Matrisome AnalyzeR - a suite of tools to annotate and quantify ECM molecules in big datasets across organisms

Halofuginone Disrupted Collagen Deposition via mTOR-eIF2α-ATF4 Axis to Enhance Chemosensitivity in Ovarian Cancer

The interplay between cancer-associated fibroblasts (CAFs) and extracellular matrix (ECM) mediates progress, metastasis, and therapy resistance. However, strategy of targeting ECM remodeling to enhance chemosensitivity in ovarian cancer remains elusive. Here, a 22-gene matrisome signature predicts chemotherapy response and survival in ovarian cancer. The dense, collagen-rich ECM secreted by CAFs harbors more M2 tumor-associated macrophages (TAMs) than the looser ECM based on single cell RNA-seq (scRNA-seq) of ovarian cancer, suggesting the promising approach of targeting collagen to remodel ECM. An integrated analysis identifies collagen type I alpha 1 chain (COL1A1) as a major component of the ECM that contributes to chemoresistance and poor prognosis, highlighting its potential as a therapeutic target. Halofuginone (HF), a clinically active derivative of febrifugine, is identified as a COL1A1-targeting natural compound by screening the Encyclopedia of Traditional Chinese Medicine (ETCM). Mechanistically, HF inhibits COL1A1 production via the mTOR-eIF2α-ATF4 axis in CAFs. Notably, HF disrupts collagen deposition and promotes CD8+ T cell infiltration, partially via M2-M1 macrophage polarization to enhance chemosensitivity. Overall, the findings suggest that HF combined with chemotherapy is a promising and effective treatment for ovarian cancer.

Time-lapse tryptic digestion: a proteomic approach to improve sequence coverage of extracellular matrix proteins

The extracellular matrix (ECM) is a complex and dynamic meshwork of proteins providing structural support to cells. It also provides biochemical signals governing cellular processes, including proliferation, adhesion, and migration. Alterations of ECM structure and/or composition have been linked to many pathological processes, including cancer and fibrosis. Over the past decade, mass-spectrometry-based proteomics has become the state-of-the-art method to profile the protein composition of ECMs. However, existing methods do not fully capture the broad dynamic range of protein abundances in the ECM. They also do not permit to achieve the high coverage needed to gain finer biochemical on ECM proteoforms (e.g., isoforms, post-translational modifications) and topographical information critical to better understand ECM protein functions. Here, we present the development of a time-lapsed proteomic pipeline using limited tryptic proteolysis and sequential release of peptides over time. This experimental pipeline was combined with data-independent acquisition mass spectrometry and the assembly of a custom matrisome spectral library to enhance peptide-to-spectrum matching. This pipeline shows superior protein identification, peptide-to-spectrum matching, and significantly increased sequence coverage against standard ECM proteomic pipelines. Exploiting the spatio-temporal resolution of this method, we further demonstrate how time-resolved 3-dimensional peptide mapping can identify protein regions differentially susceptible to trypsin, which may aid in identifying protein-protein interaction sites.

SDC4 drives fibrotic remodeling of the intervertebral disc under altered spinal loading

Alterations in physiological loading of the spine are deleterious to intervertebral disc health. The caudal spine region Ca3-6 that experiences increased flexion, showed disc degeneration in young adult mice. Given the role of Syndecan 4 (SDC4), a cell surface heparan sulfate proteoglycan in disc matrix catabolism and mechanosensing, we investigated if deletion could mitigate this loading-dependent phenotype. Notably, at spinal levels Ca3-6, Sdc4- KO mice did not exhibit increased collagen fibril and fibronectin deposition in the NP compartment or showed the alterations in collagen crosslinks observed in wild-type mice. Similarly, unlike wild-type mice, NP cells in Sdc4 -KO mice retained transgelin (TGLN) expression and showed absence of COL X deposition, pointing to the preservation of their notochordal characteristics. Proteomic analysis revealed that NP tissues responded to the abnormal loading by increasing the abundance of proteins associated with extracellular matrix remodeling, chondrocyte development, and contractility. Similarly, downregulated proteins suggested decreased vesicle transport, autophagy-related pathway, and RNA quality control regulation. Notably, NP proteome from Sdc4 KO suggested that increased dynamin-mediated endocytosis, autophagy-related pathway, and RNA and DNA quality control may underscore the protection from increased flexion-induced degeneration. Our study highlights the important role of SDC4 in fine-tuning cellular homeostasis and extracellular matrix production in disc environment subjected to altered loading.

Biological and therapeutic implications of sex hormone-related gene clustering in testicular cancer

BACKGROUND

Gonadotropin dysregulation seems to play a potential role in the carcinogenesis of testicular germ cell tumor (TGCT). The aim of this study was to explore the expression of specific genes related to sex hormone regulation, synthesis, and metabolism in TGCT and to define specific hormonal clusters. Two publicly available databases were used for this analysis (TCGA and GSE99420). By means of hard-threshold regularized KMEANS clustering, we assigned TGCT samples into four clusters defined in respect to different expression of the sex hormone-related genes. We analysed clinical data, protein and gene expression, signaling regarding hormonal clusters. Based on whole-transcriptome gene expression, prediction of anti-cancer drug response was made by RIDGE models.

RESULTS

Cluster #1 (12-16%) consisted primarily of non-seminomatous germ cell tumor (NSGCT), characterized by high expression of PRL, GNRH1, HSD17B2 and SRD5A1. Cluster #2 (42-50%) included predominantly seminomas with high expression of SRD5A3, being highly infiltrated by T and B cells. Cluster #3 (8.3-18%) comprised of NSGCT with high expression of CGA, CYP19A1, HSD17B12, HSD17B1, SHBG. Cluster #4 (23-30%), which consisted primarily of NSGCT with a small fraction of seminomas, was outlined by increased expression of STAR, POMC, CYP11A1, CYP17A1, HSD3B2 and HSD17B3. Elevated fibroblast levels and increased extracellular matrix- and growth factor signaling-related gene signature scores were described in cluster #1 and #3. In the combined model of progression-free survival, S2/S3 tumor marker status, hormonal cluster #1 or #3 and teratoma histology, were independently associated with 25-30% increase of progression risk. Based on the increased receptor tyrosine kinase and growth factor signaling, cluster #1, #3 and #4 were predicted to be sensitive to tyrosine kinase inhibitors, FGFR inhibitors or EGFR/ERBB inhibitors. Cluster #2 and #4 were responsive to compounds interfering with DNA synthesis, cytoskeleton, cell cycle and epigenetics. Response to apoptosis modulators was predicted only for cluster #2.

CONCLUSIONS

Hormonal cluster #1 or #3 is an independent prognostic factor regarding poor progression-free survival. Hormonal cluster assignment also affects the predicted drug response with cluster-dependent susceptibility to specific novel therapeutic compounds.

Unraveling Molecular and Functional Responses Across 3 Lung Injury Models to Expand the Donor Lung Pool

BACKGROUND

Lung transplantation remains hampered by a scarcity of viable donor lungs, partially attributed to donor lung injuries.

METHODS

Three porcine lung injury models were studied: infection-induced using lipopolysaccharide (n = 7), aspiration-induced using endotracheal gastric content (n = 7), and injury using lavage and harmful ventilation (ventilator-induced lung injury; n = 7). Molecular and functional changes from before and after the establishment of lung injury were examined with histopathology, immunohistochemistry, cytokine levels, hemodynamics, and mass spectrometric analysis of lung tissue. The respiratory tract lining fluid was analyzed using exhaled breath particles.

RESULTS

T-cell proliferation and suppression of complement activation were unique to the gastric injury, whereas the ventilator-induced lung injury group displayed a unique activation of monocyte chemotaxis. The lipopolysaccharide injury exhibited an activation of stress response proteins. Alterations in the extracellular matrix, particularly the degradation of collagen type IV and increased elastin expression, were identified as a consistent indicator of acute lung injury. Additionally, increases in exhaled particles and differential expression of proteins in the respiratory tract lining fluid correlated with deteriorating lung function.

CONCLUSIONS

Molecular analysis of the lung indicated distinct key differences and similarities of donor lung injury phenotypes. Analysis of various donor lung injuries suggests a heightened emphasis on the extracellular matrix for the restoration and rejuvenation of damaged donor lungs.

Insoluble proteomics analysis of acute intracranial large vessel occlusive thrombus

BACKGROUND

Acute large vessel occlusion (LVO) stroke is highly prevalent and severe. Despite thrombolytic therapy, many patients experience substantial complications. Understanding the origins, constituents, and pathologic processes involved in thrombus formation in acute intracranial large artery occlusion is crucial.

OBJECTIVES

To identify the characteristics of insoluble proteins from different sources of cerebral thrombus.

METHODS

This study included 13 patients with cardiogenic embolic (CE) thrombus and 15 with large artery atherosclerotic (LAA) thrombus. High-performance liquid chromatography and liquid chromatography-tandem mass spectrometry were used to analyze insoluble proteins in thrombi. Bioinformatics analyses explored differential proteins and associated functional pathways. Least absolute shrinkage and selection operator and random forest identified biomarkers for diagnosing thrombus sources, validated by parallel reaction monitoring.

RESULTS

We constructed an insoluble protein atlas of cerebral thrombi, identifying 6975 insoluble proteins, including 143 extracellular matrix (ECM)-related proteins. The enrichment pathways considerably varied between thrombi from different sources. Inflammation-related pathways, such as acute inflammatory response, along with ECM-related pathways such as laminin interactions, were notably upregulated in LAA compared with CE. Additionally, 2 biomarkers (IDH2 and HSPG2) exhibited strong diagnostic performance (area under the curve = 1) and robustness.

CONCLUSION

In the insoluble proteomics of thrombus, we highlighted the crucial roles of immune responses and ECM proteins in thrombus formation, providing new insights into its mechanisms and potential drug development. Additionally, we identified 2 biomarkers that offer new methods for determining thrombus sources in patients with LVO.

SenPred: a single-cell RNA sequencing-based machine learning pipeline to classify deeply senescent dermal fibroblast cells for the detection of an in vivo senescent cell burden

BACKGROUND

Senescence classification is an acknowledged challenge within the field, as markers are cell-type and context dependent. Currently, multiple morphological and immunofluorescence markers are required. However, emerging scRNA-seq datasets have enabled an increased understanding of senescent cell heterogeneity.

METHODS

Here we present SenPred, a machine-learning pipeline which identifies fibroblast senescence based on single-cell transcriptomics from fibroblasts grown in 2D and 3D.

RESULTS

Using scRNA-seq of both 2D and 3D deeply senescent fibroblasts, the model predicts intra-experimental fibroblast senescence to a high degree of accuracy (> 99% true positives). Applying SenPred to in vivo whole skin scRNA-seq datasets reveals that cells grown in 2D cannot accurately detect fibroblast senescence in vivo. Importantly, utilising scRNA-seq from 3D deeply senescent fibroblasts refines our ML model leading to improved detection of senescent cells in vivo. This is context specific, with the SenPred pipeline proving effective when detecting senescent human dermal fibroblasts in vivo, but not the senescence of lung fibroblasts or whole skin.

CONCLUSIONS

We position this as a proof-of-concept study based on currently available scRNA-seq datasets, with the intention to build a holistic model to detect multiple senescent triggers using future emerging datasets. The development of SenPred has allowed for the detection of an in vivo senescent fibroblast burden in human skin, which could have broader implications for the treatment of age-related morbidities. All code for the SenPred pipeline is available at the following URL: https://github.com/bethk-h/SenPred_HDF .

Engineered nascent living human tissues with unit programmability

Leveraging human cells as materials precursors is a promising approach for fabricating living materials with tissue-like functionalities and cellular programmability. Here we describe a set of cellular units with metabolically engineered glycoproteins that allow cells to tether together to function as macrotissue building blocks and bioeffectors. The generated human living materials, termed as Cellgels, can be rapidly assembled in a wide variety of programmable three-dimensional configurations with physiologically relevant cell densities (up to 108 cells per cm3), tunable mechanical properties and handleability. Cellgels inherit the ability of living cells to sense and respond to their environment, showing autonomous tissue-integrative behaviour, mechanical maturation, biological self-healing, biospecific adhesion and capacity to promote wound healing. These living features also enable the modular bottom-up assembly of multiscale constructs, which are reminiscent of human tissue interfaces with heterogeneous composition. This technology can potentially be extended to any human cell type, unlocking the possibility for fabricating living materials that harness the intrinsic biofunctionalities of biological systems.

Correlation of Pancreatic Laminin Alpha 5 Expression With Clinical Outcomes in Total Pancreatectomy With Islet Autotransplantation

This study examines extracellular matrix (ECM) protein (ECM) expression in chronic pancreatitis (CP) patients and its correlation with graft function after total pancreatectomy with islet autologous transplantation (TPIAT). Pancreatic sections from 29 CP patients undergoing TPIAT were analyzed for ECM including pan-laminin, laminin alpha 5 (LAMA5), collagen IV, and Perlecan by immunohistochemistry and scored by the percentage positive staining area within the whole tissue area. Graft function was monitored by blood glucose and C-peptide levels. Laminin alpha 5 levels in blood plasma were greater in CP. Laminin alpha 5 expression was significantly higher in all CP patient etiological categories including alcoholic, hereditary, idiopathic, Oddi dysfunction, and pancreatic divisum compared to healthy controls. The overall expression of LAMA5 positively correlated with expression of the ECM proteins pan-laminin (R = 0.63, P < 0.001), collagen IV (R = 0.67, P < 0.001), and Perlecan (R = 0.71, P < 0.001). Increased LAMA5 expression was observed within islet endothelial vascular tissue and the peri-islet basal membrane. Increased LAMA5 expression in the pancreas correlated with poor islet isolation yield and posttransplant islet function after 3 months. Increased endothelial expression of LAMA5 and ECM proteins is indicative of progressive damage to the pancreas and correlates with poor graft function after TPIAT.

MatriCom: a scRNA-Seq data mining tool to infer ECM-ECM and cell-ECM communication systems

The ECM is a complex and dynamic meshwork of proteins that forms the framework of all multicellular organisms. Protein interactions within the ECM are critical to building and remodeling the ECM meshwork, while interactions between ECM proteins and cell surface receptors are essential for the initiation of signal transduction and the orchestration of cellular behaviors. Here, we report the development of MatriCom, a web application (https://matrinet.shinyapps.io/matricom) and a companion R package (https://github.com/Izzilab/MatriCom), devised to mine scRNA-Seq datasets and infer communications between ECM components and between different cell populations and the ECM. To impute interactions from expression data, MatriCom relies on a unique database, MatriComDB, that includes over 25,000 curated interactions involving matrisome components, with data on 80% of the ~1,000 genes that compose the mammalian matrisome. MatriCom offers the option to query open-access datasets sourced from large sequencing efforts (Tabula Sapiens, The Human Protein Atlas, HuBMAP) or to process user-generated datasets. MatriCom is also tailored to account for the specific rules governing ECM protein interactions and offers options to customize the output through stringency filters. We illustrate the usability of MatriCom with the example of the human kidney matrisome communication network. Last, we demonstrate how the integration of 46 scRNA-Seq datasets led to the identification of both ubiquitous and tissue-specific ECM communication patterns. We envision that MatriCom will become a powerful resource to elucidate the roles of different cell populations in ECM-ECM and cell-ECM interactions and their dysregulations in the context of diseases such as cancer or fibrosis.

Amniotic Membrane-Derived Multichannel Hydrogels for Neural Tissue Repair

In the pursuit of advancing neural tissue regeneration, biomaterial scaffolds have emerged as promising candidates, offering potential solutions for nerve disruptions. Among these scaffolds, multichannel hydrogels, characterized by meticulously designed micrometer-scale channels, stand out as instrumental tools for guiding axonal growth and facilitating cellular interactions. This study explores the innovative application of human amniotic membranes modified with methacryloyl domains (AMMA) in neural stem cell (NSC) culture. AMMA hydrogels, possessing a tailored softness resembling the physiological environment, are prepared in the format of multichannel scaffolds to simulate native-like microarchitecture of nerve tracts. Preliminary experiments on AMMA hydrogel films showcase their potential for neural applications, demonstrating robust adhesion, proliferation, and differentiation of NSCs without the need for additional coatings. Transitioning into the 3D realm, the multichannel architecture fosters intricate neuronal networks guiding neurite extension longitudinally. Furthermore, the presence of synaptic vesicles within the cellular arrays suggests the establishment of functional synaptic connections, underscoring the physiological relevance of the developed neuronal networks. This work contributes to the ongoing efforts to find ethical, clinically translatable, and functionally relevant approaches for regenerative neuroscience.

Characterization of Amnion-Derived Membrane for Clinical Wound Applications

Human amniotic membrane (hAM), the innermost placental layer, has unique properties that allow for a multitude of clinical applications. It is a common misconception that birth-derived tissue products, such as dual-layered dehydrated amnion-amnion graft (dHAAM), are similar regardless of the manufacturing steps. A commercial dHAAM product, Axolotl Biologix DualGraft™, was assessed for biological and mechanical characteristics. Testing of dHAAM included antimicrobial, cellular biocompatibility, proteomics analysis, suture strength, and tensile, shear, and compressive modulus testing. Results demonstrated that the membrane can be a scaffold for fibroblast growth (cellular biocompatibility), containing an average total of 7678 unique proteins, 82,296 peptides, and 96,808 peptide ion variants that may be antimicrobial. Suture strength results showed an average pull force of 0.2 N per dHAAM sample (equating to a pull strength of 8.5 MPa). Tensile modulus data revealed variation, with wet samples showing 5× lower stiffness than dry samples. The compressive modulus and shear modulus displayed differences between donors (lots). This study emphasizes the need for standardized processing protocols to ensure consistency across dHAAM products and future research to explore comparative analysis with other amniotic membrane products. These findings provide baseline data supporting the potential of amniotic membranes in clinical applications.

Identification of a fibronectin-binding protein signature associated with idiopathic pulmonary fibrosis

The extracellular matrix (ECM) is a critical component of tissue where it provides structural and signaling support to cells. Its dysregulation and accumulation lead to fibrosis, a major clinical challenge underlying many diseases that currently has little effective treatment. An understanding of the key molecular initiators of fibrosis would be both diagnostically useful and provide potential targets for therapeutics. The ECM protein fibronectin (FN) is upregulated in fibrotic conditions and other ECM proteins depend on assembly of a FN foundational ECM for their matrix incorporation. We used cell culture and in vivo models to investigate the role of FN in the progression of lung fibrosis. We confirmed that normal human lung fibroblasts (NHLFs) treated with transforming growth factor-beta (TGF-β) to stimulate fibrotic gene expression significantly increased both FN expression and its assembly into a matrix. We found that levels of alternatively spliced EDA and EDB exons were proportional to the increase in total FN RNA and protein showing that inclusion of these exons is not enhanced by TGF-β stimulation. RNA-sequencing identified 43 core matrisome genes that were significantly up- or down-regulated by TGF-β treatment and a Luminex immunoassay demonstrated increased levels of ECM proteins in conditioned medium of TGF-β-treated NHLFs. Interestingly, among the regulated core matrisome genes, 16 encode known FN-binding proteins and, of these, insulin-like growth factor binding protein 3 (IGFBP3) was most highly up-regulated. To link the NHLF results with in vivo disease, we analyzed lung tissue and bronchoalveolar lavage fluid from bleomycin-treated mice and found dramatically higher levels of FN and the FN-binding proteins IGFBP3, tenascin-C, and type I collagen in fibrotic conditions compared to controls. Altogether, our data identify a set of FN-binding proteins whose upregulation is characteristic of IPF and suggest that FN provides the foundational matrix for deposition of these proteins as fibrosis develops.

Restoring mechanophenotype reverts malignant properties of ECM-enriched vocal fold cancer

Increased extracellular matrix (ECM) and matrix stiffness promote solid tumor progression. However, mechanotransduction in cancers arising in mechanically active tissues remains underexplored. Here, we report upregulation of multiple ECM components accompanied by tissue stiffening in vocal fold cancer (VFC). We compare non-cancerous (NC) and patient-derived VFC cells - from early (mobile, T1) to advanced-stage (immobile, T3) cancers - revealing an association between VFC progression and cell-surface receptor heterogeneity, reduced laminin-binding integrin cell-cell junction localization and a flocking mode of collective cell motility. Mimicking physiological movement of healthy vocal fold tissue (stretching/vibration), decreases oncogenic nuclear β-catenin and YAP levels in VFC. Multiplex immunohistochemistry of VFC tumors uncovered a correlation between ECM content, nuclear YAP and patient survival, concordant with VFC sensitivity to YAP-TEAD inhibitors in vitro. Our findings present evidence that VFC is a mechanically sensitive malignancy and restoration of tumor mechanophenotype or YAP/TAZ targeting, represents a tractable anti-oncogenic therapeutic avenue for VFC.

The extracellular matrix component perlecan/HSPG2 regulates radioresistance in prostate cancer cells

Radiotherapy of prostate cancer (PC) can lead to the acquisition of radioresistance through molecular mechanisms that involve, in part, cell adhesion-mediated signaling. To define these mechanisms, we employed a DU145 PC model to conduct a comparative mass spectrometry-based proteomic analysis of the purified integrin nexus, i.e., the cell-matrix junction where integrins bridge assembled extracellular matrix (matrisome components) to adhesion signaling complexes (adhesome components). When parental and radioresistant cells were compared, the expression of integrins was not changed, but cell radioresistance was associated with extensive matrix remodeling and changes in the complement of adhesion signaling proteins. Out of 72 proteins differentially expressed in the parental and radioresistant cells, four proteins were selected for functional validation based on their correlation with biochemical recurrence-free survival. Perlecan/heparan sulfate proteoglycan 2 (HSPG2) and lysyl-like oxidase-like 2 (LOXL2) were upregulated, while sushi repeat-containing protein X-linked (SRPX) and laminin subunit beta 3 (LAMB3) were downregulated in radioresistant DU145 cells. Knockdown of perlecan/HSPG2 sensitized radioresistant DU145 RR cells to irradiation while the sensitivity of DU145 parental cells did not change, indicating a potential role for perlecan/HSPG2 and its associated proteins in suppressing tumor radioresistance. Validation in androgen-sensitive parental and radioresistant LNCaP cells further supported perlecan/HSPG2 as a regulator of cell radiosensitivity. These findings extend our understanding of the interplay between extracellular matrix remodeling and PC radioresistance and signpost perlecan/HSPG2 as a potential therapeutic target and biomarker for PC.

Wnt pathway inhibition with the porcupine inhibitor LGK974 decreases trabecular bone but not fibrosis in a murine model with fibrotic bone

G protein-coupled receptors (GPCRs) mediate a wide spectrum of physiological functions, including the development, remodeling, and repair of the skeleton. Fibrous dysplasia (FD) of the bone is characterized by fibrotic, expansile bone lesions caused by activating mutations in GNAS. There are no effective therapies for FD. We previously showed that ColI(2.3)+/Rs1+ mice, in which Gs-GPCR signaling was hyper-activated in osteoblastic cell lineages using an engineered receptor strategy, developed a fibrotic bone phenotype with trabecularization that could be reversed by normalizing Gs-GPCR signaling, suggesting that targeting the Gs-GPCR or components of the downstream signaling pathway could serve as a promising therapeutic strategy for FD. The Wnt signaling pathway has been implicated in the pathogenesis of FD-like bone, but the specific Wnts and which cells produce them remain largely unknown. Single-cell RNA sequencing on long-bone stromal cells of 9-wk-old male ColI(2.3)+/Rs1+ mice and littermate controls showed that fibroblastic stromal cells in ColI(2.3)+/Rs1+ mice were expanded. Multiple Wnt ligands were up- or downregulated in different cellular populations, including in non-osteoblastic cells. Treatment with the porcupine inhibitor LGK974, which blocks Wnt signaling broadly, induced partial resorption of the trabecular bone in the femurs of ColI(2.3)+/Rs1+ mice, but no significant changes in the craniofacial skeleton. Bone fibrosis remained evident after treatment. Notably, LGK974 caused significant bone loss in control mice. These results provide new insights into the role of Wnt and Gs-signaling in fibrosis and bone formation in a mouse model of Gs-GPCR pathway overactivation.