Mechanical and Physical Regulation of Fibroblast-Myofibroblast Transition: From Cellular Mechanoresponse to Tissue Pathology

Mechanotransduction in the Vocal Fold Microenvironment: A Narrative Review

PURPOSE

The vocal fold tissues undergo nearly continuous and repeated cycles of injury and repair throughout the course of an individual's lifetime. It is well established that certain individuals are at greater risk of lesion development based on personality and behavioral classification. However, these characteristics alone do not wholly predict or explain lesion development or severity. In this review, we discuss current knowledge of mechanotransduction proteins and their potential relevance to tissue homeostasis in the vocal folds.

METHOD

A review of literature surrounding mechanotransduction and tissue homeostasis as it relates to the vocal folds was conducted. Review of the literature included searches of PubMed, Google Scholar, and other various online peer-reviewed sources. Search terms pertained to mechanosensation, mechanotransduction, mechanically activated channels, mechanical cellular regulation, and other associated concepts and terms. Additional literature was identified through the reference lists of identified papers. Findings of this literature review were then applied to known physiology and pathophysiology of the vocal folds in order to speculate on the contribution of mechanically mediated mechanisms within the vocal fold.

DISCUSSION AND CONCLUSION

Because the vocal folds are such mechanically active structures, withstanding nearly constant external forces, there is strong support for the idea that mechanically sensitive molecular pathways within the vocal fold tissue play a major role in tissue homeostasis in the presence of these considerable forces. As such, mechanotransduction within the vocal fold should be considered and targeted in future biological studies of vocal fold physiology.

TNIK's emerging role in cancer, metabolism, and age-related diseases

Traf2- and Nck-interacting kinase (TNIK) has emerged as a key regulator of pathological metabolic signaling in several diseases and is a promising drug target. Originally studied for its role in cell migration and proliferation, TNIK possesses several newly identified functions that drive the pathogenesis of multiple diseases. Specifically, we evaluate TNIK's newfound roles in cancer, metabolic disorders, and neuronal function. We emphasize the implications of TNIK signaling in metabolic signaling and evaluate the translational potential of these discoveries. We also highlight how TNIK's role in many biological processes converges upon several hallmarks of aging. We conclude by discussing the therapeutic landscape of TNIK-targeting drugs and the recent success of clinical trials targeting TNIK.

Multiscale Control of Nanofiber-Composite Hydrogel for Complex 3D Cell Culture by Extracellular Matrix Composition and Nanofiber Alignment

In order to manipulate the complex behavior of cells in a 3-dimensional (3D) environment, it is important to provide the microenvironment that can accurately portray the complexity of highly anisotropic tissue structures. However, it is technically challenging to generate a complex microenvironment using conventional biomaterials that are mostly isotropic with limited bioactivity. In this study, the gelatin-hyaluronic acid hydrogel incorporated with aqueous-dispersible, short nanofibers capable of in situ alignment is developed to emulate the native heterogeneous extracellular matrix consisting of fibrous and non-fibrous components. The gelatin nanofibers containing magnetic nanoparticles, which could be aligned by external magnetic field, are dispersed and embedded in gelatin-hyaluronic acid hydrogel encapsulated with dermal fibroblasts. The aligned nanofibers via magnetic field could be safely integrated into the hydrogel, and the process could be repeated to generate larger 3D hydrogels with variable nanofiber alignments. The aligned nanofibers in the hydrogel can more effectively guide the anisotropic morphology (e.g., elongation) of dermal fibroblasts than random nanofibers, whereas myofibroblastic differentiation is more prominent in random nanofibers. At a given nanofiber configuration, the hydrogel composition having intermediate hyaluronic acid content induces myofibroblastic differentiation. These results indicate that modulating the degree of nanofiber alignment and the hyaluronic acid content of the hydrogel are crucial factors that critically influence the fibroblast phenotypes. The nanofiber-composite hydrogel capable of directional nanofiber alignment and tunable material composition can effectively induce a wide array of phenotypic plasticity in 3D cell culture.

Elucidating the interaction between stretch and stiffness using an agent-based spring network model of progressive pulmonary fibrosis

Pulmonary fibrosis is a deadly disease that involves the dysregulation of fibroblasts and myofibroblasts, which are mechanosensitive. Previous computational models have succeeded in modeling stiffness-mediated fibroblasts behaviors; however, these models have neglected to consider stretch-mediated behaviors, especially stretch-sensitive channels and the stretch-mediated release of latent TGF-β. Here, we develop and explore an agent-based model and spring network model hybrid that is capable of recapitulating both stiffness and stretch. Using the model, we evaluate the role of mechanical signaling in homeostasis and disease progression during self-healing and fibrosis, respectively. We develop the model such that there is a fibrotic threshold near which the network tends towards instability and fibrosis or below which the network tends to heal. The healing response is due to the stretch signal, whereas the fibrotic response occurs when the stiffness signal overpowers the stretch signal, creating a positive feedback loop. We also find that by changing the proportional weights of the stretch and stiffness signals, we observe heterogeneity in pathological network structure similar to that seen in human IPF tissue. The system also shows emergent behavior and bifurcations: whether the network will heal or turn fibrotic depends on the initial network organization of the damage, clearly demonstrating structure's pivotal role in healing or fibrosis of the overall network. In summary, these results strongly suggest that the mechanical signaling present in the lungs combined with network effects contribute to both homeostasis and disease progression.

Single-Cell Analyses Offer Insights into the Different Remodeling Programs of Arteries and Veins

Arteries and veins develop different types of occlusive diseases and respond differently to injury. The biological reasons for this discrepancy are not well understood, which is a limiting factor for the development of vein-targeted therapies. This study contrasts human peripheral arteries and veins at the single-cell level, with a focus on cell populations with remodeling potential. Upper arm arteries (brachial) and veins (basilic/cephalic) from 30 organ donors were compared using a combination of bulk and single-cell RNA sequencing, proteomics, flow cytometry, and histology. The cellular atlases of six arteries and veins demonstrated a 7.8× higher proportion of contractile smooth muscle cells (SMCs) in arteries and a trend toward more modulated SMCs. In contrast, veins showed a higher abundance of endothelial cells, pericytes, and macrophages, as well as an increasing trend in fibroblasts. Activated fibroblasts had similar proportions in both types of vessels but with significant differences in gene expression. Modulated SMCs and activated fibroblasts were characterized by the upregulation of MYH10, FN1, COL8A1, and ITGA10. Activated fibroblasts also expressed F2R, POSTN, and COMP and were confirmed by F2R/CD90 flow cytometry. Activated fibroblasts from veins were the top producers of collagens among all fibroblast populations from both types of vessels. Venous fibroblasts were also highly angiogenic, proinflammatory, and hyper-responders to reactive oxygen species. Differences in wall structure further explain the significant contribution of fibroblast populations to remodeling in veins. Fibroblasts are almost exclusively located outside the external elastic lamina in arteries, while widely distributed throughout the venous wall. In line with the above, ECM-targeted proteomics confirmed a higher abundance of fibrillar collagens in veins vs. more basement ECM components in arteries. The distinct cellular compositions and transcriptional programs of reparative populations in arteries and veins may explain differences in acute and chronic wall remodeling between vessels. This information may be relevant for the development of antistenotic therapies.

Tissue fibroblasts are versatile immune regulators: An evaluation of their impact on the aging process

Fibroblasts are abundant stromal cells which not only control the integrity of extracellular matrix (ECM) but also act as immune regulators. It is known that the structural cells within tissues can establish an organ-specific immunity expressing many immune-related genes and closely interact with immune cells. In fact, fibroblasts can modify their immune properties to display both pro-inflammatory and immunosuppressive activities in a context-dependent manner. After acute insults, fibroblasts promote tissue inflammation although they concurrently recruit immunosuppressive cells to enhance the resolution of inflammation. In chronic pathological states, tissue fibroblasts, especially senescent fibroblasts, can display many pro-inflammatory and immunosuppressive properties and stimulate the activities of different immunosuppressive cells. In return, immunosuppressive cells, such as M2 macrophages and myeloid-derived suppressor cells (MDSC), evoke an excessive conversion of fibroblasts into myofibroblasts, thus aggravating the severity of tissue fibrosis. Single-cell transcriptome studies on fibroblasts isolated from aged tissues have confirmed that tissue fibroblasts express many genes coding for cytokines, chemokines, and complement factors, whereas they lose some fibrogenic properties. The versatile immune properties of fibroblasts and their close cooperation with immune cells indicate that tissue fibroblasts have a crucial role in the aging process and age-related diseases.

A two-way street - cellular metabolism and myofibroblast contraction

Tissue fibrosis is characterised by the high-energy consumption associated with myofibroblast contraction. Although myofibroblast contraction relies on ATP production, the role of cellular metabolism in myofibroblast contraction has not yet been elucidated. Studies have so far only focused on myofibroblast contraction regulators, such as integrin receptors, TGF-β and their shared transcription factor YAP/TAZ, in a fibroblast-myofibroblast transition setting. Additionally, the influence of the regulators on metabolism and vice versa have been described in this context. However, this has so far not yet been connected to myofibroblast contraction. This review focuses on the known and unknown of how cellular metabolism influences the processes leading to myofibroblast contraction and vice versa. We elucidate the signalling cascades responsible for myofibroblast contraction by looking at FMT regulators, mechanical cues, biochemical signalling, ECM properties and how they can influence and be influenced by cellular metabolism. By reviewing the existing knowledge on the link between cellular metabolism and the regulation of myofibroblast contraction, we aim to pinpoint gaps of knowledge and eventually help identify potential research targets to identify strategies that would allow switching tissue fibrosis towards tissue regeneration.

Fibrosis-on-Chip: A Guide to Recapitulate the Essential Features of Fibrotic Disease

Fibrosis, which is primarily marked by excessive extracellular matrix (ECM) deposition, is a pathophysiological process associated with many disorders, which ultimately leads to organ dysfunction and poor patient outcomes. Despite the high prevalence of fibrosis, currently there exist few therapeutic options, and importantly, there is a paucity of in vitro models to accurately study fibrosis. This review discusses the multifaceted nature of fibrosis from the viewpoint of developing organ-on-chip (OoC) disease models, focusing on five key features: the ECM component, inflammation, mechanical cues, hypoxia, and vascularization. The potential of OoC technology is explored for better modeling these features in the context of studying fibrotic diseases and the interplay between various key features is emphasized. This paper reviews how organ-specific fibrotic diseases are modeled in OoC platforms, which elements are included in these existing models, and the avenues for novel research directions are highlighted. Finally, this review concludes with a perspective on how to address the current gap with respect to the inclusion of multiple features to yield more sophisticated and relevant models of fibrotic diseases in an OoC format.

Measuring integrin force loading rates using a two-step DNA tension sensor

Cells apply forces to extracellular matrix (ECM) ligands through transmembrane integrin receptors: an interaction which is intimately involved in cell motility, wound healing, cancer invasion and metastasis. These small (pN) forces exerted by cells have been studied by molecular tension fluorescence microscopy (MTFM), which utilizes a force-induced conformational change of a probe to detect mechanical events. MTFM has revealed the force magnitude for integrins receptors in a variety of cell models including primary cells. However, force dynamics and specifically the force loading rate (LR) have important implications in receptor signaling and adhesion formation and remain poorly characterized. Here, we develop a LR probe which is comprised of an engineered DNA structures that undergoes two mechanical transitions at distinct force thresholds: a low force threshold at 4.7 pN corresponding to hairpin unfolding and a high force threshold at 56 pN triggered through duplex shearing. These transitions yield distinct fluorescence signatures observed through single-molecule fluorescence microscopy in live-cells. Automated analysis of tens of thousands of events from 8 cells showed that the bond lifetime of integrins that engage their ligands and transmit a force >4.7 pN decays exponentially with a τ of 45.6 sec. A small subset of these events (<10%) mature in magnitude to >56pN with a median loading rate of 1.3 pNs-1 with these mechanical ramp events localizing at the periphery of the cell-substrate junction. Importantly, the LR probe design is modular and can be adapted to measure force ramp rates for a broad range of mechanoreceptors and cell models, thus aiding in the study of mechanotransduction.

Endothelial cells regulate alveolar morphogenesis by constructing basement membranes acting as a scaffold for myofibroblasts

Alveologenesis is a spatially coordinated morphogenetic event, during which alveolar myofibroblasts surround the terminal sacs constructed by epithelial cells and endothelial cells (ECs), then contract to form secondary septa to generate alveoli in the lungs. Recent studies have demonstrated the important role of alveolar ECs in this morphogenetic event. However, the mechanisms underlying EC-mediated alveologenesis remain unknown. Herein, we show that ECs regulate alveologenesis by constructing basement membranes (BMs) acting as a scaffold for myofibroblasts to induce septa formation through activating mechanical signaling. Rap1, a small GTPase of the Ras superfamily, is known to stimulate integrin-mediated cell adhesions. EC-specific Rap1-deficient (Rap1iECKO) mice exhibit impaired septa formation and hypo-alveolarization due to the decreased mechanical signaling in myofibroblasts. In Rap1iECKO mice, ECs fail to stimulate integrin β1 to recruit Collagen type IV (Col-4) into BMs required for myofibroblast-mediated septa formation. Consistently, EC-specific integrin β1-deficient mice show hypo-alveolarization, defective mechanical signaling in myofibroblasts, and disorganized BMs. These data demonstrate that alveolar ECs promote integrin β1-mediated Col-4 recruitment in a Rap1-dependent manner, thereby constructing BMs acting as a scaffold for myofibroblasts to induce mechanical signal-mediated alveologenesis. Thus, this study unveils a mechanism of organ morphogenesis mediated by ECs through intrinsic functions.

The Effect of Substrate Properties on Cellular Behavior and Nanoparticle Uptake in Human Fibroblasts and Epithelial Cells

The delivery of nanomedicines into cells holds enormous therapeutic potential; however little is known regarding how the extracellular matrix (ECM) can influence cell-nanoparticle (NP) interactions. Changes in ECM organization and composition occur in several pathophysiological states, including fibrosis and tumorigenesis, and may contribute to disease progression. We show that the physical characteristics of cellular substrates, that more closely resemble the ECM in vivo, can influence cell behavior and the subsequent uptake of NPs. Electrospinning was used to create two different substrates made of soft polyurethane (PU) with aligned and non-aligned nanofibers to recapitulate the ECM in two different states. To investigate the impact of cell-substrate interaction, A549 lung epithelial cells and MRC-5 lung fibroblasts were cultured on soft PU membranes with different alignments and compared against stiff tissue culture plastic (TCP)/glass. Both cell types could attach and grow on both PU membranes with no signs of cytotoxicity but with increased cytokine release compared with cells on the TCP. The uptake of silica NPs increased more than three-fold in fibroblasts but not in epithelial cells cultured on both membranes. This study demonstrates that cell-matrix interaction is substrate and cell-type dependent and highlights the importance of considering the ECM and tissue mechanical properties when designing NPs for effective cell targeting and treatment.

AMPK signaling inhibits the differentiation of myofibroblasts: impact on age-related tissue fibrosis and degeneration

Disruption of the extracellular matrix (ECM) and an accumulation of fibrotic lesions within tissues are two of the distinctive hallmarks of the aging process. Tissue fibroblasts are mesenchymal cells which display an impressive plasticity in the regulation of ECM integrity and thus on tissue homeostasis. Single-cell transcriptome studies have revealed that tissue fibroblasts exhibit a remarkable heterogeneity with aging and in age-related diseases. Excessive stress and inflammatory insults induce the differentiation of fibroblasts into myofibroblasts which are fusiform contractile cells and abundantly secrete the components of the ECM and proteolytic enzymes as well as many inflammatory mediators. Detrimental stresses can also induce the transdifferentiation of certain mesenchymal and myeloid cells into myofibroblasts. Interestingly, many age-related stresses, such as oxidative and endoplasmic reticulum stresses, ECM stiffness, inflammatory mediators, telomere shortening, and several alarmins from damaged cells are potent inducers of myofibroblast differentiation. Intriguingly, there is convincing evidence that the signaling pathways stimulated by the AMP-activated protein kinase (AMPK) are potent inhibitors of myofibroblast differentiation and accordingly AMPK signaling reduces fibrotic lesions within tissues, e.g., in age-related cardiac and pulmonary fibrosis. AMPK signaling is not only an important regulator of energy metabolism but it is also able to control cell fate determination and many functions of the immune system. It is known that AMPK signaling can delay the aging process via an integrated signaling network. AMPK signaling inhibits myofibroblast differentiation, e.g., by suppressing signaling through the TGF-β, NF-κB, STAT3, and YAP/TAZ pathways. It seems that AMPK signaling can alleviate age-related tissue fibrosis and degeneration by inhibiting the differentiation of myofibroblasts.

On-Demand Sequential Release of Dual Drug from pH-Responsive Electrospun Janus Nanofiber Membranes toward Wound Healing and Infection Control

Drugs against bacteria and abnormal cells, such as antibiotics and anticancer drugs, may save human lives. However, drug resistance is becoming more common in the clinical world. Nowadays, a synergistic action of multiple bioactive compounds and their combination with smart nanoplatforms has been considered an alternative therapeutic strategy to fight drug resistance in multidrug-resistant cancers and microorganisms. The present study reports a one-step fabrication of innovative pH-responsive Janus nanofibers loaded with two active compounds, each in separate polymer compartments for synergistic combination therapy. By dissolving one of the compartments from the nanofibers, we could clearly demonstrate a highly yielded anisotropic Janus structure with two faces by scanning electron microscopy (SEM) analysis. To better understand the distinctive attributes of Janus nanofibers, several analytical methods, such as X-ray diffraction (XRD), FTIR spectroscopy, and contact angle goniometry, were utilized to examine and compare them to those of monolithic nanofibers. Furthermore, a drug release test was conducted in pH 7.4 and 6.0 media since the properties of Janus nanofibers correlate significantly with different environmental pH levels. This resulted in the on-demand sequential codelivery of octenidine (OCT) and curcumin (CUR) to the corresponding pH stimulus. Accordingly, the antibacterial properties of Janus fibers against Escherichia coli and Staphylococcus aureus, tested in a suspension test, were pH-dependent, i.e., greater in pH 6 due to the synergistic action of two active compounds, and Eudragit E100 (EE), and highly satisfactory. The biocompatibility of the Janus fibers was confirmed in selected tests.

Multifunctional carbon dots originated from waste garlic peel for rapid sensing of heavy metals and fluorescent imaging of 2D and 3D spheroids cultured fibroblast cells

Here, we prepared sulfur and nitrogen self-doped carbon dots derived from garlic peel extract (GPSNCDs) using a hydrothermal method. The as-synthesized GPSNCDs were confirmed using Fourier-transform infrared spectroscopy, X-ray diffraction, X-ray photoelectron spectroscopy, and transmission electron microscopy. The analytical techniques indicate that the resulting GPSNCDs exhibit distinct emissive carbon-core with functionalities (owing to various ligands in the GPSNCDs). These functionalities are responsible for excellent hydrophilic and optical properties, including excitation-dependent emission and anti-photobleaching. Fluorescence intensities of GPSNCDs were quenched in the existence of Mn2+ and Fe3+ ions. This indicates that the GPSNCDs were sensitive to Fe3+ and Mn2+ ions with a limited range from 5 to 50 µM and showed lower recognition at ∼0.75 and 0.95 µM, respectively. In addition, the sensing results were generated in a short time (20 s). The cytotoxicity of GPSNCDs was tested to demonstrate that they are sufficiently safe to use for cellular imaging. The novel fluorescent GPSNCDs-based sensor can be used as a high-performance sensor for environmental monitoring. Further, GPSNCDs showed greater biocompatibility with normal fibroblast cells, and In Vitro fluorescent imaging of GPSNCDs revealed strong fluorescence signals in the two-dimensional (2D) and three-dimensional (3D) spheroids cultured fibroblast cells. The properties mentioned above demonstrate that the GPSNCDs can be applied to imaging normal cells without further modifications.

Human organoids-on-chips for biomedical research and applications

Human organoids-on-chips (OrgOCs) are the synergism of human organoids (HOs) technology and microfluidic organs-on-chips (OOCs). OOCs can mimic extrinsic characteristics of organs, such as environmental clues of living tissue, while HOs are more amenable to biological analysis and genetic manipulation. By spatial cooperation, OrgOCs served as 3D organotypic living models allowing them to recapitulate critical tissue-specific properties and forecast human responses and outcomes. It represents a giant leap forward from the regular 2D cell monolayers and animal models in the improved human ecological niche modeling. In recent years, OrgOCs have offered potential promises for clinical studies and advanced the preclinical-to-clinical translation in medical and industrial fields. In this review, we highlight the cutting-edge achievements in OrgOCs, introduce the key features of OrgOCs architectures, and share the revolutionary applications in basic biology, disease modeling, preclinical assay and precision medicine. Furthermore, we discuss how to combine a wide range of disciplines with OrgOCs and accelerate translational applications, as well as the challenges and opportunities of OrgOCs in biomedical research and applications.

A Review of Genes Involved in Wound Healing

Background

Gene therapy holds immense potential in the field of wound healing. However, we still do not recognize this procedure well enough to give oversight effectively to improve healing processes. A wide range of information has been achieved from the database for gene expression profiling by clinical trials, So we performed this study to gain a better understanding of the mechanisms behind wound healing and how it could be utilized to develop new therapies and treatments.

Methods

In this study, we have been focusing on wound-healing genes, conducting a thorough review to explore the various genes and pathways involved in this process. For this purpose, a total of 320 articles were collected. All experimental studies, systematic or narrative reviews, studies and clinical trials included in this paper were searched on PubMed, Medline, Embase, Science Direct, and Scopus databases in English using the following terms: Wound Healing, wound regeneration, Gene Transfer, and Gene Therapy were used to search the mentioned databases. Unfortunately, we didn't find a large sample cohort study on this topic. A total amount of 330 articles were collected based on the guidelines of the PRISMA method. Both inclusion and exclusion criteria were settled.

Results

During the last decade, different models of gene delivery have been introduced, which include viral transfection and Non-viral techniques. In this regard, TIMP-2 protein and VEGF mutants such as VEGF165, CARP, and HIF-1 are the genes that accelerate the rate of tissue repair.

Conclusion

The process of wound healing is mainly related to the change of expression of genes that have a role in the parts of inflammation and repair. In our study, some of the most suitable genes involved in the wound-healing process are mentioned.

Models for Implant-Induced Capsular Contracture Post Breast Cancer Surgery

Capsular contracture is a painful deformation of scar-tissue that may form around an implant in post-breast cancer reconstruction or cosmetic surgery. Inflammation due to surgical trauma or contamination in the tissue around the implant could account for recruitment of immune cells, and transdifferentiation of resident fibroblasts into cells that deposit abnormally thick collagen. Here we examine this hypothesis using a mathematical model for interacting macrophages, fibroblasts, myofibroblasts, and collagen. Our model demonstrates that cellular response can, together with inflammatory cell recruitment, account for prognoses.

Long-term effects of vaginal surgery and endogenous ovarian hormones on the vagina and bladder

Background

Surgery is a common treatment for pelvic organ prolapse (POP); however, risk of recurrence and reoperation is high, resulting in a negative impact on quality of life and sexual function.

Aim

To examine the long-term effects of POP surgery and endogenous circulating ovarian hormones on the vagina and bladder.

Methods

Our animal model simulated surgical injury of the vagina and bladder during POP surgery. Female Rowett nude rats were divided into 4 groups: intact control (IC), vaginal surgery only (V), ovariectomy only (O), and ovariectomy + vaginal surgery (OV). Rats were euthanized 10 weeks postsurgery. Proximal vagina and bladder dome/trigone underwent (1) organ bath myography to assess smooth muscle contractility; (2) real-time quantitative polymerase chain reaction to quantify mRNA expression of elastin, collagen I and III, and PGP9.5 (protein gene product 9.5); (3) enzyme-linked immunosorbent assay for protein quantification of elastin and collagen I and III; and (4) hematoxylin-eosin/immunohistochemistry staining.

Outcomes

The primary outcome was tissue contractility as measured by organ bath myography. Secondary outcomes included gene and protein expression of collagen I and III and elastin.

Results

O and OV showed reduced vaginal wall contractility vs IC and V (P < .002). Bladder dome and trigone displayed different contractile patterns, with significant differences between O and OV (P < .05), suggesting a negative effect from surgery rather than ovariectomy. OV demonstrated consistent reductions in contractility and elastin/collagen protein expression for the vagina and bladder vs IC. V had similar contractility and increased collagen I expression vs IC, suggesting a protective effect of ovarian hormones. Vaginal epithelium thinning was confirmed in the ovariectomized groups (P = .001), although there was no statistical significance in muscularis thinning with surgery or ovariectomy. O, V, and OV showed significant downregulation of PGP9.5 mRNA expression vs IC.

Clinical Translation

These data allow researchers to gain insights into the long-term effects of surgery and deprivation of ovarian hormones. Future studies can use this animal model to investigate other mechanisms that may affect long-term tissue changes due to surgical intervention.

Strengths and Limitations

Major strengths are long-term data on the effects of POP surgery and development of an animal model for future studies. However, the animal model limits our ability to extrapolate to humans, where tissue healing is modulated by many factors.

Conclusion

Our animal model provides evidence that ovarian hormone deprivation and POP surgery result in negative long-term effects on tissue function and extracellular matrix.

Fibroblast activation protein imaging in atrial fibrillation: a proof-of-concept study

BACKGROUND

To evaluate the feasibility of using radiolabeled fibroblast activation protein inhibitor (FAPI) PET/CT imaging to assess activated fibroblasts in the atria of individuals with AF and to identify factors contributing to enhanced atrial activity.

METHODS

We constructed left atrial appendage (LAA) pacing beagle dog AF models (n = 5) and conducted 18F-FAPI PET/CT imaging at baseline and eight weeks after pacing. Right atrial (RA) specimens were collected from these models. Additionally, 28 AF patients and ten age- and sex-matched healthy volunteers underwent 18F-FAPI PET/CT imaging.

RESULTS

RA of AF beagles showed increased 18F-FAPI uptake. Among AF patients, 18 out of 28 (64.3%) exhibited enhanced atrial FAPI activity. No atrial 18F-FAPI uptake was observed in the sham beagle and healthy volunteers. In animal RA specimens, 18F-FAPI activity correlated positively with FAP mRNA (r = .98, P = .002) and protein (r = .82, P = .03) levels, as well as collagen I mRNA expression (r = .85, P = .02). B-type natriuretic peptide levels were associated with atrial 18F-FAPI activity (OR = 3.01, P = .046).

CONCLUSION

This proof-of-concept study suggests that 18F-FAPI PET/CT imaging may be a feasible method for evaluating activated fibroblasts in the atria of AF patients.

Helicobacter pylori-activated fibroblasts as a silent partner in gastric cancer development

The discovery of Helicobacter pylori (Hp) infection of gastric mucosa leading to active chronic gastritis, gastroduodenal ulcers, and MALT lymphoma laid the groundwork for understanding of the general relationship between chronic infection, inflammation, and cancer. Nevertheless, this sequence of events is still far from full understanding with new players and mediators being constantly identified. Originally, the Hp virulence factors affecting mainly gastric epithelium were proposed to contribute considerably to gastric inflammation, ulceration, and cancer. Furthermore, it has been shown that Hp possesses the ability to penetrate the mucus layer and directly interact with stroma components including fibroblasts and myofibroblasts. These cells, which are the source of biophysical and biochemical signals providing the proper balance between cell proliferation and differentiation within gastric epithelial stem cell compartment, when exposed to Hp, can convert into cancer-associated fibroblast (CAF) phenotype. The crosstalk between fibroblasts and myofibroblasts with gastric epithelial cells including stem/progenitor cell niche involves several pathways mediated by non-coding RNAs, Wnt, BMP, TGF-β, and Notch signaling ligands. The current review concentrates on the consequences of Hp-induced increase in gastric fibroblast and myofibroblast number, and their activation towards CAFs with the emphasis to the altered communication between mesenchymal and epithelial cell compartment, which may lead to inflammation, epithelial stem cell overproliferation, disturbed differentiation, and gradual gastric cancer development. Thus, Hp-activated fibroblasts may constitute the target for anti-cancer treatment and, importantly, for the pharmacotherapies diminishing their activation particularly at the early stages of Hp infection.

Investigating the Impact of Mechanical Properties and Cell-Collagen Interaction on NIH3T3 Function: A Comparative Study on Different Substrates and Culture Environments

This study investigates the intricate dynamics of matrix stiffness, substrate composition, and cell-cell interactions and elucidates their cumulative effects on fibroblast behavior in different culture contexts. Three primary substrate types were examined: non-coated, collagen-coated, and collagen hydrogel, within both two-dimensional (2D) monolayer and three-dimensional (3D) spheroid cultures. The research provides several key insights. First, 3D spheroid culture, which promotes robust cell-cell interactions, emerges as a critical factor in maintaining fibroblast functionality. Second, substrate stiffness significantly influences results, with the soft collagen hydrogel showing superior support for fibroblast function. Notably, fibroblasts cultured on collagen hydrogel in 2D exhibit comparable functionality to those in 3D, highlighting the importance of substrate mechanical properties. Third, surface composition, as exemplified by collagen coating, showed a limited effect compared to the other factors studied. These findings provide a basis for innovative applications in regenerative medicine, tissue engineering, and drug testing models, and offer valuable insights into harnessing the potential of fibroblasts and advancing biomedical sciences.

Identifying characteristics of dermal fibroblasts in skin homeostasis and disease

Heterogeneous dermal fibroblasts are the main components that constitute the dermis. Distinct fibroblast subgroups show specific characteristics and functional plasticity that determine dermal structure during skin development and wound healing. Although researchers have described the roles of fibroblast subsets, this is not completely understood. We review recent evidence supporting understanding about the heterogeneity of fibroblasts. We summarize the origins and the identified profiles of fibroblast subpopulations. The characteristics of fibroblast subpopulations in both healthy and diseased states are highlighted, and the potential of subpopulations to be involved in wound healing in different ways was discussed. Additionally, we review the plasticity of subpopulations and the underlying signalling mechanisms. This review may provide greater insights into potential novel therapeutic targets and tissue regeneration strategies for the future.

A two-scale numerical study on the mechanobiology of abdominal aortic aneurysms

Abdominal aortic aneurysms (AAAs) are a serious condition whose pathophysiology is related to phenomena occurring at different length scales. To gain a better understanding of the disease, this work presents a multi-scale computational study that correlates AAA progression with microstructural and mechanical alterations in the tissue. Macro-scale geometries of a healthy aorta and idealized aneurysms with increasing diameter are developed on the basis of existing experimental data and subjected to physiological boundary conditions. Subsequently, microscopic representative volume elements of the abluminal side of each macro-model are employed to analyse the local kinematics at the cellular scale. The results suggest that the formation of the aneurysm disrupts the micromechanics of healthy tissue, which could trigger collagen growth and remodelling by mechanosensing cells. The resulting changes to the macro-mechanics and microstructure of the tissue seem to establish a new homeostatic state at the cellular scale, at least for the diameter range investigated.

Role of oncostatin-M in ECM remodeling and plaque vulnerability

Atherosclerosis is a multifactorial inflammatory disease characterized by the development of plaque formation leading to occlusion of the vessel and hypoxia of the tissue supplied by the vessel. Chronic inflammation and altered collagen expression render stable plaque to unstable and increase plaque vulnerability. Thinned and weakened fibrous cap results in plaque rupture and formation of thrombosis and emboli formation leading to acute ischemic events such as stroke and myocardial infarction. Inflammatory mediators including TREM-1, TLRs, MMPs, and immune cells play a critical role in plaque vulnerability. Among the other inflammatory mediators, oncostatin-M (OSM), a pro-inflammatory cytokine, play an important role in the development and progression of atherosclerosis, however, the role of OSM in plaque vulnerability and extracellular matrix remodeling (ECM) is not well understood and studied. Since ECM remodeling plays an important role in atherosclerosis and plaque vulnerability, a detailed investigation on the role of OSM in ECM remodeling and plaque vulnerability is critical. This is important because the role of OSM has been discussed in the context of proliferation of vascular smooth muscle cells and regulation of cytokine expression but the role of OSM is scarcely discussed in relation to ECM remodeling and plaque vulnerability. This review focuses on critically discussing the role of OSM in ECM remodeling and plaque vulnerability.

Mesenchymal stem cell-derived secretomes-enriched alginate/ extracellular matrix hydrogel patch accelerates skin wound healing

BACKGROUND

The secretomes of mesenchymal stem cells (MSCs) have great therapeutic potential and thereby their efficient delivery into the target site is of particular interest. Here, we propose a new strategy of hMSCs-derived secretomes delivery for advanced wound healing upon harnessing the working principle of extracellular matrix (ECM)-growth factors interaction in vivo.

METHODS

We prepared an alginate hydrogel based wound patch, where it contains both human MSC-derived secretomes and ECM. The ECM was obtained from the decellularization of in vitro cultured human lung fibroblasts. The alginate solution was blended with ECM suspension, crosslinked, air-dried, then rehydrated with the secretomes contained in the concentrated conditioned media (CCM) as a highly saturated form of conditioned media (CM). We tested four different groups, with or without the ECM to investigate not only the role of ECM but the therapeutic effect of secretomes.

RESULTS

The secretomes reserved many, diverse bioactive factors, such as VEGF, HGF, IGFBPs, IL-6, and IL-8. Alginate/ECM/CCM (AEC) patch could hold significantly larger amount of secretomes and release them longer than the other groups. Our AEC patch was the most effective in stimulating not only cell migration and proliferation but the collagen synthesis of dermal fibroblasts in vitro. Moreover, the AEC patch-treated full-thickness skin wounds disclosed significantly better wound healing indications: cell recruitment, neovascularization, epidermis thickness, keratinocyte migration, and mature collagen deposition, as assessed via histology (H&E, Herovici staining) and immunofluorescence, respectively. In particular, our AEC patch enabled a phenotype shift of myofibroblast into fibroblast over time and led to mature blood vessel formation at 14 day.

CONCLUSIONS

We believe that ECM certainly contributed to generate a secretomes-enriched milieu via ECM-secretomes interactions and thereby such secretomes could be delivered more efficiently, exerting significant therapeutic impact either individually or collectively during wound healing process.

Time-sequential fibroblast-to-myofibroblast transition in elastin-variable 3D hydrogel environments by collagen networks

BACKGROUND

Fibrosis plays an important role in both normal physiological and pathological phenomena as fibroblasts differentiate to myofibroblasts. The activation of fibroblasts is determined through interactions with the surrounding extracellular matrix (ECM). However, how this fibroblast-to-myofibroblast transition (FMT) is regulated and affected by elastin concentration in a three-dimensional (3D) microenvironment has not been investigated.

METHODS

We developed an insoluble elastin-gradient 3D hydrogel system for long-lasting cell culture and studied the molecular mechanisms of the FMT in embedded cells by nanoflow LC-MS/MS analysis along with validation through real-time PCR and immunofluorescence staining.

RESULTS

By optimizing pH and temperature, four 3D hydrogels containing fibroblasts were successfully fabricated having elastin concentrations of 0, 20, 50, and 80% in collagen. At the low elastin level (20%), fibroblast proliferation was significantly increased compared to others, and in particular, the FMT was clearly observed in this condition. Moreover, through mass spectrometry of the hydrogel environment, it was confirmed that differentiation proceeded in two stages. In the early stage, calcium-dependent proteins including calmodulin and S100A4 were highly associated. On the other hand, in the late stage after several passages of cells, distinct markers of myofibroblasts were presented such as morphological changes, increased production of ECM, and increased α-SMA expression. We also demonstrated that the low level of elastin concentration induced some cancer-associated fibroblast (CAF) markers, including PDGFR-β, and fibrosis-related disease markers, including THY-1.

CONCLUSION

Using our developed 3D elastin-gradient hydrogel system, we evaluated the effect of different elastin concentrations on the FMT. The FMT was induced even at a low concentration of elastin with increasing CAF level via calcium signaling. With this system, we were able to analyze varying protein expressions in the overall FMT process over several cellular passages. Our results suggest that the elastin-gradient system employing nonlinear optics imaging provides a good platform to study activated fibroblasts interacting with the microenvironment, where the ECM plays a pivotal role.

Effect of Porous Substrate Topographies on Cell Dynamics: A Computational Study

Controlling cell-substrate interactions via the microstructural characteristics of biomaterials offers an advantageous path for modulating cell dynamics, mechanosensing, and migration, as well as for designing immune-modulating implants, all without the drawbacks of chemical-based triggers. Specifically, recent in vivo studies have suggested that a porous implant's microscale curvature landscape can significantly impact cell behavior and ultimately the immune response. To investigate such cell-substrate interactions, we utilized a 3D computational model incorporating the minimum necessary physics of cell migration and cell-substrate interactions needed to replicate known in vitro behaviors. This model specifically incorporates the effect of membrane tension, which was found to be necessary to replicate in vitro cell behavior on curved surfaces. Our simulated substrates represent two classes of porous materials recently used in implant studies, which have markedly different microscale curvature distributions and pore geometries. We found distinct differences between the overall migration behaviors, shapes, and actin polymerization dynamics of cells interacting with the two substrates. These differences were correlated to the shape energy of the cells as they interacted with the porous substrates, in effect interpreting substrate topography as an energetic landscape interrogated by cells. Our results demonstrate that microscale curvature directly influences cell shape and migration and, therefore, is likely to influence cell behavior. This supports further investigation of the relationship between the surface topography of implanted materials and the characteristic immune response, a complete understanding of which would broadly advance principles of biomaterial design.

3D in vitro hydrogel models to study the human lung extracellular matrix and fibroblast function

The pulmonary extracellular matrix (ECM) is a macromolecular structure that provides mechanical support, stability and elastic recoil for different pulmonary cells including the lung fibroblasts. The ECM plays an important role in lung development, remodeling, repair, and the maintenance of tissue homeostasis. Biomechanical and biochemical signals produced by the ECM regulate the phenotype and function of various cells including fibroblasts in the lungs. Fibroblasts are important lung structural cells responsible for the production and repair of different ECM proteins (e.g., collagen and fibronectin). During lung injury and in chronic lung diseases such as asthma, idiopathic pulmonary fibrosis (IPF) and chronic obstructive pulmonary disease (COPD), an abnormal feedback between fibroblasts and the altered ECM disrupts tissue homeostasis and leads to a vicious cycle of fibrotic changes resulting in tissue remodeling. In line with this, using 3D hydrogel culture models with embedded lung fibroblasts have enabled the assessment of the various mechanisms involved in driving defective (fibrotic) fibroblast function in the lung's 3D ECM environment. In this review, we provide a summary of various studies that used these 3D hydrogel models to assess the regulation of the ECM on lung fibroblast phenotype and function in altered lung ECM homeostasis in health and in chronic respiratory disease.

Angiogenin as a Possible Mediator of Macrophage-Mediated Regulation of Fibroblast Functions

We studied angiogenin production by human macrophages and evaluated the role of this factor in the macrophage-mediated regulation of fibroblasts. All macrophage subtypes, and especially the efferocytosis-polarized macrophages, M2(LS), actively produced angiogenin. Exogenous recombinant angiogenin dose-dependently enhanced the proliferation and differentiation of dermal fibroblasts. The addition of the angiogenin inhibitor to fibroblasts cultures suppressed the stimulating effect of exogenous angiogenin or M2(LS) conditioned media. These findings indicate the involvement of angiogenin in the macrophage-mediated paracrine regulation of skin fibroblasts.

An Open-Label, Uncontrolled, Single-Arm Clinical Trial of Tofacitinib, an Oral JAK1 and JAK3 Kinase Inhibitor, in Chinese Patients with Keloid

BACKGROUND

The keloid treatment is still a thorny and complicated clinical problem, especially in multiple keloids induced by wound, severe burn, ethnic background or cultural behaviors, or unexplained skin healing. Mainstream treatments have limited efficacy in treating multiple keloids. As no oral treatment with painlessness and convenience is available, oral treatment strategies should be formulated.

OBJECTIVES

This study aimed to investigate the efficacy and therapeutic mechanism of oral tofacitinib in keloid patients.

METHODS

We recruited the 7 patients with keloid scars and prescribed 5 mg of tofacitinib twice a day orally with a maximum follow-up of 12 weeks. The Patient and Observer Scar Assessment Scale (POSAS), the Vancouver scar scale (VSS), ANTERA 3D camera, and the DUB Skin Scanner 75 were used to assess the characteristics of the lesion. Immunohistochemistry was performed to evaluate collagen synthesis, proliferation, and relative molecular pathways. Moreover, the effects of tofacitinib were assessed on keloid fibroblast in vitro.

RESULTS

After 12 weeks of oral tofacitinib, significant improvement in POSAS, VSS, and Dermatology Life Quality Index (DLQI) scores was observed (p < 0.05). The volume, lesion height, and dermis thickness of the keloid decreased (p < 0.05). Moreover, significant decreases in the expression of collagen I, Ki67, p-STAT 3, and p-SMAD2 were observed after 12 weeks of administration. In vitro experiments suggested that tofacitinib treatment inhibits fibroblast proliferation and collagen I synthesis via suppression of STAT3 and SMAD2 pathway.

CONCLUSION

Tofacitinib, a new candidate oral drug for keloid, could reduce keloid lesion volume by inhibiting collagen synthesis and inhibiting fibroblast proliferation, and alleviate itch and pain to obtain a better life quality.

Inhibitory Effects of Epithelial Cells on Fibrosis Mechanics of Microtissue and Their Spatiotemporal Dependence on the Epithelial-Fibroblast Interaction

Cell-generated contraction force is the primary physical drive for fibrotic densification of biological tissues. Previous studies using two-dimensional culture models have shown that epithelial cells inhibit the myofibroblast-derived contraction force via the regulation of the fibroblast/myofibroblast transition (FMT). However, it remains unclear how epithelial cells interact with fibroblasts and myofibroblasts to determine the mechanical consequences and spatiotemporal regulation of fibrosis development. In this study, we established a three-dimensional microtissue model using an NIH/3T3 fibroblast-laden collagen hydrogel, incorporated with a microstring-based force sensor, to assess fibrosis mechanics. When Madin-Darby canine kidney epithelial cells were cocultured on the microtissue's surface, the densification, stiffness, and contraction force of the microtissue greatly decreased compared to the monocultured microtissue without epithelial cells. The key fibrotic features, such as enhanced protein expression of α-smooth muscle actin, fibronectin, and collagen indicating FMT and matrix deposition, respectively, were also significantly reduced. The antifibrotic effects of epithelial cells on the microtissue were dependent on the intercellular signaling molecule prostaglandin E2 (PGE2) with an effective concentration of 10 μM and their proximity to the fibroblasts, indicating paracrine cellular signaling between the two types of cells during tissue fibrosis. The effect of PGE2 on microtissue contraction was also dependent on the time point when PGE2 was delivered or blocked, suggesting that the presence of epithelial cells at an early stage is critical for preventing or treating advanced fibrosis. Taken together, this study provides insights into the spatiotemporal regulation of mechanical properties of fibrosis by epithelial cells, and the cocultured microtissue model incorporated with a real-time and sensitive force sensor will be a suitable system for evaluating fibrosis and drug screening.

Synergistic Modulation of a Tunable Microenvironment to Fabricate a Liver Fibrosis Chip for Drug Testing

Liver fibrosis is a progressive physiological change that occurs after liver injury and seriously endangers human health. The lack of reliable and physiologically relevant pathological models of liver fibrosis leads to a longer drug development period and sizeable economic investment. The fabrication of a biomimetic liver-on-a-chip is significant for liver disease treatment and drug development. Here, a sandwich chip with a microwell array structure in its bottom layer was fabricated to simulate the Disse space structure of hepatic sinusoids in vitro. By synergistic modulation of the cross-linking degree of gelatin-methacryloyl (GelMA) hydrogels and the induction of transforming growth factor-beta (TGF-β), the early and late stages of liver fibrosis were designed in the chip. Owing to its three-dimensional-mixed-culture strategy, it was possible to construct a liver sinusoid model in vitro to allow for faithful physiological emulation. The model was further subjected to drug treatment, and it presented a significant difference in treatment response in early and late fibrosis progression. Our system provides a unique method for emulating liver function through a vitro liver fibrosis-on-a-chip, potentially paving the way for investigating human liver fibrosis and related drug development.

Fucoidan from Saccharina japonica Alleviates Hyperuricemia-Induced Renal Fibrosis through Inhibiting the JAK2/STAT3 Signaling Pathway

Fucoidan is a native sulfated polysaccharide mainly isolated from brown seaweed, with diverse pharmacological activities, such as anti-inflammatory and antifibrosis. Hyperuricemia (HUA) is a common metabolic disease worldwide and mainly causes hyperuricemic nephropathy, including chronic kidney disease and end-stage renal fibrosis. The present study investigated the protective function of fucoidan in renal fibrosis and its pharmacological mechanism. The renal fibrotic model was established with the administration of potassium oxonate for 10 weeks. The protein levels of related factors were assessed in HUA mice by an enzyme-linked immunosorbent assay (ELISA) and western blotting. The results showed that fucoidan significantly reduced the levels of serum uric acid, blood urea nitrogen (BUN), α-smooth muscle actin (α-SMA), and collagen I, and improved kidney pathological changes. Furthermore, renal fibrosis had been remarkably elevated through the inhibition of the epithelial-to-mesenchymal transition (EMT) progression after fucoidan intervention, suppressing the Janus kinase 2 (JAK2) signal transducer and activator of transcription protein 3 (STAT3) signaling pathway activation. Together, this study provides experimental evidence that fucoidan may protect against hyperuricemia-induced renal fibrosis via downregulation of the JAK2/STAT3 signaling pathway.

Distinct Organotypic Platforms Modulate Rainbow Trout (Oncorhynchus mykiss) Intestinal Cell Differentiation In Vitro

In vitro organotypic cell-based intestinal platforms, able to faithfully recapitulate the complex functions of the organ in vivo, would be a great support to search for more sustainable feed ingredients in aquaculture. We previously demonstrated that proliferation or differentiation of rainbow trout intestinal cell lines is dictated by the culture environment. The aim of the present work was to develop a culture platform that can efficiently promote cell differentiation into mature enterocytes. We compared four options, seeding the RTpiMI cell line derived from the proximal intestine on (1) polyethylene terephthalate (PET) culture inserts ThinCert™ (TC), (2) TC coated with the solubilized basement membrane matrix Matrigel^® (MM), (3) TC with the rainbow trout fibroblast cell line RTskin01 embedded within the Matrigel^® matrix (MMfb), or (4) the highly porous polystyrene scaffold Alvetex^® populated with the abovementioned fibroblast cell line (AV). We evaluated the presence of columnar cells with a clear polarization of brush border enzymes, the formation of an efficient barrier with a significant increase in transepithelial electrical resistance (TEER), and its ability to prevent the paracellular flux of large molecules but allow the transit of small compounds (proline and glucose) from the apical to the basolateral compartment. All parameters improved moving from the simplest (TC) through the more complex platforms. The presence of fibroblasts was particularly effective in enhancing epithelial cell differentiation within the AV platform recreating more closely the complexity of the intestinal mucosa, including the presence of extracellular vesicles between fibroblasts and epithelial cells.

Strategic outline of interventions targeting extracellular matrix for promoting healthy longevity

The extracellular matrix (ECM), composed of interlinked proteins outside of cells, is an important component of the human body that helps maintain tissue architecture and cellular homeostasis. As people age, the ECM undergoes changes that can lead to age-related morbidity and mortality. Despite its importance, ECM aging remains understudied in the field of geroscience. In this review, we discuss the core concepts of ECM integrity, outline the age-related challenges and subsequent pathologies and diseases, summarize diagnostic methods detecting a faulty ECM, and provide strategies targeting ECM homeostasis. To conceptualize this, we built a technology research tree to hierarchically visualize possible research sequences for studying ECM aging. This strategic framework will hopefully facilitate the development of future research on interventions to restore ECM integrity, which could potentially lead to the development of new drugs or therapeutic interventions promoting health during aging.

Sclerosing Variant of Adenoid Cystic Carcinoma - A Case Report on the Role of Sclerosis in the Prognostic Outcome

Rationale

Sclerosing variant of adenoid cystic carcinoma (SACC) is a rare variant of adenoid cystic carcinoma (ACC) with only two cases in the literature. In this article, we report two cases of SACCs and attempt to explain the reason for sclerosis and its association with the disease outcome.

Patient Concerns

The first patient is a 43-year-old Dravidian Indian female with a chief complaint of pain and swelling in the right posterior cheek region of four months' duration. The second patient is an 8-year-old boy with a well-defined swelling in the left cheek region.

Diagnosis

Both these cases were diagnosed as sclerosing variants of ACC.

Treatment

The tumour was surgically excised for both patients.

Outcomes

Both the patients had no signs of residual disease/recurrence.

Take-away Lessons

We opine that the dense sclerotic stroma may have a preventing role in tumour cell growth and progression.

In Vitro Antioxidant and Fibroblast Migration Activities of Fractions Eluded from Dichloromethane Leaf Extract of Marantodes pumilum

(1) The complexity of diabetes and diabetic wound healing remains a therapeutic challenge because proper and systematic wound care and management are essential to prevent chronic microbial infection and mechanical damage to the skin. Marantodes pumilum, locally known as 'Kacip Fatimah', is an herb that has been previously reported to possess anti-inflammatory, analgesic, antinociceptive and antipyretic properties. The current study aims to assess the antioxidant and fibroblast cell migration activities of the fractions eluded from the dichloromethane extract of M. pumilum leaves. (2) The total antioxidant capacity of M. pumilum was assessed using the total proanthocyanidins and phosphomolybdenum assays, while DPPH, nitric oxide, hydrogen peroxide and superoxide free radical scavenging assays were tested to determine the antioxidant potential of M. pumilum. An in vitro scratch wound assay was performed to measure the fibroblast cell migration rate using normal and insulin-resistant human dermal fibroblast cells. (3) All M. pumilum fractions exhibited good antioxidant and fibroblast cell migration activity, among which fractions A and E displayed the greatest effect. (4) M. pumilum's fibroblast migration activity could be attributed to its strong antioxidant properties along with its previously reported properties.

Protease-Responsive Hydrogel Microparticles for Intradermal Drug Delivery

Protease-responsive multi-arm polyethylene glycol-based microparticles with biscysteine peptide crosslinkers (CGPGG↓LAGGC) were obtained for intradermal drug delivery through inverse suspension photopolymerization. The average size of the spherical hydrated microparticles was ∼40 μm after crosslinking, making them attractive as a skin depot and suitable for intradermal injections, as they are readily dispensable through 27G needles. The effects of exposure to matrix metalloproteinase 9 (MMP-9) on the microparticles were evaluated by scanning electron microscopy and atomic force microscopy, demonstrating partial network destruction and decrease in elastic moduli. Given the recurring course of many skin diseases, the microparticles were exposed to MMP-9 in a flare-up mimicking fashion (multiple-time exposure), showing a significant increase in release of tofacitinib citrate (TC) from the MMP-responsive microparticles, which was not seen for the non-responsive microparticles (polyethylene glycol dithiol crosslinker). It was found that the degree of multi-arm complexity of the polyethylene glycol building blocks can be utilized to tune not only the release profile of TC but also the elastic moduli of the hydrogel microparticles, with Young's moduli ranging from 14 to 140 kPa going from 4-arm to 8-arm MMP-responsive microparticles. Finally, cytotoxicity studies conducted with skin fibroblasts showed no reduction in metabolic activity after 24 h exposure to the microparticles. Overall, these findings demonstrate that protease-responsive microparticles exhibit the properties of interest for intradermal drug delivery.

Mechanoepigenetic regulation of extracellular matrix homeostasis via Yap and Taz

Cells integrate mechanical cues to direct fate specification to maintain tissue function and homeostasis. While disruption of these cues is known to lead to aberrant cell behavior and chronic diseases, such as tendinopathies, the underlying mechanisms by which mechanical signals maintain cell function are not well understood. Here, we show using a model of tendon de-tensioning that loss of tensile cues in vivo acutely changes nuclear morphology, positioning, and expression of catabolic gene programs, resulting in subsequent weakening of the tendon. In vitro studies using paired ATAC/RNAseq demonstrate that the loss of cellular tension rapidly reduces chromatin accessibility in the vicinity of Yap/Taz genomic targets while also increasing expression of genes involved in matrix catabolism. Concordantly, the depletion of Yap/Taz elevates matrix catabolic expression. Conversely, overexpression of Yap results in a reduction of chromatin accessibility at matrix catabolic gene loci, while also reducing transcriptional levels. The overexpression of Yap not only prevents the induction of this broad catabolic program following a loss of cellular tension, but also preserves the underlying chromatin state from force-induced alterations. Taken together, these results provide novel mechanistic details by which mechanoepigenetic signals regulate tendon cell function through a Yap/Taz axis.

Theroleofinterleukin-1familyinfibroticdiseases

Fibrosis refers to the phenomenon that fibrous connective tissues are increased and parenchymal cells are decreased in organs or tissues such as lung, heart, liver, kidney, skin and so on. It usually occurs at the late stage of repair of chronic or recurrent tissue damage. Fibrotic disease is the main factor for the morbidity and mortality of all tissues and organ systems. Long-term fibrosis can lead to organ and tissue dysfunction and even failure. Interleukin -1 family cytokines are a series of classical inflammatory factors and involved in the occurrence and development process of multiple fibrotic diseases, its biological function, relationship with diseases and application are more and more favored by scientists from various countries. So far, 11 cytokines and 10 receptors of IL-1 family have been identified. In this paper, the cytokines, receptors, signaling pathways and biological functions of IL-1 family are summarized, and the correlation with fibrosis diseases is analyzed.

Topical Delivery of Cell-Penetrating Peptide-Modified Human Growth Hormone for Enhanced Wound Healing

Protein drugs have been emerging as a class of promising therapeutics. However, their topical application has been limited by their high molecular weight and poor permeability to the cell membrane. In this study, we aimed to enhance human growth hormone (hGH) permeability for topical application by conjugation of TAT peptide, a cell-penetrating peptide, to hGH via crosslinker. After TAT was conjugated to hGH, TAT-hGH was purified by affinity chromatography. TAT-hGH significantly increased cell proliferation compared with the control. Interestingly, the effect of TAT-hGH was higher than hGH at the same concentration. Furthermore, the conjugation of TAT to hGH enhanced the permeability of TAT-hGH across the cell membrane without affecting its biological activity in vitro. In vivo, the topical application of TAT-hGH into scar tissue markedly accelerated wound healing. Histological results showed that TAT-hGH dramatically promoted the re-epithelialization of wounds in the initial stage. These results demonstrate TAT-hGH as a new therapeutic potential drug for wound healing treatment. This study also provides a new method for topical protein application via enhancement of their permeability.

The Fabrication of Gelatin-Elastin-Nanocellulose Composite Bioscaffold as a Potential Acellular Skin Substitute

Gelatin usage in scaffold fabrication is limited due to its lack of enzymatic and thermal resistance, as well as its mechanical weakness. Hence, gelatin requires crosslinking and reinforcement with other materials. This study aimed to fabricate and characterise composite scaffolds composed of gelatin, elastin, and cellulose nanocrystals (CNC) and crosslinked with genipin. The scaffolds were fabricated using the freeze-drying method. The composite scaffolds were composed of different concentrations of CNC, whereas scaffolds made of pure gelatin and a gelatin-elastin mixture served as controls. The physicochemical and mechanical properties of the scaffolds, and their cellular biocompatibility with human dermal fibroblasts (HDF), were evaluated. The composite scaffolds demonstrated higher porosity and swelling capacity and improved enzymatic resistance compared to the controls. Although the group with 0.5% (w/v) CNC recorded the highest pore size homogeneity, the diameters of most of the pores in the composite scaffolds ranged from 100 to 200 μm, which is sufficient for cell migration. Tensile strength analysis revealed that increasing the CNC concentration reduced the scaffolds' stiffness. Chemical analyses revealed that despite chemical and structural alterations, both elastin and CNC were integrated into the gelatin scaffold. HDF cultured on the scaffolds expressed collagen type I and α-SMA proteins, indicating the scaffolds' biocompatibility with HDF. Overall, the addition of elastin and CNC improved the properties of gelatin-based scaffolds. The composite scaffolds are promising candidates for an acellular skin substitute.

Tumour-derived exosomal piR-25783 promotes omental metastasis of ovarian carcinoma by inducing the fibroblast to myofibroblast transition

Ovarian carcinoma inherently possesses a distinct metastatic organotropism for the adipose-rich omentum, contributing to disease progression. Although the premetastatic microenvironment (PMM) has been known to often play a prometastatic role during the process, incomplete mechanistic insight into PMM formation has prevented its therapeutic targeting. Omental fibroblasts can be activated by tumour cells to differentiate into myofibroblasts, termed the fibroblast-to-myofibroblast transition (FMT), which, in turn, enhances cancer aggressiveness. Here, we report crosstalk between cancer cells and omental fibroblasts through exosomal piR-25783, which fuels tumour metastasis. Tumour cell-secreted exosomal piR-25783 activates the TGF-β/SMAD2/SMAD3 pathway in fibroblasts and promotes the FMT in the omentum along with the secretion of various cytokines and elevation of proliferative, migratory, and invasive properties, contributing to the formation of PMMs. Furthermore, piR-25783-induced myofibroblasts promote tumour implantation and growth in the omentum. In addition, the overexpression of piR-25783 in ovarian carcinoma is associated with unfavourable clinicopathological characteristics and shorter survival. In this study, we provide molecular, functional, and translational evidence suggesting that exosomal piR-25783 plays an important role in the formation of PMMs and the development of metastatic diseases in vitro and in vivo and may serve as a potential therapeutic target for ovarian carcinoma with metastasis.

Role of fibroblast plasticity and heterogeneity in modulating angiogenesis and healing in the diabetic foot ulcer

Chronic diabetic foot ulcers (DFUs) are an important clinical issue faced by clinicians despite the advanced treatment strategies consisting of wound debridement, off-loading, medication, wound dressings, and keeping the ulcer clean. Non-healing DFUs are associated with the risk of amputation, increased morbidity and mortality, and economic stress. Neo-angiogenesis and granulation tissue formation are necessary for physiological DFU healing and acute inflammation play a key role in healing. However, chronic inflammation in association with diabetic complications holds the ulcer in the inflammatory phase without progressing to the resolution phase contributing to non-healing. Fibroblasts acquiring myofibroblasts phenotype contribute to granulation tissue formation and angiogenesis. However, recent studies suggest the presence of five subtypes of fibroblast population and of changing density in non-healing DFUs. Further, the association of fibroblast plasticity and heterogeneity with wound healing suggests that the switch in fibroblast phenotype may affect wound healing. The fibroblast phenotype shift and altered function may be due to the presence of chronic inflammation or a diabetic wound microenvironment. This review focuses on the role of fibroblast plasticity and heterogeneity, the effect of hyperglycemia and inflammatory cytokines on fibroblasts, and the interaction of fibroblasts with other cells in diabetic wound microenvironment in the perspective of DFU healing. Next, we summarize secretory, angiogenic, and angiostatic phenotypes of fibroblast which have been discussed in other organ systems but not in relation to DFUs followed by the perspective on the role of their phenotypes in promoting angiogenesis in DFUs.

Substrate stiffness controls proinflammatory responses in human gingival fibroblasts

Soft gingiva is often compromised in gingival health; however, the underlying biological mechanisms remain unknown. Extracellular matrix (ECM) stiffness is involved in the progression of various fibroblast-related inflammatory disorders via cellular mechanotransduction. Gingival stiffness might regulate cellular mechanotransduction-mediated proinflammatory responses in gingival fibroblasts. This in vitro study aims to investigate the effects of substrate stiffness on proinflammatory responses in human gingival fibroblasts (hGFs). The hGFs isolated from two healthy donors cultured on type I collagen-coated polydimethylsiloxane substrates with different stiffnesses, representing soft (5 kPa) or hard (25 kPa) gingiva. Expression levels of proinflammatory mediators, prostaglandin E2 or interleukin-1β, in hGFs were significantly higher with the soft substrate than with the hard substrate, even without and with lipopolysaccharide (LPS) to induce inflammation. Expression levels of gingival ECM and collagen cross-linking agents in hGFs were downregulated more with the soft substrate than with the hard substrate through 14 days of culture. The soft substrate suppressed the expression of mechanotransduction-related transcriptional factors and activated the expression of inflammation-related factors, whereas the hard substrate demonstrated the opposite effects. Soft substrate induced proinflammatory responses and inhibition of ECM synthesis in hGFs by inactivating cellular mechanotransduction. This supports the importance of ECM stiffness in gingival health.

Anti-apoptotic and anti-fibrotic efficacy of exercise training in hypertensive hearts: A systematic review

Background

This review aims to summarize the antiapoptotic, pro-survival, and antifibrotic effects of exercise training in hypertensive hearts.

Methods

Keyword searches were conducted in PubMed, Web of Science, and Scopus in May 2021. Research published in English on the effects of exercise training on the apoptosis, survival, and fibrosis pathways in hypertension was included. The CAMARADES checklist was used to determine the quality of the studies. Two reviewers independently implemented predesigned protocols for the search and selection of studies, the assessment of study quality, and the evaluation of the strength of evidence.

Results

Eleven studies were included after selection. The duration of the exercise training ranged from 5 to 27 weeks. Nine studies showed that exercise training improved cardiac survival rates by increasing IGF-1, IGF-1 receptor, p-PI3K, Bcl-2, HSP 72, and p-Akt. Furthermore, 10 studies showed that exercise training reduced apoptotic pathways by downregulating Bid, t-Bid, Bad, Bak, Bax, TNF, and FADD. Finally, two studies reported the modification and subsequent improvement of physiological characteristics of fibrosis and decreased MAPK p38 and PTEN levels by exercise training in the left ventricle of the heart.

Conclusions

The findings of the review showed that exercise training could improve cardiac survival rates and attenuate cardiac apoptotic and fibrotic pathways in hypertension, suggesting that exercise training could act as a therapeutic approach to prevent hypertension-induced cardiac apoptosis and fibrosis.

Systematic Review Registration

https://www.crd.york.ac.uk, identifier: CRD42021254118.

In vitro bioreactor for mechanical control and characterization of tissue constructs

Cardiac fibrosis is a key contributor to the onset and progression of heart failure and occurs from extracellular matrix accumulation via activated cardiac fibroblasts. Cardiac fibroblasts activate in response to mechanical stress and have been studied in the past by applying forces and deformations to three-dimensional, cell-seeded gels and tissue constructs in vitro. Unfortunately, previous stretching platforms have traditionally not enabled mechanical property assessment to be performed with an efficient throughput, thereby limiting the full potential of in vitro mechanobiology studies. We have developed a novel in vitro platform to study cell-populated tissue constructs under dynamic mechanical stimulation while also performing repeatable, non-destructive stress-strain tests in living constructs. Additionally, this platform can perform these tests across all constructs in a multi-well plate simultaneously, providing exciting potential for direct, functional readouts in future screening applications. In our pilot application, we showed that cyclically stretching cell-populated tissue constructs composed of murine cardiac fibroblasts within a 3D fibrin matrix leads to collagen accumulation and increased tissue stiffness over a three-day time course. Results of this study validate our platform's ability to apply mechanical loads to tissues while performing live mechanical analyses to observe cell-mediated tissue remodeling.

Himatanthus bracteatus-Composed In Situ Polymerizable Hydrogel for Wound Healing

The Himatanthus genus presents anti-inflammatory, antioxidant activities, suggesting potential wound-healing properties. This study aimed to develop and analyze the wound-healing properties of a photopolymerizable gelatin-based hydrogel (GelMA) containing an ethanolic extract of Himatanthus bracteatus in a murine model. The extract was obtained under high pressure conditions, incorporated (2%) into the GelMA (GelMA-HB), and physically characterized. The anti-inflammatory activity of the extract was assessed using a carrageenan-induced pleurisy model and the GelMA-HB scarring properties in a wound-healing assay. The extract reduced IL-1β and TNF-α levels (48.5 ± 6.7 and 64.1 ± 4.9 pg/mL) compared to the vehicle (94.4 ± 2.3 pg/mL and 106.3 ± 5.7 pg/mL; p < 0.001). GelMA-HB depicted significantly lower swelling and increased resistance to mechanical compression compared to GelMA (p < 0.05). GelMA-HB accelerated wound closure over the time course of the experiment (p < 0.05) and promoted a significantly greater peak of myofibroblast differentiation (36.1 ± 6.6 cells) and microvascular density (23.1 ± 0.7 microvessels) on day 7 in comparison to GelMA (31.9 ± 5.3 cells and 20.2 ± 0.6 microvessels) and the control (25.8 ± 4.6 cells and 17.5 ± 0.5 microvessels) (p < 0.05). In conclusion, GelMA-HB improved wound healing in rodents, probably by modulating the inflammatory response and myofibroblastic and microvascular differentiation.

Matrix Adhesiveness Regulates Myofibroblast Differentiation from Vocal Fold Fibroblasts in a Bio-orthogonally Cross-linked Hydrogel

Repeated mechanical and chemical insults cause an irreversible alteration of extracellular matrix (ECM) composition and properties, giving rise to vocal fold scarring that is refractory to treatment. Although it is well known that fibroblast activation to myofibroblast is the key to the development of the pathology, the lack of a physiologically relevant in vitro model of vocal folds impedes mechanistic investigations on how ECM cues promote myofibroblast differentiation. Herein, we describe a bio-orthogonally cross-linked hydrogel platform that recapitulates the alteration of matrix adhesiveness due to enhanced fibronectin deposition when vocal fold wound healing is initiated. The synthetic ECM (sECM) was established via the cycloaddition reaction of tetrazine (Tz) with slow (norbornene, Nb)- and fast (trans-cyclooctene, TCO)-reacting dienophiles. The relatively slow Tz-Nb ligation allowed the establishment of the covalent hydrogel network for 3D cell encapsulation, while the rapid and efficient Tz-TCO reaction enabled precise conjugation of the cell-adhesive RGDSP peptide in the hydrogel network. To mimic the dynamic changes of ECM composition during wound healing, RGDSP was conjugated to cell-laden hydrogel constructs via a diffusion-controlled bioorthognal ligation method 3 days post encapsulation. At a low RGDSP concentration (0.2 mM), fibroblasts residing in the hydrogel remained quiescent when maintained in transforming growth factor beta 1 (TGF-β1)-conditioned media. However, at a high concentration (2 mM), RGDSP potentiated TGF-β1-induced myofibroblast differentiation, as evidenced by the formation of an actin cytoskeleton network, including F-actin and alpha-smooth muscle actin. The RGDSP-driven fibroblast activation to myofibroblast was accompanied with an increase in the expression of wound healing-related genes, the secretion of profibrotic cytokines, and matrix contraction required for tissue remodeling. This work represents the first step toward the establishment of a 3D hydrogel-based cellular model for studying myofibroblast differentiation in a defined niche associated with vocal fold scarring.