Ganglioside GM1 Research Articles

Effect of CFTR modulators Elexacaftor/Tezacaftor/Ivacaftor on lipid metabolism in human bronchial epithelial cells.

Cystic Fibrosis (CF) is a life-threatening hereditary disease resulting from mutations in the Cystic Fibrosis Transmembrane Conductance Regulator (CFTR) gene that encodes a chloride channel essential for ion transport in epithelial cells. Mutations in CFTR, notably the prevalent F508del mutation, impair chloride transport, severely affecting the respiratory system and leading to recurrent infections. Recent therapeutic advancements include CFTR modulators such as ETI, a combination of two correctors (Elexacaftor and Tezacaftor) and a potentiator (Ivacaftor), that can improve CFTR function in patients with the F508del mutation. This study investigated ETI's impact on the maturation of the mutated CFTR, the expression levels of its scaffolding proteins, and lipid composition of cells using bronchial epithelial cell lines expressing both wild-type and F508del CFTR. Our findings revealed that ETI treatment enhances CFTR and its scaffolding proteins expression and aids in rescuing mature F508del CFTR, causing also significant alterations in the lipid profile including reduced levels of lactosylceramide and increased content of gangliosides GM1 and GD1a. These changes were linked to ETI's influence on enzymes involved in the sphingolipid metabolism, in particular GM3 synthase and sialidase. Through this work, we aim to deepen understanding CFTR interactions with lipids, and to elucidate the mechanisms of action of CFTR modulators. Our findings may support the development of potential therapeutic strategies contributing to the ongoing efforts to design effective correctors and potentiators for CF treatment.

Clinical and biochemical abnormalities in a feline model of GM2 activator deficiency

Though it has no catalytic activity toward GM2 ganglioside, the GM2 activator protein (GM2A) is essential for ganglioside hydrolysis by facilitating the action of lysosomal ß-N-acetylhexosaminidase. GM2A deficiency results in death in early childhood due to rapid central nervous system deterioration similar to the related GM2 gangliosidoses, Tay-Sachs disease and Sandhoff disease. This manuscript further characterizes a feline model of GM2A deficiency with a focus on clinical and biochemical parameters that may be useful as benchmarks for translational therapeutic research. The GM2A deficient cat has clinical features consistent with the human condition, including isointensity of gray and white matter of the brain on T2-weighted MRI; MR spectroscopic changes of brain metabolites consistent with gliosis, neuronal injury and demyelination; rhythmical slowing of cerebral cortical activation on electroencephalography; and elevation of aspartate aminotransferase and lactate dehydrogenase in cerebrospinal fluid. Biochemically, the brain of GM2A deficient cats has storage of GM2 and GA2 ganglioside coincident with increased hexosaminidase activity toward a standard synthetic substrate. Also, the brain of GM2A deficient cats has increased levels of lyso-platelet activating factor and lyso-phosphatidylcholine, which may serve as novel biomarkers of disease progression and provide insights into pathogenic mechanisms.

Mechanisms by which Ganglioside GM1, a specific type of glycosphingolipid, ameliorates BMAA-induced neurotoxicity in early-life stage of zebrafish embryos.

The neurotoxin β-methylamino-L-alanine (BMAA) produced by cyanobacteria is widely present in foods and dietary supplements, posing a significant threat to human health. Ganglioside GM1 (GM1) has demonstrated potential for treating neurodegenerative diseases; however, its ability to prevent BMAA-induced neurotoxicity remains uncertain. In this study, zebrafish embryos were treated with Ganglioside GM1 to investigate its neuroprotective effects against BMAA exposure and the underlying mechanisms. Exposure to BMAA (400μM) resulted in increased malformation rate and heart rates in zebrafish embryos at 72h post-fertilization, along with the decreased survival rates. Conversely, GM1 intervention rescued BMAA-induced movement disorders and brain cell apoptosis, and oxidative stress was alleviated. In addition, GM1 inhibited the neurotoxic effects of BMAA in zebrafish embryos, as indicated by the up-regulation of genes related to neuron development (gpx1a, bdnf, ngfb, and islet-1) and the down-regulations of neurodegeneration-related genes (cdk5, gfap, and nptxr). GM1 treatment restored 261 differentially expressed genes (DEGs) identified through RNA sequencing, with the most enriched DEGs related to the mitogen-activated protein kinase (MAPK) signaling pathway (P<0.05, 47 genes). GM1 modulated MAPK-targeted gene expression at the mRNA level. These findings suggest that GM1 alleviates BMAA-induced neurotoxicity in the early-life stage of zebrafish embryos. The neuroprotective mechanism may involve the MAPK pathway, offering new insights into lipid signaling for the prevention of neurotoxic hazards to biological health.

Dysregulation of the NLRP3 Inflammasome and Promotion of Disease by IL-1β in a Murine Model of Sandhoff Disease.

Sandhoff disease (SD) is a progressive neurodegenerative lysosomal storage disorder characterized by GM2 ganglioside accumulation as a result of mutations in the HEXB gene, which encodes the β-subunit of the enzyme β-hexosaminidase. Lysosomal storage of GM2 triggers inflammation in the CNS and periphery. The NLRP3 inflammasome is an important coordinator of pro-inflammatory responses, and we have investigated its regulation in murine SD. The NLRP3 inflammasome requires two signals, lipopolysaccharide (LPS) and ATP, to prime and activate the complex, respectively, leading to IL-1β secretion. Peritoneal, but not bone-marrow-derived, macrophages from symptomatic SD mice, but not those from pre-symptomatic animals, secrete the cytokine following priming with LPS with no requirement for activation with ATP, suggesting that such NLRP3 deregulation is related to the extent of glycosphingolipid storage. Dysregulated production of IL-1β was dependent upon caspase activity but not cathepsin B. We investigated the role of IL-1β in SD pathology using two approaches: the creation of hexb-/-Il1r1-/- double knockout mice or by treating hexb-/- animals with anakinra, a recombinant form of the IL-1 receptor antagonist, IL-1Ra. Both resulted in modest but significant extensions in lifespan and improvement of neurological function. These data demonstrate that IL-1β actively participates in the disease process and provides proof-of-principle that blockade of the pro-inflammatory cytokine IL-1β may provide benefits to patients.

Precursor of H-Type II Histo-Blood Group Antigen and Subterminal Sialic Acids on Gangliosides Are Significantly Implicated in Cell Entry and Infection by a Porcine P[11] Rotavirus

Rotaviruses, non-enveloped viruses with a double-stranded RNA genome, are the leading etiological pathogen of acute gastroenteritis in young children and animals. The P[11] genotype of rotaviruses exhibits a tropism for neonates. In the present study, a binding assay using synthetic oligosaccharides demonstrated that the VP8* protein of P[11] porcine rotavirus (PRV) strain 4555 binds to lacto-N-neotetraose (LNnT) with the sequence Galβ1,4-GlcNAcβ1,3-Galβ1,4-Glc, one of the core parts of histo-blood group antigen (HBGA) and milk glycans. However, infections were significantly inhibited by blocking of endogenous monosialoganglioside (GM) GM1a with cholera toxin B subunit and preincubation of the virus with exogenous GM1a, suggesting that GM1a is involved in the infection of P[11] PRV 4555. In addition to GM1a, preincubation of the virus with exogenous disialogangliosides (GD) GD1a, GD1b, and trisialoganglioside (GT) GT1b also prevented infection. In contrast, exogenous ganglioside GM3 only inhibited infections at an early time point, and exogenous asyalosphingolipids GA1 and LacCer did not show any inhibitory effect on infections. This indicates that P[11] PRV 4555 preferentially utilizes gangliosides containing subterminal sialic acids. Further experiments revealed that P[11] PRV 4555 infections were prevented by preincubation of the virus with Neu5Ac and Neu5Gc. These results confirmed that sialic acids are essential for P[11] PRV 4555 cell entry, despite the classification as NA-resistant strain. Overall, our results proved that P[11] rotavirus not only binds to the Gal-GlcNAc motif but also utilizes gangliosides containing subterminal sialic acids.

Synergistic effects of neuroprotective drugs with intravenous recombinant tissue plasminogen activator in acute ischemic stroke: A Bayesian network meta-analysis.

Neuroprotective drugs as adjunctive therapy for adults with acute ischemic stroke (AIS) remains contentious. This study summarizes the latest evidence regarding the benefits of neuroprotective agents combined with intravenous recombinant tissue plasminogen activator (rt-PA) intravenous thrombolysis. This study conducted a structured search of PubMed, the Cochrane Library, EMBASE, Wanfang Data, and CNKI databases from their inception to March 2024. Grey literature was also searched. The outcomes included efficacy (National Institutes of Health Stroke Scale (NIHSS) score and Barthel Index (BI) score) and safety (rate of adverse reactions). A total of 70 randomized controlled trials were selected for this network meta-analysis (NMA), encompassing 4,140 patients with AIS treated using different neuroprotective agents plus RT-PA, while 4,012 patients with AIS were in control groups. The top three treatments for NIHSS scores at the 2-week follow-up were Edaravone Dexborneo with 0.9 mg/kg rt-PA, Edaravone with 0.9 mg/kg rt-PA, and HUK with 0.9 mg/kg rt-PA. HUK with 0.9 mg/kg rt-PA, Dl-3n-butylphthalide with 0.9 mg/kg rt-PA, and Edaravone Dexborneo with 0.9 mg/kg rt-PA were ranked the top three for BI scores at the 2-week follow-up. The top three treatments with the lowest adverse effect rates were 0.6 mg/kg rt-PA, HUK with 0.9 mg/kg rt-PA, and Edaravone Dexborneo with 0.9 mg/kg rt-PA due to their excellent safety profiles. Compared to rt-PA alone, the combination treatments of Edaravone+rt-PA, Edaravone Dexborneol+rt-PA, HUK+rt-PA, Dl-3n-butylphthalide+rt-PA, and Ganglioside GM1+rt-PA have shown superior efficacy. This NMA suggest that combination therapies of neuroprotective agents and rt-PA can offer better outcomes for patients with AIS. The results support the potential integration of these combination therapies into standard AIS treatment, aiming for improved patient outcomes and personalized therapeutic approaches.

Reactivation of mTOR signaling slows neurodegeneration in a lysosomal sphingolipid storage disease.

Sandhoff disease, a lysosomal storage disorder, is caused by pathogenic variants in the HEXB gene, resulting in the loss of β-hexosaminidase activity and accumulation of sphingolipids including GM2 ganglioside. This accumulation occurs primarily in neurons, and leads to progressive neurodegeneration through a largely unknown process. Lysosomal storage diseases often exhibit dysfunctional mTOR signaling, a pathway crucial for proper neuronal development and function. In this study, Sandhoff disease model mice exhibited reduced mTOR signaling in the brain. To test if restoring mTOR signaling could improve the disease phenotype, we genetically reduced expression of the mTOR inhibitor Tsc2 in these mice. Sandhoff disease mice with reactivated mTOR signaling displayed increased survival rates and motor function, especially in females, increased dendritic-spine density, and reduced neurodegeneration. Tsc2 reduction also partially rescued aberrant synaptic function-related gene expression. These findings imply that enhancing mTOR signaling could be a potential therapeutic strategy for lysosomal-based neurodegenerative diseases.

Specificity of widely used lectins as probed with oligosaccharide and plant polysaccharide arrays.

Glycan-binding specificity was studied for Jacalin, RCA 120, SBA, PHA-L, PHA-E, WGA, UEA, AAL, LTL, LEL, SNA, DSA, LCA, MAH and Con A, lectins widely used in histochemistry. Oligosaccharide- and polysaccharide-based glycan arrays were applied. Expected specificity was confirmed for only 6 of the 15 lectins and the glycan binding profiles of some lectins were dramatically broader than generally accepted. WGA, LEL and DSA known as chitooligosaccharide-specific, were unexpectedly polyreactive, binding to other glycans with the same affinity as to chitobiose, ABH antigens and oligolactosamines (unsubstituted and sialylated). SBA, in addition to expected binding to glycans with terminal GalNAcα, also had high affinity for the GM1 ganglioside. MAH demonstrated much higher affinity to a variety of sulfated glycans compared to Neu5Acα2-3Galβ1-3GalNAcα. Contrary to the common view, LCA demonstrated the maximum binding to (GlcNAcβ1-2Manα1)2-3,6-Manβ1-4GlcNAcβ1-4GlcNAc N-glycan, while it had no interaction with corresponding Gal or Neu5Ac terminated versions. This observed polyreactivity of some lectins casts doubt on their use in accurately determining the presence of a specific glycan structure by histochemical studies. However, comparisons of sera from healthy and diseased individuals with help of a lectin array can easily establish differences in glycosylation patterns and presumptive glycan identities, which can later be clarified using more accurate methods of structural analysis.

Retraction Note: Silencing of membrane-associated sialidase Neu3 diminishes apoptosis resistance and triggers megakaryocytic differentiation of chronic myeloid leukemic cells K562 through the increase of ganglioside GM3

Retraction Note: Silencing of membrane-associated sialidase Neu3 diminishes apoptosis resistance and triggers megakaryocytic differentiation of chronic myeloid leukemic cells K562 through the increase of ganglioside GM3

Intravenous gene therapy improves lifespan and clinical outcomes in feline Sandhoff Disease.

Sandhoff Disease (SD), a fatal neurodegenerative disorder, is caused by the absence of ß-hexosaminidase (Hex) and subsequent accumulation of GM2 ganglioside in lysosomes. Previous studies have led to adeno-associated virus (AAV) gene therapy for children with GM2 gangliosidosis in both expanded access and Phase I/II clinical trials via intracranial and/or cerebrospinal fluid-based delivery. The current study investigated intravenous (IV) gene therapy of SD cats, treated at one month of age with a bicistronic AAV vector. While untreated SD cats lived to 4.3±0.2 months, cats treated with low and high doses lived to 8.3±1.2 and 12.4±2.7 months, respectively. In-life assessments revealed clear clinical benefit of AAV treatment, with the most dramatic improvement seen in the reduction of overt full-body tremors. Cerebrospinal fluid levels of aspartate aminotransferase (AST) and lactate dehydrogenase (LDH) were decreased, indicating a reduction of cell damage within the central nervous system. Magnetic resonance imaging (MRI) and spectroscopy (MRS) acquired on a 7 Tesla scanner indicated that structural pathology and metabolite abnormalities are partially normalized by AAV treatment. Dose-dependent reduction of GM2 ganglioside storage and increases in Hex activity were most substantial in the caudal regions of the brain and in the spinal cord. Immunohistochemistry revealed reduction in neuroinflammatory cell populations and partial correction of myelin deficits. These results support the dose-dependent efficacy of AAV delivered IV for significant restoration of clinical metrics and Hex function in a feline model of SD.

4-Phenylbutyric acid mitigates ER stress-induced neurodegeneration in the spinal cords of a GM2 gangliosidosis mouse model.

Sandhoff disease (SD), a fatal and rare lysosomal storage disorder (LSD), is caused by a deficiency of the enzyme β-hexosaminidase B and leads to severe accumulation of GM2 gangliosides in lysosomes, primarily within the central nervous system (CNS). This accumulation results in severe neurological impairment, lower motor neuron disease, and death. Currently, there are no effective therapies available for SD. Here, we explored the role of endoplasmic reticulum (ER) stress in the spinal cord during disease progression in an established mouse model of SD and revealed the beneficial outcome of off-label treatment with the FDA-approved drug, 4-phenylbutyric acid (4-PBA). We analyzed the expression and localization of ER stress and cellular apoptosis markers, which revealed significant upregulation of these factors within motor neurons. Additionally, we observed a > 50% reduction in neuronal numbers throughout all spinal cord regions. Our studies also tested the impact of the chemical chaperone 4-PBA on ER stress in mice, and following administration, we observed significant improvements in motor neuromuscular function and life span throughout disease progression. 4-PBA treatment significantly reduced apoptosis in spinal cord neurons and increased the number of choline acetyltransferase (ChAT)-positive neurons, with little effect on astrogliosis or sensory interneurons. Overall, this study provides strong evidence for the role of chronic ER stress in the pathophysiology of SD and highlights 4-PBA as a promising therapeutic treatment for SD and potentially other related LSDs.

Mechanics of poly-arginine adsorption onto cell membrane by GM1 and their cluster forming: Coarse-grained molecular dynamics study

Ganglioside GM1 is a crucial glycolipid in neuronal cells, playing significant roles in various biological processes such as pathogen recognition, signal transduction, and protein sorting. Poly-arginine, widely used as a template for cell-penetrating peptides design, is highly valuable for molecular cargo delivery and information transmission. Investigating the interaction mechanisms and physicochemical principles of poly-arginine with GM1-containing cell membranes is essential for understanding the functions of specific cellular components and for developing novel drugs. In this study, we employed coarse-grained molecular dynamics simulations to explore the interaction processes between poly-arginine of varying concentrations and polymerization degrees with model membranes of human brain neuronal cells. Our findings reveal that poly-arginines preferentially adsorb onto GM1 and aggregate into clusters on the membrane, primarily driven by electrostatic interactions, which contributes to membrane stabilization. Additionally, poly-arginine shows a higher affinity for membranes with elevated GM1 concentrations, highlighting its potential for targeting specific membrane compositions. These insights are crucial for designing molecular targets and understanding the biophysical mechanisms in lipidomics using high-performance computational simulation methods.

Abnormally accumulated GM2 ganglioside contributes to skeletal deformity in Tay-Sachs mice.

Tay-Sachs Disease is a rare lysosomal storage disorder caused by mutations in the HEXA gene, responsible for the degradation of ganglioside GM2. In addition to progressive neurodegeneration, Tay-Sachs patients display bone anomalies, including kyphosis. Tay-Sachs disease mouse model (Hexa-/-Neu3-/-) shows both neuropathological and clinical abnormalities of the infantile-onset disease phenotype. In this study, we investigated the effects of GM2 accumulation on bone remodeling activity. Here, we evaluated the bone phenotype of 5-month-old Hexa-/-Neu3-/- mice with age-matched control groups using gene expression analysis, bone plasma biomarker analysis, and micro-computed tomography. We demonstrated lower plasma alkaline phosphatase activity and calcium levels with increased tartrate-resistant acid phosphatase levels, indicating reduced bone remodeling activity in mice. Consistently, gene expression analysis confirmed osteoblast reduction and osteoclast induction in the femur of mice. Micro-computed tomography and analysis show reduced trabecular bone volume, mineral density, number, and thickness in Hexa-/-Neu3-/- mice. In conclusion, we demonstrated that abnormal GM2 ganglioside accumulation significantly triggers skeletal abnormality in Tay-Sachs mice. We suggest that further investigation of the molecular basis of bone structure anomalies is necessary to elucidate new therapeutic targets that preventthe progression ofbone symptoms and improve the life standards of Tay-Sachs patients. KEY MESSAGES: We detected the markers of bone loss-associated disorders such as osteopenia and osteoporosis in the Tay-Sachs disease mice model Hexa-/-Neu3-/-. We also demonstrated for the first time there is an increase in trabecular spacing and a reduction in trabecular thickness and number indicating skeletal abnormalities in mice model using micro-CT analysis.

Potential Disease-Modifying Effects of Ganglioside GM1 Pulse Treatment on Spinocerebellar Ataxia Type 3, a Parallel-Group, Double-Blind, Randomized, Controlled Trial.

Spinocerebellar ataxia type 3 (SCA3) is an autosomal dominant inherited neurodegenerative disorder for which there is currently no cure, nor effective treatment strategy. Our aim was to investigate the safety and efficacy of high-dose ganglioside GM1 (ganglioside-monosialic acid) pulse treatment in patients with SCA3. Patients were randomly allocated to receive either high-dose GM1 (400 mg on the first day followed by 200 mg/day), low-dose GM1 (40 mg/day), or placebo (normal saline) for 4 weeks. The primary outcome, assessed by measuring the change in the Scale for the Assessment and Rating of Ataxia (SARA) scores from baseline to 12 weeks post-treatment, is central to evaluating treatment efficacy. Secondary outcomesincluded changes in the International Cooperative Ataxia Rating Scale (ICARS) score, Barthel Index of Activities of Daily Living (ADL), and plasma and cerebrospinal fluid (CSF) GABA levels. Safety was assessed in all treated patients. A total of 48 patients with SCA3 were enrolled in this study. After 12 weeks, data from 43 patients were included in the efficacy analysis (intention-to-treat analysis). The least-squares mean change in the SARA score from baseline to 12 weeks post-treatment was -3.80 (standard error [SE], 0.39; 95% confidence interval [CI], -4.58 to -3.02) in the high-dose GM1 group, 0.34 (SE, 0.40; 95% CI, -0.46 to 1.13) in the low-dose GM1 group, and 0.73 (SE, 0.40; 95% CI, -0.07 to 1.52) in the placebo group, respectively. Secondary outcomes showed improvements in the ICARS score, Barthel Index of ADL, and plasma and CSF GABA levels in the high-dose GM1 group compared to the low-dose GM1 and placebo groups. All treatments were well-tolerated and safe. High-dose GM1 treatment significantly ameliorated ataxic symptoms in patients with SCA3. © 2024 International Parkinson and Movement Disorder Society.

Targeting GM2 Ganglioside Accumulation in Dementia: Current Therapeutic Approaches and Future Directions.

Dementia in neurodegenerative diseases, such as Alzheimer's disease (AD), Parkinson's disease (PD), and dementia with Lewy bodies (DLB) is a progressive neurological condition affecting millions worldwide. The amphiphilic molecule GM2 gangliosides are abundant in the human brain and play important roles in neuronal development, intercellular recognition, myelin stabilization, and signal transduction. GM2 ganglioside's degradation requires hexosaminidase A (HexA), a heterodimer composed of an α subunit encoded by HEXA and a β subunit encoded by HEXB. The hydrolysis of GM2 also requires a non-enzymatic protein, the GM2 activator protein (GM2-AP), encoded by GM2A. Pathogenic mutations of HEXA, HEXB, and GM2A are responsible for autosomal recessive diseases known as GM2 gangliosidosis, caused by the excessive intralysosomal accumulation of GM2 gangliosides. In AD, PD and DLB, GM2 ganglioside accumulation is reported to facilitate Aβ and α-synuclein aggregation into toxic oligomers and plaques through activation of downstream signaling pathways, such as protein kinase C (PKC) and oxidative stress factors. This review explored the potential role of GM2 ganglioside alteration in toxic protein aggregations and its related signaling pathways leading to neurodegenerative diseases. Further review explored potential therapeutic approaches, which include synthetic and phytomolecules targeting GM2 ganglioside accumulation in the brain, holding a promise for providing new and effective management for dementia.

Investigating the effects of empagliflozin on myocardial metabolic and lipid profile in healthy and metabolic syndrome murine models following acute myocardial infarction

Abstract Background/Introduction Empagliflozin (EMPA) is a sodium/glucose co-transporter type 2 inhibitor with clinically documented cardioprotective effect. However, the mechanism of cardioprotection remains elusive. We have previously shown that Western diet induces metabolic syndrome (MS) and deteriorates cardiac function in mice, whereas EMPA treatment for 6 weeks prevents this damage. Also, EMPA administration for 6 weeks suppresses ischemia/reperfusion (I/R) injury in mice, independent of the presence of MS. Purpose The aim of the present study is to investigate whether changes in myocardial metabolic and lipid profile, induced by EMPA treatment, are responsible for its cardioprotective effect in the setting of myocardial I/R injury. Methods C57Bl6 mice received chow diet or Western diet for 14 weeks. At week 8, mice from each dietary group were randomized into 3 subgroups: 1. Control - Sham surgery (5% DMSO-SHAM), 2. Control - I/R (5% DMSO-I/R) and 3. EMPA (10mg/kg/day in 5% DMSO) - I/R (EMPA-I/R) and received the corresponding treatment by daily per os administration for 6 weeks. At week 14, mice were subjected to 30 minutes of I, followed by 2 hours of R, or sham surgery. Myocardial tissue was harvested at the end of R, and metabolomic and lipidomic analysis was performed by nuclear magnetic resonance spectroscopy and mass spectrometry, respectively. Body weight, as well as blood glucose and cholesterol levels were assessed at baseline and at the end of the administrations. Results EMPA administration reduced body weight, as well as blood glucose and cholesterol levels in animals with MS. EMPA decreased anaerobic glycolysis products (UDP-glucose, Lactic acid) and ketone bodies (β-hydroxybutyrate, acetoacetic acid) in both healthy animals and mice with MS. Additionally, an increase in ATP, accompanied by a decrease in AMP and ADP were observed in the EMPA-I/R group, compared to the DMSO-I/R group. Regarding the lipidomic analysis, gangliosides GM3 emerged as the major lipid group decreased by EMPA treatment. Lastly, despite significant changes were presented in the metabolic and lipid profile between healthy animals and those with MS, the effects of EMPA on myocardial metabolic and lipid profile were the same, regardless of the presence of MS. Conclusion(s) EMPA administration induces metabolic changes in the heart tissue and improves myocardial energetics upon myocardial I/R injury. Also, EMPA suppresses gangliosides GM3, a lipid group that has been associated with neutrophil activation and recruitment. Importantly, the effects of EMPA on myocardial metabolic and lipid profile following I/R is independent of the presence of MS.

GM1 Oligosaccharide Ameliorates Rett Syndrome Phenotypes In Vitro and In Vivo via Trk Receptor Activation.

Rett syndrome (RTT) is a severe neurodevelopmental disorder primarily caused by mutations in the methyl-CpG binding protein 2 (MECP2) gene. Despite advancements in research, no cure exists due to an incomplete understanding of the molecular effects of MeCP2 deficiency. Previous studies have identified impaired tropomyosin receptor kinase (Trk) neurotrophin (NTP) signaling and mitochondrial redox imbalances as key drivers of the pathology. Moreover, altered glycosphingolipid metabolism has been reported in RTT. GM1 ganglioside is a known regulator of the nervous system, and growing evidence indicates its importance in maintaining neuronal homeostasis via its oligosaccharide chain, coded as GM1-OS. GM1-OS directly interacts with the Trk receptors on the cell surface, triggering neurotrophic and neuroprotective pathways in neurons. In this study, we demonstrate that GM1-OS ameliorates RTT deficits in the Mecp2-null model. GM1-OS restored synaptogenesis and reduced mitochondrial oxidative stress of Mecp2-knock-out (ko) cortical neurons. When administered in vivo, GM1-OS mitigated RTT-like symptoms. Our findings indicate that GM1-OS effects were mediated by Trk receptor activation on the neuron's plasma membrane. Overall, our results highlight GM1-OS as a promising candidate for RTT treatment.

Antibody-targeted T cells and natural killer cells for cancer immunotherapy

BackgroundAdoptive cell cancer therapies aim to re-engineer a patient’s immune cells to mount an anti-cancer response. Chimeric antigen receptor T and natural killer cells have been engineered and proved successful in treating some cancers; however, the genetic methods for engineering are laborious, expensive, and inefficient and can cause severe toxicities when they over-proliferate.ResultsWe examined whether the cell-killing capacity of activated T and NK cells could be targeted to cancer cells by anchoring antibodies to their cell surface. Using metabolic glycoengineering to introduce azide moieties to the cellular surface, we covalently attached a dibenzocyclooctyne-modified antibody using the strain-promoted alkyne azide cycloaddition reaction, creating antibody-conjugated T and NK cells. We targeted the immune cells to tumors possessing the xenoantigen, N-glycolyl neuraminic acid GM3 ganglioside, using the 14F7hT antibody. These activated T and NK cells are “armed” with tumour-homing capabilities that specifically lyses antigen-positive cancer cells without off-target toxicities. Moreover, when exposed to target cells, 14F7hT-conjugated T cells that are not preactivated exhibit increased perforin, granzyme, CD69, and CD25 expression and specific cell killing.ConclusionsThis research shows the potential for a non-genetic method for redirecting cytotoxic immune cells as a feasible and effective approach for tumor-targeted cell immunotherapy.Graphical

Alpha-hemolysin promotes internalization of Staphylococcus aureus into human lung epithelial cells via caveolin-1- and cholesterol-rich lipid rafts

Staphylococcus aureus is a pathogen associated with severe respiratory infections. The ability of S. aureus to internalize into lung epithelial cells complicates the treatment of respiratory infections caused by this bacterium. In the intracellular environment, S. aureus can avoid elimination by the immune system and the action of circulating antibiotics. Consequently, interfering with S. aureus internalization may represent a promising adjunctive therapeutic strategy to enhance the efficacy of conventional treatments. Here, we investigated the host-pathogen molecular interactions involved in S. aureus internalization into human lung epithelial cells. Lipid raft-mediated endocytosis was identified as the main entry mechanism. Thus, bacterial internalization was significantly reduced after the disruption of lipid rafts with methyl-β-cyclodextrin. Confocal microscopy confirmed the colocalization of S. aureus with lipid raft markers such as ganglioside GM1 and caveolin-1. Adhesion of S. aureus to α5β1 integrin on lung epithelial cells via fibronectin-binding proteins (FnBPs) was a prerequisite for bacterial internalization. A mutant S. aureus strain deficient in the expression of alpha-hemolysin (Hla) was significantly impaired in its capacity to enter lung epithelial cells despite retaining its capacity to adhere. This suggests a direct involvement of Hla in the bacterial internalization process. Among the receptors for Hla located in lipid rafts, caveolin-1 was essential for S. aureus internalization, whereas ADAM10 was dispensable for this process. In conclusion, this study supports a significant role of lipid rafts in S. aureus internalization into human lung epithelial cells and highlights the interaction between bacterial Hla and host caveolin-1 as crucial for the internalization process.

Phosphatidic acid is involved in regulation of autophagy in neurons in vitro and in vivo

Major depressive disorder (MDD) is a common and severe psychiatric disease, which does not only lead to variety of neuropsychiatric symptoms, but unfortunately in a relatively large proportion of cases also to suicide. The pathogenesis of MDD still requires definition. We have previously shown that ceramide is increased in the blood plasma of patients with MDD. In mouse models of MDD, which are induced by treatment with corticosterone or application of chronic unpredictable stress, increased blood plasma ceramide also increased and caused an inhibition of phospholipase D in endothelial cells of the hippocampus and reduced phosphatidic acid levels in the hippocampus. Here, we demonstrated that corticosterone treatment of PC12 cells resulted in reduced cellular autophagy, which is corrected by treatment with phosphatidic acid. In vivo, treatment of mice with corticosterone or chronic unpredictable stress also reduced autophagy in hippocampus neurons. Autophagy was normalized upon i.v. injection of phosphatidic acid in these mouse models of MDD. In an attempt to identify targets of phosphatidic acid in neurons, we demonstrated that corticosterone reduced levels of the ganglioside GM1 in PC-12 cells and the hippocampus of mice, which were normalized by treatment of cells or i.v. injection of mice with phosphatidic acid. GM1 application also normalized autophagy in cultured neurons. Phosphatidic acid and GM1 corrected stress-induced alterations in behavior, i.e., mainly anxiety and anhedonia, in experimental MDD in mice. Our data suggest that phosphatidic acid may regulate via GM1 autophagy in neurons.