MALDI TIMS IMS Reveals Ganglioside Molecular Diversity within Murine S. aureus Kidney Tissue Abscesses.

Gangliosides play important roles in innate and adaptive immunity. The high degree of structural heterogeneity results in significant variability in ganglioside expression patterns and greatly complicates linking structure and function. Structural characterization at the site of infection is essential in elucidating host ganglioside function in response to invading pathogens, such as Staphylococcus aureus (S. aureus). Matrix-assisted laser desorption/ionization imaging mass spectrometry (MALDI IMS) enables high-specificity spatial investigation of intact gangliosides. Here, ganglioside structural and spatial heterogeneity within an S. aureus-infected mouse kidney abscess was characterized. Differences in spatial distributions were observed for gangliosides of different classes and those that differ in ceramide chain composition and oligosaccharide-bound sialic acid. Furthermore, integrating trapped ion mobility spectrometry (TIMS) allowed for the gas-phase separation and visualization of monosialylated ganglioside isomers that differ in sialic acid type and position. The isomers differ in spatial distributions within the host-pathogen interface, where molecular patterns revealed new molecular zones in the abscess previously unidentified by traditional histology.

Co-registration of MALDI-MSI and histology demonstrates gangliosides co-localize with amyloid beta plaques in Alzheimer's disease.

Alzheimer's disease (AD) is a progressive neurological condition characterized by impaired cognitive function and behavioral alterations. While AD research historically centered around mis-folded proteins, advances in mass spectrometry techniques have triggered increased exploration of the AD lipidome with lipid dysregulation emerging as a critical player in AD pathogenesis. Gangliosides are a class of glycosphingolipids enriched within the central nervous system. Previous work has suggested a shift in a-series gangliosides from complex (GM1) to simple (GM2 and GM3) species may be related to the development of neurodegenerative disease. In addition, complex gangliosides with 20 carbon sphingosine chains have been shown to increase in the aging brain. In this study, we utilized matrix-assisted laser desorption ionization mass spectrometry imaging (MALDI-MSI) to interrogate the in situ relationship of a-series gangliosides with either 18 or 20 carbon sphingosine chains (d18:1 or d20:1, respectively) in the post-mortem human AD brain. Here, we expanded upon previous literature and demonstrated a significant decrease in the GM1 d20:1 to GM1 d18:1 ratio in regions of the dentate gyrus and entorhinal cortex in AD relative to control brain tissue. Then, we demonstrated that the MALDI-MSI profile of GM3 co-localizes with histologically confirmed amyloid beta (Aß) plaques and found a significant increase in both GM1 and GM3 in proximity to Aß plaques. Collectively, this study demonstrates a perturbation of the ganglioside profile in AD, and validates a pipeline for MALDI-MSI and classic histological staining in the same tissue sections. This demonstrates feasibility for integrating untargeted mass spectrometry imaging approaches into a digital pathology framework.

Case report: Bilateral facial palsy with paresthesias and positive anti-GT1a antibodies.

Bilateral facial palsy with paresthesia (FDP) is a rare variant of GBS, characterized by simultaneous bilateral facial palsy and paresthesia of the distal limbs. Mounting evidence indicates that the presence of anti-GT1a IgG has a pathogenic role as an effector molecule in the development of cranial nerve palsies in certain patients with GBS, whereas anti-GT1a antibody is rarely presented positive in FDP. Here, we report the case of a 33-year-old male diagnosed with FDP presented with acute onset of bilateral facial palsy and slight paresthesias at the feet as the only neurological manifestation. An antecedent infection with no identifiable reason for the fever or skin eruptions was noted in the patient. He also exhibited cerebrospinal fluid albuminocytologic dissociation and abnormal nerve conduction studies. Notably, the testing of specific serum anti-gangliosides showed positive anti-GT1a IgG/IgM Ab. The patient responded well to intravenous immunoglobulin therapy. This case brings awareness to a rare variant of GBS, and provides the first indication that anti-GT1a antibodies play a causative role in the development of FDP. The case also suggests that prompt management with IVIG should be implemented if FDP is diagnosed.

The Effect of Intranasal Administration of Gangliosides on the Viability of CA1 Hippocampal Neurons in Rat Two-Vessel Occlusion Model of Forebrain Ischemia/Reperfusion Injury.

Intranasal administration of total bovine brain gangliosides (6 mg/kg) to rats protected the CA1 hippocampal neurons from the death caused by two-vessel occlusion model (with hypotension) of forebrain ischemia/reperfusion injury. The immunohistochemical reaction of specific antibodies to marker proteins of activated microglia (Iba1) and astrocytes (GFAP) in hippocampal slices revealed the neuroprotective effect of exogenous gangliosides which can be mostly explained by their ability to suppress neuroinflammation and gliosis. The expression of neurotrophic factor BDNF in the CA1 region of hippocampus did not differ in sham-operated rats and animals exposed to ischemia/reperfusion. However, the administration of gangliosides increased the BDNF expression in both control and ischemic groups. The intranasal route of administration allows using lower concentrations of gangliosides preventing the death of hippocampal neurons.

Glycosphingolipids in Osteoarthritis and Cartilage-Regeneration Therapy: Mechanisms and Therapeutic Prospects Based on a Narrative Review of the Literature.

Glycosphingolipids (GSLs), a subtype of glycolipids containing sphingosine, are critical components of vertebrate plasma membranes, playing a pivotal role in cellular signaling and interactions. In human articular cartilage in osteoarthritis (OA), GSL expression is known notably to decrease. This review focuses on the roles of gangliosides, a specific type of GSL, in cartilage degeneration and regeneration, emphasizing their regulatory function in signal transduction. The expression of gangliosides, whether endogenous or augmented exogenously, is regulated at the enzymatic level, targeting specific glycosyltransferases. This regulation has significant implications for the composition of cell-surface gangliosides and their impact on signal transduction in chondrocytes and progenitor cells. Different levels of ganglioside expression can influence signaling pathways in various ways, potentially affecting cell properties, including malignancy. Moreover, gene manipulations against gangliosides have been shown to regulate cartilage metabolisms and chondrocyte differentiation in vivo and in vitro. This review highlights the potential of targeting gangliosides in the development of therapeutic strategies for osteoarthritis and cartilage injury and addresses promising directions for future research and treatment.

PLD3 and PLD4 synthesize S,S-BMP, a key phospholipid enabling lipid degradation in lysosomes.

Bis(monoacylglycero)phosphate (BMP) is an abundant lysosomal phospholipid required for degradation of lipids, in particular gangliosides. Alterations in BMP levels are associated with neurodegenerative diseases. Unlike typical glycerophospholipids, lysosomal BMP has two chiral glycerol carbons in the S (rather than the R) stereo-conformation, protecting it from lysosomal degradation. How this unusual and yet crucial S,S-stereochemistry is achieved is unknown. Here we report that phospholipases D3 and D4 (PLD3 and PLD4) synthesize lysosomal S,S-BMP, with either enzyme catalyzing the critical glycerol stereo-inversion reaction in vitro. Deletion of PLD3 or PLD4 markedly reduced BMP levels in cells or in murine tissues where either enzyme is highly expressed (brain for PLD3; spleen for PLD4), leading to gangliosidosis and lysosomal abnormalities. PLD3 mutants associated with neurodegenerative diseases, including Alzheimer's disease risk, diminished PLD3 catalytic activity. We conclude that PLD3/4 enzymes synthesize lysosomal S,S-BMP, a crucial lipid for maintaining brain health.

Co-registration of MALDI-MSI and histology demonstrates gangliosides co-localize with amyloid beta plaques in Alzheimer's disease.

Alzheimer's disease (AD) is a progressive neurological condition characterized by impaired cognitive function and behavioural alterations. While AD research historically centered around mis-folded proteins, advances in mass spectrometry techniques have triggered increased exploration of the AD lipidome with lipid dysregulation emerging as a critical player in AD pathogenesis. Gangliosides are a class of glycosphingolipids enriched within the central nervous system. Previous work has suggested a shift in a-series gangliosides from complex (GM1) to simple (GM2 and GM3) species may be related to the development of neurodegenerative disease. Additionally, complex gangliosides with 20 carbon sphingosine chains have been shown to increase in the aging brain. In this study, we utilized matrix assisted laser desorption ionization mass spectrometry imaging (MALDI-MSI) to interrogate the in situ relationship of a-series gangliosides with either 18 or 20 carbon sphingosine chains (d18:1 or d20:1 respectively) in the post-mortem human AD brain. Here, we expanded upon previous literature and demonstrated a significant decrease in the GM1 d20:1:GM1 d18:1 ratio in regions of the dentate gyrus and entorhinal cortex in AD relative to control brain tissue. Then we demonstrated that the MALDI-MSI profile of GM3 co-localizes with histologically confirmed amyloid beta (Aß) plaques and found a significant increase in both GM1 and GM3 in proximity to Aß plaques. Collectively these results support past literature and demonstrate a perturbation of the ganglioside profile in AD. Moreover, this work validates a pipeline for MALDI-MSI and classic histological staining in the same tissue sections. This demonstrates feasibility for integrating untargeted mass spectrometry imaging approaches into a digital pathology framework.

Spatial neurolipidomics-MALDI mass spectrometry imaging of lipids in brain pathologies.

Given the complexity of nervous tissues, understanding neurochemical pathophysiology puts high demands on bioanalytical techniques with respect to specificity and sensitivity. Mass spectrometry imaging (MSI) has evolved to become an important, biochemical imaging technology for spatial biology in biological and translational research. The technique facilitates comprehensive, sensitive elucidation of the spatial distribution patterns of drugs, lipids, peptides, and small proteins in situ. Matrix-assisted laser desorption ionization (MALDI)-based MSI is the dominating modality due to its broad applicability and fair compromise of selectivity, sensitivity price, throughput, and ease of use. This is particularly relevant for the analysis of spatial lipid patterns, where no other comparable spatial profiling tools are available. Understanding spatial lipid biology in nervous tissue is therefore a key and emerging application area of MSI research. The aim of this review is to give a concise guide through the MSI workflow for lipid imaging in central nervous system (CNS) tissues and essential parameters to consider while developing and optimizing MSI assays. Further, this review provides a broad overview of key developments and applications of MALDI MSI-based spatial neurolipidomics to map lipid dynamics in neuronal structures, ultimately contributing to a better understanding of neurodegenerative disease pathology.

Glycosphingolipids in congenital disorders of glycosylation (CDG).

Congenital disorders of glycosylation (CDG) are a large family of rare disorders affecting the different glycosylation pathways. Defective glycosylation can affect any organ, with varying symptoms among the different CDG. Even between individuals with the same CDG there is quite variable severity. Associating specific symptoms to deficiencies of certain glycoproteins or glycolipids is thus a challenging task. In this review, we focus on the glycosphingolipid (GSL) synthesis pathway, which is still rather unexplored in the context of CDG, and outline the functions of the main GSLs, including gangliosides, and their role in the central nervous system. We provide an overview of GSL studies that have been performed in CDG and show that abnormal GSL levels are not only observed in CDG directly affecting GSL synthesis, but also in better known CDG, such as PMM2-CDG. We highlight the importance of studying GSLs in CDG in order to better understand the pathophysiology of these disorders.

Human Cerebellum Gangliosides: A Comprehensive Analysis by Ion Mobility Tandem Mass Spectrometry.

The human cerebellum is an ultraspecialized region of the brain responsible for cognitive functions and movement coordination. The fine mechanisms through which the process of aging impacts such functions are not well understood; therefore, a rigorous exploration of this brain region at the molecular level is deemed necessary. Gangliosides, sialylated glycosphingolipids, highly and specifically expressed in the human central nervous system, represent possible molecular markers of cerebellum development and aging. In this context, for a comprehensive determination of development- and age-specific components, we have conducted here a comparative profiling and structural determination of the gangliosides expressed in fetal cerebellum in two intrauterine developmental stages and aged cerebellum by ion mobility separation (IMS) mass spectrometry (MS) and tandem MS (MS/MS). Due to the high sensitivity and efficiency of separation provided by IMS MS, no less than 551 chemically distinct species were identified, which represents 4.5 times more gangliosides than ever discovered in this brain region. The detailed assessment of fetal vs aged cerebellum gangliosidome showed marked discrepancies not only in the general number of the species expressed, but also in their sialylation patterns, the modifications of the glycan core, and the composition of the ceramides. All of these characteristics are potential markers of cerebellum development and aging. The structural analysis by collision-induced dissociation (CID) documented the occurrence of GD1b (d18:1/18:0) isomer in the fetal cerebellum in the second gestational trimester, with all probability of GQ1b (t18:1/18:0) in the near-term fetus and of GQ1b (d18:1/18:0) in aged cerebellum.

Synergistic Binding of SARS-CoV-2 to ACE2 and Gangliosides in Native Lipid Membranes.

Viruses utilize cell surface glycans and plasma membrane receptors to attain an adequate attachment strength for initiating cellular entry. We show that SARS-CoV-2 particles bind to endogenous ACE2 receptors and added sialylated gangliosides in near-native membranes. This was explored using supported membrane bilayers (SMBs) that were formed using plasma membrane vesicles having endogenous ACE2 and GD1a gangliosides reconstituted in lipid vesicles. The virus binding rate to the SMBs is influenced by GD1a and inhibition of the ganglioside reduces the extent of virus binding to the membrane receptors. Using combinations of inhibition assays, we confirm that added GD1a in lipid membranes increases the availability of the endogenous ACE2 receptor and results in the synergistic binding of SARS-CoV-2 to the membrane receptors in SMBs.

Newcastle disease virus activates diverse signaling pathways via Src to facilitate virus entry into host macrophages.

As an intrinsic cellular mechanism responsible for the internalization of extracellular ligands and membrane components, caveolae-mediated endocytosis (CavME) is also exploited by certain pathogens for endocytic entry [e.g., Newcastle disease virus (NDV) of paramyxovirus]. However, the molecular mechanisms of NDV-induced CavME remain poorly understood. Herein, we demonstrate that sialic acid-containing gangliosides, rather than glycoproteins, were utilized by NDV as receptors to initiate the endocytic entry of NDV into HD11 cells. The binding of NDV to gangliosides induced the activation of a non-receptor tyrosine kinase, Src, leading to the phosphorylation of caveolin-1 (Cav1) and dynamin-2 (Dyn2), which contributed to the endocytic entry of NDV. Moreover, an inoculation of cells with NDV-induced actin cytoskeletal rearrangement through Src to facilitate NDV entry via endocytosis and direct fusion with the plasma membrane. Subsequently, unique members of the Rho GTPases family, RhoA and Cdc42, were activated by NDV in a Src-dependent manner. Further analyses revealed that RhoA and Cdc42 regulated the activities of specific effectors, cofilin and myosin regulatory light chain 2, responsible for actin cytoskeleton rearrangement, through diverse intracellular signaling cascades. Taken together, our results suggest that an inoculation of NDV-induced Src-mediated cellular activation by binding to ganglioside receptors. This process orchestrated NDV endocytic entry by modulating the activities of caveolae-associated Cav1 and Dyn2, as well as specific Rho GTPases and downstream effectors. IMPORTANCE: In general, it is known that the paramyxovirus gains access to host cells through direct penetration at the plasma membrane; however, emerging evidence suggests more complex entry mechanisms for paramyxoviruses. The endocytic entry of Newcastle disease virus (NDV), a representative member of the paramyxovirus family, into multiple types of cells has been recently reported. Herein, we demonstrate the binding of NDV to induce ganglioside-activated Src signaling, which is responsible for the endocytic entry of NDV through caveolae-mediated endocytosis. This process involved Src-dependent activation of the caveolae-associated Cav1 and Dyn2, as well as specific Rho GTPase and downstream effectors, thereby orchestrating the endocytic entry process of NDV. Our findings uncover a novel molecular mechanism of endocytic entry of NDV into host cells and provide novel insight into paramyxovirus mechanisms of entry.

The pathophysiological role of endoneurial inflammatory edema in early classical Guillain-Barré syndrome.

The objective of this review was to analyze the pathophysiological role of endoneurial inflammatory edema in initial stages of classic Guillain-Barré syndrome (GBS), arbitrarily divided into very early GBS (≤ 4 days after symptom onset) and early GBS (≤ 10 days). Classic GBS, with variable degree of flaccid and areflexic tetraparesis, encompasses demyelinating and axonal forms. Initial autopsy studies in early GBS have demonstrated that endoneurial inflammatory edema of proximal nerve trunks, particularly spinal nerves, is the outstanding lesion. Variable permeability of the blood-nerve barrier dictates such lesion topography. In proximal nerve trunks possessing epi-perineurium, edema may increase the endoneurial fluid pressure causing ischemic changes. Critical analysis the first pathological description of the axonal form GBS shows a combination of axonal degeneration and demyelination in spinal roots, and pure Wallerian-like degeneration in peripheral nerve trunks. This case might be reclassified as demyelinating GBS with secondary axonal degeneration. Both in acute motor axonal neuropathy and acute motor-sensory axonal neuropathy, Wallerian-like degeneration of motor fibers predominates in the distal part of ventral spinal roots abutting the dura mater, another feature re-emphasizing the pathogenic relevance of this area. Electrophysiological and imaging studies also point to a predominant alteration at the spinal nerve level, which is a hotspot in any early GBS subtype. Serum biomarkers of axonal damage, including neurofilament light chain and peripherin, are increased in the great majority of patients with any early GBS subtype; endoneurial ischemia of proximal nerve trunks could contribute to such axonal damage. It is concluded that inflammatory edema of proximal nerve trunks is an essential pathogenic event in early GBS, which has a tangible impact for accurate approach to the disease.

Methodological Pitfalls of Investigating Lipid Rafts in the Brain: What Are We Still Missing?

The purpose of this review is to succinctly examine the methodologies used in lipid raft research in the brain and to highlight the drawbacks of some investigative approaches. Lipid rafts are biochemically and biophysically different from the bulk membrane. A specific lipid environment within membrane domains provides a harbor for distinct raftophilic proteins, all of which in concert create a specialized platform orchestrating various cellular processes. Studying lipid rafts has proved to be arduous due to their elusive nature, mobility, and constant dynamic reorganization to meet the cellular needs. Studying neuronal lipid rafts is particularly cumbersome due to the immensely complex regional molecular architecture of the central nervous system. Biochemical fractionation, performed with or without detergents, is still the most widely used method to isolate lipid rafts. However, the differences in solubilization when various detergents are used has exposed a dire need to find more reliable methods to study particular rafts. Biochemical methods need to be complemented with other approaches such as live-cell microscopy, imaging mass spectrometry, and the development of specific non-invasive fluorescent probes to obtain a more complete image of raft dynamics and to study the spatio-temporal expression of rafts in live cells.

Association of epilepsy and neurological impairments with homozygous recessive missense mutations found in the genes responsible for ganglioside biosynthesis (ST3GAL5) and calcium voltage-gated channels (CACNA1H) - insights through molecular dynamic simulations.

With over 2.2 million cases, the incidence rate of epilepsy in Pakistan is far higher than the rest of the world due primarily to the frequent, traditionally imposed cousin marriages. In the present study, comprehensive whole exome sequencing (WES) analyses of a three-generation family with four affected members presenting 'unexplained' childhood absence epilepsy (CAE), seizures and dementia, was performed in a quest to identify heritable, epilepsy-causal gene variants to better aid in carrier screening and genetic counselling. The WES data was generated, analyzed, and validated through Sanger's sequencing, molecular dynamic simulation (MDS) analysis, and molecular mechanics with generalized Born and surface area solvation (MM/GBSA) studies. Two homozygous recessive, missense mutations in ST3GAL5 (c.311A > G, p. His104Arg) and CACNA1H (c.6230G > A, p. Arg2077His) genes, earlier regarded as benign or of uncertain significance, have been identified as a potential etiology. Comparative MDS and free binding energy calculations revealed substantial structural perturbations in mutant forms of ST3GAL5 leading to decreased binding and reduced catalytic activity of the p.His104Arg and two other functional variants (p.Val74Glu and p.Arg288Ter) when compared with wild type. Our findings reinforce that WES analyses may uncover 'hidden', heritable variants and together with MDS and MM/GBSA may provide plausible clues to answer the unexplained causes of epilepsy for an effective management and better patient outcome. Further, revisit of epilepsy-associated mutational landscape in population context is imperative as the variants with 'benign' tags may turn out to be 'non-benign', when exist in combination with other benign.Communicated by Ramaswamy H. Sarma.

Establishment of a targeted analysis method for gangliosides in mouse tissues by HILIC-ESI-MS/MS.

Gangliosides play an imperative role in cell signaling, neuronal recovery, apoptosis, and other physiological processes. For example, GM3 can regulate hypothalamic leptin resistance and control energy homeostasis, GD3 can mediate cell proliferation and differentiation and induce apoptosis, and GQ1b can stimulate neurogenesis. Therefore, the present study sought to establish and optimize the targeted analysis method for ganglioside subclasses and their molecular species using hydrophilic interaction liquid chromatography-triple quadrupole-MS/MS (HILIC-QQQ-MS/MS). Additionally, the fragmentation pattern of different ganglioside subclasses and their retention time patterns were analyzed, providing more accurate qualitative results. The limit of quantitation (LOQ) was as low as 10-4 ng. Moreover, the molecular species of gangliosides in the liver, cortex, and hypothalamus of C57BL/6 mice were analyzed using the established method. A total of 23 ganglioside subclasses with 164 molecular species, including 40 O-acetylated ganglioside molecular species and 28 NeuGc ganglioside molecular species, were identified using the semi-quantitative analysis method of an external standard curve corrected by an internal standard. In addition to NeuGc gangliosides, the contents of ganglioside subclasses were more abundant in the mouse brain than those in the mouse liver; especially, the contents of unsaturated gangliosides in the hypothalamus were much higher than those in the liver. Among them, O-acetylated gangliosides were detected only in the cortex and hypothalamus at a concentration of up to 100 µg/mg protein (40 molecular species). Overall, the proposed method expanded the detectable number of ganglioside subclasses and molecular species in biological samples and provided more opportunities for further study of the biological functions of gangliosides.

Chemoenzymatic Synthesis of GAA-7 Glycan Analogues and Evaluation of Their Neuritogenic Activities.

Ganglioside GAA-7 exhibits higher neurite outgrowth than ganglioside GM1a and most echinodermatous gangliosides (EGs) when tested on neuron-like rat adrenal pheochromocytoma (PC12) cells in the presence of nerve growth factor (NGF). The unique structure of GAA-7 glycan, containing an uncommon sialic acid (8-O-methyl-N-glycolylneuraminic acid) and sialic acid-α-2,3-GalNAc linkage, makes it challenging to synthesize. We recently developed a streamlined method to chemoenzymatically synthesize GAA-7 glycan and employed this modular strategy to efficiently prepare a library of GAA-7 glycan analogues incorporating N-modified or 8-methoxyl sialic acids. Most of these synthetic glycans exhibited moderate efficacy in promoting neuronal differentiation of PC12 cells. Among them, the analogue containing common sialic acid shows greater potential than the GAA-7 glycan itself. This result reveals that methoxy modification is not essential for neurite outgrowth. Consequently, the readily available analogue presents a promising model for further biological investigations.

Trajectories of Human Milk Gangliosides during the First Four Hundred Days and Maternal-to-Offspring Transfer of Gangliosides: Results from a Chinese Cohort Study.

BACKGROUND: Gangliosides are crucial for early-life cognition and immunity development. However, limited data exist on gangliosides within the Chinese population, and maternal-to-fetal/infant ganglioside transport remains unclear. OBJECTIVES: This study aimed to investigate gangliosides concentrations and trajectories in Chinese human milk during the first 400 d of lactation, and seek to understand gangliosides transmission between mother and offspring. METHODS: This study involved 921 cross-sectional participants providing human milk samples across 0-400 d of lactation and 136 longitudinal participants offering maternal plasma, cord plasma, and human milk samples within the first 45 d postpartum. Ultrahigh-performance liquid chromatography-tandem mass spectrometry was used for the quantification of gangliosides. RESULTS: Human milk GM3 (Neu5Acα2-3Galß1-4GlcßCer) concentration increased from 2.29 ± 1.87 to 13.93 ± 4.82 µg/mL, whereas GD3 (Neu5Acα2-8Neu5Acα2-3Galß1-4GlcßCer) decreased from 17.94 ± 6.41 to 0.30 ± 0.50 µg/mL during the first 400 d postpartum (all P < 0.05). Consistent results were observed in cross-sectional and longitudinal participants. GD3 concentration gradually increased from maternal plasma (1.58 µg/mL) through cord plasma (2.05 µg/mL) to colostrum (21.35 µg/mL). Significant positive correlations were observed between maternal and cord plasma for both GM3 (r = 0.30, P < 0.001) and GD3 (r = 0.35, P < 0.001), and maternal plasma GD3 also correlated positively with colostrum concentrations (r = 0.21, P = 0.015). Additionally, in maternal and cord plasma, gangliosides were mainly linked with 16- and 18-carbon fatty acids. However, human milk GM3 showed a broad spectrum of fatty acid chain lengths, whereas GD3 was primarily tied to very long-chain fatty acids (≥20 carbon). CONCLUSIONS: We identified an increase in GM3 and a decrease in GD3 concentration in human milk, with GD3 notably more concentrated in cord plasma and colostrum. Importantly, ganglioside concentrations in maternal plasma positively correlated with those in cord plasma and colostrum. Our findings contribute to the existing Chinese data on gangliosides and enhance understanding of their transmission patterns from mother to offspring. This trial was registered at chictr.org.cn as ChiCTR1800015387.

Recent progress in the synthesis of glycosphingolipids.

To accelerate the biological study and application of the diverse functions of glycosphingolipids (GSLs), the production of structurally defined GSLs has been greatly demanded. In this review, we focus on the recent developments in the chemical and chemoenzymatic synthesis of GSLs. In the chemical synthesis section, the syntheses based on glucosyl ceramide cassette, late-stage sialylation, and diversity-oriented strategies for GSLs or ganglioside synthesis are highlighted, which delivered terpioside B, fluorescent sialyl lactotetraosyl ceramide, and analogs of lacto-ganglio-series GSLs, respectively. In the chemoenzymatic synthesis section, the synthesis of ganglioside GM1 by multistep one-pot multienzyme method and the total synthesis of highly complex ganglioside LLG-5 using a water-soluble lactosyl ceramide as a key substrate for enzymatic sialylation are described.

Reversible splenial lesion syndrome in patient with acute motor and sensory axonal neuropathy.

Even though the classical clinical concept supports the clear difference between diseases affecting the central and peripheral nervous systems, this difference is becoming less rigid. Here, we report the case of a 50-year-old male patient who presented with acroparaesthesia, headache, and flaccid tetraparesis after febrile diarrhea. Nerve conduction studies indicated action potentials with low amplitudes, which are typical in acute motor and sensory axonal neuropathy. Magnetic resonance revealed a round lesion in the splenium consistent with a diagnosis of reversible splenial lesion syndrome. A polyclonal antiganglioside antibody response was detected. The patient was successfully treated with intravenous immunoglobulins. The coexistence of reversible splenial lesion syndrome and acute motor and sensory axonal neuropathy has not been described in the literature so far. We discuss our diagnostic dilemmas and the possible role of antiganglioside antibodies in the occurrence of simultaneous lesions of the central and peripheral nervous systems.