TREM2 drives microglia response to amyloid-ß via SYK-dependent and -independent pathways.

Genetic studies have highlighted microglia as pivotal in orchestrating Alzheimer's disease (AD). Microglia that adhere to Aß plaques acquire a transcriptional signature, "disease-associated microglia" (DAM), which largely emanates from the TREM2-DAP12 receptor complex that transmits intracellular signals through the protein tyrosine kinase SYK. The human TREM2R47H variant associated with high AD risk fails to activate microglia via SYK. We found that SYK-deficient microglia cannot encase Aß plaques, accelerating brain pathology and behavioral deficits. SYK deficiency impaired the PI3K-AKT-GSK-3ß-mTOR pathway, incapacitating anabolic support required for attaining the DAM profile. However, SYK-deficient microglia proliferated and advanced to an Apoe-expressing prodromal stage of DAM; this pathway relied on the adapter DAP10, which also binds TREM2. Thus, microglial responses to Aß involve non-redundant SYK- and DAP10-pathways. Systemic administration of an antibody against CLEC7A, a receptor that directly activates SYK, rescued microglia activation in mice expressing the TREM2R47H allele, unveiling new options for AD immunotherapy.

Multi-signal regulation of the GSK-3ß homolog Rim11 controls meiosis entry in budding yeast.

Starvation in diploid budding yeast cells triggers a cell-fate program culminating in meiosis and spore formation. Transcriptional activation of early meiotic genes (EMGs) hinges on the master regulator Ime1, its DNA-binding partner Ume6, and GSK-3ß kinase Rim11. Phosphorylation of Ume6 by Rim11 is required for EMG activation. We report here that Rim11 functions as the central signal integrator for controlling Ume6 phosphorylation and EMG transcription. In nutrient-rich conditions, PKA suppresses Rim11 levels, while TORC1 retains Rim11 in the cytoplasm. Inhibition of PKA and TORC1 induces Rim11 expression and nuclear localization. Remarkably, nuclear Rim11 is required, but not sufficient, for Rim11-dependent Ume6 phosphorylation. In addition, Ime1 is an anchor protein enabling Ume6 phosphorylation by Rim11. Subsequently, Ume6-Ime1 coactivator complexes form and induce EMG transcription. Our results demonstrate how various signaling inputs (PKA/TORC1/Ime1) converge through Rim11 to regulate EMG expression and meiosis initiation. We posit that the signaling-regulatory network elucidated here generates robustness in cell-fate control.

Wireless Photoactivated Targeted Nanosystem for Oncotherapy Via Synergistic Effects of Hyperthermia/Redox Stress Amplification/GSK-3ß Activity Inhibition.

Highly soluble salts and gas mediated therapies are emerging antitumor strategies. However, the therapeutic efficacy remains restricted by difficulty in delivering them to the tumor site and poorly controlled release in deep tissues. Here, an intelligent wireless photoactivated targeted nanosystem is designed for delivering LiCl and H2 to tumors for therapy. LiCl causes cell death by inhibiting the activity of GSK-3ß. H2 selectively interacts with reactive oxygen species in the tumor, leading to redox stress, which induces apoptosis. The significant heat generated by the nanosystem not only kills tumor cells but also accelerates the dissolution of LiCl and the release of H2. The rapid dissolution of LiCl leads to a surge in intracellular osmotic pressure, which further intensifies the redox stress response and enhances the efficiency of therapy. The nanosystem shows efficient tumor therapeutic capability via synergistic effects of hyperthermia/redox stress amplification/GSK-3ß activity inhibition.

Liraglutide versus pramlintide in protecting against cognitive function impairment through affecting PI3K/AKT/GSK-3ß/TTBK1 pathway and decreasing Tau hyperphosphorylation in high-fat diet- streptozocin rat model.

The American Diabetes Association guidelines (2021) confirmed the importance of raising public awareness of diabetes-induced cognitive impairment, highlighting the links between poor glycemic control and cognitive impairment. The characteristic brain lesions of cognitive dysfunction are neurofibrillary tangles (NFT) and senile plaques formed of amyloid-ß deposition, glycogen synthase kinase 3 beta (GSK3ß), and highly homologous kinase tau tubulin kinase 1 (TTBK1) can phosphorylate Tau proteins at different sites, overexpression of these enzymes produces extensive phosphorylation of Tau proteins making them insoluble and enhance NFT formation, which impairs cognitive functions. The current study aimed to investigate the potential contribution of liraglutide and pramlintide in the prevention of diabetes-induced cognitive dysfunction and their effect on the PI3K/AKT/GSK-3ß/TTBK1 pathway in type 2 diabetic (T2D) rat model. T2D was induced by administration of a high-fat diet for 10 weeks, then injection of a single dose of streptozotocin (STZ); treatment was started with either pramlintide (200 µg/kg/day sc) or liraglutide (0.6 mg/kg/day sc) for 6 weeks in addition to the HFD. At the end of the study, cognitive functions were assessed by novel object recognition and T-maze tests. Then, rats were sacrificed for biochemical and histological assessment of the hippocampal tissue. Both pramlintide and liraglutide treatment revealed equally adequate control of diabetes, prevented the decline in memory function, and increased PI3K/AKT expression while decreasing GSK-3ß/TTBK1 expression; however, liraglutide significantly decreased the number of Tau positive cells better than pramlintide did. This study confirmed that pramlintide and liraglutide are promising antidiabetic medications that could prevent associated cognitive disorders in different mechanisms.

Asperosaponin VI facilitates the regeneration of skeletal muscle injury by suppressing GSK-3ß-mediated cell apoptosis.

Asperosaponin VI (ASA VI) is a bioactive triterpenoid saponin extracted from Diptychus roots, of Diptyl, and has previously shown protective functions in rheumatoid arthritis and sepsis. This study investigates the effects and molecular mechanisms of ASA VI on skeletal muscle regeneration in a cardiotoxin (CTX)-induced skeletal muscle injury mouse model. Mice were subjected to CTX-induced injury in the tibialis anterior and C2C12 myotubes were treated with CTX. Muscle fiber histology was analyzed at 7 and 14 days postinjury. Apoptosis and autophagy-related protein expression were evaluated t s by Western blot, and muscle regeneration markers were quantified by quantitative polymerase chain reaction. Docking studies, cell viability assessments, and glycogen synthase kinase-3ß (GSK-3ß) activation analyses were performed to elucidate the mechanism. ASA VI was observed to improve muscle interstitial fibrosis, remodeling, and performance in CTX-treated mice, thereby increased skeletal muscle size, weight, and locomotion. Furthermore, ASA VI modulated the expression of apoptosis and autophagy-related proteins through GSK-3ß inhibition and activated the transcription of regeneration genes. Our results suggest that ASA VI mitigates skeletal muscle injury by modulating apoptosis and autophagy via GSK-3ß signaling and promotes regeneration, thus presenting a probable therapeutic agent for skeletal muscle injury.

Gastrodin ameliorates synaptic impairment, mitochondrial dysfunction and oxidative stress in N2a/APP cells.

Alzheimer's disease is characterized by abnormal ß-amyloid and tau accumulation, mitochondrial dysfunction, oxidative stress, and synaptic dysfunction. Here, we aimed to assess the mechanisms and signalling pathways in the neuroprotective effect of gastrodin, a phenolic glycoside, on murine neuroblastoma N2a cells expressing human Swedish mutant APP (N2a/APP). We found that gastrodin increased the levels of presynaptic-SNAP, synaptophysin, and postsynaptic-PSD95 and reduced phospho-tau Ser396, APP and Aß1-42 levels in N2a/APP cells. Gastrodin treatment reduced reactive oxygen species generation, lipid peroxidation, mitochondrial fragmentation and DNA oxidation; restored mitochondrial membrane potential and intracellular ATP production. Upregulated phospho-GSK-3ß and reduced phospho-ERK and phospho-JNK were involved in the protective effect of gastrodin. In conclusion, we demonstrated the neuroprotective effect of gastrodin in the N2a/APP cell line by ameliorating the impairment on synaptic and mitochondrial function, reducing tau phosphorylation, Aß1-42 levels as well as reactive oxygen species generation. These results provide new mechanistic insights into the potential effect of gastrodin in the treatment of Alzheimer's disease.

9-Butyl-Harmol Exerts Antiviral Activity against Newcastle Disease Virus through Targeting GSK-3ß and HSP90ß.

The paramyxoviruses represent a large family of human and animal pathogens that cause significant health and economic burdens worldwide. However, there are no available drugs against the virus. ß-carboline alkaloids are a family of naturally occurring and synthetic products with outstanding antiviral activities. Here, we examined the antiviral effect of a series of ß-carboline derivatives against several paramyxoviruses, including Newcastle disease virus (NDV), peste des petits ruminants virus (PPRV), and canine distemper virus (CDV). Among these derivatives, 9-butyl-harmol was identified as an effective antiviral agent against these paramyxoviruses. Further, a genome-wide transcriptome analysis in combination with target validation strategies reveals a unique antiviral mechanism of 9-butyl-harmol through the targeting of GSK-3ß and HSP90ß. On one hand, NDV infection blocks the Wnt/ß-catenin pathway to suppress the host immune response. 9-butyl-harmol targeting GSK-3ß dramatically activates the Wnt/ß-catenin pathway, which results in the boosting of a robust immune response. On the other hand, NDV proliferation depends on the activity of HSP90. The L protein, but not the NP protein or the P protein, is proven to be a client protein of HSP90ß, rather than HSP90α. 9-butyl-harmol targeting HSP90ß decreases the stability of the NDV L protein. Our findings identify 9-butyl-harmol as a potential antiviral agent, provide mechanistic insights into the antiviral mechanism of 9-butyl-harmol, and illustrate the role of ß-catenin and HSP90 during NDV infection. IMPORTANCE Paramyxoviruses cause devastating impacts on health and the economy worldwide. However, there are no suitable drugs with which to counteract the viruses. We determined that 9-butyl-harmol could serve as a potential antiviral agent against paramyxoviruses. Until now, the antiviral mechanism of ß-carboline derivatives against RNA viruses has rarely been studied. Here, we found that 9-butyl-harmol exerts dual mechanisms of antiviral action, with its antiviral activities being mediated by two targets: GSK-3ß and HSP90ß. Correspondingly, the interaction between NDV infection and the Wnt/ß-catenin pathway or HSP90 is demonstrated in this study. Taken together, our findings shed light on the development of antiviral agents against paramyxoviruses, based on the ß-carboline scaffold. These results present mechanistic insights into the polypharmacology of 9-butyl-harmol. Understanding this mechanism also deepens the host-virus interaction and reveals new drug targets for anti-paramyxoviruses.

An in-silico approach - molecular docking analysis of flavonoids against GSK-3ß and TNF-α targets in Alzheimer's disease.

INTRODUCTION: Drug development for Alzheimer's disease has one of the greatest failure rates of any therapeutic field and AD is still incurable. Glycogen synthase kinase-3ß is a critical enzyme implicated in the pathogenesis of AD, particularly in the hyperphosphorylation of tau protein, which leads to the formation of neurofibrillary tangles. TNF-α also plays a significant role in the pathogenesis of Alzheimer's disease by promoting neuroinflammation, contributing to the formation of amyloid plaques and neurofibrillary tangles, impairing synaptic function, and disrupting the balance of neurotrophic factors. Phytomedicine has numerous advantages over synthetic medications, acting multiple mode of action, including being less toxic and having fewer adverse effects. Flavonoids act as a promising therapeutic target for treating Alzheimer's disease. The present work investigates the anti-AD potentials of 35 flavonoids for the inhibition of GSK-3ß and TNF-α. METHODS: The physicochemical, pharmacokinetic parameters, toxicity profile and drug-likeliness of the selected 35 flavonoids were predicted using SwissADME & OSIRIS data Warrier property explorer web tool. All flavonoids were selected for docking studies on GSK-3ß and TNF-α protein using Autodock 4.2.1. RESULTS: The predictions of this study suggested that among the selected 35 flavonoids, Top 3 flavonoids, such as Epicatechin gallate -10.93 kcal/mol, Fisetin -9.44 kcal/mol and Eriodictyol -8.54 kcal/mol for GSK-3ß targets. TNF-α Fisetin -11.52 kcal/mol, Sterubin -10.87 kcal/mol, Biochainin A -10.69 kcal/mol were compared with standard drug donepezil. CONCLUSION: Therefore, these flavonoids could be utilized as possible leads for the structure-based design in the advancement of new, strong Anti-Alzheimer's agents. However, more invitro and invivo analyses are required to finally confirm the outcomes of this research.

The SIRT3/GSK-3ß/GLUT4 axis might be involved in maternal hypoxia-induced skeletal muscle insulin resistance in old male rat offspring.

Maternal hypoxia is strongly linked to insulin resistance (IR) in adult offspring, and altered insulin signaling for muscle glucose uptake is thought to play a central role. However, whether the SIRT3/GSK-3ß/GLUT4 axis is involved in maternal hypoxia-induced skeletal muscle IR in old male rat offspring has not been investigated. Maternal hypoxia was established from Days 5 to 21 of pregnancy by continuous infusion of nitrogen and air. The biochemical parameters and levels of key insulin signaling molecules of old male rat offspring were determined through a series of experiments. Compared to the control (Ctrl) old male rat offspring group, the hypoxic (HY) group exhibited elevated fasting blood glucose (FBG) (∼30%), fasting blood insulin (FBI) (∼35%), total triglycerides (TGs), and low-density lipoprotein cholesterol (LDL-C), as well as results showing impairment in the glucose tolerance test (GTT) and insulin tolerance test (ITT). In addition, hematoxylin-eosin (HE) staining and transmission electron microscopy (TEM) revealed impaired cellular structures and mitochondria in the longitudinal sections of skeletal muscle from HY group mice, which might be associated with decreased SIRT3 expression. Furthermore, the expression of insulin signaling molecules, such as GSK-3ß and GLUT4, was also altered. In conclusion, the present results indicate that the SIRT3/GSK-3ß/GLUT4 axis might be involved in maternal hypoxia-induced skeletal muscle IR in old male rat offspring.

GSK-3ß/ß-catenin pathway plays crucial roles in the regulation of NK cell cytotoxicity against myeloma cells.

The plasma cell malignancy, multiple myeloma (MM), has significantly improved by the application of new drugs and autologous hematopoietic stem cell transplantation. However, MM remains incurable. A number of studies have revealed an anti-MM effect of natural killer (NK) cells; however, their clinical efficacy is limited. Furthermore, glycogen synthase kinase (GSK)-3ß inhibitors show an antitumor function. In this study, we aimed to evaluate the potential roles of a GSK-3ß inhibitor (TWS119) in the regulation of NK cell cytotoxicity against MM. Our results showed that, in the presence of TWS119, the NK cell line, NK-92, and in vitro-expanded primary NK cells exhibited a significantly higher degranulation activity, expression of activating receptors, cellular cytotoxicity, and cytokine secretion when they were exposed to MM cells. Mechanistic studies indicated that TWS119 treatment markedly upregulated RAB27A expression, a key molecule for NK cell degranulation, and induced the colocalization of ß-catenin with NF-κB in the nucleus of NK cells. More importantly, GSK-3ß inhibition combined with the adoptive transfer of TWS119-treated NK-92 cells significantly reduced tumor volume and prolonged the survival time of myeloma-bearing mice. In summary, our novel findings suggest that targeting GSK-3ß through the activation of ß-catenin/NF-κB pathway may be an important approach to improve therapeutic efficacy of NK cell transfusion for MM.

Design, synthesis and biological evaluation of thieno[3,2-c]pyrazol-urea derivatives as potent glycogen synthase kinase 3ß inhibitors based on the DFG-out conformation.

Glycogen synthase kinase 3ß (GSK-3ß) is a potential therapeutic target for the treatment of a variety of human diseases. Here, we report the design and synthesis of a series of thieno[3,2-c]pyrazol-urea derivatives and evaluation of their GSK-3ß inhibitory activity. Among these analogues, the compound without substitution on terminal phenyl ring (3a) was found to be the most potent GSK-3ß inhibitor with an IC50 of 74.4 nM, while substitution on the terminal phenyl (3b-3p) led to decreased potency, independent of the position, size, or electronic properties of the substituents. Kinase selectivity assay revealed that 3a showed good selectivity over a panel of kinases, but was less selective over CDK1, CDK2 and CDK5. Additionally, the pharmacological properties of the synthesized compounds were investigated computationally by the SwissADME and the results showed that most of the compounds have good ADME profiles.

Structure-activity relationship of dual inhibitors containing maleimide and imidazole motifs against glutaminyl cyclase and glycogen synthase kinase-3ß.

Alzheimer's disease (AD) is a major cause of dementia and one of the most common chronic diseases affecting the aging population. Because AD is considered a public health priority, there is a critical need to discover novel and effective agents for the treatment of this condition. In view of the known contribution of up-regulated glutaminyl cyclase (QC) and glycogen synthase kinase-3ß (GSK-3ß) to the initiation of AD, we previously evaluated a series of dual inhibitors containing maleimide and imidazole motifs as potential anti-AD agents. Here, we assessed another series of hybrids containing maleimide and imidazole motifs to gain an in-depth understanding of the structure-activity relationship (SAR). Based on the primary screening, the introduction of 5-methyl imidazole at one side of the molecule did not enhance the QC-specific inhibitory activity of these hybrids (2, IC50 = 1.22 µM), although the potency was increased by 2' substitution on the maleimide motif at the other side of the molecule. Interestingly, compounds containing 5-methyl imidazole exhibited stronger GSK-3ß-specific inhibitory activity (2, IC50 = 0.0021 µM), and the electron-withdrawing group and 2' and 3' substitution were favorable. Further investigation of substitutions on the maleimide motif in compounds 14-35 revealed that QC-specific inhibition in the presence of piperidine was improved by introduction of a methoxy group (R2). Increasing the linker length and introduction of a methoxy group (R2) also increased the GSK-3ß-specific inhibitory potency. These findings were further confirmed by molecular docking analysis of 33 and 24 with QC and GSK-3ß. Overall, these hybrids exhibited enhanced inhibitory potency against both QC and GSK-3ß, highlighting an important strategy for improving the potency of hybrids as dual-targeting anti-AD agents.

Cordycepin inhibits kidney injury by regulating GSK-3ß-mediated Nrf2 activation.

We explored the role and mechanism of cordycepin (COR) in inhibiting kidney injury. A mouse model of kidney injury was established using cisplatin (CDDP), and the kidney function, histopathology, and ferroptosis indices in mice were detected after intervening with COR. The targets of COR-ferroptosis-kidney injury were analyzed by network pharmacology, based on which the association between glycogen synthase kinase-3 beta (GSK-3ß) and COR was determined. HK-2 cells were cultured in vitro and treated separately with ferroptosis inducers erastin and CDDP. After the COR intervention, the level of ferroptosis was monitored. In vitro experiments found that COR could inhibit ferroptosis and CDDP-induced kidney injury. Network pharmacological analysis revealed that GSK-3ß was the target of COR. After inhibiting GSK-3ß expression, COR could not further inhibit the occurrence of ferroptosis. In vitro results also indicated that COR could inhibit ferroptosis in HK-2 cells. According to our findings, COR can ameliorate CDDP-induced kidney injury through GSK-3ß-mediated ferroptosis signaling. We identify new pharmacological effect and target for COR, the major component of Cordyceps sinensis.

ADAMDEC1 induces EMT and promotes colorectal cancer cells metastasis by enhancing Wnt/ß-catenin signaling via negative modulation of GSK-3ß.

Colorectal cancer (CRC) is a highly invasive malignant tumor with pronounced proliferation capacity and is prone to epithelial-mesenchymal transition (EMT) and subsequent metastasis. A disintegrin and metalloproteinase domain-like decysin 1 (ADAMDEC1) is a proteolytically active metzincin metalloprotease that is involved in extracellular matrix remodeling, cell adhesion, invasion, and migration. However, the effects of ADAMDEC1 on CRC are unclear. This study was conducted to investigate the expression and biological role of ADAMDEC1 in CRC. We found that ADAMDEC1 was differentially expressed in CRC. Further, ADAMDEC1 was found to enhance CRC proliferation, migration, and invasion while inhibiting apoptosis. Exogenous ADAMDEC1 overexpression elicited EMT in CRC cells, as evidenced by alterations in E-cadherin, N-cadherin, and vimentin expression. In ADAMDEC1 knockdown or ADAMDEC1 overexpressed CRC cells, the western blotting analysis revealed that Wnt/ß-catenin signaling pathway-related proteins were down-regulated or up-regulated. Furthermore, an inhibitor of the Wnt/ß-catenin pathway (FH535) partially negated the effect of ADAMDEC1 overexpression on EMT and CRC cell proliferation. Further mechanistic research suggested that ADAMDEC1 knockdown may upregulate GSK-3ß and inactivate the Wnt/ß-catenin pathway, accompanied by suppressing the expression of ß-catenin. Additionally, the blocker of GSK-3ß (CHIR-99021) markedly abolished the inhibitory effect of ADAMDEC1 knockdown on Wnt/ß-catenin signaling. Our results indicate that ADAMDEC1 promotes CRC metastasis by negatively regulating GSK-3ß, activating the Wnt/ß-catenin signaling pathway, and inducing EMT, presenting its potential as a therapeutic target for the treatment of metastatic CRC.

Design, synthesis, and biological evaluation of tetrahydropyrimidine analogue as GSK-3ß/Aß aggregation inhibitor and anti-Alzheimer's agent.

The complex nature of Alzheimer's disease (AD) etiopathology is among the principal hurdles to developing effective anti-Alzheimer agents. Tau pathology and Amyloid-ß (Aß) accumulation are hallmarks and validated therapeutic strategies of AD. GSK-3ß is a serine/threonine kinase involved in tau phosphorylation. Its excessive activity also contributes to the production of Aß plaques, making GSK-3ß an attractive AD target. Taking this into account, In this article, we outline the design, synthesis, and biological validation of a focused library of 1,2,3,4-tetrahydropyrimidine based derivatives as inhibitors of GSK-3ß, tau phosphorylation, and Aß accumulation. The inhibitory activity of forty nine synthetic compounds was tested against GSK-3ß and other AD-relevant kinases. The kinetic experiments revealed the mode of GSK-3ß inhibition by the most potent compound 44. The in- vitro drug metabolism and pharmacokinetic studies were thereafter performed. The anti-aggregation activity of the most potent GSK-3ß inhibitor was tested using AD transgenic Caenorhabditis elegans (C. elegans) strain CL2006 for quantification of Aß plaques and BR5706 C. elegans strain for tau pathology evaluation. We then evaluated the blood-brain barrier permeability and got promising results. Therefore, we present compound 44 as a potential ATP-competitive GSK-3ß inhibitor with good metabolism and pharmacokinetic profile, anti-aggregation properties for amyloid beta protein, and reduction in tau-phosphorylation levels. We recommend more investigation into compound 44-based small molecules as possible targets for AD disease-modifying treatments.

Design, synthesis, antineoplastic activity of new pyrazolo[3,4-d]pyrimidine derivatives as dual CDK2/GSK3ß kinase inhibitors; molecular docking study, and ADME prediction.

In the current study, novel pyrazolo[3,4-d]pyrimidine derivatives 5a-h were designed and synthesized as targeted anti-cancer agents through dual CDK2/GSK-3ß inhibition. The designed compounds demonstrated moderate to potent activity on the evaluated cancer cell lines (MCF-7 and T-47D). Compounds 5c and 5 g showed the most promising cytotoxic activity against the tested cell lines surpassing that of the used reference standard; staurosporine. On the other hand, both compounds showed good safety and tolerability on normal fibroblast cell line (MCR5). The final compounds 5c and 5 g showed a promising dual CDK2/GSK-3ß inhibitory activity with IC50 of 0.244 and 0.128 µM, respectively, against CDK2, and IC50 of 0.317 and 0.160 µM, respectively, against GSK-3ß. Investigating the effect of compounds 5c and 5 g on CDK2 and GSK-3ß downstream cascades showed that they reduced the relative cellular content of phosphorylated RB1 and ß-catenin compared to that in the untreated MCF-7 cells. Moreover, compounds 5c and 5 g showed a reasonable selective inhibition against the target kinases CDK2/GSK-3ß in comparison to a set of seven off-target kinases. Furthermore, the most potent compound 5 g caused cell cycle arrest at the S phase in MCF-7 cells preventing the cells' progression to G2/M phase inducing cell apoptosis. Molecular docking studies showed that the final pyrazolo[3,4-d]pyrimidine derivatives have analogous binding modes in the target kinases interacting with the hinge region key amino acids. Molecular dynamics simulations confirmed the predicted binding mode by molecular docking. Moreover, in silico predictions indicated their favorable physicochemical and pharmacokinetic properties in addition to their promising cytotoxic activity.

GSK-3ß orchestrates the inhibitory innervation of adult-born dentate granule cells in vivo.

Adult hippocampal neurogenesis enhances brain plasticity and contributes to the cognitive reserve during aging. Adult hippocampal neurogenesis is impaired in neurological disorders, yet the molecular mechanisms regulating the maturation and synaptic integration of new neurons have not been fully elucidated. GABA is a master regulator of adult and developmental neurogenesis. Here we engineered a novel retrovirus encoding the fusion protein Gephyrin:GFP to longitudinally study the formation and maturation of inhibitory synapses during adult hippocampal neurogenesis in vivo. Our data reveal the early assembly of inhibitory postsynaptic densities at 1 week of cell age. Glycogen synthase kinase 3 Beta (GSK-3ß) emerges as a key regulator of inhibitory synapse formation and maturation during adult hippocampal neurogenesis. GSK-3ß-overexpressing newborn neurons show an increased number and altered size of Gephyrin+ postsynaptic clusters, enhanced miniature inhibitory postsynaptic currents, shorter and distanced axon initial segments, reduced synaptic output at the CA3 and CA2 hippocampal regions, and impaired pattern separation. Moreover, GSK-3ß overexpression triggers a depletion of Parvalbumin+ interneuron perineuronal nets. These alterations might be relevant in the context of neurological diseases in which the activity of GSK-3ß is dysregulated.

Unraveling the neuroprotective mechanisms of naltrexone against aluminum-induced neurotoxicity.

Aluminum (Al) is a known neurotoxic trace element linked to Alzheimer's disease (AD). Naltrexone, an opioid antagonist, has shown promising effects in reducing neuroinflammation at lower doses than those prescribed for addiction. This study aimed to determine the neuroprotective effects of naltrexone on Al-induced neurotoxicity in an in vitro AD model. The SH-SY5Y cells were first cultivated in a standard growth medium. Subsequently, the cells were induced to differentiate by decreasing the concentration of fetal bovine serum and introducing retinoic acid (RA) into the culture media. Subsequently, the inclusion of brain-derived neurotrophic factor (BDNF) was implemented in conjunction with RA. The process of differentiation was concluded on the seventh day. Study groups (n = 3) were designed as the control group, naltrexone group, Al group, Al-Nal group, Alzheimer' model (AD) group, Alzheimer model + Al-exposed group (AD-Al), Alzheimer model + Nal applied group (AD-Nal) and Alzheimer model + Al-exposed + Nal applied group (AD-Al-Nal). Hyperphosphorylated Tau protein as the specific marker of AD was measured in all groups. Glycogen synthase kinase-3 (GSK-3)ß, Protein phosphatase 2A (PP2A), Akt and Wnt signaling pathways were analyzed comparatively. In addition, oxidative stress parameters (total antioxidant capacity, lipid peroxidase, protein carbonyl and reactive oxygen species) were measured comparatively in the study groups. The results showed that naltrexone reduced hyperphosphorylated tau protein levels by regulating GSK-3ß, PP2A, Akt and Wnt signaling. Also, exposure to naltrexone decreased oxidative stress parameters. Based on these results, naltrexone shows promise as a potential therapy for AD, subject to additional clinical assessments.

Discovery of novel harmine derivatives as GSK-3ß/DYRK1A dual inhibitors for Alzheimer's disease treatment.

Multitarget-directed ligands (MTDLs) have recently attracted significant interest due to their superior effectiveness in multifactorial Alzheimer's disease (AD). Combined inhibition of two important AD targets, glycogen synthase kinase-3ß (GSK-3ß) and dual-specificity tyrosine phosphorylation-regulated kinase 1A (DYRK1A), may be a breakthrough in the treatment of AD. Based on our previous work, we have designed and synthesized a series of novel harmine derivatives, investigated their inhibition of GSK-3ß and DYRK1A, and evaluated a variety of biological activities. The results of the experiments showed that most of these compounds exhibited good activity against GSK-3ß and DYRK1A in vitro. ZLQH-5 was selected as the best compound due to the most potent inhibitory effect against GSK-3ß and DYRK1A. Molecular docking studies demonstrated that ZLQH-5 could form stable interactions with the ATP binding pocket of GSK-3ß and DYRK1A. In addition, ZLQH-5 showed low cytotoxicity against SH-SY5Y and HL-7702, good blood-brain barrier permeability, and favorable pharmacokinetic properties. More importantly, ZLQH-5 also attenuated the tau hyperphosphorylation in the okadaic acid SH-SY5Y cell model. These results indicated that ZLQH-5 could be a promising dual-target drug candidate for the treatment of AD.

Beyond Amyloid: A Machine Learning-Driven Approach Reveals Properties of Potent GSK-3ß Inhibitors Targeting Neurofibrillary Tangles.

Current treatments for Alzheimer's disease (AD) focus on slowing memory and cognitive decline, but none offer curative outcomes. This study aims to explore and curate the common properties of active, drug-like molecules that modulate glycogen synthase kinase 3ß (GSK-3ß), a well-documented kinase with increased activity in tau hyperphosphorylation and neurofibrillary tangles-hallmarks of AD pathology. Leveraging quantitative structure-activity relationship (QSAR) data from the PubChem and ChEMBL databases, we employed seven machine learning models: logistic regression (LogR), k-nearest neighbors (KNN), random forest (RF), support vector machine (SVM), extreme gradient boosting (XGB), neural networks (NNs), and ensemble majority voting. Our goal was to correctly predict active and inactive compounds that inhibit GSK-3ß activity and identify their key properties. Among the six individual models, the NN demonstrated the highest performance with a 79% AUC-ROC on unbalanced external validation data, while the SVM model was superior in accurately classifying the compounds. The SVM and RF models surpassed NN in terms of Kappa values, and the ensemble majority voting model demonstrated slightly better accuracy to the NN on the external validation data. Feature importance analysis revealed that hydrogen bonds, phenol groups, and specific electronic characteristics are important features of molecular descriptors that positively correlate with active GSK-3ß inhibition. Conversely, structural features like imidazole rings, sulfides, and methoxy groups showed a negative correlation. Our study highlights the significance of structural, electronic, and physicochemical descriptors in screening active candidates against GSK-3ß. These predictive features could prove useful in therapeutic strategies to understand the important properties of GSK-3ß candidate inhibitors that may potentially benefit non-amyloid-based AD treatments targeting neurofibrillary tangles.