Glycogen synthase kinase 3: an emerging therapeutic target

Acetoacetate and d- and l-β-hydroxybutyrate have distinct effects on basal and insulin-stimulated glucose uptake in L6 skeletal muscle cells

Ketone bodies (acetoacetate and β-hydroxybutyrate) are oxidized in skeletal muscle mainly during fasting as an alternative source of energy to glucose. Previous studies suggest that there is a negative relationship between increased muscle ketolysis and muscle glucose metabolism in mice with obesity and/or type 2 diabetes. Therefore, we investigated the connection between increased ketone body exposure and muscle glucose metabolism by measuring the effect of a 3-h exposure to ketone bodies on glucose uptake in differentiated L6 myotubes. We showed that exposure to acetoacetate at a typical concentration (0.2 mM) resulted in increased basal glucose uptake in L6 myotubes, which was dependent on increased membrane glucose transporter type 4 (GLUT4) translocation. Basal and insulin-stimulated glucose uptake was also increased with a concentration of acetoacetate reflective of diabetic ketoacidosis or a ketogenic diet (1 mM). We found that β-hydroxybutyrate had a variable effect on basal glucose uptake: a racemic mixture of the two β-hydroxybutyrate enantiomers (d and l) appeared to decrease basal glucose uptake, while 3 mM d-β-hydroxybutyrate alone increased basal glucose uptake. However, the effects of the ketone bodies individually were not observed when acetoacetate was present in combination with β-hydroxybutyrate. These results provide insight that will help elucidate the effect of ketone bodies in the context of specific metabolic diseases and nutritional states (e.g., type 2 diabetes and ketogenic diets).NEW & NOTEWORTHY A limited number of studies investigate the effect of ketone bodies at concentrations reflective of both typical fasting and ketoacidosis. We tested a mix of physiologically relevant concentrations of ketone bodies, which allowed us to highlight the differential effects of d- and l-β-hydroxybutyrate and acetoacetate on skeletal muscle cell glucose uptake. Our findings will assist in better understanding the mechanisms that contribute to muscle insulin resistance and provide guidance on recommendations regarding ketogenic diets.

Therapeutic implications of glycogen synthase kinase-3β in Alzheimer's disease: a novel therapeutic target

Alzheimer's disease (AD) is an extremely popular neurodegenerative condition associated with dementia, responsible for around 70% of the cases. There are presently 50 million people living with dementia in the world, but this number is anticipated to increase to 152 million by 2050, posing a substantial socioeconomic encumbrance. Despite extensive research, the precise mechanisms that cause AD remain unidentified, and currently, no therapy is available. Numerous signalling paths related to AD neuropathology, including glycogen synthase kinase 3-β (GSK-3β), have been investigated as potential targets for the treatment of AD in current years.GSK-3β is a proline-directed serine/threonine kinase that is linked to a variety of biological activities, comprising glycogen metabolism to gene transcription. GSK-3β is also involved in the pathophysiology of sporadic as well as familial types of AD, which has led to the development of the GSK3 theory of AD. GSK-3β is a critical performer in the pathology of AD because dysregulation of this kinase affects all the main symbols of the disease such as amyloid formation, tau phosphorylation, neurogenesis and synaptic and memory function. The current review highlights present-day knowledge of GSK-3β-related neurobiology, focusing on its role in AD pathogenesis signalling pathways. It also explores the possibility of targeting GSK-3β for the management of AD and offers an overview of the present research work in preclinical and clinical studies to produce GSK-3β inhibitors.

Neuropharmacological insights into Gardenia jasminoides Ellis: Harnessing therapeutic potential for central nervous system disorders

BACKGROUND

In China, Gardenia jasminoides Ellis (GJE) has a longstanding history of application. The Ministry of Health has listed it as one of the first pharmaceutical or food resources. In ethnic, traditional, and folk medicine, GJE has been used to treat fever and cold and relieve nervous anxiety. Recent studies have confirmed the significant efficacy of GJE for treating central nervous system (CNS) disorders, including Alzheimer's disease, Parkinson's disease, and major depressive disorder; however, GJE has not been systematically evaluated.

PURPOSE

This research systematically summarizes global studies on the use of GJE for treating CNS disorders and explores the potential applications and underlying mechanisms via intestinal flora analysis and network pharmacology, aiming to establish a scientific basis for innovative CNS disorder treatment with GJE.

METHODS

The PRISMA guidelines were used, and electronic databases such as the Web of Science, PubMed, and China National Knowledge Infrastructure were searched using the following search terms: "Gardenia jasminoides Ellis" with "central nervous system disease," "neuroprotection," "Alzheimer's disease," "Parkinson's disease," "ischemic stroke," "Epilepsy," and "major depressive disorder." The published literature up to September 2023 was searched to obtain relevant information on the application of GJE for treating CNS disorders.

RESULTS

There has been an increase in research on the material formulation and mechanisms of action of GJE for treating CNS disorders, with marked effects on CNS disorder treatment in different countries and regions. We summarized the research results related to the role of GJE in vitro and in vivo via multitargeted interventions in response to the complex mechanisms of action of CNS disorders.

CONCLUSION

We systematically reviewed the research progress on traditional treatment for GJE and preclinical mechanisms of CNS disorders and explored the potential of optimizing network pharmacology strategies and intestinal flora analysis to elucidate the mechanisms of action of GJE. The remarkable therapeutic efficacy of GJE, an important resource in traditional medicine, has been well documented in the literature, highlighting its significant medicinal potential.

GSK3β: A ray of hope for the treatment of diabetic kidney disease

Diabetic kidney disease (DKD), a major microvascular complication of diabetes, is characterized by its complex pathogenesis, high risk of chronic renal failure, and lack of effective diagnosis and treatment methods. GSK3β (glycogen synthase kinase 3β), a highly conserved threonine/serine kinase, was found to activate glycogen synthase. As a key molecule of the glucose metabolism pathway, GSK3β participates in a variety of cellular activities and plays a pivotal role in multiple diseases. However, these effects are not only mediated by affecting glucose metabolism. This review elaborates on the role of GSK3β in DKD and its damage mechanism in different intrinsic renal cells. GSK3β is also a biomarker indicating the progression of DKD. Finally, the protective effects of GSK3β inhibitors on DKD are also discussed.

Therapies for Tau-associated neurodegenerative disorders: targeting molecules, synapses, and cells

Advances in experimental and computational technologies continue to grow rapidly to provide novel avenues for the treatment of neurodegenerative disorders. Despite this, there remain only a handful of drugs that have shown success in late-stage clinical trials for Tau-associated neurodegenerative disorders. The most commonly prescribed treatments are symptomatic treatments such as cholinesterase inhibitors and N-methyl-D-aspartate receptor blockers that were approved for use in Alzheimer's disease. As diagnostic screening can detect disorders at earlier time points, the field needs pre-symptomatic treatments that can prevent, or significantly delay the progression of these disorders (Koychev et al., 2019). These approaches may be different from late-stage treatments that may help to ameliorate symptoms and slow progression once symptoms have become more advanced should early diagnostic screening fail. This mini-review will highlight five key avenues of academic and industrial research for identifying therapeutic strategies to treat Tau-associated neurodegenerative disorders. These avenues include investigating (1) the broad class of chemicals termed "small molecules"; (2) adaptive immunity through both passive and active antibody treatments; (3) innate immunity with an emphasis on microglial modulation; (4) synaptic compartments with the view that Tau-associated neurodegenerative disorders are synaptopathies. Although this mini-review will focus on Alzheimer's disease due to its prevalence, it will also argue the need to target other tauopathies, as through understanding Alzheimer's disease as a Tau-associated neurodegenerative disorder, we may be able to generalize treatment options. For this reason, added detail linking back specifically to Tau protein as a direct therapeutic target will be added to each topic.

A randomized controlled trial of Vitamin D supplementation in Iranian patients with schizophrenia: Effects on serum levels of glycogen synthase kinase-3β and symptom severity

BACKGROUND

Growing evidence has shown that hypovitaminosis D is a risk factor for developing schizophrenia and comorbid conditions. Therefore, this study aimed to examine the effect of vitamin D supplementation on serum levels of vitamin D, metabolic factors related to insulin resistance (IR) and the severity of the disorder in patients with schizophrenia.

METHODS

Forty-eight chronic male patients with schizophrenia with vitamin D deficiency (≤20 ng/mL= (≤50 nmol/l) were selected and randomly assigned to vitamin D treatment and placebo groups. Subjects were supplemented for 8 weeks with vitamin D (2000 IU/day) or placebo.

RESULTS

Within-group comparison revealed that the vitamin D group had a significant reduction in waist circumference, Positive and Negative Syndrome Scale - total score (PANSS-TS), and glycogen synthase kinase 3 beta (GSK-3β) levels (P = .022, P = <.001 and P = .013, respectively). On the other hand, the placebo group showed a significant increase in the level of fasting serum insulin and Homeostatic Model Assessment of Insulin Resistance (HOMA-IR) (P = .003 and P = .003). The between-group comparison showed a significant difference in terms of PANSS-TS, GSK-3β, fasting serum insulin (FSI), and HOMA-IR (P = .022, P = .048, P = .013 and P = .014 respectively).

CONCLUSIONS

Among vitamin D deficient patients with schizophrenia, vitamin D supplementation may affect GSK-3 β, an important biomarker in schizophrenia and insulin resistance. In addition, vitamin D supplementation in such patients may reduce the disorder's symptom severity.

Role of GSK-3β Inhibitors: New Promises and Opportunities for Alzheimer's Disease

Glycogen synthase kinase-3 (GSK-3) was discovered to be a multifunctional enzyme involved in a wide variety of biological processes, including early embryo formation, oncogenesis, as well cell death in neurodegenerative diseases. Several critical cellular processes in the brain are regulated by the GSK-3β, serving as a central switch in the signaling pathways. Dysregulation of GSK-3β kinase has been reported in diabetes, cancer, Alzheimer's disease, schizophrenia, bipolar disorder, inflammation, and Huntington's disease. Thus, GSK-3β is widely regarded as a promising target for therapeutic use. The current review article focuses mainly on Alzheimer's disease, an age-related neurodegenerative brain disorder. GSK-3β activation increases amyloid-beta (Aβ) and the development of neurofibrillary tangles that are involved in the disruption of material transport between axons and dendrites. The drug-binding cavities of GSK-3β are explored, and different existing classes of GSK-3β inhibitors are explained in this review. Non-ATP competitive inhibitors, such as allosteric inhibitors, can reduce the side effects compared to ATP-competitive inhibitors. Whereas ATP-competitive inhibitors produce disarrangement of the cytoskeleton, neurofibrillary tangles formation, and lead to the death of neurons, etc. This could be because they are binding to a site separate from ATP. Owing to their interaction in particular and special binding sites, allosteric ligands interact with substrates more selectively, which will be beneficial in resolving drug-induced resistance and also helpful in reducing side effects. Hence, in this review, we focussed on the allosteric GSK-3β inhibitors and discussed their futuristic opportunities as anti-Alzheimer's compounds.

TCMBank: bridges between the largest herbal medicines, chemical ingredients, target proteins, and associated diseases with intelligence text mining

Traditional Chinese Medicine (TCM) has long been viewed as a precious source of modern drug discovery. AI-assisted drug discovery (AIDD) has been investigated extensively. However, there are still two challenges in applying AIDD to guide TCM drug discovery: the lack of a large amount of standardized TCM-related information and AIDD is prone to pathological failures in out-of-domain data. We have released TCM Database@Taiwan in 2011, and it has been widely disseminated and used. Now, we developed TCMBank, the largest systematic free TCM database, which is an extension of TCM Database@Taiwan. TCMBank contains 9192 herbs, 61 966 ingredients (unduplicated), 15 179 targets, 32 529 diseases, and their pairwise relationships. By integrating multiple data sources, TCMBank provides 3D structure information of ingredients and provides a standard list and detailed information on herbs, ingredients, targets and diseases. TCMBank has an intelligent document identification module that continuously adds TCM-related information retrieved from the literature in PubChem. In addition, driven by TCMBank big data, we developed an ensemble learning-based drug discovery protocol for identifying potential leads and drug repurposing. We take colorectal cancer and Alzheimer's disease as examples to demonstrate how to accelerate drug discovery by artificial intelligence. Using TCMBank, researchers can view literature-driven relationship mapping between herbs/ingredients and genes/diseases, allowing the understanding of molecular action mechanisms for ingredients and identification of new potentially effective treatments. TCMBank is available at https://TCMBank.CN/.

Targeting Pro-Survival Autophagy Enhanced GSK-3β Inhibition-Induced Apoptosis and Retarded Proliferation in Bladder Cancer Cells

Advanced bladder cancer (BC) (local invasive and/or metastatic) is not curable even with cytotoxic chemotherapy, immune checkpoint inhibitors, and targeted treatment. Targeting GSK-3β is a promising novel approach in advanced BC. The induction of autophagy is a mechanism of secondary resistance to various anticancer treatments. Our objectives are to investigate the synergistic effects of GSK-3β in combination with autophagy inhibitors to evade GSK-3β drug resistance. Small molecule GSK-3β inhibitors and GSK-3β knockdown using siRNA promote the expression of autophagy-related proteins. We further investigated that GSK-3β inhibition induced the nucleus translocation of transcription factor EB (TFEB). Compared to the GSK-3β inhibition alone, its combination with chloroquine (an autophagy inhibitor) significantly reduced BC cell growth. These results suggest that targeting autophagy potentiates GSK-3β inhibition-induced apoptosis and retarded proliferation in BC cells.

Lithium treatment mitigates the diabetogenic effects of chronic cortico-therapy

BACKGROUND AND PURPOSE

Glucocorticoids (GCs) are the main treatment for autoimmune and inflammatory disorders and are also used as immunosuppressive therapy for patients with organ transplantation. However, these treatments have several side effects, including metabolic disorders. Indeed, cortico-therapy may induce insulin resistance, glucose intolerance, disrupted insulin and glucagon secretion, excessive gluconeogenesis, leading to diabetes in susceptible individuals. Recently, lithium has been shown to alleviate deleterious effects of GCs in various diseased conditions.

EXPERIMENTAL APPROACH

In this study, using two rat models of GC-induced metabolic disorders, we investigated the effects of Lithium Chloride (LiCl) in the mitigation of deleterious effects of GCs. Rats were treated either with corticosterone or dexamethasone, and with or without LiCl. Animals were then assessed for glucose tolerance, insulin sensitivity, in vivo and ex vivo glucose-induced insulin secretion and hepatic gluconeogenesis.

KEY RESULTS

We showed that in rats chronically treated with corticosterone, lithium treatment markedly reduced insulin resistance. In addition, in rats treated with dexamethasone, lithium administration improved glucose tolerance, associated with enhanced insulin secretion in vivo. Moreover, liver gluconeogenesis was reduced upon LiCl treatment. The improvement of insulin secretion in vivo appeared to be due to an indirect regulation of β cell function, since the ex vivo assessment of insulin secretion and β cell mass in islets from animals treated with LiCl revealed no difference compared to untreated animals.

CONCLUSION AND IMPLICATIONS

Collectively, our data provide evidences for the beneficial effects of lithium to mitigate the adverse metabolic effects of chronic cortico-therapy.

Restoration of lysosomal acidification rescues autophagy and metabolic dysfunction in non-alcoholic fatty liver disease

Non-alcoholic fatty liver disease (NAFLD) is the most common liver disease in the world. High levels of free fatty acids in the liver impair hepatic lysosomal acidification and reduce autophagic flux. We investigate whether restoration of lysosomal function in NAFLD recovers autophagic flux, mitochondrial function, and insulin sensitivity. Here, we report the synthesis of novel biodegradable acid-activated acidifying nanoparticles (acNPs) as a lysosome targeting treatment to restore lysosomal acidity and autophagy. The acNPs, composed of fluorinated polyesters, remain inactive at plasma pH, and only become activated in lysosomes after endocytosis. Specifically, they degrade at pH of ~6 characteristic of dysfunctional lysosomes, to further acidify and enhance the function of lysosomes. In established in vivo high fat diet mouse models of NAFLD, re-acidification of lysosomes via acNP treatment restores autophagy and mitochondria function to lean, healthy levels. This restoration, concurrent with reversal of fasting hyperglycemia and hepatic steatosis, indicates the potential use of acNPs as a first-in-kind therapeutic for NAFLD.

GSK-3 at the heart of cardiometabolic diseases: Isoform-specific targeting is critical to therapeutic benefit

Glycogen synthase kinase-3 (GSK-3) is a family of serine/threonine kinases. The GSK-3 family has 2 isoforms, GSK-3α and GSK-3β. The GSK-3 isoforms have been shown to play overlapping as well as isoform-specific-unique roles in both, organ homeostasis and the pathogenesis of multiple diseases. In the present review, we will particularly focus on expanding the isoform-specific role of GSK-3 in the pathophysiology of cardiometabolic disorders. We will highlight recent data from our lab that demonstrated the critical role of cardiac fibroblast (CF) GSK-3α in promoting injury-induced myofibroblast transformation, adverse fibrotic remodeling, and deterioration of cardiac function. We will also discuss studies that found the exact opposite role of CF-GSK-3β in cardiac fibrosis. We will review emerging studies with inducible cardiomyocyte (CM)-specific as well as global isoform-specific GSK-3 KOs that demonstrated inhibition of both GSK-3 isoforms provides benefits against obesity-associated cardiometabolic pathologies. The underlying molecular interactions and crosstalk among GSK-3 and other signaling pathways will be discussed. We will briefly review the specificity and limitations of the available small molecule inhibitors targeting GSK-3 and their potential applications to treat metabolic disorders. Finally, we will summarize these findings and offer our perspective on envisioning GSK-3 as a therapeutic target for the management of cardiometabolic diseases.

Glycogen Synthase Kinase-3 Inhibitors Block Morphine-Induced Locomotor Activation, Straub Tail, and Depression of Rearing in Mice Via a Possible Central Action

We investigated morphine-induced Straub's tail reaction (STR) in mice pretreated with or without glycogen synthase kinase-3 (GSK-3) inhibitors (SB216763 and AR-A014418) by using a newly modified, infrared beam sensor-based automated apparatus. Mice treated with a single injection of morphine (30 mg/kg, i.p.) showed a significant STR with a plateau level at a time point of 20 min after morphine challenge. Pretreatment of mice with SB216763 (5 mg/kg, s.c.) or AR-A014418 (3 mg/kg, i.p.) significantly inhibited morphine-induced STR and attenuated the duration of STR in a dose-dependent fashion. In the striatum and the nucleus accumbens, expression of pGSK-3β^Tyr216 but not GSK3β or pGSK-3β^Ser9 was largely but not significantly reduced after treatment with SB216763 (5 mg/kg, s.c.) in combination with/without morphine, indicating that the inhibitory effect of GSK-3 inhibitors on morphine-induced STR and hyperlocomotion might not depend on the direct blockade of GSK-3β function. In constipated mice after morphine challenge (30 mg/kg), the effect of GSK-3 inhibitors on gastrointestinal transit was examined to reveal whether the action of GSK-3 inhibitors on morphine effects was central and/or peripheral. Pretreatment with SB216763 (5 mg/kg) did not block constipation in morphine-injected mice. The mechanism of action seems to be central but not peripheral, although the underlying subcellular mechanism of GSK-3 inhibitors is not clear. Our measurement system is a useful tool for investigating the excitatory effects of morphine in experimental animals.

Type 2 Diabetes Mellitus and Alzheimer's Disease: Shared Molecular Mechanisms and Potential Common Therapeutic Targets

The global prevalence of diabetes mellitus and Alzheimer's disease is increasing alarmingly with the aging of the population. Numerous epidemiological data suggest that there is a strong association between type 2 diabetes and an increased risk of dementia. These diseases are both degenerative and progressive and share common risk factors. The amyloid cascade plays a key role in the pathophysiology of Alzheimer's disease. The accumulation of amyloid beta peptides gradually leads to the hyperphosphorylation of tau proteins, which then form neurofibrillary tangles, resulting in neurodegeneration and cerebral atrophy. In Alzheimer's disease, apart from these processes, the alteration of glucose metabolism and insulin signaling in the brain seems to induce early neuronal loss and the impairment of synaptic plasticity, years before the clinical manifestation of the disease. The large amount of evidence on the existence of insulin resistance in the brain during Alzheimer's disease has led to the description of this disease as "type 3 diabetes". Available animal models have been valuable in the understanding of the relationships between type 2 diabetes and Alzheimer's disease, but to date, the mechanistical links are poorly understood. In this non-exhaustive review, we describe the main molecular mechanisms that may link these two diseases, with an emphasis on impaired insulin and IGF-1 signaling. We also focus on GSK3β and DYRK1A, markers of Alzheimer's disease, which are also closely associated with pancreatic β-cell dysfunction and type 2 diabetes, and thus may represent common therapeutic targets for both diseases.

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

Genetic studies have highlighted microglia as pivotal in orchestrating Alzheimer's disease (AD). Microglia that adhere to Aβ 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 Aβ plaques, accelerating brain pathology and behavioral deficits. SYK deficiency impaired the PI3K-AKT-GSK-3β-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 Aβ 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.

Recent clinical findings on the role of kinase inhibitors in COVID-19 management

The highly pathogenic, novel coronavirus disease (COVID-19) outbreak has emerged as a once-in-a-century pandemic with poor consequences, urgently calling for new therapeutics, cures, and supportive interventions. It has already affected over 250 million people worldwide; thereby, there is a need for novel therapies to alleviate the related complications. There is a paradigm shift in developing drugs and clinical practices to combat COVID-19. Several clinical trials have been performed or are testing diverse pharmacological interventions to alleviate viral load and complications such as cytokine release storm (CRS). Kinase-inhibitors have appeared as potential antiviral agents for COVID-19 patients due to their efficacy against CRS. Combination of kinase inhibitors with other therapies can achieve more efficacy against COVID-19. Based on the pre-clinical trials, kinase inhibitors such as Janus kinase-signal transducer and activator of transcription (JAK/STAT) inhibitors, Brutton's tyrosin kinase (BTK) inhibitors, p38 mitogen-activated protein kinases (p38 MAPK) inhibitors, Glycogen synthase kinase 3 (GSK-3) inhibitors can be a promising strategy against COVID-19. Kinase inhibitors possess crucial pharmacological properties for a successful re-purposing in terms of dual anti-inflammatory and anti-viral effects. This review will address the current clinical evidence and the newest discovery regarding the application of kinase inhibitors in COVID-19. An outlook on ongoing clinical trials (clinicaltrials.gov) and unpublished data is also presented here. Besides, Kinase inhibitors' function on COVID-19-mediated CRS is discussed.

Neuromolecular Etiology of Bipolar Disorder: Possible Therapeutic Targets of Mood Stabilizers

Bipolar disorder is a mental illness that causes extreme mood swings and has a chronic course. However, the mechanism by which mood episodes with completely opposite characteristics appear repeatedly, or a mixture of symptoms appears, in patients with bipolar disorder remains unknown. Therefore, mood stabilizers are indicated only for single mood episodes, such as manic episodes and depressive episodes, and no true mood-stabilizing drugs effective for treating both manic and depressive episodes currently exist. Therefore, in this review, therapeutic targets that facilitate the development of mood stabilizers were examined by reviewing the current understanding of the neuromolecular etiology of bipolar disorder.

GSK-3β Inhibition in Birds Affects Social Behavior and Increases Motor Activity

Glycogen synthase kinase-3 (GSK-3) is a highly conserved serine/threonine protein kinase that plays a central role in a wide variety of cellular processes, cognition and behaviour. In a previous study we showed that its α and β isozymes are highly conserved in vertebrates, however the α gene is missing in birds. This selective loss offers a unique opportunity to study the role of GSK-3β independently. Accordingly, in the present study we aimed to investigate the role of GSK-3β in social behaviour, motivation, and motor activity in zebra finches (Taeniopygia guttata). We did that by selective inhibition of GSK-3β and by using tests that were specifically designed in our laboratory. Our results show that GSK-3β inhibition: 1) Affected social recognition, because the treated birds tended to move closer towards a stranger, unlike the control birds that stood closer to a familiar bird. 2) Caused the treated birds to spend more time in the more middle parts of the cage compared to controls, a behaviour that might indicate anxiety. 3) As the experiment progressed, the treated birds took less time to make a decision where to stand in the cage compared to controls, suggesting an effect on decision-making. 4) Increased in the motor activity of the treated birds compared to the controls, which can be regarded as hyperactivity. 5) Caused the treated birds to pass through a barrier in order to join their flock members faster compared to controls, and regardless of the increase in the level of difficulty, possibly suggesting increased motivation. Our study calls for further investigation, because GSK-3 is well acknowledged as a central player in regulating mood behaviour, cognitive functions, and neuronal viability. Therefore, studying its impact on normal behaviour as we did in the current study, unlike most studies that were done in diseases models, can advance our understanding regarding GSK-3 various roles and can contribute to the discovery and development of effective treatments to repair cognition and behaviour.

Role of Glycogen Synthase Kinase-3 in Interferon-γ-Mediated Immune Hepatitis

Glycogen synthase kinase-3 (GSK-3), a serine/threonine kinase, is a vital glycogen synthase regulator controlling glycogen synthesis, glucose metabolism, and insulin signaling. GSK-3 is widely expressed in different types of cells, and its abundant roles in cellular bioregulation have been speculated. Abnormal GSK-3 activation and inactivation may affect its original bioactivity. Moreover, active and inactive GSK-3 can regulate several cytosolic factors and modulate their diverse cellular functional roles. Studies in experimental liver disease models have illustrated the possible pathological role of GSK-3 in facilitating acute hepatic injury. Pharmacologically targeting GSK-3 is therefore suggested as a therapeutic strategy for liver protection. Furthermore, while the signaling transduction of GSK-3 facilitates proinflammatory interferon (IFN)-γ in vitro and in vivo, the blockade of GSK-3 can be protective, as shown by an IFN-γ-induced immune hepatitis model. In this study, we explored the possible regulation of GSK-3 and the potential relevance of GSK-3 blockade in IFN-γ-mediated immune hepatitis.

CYCLOBUTANES IN SMALL MOLECULE DRUG CANDIDATES

Cyclobutanes are increasingly used in medicinal chemistry in the search for relevant biological properties. Important characteristics of the cyclobutane ring include its unique puckered structure, longer C−C bond lengths, increased C−C π‐character and relative chemical inertness for a highly strained carbocycle. This review will focus on contributions of cyclobutane rings in drug candidates to arrive at favorable properties. Cyclobutanes have been employed for improving multiple factors such as preventing cis/trans‐isomerization by replacing alkenes, replacing larger cyclic systems, increasing metabolic stability, directing key pharmacophore groups, inducing conformational restriction, reducing planarity, as aryl isostere and filling hydrophobic pockets.

Kinases as Potential Therapeutic Targets for Anti-coronaviral Therapy

The global coronavirus disease-19 (COVID-19) has affected more than 140 million and killed more than 3 million people worldwide as of April 20, 2021. The novel human severe acute respiratory syndrome coronavirus-2 (SARS-CoV-2) has been identified as an etiological agent for COVID-19. Several kinases have been proposed as possible mediators of multiple viral infections, including life-threatening coronaviruses like SARS-CoV-1, Middle East syndrome coronavirus (MERS-CoV), and SARS-CoV-2. Viral infections hijack abundant cell signaling pathways, resulting in drastic phosphorylation rewiring in the host and viral proteins. Some kinases play a significant role throughout the viral infection cycle (entry, replication, assembly, and egress), and several of them are involved in the virus-induced hyperinflammatory response that leads to cytokine storm, acute respiratory distress syndrome (ARDS), organ injury, and death. Here, we highlight kinases that are associated with coronavirus infections and their inhibitors with antiviral and potentially anti-inflammatory, cytokine-suppressive, or antifibrotic activity.

Glycogen Synthase Kinase-3 Inhibitors: Preclinical and Clinical Focus on CNS-A Decade Onward

The protein kinase, GSK-3, participates in diverse biological processes and is now recognized a promising drug discovery target in treating multiple pathological conditions. Over the last decade, a range of newly developed GSK-3 inhibitors of diverse chemotypes and inhibition modes has been developed. Even more conspicuous is the dramatic increase in the indications that were tested from mood and behavior disorders, autism and cognitive disabilities, to neurodegeneration, brain injury and pain. Indeed, clinical and pre-clinical studies were largely expanded uncovering new mechanisms and novel insights into the contribution of GSK-3 to neurodegeneration and central nerve system (CNS)-related disorders. In this review we summarize new developments in the field and describe the use of GSK-3 inhibitors in the variety of CNS disorders. This remarkable volume of information being generated undoubtedly reflects the great interest, as well as the intense hope, in developing potent and safe GSK-3 inhibitors in clinical practice.

PROTACs technology for treatment of Alzheimer's disease: Advances and perspectives

Neurodegenerative diseases (NDs) are characteristic with progression of neuron degeneration, resulting in dysfunction of cognition and mobility. Many neurodegenerative diseases are because of proteinopathies that results from unusual protein accumulations and aggregations. The aggregation of misfolded proteins like β-amyloid, α-synuclein, tau, and polyglutamates are hallmarked in Alzheimer's disease (AD), which are undruggable targets, and usually do not respond to conventional small-molecule agents. Therefore, developing novel technology and strategy for reducing the levels of protein aggregates would be critical for treatment of AD. Recently, the emerging proteolysis targeting chimeras (PRPTACs) technology has been significantly considered for artificial and selective degradation of aberrant target proteins. These engineered bifunctional molecules engage target proteins to be degraded by either the cellular degradation machinery in the ubiquitin-proteasome system (UPS) or via the autophagy-lysosome degradation pathway. Although the application of PROTACs technology is preferable than oligonucleotide and antibodies for treatment of NDs, many limitations such as their pharmacokinetic properties, tissue distribution and cell permeabilities, still need to be corrected. Herein, we review the recent advances in PROTACs technology with their limitation for pharmaceutical targeting of aberrant proteins involved in Alzheimer's diseases. We also review therapeutic potential of dysregulated signaling such as PI3K/AKT/mTOR axis for the management of AD.

The GSK-3β/β-Catenin Signaling-Mediated Brain-Derived Neurotrophic Factor Pathway Is Involved in Aluminum-Induced Impairment of Hippocampal LTP In Vivo

The neurotoxic effects of aluminum (Al) are associated with the impairment of synaptic plasticity, the biological basis of learning and memory, the major form of which is long-term potentiation (LTP). The canonical glycogen synthase kinase-3β (GSK-3β)/β-catenin signaling-mediated brain-derived neurotrophic factor (BDNF) pathway has been suggested to play important roles in memory. Thus, Al may affect LTP through this pathway. In this study, a Sprague-Dawley rat model of neurotoxicity was established through intracerebroventricular (i.c.v.) injection of aluminum maltol (Al(mal)₃), which was achieved by preimplantation of a cannula into the lateral ventricle. The rats in the control and Al-treated groups received a daily injection of SB216763, an inhibitor of GSK-3β. Electrophysiology and western blot analysis were used to investigate the regulatory effect of the GSK-3β/β-catenin signaling-mediated BDNF pathway on LTP impairment induced by Al(mal)₃. The results confirmed that i.c.v. injection of Al(mal)₃ significantly suppressed the field excitatory postsynaptic potential (fEPSP) amplitude, as indicated by a decrease in BDNF protein expression, which was accompanied by dose-dependent decreases in β-catenin protein expression and the phosphorylation of GSK-3β at Ser9. Rats that received SB216763, a GSK-3β inhibitor, exhibited higher fEPSP amplitudes than control rats. Furthermore, SB216763 treatment upregulated the hippocampal protein expression of BDNF and β-catenin while increasing the ratio of p-GSK-3β/GSK-3β. From the perspective of the identified β-catenin-BDNF axis, Al impairs hippocampal LTP, possibly through the GSK-3β/β-catenin signaling-mediated BDNF pathway.

Anti-fibrotic effect of 6-bromo-indirubin-3'-oxime (6-BIO) via regulation of activator protein-1 (AP-1) and specificity protein-1 (SP-1) transcription factors in kidney cells

PAI-1 and CTGF are overexpressed in kidney diseases and cause fibrosis of the lungs, liver, and kidneys. We used a rat model of unilateral ureteral obstruction (UUO) to investigate whether 6-BIO, a glycogen synthase kinase-3β inhibitor, attenuated fibrosis by inhibiting PAI-1 and CTGF in vivo. Additionally, TGFβ-induced cellular fibrosis was observed in vitro using the human kidney proximal tubular epithelial cells (HK-2), and rat interstitial fibroblasts (NRK49F). Expression of fibrosis-related proteins and signaling molecules such as PAI-1, CTGF, TGFβ, αSMA, SMAD, and MAPK were determined in HK-2 and NRK49F cells using immunoblotting. To identify the transcription factors that regulate the expression of PAI-1 and CTGF the promoter activities of AP-1 and SP-1 were analyzed using luciferase assays. Confocal microscopy was used to observe the co-localization of AP-1 and SP-1 to PAI-1 and CTGF. Expression of PAI-1, CTGF, TGFβ, and α-SMA increased in UUO model as well as in TGFβ-treated HK-2 and NRK49F cells. Furthermore, UUO and TGFβ treatment induced the activation of P-SMAD2/3, SMAD4, P-ERK 1/2, P-P38, and P-JNK MAPK signaling pathways. PAI-1, CTGF, AP-1 and SP-1 promoter activity increased in response to TGFβ treatment. However, treatment with 6-BIO decreased the expression of proteins and signaling pathways associated with fibrosis in UUO model as well as in TGFβ-treated HK-2 and NRK49F cells. Moreover, 6-BIO treatment attenuated the expression of PAI-1 and CTGF as well as the promoter activities of AP-1 and SP-1, thereby regulating the SMAD and MAPK signaling pathways, and subsequently exerting anti-fibrotic effects on kidney cells.

Glycogen synthesis and beyond, a comprehensive review of GSK3 as a key regulator of metabolic pathways and a therapeutic target for treating metabolic diseases

Glycogen synthase kinase‐3 (GSK3) is a highly evolutionarily conserved serine/threonine protein kinase first identified as an enzyme that regulates glycogen synthase (GS) in response to insulin stimulation, which involves GSK3 regulation of glucose metabolism and energy homeostasis. Both isoforms of GSK3, GSK3α, and GSK3β, have been implicated in many biological and pathophysiological processes. The various functions of GSK3 are indicated by its widespread distribution in multiple cell types and tissues. The studies of GSK3 activity using animal models and the observed effects of GSK3‐specific inhibitors provide more insights into the roles of GSK3 in regulating energy metabolism and homeostasis. The cross‐talk between GSK3 and some important energy regulators and sensors and the regulation of GSK3 in mitochondrial activity and component function further highlight the molecular mechanisms in which GSK3 is involved to regulate the metabolic activity, beyond its classical regulatory effect on GS. In this review, we summarize the specific roles of GSK3 in energy metabolism regulation in tissues that are tightly associated with energy metabolism and the functions of GSK3 in the development of metabolic disorders. We also address the impacts of GSK3 on the regulation of mitochondrial function, activity and associated metabolic regulation. The application of GSK3 inhibitors in clinical tests will be highlighted too. Interactions between GSK3 and important energy regulators and GSK3‐mediated responses to different stresses that are related to metabolism are described to provide a brief overview of previously less‐appreciated biological functions of GSK3 in energy metabolism and associated diseases through its regulation of GS and other functions.

Enhanced glycolysis and GSK3 inactivation promote brain metabolic adaptations following neuronal mitochondrial stress

We analyzed early brain metabolic adaptations in response to mitochondrial dysfunction in a mouse model of mitochondrial encephalopathy with complex IV deficiency (neuron specific COX10 KO). In this mouse model the onset of the mitochondrial defect did not coincide with immediate cell death suggesting early adaptive metabolic responses to compensate for the energetic deficit. Metabolomic analysis in the knockout mice revealed increased levels of glycolytic and pentose phosphate pathway intermediates, amino acids and lysolipids. Glycolysis was modulated by enhanced activity of glycolytic enzymes, and not by their overexpression, suggesting the importance of post-translational modifications in the adaptive response. GSK3 inactivation was the most upstream regulation identified, implying that it is a key event in this adaptive mechanism. Because neurons are thought not to rely on glycolysis for ATP production in normal conditions, our results indicate that neurons still maintain their ability to upregulate this pathway when under mitochondrial respiration stress.

Glycogen synthase kinase-3 (GSK-3) a magic enzyme: it's role in diabetes mellitus and glucose homeostasis, interactions with fluroquionlones. A mini-review

Diabetes mellitus (DM) is a non-communicable disease throughout the world in which there is persistently high blood glucose level from the normal range. The diabetes and insulin resistance are mainly responsible for the morbidities and mortalities of humans in the world. This disease is mainly regulated by various enzymes and hormones among which Glycogen synthase kinase-3 (GSK-3) is a principle enzyme and insulin is the key hormone regulating it. The GSK-3, that is the key enzyme is normally showing its actions by various mechanisms that include its phosphorylation, formation of protein complexes, and other cellular distribution and thus it control and directly affects cellular morphology, its growth, mobility and apoptosis of the cell. Disturbances in the action of GSK-3 enzyme may leads to various disease conditions that include insulin resistance leading to diabetes, neurological disease like Alzheimer's disease and cancer. Fluoroquinolones are the most common class of drugs that shows dysglycemic effects via interacting with GSK-3 enzyme. Therefore, it is the need of the day to properly understand functions and mechanisms of GSK-3, especially its role in glucose homeostasis via effects on glycogen synthase.

Photodynamic Therapy and Hyperthermia in Combination Treatment-Neglected Forces in the Fight against Cancer

Cancer is one of the leading causes of death in humans. Despite the progress in cancer treatment, and an increase in the effectiveness of diagnostic methods, cancer is still highly lethal and very difficult to treat in many cases. Combination therapy, in the context of cancer treatment, seems to be a promising option that may allow minimizing treatment side effects and may have a significant impact on the cure. It may also increase the effectiveness of anti-cancer therapies. Moreover, combination treatment can significantly increase delivery of drugs to cancerous tissues. Photodynamic therapy and hyperthermia seem to be ideal examples that prove the effectiveness of combination therapy. These two kinds of therapy can kill cancer cells through different mechanisms and activate various signaling pathways. Both PDT and hyperthermia play significant roles in the perfusion of a tumor and the network of blood vessels wrapped around it. The main goal of combination therapy is to combine separate mechanisms of action that will make cancer cells more sensitive to a given therapeutic agent. Such an approach in treatment may contribute toward increasing its effectiveness, optimizing the cancer treatment process in the future.

Marine-Derived Compounds with Anti-Alzheimer's Disease Activities

Alzheimer’s disease (AD) is an irreversible and progressive brain disorder that slowly destroys memory and thinking skills, and, eventually, the ability to perform simple tasks. As the aging population continues to increase exponentially, AD has become a big concern for society. Therefore, neuroprotective compounds are in the spotlight, as a means to tackle this problem. On the other hand, since it is believed—in many cultures—that marine organisms in an individual diet cannot only improve brain functioning, but also slow down its dysfunction, many researchers have focused on identifying neuroprotective compounds from marine resources. The fact that the marine environment is a rich source of structurally unique and biologically and pharmacologically active compounds, with unprecedented mechanisms of action, marine macroorganisms, such as tunicates, corals, sponges, algae, as well as microorganisms, such as marine-derived bacteria, actinomycetes, and fungi, have been the target sources of these compounds. Therefore, this literature review summarizes and categorizes various classes of marine-derived compounds that are able to inhibit key enzymes involved in AD, including acetylcholinesterase (AChE), butyrylcholinesterase (BuChE), β-secretase (BACE-1), and different kinases, together with the related pathways involved in the pathogenesis of AD. The compounds discussed herein are emerging as promising anti-AD activities for further in-depth in vitro and in vivo investigations, to gain more insight of their mechanisms of action and for the development of potential anti-AD drug leads.

The Tumor Microenvironment Factors That Promote Resistance to Immune Checkpoint Blockade Therapy

Through genetic and epigenetic alterations, cancer cells present the immune system with a diversity of antigens or neoantigens, which the organism must distinguish from self. The immune system responds to neoantigens by activating naïve T cells, which mount an anticancer cytotoxic response. T cell activation begins when the T cell receptor (TCR) interacts with the antigen, which is displayed by the major histocompatibility complex (MHC) on antigen-presenting cells (APCs). Subsequently, accessory stimulatory or inhibitory molecules transduce a secondary signal in concert with the TCR/antigen mediated stimulus. These molecules serve to modulate the activation signal's strength at the immune synapse. Therefore, the activation signal's optimum amplitude is maintained by a balance between the costimulatory and inhibitory signals. This system comprises the so-called immune checkpoints such as the programmed cell death (PD-1) and Cytotoxic T lymphocyte-associated antigen-4 (CTLA-4) and is crucial for the maintenance of self-tolerance. Cancers often evade the intrinsic anti-tumor activity present in normal physiology primarily by the downregulation of T cell activation. The blockade of the immune checkpoint inhibitors using specific monoclonal antibodies has emerged as a potentially powerful anticancer therapy strategy. Several drugs have been approved mainly for solid tumors. However, it has emerged that there are innate and acquired mechanisms by which resistance is developed against these therapies. Some of these are tumor-intrinsic mechanisms, while others are tumor-extrinsic whereby the microenvironment may have innate or acquired resistance to checkpoint inhibitors. This review article will examine mechanisms by which resistance is mounted against immune checkpoint inhibitors focussing on anti-CTL4-A and anti-PD-1/PD-Ll since drugs targeting these checkpoints are the most developed.

PROTACs technology for targeting non-oncoproteins: Advances and perspectives

Proteolysis targeting chimeras (PROTACs) have been developed to be an effective technology for targeted protein degradation. Each PROTAC contains three key components: a protein-of-interest (POI) ligand, an E3 ligase ligand, and a linker. These bifunctional molecules can hijack the intracellular inherent ubiquitin-proteasome system to degrade different POIs. With several advantages over other therapeutic strategies, PROTACs have set off a new upsurge of drug discovery in recent years. PRTOACs have been extensively explored worldwide and have excelled not only in cancer diseases but also in cardiovascular diseases, fatty liver disease, immune diseases, neurodegenerative diseases, and viral infections. In this review, we aim to summarize the rapid progress from 2010 to 2021 in PROTACs targeting various non-oncoproteins and elucidate the advantages of PROTACs technology. Finally, the potential challenges of this dynamic field are also discussed.

Dual Anti-Malarial and GSK3β-Mediated Cytokine-Modulating Activities of Quercetin Are Requisite of Its Potential as a Plant-Derived Therapeutic in Malaria

Although death in malaria is attributed to cerebrovascular blockage and anaemia, overwhelming cytokine production can contribute to the severity of the disease. Therefore, mitigation of dysregulated inflammatory signalling may provide further benefit for malaria treatment. Quercetin (3,3′,4′,5,7-pentahydroxyflavone) is known to inhibit glycogen synthase kinase-3β (GSK3β), a potent regulator of both pro- and anti-inflammatory effects. Quercetin is therefore a potential therapeutic to modulate the imbalanced cytokine production during malarial infection. Anti-malarial effects of quercetin were evaluated in murine models of severe and cerebral malaria using Plasmodium berghei NK65 and ANKA strains, respectively. Western blotting and analysis of cytokines were carried out to determine the GSK3β-mediated cytokine-modulating effects of quercetin in infected animals. Quercetin (25 mg/kg BW) treatment in P. berghei NK65-infected animals resulted in 60.7 ± 2.4% suppression of parasitaemia and significantly decreased serum levels of TNF-α and IFN-γ, whilst levels of IL-10 and IL-4 were elevated significantly. Western analysis revealed that pGSK3β (Ser9) increased 2.7-fold in the liver of quercetin-treated NK65-infected animals. Treatment of P. berghei ANKA-infected mice with quercetin (15 mg/kg BW) increased (2.3-fold) pGSK3β (Ser9) in the brains of infected animals. Quercetin is a potential plant-derived therapeutic for malaria on the basis that it can elicit anti-malarial and GSK3β-mediated cytokine-modulating effects.

The Aurora kinase/β-catenin axis contributes to dexamethasone resistance in leukemia

Glucocorticoids, such as dexamethasone and prednisolone, are widely used in cancer treatment. Different hematological malignancies respond differently to this treatment which, as could be expected, correlates with treatment outcome. In this study, we have used a glucocorticoid-induced gene signature to develop a deep learning model that can predict dexamethasone sensitivity. By combining gene expression data from cell lines and patients with acute lymphoblastic leukemia, we observed that the model is useful for the classification of patients. Predicted samples have been used to detect deregulated pathways that lead to dexamethasone resistance. Gene set enrichment analysis, peptide substrate-based kinase profiling assay, and western blot analysis identified Aurora kinase, S6K, p38, and β-catenin as key signaling proteins involved in dexamethasone resistance. Deep learning-enabled drug synergy prediction followed by in vitro drug synergy analysis identified kinase inhibitors against Aurora kinase, JAK, S6K, and mTOR that displayed synergy with dexamethasone. Combining pathway enrichment, kinase regulation, and kinase inhibition data, we propose that Aurora kinase or its several direct or indirect downstream kinase effectors such as mTOR, S6K, p38, and JAK may be involved in β-catenin stabilization through phosphorylation-dependent inactivation of GSK-3β. Collectively, our data suggest that activation of the Aurora kinase/β-catenin axis during dexamethasone treatment may contribute to cell survival signaling which is possibly maintained in patients who are resistant to dexamethasone.

Human gut microbiota Agathobaculum butyriciproducens improves cognitive impairment in LPS-induced and APP/PS1 mouse models of Alzheimer's disease

Alzheimer's disease (AD) is the most prevalent neurodegenerative disease, and is characterized by the accumulation and presence of amyloid plaques (Aβ), tangles, dementia, and cognitive impairment. Currently, there is no known cure for AD; however, recently, the association between alteration of the gut microbiota and AD pathology has been explored to find novel therapeutic approaches. Microbiota-targeted intervention has been suggested as an attractive therapeutic approach for AD. Agathobaculum butyriciproducens (SR79) is a strict anaerobic and butyric acid-producing bacteria. We hypothesized that administration of SR79 might have a beneficial effect on cognitive deficits and AD pathologies. To determine the therapeutic effects of SR79 on AD pathologies, APP/PS1 transgenic and lipopolysaccharide -induced cognitive impairment mouse models were used. In the lipopolysaccharide -induced cognitive deficit model, the administration of SR79 improved cognitive function and decreased microglia activation. In addition, the administration of SR79 to APP/PS1 mice significantly improved novel object recognition and percent alteration results in novel object recognition and Y-maze alteration tests. Furthermore, Aβ plaque deposition and microglial activation were markedly reduced in the parietal cortex and hippocampus after SR79 treatment in APP/PS1 mice. SR79 treatment significantly decreased gene expression levels of IL-1β and C1QB and increased the gene expression levels of IGF-1 and thereby the downstream signaling pathway in the cortex of APP/PS1 mice. In conclusion, SR79 administration improved cognitive function and AD pathologies through the regulation of neuroinflammation and IGF-1 signaling in an animal model.

PROTACs suppression of GSK-3β, a crucial kinase in neurodegenerative diseases

Glycogen synthase kinase 3β (GSK-3β) is involved in a variety of diseases such as neurodegenerative diseases, bipolar disorder, and diabetes. In this study, a series of heterobifunctional small molecule proteolysis targeting chimera (PROTAC) were designed and synthesized based on E3 ubiquitin ligase cereblon (CRBN). Most of PROTACs displayed good inhibitory activity, with the IC₅₀ values at the double-digits nanomolar levels and moderate protein degradation ability against GSK-3β. Western-blot data showed compound PG21 can effectively degrade GSK-3β in a dose-dependent manner, which can induce 44.2% protein degradation at 2.8 μM. Further pharmacological experiments revealed that the ability of PG21 to degrade GSK-3β is mediated by the ubiquitin-proteasome system (UPS). In addition, PG21 protects against glutamate-induced cell death in HT-22 cells. As the first PROTAC example to degrade GSK-3β protein, the present study has provided potential candidates for further investigation in the biological function of GSK-3β protein and its association with diseases.

Insight into glycogen synthase kinase-3β inhibitory activity of phyto-constituents from Melissa officinalis: in silico studies

Over activity of Glycogen synthase kinase-3β (GSK-3β), a serine/threonine-protein kinase has been implicated in a number of diseases including stroke, type II diabetes and Alzheimer disease (AD). This study aimed to find novel inhibitors of GSK-3β from phyto-constituents of Melissa officinalis with the aid of computational analysis. Molecular docking, induced-fit docking (IFD), calculation of binding free energy via the MM-GBSA approach and Lipinski's rule of five (RO5) were employed to filter the compounds and determine their druggability. Most importantly, the compounds pIC50 were predicted by machine learning-based model generated by AutoQSAR algorithm. The generated model was validated to affirm its predictive model. The best model obtained was Model kpls_desc_38 (R2 = 0.8467 and Q2 = 0.8069), and this external validated model was utilized to predict the bioactivities of the lead compounds. While a number of characterized compounds from Melissa officinalis showed better docking score, binding free energy alongside adherence to RO5 than co-cystallized ligand, only three compounds (salvianolic acid C, ellagic acid and naringenin) showed more satisfactory pIC50. The results obtained in this study can be useful to design potent inhibitors of GSK-3β.

A systematic review on anti-Alzheimer's disease activity of prescription Kangen-karyu

Traditional Chinese and Japanese medicines have become prime sources of drug discovery and there is a pressing need to investigate the effectiveness of these traditional medicines for modern drug discovery. Recently, among various traditional formulations, studies on Kangen-karyu (Guan-Yuan-Ke-Li), a mixture of six medicinal herbs (Salviae Miltiorrhizae Radix, Cnidii Rhizoma, Paeoniae Radix, Carthami Flos, Aucklandiae Radix, and Cyperi Rhizoma), have been growing to assess its neuroprotective role. This prompted us to undertake a thorough review of various targets of Kangen-karyu regarding its effectiveness against Alzheimer's disease, particularly focusing on cholinesterases, beta-site amyloid precursor protein cleaving enzyme 1, and glycogen synthase kinase 3β. This review provides new insights into Kangen-karyu medication as a prospective anti-Alzheimer's medication and indicates the need for in-depth in vivo investigation in the future.

Discovery of Novel Imidazopyridine GSK-3β Inhibitors Supported by Computational Approaches

The interest of research groups and pharmaceutical companies to discover novel GSK-3β inhibitors has increased over the years considering the involvement of this enzyme in many pathophysiological processes and diseases. Along this line, we recently reported on 1H-indazole-3-carboxamide (INDZ) derivatives 1-6, showing good GSK-3β inhibition activity. However, they suffered from generally poor central nervous system (CNS) permeability. Here, we describe the design, synthesis, and in vitro characterization of novel imidazo[1,5-a]pyridine-1-carboxamide (IMID 1) and imidazo[1,5-a]pyridine-3-carboxamide (IMID 2) compounds (7-18) to overcome such liability. In detail, structure-based approaches and fine-tuning of physicochemical properties guided the design of derivatives 7-18 resulting in ameliorated absorption, distribution, metabolism, and excretion (ADME) properties. A crystal structure of 16 in complex with GSK-3β enzyme (PDB entry 6Y9S) confirmed the in silico models. Despite the nanomolar inhibition activity, the new core compounds showed a reduction in potency with respect to INDZ derivatives 1-6. In this context, Molecular Dynamics (MD) and Quantum Mechanics (QM) based approaches along with NMR investigation helped to rationalize the observed structure activity relationship (SAR). With these findings, the key role of the acidic hydrogen of the central core for a tight interaction within the ATP pocket of the enzyme reflecting in good GSK-3β affinity was demonstrated.

Discovery and optimization of novel pyridines as highly potent and selective glycogen synthase kinase 3 inhibitors

Glycogen synthase kinase-3 plays an essential role in multiple biochemical pathways in the cell, particularly in regards to energy regulation. As such, Glycogen synthase kinase-3 is an attractive target for pharmacological intervention in a variety of disease states, particularly non-insulin dependent diabetes mellitus. However, due to homology with other crucial kinases, such as the cyclin-dependent protein kinase CDC2, developing compounds that are both potent and selective is challenging. A novel series of derivatives of 5-nitro-N2-(2-(pyridine-2ylamino)ethyl)pyridine-2,6-diamine were synthesized and have been shown to potently inhibit glycogen synthase kinase-3 (GSK3). Potency in the low nanomolar range was obtained along with remarkable selectivity. The compounds activate glycogen synthase in insulin receptor-expressing CHO-IR cells and in primary rat hepatocytes, and have acceptable pharmacokinetics and pharmacodynamics to allow for oral dosing. The X-ray co-crystal structure of human GSK3-β in complex with compound 2 is reported and provides insights into the structural determinants of the series responsible for its potency and selectivity.

Clinically relevant GSK‑3β inhibitor 9‑ING‑41 is active as a single agent and in combination with other antitumor therapies in human renal cancer

Glycogen synthase kinase-3 (GSK-3), a serine/threonine kinase, is involved in a broad range of pathological processes including cancer. GSK-3 has two isoforms, GSK-3α and GSK-3β, and GSK-3β has been recognized as a therapeutic target for the development of new anticancer drugs. The present study aimed to investigate the antitumor effects of 9-ING-41, which is a maleimide-based ATP-competitive small molecule GSK-3β inhibitor active in patients with advanced cancer. In renal cancer cell lines, treatment with 9-ING-41 alone induced cell cycle arrest and apoptosis, and autophagy inhibitors increased the antitumor effects of 9-ING-41 when used in combination. Treatment with 9-ING-41 potentiated the antitumor effects of targeted therapeutics and increased the cytotoxic effects of cytokine-activated immune cells on renal cancer cell lines. These results provided a compelling rationale for the inclusion of patients with renal cancer in studies of 9-ING-41, both as a single agent and in combination with current standard therapies.

How does the mood stabilizer lithium bind ATP, the energy currency of the cell: Insights from solid-state NMR

BACKGROUND

Lithium, in the form of a salt, is a mood stabilizer and a leading drug for the treatment of bipolar disorder. It has a very narrow therapeutic range and a variety of side effects. Lithium can replace magnesium and other cations in enzymes and small molecules, among them ATP, thereby affecting and inhibiting many biochemical pathways. The form of binding of lithium ions to ATP is not known.

METHODS

Here we extract the binding environment of lithium in solid ATP using a multi-nuclear multi-dimensional solid-state NMR approach.

RESULTS

We determine that the coordination sphere of lithium includes, at a distance of 3.0(±0.4) Å, three phosphates; the two phosphates closest to the ribose ring from one ATP molecule, and the middle phosphate from another ATP molecule. A water molecule most probably completes the fourth coordination. Despite the use of excess lithium in the preparations, sodium ions still remain bound to the sample, at distances of 4.3-5.5 Å from Li, and coordinate the first phosphate and two terminal phosphates.

CONCLUSIONS

Solid-state NMR enables to unravel the exact coordination of lithium in ATP showing binding to three phosphates from two molecules, none of which are the terminal gamma phosphate.

GENERAL SIGNIFICANCE

The methods we use are applicable to study lithium bound to a variety of ATP-bound enzymes, or to other cellular targets of lithium, consequently suggesting a molecular basis for its mode of action.

CXCL12 promotes atherosclerosis by downregulating ABCA1 expression via the CXCR4/GSK3β/β-cateninT120/TCF21 pathway

CXC chemokine ligand 12 (CXCL12) is a member of the CXC chemokine family and mainly acts on cell chemotaxis. CXCL12 also elicits a proatherogenic role, but the molecular mechanisms have not been fully defined yet. We aimed to reveal if and how CXCL12 promoted atherosclerosis via regulating lipid metabolism. In vitro, our data showed that CXCL12 could reduce ABCA1 expression, and it mediated cholesterol efflux from THP-1-derived macrophages to apoA-I. Data from the luciferase reporter gene and chromatin immunoprecipitation assays revealed that transcription factor 21 (TCF21) stimulated the transcription of ABCA1 via binding to its promoter region, which was repressed by CXCL12. We found that CXCL12 increased the levels of phosphorylated glycogen synthase kinase 3β (GSK3β) and the phosphorylation of β-catenin at the Thr120 position. Inactivation of GSK3β or β-catenin increased the expression of TCF21 and ABCA1. Further, knockdown or inhibition of CXC chemokine receptor 4 (CXCR4) blocked the effects of CXCL12 on TCF21 and ABCA1 expression and the phosphorylation of GSK3β and β-catenin. In vivo, the overexpression of CXCL12 in Apoe^-/- mice via lentivirus enlarged the atherosclerotic lesion area and increased macrophage infiltration in atherosclerotic plaques. We further found that the overexpression of CXCL12 reduced the efficiency of reverse cholesterol transport and plasma HDL-C levels, decreased ABCA1 expression in the aorta and mouse peritoneal macrophages (MPMs), and suppressed cholesterol efflux from MPMs to apoA-I in Apoe^-/- mice. Collectively, these findings suggest that CXCL12 interacts with CXCR4 and then activates the GSK-3β/β-catenin^T120/TCF21 signaling pathway to inhibit ABCA1-dependent cholesterol efflux from macrophages and aggravate atherosclerosis. Targeting CXCL12 may be a novel and promising strategy for the prevention and treatment of atherosclerotic cardiovascular diseases.

A Nutrigenomics Approach Using RNA Sequencing Technology to Study Nutrient-Gene Interactions in Agricultural Animals

Thorough understanding of animal gene expression driven by dietary nutrients can be regarded as a bottom line of advanced animal nutrition research. Nutrigenomics (including transcriptomics) studies the effects of dietary nutrients on cellular gene expression and, ultimately, phenotypic changes in living organisms. Transcriptomics can be applied to investigate animal tissue transcriptomes at a defined nutritional state, which can provide a holistic view of intracellular RNA expression. As a novel transcriptomics approach, RNA sequencing (RNA-Seq) technology can monitor all gene expressions simultaneously in response to dietary intervention. The principle and history of RNA-Seq are briefly reviewed, and its 3 principal steps are described in this article. Application of RNA-Seq in different areas of animal nutrition research is summarized. Lastly, the application of RNA-Seq in swine science and nutrition is also reviewed. In short, RNA-Seq holds significant potential to be employed for better understanding the nutrient-gene interactions in agricultural animals.

Hypothesis and Theory: Circulating Alzheimer's-Related Biomarkers in Type 2 Diabetes. Insight From the Goto-Kakizaki Rat

Epidemiological data suggest an increased risk of developing Alzheimer's disease (AD) in individuals with type 2 diabetes (T2D). AD is anatomically associated with an early progressive accumulation of Aβ leading to a gradual Tau hyperphosphorylation, which constitute the main characteristics of damaged brain in AD. Apart from these processes, mounting evidence suggests that specific features of diabetes, namely impaired glucose metabolism and insulin signaling in the brain, play a key role in AD. Moreover, several studies report a potential role of Aβ and Tau in peripheral tissues such as pancreatic β cells. Thus, it appears that several biological pathways associated with diabetes overlap with AD. The link between peripheral insulin resistance and brain insulin resistance with concomitant cognitive impairment may also potentially be mediated by a liver/pancreatic/brain axis, through the excessive trafficking of neurotoxic molecules across the blood-brain barrier. Insulin resistance incites inflammation and pro-inflammatory cytokine activation modulates the homocysteine cycle in T2D patients. Elevated plasma homocysteine level is a risk factor for AD pathology and is also closely associated with metabolic syndrome. We previously demonstrated a strong association between homocysteine metabolism and insulin via cystathionine beta synthase (CBS) activity, the enzyme implicated in the first step of the trans-sulfuration pathway, in Goto-Kakizaki (GK) rats, a spontaneous model of T2D, with close similarities with human T2D. CBS activity is also correlated with DYRK1A, a serine/threonine kinase regulating brain-derived neurotrophic factor (BDNF) levels, and Tau phosphorylation, which are implicated in a wide range of disease such as T2D and AD. We hypothesized that DYRK1A, BDNF, and Tau, could be among molecular factors linking T2D to AD. In this focused review, we briefly examine the main mechanisms linking AD to T2D and provide the first evidence that certain circulating AD biomarkers are found in diabetic GK rats. We propose that the spontaneous model of T2D in GK rat could be a suitable model to investigate molecular mechanisms linking T2D to AD.

Novel meriolin derivatives as rapid apoptosis inducers

3-(Hetero)aryl substituted 7-azaindoles possessing multikinase inhibitor activity are readily accessed in a one-pot Masuda borylation-Suzuki coupling sequence. Several promising derivatives were identified as apoptosis inducers and, emphasizing the multikinase inhibition potential, as sphingosine kinase 2 inhibitors. Our measurements provide additional insights into the structure-activity relationship of meriolin derivatives, suggesting derivatives bearing a pyridine moiety with amino groups in 2-position as most active anticancer compounds and thus as highly promising candidates for future in vivo studies.