Logic "AND Gate Circuit" Based Mussel Inspired Polydopamine Nanocomposite as Bioactive Antioxidant for Management of Oxidative Stress and Neurogenesis in Traumatic Brain Injury.

In the intricate landscape of Traumatic Brain Injury (TBI), the management of TBI remains a challenging task due to the extremely complex pathophysiological conditions and excessive release of reactive oxygen species (ROS) at the injury site and the limited regenerative capacities of the central nervous system (CNS). Existing pharmaceutical interventions are limited in their ability to efficiently cross the blood-brain barrier (BBB) and expeditiously target areas of brain inflammation. In response to these challenges herein, we designed novel mussel inspired polydopamine (PDA)-coated mesoporous silica nanoparticles (PDA-AMSNs) with excellent antioxidative ability to deliver a new potential therapeutic GSK-3ß inhibitor lead small molecule abbreviated as Neuro Chemical Modulator (NCM) at the TBI site using a neuroprotective peptide hydrogel (PANAP). PDA-AMSNs loaded with NCM (i.e., PDA-AMSN-D) into the matrix of PANAP were injected into the damaged area in an in vivo cryogenic brain injury model (CBI). This approach is specifically built while keeping the logic AND gate circuit as the primary focus. Where NCM and PDA-AMSNs act as two input signals and neurological functional recovery as a single output. Therapeutically, PDA-AMSN-D significantly decreased infarct volume, enhanced neurogenesis, rejuvenated BBB senescence, and accelerated neurological function recovery in a CBI.

Power of Dopamine: Multifunctional Compound Assisted Conversion of the Most Risk Factor into Therapeutics of Alzheimer's Disease.

In Alzheimer's disease (AD), reactive oxygen species (ROS) plays a crucial role, which is produced from molecular oxygen with extracellular deposited amyloid-ß (Aß) aggregates through the reduction of a Cu2+ ion. In the presence of a small amount of redox-active Cu2+ ion, ROS is produced by the Aß-Cu2+ complex as Aß peptide alone is unable to generate excess ROS. Therefore, Cu2+ ion chelators are considered promising therapeutics against AD. Here, we have designed and synthesized a series of Schiff base derivatives (SB) based on 2-hydroxy aromatic aldehyde derivatives and dopamine. These SB compounds contain one copper chelating core, which captures the Cu2+ ions from the Aß-Cu2+ complex. Thereby, it inhibits copper-induced amyloid aggregation as well as amyloid self-aggregation. It also inhibits copper-catalyzed ROS production through sequestering of Cu2+ ions. The uniqueness of our designed ligands has the dual property of dopamine, which not only acts as a ROS scavenger but also chelates the copper ion. The crystallographic analysis proves the power of the dopamine unit. Therefore, dual exploration of dopamine core can be considered as potential therapeutics for future AD treatment.

Hydrophobic C-Terminal Peptide Analog Aß31-41 Protects the Neurons from Aß-Induced Toxicity.

Spontaneous aggregation of amyloid beta (Aß) leads to the formation of neurotoxic senile plaque considered as the most crucial event in Alzheimer's disease (AD) progression. Inhibition or disruption of this deadly aggregate formation is one of the most efficient strategies for the development of potential therapeutics, and extensive research is in progress by various research groups. In this direction, the development of a peptide analogous to that of the native Aß peptide is an attractive strategy. Based on this rationale, ß-sheet breakers were developed from the Aß central hydrophobic core. These peptide derivatives will bind to the full length of the parent Aß and interfere in self-recognition, thereby preventing the folding of the Aß peptide into cross ß-sheet neurotoxic aggregates. However, this approach is effective in the inhibition of fibrillar aggregation, but this strategy is ineffective in the Aß neurotoxic oligomer formation. Therefore, an alternative and efficient approach is to use the Aß peptide analogous to the C-terminal region, which arbitrates fibrillation and oligomerization. Herein, we developed the Aß C-terminal fragment (ACT-1 to ACT-7) for inhibition of oligomerization as well as fibrillar aggregation. Screening of these seven peptides resulted in an efficient anti-Aß peptide aggregative agent (ACT-7), which was evaluated by the ThT assay peptide. The ThT assay reveals complete inhibition and showed significant neuroprotection of PC-12-derived neurons from Aß-induced toxicity and reduced cell apoptosis. Further, analysis using CD and FTIR spectroscopy reveals that the ACT-7 peptide efficiently inhibits the formation of the ß-sheet secondary structure content. HR-TEM microscopic analysis confirmed the inhibition of formation. Therefore, the inhibition of ß-sheet Aß fibrillary aggregation by the protease-stable ACT-7 peptide may provide a beneficial effect on AD treatment to control the Aß aggregates. Finally, we anticipate that our newly designed ACT peptides may also assist as a template molecular scaffold for designing potential anti-AD therapeutics.

Molecular mechanism of cognitive impairment associated with Parkinson's disease: A stroke perspective.

Parkinson's disease (PD) is a common neurological illness that causes several motor and non-motor symptoms, most characteristically limb tremors and bradykinesia. PD is a slowly worsening disease that arises due to progressive neurodegeneration of specific areas of the brain, especially the substantia nigra of the midbrain. Even though PD has continuously been linked to a higher mortality risk in numerous epidemiologic studies, there have been significant discoveries regarding the connection between PD and stroke. The incidence of strokes such as cerebral infarction and hemorrhage is substantially associated with the development of PD. Moreover, cognitive impairments, primarily dementia, have been associated with stroke and PD. However, the underlying molecular mechanism of this phenomenon is still obscure. This concise review focuses on the relationship between stroke and PD, emphasizing the molecular mechanism of cognition deficit and memory loss evident in PD and stroke. Furthermore, we are also highlighting some potential drug molecules that can target both PD and stroke.

High-Affinity Fluorescent Probes for the Detection of Soluble and Insoluble Aß Deposits in Alzheimer's Disease.

The overproduction and deposition of the amyloid-ß (Aß) aggregates are accountable for the genesis and development of the neurologic disorder Alzheimer's disease (AD). Effective medications and detection agents for AD are still deficient. General challenges for the diagnosis of Aß aggregates in the AD brain are (i) crossing the blood-brain barrier (BBB) and (ii) selectivity to Aß species with (iii) emission maxima in the 500-750 nm region. Thioflavin-T (ThT) is the most used fluorescent probe for imaging Aß fibril aggregates. However, because of the poor BBB crossing (log P = -0.14) and short emission wavelength (482 nm) after binding with Aß fibrils, ThT can be limited to in vitro use only. Herein, we have developed Aß deposit-recognizing fluorescent probes (ARs) with a D-π-A architecture and a longer emission wavelength after binding with Aß species. Among the newly designed probes, AR-14 showed an admirable fluorescence emission (>600 nm) change after binding with soluble Aß oligomers (2.3-fold) and insoluble Aß fibril aggregates (4.5-fold) with high affinities Kd = 24.25 ± 4.10 nM; Ka = (4.123 ± 0.69) × 107 M-1 for fibrils; Kd = 32.58 ± 4.89 nM; and Ka = (3.069 ± 0.46) × 107 M-1 for oligomers with high quantum yield, molecular weight of <500 Da, reasonable log P = 1.77, stability in serum, and nontoxicity, and it can cross the BBB efficiently. The binding affinity of AR-14 toward Aß species is proved by fluorescence binding studies and fluorescent staining of 18-month-old triple-transgenic (3xTg) mouse brain sections. In summary, the fluorescent probe AR-14 is efficient and has an admirable quality for the detection of soluble and insoluble Aß deposits in vitro and in vivo.

Vanillin Benzothiazole Derivative Reduces Cellular Reactive Oxygen Species and Detects Amyloid Fibrillar Aggregates in Alzheimer's Disease Brain.

The misfolding of amyloid beta (Aß) peptides into Aß fibrillary aggregates is a major hallmark of Alzheimer's disease (AD), which responsible for the excess production of hydrogen peroxide (H2O2), a prominent reactive oxygen species (ROS) from the molecular oxygen (O2) by the reduction of the Aß-Cu(I) complex. The excessive production of H2O2 causes oxidative stress and inflammation in the AD brain. Here, we have designed and developed a dual functionalized molecule VBD by using π-conjugation (C═C) in the backbone structure. In the presence of H2O2, the VBD can turn into fluorescent probe VBD-1 by cleaving of the selective boronate ester group. The fluorescent probe VBD-1 can undergo intramolecular charge transfer transition (ICT) by a π-conjugative system, and as a result, its emission increases from the yellow (532 nm) to red (590 nm) region. The fluorescence intensity of VBD-1 increases by 3.5-fold upon binding with Aß fibrillary aggregates with a high affinity (Kd = 143 ± 12 nM). Finally, the VBD reduces the cellular toxic H2O2 as proven by the CCA assay and DCFDA assay and the binding affinity of VBD-1 was confirmed by using in vitro histological staining in 8- and 18-month-old triple transgenic AD (3xTg-AD) mice brain slices.

Short Peptoid Evolved from the Key Hydrophobic Stretch of Amyloid-ß42 Peptide Serves as a Potent Therapeutic Lead of Alzheimer's Disease.

Amyloid-ß 42(Aß42), an enzymatically cleaved (1-42 amino acid long) toxic peptide remnant, has long been reported to play the key role in Alzheimer's disease (AD). Aß42 also plays the key role in the onset of other AD-related factors including hyperphosphorylation of tau protein that forms intracellular neurofibrillary tangles, imbalances in the function of the neurotransmitter acetylcholine, and even generation of reactive oxygen species (ROS), disrupting the cytoskeleton and homeostasis of the cell. To address these issues, researchers have tried to construct several strategies to target multiple aspects of the disease but failed to produce any clinically successful therapeutic molecules. In this article, we report a new peptoid called RA-1 that was designed and constructed from the hydrophobic stretch of the Aß42 peptide, 16KLVFFA21. This hydrophobic stretch is primarily responsible for the Aß42 peptide aggregation. Experimental study showed that the RA-1 peptoid is stable under proteolytic conditions, can stabilize the microtubule, and can inhibit the formation of toxic Aß42 aggregates by attenuating hydrophobic interactions between Aß42 monomers. Furthermore, results from various intracellular assays showed that RA-1 inhibits Aß42 fibril formation caused by the imbalance in AchE activity, reduces the production of cytotoxic reactive oxygen species (ROS), and promotes neurite outgrowth even in the toxic environment. Remarkably, we have also demonstrated that our peptoid has significant ability to improve the cognitive ability and memory impairment in in vivo rats exposed to AlCl3 and d-galactose (d-gal) dementia model. These findings are also validated with histological studies. Overall, our newly developed peptoid emerges as a multimodal potent therapeutic lead molecule against AD.

Evolution of Potential Antimitotic Stapled Peptides from Multiple Helical Peptide Stretches of the Tubulin Heterodimer Interface: Helix-Mimicking Stapled Peptide Tubulin Inhibitors.

Protein-protein interactions play a crucial role in microtubule dynamics. Microtubules are considered as a key target for the design and development of anticancer therapeutics, where inhibition of tubulin-tubulin interactions plays a crucial role. Here, we focused on a few key helical stretches at the interface of α,ß-tubulin heterodimers and developed a structural mimic of these helical peptides, which can serve as potent inhibitors of microtubule polymerization. To induce helicity, we have made stapled analogues of these sequences. Thereafter, we modified the lead sequences of the antimitotic stapled peptides with halo derivatives. It is observed that halo-substituted stapled peptides follow an interesting trend for the electronegativity of halogen atoms in interaction patterns with tubulin and a correlation in the toxicity profile. Remarkably, we found that para-fluorophenylalanine-modified stapled peptide is the most potent inhibitors, which perturbs microtubule dynamics, induces apoptotic death, and inhibits the growth of melanoma.

Design and Development of Benzothiazole-Based Fluorescent Probes for Selective Detection of Aß Aggregates in Alzheimer's Disease.

The formation and accumulation of amyloid beta (Aß) peptide are considered the crucial events that are responsible for the progression of Alzheimer's disease (AD). Herein, we have designed and synthesized a series of fluorescent probes by using electron acceptor-donor end groups interacting with a π-conjugating system for the detection of Aß aggregates. The chemical structure of these probes denoted as RMs, having a conjugated π-system (C═C), showed a maximum emission in PBS (>600 nm), which is the best range for a fluorescent imaging probe. Among all these probes, RM-28 showed an excellent fluorescence property with an emission maximum of >598 nm upon binding to Aß aggregates. RM-28 also showed high sensitivity (7.5-fold) and high affinities toward Aß aggregates (Kd = 175.69 ± 4.8 nM; Ka = 0.5 × 107 M-1). It can cross the blood-brain barrier of mice efficiently. The affinity of RM-28 toward Aß aggregates was observed in 3xTg-AD brain sections of the hippocampus and cortex region using a fluorescent imaging technique, as well as an in vitro fluorescence-based binding assay with Aß aggregates. Moreover, RM-28 is highly specific to Aß aggregates and does not bind with intracellular proteins like bovine serum albumin (BSA) and α-synuclein (α-Syn) aggregates. The results indicate that the probe RM-28 emerges as an efficient and veritable highly specific fluorescent probe for the detection of Aß aggregates in both in vitro and in vivo model systems.

Human Serum Albumin-Inspired Glycopeptide-Based Multifunctional Inhibitor of Amyloid-ß Toxicity.

In Alzheimer's disease (AD), insoluble Aß42 peptide fragments self-aggregate and form oligomers and fibrils in the brain, causing neurotoxicity. Further, the presence of redox-active metal ions such as Cu2+ enhances the aggregation process through chelation with these Aß42 aggregates as well as generation of Aß42-mediated reactive oxygen species (ROS). Herein, we have adopted a bioinspired strategy to design and develop a multifunctional glycopeptide hybrid molecule (Glupep), which can serve as a potential AD therapeutic. This molecule consists of a natural metal-chelating tetrapeptide motif of human serum albumin (HSA), a ß-sheet breaker peptide, and a sugar moiety for better bioavailability. We performed different biophysical and docking experiments, which revealed that Glupep not only associates with Aß42 but also prevents its self-aggregation to form toxic oligomers and fibrils. Moreover, Glupep was also shown to sequester out Cu2+ from the Aß-Cu2+ complex, reducing the ROS formation and toxicity. Besides, this study also revealed that Glupep could protect PC12-derived neurons from Aß-Cu2+-mediated toxicity by reducing intracellular ROS generation and stabilizing the mitochondrial membrane potential. All these exciting features show Glupep to be a potent inhibitor of Aß42-mediated multifaceted toxicity and a prospective therapeutic lead for AD.

Rhodamine-Based Metal Chelator: A Potent Inhibitor of Metal-Catalyzed Amyloid Toxicity.

Alzheimer's disease (AD) exhibits a multitude of syndromes which add up to its complex nature. In AD, amyloid plaques are deposited along with abnormal accumulation of transition-metal ions. These transition-metal ions are redox-active and help to induce the formation of various polymorphic forms of amyloid-ß. Amyloid oligomeric and fibrillar aggregates are the main cause for neuronal toxicity. Another reason for neuronal toxicity arises from generation of reactive oxygen species (ROS) catalyzed by redox-active metal ions through Fenton's reaction. In this direction, an Aß inhibitor possessing the metal chelation property will be the most promising approach against multifaceted AD. Herein, a rhodamine-B-based compound (Rh-BT) has been designed and synthesized. Rhodamine was attached with benzothiazole as a recognition unit for amyloid-ß aggregates. The molecule can effectively capture redox metal ions from the Aß-Cu2+ complex as well as inhibit Aß self-assembly such as toxic oligomeric and fibrillar aggregates. Various biophysical assays show that Rh-BT interacts with the Aß peptide, is capable of decreasing metal-induced ROS generation, and inhibits Aß-Cu2+-induced cytotoxicity. All these results support the multifunctional nature of Rh-BT, which has an Aß-specific recognition unit. In addition to the above properties, Rh-BT also exhibits good serum stability in vivo and blood-brain barrier permeability. Therefore, Rh-BT can be considered as a potent multifunctional therapeutic for the treatment of AD.

Extracellular Matrix (ECM)-Mimicking Neuroprotective Injectable Sulfo-Functionalized Peptide Hydrogel for Repairing Brain Injury.

Brain injury can lead to the loss of neuronal functions and connections, along with the damage of the extracellular matrix (ECM). Thus, it ultimately results in devastating long-term damage, and recovery from this damage is a challenging task. To address this issue, we have designed a sulfo-group-functionalized injectable biocompatible peptide hydrogel, which not only mimics the ECM and supports the damaged neurons but also releases a neurotrophic factor around the injured sites of the brain in the presence of the matrix metalloproteinase 9 (MMP9) enzyme. It has also been observed that the driving force of hydrogel formation is a ß-sheet secondary structure and π-π stacking interactions between Phe-Phe moieties. The hydrogel is able not only to promote neurite outgrowth of PC12-derived neurons and primary neurons cultured in its presence but also to nullify the toxic effects of anti-nerve growth factor (Anti-NGF)-induced neurons. It also promotes the expression of vital neuronal markers in rat cortical primary neurons, displays substantial potential in neuroregeneration, and also promotes fast recovery of the sham injured mice brain. Increased expression of reactive astrocytes in the hippocampal dentate gyrus region of the sham injured brain clearly suggests its tremendous ability in the neural repair of the damaged brain. Thus, we can convincingly state that our hydrogel is capable of repairing brain injury by mimicking an ECM-like environment and providing neuroprotection to the damaged neurons.

Generation of Neurospheres from Mixed Primary Hippocampal and Cortical Neurons Isolated from E14-E16 Sprague Dawley Rat Embryo.

Primary neuron culture is an essential technique in the field of neuroscience. To gain deeper mechanistic insights into the brain, it is essential to have a robust in vitro model that can be exploited for various neurobiology studies. Though primary neuron cultures (i.e., long-term hippocampal cultures) have provided scientists with models, it does not yet represent the complexity of brain network completely. In the wake of these limitations, a new model has emerged using neurospheres, which bears a closer resemblance to the brain tissue. The present protocol describes the plating of high and low densities of mixed cortical and hippocampal neurons isolated from the embryo of embryonic day 14-16 Sprague Dawley rats. This allows for the generation of neurospheres and long-term primary neuron culture as two independent platforms to conduct further studies. This process is extremely simple and cost-effective, as it minimizes several steps and reagents previously deemed essential for neuron culture. This is a robust protocol with minimal requirements that can be performed with achievable results and further used for a diversity of studies related to neuroscience.

In Silico Approach for Designing Potent Neuroprotective Hexapeptide.

Alzheimer's disease (AD) is a constantly recurring neurodegenerative disease that deteriorates over a period of time. In this pathology, connections between neurons become extremely damaged due to the deposition of senile plaques in the membrane region, which results in abnormal signal transduction processes. Also, the intracellular microtubule networks are disrupted in the hyperphosphorylated tau cascade of AD. Therefore, design and development of potent neuroprotective molecules that can instantaneously target multiple facets of AD pathogenesis are greatly needed to tackle this unmet medical need. Here, we have implemented a pharmacophore based in silico analysis of various neuroprotective peptides known for neurotherapeutic application in AD. Fascinatingly, we have identified an active core of these peptides and designed a library of hexapeptides. We observed that peptide "LETVNQ" (LE6) has shown significant protection ability against degeneration of neurons. Experimental evidence suggests that this peptide immensely reduced the aggregation rate of amyloid-ß (Aß) and helped in microtubule polymerization. Intriguingly, this newly designed peptide does not have any cytotoxicity toward differentiated PC12 neurons; rather it helps in neurite outgrowth. Further, LE6 helps to maintain the complex microtubule network in cells by promoting the polymerization rate of intracellular microtubules and mediates excellent protection of neurons even after removal of nerve growth factor (NGF). Finally, we observed that this LE6 peptide has substantial stability under physiological conditions and helps to retain healthy morphology of primary rat cortical neurons. This excellent piece of work identifies a potent hexapeptide, which has exceptional ability to protect neurons as well as microtubule from degeneration and may become potent therapeutics against AD pathogenesis in the future.

Dual-Arm Nanocapsule Targets Neuropilin-1 Receptor and Microtubule: A Potential Nanomedicine Platform.

A multiarm nanomedicine template has been designed following bottom-up approach, which target neuropilin-1 (Nrp-1) receptor of cancer cells. Through this venture, we discovered that cucurbit [6] uril (CB [6]) binds with tubulin close to binding pocket of vinblastine site and perturbs tubulin polymerization. To increase the specificity of gold nanoparticle (GNP) toward Nrp-1-rich cancer cells, we further modified this GNP with Nrp-1 receptor-specific short peptide (CGNKRTR). Remarkably, we found an interesting self-assembly process upon addition of curcumin into the CB [6] and peptide-functionalized GNP, leading to the formation of a spherical nanocapsule (CGNP·Cur). It can deliver and release significantly higher amounts of anticancer drug curcumin in Nrp-1-rich cancer cells. It causes microtubule depolymerization and significant tumor regression in Nrp-1 overexpressed mice melanoma model. These interesting findings show that nanocapsule has high potential to develop a powerful anticancer nanomedicine and help in its preclinical validation.

Potential Neuroprotective Peptide Emerged from Dual Neurotherapeutic Targets: A Fusion Approach for the Development of Anti-Alzheimer's Lead.

Amyloid-beta (Aß) peptide misfolds into fibrillary aggregates (ß-sheet) and is deposited as amyloid plaques in the cellular environment, which severely damages intraneuronal connections leading to Alzheimer's disease (AD) pathogenesis. Furthermore, neurons are rich in tubulin/microtubules, and the intracellular network of microtubules also gets disrupted by the accumulation of Aß fiber in the brain. Hence, development of new potent molecules, which can simultaneously inhibit Aß fibrillations and stabilize microtubules, is particularly needed for the efficient therapeutic application in AD. To address these issues, here we introduced an innovative fusion strategy to design and develop next generation anti-AD therapeutic leads. This unexplored fusion strategy entails design and development of a potent nonapeptide by taking into account both the hydrophobic core (17-21) of Aß peptide and the taxol binding region of ß-tubulin. In vitro results suggest that this newly designed peptide interacts at the taxol binding region of ß-tubulin with a moderate binding affinity and promotes microtubule polymerization. It has the ability to bind at the hydrophobic core (17-21) of Aß, responsible for its aggregation, and prevent amyloid fibril as well as plaque formation. In addition, it interacts at the CAS site (catalytic anionic site) of acetylcholinesterase (AChE) and significantly inhibits AChE induced Aß fibrillation, stimulates neurite branching, and provides stability to intracellular microtubules and extensive protection of neurons against nerve growth factor (NGF) deprived neuron toxicity. Moreover, this newly designed peptide shows good stability in serum obtained from humans and efficiently permeates the blood-brain barrier (BBB) without showing any toxicity toward differentiated PC12 neurons as well as primary rat cortical neurons. This excellent feature of protecting the neurons by stabilizing the microtubules without showing any toxicity toward neurons will make this peptide a potent therapeutic agent of AD in the near future.

Discovery of Neuroregenerative Peptoid from Amphibian Neuropeptide That Inhibits Amyloid-ß Toxicity and Crosses Blood-Brain Barrier.

Development of potential therapeutics for Alzheimer's disease (AD) requires a multifaceted strategy considering the high levels of complexity of the human brain and its mode of function. Here, we adopted an advanced strategy targeting two key pathological hallmarks of AD: senile plaques and neurofibrillary tangles. We derived a lead short tetrapeptide, Ser-Leu-Lys-Pro (SLKP), from a dodeca-neuropeptide of amphibian (frog) brain. Results suggested that the SLKP peptide had a superior effect compared to the dodecapeptide in neuroprotection. This result encouraged us to adopt peptidomimetic approach to synthesize an SLKP peptoid. Remarkably, we found that the SLKP peptoid is more potent than its peptide analogue, which significantly inhibits Aß fibrillization, moderately binds with tubulin, and promotes tubulin polymerization as well as stabilization of microtubule networks. Further, we found that SLKP peptoid is stable in serum, shows significant neuroprotection against Aß mediated toxicity, promotes significant neurite outgrowth, maintains healthy morphology of rat primary cortical neurons and crosses the blood-brain barrier (BBB). To the best of our knowledge, our SLKP peptoid is the first and shortest peptoid to show significant neuroprotection and neuroregeneration against Aß toxicity, as well as to cross the BBB offering a potential lead for AD therapeutics.

Neuro-Regenerative Choline-Functionalized Injectable Graphene Oxide Hydrogel Repairs Focal Brain Injury.

Brain damage is associated with spatial imbalance of cholinergic system, which makes severe impact in recovery of damaged neurons of brain. Therefore, maintenance of cholinergic system is extremely important. Here, we fabricated an injectable hydrogel with acetylcholine-functionalized graphene oxide and poly(acrylic acid). Results revealed that this hydrogel is non-cytotoxic, promotes neurite outgrowth, stabilizes microtubule networks, and enhances the expression of some key neural markers in rat cortical primary neurons. Further, this hydrogel exhibits significant potential in neuro-regeneration and also promotes fast recovery of the sham injured mice brain. Moreover, we found significant enhancement of reactive astrocytes in the hippocampal dentate gyrus region of the sham injured brain, indicating its excellent potential in neural repair of the damaged brain. Finally, above results clearly indicate that this neuro-regenerative hydrogel is highly capable of maintaining the cholinergic balance through local release of acetylcholine in the injured brain, which is crucial for brain repair.

Power of Tyrosine Assembly in Microtubule Stabilization and Neuroprotection Fueled by Phenol Appendages.

Microtubules play a crucial role in maintenance of structure, function, axonal extensions, cargo transport, and polarity of neurons. During neurodegenerative diseases, microtubule structure and function get severely damaged due to destabilization of its major structural proteins. Therefore, design and development of molecules that stabilize these microtubule networks have always been an important strategy for development of potential neurotherapeutic candidates. Toward this venture, we designed and developed a tyrosine rich trisubstituted triazine molecule (TY3) that stabilizes microtubules through close interaction with the taxol binding site. Detailed structural investigations revealed that the phenolic protons are the key interacting partners of tubulin. Interestingly, we found that this molecule is noncytotoxic in PC12 derived neurons, stabilizes microtubules against nocodazole induced depolymerization, and increases expression of acetylated tubulin (Ac-K40), an important marker of tubulin stability. Further, results show that TY3 significantly induces neurite sprouting as compared to the untreated control as well as the two other analogues (TS3 and TF3). It also possesses anti-Aß fibrillation properties as confirmed by ThT assay, which leads to its neuroprotective effect against amyloidogenic induced toxicity caused through nerve growth factor (NGF) deprivation in PC12 derived neurons. Remarkably, our results reveal that it reduces the expression of TrkA (pY490) associated with NGF deprived amyloidogenesis, which further proves that it is a potent amyloid ß inhibitor. Moreover, it promoted the health of the rat primary cortical neurons through higher expression of key neuronal markers such as MAP2 and Tuj1. Finally, we observed that it has good serum stability and has the ability to cross the blood-brain barrier (BBB). Overall, our work indicates the importance of phenolic -OH in promoting neuroprotection and its importance could be implemented in the development of future neurotherapeutics.

Neurosphere Development from Hippocampal and Cortical Embryonic Mixed Primary Neuron Culture: A Potential Platform for Screening Neurochemical Modulator.

Reconstitution of a complex biological structure or system following a simple and facile strategy using minimum physiochemical cues is challenging for an in-depth understanding of the system. In particular, the brain is a highly sophisticated and complex network of trillions of neurons and glial cells that controls function of our body. Understanding this complex machinery requires an innovative and simple bottom-up approach. In this venture, we report an easy and efficient strategy to culture cortical and hippocampal primary neurons from the E14-E16 embryo of Sprague-Dawley rat. This generates spontaneous neurospheres within 6-7 days of primary neuron culture of E14-E16 embryo. It further proliferates and forms radial glia-like structures, which are known to be the primary neural progenitor cells that differentiate into neurons, astrocytes, and oligodendrocytes. Interestingly, neurospheres lead to the formation of large projection neurons and radial glia, which mimic the early stage of cortical development in an in vivo system. Overall, this new, facile, strategic mixed primary neuron culture method offers a potential platform for understanding the effect of neurochemical modulators, which has tremendous future implications in the screening of neurotherapeutics.