scholarly journals Region-Specific Sialylation Pattern of Prion Strains Provides Novel Insight into Prion Neurotropism

2020 ◽  
Vol 21 (3) ◽  
pp. 828 ◽  
Author(s):  
Natallia Makarava ◽  
Jennifer Chen-Yu Chang ◽  
Ilia V. Baskakov
Keyword(s):  
Molecular Mechanisms ◽  
Selective Vulnerability ◽  
Brain Regions ◽  
Dependent Manner ◽  
Infectious Agents ◽  
Prion Infection ◽  
Prion Strains ◽  
Mammalian Prions ◽  
Insight Into ◽  
Host Brain

Mammalian prions are unconventional infectious agents that invade and replicate in an organism by recruiting a normal form of a prion protein (PrPC) and converting it into misfolded, disease-associated state referred to as PrPSc. PrPC is posttranslationally modified with two N-linked glycans. Prion strains replicate by selecting substrates from a large pool of PrPC sialoglycoforms expressed by a host. Brain regions have different vulnerability to prion infection, however, molecular mechanisms underlying selective vulnerability is not well understood. Toward addressing this question, the current study looked into a possibility that sialylation of PrPSc might be involved in defining selective vulnerability of brain regions. The current work found that in 22L -infected animals, PrPSc is indeed sialylated in a region dependent manner. PrPSc in hippocampus and cortex was more sialylated than PrPSc from thalamus and stem. Similar trends were also observed in brain materials from RML- and ME7-infected animals. The current study established that PrPSc sialylation status is indeed region-specific. Together with previous studies demonstrating that low sialylation status accelerates prion replication, this work suggests that high vulnerability of certain brain region to prion infection could be attributed to their low sialylation status.

PRAMEF2-mediated dynamic regulation of YAP signaling promotes tumorigenesis

2021 ◽  
Vol 118 (40) ◽  
pp. e2105523118
Author(s):  
Madhurima Ghosh ◽  
Sanjeev Das
Keyword(s):  
Molecular Mechanisms ◽  
Nuclear Accumulation ◽  
Dependent Manner ◽  
Transcriptional Coactivator ◽  
Dynamic Regulation ◽  
Cancer Testis Antigens ◽  
Ubiquitin Ligase Complex ◽  
Insight Into ◽  
Cancer Testis

PRAMEF2 is a member of the PRAME multigene family of cancer testis antigens, which serve as prognostic markers for several cancers. However, molecular mechanisms underlying its role in tumorigenesis remain poorly understood. Here, we report that PRAMEF2 is repressed under conditions of altered metabolic homeostasis in a FOXP3-dependent manner. We further demonstrate that PRAMEF2 is a BC-box containing substrate recognition subunit of Cullin 2–based E3 ubiquitin ligase complex. PRAMEF2 mediates polyubiquitylation of LATS1 kinase of the Hippo/YAP pathway, leading to its proteasomal degradation. The site for ubiquitylation was mapped to the conserved Lys860 residue in LATS1. Furthermore, LATS1 degradation promotes enhanced nuclear accumulation of the transcriptional coactivator YAP, resulting in increased expression of proliferative and metastatic genes. Thus, PRAMEF2 promotes malignant phenotype in a YAP-dependent manner. Additionally, elevated PRAMEF2 levels correlate with increased nuclear accumulation of YAP in advanced grades of breast carcinoma. These findings highlight the pivotal role of PRAMEF2 in tumorigenesis and provide mechanistic insight into YAP regulation.

Binding between heparin and the integrin VLA-4

2009 ◽  
Vol 102 (11) ◽  
pp. 816-822 ◽  
Author(s):  
Martin Schlesinger ◽  
Dirk Simonis ◽  
Patrick Schmitz ◽  
Juliane Fritzsche ◽  
Gerd Bendas
Keyword(s):  
Molecular Recognition ◽  
Molecular Mechanisms ◽  
Binding Constants ◽  
Dependent Manner ◽  
Heparin Binding ◽  
Promising Therapeutic Approach ◽  
Murine Melanoma Cells ◽  
Insight Into ◽  
Micromolar Range ◽  
Direct Confirmation

SummaryHeparin possesses antimetastatic effects that were related to various molecular mechanisms beyond anticoagulant activities. The ability of heparin to interfere with the function of adhesion receptors in the metastatic course appears as a promising therapeutic approach. This refers to numerous findings that heparin attenuates metastasis in a selectin-dependent manner. We recently demonstrated that heparin interferes with the integrin VLA-4 on murine melanoma cells binding to VCAM-1. To confirm this activity and to obtain further insight into molecular recognition of heparin by VLA-4, we investigated the inhibition of VLA-4 mediated binding of human melanoma MV3 cells to immobilized VCAM-1 by different heparins. The size of heparin has an important impact on inhibition. Unfractionated heparin (UFH) and tinzaparin, a low-molecular-weight heparin (LMWH) representing a mean of about 18– 20 monomers, displayed high inhibitory activity. Fractionating tinzaparin to 14– 18 monomers reduced inhibition slightly, while the pentasaccharide fondaparinux was without effects. To confirm molecular recognition of tinzaparin by VLA-4,a surface acoustic wave-biosensor was applied. A VLA-4 containing membrane preparation of MV3 cells was immobilised at the sensors to allow for detection of kinetic binding constants of tinzaparin compared to VCAM-1. Tinzaparin binds to VLA-4 with affinity in the low micromolar range (4.61× 10−6 M), which clearly indicates specific molecular recognition. Furthermore, tinzaparin displays a nearly identical koff compared toVCAM-1 (5.13× 10−3 s-1 versus 3.44× 10–3 s-1) which is evident for interference with the ligand binding. The data provide evidence for a direct confirmation of heparin binding to VLA-4 and thus, contribute to understand the antimetastatic activity of heparin.

scholarly journals Loss of region-specific glial homeostatic signature in prion diseases

2019 ◽  
Author(s):  
Natallia Makarava ◽  
Jennifer Chen-Yu Chang ◽  
Kara Molesworth ◽  
Ilia V. Baskakov
Keyword(s):  
Gene Expression ◽  
Neurodegenerative Diseases ◽  
Prion Diseases ◽  
Clinical Signs ◽  
Gene Expression Signature ◽  
Brain Regions ◽  
Prion Infection ◽  
Prion Strains ◽  
Advanced Stages ◽  
Disease Region

AbstractBackgroundChronic neuroinflammation is recognized as a major neuropathological hallmark in a broad spectrum of neurodegenerative diseases including Alzheimer’s, Parkinson’s, Frontal Temporal Dementia, Amyotrophic Lateral Sclerosis, and prion diseases. Both microglia and astrocytes exhibit region-specific homeostatic transcriptional identities, which under chronic neurodegeneration, transform into reactive phenotypes in a region- and disease-specific manner. Little is known about region-specific identity of glia in prion diseases. The current study was designed to determine whether the region-specific homeostatic signature of glia changes with the progression of prion diseases, and whether these changes occur in a region-dependent or universal manner. Also of interest was whether different prion strains give rise to different reactive phenotypes.MethodsTo answer these questions, we analyzed gene expression in thalamus, cortex, hypothalamus and hippocampus of mice infected with 22L and ME7 prion strains using Nanostring Neuroinflammation panel at subclinical, early clinical and advanced stages of the disease.ResultsWe found that at the preclinical stage of the disease, region-specific homeostatic identities were preserved. However, with the appearance of clinical signs, region-specific signatures were partially lost and replaced with a neuroinflammation signature. While the same sets of genes were activated by both prion strains, the timing of neuroinflammation and the degree of activation in different brain regions was strain-specific. Changes in astrocyte function scored at the top of activated pathways. Moreover, clustering analysis suggested that the astrocyte function pathway responded to prion infection prior to activated microglia or neuron and neurotransmission pathways.ConclusionsThe current work established neuroinflammation gene expression signature associated with prion diseases. Our results illustrate that with the disease progression, the region-specific homeostatic transcriptome signatures are replaced by region-independent neuroinflammation signature, which was common for prion strains with different cell tropism. The prion-associated neuroinflammation signature identified in the current study overlapped only partially with the microglia degenerative phenotype and the disease-associated microglia phenotype reported for animal models of other neurodegenerative diseases.

scholarly journals Microglia in Health and Disease: The Strength to Be Diverse and Reactive

2021 ◽  
Vol 15 ◽  
Author(s):  
Oihane Uriarte Huarte ◽  
Lorraine Richart ◽  
Michel Mittelbronn ◽  
Alessandro Michelucci
Keyword(s):  
Molecular Mechanisms ◽  
Brain Regions ◽  
Brain Diseases ◽  
Dependent Manner ◽  
Immune Effector ◽  
Effector Cells ◽  
Immune Effector Cells ◽  
The Central Nervous System ◽  
Health And Disease ◽  
Reactive Properties

Microglia are the resident immune effector cells of the central nervous system (CNS) rapidly reacting to any perturbation in order to maintain CNS homeostasis. Although their outstanding reactive properties have been elucidated over the last decades, their heterogeneity in healthy tissue, such as across brain regions, as well as their diversity in the development and progression of brain diseases, are currently opening new avenues to understand the cellular and functional states of microglia subsets in a context-dependent manner. Here, we review the main breakthrough studies that helped in elucidating microglia heterogeneity in the healthy and diseased brain and might pave the way to critical functional screenings of the inferred cellular diversity. We suggest that unraveling the cellular and molecular mechanisms underlying specific functionalities of microglial subpopulations, which may ultimately support or harm the neuronal network in neurodegenerative diseases, or may acquire pro- or anti-tumorigenic phenotypes in brain tumors, will possibly uncover new therapeutic avenues for to date non-curable neurological disorders.

scholarly journals S1PR3 mediates itch and pain via distinct TRP channel-dependent pathways

2017 ◽  
Author(s):  
Rose Z. Hill ◽  
Takeshi Morita ◽  
Rachel B. Brem ◽  
Diana M. Bautista
Keyword(s):  
Molecular Mechanisms ◽  
Dependent Manner ◽  
Cellular Mechanisms ◽  
Concentration Dependent Manner ◽  
Major Health ◽  
Sphingosine 1 Phosphate ◽  
Low Levels ◽  
Channel Dependent ◽  
Behavioral Assays ◽  
Insight Into

AbstractSphingosine 1-phosphate (S1P) is a bioactive signaling lipid associated with a variety of chronic pain and itch disorders. S1P signaling has been linked to cutaneous pain, but its role in itch has not yet been studied. Here we find that S1P triggers itch and pain in mice in a concentration-dependent manner, with low levels triggering acute itch alone, and high levels triggering both pain and itch. Calcium imaging and electrophysiological experiments revealed that S1P signals via S1PR3 and TRPA1 in a subset of pruriceptors, and via S1PR3 and TRPV1 in a subset of heat nociceptors. And in behavioral assays, S1P-evoked itch was selectively lost in mice lacking TRPA1, whereas S1P-evoked acute pain and heat hypersensitivity were selectively lost in mice lacking TRPV1. We conclude that S1P acts via different cellular and molecular mechanisms to trigger itch and pain. Our discovery elucidates the diverse roles that S1P signaling plays in somatosensation and provides insight into how itch and pain are discriminated in the periphery.Significance StatementItch and pain are major health problems with few effective treatments. Here, we show that the pro-inflammatory lipid S1P and its receptor S1PR3 trigger itch and pain behaviors via distinct molecular and cellular mechanisms. Our results provide a detailed understanding of the roles that S1P and S1PR3 play in somatosensation, highlighting their potential as targets for analgesics and antipruritics, and provide new insight into the mechanistic underpinnings of itch versus pain discrimination in the periphery.

scholarly journals Loss of region-specific glial homeostatic signature in prion diseases

2019 ◽  
Author(s):  
Natallia Makarava ◽  
Jennifer Chen-Yu Chang ◽  
Kara Molesworth ◽  
Ilia V Baskakov
Keyword(s):  
Gene Expression ◽  
Neurodegenerative Diseases ◽  
Prion Diseases ◽  
Clinical Signs ◽  
Gene Expression Signature ◽  
Brain Regions ◽  
Prion Infection ◽  
Prion Strains ◽  
Advanced Stages ◽  
Disease Region

Abstract Background Chronic neuroinflammation is recognized as a major neuropathological hallmark in a broad spectrum of neurodegenerative diseases including Alzheimer’s, Parkinson’s, Frontal Temporal Dementia, Amyotrophic Lateral Sclerosis, and prion diseases. Both microglia and astrocytes exhibit region-specific homeostatic transcriptional identities, which under chronic neurodegeneration, transform into reactive phenotypes in a region- and disease-specific manner. Little is known about region-specific identity of glia in prion diseases. The current study was designed to determine whether the region-specific homeostatic signature of glia changes with the progression of prion diseases, and whether these changes occur in a region-dependent or universal manner. Also of interest was whether different prion strains give rise to different reactive phenotypes. Methods To answer these questions, we analyzed gene expression in thalamus, cortex, hypothalamus and hippocampus of mice infected with 22L and ME7 prion strains using Nanostring Neuroinflammation panel at subclinical, early clinical and advanced stages of the disease. Results We found that at the preclinical stage of the disease, region-specific homeostatic identities were preserved. However, with the appearance of clinical signs, region-specific signatures were partially lost and replaced with a neuroinflammation signature. While the same sets of genes were activated by both prion strains, the timing of neuroinflammation and the degree of activation in different brain regions was strain-specific. Changes in astrocyte function scored at the top of activated pathways. Moreover, clustering analysis suggested that the astrocyte function pathway responded to prion infection prior to activated microglia or neuron and neurotransmission pathways. Conclusions The current work established neuroinflammation gene expression signature associated with prion diseases. Our results illustrate that with the disease progression, the region-specific homeostatic transcriptome signatures are replaced by region-independent neuroinflammation signature, which was common for prion strains with different cell tropism. The prion-associated neuroinflammation signature identified in the current study overlapped only partially with the microglia degenerative phenotype and the disease-associated microglia phenotype reported for animal models of other neurodegenerative diseases.

scholarly journals All the Same? The Secret Life of Prion Strains within Their Target Cells

Viruses ◽  
2019 ◽  
Vol 11 (4) ◽  
pp. 334 ◽  
Author(s):  
Ina M. Vorberg
Keyword(s):  
Cell Lines ◽  
Cell Biology ◽  
Brain Regions ◽  
Target Cells ◽  
Genetic Manipulations ◽  
Disease Phenotypes ◽  
Prion Strains ◽  
Quaternary Structures ◽  
Β Sheet ◽  
Insight Into

Prions are infectious β-sheet-rich protein aggregates composed of misfolded prion protein (PrPSc) that do not possess coding nucleic acid. Prions replicate by recruiting and converting normal cellular PrPC into infectious isoforms. In the same host species, prion strains target distinct brain regions and cause different disease phenotypes. Prion strains are associated with biophysically distinct PrPSc conformers, suggesting that strain properties are enciphered within alternative PrPSc quaternary structures. So far it is unknown how prion strains target specific cells and initiate productive infections. Deeper mechanistic insight into the prion life cycle came from cell lines permissive to a range of different prion strains. Still, it is unknown why certain cell lines are refractory to infection by one strain but permissive to another. While pharmacologic and genetic manipulations revealed subcellular compartments involved in prion replication, little is known about strain-specific requirements for endocytic trafficking pathways. This review summarizes our knowledge on how prions replicate within their target cells and on strain-specific differences in prion cell biology.

scholarly journals Aggregation pathways of human γ D crystallin induced by metal ions revealed by time dependent methods

PeerJ ◽  
2020 ◽  
Vol 8 ◽  
pp. e9178
Author(s):  
Arline Fernández-Silva ◽  
Leidys French-Pacheco ◽  
Lina Rivillas-Acevedo ◽  
Carlos Amero
Keyword(s):  
Molecular Mechanisms ◽  
Copper Ions ◽  
Dependent Manner ◽  
Cataract Formation ◽  
Temperature Dependent ◽  
Terminal Domain ◽  
Equilibrium Process ◽  
Partially Unfolded ◽  
Induced Aggregation ◽  
Insight Into

Cataract formation is a slow accumulative process due to protein aggregates promoted by different factors over time. Zinc and copper ions have been reported to induce the formation of aggregates opaque to light in the human gamma D crystallin (HγD) in a concentration and temperature dependent manner. In order to gain insight into the mechanism of metal-induced aggregation of HγD under conditions that mimic more closely the slow, accumulative process of the disease, we have studied the non-equilibrium process with the minimal metal dose that triggers HγD aggregation. Using a wide variety of biophysics techniques such as turbidimetry, dynamic light scattering, fluorescence, nuclear magnetic resonance and computational methods, we obtained information on the molecular mechanisms for the formation of aggregates. Zn(II) ions bind to different regions at the protein, probably with similar affinities. This binding induces a small conformational rearrangement within and between domains and aggregates via the formation of metal bridges without any detectable unfolded intermediates. In contrast, Cu(II)-induced aggregation includes a lag time, in which the N-terminal domain partially unfolds while the C-terminal domain and parts of the N-terminal domain remain in a native-like conformation. This partially unfolded intermediate is prone to form the high-molecular weight aggregates. Our results clearly show that different external factors can promote protein aggregation following different pathways.

scholarly journals Longevity-Extending MetAP2 Inhibitors Induce Caloric Restriction Through P53-Dependent Induction of GDF-15

2020 ◽  
Vol 4 (Supplement_1) ◽  
pp. 125-126
Author(s):  
Michael MacArthur ◽  
Sarah Mitchell ◽  
Jon Jung ◽  
Margaret Torrence ◽  
Alice Kane ◽  
...  
Keyword(s):  
Food Intake ◽  
Molecular Mechanisms ◽  
Ex Vivo ◽  
Brain Regions ◽  
Target Tissue ◽  
Dependent Manner ◽  
P53 Signaling ◽  
P53 Activation ◽  
Visceral Adipose

Abstract MetAP2 is a 67kDa protein which sits at the translation initiation complex and cleaves N-terminal methionine off of nascent peptides. Inhibitors of MetAP2 cause profound weight loss secondary to decreased food intake. These inhibitors also significantly extend longevity in mice in late-life intervention. However, the exact mechanism of action causing decreased food intake is not known. Here we investigated the molecular mechanism and target tissue of a MetAP2 inhibitor’s (Zgn1062) anorectic effects. First we identified the target tissue by testing targeted Zgn1062 delivery to specific brain regions. Delivery to the medio-basal hypothalamus did not have a significant effect but delivery to the lateral ventricle resulted in significantly decrease food intake and body weight after 2 and 14 hours. When we delivered a neuron-targeted AAV encoding MetAP2 shRNA we saw decreased efficacy of MetAP2 confirming the required for neuronal MetAP2 for anorectic effects. To determine the molecular mechanisms we performed RNAseq of wildtype and MetAP2 KO HT1080 cells across a timecourse of Zgn1062 treatment. The main pathway activated across timepoints in MetAP2-dependent manner was P53 signaling. A main P53 target that was upregulated was the known anorectic peptide GDF15. We confirmed GDF15 increases in vivo at both mRNA (liver and intestines) and protein level (serum) in response to Zgn1062. We also found that Zgn1062 treatment reduces senescent cell burden in visceral adipose tissue in vivo and reduces SASP gene expression in fat explants ex vivo. We hypothesize that Zgn1062’s potent P53 activation may play a role in clearance of senescent cells.

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