A novel natural product inspired scaffold with robust neurotrophic, neurogenic and neuroprotective action

Neurotrophic Natural Products

Neurotrophins (NGF, BDNF, NT3, NT4) can decrease cell death, induce differentiation, as well as sustain the structure and function of neurons, which make them promising therapeutic agents for the treatment of neurodegenerative disorders. However, neurotrophins have not been very effective in clinical trials mostly because they cannot pass through the blood-brain barrier owing to being high-molecular-weight proteins. Thus, neurotrophin-mimic small molecules, which stimulate the synthesis of endogenous neurotrophins or enhance neurotrophic actions, may serve as promising alternatives to neurotrophins. Small-molecular-weight natural products, which have been used in dietary functional foods or in traditional medicines over the course of human history, have a great potential for the development of new therapeutic agents against neurodegenerative diseases such as Alzheimer's disease. In this contribution, a variety of natural products possessing neurotrophic properties such as neurogenesis, neurite outgrowth promotion (neuritogenesis), and neuroprotection are described, and a focus is made on the chemistry and biology of several neurotrophic natural products.

Potential of Zinc Oxide-Graphene Quantum Dots and Zinc Oxide-Nitrogen-Doped Graphene Quantum Dot Nanocomposites as Neurotrophic Agents

Over the past few decades, zinc oxide nanoparticles have also proven to be essential to a variety of scientific research sectors, including antimicrobial therapy, tissue engineering, bioimaging, biosensors, drug delivery, gene delivery, and bioimaging. There is an urgent need to establish and develop unique alternative treatment modalities to treat neurodegenerative disorders due to the shortcomings of the existing drugs. As a possible therapy for brain diseases and disorders, the ability of the nanoparticles to cross the blood-brain barrier (BBB) as well as their reduced toxicity, solubility, and biodegradability has lately attracted attention. Scientists are quietly turning their attention to develop green synthesis of nanoparticles as an alternative to the physical and chemical techniques of producing the same. Existing literature has emphasized the use of ZnO for the potential treatment of cerebral ischemia and its neuroprotective properties. This work discusses the potential of ZnO prepared using Gynura cusimba extract and its nanocomposites with graphene quantum dots (GQDs) and its nitrogen doped variant, N-GQDs as neurotrophic agents, in accordance with our previous report on the use of GQDs and N-GQDs as neurotrophic agents. Pristine ZnO nanoparticles as well as composites were duly characterized by using several techniques to confirm the formation of the nanocomposites. Biological evaluation using the neurite outgrowth assay following the cell viability assay revealed that incorporation of GQDs and N-GQDs enhanced the neurite length in comparison to that of pristine ZnO with the nanocomposites of N-GQDs showing comparatively better results, corroborated by the real-time PCR studies as well.

Iron mediated reductive cyclization/oxidation for the generation of chemically diverse scaffolds: An approach in drug discovery

Chemically diverse scaffolds represent a main source of biologically important starting points in drug discovery. Herein, we report the development of such diverse scaffolds from nitroarene/ nitro(hetero)arenes using a key synthetic strategy. In a pilot-scale study, the synthesis of 10 diverse scaffolds was achieved. The 1,7-phenanthroline, thiazolo[5,4-f]quinoline, 2,3-dihydro-1H-pyrrolo[2,3-g]quinoline, pyrrolo[3,2-f]quinoline, 1H-[1,4]oxazino[3,2-g]quinolin-2(3H)-one, [1,2,5]oxadiazolo[3,4-h]quinoline, 7H-pyrido[2,3-c]carbazole, 3H-pyrazolo[4,3-f]quinoline, pyrido[3,2-f]quinoxaline were obtained from nitro hetero arenes in ethanol using iron-acetic acid treatment followed by reaction under oxygen atmosphere. This diverse library is compliant with the rule of five for drug-likeness. The mapping of chemical space represented by these scaffolds revealed a significant contribution to the underrepresented chemical diversity. Crucial to the development of this approach was the mapping of biological space covered by these scaffolds which revealed neurotropic and prophylactic anti-inflammatory activities. In vitro, neuro-biological assays revealed that compounds 14a and 15a showed excellent neurotropic potential and neurite growth compared to controls. Further, anti-inflammatory assays (in vitro and in vivo models) exhibited that Compound 16 showed significant anti-inflammatory activity by attenuating the LPS-induced TNF-α and CD68 levels by modulating the NFkB pathway. In addition, treatment with compound 16 significantly ameliorated the LPS-induced sepsis conditions, and pathological abnormalities (in lung and liver tissues) and improved the survival of the rats compared to LPS control. Owing to their chemical diversity along with bioactivities, it is envisaged that new quality pre-clinical candidates will be generated in the above therapeutic areas using identified leads.

Biological Evaluation of Graphene Quantum Dots and Nitrogen-Doped Graphene Quantum Dots as Neurotrophic Agents

Over time, developments in nano-biomedical research have led to the creation of a number of systems to cure serious illnesses. Tandem use of nano-theragnostics such as diagnostic and therapeutic approaches tailored to the individual disease treatment is crucial for further development in the field of biomedical advancements. Graphene has garnered attention in the recent times as a potential nanomaterial for tissue engineering and regenerative medicines owing to its biocompatibility among the several other unique properties it possesses. The zero-dimensional graphene quantum dots (GQDs) and their nitrogen-doped variant, nitrogen-doped GQDs (N-GQDs), have good biocompatibility, and optical and physicochemical properties. GQDs have been extensively researched owing to several factors such as their size, surface charge, and interactions with other molecules found in biological media. This work briefly elucidates the potential of electroactive GQDs as well as N-GQDs as neurotrophic agents. In vitro investigations employing the N2A cell line were used to evaluate the effectiveness of GQDs and N-GQDs as neurotrophic agents, wherein basic investigations such as SRB assay and neurite outgrowth assay were performed. The results inferred from immunohistochemistry followed by confocal imaging studies as well as quantitative real-time PCR (qPCR) studies corroborated those obtained from neurite outgrowth assay. We have also conducted a preliminary investigation of the pattern of gene expression for neurotrophic and gliotrophic growth factors using ex vivo neuronal and mixed glial cultures taken from the brains of postnatal day 2 mice pups. Overall, the studies indicated that GQDs and N-GQDs hold prospect as a framework for further development of neuroactive compounds for relevant central nervous system (CNS) purposes.

Nanonized carbamazepine for nose-to-brain delivery: pharmaceutical formulation development

Epilepsy is one of the most common neurological disorders in the world. The therapeutic treatment is challenging since conventional drugs have limited efficacy and several side effects that impair patient management. Efforts are being made to find innovative strategies to control epileptic seizures. Intranasal administration provides a convenient route to deliver the drug to the brain. Carbamazepine (CBZ) is an anticonvulsant characterized by poor water solubility, nanonization can improve its bioavailability. Therefore, the design of CBZ nanocrystals (NCs) was assessed to obtain a formulation suitable for nose-to-brain delivery. CBZ NCs were prepared by sonoprecipitation following the Quality by Design approach identifying the impact of process and formulation variables on the critical quality attributes of the final product. The formulation was characterized by a technological point of view (thermotropic behavior, crystallinity, morphology, mucoadhesive strength). Response surface methodology was a reliable tool (error % 2.6) to optimize CBZ NCs with size ≤300 nm. Incubation of CBZ NCs in artificial cerebrospinal fluid at 37 °C did not promote aggregation and degradation phenomena. Preliminary biological studies revealed the biocompatibility of CBZ NCs towards Olfactory Ensheating Cells. The suspension was successfully converted into a powder. The highly concentrated formulation can be obtained, providing the possibility to administer the maximum dose of the drug in the lowest volume.

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.

Neuroprotective and Proneurogenic Effects of Glucosamine in an Internal Carotid Artery Occlusion Model of Ischemia

Neuroprotective, antineuroinflammatory, and proneurogenic effects of glucosamine, a naturally occurring amino sugar, have been reported in various animal models of brain injury including cerebral ischemia and hypoxic brain damage. Given that clinical translation of therapeutic candidates identified in animal models of ischemic stroke has remained unsatisfactory in general, possibly due to inadequacy of existing models, we sought to study the effects of glucosamine in a recently developed, clinical condition mimicking mouse model of internal cerebral artery occlusion. In this model of mild to moderate striatal damage, glucosamine ameliorated behavioral dysfunction, rescued ischemia-induced striatal damage, and suppressed ischemia-induced upregulation of proinflammatory genes in striatal tissue. Further, in ex vivo neurosphere assay involving neural stem cells/neural progenitor cells from subventricular zone, glucosamine increased the number of large neurospheres, along with enhancing mRNA levels of the proliferation markers Nestin, NeuroD1, and Sox2. Lastly, coronal brain sections containing the striatal region with subventricular zone showed increased number of BrdU positive cells and DCX positive cells, a marker for newly differentiating and immature neurons, in glucosamine-treated ischemic mice. Cumulatively, the results confirming neuroprotective, antineuroinflammatory, and proneurogenic effects of glucosamine enhance drug repurposing potential of glucosamine in cerebral ischemia.

Modulation of Brain-Derived Neurotrophic Factor (BDNF) Signaling Pathway by Culinary Sage (Salvia officinalis L.)

Culinary sage (Salvia officinalis L.) is a common spice plant in the mint family (Lamiaceae) well known for its distinctive culinary and traditional medicinal uses. Sage tea has been used traditionally as a brain-enhancing tonic and extracts from sage have been reported to have both cognitive and memory enhancing effects. Brain-derived neurotrophic factor (BDNF) is an endogenous signaling molecule involved in cognition and memory function. In this study, activity-guided fractionation employing preparative reverse-phase high performance liquid chromatography (RP-HPLC) of culinary sage extracts led to the discovery of benzyl 6-O-β-D-apiofuranosyl-β-D-glucoside (B6AG) as a natural product that upregulates transcription of neurotrophic factors in C6 glioma cells. Purified B6AG showed a moderate dose response, with upregulation of BDNF and with EC₅₀ at 6.46 μM. To better understand the natural variation in culinary sage, B6AG was quantitated in the leaves of several commercial varieties by liquid chromatography-mass spectrometry (LC-MS). The level of B6AG in dried culinary sage was found to range from 334 ± 14 to 698 ± 65 μg/g. This study provided a foundation for future investigations, including quantitative inquiries on the distribution of B6AG within the different plant organs, explorations in optimizing post-harvest practices, and aid in the development of sage varieties with elevated levels of B6AG.

AP, Murty US, Chakravarty S, Kumar A. Histone Lysine Demethylase JMJD2D/KDM4D and Family Members Mediate Effects of Chronic Social Defeat Stress on Mouse Hippocampal Neurogenesis and Mood Disorders

Depression, anxiety and related mood disorders are major psychiatric illnesses worldwide, and chronic stress appears to be one of the primary underlying causes. Therapeutics to treat these debilitating disorders without a relapse are limited due to the incomplete molecular understanding of their etiopathology. In addition to the well-studied genetic component, research in the past two decades has implicated diverse epigenetic mechanisms in mediating the negative effects of chronic stressful events on neural circuits. This includes the cognitive circuitry, where the dynamic hippocampal dentate gyrus (DG) neurogenesis gets affected in depression and related affective disorders. Most of these epigenetic studies have focused on the impact of acetylation/deacetylation and methylation of several histone lysine residues on neural gene expression. However, there is a dearth of investigation into the role of demethylation of these lysine residues in chronic stress-induced changes in neurogenesis that results in altered behaviour. Here, using the chronic social defeat stress (CSDS) paradigm to induce depression and anxiety in C57BL/6 mice and ex vivo DG neural stem/progenitor cell (NSCs/NPCs) culture we show the role of the members of the JMJD2/KDM4 family of histone lysine demethylases (KDMs) in mediating stress-induced changes in DG neurogenesis and mood disorders. The study suggests a critical role of JMJD2D in DG neurogenesis. Altered enrichment of JMJD2D on the promoters of Id2 (inhibitor of differentiation 2) and Sox2 (SRY-Box Transcription Factor 2) was observed during proliferation and differentiation of NSCs/NPCs obtained from the DG. This would affect the demethylation of repressive epigenetic mark H3K9, thus activating or repressing these and possibly other genes involved in regulating proliferation and differentiation of DG NSCs/NPCs. Treatment of the NSCs/NPCs culture with Dimethyloxallyl Glycine (DMOG), an inhibitor of JMJDs, led to attenuation in their proliferation capacity. Additionally, systemic administration of DMOG in mice for 10 days induced depression-like and anxiety-like phenotype without any stress exposure.

Ferroptosis Mediates Cuprizone-Induced Loss of Oligodendrocytes and Demyelination

Multiple sclerosis (MS) is a chronic demyelinating disease of the CNS. Cuprizone (CZ), a copper chelator, is widely used to study demyelination and remyelination in the CNS, in the context of MS. However, the mechanisms underlying oligodendrocyte (OL) cell loss and demyelination are not known. As copper-containing enzymes play important roles in iron homeostasis and controlling oxidative stress, we examined whether chelating copper leads to disruption of molecules involved in iron homeostasis that can trigger iron-mediated OL loss. We show that giving mice (male) CZ in the diet induces rapid loss of OL in the corpus callosum by 2 d, accompanied by expression of several markers for ferroptosis, a relatively newly described form of iron-mediated cell death. In ferroptosis, iron-mediated free radicals trigger lipid peroxidation under conditions of glutathione insufficiency, and a reduced capacity to repair lipid damage. This was further confirmed using a small-molecule inhibitor of ferroptosis that prevents CZ-induced loss of OL and demyelination, providing clear evidence of a copper-iron connection in CZ-induced neurotoxicity. This work has wider implications for disorders, such as multiple sclerosis and CNS injury.SIGNIFICANCE STATEMENT Cuprizone (CZ) is a copper chelator that induces demyelination. Although it is a widely used model to study demyelination and remyelination in the context of multiple sclerosis, the mechanisms mediating demyelination is not fully understood. This study shows, for the first time, that CZ induces demyelination via ferroptosis-mediated rapid loss of oligodendrocytes. This work shows that chelating copper with CZ leads to the expression of molecules that rapidly mobilize iron from ferritin (an iron storage protein), that triggers iron-mediated lipid peroxidation and oligodendrocyte loss (via ferroptosis). Such rapid mobilization of iron from cellular stores may also play a role in cell death in other neurologic conditions.

Neuroprotective brain-derived neurotrophic factor signaling in the TAU-P301L tauopathy zebrafish model

Brain-derived neurotrophic factor (BDNF) dysregulations contribute to the neurotoxicity in neurodegenerative pathologies and could be efficiently targeted by therapies. In Alzheimer's disease (AD), although the relationship between BDNF and amyloid load has been extensively studied, how Tau pathology affects BDNF signaling remains unclear. Using the TAU-P301L transgenic zebrafish line, we investigated how early Tau-induced neurotoxicity modifies BDNF signaling. Alterations in BDNF expression levels were observed as early as 48 h post fertilization in TAU-P301L zebrafish embryos while TrkB receptor expression was not affected. Decreasing BDNF expression, using a knockdown strategy in wild-type embryos to mimic Tau-associated decrease, did not modify TrkB expression but promoted neurotoxicity as demonstrated by axonal outgrowth shortening and neuronal cell death. Moreover, the TrkB antagonist ANA-12 reduced the length of axonal projections. Rescue experiments with exogenous BDNF partially corrected neuronal alterations in TAU-P301L by counteracting primary axonal growth impairment but without effect on apoptosis. Importantly, the axonal rescue was proved functionally effective in a behavioral test, at a similar level as obtained with the GSK3β inhibitor LiCl, known to decrease TAU phosphorylation. Finally, treatment with a TrkB agonist, 7,8-dihydroxyflavone, led to comparable results and allowed full rescue of locomotor response. We provided here strong evidence that Tau neurotoxicity provoked alterations in BDNF system and that BDNF pathway might represent an efficient therapeutic target.

Potential Therapeutic Application of Zinc Oxide Nanoflowers in the Cerebral Ischemia Rat Model through Neuritogenic and Neuroprotective Properties

Neuritogenesis, a complex process of the sprouting of neurites, plays a vital role in the structural and functional restoration of cerebral ischemia-injured neuronal tissue. Practically, there is no effective long-term treatment strategy for cerebral ischemia in clinical practice to date due to several limitations of conventional therapies, facilitating the urgency to develop new alternative therapeutic approaches. Herein, for the first time we report that pro-angiogenic nanomaterials, zinc oxide nanoflowers (ZONF), exhibit neuritogenic activity by elevating mRNA expression of different neurotrophins, following PI3K/Akt-MAPK/ERK signaling pathways. Further, ZONF administration to global cerebral ischemia-induced Fischer rats shows improved neurobehavior and enhanced synaptic plasticity of neurons via upregulation of Neurabin-2 and NT-3, revealing their neuroprotective activity. Altogether, this study offers the basis for exploitation of angio-neural cross talk of other pro-angiogenic nano/biomaterials for future advancement of alternative treatment strategies for cerebral ischemia, where neuritogenesis and neural repair are highly critical.

Fellutamide B Synthetic Path Intermediates with in Vitro Neuroactive Function Shows Mood-Elevating Effect in Stress-Induced Zebrafish Model

Fellutamide B is reported to have cytotoxic and proteasome inhibitory activity. Interestingly, fellutamide B and its simplified analogues have also been observed for the neurotrophic activity by stimulating the synthesis and secretion of neurotrophins. Owing to the interesting structural and potent neurotrophic role of fellutamide B (a lipopeptide aldehyde), we have assessed the synthetic path intermediates (compounds A-D) of fellutamide B for their neuroactive potential (in vitro and in vivo). We have observed few compounds (comp #A-D) to have potential neurite outgrowth activity in Neuro2a cells with no observable negative effect on the cell viability. In addition, most compounds (comp #A, C, and D) have shown neurogenic activity ex vivo in hippocampal neurosphere culture, with increased acetyl H3 and acetyl H4 induction ability (comp #C). Furthermore, the intermediate product comp #C has shown anxiolytic and antidepressant-like activity in novel tank test and social interaction test, in the chronic unpredictable stress model of zebrafish mood disorder, inducing BDNF gene expression in the telencephalon region of the fish brain. Our results thus demonstrate that the fellutamide B synthetic path intermediates have potential neurotrophic, neurogenic, and mood-elevating effects and thus good prospect to be developed as potential therapeutics to treat psychiatric disorders.

Mice With Partial Deletion of Y-Heterochromatin Exhibits Stress Vulnerability

The role of Y chromosome in sex determination and male fertility is well established. It is also known that infertile men are prone to psychological disturbances. Earlier studies in the laboratory identified genes expressed in testes that are putatively regulated by Y chromosome in man and mouse. With the availability of a Y-deleted mouse model, that is subfertile, we studied the effect of a partial deletion of Y-chromosomal heterochromatin on mouse behavior when compared to its wild type. The partial Y-deleted mice exhibited anxiety like phenotype under stress when different anxiety (open field test and elevated plus maze, EPM test) and depression related tests (tail suspension and force swim) were performed. The mutant mice also showed reduction in hippocampal neurogenesis and altered expression of neurogenesis markers such as Nestin, Sox2, Gfap, NeuroD1 and Dcx using quantitative real time PCR (qPCR) analysis. The genes with altered expression contained short stretches of homology to Y-derived transcripts only in their Untranslated Regions (UTRs). Our study suggests putative regulation of these genes by the Y chromosome in mouse brain altering stress related behavior.

Absence of Wdr13 Gene Predisposes Mice to Mild Social Isolation - Chronic Stress, Leading to Depression-Like Phenotype Associated With Differential Expression of Synaptic Proteins

We earlier reported that the male mice lacking the Wdr13 gene (Wdr13^-/0) showed mild anxiety, better memory retention, and up-regulation of synaptic proteins in the hippocampus. With increasing evidences from parallel studies in our laboratory about the possible role of Wdr13 in stress response, we investigated its role in brain. We observed that Wdr13 transcript gets up-regulated in the hippocampus of the wild-type mice exposed to stress. To further dissect its function, we analyzed the behavioral and molecular phenotypes of Wdr13^-/0 mice when subjected to mild chronic psychological stress, namely; mild (attenuated) social isolation. We employed iTRAQ based quantitative proteomics, real time PCR and western blotting to investigate molecular changes. Three weeks of social isolation predisposed Wdr13^-/0 mice to anhedonia, heightened anxiety-measured by Open field test (OFT), increased behavior despair- measured by Forced swim test (FST) and reduced dendritic branching along with decreased spine density of hippocampal CA1 neurons as compared to wild-type counterparts. This depression-like-phenotype was however ameliorated when treated with anti-depressant imipramine. Molecular analysis revealed that out of 1002 quantified proteins [1% False discovery rate (FDR), at-least two unique peptides], strikingly, a significant proportion of synaptic proteins including, SYN1, CAMK2A, and RAB3A were down-regulated in the socially isolated Wdr13^-/0 mice as compared to its wild-type counterparts. This was in contrast to the elevated levels of these proteins in non-stressed mutants as compared to the controls. We hypothesized that a de-regulated transcription factor upstream of the synaptic genes might be responsible for the observed phenotype. Indeed, in the socially isolated Wdr13^-/0 mice, there was an up-regulation of GATA1 – a transcription factor that negatively regulates synaptic genes and has been associated with Major Depression (MD) in humans. The present study demonstrates significant genotype × enviornment interaction for Wdr13 gene as shown by the reversal in the expression levels of several synaptic proteins in the mutant vis-à-vis wild-type mouse when exposed to social isolation stress.

Small Molecules: Therapeutic Application in Neuropsychiatric and Neurodegenerative Disorders

In recent years, an increasing number of studies have been published, focusing on the potential therapeutic use of small catalytic agents with strong biological properties. So far, most of these works have only regarded specific clinical fields, such as oncology, infectivology and general pathology, in particular with respect to the treatment of significant inflammatory processes. However, interesting data on possible therapeutic applications of small molecules for the treatment of neuropsychiatric and neurodegenerative illnesses are emerging, especially with respect to the possibility to modulate the cellular redox state. Indeed, a crucial role of redox dysregulation in the pathogenesis of these disorders has been widely demonstrated by both pre-clinical and clinical studies, being the reduction of the total amount of free radicals a promising novel therapeutic approach for these diseases. In this review, we focused our interest on studies published during the last ten years reporting therapeutic potential of small molecules for the treatment of neuropsychiatric and neurodegenerative disorders, also based on the biological efficiency of these compounds in detecting intracellular disturbances induced by increased production of reactive oxygen species.

Potential benefits of mesenchymal stem cells and electroacupuncture on the trophic factors associated with neurogenesis in mice with ischemic stroke

The beneficial effects of mesenchymal stem cells (MSCs) and electroacupuncture (EA) on neurogenesis and related trophic factors remain unclear. Bone marrow MSCs (mBMSC) were transplanted into the striatum of mice with middle cerebral artery occlusion (MCAO), and EA stimulation was applied at two acupoints, Baihui and Dazhui. EA treatment significantly improved motor function, and a synergistic effect of combined mBMSC and EA treatment was observed. Combined mBMSC and EA treatment reduced prominent atrophic changes in the striatum and led to proliferation of neural progenitor cells in the subventricular zone (SVZ) and the surrounding areas of the striatum (SVZ + striatum) of MCAO mice. The mBMSC and EA treatment markedly enhanced mature brain-derived neurotrophic factor (mBDNF) expression in the SVZ + striatum and hippocampus of mice with MCAO, and combined treatment enhanced neurotrophin-4 (NT4) expression. The number of mBDNF- and NT4-positive neurons in the SVZ + striatum and hippocampus increased following EA treatment. Combined treatment led to an increase in the expression levels of phosphorylated cAMP response element binding protein in the neuroblasts of the striatum. Our results indicate that combined MSC and EA treatment may lead to a better therapeutic effect via co-regulation of neurotrophic factors in the brain, by regulating neurogenesis more than single therapy.

A 2-oxa-spiro[5.4]decane scaffold displays neurotrophic, neurogenic and anti-neuroinflammatory activities with high potential for development as a versatile CNS therapeutic

Following our recent discovery of a new scaffold exhibiting significant neurotrophic and neurogenic activities, a structurally tweaked analogue, embodying a 2-oxa-spiro [5.4]decane framework, has been conceptualised and found to be more potent and versatile. It exhibits enhanced neurotrophic and neurogenic action in in vitro, ex vivo and in vivo models and also shows robust neuroprotection in mouse acute cerebral stroke model. The observed attributes are traceable to the predominant activation of the TrkB-PI3K-AKT-CREB pathway. In addition, it also exhibits remarkable anti-neuroinflammatory activity by concurrently down-regulating pro-inflammatory cytokines IL-1α and IL-6, thereby providing a unique molecule with a trinity of neuroactivities, i.e. neurotrophic, neurogenic and anti-inflammatory. The new chemical entity disclosed here has the potential to be advanced as a versatile therapeutic molecule to treat stroke, depression, and possibly other neuropsychiatric disorders associated with attenuated neurotrophic/ neurogenic activity, together with heightened neuroinflammation.

Histone Lysine Demethylases of JMJD2 or KDM4 Family are Important Epigenetic Regulators in Reward Circuitry in the Etiopathology of Depression

Major depressive disorder (MDD) is debilitating mental illness and is one of the leading contributors to global burden of disease, but unfortunately newer and better drugs are not forthcoming. The reason is lack of complete understanding of molecular mechanisms underlying the development of this disorder. Recent research shows dysregulation in epigenetic regulatory mechanisms, particularly the transcriptionally repressive di- and tri-methylation of histone 3 lysine 9 (H3K9me2/me3) in nucleus accumbens (NAc), a critical region of the reward pathway involved in the development of anhedonia, the hallmark of depression. However, the role of histone lysine demethylases, which can remove methylation from H3K9, in particular Jumonji domain containing demethylases 2 or Jmjd2 family, has not been studied. Using social defeat stress-induced mouse model of depression, this study uncovered that transcripts of most of the Jmjd2 members were unchanged after 5 days of defeat during the onset of depression, but were downregulated after 10 days of defeat in full-blown depression. Blocking the Jumonji domain containing demethylases by chronic administration of inhibitors dimethyloxalylglycine (DMOG) and ML324 resulted in depression-like phenotype even in absence of stress exposure, which was associated with an increase in transcriptionally repressive epigenetic marks H3K9me2/me3 in NAc, causing altered neuroplastic changes as reported in NAc in depression models. Thus, we report for the first time that Jmjd2 class demethylases are critical epigenetic regulators involved in etiopathology of depression and related disorders and activation of these demethylases can be a good strategy in the treatment of MDD and related psychiatric disorders.

Implication of Genetic Deletion of Wdr13 in Mice: Mild Anxiety, Better Performance in Spatial Memory Task, with Upregulation of Multiple Synaptic Proteins

WDR13 expresses from the X chromosome and has a highly conserved coding sequence. There have been multiple associations of WDR13 with memory. However, its detailed function in context of brain and behavior remains unknown. We characterized the behavioral phenotype of 2 month old male mice lacking the homolog of WDR13 gene (Wdr13^−/0). Taking cue from analysis of its expression in the brain, we chose hippocampus for molecular studies to delineate its function. Wdr13^−/0 mice spent less time in the central area of the open field test (OFT) and with the novel object in novel object recognition test (NOR) as compared to the wild-type. However, these mice didn't show any significant changes in total time spent in arms or in frequency of arm entries in elevated plus maze (EPM). In the absence of Wdr13, there was a significant upregulation of synaptic proteins, viz., SYN1, RAB3A, CAMK2A etc. accompanied with increased spine density of hippocampal CA1 neurons and better spatial memory in mice as measured by increased time spent in the target quadrant of Morris water maze (MWM) during probe test. Parallel study from our lab has established c-JUN, ER α/β, and HDAC 1,3,7 as interacting partners of WDR13. WDR13 represses transcription from AP1 (c-JUN responsive) and Estrogen Receptor Element (ERE) promoters. We hypothesized that absence of Wdr13 would result in de-regulated expression of a number of genes including multiple synaptic genes leading to the observed phenotype. Knocking down Wdr13 in Neuro2a cell lines led to increased transcripts of Camk2a and Nrxn2 consistent with in-vivo results. Summarily, our data provides functional evidence for the role of Wdr13 in brain.

Neurotrophin receptor agonists and antagonists as therapeutic agents: An evolving paradigm

Neurodegenerative disorders are prevalent, complex and devastating conditions, with very limited treatment options currently available. While they manifest in many forms, there are commonalities that link them together. In this review, we will focus on neurotrophins - a family of related factors involved in neuronal development and maintenance. Neurodegenerative diseases often present with a neurotrophin imbalance, in which there may be decreases in trophic signaling through Trk receptors for example, and/or increases in pro-apoptotic activity through p75. Clinical trials with neurotrophins have continuously failed due to their poor pharmacological properties as well as the unavoidable activation of p75. Thus, there is a need for drugs without such setbacks. Small molecule neurotrophin mimetics are favorable options since they can selectively activate Trks or inactivate p75. In this review, we will initially present a brief outline of how these molecules are synthesized and their mechanisms of action; followed by an update in the current state of neurotrophins and small molecules in major neurodegenerative diseases. Although there has been significant progress in the development of potential therapeutics, more studies are needed to establish clear mechanisms of action and target specificity in order to transition from animal models to the assessment of safety and use in humans.

Preparation of honokiol with biodegradable nanoparticles for treatment of osteosarcoma

Hon/MPEG-PCL nanoparticles were parpered by self-assembly method and showed therapeutic potential in the treatment of osteosarcoma.