Curcumin Promotes Proliferation of Adult Neural Stem Cells and the Birth of Neurons in Alzheimer's Disease Mice via Notch Signaling Pathway

Delineation of the role of G6PD in Alzheimer's disease and potential enhancement through microfluidic and nanoparticle approaches

Alzheimer's disease (AD) is a neurodegenerative pathologic entity characterized by the abnormal presence of tau and macromolecular Aβ deposition that leads to the degeneration or death of neurons. In addition to that, glucose-6-phosphate dehydrogenase (G6PD) has a multifaceted role in the process of AD development, where it can be used as both a marker and a target. G6PD activity is dysregulated due to its contribution to oxidative stress, neuroinflammation, and neuronal death. In this context, the current review presents a vivid depiction of recent findings on the relationship between AD progression and changes in the expression or activity of G6PD. The efficacy of the proposed G6PD-based therapeutics has been demonstrated in multiple studies using AD mouse models as representative animal model systems for cognitive decline and neurodegeneration associated with this disease. Innovative therapeutic insights are made for the boosting of G6PD activity via novel innovative nanotechnology and microfluidics tools in drug administration technology. Such approaches provide innovative methods of surpassing the blood-brain barrier, targeting step-by-step specific neural pathways, and overcoming biochemical disturbances that accompany AD. Using different nanoparticles loaded with G6DP to target specific organs, e.g., G6DP-loaded liposomes, enhances BBB penetration and brain distribution of G6DP. Many nanoparticles, which are used for different purposes, are briefly discussed in the paper. Such methods to mimic BBB on organs on-chip offer precise disease modeling and drug testing using microfluidic chips, requiring lower sample amounts and producing faster findings compared to conventional techniques. There are other contributions to microfluid in AD that are discussed briefly. However, there are some limitations accompanying microfluidics that need to be worked on to be used for AD. This study aims to bridge the gap in understanding AD with the synergistic use of promising technologies; microfluid and nanotechnology for future advancements.

Therapeutic potential of curcumin on the cognitive decline in animal models of Alzheimer's disease: a systematic review and meta-analysis

Curcumin, a polyphenol derived from the herb turmeric, has emerged as a prospective potential therapy in the treatment of Alzheimer's disease (AD). However, the efficacy of curcumin treatment in improving cognitive decline caused controversy recently. We aimed to systematically review the effect of curcumin on cognitive impairment in an animal model of AD. We conducted an exhaustive database search of related studies. Two investigators identified studies and independently extracted data. Stratified meta-analyses and meta-regression analyses were carried out to explore the sources of heterogeneity. Publication bias was assessed using funnel plots and Egger's test. Our systematic review included 33 articles. A meta-analysis of 29 publications showed that curcumin exerts significant positive effects on cognitive performance. For acquisition, the global estimated effect of curcumin was - 2.027 (95% CI - 2.435 to - 1.619, p < 0.001); for retention, the global estimated effect of curcumin was 1.606 (95% CI 1.101 to 2.111, p < 0.001). The stratified meta-analysis demonstrated that an increased effect size depended on diverse study characteristics. Additionally, publication bias was detected. We conclude that curcumin may reduce cognitive deficits in experimental AD. Furthermore, we emphasize that additional well-designed and well-reported animal studies are needed to inform further clinical studies.

MicroRNA biomarkers as next-generation diagnostic tools for neurodegenerative diseases: a comprehensive review

Neurodegenerative diseases (NDs) are characterized by abnormalities within neurons of the brain or spinal cord that gradually lose function, eventually leading to cell death. Upon examination of affected tissue, pathological changes reveal a loss of synapses, misfolded proteins, and activation of immune cells-all indicative of disease progression-before severe clinical symptoms become apparent. Early detection of NDs is crucial for potentially administering targeted medications that may delay disease advancement. Given their complex pathophysiological features and diverse clinical symptoms, there is a pressing need for sensitive and effective diagnostic methods for NDs. Biomarkers such as microRNAs (miRNAs) have been identified as potential tools for detecting these diseases. We explore the pivotal role of miRNAs in the context of NDs, focusing on Alzheimer's disease, Parkinson's disease, Multiple sclerosis, Huntington's disease, and Amyotrophic Lateral Sclerosis. The review delves into the intricate relationship between aging and NDs, highlighting structural and functional alterations in the aging brain and their implications for disease development. It elucidates how miRNAs and RNA-binding proteins are implicated in the pathogenesis of NDs and underscores the importance of investigating their expression and function in aging. Significantly, miRNAs exert substantial influence on post-translational modifications (PTMs), impacting not just the nervous system but a wide array of tissues and cell types as well. Specific miRNAs have been found to target proteins involved in ubiquitination or de-ubiquitination processes, which play a significant role in regulating protein function and stability. We discuss the link between miRNA, PTM, and NDs. Additionally, the review discusses the significance of miRNAs as biomarkers for early disease detection, offering insights into diagnostic strategies.

Emerging Pro-neurogenic Therapeutic Strategies for Neurodegenerative Diseases: A Review of Pre-clinical and Clinical Research

The neuroscience community has largely accepted the notion that functional neurons can be generated from neural stem cells in the adult brain, especially in two brain regions: the subventricular zone of the lateral ventricles and the subgranular zone in the dentate gyrus of the hippocampus. However, impaired neurogenesis has been observed in some neurodegenerative diseases, particularly in Alzheimer's, Parkinson's, and Huntington's diseases, and also in Lewy Body dementia. Therefore, restoration of neurogenic function in neurodegenerative diseases emerges as a potential therapeutic strategy to counteract, or at least delay, disease progression. Considering this, the present study summarizes the different neuronal niches, provides a collection of the therapeutic potential of different pro-neurogenic strategies in pre-clinical and clinical research, providing details about their possible modes of action, to guide future research and clinical practice.

Curcumin Improves Neurogenesis in Alzheimer's Disease Mice via the Upregulation of Wnt/β-Catenin and BDNF

Adult neurogenesis in the dentate gyrus (DG) is impaired during Alzheimer's disease (AD) progression. Curcumin has been reported to reduce cell apoptosis and stimulate neurogenesis. This study aimed to investigate the influence of curcumin on adult neurogenesis in AD mice and its potential mechanism. Two-month-old male C57BL/6J mice were injected with soluble β-amyloid (Aβ1-42) using lateral ventricle stereolocalization to establish AD models. An immunofluorescence assay, including bromodeoxyuridine (BrdU), doublecortin (DCX), and neuron-specific nuclear antigen (NeuN), was used to detect hippocampal neurogenesis. Western blot and an enzyme-linked immunosorbent assay (ELISA) were used to test the expression of related proteins and the secretion of brain-derived neurotrophic factor (BDNF). A Morris water maze was used to detect the cognitive function of the mice. Our results showed that curcumin administration (100 mg/kg) rescued the impaired neurogenesis of Aβ1-42 mice, shown as enhanced BrdU+/DCX+ and BrdU+/NeuN+ cells in DG. In addition, curcumin regulated the phosphatidylinositol 3 kinase (PI3K)/protein kinase B (Akt) -mediated glycogen synthase kinase-3β (GSK3β) /Wingless/Integrated (Wnt)/β-catenin pathway and cyclic adenosine monophosphate response element-binding protein (CREB)/BDNF in Aβ1-42 mice. Inhibiting Wnt/β-catenin and depriving BDNF could reverse both the upregulated neurogenesis and cognitive function of curcumin-treated Aβ1-42 mice. In conclusion, our study indicates that curcumin, through targeting PI3K/Akt, regulates GSK3β/Wnt/β-catenin and CREB/BDNF pathways, improving the adult neurogenesis of AD mice.

Adult neurogenesis: a real hope or a delusion?

Adult neurogenesis, the process of creating new neurons, involves the coordinated division, migration, and differentiation of neural stem cells. This process is restricted to neurogenic niches located in two distinct areas of the brain: the subgranular zone of the dentate gyrus of the hippocampus and the subventricular zone of the lateral ventricle, where new neurons are generated and then migrate to the olfactory bulb. Neurogenesis has been thought to occur only during the embryonic and early postnatal stages and to decline with age due to a continuous depletion of neural stem cells. Interestingly, recent years have seen tremendous progress in our understanding of adult brain neurogenesis, bridging the knowledge gap between embryonic and adult neurogenesis. Here, we discuss the current status of adult brain neurogenesis in light of what we know about neural stem cells. In this notion, we talk about the importance of intracellular signaling molecules in mobilizing endogenous neural stem cell proliferation. Based on the current understanding, we can declare that these molecules play a role in targeting neurogenesis in the mature brain. However, to achieve this goal, we need to avoid the undesired proliferation of neural stem cells by controlling the necessary checkpoints, which can lead to tumorigenesis and prove to be a curse instead of a blessing or hope.

Curcumin alleviates Alzheimer's disease by inhibiting inflammatory response, oxidative stress and activating the AMPK pathway

BACKGROUND

Alzheimer's disease (AD) is a common degenerative brain disorder with limited therapeutic options. Curcumin (Cur) exhibits neuroprotective function in many diseases. We aimed to explore the role and mechanism of Cur in AD.

MATERIALS AND METHODS

Firstly, we established AD mice by injecting amyloid-β1-42 (Aβ1-42) solution into the hippocampus. Then, the AD mice received 150 mg/kg/d Cur for 10 consecutive days. The Morris water maze test was conducted to evaluate the cognitive function of the mice by hidden platform training and probe trials. To assess the spatial memory of the mice, spontaneous alternation behavior, the number of crossing the novel arm and the time spent in the novel arm during the Y-maze test was recorded. Hematoxylin and eosin (H&E) staining and terminal deoxynucleotidyl transferase-mediated dUTP nick end labeling (TUNAL) assay were performed to assess the pathological damage and apoptosis of brain tissues. The number of damaged neurons was inspected by Nissl staining. Immunohistochemical staining was then performed to detect Aβ1-42 deposition. The levels of tumor necrosis factor-α (TNF-a), interleukin-6 (IL-6) and interleukin-1β (IL-1β) in serum and hippocampus, the contents of super oxide dismutase (SOD) and malondialdehyde (MDA) in brain tissues were assessed by enzyme-linked immunosorbent assay (ELISA). Additionally, B-cell lymphoma-2 (Bcl-2), Bcl-2 associated X protein (Bax), RelA (p65) protein expressions and Adenosine 5'-monophosphate-activated protein kinase (AMPK) phosphorylation were tested using Western blot.

RESULTS

Cur not only improved cognitive function and spatial memory, but also alleviated the pathological damage and apoptosis of brain tissues for AD mice. Meanwhile, upon Cur treatment, the number of damaged neurons in AD mice was decreased, the level of Aβ1-42 in AD mice was significantly decreased. Furthermore, the AD mice treated with Cur exhibited lower TNF-a, IL-6, IL-1β and MDA levels and a higher SOD content. Besides, Cur also downregulated p65 expression and upregulated AMPK phosphorylation.

CONCLUSION

Cur may improve AD via suppressing the inflammatory response, oxidative stress and activating the AMPK pathway, suggesting that Cur may be a potential drug for AD.

Quercetin-3-O-β-d-glucuronide in the Nuciferine Leaf Polyphenol Extract Promotes Neurogenesis Involving the Upregulation of the Tropomyosin Receptor Kinase (Trk) Receptor and AKT/Phosphoinositide 3-Kinase Signaling Pathway

Neurogenesis is crucial during the human lifespan for the maintenance of synaptic plasticity and normal function. The impairment of hippocampal neurogenesis in adults may lead to neurodegenerative disease, such as Alzheimer's disease. Miquelianin (quercetin-3-O-β-d-glucuronide, Q3GA) is a constituent of the nuciferine leaf polyphenol extract (NLPE), and it has protective effects against neurodegeneration. In this study, we examined the effect of the NLPE on neurogenesis and the mechanisms underlying Q3GA on neurogenesis. We fed 24-week-old male C57BL/6 mice with 0.1 or 0.25% NLPE for 2 weeks. NLPE treatment increased small spindle-shaped stem cell numbers in the subgranular zone and the number of doublecortin (DCX)- and neuron-specific nuclear protein (NeuN)-expressing neurons. HT22, a hippocampal cell line, treated with Q3GA revealed significant neurite growth and upregulated TrkR and PI3K/Akt levels. The evidence from a model of retinoic acid-induced SH-SY5Y cell differentiation showed that Q3GA or NLPE increases neurite growth significantly. Taken together, the NLPE containing Q3GA to promote neurogenesis involving the upregulation of TrkR and the PI3K/Akt signaling pathway might be potentiated as an alternative strategy for the treatment of neurodegeneration.

Role of curcumin and its nanoformulations in the treatment of neurological diseases through the effects on stem cells

Curcumin from turmeric is a natural phenolic compound with a promising potential to regulate fundamental processes involved in neurological diseases, including inflammation, oxidative stress, protein aggregation, and apoptosis at the molecular level. In this regard, employing nanoformulation can improve curcumin efficiency by reducing its limitations, such as low bioavailability. Besides curcumin, growing data suggest that stem cells are a noteworthy candidate for neurodegenerative disorders therapy due to their anti-inflammatory, anti-oxidative, and neuronal-differentiation properties, which result in neuroprotection. Curcumin and stem cells have similar neurogenic features and can be co-administered in a cell-drug delivery system to achieve better combination therapeutic outcomes for neurological diseases. Based on the evidence, curcumin can induce the neuroprotective activity of stem cells by modulating their related signalling pathways. The present review is about the role of curcumin and its nanoformulations in the improvement of neurological diseases alone and through the effect on different categories of stem cells by discussing the underlying mechanisms to provide a roadmap for future investigations.

Gut brain interaction theory reveals gut microbiota mediated neurogenesis and traditional Chinese medicine research strategies

Adult neurogenesis is the process of differentiation of neural stem cells (NSCs) into neurons and glial cells in certain areas of the adult brain. Defects in neurogenesis can lead to neurodegenerative diseases, mental disorders, and other maladies. This process is directionally regulated by transcription factors, the Wnt and Notch pathway, the extracellular matrix, and various growth factors. External factors like stress, physical exercise, diet, medications, etc., affect neurogenesis and the gut microbiota. The gut microbiota may affect NSCs through vagal, immune and chemical pathways, and other pathways. Traditional Chinese medicine (TCM) has been proven to affect NSCs proliferation and differentiation and can regulate the abundance and metabolites produced by intestinal microorganisms. However, the underlying mechanisms by which these factors regulate neurogenesis through the gut microbiota are not fully understood. In this review, we describe the recent evidence on the role of the gut microbiota in neurogenesis. Moreover, we hypothesize on the characteristics of the microbiota-gut-brain axis based on bacterial phyla, including microbiota's metabolites, and neuronal and immune pathways while providing an outlook on TCM's potential effects on adult neurogenesis by regulating gut microbiota.

Natural Product-based Nanomedicine: Recent Advances and Issues for the Treatment of Alzheimer's Disease

Alzheimer's disease (AD) affects the elderly and is characterized by progressive neurodegeneration caused by different pathologies. The most significant challenges in treating AD include the inability of medications to reach the brain because of its poor solubility, low bioavailability, and the presence of the blood-brain barrier (BBB). Additionally, current evidence suggests the disruption of BBB plays an important role in the pathogenesis of AD. One of the critical challenges in treating AD is the ineffective treatments and their severe adverse effects. Nanotechnology offers an alternative approach to facilitate the treatment of AD by overcoming the challenges in drug transport across the BBB. Various nanoparticles (NP) loaded with natural products were reported to aid in drug delivery for the treatment of AD. The nano-sized entities of NP are great platforms for incorporating active materials from natural products into formulations that can be delivered effectively to the intended action site without compromising the material's bioactivity. The review highlights the applications of medicinal plants, their derived components, and various nanomedicinebased approaches for the treatment of AD. The combination of medicinal plants and nanotechnology may lead to new theragnostic solutions for the treatment of AD in the future.

A Potential Strategy for Treatment of Neurodegenerative Disorders by Regulation of Adult Hippocampal Neurogenesis in Human Brain

Abstract:

Adult hippocampal neurogenesis is a multistage mechanism that continues throughout the lifespan of human and non-human mammals. These adult-born neurons in the central nervous system (CNS) play a significant role in various hippocampus-dependent processes, including learning, mood regulation, pattern recognition, etc. Reduction of adult hippocampal neurogenesis, caused by multiple factors such as neurological disorders and aging, would impair neuronal proliferation and differentiation and result in memory loss. Accumulating studies have indicated that functional neuron impairment could be restored by promoting adult hippocampal neurogenesis. In this review, we summarized the small molecules that could efficiently promote the process of adult neurogenesis, particularly the agents that have the capacity of crossing the blood-brain barrier (BBB), and showed in vivo efficacy in mammalian brains. This may pave the way for the rational design of drugs to treat humnan neurodegenerative disorders in the future.

Therapeutic role of curcumin in adult neurogenesis for management of psychiatric and neurological disorders: a scientometric study to an in-depth review

Aberrant neurogenesis is a major factor in psychiatric and neurological disorders that have significantly attracted the attention of neuroscientists. Curcumin is a primary constituent of curcuminoid that exerts several positive pharmacological effects on aberrant neurogenesis. First, it is important to understand the different processes of neurogenesis, and whether their dysfunction promotes etiology as well as the development of many psychiatric and neurological disorders; then investigate mechanisms by which curcumin affects neurogenesis as an active participant in pathophysiological events. Based on scientometric studies and additional extensive research, we explore the mechanisms by which curcumin regulates adult neurogenesis and in turn affects psychiatric diseases, i.e., depression and neurological disorders among them traumatic brain injury (TBI), stroke, Alzheimer's disease (AD), Gulf War Illness (GWI) and Fragile X syndrome (FXS). This review aims to elucidate the therapeutic effects and mechanisms of curcumin on adult neurogenesis in various psychiatric and neurological disorders. Specifically, we discuss the regulatory role of curcumin in different activities of neural stem cells (NSCs), including proliferation, differentiation, and migration of NSCs. This is geared toward providing novel application prospects of curcumin in treating psychiatric and neurological disorders by regulating adult neurogenesis.

Applications of Phyto-Nanotechnology for the Treatment of Neurodegenerative Disorders

The strategies involved in the development of therapeutics for neurodegenerative disorders are very complex and challenging due to the existence of the blood-brain barrier (BBB), a closely spaced network of blood vessels and endothelial cells that functions to prevent the entry of unwanted substances in the brain. The emergence and advancement of nanotechnology shows favourable prospects to overcome this phenomenon. Engineered nanoparticles conjugated with drug moieties and imaging agents that have dimensions between 1 and 100 nm could potentially be used to ensure enhanced efficacy, cellular uptake, specific transport, and delivery of specific molecules to the brain, owing to their modified physico-chemical features. The conjugates of nanoparticles and medicinal plants, or their components known as nano phytomedicine, have been gaining significance lately in the development of novel neuro-therapeutics owing to their natural abundance, promising targeted delivery to the brain, and lesser potential to show adverse effects. In the present review, the promising application, and recent trends of combined nanotechnology and phytomedicine for the treatment of neurological disorders (ND) as compared to conventional therapies, have been addressed. Nanotechnology-based efforts performed in bioinformatics for early diagnosis as well as futuristic precision medicine in ND have also been discussed in the context of computational approach.

Naproxen as a potential candidate for promoting rivastigmine anti-Alzheimer activity against aluminum chloride-prompted Alzheimer's-like disease in rats; neurogenesis and apoptosis modulation as a possible underlying mechanism

BACKGROUND AND AIM

Alzheimer's disease (AD) is one of the leading causes of dependence and disability among the elderly worldwide. The traditional anti-Alzheimer medication, rivastigmine, one of the cholinesterase inhibitors (ChEIs), fails to achieve a definitive cure. We tested the hypothesis that naproxen administration to the rivastigmine-treated aluminum chloride (AlCl3) Alzheimer's rat model could provide an additive neuroprotective effect compared to rivastigmine alone.

MATERIALS AND METHODS

The studied groups were control (Cont), AlCl3 treated (Al), rivastigmine treated (RIVA), naproxen treated (Napro), and combined rivastigmine and naproxen treated (RIVA + Napro). Rats' memory, spatial learning, and cognitive behavior were assessed followed by evaluation of hippocampal acetylcholinesterase (AChE) activity. Hippocampal and cerebellar histopathology were thoroughly examined. Activated caspase-3 and the neuroepithelial stem cells marker; nestin expressions were immunohistochemically assayed.

RESULTS

AD rats displayed significantly impaired memory and cognitive function, augmented hippocampal AChE activity; massive neurodegeneration associated with enhanced astrogliosis, apoptosis, and impaired neurogenesis. Except for the enhancement of neurogenesis and suppression of apoptosis, the combination therapy had no additional neuroprotective benefit over rivastigmine-only therapy.

CONCLUSION

Naproxen's efficacy was established by its ability to function at the cellular level, improved neurogenesis, and decreased, apoptosis without having an additional mitigating impact on cognitive impairment in rivastigmine-treated AD rats.

In vitro differentiation of human bone marrow stromal cells into neural precursor cells using small molecules

BACKGROUND

Neurogenic differentiation of human marrow stromal stem cells (hMSCs) into neural precursor cells (NPCs) offers new hope in many neurological diseases. Stromal cells can be differentiated into NPCs using small molecules acting as chemical inducers. The aim of this study is to formulate an efficient, direct, fast and safe protocol to differentiate hMSCs into NPCs using different inducers: b-mercaptoethanol (BME), triiodothyronine (T3), and curcumin (CUR). NEW METHOD: hMSCs were subjected to either 1 mM BME, 0.5 µM T3, or 5 µM CUR. Neurogenic differentiation was determined by assessing the protein expression of PAX6, SOX2, DLX2, and GAP-43 with flow cytometry and immunofluorescence, along with Nissl staining of differentiated cells.

RESULTS AND COMPARISON WITH EXISTING METHOD

It was revealed that T3 and CUR are 70-80% better than BME in terms of efficiency and safety, and surprisingly BME was a good promoting factor for cell preconditioning with limited effects on neural trans-differentiation related to its toxic effects on cell viability.

CONCLUSION

Reprogramming of bone marrow stromal cells into neural cells gives hope for treating different neurological disorders. Our study shows that T3 and CUR were effective in generation of NPCs from hMSCs with preservation of cell viability. BME was a good promoting factor for cell preconditioning with limited effects on neural transdifferentiation related to its toxic effects on cell viability.

The Effects and Regulative Mechanism of Scutellaria Baicalensis Georgi Stems and Leaves Flavonoids in Promoting Neurogenesis and Improving Memory Impairment Mediated by BDNF-ERK-CREB Signal Pathway in Rats

BACKGROUND

It is well known that Alzheimer's disease (AD) is a degenerative disease, and accompanied by memory impairment and main pathological changes of the extracellular senile plaque (SP) and intracellular neurofibrillary tangles (NFTs). However, there are many evidences showing that the disorders of neurogenesis are also regarded as a new opinion in AD.

OBJECTIVE

To investigate the effects and regulative mechanism of Scutellaria baicalensis Georgi stems and leaves flavonoids in promoting neurogenesis and improving memory impairment mediated by BDNF-ERK-CREB signal pathway in rats.

METHODS

Male Wistar rats were intracerebroventricularly injected with amyloid-beta protein 25-35 (Aβ25-35) in combination with aluminum trichloride (AlCl3) and recombinant human transforming growth factor-β1 (RHTGF-β1) (composited Aβ), to establish an AD model. Morris water maze was used to screen AD model of rats and measure the rats' learning and memory ability. The expression of cell neurogenesis related molecule Ki67 protein in the hippocampal gyrus of rats was detected by the immunohistochemical method. The expression of mRNA and protein of Grb2, SOS1, Ras, ERK and BDNF in the BDNF-ERK-CREB signaling pathway, in the hippocampus and cerebral cortex were assayed by the Quantitative real-time PCR (qPCR) and Western blotting methods, respectively.

RESULTS

Intracerebroventricular injection of composited Aβ could produce the rats' memory impairment, decrease the protein expression of Ki67 in the hippocampal gyrus, and increase the mRNA and protein expression levels of Grb2, SOS1, Ras, ERK and BDNF in the hippocampus and cerebral cortex. However, SSF could significantly ameliorate the rats' memory impairment, lower the reduction of Ki67 protein expression in the hippocampal gyrus and regulate the mRNA and protein expression abnormal levels of Grb2, SOS1, Ras, ERK and BDNF in the hippocampus and cerebral cortex induced by composited Aβ.

CONCLUSION

Composited Aβ can result in memory impairment, decrease neurogenesis and regulate the mRNA and protein abnormal expression of Grb2, SOS1, Ras, ERK and BDNF in BDNF-ERK-CREB signaling pathway. The effects of SSF in promoting neurogenesis and improving memory impairment may be related to the regulation in Grb2, SOS1, Ras, ERK and BDNF molecules' expression of the BDNF-ERK-CREB signaling pathway.

Peptide KED: Molecular-Genetic Aspects of Neurogenesis Regulation in Alzheimer's Disease

Neuroprotective peptides are promising candidate molecules for the treatment of Alzheimer's disease (AD). Oral application of KED (Lys-Glu-Asp) improved memory and attention in elderly individuals with functional CNS disorders. Peptide KED also restores synaptic plasticity in in vitro model of AD. This review is focused on the analysis of the influence of KED peptide on the expression of genes and synthesis of proteins regulating apoptosis, aging, neurogenesis, and involved in AD pathogenesis. Analysis of published reports and our experimental findings suggests that KED regulates the expression of genes of cell aging and apoptosis (р16, р21), genes (NES, GAP43) and proteins (nestin, GAP43) of the neuronal differentiation, and genes involved in AD pathogenesis (SUMO, APOE, and IGF1). The study the effectiveness of neuroprotective peptide KED in animal models of AD seems to be very important.

Action Mechanisms of Curcumin in Alzheimer's Disease and Its Brain Targeted Delivery

AD is a chronic neurodegenerative disease. Many different signaling pathways, such as Wnt/β-catenin, Notch, ROS/JNK, and PI3K/Akt/mTOR are involved in Alzheimer’s disease and crosstalk between themselves. A promising treatment involves the uses of flavonoids, and one of the most promising is curcumin; however, because it has difficulty permeating the blood–brain barrier (BBB), it must be encapsulated by a drug carrier. Some of the most frequently studied are lipid nanocarriers, liposomes, micelles and PLGA. These carriers are further conjugated with brain-targeting agents such as lactoferrin and transferrin. In this review paper, curcumin and its therapeutic effects, which have been examined in vivo, are analyzed and then the delivery systems to the brain are addressed. Overall, the analysis of the literature revealed great potential for curcumin in treating AD and indicated the challenges that require further research.

Curcuminoid-Tailored Interfacial Free Energy of Hydrophobic Fibers for Enhanced Biological Properties

The ability of mimicking the extracellular matrix architecture has gained electrospun scaffolds a prominent space into the tissue engineering field. The high surface-to-volume aspect ratio of nanofibers increases their bioactivity while enhancing the bonding strength with the host tissue. Over the years, numerous polyesters, such as poly(lactic acid) (PLA), have been consolidated as excellent matrices for biomedical applications. However, this class of polymers usually has a high hydrophobic character, which limits cell attachment and proliferation, and therefore decreases biological interactions. In this way, functionalization of polyester-based materials is often performed in order to modify their interfacial free energy and achieve more hydrophilic surfaces. Herein, we report the preparation, characterization, and in vitro assessment of electrospun PLA fibers with low contents (0.1 wt %) of different curcuminoids featuring π-conjugated systems, and a central β-diketone unit, including curcumin itself. We evaluated the potential of these materials for photochemical and biomedical purposes. For this, we investigated their optical properties, water contact angle, and surface features while assessing their in vitro behavior using SH-SY5Y cells. Our results demonstrate the successful generation of homogeneous and defect-free fluorescent fibers, which are noncytotoxic, exhibit enhanced hydrophilicity, and as such greater cell adhesion and proliferation toward neuroblastoma cells. The unexpected tailoring of the scaffolds' interfacial free energy has been associated with the strong interactions between the PLA hydrophobic sites and the nonpolar groups from curcuminoids, which indicate its role for releasing hydrophilic sites from both parts. This investigation reveals a straightforward approach to produce photoluminescent 3D-scaffolds with enhanced biological properties by using a polymer that is essentially hydrophobic combined with the low contents of photoactive and multifunctional curcuminoids.

Mechanisms of oxidative stress in methylmercury-induced neurodevelopmental toxicity

Methylmercury (MeHg) is a long-lasting organic environmental pollutant that poses a great threat to human health. Ingestion of seafood containing MeHg is the most important way by which it comes into contact with human body, where the central nervous system (CNS) is the primary target of MeHg toxicity. During periods of pre-plus postnatal, in particular, the brain of offspring is vulnerable to specific developmental insults that result in abnormal neurobehavioral development, even without symptoms in mothers. While many studies on neurotoxic effects of MeHg on the developing brain have been conducted, the mechanisms of oxidative stress in MeHg-induced neurodevelopmental toxicity is less clear. Hitherto, no single process can explain the many effects observed in MeHg-induced neurodevelopmental toxicity. This review summarizes the possible mechanisms of oxidative stress in MeHg-induced neurodevelopmental toxicity, highlighting modulation of Nrf2/Keap1/Notch1, PI3K/AKT, and PKC/MAPK molecular pathways as well as some preventive drugs, and thus contributes to the discovery of endogenous and exogenous molecules that can counteract MeHg-induced neurodevelopmental toxicity.

The Act of Controlling Adult Stem Cell Dynamics: Insights from Animal Models

Adult stem cells (ASCs) are the undifferentiated cells that possess self-renewal and differentiation abilities. They are present in all major organ systems of the body and are uniquely reserved there during development for tissue maintenance during homeostasis, injury, and infection. They do so by promptly modulating the dynamics of proliferation, differentiation, survival, and migration. Any imbalance in these processes may result in regeneration failure or developing cancer. Hence, the dynamics of these various behaviors of ASCs need to always be precisely controlled. Several genetic and epigenetic factors have been demonstrated to be involved in tightly regulating the proliferation, differentiation, and self-renewal of ASCs. Understanding these mechanisms is of great importance, given the role of stem cells in regenerative medicine. Investigations on various animal models have played a significant part in enriching our knowledge and giving In Vivo in-sight into such ASCs regulatory mechanisms. In this review, we have discussed the recent In Vivo studies demonstrating the role of various genetic factors in regulating dynamics of different ASCs viz. intestinal stem cells (ISCs), neural stem cells (NSCs), hematopoietic stem cells (HSCs), and epidermal stem cells (Ep-SCs).

Activation of the Notch signaling pathway in the anterior cingulate cortex is involved in the pathological process of neuropathic pain

Plastic changes in the anterior cingulate cortex (ACC) are critical in pain hypersensitivity caused by peripheral nerves injury. The Notch signaling pathway has been shown to regulate synaptic differentiation and transmission. Therefore, this study was to investigate the function of the Notch signaling pathway in the ACC during nociceptive transmission induced by neuropathic pain. We adopted Western blotting, N-[N-(3,5-difluorophenacetyl)-l-alanyl]-S-phenylglycine t-butyl ester (DAPT) microinjections, RNA interference targeting Notch1, Hairy and enhancer of split (Hes) 1 or Hes5, electrophysiological recordings, and behavioral tests to verify the link between Notch signaling in ACC and neuropathic pain with adult male Sprague-Dawley rats. Levels of the Notch intracellular domain were increased in ACC on day 7 after chronic constriction injury surgery or spared nerve injury. Meanwhile, the mRNA level of the downstream effector of Notch signaling Hes1 was increased, whereas the level of Hes5 mRNA did not change. Microinjection of DAPT, a γ-secretase (a key enzyme involved in Notch pathway) inhibitor, into ACC significantly reversed neuropathic pain behaviors. Intra-ACC injection of short hairpin RNA-Notch reduced Notch intracellular domain expression and decreased the potentiation of synaptic transmission in the ACC. Moreover, pain perceptions were also alleviated in rats subjected to chronic constriction injury or spared nerve injury. This process was mainly mediated by the downstream effector Hes1, but not Hes5. Based on these results, the activation of the Notch/Hes1 signaling pathway in the ACC participates in the development of neuropathic pain, indicating that the Notch pathway may be a new therapeutic target for treating chronic pain.

Curcumin promotes neurogenesis of hippocampal dentate gyrus via Wnt/β-catenin signal pathway following cerebral ischemia in mice

OBJECTIVES

To investigate whether curcumin promotes hippocampal neurogenesis in the cerebral ischemia (CI) mice via Wnt/β-catenin signaling pathway.

METHODS

Male C57BL/6 mice were randomly divided into groups: sham operation group (Sham), cerebral ischemic group (CI), curcumin treatment group (50, 100 mg/kg/d, i.p.) and curcumin (100 mg/kg/d) + DKK1 (a blocker of Wnt receptor, 200 ng/d, icv) group. CI was induced by bilateral common carotid arteries occlusion (BCCAO) for 20 min. The Morris water maze test was conducted to detect spatial learning and memory. Immunofluorescence staining was used to examine the proliferation and differentiation of immature neurons in the hippocampal dentate gyrus. The proteins involved in neurogenesis and Wnt signaling pathway were examined using Western blot assay.

RESULTS

Curcumin significantly alleviated cognitive deficits induced by CI. Curcumin dose-dependently increased the proliferation of neural stem cells and promoted the differentiation and maturation of newly generated neural cells into neurons. Curcumin also increased the expression of proteins involved in neurogenesis (including Ngn2, Pax6 and NeuroD 1) and the Wnt/β-catenin signaling pathway. Moreover, the forenamed effects of curcumin were abolished by pretreatment with DKK1, a blocker of Wnt receptor.

CONCLUSION

Curcumin promotes hippocampal neurogenesis by activating Wnt/β-catenin signaling pathway to ameliorate cognitive deficits after acute CI.

Notch pathway up-regulation via curcumin mitigates bisphenol-A (BPA) induced alterations in hippocampal oligodendrogenesis

CNS myelination process involves proliferation and differentiation of oligodendrocyte progenitor cells (OPCs). Defective myelination causes onset of neurological disorders. Bisphenol-A (BPA), a component of plastic items, exerts adverse effects on human health. Our previous studies indicated that BPA impairs neurogenesis and myelination process stimulating cognitive dysfunctions. But, the underlying mechanism(s) of BPA induced de-myelination and probable neuroprotection by curcumin remains elusive. We found that curcumin protected BPA mediated adverse effects on oligosphere growth kinetics. Curcumin significantly improved proliferation and differentiation of OPCs upon BPA exposure both in-vitro and in-vivo. Curcumin enhanced the mRNA expression and protein levels of myelination markers in BPA treated rat hippocampus. Curcumin improved myelination potential via increasing β-III tubulin-/MBP⁺ cells (neuron-oligodendrocyte co-culture) and augmented fluoromyelin intensity and neurofilament/MBP⁺ neurons in vivo. In silico docking studies suggested Notch pathway genes (Notch-1, Hes-1 and Mib-1) as potential targets of BPA and curcumin. Curcumin reversed BPA mediated myelination inhibition via increasing the Notch pathway gene expression. Genetic and pharmacological Notch pathway inhibition by DAPT and Notch-1 siRNA exhibited decreased curcumin mediated neuroprotection. Curcumin improved BPA mediated myelin sheath degeneration and neurobehavioral impairments. Altogether, results suggest that curcumin protected BPA induced de-myelination and behavioural deficits through Notch pathway activation.

Low-intensity pulsed ultrasound regulates proliferation and differentiation of neural stem cells through notch signaling pathway

Low-intensity pulsed ultrasound (LIPUS) is widely used to regulate stem cell proliferation and differentiation. However, the effect of LIPUS stimulation on neural stem cells (NSCs) is not well documented. In this study, we have identified the optimal parameters, and investigated the cellular mechanisms of LIPUS to regulate the proliferation and differentiation of NSCs in vitro. NSCs were obtained and identified by nestin immunostaining. The proliferation of NSCs were measured by using Cell Counting Kit-8 (CCK-8). The expressions of nutritional factors (NTFs) were detected with immunoassay (ELISA). NSCs differentiation were detected by immunofluorescence and immunoblotting analysis. The expression level of proteins involved in the Notch signaling pathway was also measured by immunoblotting assay. Our results showed the intensity of 69.3 mW/cm² (1 MHz, 8 V) was applicable for LIPUS stimulation. ELISA analysis demonstrated that LIPUS treatment promoted the expression of nutritional factors of NSCs in vitro. Immunofluorescence and immunoblotting analyses suggested that the LIPUS not only reduced the astrocyte differentiation, but also stimulated the differentiation to neurons. Additionally, LIPUS stimulation significantly upregulated expression level of Notch1 and Hes1. Results from our study suggest that LIPUS triggers NSCs proliferation and differentiation by modulating the Notch signaling pathway. This study implies LIPUS as a potential and promising therapeutic platform for the optimization of stem cells and enable noninvasive neuromodulation for central nervous system diseases.

Therapeutic Study of Phytochemicals Against Cancer and Alzheimer's Disease Management

BACKGROUND

Phytochemicals are a significant piece of conventional prescription and have been researched in detail for conceivable consideration in current drug discovery. Medications and plants are firmly identified for traditional prescriptions and ethnomedicines that are basically arranged from plants. Recognizing the medical advantages of phytochemicals is of fundamental advancement in medication and useful sustenance improvement. Secondary metabolites of different plants have been customarily used for the improvement of human wellbeing. The phytochemicals are diets rich, which can upgrade neuroplasticity and protection from neurodegeneration.

RESULTS

Phytochemicals keep on entering clinical preliminaries or provide leads for the synthesis of medicinal agents. Phytochemicals are a great extent cancer prevention agents in nature at lower concentrations and under favorable cell conditions that adequately avoid the oxidation of different molecules that have an ability to produce free radicals and thus protect the body.

CONCLUSION

The purpose of this review is to describe the use of phytochemicals against cancer and Alzheimer's disease treatment.

Regulation and Directing Stem Cell Fate by Tissue Engineering Functional Microenvironments: Scaffold Physical and Chemical Cues

It is well known that stem cells reside within tissue engineering functional microenvironments that physically localize them and direct their stem cell fate. Recent efforts in the development of more complex and engineered scaffold technologies, together with new understanding of stem cell behavior in vitro, have provided a new impetus to study regulation and directing stem cell fate. A variety of tissue engineering technologies have been developed to regulate the fate of stem cells. Traditional methods to change the fate of stem cells are adding growth factors or some signaling pathways. In recent years, many studies have revealed that the geometrical microenvironment played an essential role in regulating the fate of stem cells, and the physical factors of scaffolds including mechanical properties, pore sizes, porosity, surface stiffness, three-dimensional structures, and mechanical stimulation may affect the fate of stem cells. Chemical factors such as cell-adhesive ligands and exogenous growth factors would also regulate the fate of stem cells. Understanding how these physical and chemical cues affect the fate of stem cells is essential for building more complex and controlled scaffolds for directing stem cell fate.