Abstract Viable microalgal cells have recently emerged as promising photosynthetic components of advanced wound healing systems because they can combine light-regulated oxygen generation, bioactive metabolite production, intrinsic imaging potential, and engineering flexibility within a single platform. In wounds with impaired or threatened healing such as burn wounds, traumatic full-thickness wounds, infected wounds, and chronic diabetic wounds, hypoxia, excessive inflammation, microbial burden, and impaired angiogenesis collectively hinder tissue repair and limit the efficacy of the currently employed therapies. In this review, the mechanistic basis and translational potential of microalgae in wound care is examined, with a focus on photosynthesis-driven oxygenation, antimicrobial and anti-inflammatory activities, antioxidant effects, immunomodulation, and bioimaging capability. We further summarize how viable microalgal cells or cell-derived products have been incorporated into hydrogels, three-dimensional bioprinted scaffolds, microneedles, electrospun matrices, coatings, and other biohybrid systems to achieve localized oxygen delivery, therapeutic molecule release, and multifunctional wound intervention. Importantly, we discuss the wound type-specific suitability of different microalgae-based platforms and critically compare them with existing oxygenation and antimicrobial strategies. We also highlight key barriers to clinical translation, including immune-mediated clearance, uncertain long-term survival and photosynthetic persistence in hostile wound microenvironments, limited light penetration, biosafety concerns, and challenges in manufacturing and standardization. Overall, microalgae-based wound therapeutics represent a highly promising but still early-stage strategy, and future progress will depend on mechanism-driven design, rigorous in vivo validation, and clinically relevant translational frameworks.
Abstract Background Intestinal barrier failure following ischemia–reperfusion (IR) injury is a critical event that drives lethal systemic complications; however, the specific intercellular signals governing epithelial cell fate under these pathological conditions remain incompletely understood. Methods We performed single-cell RNA sequencing (scRNA-seq) on intestinal tissues from a murine IR model to map intercellular communication networks. The identified ligand–receptor pair was functionally validated using neutrophil-specific thrombospondin-1 (Thbs1) knockout mice, combined with pharmacological inhibition and activation of CD36, as well as biochemical and histological analyses. Results scRNA-seq analysis of the IR-injured gut revealed a key neutrophil–epithelial signaling pathway mediated by the Thbs1–CD36 ligand–receptor pair. Neutrophil-specific genetic ablation of Thbs1 markedly attenuated IR-induced epithelial apoptosis and barrier disruption. Mechanistically, Thbs1 binding to epithelial CD36 activated JNK signaling, mediating a proapoptotic cascade. CD36 inhibition was protective, whereas its activation bypassed the requirement for Thbs1 and provoked mucosal injury. Conclusions Our study elucidates a key mechanism of gut barrier failure and identifies the Thbs1–CD36–JNK axis as a promising therapeutic target for mitigating intestinal IR injury in critical conditions such as burns and shock.
The stagnation of diabetic wound healing is a formidable global health challenge that is fundamentally driven by the dysregulation of macrophage plasticity. In the diabetic microenvironment, macrophages remain in a persistent pro-inflammatory (M1) state and fail to transition to the reparative (M2) phenotype essential for tissue regeneration. This review systematically elucidates the molecular pathology of this 'conversion failure' from a superficial to an in-depth level and provides a detailed explanation of the mechanisms underlying aberrant macrophage polarization in diabetic wounds, ranging from microenvironmental abnormalities to dysregulated signalling pathways. These perturbations create a vicious cycle of chronic inflammation, impaired angiogenesis, and pathological fibrosis. To address these challenges, we comprehensively outline current therapeutic strategies, including approaches that range from the precision molecular reprogramming of intracellular signalling hubs and gene networks to the engineering of microenvironment-responsive biomaterials capable of neutralizing oxidative stress and responding to pathological cues. Furthermore, we highlight the integration of exogenous bioactivity through stem cell- and exosome-based therapies aimed at replenishing the regenerative niche. Additionally, we critically assess translational bottlenecks, suggesting a paradigm shift from the binary M1/M2 model towards targeting intermediate phenotypes identified by single-cell multiomics. By integrating mechanistic insights with advanced immunomodulatory engineering, this review provides a theoretical framework for developing next-generation precision therapies to reverse the chronic nature of diabetic wounds.
Background:Fibrotic scar formation constitutes a significant pathological obstacle that impedes neural regeneration and long-term functional recovery following spinal cord injury (SCI). However, the spatial distribution of key pro-fibrotic mediators within lesion scars and the upstream regulatory mechanisms driving fibroblast activation remain inadequately defined. This study aims to characterize CD36-associated fibrotic remodeling after SCI and to determine whether targeting the c-Jun-Irf8-CD36 axis could attenuate scar formation, improve the regenerative microenvironment, and promote functional recovery. Methods:This study integrated single-cell ribonucleic acid sequencing and spatial transcriptomic profiling to characterize CD36 expression patterns and identify fibroblast subpopulations within SCI scars. Pharmacological interventions were administered in mouse SCI models, using salvianolic acid B (SAB) to inhibit CD36 and T5224 to block AP-1/c-Jun activity. Histological and immunofluorescence analyses were performed to assess fibroblast accumulation, extracellular matrix deposition, angiogenesis, and axonal regeneration, alongside longitudinal behavioral evaluations of locomotor function. Mechanistic validation of the regulatory pathway was achieved through CUT&Tag and dual-luciferase reporter assays to investigate c-Jun-Irf8-CD36 transcriptional regulation, complemented by integrated single-cell/spatial analyses to assess fibroblast subcluster remodeling post-treatment. Results:Spatial and single-cell analyses demonstrated that CD36 is predominantly localized within lesion scars, correlating with fibrotic progression and preferentially upregulated in specific fibroblast subclusters. SAB-mediated CD36 inhibition markedly reduced P4HB+ fibroblast accumulation, alleviated fibrotic deposition, enhanced angiogenesis and axonal regeneration, and improved hindlimb functional recovery. Mechanistically, c-Jun was upregulated in scar regions and indirectly promoted CD36 transcription through Irf8 activation, establishing a c-Jun-Irf8-CD36 signaling axis. CUT&Tag and reporter assays confirmed c-Jun binding to the Irf8 promoter, leading to Irf8-driven CD36 transcription. Similarly, T5224 downregulated CD36 expression, reduced fibroblast aggregation and matrix deposition, facilitated vascular remodeling, and promoted early functional recovery. These findings demonstrate that modulating this signaling pathway can significantly inhibit pathological scar formation and facilitate approximately scar-free healing, thereby providing an ideal microenvironment for tissue regeneration. Multi-omic analyses further revealed that T5224 selectively inhibited the aberrant expansion of CD36+ fibroblast subclusters and reprogrammed their transcriptional states toward a less fibrotic phenotype. Conclusions:The c-Jun-Irf8-CD36 axis serves as a pivotal regulator of fibrotic scar formation after SCI. Targeting this pathway through CD36 inhibition (SAB) or AP-1/c-Jun blockade (T5224) attenuates fibrosis, remodels the scar microenvironment, enhances tissue repair, and promotes functional recovery, highlighting a promising therapeutic strategy for central nervous system injury.
Abstract Background Axonal regeneration following spinal cord injury (SCI) is hindered by the intrinsic inhibitory properties of spinal neurons. While the role of the transcription factor SPI1 (PU.1) has been well established in myeloid cells, its function in neurons, particularly in regulating axonogenesis, remains poorly defined. The data from recent single-cell sequencing studies have indicated that SPI1 is clearly expressed in spinal neurons. Thus, we aimed to explore the effect of SPI1 on axonal growth and its underlying molecular mechanisms. Methods Primary cultured rat spinal neurons, CRISPR/Cas9-mediated spi1 mutation in zebrafish, and neuron-specific AAV9-shRNA delivery after rat spinal cord hemisection were utilized to manipulate SPI1 expression. RNA-seq, luciferase reporter assays, ChIP–qPCR, and Cut & Tag assays were employed to identify and validate Rassf10 as a candidate target gene of SPI1. Axonal outgrowth and functional recovery postinjury were assessed both in vitro and in vivo. Results Neuronal SPI1 expression declined progressively during spinal cord development but was markedly upregulated after SCI. SPI1 knockdown promoted axonal outgrowth, whereas SPI1 overexpression significantly reduced the axonal length. The transcriptomic analysis revealed that Rassf10 is a target gene of SPI1, which was subsequently validated by the results of luciferase reporter, ChIP–qPCR, and Cut & Tag assays. In vivo, spi1 mutation in zebrafish and neuron-specific SPI1 knockdown in rats facilitated axonal regeneration and functional recovery after SCI, as evidenced by significant increases in GAP43, NF200, and 5-HT expression and improved motor function compared with the control animals. The depletion of SPI1 or Rassf10 increased p-p38 MAPK levels and promoted axonal growth, whereas p38 inhibition abrogated these effects. Conclusions SPI1 impairs axonal growth and regrowth by transcriptionally activating Rassf10 expression, with this inhibitory effect mediated by the suppression of p38 MAPK signaling. These findings suggest that targeting the SPI1–Rassf10 pathway represents a promising therapeutic strategy for improving neural repair after SCI.
Abstract Background Keloids, which are characterized by excessive collagen deposition and fibroblast hyperactivation, present significant therapeutic challenges because of their high recurrence rates and incompletely understood pathogenesis. The transforming growth factor-β (TGF-β) pathway is a central driver, but its upstream regulators in the development of skin fibrosis remain elusive. Methods We integrated results of transcriptomic and proteomic analyses of patient-derived keloid and normal skin tissues. Functional validation was performed by using primary keloid fibroblasts (KFs) with gain- and loss-of-function approaches, RNA immunoprecipitation sequencing (RIP-seq), and actinomycin D chase assays. Two independent bleomycin-induced skin fibrosis mouse models were employed for in vivo validation. Results Multiomics profiling revealed that caveolae-associated protein 1 (CAVIN1) was consistently downregulated in keloids. CAVIN1 overexpression in KFs suppressed fibrotic phenotypes, including migration, invasion, collagen contraction, and ECM protein expression. Mechanistically, CAVIN1 directly bound to and stabilized the mitochondrial long noncoding RNA GAS5. This CAVIN1/GAS5 axis inhibited Drp1/Fis1-mediated mitochondrial fission and subsequent reactive oxygen species (ROS) production, leading to the attenuation of the canonical TGF-β/Smad2/3 signalling pathway. Critically, GAS5 silencing abrogated the antifibrotic effects of CAVIN1. Furthermore, database screening revealed that the histone deacetylase inhibitor vorinostat was a CAVIN1-upregulating compound. Both AAV-mediated CAVIN1 overexpression and vorinostat treatment significantly ameliorated skin fibrosis in the mouse models. Conclusions Our study reports a novel CAVIN1/GAS5 axis that concurrently targets mitochondrial fission and the TGF-β/Smad pathway to suppress skin fibrosis. These findings not only reveal a previously unrecognized mechanistic link in keloid pathogenesis but also identify CAVIN1 as a promising therapeutic target, with vorinostat as a potential repurposable drug for treating fibrotic skin disorders.
The mitochondrial unfolded protein response (UPRmt) is a conserved mitochondrial stress response that is activated by mitochondrial dysfunction to maintain proteostasis. Although UPRmt has been extensively studied in aging and cancer, its role in trauma and critical illness remains poorly understood. Here, we propose a unifying conceptual framework in which UPRmt functions as a central stress-integration hub that senses and coordinates adaptive responses following acute injury. We systematically review the mechanisms of UPRmt activation triggered by diverse insults and highlight how UPRmt integrates mitochondrial-nuclear communication, and crosstalk with other stress-responses such as the integrated stress response and mitophagy. Beyond cell-autonomous regulation, UPRmt also coordinates systemic adaptation through mitokine-mediated interorgan signaling. Importantly, we emphasize the context-dependent role of UPRmt in trauma and critical illness. Moderate activation promotes mitochondrial recovery, limits reactive oxygen species accumulation, and supports immune cell function, thereby enhancing tissue resilience and repair. In contrast, sustained or dysregulated UPRmt contributes to mitochondrial failure, sterile inflammation, and the progression to systemic inflammatory response syndrome (SIRS) and multiple organ dysfunction syndrome (MODS). Furthermore, we discuss emerging evidence linking UPRmt to immune regulation and inflammatory responses, and propose that targeting key regulatory nodes within this stress-integration network may offer novel therapeutic strategies for a broad spectrum of human diseases. Crucially, we synthesize how UPRmt mechanisms contribute to post-traumatic mitochondrial damage, sterile inflammation, SIRS, and MODS. We propose that targeting key regulatory nodes within this stress-integration network may offer novel therapeutic strategies for trauma, burns, and critical illness.
Abstract The considerable strain that chronic wounds, including diabetic foot ulcers and pressure sores, place on healthcare systems worldwide is largely attributable to the intricate pathological microenvironment characteristic of these conditions, and conventional therapeutic approaches frequently fall short of desired outcomes, primarily because they cannot effectively disrupt biofilm barriers or adequately adapt to the dynamically changing pathological states involved. Hydrogel microneedles (HMNs) have by contrast emerged as a minimally invasive platform whose distinctive structural features and material properties enable both precise transdermal drug administration and active modulation of the wound microenvironment, and this dual capability is why HMNs are currently transforming chronic wound care by shifting the paradigm from passive occlusive dressings toward more proactive and targeted regenerative interventions. This review summarizes recent progress in HMN-based strategies for chronic wound healing and offers perspectives on future developments, beginning with an examination of fundamental design principles such as material choices, structural arrangements, and the various approaches developed to optimize performance metrics, then tracing the evolution of HMNs from simple drug carriers to intelligent multifunctional systems with special attention to their roles in breaking the pathological cycle through antibacterial effects, reactive oxygen species (ROS) scavenging, immune response modulation, and promotion of angiogenesis. Advances in stimuli-responsive systems that utilize endogenous signals including pH, enzymes, ROS, and glucose or external inputs like light and magnetic fields for on-demand release are also covered, as are combination platforms that integrate different therapeutic strategies for additive benefits. Clinical translation faces a number of challenges despite the considerable promise HMNs exhibit in theranostic applications, regenerative medicine integration, and customized fabrication, with obstacles remaining regarding scalable production that ensures consistent quality across batches, long-term biosafety verification, and unclear regulatory pathways; overcoming these hurdles will depend on sustained interdisciplinary efforts that address both scientific understanding and engineering practicality, and without such collaborative work the meaningful incorporation of HMNs into routine clinical management of chronic wounds along with the consequent availability of more effective, accurate, and intelligent treatment options could be difficult to achieve.
Chronic non-healing wounds, particularly diabetic foot ulcers, persist as a significant clinical challenge due to the limited availability of therapeutic options and the complexity of their pathological microenvironments. Plant-derived extracellular vesicles (PDEVs), which are nanoscale lipid carriers rich in bioactive molecules, have emerged as a promising therapeutic approach due to their low immunogenicity, antioxidant, anti-inflammatory properties, and their ability to promote angiogenesis. Structurally, the biomaterial protects the integrity of PDEVs and extends their residency through modulated release. Biologically, PDEVs enhance the regenerative potential of the material by profoundly reprogramming the local cellular and immune microenvironments. However, their clinical application is severely impeded by their inherent instability in the dynamic wound microenvironment, which includes susceptibility to enzymatic degradation, disruption due to pH fluctuations, and rapid clearance by wound exudate. These factors collectively lead to premature cargo loss and reduced therapeutic efficacy. This review synthesizes how engineered biomaterials, serving as tailored structural platforms for controlled delivery, can overcome these stability challenges specific to PDEVs. By examining loading strategies and design principles, we demonstrate how composite systems surpass single-component therapies in wound models. Lastly, we address translational challenges and propose a development framework that integrates artificial intelligence-driven design with mechanism-guided material optimization. This work lays the groundwork for the rational development of next-generation vesicle-enabled wound therapeutics.
Abstract Wound healing is essential for maintaining organismal homeostasis and barrier function, posing significant challenges particularly in the management of hard-to-heal wounds such as diabetic ulcers. This review systematically summarizes the functional properties of piezoelectric electrospun biomaterials and their biological mechanisms in promoting wound healing via electrical stimulation. Piezoelectric nanofiber wound dressings fabricated by electrospinning technology offer dual advantages: on one hand, their unique fibrous architecture enables adaptation to irregular wound contours, facilitates rapid hemostasis, and provides an effective barrier against microbial invasion; on the other hand, their inherent piezoelectric effect converts micromechanical deformations into localized electrical signals in real time, thereby modulating cellular behaviors and accelerating tissue repair. This review highlights recent studies elucidating the mechanisms by which electrical stimulation (ES) promotes wound healing, and the functional characteristics of piezoelectric fibrous dressings. It aims to establish a theoretical foundation for the rational design and performance optimization of next-generation intelligent piezoelectric wound dressings, thereby advancing their clinical translation and industrial development.
Diabetic foot ulcers (DFUs) represent a growing clinical challenge, driven by an aging global population and the increasing prevalence of diabetes. Affecting millions worldwide, DFUs remain one of the most serious complications of diabetes, frequently progressing to infection, amputation, and elevated mortality. Standard treatments typically include pressure offloading, circulation improvement, infection control, and topical wound care; however, many chronic DFUs fail to respond to these interventions due to persistent inflammation, impaired vascularization, and microbial burden. These challenges have accelerated interest in regenerative medicine approaches, including stem cells, growth factors, and skin substitutes. Among these, skin substitutes have shown particular promise; among Food and Drug Administration-approved options, products such as the collagen-Manuka honey-hydroxyapatite patch from SweetBio (Apis®) have demonstrated improved outcomes in patients with chronic ulcers. Silk fibroin (SF), a natural biopolymer with established clinical use, has emerged as a promising platform for chronic wound management due to its biocompatibility, tunable degradation, and capacity for controlled bio-additive delivery. SF scaffolds can be fabricated through various methods tailored to wound-healing applications: electrospun fibrous mats with high surface-area-to-volume ratio, freeze-dried porous constructs with interconnected architecture, and hydrogels designed for controlled drug delivery. In this review, we critically examine how SF scaffolds enhanced with bio-additives modulate cellular responses, redirect dysregulated healing pathways, accelerate wound closure, and promote tissue regeneration in diabetic wounds. We synthesize recent advances in preclinical and clinical studies, identify key translational barriers, and outline future directions for advancing SF-based dressings toward clinical adoption. Collectively, this review positions bio-enhanced SF scaffolds as next-generation, disease-informed candidates for improving outcomes in chronic DFU care.
Diabetic wound healing is a common yet challenging problem in clinical practice that involves complex pathophysiological processes and frequently progresses to chronic nonhealing wounds, imposing substantial burdens on both healthcare systems and patients while markedly decreasing quality of life. Persistent inflammatory responses represent a fundamental pathological feature of this condition. Accumulating evidence highlights the key role of neutrophil extracellular traps (NETs) in the chronic inflammatory response characteristic of diabetic wounds. As components of the innate immune system, NETs play pivotal roles in both host defence and tissue repair. Neutrophil extracellular trap formation (NETosis) is currently classified as vital NETosis or lytic NETosis. In this review, we synthesize existing evidence on the mechanistic heterogeneity of NETosis and further refine lytic NETosis subtypes on the basis of distinct molecular mechanisms and temporal dynamics-namely, NADPH oxidase 2 (NOX2)-dependent classical lytic NETosis and mitochondrial reactive oxygen species-driven rapid lytic NETosis. We also highlight the functional outcomes of NETs in response to specific stimuli within the diabetic wound milieu. Therapeutic strategies targeting NET formation, degradation, or neutralization have shown considerable promise in preclinical studies; however, their clinical translation will require standardized biomarkers for NET quantification, localized delivery approaches to minimize systemic immunosuppression, and biomarker-guided frameworks to balance the risk of infection against healing benefits.
Abstract Background Burn injuries affect the central nervous system, and evidence suggests they induce changes in cortical excitability related to motor dysfunction. The current study investigated markers of neuroplasticity in the motor cortex and motor performance in the subacute period following burn injury. Methods Thirty-four patients with a non-severe burn injury (total body surface area: 1.0 ± 2.0%; 16 females; age: 46.0 ± 14.0 years) participated in a longitudinal study with assessments ranging from ~1 to ~17 weeks post-injury. Transcranial magnetic stimulation (TMS) was used to evaluate motor cortex excitability and short- and long-intracortical inhibition (SICI; LICI) before and after application of paired associative stimulation (PAS) to induce neuroplasticity. Motor performance was assessed using the Purdue Pegboard. Results Patients showed improvements in bilateral motor performance from ~3 to ~6 weeks post-injury. PAS did not induce any change in net motor cortex excitability or SICI but increased LICI, which was greatest ~6 weeks post-injury. Adjusted modelling showed that greater PAS-induced increase in LICI was associated with better bilateral motor performance, suggesting an association between PAS-induced neuroplasticity of long-acting inhibitory circuits in the primary motor cortex and motor function following burn injury. Discussion These findings highlight a potential role for neuroplasticity of inhibitory circuits in the motor cortex in recovery of motor function following burn injury. Conclusion The data provide a neurophysiological basis to test whether targeting inhibitory networks in the subacute period after burn injury can enhance or expedite functional recovery.
Abstract The mitochondrial unfolded protein response (UPRmt) is a conserved mitochondrial stress response that is activated by mitochondrial dysfunction to maintain proteostasis. Although UPRmt has been extensively studied in aging and cancer, its role in trauma and critical illness remains poorly understood. Here, we propose a unifying conceptual framework in which UPRmt functions as a central stress-integration hub that senses and coordinates adaptive responses following acute injury. We systematically review the mechanisms of UPRmt activation triggered by diverse insults and highlight how UPRmt integrates mitochondrial-nuclear communication, and crosstalk with other stress-responses such as the integrated stress response (ISR) and mitophagy. Beyond cell-autonomous regulation, UPRmt also coordinates systemic adaptation through mitokine-mediated interorgan signaling. Importantly, we emphasize the context-dependent role of UPRmt in trauma and critical illness. Moderate activation promotes mitochondrial recovery, limits reactive oxygen species (ROS) accumulation, and supports immune cell function, thereby enhancing tissue resilience and repair. In contrast, sustained or dysregulated UPRmt contributes to mitochondrial failure, sterile inflammation, and the progression to systemic inflammatory response syndrome (SIRS) and multiple organ dysfunction syndrome (MODS). Furthermore, we discuss emerging evidence linking UPRmt to immune regulation and inflammatory responses, and propose that targeting key regulatory nodes within this stress-integration network may offer novel therapeutic strategies for a broad spectrum of human diseases. Crucially, we synthesize how UPRmt mechanisms contribute to post-traumatic mitochondrial damage, sterile inflammation, SIRS, and MODS. We propose that targeting key regulatory nodes within this stress-integration network may offer novel therapeutic strategies for trauma, burns, and critical illness.
Background:Sepsis-related myocardial dysfunction significantly increases the mortality risk of sepsis. However, its underlying mechanism remains incompletely understood, and effective therapeutic strategies are still lacking. Transcriptomic profiling from septic patients showed endoplasmic reticulum stress (ERS) were the main pathways participating in the occurrence of sepsis myocardial dysfunction. Therefore, this study aimed to explore the protective effect of 4-phenylbutyric acid (4-PBA) on sepsis-induced myocardial injury and specify its molecular regulatory mechanism, to provide experimental basis for clinical intervention of septic myocardial dysfunction. Methods:In vivo and in vitro models of sepsis were used, and 4-PBA (5 mg/kg) was administered for intervention. Mitochondria-associated ER-membrane (MAM) formation, mitochondrial dynamics, mitochondrial function, glycolytic metabolism, and protein lactylation were systematically examined. Molecular docking and site-directed mutation were applied to verify the direct binding and catalytic sites of 4-PBA. Results:4-PBA significantly alleviated sepsis-induced myocardial dysfunction (SIMD). The mechanism was closely related to 4-PBA inhibiting MAM formation and improving the mitochondrial dynamic balance and mitochondrial function. 4-PBA inhibited MAM formation mainly via decreasing the lactate production and lactylation of Arpc1b-K308 by inhibiting the glycolysis limiting enzyme HK2, and 4-PBA inhibited HK2 activity by binding K621 and K624 catalytic sites. Conclusions:The results indicate that 4-PBA protects cardiac function following sepsis by recovering mitochondrial dynamics balance. This finding provides a novel therapeutic strategy and potential target for SIMD.
The integrity of the intestinal mucosal barrier is essential for maintaining normal gut physiology, and its disruption is associated with a wide range of conditions, including trauma- and burn-related intestinal injury, which remain difficult to manage clinically. Intestinal organoid-on-a-chip systems have emerged as advanced in vitro models that reproduce key features of the intestinal microenvironment and physiological function. These systems have shown promise for studying mucosal injury and repair, assessing therapeutic strategies, and supporting translational research. This review summarizes the basic principles of intestinal organoid-on-a-chip technology and examines its use in modeling intestinal barrier function, inflammatory responses, drug screening, regenerative approaches, and trauma-related barrier repair. It also reviews recent progress in preclinical studies, considers potential applications in gastrointestinal research, and discusses current technical challenges, particularly those related to scalability and reproducibility. Future directions for the development of next-generation systems are also outlined. With the continued integration of advances across disciplines, these platforms may provide useful tools for studying and treating disorders involving the intestinal mucosal barrier, especially in the context of trauma and burns.
Background:Hypertrophic scars (HTSs) are characterized by excessive extracellular matrix deposition and impaired scar remodelling. Fibroblasts are central to HTS pathogenesis, yet clinical strategies remain limited by an incomplete understanding of fibroblast heterogeneity and transcriptional regulation. This study aimed to identify a key fibroblast subpopulation and its regulatory transcription factors to address this translational gap. Methods:Single-cell RNA sequencing was performed on dermal cells from freshly excised human HTS and normal skin (NS) tissues. Fibroblast subsets and transcriptional regulators were identified using Seurat, pseudotime, transcription factor prediction, and cell-cell communication analyses. Functional validation involved lentiviral overexpression of Yin Yang 1 (YY1) in fibroblasts derived from patients with hypertrophic scars, followed by bulk RNA sequencing, western blotting, CUT&Tag, and immunofluorescence assays. Results:Clinical HTS specimens showed characteristic collagen overproduction and vascular hyperplasia. Single-cell analysis of 43 303 cells revealed disease-specific shifts in cellular composition, including pronounced pericyte expansion and reduced fibroblast abundance. Notably, fibroblast subcluster Fib_5 (ADAM12+ COMP+ POSTNhi) increased despite the overall fibroblast decline in HTS and exhibited upregulated fibrotic gene expression. Cross-validation using combined public datasets comprising 21 samples indicated that the Fib_5-like subcluster is conserved across fibrotic conditions. Pseudotime analyses placed Fib_5 within an HTS-dominant branch, State 6; transcription factor prediction from branch-dependent differentially expressed genes identified YY1 as the only predicted transcription factor also differentially expressed in State 6. Functional validation showed that YY1 overexpression in fibroblasts derived from patients with HTS reversed fibrotic gene expression profiles, with Fib_5 identified as a primary responder by Scissor. CUT&Tag analysis validated these findings at the epigenomic level. Cell-cell communication analyses further revealed marked reprogramming of fibroblast-pericyte signalling across multiple fibrosis-related pathways in HTS. Conclusion:This work establishes the Fib_5-YY1 axis as a central hub in HTS pathogenesis, with YY1-mediated fibroblast plasticity as a key transcriptional mechanism underlying skin fibrogenesis.
