Structural and functional effects of phosphopriming and scaffolding in the kinase GSK-3ß.

Glycogen synthase kinase 3ß (GSK-3ß) targets specific signaling pathways in response to distinct upstream signals. We used structural and functional studies to dissect how an upstream phosphorylation step primes the Wnt signaling component ß-catenin for phosphorylation by GSK-3ß and how scaffolding interactions contribute to this reaction. Our crystal structure of GSK-3ß bound to a phosphoprimed ß-catenin peptide confirmed the expected binding mode of the phosphoprimed residue adjacent to the catalytic site. An aspartate phosphomimic in the priming site of ß-catenin adopted an indistinguishable structure but reacted approximately 1000-fold slower than the native phosphoprimed substrate. This result suggests that substrate positioning alone is not sufficient for catalysis and that native phosphopriming interactions are necessary. We also obtained a structure of GSK-3ß with an extended peptide from the scaffold protein Axin that bound with greater affinity than that of previously crystallized Axin fragments. This structure neither revealed additional contacts that produce the higher affinity nor explained how substrate interactions in the GSK-3ß active site are modulated by remote Axin binding. Together, our findings suggest that phosphopriming and scaffolding produce small conformational changes or allosteric effects, not captured in the crystal structures, that activate GSK-3ß and facilitate ß-catenin phosphorylation. These results highlight limitations in our ability to predict catalytic activity from structure and have potential implications for the role of natural phosphomimic mutations in kinase regulation and phosphosite evolution.

PIM1 kinase promotes EMT-associated osimertinib resistance via regulating GSK3ß signaling pathway in EGFR-mutant non-small cell lung cancer.

Acquired resistance is inevitable in the treatment of non-small cell lung cancer (NSCLC) with osimertinib, and one of the primary mechanisms responsible for this resistance is the epithelial-mesenchymal transition (EMT). We identify upregulation of the proviral integration site for Moloney murine leukemia virus 1 (PIM1) and functional inactivation of glycogen synthase kinase 3ß (GSK3ß) as drivers of EMT-associated osimertinib resistance. Upregulation of PIM1 promotes the growth, invasion, and resistance of osimertinib-resistant cells and is significantly correlated with EMT molecules expression. Functionally, PIM1 suppresses the ubiquitin-proteasome degradation of snail family transcriptional repressor 1 (SNAIL) and snail family transcriptional repressor 2 (SLUG) by deactivating GSK3ß through phosphorylation. The stability and accumulation of SNAIL and SLUG facilitate EMT and encourage osimertinib resistance. Furthermore, treatment with PIM1 inhibitors prevents EMT progression and re-sensitizes osimertinib-resistant NSCLC cells to osimertinib. PIM1/GSK3ß signaling is activated in clinical samples of osimertinib-resistant NSCLC, and dual epidermal growth factor receptor (EGFR)/PIM1 blockade synergistically reverse osimertinib-resistant NSCLC in vivo. These data identify PIM1 as a driver of EMT-associated osimertinib-resistant NSCLC cells and predict that PIM1 inhibitors and osimertinib combination therapy will provide clinical benefit in patients with EGFR-mutant NSCLC.

Association Between Type 2 Diabetes Mellitus and Alzheimer's Disease: Common Molecular Mechanism and Therapeutic Targets.

Diabetes mellitus (DM) and Alzheimer's disease (AD) rates are rising, mirroring the global trend of an aging population. Numerous epidemiological studies have shown that those with Type 2 diabetes (T2DM) have an increased risk of developing dementia. These degenerative and progressive diseases share some risk factors. To a large extent, the amyloid cascade is responsible for AD development. Neurofibrillary tangles induce neurodegeneration and brain atrophy; this chain reaction begins with hyperphosphorylation of tau proteins caused by progressive amyloid beta (Aß) accumulation. In addition to these processes, it seems that alterations in brain glucose metabolism and insulin signalling lead to cell death and reduced synaptic plasticity in AD, before the onset of symptoms, which may be years away. Due to the substantial evidence linking insulin resistance in the brain with AD, researchers have coined the name "Type 3 diabetes" to characterize the condition. We still know little about the processes involved, even though current animal models have helped illuminate the links between T2DM and AD. This brief overview discusses insulin and IGF-1 signalling disorders and the primary molecular pathways that may connect them. The presence of GSK-3ß in AD is intriguing. These proteins' association with T2DM and pancreatic ß-cell failure suggests they might be therapeutic targets for both disorders.

Concomitant targeting of FLT3 and SPHK1 exerts synergistic cytotoxicity in FLT3-ITD+ acute myeloid leukemia by inhibiting ß-catenin activity via the PP2A-GSK3ß axis.

BACKGROUND: Approximately 25-30% of patients with acute myeloid leukemia (AML) have FMS-like receptor tyrosine kinase-3 (FLT3) mutations that contribute to disease progression and poor prognosis. Prolonged exposure to FLT3 tyrosine kinase inhibitors (TKIs) often results in limited clinical responses due to diverse compensatory survival signals. Therefore, there is an urgent need to elucidate the mechanisms underlying FLT3 TKI resistance. Dysregulated sphingolipid metabolism frequently contributes to cancer progression and a poor therapeutic response. However, its relationship with TKI sensitivity in FLT3-mutated AML remains unknown. Thus, we aimed to assess mechanisms of FLT3 TKI resistance in AML. METHODS: We performed lipidomics profiling, RNA-seq, qRT-PCR, and enzyme-linked immunosorbent assays to determine potential drivers of sorafenib resistance. FLT3 signaling was inhibited by sorafenib or quizartinib, and SPHK1 was inhibited by using an antagonist or via knockdown. Cell growth and apoptosis were assessed in FLT3-mutated and wild-type AML cell lines via Cell counting kit-8, PI staining, and Annexin-V/7AAD assays. Western blotting and immunofluorescence assays were employed to explore the underlying molecular mechanisms through rescue experiments using SPHK1 overexpression and exogenous S1P, as well as inhibitors of S1P2, ß-catenin, PP2A, and GSK3ß. Xenograft murine model, patient samples, and publicly available data were analyzed to corroborate our in vitro results. RESULTS: We demonstrate that long-term sorafenib treatment upregulates SPHK1/sphingosine-1-phosphate (S1P) signaling, which in turn positively modulates ß-catenin signaling to counteract TKI-mediated suppression of FLT3-mutated AML cells via the S1P2 receptor. Genetic or pharmacological inhibition of SPHK1 potently enhanced the TKI-mediated inhibition of proliferation and apoptosis induction in FLT3-mutated AML cells in vitro. SPHK1 knockdown enhanced sorafenib efficacy and improved survival of AML-xenografted mice. Mechanistically, targeting the SPHK1/S1P/S1P2 signaling synergizes with FLT3 TKIs to inhibit ß-catenin activity by activating the protein phosphatase 2 A (PP2A)-glycogen synthase kinase 3ß (GSK3ß) pathway. CONCLUSIONS: These findings establish the sphingolipid metabolic enzyme SPHK1 as a regulator of TKI sensitivity and suggest that combining SPHK1 inhibition with TKIs could be an effective approach for treating FLT3-mutated AML.

GSK3ß Inhibitors Inhibit TGFß Signaling in the Human Trabecular Meshwork.

Purpose: Primary open-angle glaucoma (POAG) is a leading cause of blindness, and its primary risk factor is elevated intraocular pressure (IOP) due to pathologic changes in the trabecular meshwork (TM). We previously showed that there is a cross-inhibition between TGFß and Wnt signaling pathways in the TM. In this study, we determined if activation of the Wnt signaling pathway using small-molecule Wnt activators can inhibit TGFß2-induced TM changes and ocular hypertension (OHT). Methods: Primary human TM (pHTM) cells and transduced SBE-GTM3 cells were treated with or without Wnt and/or TGFß signaling activators and used for luciferase assays; for the extraction of whole-cell lysate, conditioned medium, cytosolic proteins, and nuclear proteins for Western immunoblotting (WB); or for immunofluorescent staining. Human donor eyes were perfusion cultured to study the effect of Wnt activators on IOP. Results: We found that the small-molecule Wnt activators (GSK3ß inhibitors) (BIO, SB216763, and CHIR99021) activated canonical Wnt signaling in pHTM cells without toxicity at tested concentrations. This activation inhibited TGFß signaling as well as TGFß2-induced extracellular matrix deposition and formation of cross-linked actin networks in pHTM cells or SBE-GTM3 cells. We also observed nuclear translocation of both Smad4 and ß-catenin in pHTM cells, which suggested that the cross-inhibition between the TGFß and Wnt signaling pathways may occur in the nucleus. Using our ex vivo model, we found that CHIR99021 inhibited TGFß2-induced OHT in perfusion-cultured human eyes. Conclusions: Our results showed that small-molecule Wnt activators have the potential for treating TGFß signaling-induced OHT in patients with POAG.

Accumulated ß-catenin is associated with human atrial fibrosis and atrial fibrillation.

BACKGROUND: Atrial fibrillation (AF) is associated with increased risk of stroke and mortality. It has been reported that the process of atrial fibrosis was regulated by ß-catenin in rats with AF. However, pathophysiological mechanisms of this process in human with AF remain unclear. This study aims to investigate the possible mechanisms of ß-catenin in participating in the atrial fibrosis using human right atrial appendage (hRAA) tissues . METHODS: We compared the difference of ß-catenin expression in hRAA tissues between the patients with AF and sinus rhythm (SR). The possible function of ß-catenin in the development of AF was also explored in mice and primary cells. RESULTS: Firstly, the space between the membrane of the gap junctions of cardiomyocytes was wider in the AF group. Secondly, the expression of the gap junction function related proteins, Connexin40 and Connexin43, was decreased, while the expression of ß-catenin and its binding partner E-cadherin was increased in hRAA and cardiomyocytes of the AF group. Thirdly, ß-catenin colocalized with E-cadherin on the plasma membrane of cardiomyocytes in the SR group, while they were dissociated and accumulated intracellularly in the AF group. Furthermore, the expression of glycogen synthase kinase 3ß (GSK-3ß) and Adenomatous Polyposis Coli (APC), which participated in the degradation of ß-catenin, was decreased in hRAA tissues and cardiomyocytes of the AF group. Finally, the development of atrial fibrosis and AF were proved to be prevented after inhibiting ß-catenin expression in the AF model mice. CONCLUSIONS: Based on human atrial pathological and molecular analyses, our findings provided evidence that ß-catenin was associated with atrial fibrosis and AF progression.

Pterostilbene Ameliorates Cognitive Impairment in Polycystic Ovary Syndrome Rat Model through Improving Insulin Resistance via the IRS-1/PI3K/Akt/GSK-3ß Pathway: A Comparative Study with Metformin.

Polycystic ovary syndrome (PCOS) is an intricate endocrine disorder that targets millions of women globally. Recent research has drawn attention to its association with cognitive impairment and Alzheimer's disease (AD) risk, yet the exact mechanism remains elusive. This study aimed to explore the potential role of PCOS-associated insulin resistance (IR) and inflammation in linking PCOS to AD pathogenesis. It additionally investigated the therapeutic merits of pterostilbene (PTS) in ameliorating PCOS and associated cognitive deficits in comparison to metformin (MET). Rats were divided into five groups; vehicle group, PTS group [30 mg/kg, per os (p.o.) for 13 days], and the remaining three groups received letrozole (1 mg/kg, p.o. for 21 days) to represent the PCOS, PCOS + MET (300 mg/kg, p.o. for 13 days), and PCOS + PTS groups, respectively. Behavioral tests were conducted, along with a histopathological investigation of brains and ovaries. Assessment of serum hormonal profile and hippocampal IRS-1/PI3K/AKT/GSK-3ß insulin signaling pathway components were performed. PTS rats exhibited improved insulin sensitivity and hormonal profile, besides enhanced neurobehavioral tests performance and histopathological findings. These effects may be attributed to modulation of the IRS-1/PI3K/AKT/GSK-3ß pathway, reducing GSK-3ß activity, and mitigating Tau hyperphosphorylation and Aß accumulation in the brain. Likewise, PTS attenuated nuclear factor kappa B-mediated inflammation and reversed AChE elevation, suggesting multifaceted neuroprotective effects. Comparatively, PTS showed outcomes similar to those of MET in most parameters. The obtained findings validated that dysregulated insulin signaling in PCOS rats detrimentally affects cognitive function, which is halted by PTS, unveiling the potential of PTS as a novel therapy for PCOS and related cognitive deficits.

Natural compounds from herbs and nutraceuticals as glycogen synthase kinase-3ß inhibitors in Alzheimer's disease treatment.

BACKGROUND: Alzheimer's disease (AD) pathogenesis is complex. The pathophysiology is not fully understood, and safe and effective treatments are needed. Glycogen synthase kinase 3ß (GSK-3ß) mediates AD progression through several signaling pathways. Recently, several studies have found that various natural compounds from herbs and nutraceuticals can significantly improve AD symptoms. AIMS: This review aims to provide a comprehensive summary of the potential neuroprotective impacts of natural compounds as inhibitors of GSK-3ß in the treatment of AD. MATERIALS AND METHODS: We conducted a systematic literature search on PubMed, ScienceDirect, Web of Science, and Google Scholar, focusing on in vitro and in vivo studies that investigated natural compounds as inhibitors of GSK-3ß in the treatment of AD. RESULTS: The mechanism may be related to GSK-3ß activation inhibition to regulate amyloid beta production, tau protein hyperphosphorylation, cell apoptosis, and cellular inflammation. By reviewing recent studies on GSK-3ß inhibition in phytochemicals and AD intervention, flavonoids including oxyphylla A, quercetin, morin, icariin, linarin, genipin, and isoorientin were reported as potent GSK-3ß inhibitors for AD treatment. Polyphenols such as schisandrin B, magnolol, and dieckol have inhibitory effects on GSK-3ß in AD models, including in vivo models. Sulforaphene, ginsenoside Rd, gypenoside XVII, falcarindiol, epibrassinolides, 1,8-Cineole, and andrographolide are promising GSK-3ß inhibitors. CONCLUSIONS: Natural compounds from herbs and nutraceuticals are potential candidates for AD treatment. They may qualify as derivatives for development as promising compounds that provide enhanced pharmacological characteristics.

hUMSCs restore ovarian function in POI mice by regulating GSK3ß-mediated mitochondrial dynamic imbalances in theca cells.

Premature ovarian insufficiency (POI), a major cause of female infertility, is defined as follicular atresia and a rapid loss of germ cells in women of reproductive age due to ovarian failure. Recently, findings from several studies have indicated that human umbilical cord mesenchymal stem cells (hUMSCs) can alleviate ovarian dysfunction resulting from POI. However, the mechanisms underlying this effect require further clarification. In this study, a mouse model of POI was established as achieved with an intraperitoneal injection of cyclophosphamide (CTX) into female C57BL/6J mice in vivo. These POI mice received a 1-week intervention of hUMACs. In addition, an in vitro POI model was also included. The cultured supernatants of hUMSCs and glycogen synthase kinase 3 beta (GSK3ß) inhibitor (SB216763) were used to treat theca cells (TCs) exposed to CTX. Hematoxylin and Eosin (H&E) staining and Enzyme-linked immunosorbent assay (ELISA) were used to assess ovarian structure and morphology, as well as endocrine function in these POI mice. Based on results from the ELISA and JC-1 labeling, CTX exerted significant detrimental effects on testosterone levels and the mitochondrial membrane potential in TCs. Subsequently, Western Blot, Immunofluorescence staining (IF), and Quantitative real-time polymerase chain reaction (qRT-PCR) were used to evaluate various indicators of testosterone synthesis function and mitochondrial dynamics in ovaries and TCs of POI mice. In vivo, dysfunctions in ovarian structure and function in the POI mouse model were effectively restored following hUMSCs treatment, and abnormalities in hormone synthesis were significantly reduced. Furthermore, when the stem cell supernatants of hUMSCs were applied to TCs in vitro we found that GSK3ß expression was reduced, the imbalance of mitochondrial dynamics was alleviated, and the ability of mitochondrial testosterone synthesis was increased. Taken together, our results indicate that hUMSCs treatment can restore the imbalance of mitochondrial dynamics and restart testosterone synthesis of TCs by suppressing GSK3ß expression, ultimately alleviating POI damage.

SFRP4 promotes autophagy and blunts FSH responsiveness through inhibition of AKT signaling in ovarian granulosa cells.

BACKGROUND: Secreted frizzled-related proteins (SFRPs) comprise a family of WNT signaling antagonists whose roles in the ovary are poorly understood. Sfrp4-null mice were previously found to be hyperfertile due to an enhanced granulosa cell response to gonadotropins, leading to decreased antral follicle atresia and enhanced ovulation rates. The present study aimed to elucidate the mechanisms whereby SFRP4 antagonizes FSH action. METHODS: Primary cultures of granulosa cells from wild-type mice were treated with FSH and/or SFRP4, and effects of treatment on gene expression were evaluated by RT-qPCR and RNAseq. Bioinformatic analyses were conducted to analyse the effects of SFRP4 on the transcriptome, and compare them to those of FSH or a constitutively active mutant of FOXO1. Additional granulosa cell cultures from wild-type or Sfrp4-null mice, some pretreated with pharmacologic inhibitors of specific signaling effectors, were used to examine the effects of FSH and/or SFRP4 on signaling pathways, autophagy and apoptosis by western blotting and TUNEL. RESULTS: Treatment of cultured granulosa cells with recombinant SFRP4 was found to decrease basal and FSH-stimulated mRNA levels of FSH target genes. Unexpectedly, this effect was found to occur neither via a canonical (CTNNB1-dependent) nor non-canonical WNT signaling mechanism, but was found to be GSK3ß-dependent. Rather, SFRP4 was found to antognize AKT activity via a mechanism involving AMPK. This lead to the hypophosphorylation of FOXO1 and a decrease in the expression of a portion of the FSH and FOXO1 transcriptomes. Conversely, FSH-stimulated AMPK, AKT and FOXO1 phosphorylation levels were found to be increased in the granulosa cells of Sfrp4-null mice relative to wild-type controls. SFRP4 treatement of granulosa cells also induced autophagy by signaling via AKT-mTORC1-ULK1, as well as apoptosis. CONCLUSIONS: This study identifies a novel GSK3ß-AMPK-AKT signaling mechanism through which SFPR4 antagonizes FSH action, and further identifies SFRP4 as a novel regulator of granulosa cell autophagy. These findings provide a mechanistic basis for the phenotypic changes previously observed in Sfrp4-null mice, and broaden our understanding of the physiological roles of WNT signaling processes in the ovary.

The C5AR1/TNFSF13B axis alleviates osteoarthritis by activating the PI3K/Akt/GSK3ß/Nrf2/HO-1 pathway to inhibit ferroptosis.

Chondrocyte ferroptosis induces the occurrence of osteoarthritis (OA). As a key gene of OA, C5a receptor 1 (C5AR1) is related to ferroptosis. Here, we investigated whether C5AR1 interferes with chondrocyte ferroptosis during OA occurrence. C5AR1 was downregulated in PA-treated chondrocytes. Overexpression of C5AR1 increased the cell viability and decreased ferroptosis in chondrocytes. Moreover, Tumor necrosis factor superfamily member 13B (TNFSF13B) was downregulated in PA-treated chondrocytes, and knockdown of TNFSF13B eliminated the inhibitory effect of C5AR1 on ferroptosis in chondrocytes. More importantly, the PI3K/Akt/GSK3ß/Nrf2/HO-1 pathway inhibitor LY294002 reversed the inhibition of C5AR1 or TNFSF13B on ferroptosis in chondrocytes. Finally, we found that C5AR1 alleviated joint tissue lesions and ferroptosis in rats and inhibited the progression of OA in the rat OA model constructed by anterior cruciate ligament transection (ACLT), which was reversed by interfering with TNFSF13B. This study shows that C5AR1 reduces the progression of OA by upregulating TNFSF13B to activate the PI3K/Akt/GSK3ß/Nrf2/HO-1 pathway and thereby inhibiting chondrocyte sensitivity to ferroptosis, indicating that C5AR1 may be a potential therapeutic target for ferroptosis-related diseases.

GSK3-Driven Modulation of Inflammation and Tissue Integrity in the Animal Model.

Nowadays, GSK3 is accepted as an enzyme strongly involved in the regulation of inflammation by balancing the pro- and anti-inflammatory responses of cells and organisms, thus influencing the initiation, progression, and resolution of inflammatory processes at multiple levels. Disturbances within its broad functional scope, either intrinsically or extrinsically induced, harbor the risk of profound disruptions to the regular course of the immune response, including the formation of severe inflammation-related diseases. Therefore, this review aims at summarizing and contextualizing the current knowledge derived from animal models to further shape our understanding of GSK3α and ß and their roles in the inflammatory process and the occurrence of tissue/organ damage. Following a short recapitulation of structure, function, and regulation of GSK3, we will focus on the lessons learned from GSK3α/ß knock-out and knock-in/overexpression models, both conventional and conditional, as well as a variety of (predominantly rodent) disease models reflecting defined pathologic conditions with a significant proportion of inflammation and inflammation-related tissue injury. In summary, the literature suggests that GSK3 acts as a crucial switch driving pro-inflammatory and destructive processes and thus contributes significantly to the pathogenesis of inflammation-associated diseases.

Irisin promotes hair growth and hair cycle transition by activating the GSK-3ß/ß-catenin pathway.

Hair loss affects men and women of all ages. Myokines, which are mainly secreted by skeletal muscles during exercise, have numerous health benefits. VEGF, IGF-1, FGF and irisin are reprehensive myokines. Although VEGF, IGF-1 and FGF are positively associated with hair growth, few studies have researched the effects of irisin on hair growth. Here, we investigated whether irisin promotes hair growth using in vitro, ex vivo and in vivo patch assays, as well as mouse models. We show that irisin increases proliferation, alkaline phosphatase (ALP) activity and mitochondrial membrane potential in human dermal papilla cells (hDPCs). Irisin activated the Wnt/ß-catenin signalling pathway, thereby upregulating Wnt5a, Wnt10b and LEF-1, which play an important role in hair growth. Moreover, irisin enhanced human hair shaft elongation. In vivo, patch assays revealed that irisin promotes the generation of new hair follicles, accelerates entry into the anagen phase, and significantly increases hair growth in C57BL/6 mice. However, XAV939, a Wnt/ß-catenin signalling inhibitor, suppressed the irisin-mediated increase in hair shaft and hair growth. These results indicate that irisin increases hair growth via the Wnt/ß-catenin pathway and highlight its therapeutic potential in hair loss treatment.

Examination of Akt and GSK3ß in BDNF-mediated reductions in BACE1 activity in neuronal cells.

Brain-derived neurotrophic factor (BDNF) content and signaling has been identified as one potential regulator of amyloid precursor protein (APP) processing. Recently published work has demonstrated that BDNF reduces BACE1 activity while also elevating the inhibition of GSK3ß in the prefrontal cortex of male C57BL/6J mice. These results provide evidence that BDNF alters APP processing by reducing BACE1 activity, which may act through GSK3ß inhibition. The purpose of this study was to further explore the role of GSK3ß in BDNF-induced regulation on BACE1 activity. We utilized a cell culture and an in vitro activity assay model to pharmacologically target BDNF and GSK3ß signaling to confirm its involvement in the BDNF response. Treatment of differentiated SH-SY5Y neuronal cells with 75 ng/mL BDNF resulted in elevated pTrkB content, pAkt content, pGSK3ß content, and reduced BACE1 activity. An in vitro BACE1 activity assay utilizing mouse prefrontal cortex (n = 6/group) supplemented with BDNF, BDNF + ANA12 (Trkb antagonist), or BDNF + wortmannin (Akt inhibitor) demonstrated that BDNF reduced BACE1 activity; however, in the presence of TrkB or Akt inhibition, this effect was abolished. An in vitro ADAM10 activity assay utilizing mouse prefrontal cortex (n = 6/group) supplemented with BDNF, BDNF + ANA12 (Trkb antagonist), or BDNF + wortmannin (Akt inhibitor) demonstrated that BDNF did not alter ADAM10 activity. However, inhibiting BDNF signaling reduced ADAM10 activity. Collectively these studies suggest that GSK3ß inhibition may be necessary for BDNF-induced reductions in BACE1 activity. These findings will allow for the optimization of future therapeutic strategies by selectively targeting TrkB activation and GSK3ß inhibition.

GSK3B inhibition reduced cervical cancer cell proliferation and migration by modulating the PI3K/Akt signaling pathway and epithelial-to-mesenchymal transition.

Previous studies show that glycogen synthase kinase 3ß (GSK3B) plays an important role in tumorigenesis. However, its role in cervical cancer is unclear. The present study silenced GSK3B with siRNAs and/or chemical inhibitors to determine its role in HeLa cervical cancer cell proliferation and migration as well as in xenograft tumor growth. Cell Counting Kit (CCK)-8 and 5-ethynyl-2'-deoxyuridine (EdU) assays were used to determine cell survival and proliferation. Scratch and Transwell® assays were used to evaluate cell migration. Xenograft tumors were used to evaluate the effect of GSK3B on tumor growth. Transcriptomic sequencing was used to clarify the mechanisms underlying the foregoing processes. Public databases and clinical specimens showed that GSK3B was upregulated in cervical cancer tissues and correlated with poor prognosis. In vitro experiments indicated that GSK3B inhibition reduced cell viability, proliferation, and migration. In vivo experiments demonstrated that GSK3B inhibition slowed xenograft tumor growth. Transcriptomic sequencing revealed that GSK3B inhibition modulated the phosphatidylinositol 3-carboxykinase (PI3K)/protein kinase B (Akt) and extracellular matrix (ECM)-receptor interaction signaling pathways. GSK3B inhibition decreased the protein levels of phosphorylated PI3K and Akt and the levels of mesenchymal markers but increased those of epithelial markers. An activator of the PI3K/Akt signaling pathway counteracted the suppressive effects of GSK3B inhibition on HeLa cell viability and proliferation and on PI3K/Akt signaling. Our data suggested that GSK3B regulated cervical cancer cell proliferation and migration by modulating the PI3K/Akt signaling pathway and epithelial-to-mesenchymal transition (EMT).

Exploring Novel GSK-3ß Inhibitors for Anti-Neuroinflammatory and Neuroprotective Effects: Synthesis, Crystallography, Computational Analysis, and Biological Evaluation.

In the pathogenesis of Alzheimer's disease, the overexpression of glycogen synthase kinase-3ß (GSK-3ß) stands out due to its multifaced nature, as it contributes to the promotion of amyloid ß and tau protein accumulation, as well as neuroinflammatory processes. Therefore, in the present study, we have designed, synthesized, and evaluated a new series of GSK-3ß inhibitors based on the N-(pyridin-2-yl)cyclopropanecarboxamide scaffold. We identified compound 36, demonstrating an IC50 of 70 nM against GSK-3ß. Subsequently, through crystallography studies and quantum mechanical analysis, we elucidated its binding mode and identified the structural features crucial for interactions with the active site of GSK-3ß, thereby understanding its inhibitory potency. Compound 36 was effective in the cellular model of hyperphosphorylated tau-induced neurodegeneration, where it restored cell viability after okadaic acid treatment and showed anti-inflammatory activity in the LPS model, significantly reducing NO, IL-6, and TNF-α release. In ADME-tox in vitro studies, we confirmed the beneficial profile of 36, including high permeability in PAMPA (Pe equals 9.4) and high metabolic stability in HLMs as well as lack of significant interactions with isoforms of the CYP enzymes and lack of considerable cytotoxicity on selected cell lines (IC50 > 100 µM on HT-22 cells and 89.3 µM on BV-2 cells). Based on promising pharmacological activities and favorable ADME-tox properties, compound 36 may be considered a promising candidate for in vivo research as well as constitute a reliable starting point for further studies.

Altered lipid metabolism promoting cardiac fibrosis is mediated by CD34+ cell-derived FABP4+ fibroblasts.

Hyperlipidemia and hypertension might play a role in cardiac fibrosis, in which a heterogeneous population of fibroblasts seems important. However, it is unknown whether CD34+ progenitor cells are involved in the pathogenesis of heart fibrosis. This study aimed to explore the mechanism of CD34+ cell differentiation in cardiac fibrosis during hyperlipidemia. Through the analysis of transcriptomes from 50,870 single cells extracted from mouse hearts and 76,851 single cells from human hearts, we have effectively demonstrated the evolving cellular landscape throughout cardiac fibrosis. Disturbances in lipid metabolism can accelerate the development of fibrosis. Through the integration of bone marrow transplantation models and lineage tracing, our study showed that hyperlipidemia can expedite the differentiation of non-bone marrow-derived CD34+ cells into fibroblasts, particularly FABP4+ fibroblasts, in response to angiotensin II. Interestingly, the partial depletion of CD34+ cells led to a notable reduction in triglycerides in the heart, mitigated fibrosis, and improved cardiac function. Furthermore, immunostaining of human heart tissue revealed colocalization of CD34+ cells and fibroblasts. Mechanistically, our investigation of single-cell RNA sequencing data through pseudotime analysis combined with in vitro cellular studies revealed the crucial role of the PPARγ/Akt/Gsk3ß pathway in orchestrating the differentiation of CD34+ cells into FABP4+ fibroblasts. Through our study, we generated valuable insights into the cellular landscape of CD34+ cell-derived cells in the hypertrophic heart with hyperlipidemia, indicating that the differentiation of non-bone marrow-derived CD34+ cells into FABP4+ fibroblasts during this process accelerates lipid accumulation and promotes heart failure via the PPARγ/Akt/Gsk3ß pathway.

Inhibition of Calcineurin with FK506 Reduces Tau Levels and Attenuates Synaptic Impairment Driven by Tau Oligomers in the Hippocampus of Male Mouse Models.

Alzheimer's disease (AD) is the most common age-associated neurodegenerative disorder, characterized by progressive cognitive decline, memory impairment, and structural brain changes, primarily involving Aß plaques and neurofibrillary tangles of hyperphosphorylated tau protein. Recent research highlights the significance of smaller Aß and Tau oligomeric aggregates (AßO and TauO, respectively) in synaptic dysfunction and disease progression. Calcineurin (CaN), a key calcium/calmodulin-dependent player in regulating synaptic function in the central nervous system (CNS) is implicated in mediating detrimental effects of AßO on synapses and memory function in AD. This study aims to investigate the specific impact of CaN on both exogenous and endogenous TauO through the acute and chronic inhibition of CaN. We previously demonstrated the protective effect against AD of the immunosuppressant CaN inhibitor, FK506, but its influence on TauO remains unclear. In this study, we explored the short-term effects of acute CaN inhibition on TauO phosphorylation and TauO-induced memory deficits and synaptic dysfunction. Mice received FK506 post-TauO intracerebroventricular injection and TauO levels and phosphorylation were assessed, examining their impact on CaN and GSK-3ß. The study investigated FK506 preventive/reversal effects on TauO-induced clustering of CaN and GSK-3ß. Memory and synaptic function in TauO-injected mice were evaluated with/without FK506. Chronic FK506 treatment in 3xTgAD mice explored its influence on CaN, Aß, and Tau levels. This study underscores the significant influence of CaN inhibition on TauO and associated AD pathology, suggesting therapeutic potential in targeting CaN for addressing various aspects of AD onset and progression. These findings provide valuable insights for potential interventions in AD, emphasizing the need for further exploration of CaN-targeted strategies.

DNA Methylation in Recurrent Glioblastomas: Increased TEM8 Expression Activates the Src/PI3K/AKT/GSK-3ß/B-Catenin Pathway.

BACKGROUND/AIM: Glioblastomas (GBM) are infiltrative malignant brain tumors which mostly recur within a year's time following surgical resection and chemo-radiation therapy. Studies on glioblastoma cells following radio-chemotherapy, have been demonstrated to induce trans-differentiation, cellular plasticity, activation of DNA damage response and stemness. As glioblastomas are heterogenous tumors that develop treatment resistance and plasticity, we investigated if there exist genome-wide DNA methylation changes in recurrent tumors. MATERIALS AND METHODS: Utilizing genome-wide DNA methylation arrays, we compared the DNA methylation profile of 11 primary (first occurrence) tumors with 13 recurrent (relapsed) GBM, to delineate the contribution of epigenetic changes associated with therapy exposure, therapy resistance, and relapse of disease. RESULTS: Our data revealed 1,224 hypermethylated- and 526 hypomethylated-probes in recurrent glioblastomas compared to primary disease. We found differential methylation of solute carrier and ion channel genes, interleukin receptor/ligand genes, tumor-suppressor genes and genes associated with metastasis. We functionally characterized one such hypomethylated-up-regulated gene, namely anthrax toxin receptor 1/tumor endothelial marker 8 (ANTXR1/TEM8), whose expression was validated to be significantly up-regulated in recurrent glioblastomas compared to primary tumors and confirmed by immunohistochemistry. Using overexpression and knockdown approaches, we showed that TEM8 induces proliferation, invasion, migration, and chemo-radioresistance in glioblastoma cells. Additionally, we demonstrated a novel mechanism of ß-catenin stabilization and activation of the ß-catenin transcriptional program due to TEM8 overexpression via a Src/PI3K/AKT/GSK3ß/ß-catenin pathway. CONCLUSION: We report genome-wide DNA methylation changes in recurrent GBM and suggest involvement of the TEM8 gene in GBM recurrence and progression.

Opposite regulation by L-DOPA receptor GPR143 of the long and short forms of the dopamine D2 receptors.

Dopamine (DA) D2 receptors (D2Rs) have 2 isoforms, a long form (D2L) and a short form (D2S). D2L is predominantly postsynaptic in the striatal medium spiny neurons and cholinergic interneurons. D2S is principally presynaptic autoreceptors in the nigrostriatal DA neurons. Recently, we demonstrated that L-3,4-dihydroxyphenylalanine (L-DOPA) augments D2L function through the coupling between D2L and GPR143, a receptor of L-DOPA that was originally identified as the gene product of ocular albinism 1. Here we show that GPR143 modifies the functions of D2L and D2S in an opposite manner. Haloperidol-induced catalepsy was attenuated in DA neuron-specific Gpr143 gene-deficient (Dat-cre;Gpr143flox/y) mice, compared with wild-type (Wt) mice. Haloperidol increased in vivo DA release from the dorsolateral striatum, and this increase was augmented in Gpr143-/y mice compared with Wt mice. A D2R agonist quinpirole-induced increase in the phosphorylation of GSK3ß(pGSK3ß(S9)) was enhanced in Chinese hamster ovary (CHO) cells coexpressing D2L and GPR143 compared with cells expressing D2L alone, while it was suppressed in cells coexpressing D2S and GPR143 compared with D2S alone, suggesting that GPR143 differentially modifies D2R functions depending on its isoforms of D2L and D2S.