Myofibroblasts and mechano-regulation of connective tissue remodelling

Successful treatment of a keloid on the upper lip by trepanation and radiotherapy: a case report

Purpose: Keloid tissue represents an abnormal proliferation of fibroblasts, typically resulting from skin injury. These lesions can lead to significant physiological dysfunction and aesthetic concerns, particularly when located on the face. Traditional treatments, such as intralesional injections, laser therapy, and surgical excision, have shown limited efficacy and are associated with high recurrence rates.

Materials and methods: In a recent case, a 19-year-old male with a keloid on the upper lip did not respond to local injections of triamcinolone acetonide (TAC) or carbon dioxide ablative fractional resurfacing laser therapy.

Results: A combined treatment approach involving trepanation and superficial radiotherapy successfully flattened the keloid tissue, with no recurrence observed during a 3-year follow-up period.

Conclusions: This case underscores the potential efficiency and safety of combined therapeutic interventions and contributes valuable evidence towards the development of novel treatment strategies for keloids.

Promotion of quiescence and maintenance of function of mesenchymal stem cells on substrates with surface potential

The widespread use of human mesenchymal stem cells(hMSCs) is impeded by functional loss during prolonged expansion. Although multiple approaches have been attempted to preserve hMSCs stemness, a suitable culture system remains to be modified. The interaction between electrical signals and stem cells is expected to better maintain the function of stem cells. However, it remains unclear whether the surface potential of substrates has the potential to preserve stem cell function during in vitro expansion. In our study, hMSCs cultured on materials with different surface potentials could be induced into a reversible quiescent state, and we demonstrated that quiescent hMSCs could be reactivated and transitioned back into the proliferation cell cycle. hMSCs cultured under appropriate potential displayed superior differentiation and proliferation abilities within the same generation compared to conventional conditions. These findings underscore the importance of surface potential as a critical physical factor regulating hMSCs stemness. Manipulating the surface potential of hMSCs culture substrates holds promise for optimising preservation and culture conditions, thereby enhancing their application in tissue repair and regeneration engineering.

Cluster Analysis of VERDICT MRI for Cancer Tissue Characterization in Neuroendocrine Tumors

Diffusion MRI models accounting for varying diffusion times and high b-values, such as VERDICT, hold potential for non-invasively characterizing tumor tissue types, potentially enabling improved tumor grading, and treatment evaluation. Furthermore, cluster analysis can aid in identifying multidimensional patterns in the diffusion MRI (dMRI) data that are not apparent when analyzing individual parameters in isolation. The aim of this study was to evaluate how well cluster analysis of VERDICT parameters can be used for intratumor tissue characterization compared to ADC in a mouse model of human small intestine neuroendocrine tumor (GOT1), and to validate the method by histological analysis. Mice implanted with GOT1 were irradiated and subsequently imaged using a dMRI protocol designed for estimation of VERDICT parameters and ADC values. Histological analysis using hematoxylin and eosin (H&E), Masson's trichrome, and Ki67 staining identified three distinct tumor tissue types: necrotic, fibrotic, and viable tumor tissue. ROIs were drawn on regions of high and low ADC, which spatially matched with necrosis or fibrosis, and viable tumor tissue, respectively. Among the VERDICT parameters, the cell radius index (R) was most effective in distinguishing between necrotic and fibrotic tissue, whereas the intracellular fraction (fIC) was the most effective in differentiating viable from non-viable tissue. A Gaussian mixture model (GMM) of three clusters, representing each tumor tissue type, was fitted to R and fIC of all tumor voxel data. VERDICT cluster maps corresponded well with the histology classification maps overall. Fibrotic tissue corresponded best with the cluster of low fIC and low R, necrotic tissue with the cluster of low fIC and high R, and viable tumor tissue with the cluster of high fIC and intermediate R. In conclusion, GMM cluster analysis of VERDICT MRI data shows potential in differentiating necrotic, fibrotic, and viable tumor tissue in irradiated GOT1 tumors.

Novel high throughput 3D ECM remodeling assay identifies MEK as key driver of fibrotic fibroblast activity

In fibrotic tissues, activated fibroblasts remodel the collagen-rich extracellular matrix (ECM). Intervening with this process represents a candidate therapeutic strategy to attenuate disease progression. Models that generate quantitative data on 3D fibroblast-mediated ECM remodeling with the reproducibility and throughput needed for drug testing are lacking. Here, we develop a model that fits this purpose and produces combined quantitative information on drug efficacy and cytotoxicity. We use microinjection robotics to design patterns of fibrillar collagen-embedded fibroblast clusters and apply automated microscopy and image analysis to quantify ECM remodeling between-, and cell viability within clusters of TGFβ-activated primary human skin or lung fibroblasts. We apply this assay to compound screening and reveal actionable targets to suppress fibrotic ECM remodeling. Strikingly, we find that after an initial phase of fibroblast activation by TGFβ, canonical TGFβ signaling is dispensable and, instead, non-canonical activation of MEK-ERK signaling drives ECM remodeling. Moreover, we reveal that higher concentrations of two TGFβ receptor inhibitors while blocking canonical TGFβ signaling, in fact stimulate this MEK-mediated profibrotic ECM remodeling activity.

Inhibition of Talin2 dedifferentiates myofibroblasts and reverses lung and kidney fibrosis

Fibrosis is involved in 45% of deaths in the United States, and no treatment exists to reverse progression of the disease. To find novel targets for fibrosis therapeutics, we developed a model for the differentiation of monocytes to myofibroblasts that allowed us to screen for proteins involved in myofibroblast differentiation. Inhibition of a novel protein target generated by our model, talin2, reduces myofibroblast-specific morphology, α-smooth muscle actin content, and collagen I content and lowers the pro-fibrotic secretome of myofibroblasts. We find that knockdown of talin2 de-differentiates myofibroblasts and reverses bleomycin-induced lung fibrosis in mice, and further that Tln2-/- mice are resistant to bleomycin-induced lung fibrosis and resistant to unilateral ureteral obstruction-induced kidney fibrosis. Talin2 inhibition is thus a potential treatment for reversing lung and kidney fibroses.

Mechanics Mediated Semi-Convertible Hydrogel Enabled Sustained Drug Release

The dynamic mechanic environment surrounding the wound may retard wound healing, and even lead to an exacerbation of inflammation and scar. How to actively promote wound healing under a dynamic mechanical environment during human motion is still a long-standing challenge. Therefore, a mechanics mediated semi-convertible hydrogel (MechSCH) loaded with drug is proposed in this study employing the synergistic interaction between mechanics mediated supramolecular non-covalent networks and polyvinyl alcohol/Gelatin polymer networks for enhancing dynamic wound healing. The formed MechSCH exhibits a partial gel-sol transition even under a shear stress of ≈9.04 Pa that is satisfied with most tissues or organs' stress. The sustained release of encapsulated drugs would be efficiently compared with the mechanics of non-sensitive polyvinyl alcohol/Gelatin hydrogel. The loaded platelet-derived growth factor (PDGF) of the MechSCH exhibited a rapid onset of therapeutic effect in a mice dorsal full-thickness dermal wound model, which demonstrated sustaining drug release through mechanics of skin tension at the wound site, along with alleviating the inflammation and promoting rapid vascular regeneration. This mechanics mediated semi-convertible hydrogel presents potential clinical applications for the dynamic management of chronic wounds.

The potential application of stroma modulation in targeting tumor cells: focus on pancreatic cancer and breast cancer models

The tumor microenvironment (TME) plays a crucial role in cancer development and spreading being considered as "the dark side of the tumor". Within this term tumor cells, immune components, supporting cells, extracellular matrix and a myriad of bioactive molecules that synergistically promote tumor development and therapeutic resistance, are included. Recent findings revealed the profound impacts of TME on cancer development, serving as physical support, critical mediator and biodynamic matrix in cancer evolution, immune modulation, and treatment outcomes. TME targeting strategies built on vasculature, immune checkpoints, and immuno-cell therapies, have paved the way for revolutionary clinical interventions. On this basis, the relevance of pre-clinical and clinical investigations has rapidly become fundamental for implementing novel therapeutical strategies breaking cell-cell and cell -mediators' interactions between TME components and tumor cells. This review summarizes the key players in the breast and pancreatic TME, elucidating the intricate interactions among cancer cells and their essential role for cancer progression and therapeutic resistance. Different tumors such breast and pancreatic cancer have both different and similar stroma features, that might affect therapeutic strategies. Therefore, this review aims to comprehensively evaluate recent findings for refining breast and pancreatic cancer therapies and improve patient prognoses by exploiting the TME's complexity in the next future.

Sinonasal angiofibroma in a horse

A 34-year-old Haflinger gelding presented with a unilateral, expansile, intranasal mass that regrew after partial excision. After euthanasia, a large pedunculated mass that originated from the left caudal maxillary sinus and obliterated the left nasal cavity was seen by radiological and macroscopic examination. Histopathology revealed a poorly cellular, expansile, well-vascularized neoplasm composed of a loosely arranged meshwork of spindle cells and collagen fibres. Spindle cells were immunopositive for alpha-smooth muscle actin and occasionally for vimentin, whereas endothelial cells immunolabelled for factor VIII-related antigen. Based on clinical, radiological, macroscopic and microscopic similarities to canine and human cases, the mass was diagnosed as an angiofibroma.

Efficacy of xenogeneic fresh and lyophilized amniotic membranes on the healing of experimentally induced full-thickness skin wounds in dogs

Wound healing is a complex process involving multiple phases aimed at repairing damaged tissues. Disruptions in this process can lead to chronic wounds and infections. Effective treatments that maintain cellular bioactivity while being cost-effective and easy to manufacture and store are needed. The amniotic membrane (AM) is highly biocompatible and rich in bioactive factors, making it valuable for regenerative medicine. Bovine AM is noteworthy for its large size, which facilitates its use in medical settings. However, preserving its bioactivity during storage is a challenge. Therefore, this study aimed to evaluate the effect of bovine lyophilized AM on full-thickness skin wound healing in dogs, compared to that of fresh AM. Bovine AM was collected, lyophilized, and characterized by quantifying growth factors, including vascular endothelial growth factor (VEGF) and basic fibroblast growth factor (bFGF), as well as collagen, glycosaminoglycans (GAGs), elastin, and DNA. Additionally, the surface morphology was imaged using scanning electron microscopy (SEM). The effects of conditioned media from fresh and lyophilized AM on fibroblast and endothelial cell proliferation were compared. In vivo, three full-thickness skin wounds were created on the back in twelve dogs and treated with saline (control), fresh AM, or lyophilized AM, and monitored for healing over 1, 3, and 5 weeks. The fresh AM contained 57.3 ± 6.21 µg/mg collagen, 5.62 ± 1.1 µg/mg GAGs, 11.6 ± 4.52 µg/mg elastin, and 46.3 ± 12.8 ng/mg DNA, with VEGF and bFGF levels of 5.43 ± 2.485 and 1.97 ± 0.482 ng/mg, respectively. The lyophilized AM contained 217.74 ± 8.78 µg/mg collagen, 14.4 ± 1.56 µg/mg GAGs, 43.2 ± 6.8 µg/mg elastin, and 234.6 ± 21.5 ng/mg DNA, with VEGF and bFGF levels of 28.12 ± 7.6 and 13.3 ± 6.89 ng/mg, respectively. SEM revealed a monolayer with poorly defined borders in fresh AM, whereas lyophilized AM displayed a well-defined apical border with few microvilli. Lyophilized AM-conditioned media promoted greater endothelial cell and fibroblast proliferation. Compared with those in the fresh AM and control groups, wounds treated with lyophilized AM healed faster, with narrower edges and more pronounced re-epithelization and collagen remodeling at 1-, 3-, and 5-weeks post-wounding. Histopathology revealed quicker granulation and inflammatory cell infiltration in the first week for lyophilized AM, and better re-epithelization and collagen remodeling in subsequent stages. In conclusion, the amniotic membrane, particularly in its lyophilized form, offers significant benefits for skin wound healing due to its bioactivity, availability, and cost-effectiveness.

Stromal Cells in Early Inflammation-Related Pancreatic Carcinogenesis-Biology and Its Potential Role in Therapeutic Targeting

The stroma of healthy pancreases contains various non-hematopoietic, non-endothelial mesenchymal cells. It is altered by chronic inflammation which in turn is a major contributor to the development of pancreatic adenocarcinoma (PDAC). In PDAC, the stroma plays a decisive and well-investigated role for tumor progression and therapy response. This review addresses the central role of stromal cells in the early inflammation-driven development of PDAC. It focuses on major subpopulations of pancreatic mesenchymal cells, i.e., fibroblasts, pancreatic stellate cells, and multipotent stroma cells, particularly their activation and functional alterations upon chronic inflammation including the development of different types of carcinoma-associated fibroblasts. In the second part, the current knowledge on the impact of activated stroma cells on acinar-to-ductal metaplasia and the transition to pancreatic intraepithelial neoplasia is summarized. Finally, putative strategies to target stroma cells and their signaling in early pancreatic carcinogenesis are reflected. In summary, the current data show that the activation of pancreatic stroma cells and the resulting fibrotic changes has pro- and anti-carcinogenetic effects but, overall, creates a carcinogenesis-promoting microenvironment. However, this is a dynamic process and the therapeutic targeting of specific pathways and cells requires in-depth knowledge of the molecular interplay of various cell types.

Cardiovascular positron emission tomography imaging of fibroblast activation: A review of the current literature

Fibrosis is one of the key healing responses to injury, especially within the heart, where it helps to maintain structural integrity following acute insults such as myocardial infarction. However, if it becomes dysregulated, then fibrosis can become maladaptive, leading to adverse remodelling, impaired cardiac function and heart failure. Fibroblast activation protein is exclusively expressed by activated fibroblasts, the key effector cells of fibrogenesis, and has a unique extracellular domain that is an ideal ligand for novel molecular imaging probes. Fibroblast activation protein inhibitor (FAPI) radiotracers have been developed for positron emission tomography (PET) imaging, demonstrating high selectivity for activated fibroblasts across a range of different pathologies and disparate organ systems. In this review, we will summarise the role of fibroblast activation protein in cardiovascular disease and how FAPI radiotracers might improve the assessment and treatment of patients with cardiovascular diseases.

Muscle physiology in spasticity and muscle stiffness

This paper examines the physiological changes in spastic muscles contributing to spasticity and muscle stiffness, focusing on the underlying mechanisms and their clinical implications. Spasticity, which is prevalent in neurological conditions such as multiple sclerosis, cerebral palsy, spinal cord injury, stroke, and traumatic brain injury, is characterized by disordered sensorimotor control and often results in increased muscle stiffness and resistance to movement. Recent developments in the understanding of spasticity suggest the importance of architectural changes in muscles that may contribute to increased passive resistance, potentiate reflex mechanisms, and progression to fibrosis, with hyaluronan (HA), a glycosaminoglycan, playing a pivotal in modulating the properties of the muscle extracellular matrix (ECM). The hyaluronan hypothesis of muscle stiffness postulates that the accumulation and biophysical alteration of HA in the ECM of muscle increases its viscosity, resulting in increased passive mechanical resistance. This is turn mayincrease muscle sensitivity to stretch, potentiating spasticity, and lead to cellular differentiation of myofibroblasts to fibroblasts ultimately leading to fibrosis and contracture. A deeper understanding of HA's role in ECM dynamics offers promising avenues for novel treatments aimed at mitigating stiffness and preventing long-term disability in patients with spasticity.

Therapeutic effects of a femtosecond laser on rheumatoid arthritis in rats: Attenuation of oxidative stress and inflammation

Rheumatoid arthritis (RA) is a chronic inflammatory autoimmune disorder characterized by joint damage and persistent pain. Despite advances in treatment, there is currently no definitive cure for RA, and the side effects of available medications often limit their long-term use. Therefore, this study investigated the therapeutic potential of femtosecond laser irradiation (FSL) in treating arthritis induced by complete Freund's adjuvant (CFA) in a rat model. Twenty-four adult male Wistar rats were divided into four groups. Groups 1 and 2 served, respectively, as the negative control and positive FSL irradiated group (at a wavelength of 830 nm, a power of 200 mW, an exposure time of 120 s, a beam area of 0.8 cm2 (0.5 cm radius), a power density of 0.25 W/cm2, and an energy dose of 30 J/cm2). Group 3 represented the arthritic group that received a single subcutaneous injection of 0.1 ml CFA. Group 4 was the arthritic rats irradiated with FSL (two sessions/week) for three weeks. Morphological changes including edema and swelling that increased the circumference of the right hind paw, as well as histological alterations marked by cellular infiltration, synovitis, and cartilage degeneration confirmed RA in the ankle joints. These changes correlated with elevated levels of rheumatoid factor (RF), TNF-α, and IL-6, and augmented oxidative stress associated with a declined antioxidant defense system. Exposure to FSL ameliorated the morphological and histopathological changes in the ankle joint, decreased RF, TNF-α, IL-6, and MDA, and increased GSH and GPx. In conclusion, femtosecond laser irradiation showed antioxidant and anti-inflammatory properties and exerted regenerative effects on the histological features of the ankle in a rheumatoid arthritis rat model.

Ogerin induced activation of Gpr68 alters tendon healing

Satisfactory outcomes after acute tendon injuries are hampered by a fibrotic healing response. As such, modulation of extracellular matrix deposition and remodeling represents an important intervention point to improve healing. During fibrosis, matrix is deposited and remodeled by activated fibroblasts and/or myofibroblasts. Recent work has demonstrated that Ogerin, a positive allosteric modulator of the orphan proton-sensing GPCR, GPR68, can modulate fibroblast ↔ myofibroblast dynamics in multiple fibroblast populations, including blunting myofibroblast differentiation and facilitating reversion of mature myofibroblasts to a basal fibroblast state in vitro. In the present study, we tested the ability of Ogerin to modulate tendon fibroblast ↔ myofibroblast behavior in vitro and in vivo. Consistent with prior work, Ogerin can both blunt TGF-β induced tenocyte → myofibroblast differentiation and partially revert mature myofibroblasts to a basal tenocyte state. However, Ogerin treatment from days 8-12 after tendon repair surgery did not inhibit myofibroblast differentiation, and Ogerin treatment from post-operative days 24-28 did not induce myofibroblast reversion. Moreover, while we expected Ogerin treatment from days 8-12 to impair healing due to blunted extracellular matrix formation, Ogerin treatment improved tendon mechanical properties and altered cell transcriptional profiles and communication patterns in a way that suggests accelerated remodeling and resolution of the repair response, identifying Ogerin as a novel therapeutic approach to improve the tendon healing process.

Modeling Stromal Cells Inside the Tumor Microenvironment of Ovarian Cancer: In Vitro Generation of Cancer-Associated Fibroblast-Like Cells and Their Impact in a 3D Model

The tumor microenvironment (TME) is the combination of cells and factors that promotes tumor progression, and cancer-associated fibroblasts (CAFs) are a key component within TME. CAF originates from various stromal cells and is activated by factors such as transforming growth factor-beta (TGF-β) secreted by tumor cells, favoring chemoresistance and metastasis. Recent publications have underlined plasticity and heterogeneity and their strong contribution to the reactive stroma within the TME. Our study aimed to replicate the TME's structure by creating a 3D in vitro model of ovarian cancer (OC). By incorporating diverse tumor and stromal cells, we simulated a physiologically relevant environment for studying CAF-like cell behavior within tumor spheroids in a context-dependent manner. CAF-like cells were generated by exposing human dermal fibroblasts to OC cell line conditioned media in the presence or absence of TGF-β. Herein, we found that different stimuli induce the generation of heterogeneous populations of CAF-like cells. Notably, we observed the ability of CAF-like cells to shape the intratumoral architecture and to contribute to functional changes in tumor cell behavior. This study highlights the importance of precise assessment of CAF for potential therapeutic interventions and further provides a reliable model for investigating novel therapeutic targets in OC.

TRPC3 inhibition induces myofibroblast differentiation in diabetic dermal fibroblasts

Diabetic wounds present a significant healthcare challenge due to impaired healing mechanisms, with dermal fibroblasts playing a crucial role in tissue repair. This study investigates the role of transient receptor potential canonical-3 (TRPC3) in the dysfunction of diabetic fibroblasts and explores the therapeutic potential of TRPC3 inhibition. Findings reveal that TRPC3 expression is significantly elevated in diabetic dermal fibroblasts, which correlates with suppressed transforming growth factor-beta (TGF-β) signaling and impaired differentiation into myofibroblasts. Inhibiting TRPC3 effectively restores fibroblast functionality by upregulating TGF-β1 and its downstream effector, SMAD4. This restoration enhances the expression of key myofibroblast markers, such as α-smooth muscle actin (ACTA2) and type I collagen (COL1a1), which are essential for wound contraction and extracellular matrix remodeling. These results establish TRPC3 as a critical regulator of fibroblast activity and present TRPC3 inhibition as a promising therapeutic strategy for improving wound healing in diabetic patients.

Extracellular Matrix Microstructures Modulate Hepatic Methionine Cycle and Methylations

The field of mechanobiology has grown in the past decade, but limited studies investigate how the extracellular matrix affects the cell metabolome. The methionine cycle involves the catabolism and regeneration of methionine through the donation and recovery of a single methyl group; this methyl group can methylate DNA, RNA, and proteins to alter gene expression and protein-protein interactions. Through studying cells cultured on fibrous (mimicking healthy extracellular matrice (ECM)) and flat (mimicking severely fibrotic ECM) substrates, we observed an increase in methionine cycle enzyme expression in cells on the flat substrate. We also present how the methionine cycle is modulated by the ECM through transmembrane protein integrin β1. By inhibiting integrin activation through the ligand-mimicking peptide RGD, we observed that the methionine cycle was protected from alteration. The results presented provide insight into possible therapeutic targets for fibrotic diseases and knowledge of mechanisms by which the ECM alters cell processes.

The effects of decellularized amniotic membrane and Wharton's jelly on the healing of experimental skin wounds in rats

Several studies have focused on novel therapeutic strategies for extensive skin lesions aiming to improve healing quality and reduce treatment duration. In this context, the use of amniotic membrane (AM) and Wharton's jelly (WJ) emerges as promising alternatives. Full-thickness dorsal skin wounds were created in 21 Wistar rats, randomly divided into three groups: control (C), AM - covered by AM and WJ - covered by WJ. Wound contraction rate was measured weekly. On day 28, histochemical (Picrosirius red) and immunohistochemical analyses matrix metalloproteinase-9 (MMP-9), transforming growth factor beta (TGF-β), and alpha-smooth muscle actin (α-SMA) were performed. On day seven, wound contraction rate was higher in the AM group (38.8%), followed by the WJ (27.4%) and control (26.5%) with statistically significance. During the first 14 days, the AM group maintained the highest contraction rate, followed by the control and WJ groups. However, by day 21, wound contraction rates increased in the order of WJ to AM to control groups (85.6%, 87.0%, and 91.1%) with statistically significance. Type I collagen predominated across all groups, without statistically significant differences among them. TGF-β expression significantly increased from WJ to AM to control groups (19.75%, 26.00%, and 36.56%) with statistically significance. MMP-9 and α-SMA expressions decreased from control to WJ to AM groups, but no significant differences were observed. Both AM and WJ enhanced early wound contraction and may support skin repair by attenuating fibrotic signaling. These findings highlight the potential of AM and WJ as biomaterials for promoting tissue regeneration at epithelial barriers.

EDA Fibronectin Microarchitecture and YAP Translocation during Wound Closure

Fibronectin (Fn) is an extracellular matrix glycoprotein with mechanosensitive structure-function. Extra domain A (EDA) Fn, a Fn isoform, is not present in adult tissue but is required for tissue repair. Curiously, EDA Fn is linked to both regenerative and fibrotic tissue repair. Given that Fn mechanoregulates cell behavior, EDA Fn organization during wound closure might play a role in mediating these differing responses. One mechanism by which cells sense and respond to their microenvironment is by activating a transcriptional coactivator, yes-associated protein (YAP). Interestingly, YAP activity is not only required for wound closure but similarly linked to both regenerative and fibrotic repair. Therefore, this study aims to evaluate how, during normal and fibrotic wound closure, EDA Fn organization might modulate YAP translocation by culturing human dermal fibroblasts on polydimethylsiloxane substrates mimicking normal (soft: 18 kPa) and fibrotic (stiff: 146 kPa) wounded skin. On stiffer substrates mimicking fibrotic wounds, fibroblasts assembled an aligned EDA Fn matrix comprising thinner fibers, suggesting increased microenvironmental tension. To evaluate if cell binding to the EDA domain of Fn was essential to overall matrix organization, fibroblasts were treated with Irigenin, which inhibits binding to the EDA domain within Fn. Blocking adhesion to EDA led to randomly organized EDA Fn matrices with thicker fibers, suggesting reduced microenvironmental tension even during fibrotic wound closure. To evaluate whether YAP signaling plays a role in EDA Fn organization, fibroblasts were treated with CA3, which suppresses YAP activity in a dose-dependent manner. Treatment with CA3 also led to randomly organized EDA Fn matrices with thicker fibers, suggesting a potential connected mechanism of reducing tension during fibrotic wound closure. Next, YAP activity was assessed to evaluate the impact of EDA Fn organization. Interestingly, fibroblasts migrating on softer substrates mimicking normal wounds increased YAP activity, but on stiffer substrates, they decreased YAP activity. When fibroblasts on stiffer substrates were treated with Irigenin or CA3, fibroblasts increased YAP activity. These results suggest that there may be disrupted signaling between EDA Fn organization and YAP translocation during fibrotic wound closure that could be restored when reestablishing normal EDA Fn matrix organization to instead drive regenerative wound repair.

Fibromodulin selectively accelerates myofibroblast apoptosis in cutaneous wounds by enhancing interleukin 1β signaling

Activated myofibroblasts deposit extracellular matrix material to facilitate rapid wound closure that can heal scarlessly during fetal development. However, adult myofibroblasts exhibit a relatively long life and persistent function, resulting in scarring. Thus, understanding how fetal and adult tissue regeneration differs may serve to identify factors that promote more optimal wound healing in adults with little or less scarring. We previously found that matricellular proteoglycan fibromodulin is one such factor promoting more optimal repair, but the underlying molecular and cellular mechanisms for these effects have not been fully elucidated. Here, we find that fibromodulin induces myofibroblast apoptosis after wound closure to reduce scarring in small and large animal models. Mechanistically, fibromodulin accelerates and prolongs the formation of the interleukin 1β-interleukin 1 receptor type 1-interleukin 1 receptor accessory protein ternary complex to increase the apoptosis of myofibroblasts and keloid- and hypertrophic scar-derived cells. As the persistence of myofibroblasts during tissue regeneration is a key cause of fibrosis in most organs, fibromodulin represents a promising, broad-spectrum anti-fibrotic therapeutic.

SHP099-containing multi-targeting hydrogel promotes rapid skin reconstruction through modulating a variety of cells

Introduction

Adult wound scarring result in functional skin deficits. However, the development of effective measures to modulate the entire wound healing to encourage the skin function reconstruction is still a clinical challenge, as multiple cells are involved in wound healing hierarchically. Hydrogel scaffolds with long-lasting local release provide new insights into the clinical relevance of entire wound healing.

Methods

Herein, a multi-targeting hydrogel loaded with SHP099 (Gel-SHP) is designed to modulate multiple cells during wound repair.

Results

Our results show that Gel-SHP promotes rapid reconstruction of wound skin by modulating macrophages in the inflammatory stage, fibroblasts in the regeneration stage and smooth muscle cells in the remodelling stage. Gel-SHP could increase M2 macrophage differentiation and remodel the dermal shell of hair follicles through in situ release. Moreover, Gel-SHP may modulate myofibroblasts to promote wound contraction through SHP099-scaffold synergistic interactions.

Discussion

Our results provide new insights into the design of functional hydrogels for tissue regeneration applications. Gel-SHP as a promising tool could provide new clues and new research paradigms for future studies and understanding of the wound healing process and dermal shell formation.

Ferroptosis in organ fibrosis: Mechanisms and therapeutic approaches

Ferroptosis, a form of iron-dependent regulated cell death, has emerged as a critical mechanism in the pathogenesis of organ fibrosis. This review aims to provide an overview of the molecular mechanisms underlying ferroptosis and its contribution to fibrosis in various organs, including the liver, lung, heart, and kidneys. We explore how dysregulated iron metabolism, lipid peroxidation, and oxidative stress contribute to ferroptosis and subsequent tissue damage, promoting the progression of fibrosis. In addition, we highlight the complex interplay between ferroptosis and other cellular processes such as apoptosis, necrosis, and inflammation in the fibrotic microenvironment. Furthermore, this review discusses current therapeutic strategies targeting ferroptosis, including iron chelation, antioxidants, and modulators of lipid peroxidation. We also examine ongoing clinical and preclinical studies aimed at translating these findings into viable treatments for fibrotic diseases. Understanding the role of ferroptosis in organ fibrosis offers novel therapeutic opportunities, with the potential to mitigate disease progression and improve patient outcomes.

Benign non-immune cells in tumor microenvironment

The tumor microenvironment (TME) is a highly complex and continuous evolving ecosystem, consisting of a diverse array of cellular and non-cellular components. Among these, benign non-immune cells, including cancer-associated fibroblasts (CAFs), adipocytes, endothelial cells (ECs), pericytes (PCs), Schwann cells (SCs) and others, are crucial factors for tumor development. Benign non-immune cells within the TME interact with both tumor cells and immune cells. These interactions contribute to tumor progression through both direct contact and indirect communication. Numerous studies have highlighted the role that benign non-immune cells exert on tumor progression and potential tumor-promoting mechanisms via multiple signaling pathways and factors. However, these benign non-immune cells may play different roles across cancer types. Therefore, it is important to understand the potential roles of benign non-immune cells within the TME based on tumor heterogeneity. A deep understanding allows us to develop novel cancer therapies by targeting these cells. In this review, we will introduce several types of benign non-immune cells that exert on different cancer types according to tumor heterogeneity and their roles in the TME.

Cancer-associated fibroblasts in breast cancer in the single-cell era: Opportunities and challenges

Breast cancer is a leading cause of morbidity and mortality in women, and its progression is closely linked to the tumor microenvironment (TME). Cancer-associated fibroblasts (CAFs), key components of the TME, play a crucial role in promoting tumor growth by driving cancer cell proliferation, invasion, extracellular matrix (ECM) remodeling, inflammation, chemoresistance, and immunosuppression. CAFs exhibit considerable heterogeneity and are classified into subgroups based on different combinations of biomarkers. Single-cell RNA sequencing (scRNA-seq) enables high-throughput and high-resolution analysis of individual cells. Relying on this technology, it is possible to cluster complex CAFs according to different biomarkers to analyze the specific phenotypes and functions of different subpopulations. This review explores CAF clusters in breast cancer and their associated biomarkers, highlighting their roles in disease progression and potential for targeted therapies.

Survival of periodontal ligament myofibroblasts after short-term mechanical strain in rats and in vitro: Could myofibroblasts contribute to orthodontic relapse?

OBJECTIVES

To investigate in vivo whether myofibroblasts formed in the PDL after exposure to short-term high experimental orthodontic forces in rats survive. To study in vitro whether human PDL fibroblasts can differentiate into myofibroblasts and survive when chemical or mechanical stimuli are removed.

DESIGN

Nine 6-week-old male Wistar rats were used in this experiment. Rat molars were exposed to high but rapidly decreasing experimental orthodontic forces by applying a rubber band and analyzed for the presence of myofibroblasts using ASMA staining. In vitro, human periodontal ligament (PDL) fibroblasts were exposed to transforming growth factor β1 (TGFβ1) and/or mechanical stress and monitored for myofibroblast formation and survival after these stimuli were abrogated.

RESULTS

In vivo exposure to orthodontic forces strongly induced myofibroblast formation in the stretched regions of the PDL. Furthermore, many PDL myofibroblasts remained present 6 days after exposure to these short-term high orthodontic forces. Human PDL fibroblasts were shown to differentiate into myofibroblasts after 2 days of TGFβ1 exposure and survive for at least 2 more days after removing chemical stimuli (TGFβ1) or mechanical strain. Under in vitro conditions, both TGFβ1 and mechanical strain for 3 days promoted (myo)fibroblast formation, and these cells persisted for 3 more days after the removal of both stimuli.

CONCLUSIONS

PDL myofibroblasts survive after the removal of mechanical strain in vivo and in vitro. This supports the hypothesis that myofibroblasts, which form in response to mechanical strain and chemical cues in the periodontal ligament (PDL), play a role in relapse following orthodontic tooth movement.

An anti-inflammatory and anti-fibrotic Janus hydrogel for preventing postoperative peritoneal adhesion

Postoperative peritoneal adhesion (PPA) is pathological tissue hyperplasia between surgical wounds and nearby organs. Currently, traditional double-sided bioadhesives are limited in preventing PPA due to the indiscriminate adhesive properties and the poor interaction with wet tissues. Herein, we developed a Janus hydrogel, named PAA-Cos, by using the polycationic carbohydrate polymer of chitooligosaccharide (Cos) and the polyanionic polymer of polyacrylic acid (PAA). The adhesive layer of Janus hydrogels could adhere to wet tissue tightly due to surfaces composed of carboxyls, and the positively charged biomaterial (Cos) neutralized carboxyls on one side of PAA hydrogel to form Janus hydrogels. Moreover, PAA-Cos can further load with ligustrazine hydrochloride (Ligu), a pharmaceutical compound with anti-inflammatory and anti-fibrotic effects, finally obtaining PAA-Cos@Ligu. After the application of PAA-Cos@Ligu on the surgical trauma, the bottom surface can adhere to wet tissues robustly to restore the wound, while the top surface acts as a physical barrier with antiadhesive effects to avoid PPA. PAA-Cos@Ligu also exhibited anti-inflammatory effects by promoting M2 macrophage polarization, inhibiting the myofibroblast-like differentiation of peritoneal mesothelial cells, and blocking the TGF-β/Smad2/3 signaling pathway to hinder collagen deposition. Our findings suggest that PAA-Cos@Ligu has great potential as an anti-adhesion candidate with biocompatibility and ease of preparation.

Modelling the spatiotemporal dynamics of senescent cells in wound healing, chronic wounds, and fibrosis

Cellular senescence is known to drive age-related pathology through the senescence-associated secretory phenotype (SASP). However, it also plays important physiological roles such as cancer suppression, embryogenesis and wound healing. Wound healing is a tightly regulated process which when disrupted results in conditions such as fibrosis and chronic wounds. Senescent cells appear during the proliferation phase of the healing process where the SASP is involved in maintaining tissue homeostasis after damage. Interestingly, SASP composition and functionality was recently found to be temporally regulated, with distinct SASP profiles involved: a fibrogenic, followed by a fibrolytic SASP, which could have important implications for the role of senescent cells in wound healing. Given the number of factors at play a full understanding requires addressing the multiple levels of complexity, pertaining to the various cell behaviours, individually followed by investigating the interactions and influence each of these elements have on each other and the system as a whole. Here, a systems biology approach was adopted whereby a multi-scale model of wound healing that includes the dynamics of senescent cell behaviour and corresponding SASP composition within the wound microenvironment was developed. The model was built using the software CompuCell3D, which is based on a Cellular Potts modelling framework. We used an existing body of data on healthy wound healing to calibrate the model and validation was done on known disease conditions. The model clearly shows how differences in the spatiotemporal dynamics of different senescent cell phenotypes lead to several distinct repair outcomes. These differences in senescent cell dynamics can be attributed to variable SASP composition, duration of senescence and temporal induction of senescence relative to the healing stage. The range of outcomes demonstrated strongly highlight the dynamic and heterogenous role of senescent cells in wound healing, fibrosis and chronic wounds, and their fine-tuned control. Further specific data to increase model confidence could be used to explore senolytic treatments in wound disorders.

Imaging-based biomechanical parameters for assessing risk of aortic dissection and rupture in thoracic aortic aneurysms

OBJECTIVES

Imaging-based methods of measuring aortic biomechanics may provide superior and a more personalized in vivo risk assessment of patients with thoracic aortic aneurysms compared to traditional aortic size criteria such as maximal aortic diameter. We aim to summarize the data on in vivo imaging techniques for evaluation of aortic biomechanics.

METHODS

A thorough search of literature was conducted in MEDLINE, EMBASE and Google Scholar for evidence of various imaging-based biomechanics techniques. All imaging modalities were included. Data involving preclinical/animal models or exclusively focussed on abdominal aortic aneurysms were excluded.

RESULTS

The various imaging-based biomechanical parameters can be divided into categories of increasing complexity: strain-based, stiffness-based and computational modelling-derived. Strain-based and stiffness-based parameters are more simply calculated and can be derived using multiple imaging modalities. Initial studies are promising towards linking these parameters with clinically relevant end-points, including aortic dissection, though work is required for standardization. Computationally derived parameters provide detail of stress exerted on the aortic wall with great spatial resolution. However, they are highly dependent on the assumptions applied to the models, such as material properties of the aortic wall.

CONCLUSIONS

Imaging-based aortic biomechanics represent a major technical advancement for personalized in vivo risk stratification of patients with ascending thoracic aortic aneurysm. The next steps in clinical translation require large-scale validation of these markers towards predicting aortic dissections and comparison against the gold standard ex vivo aortic biomechanics as well as development of a user-friendly, low-cost algorithm that can be widely adopted.

From Bench to Bedside: Translational Approaches to Cardiotoxicity in Breast Cancer, Lung Cancer, and Lymphoma Therapies

Cardiotoxicity represents a critical challenge in cancer therapy, particularly in the treatment of thoracic tumors, such as lung cancer and lymphomas, as well as breast cancer. These malignancies stand out for their high prevalence and the widespread use of cardiotoxic treatments, such as chemotherapy, radiotherapy, and immunotherapy. This work underscores the importance of preclinical models in uncovering the mechanisms of cardiotoxicity and developing targeted prevention and mitigation strategies. In vitro models provide valuable insights into cellular processes, enabling the observation of changes in cell viability and function following exposure to various drugs or ionizing radiation. Complementarily, in vivo animal models offer a broader perspective, allowing for evaluating of both short- and long-term effects and a better understanding of chronic toxicity and cardiac diseases. By integrating these approaches, researchers can identify potential mechanisms of cardiotoxicity and devise effective prevention strategies. This analysis highlights the central role of preclinical models in advancing knowledge of cardiotoxic effects associated with common therapeutic regimens for thoracic and breast cancers.

Cancer‑associated fibroblasts: a pivotal regulator of tumor microenvironment in the context of radiotherapy

BACKGROUND

In the course of tumor treatment, radiation therapy (RT) not only kills cancer cells, but also induces complex biological effects in non-malignant cells around cancer cells. These biological effects such as angiogenesis, changes in stromal composition and immune cell infiltration remodel the tumor microenvironment (TME). As one of the major components of the TME, Cancer‑associated fibroblasts (CAFs) are not only involved in tumorigenesis, progression, recurrence, and metastasis but also regulate the tumor-associated immune microenvironment. CAFs and tumor cells or immune cells have complex intercellular communication in the context of tumor radiation.

MAIN CONTENT

Different cellular precursors, spatial location differences, absence of specific markers, and advances in single-cell sequencing technology have gradually made the abundant heterogeneity of CAFs well known. Due to unique radioresistance properties, CAFs can survive under high doses of ionizing radiation. However, radiation can induce phenotypic and functional changes in CAFs and further act on tumor cells and immune cells to promote or inhibit tumor progression. To date, the effect of RT on CAFs and the effect of irradiated CAFs on tumor progression and TME are still not well defined.

CONCLUSION

In this review, we review the origin, phenotypic, and functional heterogeneity of CAFs and describe the effects of RT on CAFs, focusing on the mutual crosstalk between CAFs and tumor or immune cells after radiation. We also discuss emerging strategies for targeted CAFs therapy.

The mechanopathology of the tumor microenvironment: detection techniques, molecular mechanisms and therapeutic opportunities

The mechanical properties of the tumor microenvironment (TME) undergo significant changes during tumor growth, primarily driven by alterations in extracellular (ECM) stiffness and tumor viscoelasticity. These mechanical changes not only promote tumor progression but also hinder therapeutic efficacy by impairing drug delivery and activating mechanotransduction pathways that regulate crucial cellular processes such as migration, proliferation, and resistance to therapy. In this review, we examine the mechanisms through which tumor cells sense and transmit mechanical signals to maintain homeostasis in the biomechanically altered TME. We explore current computational modelling strategies for mechanotransduction pathways, highlighting the need for developing models that incorporate additional components of the mechanosignaling machinery. Furthermore, we review available methods for measuring the mechanical properties of tumors in clinical settings and strategies aiming at restoring the TME and blocking deregulated mechanotransduction pathways. Finally, we propose that proper characterization and a deeper understanding of the mechanical landscape of the TME, both at the tissue and cellular levels, are essential for developing therapeutic strategies that account for the influence of mechanical forces on treatment efficacy.

ARP2/3 complex affects myofibroblast differentiation and migration in pancreatic ductal adenocarcinoma

The ARP2/3 complex, which orchestrates actin cytoskeleton organization and lamellipodia formation, has been implicated in the initiation of pancreatic ductal adenocarcinoma (PDAC). This study aims to clarify its impact on the activity of cancer-associated fibroblasts (CAFs), key players in PDAC progression, and patient outcomes. Early pancreatic carcinogenesis was modeled in p48Cre; LSL-KrasG12D mice with caerulein-induced pancreatitis, complemented by in vitro studies on human immortalized pancreatic stellate cells (PSCs) and primary PDAC-derived CAFs. Data were gained from microarray analysis, RNA sequencing (RNA-seq), and single-cell RNA sequencing (sc-RNA-seq), with subsequent bioinformatics analysis. We uncovered a specific transcriptional signature associated with fibroblast migration in early pancreatic carcinogenesis and linked it to poor survival in patients with PDAC. A pivotal role of the ARP2/3 complex in CAF migration was identified. Inhibition of the ARP2/3 complex markedly decreased CAF motility and induced significant morphological changes in vitro. Furthermore, its inhibition also hindered TGFβ1-mediated myofibroblastic CAF differentiation but had no effect on IL-1-mediated inflammatory CAF differentiation. Our findings position the ARP2/3 complex as central to the migration and differentiation of myofibroblastic CAF. Targeting this complex presents a promising new therapeutic avenue for PDAC treatment.

Neutrophil Heterogeneity in Wound Healing

Neutrophils are the most abundant type of immune cells and also the most underestimated cell defenders in the human body. In fact, their lifespan has also been extensively revised in recent years, going from a half-life of 8-10 h to a longer lifespan of up to 5.4 days in humans; it has been discovered that their mechanisms of defense are multiple and finely modulated, and it has been suggested that the heterogeneity of neutrophils occurs as well as in other immune cells. Neutrophils also play a critical role in the wound healing process, and their involvement is not limited to the initial stages of defense against pathogens, but extends to the inflammatory phase of tissue reconstruction. Neutrophil heterogeneity has recently been reported at the presence of distinct subtypes expressing different functional states, which contribute uniquely to the different phases of innate immunity and wound healing. This heterogeneity can be induced by the local microenvironment, by the presence of specific cytokines and by the type of injury. The different functional states of neutrophils enable a finely tuned response to injury and stress, which is essential for effective healing. Understanding the functional heterogeneity of neutrophils in wound healing can unveil potential pathological profiles and therapeutic targets. Moreover, the understanding of neutrophil heterogeneity dynamics could help in designing strategies to manage excessive inflammation or impaired healing processes. This review highlights the complexity of neutrophil heterogeneity and its critical roles throughout the phases of wound healing.

Cross-Talk Between Cancer and Its Cellular Environment-A Role in Cancer Progression

The tumor microenvironment is a dynamic and complex three-dimensional network comprising the extracellular matrix and diverse non-cancerous cells, including fibroblasts, adipocytes, endothelial cells and various immune cells (lymphocytes T and B, NK cells, dendritic cells, monocytes/macrophages, myeloid-derived suppressor cells, and innate lymphoid cells). A constantly and rapidly growing number of studies highlight the critical role of these cells in shaping cancer survival, metastatic potential and therapy resistance. This review provides a synthesis of current knowledge on the modulating role of the cellular microenvironment in cancer progression and response to treatment.

Effects of Kinesio Tape on Vascularity, Pliability, and Height of the Hypertrophic Scar in Burns Patients: A Randomized Pilot Clinical Trial

Deep burns damage the reticular dermis and may lead to the formation of hypertrophic scars. Compression therapy reduces local vascularity and realigns collagen fibers, resulting in esthetic and functional improvements. This study evaluated the effect of Kinesio tape compression with maximum mechanical tension on vascularity, pliability, and the height of hypertrophic scars following deep burns. A single-blind, randomized pilot clinical trial was carried out. The elastic compression of Kinesio tape was applied at maximum stretch in the intervention group (n = 11) and no stretch in the sham group (n = 11). Vascularity, pliability, and height (the primary outcomes) were evaluated at 0, 45, and 90 days using the Vancouver Scar Scale (VSS). The association between the VSS scores, the intervention and the evaluation moment were analyzed using linear mixed-effects regression models, while comparisons of means between the groups were performed using the Student's t-test. Significance was set at 5%. The mean VSS scores were similar between the groups. Significant improvement occurred in both groups when posttreatment and baseline scores were compared. No further improvement was found in the vascularity, pliability, or height of hypertrophic scars resulting from deep burns when an elastic compression of Kinesio tape was used at maximum tension compared to lesser mechanical tension.

Development of a Self-Deploying Extra-Aortic Compression Device for Medium-Term Hemodynamic Stabilization: A Feasibility Study

Hemodynamic stabilization is crucial in managing acute cardiac events, where compromised blood flow can lead to severe complications and increased mortality. Conditions like decompensated heart failure (HF) and cardiogenic shock require rapid and effective hemodynamic support. Current mechanical assistive devices, such as intra-aortic balloon pumps (IABP) and extracorporeal membrane oxygenation (ECMO), offer temporary stabilization but are limited to short-term use due to risks associated with prolonged blood contact. This research presents a novel proof-of-concept soft robotic device designed with the aim of achieving low-risk, medium-term counterpulsation therapy. The device employs a nature-inspired growing mechanism for potentially minimally invasive deployment around the ascending aorta, coupled with hydraulic artificial muscles for aortic compression. It demonstrated a maximum stroke volume of 16.48 ± 0.21 mL (SD, n = 5), outperforming all other non-pneumatic extra-aortic devices. In addition, in vitro tests with a mock circulation loop (MCL) show a drop in aortic end-diastolic pressure by 6.32 mmHg and enhance coronary flow under mild aortic stenosis, which attenuate the device's assistive effect. These findings highlight the device's strong potential for optimization as a promising solution to improve outcomes for hemodynamically unstable HF patients.

Glial cell line-derived neurotrophic factor and its role in attenuating renal fibrosis: a review

Chronic kidney disease is estimated to affect approximately 10 to 15% of the Chinese population. Renal fibrosis is characterized by progressive extracellular matrix deposition in the kidney parenchyma with eventual tissue scarring and inevitable deterioration of renal function. Vascular rarefaction, glomerulosclerosis, interstitial inflammation, and fibrogenesis are associated with or contribute to renal fibrosis. Recent studies have revealed that glial cell-derived neurotrophic factor (GDNF) is involved in kidney morphogenesis and amelioration of renal injury. Ideal therapies targeting the pathogenesis of renal fibrosis should have the potential to inhibit glomerular and tubulointerstitial fibrosis by targeting multiple pathological events. GDNF plays a unique role in both renal development and improvement of renal fibrosis, and GDNF kidney receptors and signaling pathways can ameliorate renal apoptosis and inflammation. Our work contributes to the establishment of GDNF as an emerging therapy that can increase the effectiveness of currently used interventions to improve renal fibrosis. This literature review focuses on the important role of GDNF in renal development and its relationship with renal fibrosis.

Variations in ECM Topography, Fiber Alignment, Mechanical Stiffness, and Cellular Composition Between Ventral and Dorsal Ligamentum Flavum Layers: Insights Into Hypertrophy Pathogenesis

Background

Previous studies have suggested that changes in the composition of the extracellular matrix (ECM) play a significant role in the development of ligamentum flavum hypertrophy (LFH) and the histological differences between the ventral and dorsal layers of the hypertrophied ligamentum flavum. Although LFH is associated with increased fibrosis in the dorsal layer, comprehensive research exploring the characteristics of the ECM and its mechanical properties in both regions is limited. Furthermore, the distribution of fibrosis-associated myofibroblasts within LFH remains poorly understood. This study aimed to bridge the existing knowledge gap concerning the intricate relationships between ECM characteristics, mechanical properties, and myofibroblast expression in LFH.

Methods

Histological staining, scanning electron microscopy, and atomic force microscopy were used to analyze the components, alignment, and mechanical properties of the ECM. Immunostaining and western blot analyses were performed to assess the distribution of myofibroblasts in LF tissues.

Results

There were notable differences between the dorsal and ventral layers of the hypertrophic ligamentum flavum. Specifically, the dorsal layer exhibited higher collagen content and disorganized fibrous alignment, resulting in reduced stiffness. Immunohistochemistry analysis revealed a significantly greater presence of α-smooth muscle actin (αSMA)-stained cells, a marker for myofibroblasts, in the dorsal layer.

Conclusions

This study offers comprehensive insights into LFH by elucidating the distinctive ECM characteristics, mechanical properties, and cellular composition disparities between the ventral and dorsal layers. These findings significantly enhance our understanding of the pathogenesis of LFH and may inform future research and therapeutic strategies.

Development of a biomarker panel for cell characterization intended for cultivated meat

Cultivated meat has in recent years been suggested as a sustainable alternative to produce meat at large-scale. Several aspects of cultivated meat production have demonstrated significant progress. However, there are still many questions regarding the cell culture, media composition, and the production itself to be answered and optimized. Finding good starter cell populations is a challenge to address and requires robust tools to characterize the cell populations. Detailed analysis is required to identify each type of cell within the skeletal muscle niche leads to optimized cultivated meat production at large-scale. In this study, we developed a set of biomarkers, using digital droplet PCR (ddPCR) and Immunofluorescence (IF) staining, to identify specific cell types within a heterogeneous cell population isolated from skeletal muscle tissue. We showed that combining Neural Cell Adhesion Molecule (NCAM), Calponin 1 (CNN1), and Fibronectin (FN), can be a powerful approach to predict the growth of skeletal myotubes, smooth muscle mesenchymal cells (SMMCs), and myofibroblasts, respectively. Moreover, early cell-cell interactions of fibroblastic cells were observed to be triggered through thin actin filaments containing CNN1 protein, to form, subsequently, myofibroblast networks. Besides, Myogenic Differentiation 1 (MyoD) is the key marker to detect skeletal muscle growth, whereas Myogenic Factor 5 (MyF5) can be expressed in myogenic and non-myogenic cells. MyF5 was detected at differentiation stages within the myotube nuclei, suggesting an unknown role during myotube formation.

Pathological and molecular insights into intravenous leiomyomatosis: an integrative multi-omics study

Intravenous leiomyomatosis (IVL) is a histologically well differentiated smooth muscle tumor with aggressive behavior, capable of extending throughout the venous system. Understanding how IVL occurs and develops is really important for diagnosing and treating it. Unfortunately, because IVL is quite rare, there aren't many comprehensive studies available. In our research, we carried out an extensive multi-omics study, gathering tissue samples from IVL cases, uterine fibroid, and normal myometrium. The single-cell RNA sequencing analysis revealed a notable difference in cell composition between IVL and uterine fibroid. Additionally, H&E staining demonstrated more frequent hydropic changes and hyalinization in IVL tissues, along with a reduced vascular density compared to both normal myometrium and uterine fibroid. In our proteomics analysis of eight paired samples of IVL and normal myometrium fresh frozen tissue, we identified proteins that were differentially expressed, mainly related to focal adhesions and regulation of the actin cytoskeleton. The most frequently involved chromosomes included deletions in 10q22.2, 10q24.32, 13q14, and 13q21-31. Correlation analyses highlighted chromosome 10q as the most frequent cytoband, with corresponding proteins involved in regulating focal adhesions and the cytoskeleton. Integrated analysis between pathological and clinical characteristics indicated that chromosome 10q deletion and vascular morphology in IVL could serve as important markers predicting aggressive behavior. Our study sheds light on the pathological and molecular changes linked to IVL, which could pave the way for new treatment approaches.

Novel therapeutic strategy for intractable keloids: suppression of intracellular mechanotransduction and actin polymerization via Rho-kinase pathway inhibition

BACKGROUND

Keloid is a dermal fibrotic disorder characterized by excessive extracellular matrix production by fibroblasts. Despite the significance of mechanostimulation in fibrotic diseases, its association with keloid pathophysiology or treatment remains unexplored.

OBJECTIVES

To investigate the role of mechanical force in keloid formation and elucidate the significance of Rho-associated coiled-coil-containing kinase 1 (ROCK1) as a mechanoresponsive target for keloid treatment.

METHODS

Patient-derived keloid fibroblasts (KFs) were subjected to cyclic stretching ranging from 0% to 20% elongation using a cell-stretching system. We observed the inhibitory effects of the ROCK1 inhibitor Y27632 on KFs and keloid formation. Validation was performed using a keloid xenograft severe combined immune-deficient (SCID) mouse model.

RESULTS

ROCK1 was overexpressed in KFs isolated from patients. Cyclic stretching induced fibroblast proliferation and actin polymerization by activating Rho/ROCK1 signalling. Treatment with Y27632 downregulated fibrotic markers reduced the migration capacity of KFs and induced extensive actin cytoskeleton remodelling. In the keloid xenograft SCID mouse model, Y27632 effectively suppressed keloid formation, mitigating inflammation and fibrosis.

CONCLUSIONS

The ROCK1 inhibitor Y27632 is a promising molecule for keloid treatment, exerting its effects through actin cytoskeleton remodelling and nuclear inhibition of fibrotic markers in keloid pathogenesis.

Pulmozyme Ameliorates LPS-Induced Lung Fibrosis but Provokes Residual Inflammation by Modulating Cell-Free DNA Composition and Controlling Neutrophil Phenotype

Pulmonary fibrosis, a chronic progressive lung disorder, can be the result of previous acute inflammation-associated lung injury and involves a wide variety of inflammatory cells, causing the deposition of extracellular matrix (ECM) components in the lungs. Such lung injury is often associated with excessive neutrophil function and the formation of DNA networks in the lungs, which are also some of the most important factors for fibrosis development. Acute lung injury with subsequent fibrosis was initiated in C57Bl/6 mice by a single intranasal (i.n.) administration of LPS. Starting from day 14, human recombinant DNase I in the form of Pulmozyme for topical administration was instilled i.n. twice a week at a dose of 50 U/mouse. Cell-free DNA (cfDNA), DNase activity, and cell content were analyzed in blood serum and bronchoalveolar lavage fluid (BALF). Inflammatory and fibrotic changes in lung tissue were evaluated by histological analysis. The gene expression profile in spleen-derived neutrophils was analyzed by RT-qPCR. We demonstrated that Pulmozyme significantly reduced connective tissue expansion in the lungs. However, despite the reliable antifibrotic effect, complete resolution of inflammation in the respiratory system of mice treated with Pulmozyme was not achieved, possibly due to enhanced granulocyte recruitment and changes in the nuclear/mitochondrial cfDNA balance in the BALF. Moreover, Pulmozyme introduction caused the enrichment of the spleen-derived neutrophil population by those with an unusual phenotype, combining pro-inflammatory and anti-inflammatory features, which can also maintain lung inflammation. Pulmozyme can be considered a promising drug for lung fibrosis management; however, the therapy may be accompanied by residual inflammation.

Development of a phenotypic screening assay to measure activation of cancer-associated fibroblasts

Background

In cancer metastasis, tumor cells condition distant tissues to create a supportive environment, or metastatic niche, by driving the activation of cancer-associated fibroblasts (CAFs). These CAFs remodel the extracellular matrix, creating a microenvironment that supports tumor growth and compromises immune cell function, enabling cancer cells to evade immune detection. Consequently, targeting the activation of CAFs has been proposed as a therapeutic strategy to hinder metastatic spread. Our objective was to develop the first in vitro phenotypic screening assay capable of assessing this activation process.

Methods

Human primary lung fibroblasts were co-cultured with highly invasive breast cancer cells (MDA-MB-231) to identify changes in the expression of selected genes using RT-qPCR. An In-Cell ELISA (ICE)-based assay using human lung fibroblasts, MDA-MB-231 cells and human monocytes (THP-1 cells) was developed to measure the activation of CAFs. Another ELISA assay was used to measure released osteopontin.

Results

When lung fibroblast were co-cultured with MDA-MB-231 cells, among the 10 selected genes, the genes for osteopontin (SPP1), insulin like growth factor 1 (IGF1), periostin (POSTN) and α-smooth muscle actin (α-SMA, ACTA2) elicited the greatest fold change (55-, 37-, 8- and 5-fold respectively). Since osteopontin, IGF-1 and periostin are secreted proteins and α-SMA is an intracellular cytoskeleton protein, α-SMA was chosen to be the readout biomarker for the ICE assay. When fibroblasts were co-cultured with MDA-MB-231 cells and monocytes in the 96 well ICE assay, α-SMA expression was increased 2.3-fold yielding a robust Z' of 0.56. A secondary, low throughput assay was developed by measuring the release of osteopontin which showed a 6-fold increase when fibroblasts were co-cultured with MDA-MB-231 cells and monocytes.

Discussion

This phenotypic assay is the first to measure the activation of CAFs in a 96-well format, making it suitable for medium-to high-throughput screening of potential therapeutic compounds. By focusing on observable cellular phenotypic changes rather than targeting specific molecular pathways, this assay allows for a broader and unbiased identification of compounds capable of modulating CAF activation.

Long QT syndrome type 3 gain-of-function of Nav1.5 increases ventricular fibroblasts proliferation and pro-fibrotic factors

The long QT syndrome type 3 (LQT3) is a cardiac channelopathy caused by gain-of-function mutations in the SCN5A gene, encoding the sodium channel Nav1.5. As Nav1.5 is expressed in cardiomyocytes but also in cardiac fibroblasts, we investigated whether the LQT3-causing p.ΔQKP1507-1509 (ΔQKP) SCN5A mutation alters cardiac fibroblast phenotype. Primary cultured ventricular fibroblasts from Scn5a+/ΔQKP knock-in mice showed increased proliferation, survival, expression of transforming growth factor-β (TGF-β) and activation of its canonical pathway, and reduced α-smooth muscle actin expression. Ventricular tissue from Scn5a+/ΔQKP mice exhibited augmented fibroblast populations and fibrosis. Inhibiting TGF-β receptor, sodium current or Scn5a expression decreased Scn5a+/ΔQKP fibroblast proliferation, while veratridine increased proliferation of control fibroblasts, mimicking Nav1.5 gain-of-function. Lastly, abnormal calcium signaling underlied the increased proliferation of Scn5a+/ΔQKP fibroblasts. Our study shows that cardiac fibroblasts carrying the ΔQKP-SCN5A mutation exhibit an abnormal, proliferative phenotype, paving the way for better understanding the role of cardiac fibroblasts in LQT3.

Tension-sensitive HOX gene expression in fibroblasts for differential scar formation

BACKGROUND

Scar formation is a common end-point of the wound healing process, but its mechanisms, particularly in relation to abnormal scars such as hypertrophic scars and keloids, remain not fully understood. This study unveils a novel mechanistic insight into scar formation by examining the differential expression of Homeobox (HOX) genes in response to mechanical forces in fibroblasts derived from normal skin, hypertrophic scars, and keloids.

METHODS

We isolated fibroblasts from different scar types and conducted RNA sequencing (RNA-Seq) to identify differential gene expression patterns among the fibroblasts. Computational modeling provided insight into tension alterations following injury, and these findings were complemented by in vitro experiments where fibroblasts were subjected to exogenous tensile stress to investigate the link between mechanical tension and cellular behavior.

RESULTS

Our study revealed differential HOX gene expression among fibroblasts derived from normal skin, hypertrophic scars, and keloids. Computational simulations predicted injury-induced tension reduction in the skin, and in vitro experiments revealed a negative correlation between tension and fibroblast proliferation. Importantly, we discovered that applying mechanical tension to fibroblasts can modulate HOX gene expression, suggesting a pivotal role of mechanical cues in scar formation and wound healing.

CONCLUSION

This study proposes a model wherein successful wound healing and scar formation are critically dependent on maintaining tensional homeostasis in the skin, mediated by tension-sensitive HOX genes. Our findings highlight the potential of targeting mechanotransduction pathways and tension-sensitive HOX gene expression as therapeutic strategies for abnormal scar prevention and treatment, offering a new perspective on the complex process of scar formation.

FAP-targeting biomimetic nanosystem to restore the activated cancer-associated fibroblasts to quiescent state for breast cancer radiotherapy

Cancer associated fibroblasts (CAFs) are one of the most important stromal cells in the tumor microenvironment, playing a pivotal role in the development, recurrence, metastasis, and immunosuppression of cancer and treatment resistance. Here, we developed a core-shell biomimetic nanosystem termed as FAP-C NPs. This system was comprised of 4T1 extracellular vesicles fused with a FAP single-chain antibody fragment to form the biomimetic shell, and PLGA nanoparticles loaded with calcipotriol as the core. The FAP-modified shell endowed this nanosystem with active targeting ability to CAFs. Calcipotriol, a vitamin D analog, can activate the vitamin D receptor expressed on CAFs, promoting their transition from an activated to quiescent state. This process would help to reduce the pro-tumorigenic signals generated by CAFs, inhibit the stemness of cancer cells, and attenuate the inhibitory effect of CAFs on immune cells. The hydrated particle size of FAP-C NPs was approximately 206 nm, with a narrow distribution (polydispersity index < 0.2). The zeta potential of FAP-C NPs was -12.63 ± 0.61 mV. FAP-C NPs can restore CAFs to a quiescent state to shield the function of activated CAFs, inhibit tumor cell stemness, facilitate the maturation of dendritic cell, and relieve the inhibition of CAFs on lymphocytes. Besides, when combined with radiotherapy, this biomimetic nanosystem could inhibit the activation of CAFs, improve the sensitivity to radiation, and stimulate potent anti-tumor immune response with a 2-fold increase in the infiltration of cytotoxic T cells in tumor microenvironment, thereby effectively suppressing tumor growth with the tumor inhibitory rate as 78.3 %. Therefore, FAP-C NPs hold great potential for targeted breast cancer therapy.

Single Cell RNA-Seq Identifies Cell Subpopulations Contributing to Idiopathic Pulmonary Fibrosis in Humans

The cell populations, particularly subpopulations, involved in the onset and progression of idiopathic pulmonary fibrosis (IPF) remain incompletely understood. This study employed single-cell RNA-seq to identify cell populations and subpopulations with significantly altered proportions in the lungs of patients with IPF. In IPF lungs, endothelial cell proportions were significantly increased, while alveolar epithelial cell proportions were markedly decreased. Among the three identified fibroblast subpopulations, the proportion of myofibroblasts was significantly increased, while the proportions of the other two fibroblast subtypes were reduced. Similarly, within the three macrophage subpopulations, the macrophage_SPP1 subpopulation, localised to fibroblastic foci, showed a significant increase in proportion, while the alveolar macrophage subpopulation was significantly reduced. Trajectory analysis revealed that fibroblasts in IPF lungs could differentiate into myofibroblasts, and alveolar macrophages could transition into the macrophage_SPP1 subpopulation. Among T-cell subpopulations, only the CD4 T_FOXP3 subpopulation exhibited a significant change, whereas all four B-cell subpopulations showed significant proportional shifts. These findings provide a comprehensive view of the cellular alterations contributing to IPF pathogenesis. Extensive interactions among various cell populations and subpopulations were identified. The proportions of various cell populations and subpopulations in IPF lungs, including endothelial cells, fibroblasts, macrophages and B cells, were significantly altered. Further in-depth investigation into the roles of cell subpopulations with significantly altered proportions in the onset and progression of IPF will provide valuable insights into the pathological mechanisms underlying the disease. This understanding could facilitate the development of novel therapeutic strategies and medications for IPF treatment.

Inhibition of peptidyl arginine deiminase-4 ameliorated pulmonary fibrosis via modulating M1/M2 polarisation of macrophages

Pulmonary fibrosis (PF) arises from dysregulated wound healing, leading to excessive extracellular matrix (ECM) deposition and impaired lung function. Macrophages exhibit high plasticity, polarizing to pro-inflammatory M1 during early inflammation and anti-inflammatory, fibrosis-inducing M2 during later stages of PF. Additionally, neutrophils and neutrophil extracellular traps (NETs) release mediated by peptidyl arginine deiminase (PAD-4), also play a key role in PF progression. PAD-4 inhibitor chloro-amidine (CLA) has shown anti-fibrotic effects in bleomycin (BLM) induced PF mouse model in our earlier study. Here, we have demonstrated that CLA also exhibited inhibition of macrophage polarisation in in-vitro in THP-1 monocytes and in-vivo in BLM induced PF. THP-1 monocytes were exposed to NETs isolated from phorbol 12-myristate-13-acetate (PMA) stimulated and PMA plus CLA treated differentiated HL-60 (dHL-60) cells. Monocytes exposed to stimulated NETs resulted in increased oxidative stress, disrupted mitochondrial membrane potential and increased M1 and M2 macrophage markers. These alterations were abrogated in THP-1 cells upon exposure to CLA treated NETs. Further, CLA treatment in BLM induced mice improved abnormal BALF, biochemical, and histological parameters in line with our previous findings. Additionally, CLA also reduced M1 and M2 markers time-dependently, as shown by immunofluorescence (IF), western blot, and RT-PCR analysis. CLA treatment led to decreased expression of PAD-4, M1-related pro-inflammatory cytokines and M2-related pro-fibrotic cytokines and mediators, as confirmed by western blot and ELISA analysis. Thus, it is established that inhibition of PAD-4 lead to mitigation of macrophage polarisation and a combined anti-fibrotic effect is achieved which can be explored further.

Potential mechanisms for chorioamniotic membrane rupture after subchorionic hematoma

BACKGROUND

Subchorionic hematoma is a risk factor for preterm prelabor rupture of membranes and preterm birth. A small proportion of persistent subchorionic hematoma leads to a chronic abruption-oligohydramnios sequence.

OBJECTIVE

To determine the mechanism by which subchorionic hematomas may damage chorioamniotic membranes.

STUDY DESIGN

1) The number and subtype of macrophages were determined by immunohistochemistry in chorioamniotic membranes from 8 subchorionic hematoma patients who delivered preterm (25.5 (24-32) weeks of gestation (median and range)) and 6 gestational age-matched control patients (25.5 (25-28) weeks of gestation (median and range)). Further, the thickness and fibrosis of the membranes were quantified. 2) We also developed an intrauterine hematoma model in pregnant mice, and the effects of hematoma on the amnion were analyzed by histology and immunofluorescence. 3) In vitro, primary human amnion mesenchymal cells were cocultured with M2-differentiated macrophages, and changes in mesenchymal cells were analyzed.

RESULTS

1) Subchorionic hematoma increased the number of iron-laden macrophages in the human amnion. These macrophages were CD206+, a marker of macrophages required for the maintenance of homeostasis, tissue remodeling, and metabolic adaptations. The collagen layer of the amnion tended to be thickened in patients with subchorionic hematoma. Interestingly, α-smooth muscle actin+ myofibroblasts were increased in the amnion mesenchymal layer in patients with subchorionic hematoma. Vimentin, a mesenchymal marker, was expressed in the epithelial layer of the hematoma amnion. Together, these findings indicate epithelial-mesenchymal transition in the amnion of membranes from pregnancies with subchorionic hematomas. 2) These findings in human amnion were confirmed in a mouse model of intrauterine hematoma. 3) Further, in vitro, coculture of human amnion mesenchymal cells with M2-differentiated human macrophages resulted in transformation of these cells into α-smooth muscle actin-expressing myofibroblasts via the TGF-β‒Smad3 pathway.

CONCLUSION

Subchorionic hematoma induces migration of macrophages to chorioamniotic membranes which activate the transition of amnion mesenchymal cells to myofibroblasts. These myofibroblasts may contribute to fibrosis of the amnion and damage chorioamniotic membranes.

NLRP3: a key regulator of skin wound healing and macrophage-fibroblast interactions in mice

Wound healing is a highly coordinated process driven by intricate molecular signaling and dynamic interactions between diverse cell types. Nod-like receptor pyrin domain-containing protein 3 (NLRP3) has been implicated in the regulation of inflammation and tissue repair; however, its specific role in skin wound healing remains unclear. This study highlights the pivotal role of NLRP3 in effective skin wound healing, as demonstrated by delayed wound closure and altered cellular and molecular responses in NLRP3-deficient (NLRP3-/-) mice. Histological analysis revealed impaired healing processes, accompanied by reduced expression of key inflammatory mediators, including interleukin-6 (IL-6), tumor necrosis factor-α (TNF-α), and prostaglandin E2 (PGE2). Deficiencies in apoptosis were evident through altered expression of cysteine-aspartic acid protease 3 (Caspase-3), P53, and B-cell lymphoma-2 (Bcl-2). Furthermore, critical growth factors such as vascular endothelial growth factor (VEGF), epidermal growth factor (EGF), and matrix metalloproteinase-9 (MMP-9) were significantly decreased at the excisional skin wound sites. Furthermore, using co-culture systems, we found that NLRP3 mediated the interaction between macrophages and myofibroblasts. Wild-type fibroblast-conditioned media (MFbCM) enhanced nitric oxide (NO), IL-6, and tumor necrosis factor-α (TNF-α) production in M1 macrophages and arginase activity, chitinase 3-like protein 1 (Ym1), and IL-10 expression in M2 macrophages, effects significantly diminished with NLRP3-/- MFbCM. Similarly, conditioned media from wild-type M1 or M2 macrophages promoted the expression of FGF-2, VEGF, and MMP-2 expression in myofibroblasts, which was attenuated when using NLRP3-/- macrophage-conditioned media. PGE2 levels were reduced in both NLRP3-/- macrophages and myofibroblasts. Supplementing NLRP3-/- conditioned media with PGE2 partially restored the impaired functions, suggesting that PGE2 acts as a downstream mediator of NLRP3-regulated macrophage-myofibroblast interactions. These findings indicate that NLRP3 is a key regulator of skin wound healing, facilitating macrophage-myofibroblast communication.