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Wilson MR, Satapathy S, Vendruscolo M. Extracellular protein homeostasis in neurodegenerative diseases. Nat Rev Neurol 2023; 19:235-245. [PMID: 36828943 DOI: 10.1038/s41582-023-00786-2] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Accepted: 02/02/2023] [Indexed: 02/26/2023]
Abstract
The protein homeostasis (proteostasis) system encompasses the cellular processes that regulate protein synthesis, folding, concentration, trafficking and degradation. In the case of intracellular proteostasis, the identity and nature of these processes have been extensively studied and are relatively well known. By contrast, the mechanisms of extracellular proteostasis are yet to be fully elucidated, although evidence is accumulating that their age-related progressive impairment might contribute to neuronal death in neurodegenerative diseases. Constitutively secreted extracellular chaperones are emerging as key players in processes that operate to protect neurons and other brain cells by neutralizing the toxicity of extracellular protein aggregates and promoting their safe clearance and disposal. Growing evidence indicates that these extracellular chaperones exert multiple effects to promote cell viability and protect neurons against pathologies arising from the misfolding and aggregation of proteins in the synaptic space and interstitial fluid. In this Review, we outline the current knowledge of the mechanisms of extracellular proteostasis linked to neurodegenerative diseases, and we examine the latest understanding of key molecules and processes that protect the brain from the pathological consequences of extracellular protein aggregation and proteotoxicity. Finally, we contemplate possible therapeutic opportunities for neurodegenerative diseases on the basis of this emerging knowledge.
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Affiliation(s)
- Mark R Wilson
- School of Chemistry and Molecular Bioscience, Molecular Horizons Research Institute, University of Wollongong, Wollongong, New South Wales, Australia.
| | - Sandeep Satapathy
- Blavatnik Institute of Cell Biology, Harvard Medical School, Boston, MA, USA
| | - Michele Vendruscolo
- Centre for Misfolding Diseases, Yusuf Hamied Department of Chemistry, University of Cambridge, Cambridge, UK
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2
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Michalski D, Reimann W, Spielvogel E, Mages B, Biedermann B, Barthel H, Nitzsche B, Schob S, Härtig W. Regionally Altered Immunosignals of Surfactant Protein-G, Vascular and Non-Vascular Elements of the Neurovascular Unit after Experimental Focal Cerebral Ischemia in Mice, Rats, and Sheep. Int J Mol Sci 2022; 23:ijms23115875. [PMID: 35682557 PMCID: PMC9180438 DOI: 10.3390/ijms23115875] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/10/2022] [Revised: 05/14/2022] [Accepted: 05/19/2022] [Indexed: 01/12/2023] Open
Abstract
The surfactant protein-G (SP-G) has recently been discovered in the brain and linked to fluid balance regulations. Stroke is characterized by impaired vessel integrity, promoting water influx and edema formation. The neurovascular unit concept (NVU) has been generated to cover not only ischemic affections of neurons or vessels but also other regionally associated cells. This study provides the first spatio-temporal characterization of SP-G and NVU elements after experimental stroke. Immunofluorescence labeling was applied to explore SP-G, vascular and cellular markers in mice (4, 24, and 72 h of ischemia), rats (24 h of ischemia), and sheep (two weeks of ischemia). Extravasated albumin indicated vascular damage within ischemic areas. Quantifications revealed decreasing SP-G signals in the ischemia-affected neocortex and subcortex. Inverse immunosignals of SP-G and vascular elements existed throughout all models. Despite local associations between SP-G and the vasculature, a definite co-localization was not seen. Along with a decreased SP-G-immunoreactivity in ischemic areas, signals originating from neurons, glial elements, and the extracellular matrix exhibited morphological alterations or changed intensities. Collectively, this study revealed regional alterations of SP-G, vascular, and non-vascular NVU elements after ischemia, and may thus stimulate the discussion about the role of SP-G during stroke.
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Affiliation(s)
- Dominik Michalski
- Department of Neurology, University of Leipzig, Liebigstr. 20, 04103 Leipzig, Germany; (W.R.); (E.S.)
- Correspondence: ; Tel.: +49-341-9724339
| | - Willi Reimann
- Department of Neurology, University of Leipzig, Liebigstr. 20, 04103 Leipzig, Germany; (W.R.); (E.S.)
- Paul Flechsig Institute for Brain Research, University of Leipzig, Liebigstr. 19, 04103 Leipzig, Germany; (B.B.); (W.H.)
| | - Emma Spielvogel
- Department of Neurology, University of Leipzig, Liebigstr. 20, 04103 Leipzig, Germany; (W.R.); (E.S.)
- Paul Flechsig Institute for Brain Research, University of Leipzig, Liebigstr. 19, 04103 Leipzig, Germany; (B.B.); (W.H.)
| | - Bianca Mages
- Institute of Anatomy, University of Leipzig, Liebigstr. 13, 04103 Leipzig, Germany;
| | - Bernd Biedermann
- Paul Flechsig Institute for Brain Research, University of Leipzig, Liebigstr. 19, 04103 Leipzig, Germany; (B.B.); (W.H.)
| | - Henryk Barthel
- Department of Nuclear Medicine, University of Leipzig, Stephanstr. 11, 04103 Leipzig, Germany; (H.B.); (B.N.)
| | - Björn Nitzsche
- Department of Nuclear Medicine, University of Leipzig, Stephanstr. 11, 04103 Leipzig, Germany; (H.B.); (B.N.)
- Institute of Anatomy, Histology, and Embryology, Faculty of Veterinary Medicine, University of Leipzig, An den Tierkliniken 43, 04103 Leipzig, Germany
| | - Stefan Schob
- Department of Neuroradiology, University of Halle, Ernst-Grube-Str. 40, 06120 Halle (Saale), Germany;
| | - Wolfgang Härtig
- Paul Flechsig Institute for Brain Research, University of Leipzig, Liebigstr. 19, 04103 Leipzig, Germany; (B.B.); (W.H.)
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3
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Meinicke A, Härtig W, Winter K, Puchta J, Mages B, Michalski D, Emmer A, Otto M, Hoffmann KT, Reimann W, Krause M, Schob S. Surfactant Protein-G in Wildtype and 3xTg-AD Mice: Localization in the Forebrain, Age-Dependent Hippocampal Dot-like Deposits and Brain Content. Biomolecules 2022; 12:biom12010096. [PMID: 35053244 PMCID: PMC8773979 DOI: 10.3390/biom12010096] [Citation(s) in RCA: 2] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/09/2021] [Revised: 12/30/2021] [Accepted: 12/31/2021] [Indexed: 11/16/2022] Open
Abstract
The classic surfactant proteins (SPs) A, B, C, and D were discovered in the lungs, where they contribute to host defense and regulate the alveolar surface tension during breathing. Their additional importance for brain physiology was discovered decades later. SP-G, a novel amphiphilic SP, was then identified in the lungs and is mostly linked to inflammation. In the brain, it is also present and significantly elevated after hemorrhage in premature infants and in distinct conditions affecting the cerebrospinal fluid circulation of adults. However, current knowledge on SP-G-expression is limited to ependymal cells and some neurons in the subventricular and superficial cortex. Therefore, we primarily focused on the distribution of SP-G-immunoreactivity (ir) and its spatial relationships with components of the neurovascular unit in murine forebrains. Triple fluorescence labeling elucidated SP-G-co-expressing neurons in the habenula, infundibulum, and hypothalamus. Exploring whether SP-G might play a role in Alzheimer’s disease (AD), 3xTg-AD mice were investigated and displayed age-dependent hippocampal deposits of β-amyloid and hyperphosphorylated tau separately from clustered, SP-G-containing dots with additional Reelin-ir—which was used as established marker for disease progression in this specific context. Semi-quantification of those dots, together with immunoassay-based quantification of intra- and extracellular SP-G, revealed a significant elevation in old 3xTg mice when compared to age-matched wildtype animals. This suggests a role of SP-G for the pathophysiology of AD, but a confirmation with human samples is required.
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Affiliation(s)
- Anton Meinicke
- Paul Flechsig Institute for Brain Research, University of Leipzig, Liebigstr. 19, 04103 Leipzig, Germany; (A.M.); (W.H.); (J.P.); (W.R.)
- Institute of Neuroradiology, University Hospital Leipzig, Liebigstr. 20, 04103 Leipzig, Germany;
| | - Wolfgang Härtig
- Paul Flechsig Institute for Brain Research, University of Leipzig, Liebigstr. 19, 04103 Leipzig, Germany; (A.M.); (W.H.); (J.P.); (W.R.)
| | - Karsten Winter
- Institute of Anatomy, University of Leipzig, Liebigstr. 13, 04103 Leipzig, Germany; (K.W.); (B.M.)
| | - Joana Puchta
- Paul Flechsig Institute for Brain Research, University of Leipzig, Liebigstr. 19, 04103 Leipzig, Germany; (A.M.); (W.H.); (J.P.); (W.R.)
- Institute of Neuroradiology, University Hospital Leipzig, Liebigstr. 20, 04103 Leipzig, Germany;
| | - Bianca Mages
- Institute of Anatomy, University of Leipzig, Liebigstr. 13, 04103 Leipzig, Germany; (K.W.); (B.M.)
| | - Dominik Michalski
- Department of Neurology, University Hospital Leipzig, Liebigstr. 20, 04103 Leipzig, Germany;
| | - Alexander Emmer
- Department of Neurology, University Hospital Halle, Ernst-Grube-Str. 40, 06120 Halle (Saale), Germany; (A.E.); (M.O.)
| | - Markus Otto
- Department of Neurology, University Hospital Halle, Ernst-Grube-Str. 40, 06120 Halle (Saale), Germany; (A.E.); (M.O.)
| | - Karl-Titus Hoffmann
- Institute of Neuroradiology, University Hospital Leipzig, Liebigstr. 20, 04103 Leipzig, Germany;
| | - Willi Reimann
- Paul Flechsig Institute for Brain Research, University of Leipzig, Liebigstr. 19, 04103 Leipzig, Germany; (A.M.); (W.H.); (J.P.); (W.R.)
- Institute of Neuroradiology, University Hospital Leipzig, Liebigstr. 20, 04103 Leipzig, Germany;
| | - Matthias Krause
- Department of Neurosurgery, University Hospital Leipzig, Liebigstr. 20, 04103 Leipzig, Germany;
| | - Stefan Schob
- Department of Neuroradiology, Clinic and Policlinic of Radiology, University Hospital Halle, Ernst-Grube-Str. 40, 06120 Halle (Saale), Germany
- Correspondence: ; Tel.: +49-345-557-2432
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4
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Identifying new molecular players in extracellular proteostasis. Biochem Soc Trans 2021; 50:321-334. [PMID: 34940856 DOI: 10.1042/bst20210369] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/14/2021] [Revised: 12/07/2021] [Accepted: 12/09/2021] [Indexed: 02/02/2023]
Abstract
Proteostasis refers to a delicately tuned balance between the processes of protein synthesis, folding, localization, and the degradation of proteins found inside and outside cells. Our understanding of extracellular proteostasis is rather limited and largely restricted to knowledge of 11 currently established extracellular chaperones (ECs). This review will briefly outline what is known of the established ECs, before moving on to discuss experimental strategies used to identify new members of this growing family, and an examination of a group of putative new ECs identified using one of these approaches. An observation that emerges from an analysis of the expanding number of ECs is that all of these proteins are multifunctional. Strikingly, the armory of activities each possess uniquely suit them as a group to act together at sites of tissue damage, infection, and inflammation to restore homeostasis. Lastly, we highlight outstanding questions to guide future research in this field.
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Schob S, Puchta J, Winter K, Michalski D, Mages B, Martens H, Emmer A, Hoffmann KT, Gaunitz F, Meinicke A, Krause M, Härtig W. Surfactant protein C is associated with perineuronal nets and shows age-dependent changes of brain content and hippocampal deposits in wildtype and 3xTg mice. J Chem Neuroanat 2021; 118:102036. [PMID: 34626771 DOI: 10.1016/j.jchemneu.2021.102036] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/12/2021] [Revised: 09/24/2021] [Accepted: 09/24/2021] [Indexed: 01/15/2023]
Abstract
Surfactant protein C (SP-C) modulates cerebrospinal fluid (CSF) rheology. During ageing, its declining levels are accompanied by an increased burden of white matter lesions. Pulmonary SP-C intermediates harbouring the BRICHOS-domain prevent protein misfolding in the lungs. Thus, cerebral SP-C intermediates may counteract cerebral β-amyloidosis, a hallmark of Alzheimer's disease (AD). However, data on the molecular neuroanatomy of SP-C and its alterations in wildtype and triple transgenic (3xTg) mice, featuring essential elements of AD-neuropathology, are lacking. Therefore, this study investigated SP-C-containing structures in murine forebrains and their spatial relationships with vascular, glial and neuronal components of the neurovascular unit. Fluorescence labelling demonstrated neuronal SP-C in the medial habenula, the indusium griseum and the hippocampus. Glial counterstaining elucidated astrocytes in the corpus callosum co-expressing SP-C and S100β. Notably, perineuronal nets were associated with SP-C in the nucleus reticularis thalami, the lateral hypothalamus and the retrosplenial cortex. In the hippocampus of aged 3xTg mice, an increased number of dot-like depositions containing SP-C and Reelin, but devoid of BRICHOS-immunoreactivity were observed apart from AD-like lesions. Wildtype and 3xTg mice revealed an age-dependent increase of such deposits markedly pronounced in about 24-month-old 3xTg mice. SP-C levels of the intracellular and extracellular compartments in each group revealed an inverse correlation of SP-C and Reelin, with reduced SP-C and increased Reelin in an age-dependent fashion especially in 3xTg mice. Taken together, extracellular SP-C, as modulator of glymphatic clearance and potential ligand of PNs, declines in 3xTg mice, which show an accumulation of extracellular Reelin depositions during ageing.
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Affiliation(s)
- Stefan Schob
- Department of Neuroradiology, Clinic and Policlinic of Radiology, University Hospital Halle, Ernst-Grube-Str. 40, 06120 Halle/Saale, Germany.
| | - Joana Puchta
- Paul Flechsig Institute for Brain Research, University of Leipzig, Liebigstr.19, 04103 Leipzig, Germany; Institute of Neuroradiology, University of Leipzig, Liebigstr. 20, 04103 Leipzig, Germany
| | - Karsten Winter
- Institute for Anatomy, University of Leipzig, Liebigstr. 13, 04103 Leipzig, Germany
| | - Dominik Michalski
- Department of Neurology, University of Leipzig, Liebigstr. 13, 04103 Leipzig, Germany
| | - Bianca Mages
- Institute for Anatomy, University of Leipzig, Liebigstr. 13, 04103 Leipzig, Germany
| | - Henrik Martens
- Synaptic Systems GmbH, Rudolf-Wissell-Str. 28a, 37079 Göttingen, Germany
| | - Alexander Emmer
- Department of Neurology, Martin Luther University Halle-Wittenberg, Ernst-Grube-Str. 40, 06120 Halle/Saale, Germany
| | - Karl-Titus Hoffmann
- Institute of Neuroradiology, University of Leipzig, Liebigstr. 20, 04103 Leipzig, Germany
| | - Frank Gaunitz
- Department of Neurosurgery, University of Leipzig, Liebigstr. 20, 04103 Leipzig, Germany
| | - Anton Meinicke
- Paul Flechsig Institute for Brain Research, University of Leipzig, Liebigstr.19, 04103 Leipzig, Germany; Institute of Neuroradiology, University of Leipzig, Liebigstr. 20, 04103 Leipzig, Germany
| | - Matthias Krause
- Department of Neurosurgery, University of Leipzig, Liebigstr. 20, 04103 Leipzig, Germany
| | - Wolfgang Härtig
- Paul Flechsig Institute for Brain Research, University of Leipzig, Liebigstr.19, 04103 Leipzig, Germany
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6
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Krause M, Härtig W, Mahr CV, Richter C, Schob J, Puchta J, Hoffmann KT, Nestler U, Thome U, Knüpfer M, Gebauer C, Schob S. CSF Surfactant Protein Changes in Preterm Infants After Intraventricular Hemorrhage. Front Pediatr 2020; 8:572851. [PMID: 33102410 PMCID: PMC7546901 DOI: 10.3389/fped.2020.572851] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 06/15/2020] [Accepted: 08/12/2020] [Indexed: 11/13/2022] Open
Abstract
Introduction: Surfactant proteins (SP) have been shown to be inherent proteins of the human CNS and are altered during acute and chronic disturbances of CSF circulation. Aim of the study was to examine the changes of surfactant protein concentrations in CSF of preterm babies suffering from intraventricular hemorrhage. Patients and Methods: Consecutive CSF samples of 21 preterm infants with intraventricular hemorrhages (IVH) and posthemorrhagic hydrocephalus (PHHC) were collected at primary intervention, after 5-10 days and at time of shunt insertion ~50 days after hemorrhage. Samples were analyzed for surfactant proteins A, B, C, and G by ELISA assays and the results were compared to 35 hydrocephalus patients (HC) without hemorrhage and 6 newborn control patients. Results and Discussion: Premature patients with IVH showed a significant elevation of surfactant proteins SP-A, C, and G compared to HC and control groups: mean values for the respective groups were SP-A 4.19 vs. 1.08 vs. 0.38 ng/ml. Mean SP-C 3.63 vs. 1.47 vs. 0.48 ng/ml. Mean SP-G 3.86 vs. 0.17 vs. 0.2 ng/ml. SP-A and G concentrations were slowly falling over time without reaching normal values. SP-C levels declined faster following neurosurgical interventions and reached levels comparable to those of hydrocephalus patients without hemorrhage. Conclusion: Intraventricular hemorrhages of premature infants cause posthemorrhagic CSF flow disturbance and are associated with highly significant elevations of surfactant proteins A, C, and G independent of total CSF protein concentrations.
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Affiliation(s)
- Matthias Krause
- Department of Neurosurgery, University Hospital Leipzig, Leipzig, Germany
| | - Wolfgang Härtig
- Paul Flechsig Institute for Brain Research, Medical Faculty of University Leipzig, Leipzig, Germany.,Department of Neuroradiology, University Hospital Leipzig, Leipzig, Germany
| | | | - Cindy Richter
- Department of Neuroradiology, University Hospital Leipzig, Leipzig, Germany
| | - Julia Schob
- Department of Ophthalmology, University Hospital Leipzig, Leipzig, Germany
| | - Joana Puchta
- Paul Flechsig Institute for Brain Research, Medical Faculty of University Leipzig, Leipzig, Germany.,Department of Neuroradiology, University Hospital Leipzig, Leipzig, Germany
| | | | - Ulf Nestler
- Department of Neurosurgery, University Hospital Leipzig, Leipzig, Germany
| | - Ulrich Thome
- Department of Neonatology, University Hospital Leipzig, Leipzig, Germany
| | - Matthias Knüpfer
- Department of Neonatology, University Hospital Leipzig, Leipzig, Germany
| | - Corinna Gebauer
- Department of Neonatology, University Hospital Leipzig, Leipzig, Germany
| | - Stefan Schob
- Department of Neuroradiology, University Hospital Leipzig, Leipzig, Germany
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7
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Weiß A, Krause M, Stockert A, Richter C, Puchta J, Bhogal P, Hoffmann KT, Emmer A, Quäschling U, Scherlach C, Härtig W, Schob S. Rheologically Essential Surfactant Proteins of the CSF Interacting with Periventricular White Matter Changes in Hydrocephalus Patients - Implications for CSF Dynamics and the Glymphatic System. Mol Neurobiol 2019; 56:7863-7871. [PMID: 31127529 DOI: 10.1007/s12035-019-01648-z] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.4] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/25/2019] [Accepted: 05/13/2019] [Indexed: 10/26/2022]
Abstract
Surfactant proteins (SP) are multi-systemic proteins playing crucial roles in the regulation of rheological properties of physiological fluids, host defense, and the clearance of potentially harmful metabolites. Hydrocephalus patients suffer from disturbed central nervous system (CNS) fluid homeostasis and exhibit remarkably altered SP concentrations within the cerebrospinal fluid (CSF). A connection between CSF-SPs, CSF flow, and ventricular dilatation, a morphological hallmark of hydrocephalus, has been reported previously. However, currently there are no studies investigating the link between rheologically active SPs and periventricular white matter changes caused by impaired CSF microcirculation in hydrocephalic conditions. Thus, the aim of this study was to assess their possible relationships. The present study included 47 individuals (27 healthy subjects and 20 hydrocephalus patients). CSF specimens were analyzed for concentrations of SP-A, SP-C, and SP-D by using enzyme-linked immunosorbent assays (ELISAs). Axial T2w turbo inversion recovery magnitude (TIRM) magnetic resonance imaging was employed in all cases. Using a custom-made MATLAB-based tool for quantification of magnetic resonance signal intensities in the brain, parameters related to disturbed deep white matter CSF microcirculation were estimated (TIRM signal intensity (SI)-mean, minimum, maximum, median, mode, standard deviation, and percentiles, p10th, p25th, p75th, p90th, as well as kurtosis, skewness, and entropy of the SI distribution). Subsequently, statistical analysis was performed (IBM SPSS 24™) to identify differences between hydrocephalic patients and healthy individuals and to further investigate the connections between CSF-SP changes and deep white matter signal intensities. SP-A (0.38 ± 0.23 vs. 0.76 ± 0.49 ng/ml) and SP-C (0.54 ± 0.28 vs. 1.27 ± 1.09 ng/ml) differed between healthy controls and hydrocephalus patients in a statistically significant manner. Also, corresponding quantification of white matter signal intensities revealed statistically significant differences between hydrocephalus patients and healthy individuals: SImean (370.41 ± 188.15 vs. 222.27 ± 99.86, p = 0.001), SImax (1115.30 ± 700.12 vs. 617.00 ± 459.34, p = 0.005), SImedian (321.40 ± 153.17 vs. 209.52 ± 84.86, p = 0.001), SImode (276.55 ± 125.63 vs. 197.26 ± 78.51, p = 0.011), SIstd (157.09 ± 110.07 vs. 81.71 ± 64.94, p = 0.005), SIp10 (229.10 ± 104.22 vs. 140.00 ± 63.12, p = 0.001), SIp25 (266.95 ± 122.62 vs. 175.63 ± 71.42, p = 0.002), SIp75 (428.80 ± 226.88 vs. 252.19 ± 110.91, p = 0.001), SIp90 (596.47 ± 345.61 vs. 322.06 ± 176.00, p = 0.001), skewness (1.19 ± 0.68 vs. 0.43 ± 1.19, p = 0.014), and entropy (5.36 ± 0.37 vs. 4.92 ± 0.51, p = 0.002). There were no differences regarding SP-D levels in hydrocephalus patients vs. healthy controls. In the acute hydrocephalic subgroup, correlations were as follows: SP-A showed a statistically significant correlation with SImax (r = 0.670, p = 0.024), SIstd (r = 0.697, p = 0.017), SIp90 (r = 0.621, p = 0.041), and inverse correlation with entropy (r = - 0.700, p = 0.016). SP-C correlated inversely with entropy (r = - 0.686, p = 0.020). For the chronic hydrocephalus subgroup, the following correlations were identified: SP-A correlated with kurtosis of the TIRM histogram (r = - 0.746, p = 0.021). SP-C correlated with SImean (r = - 0.688, p = 0.041), SImax (r = - 0.741, p = 0.022), SImedian (r = - 0.716, p = 0.030), SImode (r = - 0.765, p = 0.016), SIstd (r = - 0.671, p = 0.048), SIp25 (r = - 0.740, p = 0.023), SIp75 (r = - 0.672, p = 0.048), and SIp90 (r = - 0.667, p = 0.050). SP-D apparently does not play a major role in CSF fluid physiology. SP-A and SP-C are involved in different aspects of CNS fluid physiology. SP-A appears to play an essential compensatory role in acute hydrocephalus and seems less involved in chronic hydrocephalus. In contrary, SP-C profile and white matter changes are remarkably connected in CSF of chronic hydrocephalus patients. Considering the association between CSF flow phenomena, white matter changes, and SP-C profiles, the latter may especially contribute to the regulation of paravascular glymphatic physiology.
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Affiliation(s)
- Alexander Weiß
- Department of Neuroradiology, University Hospital Leipzig, Liebigstrasse 20, 04103, Leipzig, Germany
| | - Matthias Krause
- Department of Neurosurgery, University Hospital Leipzig, Leipzig, Germany
| | - Anika Stockert
- Department of Neurology, University Hospital Leipzig, Leipzig, Germany
| | - Cindy Richter
- Department of Neuroradiology, University Hospital Leipzig, Liebigstrasse 20, 04103, Leipzig, Germany
| | - Joana Puchta
- Department of Neuroradiology, University Hospital Leipzig, Liebigstrasse 20, 04103, Leipzig, Germany.,Paul Flechsig Institute for Brain Research, University Leipzig, Leipzig, Germany
| | - Pervinder Bhogal
- Department of Interventional Neuroradiology, Royal London Hospital, London, UK
| | - Karl-Titus Hoffmann
- Department of Neuroradiology, University Hospital Leipzig, Liebigstrasse 20, 04103, Leipzig, Germany
| | - Alexander Emmer
- Department for Neurology, University Hospital Halle-Wittenberg, Halle, Germany
| | - Ulf Quäschling
- Department of Neuroradiology, University Hospital Leipzig, Liebigstrasse 20, 04103, Leipzig, Germany
| | - Cordula Scherlach
- Department of Neuroradiology, University Hospital Leipzig, Liebigstrasse 20, 04103, Leipzig, Germany
| | - Wolfgang Härtig
- Paul Flechsig Institute for Brain Research, University Leipzig, Leipzig, Germany
| | - Stefan Schob
- Department of Neuroradiology, University Hospital Leipzig, Liebigstrasse 20, 04103, Leipzig, Germany.
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8
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Krause M, Peukert N, Härtig W, Emmer A, Mahr CV, Richter C, Dieckow J, Puchta J, Pirlich M, Hoffmann KT, Nestler U, Schob S. Localization, Occurrence, and CSF Changes of SP-G, a New Surface Active Protein with Assumable Immunoregulatory Functions in the CNS. Mol Neurobiol 2018; 56:2433-2439. [PMID: 30032421 DOI: 10.1007/s12035-018-1247-x] [Citation(s) in RCA: 7] [Impact Index Per Article: 1.2] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/08/2018] [Accepted: 07/15/2018] [Indexed: 10/28/2022]
Abstract
Conventional surfactant proteins (A, B, C, and D) are important players of the innate immunity in the central nervous system and serve as effective regulators of cerebrospinal fluid rheology, probably being involved in clearance of detrimental metabolites like beta-amyloid and phospho-tau. Recently, a novel surfactant protein, SP-G, was described in kidneys and peripheral endocrine and exocrine glands. So far, its presence and possible functions in the central nervous system are unknown. Therefore, our study aimed to elucidate the presence of SP-G in the brain and its concentration in normal and pathologic samples of cerebrospinal fluid in order to gain first insight into its regulation and possible functions. A total of 121 samples of human cerebrospinal fluid (30 controls, 60 hydrocephalus patients, 7 central nervous system infections, and 24 brain hemorrhage patients) and 21 rat brains were included in our study. CSF samples were quantified using a commercially available ELISA system. Results were analyzed statistically using SPSS 22, performing Spearman Rho correlation and ANOVA with Dunnett's post hoc analysis. Rat brains were investigated via immunofluorescence to determine SP-G presence and colocalization with common markers like aquaporin-4, glial fibrillary acidic protein, platelet endothelial adhesion molecule 1, and neuronal nuclear antigen. SP-G occurs associated with brain vessels, comparable to other conventional SPs, and is present in a set of cortical neurons. SP-G is furthermore actively produced by ependymal and choroid plexus epithelium and secreted into the cerebrospinal fluid. Its concentrations are low in control subjects and patients suffering from aqueductal stenosis, higher in normal pressure hydrocephalus (p < 0.01), and highest in infections of the central nervous system and brain hemorrhage (p < 0.001). Interestingly, SP-G did correlate with total CSF protein in patients with CNS infections and hemorrhage, but not with cell count. Based on the changes in CSF levels of SP-G in hydrocephalus, brain hemorrhage, and CNS infections as well as its abundance at CSF flow-related anatomical structures closely associated with immunological barrier systems, importance for CSF rheology, brain waste clearance, and host defense is assumable. Thus, SP-G is a potential new CSF biomarker, possibly not only reflecting aspects of CNS innate immune responses, but also rheo-dynamically relevant changes of CSF composition, associated with CSF malabsorbtion. However, further studies are warranted to validate our findings and increase insight into the physiological importance of SP-G in the CNS.
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Affiliation(s)
- Matthias Krause
- Department for Neurosurgery, University Hospital Leipzig, Leipzig, Germany
| | - Nicole Peukert
- Department for Pediatric Surgery, University Hospital Leipzig, Leipzig, Germany
| | - Wolfgang Härtig
- Paul Flechsig Institute for Brain Research, Medical Faculty / University Leipzig, Leipzig, Germany
| | - Alexander Emmer
- Department for Neurology, University Hospital Halle-Wittenberg / Martin Luther University, Halle/Saale, Germany
| | | | - Cindy Richter
- Department for Neuroradiology, University Hospital Leipzig, Liebigstrasse 20, 04103, Leipzig, Germany
| | - Julia Dieckow
- Department for Ophthalmology, University Hospital Leipzig, Leipzig, Germany
| | - Joana Puchta
- Paul Flechsig Institute for Brain Research, Medical Faculty / University Leipzig, Leipzig, Germany.,Department for Neuroradiology, University Hospital Leipzig, Liebigstrasse 20, 04103, Leipzig, Germany
| | - Mandy Pirlich
- Department for Neurology, University Hospital Leipzig, Leipzig, Germany
| | - Karl-Titus Hoffmann
- Department for Neuroradiology, University Hospital Leipzig, Liebigstrasse 20, 04103, Leipzig, Germany
| | - Ulf Nestler
- Department for Neurosurgery, University Hospital Leipzig, Leipzig, Germany
| | - Stefan Schob
- Department for Neuroradiology, University Hospital Leipzig, Liebigstrasse 20, 04103, Leipzig, Germany.
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