, and they have been increasingly utilized in clinical practice. Advances in artificial intelligence-aided diagnostic software are promising, but challenges remain. Both pirfenidone and nintedanib focus on growth factor-activated pathways to inhibit fibroblast activation. Novel therapies targeting different pathways and cell types (immune and epithelial cells) are being investigated. Biomarker-based personalized medicine approaches are also in clinical trials. This review aims to summarize recent diagnostic and therapeutic development in IPF.

Targeting skeletal interoception: a novel mechanistic insight into intervertebral disc degeneration and pain management

Despite being a leading cause of chronic pain and disability, the underlying mechanisms of intervertebral disc (IVD) degeneration (IVDD) remain unclear. Emerging evidence suggests that mechanosensation (the ability of the skeletal system to perceive mechanical and biochemical signals) mediated by abnormal mechanical loading plays a critical role in the regulation of IVD health. This review examines the complex interactions amongIVDs, intraosseous sensory mechanisms, and the central nervous system (CNS), with a particular focus on the roles of pathways such as PGE2/EP4, Wnt/β-catenin, and NF-κB. This review elucidates the manner in which mechanical stress and aberrant signaling disrupt the homeostasis of the nucleus pulposus (NP), cartilaginous endplate (CEP) and annulus fibrosus (AF), thereby driving degeneration and exacerbating pain. Furthermore, targeted therapeutic strategies, including the modulation of skeletal interoception and dynamic mechanical loading, present novel avenues for reversing IVDD progression. By integrating skeletal biology with spinal pathology, this work offers a novel perspective on the pathogenesis of IVDD and identifies promising strategies for clinical intervention. These findings highlight the potential of targeting skeletal interoception to mitigate IVDD and associated pain, paving the way for innovative, mechanism-driven therapies.

Mechanosignaling via Integrins: Pivotal Players in Liver Fibrosis Progression and Therapy

Liver fibrosis, a consequence of chronic liver injury, represents a major global health burden and is the leading cause of liver failure, morbidity, and mortality. The pathological hallmark of this condition is excessive extracellular matrix deposition, driven primarily by integrin-mediated mechanotransduction. Integrins, transmembrane heterodimeric proteins that serve as primary ECM receptors, orchestrate complex mechanosignaling networks that regulate the activation, differentiation, and proliferation of hepatic stellate cells and other ECM-secreting myofibroblasts. These mechanical signals create self-reinforcing feedback loops that perpetuate the fibrotic response. Recent advances have provided insight into the roles of specific integrin subtypes in liver fibrosis and revealed their regulation of key downstream effectors-including transforming growth factor beta, focal adhesion kinase, RhoA/Rho-associated, coiled-coil containing protein kinase, and the mechanosensitive Hippo pathway. Understanding these mechanotransduction networks has opened new therapeutic possibilities through pharmacological manipulation of integrin-dependent signaling.

Liver diseases: epidemiology, causes, trends and predictions

As a highly complex organ with digestive, endocrine, and immune-regulatory functions, the liver is pivotal in maintaining physiological homeostasis through its roles in metabolism, detoxification, and immune response. Various factors including viruses, alcohol, metabolites, toxins, and other pathogenic agents can compromise liver function, leading to acute or chronic injury that may progress to end-stage liver diseases. While sharing common features, liver diseases exhibit distinct pathophysiological, clinical, and therapeutic profiles. Currently, liver diseases contribute to approximately 2 million deaths globally each year, imposing significant economic and social burdens worldwide. However, there is no cure for many kinds of liver diseases, partly due to a lack of thorough understanding of the development of these liver diseases. Therefore, this review provides a comprehensive examination of the epidemiology and characteristics of liver diseases, covering a spectrum from acute and chronic conditions to end-stage manifestations. We also highlight the multifaceted mechanisms underlying the initiation and progression of liver diseases, spanning molecular and cellular levels to organ networks. Additionally, this review offers updates on innovative diagnostic techniques, current treatments, and potential therapeutic targets presently under clinical evaluation. Recent advances in understanding the pathogenesis of liver diseases hold critical implications and translational value for the development of novel therapeutic strategies.

Update of Aging Hallmarks in Idiopathic Pulmonary Fibrosis

Idiopathic Pulmonary Fibrosis (IPF) is an epithelial-driven interstitial lung disease of unknown etiology characterized by the excessive proliferation of fibroblast populations that synthesize large amounts of extracellular matrix. In this devastating disorder, all aging hallmarks appear prematurely or are altered. This review highlights key findings about IPF characteristics recently recognized as hallmarks of aging, including mechanical alterations, inflammaging, dysbiosis, alternative splicing, and disabled macroautophagy. It also revisits the classic hallmarks of aging, which encompass stem cell exhaustion, cellular senescence, and altered intercellular communication. Enhancing our understanding of the fundamental processes that underlie the altered hallmarks of aging in IPF may facilitate the development of innovative experimental strategies to improve therapeutic outcomes.

Cross-Talk Between Tumor Cells and Stellate Cells Promotes Oncolytic VSV Activity in Intrahepatic Cholangiocarcinoma

As the mechanisms underlying tumorigenesis become better understood, the dynamic roles of cellular components of the tumor microenvironment, and their cross-talk with tumor cells, have come to light as key drivers of disease progression and have emerged as important targets of new cancer therapies. In the field of oncolytic virus (OV) therapy, stromal cells have been considered as potential barriers to viral spread, thus limiting virus replication and therapeutic outcome. However, new evidence indicates that intratumoral fibroblasts could support virus replication. We have demonstrated in a rat model of stromal-rich intrahepatic cholangiocarcinoma (CCA) that vesicular stomatitis virus (VSV) can be localized within intratumoral hepatic stellate cells (HSCs), in addition to tumor cells, when the virus was applied via hepatic arterial infusion. Furthermore, VSV was shown to efficiently kill CCA cells and activated HSCs, and co-culture of CCA and HSCs increased viral titers. Interestingly, this effect is also observed when each cell type is cultured alone in a conditioned medium of the other cell type, indicating that secreted cell factors are at least partially responsible for this phenomenon. Partial reduction in sensitivity to type I interferons was observed in co-culture systems, providing a possible mechanism for the increased viral titers. Together, the results indicate that targeting activated HSCs with VSV could provide an additional mechanism of OV therapy, which, until now has not been considered. Furthermore, these findings suggest that VSV is a potentially powerful therapeutic agent for stromal-rich tumors, such as CCA and pancreatic cancer, both of which are very difficult to treat with conventional therapy and have a very poor prognosis.

Modulation of TGF-β signaling new approaches toward kidney disease and fibrosis therapy

The prevalence of chronic kidney disease (CKD) is increasing worldwide, posing a significant healthcare challenge. Despite the immense burden of CKD, optimal therapies remain limited in impact. Kidney fibrosis is a common mediator of all CKD progression, characterized by excessive extracellular matrix deposition and scarring of kidney parenchyma. Transforming growth factor-β (TGF-β) is a potent pro-fibrotic cytokine that signals through canonical and non-canonical pathways to promote kidney cell damage and fibrosis progression, thus garnering much interest as an optimal therapeutic target for CKD. However, the clinical translation of TGF-β inhibition in CKD and other disease settings has faced substantial challenges, particularly due to the highly pleiotropic effects of TGF-β in organ homeostasis and disease. Here, we review the kidney cell-specific biological effects of TGF-β signaling, discuss the current challenges in therapeutic targeting TGF-β in CKD, and provide the rationale for alternative targeting strategies of TGF-β signaling as potential approaches in CKD therapy. Selective inhibition of TGF-β signaling modulators to fine-tune TGF-β inhibition without a broad blockade may lead to new and safer treatments for CKD.

Using Integrin αvβ6-Targeted Positron Emission Tomography Imaging to Longitudinally Monitor Radiation-Induced Pulmonary Fibrosis In Vivo

PURPOSE

Radiation-induced pulmonary fibrosis (RIPF) is a potentially serious and disabling late complication of radiation therapy. Monitoring RIPF progression is challenging due to the absence of early detection tools and the difficulty in distinguishing RIPF from other lung diseases using standard imaging methods. In the lungs, integrin αvβ6 is crucial in the development of RIPF, acting as a significant activator of transforming growth factor β after radiation injury. This study aimed to investigate integrin αvβ6-targeted positron emission tomography (PET) imaging ([64Cu]Cu-αvβ6-BP) to study RIPF development in vivo.

METHODS AND MATERIALS

We used a focal RIPF model (70 Gy delivered focally to a 3 mm spot in the lung) and a whole lung RIPF model (14 Gy delivered to the whole lung) in adult C57BL/6J mice. Small animal PET/computed tomography images were acquired 1 hour postinjection of 11.1 MBq of [64Cu]Cu-αvβ6-BP. Animals were imaged for 8 weeks in the focal RIPF model and 6 months in the whole lung RIPF model. Immunohistochemistry for integrin αvβ6 and trichrome staining were performed.

RESULTS

In the focal RIPF model, there was focal uptake of [64Cu]Cu-αvβ6-BP in the irradiated region at week 4 that progressively increased at weeks 6 and 8. In the whole lung RIPF model, minimal uptake of the probe was observed at 4 months post-radiation therapy, which significantly increased at months 5 and 6. Expression of integrin αvβ6 was validated histologically by immunohistochemistry in both models.

CONCLUSIONS

Integrin αvβ6-targeted PET imaging using [64Cu]Cu-αvβ6-BP can serve as a useful tool to identify RIPF in vivo.

Metabolism of hepatic stellate cells in chronic liver diseases: emerging molecular and therapeutic interventions

Chronic liver diseases, primarily metabolic dysfunction-associated steatotic liver disease (MASLD), metabolic and metabolic dysfunction-associated alcoholic liver disease (MetALD), and viral hepatitis, can lead to liver fibrosis, cirrhosis, and cancer. Hepatic stellate cell (HSC) activation plays a central role in the development of myofibroblasts and fibrogenesis in chronic liver diseases. However, HSC activation is influenced by the complex microenvironments within the liver, which are largely shaped by the interactions between HSCs and various other cell types. Changes in HSC phenotypes and metabolic mechanisms involve glucose, lipid, and cholesterol metabolism, oxidative stress, activation of the unfolded protein response (UPR), autophagy, ferroptosis, senescence, and nuclear receptors. Clinical interventions targeting these pathways have shown promising results in addressing liver inflammation and fibrosis, as well as in modulating glucose and lipid metabolism and metabolic stress responses. Therefore, a comprehensive understanding of HSC phenotypes and metabolic mechanisms presents opportunities for novel therapeutic approaches aimed at halting or even reversing chronic liver diseases.

Progressive lung fibrosis: reprogramming a genetically vulnerable bronchoalveolar epithelium

Idiopathic pulmonary fibrosis (IPF) is etiologically complex, with well-documented genetic and nongenetic origins. In this Review, we speculate that the development of IPF requires two hits: the first establishes a vulnerable bronchoalveolar epithelium, and the second triggers mechanisms that reprogram distal epithelia to initiate and perpetuate a profibrotic phenotype. While vulnerability of the bronchoalveolar epithelia is most often driven by common or rare genetic variants, subsequent injury of the bronchoalveolar epithelia results in persistent changes in cell biology that disrupt tissue homeostasis and activate fibroblasts. The dynamic biology of IPF can best be contextualized etiologically and temporally, including stages of vulnerability, early disease, and persistent and progressive lung fibrosis. These dimensions of IPF highlight critical mechanisms that adversely disrupt epithelial function, activate fibroblasts, and lead to lung remodeling. Together with better recognition of early disease, this conceptual approach should lead to the development of novel therapeutics directed at the etiologic and temporal drivers of lung fibrosis that will ultimately transform the care of patients with IPF from palliative to curative.

Targeting Fibrosis: From Molecular Mechanisms to Advanced Therapies

As the final stage of disease-related tissue injury and repair, fibrosis is characterized by excessive accumulation of the extracellular matrix. Unrestricted accumulation of stromal cells and matrix during fibrosis impairs the structure and function of organs, ultimately leading to organ failure. The major etiology of fibrosis is an injury caused by genetic heterogeneity, trauma, virus infection, alcohol, mechanical stimuli, and drug. Persistent abnormal activation of "quiescent" fibroblasts that interact with or do not interact with the immune system via complicated signaling cascades, in which parenchymal cells are also triggered, is identified as the main mechanism involved in the initiation and progression of fibrosis. Although the mechanisms of fibrosis are still largely unknown, multiple therapeutic strategies targeting identified molecular mechanisms have greatly attenuated fibrotic lesions in clinical trials. In this review, the organ-specific molecular mechanisms of fibrosis is systematically summarized, including cardiac fibrosis, hepatic fibrosis, renal fibrosis, and pulmonary fibrosis. Some important signaling pathways associated with fibrosis are also introduced. Finally, the current antifibrotic strategies based on therapeutic targets and clinical trials are discussed. A comprehensive interpretation of the current mechanisms and therapeutic strategies targeting fibrosis will provide the fundamental theoretical basis not only for fibrosis but also for the development of antifibrotic therapies.

The integrin adhesome and control of anti-tumour immunity

It is widely regarded that the anti-tumour immune response drives clearance of tumours and leads to prolonged survival in patients. However, tumours are adept at reprogramming the surrounding microenvironment to an immunosuppressive milieu to prevent successful immune directed killing. Adhesion of cells to the extracellular matrix is essential for regulating cellular processes such as survival, proliferation and migration. This adhesion is largely conducted via integrins and their related intracellular signalling networks. Adhesion proteins such as focal adhesion kinase (FAK) are expressed in both tumour cells and cells of the surrounding microenvironment, and are often dysregulated in cancers. Recent work has demonstrated that adhesion proteins are contributing to regulation of the immunosuppressive microenvironment within tumours, and could provide a new avenue to target in combination with immunotherapies. Here, we provide an overview of the effort being made to elucidate the roles adhesion proteins play in modulating anti-tumour responses within a variety of cancer settings. In particular we focus on the multifaceted role of FAK within the tumour immune microenvironment. Finally, we summarise the data in clinical trials, where targeting FAK is being exploited to prime the tumour microenvironment and create potent responses when combined with immunotherapies.

Impaired myofibroblast proliferation is a central feature of pathologic post-natal alveolar simplification

Premature infants with bronchopulmonary dysplasia (BPD) have impaired alveolar gas exchange due to alveolar simplification and dysmorphic pulmonary vasculature. Advances in clinical care have improved survival for infants with BPD, but the overall incidence of BPD remains unchanged because we lack specific therapies to prevent this disease. Recent work has suggested a role for increased transforming growth factor-beta (TGFβ) signaling and myofibroblast populations in BPD pathogenesis, but the functional significance of each remains unclear. Here, we utilize multiple murine models of alveolar simplification and comparative single-cell RNA sequencing to identify shared mechanisms that could contribute to BPD pathogenesis. Single-cell RNA sequencing reveals a profound loss of myofibroblasts in two models of BPD and identifies gene expression signatures of increased TGFβ signaling, cell cycle arrest, and impaired proliferation in myofibroblasts. Using pharmacologic and genetic approaches, we find no evidence that increased TGFβ signaling in the lung mesenchyme contributes to alveolar simplification. In contrast, this is likely a failed compensatory response, since none of our approaches to inhibit TGFβ signaling protect mice from alveolar simplification due to hyperoxia while several make simplification worse. In contrast, we find that impaired myofibroblast proliferation is a central feature in several murine models of BPD, and we show that inhibiting myofibroblast proliferation is sufficient to cause pathologic alveolar simplification. Our results underscore the importance of impaired myofibroblast proliferation as a central feature of alveolar simplification and suggest that efforts to reverse this process could have therapeutic value in BPD.

miR-3606-3p alleviates skin fibrosis by integratively suppressing the integrin/FAK, p-AKT/p-ERK, and TGF-β signaling cascades

INTRODUCTION

Fibroblast abnormalities are crucial causes of skin fibrosis, including systemic sclerosis (SSc) and keloids. However, their mechanisms, including underlying microRNA regulatory mechanisms, remain elusive.

OBJECTIVES

This study aimed to evaluate the roles, mechanisms, and therapeutic potential of miR-3606-3p in regulating multiple fibroblast abnormalities.

METHODS

The miR-3606-3p levels were evaluated in skin tissues and primary fibroblasts. RNA-seq and luciferase assays were employed to identify miR-3606-3p targets. Collagen contraction, western blotting, in vivo imaging, and real-time cellular analysis were used to assess fibroblast abnormalities. The therapeutic potential of miR-3606-3p was evaluated in mice.

RESULTS

MiR-3606-3p decreased in skin tissues (SSc: Fold Change (FC) =  - 2.95, P = 0.0101; keloid: FC =  - 3.42, P < 0.0001) and primary fibroblasts (SSc: FC =  - 12.74, P = 0.0278; keloid: FC =  - 2.08, P = 0.0021) from skin fibrosis patients, and negatively correlated with disease severity. Mechanistically, miR-3606-3p targeted the 3'-untranslated regions (3'-UTRs) of Integrin αV (ITGAV), GRB2-associated binding protein 1 (GAB1), and transforming growth factor beta receptor 2 (TGFBR2), all of these three targets increased in skin fibrosis. Simultaneously, miR-3606-3p inhibited fibroblast's fibrogenesis, migration, inflammation, and proliferation by inhibiting ITGAV/integrin/FAK, GAB1/p-AKT/p-ERK, and TGFBR2/p-SMAD2/3 signaling. ITGAV-mediated integrin/FAK signaling unidirectionally activated the p-AKT/p-ERK and p-SMAD2/3 pathways. Knockdown of GAB1 and TGFRB2 reduced ITGAV-induced p-AKT/p-ERK and p-SMAD2/3 activities. MiR-3606-3p, si-ITGAV, si-GAB1, and si-TGFBR2 exhibited significant inhibition of fibrogenesis and migration. Inflammation was primarily inhibited by si-ITGAV and si-GAB1, while proliferation was primarily inhibited by si-TGFBR2. Moreover, miR-3606-3p significantly attenuates skin fibrosis in keloid-bearing mice.

CONCLUSIONS

MiR-3606-3p is downregulated in skin fibrosis. Moreover, it negatively correlates with disease severity. Functionally, miR-3606-3p inhibits fibrogenesis, migration, inflammation, and proliferation of fibroblasts. Mechanistically, miR-3606-3p inhibits ITGAV, GAB1, and TGFBR2 by targeting their 3'-UTRs. ITGAV-, GAB1-, and TGFBR2-activated integrin/AKT/ERK/SMAD2/3 signaling induced fibroblast abnormalities. In vivo, miR-3606-3p inhibits skin fibrosis in mice. Therefore, the multi-targeting, multi-phenotypic regulatory properties of miR-3606-3p suggest its potential utility in clinical treatment.

A dual αvβ1/αvβ6 integrin inhibitor Bexotegrast (PLN-74809) ameliorates organ injury and fibrogenesis in fibrotic kidney disease

Chronic kidney disease (CKD) is a global public health problem, involving about 10% of the global population. Unfortunately, there are currently no effective drugs. Kidney fibrosis is the main pathology of CKD, where integrins play crucial roles in renal fibrogenesis. Recently, Bexotegrast (PLN-74809) as a dual integrin αvβ1/αvβ6 inhibitor could reduce the degree of lung fibrosis in patients with idiopathic pulmonary fibrosis. However, the role of PLN-74809 remains unclear in fibrotic kidney disease. Here, we have revealed that PLN-74809 administration dose-dependently delayed the progression of renal fibrosis in both adenine diet- and unilateral ureteral obstruction (UUO)-induced mice. Mechanistically, PLN-74809 targeted integrin αvβ1/αvβ6 to inhibit FAK/Src/Akt/β-catenin cascade in fibrotic kidneys. In summary, our results for the first time highlighted the αvβ1/αvβ6 inhibitor PLN-74809 exerted potential therapeutic against kidney fibrosis.

Mechanical network motifs as targets for mechanomedicine

The identification and analysis of network motifs has been widely used in the functional analysis of signaling components, disease discovery and other fields. The positive feedback loop (PFL) is a simple but important network motif. The formation of a PFL is regulated by mechanical cues such as substrate stiffness, fiber stretching and cell compression in the cell microenvironment. Here, we propose a new term, 'mechanical PFL', and analyze the mechanisms of mechanical PFLs at molecular, subcellular and cellular scales. More and more therapies are being targeted against mechanosignaling pathways at the experimental and preclinical stages, and exploring mechanical PFLs as potential mechanomedicine targets could be a new direction for disease treatment.

CX3C chemokine: Hallmarks of fibrosis and ageing

Fibrosis refers to the progressive tissue lesion process characterized by excessive secretion and deposition of extracellular matrix (ECM). Abnormal fibrous tissue deposition distorts tissue architecture and leads to the progressive loss of organ function. Notably, fibrosis is one of the primary pathological appearances of many end stage illnesses, and is considered as a lethal threat to human health, especially in the elderly with ageing-related diseases. CX3C ligand 1 (CX3CL1) is the only member of chemokine CX3C and binds specifically to CX3C receptor 1 (CX3CR1). Different from other chemokines, CX3CL1 possesses both chemotactic and adhesive activity. CX3CL1/CX3CR1 axis involves in various physiological and pathological processes, and exerts a critical role in cells from the immune system, vascular system, and nervous system etc. Notably, increasing evidence has demonstrated that CX3CL1/CX3CR1 signaling pathway is closely related to the pathological process of fibrosis in multiple tissue and organs. We reviewed the crucial role of CX3CL1/CX3CR1 axis in fibrosis and ageing and systematically summarized the underlying mechanism, which offers prospective strategies of targeting CX3C for the therapy of fibrosis and ageing-related diseases.

Potential therapeutic strategies for MASH: from preclinical to clinical development

Current treatment paradigms for metabolic dysfunction-associated steatohepatitis (MASH) are based primarily on dietary restrictions and the use of existing drugs, including anti-diabetic and anti-obesity medications. Given the limited number of approved drugs specifically for MASH, recent efforts have focused on promising strategies that specifically target hepatic lipid metabolism, inflammation, fibrosis, or a combination of these processes. In this review, we examined the pathophysiology underlying the development of MASH in relation to recent advances in effective MASH therapy. Particularly, we analyzed the effects of lipogenesis inhibitors, nuclear receptor agonists, glucagon-like peptide-1 (GLP-1) receptor (GLP-1R) agonists, fibroblast growth factor mimetics, and combinatorial therapeutic approaches. We summarize these targets along with their preclinical and clinical candidates with the ultimate goal of optimizing the therapeutic prospects for MASH.

Inhibition of integrin binding to ligand arg-gly-asp motif induces AKT-mediated cellular senescence in hepatic stellate cells

BACKGROUND & AIMS

Hepatic stellate cells (HSCs) play an essential role in liver fibrogenesis. The induction of cellular senescence has been reported to inhibit HSC activation. Previously, we demonstrated that CWHM12, a small molecule arginine-glycine-aspartic acid (RGD) peptidomimetic compound, inhibits HSC activation. This study investigated whether the inhibitory effects of CWHM12 on HSCs affected cellular senescence.

METHODS

The immortalized human HSC lines, LX-2 and TWNT-1, were used to evaluate the effects of CWHM12 on cellular senescence via the disruption of RGD-mediated binding to integrins.

RESULTS

CWHM12 induces cell cycle arrest, senescence-associated beta-galactosidase activity, acquisition of senescence-associated secretory phenotype (SASP), and expression of senescence-associated proteins in HSCs. Further experiments revealed that the phosphorylation of AKT and murine double minute 2 (MDM2) was involved in the effects of CWHM12, and the inhibition of AKT phosphorylation reversed these effects of CWHM12 on HSCs.

CONCLUSIONS

Pharmacological inhibition of RGD-mediated integrin binding induces senescence in activated HSCs.

Emerging Trends in Gastrointestinal Cancer Targeted Therapies: Harnessing Tumor Microenvironment, Immune Factors, and Metabolomics Insights

Gastrointestinal (GI) cancers are the leading cause of new cancer cases and cancer-related deaths worldwide. The treatment strategies for patients with GI tumors have focused on oncogenic molecular profiles associated with tumor cells. Recent evidence has demonstrated that the tumor cell functions are modulated by its microenvironment, compromising fibroblasts, extracellular matrices, microbiome, immune cells, and the enteric nervous system. Along with the tumor microenvironment components, alterations in key metabolic pathways have emerged as a hallmark of tumor cells. From these perspectives, this review will highlight the functions of different cellular components of the GI tumor microenvironment and their implications for treatment. Furthermore, we discuss the major metabolic reprogramming in GI tumor cells and how understanding metabolic rewiring could lead to new therapeutic strategies. Finally, we briefly summarize the targeted agents currently being studied in GI cancers. Understanding the complex interplay between tumor cell-intrinsic and -extrinsic factors during tumor progression is critical for developing new therapeutic strategies.

Impaired Myofibroblast Proliferation is a Central Feature of Pathologic Post-Natal Alveolar Simplification

Premature infants with bronchopulmonary dysplasia (BPD) have impaired alveolar gas exchange due to alveolar simplification and dysmorphic pulmonary vasculature. Advances in clinical care have improved survival for infants with BPD, but the overall incidence of BPD remains unchanged because we lack specific therapies to prevent this disease. Recent work has suggested a role for increased transforming growth factor-beta (TGFβ) signaling and myofibroblast populations in BPD pathogenesis, but the functional significance of each remains unclear. Here, we utilize multiple murine models of alveolar simplification and comparative single-cell RNA sequencing to identify shared mechanisms that could contribute to BPD pathogenesis. Single-cell RNA sequencing reveals a profound loss of myofibroblasts in two models of BPD and identifies gene expression signatures of increased TGFβ signaling, cell cycle arrest, and impaired proliferation in myofibroblasts. Using pharmacologic and genetic approaches, we find no evidence that increased TGFβ signaling in the lung mesenchyme contributes to alveolar simplification. In contrast, this is likely a failed compensatory response, since none of our approaches to inhibit TGFb signaling protect mice from alveolar simplification due to hyperoxia while several make simplification worse. In contrast, we find that impaired myofibroblast proliferation is a central feature in several murine models of BPD, and we show that inhibiting myofibroblast proliferation is sufficient to cause pathologic alveolar simplification. Our results underscore the importance of impaired myofibroblast proliferation as a central feature of alveolar simplification and suggest that efforts to reverse this process could have therapeutic value in BPD.

Integrins and NAFLD-associated liver diseases: clinical associations, pathophysiological mechanisms and pharmacological implications

Nonalcoholic fatty liver disease (NAFLD) is a leading cause of chronic liver disease and poses a substantial health burden with increasing incidence globally. NAFLD encompasses a spectrum extending from hepatic steatosis to nonalcoholic steatohepatitis (NASH), with the possibility of progressing to cirrhosis or, in severe instances, hepatocellular carcinoma (HCC). NAFLD extends beyond simple metabolic disruption and involves multiple immune cell-mediated inflammatory processes. Integrins are a family of heterodimeric transmembrane cell adhesion receptors that regulate various aspects of NAFLD onset and progression, including hepatocellular steatosis, hepatic stellate cell (HSC) activation and immune cell infiltration. In this review, we comprehensively summarize the involvement of integrins in NAFLD, as well as the downstream signal transduction mediated by these receptors. Furthermore, we present the latest clinical and preclinical findings on drugs that target integrins for steatosis, inflammation, fibrosis and NAFLD-related HCC treatment.

Suppression of OGN in lung myofibroblasts attenuates pulmonary fibrosis by inhibiting integrin αv-mediated TGF-β/Smad pathway activation

BACKGROUND

Idiopathic pulmonary fibrosis (IPF) represents a severe and progressive manifestation of idiopathic interstitial pneumonia marked by an uncertain etiology along with an unfavorable prognosis. Osteoglycin (OGN), belonging to the small leucine-rich proteoglycans family, assumes pivotal functions in both tissue formation and damage response. However, the roles and potential mechanisms of OGN in the context of lung fibrosis remain unexplored.

METHODS

The assessment of OGN expression levels in fibrotic lungs was conducted across various experimental lung fibrosis mouse models. To elucidate the effects of OGN on the differentiation of lung myofibroblasts, both OGN knockdown and OGN overexpression were employed in vitro. The expression of integrin αv, along with its colocalization with lysosomes and latency-associated peptide (LAP), was monitored in OGN-knockdown lung myofibroblasts. Furthermore, the role of OGN in lung fibrosis was investigated through OGN knockdown utilizing adeno-related virus serotype 6 (AAV6)-mediated delivery.

RESULTS

OGN exhibited upregulation in both lungs and myofibroblasts across diverse lung fibrosis mouse models. And laboratory experiments in vitro demonstrated that OGN knockdown inhibited the TGF-β/Smad signaling pathway in lung myofibroblasts. Conversely, OGN overexpression promoted TGF-β/Smad pathway in these cells. Mechanistic insights revealed that OGN knockdown facilitated lysosome-mediated degradation of integrin αv while inhibiting its binding to latency-associated peptide (LAP). Remarkably, AAV6-targeted OGN knockdown ameliorated the extent of lung fibrosis in experimental mouse models.

CONCLUSION

Our results indicate that inhibiting OGN signaling could serve as a promising therapeutic way for lung fibrosis.

Signalling of the neuropeptide calcitonin gene-related peptide (CGRP) through RAMP1 promotes liver fibrosis via TGFβ1/Smad2 and YAP pathways

The liver is innervated by primary sensory nerve fibres releasing the neuropeptide calcitonin gene-related peptide (CGRP). Elevated plasma levels of CGRP have been found in patients with liver fibrosis or cirrhosis. We hypothesised that signalling of CGRP and its receptors might regulate liver fibrosis and propose a novel potential target for the treatment. In this study, hepatic expression of CGRP and its receptor component, the receptor activity-modifying protein 1 (RAMP1), was dramatically increased in diseased livers of patients. In a murine liver fibrosis model, deficiency of RAMP1 resulted in attenuated fibrogenesis characterized by less collagen deposition and decreased activity of hepatic stellate cells (HSC). Mechanistically, activity of the TGFβ1 signalling core component Smad2 was severely impaired in the absence of RAMP1, and Yes-associated protein (YAP) activity was found to be diminished in RAMP1-deficient liver parenchyma. In vitro, stimulation of the HSC line LX-2 cells with CGRP induces TGFβ1 production and downstream signalling as well as HSC activation documented by increased α-SMA expression and collagen synthesis. We further demonstrate in LX-2 cells that CGRP promotes YAP activation and its nuclear translocation subsequent to TGFβ1/Smad2 signals. These data support a promotive effect of CGRP signalling in liver fibrosis via stimulation of TGFβ1/Smad2 and YAP activity.

Altered extracellular matrix-related pathways accelerate the transition from normal to prefibroid myometrium in Black women

BACKGROUND

Black women experience a disproportionate impact of uterine fibroids compared to White women, including earlier diagnosis, higher frequency, and more severe symptoms. The etiology underlying this racial disparity remains elusive.

OBJECTIVE

The aim of this study was to evaluate the molecular differences in normal myometrium (fibroid-free uteri) and at-risk myometrium (fibroid-containing uteri) tissues in Black and White women.

STUDY DESIGN

We conducted whole-genome RNA-seq on normal and at-risk myometrium tissues obtained from both self-identified Black and White women (not Hispanic or Latino) to determine global gene expression profiles and to conduct enriched pathway analyses (n=3 per group). We initially assessed the differences within the same type of tissue (normal or at-risk myometrium) between races. Subsequently, we analyzed the transcriptome of normal myometrium compared to at-risk myometrium in each race and determined the differences between them. We validated our findings through real-time PCR (sample size range=5-12), western blot (sample size range=5-6), and immunohistochemistry techniques (sample size range=9-16).

RESULTS

The transcriptomic analysis revealed distinct profiles between Black and White women in normal and at-risk myometrium tissues. Interestingly, genes and pathways related to extracellular matrix and mechanosensing were more enriched in normal myometrium from Black than White women. Transcription factor enrichment analysis detected greater activity of the serum response transcription factor positional motif in normal myometrium from Black compared to White women. Furthermore, we observed increased expression levels of myocardin-related transcription factor-serum response factor and the serum response factor in the same comparison. In addition, we noted increased expression of both mRNA and protein levels of vinculin, a target gene of the serum response factor, in normal myometrium tissues from Black women as compared to White women. Importantly, the transcriptomic profile of normal to at-risk myometrium conversion differs between Black and White women. Specifically, we observed that extracellular matrix-related pathways are involved in the transition from normal to at-risk myometrium and that these processes are exacerbated in Black women. We found increased levels of Tenascin C, type I collagen alpha 1 chain, fibronectin, and phospho-p38 MAPK (Thr180/Tyr182, active) protein levels in at-risk over normal myometrium tissues from Black women, whereas such differences were not observed in samples from White women.

CONCLUSION

These findings indicate that the racial disparities in uterine fibroids may be attributed to heightened production of extracellular matrix in the myometrium in Black women, even before the tumors appear. Future research is needed to understand early life determinants of the observed racial differences.

Epithelial organoid supports resident memory CD8 T cell differentiation

Resident memory T cells (TRMs) play a vital role in regional immune defense. Although laboratory rodents have been extensively used to study fundamental TRM biology, poor isolation efficiency and low cell survival rates have limited the implementation of TRM-focused high-throughput assays. Here, we engineer a murine vaginal epithelial organoid (VEO)-CD8 T cell co-culture system that supports CD8 TRM differentiation. These in-vitro-generated TRMs are phenotypically and transcriptionally similar to in vivo TRMs. Pharmacological and genetic approaches showed that transforming growth factor β (TGF-β) signaling plays a crucial role in their differentiation. The VEOs in our model are susceptible to viral infections and the CD8 T cells are amenable to genetic manipulation, both of which will allow a detailed interrogation of antiviral CD8 T cell biology. Altogether we have established a robust in vitro TRM differentiation system that is scalable and can be subjected to high-throughput assays that will rapidly add to our understanding of TRMs.

Measuring Integrin Force Loading Rates Using a Two-Step DNA Tension Sensor

Cells apply forces to extracellular matrix (ECM) ligands through transmembrane integrin receptors: an interaction which is intimately involved in cell motility, wound healing, cancer invasion and metastasis. These small (piconewton) integrin-ECM forces have been studied by molecular tension fluorescence microscopy (MTFM), which utilizes a force-induced conformational change of a probe to detect mechanical events. MTFM has revealed the force magnitude for integrin receptors in a variety of cell models including primary cells. However, force dynamics and specifically the force loading rate (LR) have important implications in receptor signaling and adhesion formation and remain poorly characterized. Here, we develop an LR probe composed of an engineered DNA structure that undergoes two mechanical transitions at distinct force thresholds: a low force threshold at 4.7 pN (hairpin unfolding) and a high force threshold at 47 pN (duplex shearing). These transitions yield distinct fluorescence signatures observed through single-molecule fluorescence microscopy in live cells. Automated analysis of tens of thousands of events from eight cells showed that the bond lifetime of integrins that engage their ligands and transmit a force >4.7 pN decays exponentially with a τ of 45.6 s. A subset of these events mature in magnitude to >47 pN with a median loading rate of 1.1 pN s-1 and primarily localize at the periphery of the cell-substrate junction. The LR probe design is modular and can be adapted to measure force ramp rates for a broad range of mechanoreceptors and cell models, thus aiding in the study of molecular mechanotransduction in living systems.

Dopaminylation of endothelial TPI1 suppresses ferroptotic angiocrine signals to promote lung regeneration over fibrosis

Lungs can undergo facultative regeneration, but handicapped regeneration often leads to fibrosis. How microenvironmental cues coordinate lung regeneration via modulating cell death remains unknown. Here, we reveal that the neurotransmitter dopamine modifies the endothelial niche to suppress ferroptosis, promoting lung regeneration over fibrosis. A chemoproteomic approach shows that dopamine blocks ferroptosis in endothelial cells (ECs) via dopaminylating triosephosphate isomerase 1 (TPI1). Suppressing TPI1 dopaminylation in ECs triggers ferroptotic angiocrine signaling to aberrantly activate fibroblasts, leading to a transition from lung regeneration to fibrosis. Mechanistically, dopaminylation of glutamine (Q) 65 residue in TPI1 directionally enhances TPI1's activity to convert dihydroxyacetone phosphate (DHAP) to glyceraldehyde 3-phosphate (GAP), directing ether phospholipid synthesis to glucose metabolism in regenerating lung ECs. This metabolic shift attenuates lipid peroxidation and blocks ferroptosis. Restoring TPI1 Q65 dopaminylation in an injured endothelial niche overturns ferroptosis to normalize pro-regenerative angiocrine function and alleviate lung fibrosis. Overall, dopaminylation of TPI1 balances lipid/glucose metabolism and suppresses pro-fibrotic ferroptosis in regenerating lungs.

Crosstalk in extrahepatic and hepatic system in NAFLD/NASH

Non-alcoholic fatty liver disease (NAFLD) has emerged as the most prevalent chronic liver disease globally. Non-alcoholic steatohepatitis (NASH) represents an extremely progressive form of NAFLD, which, without timely intervention, may progress to cirrhosis or hepatocellular carcinoma. Presently, a definitive comprehension of the pathogenesis of NAFLD/NASH eludes us, and pharmacological interventions targeting NASH specifically remain constrained. The aetiology of NAFLD encompasses a myriad of external factors including environmental influences, dietary habits and gender disparities. More significantly, inter-organ and cellular interactions within the human body play a role in the development or regression of the disease. In this review, we categorize the influences affecting NAFLD both intra- and extrahepatically, elaborating meticulously on the mechanisms governing the onset and progression of NAFLD/NASH. This exploration delves into progress in aetiology and promising therapeutic targets. As a metabolic disorder, the development of NAFLD involves complexities related to nutrient metabolism, liver-gut axis interactions and insulin resistance, among other regulatory functions of extraneous organs. It further encompasses intra-hepatic interactions among hepatic cells, Kupffer cells (KCs) and hepatic stellate cells (HSCs). A comprehensive understanding of the pathogenesis of NAFLD/NASH from a macroscopic standpoint is instrumental in the formulation of future therapies for NASH.

Fibroblast and myofibroblast activation in normal tissue repair and fibrosis

The term 'fibroblast' often serves as a catch-all for a diverse array of mesenchymal cells, including perivascular cells, stromal progenitor cells and bona fide fibroblasts. Although phenotypically similar, these subpopulations are functionally distinct, maintaining tissue integrity and serving as local progenitor reservoirs. In response to tissue injury, these cells undergo a dynamic fibroblast-myofibroblast transition, marked by extracellular matrix secretion and contraction of actomyosin-based stress fibres. Importantly, whereas transient activation into myofibroblasts aids in tissue repair, persistent activation triggers pathological fibrosis. In this Review, we discuss the roles of mechanical cues, such as tissue stiffness and strain, alongside cell signalling pathways and extracellular matrix ligands in modulating myofibroblast activation and survival. We also highlight the role of epigenetic modifications and myofibroblast memory in physiological and pathological processes. Finally, we discuss potential strategies for therapeutically interfering with these factors and the associated signal transduction pathways to improve the outcome of dysregulated healing.

Activation of alveolar epithelial ER stress by β-coronavirus infection disrupts surfactant homeostasis in mice: implications for COVID-19 respiratory failure

COVID-19 syndrome is characterized by acute lung injury, hypoxemic respiratory failure, and high mortality. Alveolar type 2 (AT2) cells are essential for gas exchange, repair, and regeneration of distal lung epithelium. We have shown that the causative agent, severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2), and other members of the β-coronavirus genus induce an endoplasmic reticulum (ER) stress response in vitro; however, the consequences for host AT2 cell function in vivo are less understood. To study this, two murine models of coronavirus infection were used-mouse hepatitis virus-1 (MHV-1) in A/J mice and a mouse-adapted SARS-CoV-2 strain. MHV-1-infected mice exhibited dose-dependent weight loss with histological evidence of distal lung injury accompanied by elevated bronchoalveolar lavage fluid (BALF) cell counts and total protein. AT2 cells showed evidence of both viral infection and increased BIP/GRP78 expression, consistent with activation of the unfolded protein response (UPR). The AT2 UPR included increased inositol-requiring enzyme 1α (IRE1α) signaling and a biphasic response in PKR-like ER kinase (PERK) signaling accompanied by marked reductions in AT2 and BALF surfactant protein (SP-B and SP-C) content, increases in surfactant surface tension, and emergence of a reprogrammed epithelial cell population (Krt8+ and Cldn4+). The loss of a homeostatic AT2 cell state was attenuated by treatment with the IRE1α inhibitor OPK-711. As a proof-of-concept, C57BL6 mice infected with mouse-adapted SARS-CoV-2 demonstrated similar lung injury and evidence of disrupted surfactant homeostasis. We conclude that lung injury from β-coronavirus infection results from an aberrant host response, activating multiple AT2 UPR stress pathways, altering surfactant metabolism/function, and changing AT2 cell state, offering a mechanistic link between SARS-CoV-2 infection, AT2 cell biology, and acute respiratory failure.NEW & NOTEWORTHY COVID-19 syndrome is characterized by hypoxemic respiratory failure and high mortality. In this report, we use two murine models to show that β-coronavirus infection produces acute lung injury, which results from an aberrant host response, activating multiple epithelial endoplasmic reticular stress pathways, disrupting pulmonary surfactant metabolism and function, and forcing emergence of an aberrant epithelial transition state. Our results offer a mechanistic link between SARS-CoV-2 infection, AT2 cell biology, and respiratory failure.

The fate and role of the pericytes in myocardial diseases

The adult mammalian heart contains a large population of pericytes that play important roles in homeostasis and disease. In the normal heart, pericytes regulate microvascular permeability and flow. Myocardial diseases are associated with marked alterations in pericyte phenotype and function. This review manuscript discusses the role of pericytes in cardiac homeostasis and disease. Following myocardial infarction (MI), cardiac pericytes participate in all phases of cardiac repair. During the inflammatory phase, pericytes may secrete cytokines and chemokines and may regulate leukocyte trafficking, through formation of intercellular gaps that serve as exit points for inflammatory cells. Moreover, pericyte contraction induces microvascular constriction, contributing to the pathogenesis of 'no-reflow' in ischemia and reperfusion. During the proliferative phase, pericytes are activated by growth factors, such as transforming growth factor (TGF)-β and contribute to fibrosis, predominantly through secretion of fibrogenic mediators. A fraction of pericytes acquires fibroblast identity but contributes only to a small percentage of infarct fibroblasts and myofibroblasts. As the scar matures, pericytes form a coat around infarct neovessels, promoting stabilization of the vasculature. Pericytes may also be involved in the pathogenesis of chronic heart failure, by regulating inflammation, fibrosis, angiogenesis and myocardial perfusion. Pericytes are also important targets of viral infections (such as SARS-CoV2) and may be implicated in the pathogenesis of cardiac complications of COVID19. Considering their role in myocardial inflammation, fibrosis and angiogenesis, pericytes may be promising therapeutic targets in myocardial disease.

Advances in drug delivery-based therapeutic strategies for renal fibrosis treatment

Renal fibrosis is the result of all chronic kidney diseases and is becoming a major global health hazard. Currently, traditional treatments for renal fibrosis are difficult to meet clinical needs due to shortcomings such as poor efficacy or highly toxic side effects. Therefore, therapeutic strategies that target the kidneys are needed to overcome these shortcomings. Drug delivery can be attained by improving drug stability and addressing controlled release and targeted delivery of drugs in the delivery category. By combining drug delivery technology with nanosystems, controlled drug release and biodistribution can be achieved, enhancing therapeutic efficacy and reducing toxic cross-wise effects. This review discusses nanomaterial drug delivery strategies reported in recent years. Firstly, the present review describes the mechanisms of renal fibrosis and anti-renal fibrosis drug delivery. Secondly, different nanomaterial drug delivery strategies for the treatment of renal injury and fibrosis are highlighted. Finally, the limitations of these strategies are also discussed. Investigating various anti-renal fibrosis drug delivery strategies reveals the characteristics and therapeutic effects of various novel nanosystem-derived drug delivery approaches. This will serve as a reference for future research on drug delivery strategies for renal fibrosis treatment.

Depletion of Activated Hepatic Stellate Cells and Capillarized Liver Sinusoidal Endothelial Cells Using a Rationally Designed Protein for Nonalcoholic Steatohepatitis and Alcoholic Hepatitis Treatment

Nonalcoholic steatohepatitis (NASH) and alcoholic hepatitis (AH) affect a large part of the general population worldwide. Dysregulation of lipid metabolism and alcohol toxicity drive disease progression by the activation of hepatic stellate cells and the capillarization of liver sinusoidal endothelial cells. Collagen deposition, along with sinusoidal remodeling, alters sinusoid structure, resulting in hepatic inflammation, portal hypertension, liver failure, and other complications. Efforts were made to develop treatments for NASH and AH. However, the success of such treatments is limited and unpredictable. We report a strategy for NASH and AH treatment involving the induction of integrin αvβ3-mediated cell apoptosis using a rationally designed protein (ProAgio). Integrin αvβ3 is highly expressed in activated hepatic stellate cells (αHSCs), the angiogenic endothelium, and capillarized liver sinusoidal endothelial cells (caLSECs). ProAgio induces the apoptosis of these disease-driving cells, therefore decreasing collagen fibril, reversing sinusoid remodeling, and reducing immune cell infiltration. The reversal of sinusoid remodeling reduces the expression of leukocyte adhesion molecules on LSECs, thus decreasing leukocyte infiltration/activation in the diseased liver. Our studies present a novel and effective approach for NASH and AH treatment.

Vascular remodelling in cardiovascular diseases: hypertension, oxidation, and inflammation

Optimal vascular structure and function are essential for maintaining the physiological functions of the cardiovascular system. Vascular remodelling involves changes in vessel structure, including its size, shape, cellular and molecular composition. These changes result from multiple risk factors and may be compensatory adaptations to sustain blood vessel function. They occur in diverse cardiovascular pathologies, from hypertension to heart failure and atherosclerosis. Dynamic changes in the endothelium, fibroblasts, smooth muscle cells, pericytes or other vascular wall cells underlie remodelling. In addition, immune cells, including macrophages and lymphocytes, may infiltrate vessels and initiate inflammatory signalling. They contribute to a dynamic interplay between cell proliferation, apoptosis, migration, inflammation, and extracellular matrix reorganisation, all critical mechanisms of vascular remodelling. Molecular pathways underlying these processes include growth factors (e.g., vascular endothelial growth factor and platelet-derived growth factor), inflammatory cytokines (e.g., interleukin-1β and tumour necrosis factor-α), reactive oxygen species, and signalling pathways, such as Rho/ROCK, MAPK, and TGF-β/Smad, related to nitric oxide and superoxide biology. MicroRNAs and long noncoding RNAs are crucial epigenetic regulators of gene expression in vascular remodelling. We evaluate these pathways for potential therapeutic targeting from a clinical translational perspective. In summary, vascular remodelling, a coordinated modification of vascular structure and function, is crucial in cardiovascular disease pathology.