Does combined therapy of curcumin and epigallocatechin gallate have a synergistic neuroprotective effect against spinal cord injury?

Combinatorial therapies for spinal cord injury repair

Spinal cord injuries have profound detrimental effects on individuals, regardless of whether they are caused by trauma or non-traumatic events. The compromised regeneration of the spinal cord is primarily attributed to damaged neurons, inhibitory molecules, dysfunctional immune response, and glial scarring. Unfortunately, currently, there are no effective treatments available that can fully repair the spinal cord and improve functional outcomes. Nevertheless, numerous pre-clinical approaches have been studied for spinal cord injury recovery, including using biomaterials, cells, drugs, or technological-based strategies. Combinatorial treatments, which target various aspects of spinal cord injury pathophysiology, have been extensively tested in the last decade. These approaches aim to synergistically enhance repair processes by addressing various obstacles faced during spinal cord regeneration. Thus, this review intends to provide scientists and clinicians with an overview of pre-clinical combinatorial approaches that have been developed toward the solution of spinal cord regeneration as well as update the current knowledge about spinal cord injury pathophysiology with an emphasis on the current clinical management.

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.

Epigallocatechin 3-gallate-induced neuroprotection in neurodegenerative diseases: molecular mechanisms and clinical insights

Neurodegenerative diseases (NDs) are caused by progressive neuronal death and cognitive decline. Epigallocatechin 3-gallate (EGCG) is a polyphenolic molecule in green tea as a neuroprotective agent. This review evaluates the therapeutic effects of EGCG and explores the molecular mechanisms that show its neuroprotective properties. EGCG protects neurons in several ways, such as by lowering oxidative stress, stopping Aβ from aggregation together, changing cell signaling pathways, and decreasing inflammation. Furthermore, it promotes autophagy and improves mitochondrial activity, supporting neuronal survival. Clinical studies have demonstrated that EGCG supplementation can reduce neurodegenerative biomarkers and enhance cognitive function. This review provides insights into the molecular mechanisms and therapeutic potential of EGCG in treating various NDs. EGCG reduces oxidative stress by scavenging free radicals and enhancing antioxidant enzyme activity, aiding neuronal defense. It also protects neurons and improves cognitive abilities by inhibiting the toxicity and aggregation of Aβ peptides. It changes important cell signaling pathways like Nrf2, PI3K/Akt, and MAPK, which are necessary for cell survival, cell death, and inflammation. Additionally, it has strong anti-inflammatory properties because it inhibits microglial activation and downregulates pro-inflammatory cytokines. It improves mitochondrial function by reducing oxidative stress, increasing ATP synthesis, and promoting mitochondrial biogenesis, which promotes neurons' survival and energy metabolism. In addition, it also triggers autophagy, a cellular process that breaks down and recycles damaged proteins and organelles, eliminating neurotoxic aggregates and maintaining cellular homeostasis. Moreover, it holds significant promise as an ND treatment, but future research should focus on increasing bioavailability and understanding its long-term clinical effects. Future studies should focus on improving EGCG delivery and understanding its long-term effects in therapeutic settings. It can potentially be a therapeutic agent for managing NDs, indicating a need for further research.

Mechanistic insight of curcumin: a potential pharmacological candidate for epilepsy

Recurrent spontaneous seizures with an extended epileptic discharge are the hallmarks of epilepsy. At present, there are several available anti-epileptic drugs (AEDs) in the market. Still no adequate treatment for epilepsy treatment is available. The main disadvantages of AEDs are their associated adverse effects. It is a challenge to develop new therapies that can reduce seizures by modulating the underlying mechanisms with no adverse effects. In the last decade, the neuromodulatory potential of phytoconstituents has sparked their usage in the treatment of central nervous system disorders. Curcumin is an active polyphenolic component that interacts at cellular and molecular levels. Curcumin's neuroprotective properties have been discovered in recent preclinical and clinical studies due to its immunomodulatory effects. Curcumin has the propensity to modulate signaling pathways involved in cell survival and manage oxidative stress, apoptosis, and inflammatory mechanisms. Further, curcumin can persuade epigenetic alterations, including histone modifications (acetylation/deacetylation), which are the changes responsible for the altered expression of genes facilitating the process of epileptogenesis. The bioavailability of curcumin in the brain is a concern that needs to be tackled. Therefore, nanonization has emerged as a novel drug delivery system to enhance the pharmacokinetics of curcumin. In the present review, we reviewed curcumin's modulatory effects on potential biomarkers involved in epileptogenesis including dendritic cells, T cell subsets, cytokines, chemokines, apoptosis mediators, antioxidant mechanisms, and cognition impairment. Also, we have discussed the nanocarrier systems for encapsulating curcumin, offering a promising approach to enhance bioavailability of curcumin.

TRIM24-DTNBP1-ATP7A mediated astrocyte cuproptosis in cognition and memory dysfunction caused by Y2O3 NPs

Yttrium oxide nanoparticles (Y2O3 NPs), extensively utilized rare earth nanoparticles, exhibited a diverse range of applications across various fields, which leading to increased human exposure. Moreover, potential neurotoxic risks have been associated with their use, yet the underlying mechanism remains unclear. The present study aimed to investigate the effects of Y2O3 NPs on cognitive function in rats with a particular focus on elucidating the pivotal role played by astrocytes in this process. The results demonstrated that Y2O3 NPs induced cognitive and memory impairment in rats, copper (Cu) accumulation and cuproptosis of astrocytes as contributing factors. Furthermore, we elucidated that Y2O3 NPs induced astrocytes cuproptosis by inhibiting TRIM24/DTNBP1/ATP7A signaling pathway-mediated cellular Cu efflux. We provide, for the first time, the important involvement of astrocytes in Y2O3 NPs-induced neurotoxicity, elucidating that cuproptosis as the primary mode of cell death. These results offer valuable insights for the future safe application of rare earth nanoparticles in field of neurology.

Curcumin/pEGCG-encapsulated nanoparticles enhance spinal cord injury recovery by regulating CD74 to alleviate oxidative stress and inflammation

Spinal cord injury (SCI) often accompanies impairment of motor function, yet there is currently no highly effective treatment method specifically for this condition. Oxidative stress and inflammation are pivotal factors contributing to severe neurological deficits after SCI. In this study, a type of curcumin (Cur) nanoparticle (HA-CurNPs) was developed to address this challenge by alleviating oxidative stress and inflammation. Through non-covalent interactions, curcumin (Cur) and poly (-)-epigallocatechin-3-gallate (pEGCG) are co-encapsulated within hyaluronic acid (HA), resulting in nanoparticles termed HA-CurNPs. These nanoparticles gradually release curcumin and pEGCG at the SCI site. The released pEGCG and curcumin not only scavenge reactive oxygen species (ROS) and prevents apoptosis, thereby improving the neuronal microenvironment, but also regulate CD74 to promote microglial polarization toward an M2 phenotype, and inhibits M1 polarization, thereby suppressing the inflammatory response and fostering neuronal regeneration. Moreover, in vivo experiments on SCI mice demonstrate that HA-CurNPs effectively protect neuronal cells and myelin, reduce glial scar formation, thereby facilitating the repair of damaged spinal cord tissues, restoring electrical signaling at the injury site, and improving motor functions. Overall, this study demonstrates that HA-CurNPs significantly reduce oxidative stress and inflammation following SCI, markedly improving motor function in SCI mice. This provides a promising therapeutic approach for the treatment of SCI.

Combined transcriptomics and proteomics studies on the effect of electrical stimulation on spinal cord injury in rats

Electrical stimulation (ES) of the spinal cord is a promising therapy for functional rehabilitation after spinal cord injury (SCI). However, the specific mechanism of action is poorly understood. We designed and applied an implanted ES device in the SCI area in rats and determined the effect of ES on the treatment of motor dysfunction after SCI using behavioral scores. Additionally, we examined the molecular characteristics of the samples using proteomic and transcriptomic sequencing. The differential molecules between groups were identified using statistical analyses. Molecular, network, and pathway-based analyses were used to identify group-specific biological features. ES (0.5 mA, 0.1 ms, 50 Hz) had a positive effect on motor dysfunction and neuronal regeneration in rats after SCI. Six samples (three independent replicates in each group) were used for transcriptome sequencing; we obtained 1026 differential genes, comprising 274 upregulated genes and 752 downregulated genes. A total of 10 samples were obtained: four samples in the ES group and six samples in the SCI group; for the proteome sequencing, 48 differential proteins were identified, including 45 up-regulated and three down-regulated proteins. Combined transcriptomic and proteomic studies have shown that the main enrichment pathway is the hedgehog signaling pathway. Western blot results showed that the expression levels of Sonic hedgehog (SHH) (P < 0.001), Smoothened (SMO) (P = 0.0338), and GLI-1 (P < 0.01) proteins in the ES treatment group were significantly higher than those in the SCI group. The immunofluorescence results showed significantly increased expression of SHH (P = 0.0181), SMO (P = 0.021), and GLI-1 (P = 0.0126) in the ES group compared with that in the SCI group. In conclusion, ES after SCI had a positive effect on motor dysfunction and anti-inflammatory effects in rats. Moreover, transcriptomic and proteomic sequencing also provided unique perspectives on the complex relationships between ES on SCI, where the SHH signaling pathway plays a critical role. Our study provides a significant theoretical foundation for the clinical implementation of ES therapy in patients with SCI.

Enhanced spinal cord regeneration by gelatin/alginate hydrogel scaffolds containing human endometrial stem cells and curcumin-loaded PLGA nanoparticles in rat

Spinal cord injury (SCI) is a serious problem with a high prevalence worldwide. The weak capability of the spinal cord for regeneration in association with upregulation of inflammatory factors is two key obstacles against a full SCI repair. Curcumin is a natural substance with anti-inflammatory and neuroprotective effects. Here, we have used a combined strategy using stem cells and hybrid hydrogel scaffolds loaded with curcumin for SCI repair. Curcumin-loaded PLGA nanoparticles were prepared, characterized, and encapsulated into gelatin/alginate hydrogel scaffolds, which were then seeded by human endometrial stem cells (hEnSCs). The resulting construct was studied using in vitro and in vivo experiments on rat models. DLS, SEM, Zeta potential, and FTIR data confirmed the successful addition of curcumin to PLGA nanoparticles. SEM analyses indicated the successful addition of curcumin-loaded nanoparticles into the gelatin/alginate scaffold, as well as the adherence of the seeded EnSCs. Based on the results, the prepared constructs not only allowed the controlled release of curcumin but also could support the survival and growth of hEnSCs. Based on the results of BBB and histological experiments, the highest BBB score was related to the combined strategy, consistent with histological outcomes, in which our hEnSC-seeded gelatin/alginate scaffold containing curcumin-loaded nanoparticles led to improved structures of the white and gray matters in the SCI site, being indicative of the superior nerve fiber regeneration, compared to other studied groups. These results indicate the efficiency of the proposed method for SCI repair and broaden the scope for subsequent studies on spinal cord regeneration.

Neuron-immunity communication: mechanism of neuroprotective effects in EGCG

Epigallocatechin gallate (EGCG), a naturally occurring active ingredient unique to tea, has been shown to have neuroprotective potential. There is growing evidence of its potential advantages in the prevention and treatment of neuroinflammation, neurodegenerative diseases, and neurological damage. Neuroimmune communication is an important physiological mechanism in neurological diseases, including immune cell activation and response, cytokine delivery. EGCG shows great neuroprotective potential by modulating signals related to autoimmune response and improving communication between the nervous system and the immune system, effectively reducing the inflammatory state and neurological function. During neuroimmune communication, EGCG promotes the secretion of neurotrophic factors into the repair of damaged neurons, improves intestinal microenvironmental homeostasis, and ameliorates pathological phenotypes through molecular and cellular mechanisms related to the brain-gut axis. Here, we discuss the molecular and cellular mechanisms of inflammatory signaling exchange involving neuroimmune communication. We further emphasize that the neuroprotective role of EGCG is dependent on the modulatory role between immunity and neurology in neurologically related diseases.

Multiple mechanisms of curcumin targeting spinal cord injury

Spinal cord injury (SCI) is an irreversible disease process with a high disability and mortality rate. After primary spinal cord injury, the secondary injury may occur in sequence, which is composed of ischemia and hypoxia, excitotoxicity, calcium overload, oxidative stress and inflammation, resulting in massive death of parenchymal cells in the injured area, followed by the formation of syringomyelia. Effectively curbing the process of secondary injury can promote nerve repair and improve functional prognosis. As the main active ingredient in turmeric, curcumin can play an important role in reducing inflammation and oxidation, protecting the neurons, and ultimately reducing spinal cord injury. This article reviews the effects of curcumin on the repair of nerve injury, with emphasis on the various mechanisms by which curcumin promotes the treatment of spinal cord injury.

The Role of Green Tea Catechin Epigallocatechin Gallate (EGCG) and Mammalian Target of Rapamycin (mTOR) Inhibitor PP242 (Torkinib) in the Treatment of Spinal Cord Injury

Spinal cord injury (SCI) is a devastating condition that has physical and psychological consequences for patients. SCI is accompanied by scar formation and systemic inflammatory response leading to an intense degree of functional loss. The catechin, epigallocatechin gallate (EGCG), an active compound found in green tea, holds neuroprotective features and is known for its anti-inflammatory potential. The mammalian target of rapamycin (mTOR) is a serine/threonine kinase that exists in two functionally distinct complexes termed mTOR complex 1 and 2 (mTORC1; mTORC2). Inhibition of mTORC1 by rapamycin causes neuroprotection, leading to partial recovery from SCI. In this study the effects of EGCG, PP242 (an inhibitor of both complexes of mTOR), and a combination of EGCG and PP242 in SCI have been examined. It has been found that both EGCG and PP242 significantly improved sensory/motor functions following SCI. However, EGCG appeared to be more effective (BBB motor test, from 2 to 8 weeks after SCI, p = 0.019, p = 0.007, p = 0.006, p = 0.006, p = 0.05, p = 0.006, and p = 0.003, respectively). The only exception was the Von Frey test, where EGCG was ineffective, while mTOR inhibition by PP242, as well as PP242 in combination with EGCG, significantly reduced withdrawal latency starting from week three (combinatorial therapy (EGCG + PP242) vs. control at 3, 5, and 7 weeks, p = 0.011, p = 0.007, and p = 0.05, respectively). It has been found that EGCG was as effective as PP242 in suppressing mTOR signaling pathways, as evidenced by a reduction in phosphorylated S6 expression (PP242 (t-test, p < 0.0001) or EGCG (t-test, p = 0.0002)). These results demonstrate that EGCG and PP242 effectively suppress mTOR pathways, resulting in recovery from SCI in rats, and that EGCG acts via suppressing mTOR pathways.

Impacts of turmeric and its principal bioactive curcumin on human health: Pharmaceutical, medicinal, and food applications: A comprehensive review

The yellow polyphenolic pigment known as curcumin, originating from the rhizome of the turmeric plant Curcuma longa L., has been utilized for ages in ancient medicine, as well as in cooking and food coloring. Recently, the biological activities of turmeric and curcumin have been thoroughly investigated. The studies mainly focused on their antioxidant, antitumor, anti-inflammatory, neuroprotective, hepatoprotective, and cardioprotective impacts. This review seeks to provide an in-depth, detailed discussion of curcumin usage within the food processing industries and its effect on health support and disease prevention. Curcumin's bioavailability, bio-efficacy, and bio-safety characteristics, as well as its side effects and quality standards, are also discussed. Finally, curcumin's multifaceted uses, food appeal enhancement, agro-industrial techniques counteracting its instability and low bioavailability, nanotechnology and focused drug delivery systems to increase its bioavailability, and prospective clinical use tactics are all discussed.

Curcumin as a Promising Neuroprotective Agent for the Treatment of Spinal Cord Injury: A Review of the Literature

Curcumin is a polyphenolic chemical derived from the rhizomes of Curcuma longa. It has been used throughout the Indian subcontinent for medicinal purposes, religious events, and regional cuisine. It has various pharmacological benefits owing to its anti-inflammatory and antioxidant properties. Its neuroprotective effects on the brain and peripheral nerves have been demonstrated in several in vivo neuronal tissue studies. Because of these functional properties of curcumin, it is considered to have great potential for use in the treatment of spinal cord injuries (SCIs). Numerous immunopathological and biochemical studies have reported that curcumin can help prevent and alleviate subsequent secondary injuries, such as inflammation, edema, free radical damage, fibrosis, and glial scarring, after a primary SCI. Furthermore, following SCI, curcumin administration resulted in better outcomes of neurological function recovery as per the Basso, Beattie, and Bresnahan locomotor rating scale. However, to date, its utility in treating SCIs has only been reported in laboratories. More studies on its clinical applications are needed in the future for ensuring its bioavailability across the blood-brain barrier and for verifying the safe dose for treating SCIs in humans.

The potential of curcumin for treating spinal cord injury: a meta-analysis study

INTRODUCTION

In this paper, we conducted a meta-analysis on the curcumin effect on functional recovery provided by the Basso, Beattie, Brenham (BBB) test for rats, and the Basso mouse scale (BMS) for mice after spinal cord injury (SCI) in animal models.

METHOD

Data mining was performed, and the standard mean difference (SMD) between the treated and control (untreated) groups was calculated using the STATA software. Quality control and subgroup analysis were performed.

RESULTS

The analysis includes 24 experimental studies that showed curcumin had a strong significance in improving functional recovery after SCI (SMD = 3.38; 95% CI: 2.54-4.22; p < 0.001). When curcumin was administered daily, it had a stronger effect than single-dose treatment or weekly administration. Despite the same effect in the follow-up time before and after 4 weeks post-injury, but later 9 weeks, curcumin had only a moderate effect. Curcumin also significantly reduced the expression of GFAP (Glial fibrillary acidic protein) marker compared to untreated groups.

CONCLUSION

These findings suggest that daily administration of curcumin can be an effective approach to improving functional recovery after SCI.

Effects of Polyphenols on Oxidative Stress, Inflammation, and Interconnected Pathways during Spinal Cord Injury

Despite the progression in targeting the complex pathophysiological mechanisms of neurodegenerative diseases (NDDs) and spinal cord injury (SCI), there is a lack of effective treatments. Moreover, conventional therapies suffer from associated side effects and low efficacy, raising the need for finding potential alternative therapies. In this regard, a comprehensive review was done regarding revealing the main neurological dysregulated pathways and providing alternative therapeutic agents following SCI. From the mechanistic point, oxidative stress and inflammatory pathways are major upstream orchestras of cross-linked dysregulated pathways (e.g., apoptosis, autophagy, and extrinsic mechanisms) following SCI. It urges the need for developing multitarget therapies against SCI complications. Polyphenols, as plant-derived secondary metabolites, have the potential of being introduced as alternative therapeutic agents to pave the way for treating SCI. Such secondary metabolites presented modulatory effects on neuronal oxidative stress, neuroinflammatory, and extrinsic axonal dysregulated pathways in the onset and progression of SCI. In the present review, the potential role of phenolic compounds as critical phytochemicals has also been revealed in regulating upstream dysregulated oxidative stress/inflammatory signaling mediators and extrinsic mechanisms of axonal regeneration after SCI in preclinical and clinical studies. Additionally, the coadministration of polyphenols and stem cells has shown a promising strategy for improving post-SCI complications.

Biomedical Applications and Bioavailability of Curcumin-An Updated Overview

Curcumin, a yellow-colored molecule derived from the rhizome of Curcuma longa, has been identified as the bioactive compound responsible for numerous pharmacological activities of turmeric, including anticancer, antimicrobial, anti-inflammatory, antioxidant, antidiabetic, etc. Nevertheless, the clinical application of curcumin is inadequate due to its low solubility, poor absorption, rapid metabolism and elimination. Advancements in recent research have shown several components and techniques to increase the bioavailability of curcumin. Combining with adjuvants, encapsulating in carriers and formulating in nanoforms, in combination with other bioactive agents, synthetic derivatives and structural analogs of curcumin, have shown increased efficiency and bioavailability, thereby augmenting the range of applications of curcumin. The scope for incorporating biotechnology and nanotechnology in amending the current drawbacks would help in expanding the biomedical applications and clinical efficacy of curcumin. Therefore, in this review, we provide a comprehensive overview of the plethora of therapeutic potentials of curcumin, their drawbacks in efficient clinical applications and the recent advancements in improving curcumin's bioavailability for effective use in various biomedical applications.

Nutritional interventions for spinal cord injury: preclinical efficacy and molecular mechanisms

Spinal cord injury (SCI) is a debilitating condition that leads to motor, sensory, and autonomic impairments. Its intrinsic pathophysiological complexity has hindered the establishment of effective treatments for decades. Nutritional interventions (NIs) for SCI have been proposed as a route to circumvent some of the problems associated with this condition. Results obtained in animal models point to a more holistic effect, rather than to specific modulation, of several relevant SCI pathophysiological processes. Indeed, published data have shown NI improves energetic imbalance, oxidative damage, and inflammation, which are promoters of improved proteostasis and neurotrophic signaling, leading ultimately to neuroprotection and neuroplasticity. This review focuses on the most well-documented Nis. The mechanistic implications and their translational potential for SCI are discussed.

AAV Delivery of shRNA Against TRPC6 in Mouse Hippocampus Impairs Cognitive Function

Transient Receptor Potential Canonical 6 (TRPC6) has been suggested to be involved in synapse function and contribute to hippocampal-dependent cognitive processes. Gene silencing of TRPC6 was performed by injecting adeno-associated virus (AAV) expressing TRPC6-specific shRNA (shRNA-TRPC6) into the hippocampal dentate gyrus (DG). Spatial learning, working memory and social recognition memory were impaired in the shRNA-TRPC6 treated mice compared to control mice after 4 weeks. In addition, gene ontology (GO) analysis of RNA-sequencing revealed that viral intervention of TRPC6 expression in DG resulted in the enrichment of the process of synaptic transmission and cellular compartment of synaptic structure. KEGG analysis showed PI3K-Akt signaling pathway were significantly down-regulated. Furthermore, the shRNA-TRPC6 treatment reduced dendritic spines of DG granule neurons, in terms of spine loss, the thin and mushroom types predominated. Accompanying the spine loss, the levels of PSD95, pAkt and CREB in the hippocampus were decreased in the shRNA-TRPC6 treated animals. Taken together, our results suggest that knocking down TRPC6 in the DG have a disadvantageous effect on cognitive processes.

New Model of Ventral Spinal Cord Lesion Induced by Balloon Compression in Rats

Despite the variety of experimental models of spinal cord injury (SCI) currently used, the model of the ventral compression cord injury, which is commonly seen in humans, is very limited. Ventral balloon compression injury reflects the common anatomical mechanism of a human lesion and has the advantage of grading the injury severity by controlling the inflated volume of the balloon. In this study, ventral compression of the SCI was performed by the anterior epidural placement of the balloon of a 2F Fogarty's catheter, via laminectomy, at the level of T10. The balloon was rapidly inflated with 10 or 15 μL of saline and rested in situ for 5 min. The severity of the lesion was assessed by behavioral and immunohistochemical tests. Compression with the volume of 15 μL resulted in severe motor and sensory deficits represented by the complete inability to move across a horizontal ladder, a final Basso, Beattie and Bresnahan (BBB) score of 7.4 and a decreased withdrawal time in the plantar test (11.6 s). Histology and immunohistochemistry revealed a significant loss of white and gray matter with a loss of motoneuron, and an increased size of astrogliosis. An inflation volume of 10 μL resulted in a mild transient deficit. There are no other balloon compression models of ventral spinal cord injury. This study provided and validated a novel, easily replicable model of the ventral compression SCI, introduced by an inflated balloon of Fogarty´s catheter. For a severe incomplete deficit, an inflated volume should be maintained at 15 μL.

Tanshinone IIA attenuates neuroinflammation via inhibiting RAGE/NF-κB signaling pathway in vivo and in vitro

Background

Glial activation and neuroinflammation play a crucial role in the pathogenesis and development of Alzheimer’s disease (AD). The receptor for advanced glycation end products (RAGE)-mediated signaling pathway is related to amyloid beta (Aβ)-induced neuroinflammation. This study aimed to investigate the neuroprotective effects of tanshinone IIA (tan IIA), a natural product isolated from traditional Chinese herbal Salvia miltiorrhiza Bunge, against Aβ-induced neuroinflammation, cognitive impairment, and neurotoxicity as well as the underlying mechanisms in vivo and in vitro.

Methods

Open-field test, Y-maze test, and Morris water maze test were conducted to assess the cognitive function in APP/PS1 mice. Immunohistochemistry, immunofluorescence, thioflavin S (Th-S) staining, enzyme-linked immunosorbent assay (ELISA), real-time quantitative reverse-transcription polymerase chain reaction (qRT-PCR), and western blotting were performed to explore Aβ deposition, synaptic and neuronal loss, microglial and astrocytic activation, RAGE-dependent signaling, and the production of pro-inflammatory cytokines in APP/PS1 mice and cultured BV2 and U87 cells.

Results

Tan IIA treatment prevented spatial learning and memory deficits in APP/PS1 mice. Additionally, tan IIA attenuated Aβ accumulation, synapse-associated proteins (Syn and PSD-95) and neuronal loss, as well as peri-plaque microgliosis and astrocytosis in the cortex and hippocampus of APP/PS1 mice. Furthermore, tan IIA significantly suppressed RAGE/nuclear factor-κB (NF-κB) signaling pathway and the production of pro-inflammatory cytokines (TNF-α, IL-6, and IL-1β) in APP/PS1 mice and cultured BV2 and U87 cells.

Conclusions

Taken together, the present results indicated that tan IIA improves cognitive decline and neuroinflammation partly via inhibiting RAGE/NF-κB signaling pathway in vivo and in vitro. Thus, tan IIA might be a promising therapeutic drug for halting and preventing AD progression.

Silencing of LRP1 Exacerbates Inflammatory Response Via TLR4/NF-κB/MAPKs Signaling Pathways in APP/PS1 Transgenic Mice

Activation of glial cells (including microglia and astrocytes) appears central to the initiation and progression of neuroinflammation in Alzheimer's disease (AD). The low-density lipoprotein receptor-related protein 1 (LRP1) is a major receptor for amyloid-β (Aβ), which plays a critical role in AD pathogenesis. LRP1 regulates inflammatory response by modulating the release of pro-inflammatory cytokines and phagocytosis. However, the effects of LRP1 on microglia- and astrocytic cell-mediated neuroinflammation and their underlying mechanisms in AD remain unclear. Therefore, using APP/PS1 transgenic mice, we found that LRP1 is downregulated during disease progression. Silencing of brain LRP1 markedly exacerbated AD-related neuropathology including Aβ deposition, neuroinflammation, and synaptic and neuronal loss, which was accompanied by a decline in spatial cognitive ability. Further mechanistic study revealed that silencing of LRP1 initiated neuroinflammation by increasing microgliosis and astrogliosis, enhancing pro-inflammatory cytokine production, and regulating toll-like receptor 4 (TLR4)-mediated activation of nuclear factor-kappa B (NF-κB) and mitogen-activated protein kinase (MAPK) signaling pathways. Taken together, these findings indicated that LRP1 suppresses microglia and astrocytic cell activation by modulating TLR4/NF-κB/MAPK signaling pathways. Our results further provide insights into the role of LRP1 in AD pathogenesis and highlight LRP1 as a potential therapeutic target for the treatment of AD.

Epigallocatechin-3-gallate protects Wharton's jelly derived mesenchymal stem cells against in vitro heat stress

The deteriorating effects of heat stress abrogate the therapeutic implications of human Wharton's jelly derived mesenchymal stem cells (hWJMSCs) transplanted in burn wounds. Topically applied green tea extract comprising epigallocatechin-3-gallate (EGCG) is known to repair burn wounds. Here, we investigated the protective role of EGCG priming of hWJMSCs against heat-induced stress in vitro along with the involved underlying mechanism. EGCG ameliorated heat-induced injuries as demonstrated by significantly improved cell morphology, viability, triggered cell migration and enhanced expression of heat shock proteins. In addition, decreased lactate dehydrogenase release and reduced percentage of senescent and apoptotic cells were observed. EGCG priming alleviated the detrimental effects of thermal stress in hWJMSCs as observed by significant down-regulation in expression of BCL2 associated X (BAX), interleukin 6 (IL6), and interleukin 1 beta (IL1β) genes, while proliferating cell nuclear antigen (PCNA), BCL2 like 1 (BCL2L1), vascular endothelial growth factor (VEGF), transforming growth factor beta 1 (TGFβ1), hepatocyte growth factor (HGF) and interleukin 4 (IL4) genes were up-regulated. Accompanying gene expression data, EGCG primed cells exposed to heat stress also exhibited remarkably increased secretion of VEGF, HGF, epidermal growth factor (EGF), stromal-derived factor 1 (SDF1) proteins while the reduced release of IL-6, and tumor necrosis factor-alpha (TNF-α) proteins. Further, synergistic activation of extracellular-signal-regulated kinase (ERK) and protein kinase B (PKB/AKT) proteins was observed. These findings suggest that EGCG priming might enhance the therapeutic efficacy of hWJMSCs in the burnt tissue through regulation of ERK and AKT signaling pathways, and improved cellular responses.

Modulation of Nerve Cell Differentiation: Role of Polyphenols and of Contactin Family Components

In this study the mechanisms are explored, which modulate expression and function of cell surface adhesive glycoproteins of the Immunoglobulin Supergene Family (IgSF), and in particular of its Contactin subset, during neuronal precursor developmental events. In this context, a specific topic concerns the significance of the expression profile of such molecules and their ability to modulate signaling pathways activated through nutraceuticals, in particular polyphenols, administration. Both in vitro and in vivo approaches are chosen. As for the former, by using as a model the human SH-SY5Y neuroblastoma line, the effects of grape seed polyphenols are evaluated on proliferation and commitment/differentiation events along the neuronal lineage. In SH-SY5Y cell cultures, polyphenols were found to counteract precursor proliferation while promoting their differentiation, as deduced by studying their developmental parameters through the expression of cell cycle and neuronal commitment/differentiation markers as well as by measuring neurite growth. In such cultures, Cyclin E expression and BrdU incorporation were downregulated, indicating reduced precursor proliferation while increased neuronal differentiation was inferred from upregulation of cell cycle exit (p27^–Kip) and neuronal commitment (NeuN) markers as well as by measuring neurite length through morphometric analysis. The polyphenol effects on developmental parameters were also explored in vivo, in cerebellar cortex, by using as a model the TAG/F3 transgenic line, which undergoes delayed neural development as a consequence of Contactin1 adhesive glycoprotein upregulation and premature expression under control of the Contactin2 gene (Cntn-2) promoter. In this transgenic line, a Notch pathway activation is known to occur and polyphenol treatment was found to counteract such an effect, demonstrated through downregulation of the Hes-1 transcription factor. Polyphenols also downregulated the expression of adhesive glycoproteins of the Contactin family themselves, demonstrated for both Contactin1 and Contactin2, indicating the involvement of changes in the expression of the underlying genes in the observed phenotype. These data support the hypothesis that the complex control exerted by polyphenols on neural development involves modulation of expression and function of the genes encoding cell adhesion molecules of the Contactin family and of the associated signaling pathways, indicating potential mechanisms whereby such compounds may control neurogenesis.

Spinal cord injury: pathophysiology, treatment strategies, associated challenges, and future implications

Axonal regeneration and formation of tripartite (axo-glial) junctions at damaged sites is a prerequisite for early repair of injured spinal cord. Transplantation of stem cells at such sites of damage which can generate both neuronal and glial population has gained impact in terms of recuperation upon infliction with spinal cord injury. In spite of the fact that a copious number of pre-clinical studies using different stem/progenitor cells have shown promising results at acute and subacute stages, at the chronic stages of injury their recovery rates have shown a drastic decline. Therefore, developing novel therapeutic strategies are the need of the hour in order to assuage secondary morbidity and effectuate improvement of the spinal cord injury (SCI)-afflicted patients' quality of life. The present review aims at providing an overview of the current treatment strategies and also gives an insight into the potential cell-based therapies for the treatment of SCI.

CNB-001 reduces paraplegia in rabbits following spinal cord ischemia

Spinal cord ischemia associated with trauma and surgical procedures including thoraco-abdominal aortic aneurysm repair and thoracic endovascular aortic repair results in devastating clinical deficits in patients. Because spinal cord ischemia is inadequately treated, we studied the effects of [4-((1E)-2-(5-(4-hydroxy-3-methoxystyryl-)-1-phenyl-1H-pyrazoyl-3-yl) vinyl)-2-methoxy-phenol)] (CNB-001), a novel curcumin-based compound, in a rabbit SCI model. CNB-001 is known to inhibit human 5-lipoxygenase and 15-lipoxygenase and reduce the ischemia-induced inflammatory response. Moreover, CNB-001 can reduce the level of oxidative stress markers and potentiate brain-derived neurotrophic factor and brain-derived neurotrophic factor receptor signaling. The Tarlov scale and quantal analysis technique results revealed that CNB-001 administered as an intravenous dose (bolus) 30 minutes prior to spinal cord ischemia improved the behaviors of female New Zealand White rabbits. The improvements were similar to those produced by the uncompetitive N-methyl-D-aspartate receptor antagonist memantine. At 48 hours after aortic occlusion, there was a 42.7% increase (P < 0.05) in tolerated ischemia duration (n = 14) for rabbits treated with CNB-001 (n = 16), and a 72.3% increase for rabbits treated with the positive control memantine (P < 0.05) (n = 23) compared to vehicle-treated ischemic rabbits (n = 22). CNB-001 is a potential important novel treatment for spinal cord ischemia induced by aortic occlusion. All experiments were approved by the CSMC Institutional Animal Care and Use Committee (IACUC #4311) on November 1, 2012.

A Novel Peroxidase Mimics and Ameliorates Alzheimer's Disease-Related Pathology and Cognitive Decline in Mice

Alzheimer's disease (AD) is the most common neurodegenerative disorder in the elderly, which is characterized by the accumulation of amyloid β (Aβ) plaques, oxidative stress, and neuronal loss. Therefore, clearing Aβ aggregates and reducing oxidative stress could be an effective therapeutic strategy for AD. Deuterohemin-AlaHisThrValGluLys (DhHP-6), a novel deuterohemin-containing peptide mimetic of the natural microperoxidase-11 (MP-11), shows higher antioxidant activity and stability compared to the natural microperoxidases. DhHP-6 possesses the ability of extending lifespan and alleviating paralysis in the Aβ1-42 transgenic Caenorhabditis elegans CL4176 model of AD, as shown in our previous study. Therefore, this study was aimed at exploring the neuroprotective effect of DhHP-6 in the APPswe/PSEN1dE9 transgenic mouse model of AD. DhHP-6 reduced the diameter and fiber structure of Aβ1-42 aggregation in vitro, as shown by dynamic light scattering and transmission electron microscope. DhHP-6 exerted its neuroprotective effect by inhibiting Aβ aggregation and plaque formation, and by reducing Aβ1-42 oligomers-induced neurotoxicity on HT22 (mouse hippocampal neuronal) and SH-SY5Y (human neuroblastoma) cells. In the AD mouse model, DhHP-6 significantly ameliorated cognitive decline and improved spatial learning ability in behavioral tests including the Morris water maze, Y-maze, novel object recognition, open field, and nest-building test. Moreover, DhHP-6 reduced the deposition of Aβ plaques in the cerebral cortex and hippocampus. More importantly, DhHP-6 restored the morphology of astrocytes and microglia, and significantly reduced the levels of pro-inflammatory cytokines. Our findings provide a basis for considering the non-toxic, peroxidase mimetic DhHP-6 as a new candidate drug against AD.

The transplantation of human urine stem cells combined with chondroitinase ABC promotes brain-derived neurotrophic factor and nerve growth factor following spinal cord injury in rats

Cells based on therapies are currently gaining momentum in neural tissue engineering to treat spinal cord injury (SCI). The present study aimed to evaluate the effects of the concomitant use of human urine stem cells (hUSCs) and chondroitinase ABC (ChABC) on functional improvement and to explore the expressions of brain-derived neurotrophic factor (BDNF) and nerve growth factor (NGF). The SCI model was induced by a falling heavy object. hUSCs were cultured and transplanted into the impaired spinal cord with ChABC administration. The Basso, Beattie and Bresnahan (BBB) scores were valued, and real time PCR, immunofluorescence and Western blot were used to detect the expression of BDNF and NGF. We found that rats receiving both hUSCs and ChABC treatment demonstrated the best functional recovery. In addition, the mRNA and protein expressions of the BDNF and NGF expressions were found to be effectively higher in the combined treatment group than these in the other groups. In conclusion, hUSCs transplantation combined with ChABC administration promotes motor functional recovery in SCI rats, which may be associated with BDNF and NGF regulation.