Serum exosomal microRNA transcriptome profiling in subacute spinal cord injured rats

Curcumin Changed the Number, Particle Size, and miRNA Profile of Serum Exosomes in Roman Laying Hens under Heat Stress

Exosomes have the ability to transport RNA/miRNAs and possess immune modulatory functions. Heat stress, a significant limiting factor in the poultry industry, can induce oxidative stress and suppress the immune responses of laying hens. In this study, we investigated the expression profiles of serum exosomes and their miRNAs in Roman laying hens who were fed a diet with either 0 or 200 mg/kg curcumin under heat stress conditions. The numbers of exosomes were significantly higher in both the HC (heat stress) and HT (heat stress with 200 mg/kg curcumin) groups compared to the NC (control) group and NT (control with 200 mg/kg curcumin) group (p < 0.05). Additionally, we observed that the most prevalent particle diameters were 68.75 nm, 68.25 nm, 54.25 nm, and 60.25 nm in the NC, NT, HC, and HT groups, respectively. From our sRNA library analysis, we identified a total of 863 unique miRNAs; among them, we screened out for subsequent bioinformatics analysis a total of 328 gga-miRNAs(chicken miRNA from the miRbase database). The KEGG pathways that are associated with target genes which are regulated by differentially expressed miRNAs across all four groups at a p-value < 0.01 included oxidative phosphorylation, protein export, cysteine and methionine metabolism, fatty acid degradation, ubiquitin-mediated proteolysis, and cardiac muscle contraction. The above findings suggest that curcumin could mitigate heat-induced effects on laying hens by altering the miRNA expression profiles of serum exosomes along with related regulatory pathways.

A swift expanding trend of extracellular vesicles in spinal cord injury research: a bibliometric analysis

Extracellular vesicles (EVs) in the field of spinal cord injury (SCI) have garnered significant attention for their potential applications in diagnosis and therapy. However, no bibliometric assessment has been conducted to evaluate the scientific progress in this area. A search of articles in Web of Science (WoS) from January 1, 1991, to May 1, 2023, yielded 359 papers that were analyzed using various online analysis tools. These articles have been cited 10,842 times with 30.2 times per paper. The number of publications experienced explosive growth starting in 2015. China and the United States led this research initiative. Keywords were divided into 3 clusters, including "Pathophysiology of SCI", "Bioactive components of EVs", and "Therapeutic effects of EVs in SCI". By integrating the average appearing year (AAY) of keywords in VoSviewer with the time zone map of the Citation Explosion in CiteSpace, the focal point of research has undergone a transformative shift. The emphasis has moved away from pathophysiological factors such as "axon", "vesicle", and "glial cell" to more mechanistic and applied domains such as "activation", "pathways", "hydrogels" and "therapy". In conclusions, institutions are expected to allocate more resources towards EVs-loaded hydrogel therapy and the utilization of innovative materials for injury mitigation.

Immune response following traumatic spinal cord injury: Pathophysiology and therapies

Traumatic spinal cord injury (SCI) is a devastating condition that is often associated with significant loss of function and/or permanent disability. The pathophysiology of SCI is complex and occurs in two phases. First, the mechanical damage from the trauma causes immediate acute cell dysfunction and cell death. Then, secondary mechanisms of injury further propagate the cell dysfunction and cell death over the course of days, weeks, or even months. Among the secondary injury mechanisms, inflammation has been shown to be a key determinant of the secondary injury severity and significantly worsens cell death and functional outcomes. Thus, in addition to surgical management of SCI, selectively targeting the immune response following SCI could substantially decrease the progression of secondary injury and improve patient outcomes. In order to develop such therapies, a detailed molecular understanding of the timing of the immune response following SCI is necessary. Recently, several studies have mapped the cytokine/chemokine and cell proliferation patterns following SCI. In this review, we examine the immune response underlying the pathophysiology of SCI and assess both current and future therapies including pharmaceutical therapies, stem cell therapy, and the exciting potential of extracellular vesicle therapy.

MiRNAs as Promising Translational Strategies for Neuronal Repair and Regeneration in Spinal Cord Injury

Spinal cord injury (SCI) represents a devastating injury to the central nervous system (CNS) that is responsible for impaired mobility and sensory function in SCI patients. The hallmarks of SCI include neuroinflammation, axonal degeneration, neuronal loss, and reactive gliosis. Current strategies, including stem cell transplantation, have not led to successful clinical therapy. MiRNAs are crucial for the differentiation of neural cell types during CNS development, as well as for pathological processes after neural injury including SCI. This makes them ideal candidates for therapy in this condition. Indeed, several studies have demonstrated the involvement of miRNAs that are expressed differently in CNS injury. In this context, the purpose of the review is to provide an overview of the pre-clinical evidence evaluating the use of miRNA therapy in SCI. Specifically, we have focused our attention on miRNAs that are widely associated with neuronal and axon regeneration. “MiRNA replacement therapy” aims to transfer miRNAs to diseased cells and improve targeting efficacy in the cells, and this new therapeutic tool could provide a promising technique to promote SCI repair and reduce functional deficits.

Application value of biofluid-based biomarkers for the diagnosis and treatment of spinal cord injury

Recent studies in patients with spinal cord injuries (SCIs) have confirmed the diagnostic potential of biofluid-based biomarkers, as a topic of increasing interest in relation to SCI diagnosis and treatment. This paper reviews the research progress and application prospects of recently identified SCI-related biomarkers. Many structural proteins, such as glial fibrillary acidic protein, S100-β, ubiquitin carboxy-terminal hydrolase-L1, neurofilament light, and tau protein were correlated with the diagnosis, American Spinal Injury Association Impairment Scale, and prognosis of SCI to different degrees. Inflammatory factors, including interleukin-6, interleukin-8, and tumor necrosis factor α, are also good biomarkers for the diagnosis of acute and chronic SCI, while non-coding RNAs (microRNAs and long non-coding RNAs) also show diagnostic potential for SCI. Trace elements (Mg, Se, Cu, Zn) have been shown to be related to motor recovery and can predict motor function after SCI, while humoral markers can reflect the pathophysiological changes after SCI. These factors have the advantages of low cost, convenient sampling, and ease of dynamic tracking, but are also associated with disadvantages, including diverse influencing factors and complex level changes. Although various proteins have been verified as potential biomarkers for SCI, more convincing evidence from large clinical and prospective studies is thus required to identify the most valuable diagnostic and prognostic biomarkers for SCI.

Nanoparticles in traumatic spinal cord injury: therapy and diagnosis

Nanotechnology has been previously employed for constructing drug delivery vehicles, biosensors, solar cells, lubricants and as antimicrobial agents. The advancement in synthesis procedure makes it possible to formulate nanoparticles (NPs) with precise control over physico-chemical and optical properties that are desired for specific clinical or biological applications. The surface modification technology has further added impetus to the specific applications of NPs by providing them with desirable characteristics. Hence, nanotechnology is of paramount importance in numerous biomedical and industrial applications due to their biocompatibility and stability even in harsh environments. Traumatic spinal cord injuries (TSCIs) are one of the major traumatic injuries that are commonly associated with severe consequences to the patient that may reach to the point of paralysis. Several processes occurring at a biochemical level which exacerbate the injury may be targeted using nanotechnology. This review discusses possible nanotechnology-based approaches for the diagnosis and therapy of TSCI, which have a bright future in clinical practice.

Improving Diagnostic Workup Following Traumatic Spinal Cord Injury: Advances in Biomarkers

PURPOSE OF REVIEW

Traumatic spinal cord injury (SCI) is a life-changing event with drastic implications for patients due to sensorimotor impairment and autonomous dysfunction. Current clinical evaluations focus on the assessment of injury level and severity using standardized neurological examinations. However, they fail to predict individual trajectories of recovery, which highlights the need for the development of advanced diagnostics. This narrative review identifies recent advances in the search of clinically relevant biomarkers in the field of SCI.

RECENT FINDINGS

Advanced neuroimaging and molecular biomarkers sensitive to the disease processes initiated by the SCI have been identified. These biomarkers range from advanced neuroimaging techniques, neurophysiological readouts, and molecular biomarkers identifying the concentrations of several proteins in blood and CSF samples. Some of these biomarkers improve current prediction models based on clinical readouts. Validation with larger patient cohorts is warranted. Several biomarkers have been identified-ranging from imaging to molecular markers-that could serve as advanced diagnostic and hence supplement current clinical assessments.

Extracellular vesicles in neuroinflammation: Pathogenesis, diagnosis, and therapy

Extracellular vesicles (EVs) are bilayer membrane vesicles and act as key messengers in intercellular communication. EVs can be secreted by both neurons and glial cells in the central nervous system (CNS). Under physiological conditions, EVs contribute to CNS homeostasis by facilitating omnidirectional communication among CNS cell populations. In response to CNS injury, EVs mediate neuroinflammatory responses and regulate tissue damage and repair, thereby influencing the pathogenesis, development, and/or recovery of neuroinflammatory diseases, including CNS autoimmune diseases, neurodegenerative diseases, stroke, CNS traumatic injury, and CNS infectious diseases. The unique ability of EVs to pass through the blood-brain barrier further confers them an important role in the bidirectional communication between the CNS and periphery, and application of EVs enables the diagnosis, prognosis, and therapy of neuroinflammatory diseases in a minimally invasive manner.

Extracellular Vesicles as an Emerging Frontier in Spinal Cord Injury Pathobiology and Therapy

Extracellular vesicles (EVs) are membrane-delimited particles that are secreted by nearly all cell types. EVs mediate crucial physiological functions and pathophysiological processes in the CNS. As carriers of diverse bioactive cargoes (e.g., proteins, lipids, and nucleic acids) that can be modified in response to external stimuli, EVs have emerged as pathological mediators following neurotrauma such as spinal cord injury (SCI). We discuss the roles of endogenous EVs in the CNS as well as crosstalk with peripheral EVs in relation to neurotrauma, with a particular focus on SCI. We then summarize the status of EV-based therapeutic advances in preclinical animal models for these conditions. Finally, we discuss new bioengineering strategies that are poised to enhance CNS-specific therapeutic capabilities of EVs.

MicroRNA-145-Mediated KDM6A Downregulation Enhances Neural Repair after Spinal Cord Injury via the NOTCH2/Abcb1a Axis

Spinal cord injury (SCI) causes a significant physical, emotional, social, and economic burden to millions of people. MicroRNAs are known players in the regulatory circuitry of the neural repair in SCI. However, most microRNAs remain uncharacterized. Here, we demonstrate the neuroprotection of microRNA-145 (miR-145) after SCI in vivo and in vitro. In silico analysis predicted the target gene KDM6A of miR-145. The rat SCI model was developed by weight drop, and lipopolysaccharide- (LPS-) induced PC12 cell inflammatory injury model was also established. We manipulated the expression of miR-145 and/or KDM6A both in vivo and in vitro to explain their roles in rat neurological functional recovery as well as PC12 cell activities and inflammation. Furthermore, we delineated the mechanistic involvement of NOTCH2 and Abcb1a in the neuroprotection of miR-145. According to the results, miR-145 was poorly expressed and KDM6A was highly expressed in the spinal cord tissue of the SCI rat model and LPS-induced PC12 cells. Overexpression of miR-145 protects PC12 cells from LPS-induced cell damage and expedites neurological functional recovery of SCI in rats. miR-145 was validated to target and downregulate the demethylase KDM6A expression, thus abrogating the expression of Abcb1a by promoting the methylation of NOTCH2. Additionally, in vivo findings verified that miR-145 expedites neuroprotection after SCI by regulating the KDM6A/NOTCH2/Abcb1a axis. Taken together, miR-145 confers neuroprotective effects and enhances neural repair after SCI through the KDM6A-mediated NOTCH2/Abcb1a axis.

Low expression of miR-19a-5p is associated with high mRNA expression of diacylglycerol O-acyltransferase 2 (DGAT2) in hybrid tilapia

DGAT2 (acyl CoA:diacylglycerol acyltransferase 2) is a key and rate-limiting enzyme that catalyzes the final step of triglyceride (TG) synthesis. In this study, hybrid tilapia were generated from Nile tilapia (♀) and blue tilapia (♂) crossing. The TG content levels in the liver of these tilapia were measured. The results showed that the TG content was higher in the hybrid tilapia. In addition, protein and mRNA expression levels in the tilapia livers were determined. Higher hepatic mRNA and protein expression of DGAT2 in the hybrid fish was found. A luciferase reporter assay with HEK293T cells revealed that miRNA-19a-5p targeted the 3'UTR of DGAT2, suggesting a direct regulatory mechanism. Using qRT-PCR, we found that DGAT2 mRNA levels had a negative correlation with miRNA-19a-5p expression in Nile tilapia and hybrid. Taken together, these findings provide evidence that miRNA-19a-5p is involved in TG synthesis in the regulation of lipid metabolism in tilapia.

Research progress on the regulatory role of microRNAs in spinal cord injury

Spinal cord injury (SCI) is a severe CNS injury that results in abnormalities in, or loss of, motor, sensory and autonomic nervous function. miRNAs belong to a new class of noncoding RNA that regulates the production of proteins and biological function of cells by silencing translation or interfering with the expression of target mRNAs. Following SCI, miRNAs related to oxidative stress, inflammation, autophagy, apoptosis and many other secondary injuries are differentially expressed, and these miRNAs play an important role in the progression of secondary injuries after SCI. The purpose of this review is to elucidate the differential expression and functional roles of miRNAs after SCI, thus providing references for further research on miRNAs in SCI.

Recent Advances on Extracellular Vesicles in Central Nervous System Diseases

Extracellular vesicles (EVs) are particles released by multiple cells, encapsulated by lipid bilayers and containing a variety of biological materials, including proteins, nucleic acids, lipids and metabolites. With the advancement of separation and characterization methods, EV subtypes and their complex and diverse functions have been recognized. In the central nervous system (CNS), EVs are involved in various physiological and pathological processes, such as regulation of neuronal firing, synaptic plasticity, formation and maintenance of myelin sheath, propagation of neuroinflammation, neuroprotection, and spread and removal of toxic protein aggregates. Activity-dependent alteration of constituents enables EVs to reflect the change of cell and tissue states, and the wide distribution of EVs in biological fluids endows them with potential as diagnostic and prognostic biomarkers for CNS diseases, including neurodegenerative disease, cerebrovascular disease, traumatic brain disease, and brain tumor. Favorable biocompatibility, ability of crossing the blood–brain barrier and protecting contents from degradation, give promising therapeutic effects of EVs, either collected from mesenchymal stem cells culture conditioned media, or designed as drug delivery vehicles loaded with specific agents. In this review, we summarized EVs’ basic biological properties, and mainly focused on their applications in CNS diseases.

Spinal cord injury alters microRNA and CD81+ exosome levels in plasma extracellular nanoparticles with neuroinflammatory potential

Extracellular vesicles (EVs) have been implicated mechanistically in the pathobiology of neurodegenerative disorders, including central nervous system injury. However, the role of EVs in spinal cord injury (SCI) has received limited attention to date. Moreover, technical limitations related to EV isolation and characterization methods can lead to misleading or contradictory findings. Here, we examined changes in plasma EVs after mouse SCI at multiple timepoints (1d, 3d, 7d, 14d) using complementary measurement techniques. Plasma EVs isolated by ultracentrifugation (UC) were decreased at 1d post-injury, as shown by nanoparticle tracking analysis (NTA), and paralleled an overall reduction in total plasma extracellular nanoparticles. Western blot (WB) analysis of UC-derived plasma EVs revealed increased expression of the tetraspanin exosome marker, CD81, between 1d and 7d post-injury. To substantiate these findings, we performed interferometric and fluorescence imaging of single, tetraspanin EVs captured directly from plasma with ExoView®. Consistent with WB, we observed significantly increased plasma CD81+ EV count and cargo at 1d post-injury. The majority of these tetraspanin EVs were smaller than 50 nm based on interferometry and were insufficiently resolved by flow cytometry-based detection. At the injury site, there was enhanced expression of EV biogenesis proteins that were also detected in EVs directly isolated from spinal cord tissue by WB. Surface expression of tetraspanins CD9 and CD63 increased in multiple cell types at the injury site; however, astrocyte CD81 expression uniquely decreased, as demonstrated by flow cytometry. UC-isolated plasma EV microRNA cargo was also significantly altered at 1d post-injury with changes similar to that reported in EVs released by astrocytes after inflammatory stimulation. When injected into the lateral ventricle, plasma EVs from SCI mice increased both pro- and anti-inflammatory gene as well as reactive astrocyte gene expression in the brain cortex. These studies provide the first detailed characterization of plasma EV dynamics after SCI and suggest that plasma EVs may be involved in posttraumatic brain inflammation.