Pathological α-syn aggregation is mediated by glycosphingolipid chain length and the physiological state of α-syn in vivo

2021 ◽  
Vol 118 (50) ◽  
pp. e2108489118
Author(s):  
Kristina Fredriksen ◽  
Stefanos Aivazidis ◽  
Karan Sharma ◽  
Kevin J. Burbidge ◽  
Caleb Pitcairn ◽  
...  
Keyword(s):  
Phenotypic Variability ◽  
Physiological State ◽  
Selective Reduction ◽  
Lewy Body Dementia ◽  
Neurological Dysfunction ◽  
Lysosomal Storage ◽  
Adult Mice ◽  
Specific Accumulation ◽  
Long Chain

GBA1 mutations that encode lysosomal β-glucocerebrosidase (GCase) cause the lysosomal storage disorder Gaucher disease (GD) and are strong risk factors for synucleinopathies, including Parkinson’s disease and Lewy body dementia. Only a subset of subjects with GBA1 mutations exhibit neurodegeneration, and the factors that influence neurological phenotypes are unknown. We find that α-synuclein (α-syn) neuropathology induced by GCase depletion depends on neuronal maturity, the physiological state of α-syn, and specific accumulation of long-chain glycosphingolipid (GSL) GCase substrates. Reduced GCase activity does not initiate α-syn aggregation in neonatal mice or immature human midbrain cultures; however, adult mice or mature midbrain cultures that express physiological α-syn oligomers are aggregation prone. Accumulation of long-chain GSLs (≥C22), but not short-chain species, induced α-syn pathology and neurological dysfunction. Selective reduction of long-chain GSLs ameliorated α-syn pathology through lysosomal cathepsins. We identify specific requirements that dictate synuclein pathology in GD models, providing possible explanations for the phenotypic variability in subjects with GCase deficiency.

Leptin inhibits basal but not gonadotrophin-stimulated testosterone production in the immature mouse and sheep testis

2008 ◽  
Vol 20 (4) ◽  
pp. 519 ◽  
Author(s):  
Muren Herrid ◽  
Yin Xia ◽  
Tim O'Shea ◽  
James R. McFarlane
Keyword(s):  
Leydig Cell ◽  
Developmental Stages ◽  
Physiological State ◽  
Inhibitory Effect ◽  
Slice Culture ◽  
Testosterone Production ◽  
Adult Mice ◽  
High Concentrations

The mechanisms whereby leptin regulates testosterone secretion are complex and are likely to involve actions at different levels of the hypothalamus–pituitary–gonadal axis. In the present study, the effect of leptin on testicular steroidogenesis at different developmental stages in mice and sheep was investigated. Testosterone data from testicular slice and Leydig cells of immature and adult mice testes demonstrated that the action of leptin in the regulation of steroidogenesis appears to be dependent on the developmental stage of the testis. Leptin biphasically modulates basal testosterone production in immature testicular slice cultures: at relatively low concentrations (6.25–12.5 ng mL–1) leptin exerts a significant inhibitory effect, but has less of an effect at very low (1.25 ng mL–1) or high concentrations (25 ng mL–1). However, leptin failed to modulate basal testosterone levels in Leydig cell preparations. In contrast with immature testes, leptin was unable to regulate either basal or human chorionic gonadotrophin (10 IU mL–1)-stimulated testosterone production in adult testicular slices or Leydig cell cultures. The age- and concentration-dependent regulation pattern was confirmed using sheep testicular slice culture. Leptin (1.56–25 ng mL–1) significantly inhibited basal testosterone production in the testis from birth to Day 21, but had no effect on Day 27 or older testes. However, the plasma and testicular concentrations of leptin and testosterone data in the ram indicate that such a regulatory effect of leptin on testis steroidogenesis in vitro is unable to efficiently influence testosterone concentrations in vivo. This does not exclude the possibility of a non-competitive mechanism of interaction between leptin and luteinising hormone to regulate testosterone production. Thus, we hypothesise that leptin is not an important independent regulator of testosterone concentration in the normal physiological state. The physiological significance and mechanism of leptin regulation of basal testosterone production are not known; further studies are required to elucidate these important issues.

scholarly journals Glucose Oligosaccharide and Long-Chain Glucomannan Feed Additives Induce Enhanced Activation of Intraepithelial NK Cells and Relative Abundance of Commensal Lactic Acid Bacteria in Broiler Chickens

2021 ◽  
Vol 8 (6) ◽  
pp. 110
Author(s):  
Nathalie Meijerink ◽  
Jean E. de Oliveira ◽  
Daphne A. van Haarlem ◽  
Guilherme Hosotani ◽  
David M. Lamot ◽  
...  
Keyword(s):  
Immune System ◽  
Nk Cells ◽  
Relative Abundance ◽  
Nk Cell ◽  
Feed Additives ◽  
Microbiota Composition ◽  
In Ovo ◽  
Long Chain

Restrictions on the use of antibiotics in the poultry industry stimulate the development of alternative nutritional solutions to maintain or improve poultry health. This requires more insight in the modulatory effects of feed additives on the immune system and microbiota composition. Compounds known to influence the innate immune system and microbiota composition were selected and screened in vitro, in ovo, and in vivo. Among all compounds, 57 enhanced NK cell activation, 56 increased phagocytosis, and 22 increased NO production of the macrophage cell line HD11 in vitro. Based on these results, availability and regulatory status, six compounds were selected for further analysis. None of these compounds showed negative effects on growth, hatchability, and feed conversion in in ovo and in vivo studies. Based on the most interesting numerical results and highest future potential feasibility, two compounds were analyzed further. Administration of glucose oligosaccharide and long-chain glucomannan in vivo both enhanced activation of intraepithelial NK cells and led to increased relative abundance of lactic acid bacteria (LAB) amongst ileum and ceca microbiota after seven days of supplementation. Positive correlations between NK cell subsets and activation, and relative abundance of LAB suggest the involvement of microbiota in the modulation of the function of intraepithelial NK cells. This study identifies glucose oligosaccharide and long-chain glucomannan supplementation as effective nutritional strategies to modulate the intestinal microbiota composition and strengthen the intraepithelial innate immune system.

scholarly journals Fibrillar pharmacology of functionalized nanocellulose

2021 ◽  
Vol 11 (1) ◽  
Author(s):  
Sam Wong ◽  
Simone Alidori ◽  
Barbara P. Mello ◽  
Bryan Aristega Almeida ◽  
David Ulmert ◽  
...  
Keyword(s):  
Aspect Ratio ◽  
Fluorescent Dyes ◽  
Pharmacokinetic Profile ◽  
Water Soluble ◽  
Size Exclusion ◽  
Hydroxyl Groups ◽  
Target Tissue ◽  
Exclusion Chromatography ◽  
Specific Accumulation

AbstractCellulose nanocrystals (CNC) are linear organic nanomaterials derived from an abundant naturally occurring biopolymer resource. Strategic modification of the primary and secondary hydroxyl groups on the CNC introduces amine and iodine group substitution, respectively. The amine groups (0.285 mmol of amine per gram of functionalized CNC (fCNC)) are further reacted with radiometal loaded-chelates or fluorescent dyes as tracers to evaluate the pharmacokinetic profile of the fCNC in vivo. In this way, these nanoscale macromolecules can be covalently functionalized and yield water-soluble and biocompatible fibrillar nanoplatforms for gene, drug and radionuclide delivery in vivo. Transmission electron microscopy of fCNC reveals a length of 162.4 ± 16.3 nm, diameter of 11.2 ± 1.52 nm and aspect ratio of 16.4 ± 1.94 per particle (mean ± SEM) and is confirmed using atomic force microscopy. Size exclusion chromatography of macromolecular fCNC describes a fibrillar molecular behavior as evidenced by retention times typical of late eluting small molecules and functionalized carbon nanotubes. In vivo, greater than 50% of intravenously injected radiolabeled fCNC is excreted in the urine within 1 h post administration and is consistent with the pharmacological profile observed for other rigid, high aspect ratio macromolecules. Tissue distribution of fCNC shows accumulation in kidneys, liver, and spleen (14.6 ± 6.0; 6.1 ± 2.6; and 7.7 ± 1.4% of the injected activity per gram of tissue, respectively) at 72 h post-administration. Confocal fluorescence microscopy reveals cell-specific accumulation in these target tissue sinks. In summary, our findings suggest that functionalized nanocellulose can be used as a potential drug delivery platform for the kidneys.

scholarly journals Cortical Excitability across the ALS Clinical Motor Phenotypes

2021 ◽  
Vol 11 (6) ◽  
pp. 715
Author(s):  
Thanuja Dharmadasa
Keyword(s):  
Motor Cortex ◽  
Cortical Excitability ◽  
Phenotypic Variability ◽  
Specific Treatment ◽  
Underlying Disease ◽  
Selective Vulnerability ◽  
Clinical Feature ◽  
Cortical Hyperexcitability ◽  
Wide Range

Amyotrophic lateral sclerosis (ALS) is characterized by its marked clinical heterogeneity. Although the coexistence of upper and lower motor neuron signs is a common clinical feature for most patients, there is a wide range of atypical motor presentations and clinical trajectories, implying a heterogeneity of underlying pathogenic mechanisms. Corticomotoneuronal dysfunction is increasingly postulated as the harbinger of clinical disease, and neurophysiological exploration of the motor cortex in vivo using transcranial magnetic stimulation (TMS) has suggested that motor cortical hyperexcitability may be a critical pathogenic factor linked to clinical features and survival. Region-specific selective vulnerability at the level of the motor cortex may drive the observed differences of clinical presentation across the ALS motor phenotypes, and thus, further understanding of phenotypic variability in relation to cortical dysfunction may serve as an important guide to underlying disease mechanisms. This review article analyses the cortical excitability profiles across the clinical motor phenotypes, as assessed using TMS, and explores this relationship to clinical patterns and survival. This understanding will remain essential to unravelling central disease pathophysiology and for the development of specific treatment targets across the ALS clinical motor phenotypes.

scholarly journals Sesquiterpene Lactones: Promising Natural Compounds to Fight Inflammation

Pharmaceutics ◽  
2021 ◽  
Vol 13 (7) ◽  
pp. 991
Author(s):  
Melanie S. Matos ◽  
José D. Anastácio ◽  
Cláudia Nunes dos Santos
Keyword(s):  
Biological Activities ◽  
Sesquiterpene Lactones ◽  
Physiological State ◽  
Plant Secondary Metabolites ◽  
Inflammatory Pathways ◽  
Inflammatory State ◽  
Anti Inflammatory ◽  
Inflammatory Molecules

Inflammation is a crucial and complex process that reestablishes the physiological state after a noxious stimulus. In pathological conditions the inflammatory state may persist, leading to chronic inflammation and causing tissue damage. Sesquiterpene lactones (SLs) are composed of a large and diverse group of highly bioactive plant secondary metabolites, characterized by a 15-carbon backbone structure. In recent years, the interest in SLs has risen due to their vast array of biological activities beneficial for human health. The anti-inflammatory potential of these compounds results from their ability to target and inhibit various key pro-inflammatory molecules enrolled in diverse inflammatory pathways, and prevent or reduce the inflammatory damage on tissues. Research on the anti-inflammatory mechanisms of SLs has thrived over the last years, and numerous compounds from diverse plants have been studied, using in silico, in vitro, and in vivo assays. Besides their anti-inflammatory potential, their cytotoxicity, structure–activity relationships, and pharmacokinetics have been investigated. This review aims to gather the most relevant results and insights concerning the anti-inflammatory potential of SL-rich extracts and pure SLs, focusing on their effects in different inflammatory pathways and on different molecular players.

scholarly journals Ovarian Accumulation of Nanoemulsions: Impact of Mice Age and Particle Size

2021 ◽  
Vol 22 (15) ◽  
pp. 8283
Author(s):  
Eike Folker Busmann ◽  
Julia Kollan ◽  
Karsten Mäder ◽  
Henrike Lucas
Keyword(s):  
Particle Size ◽  
Ex Vivo ◽  
Reticuloendothelial System ◽  
Systematic Investigation ◽  
Measured Signal ◽  
Reproductive Aging ◽  
Sex Steroid Hormone ◽  
Adult Mice ◽  
Radiant Efficiency

Nanotechnology in the field of drug delivery comes with great benefits due to the unique physicochemical properties of newly developed nanocarriers. However, they may come as well with severe toxicological side effects because of unwanted accumulation in organs outside of their targeted site of actions. Several studies showed an unintended accumulation of various nanocarriers in female sex organs, especially in the ovaries. Some led to inflammation, fibrosis, or decreasing follicle numbers. However, none of these studies investigated ovarian accumulation in context to both reproductive aging and particle size. Besides the influences of particle size, the biodistribution profile may be altered as well by reproductive aging because of reduced capacities of the reticuloendothelial system (RES), changes in sex steroid hormone levels as well as altering ovarian stromal blood flow. This systematic investigation of the biodistribution of intravenously (i.v) injected nanoemulsions revealed significant dependencies on the two parameters particle size and age starting from juvenile prepubescent to senescent mice. Using fluorescent in vivo and ex vivo imaging, prepubescent mice showed nearly no accumulation of nanoemulsion in their uteri and ovaries, but high accumulations in the organs of the RES liver and spleen independently of the particle size. In fertile adult mice, the accumulation increased significantly in the ovaries with an increased particle size of the nanoemulsions by nearly doubling the portion of the average radiant efficiency (PARE) to ~10% of the total measured signal of all excised organs. With reproductive aging and hence loss of fertility in senescent mice, the accumulation decreased again to moderate levels, again independently of the particle size. In conclusion, the ovarian accumulation of these nanocarriers depended on both the age plus the particle size during maturity.

scholarly journals Antioxidant Properties of Ergosterol and Its Role in Yeast Resistance to Oxidation

Antioxidants ◽  
2021 ◽  
Vol 10 (7) ◽  
pp. 1024
Author(s):  
Sebastien Dupont ◽  
Paul Fleurat-Lessard ◽  
Richtier Gonçalves Cruz ◽  
Céline Lafarge ◽  
Cédric Grangeteau ◽  
...  
Keyword(s):  
Computational Study ◽  
Antioxidant Properties ◽  
Beneficial Effects ◽  
Tert Butyl Hydroperoxide ◽  
Resistance To Oxidation ◽  
Specific Accumulation ◽  
The Subject

Although the functions and structural roles of sterols have been the subject of numerous studies, the reasons for the diversity of sterols in the different eukaryotic kingdoms remain unclear. It is thought that the specificity of sterols is linked to unidentified supplementary functions that could enable organisms to be better adapted to their environment. Ergosterol is accumulated by late branching fungi that encounter oxidative perturbations in their interfacial habitats. Here, we investigated the antioxidant properties of ergosterol using in vivo, in vitro, and in silico approaches. The results showed that ergosterol is involved in yeast resistance to tert-butyl hydroperoxide and protects lipids against oxidation in liposomes. A computational study based on quantum chemistry revealed that this protection could be related to its antioxidant properties operating through an electron transfer followed by a proton transfer mechanism. This study demonstrates the antioxidant role of ergosterol and proposes knowledge elements to explain the specific accumulation of this sterol in late branching fungi. Ergosterol, as a natural antioxidant molecule, could also play a role in the incompletely understood beneficial effects of some mushrooms on health.

scholarly journals Lack of WWC2 Protein Leads to Aberrant Angiogenesis in Postnatal Mice

2021 ◽  
Vol 22 (10) ◽  
pp. 5321
Author(s):  
Viktoria Constanze Brücher ◽  
Charlotte Egbring ◽  
Tanja Plagemann ◽  
Pavel I. Nedvetsky ◽  
Verena Höffken ◽  
...  
Keyword(s):  
Signalling Pathway ◽  
Control Group ◽  
Knock Out ◽  
Ocular Angiogenesis ◽  
Sprouting Angiogenesis ◽  
Adult Mice ◽  
Upstream Regulator ◽  
Knock Out Mice ◽  
Hippo Signalling

The WWC protein family is an upstream regulator of the Hippo signalling pathway that is involved in many cellular processes. We examined the effect of an endothelium-specific WWC1 and/or WWC2 knock-out on ocular angiogenesis. Knock-outs were induced in C57BL/6 mice at the age of one day (P1) and evaluated at P6 (postnatal mice) or induced at the age of five weeks and evaluated at three months of age (adult mice). We analysed morphology of retinal vasculature in retinal flat mounts. In addition, in vivo imaging and functional testing by electroretinography were performed in adult mice. Adult WWC1/2 double knock-out mice differed neither functionally nor morphologically from the control group. In contrast, the retinas of the postnatal WWC knock-out mice showed a hyperproliferative phenotype with significantly enlarged areas of sprouting angiogenesis and a higher number of tip cells. The branching and end points in the peripheral plexus were significantly increased compared to the control group. The deletion of the WWC2 gene was decisive for these effects; while knocking out WWC1 showed no significant differences. The results hint strongly that WWC2 is an essential regulator of ocular angiogenesis in mice. As an activator of the Hippo signalling pathway, it prevents excessive proliferation during physiological angiogenesis. In adult animals, WWC proteins do not seem to be important for the maintenance of the mature vascular plexus.

scholarly journals Identification of the MuRF1 skeletal muscle ubiquitylome through quantitative proteomics

Function ◽  
2021 ◽  
Author(s):  
Leslie M Baehr ◽  
David C Hughes ◽  
Sarah A Lynch ◽  
Delphi Van Haver ◽  
Teresa Mendes Maia ◽  
...  
Keyword(s):  
Skeletal Muscle ◽  
Muscle Atrophy ◽  
Potential Role ◽  
Ubiquitin Proteasome System ◽  
In Vivo Electroporation ◽  
Adult Mice ◽  
Expression Of Genes ◽  
Regulation Of Metabolism ◽  
Ubiquitin Proteasome

Abstract MuRF1 (TRIM63) is a muscle-specific E3 ubiquitin ligase and component of the ubiquitin proteasome system. MuRF1 is transcriptionally upregulated under conditions that cause muscle loss, in both rodents and humans, and is a recognized marker of muscle atrophy. In this study, we used in vivo electroporation to determine if MuRF1 overexpression alone can cause muscle atrophy and, in combination with ubiquitin proteomics, identify the endogenous MuRF1 substrates in skeletal muscle. Overexpression of MuRF1 in adult mice increases ubiquitination of myofibrillar and sarcoplasmic proteins, increases expression of genes associated with neuromuscular junction instability, and causes muscle atrophy. A total of 169 ubiquitination sites on 56 proteins were found to be regulated by MuRF1. MuRF1-mediated ubiquitination targeted both thick and thin filament contractile proteins, as well as, glycolytic enzymes, deubiquitinases, p62, and VCP. These data reveal a potential role for MuRF1 in not only the breakdown of the sarcomere, but also the regulation of metabolism and other proteolytic pathways in skeletal muscle.

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