LBO-EMSC Hydrogel Serves a Dual Function in Spinal Cord Injury Restoration via the PI3K-Akt-mTOR Pathway

Research Progress on Treating Spinal Cord Injury by Modulating the Phenotype of Microglia

Spinal cord injury (SCI) is a severe central nervous system disorder with no currently available effective treatment. Microglia are immune cells in the central nervous system that play crucial roles in the SCI occurrence, development, and recovery stages. They exhibit dynamic polarization over time and can switch between classical activation (M1) and alternative activation (M2) phenotypes to respond to environmental stimuli. The M1 phenotype is involved in initiating and sustaining inflammatory responses, while the M2 phenotype exerts anti-inflammatory effects and promotes tissue repair in damaged areas. Inhibiting M1 polarization and promoting M2 polarization have become hotspots in regulating neuroinflammation and treating SCI. This article provides a comprehensive review centered on modulating microglial polarization phenotypes for SCI treatment.

Nasal mucosa-derived mesenchymal stem cells prolonged the survival of septic rats by protecting macrophages from pyroptosis

Sepsis is characterized by an exacerbated inflammatory response, driven by the overproduction of cytokines, a phenomenon known as a cytokine storm. This condition is further compounded by the extensive infiltration of M1 macrophages and the pyroptosis of these cells, leading to immune paralysis. To counteract this, we sought to transition M1 macrophages into the M2 phenotype and safeguard them from pyroptosis. For this purpose, we employed ectodermal mesenchymal stem cells (EMSCs) sourced from the nasal mucosa to examine their impact on both macrophages and septic animal models. The co-culture protocol involving LPS-stimulated rat bone marrow macrophages and EMSCs was employed to examine the paracrine influence of EMSCs on macrophages. The intravenous administration of EMSCs was utilized to observe the enhancement in the survival rate of septic rat models and the protection of associated organs. The findings indicated that EMSCs facilitated M2 polarization of macrophages, which were stimulated by LPS, and significantly diminished levels of pro-inflammatory cytokines and NLRP3. Furthermore, EMSCs notably restored the mitochondrial membrane potential (MMP) of macrophages through paracrine action, eliminated excess reactive oxygen species (ROS), and inhibited macrophage pyroptosis. Additionally, the systemic integration of EMSCs substantially reduced injuries to multiple organs and preserved the fundamental functions of the heart, liver, and kidney in CLP rats, thereby extending their survival.

Platelet Membrane-Coated Curcumin-PLGA Nanoparticles Promote Astrocyte-Neuron Transdifferentiation for Intracerebral Hemorrhage Treatment

Intracerebral hemorrhage (ICH) is a hemorrhagic disease with high mortality and disability rates. Curcumin is a promising drug for ICH treatment due to its multiple biological activities, but its application is limited by its poor watersolubility and instability. Herein, platelet membrane-coated curcumin polylactic-co-glycolic acid (PLGA) nanoparticles (PCNPs) are prepared to achieve significantly improved solubility, stability, and sustained release of curcumin. Fourier transform infrared spectra and X-ray diffraction assays indicate good encapsulation of curcumin within nanoparticles. Moreover, it is revealed for the first time that curcumin-loaded nanoparticles can not only suppress hemin-induced astrocyte proliferation but also induce astrocytes into neuron-like cells in vitro. PCNPs are used to treat rat ICH by tail vein injection, using in situ administration as control. The results show that PCNPs are more effective than curcumin-PLGA nanoparticles in concentrating on hemorrhagic lesions, inhibiting inflammation, suppressing astrogliosis, promoting neurogenesis, and improving motor functions. The treatment efficacy of intravenously administered PCNPs is comparable to that of in situ administration, indicating a good targeting effect of PCNPs on the hemorrhage site. This study provides a potent treatment for hemorrhagic injuries and a promising solution for efficient delivery of water-insoluble drugs using composite materials of macromolecules and cell membranes.

The Medicinal Species of the Lycium Genus (Goji Berries) in East Asia: A Review of Its Effect on Cell Signal Transduction Pathways

Natural plants contain numerous chemical compounds that are beneficial to human health. The berries from the Lycium genus are widely consumed and are highly nutritious. Moreover, their chemical constituents have attracted attention for their health-promoting properties. In East Asia, there are three varieties of the Lycium genus (Lycium barbarum L., Lycium chinense Miller, and L. ruthenicum Murray) that possess medicinal value and are commonly used for treating chronic diseases and improving metabolic disorders. These varieties are locally referred to as "red Goji berries" or "black Goji berries" due to their distinct colors, and they differ in their chemical compositions, primarily in terms of carotenoid and anthocyanin content. The pharmacological functions of these berries include anti-aging, antioxidant, anti-inflammatory, and anti-exercise fatigue effects. This review aims to analyze previous and recent studies on the active ingredients and pharmacological activities of these Lycium varieties, elucidating their signaling pathways and assessing their impact on the gut microbiota. Furthermore, the potential prospects for using these active ingredients in the treatment of COVID-19 are evaluated. This review explores the potential targets of these Lycium varieties in the treatment of relevant diseases, highlighting their potential value in drug development.

Fructus lycii oligosaccharide alleviates acute liver injury via PI3K/Akt/mTOR pathway

Regulating the immune-environment is essential for treating acute liver injury (ALI). However, the deficiency of an effective immune balancer restricted progress. Herein, we reported an oligosaccharide from Fructus lycii oligosaccharide (FLO). To investigate the effects of FLO, we adopted primary macrophages and LO2 for experiments in vitro. In vivo, we assessed the influence of FLO in ALI with histochemical staining and enzyme indicators detection. Following that, we clarified the underlying mechanisms using western blotting and immunofluorescence. Our results indicated that FLO (100 μg/mL) showed apparent inflammatory reversal effects by shifting the phenotype of macrophages from M1 to M2 without causing any cytotoxicity. Furthermore, CCl4-induced mice were significantly improved by FLO intragastric administration. Meanwhile, PI3K/AKT/mTOR pathway was confirmed for the up-regulation of IL-10 via M2 polarization of macrophages. Collectively, our findings highlight the beneficial effects of FLO on ALI therapy via M1 to M2 macrophage conversion.

BM-MSC-Loaded Graphene-Collagen Cryogels Ameliorate Neuroinflammation in a Rat Spinal Cord Injury Model

A major obstacle to axonal regeneration following spinal cord injury (SCI) is neuroinflammation mediated by astrocytes and microglial cells. We previously demonstrated that graphene-based collagen hydrogels alone can decrease neuroinflammation in SCI. Their regenerative potential, however, is poorly understood and incomplete. Furthermore, stem cells have demonstrated both neuroprotective and regenerative properties in spinal cord regeneration, although there are constraints connected with the application of stem cell-based therapy. In this study, we have analyzed the regeneration capability of human bone marrow mesenchymal stem cell (BM-MSC)-loaded graphene-cross-linked collagen cryogels (Gr-Col) in a thoracic (T10-T11) hemisection model of SCI. Our study found that BM-MSC-loaded Gr-Col improves axonal regeneration, reduces neuroinflammation by decreasing astrocyte reactivity, and promotes M2 macrophage polarization. BM-MSC-loaded-Gr-Col demonstrated enhanced regenerative potential compared to Gr-Col and the injury group control. Next-generation sequencing (NGS) analysis revealed that BM-MSC-loaded-Gr-Col modulates the JAK2-STAT3 pathway, thus decreasing the reactive and scar-forming astrocyte phenotype. The decrease in neuroinflammation in the BM-MSC-loaded-Gr-Col group is attributed to the modulation of Notch/Rock and STAT5a/b and STAT6 signaling. Overall, Gene Set Enrichment Analysis suggests the promising role of BM-MSC-loaded-Gr-Col in promoting axonal regeneration after SCI by modulating molecular pathways such as the PI3/Akt pathway, focal adhesion kinase, and various inflammatory pathways.

Polysaccharides as a promising platform for the treatment of spinal cord injury: A review

Spinal cord injury is incurable and often results in irreversible damage to motor function and autonomic sensory abilities. To enhance the effectiveness of therapeutic substances such as cells, growth factors, drugs, and nucleic acids for treating spinal cord injuries, as well as to reduce the toxic side effects of chemical reagents, polysaccharides have been gained attention due to their immunomodulatory properties and the biocompatibility and biodegradability of polysaccharide scaffolds. Polysaccharides hold potential as drug delivery systems in treating spinal cord injuries. This article aims to present an extensive evaluation of the potential applications of polysaccharide materials in scaffold construction, drug delivery, and immunomodulation over the past five years so that offering new directions and opportunities for the treatment of spinal cord injuries.

Activation of the CD200/CD200R1 axis improves cognitive impairment by enhancing hippocampal neurogenesis via suppression of M1 microglial polarization and neuroinflammation in hypoxic-ischemic neonatal rats

Following hypoxic-ischemic brain damage (HIBD), there is a decline in cognitive function; however, there are no effective treatment strategies for this condition in neonates. This study aimed to evaluate the role of the cluster of differentiation 200 (CD200)/CD200R1 axis in cognitive function following HIBD using an established model of HIBD in postnatal day 7 rats. Western blotting analysis was conducted to evaluate the protein expression levels of CD200, CD200R1, proteins associated with the PI3K/Akt-NF-κB pathway, and inflammatory factors such as TNF-α, IL-1β, and IL-6 in the hippocampus. Additionally, double-immunofluorescence labeling was utilized to evaluate M1 microglial polarization and neurogenesis in the hippocampus. To assess the learning and memory function of the experimental rats, the Morris water maze (MWM) test was conducted. HIBDleads to a decrease in the expression of CD200 and CD200R1 proteins in the neonatal rat hippocampus, while simultaneously increasing the expression of TNF-α, IL-6, and IL-1β proteins, ultimately resulting in cognitive impairment. The administration of CD200Fc, a fusion protein of CD200, was found to enhance the expression of p-PI3K and p-Akt, but reduce the expression of p-NF-κB. Additionally, CD200Fc inhibited M1 polarization of microglia, reduced neuroinflammation, improved hippocampal neurogenesis, and mitigated cognitive impairment caused by HIBD in neonatal rats. In contrast, blocking the interaction between CD200 and CD200R1 with the anti-CD200R1 antibody (CD200R1 Ab) exerted the opposite effect. Furthermore, the PI3K specific activator, 740Y-P, significantly increased the expression of p-PI3K and p-Akt, but reduced p-NF-κB expression. It also inhibited M1 polarization of microglia, reduced neuroinflammation, and improved hippocampal neurogenesis and cognitive function in neonatal rats with HIBD. Our findings illustrate that activation of the CD200/CD200R1 axis inhibits the NF-κB-mediated M1 polarization of microglia to improve HIBD-induced cognitive impairment and hippocampal neurogenesis disorder via the PI3K/Akt signaling pathway.

Recent progress and challenges in the treatment of spinal cord injury

Spinal cord injury (SCI) disrupts the structural and functional connectivity between the higher center and the spinal cord, resulting in severe motor, sensory, and autonomic dysfunction with a variety of complications. The pathophysiology of SCI is complicated and multifaceted, and thus individual treatments acting on a specific aspect or process are inadequate to elicit neuronal regeneration and functional recovery after SCI. Combinatory strategies targeting multiple aspects of SCI pathology have achieved greater beneficial effects than individual therapy alone. Although many problems and challenges remain, the encouraging outcomes that have been achieved in preclinical models offer a promising foothold for the development of novel clinical strategies to treat SCI. In this review, we characterize the mechanisms underlying axon regeneration of adult neurons and summarize recent advances in facilitating functional recovery following SCI at both the acute and chronic stages. In addition, we analyze the current status, remaining problems, and realistic challenges towards clinical translation. Finally, we consider the future of SCI treatment and provide insights into how to narrow the translational gap that currently exists between preclinical studies and clinical practice. Going forward, clinical trials should emphasize multidisciplinary conversation and cooperation to identify optimal combinatorial approaches to maximize therapeutic benefit in humans with SCI.

Modulating neuroinflammation through molecular, cellular and biomaterial-based approaches to treat spinal cord injury

The neuroinflammatory response that is elicited after spinal cord injury contributes to both tissue damage and reparative processes. The complex and dynamic cellular and molecular changes within the spinal cord microenvironment result in a functional imbalance of immune cells and their modulatory factors. To facilitate wound healing and repair, it is necessary to manipulate the immunological pathways during neuroinflammation to achieve successful therapeutic interventions. In this review, recent advancements and fresh perspectives on the consequences of neuroinflammation after SCI and modulation of the inflammatory responses through the use of molecular-, cellular-, and biomaterial-based therapies to promote tissue regeneration and functional recovery will be discussed.

Cerebrospinal fluid-derived extracellular vesicles after spinal cord injury promote vascular regeneration via PI3K/AKT signaling pathway

Background

The cerebrospinal fluid (CSF), which surrounds the brain and spinal cord, is predominantly produced by the choroid plexus of the ventricle. Although CSF-derived extracellular vesicles (CSF-EVs) may be utilized as diagnostic and prognostic indicators for illnesses of the central nervous system (CNS), it is uncertain if CSF-EVs may have an impact on neurological function after spinal cord injury (SCI).

Methods

Here, we isolated EVs using ultracentrifugation after extracting CSF from Bama miniature pigs. We then combined CSF-EVs with hydrogel and put it on the spinal cord's surface. To determine if CSF-EVs had an impact on mice's neurofunctional recovery, behavioral evaluations were employed. Both in vitro and in vivo, the effect of CSF-EVs on angiogenesis was assessed. We investigated whether CSF-EVs stimulated the PI3K/AKT pathway to alter angiogenesis using the PI3K inhibitor LY294002.

Results

CSF-EVs were successfully isolated and identified by transmission electron microscope (TEM), nano-tracking analysis (NTA), and western blot. CSF-EVs could be ingested by vascular endothelial cells as proved by in vivo imaging and immunofluorescence. We demonstrated that CSF-EVs derived from pigs with SCI (SCI-EVs) showed a better effect on promoting vascular regeneration as compared to CSF-EVs isolated from pigs receiving laminectomy (Sham-EVs). Behavioral assessments demonstrated that SCI-EVs could dramatically enhance motor and sensory function in mice with SCI. Western blot analysis suggested that SCI-EVs promote angiogenesis by activating PI3K/AKT signaling pathway, and the pro-angiogenetic effect of SCI-EVs was attenuated by the application of the LY294002 (PI3K inhibitor).

Conclusion

Our study revealed that CSF-EVs could enhance vascular regeneration by activating the PI3K/AKT pathway, hence improving motor function recovery after SCI, which may offer potential novel therapeutic options for acute SCI.

The translational potential of this article

This study demonstrated the promotion of vascular regeneration and neurological function of CSF-derived exosomes, which may provide a potential therapeutic approach for the treatment of spinal cord injury.

Advanced Therapies for Traumatic Central Nervous System Injury: Delivery Strategy Reinforced Efficient Microglial Manipulation

Traumatic central nervous system (CNS) injuries, including spinal cord injury and traumatic brain injury, are challenging enemies of human health. Microglia, the main component of the innate immune system in CNS, can be activated postinjury and are key participants in the pathological procedure and development of CNS trauma. Activated microglia can be typically classified into pro-inflammatory (M1) and anti-inflammatory (M2) phenotypes. Reducing M1 polarization while promoting M2 polarization is thought to be promising for CNS injury treatment. However, obstacles such as the low permeability of the blood-brain barrier and short retention time in circulation limit the therapeutic outcomes of administrated drugs, and rational delivery strategies are necessary for efficient microglial regulation. To this end, proper administration methods and delivery systems like nano/microcarriers and scaffolds are investigated to augment the therapeutic effects of drugs, while some of these delivery systems have self-efficacies in microglial manipulation. Besides, systems based on cell and cell-derived exosomes also show impressive effects, and some underlying targeting mechanisms of these delivery systems have been discovered. In this review, we introduce the roles of microglia play in traumatic CNS injuries, discuss the potential targets for the polarization regulation of microglial phenotype, and summarize recent studies and clinical trials about delivery strategies on enhancing the effect of microglial regulation and therapeutic outcome, as well as targeting mechanisms post CNS trauma.

Olfactory mucosa tissue-derived mesenchymal stem cells lysate ameliorates LPS-induced acute liver injury in mice

Background

Acute liver injury (ALI) induced by sepsis seriously endangers the health of human beings every year. Mesenchymal stem cells (MSCs) lysate containing various regulators had a positive effect on anti-inflammation, hoping to provide a promising strategy in ALI.

Methods

Olfactory mucosa-derived mesenchymal stem cells (OM-MSCs) were extracted and identified. The collected OM-MSCs were prepared after repeated freeze–thaw in phosphate buffer solution (PBS). Then, OM-MSCs lysate was filtered for future experiments. To understand the composes of OM-MSCs clearly, we detected the components of OM-MSCs lysate by western blotting. In vitro, OM-MSCs lysate was applied to evaluate the effects on normal human liver cells (LO-2) under stimulation of LPS. Lipopolysaccharide (LPS) was also injected intraperitoneally to build ALI model in mice. We further assessed the anti-inflammatory capacity of OM-MSCs lysate on ALI in vivo by aminotransferase determination, pathology observation, and immunohistochemical staining. Moreover, the immunoblot technique was performed to recognize the changes in inflammatory factors and related proteins.

Results

In this study, we found that OM-MSCs lysate could protect structure effectively, improve the plasma aminotransferases, diminish inflammation by releasing interleukin-10 (IL-10) and transforming growth factor-beta (TGF-β). A significant decrease in tumor necrosis factor-α (TNF-α) also occurred under the treatment of OM-MSCs lysate. In addition, trophic factors originating from OM-MSCs lysate provided a supportive micro-environment for liver recovery. Especially, up-expression of vascular endothelial growth factor (VEGF) in vivo revealed that OM-MSCs might have a great potential for healing.

Conclusions

Our results demonstrated that OM-MSCs lysate could alleviate LPS-induced ALI via decreasing inflammatory cytokines and promoting recovery.

Thermo-sensitive hydrogel combined with SHH expressed RMSCs for rat spinal cord regeneration

Purpose: Spinal cord injury (SCI) has a damaging impact on patients, amid being a worldwide problem with no effective treatment. Herein, we reported a method for functional therapy of SCI in rats, wherein we combined thermo-sensitive hydrogel with Sonic Hedgehog (SHH) expressed in rat bone-marrow derived mesenchymal stem cells (RMSCs).

Methods: Bone marrow-derived mesenchymal stem cells (BMSCs) were isolated from Sprague-Dawley (SD) female rats. The SHH was optimized and transferred into RMSCs via cationic liposomes, while thermo-sensitive hydrogel was reformed with hyaluronate (HA) and Pluronic F127. Then, a rat model with SCI was established accordingly by male SD rats and randomized into sham, model, RMSCs with hydrogel and SHH-RMSCs with hydrogel. The evaluation of SCI repair based on Basso, Beattie Bresnahanlocomotor rating scale (BBB scale) and inclined plate score. Immunofluorescence, immunohistochemistry and hematoxylin-eosin were utilized to explore the expression of protein (GFAP, GAP43, NF200 and MBP) and histopathology.

Results: It was demonstrated that transfection of SHH with cationic liposomes exhibited more effect in RMSCs than lipofectamine 2000. As shown in SEM, 3.5% HA-F127 demonstrated porous structure. In the MTT and dead/live assay, 3.5% HA-F127 showed good biocompatibility for RMSCs. Both RMSCs and SHH-RMSCs groups could significantly promote BBB and inclined plate scores (p < 0.01) compared with the model. Furthermore, the SHH-RMSC group was significantly improved than RMSC with the expression of related proteins, where NF200, MBP, and GAP43 were principally enhanced with the GFAP expression being virtually down-regulated.

Conclusion: All in all, the results suggested that transplantation of RMSCs with SHH could improve the function of SCI and promote nerve regeneration.