Glycogen synthase kinase-3beta phosphorylates Bax and promotes its mitochondrial localization during neuronal apoptosis

Nanomedicine: A great boon for cardiac regenerative medicine

Cardiovascular disease (CVD) represents a significant global health challenge, remaining the leading cause of illness and mortality worldwide. The adult heart's limited regenerative capacity poses a major obstacle in repairing extensive damage caused by conditions like myocardial infarction. In response to these challenges, nanomedicine has emerged as a promising field aimed at improving treatment outcomes through innovative drug delivery strategies. Nanocarriers, such as nanoparticles (NPs), offer a revolutionary approach by facilitating targeted delivery of therapeutic agents directly to the heart. This precise delivery system holds immense potential for treating various cardiac conditions by addressing underlying mechanisms such as inflammation, oxidative stress, cell death, extracellular matrix remodeling, prosurvival signaling, and angiogenic pathways associated with ischemia-reperfusion injury. In this review, we provide a concise summary of the fundamental mechanisms involved in cardiac remodeling and regeneration. We explore how nanoparticle-based drug delivery systems can effectively target the afore-mentioned mechanisms. Furthermore, we discuss clinical trials that have utilized nanoparticle-based drug delivery systems specifically designed for cardiac applications. These trials demonstrate the potential of nanomedicine in clinical settings, paving the way for future advancements in cardiac therapeutics through precise and efficient drug delivery. Overall, nanomedicine holds promise in revolutionizing the treatment landscape of cardiovascular diseases by offering targeted and effective therapeutic strategies that address the complex pathophysiology of cardiac injuries.

Coenzyme Q10 ameliorates cyclophosphamide-induced chemobrain by repressing neuronal apoptosis and preserving hippocampal neurogenesis: Mechanistic roles of Wnt/ β-catenin signaling pathway

Deterioration in the neurocognitive function of cancer patients referred to as "Chemobrain" is a devastating obstacle associated with cyclophosphamide (CYP). CYP is an alkylating agent, clinically utilized as an efficient anticancer and immunosuppressant. Coenzyme Q10 (CoQ10) is a worthwhile micronutrient with diverse biological activities embracing antioxidant, anti-apoptotic, and neuroprotective effects. The current experiment was designed for investigating the neuroprotective capability of CoQ10 versus CYP-elicited chemobrain in rats besides elucidating the causal molecular mechanisms. Male Sprague Dawley rats received CoQ10 (10 mg/kg, orally, once daily, for 10 days) and/or a single dose of CYP (200 mg/kg i.p. on day 7). CoQ10 counteracted CYP-induced cognitive and motor dysfunction as demonstrated by the findings of neurobehavioral tests (passive avoidance, Y maze, locomotion, and rotarod tests). Histopathological analysis further affirmed the neuroprotective abilities of CoQ10. CoQ10 effectually diminished CYP-provoked oxidative injury by restoring the antioxidant activity of catalase (CAT) enzyme while reducing malondialdehyde (MDA) levels. Besides, CoQ10 efficiently repressed CYP-induced neuronal apoptosis by downregulating the expression of Bax and caspase-3 while upregulating the Bcl-2 expression. Moreover, CoQ10 hampered CYP-provoked upregulation in acetylcholinesterase (AChE) activity. Furthermore, CoQ10 considerably augmented hippocampal neurogenesis by elevating the expressions of brain-derived neurotrophic factor (BDNF) and Ki-67. These promising neuroprotective effects can be credited to upregulating Wnt/β-catenin pathway as evidenced by the elevated expressions of Wnt-3a, β-catenin, and Phoshpo-glycogen synthase kinase-3 β (p-GSK-3β). Collectively, these findings proved the neuroprotective capabilities of CoQ10 against CYP-induced chemobrain through combating oxidative injury, repressing intrinsic apoptosis, boosting neurogenesis, and eventually upregulating the Wnt/β-catenin pathway.

Novel Insights into Psychosis and Antipsychotic Interventions: From Managing Symptoms to Improving Outcomes

For the past 70 years, the dopamine hypothesis has been the key working model in schizophrenia. This has contributed to the development of numerous inhibitors of dopaminergic signaling and antipsychotic drugs, which led to rapid symptom resolution but only marginal outcome improvement. Over the past decades, there has been limited research on the quantifiable pathological changes in schizophrenia, including premature cellular/neuronal senescence, brain volume loss, the attenuation of gamma oscillations in electroencephalograms, and the oxidation of lipids in the plasma and mitochondrial membranes. We surmise that the aberrant activation of the aryl hydrocarbon receptor by toxins derived from gut microbes or the environment drives premature cellular and neuronal senescence, a hallmark of schizophrenia. Early brain aging promotes secondary changes, including the impairment and loss of mitochondria, gray matter depletion, decreased gamma oscillations, and a compensatory metabolic shift to lactate and lactylation. The aim of this narrative review is twofold: (1) to summarize what is known about premature cellular/neuronal senescence in schizophrenia or schizophrenia-like disorders, and (2) to discuss novel strategies for improving long-term outcomes in severe mental illness with natural senotherapeutics, membrane lipid replacement, mitochondrial transplantation, microbial phenazines, novel antioxidant phenothiazines, inhibitors of glycogen synthase kinase-3 beta, and aryl hydrocarbon receptor antagonists.

PI3K/AKT signaling activation by roflumilast ameliorates rotenone-induced Parkinson's disease in rats

Parkinson's disease (PD) is the second most common progressive age-related neurodegenerative disorder. Paramount evidence shed light on the role of PI3K/AKT signaling activation in the treatment of neurodegenerative disorders. PI3K/AKT signaling can be activated via cAMP-dependent pathways achieved by phosphodiesterase 4 (PDE4) inhibition. Roflumilast is a well-known PDE4 inhibitor that is currently used in the treatment of chronic obstructive pulmonary disease. Furthermore, roflumilast has been proposed as a favorable candidate for the treatment of neurological disorders. The current study aimed to unravel the neuroprotective role of roflumilast in the rotenone model of PD in rats. Ninety male rats were allocated into six groups as follows: control, rotenone (1.5 mg/kg/48 h, s.c.), L-dopa (22.5 mg/kg, p.o), and roflumilast (0.2, 0.4 or 0.8 mg/kg, p.o). All treatments were administrated for 21 days 1 h after rotenone injection. Rats treated with roflumilast showed an improvement in motor activity and coordination as well as preservation of dopaminergic neurons in the striatum. Moreover, roflumilast increased cAMP level and activated the PI3K/AKT axis via stimulation of CREB/BDNF/TrkB and SIRT1/PTP1B/IGF1 signaling cascades. Roflumilast also caused an upsurge in mTOR and Nrf2, halted GSK-3β and NF-ĸB, and suppressed FoxO1 and caspase-3. Our study revealed that roflumilast exerted neuroprotective effects in rotenone-induced neurotoxicity in rats. These neuroprotective effects were mediated via the crosstalk between CREB/BDNF/TrkB and SIRT1/PTP1B/IGF1 signaling pathways which activates PI3K/AKT trajectory. Therefore, PDE4 inhibition is likely to offer a reliable persuasive avenue in curing PD via PI3K/AKT signaling activation.

Empagliflozin and pirfenidone confer renoprotection through suppression of glycogen synthase kinase-3β and promotion of tubular regeneration in rats with induced metabolic syndrome

Metabolic syndrome (MetS) is largely coupled with chronic kidney disease (CKD). Glycogen synthase kinase-3β (GSK-3β) pathway drives tubular injury in animal models of acute kidney injury; but its contribution in CKD is still elusive. This study investigated the effect empagliflozin and/or pirfenidone against MetS-induced kidney dysfunction, and to clarify additional underpinning mechanisms particularly the GSK-3β signaling pathway. Adult male rats received 10%w/v fructose in drinking water for 20 weeks to develop MetS, then treated with either drug vehicle, empagliflozin (30 mg/kg/day) and/or pirfenidone (100 mg/kg/day) via oral gavage for subsequent 4 weeks, concurrently with the high dietary fructose. Age-matched rats receiving normal drinking water were used as controls. After 24 weeks, blood and kidneys were harvested for subsequent analyses. Rats with MetS showed signs of kidney dysfunction, structural changes and interstitial fibrosis. Activation of GSK-3β, decreased cyclinD1 expression and enhanced apoptotic signaling were found in kidneys of MetS rats. There was abundant alpha-smooth muscle actin (α-SMA) expression along with up-regulation of TGF-β1/Smad3 in kidneys of MetS rats. These derangements were almost alleviated by empagliflozin or pirfenidone, with evidence that the combined therapy was more effective than either individual drug. This study emphasizes a novel mechanism underpinning the beneficial effects of empagliflozin and pirfenidone on kidney dysfunction associated with MetS through targeting GSK-3β signaling which can mediate the regenerative capacity, anti-apoptotic effects and anti-fibrotic properties of such drugs. These findings recommend the possibility of using empagliflozin and pirfenidone as promising therapies for management of CKD in patients with MetS.

WSB1, as an E3 ligase, restrains myocardial ischemia-reperfusion injury by activating β-catenin signaling via promoting GSK3β ubiquitination

BACKGROUND

Reperfusion is the most effective strategy for myocardial infarct, but induces additional injury. WD repeat and SOCS box containing protein 1 (WSB1) plays a protective role in ischemic cells. This study aims to investigate the effects of WSB1 on myocardial ischemia-reperfusion (IR) injury.

METHODS

The myocardial IR was induced by left anterior descending (LAD) ligation for 45 min and subsequent reperfusion. The overexpression of WSB1 was mediated by tail vein injection of AAV9 loaded with WSB1 encoding sequence two weeks before IR surgery. H9c2 myocardial cells underwent oxygen-sugar deprivation/reperfusion (OGD/R) to mimic IR, and transfected with WSB1 overexpression or silencing plasmid to alter the expression of WSB1.

RESULTS

WSB1 was found highly expressed in penumbra of myocardial IR rats, and the WSB1 overexpression relieved IR-induced cardio dysfunction, myocardial infarct and pathological damage, and cardiomyocyte death in penumbra. The ectopic expression of WSB1 in H9c2 myocardial cells mitigated OGD/R-caused apoptosis, and silencing of WSB1 exacerbated the apoptosis. In addition, WSB1 activated β-catenin signaling, which was deactivated under the ischemic condition. The co-immunoprecipitation results revealed that WSB1 mediated ubiquitination and degradation of glycogen synthase kinase 3 beta (GSK3β) as an E3 ligase in myocardial cells. The effects of WSB1 on myocardial cells under ischemic conditions were abolished by an inhibitor of β-catenin signaling.

CONCLUSION

WSB1 activated β-catenin pathway by promoting the ubiquitination of GSK3β, and restrained IR-induced myocardial injury. These findings might provide novel insights for clinical treatment of myocardial ischemic patients.

Kinase signalling adaptation supports dysfunctional mitochondria in disease

Mitochondria form a critical control nexus which are essential for maintaining correct tissue homeostasis. An increasing number of studies have identified dysregulation of mitochondria as a driver in cancer. However, which pathways support and promote this adapted mitochondrial function? A key hallmark of cancer is perturbation of kinase signalling pathways. These pathways include mitogen activated protein kinases (MAPK), lipid secondary messenger networks, cyclic-AMP-activated (cAMP)/AMP-activated kinases (AMPK), and Ca2+/calmodulin-dependent protein kinase (CaMK) networks. These signalling pathways have multiple substrates which support initiation and persistence of cancer. Many of these are involved in the regulation of mitochondrial morphology, mitochondrial apoptosis, mitochondrial calcium homeostasis, mitochondrial associated membranes (MAMs), and retrograde ROS signalling. This review will aim to both explore how kinase signalling integrates with these critical mitochondrial pathways and highlight how these systems can be usurped to support the development of disease. In addition, we will identify areas which require further investigation to fully understand the complexities of these regulatory interactions. Overall, this review will emphasize how studying the interaction between kinase signalling and mitochondria improves our understanding of mitochondrial homeostasis and can yield novel therapeutic targets to treat disease.

Mitochondrial Signaling, the Mechanisms of AKI-to-CKD Transition and Potential Treatment Targets

Acute kidney injury (AKI) is increasing in prevalence and causes a global health burden. AKI is associated with significant mortality and can subsequently develop into chronic kidney disease (CKD). The kidney is one of the most energy-demanding organs in the human body and has a role in active solute transport, maintenance of electrochemical gradients, and regulation of fluid balance. Renal proximal tubular cells (PTCs) are the primary segment to reabsorb and secrete various solutes and take part in AKI initiation. Mitochondria, which are enriched in PTCs, are the main source of adenosine triphosphate (ATP) in cells as generated through oxidative phosphorylation. Mitochondrial dysfunction may result in reactive oxygen species (ROS) production, impaired biogenesis, oxidative stress multiplication, and ultimately leading to cell death. Even though mitochondrial damage and malfunction have been observed in both human kidney disease and animal models of AKI and CKD, the mechanism of mitochondrial signaling in PTC for AKI-to-CKD transition remains unknown. We review the recent findings of the development of AKI-to-CKD transition with a focus on mitochondrial disorders in PTCs. We propose that mitochondrial signaling is a key mechanism of the progression of AKI to CKD and potential targeting for treatment.

Asperosaponin VI facilitates the regeneration of skeletal muscle injury by suppressing GSK-3β-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-3β (GSK-3β) 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-3β 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-3β signaling and promotes regeneration, thus presenting a probable therapeutic agent for skeletal muscle injury.

Inhibitory actions of oxyresveratrol on the PI3K/AKT signaling cascade in cervical cancer cells

The phosphatidyl inositol 3-kinase (PI3K)/AKT signaling plays a critical role in cancer cell proliferation, migration, and invasion. This signal transduction axis in HPV-positive cervical cancer has been proved to be directly activated by E6/E7 proteins of the virus enhancing cervical cancer progression. Hence, the PI3K/AKT pathway is one of the key therapeutic targets for HPV-positive cervical cancer. Here we discovered that oxyresveratrol (Oxy) at noncytotoxic concentration specifically suppressed the phosphorylation of AKT but not ERK1/2. This potent inhibitory effect of Oxy was still observed even when cells were stimulated with fetal bovine serum. Inhibition of AKT phosphorylation at serine 473 by Oxy resulted in a significant decrease in serine 9 phosphorylation of GSK-3β, a downstream target of AKT. Dephosphorylation of GSK-3β at this serine residue activates its function in promoting the degradation of MCL-1, an anti-apoptotic protein. Results clearly demonstrated that in association with GSK-3β activation, Oxy preferentially downregulated the expression of anti-apoptotic protein MCL-1. Furthermore, results from the functional analyses revealed that Oxy inhibited cervical cancer cell proliferation, at least in part through suppressing nuclear expression of Ki-67. Besides, the compound retarded cervical cancer cell migration even the cells were exposed to a potent enhancer of epithelial-mesenchymal transition, TGF-β1. In consistent with these data, Oxy reduced the expression of β-catenin, N-cadherin, and vimentin. In conclusion, the study disclosed that Oxy specifically inhibits the AKT/GSK-3β/MCL-1 axis resulting in reduction in cervical cancer cell viability, proliferation, and migration.

New insights into glycogen synthase kinase-3: A common target for neurodegenerative diseases

Glycogen synthase kinase 3 (GSK-3) is a highly conserved protein serine/threonine kinase that plays a central role in a wide variety of cellular processes to coordinate catabolic and anabolic pathways and regulate cell growth and fate. There is increasing evidence showing that abnormal glycogen synthase kinase 3 (GSK-3) is associated with the pathogenesis and progression of many disorders, such as cancer, diabetes, psychiatric diseases, and neurodegenerative diseases. In this review, we summarize recent findings about the regulatory role of GSK-3 in the occurrence and development of multiple neurodegenerative diseases, mainly focusing on Alzheimer's disease, Parkinson's disease, and amyotrophic lateral sclerosis. The aim of this study is to provide new insight into the shared working mechanism of GSK-3 as a therapeutic target of multiple neurodegenerative diseases.

Involvement of histone methylation in the regulation of neuronal death

Neuronal death occurs in various physiological and pathological processes, and apoptosis, necrosis, and ferroptosis are three major forms of neuronal death. Neuronal apoptosis, necrosis, and ferroptosis are widely identified to involve the progress of stroke, Parkinson's disease, and Alzheimer's disease. A growing body of evidence has pointed out that neuronal death is tightly associated with expression of related genes and alteration of signaling molecules. In addition, recently, epigenetics has been increasingly focused on as a vital regulatory mechanism for neuronal apoptosis, necrosis, and ferroptosis, providing a new direction for treating nervous system diseases. Moreover, growing researches suggest that histone methylation or demethylation is involved in the processes of neuronal apoptosis, necrosis, and ferroptosis. These researches may imply that studying the potential roles of histone methylation is essential for treating the nervous system diseases. Here, we review potential roles of histone methylation and demethylation in neuronal death, which may give us a new direction in treating the nervous system diseases.

Neurovascular protection of alisol A on cerebral ischemia mice through activating the AKT/GSK3β pathway

Alisol A, a triterpene isolated from Alisma Orientale, has been shown to exhibit anti-inflammatory effects and vascular protection. This study was designed to observe the effect of alisol A on cerebral ischemia (CI)-induced neurovascular dysfunction in the hippocampus and to further explore the potential mechanisms. The results showed that alisol A treatment improved the neurological deficits and cognitive impairment of CI mice. Alisol A reduced gliosis and improved neuronal/glial metabolism. Accordingly, alisol A inhibited inflammatory factors IL-6 and IL-1β induced by overactivation of astrocytes and microglia, thus protecting the neurovasculature. Furthermore, alisol A promoted the survival of neurons by decreasing the ratio of Bax/Bcl-2, and protected brain microvascular endothelial cells (BMECs) by upregulating the expression of ZO-1, Occludin and CD31. The phosphorylation of protein kinase B (AKT) and glycogen synthase kinase 3β (GSK3β) increased after treatment with alisol A. To explore the underlying mechanism, AKT was inhibited. As expected, the neurovascular protection of alisol A above was eliminated by AKT inhibition. The present study primarily suggested that alisol A could exert neurovascular protection in the hippocampus of CI mice by activating the AKT/GSK3β pathway and may potentially be used for the treatment of CI.

LAR Downregulation Protects the Astrocytic U251 and Cocultured SH-SY5Y Cells in a Rotenone-Induced Parkinson's Disease Cell Model

Leukocyte common antigen-related protein tyrosine phosphatase (LAR) is a member of the protein tyrosine phosphatase family that serves as a key regulator of cellular survival. It is also involved in neurodevelopment and brain disorders. This study was designed to investigate the role of LAR in a cell-based model of Parkinson's disease (PD) in which U251 and SH-SY5Y cells were used as models of astrocytes and dopaminergic neurons, respectively. Cell viability, cell death, cell morphology, protein phosphorylation and expression, ATP levels, reactive oxygen species (ROS) generation, and mitochondrial membrane potential were analyzed in the wild-type (WT) and heterozygous LAR-knockout astrocytoma U251 cells to assess the cell state, signal transduction, and mitochondrial function. LAR downregulation showed a protective effect in rotenone-exposed U251 cells by increasing cell viability, reducing cell mortality, and restoring appropriate cellular morphology. LAR downregulation enhanced IGF-1R phosphorylation and downstream signal transduction as evidenced by increases in the Akt and GSK-3β phosphorylation, as well as the upregulation of NRF2 and HO-1. The downregulation of LAR also augmented DJ-1 levels in these cells. The enhanced Akt and GSK-3β phosphorylation contributed to a reduced Bax/Bcl2 ratio and suppressed apoptosis after rotenone exposure. Heterozygous LAR-knockout U251 cells exhibited higher mitochondrial function evidenced by increased mitochondrial membrane potential, ATP contents, and reduced ROS production compared to the WT cells following rotenone exposure. Further studies showed that the astrocytic protection mediated by the heterozygous knockout of LAR was associated with the activation of Akt. A specific Akt inhibitor, MK2206, reduced the cell viability, Akt and GSK3β phosphorylation, and HO-1 and NRF2 expression in U251 cells exposed to rotenone. Astrocytes provide structural and metabolic support to maintain neuronal health. Astrocytic glial cell-derived neurotrophic factor (GDNF) production is vital for dopaminergic neuron survival. Heterozygous LAR-knockout U251 cells produced higher amounts of GDNF than the WT cells. The SH-SY5Y cells cocultured with heterozygous LAR-knockout U251 cells exhibited greater viability than that of cells cocultured with WT U251 cells in response to rotenone. Together, these findings demonstrate that the heterozygous knockout of LAR in astrocytes can play a key role in protecting both astrocytic cells and cocultured neurons in a rotenone-induced cell-based model of PD. This neuroprotective effect is attributable to the augmentation of IGF1R-Akt-GDNF signaling and the maintenance of astrocytic mitochondrial function.

Mitochondria dysfunction and bipolar disorder: From pathology to therapy

Bipolar disorder (BD) is one of the major psychiatric diseases in which the impairment of mitochondrial functions has been closely connected or associated with the disease pathologies. Different lines of evidence of the close connection between mitochondria dysfunction and BD were discussed with a particular focus on (1) dysregulation of energy metabolism, (2) effect of genetic variants, (3) oxidative stress, cell death and apoptosis, (4) dysregulated calcium homeostasis and electrophysiology, and (5) current as well as potential treatments targeting at restoring mitochondrial functions. Currently, pharmacological interventions generally provide limited efficacy in preventing relapses or recovery from mania or depression episodes. Thus, understanding mitochondrial pathology in BD will lead to novel agents targeting mitochondrial dysfunction and formulating new effective therapy for BD.

The GSK3β/Mcl-1 axis is regulated by both FLT3-ITD and Axl and determines the apoptosis induction abilities of FLT3-ITD inhibitors

Acute myeloid leukemia (AML) patients with FLT3-ITD mutations are associated with poor prognosis. FLT3-ITD inhibitors are developed and result in transient disease remission, but generally resistance develops. We propose that resistance occurs due to apoptosis evasion. We compared the abilities of five clinically used FLT3-ITD inhibitors, namely, midostaurin, crenolanib, gilteritinib, quizartinib, and sorafenib, to induce apoptosis. These drugs inhibit FLT3-ITD and induce apoptosis. Apoptosis induction is associated with GSK3β activation, Mcl-1 downregulation, and Bim upregulation. Sorafenib-resistant MOLM-13/sor cells have the secondary D835Y mutation and increased Axl signaling pathway with cross-resistance to quizartinib. Gilteritinib and crenolanib inhibit both FLT3-ITD and Axl and induce apoptosis in MOLM-13/sor cells, in which they activate GSK3β and downregulate Mcl-1. Inactivation of GSK3β through phosphorylation and inhibitors blocks apoptosis and Mcl-1 reduction. The Axl/GSK3β/Mcl-1 axis works as a feedback mechanism to attenuate apoptosis of FLT3-ITD inhibition. Homoharringtonine decreases the protein levels of Mcl-1, FLT3-ITD, and Axl. Moreover, it synergistically induces apoptosis with gilteritinib in vitro and prolongs survival of MOLM-13/sor xenografts. The GSK3β/Mcl-1 axis works as the hub of FLT3-ITD inhibitors and plays a critical role in resistance against FLT3-ITD AML-targeted therapy.

GSK3 Is a Central Player in Retinal Degenerative Diseases but a Challenging Therapeutic Target

Glycogen synthase kinase 3 (GSK3) is a key regulator of many cellular signaling processes and performs a wide range of biological functions in the nervous system. Due to its central role in numerous cellular processes involved in cell degeneration, a rising number of studies have highlighted the interest in developing therapeutics targeting GSK3 to treat neurodegenerative diseases. Although recent works strongly suggest that inhibiting GSK3 might also be a promising therapeutic approach for retinal degenerative diseases, its full potential is still under-evaluated. In this review, we summarize the literature on the role of GSK3 on the main cellular functions reported as deregulated during retinal degeneration, such as glucose homeostasis which is critical for photoreceptor survival, or oxidative stress, a major component of retinal degeneration. We also discuss the interest in targeting GSK3 for its beneficial effects on inflammation, for reducing neovascularization that occurs in some retinal dystrophies, or for cell-based therapy by enhancing Müller glia cell proliferation in diseased retina. Together, although GSK3 inhibitors hold promise as therapeutic agents, we highlight the complexity of targeting such a multitasked kinase and the need to increase our knowledge of the impact of reducing GSK3 activity on these multiple cellular pathways and biological processes.

Decrypting a path based approach for identifying the interplay between PI3K and GSK3 signaling cascade from the perspective of cancer

Cancer is one of those leading diseases worldwide, which takes millions of lives every year. Researchers are continuously looking for specific approaches to eradicate the deadly disease, ensuring minimal adverse effects along with more therapeutic significance. Targeting of different aberrantly regulated signaling pathways, involved in cancer, is surely one of the revolutionary chemotherapeutic approach. In this instance, GSK3 and PI3K signaling cascades are considered as important role player for both the oncogenic activation and inactivation which further leads to cancer proliferation and metastasis. In this review, we have discussed the potential role of GSK3 and PI3K signaling in cancer, and we further established the crosstalk between PI3K and GSK3 signaling, through showcasing their cross activation, cross inhibition and convergence pathways in association with cancer. We also exhibited the effect of GSK3 on the efficacy of PI3K inhibitors to overcome the drug resistance and preventing the cell proliferation, metastasis in a combinatorial way with GSK3 inhibitors for a better treatment strategy in clinical settings.

Effect of Cerium Oxide Nanoparticles on the Expression of Developmental and Apoptosis Genes of Testicular Tissue in 6-Day-Old NMRI Mice Fetuses

Cerium oxide (CeO₂) has potential applications in medicine and various consumer products. This study investigated the effect of CeO₂ on the expression of genes associated with apoptosis and testicular development in mouse embryos. The experimental groups of pregnant mice were injected intraperitoneally with CeO₂ at a concentration of 10 mg/kg on days 7 and 14 of pregnancy. Six days after birth, the testicles of neonatal male mice were collected for mRNA expression determination using real-time PCR, protein expression analysis by immunohistochemistry, and apoptotic cell population determination using the TUNEL assay. The results showed that the mRNA expression of the Bax, Caspase-3, and Gsk3-β genes, unlike the Bcl2 gene, decreased significantly in the experimental group compared to the control group. The expression ratio of Bax/Bcl2 in the experimental group was lower than in the control group. A similar trend was observed in the population of apoptotic cells. In the experimental group, the expression levels of, Gata4, Sox8, and Rad54 at both the mRNA and protein levels increased significantly compared to the control group. Based on the results of this study, CeO₂ at a concentration of 10 mg/kg, in addition to producing anti-apoptotic effects on the testicular cells of neonatal mice, can increase the expression of genes involved in testicular development and performance. The current experimental study proved the protective effects of 10 mg/kg CeO₂ in developmental and apoptosis genes of testicular tissue in 6-day-old NMRI mice fetuses; however, more experiments are required to evaluate the possible side effects and interactions.

Identification of metabolic pathways underlying FGF1 and CHIR99021-mediated cardioprotection

Acute myocardial infarction is a leading cause of death worldwide. We have previously identified two cardioprotective molecules — FGF1 and CHIR99021— that confer cardioprotection in mouse and pig models of acute myocardial infarction. Here, we aimed to determine if improved myocardial metabolism contributes to this cardioprotection. Nanofibers loaded with FGF1 and CHIR99021 were intramyocardially injected to ischemic myocardium of adult mice immediately following surgically induced myocardial infarction. Animals were euthanized 3 and 7 days later. Our data suggested that FGF1/CHIR99021 nanofibers enhanced the heart’s capacity to utilize glycolysis as an energy source and reduced the accumulation of branched-chain amino acids in ischemic myocardium. The impact of FGF1/CHIR99021 on metabolism was more obvious in the first three days post myocardial infarction. Taken together, these findings suggest that FGF1/CHIR99021 protects the heart against ischemic injury via improving myocardial metabolism which may be exploited for treatment of acute myocardial infarction in humans.

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FGF1/CHIR confer cardioprotection in myocardial infarction animals

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FGF1/CHIR enhance the capability of ischemic hearts to produce energy via glycolysis

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FGF1/CHIR reduce the abundance of branched chain amino acids in ischemic hearts

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This study reveals a novel approach to correct metabolic disorders in ischemic hearts

Pathobiology and Therapeutic Relevance of GSK-3 in Chronic Hematological Malignancies

Glycogen synthase kinase-3 (GSK-3) is an evolutionarily conserved, ubiquitously expressed, multifunctional serine/threonine protein kinase involved in the regulation of a variety of physiological processes. GSK-3 comprises two isoforms (α and β) which were originally discovered in 1980 as enzymes involved in glucose metabolism via inhibitory phosphorylation of glycogen synthase. Differently from other proteins kinases, GSK-3 isoforms are constitutively active in resting cells, and their modulation mainly involves inhibition through upstream regulatory networks. In the early 1990s, GSK-3 isoforms were implicated as key players in cancer cell pathobiology. Active GSK-3 facilitates the destruction of multiple oncogenic proteins which include β-catenin and Master regulator of cell cycle entry and proliferative metabolism (c-Myc). Therefore, GSK-3 was initially considered to be a tumor suppressor. Consistently, GSK-3 is often inactivated in cancer cells through dysregulated upstream signaling pathways. However, over the past 10–15 years, a growing number of studies highlighted that in some cancer settings GSK-3 isoforms inhibit tumor suppressing pathways and therefore act as tumor promoters. In this article, we will discuss the multiple and often enigmatic roles played by GSK-3 isoforms in some chronic hematological malignancies (chronic myelogenous leukemia, chronic lymphocytic leukemia, multiple myeloma, and B-cell non-Hodgkin’s lymphomas) which are among the most common blood cancer cell types. We will also summarize possible novel strategies targeting GSK-3 for innovative therapies of these disorders.

Insight into the Role of the PI3K/Akt Pathway in Ischemic Injury and Post-Infarct Left Ventricular Remodeling in Normal and Diabetic Heart

Despite the significant decline in mortality, cardiovascular diseases are still the leading cause of death worldwide. Among them, myocardial infarction (MI) seems to be the most important. A further decline in the death rate may be achieved by the introduction of molecularly targeted drugs. It seems that the components of the PI3K/Akt signaling pathway are good candidates for this. The PI3K/Akt pathway plays a key role in the regulation of the growth and survival of cells, such as cardiomyocytes. In addition, it has been shown that the activation of the PI3K/Akt pathway results in the alleviation of the negative post-infarct changes in the myocardium and is impaired in the state of diabetes. In this article, the role of this pathway was described in each step of ischemia and subsequent left ventricular remodeling. In addition, we point out the most promising substances which need more investigation before introduction into clinical practice. Moreover, we present the impact of diabetes and widely used cardiac and antidiabetic drugs on the PI3K/Akt pathway and discuss the molecular mechanism of its effects on myocardial ischemia and left ventricular remodeling.

Acetic acid triggers cytochrome c release in yeast heterologously expressing human Bax

Proteins of the Bcl-2 protein family, including pro-apoptotic Bax and anti-apoptotic Bcl-xL, are critical for mitochondrial-mediated apoptosis regulation. Since yeast lacks obvious orthologs of Bcl-2 family members, heterologous expression of these proteins has been used to investigate their molecular and functional aspects. Active Bax is involved in the formation of mitochondrial outer membrane pores, through which cytochrome c (cyt c) is released, triggering a cascade of downstream apoptotic events. However, when in its inactive form, Bax is largely cytosolic or weakly bound to mitochondria. Given the central role of Bax in apoptosis, studies aiming to understand its regulation are of paramount importance towards its exploitation as a therapeutic target. So far, studies taking advantage of heterologous expression of human Bax in yeast to unveil regulation of Bax activation have relied on the use of artificial mutated or mitochondrial tagged Bax for its activation, rather than the wild type Bax (Bax α). Here, we found that cell death could be triggered in yeast cells heterologoulsy expressing Bax α with concentrations of acetic acid that are not lethal to wild type cells. This was associated with Bax mitochondrial translocation and cyt c release, closely resembling the natural Bax function in the cellular context. This regulated cell death process was reverted by co-expression with Bcl-xL, but not with Bcl-xLΔC, and in the absence of Rim11p, the yeast ortholog of mammalian GSK3β. This novel system mimics human Bax α regulation by GSK3β and can therefore be used as a platform to uncover novel Bax regulators and explore its therapeutic modulation.

The effect of GSK-3β in arsenic-induced apoptosis of malignant tumor cells: a systematic review and meta-analysis

PURPOSE

Arsenic has been reported to induce apoptosis in malignant tumor cells. Therefore, it may be regarded as a treatment for cancers. The mitochondrial apoptosis pathway, mediated by GSK-3β, plays an important role in tumor cell apoptosis. Nonetheless, the regulation of GSK-3β by arsenic remains controversial.

MATERIALS AND METHODS

We included 19 articles, which conducts the role of GSK-3β in the process of arsenic-induced tumor cell apoptosis by the meta-analysis.

RESULTS

Compared with that of control group, the expression of GSK-3β (SMD= -0.92, 95% CI (-1.78, -0.06)), p-Akt (SMD= -5.46,95% CI (-8.67, -2.24)) were increased in the arsenic intervention group. Meanwhile, the combined treatment of arsenic and Akt agonists can inhibit p-GSK-3β. Using the dose and time subgroup analysis, it was shown that the low-dose (<5 μmol/L) and sub-chronic (>24 h) arsenic exposure could inhibit the expression of p-Akt (P < 0.05). In the subgroup analysis of GSK-3β sites, arsenic could inhibit p-Akt and GSK-3β (Ser9) (SMD = -0.95, 95% CI (-1.56, -0.33)). There was a positive dose-response relationship between arsenic and p-GSK-3β when the dose of arsenic was less than 8 μmol/L. The expression of Mcl-1 and pro-caspase-3 were decreased, while the loss of mitochondrial membrane potential and cleaved-caspase-3 increased significantly when arsenic stimulated GSK-3β (Ser9) (P < 0.05).

CONCLUSION

The study revealed that arsenic could induce tumor cell apoptosis, by inhibiting p-Akt/GSK-3β, and triggering the Mcl-1-dependent mitochondrial apoptosis pathway.

GSK-3β inhibition protects human nucleus pulposus cell against oxidative stress-inducing apoptosis through mitochondrial pathway

BACKGROUND

Oxidative stress in the intervertebral disc leads to nucleus pulposus (NP) degeneration by inducing cell apoptosis. However, the molecular mechanisms underlying this process remain unclear. Increasing evidence indicates that GSK-3β is related to cell apoptosis induced by oxidative stress. In this study, we explored whether GSK-3β inhibition protects human NP cell against apoptosis under oxidative stress.

METHODS AND RESULTS

Immunofluorescence staining was used to show the expression of GSK-3β in human NP cells (NPCs). Flow cytometry, mitochondrial staining and western blot (WB) were used to detect apoptosis of treated NPCs, changes of mitochondrial membrane potential and the expression of mitochondrial apoptosis-related proteins using GSK-3β specific inhibitor SB216763. Co-Immunoprecipitation (Co-IP) was used to demonstrate the interaction between GSK-3β and Bcl-2. We delineated the protective effect of GSK-3β specific inhibitor SB216763 on human NPCs apoptosis induced by oxidative stress in vitro. Further, we showed SB216763 exert the protective effect by preservation of the mitochondrial membrane potential and inhibition of caspase 3/7 activity during oxidative injury. The detailed mechanism underlying the antiapoptotic effect of GSK-3β inhibition was also studied by analyzing mitochondrial apoptosis pathway in vitro.

CONCLUSIONS

We concluded that the GSK-3β inhibitor SB216763 protected mitochondrial membrane potential to delay nucleus pulposus cell apoptosis by inhibiting the interaction between GSK-3β and Bcl-2 and subsequently reducing cytochrome c(Cyto-C) release and caspase-3 activation. Together, inhibition of GSK-3β using SB216763 in NPCs may be a favorable therapeutic strategy to slow intervertebral disc degeneration.

Glycogen Synthase Kinase 3β Involvement in Neuroinflammation and Neurodegenerative Diseases

BACKGROUND

GSK-3β activity has been strictly related to neuroinflammation and neurodegeneration. Alzheimer's disease is the most studied neurodegenerative disease, but GSK-3β seems to be involved in almost all neurodegenerative diseases including Parkinson's disease, amyotrophic lateral sclerosis, frontotemporal dementia, Huntington's disease and the autoimmune disease multiple sclerosis.

OBJECTIVE

The aim of this review is to help researchers both working on this research topic or not to have a comprehensive overview on GSK-3β in the context of neuroinflammation and neurodegeneration.

METHOD

Literature has been searched using PubMed and SciFinder databases by inserting specific keywords. A total of more than 500 articles have been discussed.

RESULTS

First of all, the structure and regulation of the kinase were briefly discussed and then, specific GSK-3β implications in neuroinflammation and neurodegenerative diseases were illustrated also with the help of figures, to conclude with a comprehensive overview on the most important GSK-3β and multitarget inhibitors. For all discussed compounds, the structure and IC50 values at the target kinase have been reported.

CONCLUSION

GSK-3β is involved in several signaling pathways both in neurons as well as in glial cells and immune cells. The fine regulation and interconnection of all these pathways are at the base of the rationale use of GSK-3β inhibitors in neuroinflammation and neurodegeneration. In fact, some compounds are now under clinical trials. Despite this, pharmacodynamic and ADME/Tox profiles of the compounds were often not fully characterized and this is deleterious in such a complex system.

Tideglusib Ameliorates Ischemia/Reperfusion Damage by Inhibiting GSK-3β and Apoptosis in Rat Model of Ischemic Stroke

OBJECTIVES

Glycogen synthase kinase-3β (GSK-3β), a serine/threonine protein kinase, gets activated and worsen stroke outcome after ischemia/reperfusion (I/R) injury by inducing inflammation and apoptosis. In this study, tideglusib, a selective irreversible and non-ATP competitive inhibitor of GSK-3β, was explored in cerebral I/R damage using middle cerebral artery occlusion (MCAo) model in rats.

MATERIALS AND METHODS

MCAo was done for 90 min in male Wistar rats (250-280 g) using doccol suture. In pre-treatment group, tideglusib (50 mg/kg) was administered once daily for 2 days and on the day of surgery, 30 min before MCAo. Next day, rats were examined for neurobehavioral parameters and MRI was performed to assess brain damage. In post-treatment group, tideglusib was started at 30 min after MCAo and continued for the next 2 days. After 72 h of MCAo, behavioral parameters and brain damage by MRI were assessed. Further, oxidative stress markers (MDA and GSH), inflammatory cytokines (TNF-α, IL-1β and IL-10) and expression levels of pGSK-3β S9, Bcl-2 and Bax were estimated in pre-treatment group.

RESULTS

Tideglusib pre-treatment but not post-treatment significantly improved neurobehavioral parameters (p < 0.05) and reduced brain damage (p < 0.01) when compared with MCAo group. I/R induced changes in MDA (p < 0.01), TNF-α and IL-1β (p < 0.05) were significantly attenuated by pre-treatment. Further, tideglusib pre-treatment ameliorated MCAo induced altered expressions of pGSK-3β S9, Bcl-2 and Bax.

CONCLUSION

The results of our exploratory study indicated prophylactic potential of tideglusib in I/R injury by modulating pGSK-3β S9, apoptosis and neuro-inflammation.

Diabetes modulation of the myocardial infarction- acute kidney injury axis

Since there is crosstalk in functions of the heart and kidney, acute or chronic injury in one of the two organs provokes adaptive and/or maladaptive responses in both organs, leading to cardiorenal syndrome (CRS). Acute kidney injury (AKI) induced by acute heart failure is referred to as type 1 CRS, and a frequent cause of this type of CRS is acute myocardial infarction (AMI). Diabetes mellitus increases the risk of AMI and also the risk of AKI of various causes. However, there have been only a few studies in which animal models of diabetes were used to examine how diabetes modulates AMI-induced AKI. In this review, we summarize findings regarding the mechanisms of type 1 CRS and the impact of diabetes on both AMI and renal susceptibility to AKI and we discuss mechanisms by which diabetes modulates AMI-induced AKI. Hemodynamic alterations induced by AMI could be augmented by diabetes via its detrimental effect on infarct size and contractile function of the non-infarcted region in the heart. Diabetes increases susceptibility of renal cells to hypoxia and oxidative stress by modulation of signaling pathways that regulate cell survival and autophagy. Recent studies have shown that diabetes mellitus even at early stage of cardiomyopathy/nephropathy predisposes the kidney to AMI-induced AKI, in which activation of toll-like receptors and reactive oxygen species derived from NADPH oxidases are involved. Further analysis of crosstalk between diabetic cardiomyopathy and diabetic kidney disease is necessary for obtaining a more comprehensive understanding of modulation of the AMI-AKI axis by diabetes.

Autophagy and apoptosis cascade: which is more prominent in neuronal death?

Autophagy and apoptosis are two crucial self-destructive processes that maintain cellular homeostasis, which are characterized by their morphology and regulated through signal transduction mechanisms. These pathways determine the fate of cellular organelle and protein involved in human health and disease such as neurodegeneration, cancer, and cardiovascular disease. Cell death pathways share common molecular mechanisms, such as mitochondrial dysfunction, oxidative stress, calcium ion concentration, reactive oxygen species, and endoplasmic reticulum stress. Some key signaling molecules such as p53 and VEGF mediated angiogenic pathway exhibit cellular and molecular responses resulting in the triggering of apoptotic and autophagic pathways. Herein, based on previous studies, we describe the intricate relation between cell death pathways through their common genes and the role of various stress-causing agents. Further, extensive research on autophagy and apoptotic machinery excavates the implementation of selective biomarkers, for instance, mTOR, Bcl-2, BH3 family members, caspases, AMPK, PI3K/Akt/GSK3β, and p38/JNK/MAPK, in the pathogenesis and progression of neurodegenerative diseases. This molecular phenomenon will lead to the discovery of possible therapeutic biomolecules as a pharmacological intervention that are involved in the modulation of apoptosis and autophagy pathways. Moreover, we describe the potential role of micro-RNAs, long non-coding RNAs, and biomolecules as therapeutic agents that regulate cell death machinery to treat neurodegenerative diseases. Mounting evidence demonstrated that under stress conditions, such as calcium efflux, endoplasmic reticulum stress, the ubiquitin-proteasome system, and oxidative stress intermediate molecules, namely p53 and VEGF, activate and cause cell death. Further, activation of p53 and VEGF cause alteration in gene expression and dysregulated signaling pathways through the involvement of signaling molecules, namely mTOR, Bcl-2, BH3, AMPK, MAPK, JNK, and PI3K/Akt, and caspases. Alteration in gene expression and signaling cascades cause neurotoxicity and misfolded protein aggregates, which are characteristics features of neurodegenerative diseases. Excessive neurotoxicity and misfolded protein aggregates lead to neuronal cell death by activating death pathways like autophagy and apoptosis. However, autophagy has a dual role in the apoptosis pathways, i.e., activation and inhibition of the apoptosis signaling. Further, micro-RNAs and LncRNAs act as pharmacological regulators of autophagy and apoptosis cascade, whereas, natural compounds and chemical compounds act as pharmacological inhibitors that rescue neuronal cell death through inhibition of apoptosis and autophagic cell death.

Molecular Signaling to Preserve Mitochondrial Integrity against Ischemic Stress in the Heart: Rescue or Remove Mitochondria in Danger

Cardiovascular diseases are one of the leading causes of death and global health problems worldwide, and ischemic heart disease is the most common cause of heart failure (HF). The heart is a high-energy demanding organ, and myocardial energy reserves are limited. Mitochondria are the powerhouses of the cell, but under stress conditions, they become damaged, release necrotic and apoptotic factors, and contribute to cell death. Loss of cardiomyocytes plays a significant role in ischemic heart disease. In response to stress, protective signaling pathways are activated to limit mitochondrial deterioration and protect the heart. To prevent mitochondrial death pathways, damaged mitochondria are removed by mitochondrial autophagy (mitophagy). Mitochondrial quality control mediated by mitophagy is functionally linked to mitochondrial dynamics. This review provides a current understanding of the signaling mechanisms by which the integrity of mitochondria is preserved in the heart against ischemic stress.

GSK-3β manipulates ferroptosis sensitivity by dominating iron homeostasis

Ferroptosis is a newly characterized form of non-apoptotic-programmed cell death, which is driven by the lethal accumulation of iron-catalyzed lipid peroxides. Uncontrolled ferroptosis is implicated in the pathogenesis of a group of human diseases, while targeted induction of ferroptosis provides a potent therapeutic design for cancers. During the past decade, the fundamental regulatory circuits of ferroptosis have been identified. In this study, we show that the multifaceted Ser/Thr protein kinase GSK-3β acts as a positive modulator of the ferroptosis program. Pharmacological inhibition of GSK-3β by selective inhibitor LY2090314 or genetic KD of GSK-3β by shRNA potently promotes ferroptotic resistance. GSK-3β KD antagonizes the expression of iron metabolic components including DMT1, FTH1, and FTL, leading to the disruption of iron homeostasis and decline in intracellular labile free iron level. Taken together, our findings elaborate an indispensable role of GSK-3β in determining ferroptotic sensitivity by dominating cellular iron metabolism, which provides further insight into GSK-3β as a target for cancer chemotherapy.

Examining the Toxicity of α-Synuclein in Neurodegenerative Disorders

Simple Summary

Neurodegenerative disorders are complex disorders that display a variety of clinical manifestations. The second-most common neurodegenerative disorder is Parkinson’s disease, and the leading pathological protein of the disorder is considered to be α-synuclein. Nonetheless, α-synuclein accumulation also seems to result in multiple system atrophy and dementia with Lewy bodies. In order to obtain a more proficient understanding in the pathological progression of these synucleinopathies, it is crucial to observe the post-translational modifications of α-synuclein and the conformations of α-synuclein, as well as its role in the dysfunction of cellular pathways.

Abstract

α-synuclein is considered the main pathological protein in a variety of neurodegenerative disorders, such as Parkinson’s disease, multiple system atrophy, and dementia with Lewy bodies. As of now, numerous studies have been aimed at examining the post-translational modifications of α-synuclein to determine their effects on α-synuclein aggregation, propagation, and oligomerization, as well as the potential cellular pathway dysfunctions caused by α-synuclein, to determine the role of the protein in disease progression. Furthermore, α-synuclein also appears to contribute to the fibrilization of tau and amyloid beta, which are crucial proteins in Alzheimer’s disease, advocating for α-synuclein’s preeminent role in neurodegeneration. Due to this, investigating the mechanisms of toxicity of α-synuclein in neurodegeneration may lead to a more proficient understanding of the timeline progression in neurodegenerative synucleinopathies and could thereby lead to the development of potent targeted therapies.

FBXL20 promotes breast cancer malignancy by inhibiting apoptosis through degradation of PUMA and BAX

Apoptosis is a programmed cell death that efficiently removes damaged cells to maintain tissue homeostasis. Defect in apoptotic machinery can lead to tumor development, progression, and resistance to chemotherapy. PUMA (p53 upregulated modulator of apoptosis) and BAX (BCL2-associated X protein) are among the most well-known inducers of apoptosis. It has been reported that expression levels of BAX and PUMA are controlled at the posttranslational level by phosphorylation. However, the posttranslational regulation of these proapoptotic proteins remains largely unexplored. In this study, using biochemical, molecular biology, flow cytometric, and immunohistochemistry techniques, we show that PUMA and BAX are the direct target of the F-box protein FBXL20, which restricts their cellular levels. FBXL20 directs the proteasomal degradation of PUMA and BAX in a protein kinase AKT1-dependent manner to promote cancer cell proliferation and tumor growth. Interestingly, inactivation of AKT1 results in activation of another protein kinase GSK3α/β, which facilitates the proteasomal degradation of FBXL20 by another F-box protein, FBXO31. Thus, a switch between two signaling kinases AKT1 and GSK3α/β modulates the functional activity of these proapoptotic regulators, thereby determining cell survival or death. RNAi-mediated ablation of FBXL20 results in increased levels of PUMA as well as BAX, which further enhances the sensitivity of cancer cells to chemotherapeutic drugs. We showed that high level expression of FBXL20 in cancer cells reduces therapeutic drug-induced apoptosis and promotes chemoresistance. Overall, this study highlights the importance of targeting FBXL20 in cancers in conjunction with chemotherapy and may represent a promising anticancer strategy to overcome chemoresistance.

Curcumin and Nano-Curcumin Mitigate Copper Neurotoxicity by Modulating Oxidative Stress, Inflammation, and Akt/GSK-3β Signaling

Copper (Cu) is essential for multiple biochemical processes, and copper sulphate (CuSO₄) is a pesticide used for repelling pests. Accidental or intentional intoxication can induce multiorgan toxicity and could be fatal. Curcumin (CUR) is a potent antioxidant, but its poor systemic bioavailability is the main drawback in its therapeutic uses. This study investigated the protective effect of CUR and N-CUR on CuSO₄-induced cerebral oxidative stress, inflammation, and apoptosis in rats, pointing to the possible involvement of Akt/GSK-3β. Rats received 100 mg/kg CuSO₄ and were concurrently treated with CUR or N-CUR for 7 days. Cu-administered rats exhibited a remarkable increase in cerebral malondialdehyde (MDA), NF-κB p65, TNF-α, and IL-6 associated with decreased GSH, SOD, and catalase. Cu provoked DNA fragmentation, upregulated BAX, caspase-3, and p53, and decreased BCL-2 in the brain of rats. N-CUR and CUR ameliorated MDA, NF-κB p65, and pro-inflammatory cytokines, downregulated pro-apoptotic genes, upregulated BCL-2, and enhanced antioxidants and DNA integrity. In addition, both N-CUR and CUR increased AKT Ser473 and GSK-3β Ser9 phosphorylation in the brain of Cu-administered rats. In conclusion, N-CUR and CUR prevent Cu neurotoxicity by attenuating oxidative injury, inflammatory response, and apoptosis and upregulating AKT/GSK-3β signaling. The neuroprotective effect of N-CUR was more potent than CUR.

Review: Schistosoma mansoni phosphatidylinositol 3 kinase (PI3K)/Akt/mechanistic target of rapamycin (mTOR) signaling pathway

Schistosoma mansoni worms are under a milieu of external and internal signaling pathways. The life-cycle stages are exposed to enormous stimuli within the mammalian and the snail hosts and as free-living stages in the fresh water. Furthermore, there is a unique interplay between the male and the female worms involving many stimuli from the male essential for full development of the female. PI3K/Akt/mTOR is an evolutionarily divergent signal transduction pathway universal to nearly every multicellular organism. This work reviews the Schistosoma mansoni PI3K/Akt/mTOR signal pathways and the involvement of the signal in the worms' physiology concerning the uptake of glucose, reproduction and survival. The inhibitors of the signal pathway used against Schistosoma mansoni were summarized. Given the importance of the PI3K/Akt/mTOR signal pathway, its inhibition could be a promising control strategy against schistosomiasis.

Effect of Visnagin on Altered Steroidogenesis and Spermatogenesis, and Testicular Injury Induced by the Heavy Metal Lead

BACKGROUND

Lead (Pb) is an environmental pollutant causing serious health problems, including impairment of reproduction. Visnagin (VIS) is a furanochromone with promising antioxidant and anti-inflammatory effects; however, its protective efficacy against Pb toxicity has not been investigated.

OBJECTIVE

This study evaluated the protective effect of VIS on Pb reproductive toxicity, impaired steroidogenesis and spermatogenesis, oxidative stress and inflammation.

METHODS

Rats received VIS (30 or 60 mg/kg) and 50 mg/kg lead acetate for 3 weeks and blood and testes samples were collected.

RESULTS

Pb intoxication impaired the pituitary-testicular axis (PTA) manifested by the decreased serum levels of gonadotropins and testosterone. Pb decreased sperm count, motility and viability, increased sperm abnormalities, and downregulated the steroidogenesis markers StAR, CYP17A1, 3β-HSD and 17β-HSD in the testis of rats. VIS significantly increased serum gonadotropins and testosterone, alleviated sperm parameters and upregulated steroidogenesis. In addition, VIS decreased pro-inflammatory cytokines, testicular lipid peroxidation and DNA fragmentation, downregulated Bax, and enhanced antioxidants and Bcl-2.

CONCLUSION

These results demonstrate the protective effect of VIS against Pb reproductive toxicity in rats. VIS improved serum gonadotropins and testosterone, enhanced steroidogenesis and spermatogenesis, and attenuated oxidative injury, inflammation and apoptosis. Therefore, VIS is a promising candidate for the protection against Pb-induced reproduction impairment.

AKT signaling restrains tumor suppressive functions of FOXO transcription factors and GSK3 kinase in multiple myeloma

The phosphatidylinositide-3 kinases and the downstream mediator AKT drive survival and proliferation of multiple myeloma (MM) cells. AKT signaling is active in MM and has pleiotropic effects; however, the key molecular aspects of AKT dependency in MM are not fully clear. Among the various downstream AKT targets are the Forkhead box O (FOXO) transcription factors (TFs) and glycogen synthase kinase 3 (GSK3), which are negatively regulated by AKT signaling. Here we show that abrogation of AKT signaling in MM cells provokes cell death and cell cycle arrest, which crucially depends on both FOXO TFs and GSK3. Based on gene expression profiling, we defined a FOXO-repressed gene set that has prognostic significance in a large cohort of patients with MM, indicating that AKT-mediated gene activation is associated with inferior overall survival. We further show that AKT signaling stabilizes the antiapoptotic myeloid cell leukemia 1 (MCL1) protein by inhibiting FOXO- and GSK3-mediated MCL1 turnover. In concordance, abrogation of AKT signaling greatly sensitized MM cells for an MCL1-targeting BH3-mimetic, which is currently in clinical development. Taken together, our results indicate that AKT activity is required to restrain the tumor-suppressive functions of FOXO and GSK3, thereby stabilizing the antiapoptotic protein MCL1 in MM. These novel insights into the role of AKT in MM pathogenesis and MCL1 regulation provide opportunities to improve targeted therapy for patients with MM.

Natural products as pharmacological modulators of mitochondrial dysfunctions for the treatments of Alzheimer's disease: A comprehensive review

Alzheimer's disease (AD) is the most common progressive neurodegenerative disorder characterized by neuronal loss and cognitive impairment that harshly affect the elderly individuals. Currently, the available anti-AD pharmacological approaches are purely symptomatic to alleviate AD symptoms, and the curative effects of novel anti-AD drugs focused on Aβ target are disappointing. Hence, there is a tremendous need to adjust AD therapeutic targets and discover novel anti-AD agents. In AD, mitochondrial dysfunction gradually triggers neuronal death from different aspects and worsens the occurrence and progress of AD. Consequently, it has been proposed that the intervention of impaired mitochondria represents an attractive breakthrough point for AD treatments. Due to chemical diversity, poly-pharmacological activities, few adverse effects and multiple targeting, natural products (NPs) have been identified as a valuable treasure for drug discovery and development. Multiple lines of studies have scientifically proven that NPs display ameliorative benefits in AD treatment in relation to mitochondrial dysfunction. This review surveys the complicated implications for mitochondrial dysregulation and AD, and then summarizes the potentials of NPs and their underlying molecular mechanisms against AD via reducing or improving mitochondrial dysfunction. It is expected that this work may open the window to speed up the development of innovative anti-AD drugs originated from NPs and improve upcoming AD therapeutics.

The role of glycogen synthase kinase 3 (GSK3) in cancer with emphasis on ovarian cancer development and progression: A comprehensive review

Glycogen synthase kinase 3 (GSK3) is a monomeric serine-threonine kinase discovered in 1980 in a rat skeletal muscle. It has been involved in various cellular processes including embryogenesis, immune response, inflammation, apoptosis, autophagy, wound healing, neurodegeneration, and carcinogenesis. GSK3 exists in two different isoforms, GSK3α and GSK3β, both containing seven antiparallel beta-plates, a short linking part and an alpha helix, but coded by different genes and variously expressed in human tissues. In the current review, we comprehensively appraise the current literature on the role of GSK3 in various cancers with emphasis on ovarian carcinoma. Our findings indicate that the role of GSK3 in ovarian cancer development cannot be decisively determined as the currently available data support both prooncogenic and tumor-suppressive effects. Likewise, the clinical impact of GSK3 expression on ovarian cancer patients and its potential therapeutic implications are also limited. Further studies are needed to fully elucidate the pathophysiological and clinical implications of GSK3 activity in ovarian cancer.

Interaction between Parkin and α-Synuclein in PARK2-Mediated Parkinson's Disease

Parkin and α-synuclein are two key proteins involved in the pathophysiology of Parkinson's disease (PD). Neurotoxic alterations of α-synuclein that lead to the formation of toxic oligomers and fibrils contribute to PD through synaptic dysfunction, mitochondrial impairment, defective endoplasmic reticulum and Golgi function, and nuclear dysfunction. In half of the cases, the recessively inherited early-onset PD is caused by loss of function mutations in the PARK2 gene that encodes the E3-ubiquitin ligase, parkin. Parkin is involved in the clearance of misfolded and aggregated proteins by the ubiquitin-proteasome system and regulates mitophagy and mitochondrial biogenesis. PARK2-related PD is generally thought not to be associated with Lewy body formation although it is a neuropathological hallmark of PD. In this review article, we provide an overview of post-mortem neuropathological examinations of PARK2 patients and present the current knowledge of a functional interaction between parkin and α-synuclein in the regulation of protein aggregates including Lewy bodies. Furthermore, we describe prevailing hypotheses about the formation of intracellular micro-aggregates (synuclein inclusions) that might be more likely than Lewy bodies to occur in PARK2-related PD. This information may inform future studies aiming to unveil primary signaling processes involved in PD and related neurodegenerative disorders.

Mechanisms and Therapeutic Implications of GSK-3 in Treating Neurodegeneration

Neurodegenerative disorders are spreading worldwide and are one of the greatest threats to public health. There is currently no adequate therapy for these disorders, and therefore there is an urgent need to accelerate the discovery and development of effective treatments. Although neurodegenerative disorders are broad ranging and highly complex, they may share overlapping mechanisms, and thus potentially manifest common targets for therapeutic interventions. Glycogen synthase kinase-3 (GSK-3) is now acknowledged to be a central player in regulating mood behavior, cognitive functions, and neuron viability. Indeed, many targets controlled by GSK-3 are critically involved in progressing neuron deterioration and disease pathogenesis. In this review, we focus on three pathways that represent prominent mechanisms linking GSK-3 with neurodegenerative disorders: cytoskeleton organization, the mammalian target of rapamycin (mTOR)/autophagy axis, and mitochondria. We also consider the challenges and opportunities in the development of GSK-3 inhibitors for treating neurodegeneration.

Mitochondrial Kinases and the Role of Mitochondrial Protein Phosphorylation in Health and Disease

The major role of mitochondria is to provide cells with energy, but no less important are their roles in responding to various stress factors and the metabolic changes and pathological processes that might occur inside and outside the cells. The post-translational modification of proteins is a fast and efficient way for cells to adapt to ever changing conditions. Phosphorylation is a post-translational modification that signals these changes and propagates these signals throughout the whole cell, but it also changes the structure, function and interaction of individual proteins. In this review, we summarize the influence of kinases, the proteins responsible for phosphorylation, on mitochondrial biogenesis under various cellular conditions. We focus on their role in keeping mitochondria fully functional in healthy cells and also on the changes in mitochondrial structure and function that occur in pathological processes arising from the phosphorylation of mitochondrial proteins.

Umbelliferone Inhibits Spermatogenic Defects and Testicular Injury in Lead-Intoxicated Rats by Suppressing Oxidative Stress and Inflammation, and Improving Nrf2/HO-1 Signaling

INTRODUCTION

Lead (Pb) is an environmental toxic metal that threatens human health. Umbelliferone (UMB) is a coumarin with known medicinal and protective properties against cytotoxicity. This study explored the ameliorative effect of UMB against Pb-induced testicular toxicity in rats, focusing on steroidogenesis, oxidative stress and inflammation.

MATERIALS AND METHODS

Rats received lead acetate (50 mg/kg) and UMB (25, 50 or 100 mg/kg) via oral gavage for 4 weeks.

RESULTS

Pb-intoxicated rats exhibited testicular tissue injury and decreased serum levels of LH, FSH and testosterone. The count, viability, motility and normal morphology of the sperms were decreased accompanied with downregulated steroidogenesis markers in Pb-induced group. UMB prevented testicular injury, increased serum levels of LH, FSH and testosterone, upregulated steroidogenesis markers and improved the semen quality. In addition, UMB attenuated oxidative stress and oxidative DNA damage, downregulated the expression of pro-inflammatory mediators and Bax, boosted antioxidant defenses and Bcl-2, and upregulated Nrf2/HO-1 signaling in Pb-intoxicated rats.

CONCLUSION

UMB prevents Pb-induced testicular injury by suppressing oxidative damage, inflammation and cell death, and boosting antioxidant defenses, Nrf2/HO-1 signaling and pituitary-gonadal axis. Thus, UMB may represent a protective and cost-effective agent against Pb testicular toxicity, pending further investigations to elucidate other underlying mechanisms.

Latest perspectives on glucocorticoid-induced apoptosis and resistance in lymphoid malignancies

Glucocorticoids are essential drugs in the treatment protocols of lymphoid malignancies. These steroidal hormones trigger apoptosis of the malignant cells by binding to the glucocorticoid receptor (GR), which is a member of the nuclear receptor superfamily. Long term glucocorticoid treatment is limited by two major problems: the development of glucocorticoid-related side effects, which hampers patient quality of life, and the emergence of glucocorticoid resistance, which is a gradual process that is inevitable in many patients. This emphasizes the need to reevaluate and optimize the widespread use of glucocorticoids in lymphoid malignancies. To achieve this goal, a deep understanding of the mechanisms governing glucocorticoid responsiveness is required, yet, a recent comprehensive overview is currently lacking. In this review, we examine how glucocorticoids mediate apoptosis by detailing GR's genomic and non-genomic action mechanisms in lymphoid malignancies. We continue with a discussion of the glucocorticoid-related problems and how these are intertwined with one another. We further zoom in on glucocorticoid resistance by critically analyzing the plethora of proposed mechanisms and highlighting therapeutic opportunities that emerge from these studies. In conclusion, early detection of glucocorticoid resistance in patients remains an important challenge as this would result in a timelier treatment reorientation and reduced glucocorticoid-instigated side effects.

Astragaloside IV Derivative (LS-102) Alleviated Myocardial Ischemia Reperfusion Injury by Inhibiting Drp1Ser616 Phosphorylation-Mediated Mitochondrial Fission

Our previous studies showed that Astragaloside IV derivative (LS-102) exhibited potent protective function against ischemia reperfusion (I/R) injury, but little is known about the mechanisms. Mitochondrial fission regulated by dynamin-related protein1 (Drp1) is a newly recognized determinant of mitochondrial function. This study aimed to investigate the protection of LS-102 on mitochondrial structure and function by regulating the activity of Drp1 using models of H9c2 cardiomyocyte injury induced by hypoxia-reperfusion (H/R), and rat heart injury induced by I/R. The results showed that LS-102 significantly decreased apoptosis, levels of ROS, CK, LDH, and calcium, upregulating MMP, and the Bax/Bcl-2 ratio in cardiomyocytes during I/R injury. Furthermore, LS-102 prevented I/R-induced mitochondrial fission by decreasing Drp1's mitochondrial localization through decreasing the phosphorylation of Drp1 at Ser616 (Drp1Ser616) and increasing the phosphorylation of Drp1 at Ser637 (Drp1Ser637) in H9c2 cells. Importantly, we also robustly confirmed Drp1Ser616 as a novel GSK-3β phosphorylation site. GSK-3β-mediated phosphorylation at Drp1Ser616 may be associated with mitochondrial fission during I/R of cardiomyocytes. In conclusion, LS-102 exerts cardio protection against I/R-induced injury by inhibiting mitochondrial fission via blocking GSK-3β-mediated phosphorylation at Ser616 of Drp1.

Alcohol Use Disorder, Neurodegeneration, Alzheimer's and Parkinson's Disease: Interplay Between Oxidative Stress, Neuroimmune Response and Excitotoxicity

Alcohol use disorder (AUD) has been associated with neurodegenerative diseases such as Alzheimer's and Parkinson's disease. Prolonged excessive alcohol intake contributes to increased production of reactive oxygen species that triggers neuroimmune response and cellular apoptosis and necrosis via lipid peroxidation, mitochondrial, protein or DNA damage. Long term binge alcohol consumption also upregulates glutamate receptors, glucocorticoids and reduces reuptake of glutamate in the central nervous system, resulting in glutamate excitotoxicity, and eventually mitochondrial injury and cell death. In this review, we delineate the following principles in alcohol-induced neurodegeneration: (1) alcohol-induced oxidative stress, (2) neuroimmune response toward increased oxidants and lipopolysaccharide, (3) glutamate excitotoxicity and cell injury, and (4) interplay between oxidative stress, neuroimmune response and excitotoxicity leading to neurodegeneration and (5) potential chronic alcohol intake-induced development of neurodegenerative diseases, including Alzheimer's and Parkinson's disease.

Phosphorylated GSK‑3β protects stress‑induced apoptosis of myoblasts via the PI3K/Akt signaling pathway

Facial jaw muscle is involved in the occurrence, development, treatment and maintenance of maxillofacial deformities. The structure and function of this tissue can be altered by changes in external stimuli, and orthodontists can regulate its reconstruction using orthopedic forces. The PI3K/Akt signaling pathway is most well‑known for its biological functions in cell proliferation, survival and apoptosis. In the present study, the effects of the PI3K/Akt signaling pathway in cyclic stretch‑induced myoblast apoptosis were investigated. For this purpose, L6 rat myoblasts were cultured under mechanical stimulation and treated with the PI3K kinase inhibitor, LY294002, to elucidate the role of the PI3K/Akt signaling pathway. Cells were stained with Hoechst 33258 to visualize morphological changes and apoptosis of myoblasts, and western blotting was performed to detect expression of Akt, phosphorylated (p)‑Akt (Ser473), glycogen synthase kinase 3β (GSK‑3β) and p‑GSK‑3β (Ser9). After addition of PI3K inhibitor, the expression of total Akt and GSK‑3β did not significantly differ among groups; however, the levels of p‑Akt and p‑GSK‑3β were lower in inhibitor‑treated groups than in those treated with loading stress alone. In addition, the rate of apoptosis in myoblasts subjected to cyclic stretch increased in a time‑dependent manner, peaking at 24 h. Collectively, it was also demonstrated that the PI3K/Akt/GSK‑3β pathway plays an important role in stretch‑induced myoblast apoptosis.

QTC-4-MeOBnE Rescues Scopolamine-Induced Memory Deficits in Mice by Targeting Oxidative Stress, Neuronal Plasticity, and Apoptosis

Cognitive decline and memory impairment induced by disruption of cholinergic neurons and oxidative brain damage are among the earliest pathological hallmark signatures of Alzheimer's disease. Scopolamine is a postsynaptic muscarinic receptor blocker which causes impairment of cholinergic transmission resulting in cognitive deficits. Herein we investigated the effect of QTC-4-MeOBnE (1-(7-chloroquinolin-4-yl)-N-(4-methoxybenzyl)-5-methyl-1H-1,2,3-triazole-4-carboxamide) on memory impairments in mice chronically treated with scopolamine and the molecular mechanisms involved. Administration of scopolamine (1 mg/kg) for 15 days resulted in significant impairments in working and short-term memory in mice, as assessed by the novel object recognition and the Y-maze paradigms. However, both deficits were prevented if mice receiving the scopolamine were also treated with QTC-4-MeOBnE. This effect was associated with an increase in antioxidant enzymes (superoxide dismutase and catalase), a reduction in lipid peroxidation, and an increase in Nrf2 expression. Moreover, brains from QTC-4-MeOBnE treated mice had a significant decrease in acetylcholinesterase activity and glycogen synthase kinase-3β levels but an increase in brain-derived neurotrophic factor and Bcl-2 expression levels. Taken together our findings demonstrate that the beneficial effect of QTC-4-MeOBnE in a mouse model of scopolamine-induced memory impairment is mediated via the involvement of different molecular pathways including oxidative stress, neuroplasticity, neuronal vulnerability, and apoptosis. Our study provides further evidence on the promising therapeutic potential of QTC-4-MeOBnE as a multifactorial disease modifying drug in AD and related dementing disorders.

Eupatilin prevents behavioral deficits and dopaminergic neuron degeneration in a Parkinson's disease mouse model

AIMS

Neuroinflammation and apoptosis play a crucial role in Parkinson's disease (PD) pathogenesis. Eupatilin is a lipophilic flavonoid isolated from Artemisia species and exerts anti-apoptotic and anti-inflammatory activities. In this study, we investigated the effects of Eupatilin on a mouse model of PD induced by 1-methyl-4-phenyl-1,2,3,6-tetrahydropyridine (MPTP).

MAIN METHODS

The rotarod test and traction test were constructed to examine the motor function. Immunofluorescent staining was performed to detect the expression of TH, Iba-1 and GFAP. Apoptosis was examined by the TUNEL assay. Real-time PCR was used to determine the mRNA expression and Western blot and ELISA were used to determine the protein expression.

KEY FINDINGS

Eupatilin improved behavioral impairment caused by MPTP. A loss of TH positive neurons was observed in the substantia nigra pars compacta of MPTP-lesioned brain, while it was rescued by Eupatilin. Moreover, MPTP administration increased the cell number of microglia and astrocytes and the expression of inflammatory factors TNF-α, IL-1β, and IL-6. Whereas Eupatilin suppressed the activation of neuroinflammation. Eupatilin also decreased cell apoptosis enhanced by MPTP/MPP⁺ exposure in vivo and in vitro. We further revealed that Eupatilin abolished MPTP-induced downregulation of IκBα expression and accumulation of p65 in the nuclear compartment. Besides, MPTP administration led to dephosphorylation of Akt and GSK-3β, but it was restored by Eupatilin.

SIGNIFICANCE

We demonstrate that Eupatilin alleviates behavioral impairment and dopaminergic neuron loss induced by MPTP through inhibition of neuroinflammation and apoptosis. Our research provides more evidence for Eupatilin as a potential preventative drug for PD.