The extracellular matrix: not just pretty fibrils

Tumor organoids in cancer medicine: from model systems to natural compound screening

CONTEXT

The advent of tissue engineering and biomedical techniques has significantly advanced the development of three-dimensional (3D) cell culture systems, particularly tumor organoids. These self-assembled 3D cell clusters closely replicate the histopathological, genetic, and phenotypic characteristics of primary tissues, making them invaluable tools in cancer research and drug screening.

OBJECTIVE

This review addresses the challenges in developing in vitro models that accurately reflect tumor heterogeneity and explores the application of tumor organoids in cancer research, with a specific focus on the screening of natural products for antitumor therapies.

METHODS

This review synthesizes information from major databases, including Chemical Abstracts, Medicinal and Aromatic Plants Abstracts, ScienceDirect, Google Scholar, Scopus, PubMed and Springer Link. Publications were selected without date restrictions, using terms such as 'organoid', 'natural product', 'pharmacological', 'extract', 'nanomaterial' and 'traditional uses'. Articles related to agriculture, ecology, synthetic work or published in languages other than English were excluded.

RESULTS AND CONCLUSIONS

The review identifies key challenges related to the efficiency and variability of organoid generation and discusses ongoing efforts to enhance their predictive capabilities in drug screening and personalized medicine. Recent studies utilizing patient-derived organoid models for natural compound screening are highlighted, demonstrating the potential of these models in developing new classes of anticancer agents. The integration of natural products with patient-derived organoid models presents a promising approach for discovering novel anticancer compounds and elucidating their mechanisms of action.

New insights into therapeutic strategies for targeting hepatic macrophages to alleviate liver fibrosis

Liver fibrosis is a wound-healing response induced by persistent liver damage, resulting from complex multicellular interactions and multifactorial networks. Without intervention, it can progress to cirrhosis and even liver cancer. Current understanding suggests that liver fibrosis is reversible, making it crucial to explore effective therapeutic strategies for its alleviation. Chronic inflammation serves as the primary driver of liver fibrosis, with hepatic macrophages playing a dual role depending on their polarization state. This review summarizes various prevention and therapeutic strategies targeting hepatic macrophages in the context of liver fibrosis. These strategies include inhibition of macrophage recruitment, modulation of macrophage activation and polarization, regulation of macrophage metabolism, and induction of phagocytosis and autophagy in hepatic macrophages. Additionally, we discuss the communication between hepatic macrophages, hepatocytes, and hepatic stellate cells (HSCs), as well as the current clinical application of anti-fibrotic drugs targeting macrophages. The goal is to identify effective therapeutic targets at each stage of macrophage participation in liver fibrosis development, with the aim of using hepatic macrophages as a target for liver fibrosis treatment.

From blockage to biology: Unveiling the role of extracellular matrix dynamics in obstructive colorectal cancer pathogenesis

Colorectal cancer obstruction is a common problem with distinct symptomatic clues on CT/MR images even under incomplete conditions. The choice of management in the emergency setting has a significant effect on the prognosis of obstructive and nonobstructive colorectal cancer patients. Previous studies have demonstrated that obstruction in colorectal cancer is associated with significantly poorer outcomes, alongside distinct alterations in the composition of the extracellular matrix. Based on accumulating evidence, it is hypothesized that ECM remodeling plays a pivotal role in the development of colorectal cancer obstruction. This review explores the pathological features of obstructive colorectal cancer, emphasizing extracellular matrix remodeling as a central process. Key mechanisms include tumor-stromal cell interactions, tumor cell aggregation and migration mediated by the peripheral nervous system, vascular and lymphatic remodeling within the tumor microenvironment, and microbiota-mediated regulation of cancer progression. These findings demonstrate that further remodeling of the extracellular matrix may be a molecular biological feature of obstructive colorectal cancer with poor prognosis.

Comparative transcriptome analysis identified genes involved in ovarian development in Takifugu rubripes

Ovarian development is a complex process involving multiple genes, but the molecular mechanisms underlying this process in Takifugu rubripes remain poorly understood. This study aimed to identify genes associated with ovarian development in T. rubripes and to investigate the regulatory mechanisms of oocyte maturation. Transcriptome data were compared across four different developmental stages (stage II to V) to identify differentially expressed genes (DEGs) and perform GO and KEGG enrichment analysis. The expression patterns of randomly selected genes were then validated by qPCR. The results yielded a total of 1,289,401,820 raw data from all libraries, with 16,929 DEGs identified across all comparison groups. The DEGs were predominantly enriched in ovarian steroidogenesis, estrogen-mediated signaling, and TGF-beta signaling pathways. The qPCR analysis showed that cyp17a1 was identified as being expressed at similar levels in stage II and III. Thereafter, cyp17a1 was observed to undergo a continuous increase in expression from stage III to V. cyp19a1, nanos1, foxl2 and ar were identified as being expressed at similar levels at stage II and III, then increase in expression from stage III to IV and subsequent downregulation from stage IV to V. hsd17b1 was identified as being expressed at similar levels at stage II and IV. This study represents a transcriptomic study of ovarian development in female T. rubripes. Several essential ovarian-related genes and sex-related biological pathways were identified. The results will improve our understanding of the molecular mechanisms underlying ovarian development in this species.

Label-Free Prediction of Fluorescently Labeled Fibrin Networks

While fluorescent labeling has been the standard for visualizing fibers within fibrillar scaffold models of the extracellular matrix (ECM), the use of fluorescent dyes can compromise cell viability and photobleach prematurely. The intricate fibrillar composition of ECM is crucial for its viscoelastic properties, which regulate intracellular signaling and provide structural support for cells. Naturally derived biomaterials such as fibrin and collagen replicate these fibrillar structures, but longitudinal confocal imaging of fibers using fluorescent dyes may impact cell function and photobleach the sample long before termination of the experiment. An alternative technique is reflection confocal microscopy (RCM) that provides high-resolution images of fibers. However, RCM is sensitive to fiber orientation relative to the optical axis, and consequently, many fibers are not detected. We aim to recover these fibers. Here, we propose a deep learning tool for predicting fluorescently labeled optical sections from unlabeled image stacks. Specifically, our model is conditioned to reproduce fluorescent labeling using RCM images at 3 laser wavelengths and a single laser transmission image. The model is implemented using a fully convolutional image-to-image mapping architecture with a hybrid loss function that includes both low-dimensional statistical and high-dimensional structural components. Upon convergence, the proposed method accurately recovers 3-dimensional fibrous architecture without substantial differences in fiber length or fiber count. However, the predicted fibers were slightly wider than original fluorescent labels (0.213 ± 0.009 μm). The model can be implemented on any commercial laser scanning microscope, providing wide use in the study of ECM biology.

Synthetic Reversible Fibrous Network Hydrogels Based on a Double-Helical Polyelectrolyte

The unique mechanical properties of fibrous networks in biological tissues have inspired the development of synthetic fibrous network hydrogels, yet few polymers can reversibly form such structures. Here, we report the first reversible fibrous network hydrogel composed of synthetic polyelectrolytes with extremely rigid conformation (persistence length is ∼1 µm), made up of double-helical poly(2,2'-disulfonyl-4,4'-benzidine terephthalamide) (PBDT) and tetrabutylphosphonium bromide ([P4444]Br). The hydrogel exhibits a unique sol-gel transition, triggered by the hydrophobicity increase of [P4444]Br above lower critical solution temperature (LCST). This drives PBDT aggregation into fibrous bundles through electrostatic interactions. These bundles grow and branch into a continuous network, with the molecular rigidity of PBDT's double-helix conformation being key to gel formation. The hydrogel displays strain-stiffening mechanical responses akin to biological systems and shows a significant hysteresis (21 °C) between heating and cooling cycles. Uniquely, the effects of salts on the transition temperature deviate from the Hofmeister series, highlighting coordination with sulfonate groups as the dominant factor. Leveraging its modulus change during gelation, the hydrogel was successfully applied as a spray coating on superhydrophobic vertical Teflon surfaces. This study broadens the scope of thermoreversible hydrogels introducing gelation mechanisms for rigid polyelectrolytes and demonstrates their potential in advanced coatings.

Proteomic Characterization of Extracellular Vesicles from Human Neural Precursor Cells: A Promising Advanced Therapy for Neurodegenerative Diseases

Background

The therapeutic effect of stem cells is attributed to their direct maturation into somatic cells and their paracrine effects, which influence the extracellular environment. One such component released is extracellular vesicles containing proteins and genetic materials with immunomodulatory functions and facilitating cell-to-cell communication.

Purpose

The study's main objective was to characterize extracellular vesicles (EVs) from Human Neural Precursor Cells (hNPCs).

Methods

Wharton's Jelly mesenchymal stem cells (WJ-MSCs) were isolated by explant technique and characterized by flow cytometry and trilineage differentiation. The hNPCs obtained from neurospheres were produced by seeding WJ-MSCs on a natural functional biopolymer matrix. EVs derived from WJ-MSCs and hNPCs were isolated by precipitation methodology and characterized by flow cytometry, nanoparticle tracking analysis (NTA), scanning electron microscopy (TEM), and proteomic.

Results

hNPCs expressed proteins and genes characteristic of neural precursor cells. The EVs were characterized by flow cytometry and showed varied expression for the markers CD63, CD9, and CD81, indicating different subpopulations based on their origin of formation. NTA and TEM of the EVs exhibited characteristic size, shape, and structural integrity consistent with the criteria established by the International Society for Extracellular Vesicles (ISEV). EV-hNPCs function enrichment analysis of the proteomic results showed that these vesicles presented abundant proteins directly involved in neuronal biological processes such as plasticity, transduction, postsynaptic density, and overall brain development.

Discussion

The results indicate that EVs derived from hNPCs maintain key neural precursor characteristics and exhibit marker variability, suggesting distinct subpopulations. Their structural integrity aligns with ISEV standards, supporting their potential as reliable biological entities. The proteomic analysis highlights their role in neuronal functions, reinforcing their applicability in neurodegenerative research and therapeutic strategies.

Conclusion

The EVs were successfully isolated from hNPCs with abundant proteins involved in neuronal processes, making them attractive for acellular therapies to treat neurodegenerative diseases.

Mapping in situ the assembly and dynamics in aqueous supramolecular polymers

Supramolecular polymers, bonded through directional non-covalent interactions, closely mimic dynamic behaviors of biological nanofibers. However, the complexity of assembly pathways makes it highly challenging to unravel the nature of supramolecular dynamics in aqueous environments. Here we introduce a precise combinatorial titration methodology to probe in situ the assembly of peptide amphiphiles (PAs). This approach reveals a binary assembly mechanism governed by equilibrium between spheroidal micelles and β-sheet polymers. Weakening hydrogen bonding shifts the equilibrium towards micelles and decreases the internal structural order of filamentous polymers, promoting supramolecular dynamics. Extending this methodology to two-component copolymerization systems, we find a surprising tendency to form blocky nanostructures with reduced internal phase separation as the mismatch in peptide sequence decreases. Interestingly, while well-mixed copolymers acquire different dynamics, mismatched ones retain the characteristic supramolecular motion of their homopolymer counterparts. These critical insights into supramolecular dynamics offer strategies to tailor the dynamic functions of supramolecular nanomaterials.

Engineering Supramolecular Hydrogen Bonding Interactions into Dynamic Covalent Polymers To Obtain Double Dynamic Biomaterials

Inspired by dynamic systems in nature, we can introduce dynamics into synthetic biomaterials through dynamic covalent bonds or supramolecular interactions. Combining both types of dynamic interactions may allow for advanced and innovative networks with multiple levels of dynamicity. Here we present two types of solid materials consisting of either dynamic covalent imine bonds or a combination of these dynamic covalent bonds with supramolecular hydrogen bonding ureido-pyrimidinone (UPy) units to obtain double dynamic materials. We showed the facile synthesis and formulation of both materials at room temperature. The thermal and physical properties of each material are highly tunable by altering the ratio and type of cross-linker. Interestingly, we showed that minimal amounts of UPy units result in a drastic increase in material mechanics. Furthermore, we show that both types of materials are suitable as biomaterials through functionalization with cell-adhesive peptides, through either a dynamic covalent imine bond or a supramolecular UPy moiety.

Electrospun polycaprolactone fibers encapsulating omega-3 and montelukast sodium to prevent capsular contracture in breast implant surgery

Capsular contracture (CC) is a common complication associated with breast implant surgery and is characterized by excessive fibrotic tissue formation around the implant. However, there is no established gold-standard treatment to prevent CC. This study aimed to prepare fish oil/montelukast sodium (MTKS)-loaded polycaprolactone (PCL) fibers and evaluate their effectiveness in preventing CC. PCL, a biocompatible and biodegradable material, was used to fabricate electrospun fibers incorporating fish oil, a source of omega-3 (ω3) polyunsaturated fatty acids (EPA and DHA), and MTKS, a leukotriene receptor antagonist. MTKS and ω3 were selected as therapeutic agents for their anti-inflammatory and anti-fibrotic properties. The fibers underwent characterization using FT-IR, HPLC, SEM, water contact angle, XRD, and TGA. These methods confirmed structural integrity, encapsulation and stability of fish oil, and optimal hydrophilic surface properties for reducing bacterial adhesion to implants. In vitro drug release studies demonstrated the controlled and prolonged release profile of ω3 and a faster release pattern with MTKS. In vivo experiments using a rat model with mini-implants coated with the fibers revealed a significant reduction in fibrotic capsule tissue formation and inflammatory responses compared to control groups after 90 days. Histological and gene expression analyses confirmed these findings. Second-harmonic generation imaging demonstrated that ω3 and MTKS facilitated favorable collagen organization, leading to late-stage fibrosis with a thinner, more compliant capsule, and enhanced biocompatibility. Our findings suggest that PCL-ω3-MTKS fibers regulate inflammatory and fibrotic pathways, improve collagen organization, and reduce the risk of CC. Additionally, ω3-MTKS demonstrated synergistic efficacy in impeding fibrosis. This innovative strategy offers a promising therapeutic approach to mitigate CC and improve outcomes in breast implant surgeries.

Combining spatial transcriptomics and ECM imaging in 3D for mapping cellular interactions in the tumor microenvironment

Tumors are complex ecosystems composed of malignant and non-malignant cells embedded in a dynamic extracellular matrix (ECM). In the tumor microenvironment, molecular phenotypes are controlled by cell-cell and ECM interactions in 3D cellular neighborhoods (CNs). While their inhibition can impede tumor progression, routine molecular tumor profiling fails to capture cellular interactions. Single-cell spatial transcriptomics (ST) maps receptor-ligand interactions but usually remains limited to 2D tissue sections and lacks ECM readouts. Here, we integrate 3D ST with ECM imaging in serial sections from one clinical lung carcinoma to systematically quantify molecular states, cell-cell interactions, and ECM remodeling in CN. Our integrative analysis pinpointed known immune escape and tumor invasion mechanisms, revealing several druggable drivers of tumor progression in the patient under study. This proof-of-principle study highlights the potential of in-depth CN profiling in routine clinical samples to inform microenvironment-directed therapies. A record of this paper's transparent peer review process is included in the supplemental information.

Antibody-Recruiting Surfaces Using Adaptive Multicomponent Supramolecular Copolymers

Multicomponent structures that mediate the clustering of antibodies on cancer cell surfaces are an attractive strategy to unleash innate immune killing mechanisms. However, covalent multifunctional scaffolds that combine cell surface anchoring and antibody binding can be challenging to synthesize and lack adaptability. Here, we present a dynamic multicomponent supramolecular system displaying both antibody- and cell surface-binding motifs, without covalent linkage between them. Supramolecular monomers based on benzene-1,3,5-tricarboxamide (BTA-(OH)3) were functionalized with benzoxaborole (Ba) for surface anchoring (BTA-Ba) or dinitrophenyl (DNP) for antibody binding (BTA-DNP1/3). The multicomponent fibers comprising BTA-(OH)3, BTA-Ba, and BTA-DNP1/3 recruited anti-DNP antibodies to sialic acid-functionalized supported lipid bilayers, indicating that both Ba and DNP remained accessible for binding. Dynamic exchange was demonstrated in a cell-mimicking environment, highlighting the adaptivity of these supramolecular polymers. Despite the complexity of a ternary system, the adaptivity of supramolecular polymers gives the individual components the possibility to act in concert, mimicking natural systems.

A 3D Self-Assembly Platform Integrating Decellularized Matrix Recapitulates In Vivo Tumor Phenotypes and Heterogeneity

Three-dimensional (3D) in vitro cell culture models are invaluable tools for investigating the tumor microenvironment. However, analyzing the impact of critical stromal elements, such as extracellular matrix (ECM), remains a challenge. In this study, we developed a hydrogel-free self-assembly platform to establish ECM-rich 3D "MatriSpheres" to deconvolute cancer cell-ECM interactions. Mouse and human colorectal cancer MatriSpheres actively incorporated microgram quantities of decellularized small intestine submucosa ECM, which proteomically mimicked colorectal cancer tumor ECM compared with traditional formulations like Matrigel. Solubilized ECM, at subgelation concentrations, was organized by colorectal cancer cells into intercellular stroma-like regions within 5 days, displaying morphologic similarity to colorectal cancer clinical pathology. MatriSpheres featured ECM-dependent transcriptional and cytokine profiles associated with malignancy, lipid metabolism, and immunoregulation. Model benchmarking with single-cell RNA sequencing demonstrated that MatriSpheres enhanced correlation with in vivo tumor cells over traditional ECM-poor spheroids. This facile approach enables tumor-specific tissue morphogenesis, promoting cell-ECM communication to improve fidelity for disease modeling applications. Significance: MatriSpheres provide a hydrogel-free 3D platform for decoupling the influence of heterogeneous extracellular matrix components on tumor biology and can broadly facilitate high-throughput drug discovery and screening applications. See related commentary by Ernst and De Wever, p. 1568.

Temporal Proteome Profiling of Anterior Cruciate Ligament Tear Remnants: Secretory Proteins in the Acute Phase Potentially Promote Tissue Repair

Previous studies reported that preserving the anterior cruciate ligament (ACL) remnants following ACL rupture during reconstruction surgery could promote graft healing. However, the temporal proteomic expression of ACL remnants remains unclear. Based on previous reports, we have redefined the initial 6 weeks following ACL rupture as the acute phase and the subsequent 6 weeks to 6 months as the subacute phase. High-throughput proteomic sequencing on ACL remnants from the two groups was utilized. Our study unveiled a total of 381 differential expression proteins (DEPs), with 136 upregulated and 245 downregulated proteins in the acute phase. By intersecting these findings with secretory protein databases, we identified 26 upregulated secretory proteins and 19 downregulated in the acute phase. The upregulation of MMP9 and VTN and the downregulation of COL1A1 and POSTN in the acute phase were further confirmed by immunohistochemistry. These findings suggest that the elevated expression of secretory proteins in the acute phase may play crucial roles in promoting cell proliferation, angiogenesis, and tissue repair of the graft. This study not only enhances our understanding of repair mechanisms in ACL remnant preservation but also provides a theoretical foundation for guiding rational clinical surgical timing.

Dermal fibroblast-derived extracellular matrix (ECM) synergizes with keratinocytes in promoting re-epithelization and scarless healing of skin wounds: Towards optimized skin tissue engineering

Skin serves as the first-order protective barrier against the environment and any significant disruptions in skin integrity must be promptly restored. Despite significant advances in therapeutic strategies, effective management of large chronic skin wounds remains a clinical challenge. Dermal fibroblasts are the primary cell type responsible for remodeling the extracellular matrix (ECM) in wound healing. Here, we investigated whether ECM derived from exogenous fibroblasts, in combination with keratinocytes, promoted scarless cutaneous wound healing. To overcome the limited lifespan of primary dermal fibroblasts, we established reversibly immortalized mouse dermal fibroblasts (imDFs), which were non-tumorigenic, expressed dermal fibroblast markers, and were responsive to TGF-β1 stimulation. The decellularized ECM prepared from both imDFs and primary dermal fibroblasts shared similar expression profiles of extracellular matrix proteins and promoted the proliferation of keratinocyte (iKera) cells. The imDFs-derived ECM solicited no local immune response. While the ECM and to a lesser extent imDFs enhanced skin wound healing with excessive fibrosis, a combination of imDFs-derived ECM and iKera cells effectively promoted the re-epithelization and scarless healing of full-thickness skin wounds. These findings strongly suggest that dermal fibroblast-derived ECM, not fibroblasts themselves, may synergize with keratinocytes in regulating scarless healing and re-epithelialization of skin wounds. Given its low immunogenic nature, imDFs-derived ECM should be a valuable resource of skin-specific biomaterial for wound healing and skin tissue engineering.

Circular Adhesion Substrates Inhibiting Cell Polarization and Proliferation via Graded Texture of Geometric Micropatterns

Most melanomas that occur on the skin surface originate from a newly formed nevus and grow outward in a circular pattern and metastasize from the nevus center. Herein, a circular microfabricated substrate is constructed to explore the growth behavior of melanoma cells. Modeling software is used to calculate appropriate parameters, including shape and size, and then the substrates are processed with microfabrication technologies. The results show that the melanoma cells on the circular adhesion substrate are oval and are significant changes in cell spread length, nuclei, area, aspect ratio, Young's modulus, and orientation angles, indicating inhibition of cell polarization. Moreover, three different layers from circular adhesion substrates are selected to construct new substrates, which indicates that the polarization degree of cells is closely related to the number of micropillar arrays on the circular geometric substrate. In addition, flow cytometry demonstrates that the circular substrate reduced the transition from resting/gap 1 phase (G0/G1) to synthesis phase (S phase), thereby decreasing DNA synthesis and proliferation, reminding a potential method for treatment strategy. More importantly, the circular adhesion substrate influences the integrin signaling pathway, which has a potential application and research prospect in the treatment of melanoma.

Circulating collagen type I fragments as specific biomarkers of cardiovascular outcome risk: Where are the opportunities?

Collagen type I (COL1) is the most abundant protein in the human body and is a main component in the extracellular matrix. The COL1 structure vastly influences normal tissue homeostasis, and changes in the matrix drive progression in multiple diseases. Cardiovascular diseases (CVD) are the leading cause of mortality and morbidity in many Western countries; alterations in the extracellular matrix turnover processes, including COL1, are known to influence the pathophysiological processes leading to CVD outcome. Peptides reflecting COL1 formation and degradation have been established and explored for over two decades in CVD. This review aims to combine and assess the evidence for using COL1-derived circulating peptides as biomarkers in CVD. Secondly, the review identifies existing pitfalls, and evaluates future opportunities for improving the technical characteristics and performance of the biomarkers for implementation in the clinical setting.

Sequential Changes in NOX4 Expression, Oxidative Stress Indices, PIIINP, and Liver Histopathology During Hepatocellular Carcinogenesis Induced in Mice

BACKGROUND AND AIM

Hepatocellular carcinoma (HCC) is a chronic disease caused by complex histological and biochemical changes related to oxidative stress leading to fibrosis, cirrhosis, and malignancy. Knowing the sequential changes in different stages of HCC development is essential for understanding the mechanisms of HCC pathogenesis.

METHODS

This study was designed to evaluate alterations in NADPH oxidase 4 (NOX4) expression and oxidative stress during HCC progression in mice, induced with administration of diethylnitrosamine (DEN, 50 mg/kg) and phenobarbitone (PB, 500 mg/L via drinking water). The correlation of N-terminal propeptide type III collagen (PIIINP) as a serum indicator of fibrosis with HCC progression was also assessed. Newborn C57/bl6 mice were divided into four groups (n = 12/group): control, PB, DEN, and HCC. Then they were euthanized at different time schedules 2, 4, and 7 months (n = 4/subgroup). Blood and liver tissues were collected for estimation of serum PIIINP and total antioxidant capacity (TAC) liver NOX4 mRNA and protein expression, total oxidative stress, and glutathione (GSH).

RESULTS

The results showed that NOX4 protein expression increased in the first months of HCC induction. Accordingly, liver NOX4-specific mRNA was substantially elevated (2.4 fold). Circulating fibrosis marker, the PIIINP levels together with total oxidative stress increased during HCC induction. TAC and GSH were increased over time during HCC induction.

CONCLUSIONS

Based on the sequential changes observed following HCC induction by DEN, we conclude that increased expression of NOX4 in the liver precedes other changes such as other oxidative stress factors and fibrosis markers during HCC progression.

Reproducible extracellular matrices for tumor organoid culture: challenges and opportunities

Tumor organoid models have emerged as valuable 3D in vitro systems to study cancer behavior in a physiologically relevant environment. The composition and architecture of the extracellular matrix (ECM) play critical roles in tumor organoid culture by influencing the tumor microenvironment and tumor behavior. Traditional matrices such as Matrigel and collagen, have been widely used, but their batch-to-batch variability and limited tunability hinder their reproducibility and broader applications. To address these challenges, researchers have turned to synthetic/engineered matrices and biopolymer-based matrices, which offer precise tunability, reproducibility, and chemically defined compositions. However, these matrices also present challenges of their own. In this review, we explore the significance of ECMs in tumor organoid culture, discuss the limitations of commonly used matrices, and highlight recent advancements in engineered/synthetic matrices for improved tumor organoid modeling.

Altered extracellular matrix structure and elevated stiffness in a brain organoid model for disease

The viscoelastic properties of tissues influence their morphology and cellular behavior, yet little is known about changes in these properties during brain malformations. Lissencephaly, a severe cortical malformation caused by LIS1 mutations, results in a smooth cortex. Here, we show that human-derived brain organoids with LIS1 mutation exhibit increased stiffness compared to controls at multiple developmental stages. This stiffening correlates with abnormal extracellular matrix (ECM) expression and organization, as well as elevated water content, measured by diffusion-weighted MRI. Short-term MMP9 treatment reduces both stiffness and water diffusion levels to control values. Additionally, a computational microstructure mechanical model predicts mechanical changes based on ECM organization. These findings suggest that LIS1 plays a critical role in ECM regulation during brain development and that its mutation leads to significant viscoelastic alterations.

Modulating biomechanical and integrating biochemical cues to foster adaptive remodeling of tissue engineered matrices for cardiovascular implants

Cardiovascular disease remains one of the leading causes of mortality in the Western world. Congenital heart disease affects nearly 1 % of newborns, with approximately one-fourth requiring reconstructive surgery during their lifetime. Current cardiovascular replacement options have significant limitations. Their inability to grow poses particular challenges for pediatric patients. Tissue Engineered Matrix (TEM)-based in situ constructs, with their self-repair and growth potential, offer a promising solution to overcome the limitations of current clinically used replacement options. Various functionalization strategies, involving the integration of biomechanical or biochemical components to enhance biocompatibility, have been developed for Tissue Engineered Vascular Grafts (TEVG) and Tissue Engineered Heart Valves (TEHV) to foster their capacity for in vivo remodeling. In this review, we present the current state of clinical translation for TEVG and TEHV, and provide a comprehensive overview of biomechanical and biochemical functionalization strategies for TEVG and TEHV. We discuss the rationale for functionalization, the implementation of functionalization cues in TEM-based TEVG and TEHV, and the interrelatedness of biomechanical and biochemical cues in the in vivo response. Finally, we address the challenges associated with functionalization and discuss how interdisciplinary research, especially when combined with in silico models, could enhance the translation of these strategies into clinical applications. STATEMENT OF SIGNIFICANCE: Cardiovascular disease remains one of the leading causes of mortality, with current replacements being unable to grow and regenerate. In this review, we present the current state of clinical translation for tissue engineered vascular grafts (TEVG) and heart valves (TEHV). Particularly, we discuss the rationale and implementation for functionalization cues in tissue engineered matrix-based TEVGs and TEHVs, and for the first time we introduce the interrelatedness of biomechanical and biochemical cues in the in-vivo response. These insights pave the way for next-generation cardiovascular implants that promise better durability, biocompatibility, and growth potential. Finally, we address the challenges associated with functionalization and discuss how interdisciplinary research, especially when combined with in silico models, could enhance the translation of these strategies into clinical applications .

ASTROCYTES AND ALCOHOL THROUGHOUT THE LIFESPAN

Evidence for involvement of astrocytes in several neurodegenerative disorders and in drug addiction has been emerging over the last two decades, but only in recent years have astrocytes been investigated for their roles in alcohol use disorder (AUD). As a result, there is a need to evaluate existing preclinical literature supporting involvement of astrocytes in the effects of alcohol exposure. Here we review emerging evidence about responses of astrocytes to alcohol, and the contributions of astrocytes to the development of AUD. We review studies of single-cell RNA sequencing with a focus on alcohol and astrocyte heterogeneity, astrocyte reactivity, and the role of astrocytes in remodeling the extracellular matrix. Effects of alcohol on astrocyte-modulated synaptic transmission are also discussed emphasizing studies never reviewed before. Since astrocytes play essential roles in brain development, we review recent research on the role of astrocytes in fetal alcohol spectrum disorders (FASD) which may also shed light on fetal development of psychiatric disorders that have a high prevalence in individuals affected by FASD. Finally, this review highlights gaps in knowledge about astrocyte biology and alcohol that need further research. Particularly, the dire need to identify astrocyte subpopulations and molecules that are susceptible to alcohol exposure and may be targets for therapeutic intervention.

CCDC80 Protects against Aortic Dissection and Rupture by Maintaining the Contractile Smooth Muscle Cell Phenotype

Aortic dissection (AD) is a life-threatening medical emergency characterized by adverse vascular remodeling. Coiled-coil domain-containing protein 80 (CCDC80) plays an essential role in regulating cardiovascular remodeling. This study aims to define the role of CCDC80 in the formation and development of AD. Significant downregulation of CCDC80 in vascular smooth muscle cell (VSMC) in human and mouse AD is identified. Then, CCDC80 knockout mice (CCDC80-/-) and VSMC-specific CCDC80 knockout mice (CCDC80fl/fl SM22α Cre+) treated with angiotensin II (Ang II) or Ang II combined with β-aminopropionitrile monofumarate (BAPN) frequently develop AD with higher frequency and severity, accompanied by severe elastin fragmentation and collagen deposition. Mechanistically, CCDC80 interacts with JAK2, and CCDC80 deficiency promotes VSMC phenotype switching, proliferation, and migration as well as matrix metalloproteinase production by activating the JAK2/STAT3 signaling pathway. Moreover, the JAK2/STAT3 pathway-specific inhibitor ameliorates adverse vascular remodeling and reduces AD formation in CCDC80-knockout mice by mitigating VSMC phenotype switching. In conclusion, CCDC80 deficiency exacerbates the progression of events leading to AD by activating the JAK2/STAT3 pathway involved in regulating the phenotype switching and function of VSMCs. These findings highlight that CCDC80 is a potential key target for the prevention and treatment of AD.

Induction of cardiac fibulin-4 protects against pressure overload-induced cardiac hypertrophy and heart failure

The prevailing view of fibulin-4 deficient mice is that the cardiac phenotype is the result of aortic and/or valvular disease. In the present study, we have tested whether the cardiac phenotype is, at least in part, the consequence of primary cardiac effects of fibulin-4. We have found fibulin-4 expression to be activated throughout the myocardium in wildtype (fibulin-4+/+) C57Bl/6J;129 Sv mice subjected to transverse aortic constriction (TAC). In contrast, haploinsufficient fibulin-4+/R mice exposed to severe TAC do not show this increase in myocardial fibulin-4 expression, but display altered physical properties of myocardial tissue. Moreover, TAC-induced cardiac fibrosis, pulmonary congestion, and mortality are aggravated in fibulin-4+/R mice. In vitro investigations of myocardial tissue show that fibulin-4 deficiency results in cardiomyocyte hypertrophy, and a decreased beating frequency and contractile force. In conclusion, we demonstrate functions for fibulin-4 in cardiac homeostasis and show that reduced fibulin-4 expression drives myocardial disease in response to cardiac pressure overload, independent of aortic valvular pathology.

Hydrogels with programmed spatiotemporal mechanical cues for stem cell-assisted bone regeneration

Hydrogels are extensively utilized in stem cell-based tissue regeneration, providing a supportive environment that facilitates cell survival, differentiation, and integration with surrounding tissues. However, designing hydrogels for regenerating hard tissues like bone presents significant challenges. Here, we introduce macroporous hydrogels with spatiotemporally programmed mechanical properties for stem cell-driven bone regeneration. Using liquid-liquid phase separation and interfacial supramolecular self-assembly of protein fibres, the macroporous structure of hydrogels provide ample space to prevent contact inhibition during proliferation. The rigid protein fibre-coated pore shell provides sustained mechanical cues for guiding osteodifferentiation and protecting against mechanical loads. Temporally, the hydrogel exhibits tunable degradation rates that can synchronize with new tissue deposition to some extent. By integrating localized mechanical heterogeneity, macroporous structures, surface chemistry, and regenerative degradability, we demonstrate the efficacy of these stem cell-encapsulated hydrogels in rabbit and porcine models. This marks a substantial advancement in tailoring the mechanical properties of hydrogels for stem cell-assisted tissue regeneration.

NELL2, a novel osteoinductive factor, regulates osteoblast differentiation and bone homeostasis through fibronectin 1/integrin-mediated FAK/AKT signaling

Neural EGFL-like 2 (NELL2) is a secreted protein known for its regulatory functions in the nervous and reproductive systems, yet its role in bone biology remains unexplored. In this study, we observed that NELL2 was diminished in the bone of aged and ovariectomized (OVX) mice, as well as in the serum of osteopenia and osteoporosis patients. In vitro loss-of-function and gain-of-function studies revealed that NELL2 facilitated osteoblast differentiation and impeded adipocyte differentiation from stromal progenitor cells. In vivo studies further demonstrated that the deletion of NELL2 in preosteoblasts resulted in decreased cancellous bone mass in mice. Mechanistically, NELL2 interacted with the FNI-type domain located at the C-terminus of Fibronectin 1 (Fn1). Moreover, we found that NELL2 activated the focal adhesion kinase (FAK)/AKT signaling pathway through Fn1/integrin β1 (ITGB1), leading to the promotion of osteogenesis and the inhibition of adipogenesis. Notably, administration of NELL2-AAV was found to ameliorate bone loss in OVX mice. These findings underscore the significant role of NELL2 in osteoblast differentiation and bone homeostasis, suggesting its potential as a therapeutic target for managing osteoporosis.

Nonlinear behavior of stochastic athermal fiber networks with elastic-plastic fibers

Stochastic fiber networks form the structural component of network materials, which are broadly encountered in engineering and biology. Apparent elastic-plastic behavior, characterized by a yield point and softening at larger strains, is observed in some of these materials. A range of mechanisms, some of which being unrelated to fiber plasticity, may cause this behavior. In this work we investigate network plasticity caused by the plastic deformation of fibers and develop a comprehensive perspective on its relationship with network structural parameters. We determine the scaling of the yield stress and yield strain with network parameters emphasizing differences between the affine and non-affine deformation regimes. The non-linear response of the network is more complex when fiber plasticity takes place than in the purely elastic case. We describe four non-linear regimes and their dependence on network parameters. Further, we evaluate the dissipation and residual strains resulting upon loading-unloading cycles for a variety of networks and discuss design strategies for maximizing energy dissipation. Finally, we provide guidelines for the interpretation of experimental results and discuss ways to distinguish between various mechanisms that may cause a yield point and apparent elastic-plastic behavior.

Dynamics of compartment-specific proteomic landscapes of hepatotoxic and cholestatic models of liver fibrosis

Accumulation of extracellular matrix (ECM) in liver fibrosis is associated with changes in protein abundance and composition depending upon etiology of the underlying liver disease. Current efforts to unravel etiology-specific mechanisms and pharmacological targets rely on several models of experimental fibrosis. Here, we characterize and compare dynamics of hepatic proteome remodeling during fibrosis development and spontaneous healing in experimental mouse models of hepatotoxic (carbon tetrachloride [CCl4] intoxication) and cholestatic (3,5-diethoxycarbonyl-1,4-dihydrocollidine [DDC] feeding) injury. Using detergent-based tissue extraction and mass spectrometry, we identified compartment-specific changes in the liver proteome with detailed attention to ECM composition and changes in protein solubility. Our analysis revealed distinct time-resolved CCl4 and DDC signatures, with identified signaling pathways suggesting limited healing and a potential for carcinogenesis associated with cholestasis. Correlation of protein abundance profiles with fibrous deposits revealed extracellular chaperone clusterin with implicated role in fibrosis resolution. Dynamics of clusterin expression was validated in the context of human liver fibrosis. Atomic force microscopy of fibrotic livers complemented proteomics with profiles of disease-associated changes in local liver tissue mechanics. This study determined compartment-specific proteomic landscapes of liver fibrosis and delineated etiology-specific ECM components, providing thus a foundation for future antifibrotic therapies.

Can the Tumor Microenvironment Alter Ion Channels? Unraveling Their Role in Cancer

Neoplastic cells are characterized by metabolic reprogramming, known as the Warburg effect, in which glucose metabolism is predominantly directed toward aerobic glycolysis, with reduced mitochondrial oxidative phosphorylation and increased lactate production even in the presence of oxygen. This phenomenon provides cancer cells with a proliferative advantage, allowing them to rapidly produce energy (in the form of ATP) and generate metabolic intermediates necessary for the biosynthesis of macromolecules essential for cell growth. It is important to understand the role of ion channels in the tumor context since they participate in various physiological processes and in the regulation of the tumor microenvironment. These changes may contribute to the development and transformation of cancer cells, as well as affect the communication between cells and the surrounding microenvironment, including impaired or altered expression and functionality of ion channels. Therefore, the aim of this review is to elucidate the impact of the tumor microenvironment on the electrical properties of the cellular membranes in several cancers as a possible therapeutic target.

AAV-Sparcl1 promotes hair cell regeneration by increasing supporting cell plasticity

Sensorineural hearing deficiency caused by hair cell damage represents a prevalent sensory deficit disorder. In mammals, age-related reduction in plasticity of inner ear supporting cells (recognized as hair cell precursors) compromises their trans-differentiation capacity, resulting in impaired spontaneous hair cell regeneration post-injury. Therapeutic reprogramming of supporting cells to functionally replace damaged hair cells has emerged as a promising strategy for sensorineural hearing loss treatment. In this study, we demonstrate that the secretory protein Sparcl1 enhances supporting cell reprogramming and hair cell regeneration in both in vitro and in vivo models. Through the adeno-associated virus (AAV)-mediated overexpression system, we successfully achieved in vivo expansion of inner ear organoids accompanied by hair cell differentiation. RNA-seq analysis revealed that Sparcl1 overexpression stimulates supporting cell proliferation via follistatin (Fst) activation and extracellular matrix (ECM) remodeling. Notably, both AAV-ie-Sparcl1 delivery and recombinant Sparcl1 protein administration effectively induced supporting cell differentiation into hair cells in vivo. Collectively, our findings establish Sparcl1 as a potent positive regulator of hair cell regeneration and elucidate mechanisms by which secretory proteins regulate supporting cell plasticity.

Osteogenic differentiation of mesenchymal stem cell on poly sorbitol sebacate scaffold under shear stress in a bioreactor

Mechanical loading plays a pivotal role in regulating bone anabolic processes. Understanding the optimal mechanical loading parameters for cellular responses is critical for advancing strategies in orthopedic bioreactor-based bone tissue engineering. This study developed a poly (sorbitol sebacate) (PSS) filmscaffold with a sorbitol-to-sebacic acid molar ratio of 1:4. The scaffold underwent extensive characterization, including physical and mechanical property evaluations, biocompatibility assessments, and cell adhesion analysis. The Young's modulus of the PSS polymer was determined to be 6.81 ± 0.44 MPa under dry conditions, 6.37 ± 1.09 MPa in a wet state, and 6.38 ± 0.71 MPa after ethanol washing (70 %). The average contact angle of the PSS film was measured at 88.806 ± 1.644°, indicating moderate hydrophilicity. To investigate the osteogenic potential, a fluid flow inducing a shear stress of 1 Pa at a frequency of 1 Hz was applied to mesenchymal stem cells (MSCs) cultured on the PSS scaffold. Cells were exposed to dynamic fluid flow for one hour daily on days 4, 5, 6, and 7 of culture, followed by a static culture period of 14 days. The expression of osteogenic differentiation markers, including osteopontin (OPN), osteocalcin (OCN), type I collagen, and calcium deposition, was significantly elevated under dynamic conditions compared to static culture. This study highlights the importance of mechanical stimulation in enhancing MSC osteogenesis and underscores the osteoconductive properties of the PSS scaffold. These findings provide valuable insights into scaffold design and mechanical loading strategies for laboratory-based bone tissue engineering applications.

Matrisome analysis of NSCLC unveils clinically-important cancer-associated extracellular matrix changes

INTRODUCTION

Non-small cell lung carcinoma (NSCLC), comprising adenocarcinoma (LUAD) and squamous cell carcinoma (LUSC), is characterized by an active desmoplastic stroma with an accumulation of extracellular matrix (ECM) proteins. ECM remodeling is a key feature of cancer progression, but the identification of specific therapeutic targets within this compartment remains challenging. Recent studies suggest a link between increased desmoplastic stroma and malignancy in NSCLC, the role of ECM proteins in disease pathogenesis remains unclear.

METHODS

We analyzed an exploratory cohort of Pan-Cancer Atlas and a study cohort to identify differentially expressed ECM proteins. Our focus was on fibrillar components (elastin, fibrillin, collagens), glycosaminoglycans (chondroitin sulfate and heparan sulfate), and matricellular proteins (SPARC). Bioinformatics analysis highlighted matrix proteins that modulate ECM functionality and structure, potentially serving as biomarkers and/or therapeutic targets.

RESULTS

Adenocarcinomas exhibited an ECM enriched with abnormal elastin, chondroitin sulfate, and SPARC. Collagen IV expression in the basement membrane was reduced, while collagen III and V were prominent around tumors. LUSC showed more fibrotic ECM, leading to a stiffer microenvironment. While LUSC's basement membrane may be fragmented, it often retains more intact collagen IV compared to LUAD. High elastin expression in LUAD correlated with smaller tumors (P = 0.022), while fibrillin-2 expression was linked to T1 stage (P = 0.035) and pathological stage I (P = 0.014). In LUSC, elastin expression correlated with negative lymph nodes (P = 0.037). SPARC was an independent factor for overall survival for both subtypes (P < 0.05).

CONCLUSION

This study provides insights into matrix changes in NSCLC and identifies promising candidates for targeted therapies.

Deciphering the Matrisome: Extracellular Matrix Remodeling in Liver Cirrhosis and Hepatocellular Carcinoma

Liver cirrhosis and hepatocellular carcinoma (HCC) are major public health concerns due to their high morbidity and mortality rates. The liver, a vital organ for metabolism, detoxification, and homeostasis, depends on the matrisome, a complex and dynamic network of extracellular matrix (ECM) components for maintaining structural and functional integrity. Chronic liver inflammation, induced by factors such as alcohol abuse, viral hepatitis, and non-alcoholic fatty liver disease, leads to fibrosis and cirrhosis, progressing to HCC. The matrisome, composed of ECM proteins including collagen, fibronectin, and laminin, plays a critical role in regulating tissue homeostasis, cell signaling, and tissue repair. Dysregulation of ECM components contributes to the pathogenesis of both liver cirrhosis and cancer. In cirrhosis, matrisome alterations are characterized by excessive ECM deposition and fibrosis, which disrupt the liver's architecture and impair its function. Activated hepatic stellate cells (HSCs) are the principal mediators of fibrosis, producing large quantities of ECM components. In liver cancer, matrisome remodeling facilitates tumorigenesis by promoting cancer cell proliferation, invasion, and metastasis. The tumor microenvironment, shaped by ECM alterations, further supports tumor growth and dissemination. Matrix metalloproteinases (MMPs) play a pivotal role in ECM degradation, fibrosis progression, and tumor invasion, while tissue inhibitors of metalloproteinases (TIMPs) modulate MMP activity. A comprehensive understanding of the molecular mechanisms that link matrisome alterations with the progression from cirrhosis to liver cancer is essential for identifying novel diagnostic and therapeutic targets. This review highlights the dynamic responses of the hepatic matrisome to both acute and chronic insults, emphasizing the complex interplay between ECM components, cellular behavior, and disease progression. Elucidating these interactions may inform strategies aimed at improving clinical outcomes for patients with liver cirrhosis and HCC.

Tissue-specific extracellular matrix for the larger-scaled expansion of spinal cord organoids

Spinal cord organoids (SCOs) are in vitro models that faithfully recapitulate the basic tissue architecture and cell types of the spinal cord and play a crucial role in developmental studies, disease modeling, and drug screening. Physiological cues are required for proliferation and differentiation during SCO culture. However, commonly used basement membrane matrix products, such as Matrigel®, lack tissue-specific biophysical signals. The current study utilizes decellularization process to fabricate tissue-derived hydrogel from porcine spinal cord tissue that retain intrinsic matrix components. This gel system supported an expanded neuroepithelial scale and enhanced ventral recognition patterns during SCO cultivation. Based on the characteristics of the enlarged aggregate size, a technical system for SCO cutting and subculture are proposed to improve the economic feasibility. Finally, the advantage of S-gel in maintaining neurite outgrowth are also found, which suggests its potential application in neural-related microphysiological systems.

Telomerase reverse transcriptase gene knock-in unleashes enhanced longevity and accelerated damage repair in mice

While previous research has demonstrated the therapeutic efficacy of telomerase reverse transcriptase (TERT) overexpression using adeno-associated virus and cytomegalovirus vectors to combat aging, the broader implications of TERT germline gene editing on the mammalian genome, proteomic composition, phenotypes, lifespan extension, and damage repair remain largely unexplored. In this study, we elucidate the functional properties of transgenic mice carrying the Tert transgene, guided by precise gene targeting into the Rosa26 locus via embryonic stem (ES) cells under the control of the elongation factor 1α (EF1α) promoter. The Tert knock-in (TertKI) mice harboring the EF1α-Tert gene displayed elevated telomerase activity, elongated telomeres, and extended lifespan, with no spontaneous genotoxicity or carcinogenicity. The TertKI mice showed also enhanced wound healing, characterized by significantly increased expression of Fgf7, Vegf, and collagen. Additionally, TertKI mice exhibited robust resistance to the progression of colitis induced by dextran sodium sulfate (DSS), accompanied by reduced expression of disease-deteriorating genes. These findings foreshadow the potential of TertKI as an extraordinary rejuvenation force, promising not only longevity but also rejuvenation in skin and intestinal aging.

The solid tumor microenvironment and related targeting strategies: a concise review

The malignant tumor is a serious disease threatening human life. Increasing studies have confirmed that the tumor microenvironment (TME) is composed of a variety of complex components that precisely regulate the interaction of tumor cells with other components, allowing tumor cells to continue to proliferate, resist apoptosis, evade immune surveillance and clearance, and metastasis. However, the characteristics of each component and their interrelationships remain to be deeply understood. To target TME, it is necessary to deeply understand the role of various components of TME in tumor growth and search for potential therapeutic targets. Herein, we innovatively classify the TME into physical microenvironment (such as oxygen, pH, etc.), mechanical microenvironment (such as extracellular matrix, blood vessels, etc.), metabolic microenvironment (such as glucose, lipids, etc.), inflammatory microenvironment and immune microenvironment. We introduce a concise but comprehensive classification of the TME; depict the characteristics of each component in TME; summarize the existing methods for detecting each component in TME; highlight the current strategies and potential therapeutic targets for TME; discuss current challenges in presenting TME and its clinical applications; and provide our prospect on the future research direction and clinical benefits of TME.

Advancing humanized 3D tumor modeling using an open access xeno-free medium

Despite limitations like poor mimicry of the human cell microenvironment, contamination risks, and batch-to-batch variation, cell culture media with animal-derived components such as fetal bovine serum (FBS) have been used in vitro for decades. Moreover, a few reports have used animal-product-free media in advanced high throughput three-dimensional (3D) models that closely mimic in vivo conditions. To address these challenges, we combined a high throughput 3D model with an open access, FBS-free chemically-defined medium, Oredsson Universal Replacement (OUR) medium, to create a more realistic 3D in vitro drug screening system. To reach this goal, we report the gradual adaptation procedure of three cell lines: human HeLa cervical cancer cells, human MCF-7 breast cancer cells, and cancer-associated fibroblasts (CAFs) from FBS-supplemented medium to OUR medium, while closely monitoring cell attachment, proliferation, and morphology. Our data based on cell morphology studies with phase contrast and real-time live imaging demonstrates a successful adaptation of cells to proliferate in OUR medium showing sustained growth kinetics and maintaining population doubling time. The morphological analysis demonstrates that HeLa and MCF-7 cells displayed altered cell morphology, with a more spread-out cytoplasm and significantly lower circularity index, while CAFs remained unaffected when grown in OUR medium. 3D fiber scaffolds facilitated efficient cell distribution and ingrowth when grown in OUR medium, where cells expand and infiltrate into the depths of 3D scaffolds. Drug toxicity evaluation of the widely used anti-cancer drug paclitaxel (PTX) revealed that cells grown in 3D cultures with OUR medium showed significantly lower sensitivity to PTX, which was consistent with the FBS-supplemented medium. We believe this study opens the way and encourages the scientific community to use animal product-free cell culture medium formulations for research and toxicity testing.

Integrin α11β1 as a Key Collagen Receptor in Human Skin Dermis: Insight into Fibroblast Function and Skin Dermal Aging

Collagen-binding integrins play a crucial role in facilitating fibroblast-collagen interactions and regulating cellular functions. In this study, we identified that among 4 collagen-binding integrins, integrin α11 was the predominant type in human skin dermal fibroblasts and that loss of integrin α11 expression contributed to skin dermal aging. Integrin α11β1 was critical for regulating fibroblast-collagen interactions, including cell adhesion, spreading, morphology, mechanical tension, and the production of collagenous extracellular matrix. TGF-β was recognized as the primary regulator of integrin α11 expression. Notably, dermal fibroblasts in aged human skin demonstrated impaired TGF-β signaling, which coincided with a loss of integrin α11 expression, whereas the expression of other collagen-binding integrins remained unchanged. Similarly, in senescent dermal fibroblasts in vitro, impaired TGF-β signaling was associated with a significant reduction in integrin α11 expression, whereas other collagen-binding integrins were upregulated or unaffected. Furthermore, collapsed dermal fibroblasts, a key characteristic of dermal fibroblasts in aged human skin, specifically downregulated integrin α11, whereas other collagen-binding integrins were upregulated or remained unchanged. These findings suggest a negative feedback loop in which an impaired TGF-β-integrin α11β1 axis and fibroblast collapse promote dermal aging in human skin. This self-reinforcing cycle reflects the progressive and unidirectional nature of biological aging.

Exercise and tissue fibrosis: recent advances in therapeutic potential and molecular mechanisms

Tissue fibrosis represents an aberrant repair process, occurring because of prolonged injury, sustained inflammatory response, or metabolic disorders. It is characterized by an excessive accumulation of extracellular matrix (ECM), resulting in tissue hardening, structural remodeling, and loss of function. This pathological phenomenon is a common feature in the end stage of numerous chronic diseases. Despite the advent of novel therapeutic modalities, including antifibrotic agents, these have only modest efficacy in reversing established fibrosis and are associated with adverse effects. In recent years, a growing body of research has demonstrated that exercise has significant benefits and potential in the treatment of tissue fibrosis. The anti-fibrotic effects of exercise are mediated by multiple mechanisms, including direct inhibition of fibroblast activation, reduction in the expression of pro-fibrotic factors such as transforming growth factor-β (TGF-β) and slowing of collagen deposition. Furthermore, exercise has been demonstrated to assist in maintaining the dynamic equilibrium of tissue repair, thereby indirectly reducing tissue damage and fibrosis. It can also help maintain the dynamic balance of tissue repair by improving metabolic disorders, exerting anti-inflammatory and antioxidant effects, regulating cellular autophagy, restoring mitochondrial function, activating stem cell activity, and reducing cell apoptosis, thereby indirectly alleviating tissue. This paper presents a review of the therapeutic potential of exercise and its underlying mechanisms for the treatment of a range of tissue fibrosis, including cardiac, pulmonary, renal, hepatic, and skeletal muscle. It offers a valuable reference point for non-pharmacological intervention strategies for the comprehensive treatment of fibrotic diseases.

Extracellular Matrix Stiffness: Mechanotransduction and Mechanobiological Response-Driven Strategies for Biomedical Applications Targeting Fibroblast Inflammation

The extracellular matrix (ECM) is a dynamic network providing mechanical and biochemical cues that regulate cellular behavior. ECM stiffness critically influences fibroblasts, the primary ECM producers, particularly in inflammation and fibrosis. This review explores the role of ECM stiffness in fibroblast-driven inflammation and tissue remodeling, focusing on the physicochemical and biological mechanisms involved. Engineered materials, hydrogels, and polydimethylsiloxane (PDMS) are highlighted for replicating tissue-specific stiffness, enabling precise control over cell-matrix interactions. The surface functionalization of substrate materials, including collagen, polydopamine, and fibronectin, enhances bioactivity and fibroblast adhesion. Key mechanotransduction pathways, such as integrin signaling and YAP/TAZ activation, are related to regulating fibroblast behaviors and inflammatory responses. The role of fibroblasts in driving chronic inflammatory diseases emphasizes their therapeutic potentials. Advances in ECM-modifying strategies, including tunable biomaterials and hydrogel-based therapies, are explored for applications in tissue engineering, drug delivery, anti-inflammatory treatments, and diagnostic tools for the accurate diagnosis and prognosis of ECM stiffness-related inflammatory diseases. This review integrates mechanobiology with biomedical innovations, providing a comprehensive prognosis of fibroblast responses to ECM stiffness and outlining future directions for targeted therapies.

Intercellular Communication Network of CellChat Uncovers Mechanisms of Kidney Fibrosis Based on Single-Cell RNA Sequencing

BACKGROUND

Chronic kidney disease (CKD) is a global health concern, with renal fibrosis being a major pathological feature. Empagliflozin (Empa), a sodium-glucose co-transporter-2 inhibitor, has shown promise in protecting the kidney. This study aimed to investigate the effects of Empa on renal fibrosis in a nondiabetic CKD model and to elucidate the underlying mechanisms.

METHODS

We established a CKD model using 5/6 nephrectomy (5/6 Nx) rats and divided them into three groups: placebo-treated sham surgery rats, placebo-treated 5/6 Nx rats, and Empa-treated 5/6 Nx rats. Kidney function was assessed by measuring blood urea nitrogen, serum creatinine, and urinary albumin-to-creatinine ratio. Renal fibrosis was evaluated histologically. Single-cell RNA sequencing (scRNA-seq) was performed to analyze intercellular communication networks and identify alterations in ligand-receptor pairs and signaling pathways involved in fibrosis.

RESULTS

Empa treatment significantly improved kidney function and reduced renal interstitial fibrosis in 5/6 Nx rats. scRNA-seq revealed that Empa modulated the TGF-β signaling pathway, inhibited intercellular communication, and reduced the expression of fibrotic genes such as COLLAGEN, FN1, THBS, and LAMININ. Furthermore, Empa downregulated GRN gene expression, weakened signal transmission in the MIF pathway, consequently reduced the interaction between M2 macrophages and other cell types, such as endothelial cells, fibroblasts, and mesangial cells.

CONCLUSION

This study elucidates the potential mechanisms by which Empa slows the progression of renal fibrosis in nondiabetic CKD. By reducing the number of M2 macrophages and inhibiting signal transduction in both pro-inflammatory and fibrotic pathways, Empa modulates the intercellular communication network in renal cells, offering a promising therapeutic strategy for CKD management.

Fibronectin matrix assembly at a glance

The organization and mechanics of extracellular matrix (ECM) protein polymers determine tissue structure and function. Secreted ECM components are assembled into polymers via a cell-mediated process. The specific mechanisms that cells use for assembly are crucial for generating tissue-appropriate matrices. Fibronectin (FN) is a ubiquitous and abundant ECM protein that is assembled into a fibrillar matrix by a receptor-mediated process, and the FN matrix provides a foundation for incorporation of many other proteins into the ECM. In this Cell Science at a Glance article and the accompanying poster, we describe the domain organization of FN and the events that initiate and propagate a stable insoluble network of FN fibrils. We also discuss intracellular pathways that regulate FN assembly and the impact of changes in assembly on disease progression.

Machine learning identifies remodeling patterns in human lung extracellular matrix

Organ function depends on the three-dimensional integrity of the extracellular matrix (ECM). The structure resulting from the location and association of ECM components is a central regulator of cell behavior, but a dearth of matrix-specific analysis keeps it unresolved. Here, we deploy a high-resolution, 3D ECM mapping method and design a machine-learning powered pipeline to detect and characterize ECM architecture during health and disease. We deploy these tools in the human lung, an organ heavily dependent on ECM structure that can host diseases with different histopathologies. We analyzed segments from healthy, emphysema, usual interstitial pneumonia, sarcoidosis, and COVID-19 patients, and produced a remodeling signature per disease and a health/disease probability map from which we inferred the architecture of healthy and diseased ECM. Our methods demonstrate that exaggerated matrix deposition, or fibrosis, is not a single phenomenon, but a series of disease-specific alterations. STATEMENT OF SIGNIFICANCE: The extracellular matrix, or ECM, is the foremost biomaterial. It shapes and supports all tissues while regulating all cells. ECM structure is intricate, yet precise: each organ, at every stage, has a specific ECM structure. During disease, tissues suffer from structural changes that accelerate and perpetuate illness by dysregulating cells. Both healthy and diseased ECM structures are of great biomedical importance, but surprisingly, they have not been mapped in detail. Here, we present a method that combines tissue engineering with machine learning to reveal, map and analyze ECM structures, applied it to pulmonary diseases that kill millions every year. This method can bring objectivity and a higher degree of confidence into the diagnosis of pulmonary disease. In addition the amount of tissue needed for a firm diagnosis may be much smaller than required for manual microscopy evaluation.

A novel approach for engineering DHCM/GelMA microgels: application in hepatocellular carcinoma cell encapsulation and chemoresistance research

Liver cancer, a highly aggressive malignancy, continues to present significant challenges in therapeutic management due to its pronounced chemoresistance. This resistance, which undermines the efficacy of conventional chemotherapy and targeted therapies, is driven by multifaceted mechanisms, with increasing emphasis placed on the protective role of the tumor microenvironment (TME). The hepatocellular carcinoma extracellular matrix (ECM), a primary non-cellular component of the TME, has emerged as a critical regulator in cancer progression and drug resistance, particularly in hepatocellular carcinoma cell (HCC). In this study, a hybrid biomimetic hydrogel was engineered by integrating decellularized hepatocellular carcinoma matrix (DHCM) with gelatin methacrylate (GelMA) precursors. This composite DHCM/GelMA hydrogel was designed to replicate the physicochemical and functional properties of the hepatocellular carcinoma ECM, thereby offering a biomimetic platform to explore the interactions between HCCs and their microenvironment. Leveraging a custom-designed microfluidic 3D printing platform, we achieved high-throughput fabrication of HCC-encapsulated DHCM/GelMA microgels, characterized by enhanced uniformity, biocompatibility, and scalability. These microgels facilitated the construction of hepatocellular carcinoma microtissues, which were subsequently employed for chemoresistance studies. Our findings revealed that DHCM/GelMA microgels closely mimic the hepatocellular carcinoma tumor microenvironment, effectively recapitulating key features of ECM-mediated drug resistance. Mechanistic studies further demonstrated that DHCM significantly upregulates the expression of Aquaporin 3 (AQP3) in the encapsulated HCCs. This upregulation potentially activates mTOR signaling-associated autophagy pathways, thereby enhancing chemoresistance in HCCs. These biomimetic models provide a robust and versatile platform for studying the underlying mechanisms of drug resistance and evaluating therapeutic interventions. This innovative approach highlights the potential of DHCM/GelMA microgels as a transformative tool in cancer-associated tissue engineering and anticancer drug screening. By enabling detailed investigations into the role of ECM in chemoresistance, this study contributes to advancing therapeutic research and offers promising strategies to overcome drug resistance, ultimately improving clinical outcomes in liver cancer treatment.

Rapid Fabrication of Tendon-inspired Ultrastrong, Water-rich Hydrogel Fibers: Synergistic Engineering of Cyano-p-aramid Nanofibers and Poly(vinyl alcohol)

Load-bearing fibrous tissues, like tendons, have remarkable strength with high water content (∼60%) due to the anisotropic network of collagen fibers. However, the scalability of biomimetic anisotropic hydrogels is limited by time-intensive fabrication processes involving cross-linking and stretching, often spanning several hours to days. Here, we present a rapid, scalable approach for fabricating tendon-mimetic hydrogel fibers within 1 min using the synergistic engineering of cyano-p-aramid nanofibers (CY-ANFs) and poly(vinyl alcohol) (PVA). Through continuous air-gap spinning, the formation of the anisotropic CY-ANF network drives instant gelation, producing hundreds of meters of hydrogel fibers without additional gelation treatment. From the perspective of properties, the hydrophilic PVA matrix affords flexibility, while the hydrophobic CY-ANF network provides a nonswelling feature and load-bearing ability, resulting in ultrastrong, water-rich hydrogel fibers. These hydrogel fibers exhibit a water content exceeding 80 wt %, along with exceptional strength (∼17.9 MPa), surpassing the mechanical properties of natural tendons (strength and modulus of approximately 10 and 100 MPa, respectively). Lengthy hydrogel fibers are integrated into larger-sized fabrics by knitting or weaving while also possessing strain-sensing capabilities. With excellent biocompatibility, these hydrogel fibers are promising candidates for artificial fibrous tissues and various biotechnological applications.

Bio-orthogonal tuning of matrix properties during 3D cell culture to induce morphological and phenotypic changes

Described herein is a protocol for producing a synthetic extracellular matrix that can be modified in situ during three-dimensional cell culture. The hydrogel platform is established using modular building blocks employing bio-orthogonal tetrazine (Tz) ligation with slow (norbornene, Nb) and fast (trans-cyclooctene, TCO) dienophiles. A cell-laden gel construct is created via the slow, off-stoichiometric Tz/Nb reaction. After a few days of culture, matrix properties can be altered by supplementing the cell culture media with TCO-tagged molecules through the rapid reaction with the remaining Tz groups in the network at the gel-liquid interface. As the Tz/TCO reaction is faster than molecular diffusion, matrix properties can be modified in a spatiotemporal fashion simply by altering the identity of the diffusive species and the diffusion time/path. Our strategy does not interfere with native biochemical processes nor does it require external triggers or a second, independent chemistry. The biomimetic three-dimensional cultures can be analyzed by standard molecular and cellular techniques and visualized by confocal microscopy. We have previously used this method to demonstrate how in situ modulation of matrix properties induces epithelial-to-mesenchymal transition, elicits fibroblast transition from mesenchymal stem cells and regulates myofibroblast differentiation. Following the detailed procedures, individuals with a bachelor's in science and engineering fields can successfully complete the protocol in 4-5 weeks. This protocol can be applied to model tissue morphogenesis and disease progression and it can also be used to establish engineered constructs with tissue-like anisotropy and tissue-specific functions.

Designing lysyl hydroxylase inhibitors for oral submucous fibrosis - Insights from molecular dynamics

Alpha-ketoglutarate (αKG) dependent Lysyl hydroxylase (LH) is a critical enzyme in the post-translational conversion of lysine into hydroxylysine in collagen triple helix and telopeptide regions. Overexpression of LH increases collagen hydroxylation and covalent cross-linkage, causing fibrosis. Currently, no drugs are available to inhibit LH potentially. Virtual screening of the Zinc database was employed to identify new leads. They were docked using Glide. Lead1 complex exhibits a notably superior docking score compared to other leads. This complex hinders iron stabilization by engaging with the HXD..Xn..H motif and competitively inhibiting 2OG binding at the catalytic site via interactions with Cys691 and Arg729 by forming a salt bridge. Molecular dynamics simulations over a 500 ns time scale and molecular mechanics Poisson-Boltzmann surface area calculations illustrate the stable binding of Leads. DCCA analysis finds the coordinated residue motions and the influence of the second coordinating sphere in long-range interactions. In-silico results were validated by quantifying the amount of collagen in zebrafish through histology and hydroxyproline assay. These findings demonstrated a reduction in collagen deposition in the treated samples compared to the positive control. This computational study unveiled insights into how leads may impede collagen lysine hydroxylation and potentially impact collagen-related processes.

Emerging biotechnologies for engineering liver organoids

The engineering construction of the liver has attracted enormous attention. Organoids, as emerging miniature three-dimensional cultivation units, hold significant potential in the biomimetic simulation of liver structure and function. Despite notable successes, organoids still face limitations such as high variability and low maturity. To overcome these challenges, engineering strategies have been established to maintain organoid stability and enhance their efficacy, laying the groundwork for the development of advanced liver organoids. The present review comprehensively summarizes the construction of engineered liver organoids and their prospective applications in biomedicine. Initially, we briefly present the latest research progress on matrix materials that maintain the three-dimensional morphology of organoids. Next, we discuss the manipulative role of engineering technologies in organoid assembly. Additionally, we outline the impact of gene-level regulation on organoid growth and development. Further, we introduce the applications of liver organoids in disease modeling, drug screening and regenerative medicine. Lastly, we overview the current obstacles and forward-looking perspectives on the future of engineered liver organoids. We anticipate that ongoing innovations in engineered liver organoids will lead to significant advancements in medical applications.

Youthful Stem Cell Microenvironments: Rejuvenating Aged Bone Repair Through Mitochondrial Homeostasis Remodeling

Extracellular matrix (ECM) derived from mesenchymal stem cells regulates antioxidant properties and bone metabolism by providing a favorable extracellular microenvironment. However, its functional role and molecular mechanism in mitochondrial function regulation and aged bone regeneration remain insufficiently elucidated. This proteomic analysis has revealed a greater abundance of proteins supporting mitochondrial function in the young ECM (Y-ECM) secreted by young bone marrow-derived mesenchymal stem cells (BMMSCs) compared to the aged ECM (A-ECM). Further studies demonstrate that Y-ECM significantly rejuvenates mitochondrial energy metabolism in adult BMMSCs (A-BMMSCs) through the promotion of mitochondrial respiratory functions and amelioration of oxidative stress. A-BMMSCs cultured on Y-ECM exhibited enhanced multi-lineage differentiation potentials in vitro and ectopic bone formation in vivo. Mechanistically, silencing of silent information regulator type 3 (SIRT3) gene abolished the protective impact of Y-ECM on A-BMMSCs. Notably, a novel composite biomaterial combining hyaluronic acid methacrylate hydrogel microspheres with Y-ECM is developed, which yielded substantial improvements in the healing of bone defects in an aged rat model. Collectively, these findings underscore the pivotal role of Y-ECM in maintaining mitochondrial redox homeostasis and present a promising therapeutic strategy for the repair of aged bone defects.