Hypoxia macrophage-derived exosomal miR-26b-5p targeting PTEN promotes the development of keloids

Inhibition of CDK5 signaling mediated inflammation in macrophages promotes cutaneous wound healing

Cyclin-dependent kinase 5 (CDK5) plays a critical role in the inflammatory response. Macrophages are pivotal orchestrators of inflammation, fibrosis, and wound repair. However, the effectiveness of CDK5 in macrophages on cutaneous wound healing remains inadequately characterized. We determined the role of CDK5 signaling pathway in macrophages in mouse cutaneous wound healing through the established macrophage-specific deletion of CDK5 (myeCDK5-/-) mice and the pharmacological CDK5 inhibitor Roscovitine. Phosphorylated proteomics, western blotting, Masson staining, and dualimmunofluorescence staining were performed to investigate the potential mechanisms underlying CDK5-mediated inflammatory regulation in macrophages in wound healing. CDK5 expression and phosphorylation were both elevated significantly in cutaneous wound healing process in mice. Moreover, an accelerated wound healing in myeCDK5-/- mice was exhibited with the reduced pro-inflammatory mediators (IL-1β and iNOS) and the elevated anti-inflammatory markers (IL-10 and CD163) expression significantly. CDK5 deficiency in macrophages enhanced tissue remodeling, evidenced by increased collagen deposition and capillary density (CD31+ cells). Consistently, Roscovitine-treated mice also showed accelerated wound healing, accompanied by decreased pro-inflammatory factors and increased anti-inflammatory markers at the wound site. Mechanistically, the decreased phosphorylation of SIRT1 at the Ser14 and Ser47 sites, as a substrate of CDK5, was confirmed in myeCDK5-/- mice. These data are the first to indicate that CDK5 signaling-dependent regulation of SIRT1 phosphorylation in macrophage-mediated inflammation is required for the wound healing process, warranting consideration of the CDK5-SIRT1 pathway as a therapeutic target for cutaneous wound healing.

Single-cell RNA sequencing highlights the role of proinflammatory fibroblasts, vascular endothelial cells, and immune cells in the keloid immune microenvironment

BACKGROUND

Keloids, characterized by an aberrant wound-healing process and a highly complex immune microenvironment, pose significant challenges for clinical management. Fibroblasts and vascular endothelial cells (VEC) were identified as the leading cells of keloid development. However, their roles in the keloid immune landscape have yet to be thoroughly elucidated.

METHODS

To explore the functional state of cells in the immune landscape of keloids, we conducted a single-cell RNA sequencing analysis on the tissue from three keloid lesions and two specimens of healthy skin. We simultaneously utilized available keloid data from the public database for external validation.

RESULTS

Specific subsets, such as proinflammatory fibroblasts (piF) and VEC, were markedly elevated in lesional skin compared to normal skin. Subsequent differential gene expression and Gene Ontology analyses indicated that these subsets may be involved in shaping the microenvironment. In keloids, there is an increased expression of immune-associated genes (P < 0.05), including TNFRSF6B, HGF, and TGFB3, alongside a decreased expression of inflammatory chemokines in the piF. Moreover, the significant upregulation of immune suppressive genes (P < 0.05), including CD39, CD73, and HIF1A, suggested the potential involvement of VEC as a conditional immune subpopulation in the keloid microenvironment. Immune cell communication analysis revealed preferential enrichment of macrophages and Tregs, highlighting intensified macrophage-centered interactions within the keloid microenvironment.

CONCLUSION

Our study highlighted the role of piF and VEC in the immune microenvironment of keloids for the first time, providing potential targets for therapeutic development.

Twist-related protein 1 promotes transforming growth factor β receptor 1 in keloid fibroblasts via regulating the stability of myocyte enhancer factor 2A

Background

Keloid scarring is caused by a fibroproliferative disorder due to abnormal activation of genes, the underlying mechanism of which is still unclear. The basic helix-loop-helix transcription factor Twist-related protein 1 (TWIST1) controls cell proliferation and differentiation in tissue development and disease processes. In this study, we aimed to clarify the essential role of TWIST1 in the pathogenesis of keloids.

Methods

Immunohistochemistry, cell counting kit-8 assays, western blotting, PCR, matrigel invasion assays and immunofluorescence assays were applied to demonstrate the effects and mechanisms of TWIST1 in fibroblasts derived from normal skin and keloids. Mass spectrometry, ubiquitination assays, chromatin immunoprecipitation and dual luciferase reporter assay were applied to explore the interaction of TWIST1 with downstream molecules.

Results

In the present study, we confirmed that TWIST1 was upregulated in keloid tissue of patients and in keloid-derived fibroblasts (KFBs). In vitro, TWIST1 inhibition prevented KFB proliferation, invasion and activation. We also discovered a link between TWIST1 and the transforming growth factor β (TGF-β) signaling related molecules TGF-β receptor 1 (TΒR1), SMAD family member 2 (Smad2) and Smad3, and the fibrosis markers α-smooth muscle actin, collagen type I and collagen type III in KFBs. Mechanistically, we uncovered a brand-new mechanism by which TWIST1 interacts with myocyte enhancer factor 2A (MEF2A) and suppresses its ubiquitination and degradation. Using chromatin immunoprecipitation and dual-luciferase reporter assay, TΒR1 was identified as a novel downstream target of MEF2A, which directly binds to its promoter. Overexpression of TWIST1 promoted the recruitment of MEF2A to the TΒR1 promoter and restored TΒR1 functional expression.

Conclusions

Our research highlights a significant function of TWIST1 in the development of keloid and its related fibroblasts, partially facilitated by elevated MEF2A-dependent TΒR1 expression. Blocking the expression of TWIST1 in KFBs could potentially pave a novel therapeutic avenue for keloid treatment.

Comprehensive Bioinformatics Analysis Reveals the Potential Role of the hsa_circ_0001081/miR-26b-5p Axis in Regulating COL15A1 and TRIB3 within Hypoxia-Induced miRNA/mRNA Networks in Glioblastoma Cells

Background/Objectives: The intrinsic molecular heterogeneity of glioblastoma (GBM) is one of the main reasons for its resistance to conventional treatment. Mesenchymal GBM niches are associated with hypoxic signatures and a negative influence on patients' prognosis. To date, competing endogenous RNA (ceRNA) networks have been shown to have a broad impact on the progression of various cancers. In this study, we decided to construct hypoxia-specific microRNA/ messengerRNA (miRNA/mRNA) networks with a putative circular RNA (circRNA) regulatory component using available bioinformatics tools. Methods: For ceRNA network construction, we combined publicly available data deposited in the Gene Expression Omnibus (GEO) and interaction pairs obtained from miRTarBase and circBank; a differential expression analysis of GBM cells was performed with limma and deseq2. For the gene ontology (GO) enrichment analysis, we utilized clusterProfiler; GBM molecular subtype analysis was performed in the Glioma Bio Discovery Portal (Glioma-BioDP). Results: We observed that miR-26b-5p, generally considered a tumor suppressor, was upregulated under hypoxic conditions in U-87 MG cells. Moreover, miR-26b-5p could potentially inhibit TRIB3, a gene associated with tumor proliferation. Protein-protein interaction (PPI) network and GO enrichment analyses identified a hypoxia-specific subcluster enriched in collagen-associated terms, with six genes highly expressed in the mesenchymal glioma group. This subcluster included hsa_circ_0001081/miR-26b-5p-affected COL15A1, a gene downregulated in hypoxic U-87 MG cells yet highly expressed in the mesenchymal GBM subtype. Conclusions: The interplay between miR-26b-5p, COL15A1, and TRIB3 suggests a complex regulatory mechanism that may influence the extracellular matrix composition and the mesenchymal transformation in GBM. However, the precise impact of the hsa_circ_0001081/miR-26b-5p axis on collagen-associated processes in hypoxia-induced GBM cells remains unclear and warrants further investigation.

New challenges in scar therapy: the novel scar therapy strategies based on nanotechnology

The pathological mechanism of pathological scar is highly complex, encompassing the abnormalities of diverse cytokines, signaling pathways and regulatory factors. To discover more preferable scar treatment options, a variety of distinct approaches have been utilized clinically. Nevertheless, these treatments possess certain side effects and are inclined to relapse. Presently, pathological scar treatment remains a clinical conundrum, and there is an urgent demand for treatment methods that are safe, less traumatic and have lower recurrence rates. New drug delivery systems, novel therapeutic drugs and therapy strategies can enable drugs to permeate the skin effectively, decrease side effects, enhance drug efficacy and even achieve pain-free self-administration. Currently, novel nanotechnologies such as nanomicroneedles, photodynamics mediated by novel photosensitizers, bioelectrical stimulation and 3D printed dressings have been developed for the effective treatment of pathological scars. Additionally, innovative nanoscale fillers, including nano-fat and engineered exosomes, can serve as novel therapeutic agents for the efficient treatment of pathological scars. The intervention of nanomaterials can enhance drug absorption, stabilize and safeguard the active ingredients of drugs, delay or control drug release and enhance bioavailability. This article reviews these new treatment strategies for scar to explore novel approaches for efficient and safe for keloid treatment.

Macrophage plasticity: signaling pathways, tissue repair, and regeneration

Macrophages are versatile immune cells with remarkable plasticity, enabling them to adapt to diverse tissue microenvironments and perform various functions. Traditionally categorized into classically activated (M1) and alternatively activated (M2) phenotypes, recent advances have revealed a spectrum of macrophage activation states that extend beyond this dichotomy. The complex interplay of signaling pathways, transcriptional regulators, and epigenetic modifications orchestrates macrophage polarization, allowing them to respond to various stimuli dynamically. Here, we provide a comprehensive overview of the signaling cascades governing macrophage plasticity, focusing on the roles of Toll-like receptors, signal transducer and activator of transcription proteins, nuclear receptors, and microRNAs. We also discuss the emerging concepts of macrophage metabolic reprogramming and trained immunity, contributing to their functional adaptability. Macrophage plasticity plays a pivotal role in tissue repair and regeneration, with macrophages coordinating inflammation, angiogenesis, and matrix remodeling to restore tissue homeostasis. By harnessing the potential of macrophage plasticity, novel therapeutic strategies targeting macrophage polarization could be developed for various diseases, including chronic wounds, fibrotic disorders, and inflammatory conditions. Ultimately, a deeper understanding of the molecular mechanisms underpinning macrophage plasticity will pave the way for innovative regenerative medicine and tissue engineering approaches.