scholarly journals Roles for α-Synuclein in Gene Expression

Genes ◽  
2021 ◽  
Vol 12 (8) ◽  
pp. 1166
Author(s):  
Mahalakshmi Somayaji ◽  
Zina Lanseur ◽  
Se Joon Choi ◽  
David Sulzer ◽  
Eugene V. Mosharov
Keyword(s):  
Gene Expression ◽  
Physiological Role ◽  
Function Mechanism ◽  
Normal Functions ◽  
Presynaptic Function ◽  
Dependent Signal ◽  
Expression Pathways ◽  
Cellular Compartments ◽  
Activity Dependent ◽  
Familial Parkinson’S Disease

α-Synuclein (α-Syn) is a small cytosolic protein associated with a range of cellular compartments, including synaptic vesicles, the nucleus, mitochondria, endoplasmic reticulum, Golgi apparatus, and lysosomes. In addition to its physiological role in regulating presynaptic function, the protein plays a central role in both sporadic and familial Parkinson’s disease (PD) via a gain-of-function mechanism. Because of this, several recent strategies propose to decrease α-Syn levels in PD patients. While these therapies may offer breakthroughs in PD management, the normal functions of α-Syn and potential side effects of its depletion require careful evaluation. Here, we review recent evidence on physiological and pathological roles of α-Syn in regulating activity-dependent signal transduction and gene expression pathways that play fundamental role in synaptic plasticity.

scholarly journals Activity-dependent bulk endocytosis proteome reveals a key presynaptic role for the monomeric GTPase Rab11

2018 ◽  
Vol 115 (43) ◽  
pp. E10177-E10186 ◽  
Author(s):  
A. C. Kokotos ◽  
J. Peltier ◽  
E. C. Davenport ◽  
M. Trost ◽  
M. A. Cousin
Keyword(s):  
Physiological Role ◽  
Bioinformatic Analysis ◽  
Subcellular Fractionation ◽  
Dominant Mode ◽  
High Frequency Stimulation ◽  
Rab Gtpases ◽  
Subsequent Investigation ◽  
Presynaptic Function ◽  
Core Proteome ◽  
Activity Dependent

Activity-dependent bulk endocytosis (ADBE) is the dominant mode of synaptic vesicle endocytosis during high-frequency stimulation, suggesting it should play key roles in neurotransmission during periods of intense neuronal activity. However, efforts in elucidating the physiological role of ADBE have been hampered by the lack of identified molecules which are unique to this endocytosis mode. To address this, we performed proteomic analysis on purified bulk endosomes, which are a key organelle in ADBE. Bulk endosomes were enriched via two independent approaches, a classical subcellular fractionation method and isolation via magnetic nanoparticles. There was a 77% overlap in proteins identified via the two protocols, and these molecules formed the ADBE core proteome. Bioinformatic analysis revealed a strong enrichment in cell adhesion and cytoskeletal and signaling molecules, in addition to expected synaptic and trafficking proteins. Network analysis identified Rab GTPases as a central hub within the ADBE proteome. Subsequent investigation of a subset of these Rabs revealed that Rab11 both facilitated ADBE and accelerated clathrin-mediated endocytosis. These findings suggest that the ADBE proteome will provide a rich resource for the future study of presynaptic function, and identify Rab11 as a regulator of presynaptic function.

scholarly journals AAV-Mediated CRISPRi and RNAi Based Gene Silencing in Mouse Hippocampal Neurons

Cells ◽  
2021 ◽  
Vol 10 (2) ◽  
pp. 324
Author(s):  
Matthias Deutsch ◽  
Anne Günther ◽  
Rodrigo Lerchundi ◽  
Christine R. Rose ◽  
Sabine Balfanz ◽  
...  
Keyword(s):  
Gene Expression ◽  
Transcription Initiation ◽  
Hippocampal Neurons ◽  
De Novo ◽  
Protein Biosynthesis ◽  
Physiological Role ◽  
High Specificity ◽  
Hcn Channels ◽  
Proliferating Cells ◽  
Neuronal Tissues

Uncovering the physiological role of individual proteins that are part of the intricate process of cellular signaling is often a complex and challenging task. A straightforward strategy of studying a protein’s function is by manipulating the expression rate of its gene. In recent years, the Clustered Regularly Interspaced Short Palindromic Repeat (CRISPR)/Cas9-based technology was established as a powerful gene-editing tool for generating sequence specific changes in proliferating cells. However, obtaining homogeneous populations of transgenic post-mitotic neurons by CRISPR/Cas9 turned out to be challenging. These constraints can be partially overcome by CRISPR interference (CRISPRi), which mediates the inhibition of gene expression by competing with the transcription machinery for promoter binding and, thus, transcription initiation. Notably, CRISPR/Cas is only one of several described approaches for the manipulation of gene expression. Here, we targeted neurons with recombinant Adeno-associated viruses to induce either CRISPRi or RNA interference (RNAi), a well-established method for impairing de novo protein biosynthesis by using cellular regulatory mechanisms that induce the degradation of pre-existing mRNA. We specifically targeted hyperpolarization-activated and cyclic nucleotide-gated (HCN) channels, which are widely expressed in neuronal tissues and play essential physiological roles in maintaining biophysical characteristics in neurons. Both of the strategies reduced the expression levels of three HCN isoforms (HCN1, 2, and 4) with high specificity. Furthermore, detailed analysis revealed that the knock-down of just a single HCN isoform (HCN4) in hippocampal neurons did not affect basic electrical parameters of transduced neurons, whereas substantial changes emerged in HCN-current specific properties.

274 Tumoral and peripheral immunophenotype of refractory vs relapse to PD-(L)1 blockade in patients with advanced non-small cell lung cancer

2020 ◽  
Vol 8 (Suppl 3) ◽  
pp. A299-A299
Author(s):  
Maria Ascierto ◽  
Matthew Hellmann ◽  
Nathan Standifer ◽  
Song Wu ◽  
Han Si ◽  
...  
Keyword(s):  
Gene Expression ◽  
Informed Consent ◽  
Checkpoint Inhibitors ◽  
Patient Response ◽  
Calcium Dependent ◽  
Immune Exhaustion ◽  
Previously Treated ◽  
Expression Pathways ◽  
Relapsed Disease ◽  
Written Informed Consent

BackgroundDespite the encouraging successes of immune checkpoint inhibitors, many patients do not benefit and are either refractory or relapse. The mechanisms of refractory or relapsed disease following PD-(L)1 blockade are largely unknown. To identify characteristics associated with refractory or relapsed disease we explored the immune and genomic landscape of samples derived from NSCLC patients who previously received PD-(L)1 blockade and had blood and fresh tumor biopsies collected at the time of progression.MethodsPatient response categories were defined prospectively; ‘refractory’ defined as progression within 16 weeks of initiating PD-(L)1 and ‘relapse’ defined as initial clinical benefit (CR, PR, SD) followed by progression. RNAseq (n=52) and PD-L1 IHC (n=22) were performed on tumor tissue. Immune profiling of whole blood was assessed using flow cytometry or Biomark HD (Fluidigm) gene expression panel (n=54 and n=62, respectively). Differential gene expression was defined as unadjusted p<0.05 and fold-difference >1.5. Pathways analysis was conducted by David tool. Patient samples were collected during screening for clinical trial of second line immunotherapy. Written informed consent was obtained from the patients for publication of this abstract.ResultsIn patients with NSCLC previously treated with PD-(L)1 blockade, tumors of relapsed patients were characterized by increased expression of genes associated with interferon signaling (e.g. CXCL9, SPIC, IFNg), immune suppression (e.g. ARG1, TGFB), immune exhaustion (e.g. ADORA2A), and increased PD-L1 expression (by gene expression and IHC). Refractory disease was associated with increased cadherin signaling and calcium-dependent-cell-adhesion gene expression pathways. In the periphery, reduced quantities of B cells and activated (HLA-DR+ or CD38+) or proliferating (Ki67+) CD8+ T cells were observed in refractory patients.ConclusionsThe tumor and peripheral compartments of patients with NSCLC previously treated with PD-(L)1 blockade differ based on prior response. Relapsed patients tend to have signals of sturdy immune activation and chronic inflammation thus ultimately leading to immune exhaustion. These results may help inform rational therapeutic strategies to overcome resistance to PD-(L)1 blockade in NSCLC.Trial RegistrationNCT02000947Ethics ApprovalResearch on human samples here analyzed have been performed in accordance with the Declaration of Helsinki.ConsentWritten informed consent was obtained from the patient for publication of this abstract.

Serial analysis of gene expression (SAGE) during porcine embryo development

2004 ◽  
Vol 16 (2) ◽  
pp. 87 ◽  
Author(s):  
Le Ann Blomberg ◽  
Kurt A. Zuelke
Keyword(s):  
Gene Expression ◽  
Functional Genomics ◽  
Embryo Development ◽  
Molecular Mechanisms ◽  
Physiological Role ◽  
Transgenic Animals ◽  
Specific Gene ◽  
Research Strategies

Functional genomics provides a powerful means for delving into the molecular mechanisms involved in pre-implantation development of porcine embryos. High rates of embryonic mortality (30%), following either natural mating or artificial insemination, emphasise the need to improve the efficiency of reproduction in the pig. The poor success rate of live offspring from in vitro-manipulated pig embryos also hampers efforts to generate transgenic animals for biotechnology applications. Previous analysis of differential gene expression has demonstrated stage-specific gene expression for in vivo-derived embryos and altered gene expression for in vitro-derived embryos. However, the methods used to date examine relatively few genes simultaneously and, thus, provide an incomplete glimpse of the physiological role of these genes during embryogenesis. The present review will focus on two aspects of applying functional genomics research strategies for analysing the expression of genes during elongation of pig embryos between gestational day (D) 11 and D12. First, we compare and contrast current methodologies that are being used for gene discovery and expression analysis during pig embryo development. Second, we establish a paradigm for applying serial analysis of gene expression as a functional genomics tool to obtain preliminary information essential for discovering the physiological mechanisms by which distinct embryonic phenotypes are derived.

GABA induces activity-dependent gene expression in immature cortical cell culture

2011 ◽  
Vol 71 ◽  
pp. e114
Author(s):  
Atsumi Mori ◽  
Mamoru Fukuchi ◽  
Yuya Kirikoshi ◽  
Ichiro Takasaki ◽  
Aiko Azegami ◽  
...  
Keyword(s):  
Gene Expression ◽  
Cell Culture ◽  
Cortical Cell ◽  
Activity Dependent

Antioxidants increase number of progenitor endothelial cells through multiple gene expression pathways

2008 ◽  
Vol 42 (8) ◽  
pp. 754-762 ◽  
Author(s):  
Carmela Fiorito ◽  
Monica Rienzo ◽  
Ettore Crimi ◽  
Raffaele Rossiello ◽  
Maria Luisa Balestrieri ◽  
...  
Keyword(s):  
Gene Expression ◽  
Endothelial Cells ◽  
Multiple Gene ◽  
Expression Pathways

Retargeting of the mitochondrial protein p32/gC1Qr to a cytoplasmic compartment and the cell surface

2001 ◽  
Vol 114 (11) ◽  
pp. 2115-2123
Author(s):  
Hans C. van Leeuwen ◽  
Peter O’Hare
Keyword(s):  
Cell Surface ◽  
Protein Interactions ◽  
Mitochondrial Protein ◽  
Physiological Role ◽  
Surface Expression ◽  
Transport Processes ◽  
Cell Surface Expression ◽  
Bacterial Proteins ◽  
Er Chaperone ◽  
Cellular Compartments

p32/gC1qR is a small acidic protein that has been reported to have a broad range of distinct functions and to associate with a wide array of cellular, viral and bacterial proteins. It has been found in each of the main cellular compartments including mitochondria, nucleus and cytoplasm and is also thought to be located at the plasma membrane and secreted into the extracellular matrix. The true physiological role(s) of p32 remains controversial because it has been difficult to reconcile all of the findings on protein interactions and the seemingly disparate observations on compartmentalisation. However, it has been proposed that p32 is somehow involved in transport processes connecting diverse cellular compartments and the cell surface. Here we show that native p32 appears to be localised mainly in the mitochondria and is not detectable on the cell surface. However, addition of a short tag to the N-terminus of p32 appears to block its mitochondrial targeting, resulting in redirection into a cytoplasmic vesicular pattern, overlapping with the endoplasmic reticulum. The redirection of p32 results in an alteration in and co-localisation with ER markers including calreticulin, a lumenal ER chaperone. Furthermore, we show both by immunofluorescence and cross-linking studies that this also results in cell-surface expression of p32. These results indicate that, at least under certain circumstances, p32 can be retargeted and may help to provide an explanation for the diverse observations on its localization.

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