The role of gangliosides in neurodevelopment

Lipids in human milk

Fat is the main energy providing component in human milk and comprising a complex mixture of different lipid species, with quantitative dominance of triglycerides. After elucidating the fatty acid composition, more recent research has looked at influencing factors and the importance of specific lipids. Here we review quantitative aspects of maternal metabolism which contribute to the milk fatty acid composition, especially considering essential fatty acids and their long chain polyunsaturated derivatives. In this context studies with stable isotopes have indicated the importance of maternal body pools for mediating the effects of diet on milk composition. Furthermore, the importance of positioning of palmitic acid at the glycerol backbone of triglycerides is discussed, and the phospholipids of the milk fat globule membrane are described and examples for their potential importance for infant development are presented.

Ion mobility mass spectrometry provides novel insights into the expression and structure of gangliosides in the normal adult human hippocampus

General work-flow for ganglioside analysis by IM-MS.

The CLIMB (Complex Lipids In Mothers and Babies) study: protocol for a multicentre, three-group, parallel randomised controlled trial to investigate the effect of supplementation of complex lipids in pregnancy, on maternal ganglioside status and subsequent cognitive outcomes in the offspring

INTRODUCTION

Complex lipids are important constituents of the central nervous system. Studies have shown that supplementation with complex milk lipids (CML) in pregnancy may increase the level of fetal gangliosides (GA), with the potential to improve cognitive outcomes.

METHODS AND ANALYSIS

We aim to recruit approximately 1500 pregnant women in the first trimester (11-14 weeks) and randomise them into one of the three treatment groups: standard maternal milk formulation, CML-enhanced maternal milk formulation or no maternal milk intervention with standard pregnancy advice (ie, the standard care). Maternal lifestyle and demographic data will be collected throughout the pregnancy, as well as biological samples (eg, blood, hair, urine, buccal smear, cord blood, cord and placenta samples). Data from standard obstetric care recorded in hospital maternity notes (eg, ultrasound reports, results of oral glucose tolerance test and pregnancy outcome data) will also be extracted. Postnatal follow-up will be at 6 weeks and 12 months of age, at which point infant cognitive development will be assessed (Bayley Scales of Infant Development I).

ETHICS AND DISSEMINATION

This project was approved by the Ethics Committee of Chongqing Medical University. Dissemination of findings will take the form of publications in peer-reviewed journals and presentations at national and international conferences.

TRIAL REGISTRATION NUMBER

ChiCTR-IOR-16007700; Pre-results.

Adjuvant treatment with monosialoganglioside may improve neurological outcomes in neonatal hypoxic-ischemic encephalopathy: A meta-analysis of randomized controlled trials

Background

Ganglioside has a neuroprotective role in neonatal hypoxic–ischemic encephalopathy (HIE). This study aimed to evaluate the neurological outcomes of monosialoganglioside as adjuvant treatment for neonatal HIE by conducting a meta-analysis.

Methods

A comprehensive literature search was made in the Pubmed, EMBASE, Cochrane Library, Wanfang, CNKI, VIP databases through October 2016. Randomized controlled trials comparing monosialoganglioside with the usual treatment for newborns having HIE deemed eligible. Weighted mean difference (WMD) and risk ratio (RR) with 95% confidence interval (CI) were calculated for continuous and dichotomous data, respectively.

Results

Ten trials consisting of 787 neonates were included. Adjuvant treatment with monosialoganglioside significantly reduced major neurodevelopmental disabilities (RR = 0.35; 95% CI = 0.21–0.57), cerebral palsy (RR = 0.32; 95% CI = 0.12–0.87), mental retardation (RR = 0.31; 95% CI = 0.11–0.88) as well as improved the mental (WMD = 14.95; 95% CI = 7.44–22.46) and psychomotive (WMD = 13.40; 95% CI = 6.69–20.11) development index during the follow-up. Also, monosialoganglioside significantly improved Neonatal Behavioral Neurological Assessment scores (WMD = 2.91; 95% CI = 2.05–3.78) compared with the usual treatment. However, adverse effects associated with monosialoganglioside were poorly reported in the included trials.

Conclusion

Adjuvant treatment with monosialoganglioside had beneficial effects in improving neurological outcomes in neonatal HIE. However, these findings should be interpreted with caution because of methodological flaws in the included trials. Furthermore, safety of monosialoganglioside use should also be further evaluated.

Benefits of Lactoferrin, Osteopontin and Milk Fat Globule Membranes for Infants

The provision of essential and non-essential amino acids for breast-fed infants is the major function of milk proteins. In addition, breast-fed infants might benefit from bioactivities of milk proteins, which are exhibited in the intestine during the digestive phase and by absorption of intact proteins or derived peptides. For lactoferrin, osteopontin and milk fat globule membrane proteins/lipids, which have not until recently been included in substantial amounts in infant formulas, in vitro experiments and animal models provide a convincing base of evidence for bioactivities, which contribute to the protection of the infant from pathogens, improve nutrient absorption, support the development of the immune system and provide components for optimal neurodevelopment. Technologies have become available to obtain these compounds from cow´s milk and the bovine compounds also exhibit bioactivities in humans. Randomized clinical trials with experimental infant formulas incorporating lactoferrin, osteopontin, or milk fat globule membranes have already provided some evidence for clinical benefits. This review aims to compare findings from laboratory and animal experiments with outcomes of clinical studies. There is good justification from basic science and there are promising results from clinical studies for beneficial effects of lactoferrin, osteopontin and the milk fat globule membrane complex of proteins and lipids. Further studies should ideally be adequately powered to investigate effects on clinically relevant endpoints in healthy term infants.

Inhibition of β-Glucocerebrosidase Activity Preserves Motor Unit Integrity in a Mouse Model of Amyotrophic Lateral Sclerosis

Recent metabolomic reports connect dysregulation of glycosphingolipids, particularly ceramide and glucosylceramide, to neurodegeneration and to motor unit dismantling in amyotrophic lateral sclerosis at late disease stage. We report here altered levels of gangliosides in the cerebrospinal fluid of amyotrophic lateral sclerosis patients in early disease stage. Conduritol B epoxide is an inhibitor of acid beta-glucosidase, and lowers glucosylceramide degradation. Glucosylceramide is the precursor for all of the more complex glycosphingolipids. In SOD1G86R mice, an animal model of amyotrophic lateral sclerosis, conduritol B epoxide preserved ganglioside distribution at the neuromuscular junction, delayed disease onset, improved motor function and preserved motor neurons as well as neuromuscular junctions from degeneration. Conduritol B epoxide mitigated gene dysregulation in the spinal cord and restored the expression of genes involved in signal transduction and axonal elongation. Inhibition of acid beta-glucosidase promoted faster axonal elongation in an in vitro model of neuromuscular junctions and hastened recovery after peripheral nerve injury in wild type mice. Here, we provide evidence that glycosphingolipids play an important role in muscle innervation, which degenerates in amyotrophic lateral sclerosis from the early disease stage. This is a first proof of concept study showing that modulating the catabolism of glucosylceramide may be a therapeutic target for this devastating disease.

Neuraminidases 3 and 4 regulate neuronal function by catabolizing brain gangliosides

Gangliosides (sialylated glycolipids) play an essential role in the CNS by regulating recognition and signaling in neurons. Metabolic blocks in processing and catabolism of gangliosides result in the development of severe neurologic disorders, including gangliosidoses manifesting with neurodegeneration and neuroinflammation. We demonstrate that 2 mammalian enzymes, neuraminidases 3 and 4, play important roles in catabolic processing of brain gangliosides by cleaving terminal sialic acid residues in their glycan chains. In neuraminidase 3 and 4 double-knockout mice, G_M3 ganglioside is stored in microglia, vascular pericytes, and neurons, causing micro- and astrogliosis, neuroinflammation, accumulation of lipofuscin bodies, and memory loss, whereas their cortical and hippocampal neurons have lower rate of neuritogenesis in vitro Double-knockout mice also have reduced levels of G_M1 ganglioside and myelin in neuronal axons. Furthermore, neuraminidase 3 deficiency drastically increased storage of G_M2 in the brain tissues of an asymptomatic mouse model of Tay-Sachs disease, a severe human gangliosidosis, indicating that this enzyme is responsible for the metabolic bypass of β-hexosaminidase A deficiency. Together, our results provide the first in vivo evidence that neuraminidases 3 and 4 have important roles in CNS function by catabolizing gangliosides and preventing their storage in lipofuscin bodies.-Pan, X., De Britto Pará De Aragão, C., Velasco-Martin, J. P., Priestman, D. A., Wu, H. Y., Takahashi, K., Yamaguchi, K., Sturiale, L., Garozzo, D., Platt, F. M., Lamarche-Vane, N., Morales, C. R., Miyagi, T., Pshezhetsky, A. V. Neuraminidases 3 and 4 regulate neuronal function by catabolizing brain gangliosides.

Supplementation of Infant Formula with Bovine Milk Fat Globule Membranes

Studies have shown that supplementation of infant formula with bovine milk fat globule membranes (MFGMs) may substantially narrow the gap in health outcomes between formula-fed and breastfed infants. In one study, consumption of a formula supplemented with a lipid-rich MFGM concentrate between 2 and 6 mo of age improved cognitive performance at 24 wk of age. In another study, a formula supplemented with a protein-rich MFGM concentrate given between 2 and 6 mo of age improved cognitive performance at 12 mo of age, decreased infectious morbidity until 6 mo of age, and yielded serum cholesterol concentrations closer to those of breastfed infants. A third study that assessed the safety of supplementing infant formula with a lipid-rich or a protein-rich MFGM concentrate found a noninferior weight gain for both groups compared with a nonsupplemented formula. In this study, there was an increased risk of eczema in the protein-rich group, but no serious adverse events. Infant formulas with supplemental MFGMs have been launched on the market in several countries. However, the evidence base must still be considered quite limited. Based on 3 randomized controlled trials that are not comparable, the intervention seems safe, but there is not enough evidence for a general recommendation on which MFGM fraction to use and at what concentration as formula supplement for a given outcome.

Molecular mechanisms involved in dendritic cell dysfunction in cancer

Dendritic cells (DC) play a pivotal role in the tumor microenvironment (TME). As the primary antigen-presenting cells in the tumor, DCs modulate anti-tumor responses by regulating the magnitude and duration of infiltrating cytotoxic T lymphocyte responses. Unfortunately, due to the immunosuppressive nature of the TME, as well as the inherent plasticity of DCs, tumor DCs are often dysfunctional, a phenomenon that contributes to immune evasion. Recent progresses in our understanding of tumor DC biology have revealed potential molecular targets that allow us to improve tumor DC immunogenicity and cancer immunotherapy. Here, we review the molecular mechanisms that drive tumor DC dysfunction. We discuss recent advances in our understanding of tumor DC ontogeny, tumor DC subset heterogeneity, and factors in the tumor microenvironment that affect DC recruitment, differentiation, and function. Finally, we describe potential strategies to optimize tumor DC function in the context of cancer therapy.

Sustainable Nanosystem Development for Mass Spectrometry

Nowadays, considerable efforts are invested into development of sustainable nanosystems as front end technology for either Electrospray Ionization (ESI) or Matrix-Assisted Laser Desorption/Ionization (MALDI) mass spectrometry (MS). Since their first introduction in MS, nanofluidics demonstrated a high potential to discover novel biopolymer species. These systems confirmed the unique ability to offer structural elucidation of molecular species, which often represent valuable biomarkers of severe diseases. In view of these major advantages of nanofluidics-MS, this chapter reviews the strategies, which allowed a successful development of nanotechnology for MS and the applications in biological and clinical research. The first part will be dedicated to the principles and technical developments of advanced nanosystems for electrospray and MALDI MS. The second part will highlight the most important applications in clinical proteomics and glycomics. Finally, this chapter will emphasize that advanced nanosystems-MS has real perspectives to become a routine method for early diagnosis of severe pathologies.

New Insights on Non-Enzymatic Oxidation of Ganglioside GM1 Using Mass Spectrometry

Gangliosides are acidic glycosphingolipids that are present in cell membranes and lipid raft domains, being particularly abundant in central nervous systems. They participate in modulating cell membrane properties, cell-cell recognition, cell regulation, and signaling. Disturbance in ganglioside metabolism has been correlated with the development of diseases, such as neurodegenerative diseases, and in inflammation. Both conditions are associated with an increased production of reactive oxidation species (ROS) that can induce changes in the structure of biomolecules, including lipids, leading to the loss or modification of their function. Oxidized phospholipids are usually involved in chronic diseases and inflammation. However, knowledge regarding oxidation of gangliosides is scarce. In order to evaluate the effect of ROS in gangliosides, an in vitro biomimetic model system was used to study the susceptibility of GM1 (Neu5Acα2-3(Galβ1-3GalNAcβ1-4)Galβ1-4Glcβ1Cer) to undergo oxidative modifications. Oxidation of GM1 under Fenton reaction conditions was monitored using high resolution electrospray ionization-mass spectrometry (ESI-MS) and tandem mass spectrometry (ESI-MS/MS). Upon oxidation, GM1 underwent oxidative cleavages in the carbohydrate chain, leading to the formation of other gangliosides GM2 (GalNAcβ1-4Gal(Neu5Acα2-3)1-4Glcβ1Cer), GM3 (Neu5Acα2-3Galβ1-4Glcβ1Cer), asialo-GM1 (Galβ1-3GalNAcβ1-4Galβ1-4Glcβ1Cer), asialo-GM2 (GalNAcβ1-4Galβ1-4Glcβ1Cer), of the small glycolipids lactosylceramide (LacCer), glucosylceramide (GlcCer), and of ceramide (Cer). In addition, oxygenated GM1 and GM2 (as keto and hydroxy derivatives), glycans, oxidized glycans, and oxidized ceramides were also identified. Nonenzymatic oxidation of GM1 under oxidative stress contributes to the generation of other gangliosides that may participate in the imbalance of gangliosides metabolism in vivo, through uncontrolled enzymatic pathways and, consequently, play some role in neurodegenerative processes. Graphical Abstract ᅟ.

Animal models of GM2 gangliosidosis: utility and limitations

GM2 gangliosidosis, a subset of lysosomal storage disorders, is caused by a deficiency of the glycohydrolase, β-N-acetylhexosaminidase, and includes the closely related Tay–Sachs and Sandhoff diseases. The enzyme deficiency prevents the normal, stepwise degradation of ganglioside, which accumulates unchecked within the cellular lysosome, particularly in neurons. As a result, individuals with GM2 gangliosidosis experience progressive neurological diseases including motor deficits, progressive weakness and hypotonia, decreased responsiveness, vision deterioration, and seizures. Mice and cats are well-established animal models for Sandhoff disease, whereas Jacob sheep are the only known laboratory animal model of Tay–Sachs disease to exhibit clinical symptoms. Since the human diseases are relatively rare, animal models are indispensable tools for further study of pathogenesis and for development of potential treatments. Though no effective treatments for gangliosidoses currently exist, animal models have been used to test promising experimental therapies. Herein, the utility and limitations of gangliosidosis animal models and how they have contributed to the development of potential new treatments are described.

Tumor-derived factors modulating dendritic cell function

Dendritic cells (DC) play unique and diverse roles in the tumor occurrence, development, progression and response to therapy. First of all, DC can actively uptake tumor-associated antigens, process them and present antigenic peptides to T cells inducing and maintaining tumor-specific T cell responses. DC interaction with different immune effector cells may also support innate antitumor immunity, as well as humoral responses also known to inhibit tumor development in certain cases. On the other hand, DC are recruited to the tumor site by specific tumor-derived and stroma-derived factors, which may also impair DC maturation, differentiation and function, thus resulting in the deficient formation of antitumor immune response or development of DC-mediated tolerance and immune suppression. Identification of DC-stimulating and DC-suppressing/polarizing factors in the tumor environment and the mechanism of DC modulation are important for designing effective DC-based vaccines and for recovery of immunodeficient resident DC responsible for maintenance of clinically relevant antitumor immunity in patients with cancer. DC-targeting tumor-derived factors and their effects on resident and administered DC in the tumor milieu are described and discussed in this review.

A Postnatal Diet Containing Phospholipids, Processed to Yield Large, Phospholipid-Coated Lipid Droplets, Affects Specific Cognitive Behaviors in Healthy Male Mice

BACKGROUND

Infant cognitive development can be positively influenced by breastfeeding rather than formula feeding. The composition of breast milk, especially lipid quality, and the duration of breastfeeding have been linked to this effect.

OBJECTIVE

We investigated whether the physical properties and composition of lipid droplets in milk may contribute to cognitive development.

METHODS

From postnatal day (P) 16 to P44, healthy male C57BL/6JOlaHsd mice were fed either a control or a concept rodent diet, in which the dietary lipid droplets were large and coated with milk phospholipids, resembling more closely the physical properties and composition of breast milk lipids. Thereafter, all mice were fed an AIN-93M semisynthetic rodent diet. The mice were subjected to various cognitive tests during adolescence (P35-P44) and adulthood (P70-P101). On P102, mice were killed and brain phospholipids were analyzed.

RESULTS

The concept diet improved performance in short-term memory tasks that rely on novelty exploration during adolescence (T-maze; spontaneous alternation 87% in concept-fed mice compared with 74% in mice fed control diet; P < 0.05) and adulthood (novel object recognition; preference index 0.48 in concept-fed mice compared with 0.05 in control-fed mice; P < 0.05). Cognitive performance in long-term memory tasks, however, was unaffected by diet. Brain phospholipid composition at P102 was not different between diet groups.

CONCLUSIONS

Exposure to a diet with lipids mimicking more closely the structure and composition of lipids in breast milk improved specific cognitive behaviors in mice. These data suggest that lipid structure should be considered as a relevant target to improve dietary lipid quality in infant milk formulas.

Clinical Benefits of Milk Fat Globule Membranes for Infants and Children

The milk fat globule membrane (MFGM) in breast milk contains many bioactive components. Infant formulas traditionally have been devoid of the MFGM fraction, but dairy technology now has made the addition of bovine MFGM technically feasible. We identified 6 double-blinded randomized controlled trials exploring the effects of MFGM supplementation on the diets of infants or children. Results suggest that supplementation is safe and indicate positive effects on both neurodevelopment and defense against infections. MFGM supplementation of infant formula may narrow the gap in cognitive performance and infection rates between breastfed and formula-fed infants. Because of the small number of studies and the heterogeneity of interventions, more high-quality double-blinded randomized controlled trials are needed, with well characterized and clearly defined MFGM fractions, before firm conclusions on the effects of MFGM supplementation on the health and development of infants can be drawn.

Single molecule experiments emphasize GM1 as a key player of the different cytotoxicity of structurally distinct Aβ1-42 oligomers

It is well established that cytotoxic Aβ oligomers are the key factor that triggers the initial tissue and cell modifications eventually culminating in the development of Alzheimer's disease. Aβ1-42 oligomers display a high degree of polymorphism, and several structurally different oligomers have been described. Amongst them, two types, recently classified as A+ and A-, have been shown to possess similar size but distinct toxic properties, as a consequence of their biophysical and structural differences. Here, we have investigated by means of single molecule tracking the oligomer mobility on the plasma membrane of living neuroblastoma cells and the interaction with the ganglioside GM1, a component of membrane rafts. We have found that A+ and A- oligomers display a similar lateral diffusion on the plasma membrane of living cells. However, only the toxic A+ oligomers appear to interact and alter the mobility of GM1. We have also studied the lateral diffusion of each kind of oligomers in cells depleted or enriched in GM1. We found that the content of GM1 influences the diffusion of both types of oligomer, although the effect of the increased levels of GM1 is higher for the A+ type. Interestingly, the content of GM1 also affects significantly the mobility of GM1 molecules themselves.