Preventing Engrailed-1 activation in fibroblasts yields wound regeneration without scarring

Promoting scarless wound closure utilizing an injectable thermosensitive hydrogel with anti-inflammatory, antioxidant, and scar formation inhibiting properties

Skin trauma, surgery, or burns can result in non-functional scar tissue, causing significant physiological and psychological harm to patients. Therefore, there is an urgent need for a treatment strategy that promotes rapid wound healing and suppresses scar formation. In this study, we developed a facile and injectable composite hydrogel system (PF-127@ERD) loaded with eriodictyol, which exhibits efficient sustained release of the scar-inhibiting compound at different stages of wound healing to facilitate rapid and scarless closure. Our findings revealed that PF-127@ERD not only stops bleeding and reduces local oxidative stress damage in skin wounds but also regulates the inflammatory microenvironment by inhibiting the expression of relevant inflammatory factors while promoting fibroblast migration. Furthermore, PF-127@ERD inhibits excessive collagen deposition and regulates the expression of genes associated with scar formation, thereby promoting scar-free wound healing. In a rat model of full-layer skin defects, skin wound tissue treated with PF-127@ERD healed faster, exhibited more orderly collagen alignment, and showed reduced scar tissue formation compared to other groups. This process may be due to its inhibition of ferroptosis-related pathways. Therefore, this straightforward hydrogel system based on the skin repair stage (PF-127@ERD) holds great potential for scarless wound healing.

Multifunctional hydrogel dressing composed of trichosanthes polysaccharide and carboxymethyl chitosan accelerates cachectic wound healing and reduces scar hyperplasia

Cancer cachexia affects up to 80 % of advanced cancer patients and contributes to significant mortality. Impaired wound healing in cachectic patients limits physical activity, leads to nutrient loss, and increases infection risk. This study develops multifunctional hydrogels composed of oxidized polysaccharides (TPS) from Radix Trichosanthis and carboxymethyl chitosan (termed CMOT) to enhance wound healing and mitigate scar hyperplasia. TPS, characterized by its immunomodulatory properties, was oxidized to create aldehyde derivatives (oTPS1 and oTPS2) with varying oxidation levels and crosslinked with carboxymethyl chitosan through Schiff base reactions to form hydrogels (CMOT1 and CMOT2). It indicates the ability to tailor the rheological and mechanical properties of CMOT hydrogels through controlled oxidation and cross-linking. These hydrogels exhibited excellent self-healing properties, biocompatibility, and immunoregulatory effects on macrophages and T lymphocytes. Notably, CMOT2 hydrogel, with higher aldehyde content, exhibited superior mechanical properties, enhanced water retention, and slower degradation than CMOT1, consequently, accelerating wound healing in cancer cachexia conditions and reducing scar hyperplasia. The therapeutic mechanisms were associated with promoting angiogenesis, collagen synthesis, and epithelial repair, while down-regulating En-1. It not only addresses the challenges of wound healing in cancer cachexia but also offers a potential therapeutic strategy for scar hyperplasia inhibition.

Bacterial colonization contributes to pathological scar formation via the regulation of inflammatory response

BACKGROUND

It has been established that inflammatory factors are involved in the formation of pathological scars. Therefore, pathological scars are regarded to be highly associated with chronic inflammation, whereas what factors contribute to this inflammation remains unclear.

OBJECTIVE

To confirm that bacterial colonization is involved in the formation of pathological scars, and to reveal that the persistent inflammatory response mediated by macrophages due to bacterial colonization promotes scar formation.

METHODS

This study included 23 normal skin controls and 58 untreated pathological scar samples. To detect the presence of bacteria in surgically-excised scar samples and alterations of histology, as well as bacteria-associated gene levels, histological staining, immunoelectron microscopy, microbiological and cell culture and molecular biology detection methods were employed. The PICRUSt2 tool and BugBase were employed to identify pathways, genes, and phenotypic differences.

RESULTS

We found that in pathological scars, bacteria were widely distributed both extracellularly and intracellularly, with intracellular bacteria primarily located in the cytoplasm of macrophages and fibroblasts. A total of 2,260 bacterial species were detected in pathological scars, primarily from the Clostridiales, Burkholderiales, Actinomycetales, and Bacteroidales orders. Moreover, the pathogenicity and motility of colonizing bacteria were positively correlated with the degree of scar hyperplasia and invasiveness. The lysates of four clinically-relevant bacterial species had differential effects on the secretion of inflammatory cytokines from macrophages. When treated macrophage supernatant was added to fibroblasts, collagen secretion was dysregulated, and fibroblast differentiation into myofibroblasts prominently increased. In rat scar model, the expression of inflammatory factors and growth factors in the scar tissue was increased, which activated the TGF-β/Smad signaling pathway, resulting in the increasing of α-SMA.

CONCLUSIONS

Persistent activation of macrophages by tissue-colonizing bacteria may be a key factor in promoting inflammatory response and dysregulated collagen deposition in pathological scars, offering a potential new strategy for preventing and treating pathological scars.

Transformative lactera-polypyrrole@carrageenan microparticles leveraging NIR for skin regeneration and stress relief

Effective wound healing remains a significant challenge in regenerative medicine, particularly in minimizing inflammation and promoting scarless recovery. This study introduces a bioengineered LAC-PPy@Car MF composite, designed to leverage near-infrared (NIR)-induced photothermal therapy alongside biotherapeutics to accelerate tissue regeneration. The composite integrates the photothermal properties of polypyrrole (PPy) with the anti-inflammatory and regenerative potential of Lactera (LAC) and Carrageenan (Car). Upon NIR activation, the composite generates localized mild-hyperthermia, reducing oxidative stress, enhancing Aryl Hydrocarbon Receptor (AhR) activity, and upregulating heat shock proteins (HSP). These effects synergistically create a bioactive environment conducive to cellular proliferation and tissue repair. Biochemical evaluations demonstrate that LAC-PPy@Car MF effectively reduces oxidative stress, stimulates fibroblast migration, and promotes the proliferation of skin cells. Immunofluorescence staining reveals significant activation of AhR and HSP in treated tissues, correlating with accelerated cellular proliferation and improved skin architecture. The NIR-triggered photothermal effect enhances the therapeutic potential of the composite, ensuring precise and minimally invasive treatment for burn injuries. These findings position phototherapeutic LAC-PPy@Car MF as a promising candidate for advanced wound healing applications. Its dual functionality, combining photothermal therapy with bioactive healing properties, offers a transformative approach to regenerative medicine, paving the way for improved clinical outcomes in wound care.

LncRNA SNHG1/miR-320b/CTNNB1 axis regulating the collective migration of fibroblasts in the formation of keloid

BACKGROUND

To explore the regulatory molecular mechanism of long non-coding RNA (lncRNA) small nucleolar RNA host gene 1 (SNHG1) expression on keloid formation.

METHODS

The expression differences of SNHG1, miR-320b, and Catenin Beta 1 (CTNNB1) in keloid tissue and normal skin tissue of patients with keloid were detected. Normal cultured human fibroblasts were used as the Blank group (Blank) and then transfected with si-SNHG1 to silence SNHG1 expression. MTT assay, Transwell chamber assay, RT-qPCR, and Western blot (WB) were used. SNHG1 and miR-320b, as well as miR-320b and CTNNB1, were found to be targeted using the dual luciferase reporter gene (DLRG) strategy.

RESULTS

As against normal skin tissue, SNHG1 and CTNNB1 were increased, while miR-320b was decreased in keloid tissue (P < 0.05). As against the Blank, there was a drop in the number of transferring and attacking cells, a decrease in the proliferative activity, an increase in the expression of miR-320b, a decrease in CTNNB1, and the relative expression (RE) of Pro-Collagen I, Cyclin D1, VEGF, α-smooth muscle actin (α-SMA), matrix metallopeptidase-2 (MMP-2), and MMP-9 was decreased in the si-SNHG1 group (AG) (P < 0.05).

CONCLUSION

SNHG1 could target and regulate miR-320b, and miR-320b could target and regulate CTNNB1. Fibroblast transfer, attack, and multiplication may all be prevented by reducing SNHG1 expression.

Gene-engineered polypeptide hydrogels with on-demand oxygenation and ECM-cell interaction mimicry for diabetic wound healing

The treatment of infected diabetic wounds remains a significant clinical challenge due to pathogen infection, excessive inflammation, and impaired angiogenesis with troubled extracellular matrix (ECM) - cell and cell - cell interaction. Herein, we prepared a Janus polypeptide-engineered hydrogel with programmable function driven by self-assembly of the same A domain. The hydrogel was composed of a V8-degradable AC10A layer loaded with hybrid phages (ABC) for precise bacterial inhibition and a PC10ARGD layer loaded with Mn-based mineralized erythrocyte (PEM) for continuous supply oxygen on demand. The results of laser speckle contrast imaging, photoacoustic imaging, and hyperspectral imaging demonstrated that the AC10A@BP-Ce6/PC10AR@EM hydrogel (ABC/PEM) accelerated the reconstruction of normal skin structure by breaking the oxygen diffusion barrier and supplying oxygen on demand to promote angiogenesis and functionalization. In addition, in vitro and in vivo experiment results showed that the ABC/PEM hydrogel can mimic positive ECM - cell interaction to inhibit the polarization of macrophage towards M1-type to slow down the inflammatory process by down-regulated yes-associated protein (YAP), and relieve the mechanical tension of fibroblasts and keratinocytes. Finally, the ABC/PEM hydrogel promotes a healing rate of 98.83 % on day 21 and results in the number of dermal appendages being eight times that of the negative group. This work presents an effective strategy for diabetes-related chronic infected wound management.

Functionalized gelatin/poly(l-lactide-co-ε-caprolactone) fibrous membrane promotes scarless wound healing by modulating inflammation and reducing fibrosis

In cases of deep skin defects, spontaneous tissue regeneration and excessive collagen deposition can result in the formation of proliferative scarring. Salvianolic acid B (SAB) demonstrates promising applications in the treatment of fibrotic diseases, including scarring. This study prepared biodegradable gelatin (Gel) and poly(lactic-co-ε-caprolactone) (PLCL) nanofibrous membranes using electrospinning technology and functionalized them with salvianolic acid B to create fibrous membrane dressings with anti-scarring properties. The resulting Gel/PLCL/SAB (GPS) fibrous membrane exhibited good mechanical properties and biodegradability. In vitro experiments demonstrated that the fibrous membranes of Gel/PLCL containing 0.5 wt% SAB (GPS0.5) exhibited good cytocompatibility, regulated macrophage function and polarization, and inhibited fibrosis-related genes, including CD36, α-SMA, and collagen I. In a mouse model of full-thickness skin defects, the GPS0.5 fibrous membrane effectively modulated the immune microenvironment and promoted vascular regeneration, thereby accelerating skin healing. Furthermore, the GPS0.5 fibrous membrane reduced the expression of CD36 and TGF-β1, downregulated collagen I and III, and promoted the regeneration of hair follicles, sebaceous glands, and other appendages, ultimately reducing scar formation. Thus, SAB-loaded Gel/PLCL fibrous membranes hold potential as bifunctional skin dressings that promote wound healing and inhibit fibrosis.

RGD peptide hydrogel downregulates mechanosignal YAP to inhibit postoperative scarring

OBJECTIVE

Glaucoma filtration failure may result from an overabundance of human Tenon's capsule fibroblasts (HTFs) forming a filtration tract scar. Conversely, the Yes-associated protein (YAP), a transcriptional activator of the Hippo signaling pathway, is a crucial matrix stiffness regulator of matrix production and fibroblast activation. With superior biocompatibility and biodegradability, RGD peptide hydrogels imitate the structure of real tissues' extracellular matrix (ECM). The purpose of this research was to determine whether down-regulating YAP expression via RGD peptide hydrogels may prevent HTFs activation and ECM protein secretion. Transforming growth factor-β2 (TGF-β2) was used to induce the activation of HTFs in a cellular model of scarring following glaucoma filtration surgery. Utilizing SD rats, a murine model of subconjunctival injury was established. The shape of collagen fibers was observed through Masson staining, and the expression of YAP and α-smooth muscle actin (α-SMA) was identified through immunohistochemistry. RGD peptide hydrogel was discovered to have anti-scarring properties in a mouse eye injury model, as well as the ability to lessen HTFs activation, YAP expression, cytosolic nucleus accumulation, and the expression of connective tissue growth factor (CTGF) and ECM proteins. The best concentration was found to be 1.0 weight percent among them. This concentration not only makes it easier to inject a drug subconjunctivally in vivo and maintain the filtration vesicle space in the conjunctiva, but it also inhibits the activation of fibroblasts into myofibroblasts and down-regulates the expression of the Hippo-YAP signaling pathway in Tenon's capsule fibroblasts.

STATEMENT OF SIGNIFICANCE

1. The homogenous reticular three-dimensional nanostructure that made up the interior structure of the 1.0 weight percent gel had good drug delivery characteristics for long-lasting controlled drug release. 2. RGD peptide hydrogel had a certain matrix hardness, which could mimic the normal connective tissue hardness under the conjunctiva. 3. RGD peptide hydrogels could prevented the development of rat conjunctival fibrosis. 4. RGD peptide hydrogel could inhibit the expression of YAP and its target gene CTGF, as well as α-SMA, ECM proteins in HTFs. 5. RGD peptide hydrogel has good biocompatibility, biodegradability, and stable mechanical properties, and can also be used as a promising carrier for the controlled release of drugs.

Temperature-Programmable Deformable Microneedles for Scar-Free Healing of Infective Wounds via Sensory Nerve Regeneration

Infectious wound healing remains a complex challenge, complicated by bacterial infections, inflammation, and sensory nerve damage, which hinder healing and contribute to excessive scarring. For refractory wound healing, a temperature-programmable deformable microneedle (TPDM) is constructed, which can program at 85 °C through changes in time to maintain the shape for a corresponding period of time at 27 °C before returning to its original shape. In addition, his deformation is not temperature related, but rather caused by the separation of water phases to prevent skin burns from high temperatures and secondary impacts. The microneedles are characterized using scanning electron microscopy, transmission electron microscopy, and Nile red staining. Their antibacterial efficacy is confirmed through co-culture with methicillin-resistant Staphylococcus aureus (MRSA). In vitro, it promoted keratinocyte migration and facilitated sensory nerve regeneration. Furthermore, they significantly reduced scar-associated Engrailed-1 (EN-1)-positive fibroblasts and macrophages, which are key contributors to fibrotic responses. In vivo, it accelerated wound healing, reduced the accumulation of EN-1-positive fibroblasts and collagen I, and enhanced sensory nerve density and mitochondrial activity at the wound site. TPDM exhibits strong antibacterial properties against MRSA, promoting sensory nerve regeneration and reduces scarring, offering a promising therapeutic strategy for improving the healing of infectious wounds.

Enhanced Closed Incisional Negative Pressure Therapy for Treating Infectious Scars

Background

Chronic infectious pathological scars, characterized by mutual reinforcement between infection and pathological scarring, pose challenges in reconstructive surgery. We introduce an enhanced closed incisional negative pressure therapy following a 1-stage surgery to simultaneously eradicate infection and alleviate wound tension.

Methods

A total of 25 patients who underwent chronic infectious pathological scar treatment by using this enhanced closed incisional negative pressure therapy were retrospectively reviewed. The outcomes were evaluated by postoperative recurrence frequency of infection and scarring during a 1-year follow-up, as well as the Patient and Observer Scar Assessment Scale and quality-of-life scores.

Results

After treatment, no serious complications, such as incision dehiscence, occurred. The average wound healing time was 12.68 days. Only 1 patient experienced surgical site scarring. Besides, average infection frequency decreased significantly from 6.40 to 0.00 times per year (P < 0.0001). The Patient and Observer Scar Assessment Scale score decreased from 81.60 to 25.36 (P < 0.0001), whereas the quality-of-life score increased from 2.20 to 4.88 (P < 0.0001).

Conclusions

The enhanced closed incisional negative pressure therapy effectively facilitated infectious wound healing in a 1-stage operation and simultaneously prevented infection and scarring recurrence in long-term follow-up, resulting in satisfactory postoperative outcomes.

ACKR3 in Skin Homeostasis, an Overlooked Player in the CXCR4/CXCL12 Axis

CXCL12 and its receptor CXCR4 emerge as critical regulators within the intricate network of processes ensuring skin homeostasis. In this review, we discuss their spatial distribution and function in steady-state skin; delve into their role in acute wound healing, with emphasis on fibrotic and regenerative responses; and explore their relevance in skin responses to commensals and pathogens. Given the lack of knowledge surrounding ACKR3, the atypical receptor of CXCL12, we speculate whether and how it might be involved in the processes mentioned earlier. Is ACKR3 the (a)typical friend who enjoys missing the party, or do we need to take a closer look?

Histological signatures map anti-fibrotic factors in mouse and human lungs

Fibrosis, the replacement of healthy tissue with collagen-rich matrix, can occur following injury in almost every organ1,2. Mouse lungs follow a stereotyped sequence of fibrogenesis-to-resolution after bleomycin injury3, and we reasoned that profiling post-injury histological stages could uncover pro-fibrotic versus anti-fibrotic features with functional value for human fibrosis. Here we quantified spatiotemporally resolved matrix transformations for integration with multi-omic data. First, we charted stepwise trajectories of matrix aberration versus resolution, derived from a high-dimensional set of histological fibre features, that denoted a reversible transition in uniform-to-disordered histological architecture. Single-cell sequencing along these trajectories identified temporally enriched 'ECM-secreting' (Csmd1-expressing) and 'pro-resolving' (Cd248-expressing) fibroblasts at the respective post-injury stages. Visium-based spatial analysis further suggested divergent matrix architectures and spatial-transcriptional neighbourhoods by fibroblast subtype, identifying distinct fibrotic versus non-fibrotic biomolecular milieu. Critically, pro-resolving fibroblast instillation helped to ameliorate fibrosis in vivo. Furthermore, the fibroblast neighbourhood-associated factors SERPINE2 and PI16 functionally modulated human lung fibrosis ex vivo. Spatial phenotyping of idiopathic pulmonary fibrosis at protein level additionally uncovered analogous fibroblast subtypes and neighbourhoods in human disease. Collectively, these findings establish an atlas of pro- and anti-fibrotic factors that underlie lung matrix architecture and implicate fibroblast-associated biological features in modulating fibrotic progression versus resolution.

LA-peptide Hydrogel-Regulation of macrophage and fibroblast fates and their crosstalk via attenuating TGF-β to promote scarless wound healing

The homeostasis of the wound microenvironment is fundamental for scarless wound healing, while the excessive accumulation of transforming growth factor-beta (TGF-β) in the wound microenvironment always leads to hypertrophic scars (HS) formation by regulating cell fates and crosstalk among various types of cells, such as macrophages and fibroblasts. This study reports that an injectable, self-assembling LA-peptide hydrogel has the potential to facilitate scarless cutaneous wound healing through dynamically adsorbing TGF-β within the wound environment. We found that the released LA peptides led to the suppression of both the PI3K/Akt and TGF-β/Smad2/3 pathways in macrophages and fibroblasts. As expected, the application of LA-peptide hydrogel alleviated the M2 type polarization of macrophages and inhibited fibroblasts activation by adsorbing TGF-β both in vitro and in vivo. Furthermore, designated concentrations of the LA-peptide hydrogel achieved controlled release of LA peptides, enabling dynamic regulation of TGF-β for maintaining microenvironment homeostasis during different phases of wound healing. This contributed to the inhibition of HS formation without delaying wound healing in both a mouse full-thickness skin wound model and a rabbit ear scar model. Overall, the LA-peptide hydrogel provides promising avenues for promoting scarless healing of wounds, exemplifying precision medicine-guided targeting of specific pathogenic molecules, such as TGF-β, and highlighting the significance of dynamic regulation of TGF-β homeostasis in wound microenvironment.

A transient contractile seam promotes epithelial sealing and sequential assembly of body segments

In embryos, epithelial sealing proceeds with progressive zipping eventually leading to a scar-free epithelium and ensuring the assembly of body segments in insects and neural tube in mammals. How zipping is mechanically controlled to promote tissue fusion on long distances, remains unclear. Combining physical modeling with genetic and mechanical perturbations, we reveal the existence of a transient contractile seam that generates forces to reduce the zipping angle by force balance, consequently promoting epidermal sealing during Drosophila embryogenesis. The seam is formed by the adhesion of two tissues, the epidermis and amnioserosa, and is stabilized by the tensions generated by the segment boundaries. Once a segment is zipped, the seam disassembles concurrently with the inactivation of the Jun kinase pathway. Thus, we show that epithelial sealing is promoted by a transient actomyosin contractile seam allowing sequential segment assembly.

Piezo1-Mediated Calcium Flux Transfers Mechanosignal to YAP to Stimulate Matrix Production in Keloid

Keloids are fibroproliferative diseases affecting millions worldwide, but curing keloids remains challenging. Mechanical force is a common initiator and driver of keloids, and blocking the pro-adhesive signaling pathways is expected to cure keloids. This study found higher levels of Piezo1 in human keloid fibroblasts (KFbs) compared with normal skin fibroblasts (Fbs). Single-cell transcriptome analysis revealed a correlation of Piezo1 with YAP in KFbs. Knockdown of Piezo1/YAP in KFbs versus Fbs decreased CCN2 and CCN1 expression and fibrosis-related cell behaviors, identifying Piezo1 and YAP as upstream signals of pro-adhesive signaling loop in keloids. Treatment of patient-derived keloid xenograft model with Piezo1 inhibitor GsMTx4 and YAP inhibitor Verteporfin reduced keloid volume and decreased type I/III collagen ratio. Atomic force microscopy further confirmed the biomechanical improvements of keloids in elasticity, viscoelasticity, and roughness ex vivo. In addition, the Ca2+-sensitive fluorescent indicator Fluo-3/AM and double-labelling immunofluorescence stains showed Piezo1 transferred mechanosignal to increase YAP nuclear translocation via calcium flux. Finally, transcriptomics revealed target genes of the Piezo1/YAP signaling pathway, such as TBX3, SESN2, SMAD7, FOSB, JARID2, and HAS2. Consequently, the Piezo1/calcium flux/YAP signaling axis contributes to the mechanically induced pro-adhesive signaling pathway, and thus, Piezo1 and YAP are promising targets for keloid treatment.

Research progress on the role of fascia in skin wound healing

The skin, the human body's largest organ, is perpetually exposed to environmental factors, rendering it vulnerable to potential injuries. Fascia, a vital connective tissue that is extensively distributed throughout the body, fulfils multiple functions, including support, compartmentalization, and force transmission. The role of fascia in skin wound healing has recently attracted considerable attention. In addition to providing mechanical support, fascia significantly contributes to intercellular signalling and tissue repair, establishing itself as a crucial participant in wound healing. This review synthesises the latest advancements in fascia research and its implications for skin wound healing.

Repurposing verteporfin and hyaluronic acid gel for ocular surface treatment to prevent corneal scarring

There is an unmet need for point-of-care therapies to prevent scarring and promote corneal clarity after injury, which is essential for maintaining vision. Verteporfin, an inhibitor of Yes-associated protein (YAP), has been shown to prevent fibrosis in several organs. Visudyne (VP) is an FDA-approved liposomal formulation of verteporfin used to treat abnormal blood vessels in the eye. Here, we showed that VP reduces myofibroblast formation in corneal stromal fibroblasts. To prolong the residence time of verteporfin on the ocular surface, the cohesive viscoelastic ProVisc® hyaluronic acid (HA) gel was hybridized to VP. This formulation is readily translatable because both VP and ProVisc® HA gel are FDA-approved agents. The ProVisc® HA gel increased the residence of subconjunctivally injected verteporfin 12-fold at 24 h after injection compared with pure VP. A single subconjunctival administration of VP hybridized within ProVisc® HA gel (VP/HA hydrogel) significantly reduced YAP activation, corneal fibrosis, neovascularization, and inflammation, leading to reduced opacity without compromising epithelial wound healing in mechanically injured rat corneas. This work demonstrated that VP hybridized with a viscoelastic HA gel can be readily repurposed to promote scar-less healing in the cornea.

Effects of Verteporfin on Interstitial Fluid Flow-Induced Fibrotic Transdifferentiation of Human Tenon Fibroblasts

Purpose

Postoperative scarring remains the major challenge in achieving long-term success after glaucoma filtration surgery. In a previous study, we showed that slow continuous fluid flow is sufficient to induce fibrotic responses in human tenon fibroblasts (HTFs) in two-dimensional (2D) and three-dimensional (3D) in vitro models. In the present study, we investigated the role of the mechanosensitive Yes-associated protein (YAP) and transcriptional coactivator (TAZ) signaling pathway in flow-induced fibrosis.

Methods

HTFs were exposed to continuous fluid flow for 48 or 72 hours in the presence or absence of the YAP/TAZ-transcriptional enhanced associated domain inhibitor verteporfin (VP). In a 2D model, the F-actin cytoskeleton, fibronectin 1 (FN1), YAP, and TAZ were visualized by confocal immunofluorescence microscopy. In a 3D model, mRNA was extracted, and the expression of fibrosis-associated genes was detected by quantitative PCR.

Results

HTFs exposed to slow fluid flow showed increased staining intensities for YAP/TAZ. Inhibition of YAP/TAZ by VP slightly reduced flow-induced fibrotic changes in the 2D model. The flow-induced increase in the expression of the extracellular matrix (ECM) genes COL1A1, CTGF, and FN1 was significantly inhibited by VP in the 3D model.

Conclusions

Slow interstitial fluid flow activates the YAP/TAZ pathway. VP exerts antifibrotic potential by reducing morphologic changes and suppressing the expression of ECM genes induced by flow. Therefore, YAP/TAZ inhibition may exhibit therapeutic potential after glaucoma filtration surgery by inhibiting fibrotic changes induced by mechanical stimuli.

Dual-Action flavonol carbonized polymer dots spray: Accelerating burn wound recovery through immune responses modulation and EMT induction

Effective immune homeostasis modulation and re-epithelialization promotion are crucial for accelerating burn wound healing. Cell migration is fundamental to re-epithelialization, with epithelial-mesenchymal transition (EMT) as a key mechanism. A sustained inflammatory environment or impaired macrophage transition to M2 phenotype can hinder pro-resolving cytokine activation, further delaying the recruitment, migration, and re-epithelialization of epidermal cells to the injury site, ultimately compromising wound healing. Herein, the bioactive flavonol quercetin is transformed into pharmacologically active carbonized polymer dots (Qu-CDs) spray with high water dispersibility, permeability and biocompatibility for full-thickness skin burns treatment. Qu-CDs spray can efficiently initiate macrophage reprogramming and promote the transition of macrophages from M1 to M2 phenotype, modulating immune responses and facilitating the shift from the inflammatory phase to re-epithelialization. Additionally, Qu-CDs spray can promote cell migration and re-epithelialization of wound edge epithelial cells by inducing an EMT process without growth factors, further accelerating the reconstruction of the normal epidermal barrier. Mechanistically, Qu-CDs spray activates the smad1/5 signaling pathway for promoting the EMT phenotype of wound edge epithelial cells. Overall, this study facilitates the construction of novel spray dosage form of pharmacologically active carbonized polymer dots with desired bioactivities for effective wound healing.

Histamine receptor agonism differentially induces immune and reparative healing responses in biomaterial-facilitated tissue repair

Tissue repair is a highly regulated process involving immune, stromal, vascular, and parenchymal cell responses. Mediators of cellular responses at different phases of the healing process stimulate transitions through the continuum of repair. Histamine is an early mediator of healing, which, in skin, is released by resident cells (e.g., mast cells) after cutaneous injury, and acts to stimulate diverse responses in multiple cell populations. Histamine signaling is regulated by four distinct cell surface G-protein coupled receptors (HRH1-4 in humans, Hrh1-4 in mice) which initiate different downstream signaling cascades upon activation, but the specific effect of each receptor on tissue repair is poorly understood. Here, we systematically investigated the effect of selective histamine receptor agonism in laser-activated sealing and tissue repair of incisional skin wounds in immunocompetent mice. Although all four histamine receptors exhibited wound responsiveness in the epidermis, we find that activation of Hrh1, Hrh2, and Hrh4 stimulate a pro-healing immune response characterized by increased pro-resolution macrophages, reduced pro-inflammatory macrophages, and suppressed neutrophil responses. Further, activation of Hrh1 and Hrh4 stimulate angiogenesis after injury. Lastly, although Hrh1 activation resulted in enhanced epidermal epithelial-to-mesenchymal transition (EMT) in vivo and epithelialization in vitro, activation of Hrh2 suppressed both epidermal EMT and epithelialization. Activation of Hrh3, primarily found on neuronal cells, had no effect on any measure in our study. Selective histamine receptor agonism, specifically of histamine receptors Hrh-1 and 4, is a potential reparative approach to promote the efficacy of biomaterial-mediated repair of tissues, including skin.

Osteopontin attenuates the foreign-body response to silicone implants

The inflammatory process resulting in the fibrotic encapsulation of implants has been well studied. However, how acellular dermal matrix (ADM) used in breast reconstruction elicits an attenuated foreign-body response (FBR) remains unclear. Here, by leveraging single-cell RNA-sequencing and proteomic data from pairs of fibrotically encapsulated specimens (bare silicone and silicone wrapped with ADM) collected from individuals undergoing breast reconstruction, we show that high levels of the extracellular-matrix protein osteopontin are associated with the use of ADM as a silicone wrapping. In mice with osteopontin knocked out, FBR attenuation by ADM-coated implants was abrogated. In wild-type mice, the sustained release of recombinant osteopontin from a hydrogel placed adjacent to a silicone implant attenuated the FBR in the absence of ADM. Our findings suggest strategies for the further minimization of the FBR.

Current Best Evidence for 5 Promising Medications Used for Scar Minimization Therapy

Introduction: Wound healing by fibrosis allows for closure of a wound, but leaves behind a permanent scar with physical and psychological effects. The primary aim of this narrative review was to summarize the current status of the evidence supporting the use of oral or topical medications to minimize scarring in humans. Methods: With the help of a health sciences librarian, PubMed, Embase, and Scopus were searched up to March 31, 2023, to investigate potential medications to ameliorate scarring. Based on this search, the medications pirfenidone, losartan, trichostatin A, enalapril, and atorvastatin were identified as 5 therapies with the most research to support their use. Studies discussing noncutaneous scarring (myocardial, intraabdominal, etc) or in animal models were excluded. Results: There is a paucity of quality literature describing the use of oral or topical medications to minimize fibrosis and produce more favorable scarring. Six studies describing the medications listed above all demonstrated an improvement in scarring parameters, most commonly based on the Vancouver Scar Scale. Conclusions: Though preliminary, emerging evidence suggests that therapies already exist with the potential to improve cutaneous scarring. Some of these medications are already ubiquitous, affordable and have a known safety profile. Excitingly, these treatments are either oral or topical, meaning that they are more accessible for patients than some current modalities for scar treatment, including steroid injections or laser therapy. Further larger-scale trials are needed before these treatments can be recommended as a routine part of scar management.

Postoperative adhesions are abrogated by a sustained-release anti-JUN therapeutic in preclinical models

Postoperative abdominal adhesions are the leading cause of bowel obstruction and a cause of chronic pain and infertility. Adhesion formation occurs after 50 to 90% of abdominal operations and has no proven preventative or treatment strategy. Abdominal adhesions derive primarily from the visceral peritoneum and are composed of polyclonally proliferating tissue-resident fibroblasts. We have previously shown that signaling of the transcription factor JUN regulates adhesiogenesis and that a small-molecule JUN inhibitor (T-5224) decreases adhesion formation. Here, we encapsulated T-5224 in a shear-thinning hydrogel with antiadhesion properties for intraperitoneal postoperative delivery and sustained release of a JUN inhibitor for adhesion prevention. The material properties of the T-5224-hydrogel support its use for open or minimally invasive surgical application. We found this therapeutic system to be safe, well tolerated, and efficacious in murine and porcine preclinical models. T-5224-hydrogel minimized adhesion quantity and also diminished adhesion fibrosis at an ultrastructural level. Moving toward clinical translation, we developed a large mammal adhesion model in pigs with bowel resection. Single-cell transcriptomic analysis showed that JUN and associated pathway signaling were diminished in adhesion-derived fibroblasts treated with T-5224-hydrogel. The JUN-inhibiting T-5224-hydrogel provided robust prevention of adhesion without deleterious effects on bowel anastomosis or abdominal wall healing. Adhesion biology is similar across surgical sites, and, therefore, this formulation has potential for applicability across the body. The development of therapeutics to prevent adhesions is of paramount importance with potential for high-impact translation to patient care to address a common, unmet clinical need.

Ursolic Acid Inhibits Collagen Production and Promotes Collagen Degradation in Skin Dermal Fibroblasts: Potential Antifibrotic Effects

Tissue fibrosis, characterized by excessive collagen accumulation, leads to impaired organ function and is a hallmark of various chronic diseases. Fibroblasts play a central role in collagen production and deposition. This study examines the impact of ursolic acid, a pentacyclic triterpenoid compound present in various fruits and vegetables, on collagen homeostasis in primary human dermal fibroblasts. Ursolic acid (UA) was observed to significantly reduce collagen production while markedly increasing the activity of matrix metalloproteinase-1 (MMP-1), an enzyme responsible for collagen degradation. Mechanistically, ursolic acid was found to inhibit TGF-β/Smad signaling, leading to decreased collagen production, and to activate mitogen-activated protein kinase (MAPK) pathways and activator protein 1 (AP-1), resulting in enhanced MMP-1 production. These in vitro findings were further validated in an in vivo mouse model of fibrosis, where ursolic acid significantly mitigated bleomycin-induced skin fibrosis. These results suggest that UA could be a promising candidate for treating skin fibrosis due to its dual effects on collagen homeostasis: inhibiting collagen production and promoting collagen degradation.

Electroactive Asymmetric Dressing for Spatiotemporal Deep Burn Scarless Healing and Management

Burn care and treatment differ markedly from other types of wounds, as they are significantly more prone to infections and struggle to maintain fluid balance post-burn. Moreover, the limited self-healing abilities exacerbate the likelihood of scar formation, further complicating the recovery process. To tackle these issues, an asymmetric wound dressing comprising a quercetin-loaded poly(3-hydroxybutyrate-co-4-hydroxybutyrate) (P34HB@Qu) hydrophilic layer and a zinc oxide nanoparticle-loaded, thermally treated polyvinylidene fluoride (HPVDF@ZnO) hydrophobic layer is designed. This dressing provided antibacterial property and exudate management in the early stages of burn treatment, preventing infection and maintaining moisture balance at the wound site. As healing progresses, the electroactive properties of HPVDF@ZnO and quercetin from P34HB@Qu synergistically regulate cell migration and differentiation, accelerating wound healing and facilitating scar-free regeneration. Furthermore, the wound dressing assisted in the regeneration of skin appendages. This study underscores the full-cycle strategy of versatile wound dressings for spatiotemporal burn wound management from injury to scarless healing.

Targeting TEAD would be a potential strategy for scarless wound repair: A preliminary study

Despite of decades of efforts, novel approaches are still limited to attenuate or prevent skin scarring. A previous report published in Science demonstrated that inhibition of YAP promotes scarless wound repair by regeneration. Due to the difficult drugability of targeting YAP, we speculated that inhibition of TEAD, a partner molecule of YAP, might exist similar therapeutic potential. Therefore, the aim of the study was to evaluate therapeutical effect of a novel inhibitor of TEAD auto-palmitoylation, VT107, on scar formation in a cutaneous wound healing model. Our findings confirmed VT107 exhibited favorable effect on preventing scarring, manifesting as reducing fibroblast proliferation and collagen denaturation, decreasing TGF-β1 and collagen deposition, as well as connective tissue growth factor (CTGF) expression. These findings provide a novel insight for the development of anti-scarring strategies. TEAD would become an ideal target for the treatment of scars.

Wnt signaling modulates mechanotransduction in the epidermis to drive hair follicle regeneration

Most wounds form scars without hair follicles. However, in the wound-induced hair neogenesis (WIHN) model of skin regeneration, wounds regenerate hair follicles if tissue rigidity is optimal. Although WIHN depends on Wnt signaling, whether Wnt performs a mechanoregulatory role that contributes to regeneration remains uncharacterized. Here, we demonstrate that Wnt signaling affects mechanosensitivity at both cellular and tissue levels to drive WIHN. Atomic force microscopy revealed an attenuated substrate rigidity response in epidermal but not dermal cells of healing wounds. Super-resolution microscopy and nanoneedle probing of intracellular compartments in live human keratinocytes revealed that Wnt-induced chromatin remodeling triggers a 10-fold drop in nuclear rigidity without jeopardizing the nucleocytoskeletal mechanical coupling. Mechanistically, Wnt signaling orchestrated a massive reorganization of actin architecture and recruited adherens junctions to generate a mechanical syncytium-a cohesive contractile unit with superior capacity for force coordination and collective durotaxis. Collectively, our findings unveil Wnt signaling's mechanoregulatory role that manipulates the machinery of mechanotransduction to drive regeneration.

Inhibiting mechanotransduction prevents scarring and yields regeneration in a large animal model

Modulating mechanotransduction by inhibiting yes-associated protein (YAP) in mice yields wound regeneration without scarring. However, rodents are loose-skinned and fail to recapitulate key aspects of human wound repair. We sought to elucidate the effects of YAP inhibition in red Duroc pig wounds, the most human-like model of scarring. We show that one-time treatment with verteporfin, a YAP inhibitor, immediately after wounding is sufficient to prevent scarring and to drive wound regeneration in pigs. By performing single-cell RNA sequencing (scRNA-seq) on porcine wounds in conjunction with spatial proteomic analysis, we found perturbations in fibroblast dynamics with verteporfin treatment and the presence of putative pro-regenerative/profibrotic fibroblasts enriched in regenerating/scarring pig wounds, respectively. We also identified differences in enriched myeloid cell subpopulations after treatment and linked this observation to increased elaboration of interleukin-33 (IL-33) in regenerating wounds. Finally, we validated our findings in a xenograft wound model containing human neonatal foreskin engrafted onto nude mice and used scRNA-seq of human wound cells to draw parallels with fibroblast subpopulation dynamics in porcine wounds. Collectively, our findings provide support for the clinical translation of local mechanotransduction inhibitors to prevent human skin scarring, and they clarify a YAP/IL-33 signaling axis in large animal wound regeneration.

A postzygotic GNA13 variant upregulates the RHOA/ROCK pathway and alters melanocyte function in a mosaic skin hypopigmentation syndrome

The genetic bases of mosaic pigmentation disorders have increasingly been identified, but these conditions remain poorly characterised, and their pathophysiology is unclear. Here, we report in four unrelated patients that a recurrent postzygotic mutation in GNA13 is responsible for a recognizable syndrome with hypomelanosis of Ito associated with developmental anomalies. GNA13 encodes Gα13, a subunit of αβγ heterotrimeric G proteins coupled to specific transmembrane receptors known as G-protein coupled receptors. In-depth functional investigations revealed that this R200K mutation provides a gain of function to Gα13. Mechanistically, we show that this variant hyperactivates the RHOA/ROCK signalling pathway that consequently increases actin polymerisation and myosin light chains phosphorylation, and promotes melanocytes rounding. Our results also indicate that R200K Gα13 hyperactivates the YAP signalling pathway. All these changes appear to affect cell migration and adhesion but not the proliferation. Our results suggest that hypopigmentation can result from a defect in melanosome transfer to keratinocytes due to cell shape alterations. These findings highlight the interaction between heterotrimeric G proteins and the RHOA pathway, and their role in melanocyte function.

Out of this World: Wound Healing on Earth and in Space

Impaired wound healing is a significant concern for humans in space, where the unique microgravity environment poses challenges to the natural healing processes of the body. Similar to chronic wounds on earth, such as diabetic foot ulcers and venous leg ulcers, wounds inflicted in space exhibit delayed or impaired healing responses. These wounds share common features, including dysregulated cellular signaling, altered cytokine profiles, and impaired tissue regeneration. Little is known about the mechanisms underlying wound healing under microgravity. In this review, we focused on exploring the parallels between wound healing in space and chronic wounds on earth as a fundamental approach for developing effective countermeasures to promote healing and mitigate associated health risks during long-space missions.

Spiny mice (Acomys) have evolved cellular features to support regenerative healing

Spiny mice (Acomys spp.) are warm-blooded (homeothermic) vertebrates whose ability to restore missing tissue through regenerative healing has coincided with the evolution of unique cellular and physiological adaptations across different tissue types. This review seeks to explore how these bizarre rodents deploy unique or altered injury response mechanisms to either enhance tissue repair or fully regenerate excised tissue compared to closely related, scar-forming mammals. First, we examine overall trends in healing Acomys tissues, including the cellular stress response, the ability to activate and maintain cell cycle progression, and the expression of certain features in reproductive adults that are normally associated with embryos. Second, we focus on specific cell types that exhibit precisely regulated proliferation to restore missing tissue. While Acomys utilize many of the same cell types involved in scar formation, these cells exhibit divergent activation profiles during regenerative healing. Considered together, current lines of evidence support sustained deployment of proregenerative pathways in conjunction with transient activation of fibrotic pathways to facilitate regeneration and improve tissue repair in Acomys.

Piezoelectric nanocomposite electrospun dressings: Tailoring mechanics for scar-free wound recovery

Rational wound management and enhancing healing quality are critical in clinical practice. Electrical stimulation therapy (EST) has emerged as a valuable adjunctive treatment due to its safety and cost-effectiveness. Integrating piezoelectric materials into dressings offers a way to miniaturize and personalize electrotherapy, enhancing convenience. To address the impact of physical factors of dressings on wound healing, a nanocomposite piezoelectric electrospun dressing using poly(L-lactic acid) (PLLA) and barium titanate (BaTiO3) was developed. We intentionally exaggerated design flaws to mimic the characteristics of scar extracellular matrix (ECM), including the oriented thick fibers and high Young's modulus. Initially, these dressings promoted fibrosis and hindered functional regeneration. However, when the piezoelectric effect was triggered by ultrasound, the fibrotic phenotype was reversed, leading to scar-free healing with well-regenerated functional structures. This study highlights the significant therapeutic potential of piezoelectric dressings in skin wound treatment and underscores the importance of carefully designing the static physical properties of dressings for optimal efficacy.

The Role of Fibroblasts in Chronic Inflammatory and Proliferative Skin Diseases

Fibroblasts (FBs) are crucial mesenchymal cells that preserve the skin's natural structure and physiological processes. They can build dense connective tissue by remodelling the extracellular matrix (ECM) and control immunological activity by secreting cytokines. This indicates that the development of chronic inflammatory and proliferative skin disorders is significantly influenced by fibroblasts. In order to provide new ideas for clinical research and treatment with a clearer perspective, this study thoroughly compiles the involvement of fibroblasts in various chronic inflammatory and proliferative skin diseases such as psoriasis, hypertrophic scar (HS), keloid, atopic dermatitis (AD), oral lichen planus (OLP), chronic eczema, and rosacea.

Skin Microbiota and Pathological Scars: A Bidirectional Two-Sample Mendelian Randomization Study

BACKGROUND

Pathological scars (PSs), resulting from abnormal skin repair, chronic inflammation, and fibrosis, affect millions of people. Previous studies have demonstrated that skin microbiota (SM) plays a role in cutaneous inflammation and healing, but the interplay between PSs and SM remains unclear yet.

OBJECTIVE

To investigate the causal associations between SM and two specific PSs: hypertrophic scars (HSs) and keloids.

METHODS

A bidirectional two-sample mendelian randomization (MR) analysis using genetic data for SM, HS, and keloids was conducted. The random-effects inverse variance weighted (IVW) method was used as the primary approach, along with multiple MR methods. False discovery rate (FDR) correction was employed to address multiple testing.

RESULTS

In forward analysis, the family Moraxellaceae and order Pseudomonadales exhibited the same significant protective effects on keloids (odds ratio [OR]: 0.849, 95% confidence interval [CI]: 0.770-0.935, q2 = 0.03626). The class Betaproteobacteria (OR: 0.938, 95% CI: 0.894-0.985, q1 = 0.01965) and genus Bacteroides (OR: 0.928, 95% CI: 0.884-0.973, q1 = 0.00889) each demonstrated a suggestive protective effect on HSs and keloids, respectively. Some limited evidence suggested that order Actinomycetales contributes to an increased risk of keloids. In reverse analysis, keloids were found to have negative effects on the class Gammaproteobacteria with limited evidence. There was no detectable evidence of horizontal pleiotropy or heterogeneity.

CONCLUSION

This study provided evidence for the causalities between SM and PSs, which laid foundation for furthering clinical practice and research of microorganism-skin interaction.

Fetal Skin Wound Healing: Key Extracellular Matrix Components and Regulators in Scarless Healing

Fetal skin at early gestational stage is able to regenerate and heal rapidly after wounding. The exact mechanisms and molecular pathways involved in this process are however still largely unknown. The numerous differences in the skin of the early fetus versus skin in later developmental stages might provide clues for the mechanisms of scarless healing. This review summarizes the differences between mammalian fetal skin and the skin at later developmental phases in healthy and wounded conditions, focusing on extracellular matrix components, which are crucial factors in the microenvironment that direct cells and tissue functions and hence the wound healing process.

Piezoelectric hydrogels for accelerating healing of diverse wound types

The skin, as the body's largest organ, plays a crucial role in protecting against mechanical forces and infections, maintaining fluid balance, and regulating body temperature. Therefore, skin wounds can significantly threaten human health and cause a heavy economic burden on society. Recently, bioelectric fields and electrical stimulation (ES) have been recognized as a promising pathway for modulating tissue engineering and regeneration of wounded skin. However, conventional hydrogel dressing lacks electrical generation capabilities and usually requires external stimuli to initiate the cell regeneration process, and the role of ES in different stages of healing is not fully understood. Therefore, to endow hydrogel-based wound dressings with piezoelectric properties, which can accelerate wound healing and potentially suppress infection via introducing ES, piezoelectric hydrogels (PHs) have emerged recently, combining the advantages of both piezoelectric nanomaterials and hydrogels beneficial for wound healing. Given the scarcity of systematic literature on the application of PHs in wound healing, this paper systematically discusses the principles of the piezoelectric effects, the design and fabrication of PHs, their piezoelectric properties, the way PHs trigger ES and the mechanisms by which they promote wound healing. Additionally, it summarizes the recent applications of PHs in various types of wounds, including traumatic wounds, pressure injuries, diabetic wounds, and infected wounds. Finally, the paper proposes future directions and challenges for the development of PH wound dressings for wound healing.

Deciphering mechanical cues in the microenvironment: from non-malignant settings to tumor progression

The tumor microenvironment functions as a dynamic and intricate ecosystem, comprising a diverse array of cellular and non-cellular components that precisely orchestrate pivotal tumor behaviors, including invasion, metastasis, and drug resistance. While unraveling the intricate interplay between the tumor microenvironment and tumor behaviors represents a tremendous challenge, recent research illuminates a crucial biological phenomenon known as cellular mechanotransduction. Within the microenvironment, mechanical cues like tensile stress, shear stress, and stiffness play a pivotal role by activating mechanosensitive effectors such as PIEZO proteins, integrins, and Yes-associated protein. This activation initiates cascades of intrinsic signaling pathways, effectively linking the physical properties of tissues to their physiological and pathophysiological processes like morphogenesis, regeneration, and immunity. This mechanistic insight offers a novel perspective on how the mechanical cues within the tumor microenvironment impact tumor behaviors. While the intricacies of the mechanical tumor microenvironment are yet to be fully elucidated, it exhibits distinct physical attributes from non-malignant tissues, including elevated solid stresses, interstitial hypertension, augmented matrix stiffness, and enhanced viscoelasticity. These traits exert notable influences on tumor progression and treatment responses, enriching our comprehension of the multifaceted nature of the microenvironment. Through this innovative review, we aim to provide a new lens to decipher the mechanical attributes within the tumor microenvironment from non-malignant contexts, broadening our knowledge on how these factors promote or inhibit tumor behaviors, and thus offering valuable insights to identify potential targets for anti-tumor strategies.

Receptor activity-modifying protein 1 regulates the differentiation of mouse skin fibroblasts by downregulating α-SMA expression via suppression of high mobility group AT-hook 1 to promote skin wound repair

Background

Skin innervation is very important for normal wound healing, and receptor activity-modifying protein 1 (RAMP1) has been reported to modulate calcitonin gene-related peptide (CGRP) receptor function and thus be a potential treatment target. This study aimed to elucidate the intricate regulatory effect of RAMP1 on skin fibroblast function, thereby addressing the existing knowledge gap in this area.

Methods

Immunohistochemical staining and immunofluorescence (IF) staining were used to measure the dynamic changes in the expression of RAMP1 and α-smooth muscle actin (α-SMA) in skin wound tissue in mice. Mouse skin fibroblasts (MSFs) stably transfected with Tet-on-Flag-RAMP1 overexpression (OE) and Tet-on-Flag control (Ctrl) lentiviruses were constructed for in vitro experiments. High mobility group AT-hook 1 (HMGA1) plasmids and α-SMA plasmids were used to overexpress HMGA1 and α-SMA, respectively. An α-SMA siRNA was used to silence α-SMA. Quantitative real-time polymerase chain reaction (qPCR), western blot and IF staining analyses were used to determine the mRNA and protein levels in the cells in different groups. A scratch wound healing assay was used to evaluate the cell migration ability of different groups. Cleavage under targets and release using nuclease (CUT & RUN) assays and dual-luciferase reporter assays were used to predict and verify the interaction between HMGA1 and the α-SMA promoter.

Results

RAMP1 and α-SMA protein expression levels in the dermis changed dynamically and were negatively correlated during dorsal skin wound healing in mice. RAMP1 OE in vitro inhibited the differentiation and promoted the migration of MSFs by decreasing α-SMA expression via the suppression of HMGA1, which was shown for the first time to bind to the α-SMA promoter and increase α-SMA transcription. RAMP1 OE also modulated extracellular matrix (ECM) synthesis and remodeling by promoting collagen III and MMP9 expression and decreasing collagen I, MMP2, and tissue inhibitor of metalloproteinases 1 expression.

Conclusions

Our findings suggest that RAMP1 OE decreases differentiation and promotes migration in MSFs by downregulating α-SMA expression via the suppression of HMGA1 and modulates ECM synthesis and remodeling, revealing a novel mechanism regulating α-SMA transcription, providing new insights into the RAMP1-mediated regulation of fibroblast function, and identifying effective nerve-related targets for skin wound repair.

Systemic factors associated with antler growth promote complete wound healing

Deer antlers are the only mammalian appendages that can fully regenerate from periosteum of pedicles (PP). This regeneration process starts from regenerative healing of wounds. Removal of PP abolishes antler regeneration, however, the regenerative cutaneous wound healing proceeds, indicating that some factors in the circulation contribute to this healing. In this study, we produced a wound in the scalp of deer either in antler regeneration period (ARP) (n = 3) or in non-ARP (n = 3). Results showed full regeneration took place only when the wound was created during ARP. Interestingly, topical application of systemic factors from ARP (n = 9) promoted regenerative wound healing in rats. Comparative proteomics analysis (n = 3) revealed that PRG4 and IGF-1 were high during ARP, and topical application of PRG4 + IGF-1 promoted restoration in rat FTE wounds. We believe that, ultimately, incorporating systemic factors into advanced wound care modalities could offer new opportunities for regenerative healing in the clinical setting.

Magnetic Nanoactuator-Protein Fiber Coated Hydrogel Dressing for Well-Balanced Skin Wound Healing and Tissue Regeneration

Despite significant progress in skin wound healing, it is still a challenge to construct multifunctional bioactive dressings based on a highly aligned protein fiber coated hydrogel matrix for antifibrosis skin wound regeneration that is indistinguishable to native skin. In this study, a "dual-wheel-driven" strategy is adopted to modify the surface of methacrylated gelatin (GelMA) hydrogel with highly aligned magnetic nanocomposites-protein fiber assemblies (MPF) consisting of photothermal responsive antibacteria superparamagnetic nanocomposites-fibrinogen (Fg) complexes as the building blocks. Whole-phase healing properties of the modified hydrogel dressing, GelMA-MPF (GMPF), stem from the integration of Fg protein with RGD peptide activity decorated on the surface of the antibacterial magnetic nanoactuator, facilitating facile and reproducible dressing preparation by self-assembly and involving biochemical, morphological, and biophysical cues. Payload and substantial release of copper ions for in situ catalytic production of nitric oxide (NO) from the fiber inorganic skeleton adsorbed by Fg molecules collectively regulate the proliferation, migration, reorganization, and transdifferentiation behavior of fibroblasts and fulfill antifibrosis in the process of skin wound healing and subcutaneous appendage regeneration. In full-thickness skin lesion mouse models, the complete regeneration of skin tissue with regenerated hair follicle cells and capillary blood vessels is realized in a temporally and spatially ordered manner.

Exploring the Revolutionary Impact of YAP Pathways on Physical and Rehabilitation Medicine

Cellular behavior is strongly influenced by mechanical signals in the surrounding microenvironment, along with external factors such as temperature fluctuations, changes in blood flow, and muscle activity, etc. These factors are key in shaping cellular states and can contribute to the development of various diseases. In the realm of rehabilitation physical therapies, therapeutic exercise and manual treatments, etc., are frequently employed, not just for pain relief but also to support recovery from diverse health conditions. However, the detailed molecular pathways through which these therapies interact with tissues and influence gene expression are not yet fully understood. The identification of YAP has been instrumental in closing this knowledge gap. YAP is known for its capacity to perceive and translate mechanical signals into specific transcriptional programs within cells. This insight has opened up new perspectives on how physical and rehabilitation medicine may exert its beneficial effects. The review investigates the involvement of the Hippo/YAP signaling pathway in various diseases and considers how different rehabilitation techniques leverage this pathway to aid in healing. Additionally, it examines the therapeutic potential of modulating the Hippo/YAP pathway within the context of rehabilitation, while also addressing the challenges and controversies that surround its use in physical and rehabilitation medicine.

Verteporfin combined with ROCK inhibitor promotes the restoration of corneal endothelial cell dysfunction in rats

Corneal endothelial cells (CECs) dysfunction frequently results in a hazy, edematous cornea due to corneal endothelial decompensation and is a major cause of corneal blindness. Drug interventions provide a less invasive alternative to corneal transplantation surgery. However, endothelial-to-mesenchymal transition (EndMT) limits CECs function. Rho-kinase (ROCK) inhibitors, shown in numerous studies to be an adjunctive therapy for CECs dysfunction, cannot completely reverse pathological EndMT caused by inflammatory environmental damage. Verteporfin (VP) is an inhibitor of Yes-associated protein (YAP) and has significant inhibitory effects on cell fibrosis and mesenchymal transition. Here, we explored VP's utility in mitigating EndMT during ROCK inhibitors treatment of corneal endothelial dysfunction. We surgically constructed a rat model of CECs injury and studied VP and ROCK inhibitors' effects on EndMT, cell proliferation, and corneal edema using RNA-Seq sequencing, immunofluorescence, optical coherence tomography, and qPCR. The results indicated that YAP expression in human fetal CECs was higher than in adults and decreased with age in rats. Moreover, YAP expression in human CECs was negatively correlated with functional genes, such as AQP1 and ATP1A1. VP effectively reversed EndMT and accelerated corneal hydration regression. However, it inhibited CECs proliferation. We also confirmed that the optimal ratio of VP combined with Y-27632 (ROCK inhibitor) was 1:1, promoting CECs proliferation and reversing EndMT by down-regulating transcription factors downstream of TGF-β signaling, thereby increasing CECs functional and intercellular adhesion proteins. These combined effects promote corneal endothelial damage repair, providing a new treatment strategy.

Multilayered hydrogel scaffold construct with native tissue matched elastic modulus: A regenerative microenvironment for urethral scar-free healing

The unsuitable deformation stimulus, harsh urine environment, and lack of a regenerative microenvironment (RME) prevent scaffold-based urethral repair and ultimately lead to irreversible urethral scarring. The researchers clarify the optimal elastic modulus of the urethral scaffolds for urethral repair and design a multilayered PVA hydrogel scaffold for urethral scar-free healing. The inner layer of the scaffold has self-healing properties, which ensures that the wound effectively resists harsh urine erosion, even when subjected to sutures. In addition, the scaffold's outer layer has an extracellular matrix-like structure that synergizes with adipose-derived stem cells to create a favorable RME. In vivo experiments confirm successful urethral scar-free healing using the PVA multilayered hydrogel scaffold. Further mechanistic study shows that the PVA multilayer hydrogel effectively resists the urine-induced inflammatory response and accelerates the transition of urethral wound healing to the proliferative phase by regulating macrophage polarization, thus providing favorable conditions for urethral scar-free healing. This study provides mechanical criteria for the fabrication of urethral tissue-engineered scaffolds, as well as important insights into their design.

Characteristics and Differences in the Antler Velvet Microbiota During Regeneration

The skin surface has a complex and dynamic ecosystem inhabited by a diverse microbiota. The wound formed by antler velvet shedding can naturally achieve regenerative restoration, but the changes in microbial composition that occur during antler velvet regeneration are largely unknown. In this study, we analyzed the antler velvet microbiota of sika deer at 15 days (Half) and 30 days (Full) post-pedicle casting using 16S rRNA gene sequencing. A total of 2659 OTUs were identified, which were assigned to 26 phyla, 304 families, and 684 genera. The core microbiota of the two groups were mainly composed of Atopostipes spp., Corynebacterium spp., Burkholderia spp., Staphylococcus spp., and Paracoccus spp. In comparison with the Full group, the Shannon, Simpson, Ace, and Chao 1 indices were significantly decreased in the Half group (p < 0.05). Principal coordinate analysis showed that there were significant differences in the microbial community between the Half and Full groups based on Bray-Curtis dissimilarity, weighted Unifrac distance, and unweighted Unifrac distance (p < 0.05). The relative abundances of bacteria belonging to the genera Staphylococcus, Romboutsia_B, and Dietzia increased significantly in the Half group, while the abundances of bacteria belonging to the genera Atopostipes, Psychrobacter, and Faecousia increased significantly in the Full group (p < 0.05). Correlation analysis showed that the relative abundances of bacteria belonging to the genera Staphylococcus, Romboutsia_B, and Dietzia positively correlated with arginine and proline metabolism (p < 0.05). These findings demonstrate that antler velvet regeneration is accompanied by distinct changes in microbial composition and highlight the potential roles of key taxonomy in wound healing and tissue regeneration.

Conserved roles of engrailed: patterning tissues and specifying cell types

More than 40 years ago, studies of the Drosophila engrailed and Hox genes led to major discoveries that shaped the history of developmental biology. We learned that these genes define the state of determination of cells that populate particular spatially defined regions: the identity of segmental domains by Hox genes, and the identity of posterior developmental compartments by engrailed. Hence, the boundaries that delimit spatial domains depend on engrailed. Here, we review the engrailed field, which now includes orthologs in Drosophila and mouse, as well as many other animals. We focus on fly and mouse and highlight additional functions that span early stages of embryogenesis and neural development.

Inactivity-mediated molecular adaptations: Insights from a preclinical model of physical activity reduction

Insufficient physical activity is associated with increased relative risk of cardiometabolic disease and is an independent risk factor for mortality. Experimentally reducing physical activity rapidly induces insulin resistance, impairs glucose handling, and drives metabolic inflexibility. These adaptations manifest during the early stages of physical inactivity, even when energy balance is maintained, suggesting that inactivity-mediated metabolic reprogramming is an early event that precedes changes in body composition. To identify mechanisms that promote metabolic adaptations associated with physical inactivity, we developed a mouse model of physical activity reduction that permits the study of inactivity in animals prior to the onset of overt changes in body composition. Adult mice were randomized into three groups: an inactive control group (standard rodent housing), an active control group (treadmill running 5 d/week for 6-weeks), and an activity reduction group (treadmill running for 4-weeks, followed by 2-weeks of inactivity). Transcriptional profiling of gastrocnemius muscle identified seven transcripts uniquely altered by physical activity reduction compared to the inactive and active control groups. Most identified transcripts had reported functions linked to bioenergetic adaptation. Future studies will provide deeper characterization of the function(s) of each the identified transcripts while also determining how inactivity affects transcriptional regulation in other tissues.

Dynamic duo: Cell-extracellular matrix interactions in hair follicle development and regeneration

Ectodermal organs, such as hair follicles, originate from simple epithelial and mesenchymal sheets through a complex developmental process driven by interactions between these cell types. This process involves dermal condensation, placode formation, bud morphogenesis, and organogenesis, and all of these processes require intricate interactions among various tissues. Recent research has emphasized the crucial role of reciprocal and dynamic interactions between cells and the extracellular matrix (ECM), referred to as the "dynamic duo", in the development of ectodermal organs. These interactions provide spatially and temporally changing biophysical and biochemical cues within tissues. Using the hair follicle as an example, this review highlights two types of cell-ECM adhesion units-focal adhesion-type and hemidesmosome-type adhesion units-that facilitate communication between epithelial and mesenchymal cells. This review further explores how these adhesion units, along with other cell-ECM interactions, evolve during hair follicle development and regeneration, underscoring their importance in guiding both developmental and regenerative processes.