Phosphorylation Of GSK-3β Research Articles

ADAMTS16 Suppression by MicroRNA-25 Leads to Oncogenic Properties in Renal Cell Carcinoma.

Increasing evidence indicates that microRNAs (miRNAs) play a crucial role in modulating tumor growth. This study is centered on investigating the contribution of miR-25 to the progression of Renal Cell Carcinoma (RCC). The investigators examined the expression levels of miR-25 and ADAMTS16 in RCC samples and cell lines. The association between miR-25 and ADAMTS16 was validated via a luciferase reporter assay. Cell viability, apoptosis, migration, and invasion were evaluated utilizing CCK-8 and flow cytometry techniques, while the expression levels of ADAMTS16, β-catenin, GSK-3β, and p-GSK-3β were assessed through western blot analysis. The investigation revealed elevated expression levels of miR-25 in RCC tissues. Subsequently, ADAMTS16 was identified as a target of miR-25. Increased miR-25 levels were associated with decreased expression of ADAMTS16, resulting in enhanced cell viability and diminished apoptosis. Conversely, inhibition of miR-25 led to decreased cell viability, proliferation, and migration. Additionally, the researchers observed that miR-25 triggered the phosphorylation of GSK-3β and β-catenin while leaving the total GSK-3β level unaffected. This study suggests that miR-25 regulates the expression of ADAMTS16 through the Wnt/β-catenin signaling pathway, providing new insights into the cause and potential treatment of RCC.

1-Deoxynojirimycin attenuates pathological markers of Alzheimer's disease in the invitro model of neuronal insulin resistance.

Insulin resistance, the hallmark of type 2 diabetes mellitus (T2DM), has emerged as a pathological feature in Alzheimer's disease (AD). Given the shared role of insulin resistance in T2DM and AD, repurposing peripheral insulin sensitizers is a promising strategy to preserve neuronal insulin sensitivity and prevent AD. 1-Deoxynojirimycin (DNJ), a bioactive iminosugar, exhibited insulin-sensitizing effects in metabolic tissues and was detected in brain tissue post-oral intake. However, its impact on brain and neuronal insulin signaling has not been described. Here, we investigated the effect of DNJ treatment on insulin signaling and AD markers in insulin-resistant human SK-N-SH neuroblastoma, a cellular model of neuronal insulin resistance. Our findings show that DNJ increased the expression of insulin signaling genes and the phosphorylation status of key molecules implicated in insulin resistance (Y1146-pIRβ, S473-pAKT, S9-GSK3B) while also elevating the expression of glucose transporters Glut3 and Glut4, resulting in higher glucose uptake upon insulin stimuli. DNJ appeared to mitigate the insulin resistance-driven increase in phosphorylated tau and Aβ1-42 levels by promoting insulin-induced phosphorylation of GSK3B (a major tau kinase) and enhancing mRNA expression of the insulin-degrading enzyme (IDE) pivotal for insulin and Aβ clearance. Overall, our study unveils probable mechanisms underlying the potential benefits of DNJ for AD, wherein DNJ attenuates tau and amyloid pathologies by reversing neuronal insulin resistance. This provides a scientific basis for expanding the use of DNJ-containing products for neuroprotective purposes and prompts further research into compounds with similar mechanisms of action.

AP collagen peptides (APCPs) promote hair growth by activating the GSK-3β/β-catenin pathway and improve hair condition.

AP collagen peptides (APCPs) are enzymatically decomposed collagen peptides that contain tri-peptides such as glycine-proline-hydroxyproline. We found that APCPs increased the proliferation of both human dermal papilla cells (hDPCs) and human outer root sheath cells (hORSCs). APCPs also stimulated the secretion of several growth factors, including IGFBP-6, PDGF-AB, PIGF and VEGF in hDPCs. Moreover, APCPs enhanced the phosphorylation of Akt(Ser473), GSK-3β(Ser9) and β-catenin(Ser675), indicating the activation of the GSK-3β/β-catenin signalling pathway. Exvivo culture of human hair follicles (hHFs) tissue and invivo patch assay revealed that APCPs promoted the elongation of hHFs and the induction of new hair shafts. In a mouse model, APCPs significantly promoted the transition from telogen to anagen phase and prolonged anagen phase, resulting in increased hair growth. APCPs also improved the thickness, amino acid content (cystine and methionine) and roughness of mouse hair. Taken together, these findings demonstrate that APCPs accelerate hair growth and contribute to overall hair health. Therefore, APCPs have the potential to be utilized as a food supplement and ingredient for preventing hair loss and maintaining hair health.

Bone Marrow Mesenchymal Stem Cells Promote Ovarian Cancer Cell Proliferation via Cytokine Interactions.

Bone marrow mesenchymal stem cells (BMSCs) are key players in promoting ovarian cancer cell proliferation, orchestrated by the dynamic interplay between cytokines and their interactions with immune cells; however, the intricate crosstalk among BMSCs and cytokines has not yet been elucidated. Here, we aimed to investigate interactions between BMSCs and ovarian cancer cells. We established BMSCs with a characterized morphology, surface marker expression, and tri-lineage differentiation potential. Ovarian cancer cells (SKOV3) cultured with conditioned medium from BMSCs showed increased migration, invasion, and colony formation, indicating the role of the tumor microenvironment in influencing cancer cell behavior. BMSCs promoted SKOV3 tumorigenesis in nonobese diabetic/severe combined immunodeficiency mice, increasing tumor growth. The co-injection of BMSCs increased the phosphorylation of p38 MAPK and GSK-3β in SKOV3 tumors. Co-culturing SKOV3 cells with BMSCs led to an increase in the expression of cytokines, especially MCP-1 and IL-6. These findings highlight the influence of BMSCs on ovarian cancer cell behavior and the potential involvement of specific cytokines in mediating these effects. Understanding these mechanisms will highlight potential therapeutic avenues that may halt ovarian cancer progression.

Exploring the effects of naringin on oxidative stress-impaired osteogenic differentiation via the Wnt/β-catenin and PI3K/Akt pathways

This study aimed to explore naringin’s potential to promote the osteogenic differentiation of MC3T3-E1 under oxidative stress. It delved into Nar’s connection with the Wnt/β-catenin and PI3K/Akt signaling pathways. Initially, 2911 OP-related genes were analyzed, revealing close ties with the PI3K/Akt and Wnt pathways alongside oxidative stress. Nar’s potential targets—ESR1, HSP90AA1, and ESR2—were identified through various databases and molecular docking studies confirmed Nar’s affinity with ESR1 and HSP90AA1. Experiments established optimal concentrations for Nar and H2O2. H2O2 at 0.3 mmol/L damaged MC3T3-E1 cells, alleviated by 0.1 µmol/L Nar. Successful establishment of oxidative stress models was confirmed by DCFH-DA probe and NO detection. Nar exhibited the ability to enhance osteogenic differentiation, counteracting oxidative damage. It notably increased osteoblast-related protein expression in MC3T3-E1 cells under oxidative stress. The study found Nar’s positive influence on GSK-3β phosphorylation, β-catenin accumulation, and pathway-related protein expression, all critical in promoting osteogenic differentiation. The research concluded that Nar effectively promotes osteogenic differentiation in MC3T3-E1 cells under oxidative stress. It achieved this by activating the Wnt/β-catenin and PI3K/Akt pathways, facilitating GSK-3β phosphorylation, and enhancing β-catenin accumulation, pivotal in osteogenesis.

REDD1 Deletion Suppresses NF-κB Signaling in Cardiomyocytes and Prevents Deficits in Cardiac Function in Diabetic Mice.

Activation of the transcription factor NF-κB in cardiomyocytes has been implicated in the development of cardiac function deficits caused by diabetes. NF-κB controls the expression of an array of pro-inflammatory cytokines and chemokines. We recently discovered that the stress response protein regulated in development and DNA damage response 1 (REDD1) was required for increased pro-inflammatory cytokine expression in the hearts of diabetic mice. The studies herein were designed to extend the prior report by investigating the role of REDD1 in NF-κB signaling in cardiomyocytes. REDD1 genetic deletion suppressed NF-κB signaling and nuclear localization of the transcription factor in human AC16 cardiomyocyte cultures exposed to TNFα or hyperglycemic conditions. A similar suppressive effect on NF-κB activation and pro-inflammatory cytokine expression was also seen in cardiomyocytes by knocking down the expression of GSK3β. NF-κB activity was restored in REDD1-deficient cardiomyocytes exposed to hyperglycemic conditions by expression of a constitutively active GSK3β variant. In the hearts of diabetic mice, REDD1 was required for reduced inhibitory phosphorylation of GSK3β at S9 and upregulation of IL-1β and CCL2. Diabetic REDD1+/+ mice developed systolic functional deficits evidenced by reduced ejection fraction. By contrast, REDD1-/- mice did not exhibit a diabetes-induced deficit in ejection fraction and left ventricular chamber dilatation was reduced in diabetic REDD1-/- mice, as compared to diabetic REDD1+/+ mice. Overall, the results support a role for REDD1 in promoting GSK3β-dependent NF-κB signaling in cardiomyocytes and in the development of cardiac function deficits in diabetic mice.

Biliverdin Reductase-A integrates insulin signaling with mitochondrial metabolism through phosphorylation of GSK3β

Brain insulin resistance links the failure of energy metabolism with cognitive decline in both type 2 Diabetes Mellitus (T2D) and Alzheimer's disease (AD), although the molecular changes preceding overt brain insulin resistance remain unexplored. Abnormal biliverdin reductase-A (BVR-A) levels were observed in both T2D and AD and were associated with insulin resistance. Here, we demonstrate that reduced BVR-A levels alter insulin signaling and mitochondrial bioenergetics in the brain. Loss of BVR-A leads to IRS1 hyper-activation but dysregulates Akt-GSK3β complex in response to insulin, hindering the accumulation of pGSK3βS9 into the mitochondria. This event impairs oxidative phosphorylation and fosters the activation of the mitochondrial Unfolded Protein Response (UPRmt). Remarkably, we unveil that BVR-A is required to shuttle pGSK3βS9 into the mitochondria. Our data sheds light on the intricate interplay between insulin signaling and mitochondrial metabolism in the brain unraveling potential targets for mitigating the development of brain insulin resistance and neurodegeneration.

Pharmacokinetic study and neuropharmacological effects of atractylenolide Ⅲ to improve cognitive impairment via PI3K/AKT/GSK3β pathway in intracerebroventricular-streptozotocin rats

Ethnopharmacological relevanceThe traditional Chinese herbal remedy Atractylodes macrocephala Koidz is renowned for its purported gastrointestinal regulatory properties and immune-enhancing capabilities. Atractylenolide III (ATL III), a prominent bioactive compound in Atractylodes macrocephala Koidz, has demonstrated significant pharmacological activities. However, its impact on neuroinflammation, oxidative stress, and therapeutic potential concerning Alzheimer's disease (AD) remain inadequately investigated.Aim of the study: This study aims to assess the plasma pharmacokinetics of ATL III in Sprague-Dawley (SD) rats and elucidate its neuropharmacological effects on AD via the PI3K/AKT/GSK3β pathway. Through this research, we endeavor to furnish experimental substantiation for the advancement of novel therapeutics centered on ATL III. Materials and methodsThe pharmacokinetic profile of ATL III in SD rat plasma was analyzed using liquid chromatography-tandem mass spectrometry (LC-MS/MS). AD models were induced in SD rats through bilateral intracerebroventricular (ICV) administration of streptozotocin (STZ). ATL III was administered at doses of 0.6 mg/kg, 1.2 mg/kg, and 2.4 mg/kg, while donepezil (1 mg/kg) served as control. Cognitive function assessments were conducted employing behavioral tests including the Morris Water Maze and Novel Object Recognition. Neuronal pathology and histological changes were evaluated through Nissl staining and Hematoxylin-Eosin (HE) staining, respectively. Oxidative stress levels were determined by quantifying malondialdehyde (MDA) content and total superoxide dismutase (T-SOD) activity. Molecular docking analysis was employed to explore the direct binding between ATL III and its relevant targets, followed by validation using Western blot (WB) experiments to assess the expression of p-Tau, PI3K, AKT, GSK3β, and their phosphorylated forms. ResultsWithin the concentration range of 5–500 ng/mL, ATL III demonstrated exceptional linearity (R2 = 0.9991), with a quantification limit of 5 ng/mL. In male SD rats, ATL III exhibited a Tmax of 45 min, a t1/2 of 172.1 min, a Cmax of 1211 ng/L, and an AUC(0-t) of 156031 ng/L*min. Treatment with ATL III significantly attenuated Tau hyperphosphorylation in intracerebroventricular-streptozotocin (ICV-STZ) rats. Furthermore, ATL III administration mitigated neuroinflammation and oxidative stress, as evidenced by reduced Nissl body loss, alleviated histological alterations, decreased MDA content, and enhanced T-SOD activity. Molecular docking analyses revealed strong binding affinity between ATL III and the target genes PI3K, AKT, and GSK3β. Experimental validation corroborated that ATL III stimulated the phosphorylation of PI3K and AKT while reducing the phosphorylation of GSK3β. ConclusionsOur results indicate that ATL III can mitigate Tau protein phosphorylation through modulation of the PI3K/AKT/GSK3β pathway. This attenuation consequently ameliorates neuroinflammation and oxidative stress, leading to enhanced learning and memory abilities in ICV-STZ rats.

Apigenin alleviates doxorubicin-induced myocardial pyroptosis by inhibiting glycogen synthase kinase-3β in vitro and in vivo.

Apigenin, a natural flavonoid compound found in chamomile (Matricaia chamomilla L.) from the Asteraceae family, has been shown in our previous study to possess antimyocardial hypertrophy and anti-cardiac fibrosis effects. However, its effects and mechanisms on the pyroptosis of cardiomyocytes induced by doxorubicin (DOX) are poorly understood. The objective of this study was to investigate the role of GSK-3β and the effects of apigenin in DOX-induced cardiotoxicity. H9c2 cells stimulated with DOX were treated with SB216763 and apigenin. Additionally, a mouse model of DOX-induced cardiotoxicity was prepared and further treated with apigenin and SB216763 for 30 days. The findings revealed that treatment with SB216763 or apigenin resulted in a significant reduction in the levels of pyroptosis-related factors. Furthermore, the phosphorylation of GSK-3β was enhanced while the phosphorylation of nuclear factor-kB (NF-κB) p65 was reduced following treatment with either SB216763 or apigenin. Conversely, the effects of apigenin treatment were nullified in siRNA-GSK-3β-transfected cells. Results from computer simulation and molecular docking analysis supported that apigenin could directly target the regulation of GSK-3β. Therefore, our study confirmed that the inhibition of GSK-3β and treatment with apigenin effectively suppressed the pyroptosis of cardiomyocytes in both DOX-stimulated H9c2 cells and mice. These benefits may be attributed in part to the decrease in GSK-3β expression and subsequent reduction in NF-κB p65 activation. Overall, our findings revealed that the pharmacological targeting of GSK-3β may offer a promising therapeutic approach for alleviating DOX-induced cardiotoxicity.

Mechanisms of vascular inflammaging: TNF-alpha mediates endothelial CEACAM1 expression by NF-KB and beta-Catenin in a biphasic manner

Abstract Funding Acknowledgements Type of funding sources: Foundation. Main funding source(s): German Research Foundation Introduction Chronic inflammation with progressive age, also called inflammaging, is a hallmark of the pathogenesis of cardiovascular diseases. Previously we have shown increased expression of the Carcinoembryonic antigen-related cell adhesion molecule 1 (CEACAM1) with progressive age in the vasculature of mice and humans that leads to a chronic pro-inflammatory milieu via mutual upregulation with TNF-α. Furthermore, CEACAM1 critically promotes vascular aging processes like collagen deposition, endothelial permeability as well as enhanced oxidative stress. Therefore, CEACAM1 is a main mediator of vascular inflammaging that may facilitate progress into cardiovascular diseases. In this study we identified the mechanisms that underly the upregulation of endothelial CEACAM1 expression by TNF-α in detail. Methods Wildtype (WT) and TNF-α knockout (Tnf-/-) mice of different age were used to determine the impact of TNF-α on age-dependent CEACAM1 expression in vivo. Underlying mechanisms of TNF-α-dependent CEACAM1 upregulation were further analyzed in an endothelial cell culture model using pharmacological inhibition and siRNA-mediated knockdown of signaling pathways. Activation of signaling pathways was confirmed by determining the phosphorylation status of signaling components via Western Blot and analysis of nuclear translocation of NF-κB and β-Catenin using subcellular fractionation. Results Immunohistochemical analyses of aortic sections from WT and Tnf-/- mice of different age reveal that TNF-α critically contributes to the aging-related upregulation of endothelial CEACAM1 expression in vivo. Mechanistic analyses in vitro showed that TNF-α upregulated CEACAM1 expression in a time-dependent manner. In pharmacological experiments we identified an early NF-κB- and a delayed β-Catenin-mediated response. This finding was supported by time-matched nuclear translocation of NF-κB and β-Catenin. Furthermore, siRNA-mediated knockdown of the β-Catenin-targeted transcription factor TCF4 reduced TNF-α-mediated CEACAM1 upregulation. Co-immunoprecipitation analyses show that β-Catenin is released by TNF-α-mediated adherens junctions disassembly. Furthermore, TNF-α enhanced activating phosphorylation of Akt kinase at Ser473. Akt kinase in turn increased phosphorylation of β-Catenin at Ser552, a modification reported to augment its transcriptional activity. Additionally, Akt kinase facilitated β-Catenin signaling by inhibition of its degradation via phosphorylation of GSK3β at Ser9. Conclusion Taken together, this study identified the signaling mechanisms that underly the vascular upregulation of CEACAM1 with age. Our results directly link endothelial barrier impairment, an initial step in the pathogenesis of atherosclerosis, to CEACAM1 expression. Since CEACAM1 critically promotes vascular inflammaging and age-dependent vascular alterations this further emphasizes the potential of CEACAM1 as a novel target to prevent cardiovascular diseases.

Hair growth-promoting effects of Enz_MoriL on human dermal papilla cells through modulation of the Wnt/β-Catenin and JAK-STAT signaling pathways.

Enz_MoriL is a naturally occurring substance extracted from the leaves of Morus alba L. through enzymatic conversion. Historically, M. alba L. has been recognized for its potential to promote hair regrowth. However, the precise mechanism by which Enz_MoriL affects human hair follicle dermal papilla cells (hDPCs) remains unclear. The aim of this study was to investigate the molecular basis of Enz_MoriL's effect on hair growth in hDPCs. Interferon-gamma (IFN-γ) was used to examine the effects of Enz_MoriL on hDPCs during the anagen and catagen phases, as well as under conditions mimicking alopecia areata (AA). Enz_MoriL demonstrated the ability to promote cell proliferation in both anagen and catagen stages. It increased the levels of active β-catenin in the catagen stage induced by IFN-γ, leading to its nuclear translocation. This effect was achieved by increasing the phosphorylation of GSK3β and decreasing the expression of DKK-1. This stimulation induced proliferation in hDPCs and upregulated the expression of the Wnt family members 3a, 5a, and 7a at the transcript level. Additionally, Enz_MoriL suppressed JAK1 and STAT3 phosphorylation, contrasting with IFN-γ, which induced them in the catagen stage. In conclusion, Enz_MoriL directly induced signals for anagen re-entry into hDPCs by affecting the Wnt/β-catenin pathway and enhancing the production of growth factors. Furthermore, Enz_MoriL attenuated and reversed the interferon-induced AA-like environment by blocking the JAK-STAT pathway in hDPCs.

Antifibrotic effect of the P2X7 receptor antagonist A740003 against acute myocardial infarction-induced fibrotic remodelling

Post-acute myocardial infarction (AMI) fibrosis is a pathophysiologic process characterised by activation of the profibrotic mediator, transforming growth factor-β (TGF-β). AMI is associated with a substantial increase in the levels of extracellular adenosine triphosphate (eATP), which acts on the purinergic P2X7-receptor (P2X7-R) and triggers an inflammatory response that contributes to myocardial fibrotic remodelling. P2X7-R has been implicated in several cardiovascular diseases; however, its role in the regulation of cardiac fibrosis remains unclear. Therefore, the current study aimed to determine the effect of the P2X7-R antagonist, A740003, on post-AMI fibrosis, via the profibrotic TGF-β1/Smad signalling pathway, and elucidate whether its effect is mediated via the modulation of GSK-3β. AMI was induced by surgical ligation of the left anterior descending coronary artery, Thereafter, animals were divided into groups: sham control, MI-untreated, MI-vehicle, and MI-A740003 (50 mg/kg/day) and treated for seven days accordingly. The heart weight/body weight ratio of untreated-ligated rats significantly increased by 15.1 %, creatine kinase‐MB (CK‐MB) significantly increased by 40 %, troponin‐I levels significantly increased by 25.4 %, and lactate dehydrogenase significantly increased by 47.2 %, indicating myocardial damage confirmed by morphological changes and massive cardiac fibrosis. The protein expression of cardiac fibronectin, TGF-β1, and p-Smad2 were also upregulated by 143 %, 40 %, and 8 %, respectively, indicating cardiac fibrosis. The treatment of ligated rats with A740003 led to improvement in all the above-mentioned parameters. Overall, A740003 exhibits potential cardio-protective effects on post-AMI fibrotic remodelling in the animal model of AMI through P2X7-R blockade, possibly by downregulating the profibrotic TGF-β1/Smad signalling pathway and restoring GSK-3β phosphorylation. Altogether, treatment with A740003 could serve as a new cardioprotective strategy to attenuate post-AMI fibrotic remodelling.

Mitochondrial translation failure represses cholesterol gene expression via Pyk2-Gsk3β-Srebp2 axis.

Neurodegenerative diseases and other age-related disorders are closely associated with mitochondrial dysfunction. We previously showed that mice with neuron-specific deficiency of mitochondrial translation exhibit leukoencephalopathy because of demyelination. Reduced cholesterol metabolism has been associated with demyelinating diseases of the brain such as Alzheimer's disease. However, the molecular mechanisms involved and relevance to the pathogenesis remained unknown. In this study, we show that inhibition of mitochondrial translation significantly reduced expression of the cholesterol synthase genes and degraded their sterol-regulated transcription factor, sterol regulatory element-binding protein 2 (Srebp2). Furthermore, the phosphorylation of Pyk2 and Gsk3β was increased in the white matter of p32cKO mice. We observed that Pyk2 inhibitors reduced the phosphorylation of Gsk3β and that GSK3β inhibitors suppressed degradation of the transcription factor Srebp2. The Pyk2-Gsk3β axis is involved in the ubiquitination of Srebp2 and reduced expression of cholesterol gene. These results suggest that inhibition of mitochondrial translation may be a causative mechanism of neurodegenerative diseases of aging. Improving the mitochondrial translation or effectiveness of Gsk3β inhibitors is a potential therapeutic strategy for leukoencephalopathy.

Proton pump inhibitors stabilize the expression of PD-L1 on cell membrane depending on the phosphorylation of GSK3β.

Preclinical and clinical evidence indicates that proton pump inhibitors (PPIs) may indirectly diminish the microbiome diversity, thereby reducing the effectiveness of immune checkpoint inhibitors (ICIs). Conversely, recent publications have shown that PPIs could potentially enhance the response to ICIs. The precise mechanism through which PPIs modulate the ICIs remains unclear. In this study, we discovered a novel molecular function of PPIs in regulating immune invasion, specifically through inducing PD-L1 translocation in various tumor cells. C57BL/6 mice subcutaneous transplantation model is used to verify the potential efficacy of PPIs and PD-L1 antibody. Western blotting analysis and phosphorylated chip are used to verify the alteration of PD-L1-related pathways after being treated with PPIs. The related gene expression is performed by qRT-PCR and luciferase reporter analysis. We also collected 60 clinical patients diagnosed with esophageal cancer or reflux esophagitis and then detected the expression of PD-L1 in the tissue samples by immunohistochemistry. We observed that the IC50 of tumor cells in response to PPIs was significantly higher than that of normal epithelial cells. PPIs significantly increased the expression of PD-L1 on cell membrane at clinically relevant concentrations. Furthermore, pre-treatment with PPIs appeared to synergize the efficiency of anti-PD-L1 antibodies in mouse models. However, PPI administration did not alter the transcription or total protein level of PD-L1 in multiple tumor cells. Using a phosphorylated protein chip, we identified that PPIs enhanced the phosphorylation of GSK3β, then leading to PD-L1 protein translocation to the cell membranes. The capacity of PPIs to upregulate PD-L1 was negated following GSK3β knockout. Furthermore, our clinical data showed that the PPIs use resulted in increased PD-L1 expression in esophageal cancer patients. We mainly address a significant and novel mechanism that the usage of PPIs could directly induce the expression of PD-L1 by inducing GSK3β phosphorylation and facilitate primary tumor progression and metastasis.

Corydaline alleviates Parkinson's disease by regulating autophagy and GSK-3β phosphorylation.

Jitai tablet, a traditional Chinese medicine, has a neuroprotective effect on 1-methyl-4-phenyl-1, 2, 3, 6-tetrahydropyridine (MPTP)-induced Parkinson's disease (PD) mice. As one of the main active ingredients in the Jitai tablet, corydaline (Cory) has analgesic and anti-allergic effects, but it has not been studied in PD. Here, we investigated the role and mechanism of Cory in PD. The PD model was induced by MPTP. Cell viability was measured by 3-(4, 5)-dimethylthiahiazo (-z-y1)-3, 5-di-phenytetrazoliumromide assay. The Pole test and traction test were performed to detect the behaviors of mice. The expression of tyrosine hydroxylase (Th) was detected by immunohistochemistry and Western blot. Immunofluorescence staining, monodansylcadaverine staining, and Western blot were conducted to assess autophagy. A lactic dehydrogenase release assay was used to detect cytotoxicity. Network pharmacology was used to screen the targets. There existed cytotoxicity when the concentration of Cory reached 40μg/mL. Cory (not exceeding 20μg/mL) could alleviate MPTP-induced cell damage. In vivo experiments indicated that Cory could improve the motor coordination of mice with PD. Besides, Cory could increase LC3-II/LC3-I levels both in vivo and in vitro. In addition, the Th levels reduced in the striatum and middle brain tissues of Parkinson's mice were recovered by Cory injection. We also found that Cory decreased the phosphorylation of glucogen synthase kinase-3 beta (GSK-3β) at Tyr216 and increased the phosphorylation of GSK-3β at Ser9 not only in primary neurons and SH-SY5Y cells but also in the striatum and middle brain tissues. Furthermore, Cory increased LC3-II/LC3-I levels and decreased p62 levels by regulating GSK-3β. Cory enhanced autophagy, attenuated MPTP-induced cytotoxicity, and alleviated PD partly through the regulation of GSK-3β phosphorylation.

β-Hydroxybutyrate Recapitulates the Beneficial Effects of Time-Restricted Feeding and Periodic Fasting in Multiple Rodent Models of Polycystic Kidney Disease

Polycystic kidney disease is a monogenic disease caused predominantly by mutations in the PKD1 or PKD2 genes. These mutations result in the formation of large fluid-filled cysts derived from kidney epithelial cells that slowly replace functional healthy tissue. Affected kidneys rely heavily on glycolysis to meet energy demands, and is accompanied by a reduction in fatty acid oxidation and mitochondrial function. We previously reported that interventions inducing a state of ketosis, including caloric restriction, time-restricted feeding (TRF), ketogenic diet, extended fasting, and ketone supplementation, ameliorate or reverse polycystic kidney disease progression in multiple animal models. To elaborate on the capability of ketosis to alter disease progression, we compared, head-to-head, the effects of a daily 16:8 TRF regimen to periodic 48-hour fasting (PF) in both juvenile and adult Cy/+ rats. We found that alternative fasting interventions prevent juvenile disease progression and partially reverse established kidney disease in adults. Further, to test our hypothesis that an increase in β-hydroxybutyrate (BHB) may mediate these beneficial effects, we administered BHB to adult Cy/+ rats and stereospecific isomers to two orthologous mouse models of PKD ( P kd1RC/RC, Pkd1-Ksp:Cre). BHB recapitulates the effects of fasting in these models independent of stereoisomer, reducing mTORC1 signaling, increasing GSK-3β phosphorylation, expression and translocation of Nuclear factor erythroid 2-related factor 2 (Nrf2) in cystic epithelia, and subsequent downstream targets of Nrf2. These findings extend and expand our previous report on the beneficial effects of ketosis on cystic disease progression and suggest that ketogenic metabolic interventions and BHB supplementation are capable of metabolic reprogramming in polycystic kidney disease. This work was supported by grants from the NIH (Grants R01DK109563, R01DK124895) and the US Department of Defense (Grant W81XWH2010827) to T.W., and gifts from the Amy P. Goldman Foundation and the Jarrett Family Fund to University of California, Santa Barbara, to support the work of T.W. The MRL Shared Experimental Facilities are supported by the MRSEC Program of the NSF under Award No. DMR 1720256; a member of the NSF-funded Materials Research Facilities Network (www.mrfn.org). This is the full abstract presented at the American Physiology Summit 2024 meeting and is only available in HTML format. There are no additional versions or additional content available for this abstract. Physiology was not involved in the peer review process.

Titanium dioxide nanoparticles oral exposure induce osteoblast apoptosis, inhibit osteogenic ability and increase lipogenesis in mouse

Titanium dioxide nanoparticles (TiO2-NPs) are widely used in food, paint, coating, cosmetic, and composite orthodontic material. As a common food additive, TiO2-NPs can accumulate in various organs of human body, but the effect and underlying mechanism of bone remain unclear. Here mice were exposed to TiO2-NPs by oral gavage, and histological staining of femoral sections showed that TiO2-NPs reduced bone formation and enhanced osteoclast activity and lipogenesis, contributing to decreased trabecula bone. Transmission electron microscope (TEM) as well as biochemical and flow cytometry analysis of osteoblast exhibited that TiO2-NPs accumulated in osteoblast cytoplasm and impaired mitochondria ultrastructure with increased reactive oxygen species (ROS) and lipid hyperoxide, resulting in osteoblast apoptosis. In terms of mechanism, TiO2-NPs treatment inhibited expression of AKT and then increased pro-apoptotic protein Bax expression which was failure to form heterodimers with decreased anti-apoptotic Bcl-2, activating downstream Caspase-9 and Caspase-3 and inducing apoptosis. Additionally, TiO2-NPs suppressed Wnt3a level and then activated anti-Glycogen synthesis kinase (GSK-3β) phosphorylation, and ultimately resulted in degradation of β-catenin which down-regulated Runt-related transcription factor 2 (Runx2) and Osterix, inhibiting expression of osteogenic related proteins. Together, these results revealed that exposure of TiO2-NPs induced apoptosis and inhibited osteoblast differentiation through suppressing PI3K/AKT and Wnt/β-catenin signaling pathways, resulting in reduction of trabecula bone.

Impact of Prospero Homeobox-1 (PROX-1) οn the Oncogenic Phenotypes of Hepatocellular Carcinoma Cells.

Transcriptional factor prospero homeobox-1 (PROX-1) is crucial for the embryonic development of various organs and cell fate specification. It exhibits either an oncogenic or tumor suppressive activity depending on cancer types. However, the relationship between PROX-1 and hepatocellular carcinoma (HCC) remains obscure. This study was conducted to investigate the effect of PROX-1 on the invasive and oncogenic phenotypes of human HCC cells. The effect of PROX-1 on tumor cell behavior was investigated by using a pcDNA-myc vector and a small interfering RNA in HepG2 and Huh7 human HCC cell lines. Flow cytometry, migration, invasion, proliferation, and tube formation assays were performed. PROX-1 expression in human HCC cells was explored by western blotting. PROX-1 overexpression enhanced tumor cell proliferation and inhibited apoptosis and cell cycle arrest by modulating the activities of caspase-3, PARP, and cyclin-dependent kinase inhibitors, including p21, p27, and p57 in HCC cells. After PROX-1 overexpression, the number of migrating and invading HCC cells significantly increased, and the expression levels of N-cadherin and Snail increased in HCC cells. PROX-1 overexpression enhanced angiogenesis through increased VEGF-A and VEGF-C expression and decreased angiostatin expression. PROX-1 overexpression also increased the phosphorylation of glycogen synthase kinase-3β (GSK-3β) and forkhead box O1 (FOXO1) in HCC cells. After PROX-1 knockdown, their phosphorylation was reversed. PROX-1 overexpression is associated with the invasive and oncogenic phenotypes of human HCC cells via GSK-3β and FOXO1 phosphorylation.

D-mannose targets PD-1 to lysosomal degradation and enhances T cell-mediated anti-tumor immunity

High expression of programmed cell death protein 1 (PD-1), a typical immune checkpoint, results in dysfunction of T cells in tumor microenvironment. Antibodies and inhibitors against PD-1 or its ligand (PD-L1) have been widely used in various malignant tumors. However, the mechanisms by which PD-1 is regulated are not fully understood. Here, we report a mechanism of PD-1 degradation triggered by d-mannose and the universality of this mechanism in anti-tumor immunity. We show that d-mannose inactivates GSK3β via promoting phosphorylation of GSK3β at Ser9, thereby leading to TFE3 translocation to nucleus and subsequent PD-1 proteolysis induced by enhanced lysosome biogenesis. Notably, combination of d-mannose and PD-1 blockade exhibits remarkable tumor growth suppression attributed to elevated cytotoxicity activity of T cells in vivo. Furthermore, d-mannose treatment dramatically improves the therapeutic efficacy of MEK inhibitor (MEKi) trametinib in vivo. Our findings unveil a universally unrecognized anti-tumor mechanism of d-mannose by destabilizing PD-1 and provide strategies to enhance the efficacy of both immune checkpoint blockade (ICB) and MEKi -based therapies.

LRP1 facilitates hepatic glycogenesis by improving the insulin signaling pathway in HFD-fed mice.

LDL receptor-related protein-1 (LRP1) is a cell-surface receptor that functions in diverse physiological pathways. We previously demonstrated that hepatocyte-specific LRP1 deficiency (hLRP1KO) promotes diet-induced insulin resistance and increases hepatic gluconeogenesis in mice. However, it remains unclear whether LRP1 regulates hepatic glycogenesis. Insulin signaling, glycogenic gene expression, and glycogen content were assessed in mice and HepG2 cells. The pcDNA 3.1 plasmid and adeno-associated virus serotype 8 vector (AAV8) were used to overexpress the truncated β-chain (β∆) of LRP1 both invitro and invivo. On a normal chow diet, hLRP1KO mice exhibited impaired insulin signaling and decreased glycogen content. Moreover, LRP1 expression in HepG2 cells was significantly repressed by palmitate in a dose- and time-dependent manner. Both LRP1 knockdown and palmitate treatment led to reduced phosphorylation of Akt and GSK3β, increased levels of phosphorylated glycogen synthase (GYS), and diminished glycogen synthesis in insulin-stimulated HepG2 cells, which was restored by exogenous expression of the β∆-chain. By contrast, AAV8-mediated hepatic β∆-chain overexpression significantly improved the insulin signaling pathway, thus activating glycogenesis and enhancing glycogen storage in the livers of high-fat diet (HFD)-fed mice. Our data revealed that LRP1, especially its β-chain, facilitates hepatic glycogenesis by improving the insulin signaling pathway, suggesting a new therapeutic strategy for hepatic insulin resistance-related diseases.