Intracellular Accumulation Research Articles

Metformin suppresses metabolic dysfunction-associated fatty liver disease by ferroptosis and apoptosis via activation of oxidative stress

Metformin is known for its antioxidant properties and ability to ameliorate metabolic dysfunction-associated fatty liver disease (MAFLD) and is the focus of this study. Lipoprotein-associated phospholipase A2 (Lp-PLA2) is linked to MAFLD risk. This study investigated the effects of metformin on ferroptosis in free fatty acid (FFA)-treated Huh7 hepatoma cells and its association with MAFLD risk. Using Western blot, immunofluorescence, and ELISA, this study revealed that FFA treatment led to increased intracellular fat and iron accumulation, heightened Lp-PLA2 expression, reduced levels of the cysteine transporter SLC7A11 and glutathione peroxidase 4 (GPX4), altered glutathione (GSH)/oxidized glutathione (GSSG) ratios, generation of reactive oxygen species (ROS), and initiation of lipid peroxidation, which ultimately resulted in cell ferroptosis. Importantly, metformin reversed FFA-induced iron accumulation, and this effect was attenuated by ferrostatin-1 but enhanced by erastin, RSL3, and si-GPX4. Additionally, metformin activated antioxidant and antiapoptotic mechanisms, which reduced lipid peroxidation and suppressed Lp-PLA2 expression in FFA-treated Huh7 cells. In conclusion, our findings indicate that metformin may protect against MAFLD by inhibiting iron accumulation and Lp-PLA2 expression through the ROS, ferroptosis, and apoptosis signaling pathways. This study highlights potential therapeutic strategies for managing MAFLD-related risks and emphasizes the diverse roles of metformin in maintaining hepatocyte balance.

The signal peptide of BmNPV GP64 activates the ERAD pathway to regulate heterogeneous secretory protein expression

As a powerful eukaryotic expression vector, the baculovirus expression vector system (BEVS) is widely applied to the production of heterogeneous proteins for research and pharmaceutical purposes, while optimization of BEVS remains a work in progress for membrane or secreted protein expression. In this study, the impact of the signal peptide (SP) derived from Bombyx mori nucleopolyhedrovirus (BmNPV) GP64 protein on protein expression, secretion, and the endoplasmic reticulum-associated degradation (ERAD) pathway were investigated in BmN cells and BEVS. Transient expression studies in BmN cells revealed that SP alters the localization and expression levels of recombinant proteins, reducing intracellular accumulation while enhancing secretion efficiency. Quantitative analysis demonstrated that SP-mediated secretion was markedly higher compared to controls, albeit with lower total expression levels. Further exploration into SP-mediated ERAD pathway activation showed increased expression of BiP and other ERAD-associated genes (PDI, UFD1, S1P, and ASK1), correlating with higher SP-driven protein expression levels. RNA interference (RNAi) experiments elucidated that knockdown of ERAD-associated genes enhances both the secretion efficiency of SP-guided proteins and the infectivity of BmNPV. Particularly, interference with BiP demonstrated the most pronounced effect on protein secretion enhancement. Viral infection experiments further supported these findings, showing upregulated ERAD-associated genes during BmNPV infection, indicating their role in viral protein processing and infectivity. In conclusion, this study elucidates the complex interplay between SP-mediated protein secretion, ERAD pathway activation, and viral infectivity in BmNPV-infected cells. These insights suggest strategies for optimizing recombinant protein production and viral protein processing in baculovirus expression systems, with potential implications for biotechnological and biomedical applications. Further research could refine our understanding and manipulation of protein secretion pathways in insect cell-based expression systems.

Molecular mechanism of ectopic lipid accumulation induced by methylglyoxal via activation of the NRF2/PI3K/AKT pathway implicates renal lipotoxicity caused by diabetes mellitus.

Patients with chronic kidney disease (CKD) have a high incidence of dyslipidemia comprising high triglyceride (TG) and low high-density lipoprotein (HDL)-cholesterol levels. An abnormal increase of TGs within cells can lead to intracellular lipid accumulation. In addition to dyslipidemia, hyperglycemia in diabetes may elicit ectopic lipid deposition in non-adipose tissues. Hyperglycemia increases intracellular levels of methylglyoxal (MG) leading to cellular dysfunction. A deficit of glyoxalase I (GLO1) contributes to dicarbonyl stress. Whether dicarbonyl stress induced by MG causes renal lipotoxicity through alteration of lipid metabolism signaling is still unknown. In this study, mice with high fat diet-induced diabetes were used to investigate the renal pathology induced by MG. NRK52E cells treated with MG were further used in vitro to delineate the involvement of lipogenic signaling. After treatment with MG for 12 weeks, plasma TG levels, renal fatty changes, and tubular injuries were aggravated in diabetic mice. In NRK52E cells, MG activated the nuclear factor erythroid 2-related factor 2 (Nrf2)/phosphatidylinositol 3-kinase (PI3K)/protein kinase B (AKT) and sterol regulatory element-binding protein 1 (SREBP1), resulting in stimulation of fatty acid synthase. The intracellular accumulation of lipid droplets was mainly contributed by TGs, which increased the oxidative stress accompanied by high Nrf2 expression. In addition, MG time-dependently activated cyclin D, cyclin-dependent kinase 4 (CDK4), and cleaved caspase-3, evidencing that G0/G1 arrest was associated with apoptosis of NRK52E cells. In conclusion, our studies revealed the mechanism of lipotoxicity caused by MG. The target of such dicarbonyl stress may become a promising therapy for diabetic CKD.

Effects of inorganic phosphate on stem cells isolated from human exfoliated deciduous teeth

Calcium phosphate-based materials (CaP) are introduced as potential dental pulp capping materials for deciduous teeth. The present study investigated the influence of inorganic phosphate (Pi) on regulating stem cells isolated from human exfoliated deciduous teeth (SHED). SHEDs were treated with Pi. Cell cycle progression and apoptosis were examined using flow cytometry analysis. Osteo/odontogenic and adipogenic differentiation were analyzed using alizarin red S and oil red O staining, respectively. The mRNA expression profile was investigated using a high-throughput RNA sequencing technique. Pi increased the late apoptotic cell population while cell cycle progression was not altered. Pi upregulated osteo/odontoblastic gene expression and enhanced calcium deposition. Pi-induced mineralization was reversed by pretreatment of cells with Foscarnet, or p38 inhibitor. Pi treatment inhibited adipogenic differentiation as determined by decreased PPARγ expression and reduced intracellular lipid accumulation. Bioinformatic analysis of gene expression profiles demonstrated several involved pathways, including PI3K/AKT, MAPK, EGFR, and VEGF signaling. In conclusion, Pi enhanced osteo/odontogenic but inhibited adipogenic differentiation in SHED.

APX2009 sensitizes hypoxic breast cancer cells to doxorubicin by increasing its accumulation and caspase-3/7-mediated apoptosis.

The association of targeted therapy with chemotherapy is encouraged to increase the treatment efficiency, especially in hypoxic triple-negative breast cancer. The APE1 redox activity has stood out as a potential tumor target. However, the effect of the association of the APE1 redox inhibitors with doxorubicin in hypoxia still needs to be evidenced. Therefore, our objective was to investigate the effect of the APX2009 (APE1 inhibitor) on the sensitization of breast cancer cells to doxorubicin in normoxia and hypoxia. The WST-1 assay was used to evaluate cell viability after APX2009 and doxorubicin application under normoxia and hypoxia conditions in the MCF-7 and MDA-MB-231 cells. Apoptosis was analyzed by annexin assay and detection of caspases-3/7 activity by luminescence-based assay. The clinical association between APE1 inhibition signature and doxorubicin sensitivity was evaluated by bioinformatics analyses. MDA-MB-231 and MCF-7 cell lines were more sensitive to APX2009 in normoxia than in hypoxia. Co-treatment with APX2009 and doxorubicin in hypoxia further decreased the viability of triple-negative MDA-MB-231 cells than treatment alone, which was accompanied by doxorubicin intracellular accumulation, and increase of apoptotic cells percentage, and caspases-3/7 activity. Moderate association was found between APE1 inhibition signature and doxorubicin sensitivity in the hypoxic basal subtype. The findings suggest that APX2009 sensitizes the MDA-MB-231 cells to doxorubicin in hypoxia by doxorubicin intracellular accumulation and caspases-3/7-mediated apoptosis.

Anti-Obesity Effect of Fresh and Browned Magnolia denudata Flowers in 3T3-L1 Adipocytes

The major components of magnolia flower extracts (MFEs) were classified into four substances, such as flavonoids, phenylethanoid glycoside derivatives (PhGs), caffeoylquinic acids (CQAs), and others, in our previous study. The chemical components of MFEs, including the rutin of flavonoid, acteoside and isoacteoside of PhGs, and caffeyolquinic acids, are reported to have physiological effects on anti-obesity effects. The anti-obesity effect of fresh and browned Magnolia denudata flower extracts (FMFE and BMFE, respectively) was investigated in 3T3-L1 adipocytes. The treatment concentrations of FMFE and BMFE were 200 and 400 μg/mL, respectively, as determined with the WST-1 assay. Intracellular lipid accumulation in 3T3-L1 cells was inhibited with the treatment of MFEs, including FMFE and BMFE, as observed with an image of the culture plate, using an optical microscope and Oil red O staining. The expression of the adipogenic target genes involved in adipocyte differentiation, including PPARγ, C/EBPα, perilipin, FABP4, FAS, HSL, and SREBP-1, was suppressed with the treatment of MFEs. Additionally, the phosphorylation of AMPK and ACC in 3T3-L1 cells was significantly increased following treatment with the MFEs. These results suggest that both MFEs have a potential for physiological effects on anti-obesity activity.

Blue Mussel-Derived Bioactive Peptides PIISVYWK (P1) and FSVVPSPK (P2): Promising Agents for Inhibiting Foam Cell Formation and Inflammation in Cardiovascular Diseases.

Atherosclerosis is a key etiological event in the development of cardiovascular diseases (CVDs), strongly linked to the formation of foam cells. This study explored the effects of two blue mussel-derived bioactive peptides (BAPs), PIISVYWK (P1) and FSVVPSPK (P2), on inhibiting foam cell formation and mitigating inflammation in oxLDL-treated RAW264.7 macrophages. Both peptides significantly suppressed intracellular lipid accumulation and cholesterol levels while promoting cholesterol efflux by downregulating cluster of differentiation 36 (CD36) and class A1 scavenger receptors (SR-A1) and upregulating ATP binding cassette subfamily A member 1 (ABCA-1) and ATP binding cassette subfamily G member 1 (ABCG-1) expressions. The increased expression of peroxisome proliferator-activated receptor-gamma (PPAR-γ) and liver X receptor-alpha (LXR-α) further validated their role in enhancing cholesterol efflux. Additionally, P1 and P2 inhibited foam cell formation in oxLDL-treated human aortic smooth muscle cells and exerted anti-inflammatory effects by reducing pro-inflammatory cytokines, nitric oxide (NO), prostaglandin E2 (PGE2), inducible nitric oxide synthase (iNOS), and cyclooxygenase-2 (COX-2), primarily through inhibiting NF-κB activation. Furthermore, P1 and P2 alleviated oxidative stress by activating the Nrf2/HO-1 pathway. Our findings demonstrate that P1 and P2 have significant potential in reducing foam cell formation and inflammation, both critical factors in atherosclerosis development. These peptides may serve as promising therapeutic agents for the prevention and treatment of CVDs associated with oxidative stress and inflammation.

Epertinib counteracts multidrug resistance in cancer cells by antagonizing the drug efflux function of ABCB1 and ABCG2

A significant hurdle in cancer treatment arises from multidrug resistance (MDR), often due to overexpression of ATP-binding cassette (ABC) transporters like ABCB1 and/or ABCG2 in cancer cells. These transporters actively diminish the efficacy of cytotoxic drugs by facilitating ATP hydrolysis-dependent drug efflux and reducing intracellular drug accumulation in cancer cells. Addressing multidrug-resistant cancers poses a significant challenge due to the lack of approved treatments, prompting the exploration of alternative avenues like drug repurposing (also referred to as drug repositioning) of molecularly targeted agents to reverse MDR-mediated by ABCB1 and/or ABCG2 in multidrug-resistant cancer cells. Epertinib, a potent inhibitor of EGFR and HER2 currently in clinical trials for solid tumors, was investigated for its potential to resensitize ABCB1- and ABCG2-overexpressing multidrug-resistant cancer cells to chemotherapeutic agents. Our findings reveal that at sub-toxic, submicromolar concentrations, epertinib restores the sensitivity of multidrug-resistant cancer cells to cytotoxic drugs in a concentration-dependent manner. The results demonstrate that epertinib enhances drug-induced apoptosis in these cancer cells by impeding the drug-efflux function of ABCB1 and ABCG2 without altering their expression. ATPase activity and molecular docking were employed to reveal potential interaction sites between epertinib and the drug-binding pockets of ABCB1 and ABCG2. In summary, our study demonstrates an additional pharmacological capability of epertinib against the activity of ABCB1 and ABCG2. These findings suggest that incorporating epertinib into combination therapy could be advantageous for a specific patient subset with tumors exhibiting high levels of ABCB1 or ABCG2, warranting further exploration.

Purple Butter Clam (Saxidomus Purpurata) as a Potential Functional Food Source for Obesity Treatment.

Saxidomus purpurata extract (SPE) is a highly consumable seafood worldwide with known health-related benefits. However, there are no reports of its' anti-obesity effect. This study explores the potential of SPE for anti-obesity effects by modulating adipogenesis and lipolysis. SPE reduced intracellular lipid and triglyceride accumulation while increasing free glycerol release in adipocytes. SPE inhibited lipogenesis protein expressions and increased the phosphorylation of hormone-sensitive lipase and Adenosine monophosphate-activated protein kinase (AMPK) to promote lipolysis. In addition, SPE suppressed adipogenesis by downregulating protein expression of key adipogenic markers, peroxisome proliferator-activated receptor gamma (PPARγ), CCAAT/enhancer-binding protein α (C/EBPα), and sterol regulatory element-binding protein 1 (SREBP1) via Wnt/β-catenin signaling. SPE augmented the heme oxygenase-1 (HO-1) expression. Thus, pharmacological intervention with Zinc protoporphyrin (ZnPP-HO-1 antagonist) was employed to validate the HO-1 role. The presence of ZnPP increased the lipid accumulation and reduced the free glycerol release. At the molecular level, adipogenic transcription factors (PPARγ, C/EBPα, and SREBP1) expressions were restored in the presence of ZnPP. GC-MS analysis revealed that SPE was comprised of several fatty acids, contributing to its anti-obesity activity. SPE is an effective nutraceutical that can be used to reduce the progression of obesity. HO-1 expression during adipogenesis might be the mechanism of action for the anti-obesity effect of SPE.

Engineering the by-products pathway in Aureobasidium pullulans for highly purified polymalic acid fermentation with concurrent recovery of l-malic acid

The fermentation of polymalic acid (PMA) by Aureobasidium pullulans, followed by acid hydrolysis to release the monomer l-malic acid (l-MA), has emerged as a promising process for the bio-based production of l-MA. However, the presence of specific by-products significantly affects the quality of the final products. In this study, chassis strains harboring an overexpressed endogenous malate dehydrogenase gene (ApMDH2) were engineered to delete key genes involved in the pullulan, melanin, and liamocin biosynthetic pathways. Furthermore, to enhance PMA synthesis productivity and prevent intracellular NADPH accumulation, an irreversible trans-hydrogenase transformation system was designed to efficiently convert NADPH to NADH. In fed-batch fermentation, the engineered strain produced the highest PMA titer (194.3 ± 1.1 g/L) and l-MA yield (0.89 ± 0.01 g/g) with an increased productivity (1.45 ± 0.06 g/L∙h). Moreover, a total of 86.19 % l-MA, with a purity of 99.7 %, was successfully extracted from fermentation broth.

JNK inhibitor and ferroptosis modulator as possible therapeutic modalities in Alzheimer disease (AD)

Alzheimer disease (AD) is among the most prevalent neurodegenerative diseases globally, marked by cognitive and behavioral disruptions. Ferroptosis is a form of controlled cell death characterized by intracellular iron accumulation associated with lipid peroxide formation, which subsequently promotes AD initiation and progression. We hypothesized that targeting the ferroptosis pathway may help in AD management. Therefore, our study aimed to evaluate the potential neuroprotective effect of the antifungal Ciclopirox olamine (CPX-O) that acts through iron chelation. We employed CPX-O separately or in combination with the JNK inhibitor (SP600125) in a mice model of AlCl3-induced AD. Animals underwent examination for behavioral, biochemical, histological, and immunohistochemical findings. Our results revealed that AlCl3 was associated with disruptions in learning and memory parameters, neuronal degeneration in the hippocampus, increased immunoreactivity of amyloid-β and tau proteins, a significant rise in iron, nitric oxide (NO), malondialdehyde (MDA), JNK, and P53 levels, along with the significant decrease in glutathione peroxidase activity. Interestingly, the administration of CPX-O alone or in combination with SP600125 in the AlCl3-induced AD model caused an improvement in the previously described examination findings. Therefore, CPX-O may be a promising candidate for AD treatment, and future clinical trials will be required to confirm these preclinical findings.

Combined blockade of GPX4 and activated EGFR/HER3 bypass pathways inhibits the development of ALK-inhibitor-induced tolerant persister cells in ALK-fusion-positive lung cancer.

Cancers can develop resistance to treatment with ALK tyrosine kinase inhibitors (ALK-TKIs) via emergence of a subpopulation of drug-tolerant persister (DTP) cells that can survive initial drug treatment long enough to acquire genetic aberrations. DTP cells are thus a potential therapeutic target. We generated alectinib-induced DTP cells from a patient-derived ALK+ non-small-cell lung cancer (NSCLC) cell line and screened 3114 agents in the anticancer compounds library (TargetMol). We identified phospholipid hydroperoxide glutathione peroxidase GPX4 as being involved in promoting the survival of DTP cells. GPX4 was found to be upregulated in DTP cells and to promote cell survival by suppressing reactive oxygen species (ROS) accumulation; GPX4 inhibitors blocked this upregulation and facilitated ROS-mediated cell death. Activated bypass signals involving epidermal growth factor receptor (EGFR)/receptor tyrosine-protein kinase erbB-3 (HER3) were also identified in DTP cells, and co-treatment with EGFR-TKI plus ALK-TKI enhanced ROS levels. Triple combination with an ALK-TKI plus a bypass pathway inhibitor plus a GPX4 inhibitor suppressed cell growth and induced intracellular ROS accumulation more greatly than did treatment with each agent alone. The combined inhibition of ALK plus inhibition of activated bypass signals plus inhibition of GPX4 may be a potent therapeutic strategy for patients with ALK+ NSCLC to prevent the development of resistance to ALK-TKIs and lead to tumor eradication.

Synthesis of Carborane–Thiazole Conjugates as Tyrosinase and 11β-Hydroxysteroid Dehydrogenase Inhibitors: Antiproliferative Activity and Molecular Docking Studies

The presented study depicts the synthesis of 11 carborane–thiazole conjugates with anticancer activity, as well as an evaluation of their biological activity as inhibitors of two enzymes: tyrosinase and 11β-hydroxysteroid dehydrogenase type 1 (11β-HSD1). The overexpression of tyrosinase results in the intracellular accumulation of melanin and can be observed in melanoma. The overexpression of 11β-HSD1 results in an elevation of glucocorticoid levels and has been associated with the aggravation of metabolic disorders such as type II diabetes mellitus and obesity. Recently, as the comorbidity of melanomas and metabolic disorders is being recognized as an important issue, the search for new therapeutic options has intensified. This study demonstrates that carborane–thiazole derivatives inhibit both enzymes, exerting beneficial effects. The antiproliferative action of all newly synthesized compounds was evaluated using three cancer cell lines, namely A172 (human brain glioblastoma), B16F10 (murine melanoma) and MDA-MB-231 (human breast adenocarcinoma), as well as a healthy control cell line of HUVEC (human umbilical vein endothelial cells). The results show that 9 out of 11 newly synthesized compounds demonstrated similar antiproliferative action against the B16F10 cell line to the reference drug, and three of these compounds surpassed it. To the best of our knowledge, this study is the first to demonstrate dual inhibitory action of carborane–thiazole derivatives against both tyrosinase and 11β-HSD1. Therefore, it represents the first step towards the simultaneous treatment of melanoma and comorbid diseases such as type II diabetes mellitus.

9316 Modulation Of Intracellular Lipid Access By ATGL Determines Ferroptosis Sensitivity In Castration-resistant Prostate Cancer

Abstract Disclosure: P. Cao: None. D. Awad: None. J. Han: None. D.E. Frigo: Grant Recipient; Self; GTx, Inc.. Other; Self; Familial relationship with Biocity Biopharmaceuticals, Hummingbird Bioscience, Bellicum Pharmaceuticals, Maia Biotechnology, Alms Therapeutics, Hinova Pharmaceuticals and Barricade Therapeutics. Ferroptosis induction has recently been recognized as a novel therapeutic approach to alter the outcomes of drug-resistant cancer. Ferroptosis is cell death that is caused by the intracellular accumulation of toxic lipid hydroperoxides. Due to their elevated metabolism, castration-resistant prostate cancer (CRPCs) are highly prone to ferroptosis; yet, many of them manage to avert this cellular fate. We have identified a key enzyme involved in lipid metabolism, adipose triglyceride lipase (ATGL), that engenders CRPCs with the ability to resist ferroptosis. Our data has shown that ATGL deletion by CRISPR-Cas9 knockout method sensitized human CRPC cell lines such as C4-2, C4-2BLT, and PC3 cells to the ferroptosis inducer RSL3. In all cases, RSL3-mediated cell death could be blocked by the antioxidant Ferrostatin-1, confirming ferroptosis as the mechanism of cell death. Knocking out ATGL also augmented the ferroptosis inducer-mediated increase in lipid peroxides as indicated by the increased ratio of oxidized to non-oxidized C11-BODIPY 581/591. With regards to the mechanism for the sensitivity of ATGL KO to ferroptosis induction, previous research has established that the enzyme long-chain acyl-CoA synthetase 4 (ACSL4) is universally essential to facilitate ferroptosis. More specifically, ATGL(PNPLA2) was found to inversely correlate with ACSL4 in the Taylor et al., the TCGA PanCancer Atlas, and Metastatic Prostate Adenocarcinoma (SU2C/PCF Dream Team) datasets in both primary and metastatic tumors. qPCR and western blot analysis of ACSL4 levels further showed that ACSL4 expression is closely tied to the lipase activity of ATGL. Addition of arachidonic acid significantly induced ferroptosis when combined with RSL3 in a dose-dependent manner only in ATGL KO cells. This indicates that PUFAs can render ATGL KO cells even more sensitive to RSL3-induced ferroptosis while cells with functional ATGL remain highly resistant, further reinforcing that ATGL is an essential safeguard of CRPC against ferroptosis. ATGL KO cells also demonstrated sensitivity to the antiandrogen Enzalutamide. The combination of Enzalutamide and RSL3 substantially decreased cell viability in ATGL KO cells as compared to control cells, indicating a strong synergy effect particularly seen in ATGL KO cells. In summary, this work demonstrates that ATGL is an important and novel regulator of ferroptosis in CRPC and supports the use of ferroptosis inducer as a new therapeutic approach in CRPC. Presentation: 6/2/2024

Design, Synthesis, and Biological Evaluation of New Improved Ferrostatin-1 Derived Ferroptosis Inhibitors.

Ferrostatin-1 (Fer-1), a first potent ferroptosis inhibitor, faces limitations in clinical use due to its low potency and metabolic instability. This study introduces a series of novel Ferrostatin-1 analogs designed to enhance plasm stability. Our design strategy focused on the modification of the 3-NH2 of Fer-1 with benzenesulfonyl groups, resulting in analogs 9-25. Biological evaluation revealed that compound 18, with an EC50 value of 0.57 µM, outperformed Fer-1 in inhibiting ferroptosis. It reduced intracellular ferrous ion accumulation, lipid peroxidation, and restored glutathione (GSH) and glutathione peroxidase 4 (GPX4) levels effectively. Moreover, compound 18 exhibited favorable solubility and remarkable metabolic stability in rat plasma. These results position compound 18 as a promising candidate for developing therapeutics against ferroptosis-related diseases.

Small Molecules Inducing Autophagic Degradation of Expanded Polyglutamine Protein through Interaction with Both Mutant ATXN3 and LC3.

Polyglutamine (polyQ)-mediated spinocerebellar ataxia (SCA), including SCA1, 2, 3, 6, 7, and 17, are caused by mutant genes with expanded CAG repeats, leading to the intracellular accumulation of aggregated proteins, the production of reactive oxygen species, and cell death. Among SCA, SCA3 is caused by a mutation in the ATXN3 (ataxin-3) gene. In a circumstance of polyQ aggregation, the autophagic pathway is induced to degrade the aggregated proteins, thereby suppressing downstream deleterious effects and promoting neuronal survival. In this study, we tested the effects of synthetic indole (NC009-1, -2, -3, -6) and coumarin (LM-022, -031) derivatives as chemical chaperones to assist mutant ATXN3-Q75 folding, as well as autophagy inducers to clear aggregated protein. Among the tested compounds, NC009-1, -2, and -6 and LM-031 interfered with Escherichia coli-derived ATXN3-Q75 aggregation in thioflavin T binding and filter trap assays. In SH-SY5Y cells expressing GFP-fused ATXN3-Q75, these compounds displayed aggregation-inhibitory and neurite growth-promoting potentials compared to untreated cells. Furthermore, these compounds activated autophagy by increasing the phosphatidylethanolamine-conjugated LC3 (microtubule associated protein 1 light chain 3)-II:cytosolic LC3-I ratio in these cells. A biochemical co-immunoprecipitation assay by using a mixture of HEK 293T cell lysates containing recombinant ATXN3-Q75-Venus-C-terminus (VC) or Venus-N-terminus (VN)-LC3 protein indicated that NC009-1 and -2 and LM-031 served as an autophagosome-tethering compound (ATTEC) to interact with ATXN3-Q75 and LC3, and the interaction was further confirmed by bimolecular fluorescence complementation analysis in cells co-expressing both ATXN3-Q75-VC and VN-LC3 proteins. The study results suggest the potential of NC009-1 and -2 and LM-031 as an ATTEC in treating SCA3 and, probably, other polyQ diseases.

Intracellular Methylglyoxal Accumulation in Classically Activated Mouse Macrophages is Mediated by HIF-1α.

Approximately one million cases of sepsis in the U.S.A. occur annually. The early phase of sepsis features dramatic changes in host metabolism and inflammation. While examining the effects of metabolic pathways on inflammation, we discovered that the highly reactive glycolytic metabolite, methylglyoxal (MG), accumulates intracellularly during classical activation of macrophages. Herein, we explored the role of glycolysis and the master regulator of glycolysis, Hypoxia-Inducing Factor-1α (HIF-1α), in inflammation and MG accumulation in mouse and human macrophages. To determine how HIF-1α regulates the inflammatory response of macrophages, we correlated HIF-1α stabilization with proinflammatory gene expression and MG-adduct accumulation in WT vs HIF1a-deficient macrophages treated with LPS or LPS+IFN-γ. A nearly complete loss of HIF-1α protein expression in response to the hypoxia mimetic, cobalt chloride, confirmed the phenotype of the HIF1a-deficient macrophages. Moreover, absence of HIF-1α was also associated with decreased MG accumulation. Increasing the glucose concentration in cultured macrophages was sufficient to cause accumulation of endogenous MG-adducts which correlated with increased Tnf and Il1b expression during classical activation. Use of the MG antagonist, aminoguanidine, led to a significant decrease in Tnf and Il1b expression in both mouse macrophages and in the THP-1 human macrophage cell line. Although off-target effects cannot be ruled out, these results are consistent with the possibility that MG regulates cytokine expression in classically activated macrophages. Collectively, this work suggests that HIF-1α stabilization is upstream of MG accumulation and that targeting the activity of HIF-1α in macrophages may be therapeutic during sepsis by limiting endogenous MG accumulation.

Chemical Investigation and Regulation of Adipogenic Differentiation of Cultivated Moringa oleifera.

Background/Objectives: Moringa oleifera is a matrix plant with the high potential to cure several diseases with its medicinal and ethnopharmacological value and nutraceutical properties. In this study, we investigated the chemical and biological properties of this plant cultivated in our local region. Methods: Leaves, roots, seeds, stem bark, and twigs of oleifera were extracted and evaluated bioactivities targeting intracellular lipid accumulation and adipocyte differentiation in 3T3-L1 preadipocytes, and UHPLC-ESI-Orbitrap-MS/MS-Based molecular networking guided isolation and dereplication of metabolites from these extracts. Results: Five extracts of different organs of M. oleifera significantly stimulated intracellular lipid accumulation and adipocyte differentiation in 3T3-L1 preadipocytes in a concentration-dependent manner. These extracts markedly increased the expression of genes related to adipogenesis and lipogenesis. Notably, these extracts promoted peroxisome proliferator-activated receptor γ (PPARγ) activity and the expression of its target genes, including phosphoenolpyruvate carboxykinase, fatty acid-binding protein 4, and perilipin-2. These adipogenic and lipogenic effects of Moringa extracts through the regulation of PPARγ activity suggests their potential efficacy in preventing or treating type 2 diabetes. Furthermore, chemical investigation revealed high contents of phytonutrients as rich sources of secondary metabolites including glycosides, flavones, fatty acids, phenolics, and other compounds. In addition, in silico studies on major components of these extracts revealed the bioavailability of major components through their binding affinity to respective proteins targeting adipocyte differentiation.

Molecular determinants of phospholipid treatment to reduce intracellular cholesterol accumulation in NPC1 deficiency

Niemann-Pick type C (NPC) disease, caused by mutations in the NPC1 or NPC2 genes, leads to abnormal intracellular cholesterol accumulation in late endosomes/lysosomes (LE/LY). Exogenous enrichment with lysobisphosphatidic acid (LBPA), also known as bis-monoacylglycerol phosphate or BMP, either directly or via the LBPA precursor phosphatidylglycerol (PG), has been investigated as a therapeutic intervention to reduce cholesterol accumulation in NPC disease. Here we report the effects of stereoisomer configuration and acyl chain composition of LBPA on cholesterol clearance in NPC1-deficient cells. We find that S,R, S,S, and S,R LBPA stereoisomers behaved similarly, with all 3 compounds leading to comparable reductions in filipin staining in two NPC1-deficient human fibroblast cell lines. Examination of several LBPA molecular species containing one or two mono- or polyunsaturated acyl chains showed that all LBPA species containing one 18:1 chain significantly reduced cholesterol accumulation, whereas the shorter chain species di-14:0 LBPA had little effect on cholesterol clearance in NPC1 deficient cells. Since cholesterol accumulation in NPC1 deficient cells can also be cleared by PG incubation, we used non-hydrolyzable PG analogues to determine whether conversion to LBPA is required for sterol clearance, or whether PG itself is effective. The results showed that non-hydrolyzable PG species were not appreciably converted to LBPA and showed virtually no cholesterol clearance efficacy in NPC1 deficient cells, supporting the notion that LBPA is the active agent promoting LE/LY cholesterol clearance. Overall these studies are helping to define the molecular requirements for potential therapeutic use of LBPA as an option for addressing NPC disease.

Hepatocyte activation and liver injury following cerebral ischemia promote HMGB1-mediated hepcidin upregulation in hepatocytes and regulation of systemic iron levels.

We previously reported that high mobility group box 1 (HMGB1), a danger-associated molecular pattern (DAMP), increases intracellular iron levels in the postischemic brain by upregulating hepcidin, a key regulator of iron homeostasis, triggering ferroptosis. Since hepatocytes are the primary cells that produce hepcidin and control systemic iron levels, we investigated whether cerebral ischemia induces hepcidin upregulation in hepatocytes. Following middle cerebral artery occlusion (MCAO) in a rodent model, significant liver injury was observed. This injury was evidenced by significantly elevated Eckhoff's scores and increased serum levels of alanine aminotransferase (ALT) and aspartate aminotransferase (AST). Additionally, total iron levels were significantly elevated in the liver, with intracellular iron accumulation detected in hepatocytes. Hepcidin expression in the liver, which is primarily localized in hepatocytes, increased significantly starting at 3 h after MCAO and continued to increase rapidly, reaching a peak at 24 h. Interestingly, HMGB1 levels in the liver were also significantly elevated after MCAO, with the disulfide form of HMGB1 being the major subtype. In vitro experiments using AML12 hepatocytes showed that recombinant disulfide HMGB1 significantly upregulated hepcidin expression in a Toll-like receptor 4 (TLR4)- and RAGE-dependent manner. Furthermore, treatment with a ROS scavenger and a peptide HMGB1 antagonist revealed that both ROS generation and HMGB1 induction contributed to hepatocyte activation and liver damage following MCAO-reperfusion. In conclusion, this study revealed that cerebral ischemia triggers hepatocyte activation and liver injury. HMGB1 potently induces hepcidin not only in the brain but also in the liver, thereby influencing systemic iron homeostasis following ischemic stroke.