Explore the vast range of titles available.

Parkinson disease (PD) is a chronic progressive neurodegenerative disorder leading to motor and non-motor impairment, often resulting in severe loss of quality of life. There are symptomatic treatments without effect on the progression of PD. A disease-modifying treatment that could ideally stop the neurodegenerative process is direly needed. Monosialotetrahexosylganglioside (GM1) is a promising molecule with neuroprotective effects in preclinical models of PD and has yielded encouraging results in patients with PD in a randomized placebo-controlled trial. Talineuren (TLN) is a liposomal formulation of GM1 that has been shown to cross the blood-brain barrier in animals. We assessed the safety and pharmacokinetics (PK) of TLN in patients with PD. We prospectively enrolled 12 patients with PD into a single-center, open-label phase I trial to assess the safety and tolerability of weekly infusions with TLN. The maximum suitable dose of TLN was determined by dose escalation in three patients. All three patients tolerated the predetermined maximal dose of 720 mg. Subsequently, these and nine additional patients received weekly infusions at the maximum suitable dose of 720 mg TLN over two months (1 patient stopped prematurely). PK were determined for the additional nine patients as a secondary outcome measure. Cmax was reached 4 h after infusion start for all but one participant, who reached Cmax after 1 h, while the median plasma half-life was reached at 12.6 h. All adverse events were continuously assessed as the primary objective and coded according to the Medical Dictionary for Regulatory Activities (MedDRA). Clinical manifestations of PD were assessed as secondary outcomes using the Movement Disorders Society Unified Parkinson's Disease Rating Scale (MDS-UPDRS), including a levodopa challenge test at baseline and end. In addition to weekly history taking, scales to measure mood, behavior, quality of life, sleepiness, non-motor symptoms of PD, and cognition were used as further secondary outcomes as well as assessing the Levodopa-Equivalent Daily Dose (LEDD). Overall, 304 adverse events (mean: 25.33; 6-75 events per patient) occurred, 267 of which were mild (mean: 22.25; 3-72 events per patient). 23 were considered related to the study treatment (0-8 events per patient). Very mild-to-severe acute infusion reactions at the second, third, or fourth administration of TLN within the first minutes of the infusion occurred in seven patients. All reported back or neck pain. Other acute infusion reactions were urticaria, plethora, nausea, and chest pain. These adverse reactions disappeared within minutes of stopping the infusion and did not recur when TLN administration was resumed at a very low rate. Beyond the fourth administration, infusions could be given at increased rates up to 370 ml/h, and no acute reaction occurred anymore. The mechanism of this acute infusion reaction remains unclear. Some patients reported mild dizziness for a few hours after TLN following many but not all administrations throughout the study. Non-motor symptoms of PD, motor parkinsonian signs off medication, and quality of life improved significantly during the treatment phase, including the MDS-UPDRS total score (mean decrease -11.09; 95% Confidence Interval [CI]; -18, -4.1; p = 0.006), the Parkinson's disease Questionnaire-39 (PDQ-39) summary index (mean decrease -2.91; 95% CI; -4.4, -1.4; p = 0.005), and the Non-Motor Symptoms Questionnaire (NMS-Quest) (mean decrease -4.27; 95% CI; -6.5, -2.1; p = 0.009). No statistically significant improvements were seen in the Montreal Cognitive Assessment (MoCA) (mean decrease -0.73; 95% CI; -2.1, 0.62; p = 0.255), Epworth Sleepiness Scale (mean increase 0.09; 95% CI; -2.6, 2.8; p > 0.999), Beck Depression Inventory (BDI) (mean decrease -1.27; 95% CI; -3.8, 1.3; p = 0.257), and the Starkstein Apathy Scale (mean increase 0.36; 95% CI; -1.6, 2.4; p = 0.822). Dopaminergic medications remained stable during the study (LEDD mean increase 8.18; 95% CI; -7.7, 24; p = 0.423). While clinical improvements indicate a benefit associated with TLN treatment, the trial design does not allow for definite conclusions regarding efficacy. A randomized, placebo-controlled trial will be required to corroborate our exploratory findings. TLN is safe and well-tolerated in general. This prospective phase I trial revealed non-allergic habituating acute infusion reactions at the second, third, or fourth treatment that can be prevented by a slower rate of infusion. Importantly, the exploratory results suggest a consistent improvement of signs and symptoms of PD. The NEON trial is registered at the US National Institutes of Health (ClinicalTrials.gov) #NCT04976127 and in the Swiss National Clinical Trials Portal (SNCTP000004631).

NRC publication: Yes

The interaction between HIV and dendritic cells (DCs) is an important early event in HIV-1 pathogenesis that leads to efficient viral dissemination. Here we demonstrate a HIV gp120-independent DC capture mechanism that uses virion-incorporated host-derived gangliosides with terminal α2–3-linked sialic acid linkages. Using exogenously enriched virus and artificial liposome particles, we demonstrate that both α2–3 gangliosides GM1 and GM3 are capable of mediating this interaction when present in the particle at high levels. In the absence of overexpression, GM3 is the primary ligand responsible for this capture mechanism, because siRNA depletion of GM3 but not GM1 from the producer cell and hence virions, resulted in a dramatic decrease in DC capture. Furthermore, HIV-1 capture by DCs was competitively inhibited by targeting virion-associated GM3, but was unchanged by targeting GM1. Finally, virions were derived from monocytoid THP-1 cells that constitutively display low levels of GM1 and GM3, or from THP-1 cells induced to express high surface levels of GM1 and GM3 upon stimulation with the TLR2/1 ligand Pam3CSK4. Compared with untreated THP-1 cells, virus produced from Pam3CSK4-stimulated THP-1 cells incorporated higher levels of GM3, but not GM1, and showed enhanced DC capture and trans-infection. Our results identify a unique HIV-1 DC attachment mechanism that is dependent on a host-cell–derived ligand, GM3, and is a unique example of pathogen mimicry of host-cell recognition pathways that drive virus capture and dissemination in vivo.

The ganglioside GM1 is present in neuronal membranes at elevated concentrations with an asymmetric spatial distribution. It is known to generate curvature and can be expected to strongly influence the neuron morphology. To elucidate these effects, we prepared giant vesicles with GM1 predominantly present in one leaflet of the membrane, mimicking the asymmetric GM1 distribution in neuronal membranes. Based on pulling inward and outward tubes, we developed a technique that allowed the direct measurement of the membrane spontaneous curvature. Using vesicle electroporation and fluorescence intensity analysis, we were able to quantify the GM1 asymmetry across the membrane and to subsequently estimate the local curvature generated by the molecule in the bilayer. Molecular-dynamics simulations confirm the experimentally determined dependence of the membrane spontaneous curvature as a function of GM1 asymmetry. GM1 plays a crucial role in connection with receptor proteins. Our results on curvature generation of GM1 point to an additional important role of this ganglioside, namely in shaping neuronal membranes.

Introduction Mucopolysaccharidosis type II (Hunter syndrome) is an X-linked recessive disorder caused by iduronate-2-sulfatase deficiency, affecting mainly male patients. The lack of its enzyme activity causes the accumulation of the glycosaminoglycans heparan sulfate and dermatan sulfate in all body tissues and leads to a secondary accumulation of gangliosides and ceramides. Objective and methods We conducted a lipidomic study to investigate the dysregulation of lipid pathways in neuronopathic MPS type II. A modified liquid extraction was performed for untargeted lipid analysis. A reverse phase ultraperformance liquid chromatography coupled to quadrupole time-of-flight (UPLC-QTOF) mass spectrometry allowed the identification of upregulated ganglioside and ceramide biomarkers in the plasma and urine of a MPS II patient group compared to a healthy control group. Results The altered pathways, including those related to glycerophospholipid metabolism and fatty acid oxidation, highlight the essential role of lipid metabolism in the progression of the disease. Conclusion The accumulation of gangliosides and ceramides could be associated with the neuropathology in various lysosomal storage diseases including MPS II.

The cancer stem cells (CSCs) of glioblastoma multiforme (GBM), a grade IV astrocytoma, have been enriched by the expressed marker CD133. However, recent studies have shown that CD133⁻ cells also possess tumor-initiating potential. By analysis of gangliosides on various cells, we show that ganglioside D3 (GD3) is overexpressed on eight neurospheres and tumor cells; in combination with CD133, the sorted cells exhibit a higher expression of stemness genes and self-renewal potential; and as few as six cells will form neurospheres and 20–30 cells will grow tumor in mice. Furthermore, GD3 synthase (GD3S) is increased in neurospheres and human GBM tissues, but not in normal brain tissues, and suppression of GD3S results in decreased GBM stem cell (GSC)-associated properties. In addition, a GD3 antibody is shown to induce complement-dependent cytotoxicity against cells expressing GD3 and inhibition of GBM tumor growth in vivo. Our results demonstrate that GD3 and GD3S are highly expressed in GSCs, play a key role in glioblastoma tumorigenicity, and are potential therapeutic targets against GBM.

For the MHC, MR1 and CD1 systems, antigen recognition involves contact of the membrane distal surfaces of both the αβ T cell receptor (TCR) and the antigen-presenting molecule. Whether other antigen display mechanisms by antigen-presenting molecules operate remains unknown. Here, we report mass spectrometry analyses of endogenous lipids captured by CD1c when bound to an autoreactive αβ TCR. CD1c binds twenty-six lipid species with bulky headgroups that cannot fit within the tight TCR-CD1c interface. We determined the crystal structures of CD1c presenting several gangliosides, revealing a general mechanism whereby two lipids, rather than one, are bound in the CD1c cleft. Bulky lipids are oriented sideways so that their polar headgroups protrude laterally through a side portal of the CD1c molecule - an evolutionarily conserved structural feature. The sideways-presented ganglioside headgroups do not hinder TCR binding and so represent a mechanism that allows autoreactive TCR recognition of CD1c. In addition, ex vivo studies showed that the sideways-presented gangliosides can also represent TCR recognition determinants. These findings reveal that CD1c simultaneously presents two lipid antigens from the top and side of its cleft, a general mechanism that differs markedly from other antigen-presenting molecules. Despite extensive structural studies elucidating how antigens are anchored to antigen-presenting molecules and presented to T cells, little is known about the display mechanism of the lipid-antigen-presenting molecule CD1c. Here, by combining structural immunology, lipidomics, and biophysical analysis, the authors reveal that the CD1c binding cleft accommodates two different lipids, one of them with a bulky headgroup positioned sideways for display to T cells, rather than upwards, different from the conventional upright antigen-presentation mode

Molecular mimicry between Campylobacter jejuni lipo-oligosaccharides (LOSs) and human gangliosides GM1 and GD1a induces the production of anti-GM1 and anti-GD1a antibodies, and the development of Guillain-Barré syndrome. Complexes of two different gangliosides form new molecular shapes capable of enhancing recognition by anti-ganglioside antibodies. To test the hypothesis that the complex of GM1-like and GD1a-like LOSs of C. jejuni induces the development of anti-GM1b antibodies in Guillain-Barré syndrome patients. Mass spectrometry analysis determined the LOS outer core structures, with which mice were immunized. IgG antibodies to single gangliosides and complex of gangliosides were tested in sera from Guillain-Barré syndrome patients from whom C. jejuni LOS had been isolated. Two isolates from GBS patients who had anti-GM1b antibodies, but neither anti-GM1 nor -GD1a antibodies, expressed both GM1-like and GD1a-like LOSs, but not GM1b-like LOS. Anti-GM1b antibodies were induced in one of the mice immunized with the C. jejuni bearing GM1-like and GD1a-like LOS. Sera from 20 patients had antibodies to the complex of GM1 and GD1a, all of which carried anti-GM1b reactivity. Five of these sera harbored neither anti-GM1 nor anti-GD1a antibodies. IgG antibodies to the complex were absorbed by GM1b, but by neither GM1 nor GD1a. GM1-like and GD1a-like LOSs form a GM1b epitope, inducing the development of anti-GM1b antibodies in patients with Guillain-Barré syndrome subsequent to C. jejuni enteritis. Here, we present a new paradigm that the complex of two different structures forms a new molecular mimicry, inducing the production of autoantibodies.

While various glycosphingolipids were identified as cancer‐associated carbohydrate antigens to be used as tumor markers, disialylated gangliosides such as GD3 and GD2 have particularly attracted attention from many researchers as promising cancer‐associated antigens. Simultaneously, their functions in cancer and normal tissues have also been reported. Although GD3 is expressed at the early neural developmental stage and in various cancers, it is also found in the activated status of some normal cells such as astrocytes and lymphocytes. On the other hand, GD2 is expressed in more restricted cells than GD3, enabling anti‐GD2 immune therapy to be more applicable for immunotherapy. Recently, the expression of GD2 has been reported in various epithelial cancers and neuroectoderm‐derived tumors. The involvement of GD2 in cancer stem cell propertiesand the roles of GD2 in the signal modulation to bring about cancer stemness are now some of the most fascinating research topics. Cancer immunotherapy targeting GD2 by anti‐GD2 antibody or anti‐GD2 CAR‐T is now widely being challenged with various modifications such as combination with cytokines, chemotherapy, or immune checkpoint blocking. Among cancer‐associated antigens, ganglioside GD2 is the most crucial and essential carbohydrate antigen as a modulator of malignant signals and as a target of immunotherapy for refractory cancers. In particular, GD2 is now believed to be a marker of cancer stem cells and to be essentially involved in the features of cancer stemness.

SeviL is a recently isolated lectin found to bind to the linear saccharides of the ganglioside GM1b (Neu5Ac α (2-3)Gal β (1-3)GalNAc β (1-4)Gal β (1-4)Glc) and its precursor, asialo-GM1 (Gal β (1-3)GalNAc β (1-4)Gal β (1-4)Glc). The crystal structures of recombinant SeviL have been determined in the presence and absence of ligand. The protein belongs to the β -trefoil family, but shows only weak sequence similarity to known structures. SeviL forms a dimer in solution, with one binding site per subunit, close to the subunit interface. Molecular details of glycan recognition by SeviL in solution were analysed by ligand- and protein-based NMR techniques as well as ligand binding assays. SeviL shows no interaction with GM1 due to steric hindrance with the sialic acid branch that is absent from GM1b. This unusual specificity makes SeviL of great interest for the detection and control of certain cancer cells, and cells of the immune system, that display asialo-GM1.