CD44-dependent inflammation, fibrogenesis, and collagenolysis regulates extracellular matrix remodeling and tensile strength during cutaneous wound healing

Semaphorin 3E-Plexin-D1 Pathway Downstream of the Luteinizing Hormone Surge Regulates Ovulation, Granulosa Cell Luteinization, and Ovarian Angiogenesis in Mice

Ovulation is induced by the luteinizing hormone (LH) surge and accompanied by granulosa cell luteinization and ovarian angiogenesis. Semaphorin 3E (Sema3E)-Plexin-D1 pathway regulates angiogenesis in other tissues, but its role in the ovary is unknown. Evidence indicates that Sema3E-Plexin-D1 pathway plays an important role in the mouse ovary. The expression of Sema3E and its receptor, Plexin-D1, is dynamically regulated in the mouse ovary downstream of the LH surge. This regulation requires the modulation of chromatin accessibility by CCAAT/enhancer-binding proteins α and β. Intraovarian injection of recombinant Sema3E results in reduced ovulation, impaired corpus luteum formation, and aberrant ovarian angiogenesis. These in vivo physiological abnormalities are consistent with altered expression of genes regulating these processes, and with data from in vitro cultured granulosa cells and ovarian stromal tissues treated with Sema3E or neutralizing antibody of Plexin-D1. The findings pinpoint Sema3E-Plexin-D1 pathway as a potential therapeutic target for fertility and infertility management.

Deficiency of Aging-Related Gene Chitinase-Like 4 Impairs Olfactory Epithelium Homeostasis

Mammalian olfactory epithelium (OE) undergoes consistent self-renewal throughout life. In OE homeostasis, globose basal cells (GBCs) contribute to the generation of olfactory sensory neurons (OSNs) to replace old ones. Chitinase-like 4 (Chil4), a chitinase-like protein expressed in supporting cells, plays a critical role in OE regeneration, while its role in tissue homeostasis is still elusive. Here, we found that Chil4 is upregulated in the aged OE. Deletion of Chil4 leads to a reduction in the number of GBCs and immature OSNs (iOSNs). Chil4-/- GBCs show attenuation in cell cycle progression and an aberrant expression pattern of cell-cycle-related genes such as Cdk1. Chil4 deletion causes loss of a specific subcluster of GAP43+ iOSNs expressing Cebpb, Nqo1 and low level of mature OSN (mOSN) marker Stoml3 (iOSN_CeStLNq), potentially suggesting a transitional state between immature and mature neurons. Chil4 knockout induces inflammatory activation in Iba1+ microglia (MG)-like cells in the OE. Chil4 downregulation in aged organoids reduced the number of mature sensory neurons, suggesting a necessary role of Chil4 in maintaining neuronal generation in the aged OE. Collectively, these observations reveal a previously unidentified function of Chil4, establishing the cellular mechanism underlying OE homeostasis.

Identifying Immunomodulatory Subpopulations of Adipose Stromal Vascular Fraction and Stem/Stromal Cells Through Single-Cell Transcriptomics and Bulk Proteomics

A primary therapeutic characteristic of mesenchymal stem/stromal cells (MSCs) is their immunomodulatory activity. Adipose-derived stem/stromal cells (ASCs) are an abundant and easily isolated source of MSCs shown to have high immunosuppressive activity, making them attractive for therapy. Understanding the heterogeneous immunomodulatory potential of ASCs within the stromal vascular fraction (SVF) of adipose tissue could better inform treatment strategies. In this study, we integrate single-cell RNA sequencing (scRNA seq) with bulk proteomics to characterize subpopulations of SVF-derived ASCs that are phenotypically similar to cytokine-licensed, cultured ASCs. To better define the licensing process, we present scRNA seq and bulk proteomics data of cultured (P2) ASCs exposed to inflammatory cytokines, showing enrichment of pathways related to inflammation and apoptosis that positively correlate to the cytokine-mediated, trajectory-derived pseudotime. Using the Scissor algorithm, we integrate the proteomics data with uncultured (P0) SVF scRNA seq data, identifying an ASC subpopulation that is phenotypically like the cytokine-stimulated ASCs (Scissor-positive). Interactome analysis identifies Scissor-positive ASCs as stress adaptive immune regulators that function through IL6 and broad SEMA4 interactions and higher Visfatin signaling, while Scissor-negative ASCs show strong signatures of ECM remodeling through FN1 and immunosuppression through THY1 and MIF signaling. Our multimodal, integrative approach enabled identification of previously unidentified, distinct ASC subpopulations with differing immunomodulatory phenotypes that are present in, and can potentially be selected from, P0 SVF ASCs.

Imaging methods to monitor and quantify cell differentiation

The transition of a cell from a stem to a differentiated state involves an interrelated and complex series of events. These events include dynamic changes in cellular nucleic acid and protein content that are mediated by both intrinsic and extrinsic factors which ultimately lead to differentiation into specific lineage. Quantifying the parameters associated with differentiation and their changes under different conditions would not only allow for a better understanding of this process but also would enable the development of approaches that control differentiation. Here, we describe processes associated with the differentiation of two types of cultured cells, neurons and fibroblasts, and the tools to follow changes in real time. Specifically, we discuss methods to the identify cell lineage, changes in morphology, shifts in specific mRNA and miRNA levels as well as the changes in protein localization, interactions and assemblies that accompany differentiation.

Single cell multiomics reveals drivers of metabolic dysfunction-associated steatohepatitis

Metabolic dysfunction-associated steatotic liver disease (MASLD) has limited treatments, and cell type-specific regulatory networks driving MASLD represent therapeutic avenues. We assayed five transcriptomic and epigenomic modalities in 2.4M cells from 86 livers across MASLD stages. Integrating modalities increased annotation of the genome in liver cell types several-fold over previous catalogs. We identified cell type regulatory networks of MASLD progression, including distinct hepatocyte networks driving MASL and mild and severe fibrosis MASH. Our single cell atlas annotated 88% of MASH-associated loci, including a third affecting hepatocyte regulation which we linked to distal target genes. Finally, we characterized hepatocyte heterogeneity, including MASH-enriched populations with altered repression, localization, and signaling. Overall, our results provide high-resolution maps of liver cell types and revealed novel targets for anti-MASH therapy.

Hyaluronic Acid-Based Therapy for Alleviating Early Lipid Peroxidation in Peripheral Nerve Compression Injury Repair

BACKGROUND

Peripheral nerve injuries compromise sensory and motor functions, severely affecting patients' quality of life. Early lipid peroxidation drives oxidative stress, disrupting the regenerative microenvironment. Hyaluronic acid (HA), an essential extracellular matrix component, shows promise in mitigating oxidative damage and fostering repair.

METHODS

In a rat sciatic nerve crush model, HA hydrogel was applied to enhance retention at the injury site. Transcriptomic analysis at 24 hours postinjury identified key pathways. In vitro assays examined HA's protective effects on Schwann cells against lipid peroxidation and oxidative stress. In vivo, HA hydrogel was administered immediately (0 hour) postcrush, followed by 4-methylumbelliferone-induced inhibition of endogenous HA synthesis and exogenous HA supplementation to clarify HA's role.

RESULTS

HA treatment reduced early lipid peroxidation, upregulated glutathione metabolism, and stimulated extracellular matrix receptor interactions, notably elevating CD44 expression. In vitro, HA lowered oxidative stress and maintained Schwann cell viability. In vivo, early HA intervention mitigated muscle atrophy, preserved myelin sheaths, and improved Sciatic Functional Index scores compared to delayed or untreated controls. Inhibiting endogenous HA synthesis impaired recovery, which was partially reversed by exogenous HA.

CONCLUSIONS

Early HA intervention modulates lipid peroxidation and oxidative stress via the HA/CD44 axis, establishing a supportive microenvironment for peripheral nerve regeneration and functional recovery. These findings underscore the potential of HA-based strategies to curb early lipid peroxidation, thereby expediting nerve repair and accelerating regeneration.

pH-responsive photothermal effect and heterojunction formation for tumor-specific pyroelectrodynamic and nanozyme-catalyzed starvation therapy

Pyroelectrodynamic therapy (PEDT) integrates photothermal ablation and catalytic generation of reactive oxygen species (ROS), yet tumor-specific PEDT remains unexplored. Herein, pyroelectric tetragonal BaTiO3 (tBT) nanoparticles (NPs) were capped with polyaniline (PANI) via a Pickering emulsion-masking method, followed by in situ deposition of MnO2 nanodots on PANI caps to synthesize Janus tBT@PANI-MnO2 NPs. PANI emeraldine salts (PANI-ES) at pH 6.5 display strong near-infrared II (NIR-II) absorption and 4.67-fold higher photothermal conversion efficiency than that of PANI emeraldine base at pH 7.4. MnO2 nanodots exhibit self-propagating glucose oxidase (GOx), peroxidase (POD), and catalase (CAT) catalytic activities, remodeling the tumor microenvironment and enhancing PTT and PEDT efficacy. Heterojunction formation with PANI-ES generates 1.63-fold higher pyroelectric potentials compared to pristine tBT NPs. The pyroelectric field selectively alters tumor cell membrane potential and, along with the self-propelled motion by asymmetrical thermophoresis from the Janus structure, promotes cellular uptake of NPs. Tumor accumulation of NPs increases 3.2 folds with broad intratumoral distributions of NPs and ROS. Synergistic toxicities to tumor cells arise from PANI-mediated photothermal effect, ROS generation from tBT-PANI heterojunctions, and MnO2 nanozymes-catalyzed glucose depletion. Integration of PEDT, mild PTT and MnO2-catalyzed starvation therapy completely inhibits tumor growth, extends animal survival, elevated intratumoral O2 levels, and suppressed adenosine triphosphate productions. Thus, this Janus NP design represents the first attempt to develop pH-responsive heterojunctions and enables tumor-specific PTT, PEDT and nanozyme-catalyzed starvation therapy. STATEMENT OF SIGNIFICANCE: Although phototherapy achieves light localization for tumor suppression, inevitable toxicities usually occur when light penetrates healthy tissues with accumulation of photoactive agents. Extensive efforts have been dedicated to exploring tumor microenvironment-responsive drug delivery systems, aiming to enhance tumor-targeting efficiency and treatment selectivity of anticancer agents. However, to date, no efforts have been made to develop a method that can achieve tumor-specific temperature elevation and pyroelectrodynamic therapy while simultaneously minimizing exposure to normal tissues. To address these challenges, a concise strategy is proposed to generate pyroelectric heterojunctions in response to the slightly acidic tumor microenvironment, taking advantages of reversible protonation and deprotonation properties of polyaniline. The tumor-specific conversion into polyaniline emeraldine salts triggers strong NIR-II absorptions and pyroelectric effect, and the self-propagated catalytic reactions of MnO2 nanozymes reinforce photothermal, pyroelectrodynamic and starvation therapies of tumors.

OTUD1 delays wound healing by regulating endothelial function and angiogenesis in diabetic mice

INTRODUCTION

Diabetic non-healing wounds represent a major complication of diabetes, primarily due to impaired angiogenesis. Ovarian tumor deubiquitinase 1 (OTUD1), a deubiquitinase, has been implicated in vascular pathophysiology; however, its role in endothelial dysfunction and angiogenesis during diabetic wound healing is still poorly understood.

OBJECTIVES

This study explores whether OTUD1 influences angiogenesis and its underlying mechanisms.

METHODS

We developed OTUD1 knockout mice and induced type 1 and type 2 diabetes mellitus (T1DM and T2DM) by administering streptozotocin (STZ) alone or in combination with a high-fat diet (HFD), respectively. Human umbilical vein endothelial cells (HUVECs) incubated with high glucose and palmitic acid (HG + PA) were utilized to imitate hyperglycemia-induced endothelial dysfunction in vitro. Mass spectrometry combined with immunoprecipitation analysis was used to analyze the interacting proteins of OTUD1. Moreover, we developed endothelial-specific OTUD1 knockdown db/db mice using an adeno-associated virus serotype 2/BI30 (AAV2/BI30) vector.

RESULTS

Increased OTUD1 expressions were observed both in diabetic wound tissues and in HUVECs treated with HG + PA. OTUD1 deficiency promoted angiogenesis and fibrosis in wound tissues of T1DM and T2DM mice and alleviated HG + PA-induced endothelial migration inhibition, tube formation impairment, and oxidative stress in HUVECs. Mechanistically, OTUD1 directly interacted with β-catenin, reducing its K63-linked ubiquitination at residues K496, K508, and K625 via its catalytic site C320. This modification facilitated β-catenin phosphorylation, restricted its nuclear translocation, and downregulated the expression of angiogenesis-related factors. Finally, pharmacological inhibition of β-catenin reversed the improvement of delayed wound healing induced by OTUD1 knockdown in db/db mice.

CONCLUSION

These findings elucidate the OTUD1-β-catenin pathway's role in endothelial dysfunction-associated angiogenesis and suggest OTUD1 as a promising therapeutic target for diabetic non-healing wounds.

Collagen-Based Wound Dressings: Innovations, Mechanisms, and Clinical Applications

Collagen-based wound dressings have developed as an essential component of contemporary wound care, utilizing collagen's inherent properties to promote healing. This review thoroughly analyzes collagen dressing advances, examining different formulations such as hydrogels, films, and foams that enhance wound care. The important processes by which collagen promotes healing (e.g., promoting angiogenesis, encouraging cell proliferation, and offering structural support) are discussed to clarify its function in tissue regeneration. The effectiveness and adaptability of collagen dressings are demonstrated via clinical applications investigated in acute and chronic wounds. Additionally, commercially accessible collagen-based skin healing treatments are discussed, demonstrating their practical use in healthcare settings. Despite the progress, the study discusses the obstacles and restrictions encountered in producing and adopting collagen-based dressings, such as the difficulties of manufacturing and financial concerns. Finally, the current landscape's insights indicate future research possibilities for collagen dressing optimization, bioactive agent integration, and overcoming existing constraints. This analysis highlights the potential of collagen-based innovations to improve wound treatment methods and patient care.

M2 macrophages regulate nucleus pulposus cell extracellular matrix synthesis through the OPN-CD44 axis in intervertebral disc degeneration

OBJECTIVE

Macrophages play a crucial role in various physiological processes. In intervertebral disc degeneration (IDD), macrophage infiltration has been observed in human intervertebral disc (IVD) specimens, but how macrophages influence IDD remains unclear.

METHODS

According to the single-cell transcriptome expression profiles from GSE165722, we verified the infiltration of macrophages in IDD and the possible interaction between infiltrated macrophages and nucleus pulposus cells (NPCs). The expression of macrophage-associated markers was verified in specimens of human nucleus pulposus, lumbar spinal instability mice and annulus fibrosus puncture mice. By treating NPCs cocultured with M2 macrophages with osteopontin (OPN) neutralization antibody and siCD44, we demonstrated that both in vitro and in vivo macrophages regulated IDD through the OPN-CD44 axis. Using transforming growth factor beta 1 and siCD44 treatment, we verified that CD44 regulated the pSMAD2/3 pathway.

RESULTS

IDD engaged macrophage infiltration, mainly gathered in the endplate, and induced macrophage M2 polarization. Infiltrated macrophages showed high-level expression of OPN, and NPCs showed upregulated CD44. Depletion of macrophages significantly decreased the expression of OPN and CD44 in degenerative IVD, concurrently exacerbating IDD. The co-culture of macrophages and NPCs in vitro demonstrated that the conditioned media from NPCs induced macrophage M2 polarization. Further, M2 macrophages rescued NPCs extracellular matrix (ECM) phenotype through the OPN-CD44 axis, by regulating pSMAD2/3 nuclear translocation.

CONCLUSIONS

Our findings suggest that macrophages regulate NPC ECM expression in IDD through the OPN-CD44 axis, emphasizing the therapeutic potential of targeting macrophages and the OPN-CD44 axis for IDD prevention and treatment.

CD44 and Its Role in Solid Cancers - A Review: From Tumor Progression to Prognosis and Targeted Therapy

Cluster of differentiation 44 (CD44) is a transmembrane protein expressed in normal cells but overexpressed in several types of cancer. CD44 plays a major role in tumor progression, both locally and systemically, by direct interaction with the extracellular matrix, inducing tissue remodeling, activation of different cellular pathways, such as Akt or mechanistic target of rapamycin (mTOR), and stimulation of angiogenesis. As a prognostic marker, CD44 has been identified as a major player in cancer stem cells (CSCs). CSCs with a CD44 phenotype are associated with chemoresistance, alone or in combination with other CSC markers, such as CD24 or aldehyde dehydrogenase 1 (ALDH1), and may be used for patient stratification. In the therapy setting, CD44 has been explored as a viable target, directly or indirectly. It has revealed promising potential, paving the way for its future use in the clinical setting. Immunohistochemistry effectively detects CD44 overexpression, enabling patients to be accurately selected for surgery and targeted anti-CD44 therapies. In this review, we highlight the properties of CD44, its expression in normal and tumoral tissues through immunohistochemistry and potential treatment options. We also discuss the clinical significance of this marker and its added value in therapeutic decision-making.

Sustained-Release H2S Nanospheres Regulate the Inflammatory Microenvironment of Wounds, Promote Angiogenesis and Collagen Deposition, and Accelerate Diabetic Wound Healing

Diabetic wounds are blocked in the inflammatory stage, growth factors are degraded, and blood vessels are difficult to regenerate, leading to continuous necrosis and nonhealing of the wound. Hydrogen sulfide (H2S) plays an important role in the pathophysiological process of wound healing and has a long history of treating skin diseases. Although the sulfide salt solution is the preferred donor of exogenous H2S, its rapid release rate, excess production, and difficulty in accurately controlling the dose limit its use. Herein, we developed H2S sustained-release nanospheres NaHS@MS@LP for the treatment of diabetic wounds. NaHS@MS@LP nanosphere was composed of a NaHS-loaded mesoporous silicon core and a DSPE-PEG liposome outer membrane. When NaHS@MS@LP nanospheres were used to treat the wound of diabetic rats, mesoporous silicon was delivered into the cells and the loaded NaHS slowly released H2S through hydrolysis, participating in all stages of wound healing. In conclusion, NaHS@MS@LP nanospheres regulated the inflammatory microenvironment of wound skin by inducing the transformation of macrophages into M2 type and promoted angiogenesis and collagen deposition to accelerate wound healing in diabetic rats. Our findings provide strategies for the treatment of chronic wounds, including but not limited to diabetic wounds.

Cell and transcriptomic diversity of infrapatellar fat pad during knee osteoarthritis

OBJECTIVES

In this study, we employ a multiomic approach to identify major cell types and subsets, and their transcriptomic profiles within the infrapatellar fat pad (IFP), and to determine differences in the IFP based on knee osteoarthritis (KOA), sex and obesity status.

METHODS

Single-nucleus RNA sequencing of 82 924 nuclei from 21 IFPs (n=6 healthy control and n=15 KOA donors), spatial transcriptomics and bioinformatic analyses were used to identify contributions of the IFP to KOA. We mapped cell subclusters from other white adipose tissues using publicly available literature. The diversity of fibroblasts within the IFP was investigated by bioinformatic analyses, comparing by KOA, sex and obesity status. Metabolomics was used to further explore differences in fibroblasts by obesity status.

RESULTS

We identified multiple subclusters of fibroblasts, macrophages, adipocytes and endothelial cells with unique transcriptomic profiles. Using spatial transcriptomics, we resolved distributions of cell types and their transcriptomic profiles and computationally identified putative cell-cell communication networks. Furthermore, we identified transcriptomic differences in fibroblasts from KOA versus healthy control donor IFPs, female versus male KOA-IFPs and obese versus normal body mass index (BMI) KOA-IFPs. Finally, using metabolomics, we defined differences in metabolite levels in supernatants of naïve, profibrotic stimuli-treated and proinflammatory stimuli-treated fibroblasts from obese compared to normal BMI KOA-IFPs.

CONCLUSIONS

Overall, by employing a multiomic approach, this study provides the first comprehensive map of the cellular and transcriptomic diversity of human IFP and identifies IFP fibroblasts as key cells contributing to transcriptomic and metabolic differences related to KOA disease, sex or obesity.

Safety and Performance of RHA4 in the Midface Using the Multilayering Technique: Preclinical and Clinical Evidence

Background

Resilient hyaluronic acid (RHA) fillers are used to treat dynamic wrinkles or provide tissue lifting in facial aesthetics. This study explored the biological, biomechanical, and clinical safety and performance of RHA4, a volumizing hyaluronic acid filler tailored for tissue support in dynamic facial areas, upon interaction with human subcutaneous adipose tissue (AT).

Methods

RHA4 underwent cytocompatibility testing with human fibroblasts and adipose stem cells. A 1-year rat in vivo implantation study tracked tissue integration, local effects, and filler degradation. Biomechanical tests assessed RHA4's impact on subcutaneous AT mechanics. Clinical outcomes, safety, injection volumes, and techniques were evaluated in 35 patients, treated in midface deep and superficial fat compartments via a multilayering methodology. Dynamic outcomes and 2-year follow-up of RHA4 in the midface using multilayer treatments were described.

Results

RHA4 demonstrated excellent biocompatibility and tissue integration both in vitro and in vivo, exhibiting minimal local inflammation and rapid collagen bundle formation within the filler. It integrated gradually over time and was well tolerated, allowing for increased extracellular matrix presence, neovascularization, denser collagen deposition, and AT growth. Ex vivo, RHA4 did not impede fat motion biomechanics but visibly lifted the tissue. Clinically, RHA4 proved safe and effective for lifting both deep and superficial fat compartments in the midface without affecting facial expressiveness.

Conclusions

Preclinical and clinical evidence confirmed that RHA4 is a versatile filler capable of lifting tissue efficiently, whether deep or superficial, particularly through the multilayering treatment approach. Importantly, RHA4 preserves AT biomechanics, adapts to the dynamism of the face, and ensures natural-looking outcomes.

The bronchoalveolar lavage fluid CD44 as a marker for pulmonary fibrosis in diffuse parenchymal lung diseases

Introduction

Diffuse parenchymal lung diseases (DPLD) cover heterogeneous types of lung disorders. Among many pathological phenotypes, pulmonary fibrosis is the most devastating and represents a characteristic sign of idiopathic pulmonary fibrosis (IPF). Despite a poor prognosis brought by pulmonary fibrosis, there are no specific diagnostic biomarkers for the initial development of this fatal condition. The major hallmark of lung fibrosis is uncontrolled activation of lung fibroblasts to myofibroblasts associated with extracellular matrix deposition and the loss of both lung structure and function.

Methods

Here, we used this peculiar feature in order to identify specific biomarkers of pulmonary fibrosis in bronchoalveolar lavage fluids (BALF). The primary MRC-5 human fibroblasts were activated with BALF collected from patients with clinically diagnosed lung fibrosis; the activated fibroblasts were then washed rigorously, and further incubated to allow secretion. Afterwards, the secretomes were analysed by mass spectrometry.

Results

In this way, the CD44 protein was identified; consequently, BALF of all DPLD patients were positively tested for the presence of CD44 by ELISA. Finally, biochemical and biophysical characterizations revealed an exosomal origin of CD44. Receiver operating characteristics curve analysis confirmed CD44 in BALF as a specific and reliable biomarker of IPF and other types of DPLD accompanied with pulmonary fibrosis.

A Vaccine Against Fibroblast Activation Protein Improves Murine Cardiac Fibrosis by Preventing the Accumulation of Myofibroblasts

BACKGROUND

Myofibroblasts are primary cells involved in chronic response-induced cardiac fibrosis. Fibroblast activation protein (FAP) is a relatively specific marker of activated myofibroblasts and a potential target molecule. This study aimed to clarify whether a vaccine targeting FAP could eliminate myofibroblasts in chronic cardiac stress model mice and reduce cardiac fibrosis.

METHODS

We coadministered a FAP peptide vaccine with a cytosine-phosphate-guanine (CpG) K3 oligonucleotide adjuvant to male C57/BL6J mice and confirmed an elevation in the anti-FAP antibody titer. After continuous angiotensin II and phenylephrine administration for 28 days, we evaluated the degree of cardiac fibrosis and the number of myofibroblasts in cardiac tissues.

RESULTS

We found that cardiac fibrosis was significantly decreased in the FAP-vaccinated mice compared with the angiotensin II and phenylephrine control mice (3.45±1.11% versus 8.62±4.79%; P=4.59×10-3) and that the accumulation of FAP-positive cells was also significantly decreased, as indicated by FAP immunohistochemical staining (4077±1746 versus 7327±1741 cells/mm2; FAP vaccine versus angiotensin II and phenylephrine control; P=6.67×10-3). No systemic or organ-specific inflammation due to antibody-dependent cell cytotoxicity induced by the FAP vaccine was observed. Although the transient activation of myofibroblasts has an important role in maintaining the structural robustness in the process of tissue repair, the FAP vaccine showed no adverse effects in myocardial infarction and skin injury models.

CONCLUSIONS

Our study demonstrates the FAP vaccine can be a therapeutic tool for cardiac fibrosis.

CD44/Integrin β1 Association Drives Fast Motility on Hyaluronic Acid Substrates

In addition to proteins such as collagen (Col) and fibronectin, the extracellular matrix (ECM) is enriched with bulky proteoglycan molecules such as hyaluronic acid (HA). However, how ECM proteins and proteoglycans collectively regulate cellular processes has not been adequately explored. Here, we address this question by studying cytoskeletal and focal adhesion organization and dynamics on cells cultured on polyacrylamide hydrogels functionalized with Col, HA and a combination of Col and HA (Col/HA). We show that fastest migration on HA substrates is attributed to the presence of smaller and weaker focal adhesions. Integrinβ $\beta $ 1 co-localization and its association with CD44-which is the receptor for HA, and insensitivity of cell spreading to RGD on HA substrates suggests that focal adhesions on HA substrates are formed via integrin association with HA bound CD44. Consistent with this, adhesion formation and cell motility were inhibited when CD44 was knocked out. Collectively, our results suggest that association of integrinβ $\beta $ 1 with CD44 drives fast motility on HA substrates.

How to Fabricate Hyaluronic Acid for Ocular Drug Delivery

This review aims to examine existing research on the development of ocular drug delivery devices utilizing hyaluronic acid (HA). Renowned for its exceptional biocompatibility, viscoelastic properties, and ability to enhance drug bioavailability, HA is a naturally occurring biopolymer. The review discussed specific mechanisms by which HA enhances drug delivery, including prolonging drug residence time on ocular surfaces, facilitating controlled drug release, and improving drug penetration through ocular tissues. By focusing on these unique functionalities, this review highlights the potential of HA-based systems to revolutionize ocular treatment. Various fabrication techniques for HA-based ocular drug delivery systems, including hydrogels, nanoparticles, and microneedles, are discussed, highlighting their respective advantages and limitations. Additionally, this review explores the clinical applications of HA-based devices in treating a range of ocular diseases, such as dry eye syndrome, glaucoma, retinal disorders, and ocular infections. By comparing the efficacy and safety profiles of these devices with traditional ocular drug delivery methods, this review aims to provide a comprehensive understanding of the potential benefits and challenges associated with HA-based systems. Moreover, this review discusses current limitations and future directions in the field, such as the need for standardized fabrication protocols, long-term biocompatibility studies, and large-scale clinical trials. The insights and advancements presented in this review aim to guide future research and development efforts, ultimately enhancing the effectiveness of ocular drug delivery and improving patient outcomes.

An Update on Molecular Mechanisms of Scarring-A Narrative Review

Fibroblasts, the principal cellular mediators of connective tissue remodeling, play a crucial role in the formation of physiological and pathological scars. Understanding the intricate interplay between fibroblasts and other cellular and molecular components is essential for elucidating the underlying mechanisms driving scar formation. Hypertrophic scars, keloids and atrophic scars arise from dysregulated wound healing processes characterized by persistent inflammation, aberrant collagen deposition, and impaired extracellular matrix remodeling. Fibroblasts play a central role in the pathogenesis of such pathological scars, driving aberrant extracellular matrix remodeling, subsequently contributing to the formation of raised or depressed fibrotic lesions. The investigation of complex interactions between fibroblasts and the microenvironment is crucial for developing targeted therapeutic interventions aimed at modulating fibroblast activity and improving clinical outcomes in patients with pathological scars. Further research into the molecular pathways governing fibroblast behavior and their heterogeneity holds promise for advancing scar management strategies. This narrative review was performed to shed light on the mechanisms behind scar formation, with a special focus on the role of fibroblasts in the formation of different types of scars, providing insights into the pathophysiology of these conditions. Through the analysis of current knowledge, this review seeks to identify the key cellular and molecular mechanisms involved in fibroblast activation, collagen synthesis, and extracellular matrix remodeling in hypertrophic scar, keloid, or atrophic scar formation.

Chondroitin sulfate functionalized nanozymes inhibit the inflammation feedback loop for enhanced atherosclerosis therapy by regulating intercellular crosstalk

In the inflammatory microenvironment of atherosclerotic plaques, metabolic dysregulation of superoxide anion (O2-) and hydrogen peroxide (H2O2) leads to the activation of feedback mechanisms involving IL-1β, TNF-α, and MCP-1, which triggers inflammatory cascades between macrophages and vascular smooth muscle cells (VSMCs) in atherosclerosis (AS). To address this, a chondroitin sulfate (CS)-functionalized dual-targeted engineered nanozyme, CS-Lip/PB@Rap, was developed by encapsulating mesoporous Prussian blue nanoparticles (PBs) loaded with rapamycin (Rap) within CS-modified liposomes. CS functionalization endowed CS-Lip/PB@Rap with a specific targeting ability for CD44 receptors, thus enabling targeted delivery to inflammatory macrophages and VSMCs. Moreover, its enhanced multiple enzyme-like activities effectively modulated the imbalance of oxidative stress. The underlying mechanism of crosstalk regulation by these engineered nanozymes may inhibit the NF-κB pathway by restoring normal metabolism of O2- and H2O2, thereby blocking the TNF-α, IL-1β, and MCP-1 feedback loops between macrophages and VSMCs. This process reduced the production of inflammatory macrophages and inhibited the VSMC transformation from a contractile phenotype to a synthetic phenotype, preventing the formation of fibrous caps. Furthermore, the elimination of oxidative stress could decrease the production of oxygenized low-density lipoprotein (ox-LDL), which inhibited the formation of foam cells and alleviated the atherogenic progression.

Commercial Silver-Based Dressings: In Vitro and Clinical Studies in Treatment of Chronic and Burn Wounds

Chronic wounds are a major health problem because of delayed healing, causing hardships for the patient. The infection present in these wounds plays a role in delayed wound healing. Silver wound dressings have been used for decades, beginning in the 1960s with silver sulfadiazine for infection prevention for burn wounds. Since that time, there has been a large number of commercial silver dressings that have obtained FDA clearance. In this review, we examine the literature involving in vitro and in vivo (both animal and human clinical) studies with commercial silver dressings and attempt to glean the important characteristics of these dressings in treating infected wounds. The primary presentation of the literature is in the form of detailed tables. The narrative part of the review focuses on the different types of silver dressings, including the supporting matrix, the release characteristics of the silver into the surroundings, and their toxicity. Though there are many clinical studies of chronic and burn wounds using silver dressings that we discuss, it is difficult to compare the performances of the dressings directly because of the differences in the study protocols. We conclude that silver dressings can assist in wound healing, although it is difficult to provide general treatment guidelines. From a wound dressing point of view, future studies will need to focus on new delivery systems for silver, as well as the type of matrix in which the silver is deposited. Clearly, adding other actives to enhance the antimicrobial activity, including the disruption of mature biofilms is of interest. From a clinical point of view, the focus needs to be on the wound healing characteristics, and thus randomized control trials will provide more confidence in the results. The application of different wound dressings for specific wounds needs to be clarified, along with the application protocols. It is most likely that no single silver-based dressing can be used for all wounds.

Cyanoacrylate Adhesives for Cutaneous Wound Closure

Cyanoacrylate-based adhesives are widely used in wound closure, providing good cosmetic results and little discomfort. However, reports in the literature are found about negative effects that include the release of cytotoxic chemicals during biodegradation. In this study, we sought to evaluate and compare the effectiveness of four cyanoacrylate-based adhesives on the closure of skin incisions in Rattus norvegicus. The animals (n = 140) were divided into five groups of 28 animals each according to the wound closure technique: G1 and G2 (n-2-ethyl-cyanoacrylate); G3 (n-2-butyl-cyanoacrylate); G4 (n-2-octyl-cyanoacrylate); and G5 (5 nylon stitches). Midline incisions measuring 5.0 cm in length were created and closed using the different materials evaluated, and on D3, D7, D14, and D21, tensiometric and histopathological analyses were performed. Shorter wound closure and adhesion times were observed in G4 animals. At D3 and D7, G5 presented greater tensiometric resistance in the animals of G5, with a decrease in D14 and D21 compared to the other groups. On the other hand, the wounds of G3 and G4 were more resistant in D14 and D21, reaching maximum resistance values. Polymorphonuclear and mononuclear cells are more prevalent and more granulation tissue was observed in G5. The deposition of type III collagen was more evident in G5, whilst there was no difference in the amount of type I collagen in any of the groups treated with cyanoacrylate adhesives. Larger areas stained positive for VEGF-α in G2 and smaller areas in G4, with peaks at D7 and D14. In general, cyanoacrylate adhesives cause less intense inflammatory reactions, resulting in shorter healing times when compared to nylon sutures.

Single-Cell WGCNA Combined with Transcriptome Sequencing to Study the Molecular Mechanisms of Inflammation-Related Ferroptosis in Myocardial Ischemia-Reperfusion Injury

Purpose

Myocardial ischemia-reperfusion injury (MIRI) is characterized by inflammation and ferroptosis, but the precise mechanisms remain unknown. This study used single-cell transcriptomics technology to investigate the changes in various cell subtypes during MIRI and the regulatory network of ferroptosis-related genes and immune infiltration.

Methods

Datasets GSE146285, GSE83472, GSE61592, and GSE160516 were obtained from Gene Expression Omnibus. Each cell subtype in the tissue samples was documented. The Seurat package was used for data preprocessing, standardization, and clustering. Cellphonedb was used to investigate the ligand-receptor interactions between cells. The hdWGCNA analysis was used to create a gene co-expression network. GSVA and GSEA were combined to perform functional enrichment and pathway analysis on the gene set. Furthermore, characteristic genes of the disease were identified using Lasso regression and SVM algorithms. Immune cell infiltration analysis was also performed. MIRI rat models were created, and samples were taken for RT-qPCR and Western blot validation.

Results

The proportion of MIRI samples in the C2, C6, and C11 subtypes was significantly higher than that of control samples. Three genes associated with ferroptosis (CD44, Cfl1, and Zfp36) were identified as MIRI core genes. The expression of these core genes was significantly correlated with mast cells and monocyte immune infiltrating cells. The experimental validation confirmed the upregulation of Cd44 and Zfp36 expression levels in MIRI, consistent with current study trends.

Conclusion

This study used single-cell transcriptomics technology to investigate the molecular mechanisms underpinning MIRI. Numerous important cell subtypes, gene regulatory networks, and disease-associated immune infiltration were also discovered. These findings provide new information and potential therapeutic targets for MIRI diagnosis and treatment.

Skin Telocytes Could Fundament the Cellular Mechanisms of Wound Healing in Platelet-Rich Plasma Administration

For more than 40 years, autologous platelet concentrates have been used in clinical medicine. Since the first formula used, namely platelet-rich plasma (PRP), other platelet concentrates have been experimented with, including platelet-rich fibrin and concentrated growth factor. Platelet concentrates have three standard characteristics: they act as scaffolds, they serve as a source of growth factors and cytokines, and they contain live cells. PRP has become extensively used in regenerative medicine for the successful treatment of a variety of clinical (non-)dermatological conditions like alopecies, acne scars, skin burns, skin ulcers, muscle, cartilage, and bone repair, and as an adjuvant in post-surgery wound healing, with obvious benefits in terms of functionality and aesthetic recovery of affected tissues/organs. These indications were well documented, and a large amount of evidence has already been published supporting the efficacy of this method. The primordial principle behind minimally invasive PRP treatments is the usage of the patient's own platelets. The benefits of the autologous transplantation of thrombocytes are significant, representing a fast and economic method that requires only basic equipment and training, and it is biocompatible, thus being a low risk for the patient (infection and immunological reactions can be virtually disregarded). Usually, the structural benefits of applying PRP are attributed to fibroblasts only, as they are considered the most numerous cell population within the interstitium. However, this apparent simplistic explanation is still eluding those different types of interstitial cells (distinct from fibroblasts) that are residing within stromal tissue, e.g., telocytes (TCs). Moreover, dermal TCs have an already documented potential in angiogenesis (extra-cutaneous, but also within skin), and their implication in skin recovery in a few dermatological conditions was attested and described ultrastructurally and immunophenotypically. Interestingly, PRP biochemically consists of a series of growth factors, cytokines, and other molecules, to which TCs have also proven to have a positive expression. Thus, it is attractive to hypothesize and to document any tissular collaboration between cutaneous administered PRP and local dermal TCs in skin recovery/repair/regeneration. Therefore, TCs could be perceived as the missing link necessary to provide a solid explanation of the good results achieved by administering PRP in skin-repairing processes.

Fibroblast and myofibroblast activation in normal tissue repair and fibrosis

The term 'fibroblast' often serves as a catch-all for a diverse array of mesenchymal cells, including perivascular cells, stromal progenitor cells and bona fide fibroblasts. Although phenotypically similar, these subpopulations are functionally distinct, maintaining tissue integrity and serving as local progenitor reservoirs. In response to tissue injury, these cells undergo a dynamic fibroblast-myofibroblast transition, marked by extracellular matrix secretion and contraction of actomyosin-based stress fibres. Importantly, whereas transient activation into myofibroblasts aids in tissue repair, persistent activation triggers pathological fibrosis. In this Review, we discuss the roles of mechanical cues, such as tissue stiffness and strain, alongside cell signalling pathways and extracellular matrix ligands in modulating myofibroblast activation and survival. We also highlight the role of epigenetic modifications and myofibroblast memory in physiological and pathological processes. Finally, we discuss potential strategies for therapeutically interfering with these factors and the associated signal transduction pathways to improve the outcome of dysregulated healing.

The mechano-chemical circuit in fibroblasts and dendritic cells drives basal cell proliferation in psoriasis

Psoriasis is an intractable immune-mediated disorder that disrupts the skin barrier. While studies have dissected the mechanism by which immune cells directly regulate epidermal cell proliferation, the involvement of dermal fibroblasts in the progression of psoriasis remains unclear. Here, we identified that signals from dendritic cells (DCs) that migrate to the dermal-epidermal junction region enhance dermal stiffness by increasing extracellular matrix (ECM) expression, which further promotes basal epidermal cell hyperproliferation. We analyzed cell-cell interactions and observed stronger interactions between DCs and fibroblasts than between DCs and epidermal cells. Using single-cell RNA (scRNA) sequencing, spatial transcriptomics, immunostaining, and stiffness measurement, we found that DC-secreted LGALS9 can be received by CD44+ dermal fibroblasts, leading to increased ECM expression that creates a stiffer dermal environment. By employing mouse psoriasis and skin organoid models, we discovered a mechano-chemical signaling pathway that originates from DCs, extends to dermal fibroblasts, and ultimately enhances basal cell proliferation in psoriatic skin.

Chip collection of hepatocellular carcinoma based on O2 heterogeneity from patient tissue

Hepatocellular carcinoma frequently recurs after surgery, necessitating personalized clinical approaches based on tumor avatar models. However, location-dependent oxygen concentrations resulting from the dual hepatic vascular supply drive the inherent heterogeneity of the tumor microenvironment, which presents challenges in developing an avatar model. In this study, tissue samples from 12 patients with hepatocellular carcinoma are cultured directly on a chip and separated based on preference of oxygen concentration. Establishing a dual gradient system with drug perfusion perpendicular to the oxygen gradient enables the simultaneous separation of cells and evaluation of drug responsiveness. The results are further cross-validated by implanting the chips into mice at various oxygen levels using a patient-derived xenograft model. Hepatocellular carcinoma cells exposed to hypoxia exhibit invasive and recurrent characteristics that mirror clinical outcomes. This chip provides valuable insights into treatment prognosis by identifying the dominant hepatocellular carcinoma type in each patient, potentially guiding personalized therapeutic interventions.

Dynamics of CD44+ bovine nucleus pulposus cells with inflammation

Intervertebral Disc (IVD) degeneration has been associated with a chronic inflammatory response, but knowledge on the contribution of distinct IVD cells, namely CD44, to the progression of IVD degeneration remains elusive. Here, bovine nucleus pulposus (NP) CD44 cells were sorted and compared by gene expression and proteomics with the negative counterpart. NP cells were then stimulated with IL-1b (10 ng/ml) and dynamics of CD44 gene and protein expression was analyzed upon pro-inflammatory treatment. The results emphasize that CD44 has a multidimensional functional role in IVD metabolism, ECM synthesis and production of neuropermissive factors. CD44 widespread expression in NP was partially associated with CD14 and CD45, resulting in the identification of distinct cell subsets. In conclusion, this study points out CD44 and CD44-based cell subsets as relevant targets in the modulation of the IVD pro-inflammatory/degenerative cascade.

Efficacy of Topical Application of Chum Salmon (Oncorhynchus keta) Skin-derived Collagen Extracts in Improving Oral Traumatic Ulcer Healing

Background

Traumatic ulcer is a wound on the oral mucosa that often causes pain and impaired eating function. Healing of these wounds takes a long time and can interfere with an individual's daily activities. One therapeutic approach that is being developed is the use of topical application of chum salmon skin-derived collagen extract. Collagen is the main component of the extracellular matrix and plays a major role in wound healing. The skin of chum salmon (Oncorhynchus keta) contains collagen that is effective for the treatment of wounds.

Aim

The aim of this study was to evaluate the effectiveness of topical applications of chum salmon (O. keta) skin-derived collagen extracts in improving the healing of traumatic ulcers through analysis of neutrophil and macrophage numbers and collagen density.

Materials and Methods

Twenty-four male Wistar rats were randomly divided into four groups consisting of six rats each. The labial mucosa of the lower lips of the rats was injured with heated amalgam stoppers to create oral traumatic ulcers. Group 1 was a control group; in Groups 2, 3, and 4, 25%, 50%, and 75% of collagen extracts from chum salmon (O. keta) skin were applied topically once a day for 7 days, respectively. The neutrophil and macrophage numbers were observed by hematoxylin and eosin staining. Masson's Trichrome staining was used to analyze the collagen density. Data were analyzed using one-way analysis of variance and continued with post hoc least significant difference tests. Significance is considered if P < 0.05.

Results

The oral traumatic ulcers gradually healed until day 7. The number of neutrophils and macrophages was significantly decreased in the treatment groups, and collagen density was increased, compared to the control group (P < 0.05). The decrease of neutrophil and macrophage numbers occurred significantly with the increased collagen extract concentrations (P < 0.05). Collagen density also increased significantly with the increased collagen extract concentrations (P < 0.05).

Conclusion

Topical applications of chum salmon (O. keta) skin-derived collagen extracts accelerate the healing process of oral traumatic ulcers by decreasing neutrophil and macrophage numbers and increasing collagen density.

Aging-Related Rotator Cuff Tears: Molecular Mechanisms and Implications for Clinical Management

Shoulder pain and disabilities are prevalent issues among the elderly population, with rotator cuff tear (RCT) being one of the leading causes. Although surgical treatment has shown some success, high postoperative retear rates remain a great challenge, particularly in elderly patients. Aging-related degeneration of muscle, tendon, tendon-to-bone enthesis, and bone plays a critical role in the development and prognosis of RCT. Studies have demonstrated that aging worsens muscle atrophy and fatty infiltration, alters tendon structure and biomechanical properties, exacerbates enthesis degeneration, and reduces bone density. Although recent researches have contributed to understanding the pathophysiological mechanisms of aging-related RCT, a comprehensive systematic review of this topic is still lacking. Therefore, this article aims to present a review of the pathophysiological changes and their clinical significance, as well as the molecular mechanisms underlying aging-related RCT, with the goal of shedding light on new therapeutic approaches to reduce the occurrence of aging-related RCT and improve postoperative prognosis in elderly patients.

Comprehensive single-cell analysis reveals heterogeneity of fibroblast subpopulations in ovarian cancer tissue microenvironment

Background

Ovarian cancer, as a highly malignant tumor, features the critical involvement of tumor-associated fibroblasts in the ovarian cancer tissue microenvironment. However, due to the apparent heterogeneity within fibroblast subpopulations, the specific functions of these subpopulations in the ovarian cancer tissue microenvironment remain insufficiently elucidated.

Methods

In this study, we integrated single-cell sequencing data from 32 ovarian cancer samples derived from four distinct cohorts and 3226 bulk RNA-seq data from GEO and TCGA-OV cohorts. Utilizing computational frameworks such as Seurat, Monocle 2, Cellchat, and others, we analyzed the characteristics of the ovarian cancer tissue microenvironment, focusing particularly on fibroblast subpopulations and their differentiation trajectories. Employing the CIBERSORTX computational framework, we assessed various cellular components within the ovarian cancer tissue microenvironment and evaluated their associations with ovarian cancer prognosis. Additionally, we conducted Mendelian randomization analysis based on cis-eQTL to investigate causal relationships between gene expression and ovarian cancer.

Results

Through integrative analysis, we identified 13 major cell types present in ovarian cancer tissues, including CD8+ T cells, malignant cells, and fibroblasts. Analysis of the tumor microenvironment (TME) cell proportions revealed a significant increase in the proportion of CD8+ T cells and CD4+ T cells in tumor tissues compared to normal tissues, while fibroblasts predominated in normal tissues. Further subgroup analysis of fibroblasts identified seven subgroups, with the MMP11+Fib subgroup showing the highest activity in the TGFβ signaling pathway. Single-cell analysis suggested that oxidative phosphorylation could be a key pathway driving fibroblast differentiation, and the ATRNL1+KCN + Fib subgroup exhibited chromosomal copy number variations. Prognostic analysis using a large sample size indicated that high infiltration of MMP11+ fibroblasts was associated with poor prognosis in ovarian cancer. SMR analysis identified 132 fibroblast differentiation-related genes, which were linked to pathways such as platinum drug resistance.

Conclusions

In the context of ovarian cancer, fibroblasts expressing MMP11 emerge as the primary drivers of the TGF-beta signaling pathway. Their presence correlates with an increased risk of adverse ovarian prognoses. Additionally, the genetic regulation governing the differentiation of fibroblasts associated with ovarian cancer correlates with the emergence of drug resistance.

Acute exposure to ultraviolet radiation targets proteins involved in collagen fibrillogenesis

Introduction: Exposure to chronic, low-dose UV irradiation (UVR) can lead to premature ageing of the skin. Understanding which proteins are affected by acute UVR and photo-dynamically produced reactive oxygen species (ROS) could help to inform strategies to delay photoageing. Conventional biochemical analyses can be used to characterize UVR/ROS-induced damage on a protein-by-protein basis and we have previously shown using SDS-PAGE that collagen I and plasma fibronectin are respectively resistant and susceptible to physiological doses of UVR. The aim of this study was to screen a complex proteome for UVR-affected proteins. Methods: This study employed a sensitive mass spectrometry technique (peptide location fingerprinting: PLF) which can identify structure associated differences following trypsin digestion to characterize the impact of UVR exposure on purified collagen I and tissue fibronectin and to identify UVR-susceptible proteins in an ECM-enriched proteome. Results: Using LC/MS-MS and PLF we show that purified mature type-I collagen is resistant to UVR, whereas purified tissue fibronectin is susceptible. UV irradiation of a human dermal fibroblast-deposited ECM-enriched proteome in vitro, followed by LC/MS-MS and PLF analysis revealed two protein cluster groups of UV susceptible proteins involved in i) matrix collagen fibril assembly and ii) protein translation and motor activity. Furthermore, PLF highlighted UV susceptible domains within targeted matrix proteins, suggesting that UV damage of matrix proteins is localized. Discussion: Here we show that PLF can be used to identify protein targets of UVR and that collagen accessory proteins may be key targets in UVR exposed tissues.

Food Safety Assessment and Nutraceutical Outcomes of Dairy By-Products: Ovine Milk Whey as Wound Repair Enhancer on Injured Human Primary Gingival Fibroblasts

The valorization of milk whey appears to be a promising strategy for managing by-products from dairy food industries, which incur demanding economic costs for treatment and/or disposal. Thanks to its numerous bioactive components, whey is expected to be increasingly incorporated into foods in the future. We investigated the safety of ovine milk whey through in vitro experiments on human primary gingival fibroblast (HGF-1) proliferation and wound healing. Fibroblasts play a crucial role in the repair processes from the late inflammatory phase until the final stages. Cells treated with varying concentrations of ovine whey (0.01%, 0.1%, 1%, and 10%) were able to close wounds more rapidly than vehicle-treated cells. Time- and dose-dependent responses were observed in cell populations exposed to ovine whey. Specifically, wounds treated with 0.1% and 10% milk whey showed better migratory capabilities compared to those treated with 0.01% and 1% milk whey after 24 and 48 h. In addition, ovine milk whey stimulates extracellular matrix deposition, as evidenced by the increasing levels of CD44 antigen density evaluated through FACS analysis, as well as COL1A1 expression measured both via RT-qPCR and immunofluorescence. This phenomenon was particularly evident at concentrations of 0.01% and 10%. Ensuring quality and safety has become a major concern for health authorities in the food industry. Our findings suggest that ovine milk whey is safe and possesses regenerative properties. It facilitates tissue re-establishment following exposure to environmental stress, particularly accelerating gingival wound closure.

Technical optimization of spatially resolved single-cell transcriptomic datasets to study clinical liver disease

Single cell and spatially resolved 'omic' techniques have enabled deep characterization of clinical pathologies that remain poorly understood, providing unprecedented insights into molecular mechanisms of disease. However, transcriptomic platforms are costly, limiting sample size, which increases the possibility of pre-analytical variables such as tissue processing and storage procedures impacting RNA quality and downstream analyses. Furthermore, spatial transcriptomics have not yet reached single cell resolution, leading to the development of multiple deconvolution methods to predict individual cell types within each transcriptome 'spot' on tissue sections. In this study, we performed spatial transcriptomics and single nucleus RNA sequencing (snRNAseq) on matched specimens from patients with either histologically normal or advanced fibrosis to establish important aspects of tissue handling, data processing, and downstream analyses of biobanked liver samples. We observed that tissue preservation technique impacts transcriptomic data, especially in fibrotic liver. Single cell mapping of the spatial transcriptome using paired snRNAseq data generated a spatially resolved, single cell dataset with 24 unique liver cell phenotypes. We determined that cell-cell interactions predicted using ligand-receptor analysis of snRNAseq data poorly correlated with cellular relationships identified using spatial transcriptomics. Our study provides a framework for generating spatially resolved, single cell datasets to study gene expression and cell-cell interactions in biobanked clinical samples with advanced liver disease.

Pathway analysis of spermidine anti-oxidative stress and inducing autophagy in granulosa cells of Sichuan white geese

Spermidine, a natural polyamine, has been proven antioxidant function, but its pathway and mechanism of action remain unclear. Based on the oxidative stress model by 3-nitropropionic acid (3-NPA), the study explored the pathways by spermidine to rescue oxidative stress via autophagic process in goose granulosa cells by RNA-seq and RNA interference. In transcriptional regulation, in addition to KEGG pathways related to cell proliferation and differentiation, lots of KEGG pathways associated with inflammation, metabolism, and signaling were also significantly enriched in 3-NPA vs. 3-NPA + spermidine treatments. Six key genes (JUN, CD44, KITLG, RND2, BMP4 and KALRN) involved in spermidine-mediated anti-oxidative stress were screened. Furthermore, the experimental results showed that spermidine (80 μmol/L) significantly increased autophagic gene expression in goose granulosa cells, while EP300-siRNA or MAP1S-siRNA also significantly increased autophagic process. The autophagic gene expressions were no difference between EP300-siRNA and EP300-siRNA + spermidine treatments, although spermidine significantly increased autophagic process of granulosa cells compared to MAP1S-siRNA alone. In addition, inhibition of mTOR pathway significantly increased autophagic gene expression, which was further enhanced by spermidine in combined with mTOR inhibitor. These results suggest that spermidine can alleviate oxidative stress by inducing autophagy regulated by EP300, MAP1S and mTOR as well as regulating other independent gene expressions in goose granulosa cells.

Scars

Wound healing occurs as a response to disruption of the epidermis and dermis. It is an intricate and well-orchestrated response with the goal to restore skin integrity and function. However, in hundreds of millions of patients, skin wound healing results in abnormal scarring, including keloid lesions or hypertrophic scarring. Although the underlying mechanisms of hypertrophic scars and keloid lesions are not well defined, evidence suggests that the changes in the extracellular matrix are perpetuated by ongoing inflammation in susceptible individuals, resulting in a fibrotic phenotype. The lesions then become established, with ongoing deposition of excess disordered collagen. Not only can abnormal scarring be debilitating and painful, it can also cause functional impairment and profound changes in appearance, thereby substantially affecting patients' lives. Despite the vast demand on patient health and the medical society, very little progress has been made in the care of patients with abnormal scarring. To improve the outcome of pathological scarring, standardized and innovative approaches are required.

A Chitosan-Based Biomaterial Combined with Mesenchymal Stem Cell-Conditioned Medium for Wound Healing and Skin Regeneration

The aim of this study was to provide a beneficial treatment effect of novel chitosan bio-polymeric material enriched with mesenchymal stem cell products derived from the canine adipose tissue (AT-MSC) on the artificial skin defect in a rabbit model. For the objectivity of the regeneration evaluation, we used histological analysis and a scoring system created by us, taking into account all the attributes of regeneration, such as inflammatory reaction, necrosis, granulation, formation of individual skin layers and hair follicles. We observed an acceleration and improvement in the healing of an artificially created skin defect after eight and ten weeks in comparison with negative control (spontaneous healing without biomaterial). Moreover, we were able to described hair follicles and epidermis layer in histological skin samples treated with a chitosan-based biomaterial on the eighth week after grafting.

The Hyaluronan/CD44 Axis: A Double-Edged Sword in Cancer

Hyaluronic acid (HA) receptor CD44 is widely used for identifying cancer stem cells and its activation promotes stemness. Recent evidence shows that overexpression of CD44 is associated with poor prognosis in most human cancers and mediates therapy resistance. For these reasons, in recent years, CD44 has become a treatment target in precision oncology, often via HA-conjugated antineoplastic drugs. Importantly, HA molecules of different sizes have a dual effect and, therefore, may enhance or attenuate the CD44-mediated signaling pathways, as they compete with endogenous HA for binding to the receptors. The magnitude of these effects could be crucial for cancer progression, as well as for driving the inflammatory response in the tumor microenvironment. The increasingly common use of HA-conjugated drugs in oncology, as well as HA-based compounds as adjuvants in cancer treatment, adds further complexity to the understanding of the net effect of hyaluronan-CD44 activation in cancers. In this review, I focus on the significance of CD44 in malignancy and discuss the dichotomous function of the hyaluronan/CD44 axis in cancer progression.

Targeting CD44 Receptor Pathways in Degenerative Joint Diseases: Involvement of Proteoglycan-4 (PRG4)

Rheumatoid arthritis (RA), osteoarthritis (OA), and gout are the most prevalent degenerative joint diseases (DJDs). The pathogenesis underlying joint disease in DJDs remains unclear. Considering the severe toxicities reported with anti-inflammatory and disease-modifying agents, there is a clear need to develop new treatments that are specific in their effect while not being associated with significant toxicities. A key feature in the development of joint disease is the overexpression of adhesion molecules, e.g., CD44. Expression of CD44 and its variants in the synovial tissues of patients with DJDs is strongly associated with cartilage damage and appears to be a predicting factor of synovial inflammation in DJDs. Targeting CD44 and its downstream signaling proteins has emerged as a promising therapeutic strategy. PRG4 is a mucinous glycoprotein that binds to the CD44 receptor and is physiologically involved in joint lubrication. PRG4-CD44 is a pivotal regulator of synovial lining cell hemostasis in the joint, where lack of PRG4 expression triggers chronic inflammation and fibrosis, driven by persistent activation of synovial cells. In view of the significance of CD44 in DJD pathogenesis and the potential biological role for PRG4, this review aims to summarize the involvement of PRG4-CD44 signaling in controlling synovitis, synovial hypertrophy, and tissue fibrosis in DJDs.

Technical optimization of spatially resolved single-cell transcriptomic datasets to study clinical liver disease

Single cell and spatially resolved 'omic' techniques have enabled deep characterization of clinical pathologies that remain poorly understood, providing unprecedented insights into molecular mechanisms of disease. However, transcriptomic platforms are costly, limiting sample size, which increases the possibility of pre-analytical variables such as tissue processing and storage procedures impacting RNA quality and downstream analyses. Furthermore, spatial transcriptomics have not yet reached single cell resolution, leading to the development of multiple deconvolution methods to predict individual cell types within each transcriptome 'spot' on tissue sections. In this study, we performed spatial transcriptomics and single nucleus RNA sequencing (snRNASeq) on matched specimens from patients with either histologically normal or advanced fibrosis to establish important aspects of tissue handling, data processing, and downstream analyses of biobanked liver samples. We observed that tissue preservation technique impacts transcriptomic data, especially in fibrotic liver. Deconvolution of the spatial transcriptome using paired snRNASeq data generated a spatially resolved, single cell dataset with 24 unique liver cell phenotypes. We determined that cell-cell interactions predicted using ligand-receptor analysis of snRNASeq data poorly correlated with celullar relationships identified using spatial transcriptomics. Our study provides a framework for generating spatially resolved, single cell datasets to study gene expression and cell-cell interactions in biobanked clinical samples with advanced liver disease.

In vitro activity of hyaluronic acid and human serum on periodontal biofilm and periodontal ligament fibroblasts

OBJECTIVES

A beneficial effect of cross-linked hyaluronic acid (cHA) on periodontal wound healing and regeneration has recently been demonstrated. The present in vitro study was designed to obtain deeper knowledge on the effect of cHA when applied in the gingival sulcus (serum-rich environment) during non-surgical periodontal therapy.

MATERIALS AND METHODS

The influence of cHA, human serum (HS), and cHA/HS on (i) a 12-species biofilm formation, (ii) the adhesion of periodontal ligament fibroblasts (PDLF) to dentine surface, (iii) the expression and secretion of interleukin-8, and (iv) the expression of receptors of HA in PDLF and gingival fibroblasts (GF) were evaluated.

RESULTS

At 4 h of biofilm formation, cHA and HS in combination (cHA/HS) slightly decreased the colony-forming unit counts in biofilm whereas the metabolic activity of biofilm was reduced in all test groups (cHA, HS, cHA/HS) vs. control. At 24 h, the quantity of biofilm was reduced in all test groups vs. untreated control. The test substances did not affect adhesion of PDLF to dentin. HS increased the expression of IL-8 by PDLF and GF which was partially downregulated by cHA. HS and/or cHA promoted the expression of the HA receptor RHAMM in GF but not in PDLF.

CONCLUSIONS

In summary, the present data indicate that serum neither negatively affect the activity of cHA against periodontal biofilm nor had any unwanted influence on the activity of PDLF.

CLINICAL RELEVANCE

These findings lend additional support for the positive effects of cHA on cells involved in periodontal wound healing, thus pointing to its potential use in non-surgical periodontal therapy.

Mesoporous Composite Bioactive Compound Delivery System for Wound-Healing Processes

Currently, the treatment of wounds is still a challenge for healthcare professionals due to high complication incidences and social impacts, and the development of biocompatible and efficient medicines remains a goal. In this regard, mesoporous materials loaded with bioactive compounds from natural extracts have a high potential for wound treatment due to their nontoxicity, high loading capacity and slow drug release. MCM-41-type mesoporous material was synthesized by using sodium trisilicate as a silica source at room temperature and normal pressure. The synthesized mesoporous silica was characterized by using Scanning Electron Microscopy (SEM), Transmission Electron Microscopy (TEM), N2 absorption-desorption (BET), Dynamic Light Scattering (DLS) and Fourier transform infrared spectroscopy (FT-IR), revealing a high surface area (BET, 1244 m2/g); pore diameter of approx. 2 nm; and a homogenous, ordered and hexagonal geometry (TEM images). Qualitative monitoring of the desorption degree of the Salvia officinalis (SO) extract, rich in ursolic acid and oleanolic acid, and Calendula officinalis (CO) extract, rich in polyphenols and flavones, was performed via the continuous recording of the UV-VIS spectra at predetermined intervals. The active ingredients in the new composite MCM-41/sage and marigold (MCM-41/SO&CO) were quantified by using HPLC-DAD and LC-MS-MS techniques. The evaluation of the biological composites' activity on the wound site was performed on two cell lines, HS27 and HaCaT, naturally involved in tissue-regeneration processes. The experimental results revealed the ability to stimulate collagen biosynthesis, the enzymatic activity of the main metalloproteinases (MMP-2 and MMP-9) involved in tissue remodeling processes and the migration rate in the wound site, thus providing insights into the re-epithelializing properties of mesoporous composites.

Adhesion tunes speed and persistence by coordinating protrusions and extracellular matrix remodeling

Cell migration through 3D environments is essential to development, disease, and regeneration processes. Conceptual models of migration have been developed primarily on the basis of 2D cell behaviors, but a general understanding of 3D cell migration is still lacking due to the added complexity of the extracellular matrix. Here, using a multiplexed biophysical imaging approach for single-cell analysis of human cell lines, we show how the subprocesses of adhesion, contractility, actin cytoskeletal dynamics, and matrix remodeling integrate to produce heterogeneous migration behaviors. This single-cell analysis identifies three modes of cell speed and persistence coupling, driven by distinct modes of coordination between matrix remodeling and protrusive activity. The framework that emerges establishes a predictive model linking cell trajectories to distinct subprocess coordination states.

Positive feedback loops between fibroblasts and the mechanical environment contribute to dermal fibrosis

Dermal fibrosis is characterized by excessive deposition of extracellular matrix in the dermis and affects millions of people worldwide and causes limited movement, disfigurement and psychological distress in patients. Fibroblast dysfunction of plays a central role in the pathogenesis of dermal fibrosis and is controlled by distinct factors. Recent studies support the hypothesis that fibroblasts can drive matrix deposition and stiffening, which in turn can exacerbate the functional dysregulation of fibroblasts. Ultimately, through a positive feedback loop, uncontrolled pathological fibrosis develops. This review aims to summarize the phenomenon and mechanism of the positive feedback loop in dermal fibrosis, and discuss potential therapeutic targets to help further elucidate the pathogenesis of dermal fibrosis and develop therapeutic strategies. In this review, fibroblast-derived compositional and structural changes in the ECM that lead to altered mechanical properties are briefly discussed. We focus on the mechanisms by which mechanical cues participate in dermal fibrosis progression. The mechanosensors discussed in the review include integrins, DDRs, proteoglycans, and mechanosensitive ion channels. The FAK, ERK, Akt, and Rho pathways, as well as transcription factors, including MRTF and YAP/TAZ, are also discussed. In addition, we describe stiffness-induced biological changes in the ECM on fibroblasts that contribute to the formation of a positive feedback loop. Finally, we discuss therapeutic strategies to treat the vicious cycle and present important suggestions for researchers conducting in-depth research.

Single-cell sequencing reveals the landscape of the human brain metastatic microenvironment

Brain metastases is the most common intracranial tumor and account for approximately 20% of all systematic cancer cases. It is a leading cause of death in advanced-stage cancer, resulting in a five-year overall survival rate below 10%. Therefore, there is a critical need to identify effective biomarkers that can support frequent surveillance and promote efficient drug guidance in brain metastasis. Recently, the remarkable breakthroughs in single-cell RNA-sequencing (scRNA-seq) technology have advanced our insights into the tumor microenvironment (TME) at single-cell resolution, which offers the potential to unravel the metastasis-related cellular crosstalk and provides the potential for improving therapeutic effects mediated by multifaceted cellular interactions within TME. In this study, we have applied scRNA-seq and profiled 10,896 cells collected from five brain tumor tissue samples originating from breast and lung cancers. Our analysis reveals the presence of various intratumoral components, including tumor cells, fibroblasts, myeloid cells, stromal cells expressing neural stem cell markers, as well as minor populations of oligodendrocytes and T cells. Interestingly, distinct cellular compositions are observed across different samples, indicating the influence of diverse cellular interactions on the infiltration patterns within the TME. Importantly, we identify tumor-associated fibroblasts in both our in-house dataset and external scRNA-seq datasets. These fibroblasts exhibit high expression of type I collagen genes, dominate cell-cell interactions within the TME via the type I collagen signaling axis, and facilitate the remodeling of the TME to a collagen-I-rich extracellular matrix similar to the original TME at primary sites. Additionally, we observe M1 activation in native microglial cells and infiltrated macrophages, which may contribute to a proinflammatory TME and the upregulation of collagen type I expression in fibroblasts. Furthermore, tumor cell-specific receptors exhibit a significant association with patient survival in both brain metastasis and native glioblastoma cases. Taken together, our comprehensive analyses identify type I collagen-secreting tumor-associated fibroblasts as key mediators in metastatic brain tumors and uncover tumor receptors that are potentially associated with patient survival. These discoveries provide potential biomarkers for effective therapeutic targets and intervention strategies.

Photothermal Controlled-Release Immunomodulatory Nanoplatform for Restoring Nerve Structure and Mechanical Nociception in Infectious Diabetic Ulcers

Infectious diabetic ulcers (IDU) require anti-infection, angiogenesis, and nerve regeneration therapy; however, the latter has received comparatively less research attention than the former two. In particular, there have been few reports on the recovery of mechanical nociception. In this study, a photothermal controlled-release immunomodulatory hydrogel nanoplatform is tailored for the treatment of IDU. Due to a thermal-sensitive interaction between polydopamine-reduced graphene oxide (pGO) and the antibiotic mupirocin, excellent antibacterial efficacy is achieved through customized release kinetics. In addition, Trem2+ macrophages recruited by pGO regulate collagen remodeling and restore skin adnexal structures to alter the fate of scar formation, promote angiogenesis, accompanied by the regeneration of neural networks, which ensures the recovery of mechanical nociception and may prevent the recurrence of IDU at the source. In all, a full-stage strategy from antibacterial, immune regulation, angiogenesis, and neurogenesis to the recovery of mechanical nociception, an indispensable neural function of skin, is introduced to IDU treatment, which opens up an effective and comprehensive therapy for refractory IDU.

Prediction of CD44 Structure by Deep Learning-Based Protein Modeling

CD44 is a cell surface glycoprotein transmembrane receptor that is involved in cell-cell and cell-matrix interactions. It crucially associates with several molecules composing the extracellular matrix, the main one of which is hyaluronic acid. It is ubiquitously expressed in various types of cells and is involved in the regulation of important signaling pathways, thus playing a key role in several physiological and pathological processes. Structural information about CD44 is, therefore, fundamental for understanding the mechanism of action of this receptor and developing effective treatments against its aberrant expression and dysregulation frequently associated with pathological conditions. To date, only the structure of the hyaluronan-binding domain (HABD) of CD44 has been experimentally determined. To elucidate the nature of CD44s, the most frequently expressed isoform, we employed the recently developed deep-learning-based tools D-I-TASSER, AlphaFold2, and RoseTTAFold for an initial structural prediction of the full-length receptor, accompanied by molecular dynamics simulations on the most promising model. All three approaches correctly predicted the HABD, with AlphaFold2 outperforming D-I-TASSER and RoseTTAFold in the structural comparison with the crystallographic HABD structure and confidence in predicting the transmembrane helix. Low confidence regions were also predicted, which largely corresponded to the disordered regions of CD44s. These regions allow the receptor to perform its unconventional activity.

CD44 Expression in Renal Tissue Is Associated with an Increase in Urinary Levels of Complement Components in Chronic Glomerulopathies

It is suggested that activated CD44+ cells play a profibrogenic role in the pathogenesis of active glomerulopathies. Complement activation is also involved in renal fibrogenesis. The aim of the study was to evaluate the role of the activation of CD44+ cells in the kidney tissue and complement components' filtration to the urine as factors of renal tissue fibrosis in patients with glomerulopathies. In total, 60 patients with active glomerulopathies were included in our study: 29 patients with focal segmental glomerulosclerosis (FSGS), 10 patients with minimal change disease (MCD), 10 patients with membranous nephropathy (MN), and 11 patients with IgA nephropathy. The immunohistochemical peroxidase method was used to study the expression of CD44+ in kidney biopsies. Components of complement were analyzed in urine by the multiple reaction monitoring (MRM) approach using liquid chromatography. Strong CD44 expression was noted predominantly in PEC and mesangial cells (MC) in patients with FSGS, and to a lesser extent, in patients with MN and IgA nephropathy, and it was absent in patients with MCD. Expression of profibrogenic CD44+ in glomeruli correlated with the levels of proteinuria and complement C2, C3, and C9 components, and CFB and CFI in urine. The CD44+ expression scores in the renal interstitium correlated with the level of C3 and C9 components of complement in the urine and the area of tubulo-interstitial fibrosis. The strongest expression of CD44+ was found in the glomeruli (MC, PEC, and podocytes) of patients with FSGS compared with other glomerulopathies. The CD44 expression score in the glomeruli and interstitium is associated with high levels of complement components in the urine and renal fibrosis.

Efficacy of stromal vascular fraction and enzyme-free mechanical isolation therapy in experimental full thickness burn wounds

BACKGROUND

Autologous cell suspensions obtained by a stromal vascular fraction (SVF) and enzyme-free mechanical isolation (EMI) are an alternative in the treatment of burn wounds. In this study, we aimed to investigate the effect of autologous cell suspensions obtained by SVF and EMI on full-thickness skin burn wounds.

METHODS

A total of 45 male Sprague-Dawley rats were divided into three groups, SVF group, EMI group, and SVF + EMI group. The groups were also classified as the first, second, and third week of the burn to reveal the effect of the treatment on the burn in the early, middle, and late stages. For treatment, 0.2 ml SVF or 0.2 ml EMI was injected subcutaneously into the burn lesions of the subjects. Histopathological examination was performed on the burn wounds taken at the end of the experiment, and Ki67, CD44, CD73, CD90, and CK17 expressions were evaluated.

RESULTS

Histological examination revealed that there was no improvement in the control samples, but the skin was multicellular, vascularization was present. Histologic scores in all groups was significantly better than control, and SVF + EMI was the best group in terms of recovery (p < 0.05). Ki67, CK17, CD44, CD73, and CD90 expressions were significantly higher in the treatment groups compared to the control (p < 0.05).

CONCLUSION

We found in our study that both applications significantly increased the healing of the burn wound. Moreover, SVF + EMI application provided more improvement than SVF or EMI alone.