Matrix Remodeling Research Articles

SFRP2 modulates functional phenotype transition and energy metabolism of macrophages during diabetic wound healing.

Diabetic foot ulcer (DFU) is a serious complication of diabetes mellitus, which causes great health damage and economic burden to patients. The pathogenesis of DFU is not fully understood. We screened wound healing-related genes using bioinformatics analysis, and full-thickness skin injury mice model and cellular assays were used to explore the role of target genes in diabetic wound healing. SFRP2 was identified as a wound healing-related gene, and the expression of SFRP2 is associated with immune cell infiltration in DFU. In vivo study showed that suppression of SFRP2 delayed the wound healing process of diabetic mice, impeded angiogenesis and matrix remodeling, but did not affect wound healing process of control mice. In addition, suppression of SFRP2 increased macrophage infiltration and impeded the transition of macrophages functional phenotypes during diabetic wound healing, and affected the transcriptome signatures-related to inflammatory response and energy metabolism at the early stage of wound healing. Extracellular flux analysis (EFA) showed that suppression of SFRP2 decreased mitochondrial energy metabolism and increased glycolysis in injury-related macrophages, but impeded both glycolysis and mitochondrial energy metabolism in inflammatory macrophages. In addition, suppression of SFRP2 inhibited wnt signaling-related genes in macrophages. Treatment of AAV-SFRP2 augmented wound healing in diabetic mice and demonstrated the therapeutic potential of SFRP2. In conclusions, SFRP2 may function as a wound healing-related gene in DFU by modulating functional phenotype transition of macrophages and the balance between mitochondrial energy metabolism and glycolysis.

Crosstalk between macrophages and mesenchymal stem cells shape patterns of osteogenesis and immunomodulation in mineralized collagen scaffolds

Mesenchymal stem cells (MSCs) are highly plastic, with the capacity to differentiate into a spectrum of tissue-specific stromal cells. In the field of bone regeneration, MSCs have largely been considered for their osteogenic differentiation capacity. MSCs are increasingly being appreciated for their immunomodulatory potential following exposure to pro-inflammatory stimuli (licensing). Pro-inflammatory environments arise following bone injury via activation of resident immune cells like macrophages. We describe the use of a mineralized collagen scaffold as a bone-mimetic in vitro model to study the influence of paracrine versus direct cell-to-cell contact of THP-1 macrophages on MSC osteogenic and immunomodulatory potential. Paracrine stimuli from macrophages enhance MSC osteogenic and immunomodulatory potential via upregulation of key transcriptomic markers as well as via soluble biomolecule production. Direct co-culture of MSCs and macrophages decreased immunomodulatory potential in MSCs, especially for licensed MSCs, but enhanced matrix remodeling and expression of genes related to macrophage chemotaxis. These data demonstrate the significant effect macrophage-derived paracrine factors and direct contact have on MSC activity in a biomaterial model of bone regeneration. This work illuminates a critical need to further understand these processes in more clinically relevant cell models to inform biomaterial design.

On the pathogenesis of COVID-19: the role of transforming growth factor beta

Proteins of the transforming growth factor beta (TGF-β) family regulate numerous cellular processes that are essential in the pathogenesis of acute respiratory distress syndrome (ARDS), contributing to increased alveolar epithelial permeability, activation of fibroblasts, and extracellular matrix remodeling. TGF-β is involved in the pathogenesis of inflammatory respiratory diseases during the development of COVID-19. SARS-CoV-2 leads to complex immune responses that include the release of inflammatory cytokines, increased activity of mast cells, and the release of mast cell secretome, in particular profibrotic enzymes and cytokines, including TGF-β.Tryptaseand chymase-positive mast cells play a major role in pulmonary fibrosis and embolism in COVID-19. Mast cell chymase is angiotensin-converting enzyme 2-independent due to extracellular formation of angiotensin II in the interstitium; it also activates TGF-β and other molecules, thereby playing a role in tissue remodeling. Mast cell β-tryptase increases the secretion of TGF-β1 by airway smooth muscle tissue and the expression of α-smooth muscle actin (α-SMA). TGF-β also induces the generation of mitochondrial reactive oxygen species (ROS), which enhances the production of ROS in lung fibroblasts. TGF-β is crucial for induing the synthesis of extracellular matrix components by fibroblasts.The review is devoted to the structure of TGF-β, the sources of its secretion and functions, the mechanism of its involvement in the pathogenesis of COVID-19, and the possibility of its use as a prognostic marker of COVID-19 severity.

Microvascular Engineering for the Development of a Nonembedded Liver Sinusoid with a Lumen: When Endothelial Cells Do Not Lose Their Edge.

Microvascular engineering seeks to exploit known cell-cell and cell-matrix interactions in the context of vasculogenesis to restore homeostasis or disease development of reliable capillary models in vitro. However, current systems generally focus on recapitulating microvessels embedded in thick gels of extracellular matrix, overlooking the significance of discontinuous capillaries, which play a vital role in tissue-blood exchanges particularly in organs like the liver. In this work, we introduce a novel method to stimulate the spontaneous organization of endothelial cells into nonembedded microvessels. By creating an anisotropic micropattern at the edge of a development-like matrix dome using Marangoni flow, we achieved a long, nonrandom orientation of endothelial cells, laying a premise for stable lumenized microvessels. Our findings revealed a distinctive morphogenetic process leading to mature lumenized capillaries, demonstrated with both murine and human immortalized liver sinusoidal endothelial cell lines (LSECs). The progression of cell migration, proliferation, and polarization was clearly guided by the pattern, initiating the formation of a multicellular cord that caused a deformation spanning extensive regions and generated a wave-like folding of the gel, hinged at a laminin-depleted zone, enveloping the cord with gel proteins. This event marked the onset of lumenogenesis, regulated by the gradual apico-basal polarization of the wrapped cells, leading to the maturation of vessel tight junctions, matrix remodeling, and ultimately the formation of a lumen─recapitulating the development of vessels in vivo. Furthermore, we demonstrate that the process strongly relies on the initial gel edge topography, while the geometry of the vessels can be tuned from a curved to a straight structure. We believe that our facile engineering method, guiding an autonomous self-organization of vessels without the need for supporting cells or complex prefabricated scaffolds, holds promise for future integration into microphysiological systems featuring discontinuous, fenestrated capillaries.

Identification and Verification of Potential Markers Related to Myocardial Fibrosis by Bioinformatics Analysis.

Mounting evidence indicates that myocardial fibrosis (MF) is frequently intertwined with immune and metabolic disorders. This comprehensive review aims to delve deeply into the crucial role of immune-related signature genes in the pathogenesis and progression of MF. This exploration holds significant importance as understanding the underlying mechanisms of MF is essential for developing effective diagnostic and therapeutic strategies. The dataset GSE9735 about myocardial fibrosis and non-fibrosis was downloaded from GEO database. Differentially expressed genes (DEGs) were identified by 'limma' package in R software. Then, the biological function of DEG was determined by gene ontology (GO) and Kyoto Encyclopedia of Genes and Genomes (KEGG) pathway enrichment analysis. XCell was used to estimate the composition pattern of matrix and immune cells. Protein-protein interaction (PPI) network was constructed based on STRING analysis software, and Hub genes were screened and functional modules were analyzed. The correlation between hub genes and immune cell subtypes was analyzed. Hub genes with |correlation coefficient|> 0.45 and p-value < 0.05 were used as characteristic biomarkers. Finally, the logistic regression model is used to verify the three markers in the training set and verification set (GSE97358 and GSE225336). A total of 635 DEGs were identified. Functional enrichment analysis shows that inflammation and immune response, extracellular matrix and structural remodeling play an important role in the pathological mechanism of MF. Immune cell infiltration analysis showed that immune cells (Plasma cells, Eosinophils, Chondrocytes and Th2 cells) significantly changed in MF pathological conditions. In PPI network analysis, IL1β, TTN, PTPRC, IGF1, ALDH1A1, CYP26A1, ALDH1A3, MYH11, CSF1R and CD80 were identified as hub genes, among which IL1β, CYP26A1 and GNG2 were regarded as immune-related characteristic markers. The AUC scores of the three biomarkers are all above 0.65, which proves that they have a good discrimination effect in MF. In this study, three immune-related genes were identified as diagnostic biomarkers of MF, which provided a new perspective for exploring the molecular mechanism of MF. This study takes a comprehensive approach to understanding the intricate relationship between myocardial fibrosis and immune metabolism. By identifying key immune-related biomarkers, this study not only reveals the molecular basis of myocardial fibrosis but also paves the way for the development of novel diagnostic tools and therapeutic strategies. These findings are critical for improving patient prognosis and may have broader implications for studying and treating other cardiovascular diseases associated with immune dysregulation.

Low-intensity pulsed ultrasound improves metabolic dysregulation in obese mice by suppressing inflammation and extracellular matrix remodeling

Chronic inflammation in white adipose tissue is crucial in obesity and related metabolic disorders. Low-intensity pulsed ultrasound (LIPUS) is renowned for its anti-inflammatory effects as a non-invasive treatment, yet its precise role in obesity has been uncertain. Our study investigates the therapeutic effect of LIPUS and its underlying mechanism on obesity in mice, thereby offering a novel approach for non-invasive treatment of obesity and associated metabolic disorders for human. Male C57BL/6J mice aged 10 weeks were fed a high-fat diet (HFD) for 8 weeks to establish obesity model, then underwent 8 weeks of LIPUS (frequency: 1.0 MHz, duty cycle: 20 %, Isata: 58–61 mW/cm2, 20 min per day) stimulation of the epididymal white adipose tissue. Fat and lean mass were measured using nuclear magnetic resonance (NMR), while energy homeostasis was evaluated using metabolic cages. Insulin resistance was assessed using glucose tolerance tests (GTT) and insulin tolerance tests (ITT). Regulatory mechanisms were explored using RNA sequencing. Results showed that LIPUS significantly reduced obesity markers in obese mice, including body and adipose tissue weight, and improved insulin resistance, without affecting food intake. RNA sequencing showed 250 up-regulated and 351 down-regulated genes between HFD-LIPUS group and HFD-Sham group, suggesting anti-inflammatory action. Quantitative PCR confirmed reduced pro-inflammatory gene expression and macrophage infiltration in eWAT. Gene set enrichment analysis showed decreased NF-κB signaling and extracellular matrix-receptor interactions in LIPUS-treated mice. Thus, LIPUS effectively mitigates metabolic dysregulation in HFD-induced obesity through inflammation suppression and extracellular matrix remodeling, which provides a potential physical therapy for metabolic syndrome in clinic.

Collaborative Enhancement of Diabetic Wound Healing and Skin Regeneration by Recombinant Human Collagen Hydrogel and hADSCs.

Stem cell-based therapies hold significant promise for chronic wound healing and skin appendages regeneration, but challenges such as limited stem cell lifespan and poor biocompatibility of delivery systems hinder clinical application. In this study, an in situ delivery system for human adipose-derived stem cells is developed (hADSCs) to enhance diabetic wound healing. The system utilizes a photo-crosslinking recombinant human type III collagen (rHCIII) hydrogel to encapsulate hADSCs, termed the hADSCs@rHCIII hydrogel. This hydrogel undergoes local crosslinking at the wound site, establishing a sturdy 3D niche suitable for stem cell function. Consequently, the encapsulated hADSCs exhibit strong attachment and spreading within the hydrogels, maintaining their proliferation, metabolic activity, and viability for up to three weeks in vitro. Importantly, in vivo studies demonstrate that the hADSCs@rHCIII hydrogel achieves significant in situ delivery of stem cells, prolonging their retention within the wound. This ultimately enhances their immunomodulatory capabilities, promotes neovascularization and granulation tissue formation, facilitates matrix remodeling, and accelerates healing in a diabetic mouse wound model. Collectively, these findings highlight the potential of the conveniently-prepared and user-friendly hADSCs@rHCIII hydrogel as a promising therapeutic approach for diabetic wound treatment and in situ skin regeneration.

Biomechanical changes occur in myopic choroidal stroma and mirror those in the adjacent sclera

Retina-derived growth signals relayed from the choroid to the sclera cause remodeling of the extracellular scleral matrix, resulting in myopic ocular elongation. However, to the best of our knowledge, no studies have assessed changes in choroidal stromal biomechanical properties during myopia progression. Here we utilized 7 µm-resolution scanning acoustic microscopy (SAM) to assess biomechanical properties (bulk modulus (K) and mass density (rho)) of choroidal stroma from guinea pig eyes with form-deprivation (FD) induced myopia. The choroidal stroma had considerable intrinsic strength arising from its biomechanical properties and these were differentially affected by myopia in central and peripheral regions. Choroidal stromal biomechanical values were also highly correlated with those in adjacent scleral regions, and the choroidal stromal-scleral association was stronger in myopic eyes. Biomechanical changes observed in the choroidal stroma of myopic eyes were mirrored to those observed in the adjacent sclera. These findings suggest that choroidal stromal remodeling may accompany myopia and open the door to the source of the signals that cause scleral remodeling in myopia.

OSCC-derived EVs educate fibroblasts and remodel collagen landscape

Cancer-associated myofibroblasts (mCAFs) represent a significant component of the tumor microenvironment due to their contributions to extracellular matrix (ECM) remodeling. The pro-tumor mechanisms of extracellular vesicles (EVs) by regulating mCAFs and related collagens remain poorly understood in oral squamous cell carcinoma (OSCC). In this study, through analysis of single-cell sequencing data and immunofluorescence staining, we confirmed the increased presence of mCAFs and enrichment of specific collagen types in OSCC tissues. Furthermore, we demonstrated that OSCC-derived EVs promote the transformation of fibroblasts into mCAFs, leading to tumor invasion. Proteomic analysis identified the presence of TGF-β1 in EVs and revealed its role in inducing mCAFs via the TGF-β1/Smad3 signaling pathway. Experiments in vivo confirmed that EVs, particularly those carrying TGF-β1, trigger COL18high COL5high matrix deposition, thereby forming the pro-tumor ECM in OSCC. In summary, our investigation unveils the significant involvement of OSCC-derived EVs in orchestrating the differentiation of fibroblasts into mCAFs and modulating specific collagen types within the ECM. Therefore, this study provides a theoretical basis for targeting the EV-mediated TGF-β1 signaling pathway as a potential therapeutic strategy for OSCC.

Epigenetic landscape reorganisation and reactivation of embryonic development genes are associated with malignancy in IDH-mutant astrocytoma

Accurate grading of IDH-mutant gliomas defines patient prognosis and guides the treatment path. Histological grading is challenging, and aside from CDKN2A/B homozygous deletions in IDH-mutant astrocytomas, there are no other objective molecular markers used for grading. RNA-sequencing was conducted on primary IDH-mutant astrocytomas (n = 138) included in the prospective CATNON trial, which was performed to assess the prognostic effect of adjuvant and concurrent temozolomide. We integrated the RNA-sequencing data with matched DNA-methylation and NGS data. We also used multi-omics data from IDH-mutant astrocytomas included in the TCGA dataset and validated results on matched primary and recurrent samples from the GLASS-NL study. Since discrete classes do not adequately capture grading of these tumours, we utilised DNA-methylation profiles to generate a Continuous Grading Coefficient (CGC) based on classification scores from a CNS-tumour classifier. CGC was an independent predictor of survival outperforming current WHO-CNS5 and methylation-based classification. Our RNA-sequencing analysis revealed four distinct transcription clusters that were associated with (i) upregulation of cell cycling genes; (ii) downregulation of glial differentiation genes; (iii) upregulation of embryonic development genes (e.g. HOX, PAX, and TBX) and (iv) upregulation of extracellular matrix genes. The upregulation of embryonic development genes was associated with a specific increase of CpG island methylation near these genes. Higher grade IDH-mutant astrocytomas have DNA-methylation signatures that, on the RNA level, are associated with increased cell cycling, tumour cell de-differentiation and extracellular matrix remodelling. These combined molecular signatures can serve as an objective marker for grading of IDH-mutant astrocytomas.

Human Umbilical Cord-Mesenchymal Stem Cells Promote Extracellular Matrix Remodeling in Microglia.

Human mesenchymal stem cells modulate the immune response and are good candidates for cell therapy in neuroinflammatory brain disorders affecting both adult and premature infants. Recent evidence indicates that through their secretome, mesenchymal stem cells direct microglia, brain-resident immune cells, toward pro-regenerative functions, but the mechanisms underlying microglial phenotypic transition are still under investigation. Using an in vitro coculture approach combined with transcriptomic analysis, we identified the extracellular matrix as the most relevant pathway altered by the human mesenchymal stem cell secretome in the response of microglia to inflammatory cytokines. We confirmed extracellular matrix remodeling in microglia exposed to the mesenchymal stem cell secretome via immunofluorescence analysis of the matrix component fibronectin and the extracellular crosslinking enzyme transglutaminase-2. Furthermore, an analysis of hallmark microglial functions revealed that changes in the extracellular matrix enhance ruffle formation by microglia and cell motility. These findings point to extracellular matrix changes, associated plasma membrane remodeling, and enhanced microglial migration as novel mechanisms by which mesenchymal stem cells contribute to the pro-regenerative microglial transition.

Mechanical Stress-Oxidative Stress Axis: Biological Basis in the Vaginal Wall and Pelvic Floor Muscles of Rats with Simulated Birth Injury.

Vaginal delivery and resulting pelvic floor muscle (PFM) dysfunction are significant risk factors for pelvic floor dysfunction (PFD). Despite this, the biological basis underlying PFD after childbirth remain unclear. This study was aimed at assessing the early response of the vaginal wall and PFM to simulated birth injury (SBI) in rats. Forty female Sprague-Dawley rats were divided into four groups: control (sham operation), and 1, 4, and 14days post-injury. In the SBI groups, a catheter was inserted into the vagina with 130g of weight attached to the end, and the balloon was inflated to 5ml for 2h. Evaluation of vaginal tissues and PFMs included histological, immunohistochemical, Western blot, and uniaxial biomechanical testing. In the vaginal wall, the SBI group showed significantly lower COL1A1 expression and higher MMP-2 and MMP-9 expression. At 4 and 14days post-injury, there was a significant decrease in PFM fiber area and increased collagen content. The SBI group also exhibited significant increases in the expression of Nrf2, NQO1, HO-1, and SOD-2, indicating involvement of oxidative stress in both the vaginal wall and PFMs. Protein expression of Pax7 and MyoG, as well as the number of fibers with centralized nuclei, continued to increase significantly after SBI. Additionally, the vaginal wall of the SBI group showed a decreasing trend in tensile strength and elastic modulus, with a greater ultimate strain. Extracellular matrix remodeling, oxidative stress, decreased biomechanical properties, and muscle dysmyogenesis may collectively contribute to increased susceptibility to PFD development.

Topical Platelet Exosomes Reduce Senescence Signaling in Human Skin: An Exploratory Prospective Trial.

Cellular senescence, an irreversible cell cycle arrest with secretory phenotype, is a hallmark of skin aging. Regenerative exosome-based approaches, such as topical human platelet extract (HPE), are emerging to target age-related skin dysfunction. To evaluate the cellular and molecular effects of topical HPE for skin rejuvenation after 12 weeks of twice daily use. Skin biopsies were obtained for histological evaluation of senescence markers, p16INK4a and p21CIP1/WAF1. Telomere-associated foci, coassociation of telomeres, and DNA damage marker, γH2AX, were assessed. RNA sequencing evaluated senescence associated secretory phenotype (SASP) and extracellular matrix pathways. p16INK4a and p21CIP1/WAF1 staining in senescent skin cells revealed low and high expression subgroups that did not correspond to chronological age. Topical HPE significantly reduced high p16INK4a cells in the dermis (p = .02). There was also a decrease in telomere damage after topical HPE (p = .03). In patients with high senescent cells at baseline, there was a 40% reduction in proinflammatory SASP. Extracellular matrix remodeling pathways, including collagen and elastic fibers, were up-regulated. Topical HPE, applied on intact skin, reduced senescence signaling and senescence-associated telomere damage after 12 weeks of twice daily use, targeting a path for skin longevity or healthy skin aging.

LRP1 Repression by SNAIL Results in ECM Remodeling in Genetic Risk for Vascular Diseases.

Genome-wide association studies implicate common genetic variations in the LRP1 (low-density lipoprotein receptor-related protein 1) locus at risk for multiple vascular diseases and traits. However, the underlying biological mechanisms are unknown. Fine mapping analyses included Bayesian colocalization to identify the most likely causal variant. Human induced pluripotent stem cells were genome-edited using CRISPR-Cas9 to delete or modify candidate enhancer regions and generate LRP1 knockout cell lines. Cells were differentiated into smooth muscle cells through a mesodermal lineage. Transcription regulation was assessed using luciferase reporter assay, transcription factor knockdown, and chromatin immunoprecipitation. Phenotype changes in cells were conducted using cellular assays, bulk RNA sequencing, and mass spectrometry. Multitrait colocalization analyses pointed at rs11172113 as the most likely causal variant in LRP1 for fibromuscular dysplasia, migraine, pulse pressure, and pulmonary function trait. We found the rs11172113-T allele to associate with higher LRP1 expression. Genomic deletion in induced pluripotent stem cell-derived smooth muscle cells supported rs11172113 to locate in an enhancer region regulating LRP1 expression. We found transcription factors MECP2 (methyl CpG binding protein 2) and SNAIL to repress LRP1 expression through an allele-specific mechanism, involving SNAIL interaction with disease risk allele. LRP1 knockout decreased induced pluripotent stem cell-derived smooth muscle cell proliferation and migration. Differentially expressed genes were enriched for collagen-containing extracellular matrix, connective tissue development, and lung development. LRP1 knockout and deletion of rs11172113 enhancer showed potentiated canonical TGF-β (transforming growth factor beta) signaling through enhanced phosphorylation of SMAD2/3. Analyses of the protein content of decellularized extracts indicated partial extracellular matrix remodeling involving enhanced secretion of CYR61, a known LRP1 ligand involved in vascular integrity and TIMP3, implicated in extracellular matrix maintenance and also known to interact with LRP1. Our findings support allele-specific LRP1 gene repression by the endothelial-to-mesenchymal transition regulator SNAIL. We propose decreased LRP1 expression in smooth muscle cells to remodel the extracellular matrix enhanced by TGF-β as a potential mechanism of this pleiotropic locus for vascular diseases.

Identification of SLC22A17 DNA methylation hotspot as a potential biomarker in cutaneous melanoma

BackgroundCancer onset and progression are driven by genetic and epigenetic alterations leading to oncogene activation and the silencing of tumor suppressor genes. Among epigenetic mechanisms, DNA methylation (methDNA) is gaining growing interest in cancer. Promoter hypomethylation is associated with oncogene activation while intragenic methDNA can be involved in transcriptional elongation, alternative spicing, and the activation of cryptic start sites. Several genes involved in the modulation of the tumor microenvironment are regulated by methDNA, including the Solute Carrier Family 22 Member 17 (SLC22A17), which is involved in iron trafficking and extracellular matrix remodeling cooperating with the Gelatinase-Associated Lipocalin (NGAL) ligand. However, the exact role of intragenic methDNA in cancer has not been fully investigated. Therefore, the aim of the present study is to explore the role of methDNA in the regulation of SLC22A17 in cutaneous melanoma (CM), used as a tumor model.MethodsCorrelation and differential analyses between SLC22A17 expression and methDNA were performed using the data contained in The Cancer Genome Atlas and Gene Expression Omnibus databases. Functional studies on melanoma cell lines treated with 5-Azacytidine (5-Aza) were conducted to assess the correlation between methDNA and SLC22A17 expression. A validation study on the diagnostic potential of the in silico-identified SLC22A17 methDNA hotspot was finally performed by analyzing tissue samples obtained from CM patients and healthy controls.ResultsThe computational analyses revealed that SLC22A17 was significantly downregulated in CM, and its expression was related to promoter hypomethylation and intragenic hypermethylation. Moreover, SLC22A17 overexpression and hypermethylation of two intragenic methDNA hotspots were associated with a better clinical outcome in CM patients. The correlation between SLC22A17 methDNA and expression was confirmed in 5-Aza-treated cells. In agreement with in silico analyses, the SLC22A17 promoter methylation hotspot showed higher methDNA levels in CM samples compared to nevi. In addition, the methDNA levels of this hotspot were positively correlated with advanced CM.ConclusionsThe SLC22A17 methDNA hotspot could represent a promising biomarker for CM, highlighting the regulatory role of methDNA on SLC22A17 expression. These results pave the way for the identification of novel epigenetic biomarkers and therapeutic targets for the management of CM patients.

Cellular taxonomy of the preleukemic bone marrow niche of acute myeloid leukemia.

Leukemias arise from recurrent clonal mutations in hematopoietic stem/progenitor cells (HSPCs) that cause profound changes in the bone marrow microenvironment (BMM) favoring leukemic stem cell (LSC) growth over normal HSPCs. Understanding the cross talk between preleukemic mutated HSPCs and the BMM is critical to develop novel therapeutic strategies to prevent leukemogenesis. We hypothesize that preleukemic-LSCs (pLSCs) induce BMM changes critical for leukemogenesis. Using our AML-murine model, we performed single-cell RNA-sequencing of preleukemic BMM (pBMM) cells. We found normal HSC (nHSC)-regulating LepR+ mesenchymal stem cells, and endothelial cells were decreased, along with increases in CD55+ fibroblasts and pericytes. Preleukemic CD55+ fibroblasts had higher proliferation rates and decreased collagen expression, suggesting extracellular matrix remodeling during leukemogenesis. Importantly, co-culture assays found preleukemic CD55+ fibroblasts expanded pLSCs significantly over nHSCs. In conclusion, we have identified a distinct pBMM and a novel CD55+ fibroblast population that is expanded in pBMM that promote fitness of pLSCs over nHSCs.

Age- and sex-specific biomechanics and extracellular matrix remodeling of the ascending aorta in a mouse model of severe Marfan syndrome.

Thoracic aortic aneurysm (TAA) is associated with Marfan syndrome (MFS), a connective tissue disorder caused by mutations in fibrillin-1. Sexual dimorphism has been recorded for TAA outcomes in MFS, but detailed studies on the differences in TAA progression in males and females and their relationships to outcomes have not been performed. The aims of this study were to determine sex differences in the diameter dilatation, mechanical properties, and extracellular matrix (ECM) remodeling over time in a severe mouse model (Fbn1mgR/mgR = MU) of MFS-associated TAA that has a shortened life span. Male and female MU and wildtype (WT) mice were used at 1-4 mo of age. Blood pressure and in vivo diameters of the ascending thoracic aorta were recorded using a tail-cuff system and ultrasound imaging, respectively. Ex vivo mechanics and ECM remodeling of the aorta were characterized using a biaxial test system and multiphoton imaging, respectively. We showed that mechanical properties, such as structural and material stiffness, and ECM remodeling, such as elastic and collagen fiber content, correlated with diameter dilatation during TAA progression. Male MU mice had accelerated rates of diameter dilatation, stiffening, and ECM remodeling compared with female MU mice which may have contributed to their decreased life span. The correlation of mechanical properties and ECM remodeling with diameter dilatation suggests that they may be useful biomarkers for TAA progression. The differences in diameter dilatation and life spans in male and female MU mice indicate that sex is an important consideration for managing thoracic aortic aneurysm in MFS. NEW & NOTEWORTHY Using a mouse model (Fbn1mgR/mgR = MU) of severe thoracic aortic aneurysm in Marfan syndrome (MFS), we found that male MU aorta had an accelerated time line and increased amounts of dilatation, stiffening, and extracellular matrix (ECM) remodeling compared with female MU aorta that may have contributed to an increased risk of fatigue failure with cyclic loading over time and a reduced life span. We suggest that aortic stiffness may provide useful information for clinical management of aneurysms in MFS.

Pharmacological antagonism of Ccr2+ cell recruitment to facilitate regenerative tendon healing.

Successful tendon healing requires sufficient deposition and remodeling of new extracellular matrix at the site of injury, with this process mediating in part through fibroblast activation via communication with macrophages. Moreover, resolution of healing requires clearance or reversion of activated cells, with chronic interactions with persistent macrophages impairing resolution and facilitating the conversion to fibrotic healing. As such, modulation of the macrophage environment represents an important translational target to improve the tendon healing process. Circulating monocytes are recruited to sites of tissue injury, including the tendon, via upregulation of cytokines including Ccl2, which facilitates recruitment of Ccr2+ macrophages to the healing tendon. Our prior work has demonstrated that Ccr2-/- can modulate fibroblast activation and myofibroblast differentiation. However, this approach lacked temporal control and resulted in healing impairments. Thus, in the current study we have leveraged a Ccr2 antagonist to blunt macrophage recruitment to the healing tendon in a time-dependent manner. We first tested the effects of Ccr2 antagonism during the acute inflammatory phase and found that this had no effect on the healing process. In contrast, Ccr2 antagonism during the early proliferative/granulation tissue period resulted in significant improvements in mechanical properties of the healing tendon. Collectively, these data demonstrate the temporally distinct impacts of modulating Ccr2+ cell recruitment and Ccr2 antagonism during tendon healing and highlight the translational potential of transient Ccr2 antagonism to improve the tendon healing process.

Clinical Efficacy and Safety of Low-Energy Extracorporeal Shock Wave Therapy for Various Conditions of Deep Dermal and Subdermal Fibrosis.

Extracorporeal shock wave therapy (ESWT) enhances extracellular matrix remodeling and tissue regeneration by promoting growth factor release, regulating blood and lymphatic flows, and reducing fat and fibrotic tissues. Focused shock wave therapy (F-SWT), radial shock wave therapy (R-SWT), and combined F-SWT and R-SWT have been used to deliver different patterns of shock energy depending on the characteristics of the target lesions. We investigated the efficacy and safety of ESWT in patients with dermal and subdermal fibrosis. Fifty-two patients treated with F-SWT and/or R-SWT for dermal and subdermal fibrosis caused due to various reasons were retrospectively analyzed by reviewing their medical records, clinical images, and ultrasound study images. The mean number of pulses administered for F-SWT on the cheek, temple, and chin were 2600.0 ± 1040.8 shocks/session and for R-SWT were 5080.0 ± 2234.6 pulses/session, and the number of treatment sessions were 8.0 ± 4.4. In patients who were treated with ESWT on the abdomen, the mean number of pulses for F-SWT were 2600.0 ± 2408.3 shocks/session and for R-SWT were 8400.0 ± 894.4 pulses/session, and the number of treatment sessions were 3.2 ± 1.6. Most patients were satisfied with the results. Pain during ESWT was well tolerated and post-ESWT edema was more common in R-SWT than in F-SWT. Our data demonstrated that ESWT effectively and safely improved the clinical appearance and functional movement of patients with dermal and subdermal fibrosis caused due to various reasons.

Enhancing uterine receptivity for embryo implantation through controlled collagenase intervention.

Ineffective endometrial matrix remodeling, a key factor in infertility, impedes embryo implantation in the uterine wall. Our study reveals the cellular and molecular impact of human collagenase-1 administration in mouse uteri, demonstrating enhanced embryo implantation rates. Collagenase-1 promotes remodeling of the endometrial ECM, degrading collagen fibers and proteoglycans. This process releases matrix-bound bioactive factors (e.g., VEGF, decorin), facilitating vascular permeability and angiogenesis. Collagenase-1 elevates embryo implantation regulators, including NK cell infiltration and the key cytokine LIF. Remarkably, uterine tissue maintains structural integrity despite reduced endometrial collagen fiber tension. In-utero collagenase-1 application rescues implantation in heat stress and embryo transfer models, known for low implantation rates. Importantly, ex vivo exposure of human uterine tissue to collagenase-1 induces collagen de-tensioning and VEGF release, mirroring remodeling observed in mice. Our research highlights the potential of collagenases to induce and orchestrate cellular and molecular processes enhancing uterine receptivity for effective embryo implantation. This innovative approach underscores ECM remodeling mechanisms critical for embryo implantation.