The bright side of fibroblasts: molecular signature and regenerative cues in major organs

Positional information modulates transient regeneration-activated cell states during vertebrate appendage regeneration

Injury is common in the life of organisms. Because the extent of damage cannot be predicted, injured organisms must determine how much tissue needs to be restored. Although it is known that amputation position affects the regeneration speed of appendages, mechanisms conveying positional information remain unclear. We investigated tissue dynamics in regenerating caudal fins of the African killifish (Nothobranchius furzeri) and found position-specific, differential spatial distribution modulation, persistence, and magnitude of proliferation. Single-cell RNA sequencing revealed a transient regeneration-activated cell state (TRACS) in the basal epidermis that is amplified to match a given amputation position and expresses components and modifiers of the extracellular matrix (ECM). Notably, CRISPR-Cas9-mediated deletion of the ECM modifier sequestosome 1 (sqstm1) increased the regenerative capacity of distal injuries, suggesting that regeneration growth rate can be uncoupled from amputation position. We propose that basal epidermis TRACS transduce positional information to the regenerating blastema by remodeling the ECM.

Customized Vascular Repair Microenvironment: Poly(lactic acid)-Gelatin Nanofibrous Scaffold Decorated with bFGF and Ag@Fe3O4 Core-Shell Nanowires

Vascular defects caused by trauma or vascular diseases can significantly impact normal blood circulation, resulting in serious health complications. Vascular grafts have evolved as a popular approach for vascular reconstruction with promising outcomes. However, four of the greatest challenges for successful application of small-diameter vascular grafts are (1) postoperative anti-infection, (2) preventing thrombosis formation, (3) utilizing the inflammatory response to the graft to induce tissue regeneration and repair, and (4) noninvasive monitoring of the scaffold and integration. The present study demonstrated a basic fibroblast growth factor (bFGF) and oleic acid dispersed Ag@Fe3O4 core-shell nanowires (OA-Ag@Fe3O4 CSNWs) codecorated poly(lactic acid) (PLA)/gelatin (Gel) multifunctional electrospun vascular grafts (bAPG). The Ag@Fe3O4 CSNWs have sustained Ag+ release and exceptional photothermal capabilities to effectively suppress bacterial infections both in vitro and in vivo, noninvasive magnetic resonance imaging (MRI) modality to monitor the position of the graft, and antiplatelet adhesion properties to promise long-term patency. The gradually released bFGF from the bAPG scaffold promotes the M2 macrophage polarization and enhances the recruitment of macrophages, endothelial cells (ECs) and fibroblast cells. This significant regulation of diverse cell behavior has been proven to be beneficial to vascular repair and regeneration both in vitro and in vivo. Therefore, this study supplies a method to prepare multifunctional vascular-repair materials and is expected to represent a significant guidance and reference to the development of biomaterials for vascular tissue engineering.

Cellular and molecular mechanisms of skin wound healing

Wound healing is a complex process that involves the coordinated actions of many different tissues and cell lineages. It requires tight orchestration of cell migration, proliferation, matrix deposition and remodelling, alongside inflammation and angiogenesis. Whereas small skin wounds heal in days, larger injuries resulting from trauma, acute illness or major surgery can take several weeks to heal, generally leaving behind a fibrotic scar that can impact tissue function. Development of therapeutics to prevent scarring and successfully repair chronic wounds requires a fuller knowledge of the cellular and molecular mechanisms driving wound healing. In this Review, we discuss the current understanding of the different phases of wound healing, from clot formation through re-epithelialization, angiogenesis and subsequent scar deposition. We highlight the contribution of different cell types to skin repair, with emphasis on how both innate and adaptive immune cells in the wound inflammatory response influence classically studied wound cell lineages, including keratinocytes, fibroblasts and endothelial cells, but also some of the less-studied cell lineages such as adipocytes, melanocytes and cutaneous nerves. Finally, we discuss newer approaches and research directions that have the potential to further our understanding of the mechanisms underpinning tissue repair.

Vascular units as advanced living materials for bottom-up engineering of perfusable 3D microvascular networks

The timely establishment of functional neo-vasculature is pivotal for successful tissue development and regeneration, remaining a central challenge in tissue engineering. In this study, we present a novel (micro)vascularization strategy that explores the use of specialized "vascular units" (VUs) as building blocks to initiate blood vessel formation and create perfusable, stroma-embedded 3D microvascular networks from the bottom-up. We demonstrate that VUs composed of endothelial progenitor cells and organ-specific fibroblasts exhibit high angiogenic potential when embedded in fibrin hydrogels. This leads to the formation of VUs-derived capillaries, which fuse with adjacent capillaries to form stable microvascular beds within a supportive, extracellular matrix-rich fibroblastic microenvironment. Using a custom-designed biomimetic fibrin-based vessel-on-chip (VoC), we show that VUs-derived capillaries can inosculate with endothelialized microfluidic channels in the VoC and become perfused. Moreover, VUs can establish capillary bridges between channels, extending the microvascular network throughout the entire device. When VUs and intestinal organoids (IOs) are combined within the VoC, the VUs-derived capillaries and the intestinal fibroblasts progressively reach and envelop the IOs. This promotes the formation of a supportive vascularized stroma around multiple IOs in a single device. These findings underscore the remarkable potential of VUs as building blocks for engineering microvascular networks, with versatile applications spanning from regenerative medicine to advanced in vitro models.

MAPK Phosphatase-5 is required for TGF-β signaling through a JNK-dependent pathway

Mitogen-activated protein kinase (MAPK) phosphatases (MKPs) constitute members of the dual-specificity family of protein phosphatases that dephosphorylate the MAPKs. MKP-5 dephosphorylates the stress-responsive MAPKs, p38 MAPK and JNK, and has been shown to promote tissue fibrosis. Here, we provide insight into how MKP-5 regulates the transforming growth factor-β (TGF-β) pathway, a well-established driver of fibrosis. We show that MKP-5-deficient fibroblasts in response to TGF-β are impaired in SMAD2 phosphorylation at canonical and non-canonical sites, nuclear translocation, and transcriptional activation of fibrogenic genes. Consistent with this, pharmacological inhibition of MKP-5 is sufficient to block TGF-β signaling, and that this regulation occurs through a JNK-dependent pathway. By utilizing RNA sequencing and transcriptomic analysis, we identify TGF-β signaling activators regulated by MKP-5 in a JNK-dependent manner, providing mechanistic insight into how MKP-5 promotes TGF-β signaling. This study elucidates a novel mechanism whereby MKP-5-mediated JNK inactivation is required for TGF-β signaling and provides insight into the role of MKP-5 in fibrosis.

Neutrophil Extracellular Traps: A Crucial Factor in Post-Surgical Abdominal Adhesion Formation

Post-surgical abdominal adhesions, although poorly understood, are highly prevalent. The molecular processes underlying their formation remain elusive. This review aims to assess the relationship between neutrophil extracellular traps (NETs) and the generation of postoperative peritoneal adhesions and to discuss methods for mitigating peritoneal adhesions. A keyword or medical subject heading (MeSH) search for all original articles and reviews was performed in PubMed and Google Scholar. It included studies assessing peritoneal adhesion reformation after abdominal surgery from 2003 to 2023. After assessing for eligibility, the selected articles were evaluated using the Critical Appraisal Skills Programme checklist for qualitative research. The search yielded 127 full-text articles for assessment of eligibility, of which 7 studies met our criteria and were subjected to a detailed quality review using the Critical Appraisal Skills Programme (CASP) checklist. The selected studies offer a comprehensive analysis of adhesion pathogenesis with a special focus on the role of neutrophil extracellular traps (NETs) in the development of peritoneal adhesions. Current interventional strategies are examined, including the use of mechanical barriers, advances in regenerative medicine, and targeted molecular therapies. In particular, this review emphasizes the potential of NET-targeted interventions as promising strategies to mitigate postoperative adhesion development. Evidence suggests that in addition to their role in innate defense against infections and autoimmune diseases, NETs also play a crucial role in the formation of peritoneal adhesions after surgery. Therefore, therapeutic strategies that target NETs are emerging as significant considerations for researchers. Continued research is vital to fully elucidate the relationship between NETs and post-surgical adhesion formation to develop effective treatments.

Intra-peritoneal lavage of Zingiber officinale rhizome and its active constituent gingerol impede inflammation, angiogenesis, and fibrosis following post-operative peritoneal adhesion in male rats

Post-operative peritoneal adhesions (PA) are a common and important clinical problem. In this study, we focused on the ameliorative efficacy of ginger and gingerol compounds on surgical-induced peritoneal adhesion, and their strategies that disrupted the PA formation pathways to suppress their incidence. First, liquid chromatography-mass spectrometry (LC-MS) was established to separate and identify several chemical groups of ginger rhizome extract. In the next steps, male Wistar albino rats were randomly selected and divided into various groups, namely sham, control, ginger extract (0.6, 1.8, 5 %w/v), and gingerol (0.05, 0.1, 0.3, and 1 %w/v). Finally, we investigated the macroscopic parameters such as wound healing, body weight as well as spleen height and weight. In addition, visual peritoneal adhesion assessment was performed via Nair et al and Adhesion Scoring Scheme. Moreover, the microscopic parameters and biological assessment was performed via and immunoassays. The present findings revealed significant improvement in wound healing and reduction of the adhesion range, as Nair et al. and Adhesion Scoring Scheme scoring, in both the ginger and gingerol groups compared to the PA group (P < 0.05). Whereas, gingerol (0.3 % w/v) was able to increase the body weight in rats (P < 0.0001) at end stage of experiment. Also, inflammation, angiogenesis, and fibrosis were significantly decreased due to the downregulation of interleukin (IL)-6, tumor necrosis factor (TNF)-α, transforming growth factor (TGF)-β1, vascular endothelial growth factor (VEGF), respectively, in the ginger and gingerol groups compared to the PA group (P < 0.05). In contrast, the levels of IL-10 were increased in the ginger and gingerol groups compared to the control group (P < 0.01). Our results proved that ginger rhizome and gingerol, as novel therapeutic compounds, could be used to prevent PA for their beneficial anti-inflammatory as well as anti-fibrosis properties in clinical trials. However, further clinical studies are required to approve the effectiveness of ginger and gingerol.

Cell-homing and immunomodulatory composite hydrogels for effective wound healing with neovascularization

Wound healing in cases of excessive inflammation poses a significant challenge due to compromised neovascularization. Here, we propose a multi-functional composite hydrogel engineered to overcome such conditions through recruitment and activation of macrophages with adapted degradation of the hydrogel. The composite hydrogel (G-TSrP) is created by combining gelatin methacryloyl (GelMA) and nanoparticles (TSrP) composed of tannic acid (TA) and Sr2+. These nanoparticles are prepared using a one-step mineralization process assisted by metal-phenolic network formation. G-TSrP exhibits the ability to eliminate reactive oxygen species and direct polarization of macrophages toward M2 phenotype. It has been observed that the liberation of TA and Sr2+ from G-TSrP actively facilitate the recruitment and up-regulation of the expression of extracellular matrix remodeling genes of macrophages, and thereby, coordinate in vivo adapted degradation of the G-TSrP. Most significantly, G-TSrP accelerates angiogenesis despite the TA's inhibitory properties, which are counteracted by the released Sr2+. Moreover, G-TSrP enhances wound closure under inflammation and promotes normal tissue formation with strong vessel growth. Genetic analysis confirms macrophage-mediated wound healing by the composite hydrogel. Collectively, these findings pave the way for the development of biomaterials that promote wound healing by creating regenerative environment.

Comparison of the osteogenic potential of fibroblasts from different sources

OBJECTIVE

With the growing interest in the role of fibroblasts in osteogenesis, this study presents a comparative evaluation of the osteogenic potential of fibroblasts derived from three distinct sources: human gingival fibroblasts (HGFs), mouse embryonic fibroblasts (NIH3T3 cells), and mouse subcutaneous fibroblasts (L929 cells). MC3T3-E1 pre-osteoblast cells were employed as a positive control for osteogenic behavior.

DESIGN

Our assessment involved multiple approaches, including vimentin staining for cell origin verification, as well as ALP and ARS staining in conjunction with RT-PCR for osteogenic characterization.

RESULTS

Our findings revealed the superior osteogenic differentiation capacity of HGFs compared to MC3T3-E1 and NIH3T3 cells. Analysis of ALP staining confirmed that early osteogenic differentiation was most prominent in MC3T3-E1 cells at 7 days, followed by NIH3T3 and HGFs. However, ARS staining at 21 days demonstrated that HGFs produced the highest number of calcified nodules, indicating their robust potential for late-stage mineralization. This late-stage osteogenic potential of HGFs was further validated through RT-PCR analysis. In contrast, L929 cells displayed no significant osteogenic differentiation potential.

CONCLUSIONS

In light of these findings, HGFs emerge as the preferred choice for seed cells in bone tissue engineering applications. This study provides valuable insights into the potential utility of HGFs in the fields of bone tissue engineering and regenerative medicine.

Exploring the potential of bovine colostrum as a bioactive agent in human tissue regeneration: A comprehensive analysis of mechanisms of action and challenges to be overcome

The study examines bovine colostrum as a potent source of bioactive compounds, particularly growth factors, for tissue regeneration in humans. While previous research has hinted at therapeutic benefits, a comprehensive understanding of its mechanisms remains elusive, necessitating further investigation. This review analyzes nine selected scientific articles on bovine colostrum's bioactive potential in tissue regeneration. In vitro studies highlight its positive impact on cell behavior, including reduced proliferation and induced differentiation. Notably, optimal concentrations and specific colostrum components, such as extracellular vesicles and insoluble milk fat, show more favorable outcomes. In vivo studies underscore bovine colostrum as a promising natural resource for wound healing, despite some studies failing to identify associated benefits. Further research is crucial to unravel the intricate mechanisms, grasp the full potential in regenerative medicine, and develop more effective wound healing therapies. This refined understanding will pave the way for harnessing the complete regenerative potential of bovine colostrum in clinical applications.

Human Umbilical Cord Mesenchymal Stromal Cell-Derived Extracellular Vesicles Induce Fetal Wound Healing Features Revealed by Single-Cell RNA Sequencing

The potential of human umbilical cord mesenchymal stromal cell-derived extracellular vesicles (hucMSC-EVs) in wound healing is promising, yet a comprehensive understanding of how fibroblasts and keratinocytes respond to this treatment remains limited. This study utilizes single-cell RNA sequencing (scRNA-seq) to investigate the impact of hucMSC-EVs on the cutaneous wound microenvironment in mice. Through rigorous single-cell analyses, we unveil the emergence of hucMSC-EV-induced hematopoietic fibroblasts and MMP13+ fibroblasts. Notably, MMP13+ fibroblasts exhibit fetal-like expressions of MMP13, MMP9, and HAS1, accompanied by heightened migrasome activity. Activation of MMP13+ fibroblasts is orchestrated by a distinctive PIEZO1-calcium-HIF1α-VEGF-MMP13 pathway, validated through murine models and dermal fibroblast assays. Organotypic culture assays further affirm that these activated fibroblasts induce keratinocyte migration via MMP13-LRP1 interactions. This study significantly contributes to our understanding of fibroblast heterogeneities as well as intercellular interactions in wound healing and identifies hucMSC-EV-induced hematopoietic fibroblasts as potential targets for reprogramming. The therapeutic targets presented by these fibroblasts offer exciting prospects for advancing wound healing strategies.

Ovarian Cancer Cell-Conditioning Medium Induces Cancer-Associated Fibroblast Phenoconversion through Glucose-Dependent Inhibition of Autophagy

One aspect of ovarian tumorigenesis which is still poorly understood is the tumor-stroma interaction, which plays a major role in chemoresistance and tumor progression. Cancer-associated fibroblasts (CAFs), the most abundant stromal cell type in the tumor microenvironment, influence tumor growth, metabolism, metastasis, and response to therapy, making them attractive targets for anti-cancer treatment. Unraveling the mechanisms involved in CAFs activation and maintenance is therefore crucial for the improvement of therapy efficacy. Here, we report that CAFs phenoconversion relies on the glucose-dependent inhibition of autophagy. We show that ovarian cancer cell-conditioning medium induces a metabolic reprogramming towards the CAF-phenotype that requires the autophagy-dependent glycolytic shift. In fact, 2-deoxy-D-glucose (2DG) strongly hampers such phenoconversion and, most importantly, induces the phenoreversion of CAFs into quiescent fibroblasts. Moreover, pharmacological inhibition (by proline) or autophagy gene knockdown (by siBECN1 or siATG7) promotes, while autophagy induction (by either 2DG or rapamycin) counteracts, the metabolic rewiring induced by the ovarian cancer cell secretome. Notably, the nutraceutical resveratrol (RV), known to inhibit glucose metabolism and to induce autophagy, promotes the phenoreversion of CAFs into normal fibroblasts even in the presence of ovarian cancer cell-conditioning medium. Overall, our data support the view of testing autophagy inducers for targeting the tumor-promoting stroma as an adjuvant strategy to improve therapy success rates, especially for tumors with a highly desmoplastic stroma, like ovarian cancer.

Dual FGFR-targeting and pH-activatable ruthenium-peptide conjugates for targeted therapy of breast cancer

Dysregulation of Fibroblast Growth Factor Receptors (FGFRs) signaling has been associated with breast cancer, yet employing FGFR-targeted delivery systems to improve the efficacy of cytotoxic agents is still sparsely exploited. Herein, we report four new bi-functional ruthenium-peptide conjugates (RuPCs) with FGFR-targeting and pH-dependent releasing abilities, envisioning the selective delivery of cytotoxic Ru complexes to FGFR(+)-breast cancer cells, and controlled activation at the acidic tumoral microenvironment. The antiproliferative potential of the RuPCs and free Ru complexes was evaluated in four breast cancer cell lines with different FGFR expression levels (SKBR-3, MDA-MB-134-VI, MCF-7, and MDA-MB-231) and in human dermal fibroblasts (HDF), at pH 6.8 and pH 7.4 aimed at mimicking the tumor microenvironment and normal tissues/bloodstream pHs, respectively. The RuPCs showed higher cytotoxicity in cells with higher level of FGFR expression at acidic pH. Additionally, RuPCs showed up to 6-fold higher activity in the FGFR(+) breast cancer lines compared to the normal cell line. The release profile of Ru complexes from RuPCs corroborates the antiproliferative effects observed. Remarkably, the cytotoxicity and releasing ability of RuPCs were shown to be strongly dependent on the conjugation of the peptide position in the Ru complex. Complementary molecular dynamic simulations and computational calculations were performed to help interpret these findings at the molecular level. In summary, we identified a lead bi-functional RuPC that holds strong potential as a FGFR-targeted chemotherapeutic agent.

Comapping Cellular Content and Extracellular Matrix with Hemodynamics in Intact Arterial Tissues Using Scanning Immunofluorescent Multiphoton Microscopy

Deviation of blood flow from an optimal range is known to be associated with the initiation and progression of vascular pathologies. Important open questions remain about how the abnormal flow drives specific wall changes in pathologies such as cerebral aneurysms where the flow is highly heterogeneous and complex. This knowledge gap precludes the clinical use of readily available flow data to predict outcomes and improve treatment of these diseases. As both flow and the pathological wall changes are spatially heterogeneous, a crucial requirement for progress in this area is a methodology for acquiring and comapping local vascular wall biology data with local hemodynamic data. Here, we developed an imaging pipeline to address this pressing need. A protocol that employs scanning multiphoton microscopy was developed to obtain three-dimensional (3D) datasets for smooth muscle actin, collagen, and elastin in intact vascular specimens. A cluster analysis was introduced to objectively categorize the smooth muscle cells (SMC) across the vascular specimen based on SMC actin density. Finally, direct quantitative comparison of local flow and wall biology in 3D intact specimens was achieved by comapping both heterogeneous SMC data and wall thickness to patient-specific hemodynamic results.

Copper(II) Complexes with 2,2':6',2″-Terpyridine Derivatives Displaying Dimeric Dichloro-μ-Bridged Crystal Structure: Biological Activities from 2D and 3D Tumor Spheroids to In Vivo Models

Eight 2,2':6',2″-terpyridines, substituted at the 4'-position with aromatic groups featuring variations in π-conjugation, ring size, heteroatoms, and methoxy groups, were employed to enhance the antiproliferative potential of [Cu2Cl2(R-terpy)2](PF6)2. Assessing the cytotoxicity in A2780 (ovarian carcinoma), HCT116 (colorectal carcinoma), and HCT116DoxR (colorectal carcinoma resistant to doxorubicin) and normal primary fibroblasts revealed that Cu(II) complexes with 4-quinolinyl, 4-methoxy-1-naphthyl, 2-furanyl, and 2-pyridynyl substituents showed superior therapeutic potential in HCT116DoxR cells with significantly reduced cytotoxicity in normal fibroblasts (42-129× lower). Besides their cytotoxicity, the Cu(II) complexes are able to increase intracellular ROS and interfere with cell cycle progression, leading to cell death by apoptosis and autophagy. Importantly, they demonstrated antimetastatic and antiangiogenic properties without in vivo toxicity. In accordance with their nuclear accumulation, the Cu(II) complexes are able to cleave pDNA and interact with bovine serum albumin, which is a good indication of their ability for internalization and transport toward tumor cells.

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.

The role of positional information in determining dermal fibroblast diversity

The largest mammalian organ, skin, consisting of a dermal connective tissue layer that underlies and supports the epidermis, acts as a protective barrier that excludes external pathogens and disseminates sensory signals emanating from the local microenvironment. Dermal connective tissue is comprised of a collagen-rich extracellular matrix (ECM) that is produced by connective tissue fibroblasts resident within the dermis. When wounded, a tissue repair program is induced whereby fibroblasts, in response to alterations in the microenvironment, produce new ECM components, resulting in the formation of a scar. Failure to terminate the normal tissue repair program causes fibrotic conditions including: hypertrophic scars, keloids, and the systemic autoimmune connective tissue disease scleroderma (systemic sclerosis, SSc). Histological and single-cell RNA sequencing (scRNAseq) studies have revealed that fibroblasts are heterogeneous and highly plastic. Understanding how this diversity contributes to dermal homeostasis, wounding, fibrosis, and cancer may ultimately result in novel anti-fibrotic therapies and personalized medicine. This review summarizes studies supporting this concept.

Fibroblast function recovery through rejuvenation effect of nanovesicles extracted from human adipose-derived stem cells irradiated with red light

Fibroblasts (hDFs) are widely employed for skin regeneration and the treatment of various skin disorders, yet research were rarely investigated about restoration of diminished therapeutic efficacy due to cell senescence. The application of stem cell and stem cell-derived materials, exosomes, were drawn attention for the restoration functionality of fibroblasts, but still have limitation for unintended side effect or low yield. To advance, stem cell-derived nanovesicle (NV) have developed for effective therapeutic reagents with high yield and low risk. In this study, we have developed a method using red light irradiated human adipose-derived stem cells (hADSCs) derived NV (R-NVs) for enhancing the therapeutic efficacy and rejuvenating hDFs. Through red light irradiation, we were able to significantly increase the content of stemness factors and angiogenic biomolecules in R-NVs. Treatment with these R-NVs was found to enhance the migration ability and leading to rejuvenation of old hDFs to levels similar to those of young hDFs. In subsequent in vivo experiments, the treatment of old hDFs with R-NVs demonstrated a superior skin wound healing effect, surpassing that of young hDFs. In summary, this study successfully induced rejuvenation and leading to increased therapeutic efficacy to R-NVs treated old hDFs previously considered as biowaste.

Pterostilbene: a potential therapeutic agent for fibrotic diseases

Fibrosis is a prevailing pathology in chronic diseases and accounts for 45% of deaths in developed countries. This condition is primarily identified by the transformation of fibroblasts into myofibroblasts and the overproduction of extracellular matrix (ECM) by myofibroblasts. Pterostilbene (PTS) is a natural analogue of resveratrol and is most commonly found in blueberries. Research has shown that PTS exerts a wide range of pharmacological effects, such as antioxidant, anti-inflammatory, and anticancer effects. As a result, PTS has the potential to prevent and cure numerous diseases. Emerging evidence has indicated that PTS can alleviate myocardial fibrosis, renal fibrosis, pulmonary fibrosis, hepatic fibrosis, and colon fibrosis via the inhibition of inflammation, oxidative stress, and fibrogenesis effects in vivo and in vitro, and the potential mechanisms are linked to various pathways, including transforming growth factor-β1 (TGF-β1)/small mother against decapentaplegic proteins (Smads) signalling, the reactive oxygen species (ROS)-driven Pitx2c/mir-15b pathway, nuclear factor kappa B (NF-κB) signalling, Kelch-like epichlorohydrin-associated protein-1 (Keap-1)/NF-E2-related factor-2 (Nrf2) cascade, the NLR family pyridine structure domain 3 (NLRP3) pathway, the Janus kinase-2 (JAK2)/signal transducer and activator of transcription 3 (STAT3) pathway, and the Src/STAT3 pathway. In this review, we comprehensively summarize the antifibrotic effects of PTS both in vivo and in vitro and the pharmacological mechanisms, pharmacokinetics, and toxicology of PTS and provide insights into and strategies for exploring promising agents for the treatment of fibrosis.

Green tea and hyaluronic acid gel enhance fibroblast activation and improves the gingival healing post-third molar extraction

This study evaluates the effects of a green tea (Camellia sinensis) and hyaluronic acid gel on fibroblast activity and alveolar bone repair following third molar extractions. By examining the gene expression related to cell survival, proliferation, and angiogenesis, the study bridges in vitro findings with clinical outcomes in a split-mouth randomized trial. Human fibroblasts were exposed to the treatment gel, analysing gene expression through RT-qPCR. Twenty participants undergoing bilateral third molar extractions received the test gel on one side and a placebo on the other. Assessments included patient-reported outcomes, professional evaluations, and radiographic analyses at multiple postoperative intervals. The test gel significantly enhanced AKT, CDKs, and VEGF gene expressions, indicating a positive effect on angiogenesis and cell proliferation. Clinically, it resulted in reduced exudate, swelling, and secondary interventions, with radiographs showing improved alveolar bone density after 90 days. The green tea and hyaluronic acid gel significantly improves soft tissue and bone healing post-extraction, offering a promising adjunctive therapy for enhancing postoperative recovery. This gel represents a novel adjuvant treatment option for facilitating improved healing outcomes after third molar extractions, highlighting its potential utility in clinical dental practice.

Assessing the fate and contribution of Foxd1-expressing embryonic precursors and their progeny in palatal development, homeostasis and excisional repair

Oral mucosal tissues heal rapidly with minimal scarring, although palatal mucosa can be associated with excessive fibrosis in response to injury. Investigations on the balance between neovascularization and tissue repair suggests regulation of angiogenesis is an important determinant of repair versus scarring. Associated with pericyte mediated fibrosis in kidney injury, FoxD1 is implicated in growth centres during cranio-facial development, although which cell lineages are derived from these embryonic populations in development and in adult animals is unknown. Using a lineage tracing approach, we assessed the fate of embryonic Foxd1-expressing progenitor cells and their progeny in palatal development and during wound healing in adult mice. During palatal development as well as in post-natal tissues, Foxd1-lineage progeny were associated with the vasculature and the epineurium. Post-injury, de novo expression of FoxD1 was not detectable, although Foxd1-lineage progeny expanded while exhibiting low association with the fibroblast/myofibroblast markers PDGFα, PDGFβ, vimentin, α-smooth muscle actin, as well as the neuronal associated markers S100β and p75NTR. Foxd1-lineage progeny were primarily associated with CD146, CD31, and to a lesser extent CD105, remaining in close proximity to developing neovascular structures. Our findings demonstrate that FoxD1 derived cells are predominantly associated with the palatal vasculature and provide strong evidence that FoxD1 derived cells do not give rise to populations involved directly in the scarring of the palate.

Linking NLRP3 inflammasome and pulmonary fibrosis: mechanistic insights and promising therapeutic avenues

Pulmonary fibrosis is a devastating disorder distinguished by redundant inflammation and matrix accumulation in the lung interstitium. The early inflammatory cascade coupled with recurring tissue injury orchestrates a set of events marked by perturbed matrix hemostasis, deposition of matrix proteins, and remodeling in lung tissue. Numerous investigations have corroborated a direct correlation between the NLR family pyrin domain-containing 3 (NLRP3) activation and the development of pulmonary fibrosis. Dysregulated activation of NLRP3 within the pulmonary microenvironment exacerbates inflammation and may incite fibrogenic responses. Nevertheless, the precise mechanisms through which the NLRP3 inflammasome elicits pro-fibrogenic responses remain inadequately defined. Contemporary findings suggest that the pro-fibrotic consequences stemming from NLRP3 signaling primarily hinge on the action of interleukin-1β (IL-1β). IL-1β instigates IL-1 receptor signaling, potentiating the activity of transforming growth factor-beta (TGF-β). This signaling cascade, in turn, exerts influence over various transcription factors, including SNAIL, TWIST, and zinc finger E-box-binding homeobox 1 (ZEB 1/2), which collectively foster myofibroblast activation and consequent lung fibrosis. Here, we have connected the dots to illustrate how the NLRP3 inflammasome orchestrates a multitude of signaling events, including the activation of transcription factors that facilitate myofibroblast activation and subsequent lung remodeling. In addition, we have highlighted the prominent role played by various cells in the formation of myofibroblasts, the primary culprit in lung fibrosis. We also provided a concise overview of various compounds that hold the potential to impede NLRP3 inflammasome signaling, thus offering a promising avenue for the treatment of pulmonary fibrosis.

Cell Surface Modification-Mediated Primary Intestinal Epithelial Cell Culture Platforms for Assessing Host-Microbiota Interactions

Background: Intestinal epithelial cells (IECs) play a crucial role in regulating the symbiotic relationship between the host and the gut microbiota, thereby allowing them to modulate barrier function, mucus production, and aberrant inflammation. Despite their importance, establishing an effective ex vivo culture method for supporting the prolonged survival and function of primary IECs remains challenging. Here, we aim to develop a novel strategy to support the long-term survival and function of primary IECs in response to gut microbiota by employing mild reduction of disulfides on the IEC surface proteins with tris(2-carboxyethyl)phosphine. Methods: Recognizing the crucial role of fibroblast-IEC crosstalk, we employed a cell surface modification strategy, establishing layer-to-layer contacts between fibroblasts and IECs. This involved combining negatively charged chondroitin sulfate on cell surfaces with a positively charged chitosan thin film between cells, enabling direct intercellular transfer. Validation included assessments of cell viability, efficiency of dye transfer, and IEC function upon lipopolysaccharide (LPS) treatment. Results: Our findings revealed that the layer-by-layer co-culture platform effectively facilitates the transfer of small molecules through gap junctions, providing vital support for the viability and function of primary IECs from both the small intestine and colon for up to 5 days, as evident by the expression of E-cadherin and Villin. Upon LPS treatment, these IECs exhibited a down-regulation of Villin and tight junction genes, such as E-cadherin and Zonula Occludens-1, when compared to their nontreated counterparts. Furthermore, the transcription level of Lysozyme exhibited an increase, while Mucin 2 showed a decrease in response to LPS, indicating responsiveness to bacterial molecules. Conclusions: Our study provides a layer-by-layer-based co-culture platform to support the prolonged survival of primary IECs and their features, which is important for understanding IEC function in response to the gut microbiota.

Unraveling the Multifaceted Roles of Extracellular Vesicles: Insights into Biology, Pharmacology, and Pharmaceutical Applications for Drug Delivery

Extracellular vesicles (EVs) are nanoparticles released from various cell types that have emerged as powerful new therapeutic option for a variety of diseases. EVs are involved in the transmission of biological signals between cells and in the regulation of a variety of biological processes, highlighting them as potential novel targets/platforms for therapeutics intervention and/or delivery. Therefore, it is necessary to investigate new aspects of EVs' biogenesis, biodistribution, metabolism, and excretion as well as safety/compatibility of both unmodified and engineered EVs upon administration in different pharmaceutical dosage forms and delivery systems. In this review, we summarize the current knowledge of essential physiological and pathological roles of EVs in different organs and organ systems. We provide an overview regarding application of EVs as therapeutic targets, therapeutics, and drug delivery platforms. We also explore various approaches implemented over the years to improve the dosage of specific EV products for different administration routes.

CircZNF609 regulates pulmonary fibrosis via miR-145-5p/KLF4 axis and its translation function

BACKGROUND

Pulmonary fibrosis is a growing clinical problem that develops as a result of abnormal wound healing, leading to breathlessness, pulmonary dysfunction and ultimately death. However, therapeutic options for pulmonary fibrosis are limited because the underlying pathogenesis remains incompletely understood. Circular RNAs, as key regulators in various diseases, remain poorly understood in pulmonary fibrosis induced by silica.

METHODS

We performed studies with fibroblast cell lines and silica-induced mouse pulmonary fibrosis models. The expression of circZNF609, miR-145-5p, and KLF4 was determined by quantitative real-time polymerase chain reaction (qRT-PCR) analysis. RNA immunoprecipitation (RIP) assays and m6A RNA immunoprecipitation assays (MeRIP), Western blotting, immunofluorescence assays, and CCK8 were performed to investigate the role of the circZNF609/miR-145-5p/KLF4 axis and circZNF609-encoded peptides in fibroblast activation.

RESULTS

Our data showed that circZNF609 was downregulated in activated fibroblasts and silica-induced fibrotic mouse lung tissues. Overexpression of circZNF609 could inhibit fibroblast activation induced by transforming growth factor-β1 (TGF-β1). Mechanically, we revealed that circZNF609 regulates pulmonary fibrosis via miR-145-5p/KLF4 axis and circZNF609-encoded peptides. Furthermore, circZNF609 was highly methylated and its expression was controlled by N6-methyladenosine (m6A) modification. Lastly, in vivo studies revealed that overexpression of circZNF609 attenuates silica-induced lung fibrosis in mice.

CONCLUSIONS

Our data indicate that circZNF609 is a critical regulator of fibroblast activation and silica-induced lung fibrosis. The circZNF609 and its derived peptides may represent novel promising targets for the treatment of pulmonary fibrosis.

Single-cell analysis reveals distinct fibroblast plasticity during tenocyte regeneration in zebrafish

Despite their importance in tissue maintenance and repair, fibroblast diversity and plasticity remain poorly understood. Using single-cell RNA sequencing, we uncover distinct sclerotome-derived fibroblast populations in zebrafish, including progenitor-like perivascular/interstitial fibroblasts, and specialized fibroblasts such as tenocytes. To determine fibroblast plasticity in vivo, we develop a laser-induced tendon ablation and regeneration model. Lineage tracing reveals that laser-ablated tenocytes are quickly regenerated by preexisting fibroblasts. By combining single-cell clonal analysis and live imaging, we demonstrate that perivascular/interstitial fibroblasts actively migrate to the injury site, where they proliferate and give rise to new tenocytes. By contrast, perivascular fibroblast-derived pericytes or specialized fibroblasts, including tenocytes, exhibit no regenerative plasticity. Active Hedgehog (Hh) signaling is required for the proliferation of activated fibroblasts to ensure efficient tenocyte regeneration. Together, our work highlights the functional diversity of fibroblasts and establishes perivascular/interstitial fibroblasts as tenocyte progenitors that promote tendon regeneration in a Hh signaling-dependent manner.

Proenkephalin-A secreted by renal proximal tubules functions as a brake in kidney regeneration

Organ regeneration necessitates precise coordination of accelerators and brakes to restore organ function. However, the mechanisms underlying this intricate molecular crosstalk remain elusive. In this study, the level of proenkephalin-A (PENK-A), expressed by renal proximal tubular epithelial cells, decreases significantly with the loss of renal proximal tubules and increased at the termination phase of zebrafish kidney regeneration. Notably, this change contrasts with the role of hydrogen peroxide (H2O2), which acts as an accelerator in kidney regeneration. Through experiments with penka mutants and pharmaceutical treatments, we demonstrate that PENK-A inhibits H2O2 production in a dose-dependent manner, suggesting its involvement in regulating the rate and termination of regeneration. Furthermore, H2O2 influences the expression of tcf21, a vital factor in the formation of renal progenitor cell aggregates, by remodeling H3K4me3 in renal cells. Overall, our findings highlight the regulatory role of PENK-A as a brake in kidney regeneration.

Cellular composition modifies the biological properties and stability of platelet rich plasma membranes for tissue engineering

Scaffolds should provide structural support for tissue regeneration, allowing their gradual biodegradation and interacting with cells and bioactive molecules to promote remodeling. Thus, the scaffold's intrinsic properties affect cellular processes involved in tissue regeneration, including migration, proliferation, differentiation, and protein synthesis. In this sense, due to its biological effect and clinical potential, Platelet Rich Plasma (PRP) fibrin could be considered a successful scaffold. Given the high variability in commercial PRPs formulations, this research focused on assessing the influence of cellular composition on fibrin membrane stability and remodeling cell activity. The stability and biological effect were evaluated at different time points via D-dimer, type I collagen and elastase quantification in culture media conditioned by Plasma Rich in Growth Factors - Fraction 1 (PRGF-F1), Plasma Rich in Growth Factors - Whole Plasma (PRGF-WP) and Leukocyte-rich Platelet Rich Plasma (L-PRP) membranes, and by gingival fibroblast cells seeded on them, respectively. Ultrastructure of PRP membranes was also evaluated. Histological analyses were performed after 5 and 18 days. Additionally, the effect of fibrin membranes on cell proliferation was determined. According to the results, L-PRP fibrin membranes degradation was complete at the end of the study, while PRGF membranes remained practically unchanged. Considering fibroblast behavior, PRGF membranes, in contrast to L-PRP ones, promoted extracellular matrix biosynthesis at the same time as fibrinolysis and enhanced cell proliferation. In conclusion, leukocytes in PRP fibrin membranes drastically reduce scaffold stability and induce behavioral changes in fibroblasts by reducing their proliferation rate and remodeling ability.

Colitis-associated carcinogenesis: crosstalk between tumors, immune cells and gut microbiota

Colorectal cancer (CRC) is the third most common cancer worldwide. One of the main causes of colorectal cancer is inflammatory bowel disease (IBD), which includes ulcerative colitis (UC) and Crohn's disease (CD). Intestinal epithelial cells (IECs), intestinal mesenchymal cells (IMCs), immune cells, and gut microbiota construct the main body of the colon and maintain colon homeostasis. In the development of colitis and colitis-associated carcinogenesis, the damage, disorder or excessive recruitment of different cells such as IECs, IMCs, immune cells and intestinal microbiota play different roles during these processes. This review aims to discuss the various roles of different cells and the crosstalk of these cells in transforming intestinal inflammation to cancer, which provides new therapeutic methods for chemotherapy, targeted therapy, immunotherapy and microbial therapy.

Hybrid 3D-Printed and Electrospun Scaffolds Loaded with Dexamethasone for Soft Tissue Applications

BACKGROUND

To make the regenerative process more effective and efficient, tissue engineering (TE) strategies have been implemented. Three-dimensional scaffolds (electrospun or 3D-printed), due to their suitable designed architecture, offer the proper location of the position of cells, as well as cell adhesion and the deposition of the extracellular matrix. Moreover, the possibility to guarantee a concomitant release of drugs can promote tissue regeneration.

METHODS

A PLA/PCL copolymer was used for the manufacturing of electrospun and hybrid scaffolds (composed of a 3D-printed support coated with electrospun fibers). Dexamethasone was loaded as an anti-inflammatory drug into the electrospun fibers, and the drug release kinetics and scaffold biological behavior were evaluated.

RESULTS

The encapsulation efficiency (EE%) was higher than 80%. DXM embedding into the electrospun fibers resulted in a slowed drug release rate, and a slower release was seen in the hybrid scaffolds. The fibers maintained their nanometric dimensions (less than 800 nm) even after deposition on the 3D-printed supports. Cell adhesion and proliferation was favored in the DXM-loading hybrid scaffolds.

CONCLUSIONS

The hybrid scaffolds that were developed in this study can be optimized as a versatile platform for soft tissue regeneration.

Effects of collagen, chitosan and mixture on fibroblast responses and angiogenic activities in 2D and 3D in vitro models

Despite accumulating evidences have demonstrated the potential of collagen and chitosan on tissue repair, it remains unclear on their combination effects. Here, we examined the regenerative effects of single collagen, chitosan and their mixture on fibroblasts and endothelial cells at cellular levels. The results showed that fibroblast responses, as indicated by high proliferative rate, increased spheroid diameter and migrated area existing from spheroid edge, and decreased wound area, were significantly promoted by either collagen or chitosan stimulation. Similarly, both collagen and chitosan resulted in increased endothelial cell proliferation and migration with accelerated tube-like network formation and upregulated VE-cadherin expression, although collagen strongly provided this effect. While the 1:1 mixture (100:100 μg/mL of chitosan to collagen) treatment caused a reduction in fibroblast viability, the lower ratio of chitosan (1:10 mixture; 10:100 μg/mL) did not produce any impact on both fibroblast and endothelial cell viabilities. The 1:10 mixture also significantly enhanced the additional effects on fibroblast responses and angiogenic activities as shown by higher endothelial growth, proliferation and migration with accelerated capillary-like network formation than those treated with the single substance. Further investigation of signaling proteins found that collagen significantly increased expressions of p-Fak, p-Akt and Cdk5 whereas chitosan upregulated p-Fak and Cdk5 expressions. Comparing to the single treatments, p-Fak, p-Akt and Cdk5 were higher expressed in the 1:10 mixture. These observations indicate that proper collagen-chitosan mixture provides the combination effects on fibroblast responses and angiogenic activities when a high concentration of collagen is used, possibly through Fak/Akt and Cdk5 signaling pathways. Therefore, this study helps to define the clinical use of collagen and chitosan as promising biomaterials for tissue repair.

Dissecting pulmonary fibroblasts heterogeneity in lung development, health and diseases

Lung fibroblasts are the major components in the connective tissue of the pulmonary interstitium and play essential roles in the developing of postnatal lung, synthesizing the extracellular matrix and maintaining the integrity of the lung architecture. Fibroblasts are activated in various disease conditions and exhibit functional heterogeneities according to their origin, spatial location, activated state and microenvironment. In recent years, advances in technology have enabled researchers to identify fibroblast subpopulations in both mouse and human. Here, we discuss pulmonary fibroblast heterogeneity, focusing on the developing, healthy and pathological lung conditions. We firstly review the expression profiles of fibroblasts during lung development, and then consider fibroblast diversity according to different anatomical sites of lung architecture. Subsequently, we discuss fibroblast heterogeneity in genetic lineage. Finally, we focus on how fibroblast heterogeneity may shed light on different pathological lung conditions such as fibrotic diseases, infectious diseases including COVID-19, and lung cancers. We emphasize the importance of comparative studies to illuminate the overlapping characteristics, expression profiles and signaling pathways of the fibroblast subpopulations across disease conditions, a better characterization of the functional complexity rather than the expression of a particular gene may have important therapeutic applications.

Understanding Fibroblast Heterogeneity in Form and Function

Historically believed to be a homogeneous cell type that is often overlooked, fibroblasts are more and more understood to be heterogeneous in nature. Though the mechanisms behind how fibroblasts participate in homeostasis and pathology are just beginning to be understood, these cells are believed to be highly dynamic and play key roles in fibrosis and remodeling. Focusing primarily on fibroblasts within the skin and during wound healing, we describe the field's current understanding of fibroblast heterogeneity in form and function. From differences due to embryonic origins to anatomical variations, we explore the diverse contributions that fibroblasts have in fibrosis and plasticity. Following this, we describe molecular techniques used in the field to provide deeper insights into subpopulations of fibroblasts and their varied roles in complex processes such as wound healing. Limitations to current work are also discussed, with a focus on future directions that investigators are recommended to take in order to gain a deeper understanding of fibroblast biology and to develop potential targets for translational applications in a clinical setting.

Nicotinamide N-methyltransferase mediates lipofibroblast-myofibroblast transition and apoptosis resistance

Metabolism controls cellular phenotype and fate. In this report, we demonstrate that nicotinamide N-methyltransferase (NNMT), a metabolic enzyme that regulates developmental stem cell transitions and tumor progression, is highly expressed in human idiopathic pulmonary fibrosis (IPF) lungs, and is induced by the pro-fibrotic cytokine, transforming growth factor-β1 (TGF-β1) in lung fibroblasts. NNMT silencing reduces the expression of extracellular matrix proteins, both constitutively and in response to TGF-β1. Furthermore, NNMT controls the phenotypic transition from homeostatic, pro-regenerative lipofibroblasts to pro-fibrotic myofibroblasts. This effect of NNMT is mediated, in part, by the downregulation of lipogenic transcription factors, TCF21 and PPARγ, and the induction of a less proliferative but more differentiated myofibroblast phenotype. NNMT confers an apoptosis-resistant phenotype to myofibroblasts that is associated with the downregulation of pro-apoptotic members of the Bcl-2 family, including Bim and PUMA. Together, these studies indicate a critical role for NNMT in the metabolic reprogramming of fibroblasts to a pro-fibrotic and apoptosis-resistant phenotype and support the concept that targeting this enzyme may promote regenerative responses in chronic fibrotic disorders such as IPF.

A vascularized crypt-patterned colon model for high-throughput drug screening and disease modelling

The colon serves as a primary target for pharmaceutical compound screening and disease modelling. To better study colon diseases and develop treatments, engineered in vitro models with colon-specific physiological features are required. Existing colon models lack integration of colonic crypt structures with underlying perfusable vasculature, where vascular-epithelial crosstalk is affected by disease progression. We present a colon epithelium barrier model with vascularized crypts that recapitulates relevant cytokine gradients in both healthy and inflammatory conditions. Using our previously published IFlowPlate384 platform, we initially imprinted crypt topography and populated the patterned scaffold with colon cells. Proliferative colon cells spontaneously localized to the crypt niche and differentiated into epithelial barriers with a tight brush border. Toxicity of the colon cancer drug, capecitabine, was tested and showed a dose-dependent response and recovery from crypt-patterned colon epithelium exclusively. Perfusable microvasculature was then incorporated around the colon crypts followed by treatment with pro-inflammatory TNFα and IFNγ cytokines to simulate inflammatory bowel disease (IBD)-like conditions. We observed in vivo-like stromal basal-to-apical cytokine gradients in tissues with vascularized crypts and gradient reversals upon inflammation. Taken together, we demonstrated crypt topography integrated with underlying perfusable microvasculature has significant value for emulating colon physiology and in advanced disease modelling.

Dual Impact of IGF2 on Alveolar Stem Cell Function during Tobacco-Induced Injury Repair and Development of Pulmonary Emphysema and Cancer

Pulmonary emphysema is a destructive inflammatory disease primarily caused by cigarette smoking (CS). Recovery from CS-induced injury requires proper stem cell (SC) activities with a tightly controlled balance of proliferation and differentiation. Here we show that acute alveolar injury induced by two representative tobacco carcinogens, 4-(methylnitrosamino)-1-(3-pyridyl)-1-butanone and benzo[a]pyrene (N/B), increased IGF2 expression in alveolar type 2 (AT2) cells to promote their SC function and facilitate alveolar regeneration. Autocrine IGF2 signaling upregulated Wnt genes, particularly Wnt3, to stimulate AT2 proliferation and alveolar barrier regeneration after N/B-induced acute injury. In contrast, repetitive N/B exposure provoked sustained IGF2-Wnt signaling through DNMT3A-mediated epigenetic control of IGF2 expression, causing a proliferation/differentiation imbalance in AT2s and development of emphysema and cancer. Hypermethylation of the IGF2 promoter and overexpression of DNMT3A, IGF2, and the Wnt target gene AXIN2 were seen in the lungs of patients with CS-associated emphysema and cancer. Pharmacologic or genetic approaches targeting IGF2-Wnt signaling or DNMT prevented the development of N/B-induced pulmonary diseases. These findings support dual roles of AT2 cells, which can either stimulate alveolar repair or promote emphysema and cancer depending on IGF2 expression levels.

SIGNIFICANCE

IGF2-Wnt signaling plays a key role in AT2-mediated alveolar repair after cigarette smoking-induced injury but also drives pathogenesis of pulmonary emphysema and cancer when hyperactivated.

Application of hydrogel wound dressings in cell therapy-approaches to assessment in vitro

Cell therapy is actively used to treat skin defects, particularly burn lesions. The effectiveness of its application may depend on the appropriate choice of wound dressings used together with any cellular material. The aim of the study was to investigate the interaction of 4 hydrogel dressings used in clinical practice with human cells in an in vitro model to determine if their use in combination with cell therapy is possible. The effect of the dressings on the growth medium was assessed by considering the changes caused in the medium's acid-base equilibrium (pH) and viscosity. Cytotoxicity was determined by applying an MTT-assay and by direct contact methods. Cell adhesion and viability on the dressing surfaces were analyzed using fluorescence microscopy. Proliferative and secretory cell activity were determined concurrently. Characterized human dermal fibroblast cultures were used as the test cultures. Results: The tested dressings interacted differently with the growth medium and the test cultures. 1-day extracts of all dressings had almost no effect on the acid-base balance, but, after 7 days, the pH of the dressing Type 2 extract had sharply acidified. The viscosity of the media under the influence of dressings of Types 2 and 3 had also markedly increased. MTT-assays showed nontoxicity of all the 1-day-incubated dressing extracts, while incubation for 7-days resulted in extracts with evident cytotoxicity, which was reduced upon dilution. Cell adhesion to the surfaces of the dressings differed, being observed occurring on dressings 2 and 3, and to a limited extent on dressing 4. Cells under dressing 1 showed evident proliferative and secretory activity whereas the other dressings impaired either proliferation or secretion processes. These effects indicate that, in general, comprehensive studies including a variety of methodological approaches at the in vitro stage are needed to allow the selection of appropriate dressings if they are to be used in combination with cell therapy to act as cell carriers. Of those investigated, the Type 1 dressing can be recommended as a protective dressing for use after transplantation of cells into a wound defect area by some other method.

CD34+ cell-derived fibroblast-macrophage cross-talk drives limb ischemia recovery through the OSM-ANGPTL signaling axis

CD34⁺ cells improve the perfusion and function of ischemic limbs in humans and mice. However, there is no direct evidence of the differentiation potential and functional role of these cells in the ischemic muscle microenvironment. Here, we combined the single-cell RNA sequencing and genetic lineage tracing technology, then provided exact single-cell atlases of normal and ischemic limb tissues in human and mouse, and consequently found that bone marrow (BM)-derived macrophages with antigen-presenting function migrated to the ischemic site, while resident macrophages underwent apoptosis. The macrophage oncostatin M (OSM) regulatory pathway was specifically turned on by ischemia. Simultaneously, BM CD34⁺-derived proregenerative fibroblasts were recruited to the ischemia niche, where they received macrophage-released OSM and promoted angiopoietin-like protein-associated angiogenesis. These findings provided mechanisms on the cellular events and cell-cell communications during tissue ischemia and regeneration and provided evidence that CD34⁺ cells serve as fibroblast progenitors promoting tissue regeneration.

Bovine Fibroblast-Derived Extracellular Matrix Promotes the Growth and Preserves the Stemness of Bovine Stromal Cells during In Vitro Expansion

Cultivated meat is a fast-growing research field and an industry with great potential to overcome the limitations of traditional meat production. Cultivated meat utilizes cell culture and tissue engineering technologies to culture a vast number of cells in vitro and grow/assemble them into structures mimicking the muscle tissues of livestock animals. Stem cells with self-renewal and lineage-specific differentiation abilities have been considered one of the key cell sources for cultivated meats. However, the extensive in vitro culturing/expansion of stem cells results in a reduction in their abilities to proliferate and differentiate. Extracellular matrix (ECM) has been used as a culturing substrate to support cell expansion for cell-based therapies in regenerative medicine due to its resemblance to the native microenvironment of cells. In this study, the effect of the ECM on the expansion of bovine umbilical cord stromal cells (BUSC) in vitro was evaluated and characterized. BUSCs with multi-lineage differentiation potentials were isolated from bovine placental tissue. Decellularized ECM prepared from a confluent monolayer of bovine fibroblasts (BF) is free of cellular components but contains major ECM proteins such as fibronectin and type I collagen and ECM-associated growth factors. Expansion of BUSC on ECM for three passages (around three weeks) resulted in about 500-fold amplification, while cells were amplified less than 10-fold when cultured on standard tissue culture plates (TCP). Moreover, the presence of ECM reduced the requirement for serum in the culture medium. Importantly, the cells amplified on ECM retained their differentiation abilities better than cells cultured on TCP. The results of our study support the notion that monolayer cell-derived ECM may be a strategy to expand bovine cells in vitro effectively and efficiently.

Ischemia challenged epicardial adipose tissue stem cells-derived extracellular vesicles alter the gene expression of cardiac fibroblasts to cardiomyocyte like phenotype

The present study hypothesizes that the ischemic insults activate epicardial adipose tissue-derived stem cells (EATDS) to secrete extracellular vesicles (EVs) packed with regenerative mediators to alter the gene expression in cardiac fibroblasts (CF). EATDS and CF were isolated from hyperlipidemic microswine and EVs were harvested from control, simulated ischemia (ISC) and ischemia-reperfusion (ISC/R) groups. The in vitro interaction between ISC-EVs and CF resulted in the upregulation of cardiomyocyte-specific transcription factors including GATA4, Nkx2.5, IRX4, and TBX5 in CF and the healing marker αSMA and the downregulation of fibroblast biomarkers such as vimentin, FSP1, and podoplanin and the cardiac biomarkers such as troponin-I and connexin-43. These results suggest a cardiomyocyte-like phenotype as confirmed by immunostaining and Western blot. The LC-MS/MS analysis of ISC-EVs LGALS1, PRDX2, and CCL2 to be the potent protein mediators which are intimately involved in versatile regenerative processes and connected with a diverse array of regenerative genes. Moreover, the LGALS1+, PRDX2+, and CCL2+ EATDS phenotypes were deciphered at single cell resolution revealing corresponding sub-populations with superior healing potential. Overall, the findings unveiled the healing potential of EATDS-derived EVs and sub-populations of regenerative EATDS promising novel translational opportunities in improved cardiac healing following ischemic injury.

Splashed E-box and AP-1 motifs cooperatively drive regeneration response and shape regeneration abilities

Injury triggers a genetic program that induces gene expression for regeneration. Recent studies have identified regeneration-response enhancers (RREs); however, it remains unclear whether a common mechanism operates in these RREs. We identified three RREs from the zebrafish fn1b promoter by searching for conserved sequences within the surrounding genomic regions of regeneration-induced genes and performed a transgenic assay for regeneration response. Two regions contained in the transposons displayed RRE activity when combined with the -0.7 kb fn1b promoter. Another non-transposon element functioned as a stand-alone enhancer in combination with a minimum promoter. By searching for transcription factor-binding motifs and validation by transgenic assays, we revealed that the cooperation of E-box and activator protein 1 motifs is necessary and sufficient for regenerative response. Such RREs respond to variety of tissue injuries, including those in the zebrafish heart and Xenopus limb buds. Our findings suggest that the fidelity of regeneration response is ensured by the two signals evoked by tissue injuries. It is speculated that a large pool of potential enhancers in the genome has helped shape the regenerative capacities during evolution.

The Stockholm Syndrome of Cancer: Fibroblasts as a Powerful Shield against Colorectal Cancer Therapy

Fibroblasts are incredible cells [...].

Current perspectives of residual ridge resorption: Pathological activation of oral barrier osteoclasts

PURPOSE

Tooth extraction is a last resort treatment for resolving pathological complications of dentition induced by infection and injury. Although the extraction wound generally heals uneventfully, resulting in the formation of an edentulous residual ridge, some patients experience long-term and severe residual ridge reduction. The objective of this review was to provide a contemporary understanding of the molecular and cellular mechanisms that may potentially cause edentulous jawbone resorption.

STUDY SELECTION

Clinical, in vivo, and in vitro studies related to the characterization of and cellular and molecular mechanisms leading to residual ridge resorption.

RESULTS

The alveolar processes of the maxillary and mandibular bones uniquely juxtapose the gingival tissue. The gingival oral mucosa is an active barrier tissue that maintains homeostasis of the internal organs through its unique barrier immunity. Tooth extraction not only generates a bony socket but also injures oral barrier tissue. In response to wounding, the alveolar bone socket initiates regeneration and remodeling through coupled bone formation and osteoclastic resorption. Osteoclasts are also found on the external surface of the alveolar bone, interfacing the oral barrier tissue. Osteoclasts in the oral barrier region are not coupled with osteoblastic bone formation and often remain active long after the completion of wound healing, leading to a net decrease in the alveolar bone structure.

CONCLUSIONS

The novel concept of oral barrier osteoclasts may provide important clues for future clinical strategies to maintain residual ridges for successful prosthodontic and restorative therapies.

Myofibroblast depletion reduces kidney cyst growth and fibrosis in autosomal dominant polycystic kidney disease

Autosomal dominant polycystic kidney disease (ADPKD) involves the development and persistent growth of fluid filled kidney cysts. In a recent study, we showed that ADPKD kidney cyst epithelial cells can stimulate the proliferation and differentiation of peri-cystic myofibroblasts. Although dense myofibroblast populations are often found surrounding kidney cysts, their role in cyst enlargement or fibrosis in ADPKD is unclear. To clarify this, we examined the effect of myofibroblast depletion in the Pkd1RC/RC (RC/RC) mouse model of ADPKD. RC/RC;αSMAtk mice that use the ganciclovir-thymidine kinase system to selectively deplete α-smooth muscle actin expressing myofibroblasts were generated. Ganciclovir treatment for four weeks depleted myofibroblasts, reduced kidney fibrosis and preserved kidney function in these mice. Importantly, myofibroblast depletion significantly reduced cyst growth and cyst epithelial cell proliferation in RC/RC;αSMAtk mouse kidneys. Similar ganciclovir treatment did not alter cyst growth or fibrosis in wild-type or RC/RC littermates. In vitro, co-culture with myofibroblasts from the kidneys of patients with ADPKD increased 3D microcyst growth of human ADPKD cyst epithelial cells. Treatment with conditioned culture media from ADPKD kidney myofibroblasts increased microcyst growth and cell proliferation of ADPKD cyst epithelial cells. Further examination of ADPKD myofibroblast conditioned media showed high levels of protease inhibitors including PAI1, TIMP1 and 2, NGAL and TFPI-2, and treatment with recombinant PAI1 and TIMP1 increased ADPKD cyst epithelial cell proliferation in vitro. Thus, our findings show that myofibroblasts directly promote cyst epithelial cell proliferation, cyst growth and fibrosis in ADPKD kidneys, and their targeting could be a novel therapeutic strategy to treat PKD.

Convergence of Biofabrication Technologies and Cell Therapies for Wound Healing

BACKGROUND

Cell therapy holds great promise for cutaneous wound treatment but presents practical and clinical challenges, mainly related to the lack of a supportive and inductive microenvironment for cells after transplantation. Main: This review delineates the challenges and opportunities in cell therapies for acute and chronic wounds and highlights the contribution of biofabricated matrices to skin reconstruction. The complexity of the wound healing process necessitates the development of matrices with properties comparable to the extracellular matrix in the skin for their structure and composition. Over recent years, emerging biofabrication technologies have shown a capacity for creating complex matrices. In cell therapy, multifunctional material-based matrices have benefits in enhancing cell retention and survival, reducing healing time, and preventing infection and cell transplant rejection. Additionally, they can improve the efficacy of cell therapy, owing to their potential to modulate cell behaviors and regulate spatiotemporal patterns of wound healing.

CONCLUSION

The ongoing development of biofabrication technologies promises to deliver material-based matrices that are rich in supportive, phenotype patterning cell niches and are robust enough to provide physical protection for the cells during implantation.

Human gastric fibroblasts ameliorate A20-dependent cell survival in co-cultured gastric epithelial cells infected by Helicobacter pylori

Crosstalk within the gastric epithelium, which is closely in contact with stromal fibroblasts in the gastric mucosa, has a pivotal impact in proliferation, differentiation and transformation of the gastric epithelium. The human pathogen Helicobacter pylori colonises the gastric epithelium and represents a risk factor for gastric pathophysiology. Infection of H. pylori induces the activation of the transcription factor nuclear factor kappa-light-chain-enhancer of activated B cells (NF-κB), which is involved in the pro-inflammatory response but also in cell survival. In co-cultures with human gastric fibroblasts (HGF), we found that apoptotic cell death is reduced in the polarised human gastric cancer cell line NCI-N87 or in gastric mucosoids during H. pylori infection. Interestingly, suppression of apoptotic cell death in NCI-N87 cells involved an enhanced A20 expression regulated by NF-κB activity in response to H. pylori infection. Moreover, A20 acts as an important negative regulator of caspase-8 activity, which was suppressed in NCI-N87 cells during co-culture with gastric fibroblasts. Our results provide evidence for NF-κB-dependent regulation of apoptotic cell death in cellular crosstalk and highlight the protective role of gastric fibroblasts in gastric epithelial cell death during H. pylori infection.

The cellular landscape of the normal kidney allograft: Main players balancing the alloimmune response

Despite recent advances made in short-term outcomes; minimal improvements have been observed in long-term kidney transplantation outcomes. Due to an imbalance between organ transplant availability and patient waiting list, expanding kidney allograft longevity is a critical need in the field. Prior studies have either focused on early ischemic and immunological conditions affecting kidney allografts (e.g., delayed graft function, acute rejection) or late stage chronic injury when interventions are no longer feasible. However, studies characterizing kidney allografts with normal function by its cellular distribution, cell-cell interactions, and associated molecular pathways are lacking. Herein, we used single nuclei RNA-sequencing to uncover the cellular landscape and transcriptome of the normal kidney allograft. We profiled 40,950 nuclei from seven human kidney biopsies (normal native, N = 3; normal allograft, N = 4); normal allograft protocol biopsies were collected ≥15-months post-transplant. A total of 17 distinct cell clusters were identified with proximal tubules (25.70 and 21.01%), distal tubules (15.22 and 18.20%), and endothelial cells (EC) (4.26 and 9.94%) constituting the major cell populations of normal native and normal allograft kidneys, respectively. A large proportion of cycling cells from normal native kidneys were in G1-phase (43.96%) whereas cells from normal allograft were predominantly in S-phase (32.69%). This result suggests that transcriptional differences between normal native and normal allograft biopsies are dependent on the new host environment, immunosuppression, and injury-affliction. In the normal allograft, EC-specific genes upregulated metabolism, the immune response, and cellular growth, emphasizing their role in maintaining homeostasis during the ongoing alloreactive stress response. Immune cells, including B (2.81%), macrophages (24.96%), monocytes (15.29%), natural killer (NK) (12.83%), neutrophils (8.44%), and T cells (14.41%, were increased in normal allografts despite lack of histological or clinical evidence of acute rejection. Phenotypic characterization of immune cell markers supported lymphocyte activation and proinflammatory cytokines signaling pathways (i.e., IL-15, IL-32). The activation of B, NK, and T cells reveals potential immune cells underlying subclinical inflammation and repair. These single nuclei analyses provide novel insights into kidney and immune cell associated signaling pathways that portray kidney grafts with normal allograft function beyond 2-years post-transplant, revealing a novel perspective in understanding long-term allograft graft survival.