Quercetin prevents necroptosis of oligodendrocytes by inhibiting macrophages/microglia polarization to M1 phenotype after spinal cord injury in rats

Pharmacological targeting cGAS/STING/NF-κB axis by tryptanthrin induces microglia polarization toward M2 phenotype and promotes functional recovery in a mouse model of spinal cord injury

JOURNAL/nrgr/04.03/01300535-202511000-00031/figure1/v/2024-12-20T164640Z/r/image-tiff The M1/M2 phenotypic shift of microglia after spinal cord injury plays an important role in the regulation of neuroinflammation during the secondary injury phase of spinal cord injury. Regulation of shifting microglia polarization from M1 (neurotoxic and proinflammatory type) to M2 (neuroprotective and anti-inflammatory type) after spinal cord injury appears to be crucial. Tryptanthrin possesses an anti-inflammatory biological function. However, its roles and the underlying molecular mechanisms in spinal cord injury remain unknown. In this study, we found that tryptanthrin inhibited microglia-derived inflammation by promoting polarization to the M2 phenotype in vitro . Tryptanthrin promoted M2 polarization through inactivating the cGAS/STING/NF-κB pathway. Additionally, we found that targeting the cGAS/STING/NF-κB pathway with tryptanthrin shifted microglia from the M1 to M2 phenotype after spinal cord injury, inhibited neuronal loss, and promoted tissue repair and functional recovery in a mouse model of spinal cord injury. Finally, using a conditional co-culture system, we found that microglia treated with tryptanthrin suppressed endoplasmic reticulum stress-related neuronal apoptosis. Taken together, these results suggest that by targeting the cGAS/STING/NF-κB axis, tryptanthrin attenuates microglia-derived neuroinflammation and promotes functional recovery after spinal cord injury through shifting microglia polarization to the M2 phenotype.

Pyroptosis, ferroptosis, and autophagy in spinal cord injury: regulatory mechanisms and therapeutic targets

Regulated cell death is a form of cell death that is actively controlled by biomolecules. Several studies have shown that regulated cell death plays a key role after spinal cord injury. Pyroptosis and ferroptosis are newly discovered types of regulated cell deaths that have been shown to exacerbate inflammation and lead to cell death in damaged spinal cords. Autophagy, a complex form of cell death that is interconnected with various regulated cell death mechanisms, has garnered significant attention in the study of spinal cord injury. This injury triggers not only cell death but also cellular survival responses. Multiple signaling pathways play pivotal roles in influencing the processes of both deterioration and repair in spinal cord injury by regulating pyroptosis, ferroptosis, and autophagy. Therefore, this review aims to comprehensively examine the mechanisms underlying regulated cell deaths, the signaling pathways that modulate these mechanisms, and the potential therapeutic targets for spinal cord injury. Our analysis suggests that targeting the common regulatory signaling pathways of different regulated cell deaths could be a promising strategy to promote cell survival and enhance the repair of spinal cord injury. Moreover, a holistic approach that incorporates multiple regulated cell deaths and their regulatory pathways presents a promising multi-target therapeutic strategy for the management of spinal cord injury.

Effect of microglial Pd1 on glial scar formation after spinal cord injury in mice

The cross talk between microglia and astrocytes following spinal cord injury (SCI) greatly decides the prognosis. However, a comprehensive understanding of the molecular mechanisms by which microglia regulate astrocytic activity post-SCI is lacking. Programmed cell death protein 1 (Pdcd1, Pd1) plays a crucial role in modulating immune responses by exerting suppressive effects on microglia and peripheral immune cells within the central nervous system. Previous studies have shown the involvement of Pd1 in the pathogenesis of SCI; however, the role of microglial Pd1 in astrocytic activation and the following glial scar formation remains elusive. Here, we demonstrated that the pharmacological depletion of microglia using minocycline decreased the expression of tumor necrosis factor-alpha and interleukin-6 while concurrently increasing the expression of interleukin-10 following SCI, thereby facilitating motor function recovery in mice. We observed an increase in Pd1 expression in the injured spinal cord after SCI, with precise localization of Pd1 within microglia. Based on Pd1 knockout (KO) mice, we further revealed that Pd1 deficiency disrupted glial scar formation, leading to increased inflammation, impeded nerve regeneration, enlarged tissue damage, and compromised functional recovery following SCI. In vitro study showed that siRNA-mediated inhibition of Pd1 in microglia followed by lipopolysaccharide treatment significantly inhibited astrocyte migration and upregulated the secretion of tumor necrosis factor-alpha and CXCL9 from microglia, indicating that microglial Pd1 regulates glial scar formation through modulating the inflammatory microenvironment. Our study gains a new mechanistic insight into how microglial Pd1 decides the fate of SCI and promotes microglial Pd1 as a promising therapeutic target for SCI.

GPx3 Promotes Functional Recovery after Spinal Cord Injury by Inhibiting Microglial Pyroptosis Through IRAK4/ROS/NLRP3 Axis

Aim: Spinal cord injury (SCI) is a catastrophic injury characterized by oxidative stress. Glutathione peroxidase 3 (GPx3) is an antioxidant enzyme that protects against immune responses in various diseases. However, the effects of GPx3 in SCI remains unclear. This study aimed to investigate the role of GPx3 in SCI and its underlying mechanisms. Results: We injected adeno-associated viruses to overexpress GPx3 in mice. Primary microglia and BV2 cells were used as in vitro models. We knocked down or overexpressed GPx3 in BV2 cells. Additionally, BV2 cells transfected with siIRAK4 were used to perform rescue experiments. A series of histological and molecular biological analyses were used to explore the role of GPx3 in SCI. Overexpression of GPx3 inhibited oxidative stress in mice, improving functional recovery after SCI. Similarly, LPS+ATP stimulation decreased GPx3 expression in microglia. Silencing of GPx3 elevated the generation of reactive oxygen species, increased the expression of IRAK4 and pro-inflammatory factors, and promoted pyroptosis in microglia. However, overexpression of GPx3 reversed these results. Moreover, silencing of IRAK4 alleviated these phenomena, which were upregulated by GPx3 deficiency. Innovation and Conclusion: Our results demonstrated that GPx3 plays a critical role in SCI by inhibiting microglial pyroptosis via the IRAK4/ROS/NLRP3 signaling pathway. Antioxid. Redox Signal. 42, 711-729.

( +)-Catechin Alleviates CCI-Induced Neuropathic Pain by Modulating Microglia M1 and M2 Polarization via the TLR4/MyD88/NF-κB Signaling Pathway

The aim of this research endeavor was to explore the therapeutic potential of ( +)-catechin in mitigating neuropathic pain. A total of thirty-two Sprague‒Dawley rats were randomly allocated into four groups: the sham group, the chronic constriction injury (CCI) group, the CCI + ibuprofen group, and the CCI + ( +)-catechin group. The results of the in vivo experiment show that ( +)-catechin has the potential to improve mechanical hyperalgesia induced by CCI and reduce the infiltration of inflammatory cells in the injured sciatic nerve. CCI induces the upregulation of nNOS, iNOS, IL-1β, and COX-2 within the rat sciatic nerve and leads to an elevation in the levels of IL-1β, PGE2, and TNF-α in the serum of rats, while simultaneously diminishing the secretion of IL-10. Moreover, immunofluorescence analysis reveals that CCI enhances the expression of CD32 (an M1 polarization marker) in the rat spinal cord, while diminishing the expression of CD206 (an M2 polarization marker). However, the administration of ( +)-catechin effectively counteracts these effects. Western blot analysis further demonstrates that ( +)-catechin significantly reduces the protein expression of IBA-1, IL-1β, MyD88, p-NF-κB, p-JNK, p-ERK, p-p38MAPK, COX-2, and TLR4 within the spinal cord. The findings of the BV2 cell experiment revealed the attenuating effects of ( +)-catechin on M1 polarization markers (such as IL-1β, TNF-α, iNOS, and CD32), while concurrently boosting the levels of M2 polarization markers (including CD206, IL-10, and Arg-1). Notably, administration of LPS significantly heightened the accumulation of IBA-1, IL-1β, MyD88, p-NF-κB, p-JNK, p-ERK, p-p38MAPK, TLR4, COX-2, and iNOS, while concurrently suppressing Arg-1 expression. However, the administration of ( +)-catechin effectively reversed these alterations. Overall, these findings suggest that ( +)-catechin alleviates neuropathic pain by modulating the M1 and M2 phenotypes of microglia through the TLR4/MyD88/NF-κB pathway.

An engineering-reinforced extracellular vesicle-integrated hydrogel with an ROS-responsive release pattern mitigates spinal cord injury

The local delivery of mesenchymal stem cell-derived extracellular vesicles (EVs) via hydrogel has emerged as an effective approach for spinal cord injury (SCI) treatment. However, achieving on-demand release of EVs from hydrogel to address dynamically changing pathology remains challenging. Here, we used a series of engineering methods to further enhance EVs' efficacy and optimize their release pattern from hydrogel. Specifically, the pro-angiogenic, neurotrophic, and anti-inflammatory effects of EVs were reinforced through three-dimensional culture and dexamethasone (Dxm) encapsulation. Then, the prepared Dxm-loaded 3EVs (3EVs-Dxm) were membrane modified with ortho-dihydroxy groups (-2OH) and formed an EV-integrated hydrogel (3EVs-Dxm-Gel) via the cross-link with phenylboronic acid-modified hyaluronic acid and tannic acid. The phenylboronic acid ester in 3EVs-Dxm-Gel enabled effective immobilization and reactive oxygen species-responsive release of EVs. Topical injection of 3EVs-Dxm-Gel in SCI rats notably mitigated injury severity and promoted functional recovery, which may offer opportunities for EV-based therapeutics in central nervous system injury.

Multi-targeted nanogel drug delivery system alleviates neuroinflammation and promotes spinal cord injury repair

Spinal cord injury (SCI) is significantly hampered by an inflammatory microenvironment, prompting continued efforts in drug development to address inflammation. Research shows that quercetin (Que) exhibits excellent performance in reducing inflammation and neuroprotection. However, its application is limited by poor solubility, notable side effects, and the unique pathophysiology of the spinal cord. In this study, we introduce a novel multifunctional liposome hydrogel drug delivery system (QLipTC@HDM), obtained by incorporating liposomes with blood-spinal cord barrier penetration and injury site targeting properties (LipTC) into a dual-network viscous hydrogel (HDM). Our results demonstrate that encapsulating Que in LipTC (QLipTC) enhances solubility, minimizes toxic side effects, facilitates lesion targeting, and aids in crossing the blood-spinal cord barrier. Moreover, encapsulation in HDM significantly prolongs the retention of QLipTC at the injury site after local administration. Crucially, our findings reveal that QLipTC@HDM induces M2 phenotype transformation in glial cells and in mice with SCI, thereby mitigating inflammation. This intervention additionally preserves the integrity of the blood-spinal cord barrier, optimizes the spinal cord microenvironment, reduces glial scarring, promotes axonal regeneration, and enhances motor function recovery in SCI mice. In summary, our investigations highlight the potential of this disease-specific drug delivery system as a promising therapeutic approach for the treatment and management of SCI.

Centripetal migration and prolonged retention of microglia promotes spinal cord injury repair

BACKGROUND

Recent studies have confirmed the critical role of neonatal microglia in wound healing and axonal regeneration following spinal cord injury (SCI). However, the limited migration of microglia to the center of adult lesion may significantly impede their potential benefits.

METHODS

We established a model of microglial centripetal migration and prolonged retention in C57BL/6J and transgenic mice by injecting exogenous C-X3-C motif chemokine ligand 1 (CX3CL1) and macrophage colony-stimulating factor (M-CSF) directly into the lesion site post-SCI. Wound healing and axonal preservation/regrowth was assessed anatomically, and kinematics analysis was conducted to determine the recovery of locomotor function.

RESULTS

We identified decreased expression and perilesional distribution of CX3CL1 as the primary reason for the limited centripetal migration of microglia. In situ injection of CX3CL1 into the lesion core promoted microglial centripetal migration, but alone did not improve functional recovery. Nevertheless, a combinational administration of CX3CL1 and M-CSF fostered both centripetal migration and prolonged retention of microglia, thereby effectively displacing blood-derived macrophage infiltration and optimizing wound healing and axonal preservation/regrowth after SCI. Notably, the beneficial effects of CX3CL1 and M-CSF co-administration were specifically blocked in C-X3-C motif chemokine receptor 1 (CX3CR1)-deficient mice. These phenomena may be related to the increase in spleen tyrosine kinase (SYK) levels, which boosts centripetal microglial phagocytosis.

CONCLUSION

Our study uncovers the criticality of microglial location and abundance in orchestrating SCI repair, highlighting centripetal microglial dynamics as valuable targets for therapeutic intervention.

Quercetin-Loaded Nanoparticle-Modified Decellularized Tissue-Engineered Vascular Graft Regulates Macrophage Polarization and Promotes In Vivo Graft Remodeling

Introduction

Arteriovenous graft (AVG) is an important option for establishing hemodialysis access in patients with end-stage chronic kidney disease (CKD). Decellularized tissue-engineered vascular graft (dTEVG), due to its excellent biocompatibility and regenerative potential, holds promise for use in AVG; however, poor remodeling remains a challenge. Quercetin (Qu) can effectively regulate macrophage polarization and promote tissue remodeling and regeneration, yet its low bioavailability limits its clinical application.

Methods

Here, we developed a nano-localized drug delivery system using Qu-loaded poly(lactic-co-glycolic acid) (PLGA) nanoparticles (Qu@PNPs), prepared via a nanoprecipitation method and subsequently modified onto the surface of dTEVG. In vitro and in vivo experiments were performed to assess the biocompatibility of Qu@PNPs and their effect on macrophage polarization. Additionally, the impact of Qu@PNPs modification on dTEVG remodeling was evaluated in both subcutaneous and AVG rat models.

Results

Our study results demonstrated that Qu@PNPs exhibited good biocompatibility and achieved sustained drug release on dTEVG. Furthermore, these drug-loaded nanoparticles inhibited M1 macrophage polarization while promoting M2 polarization, significantly improving the in vivo remodeling of dTEVG, as evidenced by increased early recellularization and peripheral neovascularization.

Conclusion

Together, the development of the nano-localized drug delivery system effectively enhanced the application of Qu, providing experimental evidence for its use in dTEVG. Additionally, it offers new strategies and approaches for optimizing dTEVG design and clinical translation.

IL-4-primed human umbilical cord mesenchymal stem cells-derived extracellular vesicles facilitate recovery in spinal cord injury via the miR-21-5p/PDCD4-mediated shifting of macrophage M1/M2 polarization

Spinal cord injury (SCI) represents a significant neurological disorder that profoundly impacts human life. Transplantation of extracellular vesicles (EVs) from human umbilical cord mesenchymal stem cells (hUC-MSCs) has emerged as a promising therapeutic strategy. microRNA (miRNA) containing EVs serve as crucial mediators of intercellular communication, playing vital roles in physiological and pathological processes. Research indicates that EVs from hUC-MSCs could attenuate inflammation and facilitate recovery from SCI. Nevertheless, their application in clinical treatment necessitates further investigation. We are actively pursuing an effective approach to modulate the intensity of the inflammatory response, thereby addressing secondary SCI. Initially, we activated hUC-MSCs with interleukin-4 (IL-4) and subsequently harvested their EVs. We investigated the influences of A-hUC-MSCs-EVs compared to routinely acquired EVs on macrophage polarization phenotypes both in vitro and in vivo. Our results show that EVs originating from A-hUC-MSCs are more effective at promoting macrophage polarization from the M1 phenotype to the M2 phenotype than those derived from hUC-MSCs. Notably, we found that A-hUC-MSCs-derived EVs had a superior impact on motor function recovery in mice with SCI. Importantly, we observed that IL-4 activation significantly upregulated the expression of miR-21-5p within these EVs. More specifically, our data demonstrate that A-hUC-MSCs-EVs depend on miR-21-5p to inhibit the effects of PDCD4 on macrophage polarization. This mechanism regulates inflammatory responses while simultaneously reducing apoptosis. In summary, EVs derived from IL-4 primed hUC-MSCs are enriched with miR-21-5p, which exerts a pivotal influence in shifting macrophage polarization, alleviating inflammatory responses following SCI, and facilitating recovery.

Therapeutic potential of flavonoids in neuroprotection: brain and spinal cord injury focus

Flavonoids in fruits, vegetables, and plant-based drinks have potential neuroprotective properties, with clinical research focusing on their role in reducing oxidative stress, controlling inflammation, and preventing apoptosis. Some flavonoids, such as quercetin, kaempferol, fisetin, apigenin, luteolin, chrysin, baicalein, catechin, epigallocatechin gallate, naringenin, naringin, hesperetin, genistein, rutin, silymarin, and daidzein, have been presented to help heal damage to the central nervous system by affecting key signaling pathways including PI3K/Akt and NF-κB. This review systematically analyzed articles on flavonoids, neuroprotection, and brain and spinal cord injury from primary medical databases like Scopus, PubMed, and Web of Science. Flavonoids enhance antioxidant defenses, reduce pro-inflammatory cytokine production, and aid cell survival and repair by focusing on specific molecular pathways. Clinical trials are also exploring the application of preclinical results to therapeutic approaches for patients with spinal cord injury and traumatic brain injury. Flavonoids can enhance injury healing, reduce lesion size, and enhance synaptic plasticity and neurogenesis. The full potential of flavonoids lies in their bioavailability, dose, and administration methods, but there are still challenges to overcome. This review explores flavonoid-induced neuroprotection, its clinical implications, future research opportunities, and molecular mechanisms, highlighting the potential for innovative CNS injury therapies and improved patient health outcomes.

Quercetin alleviates neonatal hypoxic-ischaemic brain injury by rebalancing microglial M1/M2 polarization through silent information regulator 1/ high mobility group box-1 signalling

Neonatal hypoxic-ischaemic encephalopathy (HIE) remains one of the major causes of neonatal death and long-term neurological disability. Due to its complex pathogenesis, there are still many challenges in its treatment. In our previous studies, we found that quercetin can alleviate neurological dysfunction after hypoxic-ischaemic brain injury (HIBI) in neonatal mice. As demonstrated through in vitro experiments, quercetin can inhibit the activation of the TLR4/MyD88/NF-κB signalling pathway and the inflammatory response in the microglial cell line BV2 after oxygen-glucose deprivation. However, the in-depth mechanism still needs to be further elucidated. In the present study, 7 day-old neonatal ICR mice or BV2 cells were treated with quercetin with or without the SIRT1 inhibitor EX527 via neurobehavioural, histopathological and molecular methods. In vivo experiments have shown that quercetin can significantly improve the performance of HI mice in behavioural tests, such as the Morris water maze, rotarod test and pole climbing test, and reduce HI insult-induced structural brain damage, cell apoptosis and hippocampal neuron loss. Quercetin also inhibited the immunofluorescence intensity of the microglial M1 marker CD16 + 32 and significantly downregulated the expression of the M1-related proteins iNOS, IL-1β and TNF-α. Moreover, quercetin increased the immunofluorescence intensity of the microglial M2 marker CD206 and significantly increased the expression of the M2-related proteins Arg-1 and IL-10. In addition, quercetin limits the nucleocytoplasmic translocation and release of microglial HMGB1 and further suppresses the activation of the downstream TLR4/MyD88/NF-κB signalling pathway. The above effects of quercetin are partially weakened by pretreatment with EX527. Similar results were found in in vitro experiments, and the mechanism further revealed that the rebalancing effect of quercetin on microglial polarization is achieved through the SIRT1-mediated reduction in HMGB1 acetylation levels. This study provides new and complementary insights into the neuroprotective effects of quercetin and a new direction for the treatment of neonatal HIE.

Water-soluble sulfur quantum dots as a potential sensitive fluorescent probe for quercetin detection and cell imaging

A simple fluorescent quenching probe based on polyethylene glycol-400 capped sulfur quantum dots (PEG-SQDs) was fabricated to determine quercetin (QT) quantitatively. As anticipated, the PEG-SQDs exhibited favourable luminescent properties, stability and low cytotoxicity. QT effectively quenched the fluorescence of the PEG-SQDs through static quenching and the inner filter effect. Moreover, the PEG-SQDs showed rapid QT detection within a linear range of 0.100-45.0 μM, with a limit of detection of 0.014 μM (3σ/k). This fluorescent probe successfully detected QT in human serum, quercetin supplement capsules and red wine, achieving a standard recovery of 92.6 %-105 %.

Effects of Quercetin against fluoride-induced neurotoxicity in the medial prefrontal cortex of rats: A stereological, histochemical and behavioral study

BACKGROUND

Exposure to high levels of fluoride leads to brain developmental and functional damage. Motor performance deficits, learning and memory dysfunctions are related to fluoride neurotoxicity in human and rodent studies.

MATERIALS AND METHODS

Here, we evaluated the effects of Quercetin treatment (25 mg/kg) against sodium fluoride-induced neurotoxicity (NaF, 200 ppm) in the medial prefrontal cortex (mPFC) of male adult rats based on oxidative markers, behavioral performances, mRNA expressions, and stereological parameters. After a 4-week experimental period, the brains of rats were collected and used for molecular and histological analysis.

RESULTS

We found that 4 weeks of NaF exposure decreased body weight, working memory, Brain-derived neurotrophic factor (BDNF) mRNA expression, total volume of mPFC, number of neurons and non-neuronal cells in the mPFC, and anti-oxidative markers (CAT, SOD, and GSH-Px), while increased lipid peroxidation, P53 mRNA expression and anxiety. Quercetin treatment could significantly reverse the neurotoxic effect of NaF in the mPFC.

CONCLUSIONS

In summary, Quercetin could decrease the detrimental effects of NaF in the mPFC of adult rats by improving antioxidant potency and consequently decreasing neuronal and non-neuronal apoptosis.

SIX1 aggravates the progression of spinal cord injury in mice by promoting M1 polarization of microglia

Inflammation aggravates secondary damage following spinal cord injury (SCI). M1 microglia induce inflammation and exert neurotoxic effects, whereas M2 microglia exert anti-inflammatory and neuroprotective effects. The sine oculis homeobox (SIX) gene family consists of six members, including sine oculis homeobox homolog 1 (SIX1)-SIX6. SIX1 is expressed in microglia and promotes inflammation. This study aimed to evaluate the role and underlying mechanisms of SIX1 in microglia polarization in vitro (LPS-treated mouse microglia; BV2 cells) and in vivo (a mouse model of SCI). SIX1 expression was increased in the microglia of mice with SCI. SIX1 was positively correlated with the M1 microglia marker inducible nitric oxide synthase (iNOS) and negatively correlated with the M2 microglia marker arginase 1 (Arg1) in mice with SCI. Knockdown of SIX1 promoted functional recovery by enhancing M2 microglia polarization in mice with SCI. The transcription, expression, and activity of enhancer of zeste homolog 2 (EZH2) were decreased in LPS-stimulated BV2 cells. Downregulation of EZH2 promoted SIX1 expression in LPS-treated BV2 cells by inhibiting the methylation of the SIX1 promoter. SIX1 enhanced the transcription of vascular endothelial growth factor-C (VEGF-C) in LPS-stimulated BV2 cells with downregulated EZH2. VEGF-C promoted M1 polarization and inhibited M2 polarization in BV2 cells by binding to vascular endothelial growth factor receptor 3 (VEGFR3). Overall, the results suggest that SIX1 promotes M1 polarization of microglia following SCI by upregulating the VEGF-C/VEGFR3 axis, whereas the blockade of SIX1 can improve the recovery of locomotor function following SCI, demonstrating a novel strategy for the treatment of SCI.

ROS-mediated M1 polarization-necroptosis crosstalk involved in Di-(2-ethylhexyl) phthalate-induced chicken liver injury

The widespread use of plasticizers poses a serious threat to the environment and poultry health. Di-(2-ethylhexyl) phthalate (DEHP) is a commonly used plasticizer that can cause liver damage with prolonged exposure. Oxidative stress is closely associated with DEHP toxicity. Macrophage polarization plays an important role in many physiological and pathological processes and regulates disease development. This study aims to elucidate the mechanism of chronic DEHP exposure leading to chicken liver injury through oxidative stress-induced M1 polarization-necroptosis. In this study, the DEHP exposure model of chicken liver and the single and co-culture model of LMH and HD11 cells were established. With increasing dose and time, DEHP decreased body weight, increased liver coefficient, raised activities of liver function indicators and caused pathological liver damage in chickens. Further studies revealed the increase of reactive oxygen species (ROS) level and malonaldehyde (MDA) content, and the decrease of total antioxidant capacity (T-AOC) level, total superoxide dismutase (T-SOD) and glutathione peroxidase (GSH-Px) activities, which led to excessive oxidative stress in the liver. In addition, there was increased infiltration of liver macrophages (CD68), upregulation of M1 polarization indicators (CD86, iNOS, IL-1β, TNF-α) and downregulation of M2 polarization indicators (CD163, Arg-1, IL-10, TGF-β) and appearance of necroptosis (RIPK1, RIPK3, MLKL). The vitro experiments confirmed the addition of N-acetylcysteine (NAC) inhibited M1 polarization and necroptosis. Besides, M1 polarization of HD11 cells promoted necroptosis of LMH cells in the HD11-LMH co-culture system. In brief, ROS-mediated M1 polarization-necroptosis is involved in DEHP-induced liver injury. This study provides a reference for environmental toxicant exposure in livestock and poultry farming.

Ingenane diterpenoids with anti-inflammatory activity from Euphorbia antiquorum

The Euphorbia plants are famous for their diterpenoid constituents with diverse structures and broad biological activities. Herein, the discovery of 15 ingenane diterpenoids including 10 previously unreported ones (1-10) from Euphorbia antiquorum was presented. Structures of the undescribed compounds were established via detailed spectroscopic analyses. Meanwhile, a preliminary anti-inflammatory screening revealed that compound 6 showed significant inhibitory activity against the production of nitric oxide, as well as downregulated the expression of COX-2 and IL-6, in lipopolysaccharide-stimulated RAW264.7 macrophages. Further mechanistical exploration revealed that compound 6 could exert its anti-inflammatory effect by inhibiting NF-κB and activating Nrf2 signaling pathways.

Regulation of nerve cells and therapeutic potential in central nervous system injury using microglia-derived exosomes

The intercellular communication within the central nervous system (CNS) is of great importance for in maintaining brain function, homeostasis, and CNS regulation. When the equilibrium of CNS is disrupted or injured, microglia are immediately activated and respond to CNS injury. Microglia-derived exosomes are capable of participating in intercellular communication within the CNS by transporting various bioactive substances, including nucleic acids, proteins, lipids, amino acids, and metabolites. Nevertheless, microglia activation is a double-edged sword. Activated microglia can coordinate the neural repair process and, conversely, can amplify tissue injury and impede CNS repair. This work reviewed the roles of exosomes derived from microglia stimulated by different environments (mainly lipopolysaccharide, interleukin-4, and other specific preconditioning) in CNS injury and their possible therapeutic potentials. This work focuses on the regulation of exosomes derived from microglia stimulated by different environments on nerve cells. Meanwhile, we summarized the molecular mechanisms by which the relevant exosomes exert regulatory effects. Exosomes, derived from microglia stimulated by different environments, regulate other nerve cells during the repair of CNS injury, having beneficial or detrimental effects on CNS repair. A comprehensive understanding of the molecular mechanisms underlying their role can provide a robust foundation for the clinical treatment of CNS injury.

Extract from Nasco pomace loaded in nutriosomes exerts anti-inflammatory effects in the MPTP mouse model of Parkinson's disease

Neuroinflammation has recently emerged as a key event in Parkinson's disease (PD) pathophysiology and as a potential target for disease-modifying therapies. Plant-derived extracts, rich in bioactive phytochemicals with antioxidant properties, have shown potential in this regard. Yet their clinical utility is hampered by poor systemic availability and rapid metabolism. Recently, our group demonstrated that intragastric delivery of Nasco pomace extract via nutriosomes (NN), a novel nanoliposome formulation, contrasts the degeneration of nigrostriatal dopaminergic neurons in a subacute 1-methyl-4-phenyl-1,2,3,6-tetrahydropyridine (MPTP) mouse model of PD. In the present study, we investigated the impact of intragastric NN treatment on the reactivity of glial cells in the substantia nigra pars compacta (SNc) and caudate-putamen (CPu) of MPTP-treated mice. To this scope, in mice exposed to MPTP (20 mg/kg/day, × 4 days), we conducted immunohistochemistry analyses of glial fibrillary acidic protein (GFAP) and ionized calcium-binding adapter molecule 1 (IBA1) to assess the responsiveness of astrocytes and microglial cells, respectively. Additionally, we studied the co-localization of the pro-inflammatory interleukin (IL)-1β and tumor necrosis factor (TNF)-α with IBA1 to obtain insights into microglial phenotype. Immunohistochemical results showed that NN administration significantly mitigated astrogliosis and microgliosis in the CPu and SNc of mice receiving subacute MPTP treatment, with region-specific variations in anti-inflammatory efficacy. Remarkably, the CPu showed a heightened response to NN treatment, including a pronounced decrease in microglial IL-1β and TNF-α production. Altogether, these findings underscore the anti-inflammatory effects of NN treatment and provide a potential mechanism underlying the neuroprotective effects previously observed in a subacute MPTP mouse model of PD.

Therapeutic implication of targeting mitochondrial drugs designed for efferocytosis dysfunction

Efferocytosis refers to the process by which phagocytes remove apoptotic cells and related apoptotic products. It is essential for the growth and development of the body, the repair of damaged or inflamed tissues, and the balance of the immune system. Damaged efferocytosis will cause a variety of chronic inflammation and immune system diseases. Many studies show that efferocytosis is a process mediated by mitochondria. Mitochondrial metabolism, mitochondrial dynamics, and communication between mitochondria and other organelles can all affect phagocytes' clearance of apoptotic cells. Therefore, targeting mitochondria to modulate phagocyte efferocytosis is an anticipated strategy to prevent and treat chronic inflammatory diseases and autoimmune diseases. In this review, we introduced the mechanism of efferocytosis and the pivoted role of mitochondria in efferocytosis. In addition, we focused on the therapeutic implication of drugs targeting mitochondria in diseases related to efferocytosis dysfunction.

Pharmacological Network Analysis of the Functions and Mechanism of Quercetin From Jisuikang (JSK) in Spinal Cord Injury (SCI)

Neuroinflammation, especially microglia/macrophage activation, is a hallmark of spinal cord injury (SCI). Jisuikang (JSK) is a clinical experiential Chinese herbal formula for SCI therapy containing Huangqi (Astragali Radix), Danggui (Angelica sinensis Radix), Chishao (Paeoniae Radix Rubra), Dilong (earthworm, Pheretima aspergillum), Chuanxiong (Chuanxiong Rhizoma), Taoren (Persicae Seman) and Honghua (Carthami Flos). Eighteen active ingredients in 6 herbs of JSK were found to be correlated with inflammation, spinal injury and other diseases. These 18 active ingredients target 5464 genes according to the PubChem database. Through comparing differentially expressed genes between SCI and normal samples using GSE datasets, 50 hub genes were identified. These hub-genes were enriched in oxidative stress response and inflammation response. The herb-compound-target, herb-compound-signalling and compound-target-signalling networks were generated and quercetin was identified as the hub compound. A concentration of 25 μM quercetin showed no cytotoxicity but significantly protected microglial cells from LPS-induced inhibition of cell viability. LPS stimulation elevated the levels of iNOS, IL-1β and TNF-α but decreased IL-10 levels, whereas quercetin significantly attenuated LPS-induced alterations in these factors. Moreover, quercetin targeted gene, IL1R1 was reduced by quercetin as predicted. Overexpression of IL1R1 further increased LPS-induced inflammation, which could be partly reversed by quercetin treatment. In vivo, quercetin improved histopathological alterations, inflammation and promoted M2 macrophage polarisation post-injury, whereas IL1R1 overexpression partially attenuated the beneficial effects of quercetin on the rat SCI model. Collectively, quercetin, the main ingredient compound of JSK, protects against LPS-induced cell viability inhibition and cellular inflammation, which could be partially attenuated by IL1R1 overexpression.

Crosstalk Between Cell Death and Spinal Cord Injury: Neurology and Therapy

Spinal cord injury (SCI) often leads to neurological dysfunction, and neuronal cell death is one of the main causes of neurological dysfunction. After SCI, in addition to necrosis, programmed cell death (PCD) occurs in nerve cells. At first, studies recognized only necrosis, apoptosis, and autophagy. In recent years, researchers have identified new forms of PCD, including pyroptosis, necroptosis, ferroptosis, and cuproptosis. Related studies have confirmed that all of these cell death modes are involved in various phases of SCI and affect the direction of the disease through different mechanisms and pathways. Furthermore, regulating neuronal cell death after SCI through various means has been proven to be beneficial for the recovery of neural function. In recent years, emerging therapies for SCI have also provided new potential methods to restore neural function. Thus, the relationship between SCI and cell death plays an important role in the occurrence and development of SCI. This review summarizes and generalizes the relevant research results on neuronal necrosis, apoptosis, autophagy, pyroptosis, necroptosis, ferroptosis, and cuproptosis after SCI to provide a new understanding of neuronal cell death after SCI and to aid in the treatment of SCI.

Promoting remyelination in central nervous system diseases: Potentials and prospects of natural products and herbal medicine

Myelin damage is frequently associated with central nervous system (CNS) diseases and is a critical factor influencing neurological function and disease prognosis. Nevertheless, the majority of current treatments for the CNS concentrate on gray matter injury and repair strategies, while clinical interventions specifically targeting myelin repair remain unavailable. In recent years, natural products and herbal medicine have achieved considerable progress in the domain of myelin repair, given their remarkable curative effect and low toxic side effects, demonstrating significant therapeutic potential. In this review, we present a rather comprehensive account of the mechanisms underlying myelin formation, injury, and repair, with a particular emphasis on the interactions between oligodendrocytes and other glial cells. Furthermore, we summarize the natural products and herbal medicine currently employed in remyelination along with their mechanisms of action, highlighting the potential and challenges of certain natural compounds to enhance myelin repair. This review aims to facilitate the expedited development of innovative therapeutics derived from natural products and herbal medicine and furnish novel insights into myelin repair in the CNS.

scRNA-Seq reveals age-dependent microglial evolution as a determinant of immune response following spinal cord injury

Spinal cord injury (SCI) is a debilitating condition of the central nervous system (CNS) that leads to severe impairments in sensory and motor functions. Previous studies have pointed out that patient age is a critical factor influencing SCI prognosis. However, the role of microglia in age-related differences in SCI outcomes remains unclear. The current study aims to identify specific microglial subtypes and investigate their responses and functional differences in SCI recovery across different age groups. Single-cell RNA sequencing (scRNA-seq) data were obtained from the Gene Expression Omnibus (GEO) database, integrating multiple datasets to identify microglial subtypes. We performed pseudotime trajectory analysis and cell-cell communication analysis to understand microglial differentiation and interactions. Finally, immunofluorescence staining of mouse model samples was conducted to validate our bioinformatics findings. Microglia were classified into four subtypes: Homeostatic, Proliferating, Inflammatory A, and Inflammatory B. The Young SCI group exhibited a higher proportion of Homeostatic microglia and Inflammatory microglia A, whereas the old SCI group had more Inflammatory Microglia B but lacked Homeostatic Microglia. Gene ontology (GO) and Kyoto Encyclopedia of Genes and Genomes (KEGG) pathway analyses revealed that markers for homeostasis microglia were enriched in immune modulation pathways. While makers for Inflammatory Microglia were enriched in immune response pathways. Specifically, markers for Inflammatory microglia B were enriched in pathways associated with overactive immune response. Pseudotime analysis indicated that microglia in young mice predominantly differentiated into Inflammatory Microglia A and Homeostatic Microglia, whereas in old mice, they tended to only differentiate into Inflammatory Microglia B. CellChat analysis showed increased pro-inflammatory signaling generated by Inflammatory Microglia B, exclusively in the old group. Our study demonstrates significant differences in microglial subtypes and functions between different age groups following SCI. These findings provide novel insights into the development of age-related therapeutic strategies and microglia-targeted biological treatments for SCI.

Compound 7 regulates microglia polarization and attenuates radiation-induced myelopathy via the Nrf2 signaling pathway in vivo and in vitro studies

BACKGROUND

Radiation-induced myelopathy (RM) is a significant complication of radiotherapy with its mechanisms still not fully understood and lacking effective treatments. Compound 7 (C7) is a newly identified, potent, and selective inhibitor of the Keap1-Nrf2 interaction. This study aimed to explore the protective effects and mechanisms of C7 on RM in vitro and in vivo.

METHODS

Western blotting, quantitative real-time polymerase chain reaction (qRT-PCR), reactive oxygen species (ROS) and mitochondrial polarization, terminal deoxynucleotidyl transferase dUTP nick end labeling (TUNEL) assay, genetic editing techniques, locomotor functions, and tissue staining were employed to explore the protective effects and underlying mechanisms of C7 in radiation-induced primary rat microglia and BV2 cells, as well as RM rat models.

RESULTS

In this study, we found that C7 inhibited the production of pro-inflammation cytokines and oxidative stress induced by irradiation in vitro. Further, the data revealed that radiation worsened the locomotor functions in rats, and C7 significantly improved histological and functional recovery in RM rats. Mechanically, C7 activated Nrf2 signaling and promoted the microglia transformation from M1 to M2 phenotype.

CONCLUSION

C7 could ameliorate RM by boosting Nrf2 signaling and promoting M2 phenotype microglia polarization in vitro and in vivo.

Identification of Anoikis-Related Genes in Spinal Cord Injury: Bioinformatics and Experimental Validation

Spinal cord injury (SCI) is a serious disease without effective therapeutic strategies. To identify the potential treatments for SCI, it is extremely important to explore the underlying mechanism. Current studies demonstrate that anoikis might play an important role in SCI. In this study, we aimed to identify the key anoikis-related genes (ARGs) providing therapeutic targets for SCI. The mRNA expression matrix of GSE45006 was downloaded from the Gene Expression Omnibus (GEO) database, and the ARGs were downloaded from the Molecular Signatures Database (MSigDB database). Then, the potential differentially expressed ARGs were identified. Next, correlation analysis, gene ontology (GO) enrichment analysis and Kyoto Encyclopedia of Genes and Genomes (KEGG) pathway enrichment analysis, and protein-protein interaction (PPI) analysis were employed for the differentially expressed ARGs. Moreover, miRNA-gene networks were constructed by the hub ARGs. Finally, RNA expression of the top ten hub ARGs was validated in the SCI cell model and rat SCI model. A total of 27 common differentially expressed ARGs were identified at different time points (1, 3, 7, and 14 days) following SCI. The GO and KEGG enrichment analysis of these ARGs indicated several enriched terms related to proliferation, cell cycle, and apoptotic process. The PPI results revealed that most of the ARGs interacted with each other. Ten hub ARGs were further screened, and all the 10 genes were validated in the SCI cell model. In the rat model, only seven genes were validated eventually. We identified 27 differentially expressed ARGs of the SCI through bioinformatic analysis. Seven real hub ARGs (CCND1, FN1, IGF1, MYC, STAT3, TGFB1, and TP53) were identified eventually. These results may expand our understanding of SCI and contribute to the exploration of potential SCI targets.

Regulation of microglia inflammation and oligodendrocyte demyelination by Engeletin via the TLR4/RRP9/NF-κB pathway after spinal cord injury

Microglia polarization is crucial for neuroinflammatory response after spinal cord injury (SCI). Small molecule compounds and hub genes play an important role in regulating microglia polarization, reducing neuroinflammatory response and oligodendrocyte demyelination after SCI. In this study, suitable data sets were used to screen hub genes, and Western blot and Immunofluorescence (IF) experiments were used to confirm the expressions of proteins related to SDAD1, RRP9 and NF-κB pathways under LPS/SCI conditions. Engeletin (ENG) reduced microglia polarization and inflammation in vivo and in vitro via the SDAD1, RRP9 or NF-κB signaling pathways. In addition, ENG binds to the membrane receptor Toll-like receptor 4 (TLR4) through small molecule-protein docking. COIP experiment and protein-protein docking revealed protein-protein interaction (PPI) between RRP9 and SDAD1. By gene knock-down (KD) / overexpression (OE) and Western blot experiments, RRP9 and SDAD1 can regulate inflammatory response through NF-κB signaling and ribosome biogenesis pathway. Western blot analysis showed that CU increased the expression of SDAD1, RRP9 and NF-κB pathway related proteins through TLR1/2, while C34 decreased the expression of SDAD1 and RRP9 proteins through TLR4. These results suggest that ENG can reduce inflammation through TLR4/RRP9(SDAD1)/NF-κB signaling pathway. In addition, we demonstrated that oligodendrocyte apoptosis and demyelination could be influenced by the regulation of microglia and tissue inflammation. In conclusion, this study found the gene Rrp9/Sdad1 and the small molecule compound ENG, which control the inflammatory response of microglia, and further explored the related mechanism of oligodendrocyte demyelination, which has important theoretical significance.

Gelatin Methacrylic Acid Hydrogel-Based Nerve Growth Factors Enhances Neural Stem Cell Growth and Differentiation to Promote Repair of Spinal Cord Injury

Background

The challenge in treating irreversible nerve tissue damage has resulted in suboptimal outcomes for spinal cord injuries (SCI), underscoring the critical need for innovative treatment strategies to offer hope to patients.

Methods

In this study, gelatin methacrylic acid hydrogel scaffolds loaded with nerve growth factors (GMNF) were prepared and used to verify the performance of SCI. The physicochemical and biological properties of the GMNF were tested. The effect of GMNF on activity of neuronal progenitor cells (NPCs) was investigated in vitro. Histological staining and motor ability was carried out to assess the ability of SCI repair in SCI animal models.

Results

Achieving nerve growth factors sustained release, GMNF had good biocompatibility and could effectively penetrate into the cells with good targeting permeability. GMNF could better enhance the activity of NPCs and promote their directional differentiation into mature neuronal cells in vitro, which could exert a good neural repair function. In vivo, SCI mice treated with GMNF recovered their motor abilities more effectively and showed better wound healing by macroscopic observation of the coronal surface of their SCI area. Meanwhile, the immunohistochemistry demonstrated that the GMNF scaffolds effectively promoted SCI repair by better promoting the colonization and proliferation of neural stem cells (NSCs) in the SCI region and targeted differentiation into mature neurons.

Conclusion

The application of GMNF composite scaffolds shows great potential in SCI treatment, which are anticipated to be a potential therapeutic bioactive material for clinical application in repairing SCI in the future.

The dual role of microglia in intracerebral hemorrhage

Intracerebral hemorrhage has the characteristics of high morbidity, disability and mortality, which has caused a heavy burden to families and society. Microglia are resident immune cells in the central nervous system, and their activation plays a dual role in tissue damage after intracerebral hemorrhage. The damage in cerebral hemorrhage is embodied in the following aspects: releasing inflammatory factors and inflammatory mediators, triggering programmed cell death, producing glutamate induced excitotoxicity, and destroying blood-brain barrier; The protective effect is reflected in the phagocytosis and clearance of harmful substances by microglia, and the secretion of anti-inflammatory and neurotrophic factors. This article summarizes the function of microglia and its dual regulatory mechanism in intracerebral hemorrhage. In the future, drugs, acupuncture and other clinical treatments can be used to intervene in the activation state of microglia, so as to reduce the harm of microglia.

Sonic Hedgehog reduces inflammatory response, decreases blood-spinal cord barrier permeability, and improves locomotor function recovery in an acute spinal cord injury rat model

BACKGROUND

Sonic Hedgehog (Shh), extensively researched for its role in early neurogenesis and brain development, has recently been recognized for its neuroprotective potential following neuronal injuries. This study examines the immediate impact of early administered Shh on the local inflammatory response post-acute spinal cord injury in rats.

METHODS

Thirty-four female Wistar rats underwent either sham surgery (laminectomy; n = 10) or clip compression/contusion spinal cord injury (SCI) at the T9 level. This was followed by implantation of an osmotic pump and a subdural catheter for continuous intrathecal delivery of Shh (n = 12) or placebo (NaCl; n = 12). Locomotor function was assessed at 3- and 7-days post-injury (dpi) using the Basso, Beattie, and Bresnahan (BBB) score and the Gridwalk test. Animals were euthanized after 3 or 7 days for immunohistochemical analysis of the local inflammatory reaction and immune cell migration.

RESULTS

Shh-treated rats demonstrated significant hindlimb movement and coordination improvements at 7 days post-injury, compared to controls. This enhancement was accompanied by a significant reduction in both immune cell presence and blood plasma products within spinal cord lesions, suggesting Shh's dual role in modulating immune cell migration and maintaining the integrity of the blood-spinal cord barrier. Separately, these Shh-treated rats also showed an increase in M(IL-4) polarization of macrophages, further underlining the potential therapeutic impact of Shh in post-injury recovery. Notably, these effects were not evident at three days post-injury.

CONCLUSION

Shh application at 7 days post-injury showed immunomodulatory effects, possibly via enhanced blood-spinal cord barrier integrity, reduced immune cell migration, and increased anti-inflammatory immune cell differentiation. These mechanisms collectively contribute to enhanced locomotor recovery.

The iron maiden: Oligodendroglial metabolic dysfunction in multiple sclerosis and mitochondrial signaling

Multiple sclerosis (MS) is an autoimmune disease, governed by oligodendrocyte (OL) dystrophy and central nervous system (CNS) demyelination manifesting variable neurological impairments. Mitochondrial mechanisms may drive myelin biogenesis maintaining the axo-glial unit according to dynamic requisite demands imposed by the axons they ensheath. The promotion of OL maturation and myelination by actively transporting thyroid hormone (TH) into the CNS and thereby facilitating key transcriptional and metabolic pathways that regulate myelin biogenesis is fundamental to sustain the profound energy demands at each axo-glial interface. Deficits in regulatory functions exerted through TH for these physiological roles to be orchestrated by mature OLs, can occur in genetic and acquired myelin disorders, whereby mitochondrial efficiency and eventual dysfunction can lead to profound oligodendrocytopathy, demyelination and neurodegenerative sequelae. TH-dependent transcriptional and metabolic pathways can be dysregulated during acute and chronic MS lesion activity depriving OLs from critical acetyl-CoA biochemical mechanisms governing myelin lipid biosynthesis and at the same time altering the generation of iron metabolism that may drive ferroptotic mechanisms, leading to advancing neurodegeneration.

Biochanin A attenuates spinal cord injury in rats during early stages by inhibiting oxidative stress and inflammasome activation

JOURNAL/nrgr/04.03/01300535-202409000-00038/figure1/v/2024-01-16T170235Z/r/image-tiff Previous studies have shown that Biochanin A, a flavonoid compound with estrogenic effects, can serve as a neuroprotective agent in the context of cerebral ischemia/reperfusion injury; however, its effect on spinal cord injury is still unclear. In this study, a rat model of spinal cord injury was established using the heavy object impact method, and the rats were then treated with Biochanin A (40 mg/kg) via intraperitoneal injection for 14 consecutive days. The results showed that Biochanin A effectively alleviated spinal cord neuronal injury and spinal cord tissue injury, reduced inflammation and oxidative stress in spinal cord neurons, and reduced apoptosis and pyroptosis. In addition, Biochanin A inhibited the expression of inflammasome-related proteins (ASC, NLRP3, and GSDMD) and the Toll-like receptor 4/nuclear factor-κB pathway, activated the Nrf2/heme oxygenase 1 signaling pathway, and increased the expression of the autophagy markers LC3 II, Beclin-1, and P62. Moreover, the therapeutic effects of Biochanin A on early post-spinal cord injury were similar to those of methylprednisolone. These findings suggest that Biochanin A protected neurons in the injured spinal cord through the Toll-like receptor 4/nuclear factor κB and Nrf2/heme oxygenase 1 signaling pathways. These findings suggest that Biochanin A can alleviate post-spinal cord injury at an early stage.

Macrophage GIT1 promotes oligodendrocyte precursor cell differentiation and remyelination after spinal cord injury

Spinal cord injury (SCI) can result in severe motor and sensory deficits, for which currently no effective cure exists. The pathological process underlying this injury is extremely complex and involves many cell types in the central nervous system. In this study, we have uncovered a novel function for macrophage G protein-coupled receptor kinase-interactor 1 (GIT1) in promoting remyelination and functional repair after SCI. Using GIT1flox/flox Lyz2-Cre (GIT1 CKO) mice, we identified that GIT1 deficiency in macrophages led to an increased generation of tumor necrosis factor-alpha (TNFα), reduced proportion of mature oligodendrocytes (mOLs), impaired remyelination, and compromised functional recovery in vivo. These effects in GIT1 CKO mice were reversed with the administration of soluble TNF inhibitor. Moreover, bone marrow transplantation from GIT1 CWT mice reversed adverse outcomes in GIT1 CKO mice, further indicating the role of macrophage GIT1 in modulating spinal cord injury repair. Our in vitro experiments showed that macrophage GIT1 plays a critical role in secreting TNFα and influences the differentiation of oligodendrocyte precursor cells (OPCs) after stimulation with myelin debris. Collectively, our data uncovered a new role of macrophage GIT1 in regulating the transformation of OPCs into mOLs, essential for functional remyelination after SCI, suggesting that macrophage GIT1 could be a promising treatment target of SCI.

Therapeutic potential of adipose-derived stem cell extracellular vesicles: from inflammation regulation to tissue repair

Inflammation is a key pathological feature of many diseases, disrupting normal tissue structure and resulting in irreversible damage. Despite the need for effective inflammation control, current treatments, including stem cell therapies, remain insufficient. Recently, extracellular vesicles secreted by adipose-derived stem cells (ADSC-EVs) have garnered attention for their significant anti-inflammatory properties. As carriers of bioactive substances, these vesicles have demonstrated potent capabilities in modulating inflammation and promoting tissue repair in conditions such as rheumatoid arthritis, osteoarthritis, diabetes, cardiovascular diseases, stroke, and wound healing. Consequently, ADSC-EVs are emerging as promising alternatives to conventional ADSC-based therapies, offering advantages such as reduced risk of immune rejection, enhanced stability, and ease of storage and handling. However, the specific mechanisms by which ADSC-EVs regulate inflammation under pathological conditions are not fully understood. This review discusses the role of ADSC-EVs in inflammation control, their impact on disease prognosis, and their potential to promote tissue repair. Additionally, it provides insights into future clinical research focused on ADSC-EV therapies for inflammatory diseases, which overcome some limitations associated with cell-based therapies.

Acellular spinal cord scaffold containing quercetin-encapsulated nanoparticles plays an anti-inflammatory role in functional recovery from spinal cord injury in rats

Inflammatory responses play a crucial role in the pathophysiology of spinal cord injury (SCI) and developing new approaches to establish an anti-inflammatory environment for the promotion of neuroregeneration holds promise as a potential approach. In this study, our aim was to investigate the potential of combining an acellular spinal cord scaffold (ASCS) with quercetin-loaded bovine serum albumin (Qu/BSA) nanoparticles (NPs) for the treatment of SCI. The ASCS was prepared using physical and chemical methods, while the Qu/BSA NPs were prepared through a desolvation technique. The NPs exhibited favorable characteristics, including a mean size of 203 nm, a zeta potential of -38, and an encapsulation efficiency of 96%. Microscopic evaluation confirmed the successful distribution of NPs on the walls of ASCS. Animal studies revealed that Qu/BSA NPs group exhibited a significant decrease in NLRP3, ASC, and Casp1 gene expression compared to the SCI group (p < 0.0001). The findings indicated a significant decrease in the NLRP3, ASC, and Casp1 protein level between the Qu/BSA/ASCS group and the SCI group (p < 0.0001). Moreover, treatment with ASCS containing either blank BSA (B/BSA) NPs or Qu/BSA NPs effectively promoted functional recovery via increasing the amount of nestin- and glial fibrillary acidic protein (GFAP)-positive cells in the site of injury. Notably, Qu/BSA/ASCS exhibited superior outcomes compared to B/BSA/ASCS. Overall, the combination of ASCS with the Qu delivery system presents a promising therapeutic approach for SCI by inhibiting inflammatory responses and promoting neuroregeneration, leading to the restoration of motor function in animals. This study demonstrates the potential of utilizing biomaterials and NPs to enhance the effectiveness of SCI treatment.

A comprehensive and systematic review of the potential neuroprotective effect of quercetin in rat models of spinal cord injury

CONTEXT

Spinal cord injury (SCI) is a potentially fatal neurological disease with severe complications and a high disability rate. An increasing number of animal experimental studies support the therapeutic effect of quercetin, which is a natural anti-inflammatory and antioxidant bioflavonoid.

OBJECTIVE

This paper reviewed the therapeutic effect of quercetin on a rat SCI model and summarized the relevant mechanistic research.

DATA SOURCES

PubMed, EMBASE, Web of Science, Science Direct, WanFang Data, SinoMed databases, the China National Knowledge Infrastructure, and the Vip Journal Integration Platform were searched from their inception to April 2023 for animal experiments applying quercetin to treat SCI.

STUDY SELECTION

Based on the PICOS criteria, a total of 18 eligible studies were included, of which 14 were high quality.

RESULTS

In this study, there was a gradual increase in effect based on the Basso, Beattie, and Bresnahan (BBB) score after three days (p < 0.0001). Furthermore, gender differences also appeared in the efficacy of quercetin; males performed better than females (p = 0.008). Quercetin was also associated with improved inclined plane test score (p = 0.008). In terms of biochemical indicators, meta-analysis showed that MDA (p < 0.0001) and MPO (p = 0.0002) were significantly reduced after quercetin administration compared with the control group, and SOD levels were increased (p = 0.004). Mechanistically, quercetin facilitates the inhibition of oxidative stress, inflammation, autophagy and apoptosis that occur after SCI.

CONCLUSIONS

Generally, this systematic review suggests that quercetin has a neuroprotective effect on SCI.

Wogonin Inhibits Apoptosis and Necroptosis Induced by Nephropathogenic Infectious Bronchitis Virus in Chicken Renal Tubular Epithelial Cells

NIBV is an acute and highly contagious virus that has a major impact on the poultry industry. Wogonin, as a flavonoid drug, has antiviral effects, but there have been no reports indicating its role in renal injury caused by NIBV infection. The aim of this study is to investigate the antiviral effect of wogonin against NIBV. Renal tubular epithelial cells were isolated and cultured, and divided into four groups: Con, Con+Wog, NIBV and NIBV+Wog. We found that wogonin significantly inhibited the copy number of NIBV and significantly alleviated NIBV-induced cell apoptosis and necrosis. Moreover, wogonin inhibited the reduction in mitochondrial membrane potential and the aberrant opening of mPTP caused by NIBV. In conclusion, wogonin can protect renal tubular epithelial cells from damage by inhibiting the replication of NIBV and preventing mitochondrial apoptosis and necroptosis induced by NIBV.

Immunoregulation of Glia after spinal cord injury: a bibliometric analysis

Objective

Immunoregulation is a complex and critical process in the pathological process of spinal cord injury (SCI), which is regulated by various factors and plays an important role in the functional repair of SCI. This study aimed to explore the research hotspots and trends of glial cell immunoregulation after SCI from a bibliometric perspective.

Methods

Data on publications related to glial cell immunoregulation after SCI, published from 2004 to 2023, were obtained from the Web of Science Core Collection. Countries, institutions, authors, journals, and keywords in the topic were quantitatively analyzed using the R package "bibliometrix", VOSviewer, Citespace, and the Bibliometrics Online Analysis Platform.

Results

A total of 613 papers were included, with an average annual growth rate of 9.39%. The papers came from 36 countries, with the United States having the highest output, initiating collaborations with 27 countries. Nantong University was the most influential institution. We identified 3,177 authors, of whom Schwartz, m, of the Weizmann Institute of Science, was ranked first regarding both field-specific H-index (18) and average number of citations per document (151.44). Glia ranked first among journals with 2,574 total citations. The keywords "microglia," "activation," "macrophages," "astrocytes," and "neuroinflammation" represented recent hot topics and are expected to remain a focus of future research.

Conclusion

These findings strongly suggest that the immunomodulatory effects of microglia, astrocytes, and glial cell interactions may be critical in promoting nerve regeneration and repair after SCI. Research on the immunoregulation of glial cells after SCI is emerging, and there should be greater cooperation and communication between countries and institutions to promote the development of this field and benefit more SCI patients.

Celastrol inhibits oligodendrocyte and neuron ferroptosis to promote spinal cord injury recovery

BACKGROUND

Spinal cord injury (SCI) is a traumatic injury to the central nervous system and can cause lipid peroxidation in the spinal cord. Ferroptosis, an iron-dependent programmed cell death, plays a key role in the pathophysiology progression of SCI. Celastrol, a widely used antioxidant drug, has potential therapeutic value for nervous system.

PURPOSE

To investigate whether celastrol can be a reliable candidate for ferroptosis inhibitor and the molecular mechanism of celastrol in repairing SCI by inhibiting ferroptosis.

METHODS

First, a rat SCI model was constructed, and the recovery of motor function was observed after treatment with celastrol. The regulatory effect of celastrol on ferroptosis pathway Nrf2-xCT-GPX4 was detected by Western blot and immunofluorescence. Finally, the ferroptosis model of neurons and oligodendrocytes was constructed in vitro to further verify the mechanism of inhibiting ferroptosis by celastrol.

RESULTS

Our results demonstrated that celastrol promoted the recovery of spinal cord tissue and motor function in SCI rats. Further in vitro and in vivo studies showed that celastrol significantly inhibited ferroptosis in neurons and oligodendrocytes and reduced the accumulation of ROS. Finally, we found that celastrol could inhibit ferroptosis by up-regulating the Nrf2-xCT-GPX4 axis to repair SCI.

CONCLUSION

Celastrol effectively inhibits ferroptosis after SCI by upregulating the Nrf2-xCT-GPX4 axis, reducing the production of lipid ROS, protecting the survival of neurons and oligodendrocytes, and improving the functional recovery.

DADLE promotes motor function recovery by inhibiting cytosolic phospholipase A2 mediated lysosomal membrane permeabilization after spinal cord injury

BACKGROUND AND PURPOSE

Autophagy is a protective factor for controlling neuronal damage, while necroptosis promotes neuroinflammation after spinal cord injury (SCI). DADLE (D-Ala2 , D-Leu5 ]-enkephalin) is a selective agonist for delta (δ) opioid receptor and has been identified as a promising drug for neuroprotection. The aim of this study was to investigate the mechanism/s by which DADLE causes locomotor recovery following SCI.

EXPERIMENTAL APPROACH

Spinal cord contusion model was used and DADLE was given by i.p. (16 mg·kg-1 ) in mice for following experiments. Motor function was assessed by footprint and Basso mouse scale (BMS) score analysis. Western blotting used to evaluate related protein expression. Immunofluorescence showed the protein expression in each cell and its distribution. Network pharmacology analysis was used to find the related signalling pathways.

KEY RESULTS

DADLE promoted functional recovery after SCI. In SCI model of mice, DADLE significantly increased autophagic flux and inhibited necroptosis. Concurrently, DADLE restored autophagic flux by decreasing lysosomal membrane permeabilization (LMP). Additionally, chloroquine administration reversed the protective effect of DADLE to inhibit necroptosis. Further analysis showed that DADLE decreased phosphorylated cPLA2 , overexpression of cPLA2 partially reversed DADLE inhibitory effect on LMP and necroptosis, as well as the promotion autophagy. Finally, AMPK/SIRT1/p38 pathway regulating cPLA2 is involved in the action DADLE on SCI and naltrindole inhibited DADLE action on δ receptor and on AMPK signalling pathway.

CONCLUSION AND IMPLICATION

DADLE causes its neuroprotective effects on SCI by promoting autophagic flux and inhibiting necroptosis by decreasing LMP via activating δ receptor/AMPK/SIRT1/p38/cPLA2 pathway.

A review on traditional Chinese medicine natural products and acupuncture intervention for Alzheimer's disease based on the neuroinflammatory

Alzheimer's disease (AD) is a neurodegenerative disease with insidious onset and progressive development. It is clinically characterized by cognitive impairment, memory impairment and behavioral change. Chinese herbal medicine and acupuncture are important components of traditional Chinese medicine (TCM), and are commonly used in clinical treatment of AD. This paper systematically summarizes the research progress of traditional Chinese medicine natural products and acupuncture treatment of AD, which combined with existing clinical and preclinical evidence, based on a comprehensive review of neuroinflammation, and discusses the efficacy and potential mechanisms of traditional Chinese medicine natural products and acupuncture treatment of AD. Resveratrol, curcumin, kaempferol and other Chinese herbal medicine components can significantly inhibit the neuroinflammation of AD in vivo and in vitro, and are candidates for the treatment of AD. Acupuncture can alleviate the memory and cognitive impairment of AD by improving neuroinflammation, synaptic plasticity, nerve cell apoptosis and reducing the production and aggregation of amyloid β protein (Aβ) in the brain. It has the characteristics of early, safe, effective and benign bidirectional adjustment. The purpose of this paper is to provide a basis for improving the clinical strategies of TCM for the treatment of AD.

TRIM65 knockout inhibits the development of HCC by polarization tumor-associated macrophages towards M1 phenotype via JAK1/STAT1 signaling pathway

BACKGROUND & AIMS

Tumor-associated macrophages (TAMs) are main components of immune cells in tumor microenvironment (TME), and play a crucial role in tumor progression. Tripartite motif-containing protein 65 (TRIM65) has been associated with tumor progression. However, whether TRIM65 regulate the interaction of tumor cell and TAMs in HCC and the underlying mechanisms remain unknown. In this study, we investigated the role of TRIM65 in TME of HCC and explored its underlying mechanisms.

METHODS

The relation of TRIM65 expression level with tumor grades, TNM stages, and worse prognosis of HCC patients was evaluated by bioinformatics analysis, as well as immune infiltration level of macrophages. TRIM65 shRNA was transfected into HepG2 cells, and TRIM65 overexpression plasmid was transfected into Huh7 cells, and the effect of TRIM65 on cell growth was examined by EdU assay. The mouse subcutaneous Hep1-6 tumor-bearing model with WT and TRIM65-/- mice was established to study the role of TRIM65 in HCC. Immunohistochemistry staining, Immunofluorescence staining, qRT-PCR and western blot were performed to evaluate the effect of TRIM65 on TAM infiltration, TAM polarization and JAK1/STAT1 signaling pathway.

RESULTS

Bioinformatics analysis revealed that TRIM65 was upregulated in 16 types of cancer especially in HCC, and high level of TRIM65 was strongly correlated with higher tumor grades, TNM stages, and worse prognosis of patients with HCC as well as immune infiltration level of macrophages (M0, M1, and M2). Moreover, we observed that TRIM65 shRNA-mediated TRIM65 knockdown significantly inhibited the HepG2 cells growth while TRIM65 overexpression highly increased the Huh7 cells growth in vitro. TRIM65 knockout significantly inhibited the tumor growth as well as macrophages polarization towards M2 but promoted macrophages polarization towards M1 in vivo. Mechanistically, the results demonstrate that TRIM65 knockout promoted macrophage M1 polarization in conditioned medium-stimulated peritoneal macrophages and in tumor tissues by activating JAK1/STAT1 signaling pathway.

CONCLUSIONS

Taken together, our study suggests that tumor cells utilize TRIM65-JAK1/STAT1 axis to inhibit macrophage M1 polarization and promote tumor growth, reveals the role of TRIM65 in TAM-targeting tumor immunotherapy.

From Plant to Chemistry: Sources of Antinociceptive Non-Opioid Active Principles for Medicinal Chemistry and Drug Design

Pain is associated with many health problems and a reduced quality of life and has been a common reason for seeking medical attention. Several therapeutics are available on the market, although side effects, physical dependence, and abuse limit their use. As the process of pain transmission and modulation is regulated by different peripheral and central mechanisms and neurotransmitters, medicinal chemistry continues to study novel ligands and innovative approaches. Among them, natural products are known to be a rich source of lead compounds for drug discovery due to their chemical structural variety and different analgesic mechanisms. Numerous studies suggested that some chemicals from medicinal plants could be alternative options for pain relief and management. Previously, we conducted a literature search aimed at identifying natural products interacting either directly or indirectly with opioid receptors. In this review, instead, we have made an excursus including active ingredients derived from plants whose mechanism of action appears from the literature to be other than the modulation of the opioid system. These substances could, either by themselves or through synthetic and/or semi-synthetic derivatives, be investigated in order to improve their pharmacokinetic characteristics and could represent a valid alternative to the opioid approach to pain therapy. They could also be the basis for the study of new mechanisms of action in the approach to this complex and disabling pathology.

A High MCT-Based Ketogenic Diet Suppresses Th1 and Th17 Responses to Ameliorate Experimental Autoimmune Encephalomyelitis in Mice by Inhibiting GSDMD and JAK2-STAT3/4 Pathways

SCOPE

Inflammation and pyroptosis play important roles in the pathogenesis of multiple sclerosis (MS) and experimental autoimmune encephalomyelitis (EAE). In this study, we evaluated the therapeutic potential of ketogenic diet (KD) in EAE.

METHODS AND RESULTS

The administration of KD reduces demyelination and microglial activation in the spinal cord of EAE mice. Meanwhile, KD decreases the levels of Th1 and Th17 associated cytokines/transcription factors production (T-bet, IFN-γ, RORγt, and IL-17) and increases those of Th2 and Treg cytokines/transcription factors (GATA3, IL-4, Foxp3, and IL-10) in the spinal cord and spleen. Corresponding, KD reduces the expression of chemokines in EAE, which those chemokines associate with T-cell infiltration into central nervous system (CNS). In addition, KD inhibits the GSDMD activation in microglia, oligodendrocyte, CD31+ cells, CCR2+ cells, and T cells in the spinal cord. Moreover, KD significantly decreases the ratios of p-JAK2/JAK2, p-STAT3/STAT3, and p-STAT4/STAT4, as well as GSDMD in EAE mice.

CONCLUSIONS

this study demonstrates that KD reduces the activation and differentiation of T cells in the spinal cord and spleen and prevents T cell infiltration into CNS of EAE via modulating the GSDMD and STAT3/4 pathways, suggesting that KD is a potentially effective strategy in the treatment of MS.

Maternal quercetin supplementation improved lipopolysaccharide-induced cognitive deficits and inflammatory response in a rat model of maternal immune activation

BACKGROUND

There is strong evidence that prenatal infection during a specific period of brain development increases the risk of neurodevelopmental disorders, partly through immune-inflammatory pathways. This suggests that anti-inflammatory agents could prevent these disorders by targeting the maternal inflammatory response. In the present study, we used a rat model of maternal immune activation (MIA) to examine whether maternal quercetin (QE) supplementation can alleviate behavioral deficits and inflammatory mediators in the prefrontal cortex (PFC) and hippocampus of adult male offspring.

METHODS

Pregnant rats were supplemented with QE (50 mg/kg) or vehicle throughout pregnancy and injected with either lipopolysaccharide (0.5 mg/kg) or saline on gestational days 15/16. At postnatal day 60, we evaluated the offspring's behavior, hippocampal and prefrontal cortex glial density, pro-inflammatory gene expression, and neuronal survival.

RESULTS

Our data showed that maternal QE supplementation can prevent working and recognition memory impairments in adult MIA offspring. This behavioral improvement correlates with the decrease in MIA-induced expression of pro-inflammatory genes, microglia, and astrocyte densities, without affecting neuronal survival, in both PFC and CA1 hippocampus areas.

CONCLUSION

Therefore, our study supports the potential preventive effect of QE on MIA-induced behavioral dysfunctions, at least in part, by suppressing the glial-mediated inflammatory response.

Quercetin inhibits caspase-1-dependent macrophage pyroptosis in experimental folic acid nephropathy

BACKGROUND

The role of pyroptosis in kidney disease is limited and incomplete. Quercetin, a flavonoid compound present in a variety of fruits, vegetables, and plants, has shown antioxidant and anti-inflammatory properties. This study was designed to validate the importance of pyroptosis in an experimental model of folic acid nephropathy and to explore the effect of quercetin in protecting against pyroptosis.

METHODS

Gene set enrichment analysis (GSEA) and weighted gene co-expression network analysis (WGCNA) were used to establish the correlation between pyroptosis and folic acid nephropathy. Immune cell infiltration, network pharmacology and single-cell RNA sequencing analysis were utilized to ascertain the specific target of quercetin in relation to pyroptosis. Finally, quercetin's role was verified in vivo and in vitro.

RESULTS

The GSEA analysis revealed a significant correlation between pyroptosis and folic acid nephropathy (NES = 1.764, P = 0.004). The hub genes identified through WGCNA were closely associated with inflammation. Molecular docking demonstrated a strong binding affinity between quercetin and caspase-1, a protein known to be involved in macrophage function, as confirmed by immune cell infiltration and single-cell analysis. Quercetin demonstrated a significant amelioration of kidney injury and reduction in macrophage infiltration in the animal model. Furthermore, quercetin exhibited a significant inhibition of caspase-1 expression, subsequently leading to the inhibition of pro-inflammatory cytokines expression, such as IL-1β, IL-18, TNF-α, and IL-6. The inhibitory effect of quercetin on macrophage pyroptosis was also confirmed in RAW264.7 cells.

CONCLUSION

This study contributes substantial evidence to support the significant role of pyroptosis in the development of folic acid nephropathy, and highlights the ability of quercetin to downregulate caspase-1 in macrophages as a protective mechanism against pyroptosis.

Exosome-mediated repair of spinal cord injury: a promising therapeutic strategy

Spinal cord injury (SCI) is a catastrophic injury to the central nervous system (CNS) that can lead to sensory and motor dysfunction, which seriously affects patients' quality of life and imposes a major economic burden on society. The pathological process of SCI is divided into primary and secondary injury, and secondary injury is a cascade of amplified responses triggered by the primary injury. Due to the complexity of the pathological mechanisms of SCI, there is no clear and effective treatment strategy in clinical practice. Exosomes, which are extracellular vesicles of endoplasmic origin with a diameter of 30-150 nm, play a critical role in intercellular communication and have become an ideal vehicle for drug delivery. A growing body of evidence suggests that exosomes have great potential for repairing SCI. In this review, we introduce exosome preparation, functions, and administration routes. In addition, we summarize the effect and mechanism by which various exosomes repair SCI and review the efficacy of exosomes in combination with other strategies to repair SCI. Finally, the challenges and prospects of the use of exosomes to repair SCI are described.

Macrophage polarization in spinal cord injury repair and the possible role of microRNAs: A review

The prevention, treatment, and rehabilitation of spinal cord injury (SCI) have always posed significant medical challenges. After mechanical injury, disturbances in microcirculation, edema formation, and the generation of free radicals lead to additional damage, impeding effective repair processes and potentially exacerbating further dysfunction. In this context, inflammatory responses, especially the activation of macrophages, play a pivotal role. Different phenotypes of macrophages have distinct effects on inflammation. Activation of classical macrophage cells (M1) promotes inflammation, while activation of alternative macrophage cells (M2) inhibits inflammation. The polarization of macrophages is crucial for disease healing. A non-coding RNA, known as microRNA (miRNA), governs the polarization of macrophages, thereby reducing inflammation following SCI and facilitating functional recovery. This study elucidates the inflammatory response to SCI, focusing on the infiltration of immune cells, specifically macrophages. It examines their phenotype and provides an explanation of their polarization mechanisms. Finally, this paper introduces several well-known miRNAs that contribute to macrophage polarization following SCI, including miR-155, miR-130a, and miR-27 for M1 polarization, as well as miR-22, miR-146a, miR-21, miR-124, miR-223, miR-93, miR-132, and miR-34a for M2 polarization. The emphasis is placed on their potential therapeutic role in SCI by modulating macrophage polarization, as well as the present developments and obstacles of miRNA clinical therapy.

Quercetin improves cerebral ischemia/reperfusion injury by promoting microglia/macrophages M2 polarization via regulating PI3K/Akt/NF-κB signaling pathway

The modulation of microglial polarization from the pro-inflammatory M1 to the anti-inflammatory M2 phenotype shows promise as a therapeutic strategy for ischemic stroke. Quercetin, a natural flavonoid abundant in various plants, possesses anti-inflammatory, anti-apoptotic, and antioxidant properties. Nevertheless, its effect and underlying mechanism on microglia/macrophages M1/M2 polarization in the treatment of cerebral ischemia/reperfusion injury (CI/RI) remain poorly explored. In the current study, we observed that quercetin ameliorated neurological deficits, reduced infarct volume, decreased the number of M1 microglia/macrophages (CD16/32+/Iba1+), and enhanced the number of M2 microglia/macrophages (CD206+/Iba1+) after establishing the CI/RI model in rats. Subsequent in vivo and in vitro experiments indicated that quercetin downregulated M1 markers (CD86, iNOS, TNF-α, IL-1β, and IL-6) and upregulated M2 markers (CD206, Arg-1, IL-10, and TGF-β). Network pharmacology analysis and molecular docking revealed that the PI3K/Akt/NF-κB signaling pathway emerged as the core pathway. Western blot confirmed that quercetin upregulated the phosphorylation of PI3K and Akt, while alleviating the phosphorylation of IκBα and NF-κB both in vivo and in vitro. However, the PI3K inhibitor LY294002 reversed the effects of quercetin on M2 polarization and the expression of key proteins in the PI3K/Akt/NF-κB pathway in primary microglia after oxygen-glucose deprivation/reoxygenation (OGD/R) in vitro. Collectively, our findings demonstrate that quercetin facilitates microglia/macrophages M2 polarization by modulating the PI3K/Akt/NF-κB signaling pathway in the treatment of CI/RI. These findings provide novel insights into the therapeutic mechanisms of quercetin in ischemic stroke.