Exosomal miR-155 from M1-polarized macrophages promotes EndoMT and impairs mitochondrial function via activating NF-κB signaling pathway in vascular endothelial cells after traumatic spinal cord injury

The Immune Microenvironment: New Therapeutic Implications in Organ Fibrosis

Fibrosis, characterized by abnormal deposition of structural proteins, is a major cause of tissue dysfunction in chronic diseases. The disease burden associated with progressive fibrosis is substantial, and currently approved drugs are unable to effectively reverse it. Immune cells are increasingly recognized as crucial regulators in the pathological process of fibrosis by releasing effector molecules, such as cytokines, chemokines, extracellular vesicles, metabolites, proteases, or intercellular contact. Therefore, targeting the immune microenvironment can be a potential strategy for fibrosis reduction and reversion. This review summarizes the recent advances in the understanding of the immune microenvironment in fibrosis including phenotypic and functional transformations of immune cells and the interaction of immune cells with other cells. The novel opportunities for the discovery and development of drugs for immune microenvironment remodeling and their associated challenges are also discussed.

Exosomal non-coding RNAs: gatekeepers of inflammation in autoimmune disease

Autoimmune diseases (AIDs) are marked by systemic inflammation and immune dysregulation, yet current therapies often fail to target their underlying causes. Emerging evidence positions exosomal non-coding RNAs (ncRNAs)-including miRNAs, lncRNAs, and circRNAs-as key regulators of inflammatory pathways, providing critical insights into AID pathogenesis. This review synthesizes recent advances in how these ncRNAs orchestrate immune cell communication, modulate inflammatory mediators, and drive microglial activation in neuroinflammatory AIDs. It evaluates their dual role as disease amplifiers (e.g., miR-155 in lupus, miR-326 in rheumatoid arthritis) and therapeutic targets, emphasizing their potential to reprogram immune responses or deliver anti-inflammatory agents. In this review, we first provide a glimpse into the pathogenesis of autoimmune diseases and delve into the structure and function of exosomes, emphasizing their role in cell-cell communication. We then discuss the regulatory roles of exosomal ncRNAs in immune modulation, detailing their types, functions, and mechanisms of action. Finally, we examine the implications of exosomes and exosomal ncRNAs in the context of autoimmune diseases, with a particular focus on microglial activation and its contribution to neuroinflammation.

Biological engineering approaches for modulating the pathological microenvironment and promoting axonal regeneration after spinal cord injury

Functional recovery following spinal cord injury (SCI) presents significant challenges and imposes a substantial burden on society. Current research primarily focuses on minimizing damage and promoting regeneration to enhance functional recovery after SCI. Following SCI, secondary injuries such as mitochondrial dysfunction, vascular rupture, inflammatory responses, and glial scarring occur in the lesion area, forming the pathological microenvironment. These factors expand the extent of damage, exacerbate injury severity, and severely impede axonal regeneration after SCI. Modulating the pathological microenvironment through various interventions may facilitate axonal regeneration and promote functional recovery after SCI. This article reviews the influence and research advancements in axon regeneration concerning mitochondrial dysfunction, inflammatory response, and glial scar formation after SCI. Additionally, it integrates insights from bioengineering to improve the pathological microenvironment, summarizing the progress in axon regeneration research. The review concludes with novel strategies for enhancing axon regeneration, offering fresh perspectives for future investigations.

Extracellular vesicle-packaged GBP2 from macrophages aggravates sepsis-induced acute lung injury by promoting ferroptosis in pulmonary vascular endothelial cells

Macrophages play a critical role in the development of sepsis-induced acute lung injury (si-ALI), with extracellular vesicles (EVs) acting as crucial mediators. However, the effects and mechanisms of macrophage-derived EVs on si-ALI remain unclear. This study demonstrated that macrophage-derived EVs induce endothelial ferroptosis and barrier disruption during sepsis. Through proteomic sequencing and reanalysis of transcriptomic and single-cell sequencing data, guanylate-binding protein 2 (GBP2) was identified as a key EV molecule. Elevated GBP2 expression was observed in EVs and monocytes from the peripheral blood of sepsis patients, in LPS-stimulated THP-1 and RAW264.7 cells and their secreted EVs, and in macrophages within the lungs of CLP mice. Additionally, GBP2 expression in EVs showed a positive correlation with vascular barrier injury biomarkers, including ANGPT2, Syndecan-1, and sTM. Modulating GBP2 levels in macrophage-derived EVs affected EV-induced ferroptosis in endothelial cells. The mechanism by which GBP2 binds directly to OTUD5 and promotes GPX4 ubiquitination was elucidated using RNA interference, adeno-associated virus transfection, and endothelial-specific Gpx4 knockout mice. A high-throughput screening of small-molecule compounds targeting GBP2 was conducted. Molecular docking, molecular dynamics simulations, and cellular thermal shift assays further confirmed that Plantainoside D (PD) has a potent binding affinity for GBP2. PD treatment inhibited the interaction between GBP2 and OTUD5, leading to a reduction in GPX4 ubiquitination. Further research revealed that PD treatment enhanced the pulmonary protective effects of GBP2 inhibition. In conclusion, this study explored the role of EV-mediated signaling between macrophages and pulmonary vascular endothelial cells in si-ALI, highlighting the GBP2-OTUD5-GPX4 axis as a driver of endothelial ferroptosis and lung injury. Targeting this signaling axis presents a potential therapeutic strategy for si-ALI.

MicroRNAs in transplant rejection: Emerging roles in immune regulation and applications

Organ transplantation is the only effective treatment for patients with end-stage organ failure. Although modern immunosuppressive protocols are very effective and improve quality of life, there is still a need for improvements to eliminate their side effects and to induce transplantation tolerance to allografts. The microRNAs (miRNAs) emerged as promising candidates for regulations of several immune functions. The most advanced research of miRNAs documented that several miRNAs form very complex regulatory networks involved in fine and precise mechanisms of multiple pathophysiological process in cells. This review describes the origin of miRNAs and their action mechanisms by which they regulate several immune and cell biology processes, highlighting the fast progress of miRNA research involved in transplant rejection, recent clinical trials, and describing prospects and possible limitations.

Integrating Transcriptomic and Proteomic Data: IL-27B as a Key Protein in the Development of Septic Cardiomyopathy-A Retrospective Study

BACKGROUND

Septic cardiomyopathy (SCM) is a potentially fatal complication of sepsis. In this study, transcriptomic and proteomic analyzes of serum samples from sepsis patients were conducted to uncover the underlying pathological mechanisms and identify potential therapeutic targets for SCM.

METHODS

This retrospective, dual-center study investigated the progression of sepsis to SCM in patients admitted to intensive care units. A total of 50 patients were enrolled and divided into two groups: sepsis with cardiomyopathy (25 cases) and sepsis without cardiomyopathy (25 cases). Co-expression network analysis was employed to elucidate the biological significance of differentially expressed proteins. By integrating proteomic and transcriptomic data, molecular networks were constructed to visualize interactions among key molecules, aiming to enhance data interpretation and support the study's findings.

RESULTS

Proteomic analysis identified 216 differentially expressed proteins (Fold change > 1.5, p-value < 0.05) between the two groups. Transcriptomic analysis revealed two proteins, including Interleukin-27 subunit beta (IL-27B) and carbonic anhydrase, co-downregulated in patients with septic cardiomyopathy. IL-27B was associated with the immune response, and Kyoto Encyclopedia of Genes and Genomes (KEGG) pathway enrichment analysis indicated its involvement in the cytokine-cytokine receptor interaction signaling pathway.

CONCLUSION

Comprehensive integrated transcriptomic and proteomic analyzes identified significant changes in protein expression associated with SCM, primarily associated with inflammation-related pathways and amino acid metabolism. These findings provide new insights into the pathological mechanisms of SCM and highlight potential therapeutic targets for its treatment.

TRIAL REGISTRATION

The Clinical Research Ethics Committee of Taizhou Hospital of Zhejiang Province affiliated to Wenzhou Medical University approved this study, and written informed consent was given by all patients or their legal representatives. (NO.K20201110).

Machine learning-driven prediction model for cuproptosis-related genes in spinal cord injury: construction and experimental validation

Introduction

Spinal cord injury (SCI) severely affects the central nervous system. Copper homeostasis is closely related to mitochondrial regulation, and cuproptosis is a novel form of cell death associated with mitochondrial metabolism. This study aimed to explore the relationship between SCI and cuproptosis and construct prediction models.

Methods

Gene expression data of SCI patient samples from the GSE151371 dataset were analyzed. The differential expression and correlation of 13 cuproptosis-related genes (CRGs) between SCI and non-SCI samples were identified, and the ssGSEA algorithm was used for immunological infiltration analysis. Unsupervised clustering was performed based on differentially expressed CRGs, followed by weighted gene co-expression network analysis (WGCNA) and enrichment analysis. Three machine learning models (RF, LASSO, and SVM) were constructed to screen candidate genes, and a Nomogram model was used for verification. Animal experiments were carried out on an SCI rat model, including behavioral scoring, histological staining, electron microscopic observation, and qRT-PCR.

Results

Seven CRGs showed differential expression between SCI and non-SCI samples, and there were significant differences in immune cell infiltration levels. Unsupervised clustering divided 38 SCI samples into two clusters (Cluster C1 and Cluster C2). WGCNA identified key modules related to the clusters, and enrichment analysis showed involvement in pathways such as the Ribosome and HIF-1 signaling pathway. Four candidate genes (SLC31A1, DBT, DLST, LIAS) were obtained from the machine learning models, with SLC31A1 performing best (AUC = 0.958). Animal experiments confirmed a significant decrease in the behavioral scores of rats in the SCI group, pathological changes in tissue sections, and differential expression of candidate genes in the SCI rat model.

Discussion

This study revealed a close association between SCI and cuproptosis. Abnormal expression of the four candidate genes affects mitochondrial function, energy metabolism, oxidative stress, and the immune response, which is detrimental to the recovery of neurological function in SCI. However, this study has some limitations, such as unidentified SRGs, a small sample size. Future research requires more in vitro and in vivo experiments to deeply explore regulatory mechanisms and develop intervention methods.

Exosome-shuttled miR-5121 from A2 astrocytes promotes BSCB repair after traumatic SCI by activating autophagy in vascular endothelial cells

Spinal cord injury (SCI) is a severe neurological disorder that significantly impacts patients' quality of life. Following SCI, the blood-spinal cord barrier (BSCB) is destroyed, leading to ischemia and hypoxia, which further exacerbates the imbalance in the spinal cord microenvironment. A2-type astrocytes, which arise under ischemic and hypoxic conditions, have been reported to promote SCI repair. However, the roles of exosomes derived from A2 astrocytes (A2-Exos) in SCI have not been explored. This study aims to investigate the role of A2-Exos in SCI repair, particularly in BSCB restoration, and to elucidate its potential mechanisms. GEO database analysis, western blotting, and immunofluorescence were used to detect A2 astrocyte polarization after SCI in mice. In vitro, A2 astrocytes were obtained through hypoxia induction, and A2-Exos were extracted via ultracentrifugation. An in vivo SCI model and a series of in vitro experiments demonstrated the reparative effects of A2-Exos on BSCB following SCI. Furthermore, miRNA sequencing analysis and rescue experiments confirmed the role of miRNAs in A2-Exos-mediated BSCB repair. Finally, luciferase assays and western blotting were performed to investigate the underlying mechanisms. The results showed that A2-Exos promote motor function recovery and BSCB repair in mice following SCI. In vitro, A2-Exos facilitated BSCB reconstruction and endothelial cell autophagy. miRNA sequencing identified miR-5121 as the most significantly enriched miRNA in A2-Exos, suggesting its involvement in BSCB repair and autophagy regulation. AKT2 was identified as a potential downstream target of miR-5121. Functional gain- and loss-of-function experiments further validated the miR-5121/AKT2 axis. Finally, we demonstrated that the AKT2/mTOR/p70S6K pathway may mediate the effects of miR-5121 in A2-Exos on BSCB repair.

Tertiary lymphoid structure formation induced by LIGHT-engineered and photosensitive nanoparticles-decorated bacteria enhances immune response against colorectal cancer

Tertiary lymphoid structures (TLSs) are known to enhance the prognosis of patients with colorectal cancer (CRC) by fostering an immunologically active tumor microenvironment (TME). Inducing TLS formation therapeutically holds promise for treating immunologically cold CRC, though it poses technical challenges. Here, we design and fabricate a photosensitive bacterial system named E@L-P/ICG. This system is engineered bacteria internally loaded with the cytokine LIGHT and surface-modified with PLGA/ICG nanoparticles (P/ICG NPs). Once accumulated in orthotopic colonic tumors in mice, E@L-P/ICG generates a mild photothermal effect under laser irradiation due to the photosensitive P/ICG NPs. This photothermal effect triggers the self-rupture of E@L-P/ICG and the death of surrounding tumor cells to release adjuvants and antigens, respectively, which in turn synergistically activate the adaptive immune responses. Furthermore, the cytokine LIGHT released from ruptured E@L-P/ICG stimulates the generation of high endothelial vessels (HEVs), promoting lymphocyte recruitment within the TME. These mechanisms lead to the TLS formation in CRC, which further boosts adaptive immune responses through effective infiltration of T cells and B cells, resulting in effectively inhibited tumor growth and extended survival of mice. Our study shows the potential of the E@L-P/ICG system in photosensitively inducing the TLS formation to treat CRC in clinic.

Identification of Autophagy-Related Genes in Patients with Acute Spinal Cord Injury and Analysis of Potential Therapeutic Targets

Autophagy has been implicated in the pathogenesis and progression of spinal cord injury (SCI); however, its specific mechanisms remain unclear. This study is aimed at identifying potential molecular biomarkers related to autophagy in SCI through bioinformatics analysis and exploring potential therapeutic targets. The mRNA expression profile dataset GSE151371 was obtained from the GEO database, and R software was used to screen for differentially expressed autophagy-related genes (DE-ARGs) in SCI. A total of 39 DE-ARGs were detected in this study. Enrichment analysis, protein-protein interaction (PPI) network, TF-mRNA-miRNA regulatory network analysis, and the DSigDB database were used to investigate the regulatory mechanisms between DE-ARGs and identify potential drugs for SCI. Enrichment analysis revealed associations with autophagy, apoptosis, and cell death. PPI analysis identified the highest-scoring module and selected 10 hub genes to construct the TF-mRNA-miRNA network, revealing regulatory mechanisms. Analysis of the DSigDB database indicated that 1,9-Pyrazoloanthrone may be a potential therapeutic drug. Machine learning algorithms identified 3 key genes as candidate biomarkers. Additionally, immune cell infiltration results revealed significant correlations between PINK1, NLRC4, VAMP3, and immune cell accumulation. Molecular docking simulations revealed that imatinib can exert relatively strong regulatory effects on the three key proteins. Finally, in vivo experimental data revealed that the overall biological process of autophagy was disrupted. In summary, this study successfully identified 39 DE-ARGs and discovered several promising biomarkers, significantly contributing to our understanding of the underlying mechanisms of autophagy in SCI. These findings offer valuable insights for the development of novel therapeutic strategies.

The role of miR-155 in cardiovascular diseases: Potential diagnostic and therapeutic targets

Cardiovascular diseases (CVDs), such as atherosclerotic cardiovascular diseases, heart failure (HF), and acute coronary syndrome, represent a significant threat to global health and impose considerable socioeconomic burdens. The intricate pathogenesis of CVD involves various regulatory mechanisms, among which microRNAs (miRNAs) have emerged as critical posttranscriptional regulators. In particular, miR-155 has demonstrated differential expression patterns across a spectrum of CVD and is implicated in the etiology and progression of arterial disorders. This systematic review synthesizes current evidence on the multifaceted roles of miR-155 in the modulation of genes and pathological processes associated with CVD. We delineate the potential of miR-155 as a diagnostic biomarker and therapeutic target, highlighting its significant regulatory influence on conditions such as atherosclerosis, aneurysm, hypertension, HF, myocardial hypertrophy, and oxidative stress. Our analysis underscores the transformative potential of miR-155 as a target for intervention in cardiovascular medicine, warranting further investigation into its clinical applicability.

Pectolinarin Promotes Functional Recovery after Spinal Cord Injury by Regulating Microglia Polarization Through the PI3K/AKT Signaling Pathway

After spinal cord injury (SCI), microglia polarization plays an important role in spinal cord recovery and axon regeneration. In this study, we conducted mRNA microarrays to identify genes associated with different microglial phenotypes. The results showed a correlation between microglial polarization and the PI3K/AKT signaling pathway, a key regulator of inflammatory responses. In addition, we found that Pectolinarin (PTR) could effectively inhibit lipopolysaccharide (LPS)-induced M1 polarization of microglia and facilitate their transition to the M2 phenotype by directly suppressing the PI3K/AKT signaling pathway. In our established animal model of SCI, it was confirmed that PTR treatment induced microglial polarization towards the M2 phenotype, resulting in reduced fibrous scar formation, enhanced myelin reconstitution, and improved axonal regeneration. In conclusion, targeting the PI3K/AKT signaling pathway with PTR presents a promising new direction for SCI treatment.

Metabolic reprogramming in astrocytes prevents neuronal death through a UCHL1/PFKFB3/H4K8la positive feedback loop

Astrocytic metabolic reprogramming is an adaptation of metabolic patterns to meet increased energy demands, although the role after spinal cord injury (SCI) remains unclear. Analysis of single-cell RNA sequencing (scRNA-seq) data identified an increase in astrocytic glycolysis, while PFKFB3, a key regulator of glycolytic flux, was significantly upregulated following SCI. Loss of PFKFB3 in astrocytes prohibited neuronal energy supply and enhanced neuronal ferroptosis in vitro and expanded infiltration of CD68+ macrophages/microglia, exacerbated neuronal loss, and hindered functional recovery in vivo after SCI. Mechanistically, deubiquitinase UCHL1 plays a crucial role in stabilizing and enhancing PFKFB3 expression by cleaving K48-linked ubiquitin chains. Genetic deletion of Uchl1 inhibited locomotor recovery after SCI by suppression of PFKFB3-induced glycolytic reprogramming in astrocytes. Furthermore, the UCHL1/PFKFB3 axis increased lactate production, leading to enhanced histone lactylation and subsequent transcription of Uchl1 and several genes related to glycolysis, suggesting a glycolysis/H4K8la/UCHL1 positive feedback loop. These findings help to clarify the role of the UCHL1/PFKFB3/H4K8la loop in modulation of astrocytic metabolic reprogramming and reveal a potential target for treatment of SCI.

THBS1 in macrophage-derived exosomes exacerbates cerebral ischemia-reperfusion injury by inducing ferroptosis in endothelial cells

Macrophages play a critical role in the development of acute ischemic stroke (AIS). Cerebral ischemia-reperfusion injury (CIRI) is a pivotal pathological process that exacerbates AIS, with exosomes act as crucial mediators. However, the effects and mechanisms of action of macrophage-derived exosomes on CIRI remain unclear. This study demonstrated that macrophage-derived exosomes induce endothelial ferroptosis and barrier disruption during CIRI. Through proteomic sequencing and the reanalysis of transcriptomic and single-cell sequencing data, thrombospondin-1 (THBS1) was identified as a key exosomal molecule. Elevated THBS1 was observed in exosomes and monocytes from the peripheral blood of patients with AIS in oxygen-glucose deprivation/reoxygenation (OGD/R)-stimulated THP-1 and RAW264.7, in their secreted exosomes, and in macrophages within the brains of transient middle cerebral artery occlusion (tMCAO) mice. Additionally, THBS1 expression in exosomes was positively correlated with vascular barrier injury biomarkers, including MMP-9 and S100B. Modulation of THBS1 in macrophage-derived exosomes affected exosome-induced ferroptosis in endothelial cells. The mechanism by which THBS1 binds directly to OTUD5 and promotes GPX4 ubiquitination was elucidated using RNA interference, adeno-associated virus transfection, and endothelial-specific Gpx4 knockout mice. High-throughput screening of small-molecule compounds targeting THBS1 was performed. Molecular docking, molecular dynamics simulations, and cellular thermal shift assays further confirmed that salvianolic acid B (SAB) has a potent binding affinity for THBS1. SAB treatment inhibited the interaction between THBS1 and OTUD5, leading to reduced GPX4 ubiquitination. Further research revealed that SAB treatment enhanced the cerebral protective effects of THBS1 inhibition. In conclusion, this study explored the role of exosome-mediated signaling between macrophages and cerebral vascular endothelial cells in CIRI, highlighting the THBS1-OTUD5-GPX4 axis as a driver of endothelial ferroptosis and brain injury. Targeting this signaling axis represents a potential therapeutic strategy for treating CIRI.

The Role of Deregulated MicroRNAs in Immune Cells of Sjögren's Disease

The 2024 Nobel Prize in Physiology or Medicine, awarded for the discovery of microRNAs (miRNAs) as essential regulators of gene expression, has spotlighted their pivotal roles in disease processes, including autoimmune conditions such as Sjögren's disease (SD). SD is a chronic autoimmune disease marked by lymphocytic infiltration of exocrine glands, resulting in significant glandular dysfunction and diverse systemic effects. Recent research has revealed that miRNAs play crucial roles in SD pathogenesis, orchestrating immune cell activity, epithelial cell integrity, and the regulation of inflammatory pathways. Dysregulation of specific miRNAs is associated with exacerbated immune responses, glandular damage, epithelial cell dysfunction, and sustained inflammation, positioning these small RNA molecules as central players in disease progression. This review synthesizes current findings on the roles of miRNAs in SD, highlighting how certain miRNAs contribute to immune dysregulation, epithelial dysfunction, and disease chronicity. Additionally, we explore the potential of miRNAs as biomarkers for disease activity, reflecting both immune and epithelial health, and as novel therapeutic targets. By consolidating recent advancements, we aim to offer a comprehensive perspective on the involvement of miRNAs in SD and to underscore the potential for miRNA-based strategies to transform the diagnosis, management, and treatment of SD.

Enhancing cardiac repair post-myocardial infarction: a study on GATM/Gel hydrogel therapeutics

BACKGROUND AND PURPOSE

Significant advancements in therapeutic approaches are imperative to address the prevalent impact of myocardial infarction (MI) on morbidity and mortality rates worldwide. This study explores the therapeutic potential of GATM/Gel hydrogel, focusing on its ability to enhance cardiac repair and functionality after MI through modulation of inflammatory and repair pathways.

EXPERIMENTAL APPROACH

The effects of GATM/Gel hydrogel on cardiac recovery were studied in a murine MI model. HA-CHO and gelatin solutions were mixed in situ using a dual syringe with a static mixing needle, and the resulting hydrogel was applied directly to the epicardium during MI modeling, followed by repositioning of the heart and closure of the thorax. Comprehensive in vivo assessments-including echocardiography, electrocardiography, and histopathological analysis-were combined with molecular techniques such as RT-qPCR, Western blotting, and immunofluorescence to elucidate the underlying mechanisms. Key cellular and molecular changes were tracked, focusing on macrophage polarization, angiogenesis, and modulation of the TNF/TNFR2 signaling pathway.

KEY RESULTS

Employing the GATM/Gel hydrogel led to a substantial improvement in heart function, shown through enhanced ejection fraction and fractional shortening, and reduced infarction size compared to control groups. Mechanistically, the hydrogel promoted the polarization of anti-inflammatory M2 macrophages and stimulated angiogenesis. Moreover, treatment with GATM/Gel hydrogel altered the TNF/TNFR2 pathway, pivotal in mediating inflammatory responses and facilitating myocardial repair. The discoveries highlight the possibility of GATM/Gel hydrogels as an innovative remedy for MI, providing a twofold role in regulating inflammation and fostering recovery.

Role of Microglial Mitophagy in Alleviating Postoperative Cognitive Dysfunction: a Mechanistic Study

Postoperative cognitive dysfunction (POCD), a common complication following anesthesia and surgery, is influenced by hippocampal neuroinflammation and microglial activation. Mitophagy, a process regulating inflammatory responses by limiting the accumulation of damaged mitochondria, plays a significant role. This study aimed to determine whether regulating microglial mitophagy and the cGAS-STING pathway could alleviate cognitive decline after surgery. Exploratory laparotomy was performed to establish a POCD model using mice. Western blotting, immunofluorescence staining, transmission electron microscopy, and mt-Keima assays were used to examine microglial mitophagy and the cGAS-STING pathway. Quantitative polymerase chain reaction (qPCR) was used to detect inflammatory mediators and cytosolic mitochondrial DNA (mtDNA) levels in BV2 cells. Exploratory laparotomy triggered mitophagy and enhanced the cGAS-STING pathway in mice hippocampi. Pharmacological treatment reduced microglial activation, neuroinflammation, and cognitive impairment after surgery. Mitophagy suppressed the cGAS-STING pathway in mice hippocampi. In vitro, microglia-induced inflammation was mediated by mitophagy and the cGAS-STING pathway. Small interfering RNA (siRNA) of PINK1 hindered mitophagy activation and facilitated the cytosolic release of mtDNA, resulting in the initiation of the cGAS-STING pathway and innate immune response. Microglial mitophagy inhibited inflammatory responses via the mtDNA-cGAS-STING pathway inducing microglial mitophagy and inhibiting the mtDNA-cGAS-STING pathway may be an effective therapeutic approach for patients with POCD.

H4K12 Lactylation Activated-Spp1 in Reprogrammed Microglia Improves Functional Recovery After Spinal Cord Injury

BACKGROUND

Spinal cord injury (SCI) is a severe condition leading to significant disability and high mortality. The role of the secreted phosphoprotein 1 (SPP1) signaling pathway in SCI, which is quickly activated after injury, is critical for intercellular communication but remains poorly understood.

AIMS

This study aimed to explore the function and regulatory mechanisms of the SPP1 signaling pathway in SCI and investigate its potential as a therapeutic target for improving functional recovery after injury.

MATERIALS AND METHODS

Single-cell RNA sequencing (scRNA-seq) was employed to identify ligands and receptors of the SPP1 signaling pathway, particularly in microglia/macrophages. Recombinant SPP1 (rSPP1) was used in vitro and in vivo to assess its effects on neuronal maturation, mitochondrial energy in axons, and functional recovery after SCI. Pseudotime analysis was conducted to examine the role of Spp1 in microglial activation and proliferation. DNA-pulldown and in vitro experiments were performed to investigate the upstream regulatory proteins of Spp1.

RESULTS

The SPP1 signaling pathway is primarily localized in microglia after SCI, with rSPP1 promoting neuronal maturation and enhancing mitochondrial function in axons. Injection of rSPP1 into the injured spinal cord resulted in significant improvement in functional recovery. Pseudotime analysis indicated that Spp1 is involved in the activation and proliferation of microglia. Histone H4 lysine 12 lactylation (H4K12la) was found to promote the transcription of Spp1 in reprogrammed microglia postinjury.

DISCUSSION

Our findings reveal a novel regulatory mechanism involving Spp1 in SCI, particularly its role in microglial activation, mitochondrial function, and glycolytic reprogramming. This new insight provides a deeper understanding of its contribution to the injury response.

CONCLUSION

This study uncovers a previously unreported mechanism of Spp1 in SCI, offering a potential therapeutic target for SCI.

Stem Cell-Derived Extracellular Vesicle-Mediated Therapeutic Signaling in Spinal Cord Injury

Mesenchymal stem cell-derived extracellular vesicles (MSC-EVs) have emerged as a promising therapeutic strategy for spinal cord injury (SCI). These nanosized vesicles possess unique properties such as low immunogenicity and the ability to cross biological barriers, making them ideal carriers for delivering bioactive molecules to injured tissues. MSC-EVs have been demonstrated to exert multiple beneficial effects in SCI, including reducing inflammation, promoting neuroprotection, and enhancing axonal regeneration. Recent studies have delved into the molecular mechanisms underlying MSC-EV-mediated therapeutic effects. Exosomal microRNAs (miRNAs) have been identified as key regulators of various cellular processes involved in SCI pathogenesis and repair. These miRNAs can influence inflammation, oxidative stress, and apoptosis by modulating gene expression. This review summarized the current state of MSC-EV-based therapies for SCI, highlighting the underlying mechanisms and potential clinical applications. We discussed the challenges and limitations of translating these therapies into clinical practice, such as inconsistent EV production, complex cargo composition, and the need for targeted delivery strategies. Future research should focus on optimizing EV production and characterization, identifying key therapeutic miRNAs, and developing innovative delivery systems to maximize the therapeutic potential of MSC-EVs in SCI.

Broadening horizons: molecular mechanisms and disease implications of endothelial-to-mesenchymal transition

Endothelial-mesenchymal transition (EndMT) is defined as an important process of cellular differentiation by which endothelial cells (ECs) are prone to lose their characteristics and transform into mesenchymal cells. During EndMT, reduced expression of endothelial adhesion molecules disrupts intercellular adhesion, triggering cytoskeletal reorganization and mesenchymal transition. Numerous studies have proved that EndMT is a multifaceted biological event driven primarily by cytokines such as TGF-β, TNF-α, and IL-1β, alongside signaling pathways like WNT, Smad, MEK-ERK, and Notch. Nevertheless, the exact roles of EndMT in complicated diseases have not been comprehensively reviewed. In this review, we summarize the predominant molecular regulatory mechanisms and signaling pathways that contribute to the development of EndMT, as well as highlight the contributions of a series of imperative non-coding RNAs in curbing the initiation of EndMT. Furthermore, we discuss the significant impact of EndMT on worsening vasculature-related diseases, including cancer, cardiovascular diseases, atherosclerosis, pulmonary vascular diseases, diabetes-associated fibrotic conditions, and cerebral cavernous malformation, providing the implications that targeting EndMT holds promise as a therapeutic strategy to mitigate disease progression.

M1 macrophage-derived exosomes alleviate leukemia by causing mitochondrial dysfunction

Acute myeloid leukemia (AML) is one type of blood cancer that initially has a high cure rate but frequently relapses and leading to death. Therefore, there is an urgent need for innovative AML treatments. The leukemia C1498 cells were co-cultured with M1 macrophage-derived exosomes (M1-exo), and the proliferation and apoptosis of C1498 cells were investigated using CCK-8 and flow cytometry, respectively. qPCR and Western blot were applied to determine the PGAM5 expression in M1-exo treated C1498 cells. The role of M1-exo-derived PGAM5 in mitochondria was examined via fluorescence staining. The anti-inflammatory effects of M1-exo-derived PGAM5 and M1-exo were evaluated by flow cytometry, HE staining, and immunohistochemistry in xenograft and nude mouse tumorigenic models. M1-exo exhibited a potent capability to attenuate C1498 cell proliferation, and induce cell apoptosis. In vivo experimentation demonstrated that administration of M1-exo led to a reduction in leukocyte count, alleviated inflammatory infiltration, decreased liver and spleen weights, and significantly diminished tumor size. PGAM5 was elevated in M1-exo, and knockdown of PGAM5 in C1498 cells and M1-exo enhanced proliferation and reduced apoptosis in C1498 cells. Concurrently, M1-exo-derived PGAM5 decreased mitochondrial membrane potential and increased calcium influx in vitro. In vivo, studies showed that knockdown of PGAM5 in M1-exo elevated liver and spleen weights, augmented tumor size, and intensified hepatic inflammatory infiltration. Our study reveals that M1-exo induces mitochondrial dysfunction against leukemia through PGAM5.

Swertianin Promotes Anti-Tumor activity by facilitating Macrophage M1 polarization via STING signaling

To investigate the mechanism by which swertiamarin (swertianin, SWE) regulates the polarization of tumor microenvironment-associated macrophages to M1 phenotype, thereby exerting anti-tumor effects.SWE promoted the formation of M1 cells and increased the proportion of CD86 + cells in both RAW264.7 and primary monocyte-derived macrophages, while activating the STING-NF-κB pathway. When STING or P65 was knocked out, the effects of SWE were antagonized, inhibiting the formation of CD86 + M1 cells. At the animal level, SWE inhibited tumor growth, activated STING-NF-κB, and promoted the formation of CD86 + cells. STING-KO inhibited the effects of SWE.SWE can activate the STING-NF-κB signal to promote macrophage M1 polarization, playing an anti-tumor role.

Endothelial Foxo1 Phosphorylation Inhibition via Aptamer-Liposome Alleviates OPN-Induced Pathological Vascular Remodeling Following Spinal Cord Injury

Reconstruction of the neurovascular unit is essential for the repair of spinal cord injury (SCI). Nonetheless, detailed documentation of specific vascular changes following SCI and targeted interventions for vascular treatment remains limited. This study demonstrates that traumatic pathological vascular remodeling occurs during the chronic phase of injury, characterized by enlarged vessel diameter, disruption of blood-spinal cord barrier, endothelial-to-mesenchymal transition (EndoMT), and heightened extracellular matrix deposition. After SCI, osteopontin (OPN), a critical factor secreted by immune cells, is indispensable for early vascular regeneration but also contributes to traumatic pathological vascular remodeling. This work further elucidates the mechanism by which OPN influences spinal cord microvascular endothelial cells, involving Akt-mediated Foxo1 phosphorylation. This process facilitates the extranuclear transport of Foxo1 and decreases Smad7 expression, leading to excessive activation of the TGF-β signaling pathway, which ultimately results in EndoMT and fibrosis. Targeted inhibition of Foxo1 phosphorylation through an endothelium-specific aptamer-liposome small molecule delivery system significantly mitigates vascular remodeling, thereby enhancing axon regeneration and neurological function recovery following SCI. The findings offer a novel perspective for drug therapies aimed at specifically targeting pathological vasculature after SCI.

Advances in regulating endothelial-mesenchymal transformation through exosomes

Endothelial-mesenchymal transformation (EndoMT) is the process through which endothelial cells transform into mesenchymal cells, affecting their morphology, gene expression, and function. EndoMT is a potential risk factor for cardiovascular and cerebrovascular diseases, tumor metastasis, and fibrosis. Recent research has highlighted the role of exosomes, a mode of cellular communication, in the regulation of EndoMT. Exosomes from diseased tissues and microenvironments can promote EndoMT, increase endothelial permeability, and compromise the vascular barrier. Conversely, exosomes derived from stem cells or progenitor cells can inhibit the EndoMT process and preserve endothelial function. By modifying exosome membranes or contents, we can harness the advantages of exosomes as carriers, enhancing their targeting and ability to inhibit EndoMT. This review aims to systematically summarize the regulation of EndoMT by exosomes in different disease contexts and provide effective strategies for exosome-based EndoMT intervention.

Yes-Associated Protein Promotes Endothelial-Mesenchymal Transition to Mediate Diabetes Mellitus Erectile Dysfunction by Phosphorylating Smad3

PURPOSE

The main objective of this study is to elucidate the role of endothelial-mesenchymal transition (EndMT) regulated by yes-associated protein (YAP) on diabetes mellitus erectile dysfunction (DMED).

MATERIALS AND METHODS

High concentrations of glucose and palmitic acid (HGP) culturing simulated a diabetic condition in vitro. Cell proliferation, migration, tube formation, and marker gene changes of rat cavernous endothelial cells (RCECs) were measured after YAP overexpression or knockdown. Erectile function and histological outcomes were evaluated in vivo.

RESULTS

Nuclear YAP in RCECs was significantly increased after pretreatment with HGP. YAP overexpression enhanced the cell proliferation (0.236±0.004 vs. 0.148±0.008, p<0.001), migration (1.908±0.099 vs. 1.000±0.116, p<0.001), and tube formation (290.6±10.96 and 21,440.3±762.9 vs. 175.0±24.82 and 13,538.6±1,819.0, p<0.001) compared to the control group. Moreover, the ratios of intracavernous pressure (ICP) to mean arterial pressure (MAP) (0.642±0.051 vs. 0.850±0.070, p<0.05), and smooth muscle to collagen (0.155±0.010 vs. 0.274±0.023, p<0.01) were decreased in rats with YAP overexpression. The effects of HGP on CD31, eNOS, CD34, VE-cadherin, vimentin, α-SMA, and p-Smad3 expression were abrogated by inhibiting YAP in RCECs. YAP knockdown also restored the ICP/MAP (0.597±0.019 vs. 0.346±0.033, p<0.01), smooth muscle/collagen (0.13±0.010 vs. 0.08±0.026, p<0.05) and p-Smad3/Smad3 (1.61±0.291 vs. 3.26±0.332, p<0.01) ratios in type 2 diabetic rats.

CONCLUSIONS

YAP promotes EndMT to impair erectile function in type 2 diabetic rats by phosphorylating Smad3, providing a new strategy for treating DMED.

Microglia overexpressing brain-derived neurotrophic factor promote vascular repair and functional recovery in mice after spinal cord injury

ABSTRACT

Spinal cord injury represents a severe form of central nervous system trauma for which effective treatments remain limited. Microglia is the resident immune cells of the central nervous system, play a critical role in spinal cord injury. Previous studies have shown that microglia can promote neuronal survival by phagocytosing dead cells and debris and by releasing neuroprotective and anti-inflammatory factors. However, excessive activation of microglia can lead to persistent inflammation and contribute to the formation of glial scars, which hinder axonal regeneration. Despite this, the precise role and mechanisms of microglia during the acute phase of spinal cord injury remain controversial and poorly understood. To elucidate the role of microglia in spinal cord injury, we employed the colony-stimulating factor 1 receptor inhibitor PLX5622 to deplete microglia. We observed that sustained depletion of microglia resulted in an expansion of the lesion area, downregulation of brain-derived neurotrophic factor, and impaired functional recovery after spinal cord injury. Next, we generated a transgenic mouse line with conditional overexpression of brain-derived neurotrophic factor specifically in microglia. We found that brain-derived neurotrophic factor overexpression in microglia increased angiogenesis and blood flow following spinal cord injury and facilitated the recovery of hindlimb motor function. Additionally, brain-derived neurotrophic factor overexpression in microglia reduced inflammation and neuronal apoptosis during the acute phase of spinal cord injury. Furthermore, through using specific transgenic mouse lines, TMEM119, and the colony-stimulating factor 1 receptor inhibitor PLX73086, we demonstrated that the neuroprotective effects were predominantly due to brain-derived neurotrophic factor overexpression in microglia rather than macrophages. In conclusion, our findings suggest the critical role of microglia in the formation of protective glial scars. Depleting microglia is detrimental to recovery of spinal cord injury, whereas targeting brain-derived neurotrophic factor overexpression in microglia represents a promising and novel therapeutic strategy to enhance motor function recovery in patients with spinal cord injury.

Advances in Novel Biomaterial-Based Strategies for Spinal Cord Injury Treatment

Spinal cord injury (SCI) is a highly disabling neurological disorder. Its pathological process comprises an initial acute injury phase (primary injury) and a secondary injury phase (subsequent chronic injury). Although surgical, drug, and cell therapies have made some progress in treating SCI, there is no exact therapeutic strategy for treating SCI and promoting nerve regeneration due to the complexity of the pathological SCI process. The development of novel drug delivery systems to treat SCI is expected to significantly impact the individualized treatment of SCI due to its unique and excellent properties, such as active targeting and controlled release. In this review, we first describe the pathological progression of the SCI response, including primary and secondary injuries. Next, we provide a concise overview of newly developed nanoplatforms and their potential application in regulating and treating different pathological processes of SCI. Then, we introduce the existing potential problems and future clinical application perspectives of biomedical engineering-based therapies for SCI.

Exosomal microRNA-363 mediates the destructive effect of M1 macrophages on chondrocytes by repressing G3BP2

M1 polarization of synovial macrophages contributes to cartilage degeneration and osteoarthritis (OA) development. However, limited knowledge is available about how M1 macrophages affect the biological properties of chondrocytes. This study aimed to explore the role of exosomal microRNAs (miRs) released from M1 macrophages in modulating the proliferation and survival of chondrocytes. Through bioinformatic analysis and experimental validation, we indicated that miR-363 was selectively induced in M1 macrophages (CD68+CD80+) but not M2 macrophages (CD68+CD206+). The upregulation of miR-363 in M1 macrophages depended on the activation of STAT1 signaling. Clinically, OA patients had a significantly higher miR-363 level in synovial fluid than control individuals without OA. Functional studies revealed that inhibition of miR-363 blocked the M1 macrophage polarization induced by lipopolysaccharide and IFN-γ. Moreover, exosomal miR-363 released from M1 macrophages significantly suppressed the proliferation and survival and induced inflammatory gene expression in chondrocytes. G3BP2 was identified as a target gene for miR-363 and could be negatively regulated by miR-363. Knockdown of G3BP2 recapitulated the effect of miR-363 overexpression on chondrocytes. Most importantly, enforced expression of G3BP2 attenuated miR-363-induced apoptosis and inflammatory response in chondrocytes. In conclusion, miR-363 plays an indispensable role in M1 macrophage polarization and can be released from M1 macrophages via exosomes to cause chondrocyte injury and inflammation. The miR-363/G3BP2 axis may represent a promising target for the prevention of OA development.

Analysis of macrophage polarization and regulation characteristics in ovarian tissues of polycystic ovary syndrome

Background

Polycystic ovary syndrome (PCOS) can lead to infertility and increase the risk of endometrial cancer. Analyzing the macrophage polarization characteristics in ovarian tissues of PCOS is crucial for clinical treatment.

Methods

We obtained 13 PCOS and nine control ovarian samples from the CEO database and analyzed differentially expressed genes (DEGs). Macrophage polarization-related genes (MPRGs) were sourced from the GeneCards and MSigDB databases. Intersection of DEGs with MPRGs identified DEGs associated with macrophage polarization (MPRDEGs). Gene ontology (GO), Kyoto Encyclopedia of Genes and Genomes (KEGG), and Protein-protein interaction (PPI) Network analysis were conducted on MPRDEGs. Moreover, the top 10 genes from three algorithms were identified as the hub genes of MPRGs. In addition, miRNAs, transcription factors (TFs), and drugs were retrieved from relevant databases for regulatory network analysis of mRNA-miRNA, mRNA-TF, and mRNA-Drug interactions. Immune cell composition analysis between the PCOS and control groups was performed using the CIBERSORT algorithm to calculate correlations across 22 immune cell types.

Results

A total of 13 PCOS samples and nine control ovarian samples were obtained in this study. We identified 714 DEGs between the two groups, with 394 up-regulated and 320 down-regulated. Additionally, we identified 774 MPRGs, from which we derived 30 MPRDEGs by intersecting with DEGs, among which 21 exhibited interaction relationships. GO and KEGG analyses revealed the enrichment of MPRDEGs in five biological processes, five cell components, five molecular functions, and three biological pathways. Immune infiltration analysis indicated a strong positive correlation between activated nature killer (NK) cells and memory B cells, while neutrophils and monocytes showed the strongest negative correlation. Further investigation of MPRDEGs identified nine hub genes associated with 41 TFs, 82 miRNAs, and 44 drugs or molecular compounds. Additionally, qRT-PCR results demonstrated overexpression of the CD163, TREM1, and TREM2 genes in ovarian tissues from the PCOS group.

Conclusion

This study elucidated the polarization status and regulatory characteristics of macrophages in ovarian tissues of the PCOS subjects, confirming significant overexpression of CD163, TREM1, and TREM2. These findings contribute to a deeper understanding of the pathogenesis of PCOS.

Exosomes as therapeutic and drug delivery vehicle for neurodegenerative diseases

Neurodegenerative disorders are complex, progressive, and life-threatening. They cause mortality and disability for millions of people worldwide. Appropriate treatment for neurodegenerative diseases (NDs) is still clinically lacking due to the presence of the blood-brain barrier (BBB). Developing an effective transport system that can cross the BBB and enhance the therapeutic effect of neuroprotective agents has been a major challenge for NDs. Exosomes are endogenous nano-sized vesicles that naturally carry biomolecular cargoes. Many studies have indicated that exosome content, particularly microRNAs (miRNAs), possess biological activities by targeting several signaling pathways involved in apoptosis, inflammation, autophagy, and oxidative stress. Exosome content can influence cellular function in healthy or pathological ways. Furthermore, since exosomes reflect the features of the parental cells, their cargoes offer opportunities for early diagnosis and therapeutic intervention of diseases. Exosomes have unique characteristics that make them ideal for delivering drugs directly to the brain. These characteristics include the ability to pass through the BBB, biocompatibility, stability, and innate targeting properties. This review emphasizes the role of exosomes in alleviating NDs and discusses the associated signaling pathways and molecular mechanisms. Furthermore, the unique biological features of exosomes, making them a promising natural transporter for delivering various medications to the brain to combat several NDs, are also discussed.

Dysregulated MiR-223-5p Modulates Inflammation and Oxidative Stress in Traumatic Spinal Cord Injury

AIM

This study aimed to evaluate the miR-223-5p expression in patients with spinal cord injury (SCI) and to determine its role in the pathogenesis of SCI.

METHODS

The serum miR-223-5p levels were analyzed using quantitative real-time polymerase chain reaction. The diagnostic accuracy of miR-223-5p was evaluated using the receiving operating characteristic curves. LPS-induced PC12 cells were established as an in vitro inflammatory cell model. Cell apoptosis, inflammation and oxidative stress were examined. The SCI rat model was constructed to evaluate the effects of miR-223-5p on inflammatory response and motor function in rats.

RESULTS

MiR-223-5p expression was upregulated in SCI patients. MiR-223-5p expression in the complete SCI group was significantly higher than that in incomplete SCI group. ROC analysis showed that miR-223-5p can distinguish SCI patients from healthy volunteers. In vitro experiments demonstrated that LPS upregulated apoptosis and inflammation in PC12 cells. Treatment with miR-223-5p inhibitor alleviated the changes in LPS-induced PC12 cells . Inhibition of miR-223-5p can alleviate the activation of inflammatory response and the effects of SCI on the motor function in rats.

CONCLUSIONS

MiR-223-5p is a potential diagnostic marker for SCI, and it can promote the SCI progression by regulating nerve cell survival, inflammation, and oxidative stress.

Ginsenoside Rg1 Regulates Immune Microenvironment and Neurological Recovery After Spinal Cord Injury Through MYCBP2 Delivery via Neuronal Cell-Derived Extracellular Vesicles

Spinal cord injury (SCI) is a severe neurological condition that frequently leads to significant sensory, motor, and autonomic dysfunction. This study sought to delineate the potential mechanistic underpinnings of extracellular vesicles (EVs) derived from ginsenoside Rg1-pretreated neuronal cells (Rg1-EVs) in ameliorating SCI. These results demonstrated that treatment with Rg1-EVs substantially improved motor function in spinal cord-injured mice. Rg1-EVs enhance microglial polarization toward the M2 phenotype and repressed oxidative stress, thereby altering immune responses and decreasing inflammatory cytokine secretion. Moreover, Rg1-EVs substantially diminish reactive oxygen species accumulation and enhanced neural tissue repair by regulating mitochondrial function. Proteomic profiling highlighted a significant enrichment of MYCBP2 in Rg1-EVs, and functional assays confirmed that MYCBP2 knockdown counteracted the beneficial effects of Rg1-EVs in vitro and in vivo. Mechanistically, MYCBP2 is implicated in the ubiquitination and degradation of S100A9, thereby promoting microglial M2-phenotype polarization and reducing oxidative stress. Overall, these findings substantiated the pivotal role of Rg1-EVs in neuronal protection and functional recovery following SCI through MYCBP2-mediated ubiquitination of S100A9. This research offers novel mechanistic insights into therapeutic strategies against SCI and supports the clinical potential of Rg1-EVs.

Spinal Cord Injury: From MicroRNAs to Exosomal MicroRNAs

Spinal cord injury (SCI) is an unfortunate experience that may generate extensive sensory and motor disabilities due to the destruction and passing of nerve cells. MicroRNAs are small RNA molecules that do not code for proteins but instead serve to regulate protein synthesis by targeting messenger RNA's expression. After SCI, secondary damage like apoptosis, oxidative stress, inflammation, and autophagy occurs, and differentially expressed microRNAs show a function in these procedures. Almost all animal and plant cells release exosomes, which are sophisticated formations of lipid membranes. These exosomes have the capacity to deliver significant materials, such as proteins, RNAs and lipids, to cells in need, regulating their functions and serving as a way of communication. This new method offers a fresh approach to treating spinal cord injury. Obviously, the exosome has the benefit of conveying the transported material across performing regulatory activities and the blood-brain barrier. Among the exosome cargoes, microRNAs, which modulate their mRNA targets, show considerable promise in the pathogenic diagnosis, process, and therapy of SCI. Herein, we describe the roles of microRNAs in SCI. Furthermore, we emphasize the importance of exosomal microRNAs in this disease.

Wnt signaling pathway in spinal cord injury: from mechanisms to potential applications

Spinal cord injury (SCI) denotes damage to both the structure and function of the spinal cord, primarily manifesting as sensory and motor deficits caused by disruptions in neural transmission pathways, potentially culminating in irreversible paralysis. Its pathophysiological processes are complex, with numerous molecules and signaling pathways intricately involved. Notably, the pronounced upregulation of the Wnt signaling pathway post-SCI holds promise for neural regeneration and repair. Activation of the Wnt pathway plays a crucial role in neuronal differentiation, axonal regeneration, local neuroinflammatory responses, and cell apoptosis, highlighting its potential as a therapeutic target for treating SCI. However, excessive activation of the Wnt pathway can also lead to negative effects, highlighting the need for further investigation into its applicability and significance in SCI. This paper provides an overview of the latest research advancements in the Wnt signaling pathway in SCI, summarizing the recent progress in treatment strategies associated with the Wnt pathway and analyzing their advantages and disadvantages. Additionally, we offer insights into the clinical application of the Wnt signaling pathway in SCI, along with prospective avenues for future research direction.

Acid Neutralization by Composite Lysine Nanoparticles for Spinal Cord Injury Recovery through Mitigating Mitochondrial Dysfunction

After spinal cord injury (SCI), significant alterations in the tissue microenvironment lead to mitochondrial dysfunction, inducing apoptosis and inhibiting the remodeling of neural circuits, thereby impeding recovery. Although previous studies have demonstrated a marked decrease in pH at the injury site, creating an acidic microenvironment, the impact of improving this acidic microenvironment on SCI recovery has not been investigated. This study prepared a lysine@hollow mesoporous silica nanoparticle/gelatin methacrylate (GelMA) (L@H/G) composite hydrogel. The L@H/G composite hydrogel was demonstrated to release lysine and efficiently improve the acidic microenvironment slowly. Significantly, the composite hydrogel reduced cell apoptosis, promoted nerve regeneration, inhibited glial scar formation, and ultimately enhanced motor function recovery in mice with SCI. Mechanistically, the L@H/G hydrogel improved the mitochondrial tricarboxylic acid (TCA) cycle and fatty acid metabolism, restoring energy supply and facilitating mitochondrial function recovery. To the best of our knowledge, this is the first report confirming that improving the acidic microenvironment could promote SCI repair, providing a potential therapeutic strategy for SCI.

Exosomal miR-17-92 Cluster from BMSCs Alleviates Apoptosis and Inflammation in Spinal Cord Injury

Spinal cord injury (SCI) involves neuronal apoptosis and axonal disruption, leading to severe motor dysfunction. Studies indicate that exosomes transport microRNAs (miRNAs) and play a crucial role in intercellular communication. This study aimed to explore whether the bone marrow mesenchymal stem cell (BMSCs)-exosomal miR-17-92 cluster can protect against SCI and to explain the underlying mechanisms. In vivo and in vitro SCI models were established and treated with control exosomes (con-exo) or exosomes derived from BMSCs transfected with miR-17-92 cluster plasmid (miR-17-92-exo). Rat BMSCs were isolated and positive markers were identified by flow cytometry. BMSC-derived exosomes were extracted and verified using transmission electron microscopy (TEM), nanoparticle tracking analysis (NTA), and western blotting. The expression of the miR-17-92 cluster was validated by quantitative reverse transcription PCR (qRT-PCR). Spinal cord function, histopathological changes, apoptotic cells, and inflammatory cytokines release in spinal cord tissues were assessed using the Basso-Beattie-Bresnahan (BBB) score, hematoxylin and eosin (HE) staining, terminal deoxynucleotide transferase (TdT)-mediated dUTP nick-end labeling (TUNEL) staining, enzyme-linked immunosorbent assay (ELISA), and qRT-PCR. In PC12 cells, cell proliferation, apoptosis, apoptosis-related proteins cleaved-Caspase3 expression, and inflammatory factors secretion were analyzed using a cell counting kit-8 (CCK8) assay, flow cytometry, western blotting, and ELISA. Our data revealed that the exosomes were successfully isolated from rat BMSCs. The BMSC-exosomal miR-17-92 cluster improved neural functional recovery after SCI, as evidenced by an increased BBB score, improved pathological damage, reduced neuronal apoptosis, and decreased inflammatory factors release. Additionally, miR-17-92-exo treatment significantly inhibited lipopolysaccharide (LPS)-induced reduction in cell viability, increase in cell apoptosis, and upregulation of inflammatory factors in PC12 cells. The exosomal miR-17-92 cluster derived from BMSCs improved functional recovery and exhibited neuroprotective effects in SCI by alleviating apoptosis and inflammation.

Hydrogen Sulfide can Scavenge Free Radicals to Improve Spinal Cord Injury by Inhibiting the p38MAPK/mTOR/NF-κB Signaling Pathway

Spinal cord injury (SCI) causes irreversible cell loss and neurological dysfunctions. Presently, there is no an effective clinical treatment for SCI. It can be the only intervention measure by relieving the symptoms of patients such as pain and fever. Free radical-induced damage is one of the validated mechanisms in the complex secondary injury following primary SCI. Hydrogen sulfide (H2S) as an antioxidant can effectively scavenge free radicals, protect neurons, and improve SCI by inhibiting the p38MAPK/mTOR/NF-κB signaling pathway. In this report, we analyze the pathological mechanism of SCI, the role of free radical-mediated the p38MAPK/mTOR/NF-κB signaling pathway in SCI, and the role of H2S in scavenging free radicals and improving SCI.

MSC-derived exosomes deliver ZBTB4 to mediate transcriptional repression of ITIH3 in astrocytes in spinal cord injury

BACKGROUND

BMSC-secreted exosomes (BMSC-Exos) have shown potential for promoting behavioral recovery following spinal cord injury (SCI). However, its role in blocking astrocyte activation remains unclear. Thus, this study aimed to determine whether BMSC-Exos impair the function of astrocytes following SCI in mice and to seek the mechanism.

METHODS

BMSC-Exos were collected by ultracentrifugation and identified. The SCI mice were developed by laminectomy combined with spinal cord shock, followed by BMSC-Exos or nerve growth factor (positive control) treatment. HE staining, Nissl staining, and TUNEL were conducted to analyze the pathological structural damage and neuronal damage in the mouse spinal cord. Bioinformatics was used to screen altered molecules under the BMSC-Exos treatment. Effects of BMSC-Exos and changes in ZBTB4 and ITIH3 expression on neuronal damage induced by activated astrocytes in the co-culture system were analyzed by CCK-8 and flow cytometry.

RESULTS

Nerve growth factor and BMSC-Exos promoted motor function recovery, alleviated nerve injury, and reduced apoptosis in mice with SCI. ZBTB4 was enriched in BMSC-Exos and lowly expressed in SCI. Downregulation of ZBTB4 diminished the therapeutic effects of BMSC-Exos against SCI. ITIH3 was a downstream target of ZBTB4. Neurotoxic activation of astrocytes induced neuronal injury, which was alleviated by BMSC-Exos. However, ZBTB4 knockdown overturned the effects of BMSC-Exos in vitro and combined ITIH3 knockdown alleviated the accentuating effects of ZBTB4 knockdown on neuronal injury.

CONCLUSION

BMSC-Exos protected against astrocyte-induced neuronal injury by delivering ZBTB4 to repress ITIH3, ultimately improving motor function in mice with SCI.

Lactate facilitated mitochondrial fission-derived ROS to promote pulmonary fibrosis via ERK/DRP-1 signaling

Idiopathic pulmonary fibrosis (IPF) is a chronic, progressive, fibrotic interstitial lung diseases, which mainly existed in middle-aged and elderly people. The accumulation of reactive oxygen species (ROS) is a common characteristic of IPF. Previous research also shown that lactate levels can be abnormally elevated in IPF patients. Emerging evidence suggested a relationship between lactate and ROS in IPF which needs further elucidation. In this article, we utilized a mouse model of BLM-induced pulmonary fibrosis to detect alterations in ROS levels and other indicators associated with fibrosis. Lactate could induce mitochondrial fragmentation by modulating expression and activity of DRP1 and ERK. Moreover, Increased ROS promoted P65 translocation into nucleus, leading to expression of lung fibrotic markers. Finally, Ulixertinib, Mdivi-1 and Mito-TEMPO, which were inhibitor activity of ERK, DRP1 and mtROS, respectively, could effectively prevented mitochondrial damage and production of ROS and eventually alleviate pulmonary fibrosis. Taken together, these findings suggested that lactate could promote lung fibrosis by increasing mitochondrial fission-derived ROS via ERK/DRP1 signaling, which may provide novel therapeutic solutions for IPF.

The role of small extracellular vesicles and microRNA as their cargo in the spinal cord injury pathophysiology and therapy

Spinal cord injury (SCI) is a devastating condition with a complex pathology that affects a significant portion of the population and causes long-term consequences. After primary injury, an inflammatory cascade of secondary injury occurs, followed by neuronal cell death and glial scar formation. Together with the limited regenerative capacity of the central nervous system, these are the main reasons for the poor prognosis after SCI. Despite recent advances, there is still no effective treatment. Promising therapeutic approaches include stem cells transplantation, which has demonstrated neuroprotective and immunomodulatory effects in SCI. This positive effect is thought to be mediated by small extracellular vesicles (sEVs); membrane-bound nanovesicles involved in intercellular communication through transport of functional proteins and RNA molecules. In this review, we summarize the current knowledge about sEVs and microRNA as their cargo as one of the most promising therapeutic approaches for the treatment of SCI. We provide a comprehensive overview of their role in SCI pathophysiology, neuroprotective potential and therapeutic effect.

Islet-resident macrophage-derived miR-155 promotes β cell decompensation via targeting PDX1

Chronic inflammation is critical for the initiation and progression of type 2 diabetes mellitus via causing both insulin resistance and pancreatic β cell dysfunction. miR-155, highly expressed in macrophages, is a master regulator of chronic inflammation. Here we show that blocking a macrophage-derived exosomal miR-155 (MDE-miR-155) mitigates the insulin resistances and glucose intolerances in high-fat-diet (HFD) feeding and type-2 diabetic db/db mice. Lentivirus-based miR-155 sponge decreases the level of miR-155 in the pancreas and improves glucose-stimulated insulin secretion (GSIS) ability of β cells, thus leading to improvements of insulin sensitivities in the liver and adipose tissues. Mechanistically, miR-155 increases its expression in HFD and db/db islets and is released as exosomes by islet-resident macrophages under metabolic stressed conditions. MDE-miR-155 enters β cells and causes defects in GSIS function and insulin biosynthesis via the miR-155-PDX1 axis. Our findings offer a treatment strategy for inflammation-associated diabetes via targeting miR-155.

MiR-10b-5p Regulates Neuronal Autophagy and Apoptosis Induced by Spinal Cord Injury Through UBR7

This study aimed to explore the effects of miR-10b-5p on autophagy and apoptosis in neuronal cells after spinal cord injury (SCI) and the molecular mechanism. Bioinformatics was used to analyze the differentially expressed miRNAs. The expression of related genes and proteins were detected by real-time fluorescence quantitative polymerase chain reaction (RT-qPCR) and Western blot, respectively. Cell proliferation was detected by 5-ethynyl-2'-deoxyuridine (EdU), and apoptosis was detected by flow cytometry or terminal deoxynucleotidyl transferase-mediated dUTP-biotin nick end labeling assay (TUNEL). Coimmunoprecipitation confirmed the interaction between UBR7 and Wnt1 or Beclin1. Autophagy was detected by the dansylcadaverine (MDC). The Basso Beattie Bresnahan (BBB) score was used to evaluate motor function, and hematoxylin-eosin (H&E) and Nissl staining were used to detect spinal cord tissue repair and neuronal changes. The result shows that the expression of miR-10b-5p was downregulated in the SCI models, and transfection of a miR-10b-5p mimic inhibited neuronal cell apoptosis. MiR-10b-5p negatively regulated the expression of UBR7, and the inhibitory effect of the miR-10b-5p mimic on neuronal cell apoptosis was reversed by overexpressing UBR7. In addition, UBR7 can regulate apoptosis by affecting the Wnt/β-catenin pathway by promoting Wnt1 ubiquitination. Treatment with the miR-10b-5p mimic effectively improved motor function, inhibited neuronal cell apoptosis, and promoted spinal cord tissue repair in SCI rats. Overall, miR-10b-5p can alleviate SCI by downregulating UBR7 expression, inhibiting Wnt/β-catenin signaling pathway ubiquitination to reduce neuronal apoptosis, or inhibiting Beclin 1 ubiquitination to promote autophagy.

The Effect of Glycine and N-Acetylcysteine on Oxidative Stress in the Spinal Cord and Skeletal Muscle After Spinal Cord Injury

Oxidative stress is a frequently occurring pathophysiological feature of spinal cord injury (SCI) and can result in secondary injury to the spinal cord and skeletal muscle atrophy. Studies have reported that glycine and N-acetylcysteine (GlyNAC) have anti-aging and anti-oxidative stress properties; however, to date, no study has assessed the effect of GlyNAC in the treatment of SCI. In the present work, we established a rat model of SCI and then administered GlyNAC to the animals by gavage at a dose of 200 mg/kg for four consecutive weeks. The BBB scores of the rats were significantly elevated from the first to the eighth week after GlyNAC intervention, suggesting that GlyNAC promoted the recovery of motor function; it also promoted the significant recovery of body weight of the rats. Meanwhile, the 4-week heat pain results also suggested that GlyNAC intervention could promote the recovery of sensory function in rats to some extent. Additionally, after 4 weeks, the levels of glutathione and superoxide dismutase in spinal cord tissues were significantly elevated, whereas that of malondialdehyde was significantly decreased in GlyNAC-treated animals. The gastrocnemius wet weight ratio and total antioxidant capacity were also significantly increased. After 8 weeks, the malondialdehyde level had decreased significantly in spinal cord tissue, while reactive oxygen species accumulation in skeletal muscle had decreased. These findings suggested that GlyNAC can protect spinal cord tissue, delay skeletal muscle atrophy, and promote functional recovery in rats after SCI.

L-arginine attenuates Streptococcus uberis-induced inflammation by decreasing miR155 level

L-arginine, as an essential substance of the immune system, plays a vital role in innate immunity. MiR155, a multi-functional microRNA, has gained importance as a regulator of homeostasis in immune cells. However, the immunoregulatory mechanism between L-arginine and miR155 in bacterial infections is unknown. Here, we investigated the potential role of miR155 in inflammation and the molecular regulatory mechanisms of L-arginine in Streptococcus uberis (S. uberis) infections. And we observed that miR155 was up-regulated after infection, accompanying the depletion of L-arginine, leading to metabolic disorders of amino acids and severe tissue damage. Mechanically, the upregulated miR155 mediated by the p65 protein played a pro-inflammatory role by suppressing the suppressor of cytokine signaling 6 (SOCS6)-mediated p65 ubiquitination and degradation. This culminated in a violently inflammatory response and tissue damage. Interestingly, a significant anti-inflammatory effect was revealed in L-arginine supplementation by reducing miR155 production via inhibiting p65. This work firstly uncovers the pro-inflammatory role of miR155 and an anti-inflammatory mechanism of L-arginine in S.uberis infection with a mouse mastitis model. Collectively, we provide new insights and strategies for the prevention and control of this important pathogen, which is of great significance for ensuring human food health and safety.

Deubiquitinase UCHL1 promotes angiogenesis and blood-spinal cord barrier function recovery after spinal cord injury by stabilizing Sox17

Improving the function of the blood-spinal cord barrier (BSCB) benefits the functional recovery of mice following spinal cord injury (SCI). The death of endothelial cells and disruption of the BSCB at the injury site contribute to secondary damage, and the ubiquitin-proteasome system is involved in regulating protein function. However, little is known about the regulation of deubiquitinated enzymes in endothelial cells and their effect on BSCB function after SCI. We observed that Sox17 is predominantly localized in endothelial cells and is significantly upregulated after SCI and in LPS-treated brain microvascular endothelial cells. In vitro Sox17 knockdown attenuated endothelial cell proliferation, migration, and tube formation, while in vivo Sox17 knockdown inhibited endothelial regeneration and barrier recovery, leading to poor functional recovery after SCI. Conversely, in vivo overexpression of Sox17 promoted angiogenesis and functional recovery after injury. Additionally, immunoprecipitation-mass spectrometry revealed the interaction between the deubiquitinase UCHL1 and Sox17, which stabilized Sox17 and influenced angiogenesis and BSCB repair following injury. By generating UCHL1 conditional knockout mice and conducting rescue experiments, we further validated that the deubiquitinase UCHL1 promotes angiogenesis and restoration of BSCB function after injury by stabilizing Sox17. Collectively, our findings present a novel therapeutic target for treating SCI by revealing a potential mechanism for endothelial cell regeneration and BSCB repair after SCI.

In Situ Reaction-Generated Aldehyde-Scavenging Polypeptides-Curcumin Conjugate Nanoassemblies for Combined Treatment of Spinal Cord Injury

The microenvironment after traumatic spinal cord injury (SCI) involves complex pathological processes, including elevated oxidative stress, accumulated reactive aldehydes from lipid peroxidation, excessive immune cell infiltration, etc. Unfortunately, most of current neuroprotection therapies cannot cope with the intricate pathophysiology of SCI, leading to scant treatment efficacies. Here, we developed a facile in situ reaction-induced self-assembly method to prepare aldehyde-scavenging polypeptides (PAH)-curcumin conjugate nanoassemblies (named as PFCN) for combined neuroprotection in SCI. The prepared PFCN could release PAH and curcumin in response to oxidative and acidic SCI microenvironment. Subsequently, PFCN exhibited an effectively neuroprotective effect through scavenging toxic aldehydes as well as reactive nitrogen and oxygen species in neurons, modulating microglial M1/M2 polarization, and down-regulating the expression of inflammation-related cytokines to inhibit neuroinflammation. The intravenous administration of PFCN could significantly ameliorate the malignant microenvironment of injured spinal cord, protect the neurons, and promote the motor function recovery in the contusive SCI rat model.

GTF2H4 regulates partial EndMT via NF-κB activation through NCOA3 phosphorylation in ischemic diseases

Partial endothelial-to-mesenchymal transition (EndMT) is an intermediate phenotype observed in endothelial cells (ECs) undergoing a transition toward a mesenchymal state to support neovascularization during (patho)physiological angiogenesis. Here, we investigated the occurrence of partial EndMT in ECs under hypoxic/ischemic conditions and identified general transcription factor IIH subunit 4 (GTF2H4) as a positive regulator of this process. In addition, we discovered that GTF2H4 collaborates with its target protein excision repair cross-complementation group 3 (ERCC3) to co-regulate partial EndMT. Furthermore, by using phosphorylation proteomics and site-directed mutagenesis, we demonstrated that GTF2H4 was involved in the phosphorylation of receptor coactivator 3 (NCOA3) at serine 1330, which promoted the interaction between NCOA3 and p65, resulting in the transcriptional activation of NF-κB and the NF-κB/Snail signaling axis during partial EndMT. In vivo experiments confirmed that GTF2H4 significantly promoted partial EndMT and angiogenesis after ischemic injury. Collectively, our findings reveal that targeting GTF2H4 is promising for tissue repair and offers potential opportunities for treating hypoxic/ischemic diseases.

Epigenetic mechanism of miR-26b-5p-enriched MSCs-EVs attenuates spinal cord injury

Mesenchymal stem cells (MSCs) and extracellular vesicles (EVs) are promising therapies for the treatment of spinal cord injury (SCI). This study sought to explore the epigenetic mechanism of miR-26b-5p-enriched MSCs-EVs in SCI. MSCs and MSCs-EVs were isolated and characterized. The SCI rat model was established, followed by Basso-Beattie-Bresnahan scoring and H&E staining. In vitro cell models were established in PC12 cells with lipopolysaccharide (LPS) treatment, followed by cell viability evaluation using CCK-8 assay. The levels of miR-26b-5p, lysine demethylase 6A (KDM6A), NADPH oxidase 4 (NOX4), reactive oxygen species (ROS), and inflammatory factors (TNF-α/IL-1β/IL-6) in tissues and cells were detected. The levels of cy3-lablled miR-26b-5p in tissues and cells were observed by confocal microscopy. The binding of miR-26b-5p to KDM6A 3'UTR and the enrichments of KDM6A and H3K27me3 at the NOX4 promoter were analyzed. MSCs-EVs attenuated motor dysfunction, inflammation, and oxidative stress in SCI rats. MSCs-EVs delivered miR-26b-5p into PC12 cells to reduce LPS-induced inflammation and ROS production and enhance cell viability. miR-26b-5p inhibited KDM6A, and KDM6A reduced H3K27me3 at the NOX4 promoter to promote NOX4. Overexpression of KDM6A or NOX4 reversed the alleviative role of MSCs-EVs in SCI or LPS-induced cell injury. Overall, MSCs-EVs delivered miR-26b-5p into cells to target the KDM6A/NOX4 axis and facilitate the recovery from SCI.

Engineered Macrophage Membrane-Coated Nanoparticles with Enhanced CCR2 Expression Promote Spinal Cord Injury Repair by Suppressing Neuroinflammation and Neuronal death

Spinal cord injury (SCI) is a severe neurological disorder characterized by significant disability and limited treatment options. Mitigating the secondary inflammatory response following the initial injury is the primary focus of current research in the treatment of SCI. CCL2 (C─C motif chemokine ligand 2) serves as the primary regulator responsible for inflammatory chemotaxis of the majority of peripheral immune cells, blocking the CCL2-CCR2 (C─C chemokine receptor type 2) axis has shown considerable therapeutic potential for inflammatory diseases, including SCI. In this study, it presents a multifunctional biomimetic nanoplatform (CCR2-MM@PLGA/Cur) specifically designed to target the CCL2-CCR2 axis, which consisted of an engineered macrophage membrane (MM) coating with enhanced CCR2 expression and a PLGA (poly (lactic-co-glycolic acid)) nanoparticle that encapsulated therapeutic drugs. CCR2 overexpression on MM not only enhanced drug-targeted delivery to the injury site, but also attenuated macrophage infiltration, microglia pro-inflammatory polarization, and neuronal apoptosis by trapping CCL2. Consequently, it facilitated neural regeneration and motor function recovery in SCI mice, enabling a comprehensive treatment approach for SCI. The feasibility and efficacy of this platform are confirmed through a series of in vitro and in vivo assays, offering new insights and potential avenues for further exploration in the treatment of SCI.

Regulatory RNAs in immunosenescence

BACKGROUND

Immunosenescence is a multifactorial stress response to different intrinsic and extrinsic insults that cause immune deterioration and is accompanied by genomic or epigenomic perturbations. It is now widely recognized that genes and proteins contributing in the process of immunosenescence are regulated by various noncoding (nc) RNAs, including microRNAs (miRNAs), long ncRNAs, and circular RNAs.

AIMS

This review article aimed to evaluate the regulatore RNAs roles in the process of immunosenescence.

METHODS

We analyzed publications that were focusing on the different roles of regulatory RNAs on the several aspects of immunosenescence.

RESULTS

In the immunosenescence setting, ncRNAs have been found to play regulatory roles at both transcriptional and post-transcriptional levels. These factors cooperate to regulate the initiation of gene expression programs and sustaining the senescence phenotype and proinflammatory responses.

CONCLUSION

Immunosenescence is a complex process with pivotal alterations in immune function occurring with age. The extensive network that drive immunosenescence-related features are are mainly directed by a variety of regulatory RNAs such as miRNAs, lncRNAs, and circRNAs. Latest findings about regulation of senescence by ncRNAs in the innate and adaptive immune cells as well as their role in the immunosenescence pathways, provide a better understanding of regulatory RNAs function in the process of immunosenescence.