Scar formation is characterized by dynamic alterations in collagen secretion, which critically determine scar morphology and pathological progression. In fibroblasts, collagen secretion is initiated through the activation of cytokine- and integrin-mediated signaling pathways, which promote collagen gene transcription. The procollagen polypeptide α chains undergo extensive post-translational modifications, including hydroxylation and glycosylation, within the endoplasmic reticulum (ER), followed by folding and assembly into triple-helical procollagen. Subsequent intracellular trafficking involves the sequential transport of procollagen through the ER, Golgi apparatus, and plasma membrane, accompanied by further structural refinements prior to extracellular secretion. Once secreted, procollagen is enzymatically processed to form mature collagen fibrils, which drive scar tissue remodeling. Recent advances in elucidating regulation of collagen secretion have identified pivotal molecular targets, such as transforming growth factor-beta 1 (TGF-β1), prolyl 4-hydroxylase (P4H), heat shock protein 47 (HSP47), and transport and Golgi organization protein 1 (TANGO1), providing novel therapeutic strategies to mitigate pathological scar hyperplasia and improve regenerative outcomes. This review provides a comprehensive analysis of the molecular mechanisms governing collagen secretion during scar formation, with emphasis on signaling cascades, procollagen biosynthesis, intracellular transport dynamics, and post-translational modifications, thereby offering a framework for developing targeted anti-scar therapies.
Humans ; Collagen/metabolism* ; Cicatrix/pathology* ; Signal Transduction ; Transforming Growth Factor beta1/metabolism* ; Fibroblasts/metabolism* ; Animals

Frostbite is the most common cold injury and is caused by both immediate cold-induced cell death and the gradual development of localized inflammation and tissue ischemia. Delayed healing of frostbite often leads to scar formation, which not only causes psychological distress but also tends to result in the development of secondary malignant tumors. Therefore, a rapid healing method for frostbite wounds is urgently needed. Herein, we used a mouse skin model of frostbite injury to evaluate the recovery process after frostbite. Moreover, single-cell transcriptomics was used to determine the patterns of changes in monocytes, macrophages, epidermal cells, and fibroblasts during frostbite. Most importantly, human-induced pluripotent stem cell (hiPSC)-derived skin organoids combined with gelatin-hydrogel were constructed for the treatment of frostbite. The results showed that skin organoid treatment significantly accelerated wound healing by reducing early inflammation after frostbite and increasing the proportions of epidermal stem cells. Moreover, in the later stage of wound healing, skin organoids reduced the overall proportions of fibroblasts, significantly reduced fibroblast-to-myofibroblast transition by regulating the integrin α5β1-FAK pathway, and remodeled the extracellular matrix (ECM) through degradation and reassembly mechanisms, facilitating the restoration of physiological ECM and reducing the abundance of ECM associated with abnormal scar formation. These results highlight the potential application of organoids for promoting the reversal of frostbite-related injury and the recovery of skin functions. This study provides a new therapeutic alternative for patients suffering from disfigurement and skin dysfunction caused by frostbite.
Animals ; Organoids/metabolism* ; Mice ; Humans ; Wound Healing ; Frostbite/metabolism* ; Skin/pathology* ; Induced Pluripotent Stem Cells/cytology* ; Cicatrix/pathology* ; Fibroblasts/metabolism* ; Disease Models, Animal ; Mice, Inbred C57BL ; Extracellular Matrix/metabolism* ; Male

OBJECTIVES: To propose a hypothesis that aloe-emodin may inhibit scar tissue fibrosis through thrombospondin-1(THBS1)-PI3K-Akt pathway. METHODS: By cultivating fibroblasts derived from scar tissue after cleft palate surgery in humans, aloe emodin of different concentrations (10, 20, 30, 40 and 50 μmol/L) was added to the cells which activity was detected. At the same time, transcriptome sequencing was performed on scar tissue and cells, and bioinformatics methods were used to explore potential targets and signaling pathways of scar tissue fibrosis. RESULTS: Aloe-emodin had a concentration dependent inhibitory effect on fibroblast proliferation,with the 40 μmol/L concentration group showing the most significant effect. The results of tissue and cell sequencing indicated that differentially expressed genes were significantly enriched in extracellular matrix-receptor interaction pathway, and shared a common differential gene which was THBS1. The ORA analysis results indicated that differentially expressed genes, including THBS1, were significantly enriched in the PI3K-Akt signaling pathway. CONCLUSIONS Aloe emodin may inhibit the PI3K-Akt pathway by downregulating THBS1, thereby reducing the proliferation activity of fibroblasts derived from postoperative palatal scar tissue.
Thrombospondin 1/genetics* ; Humans ; Signal Transduction/drug effects* ; Fibroblasts/cytology* ; Proto-Oncogene Proteins c-akt/metabolism* ; Fibrosis ; Phosphatidylinositol 3-Kinases/metabolism* ; Cicatrix/metabolism* ; Cell Proliferation/drug effects* ; Anthraquinones/pharmacology* ; Cells, Cultured

Our previous study has shown that p66^Shc plays an important role in the process of myocardial regeneration in newborn mice, and p66^Shc deficiency leads to weakened myocardial regeneration in newborn mice. This study aims to explore the role of p66^Shc protein in myocardial injury repair after myocardial infarction in adult mice, in order to provide a new target for the treatment of myocardial injury after myocardial infarction. Mouse myocardial infarction models of adult wild-type (WT) and p66^Shc knockout (KO) were constructed by anterior descending branch ligation. The survival rate and heart-to-body weight ratio of two models were compared and analyzed. Masson's staining was used to identify scar area of injured myocardial tissue, and myocyte area was determined by wheat germ agglutinin (WGA) staining. TUNEL staining was used to detect the cardiomyocyte apoptosis. The protein expression of brain natriuretic peptide (BNP), a common marker of myocardial hypertrophy, was detected by Western blotting. The results showed that there was no significant difference in survival rate, myocardial scar area, myocyte apoptosis, and heart weight to body weight ratio between the WT and p66^ShcKO mice after myocardial infarction surgery. Whereas the protein expression level of BNP in the p66^ShcKO mice was significantly down-regulated compared with that in the WT mice. These results suggest that, unlike in neonatal mice, the deletion of p66^Shc has no significant effect on myocardial injury repair after myocardial infarction in adult mice.
Animals ; Mice ; Body Weight ; Cicatrix/metabolism* ; Mice, Knockout ; Myocardial Infarction/genetics* ; Oxidative Stress ; Shc Signaling Adaptor Proteins/metabolism* ; Src Homology 2 Domain-Containing, Transforming Protein 1/metabolism*

Nerve regeneration in adult mammalian spinal cord is poor because of the lack of intrinsic regeneration of neurons and extrinsic factors - the glial scar is triggered by injury and inhibits or promotes regeneration. Recent technological advances in spatial transcriptomics (ST) provide a unique opportunity to decipher most genes systematically throughout scar formation, which remains poorly understood. Here, we first constructed the tissue-wide gene expression patterns of mouse spinal cords over the course of scar formation using ST after spinal cord injury from 32 samples. Locally, we profiled gene expression gradients from the leading edge to the core of the scar areas to further understand the scar microenvironment, such as neurotransmitter disorders, activation of the pro-inflammatory response, neurotoxic saturated lipids, angiogenesis, obstructed axon extension, and extracellular structure re-organization. In addition, we described 21 cell transcriptional states during scar formation and delineated the origins, functional diversity, and possible trajectories of subpopulations of fibroblasts, glia, and immune cells. Specifically, we found some regulators in special cell types, such as Thbs1 and Col1a2 in macrophages, CD36 and Postn in fibroblasts, Plxnb2 and Nxpe3 in microglia, Clu in astrocytes, and CD74 in oligodendrocytes. Furthermore, salvianolic acid B, a blood-brain barrier permeation and CD36 inhibitor, was administered after surgery and found to remedy fibrosis. Subsequently, we described the extent of the scar boundary and profiled the bidirectional ligand-receptor interactions at the neighboring cluster boundary, contributing to maintain scar architecture during gliosis and fibrosis, and found that GPR37L1_PSAP, and GPR37_PSAP were the most significant gene-pairs among microglia, fibroblasts, and astrocytes. Last, we quantified the fraction of scar-resident cells and proposed four possible phases of scar formation: macrophage infiltration, proliferation and differentiation of scar-resident cells, scar emergence, and scar stationary. Together, these profiles delineated the spatial heterogeneity of the scar, confirmed the previous concepts about scar architecture, provided some new clues for scar formation, and served as a valuable resource for the treatment of central nervous system injury.
Mice ; Animals ; Gliosis/pathology* ; Cicatrix/pathology* ; Spinal Cord Injuries ; Astrocytes/metabolism* ; Spinal Cord/pathology* ; Fibrosis ; Mammals ; Receptors, G-Protein-Coupled

Scarring, naturally induced by fibroblasts(Fb) during wound healing, is an essential process in response to repair damaged tissue. Excessive Fb proliferation which produces the excessive collagen deposition, including increased extracellular matrix synthesis or insufficient decomposition, typically contributes to hypertrophic scar(HS) formation. Although exact mechanisms of HS are not yet fully understood, it is generally believed that dysfunction of Fb and regulation of signal pathways play an important role in HS formation. Biologically, Fb function is affected by various factors such as cytokines, extracellular matrix and itself. In addition, modifications of miRNA, ceRNA, lncRNA, peptides and histones participate in HS formation by affecting the biological function of Fb. Despite the clinical importance, very few therapeutic modalities are available to prevent HS. To achieve this, a deeper characterization of Fb is required to identify mechanisms of HS. To the aspect of HS prevention and treatment, we review recent findings, concentrating on Fb function and collagen secretion. The objective of this article is to frame the current understanding, gain the deeper insights into Fb function, and provide the more comprehensive cognition and perspective for prevention and treatment of HS.
Humans ; Cicatrix, Hypertrophic/metabolism* ; Collagen/therapeutic use* ; Fibroblasts ; Signal Transduction ; Extracellular Matrix/metabolism*

OBJECTIVES: Steroidal anti-inflammatory drugs have certain side effects in the treatment of hypertrophic scar, and the scar recurrence is easy after withdrawal of steroid anti-inflammatory drugs. Finding reliable alternative drugs is an effective means to improve this defect. Aspirin, a traditional non-steroidal anti-inflammatory drug, is safe for topical use and has anti-inflammatory effects similar to those of steroidal anti-inflammatory drugs, which may have similar effects on the treatment of hypertrophic scar. This study aims to investigate the inhibitory effect of aspirin on the proliferation of hypertrophic scar in rabbit ears and the underlying mechanism. METHODS: The rabbit ear hypertrophic scar models were prepared. The rabbits were randomly divided into a normal skin group (group A), a blank control group (group B), a 0.9% NaCl group (group C), a 0.2% aspirin group (group D), a 0.5% aspirin group (group E), a 2% aspirin group (group F), and a triamcinolone acetonide group (group G). Macroscopic observation of hyperplasia was performed 8 weeks after local injection of the scar, followed by collecting the scar tissue samples for HE staining, Masson staining, and immunohistochemistry, respectively to assess the proliferation of fibroblasts and collagen fibers, and calculate the hypertrophic index, microvessel density, and immunohistochemical score. RESULTS: All rabbit ear hypertrophic scar models were successfully constructed. In groups B and C, the hypertrophic scar edge was irregular, with reddish protruding epidermis, significant contracture and hard touch. In group D, E, and F, with the increase of aspirin administration concentration, the scar became thinner and gradually flat, the proliferation of fibrocytes and collagen fibers was weakened, and the hypertrophic index was gradually decreased (P<0.05). Immunohistochemistry showed that the expression of β-catenin was decreased in the group D, E and F in turn, and the immunohistochemical score was gradually decreased (P<0.05). There was no significant difference in hypertrophic index, microvessel density, and immunohistochemical score (all P>0.05). CONCLUSIONS Local injection of aspirin can reduce the generation of hypertrophic scar in a dose-dependent manner within a certain concentration range; aspirin inhibits the growth of hypertrophic scar in rabbit ears by inhibiting Wnt/β-catenin signal pathway; 2% aspirin and 40 mg/mL triamcinolone acetonide have similar curative efficacy on hypertrophic scar.
Animals ; Anti-Inflammatory Agents/therapeutic use* ; Aspirin/therapeutic use* ; Cicatrix, Hypertrophic/pathology* ; Collagen ; Rabbits ; Signal Transduction ; Triamcinolone Acetonide/therapeutic use* ; beta Catenin/metabolism*

Hypertrophic scar is a pathological repair result of excessive accumulation of extracellular matrix after skin damage, which affects the appearance and function of patients with varying degrees. The degree of scar formation is directly related to the strength of inflammatory reaction during wound healing, and excessive or prolonged inflammatory response increases the incidence of hypertrophic scars. Interleukin-6 (IL-6) is a pleiotropic cytokine that is involved in regulating the fibrotic network composed of fibroblasts, macrophages, keratinocytes, and vascular endothelial cells, and is closely related to the formation of hypertrophic scars. This article reviews the role of IL-6 and its signaling pathway in hypertrophic scar formation.
Cicatrix, Hypertrophic/pathology* ; Endothelial Cells/metabolism* ; Fibroblasts/metabolism* ; Humans ; Interleukin-6 ; Skin/pathology* ; Wound Healing/physiology*

Objective: To investigate the regulatory effects and signaling mechanism of sodium ferulate on the proliferation and apoptosis of human skin hypertrophic scar fibroblasts (HSFbs). Methods: The experimental research methods were used. The 4^th-6^th passage of HSFbs from human skin were used for the following experiments. HSFbs were co-cultured with sodium ferulate at final mass concentrations of 1, 1×10^-1, 1×10^-2, 1×10^-3, 1×10^-4, 1×10^-5, and 1×10^-6 mg/mL for 48 hours, and methyl thiazolyl tetrazolium method was used to determine the cell absorbance values and linear regression was used to analyze the half lethal concentration (LC50) of sodium ferulate (n=6). HSFbs were co-cultured with sodium ferulate at final mass concentrations of 0.1, 0.2, 0.3, and 0.4 mg/mL for 24, 48, 72, and 96 hours, and methyl thiazolyl tetrazolium method was used to determine the cell absorbance values and the cell proliferation inhibition rate was calculated (n=3). According to the random number table, the cells were divided into 0.300 mg/mL sodium ferulate group, 0.030 mg/mL sodium ferulate group, 0.003 mg/mL sodium ferulate group treated with sodium ferulate at corresponding final mass concentrations, and negative control group without any treatment. After 72 hours of culture, the cell absorbance values were determined by methyl thiazolyl tetrazolium method (n=5), the microscopic morphology of cells was observed by transmission electron microscope (n=3), the cell apoptosis was detected by TdT-mediated dUTP-biotin nick end labeling (TUNEL) assay and the apoptosis index was calculated (n=4), the protein expressions of B lymphocystoma-2 (Bcl-2), Bcl-2-associated X protein (Bax), and cysteine aspartic acid specific protease-3 (caspase-3) were determined by immunohistochemistry (n=4), and the protein expressions of transformed growth factor β₁ (TGF-β₁), phosphorylated Smad2/3, phosphorylated Smad4, and phosphorylated Smad7 were detected by Western blotting (n=4). Data were statistically analyzed with one-way analysis of variance and Dunnett test. Results: The LC50 of sodium ferulate was 0.307 5 mg/mL. After being cultured for 24-96 hours, the cell proliferation inhibition rates of cells treated with sodium ferulate at four different mass concentrations tended to increase at first but decrease later, which reached the highest after 72 hours of culture, so 72 hours was chosen as the processing time for the subsequent experiments. After 72 hours of culture, the cell absorbance values in 0.003 mg/mL sodium ferulate group, 0.030 mg/mL sodium ferulate group, and 0.300 mg/mL sodium ferulate group were 0.57±0.06, 0.53±0.04, 0.45±0.05, respectively, which were significantly lower than 0.69±0.06 in negative control group (P<0.01). After 72 hours of culture, compared with those in negative control group, the cells in the three groups treated with sodium ferulate showed varying degrees of nuclear pyknosis, fracture, or lysis, and chromatin loss. In the cytoplasm, mitochondria were swollen, the rough endoplasmic reticulum was expanded, and local vacuolation gradually appeared. After 72 hours of culture, compared with that in negative control group, the apoptosis indexes of cells were increased significantly in 0.003 mg/mL sodium ferulate group, 0.030 mg/mL sodium ferulate group, and 0.300 mg/mL sodium ferulate group (P<0.05 or P<0.01). After 72 hours of culture, compared with those in negative control group, the protein expressions of Bcl-2 of cells in 0.300 mg/mL sodium ferulate group was significantly decreased (P<0.01), the protein expressions of Bax of cells in 0.030 mg/mL sodium ferulate group and 0.300 mg/mL sodium ferulate group were significantly increased (P<0.05), and the protein expression of caspase-3 of cells in 0.300 mg/mL sodium ferulate group was significantly increased (P<0.01). After 72 hours of culture, compared with those in negative control group, the protein expression levels of TGF-β₁, phosphorylated Smad2/3, and phosphorylated Smad4 of cells in 0.030 mg/mL sodium ferulate group and 0.300 mg/mL sodium ferulate group were significantly decreased (P<0.05 or P<0.01), and the protein expression levels of phosphorylated Smad7 of cells in 0.003 mg/mL sodium ferulate group, 0.030 mg/mL sodium ferulate group, and 0.300 mg/mL sodium ferulate group were significantly increased (P<0.01). Conclusions: Sodium ferulate can inhibit the proliferation of HSFbs of human skin and promote the apoptosis of HSFbs of human skin by blocking the expression of key proteins on the TGF-β/Smad signaling pathway and synergistically activating the mitochon- drial apoptosis pathway.
Apoptosis ; Caspase 3/metabolism* ; Cell Proliferation ; Cicatrix, Hypertrophic/metabolism* ; Coumaric Acids ; Fibroblasts/metabolism* ; Humans ; Signal Transduction ; bcl-2-Associated X Protein/pharmacology*

OBJECTIVE: To study the anti- scarring effect of rapamycin in rabbits receiving glaucoma filtering surgery. METHODS: Ninety-six Chinchilla rabbits were randomized equally into 3 rapamycin treatment groups and one control group. All the rabbits underwent trabeculectomy, after which the rabbits in the 3 rapamycin groups were treated with eye drops containing 1%, 3%, or 5% rapamycin in the operated eyes, and those in the control groups were given castor oil 4 times a day. The intraocular pressure (IOP) and inflammatory reaction in the treated eyes were observed, and the PCNA-positive cells in the filtering bleb were detected using immunohistochemistry. RTFs isolated from the Tenon's capsule of the rabbits were cultured , and the expressions of caspase-3, caspase-8, and caspase-9 in the fibroblasts were detected after treatment with different concentrations of rapamycin. RESULTS: The IOP was significantly lower in rapamycin-treated group than in the control group after the surgery ( < 0.05). The counts of the PCNA-positive cells were significantly lower in rapamycin-treated rabbits than in the control group ( < 0.05). Rapamycin treatment dose-dependently increased the expressions of caspase-3 and caspase- 9 at both the mRNA ( < 0.001) and protein ( < 0.001) levels without causing significant changes in the expressions of caspase-8. CONCLUSIONS Rapamycin can inhibit excessive proliferation of the fibroblasts in the filtering bleb to reduce scar formation after glaucoma filtration surgery in rabbits. Rapamycin also increases the expressions of caspase-3 and caspase-9 to induce apoptosis of the RTFs.
Animals ; Caspase 3 ; metabolism ; Caspase 9 ; metabolism ; Cell Proliferation ; drug effects ; Cicatrix ; prevention & control ; Filtering Surgery ; adverse effects ; Glaucoma ; surgery ; Intraocular Pressure ; Postoperative Complications ; enzymology ; prevention & control ; Proliferating Cell Nuclear Antigen ; analysis ; Rabbits ; Random Allocation ; Sirolimus ; therapeutic use ; Trabeculectomy