scholarly journals The MAPK/ERK Pathway and the Role of DUSP1 in JCPyV Infection of Primary Astrocytes

Viruses ◽  
2021 ◽  
Vol 13 (9) ◽  
pp. 1834
Author(s):  
Michael P. Wilczek ◽  
Francesca J. Armstrong ◽  
Remi P. Geohegan ◽  
Colleen L. Mayberry ◽  
Jeanne K. DuShane ◽  
...  
Keyword(s):  
Demyelinating Disease ◽  
Cell Model ◽  
Cell Types ◽  
Mitogen Activated Protein Kinase ◽  
Erk Pathway ◽  
Human Astrocytes ◽  
Successful Infection ◽  
Primary Astrocytes ◽  
Underlying Mechanisms ◽  
Immortalized Cell

JC polyomavirus (JCPyV) is a neuroinvasive pathogen causing a fatal, demyelinating disease of the central nervous system (CNS) known as progressive multifocal leukoencephalopathy (PML). Within the CNS, JCPyV predominately targets two cell types: oligodendrocytes and astrocytes. The underlying mechanisms of astrocytic infection are poorly understood, yet recent findings suggest critical differences in JCPyV infection of primary astrocytes compared to a widely studied immortalized cell model. RNA sequencing was performed in primary normal human astrocytes (NHAs) to analyze the transcriptomic profile that emerges during JCPyV infection. Through a comparative analysis, it was validated that JCPyV requires the mitogen-activated protein kinase, extracellular signal-regulated kinase (MAPK/ERK) pathway, and additionally requires the expression of dual-specificity phosphatases (DUSPs). Specifically, the expression of DUSP1 is needed to establish a successful infection in NHAs, yet this was not observed in an immortalized cell model of JCPyV infection. Additional analyses demonstrated immune activation uniquely observed in NHAs. These results support the hypothesis that DUSPs within the MAPK/ERK pathway impact viral infection and influence potential downstream targets and cellular pathways. Collectively, this research implicates DUSP1 in JCPyV infection of primary human astrocytes, and most importantly, further resolves the signaling events that lead to successful JCPyV infection in the CNS.

scholarly journals JCPyV-Induced MAPK Signaling Activates Transcription Factors during Infection

2019 ◽  
Vol 20 (19) ◽  
pp. 4779 ◽  
Author(s):  
Jeanne K. DuShane ◽  
Colleen L. Mayberry ◽  
Michael P. Wilczek ◽  
Sarah L. Nichols ◽  
Melissa S. Maginnis
Keyword(s):  
Transcription Factors ◽  
Mapk Signaling ◽  
Mapk Cascade ◽  
Mitogen Activated Protein Kinase ◽  
Erk Pathway ◽  
Downstream Signaling ◽  
Dual Specificity ◽  
Extracellular Signal ◽  
Mitogen Activated Protein ◽  
Underlying Mechanisms

JC polyomavirus (JCPyV), a ubiquitous human pathogen, is the etiological agent of the fatal neurodegenerative disease progressive multifocal leukoencephalopathy (PML). Like most viruses, JCPyV infection requires the activation of host-cell signaling pathways in order to promote viral replication processes. Previous works have established the necessity of the extracellular signal-regulated kinase (ERK), the terminal core kinase of the mitogen-activated protein kinase (MAPK) cascade (MAPK-ERK) for facilitating transcription of the JCPyV genome. However, the underlying mechanisms by which the MAPK-ERK pathway becomes activated and induces viral transcription are poorly understood. Treatment of cells with siRNAs specific for Raf and MAP kinase kinase (MEK) targets proteins in the MAPK-ERK cascade, significantly reducing JCPyV infection. MEK, the dual-specificity kinase responsible for the phosphorylation of ERK, is phosphorylated at times congruent with early events in the virus infectious cycle. Moreover, a MAPK-specific signaling array revealed that transcription factors downstream of the MAPK cascade, including cMyc and SMAD4, are upregulated within infected cells. Confocal microscopy analysis demonstrated that cMyc and SMAD4 shuttle to the nucleus during infection, and nuclear localization is reduced when ERK is inhibited. These findings suggest that JCPyV induction of the MAPK-ERK pathway is mediated by Raf and MEK and leads to the activation of downstream transcription factors during infection. This study further defines the role of the MAPK cascade during JCPyV infection and the downstream signaling consequences, illuminating kinases as potential therapeutic targets for viral infection.

scholarly journals Lipidomics profiling of goose granulosa cell model of stearoyl-CoA desaturase function identifies a pattern of lipid droplets associated with follicle development

2021 ◽  
Vol 11 (1) ◽  
Author(s):  
Xin Yuan ◽  
Shenqiang Hu ◽  
Liang Li ◽  
Chunchun Han ◽  
Hehe Liu ◽  
...  
Keyword(s):  
Differentially Expressed Genes ◽  
Lipid Droplets ◽  
Cell Model ◽  
Enrichment Analysis ◽  
Differentially Expressed ◽  
Pathway Enrichment Analysis ◽  
Follicle Development ◽  
Microscopy Analysis ◽  
Stearoyl Coa Desaturase ◽  
Underlying Mechanisms

Abstract Background Despite their important functions and nearly ubiquitous presence in cells, an understanding of the biology of intracellular lipid droplets (LDs) in goose follicle development remains limited. An integrated study of lipidomic and transcriptomic analyses was performed in a cellular model of stearoyl-CoA desaturase (SCD) function, to determine the effects of intracellular LDs on follicle development in geese. Results Numerous internalized LDs, which were generally spherical in shape, were dispersed throughout the cytoplasm of granulosa cells (GCs), as determined using confocal microscopy analysis, with altered SCD expression affecting LD content. GC lipidomic profiling showed that the majority of the differentially abundant lipid classes were glycerophospholipids, including PA, PC, PE, PG, PI, and PS, and glycerolipids, including DG and TG, which enriched glycerophospholipid, sphingolipid, and glycerolipid metabolisms. Furthermore, transcriptomics identified differentially expressed genes (DEGs), some of which were assigned to lipid-related Gene Ontology slim terms. More DEGs were assigned in the SCD-knockdown group than in the SCD-overexpression group. Integration of the significant differentially expressed genes and lipids based on pathway enrichment analysis identified potentially targetable pathways related to glycerolipid/glycerophospholipid metabolism. Conclusions This study demonstrated the importance of lipids in understanding follicle development, thus providing a potential foundation to decipher the underlying mechanisms of lipid-mediated follicle development.

scholarly journals Glucose regulates AMP-activated protein kinase activity and gene expression in clonal, hypothalamic neurons expressing proopiomelanocortin: additive effects of leptin or insulin

2007 ◽  
Vol 192 (3) ◽  
pp. 605-614 ◽  
Author(s):  
Fang Cai ◽  
Armen V Gyulkhandanyan ◽  
Michael B Wheeler ◽  
Denise D Belsham
Keyword(s):  
Protein Kinase ◽  
Energy Homeostasis ◽  
Cell Model ◽  
Neuronal Cell ◽  
Cell Types ◽  
Glucose Sensing ◽  
Protein Kinase Activity ◽  
Energy Status ◽  
Ampk Activity ◽  
Amp Activated Protein Kinase

The mammalian hypothalamus comprises an array of phenotypically distinct cell types that interpret peripheral signals of energy status and, in turn, elicits an appropriate response to maintain energy homeostasis. We used a clonal representative hypothalamic cell model expressing proopiomelanocortin (POMC; N-43/5) to study changes in AMP-activated protein kinase (AMPK) activity and glucose responsiveness. We have demonstrated the presence of cellular machinery responsible for glucose sensing in the cell line, including glucokinase, glucose transporters, and appropriate ion channels. ATP-sensitive potassium channels were functional and responded to glucose. The N-43/5 POMC neurons may therefore be an appropriate cell model to study glucose-sensing mechanisms in the hypothalamus. In N-43/5 POMC neurons, increasing glucose concentrations decreased phospho-AMPK activity. As a relevant downstream effect, we found that POMC transcription increased with 2.8 and 16.7 mM glucose. Upon addition of leptin, with either no glucose or with 5 mM glucose, we found that leptin decreased AMPK activity in N-43/5 POMC neurons, but had no significant effect at 25 mM glucose, whereas insulin decreased AMPK activity at only 5 mM glucose. These results demonstrate that individual hypothalamic neuronal cell types, such as the POMC neuron, can have distinct responses to peripheral signals that relay energy status to the brain, and will therefore be activated uniquely to control neuroendocrine function.

LncRNA Prostate Cancer Gene Expression Marker 1 (PCGEM1) Down-Regulation Inhibits the Development of Osteoarthritis by Modulating miR-152-3p

2022 ◽  
Vol 12 (2) ◽  
pp. 306-315
Author(s):  
Jie Song ◽  
Cheng Chen ◽  
Hui Zhang
Keyword(s):  
Cell Model ◽  
Luciferase Reporter ◽  
Down Regulation ◽  
Protein Levels ◽  
Diphenyltetrazolium Bromide ◽  
Proliferation And Apoptosis ◽  
Underlying Mechanisms ◽  
Commercial Kits ◽  
Related Proteins

Osteoarthritis (OA) is a chronic and inflammatory disease, leading to pain or even disability in severe cases. LncRNA PCGEM1 (PCGEM1) is reported to be dysregulated, serving as critical regulators in various human diseases, including OA. However, the biological role of PCGEM1 and its underlying mechanisms during OA remained unclear. In the present study, CHON-001 cells were exposed to interleukin (IL)-1β to construct the OA cell model. Expression of PCGEM1 and miR-152-3p in cells was determined by quantitative real-time polymerase chain reaction (qRT-PCR) assay. Corresponding commercial kits were used to measure the expressions of lactate dehydrogenase (LDH), inter-leukin (IL)-6, IL-8, and tumor necrosis factor (TNF)-α. Protein levels of apoptosis-related proteins, cleaved-Caspase3 and Caspase3, were detected by Western blotting. 3-(4, 5-dimethylthiazol-2-yl)-2, 5-diphenyltetrazolium bromide) tetrazolium (MTT) and flow cytometry assays were utilized for the determination of cell proliferation and apoptosis. The association between PCGEN1 and miR-152-3p was confirmed by a dual-luciferase reporter assay. From the results, PCGEM1 expression was significantly increased while miR-152-3p was inhibited in CHON-001 cells after IL-1β treatment. In addition, silencing of PCGEM1 could promote proliferation, inhibit the apoptosis, suppress LDH level and alleviate inflammation response caused by IL-1β in CHON-001 cells by sponging miR-152-3p. In a word, PCGEM1 down-regulation suppressed OA progression by the regulation of miR-152-3p expression, functioning as a potential therapeutic target for OA clinical treatment.

Potential Mechanisms of miR-143/Krupple Like Factor 5 Axis in Impeding the Proliferation of Michigan Cancer Foundation-7 Breast Cancer Cell Line

2021 ◽  
Vol 11 (2) ◽  
pp. 326-332
Author(s):  
Le Ma ◽  
Zhenyu Liu ◽  
Zhimin Fan
Keyword(s):  
Breast Cancer ◽  
Cancer Cells ◽  
Cancer Cell ◽  
Breast Cancer Cell ◽  
Breast Cancer Cells ◽  
Cell Model ◽  
Cancer Cell Line ◽  
Breast Cancer Cell Model ◽  
Underlying Mechanisms ◽  
Mcf 7

Breast cancer is one of the most prevailing cancers in females, while the cancerous heterogeneity hinders its early diagnosis and subsequent therapy. miR-143-3p is a critical mediator in malignancy development and tumorigenesis as a tumor suppressor. Its role in various tumor entities has been investigated, such as colon cancer and breast cancer. Using MCF-7 breast cancer cell model, we planned to explore the underlying mechanisms of miR-143/KLF-5 axis in retarding breast cancer cells growth. Bioinformatics analysis searched the target KLF5 of miR-143, and the miR-143-targeted mimic and inhibitor were employed to detect the changes of KLF5. After transfection of mimic miR-143, the CCK-8 reagent assessed cell proliferation. Based on optimal stimulation time, miR-143 stimulation model was established, followed by determining expression of KLF5, EGFR and PCNA via western blot and qPCR. Eventually, siRNA-KLF5 was applied to silencing KLF5 level to evaluate its role in MCF-7 cells. The transcription and translation levels of KLF5 were diminished in miR-143-mimic transfected MCF-7 cells, while enhanced in miR-143-inhibitor transfected MCF-7 cells. When MCF-7 cells were transfected with miR-143-mimic at different time points, 48 hours was found to be the optimal transfection time, with reduced transcription and translation levels of KLF5, EGFR and PCNA. The transcription and translation levels of PNCA and EGFR were declined after silencing KLF5 by siRNA. miR-143/KLF5 axis could retard the proliferation of MCF-7 breast cancer cells.

gp120-induced alterations of human astrocyte function: Na+/H+exchange, K+conductance, and glutamate flux

2000 ◽  
Vol 279 (3) ◽  
pp. C700-C708 ◽  
Author(s):  
Holly K. Patton ◽  
Zhen-Hong Zhou ◽  
James K. Bubien ◽  
Etty N. Benveniste ◽  
Dale J. Benos
Keyword(s):  
Glutamate Uptake ◽  
Cell Types ◽  
Neurological Complications ◽  
Ph Sensitive ◽  
Human Astrocyte ◽  
Physiological Processes ◽  
Human Astrocytes ◽  
Rat Astrocytes ◽  
Immunodeficiency Syndrome ◽  
Intracellular Alkalinization

Many human immunodeficiency virus (HIV)-infected patients suffer from impaired neurological function and dementia. This facet of the disease has been termed acquired immunodeficiency syndrome (AIDS)-associated dementia complex (ADC). Several cell types, including astrocytes and neurons, are not productively infected by virus but are involved in ADC pathophysiology. Previous studies of rat astrocytes showed that an HIV coat protein (gp120) accelerated astrocyte Na+/H+exchange and that the resultant intracellular alkalinization activated a pH-sensitive K+conductance. The present experiments were conducted to determine whether gp120 affected human astrocytes in the same fashion. It was found that primary human astrocytes express a pH-sensitive K+conductance that was activated on intracellular alkalinization. Also, gp120 treatment of whole cell clamped human astrocytes activated this conductance specifically. Furthermore, gp120 inhibited glutamate uptake by primary human astrocytes. These altered physiological processes could contribute to pathophysiological changes in HIV-infected brains. Because the gp120-induced cell physiological changes were partially inhibited by dimethylamiloride (an inhibitor of Na+/H+exchange), our findings suggest that modification of human astrocyte Na+/H+exchange activity may provide a means of addressing some of the neurological complications of HIV infection.

scholarly journals Selective expression of the scaffold protein JSAP1 in spermatogonia and spermatocytes

Reproduction ◽  
2006 ◽  
Vol 131 (4) ◽  
pp. 711-719 ◽  
Author(s):  
Munkhuu Bayarsaikhan ◽  
Akiko Shiratsuchi ◽  
Davaakhuu Gantulga ◽  
Yoshinobu Nakanishi ◽  
Katsuji Yoshioka
Keyword(s):  
Protein Kinase ◽  
Western Blotting ◽  
Cell Types ◽  
Mapk Signaling ◽  
Scaffold Protein ◽  
Mitogen Activated Protein Kinase ◽  
Interacting Protein ◽  
Early Postnatal Development ◽  
Mitogen Activated Protein ◽  
Signaling Modules

Scaffold proteins of mitogen-activated protein kinase (MAPK) intracellular signal transduction pathways mediate the efficient and specific activation of the relevant MAPK signaling modules. Previously, our group and others have identified c-Jun NH2-terminal kinase (JNK)/stress-activated protein kinase-associated protein 1 (JSAP1, also known as JNK-interacting protein 3) as a scaffold protein for JNK MAPK pathways. Although JSAP1 is expressed in the testis in adults, its expression during development has not been investigated. In addition, it is unknown which types of cells in the testis express the scaffold protein. Here, we examined the expression of JSAP1 in the testis of mice aged 14 days, 20 days, 6 weeks, and 12 weeks by immunohistochemistry and Western blotting. The specificity of the anti-JSAP1 antibody was evaluated from its reactivity to exogenously expressed JSAP1 and a structurally related protein, and by antigen-absorption experiments. The immunohistochemical analyses with the specific antibody showed that the JSAP1 protein was selectively expressed in the spermatogonia and spermatocytes, but not in other cell types, including spermatids and somatic cells, during development. However, not all spermatogonia and spermatocytes were immunopositive either, especially in the 12-week-old mouse testis. Furthermore, we found by Western blotting that the expression levels of JSAP1 protein vary during development; there is high expression until 6 weeks after birth, which approximately corresponds to the end of the first wave of spermatogenesis. Collectively, these results suggest that JSAP1 function may be important in spermatogenic cells during early postnatal development.

Na-K-Cl cotransport regulates intracellular volume and monolayer permeability of trabecular meshwork cells

1995 ◽  
Vol 268 (4) ◽  
pp. C1067-C1074 ◽  
Author(s):  
M. E. O'Donnell ◽  
J. D. Brandt ◽  
F. R. Curry
Keyword(s):  
Trabecular Meshwork ◽  
Ethacrynic Acid ◽  
Vascular Endothelial Cells ◽  
Critical Role ◽  
Cell Types ◽  
Cell Monolayers ◽  
Aqueous Humor Outflow ◽  
Trabecular Meshwork Cells ◽  
Intracellular Volume ◽  
Underlying Mechanisms

The trabecular meshwork (TM) of the eye plays a critical role in modulating intraocular pressure (IOP) through regulation of aqueous humor outflow, although the underlying mechanisms remain unknown. Ethacrynic acid, an agent known to inhibit Na-K-Cl cotransport of a number of cell types, recently has been reported to increase aqueous outflow and lower IOP through an unknown effect on the TM. In vascular endothelial cells and a variety of other cell types, the Na-K-Cl cotransporter functions to regulate intracellular volume. The present study was conducted to evaluate TM cells for the presence of Na-K-Cl cotransport activity and to test the hypothesis that modulation of cotransport activity alters intracellular volume and, consequently, permeability of the TM. We demonstrate here that bovine and human TM cells exhibit robust Na-K-Cl cotransport activity that is inhibited by bumetanide and by ethacrynic acid. Our studies also show that TM cell Na-K-Cl cotransport is modulated by a variety of hormones and neurotransmitters. Inhibition of the cotransporter either by bumetanide, ethacrynic acid, or inhibitory hormones reduces TM intracellular volume, whereas stimulatory hormones increase cell volume. In addition, shrinkage of the cells by hypertonic media stimulates cotransport activity and initiates a subsequent regulatory volume increase. Permeability of TM cell monolayers, assessed as transmonolayer flux of [14C]sucrose, is increased by hypertonicity-induced cell shrinkage and by bumetanide. These findings suggest that Na-K-Cl cotransport of TM cells is of central importance to regulation of intracellular volume and TM permeability. Defects of Na-K-Cl cotransport may underlie the pathophysiology of glaucoma.

scholarly journals Multiphoton NAD(P)H FLIM reveals metabolic changes in individual cell types of the intact cochlea upon sensorineural hearing loss

2019 ◽  
Vol 9 (1) ◽  
Author(s):  
Paromita Majumder ◽  
Thomas S. Blacker ◽  
Lisa S. Nolan ◽  
Michael R. Duchen ◽  
Jonathan E. Gale
Keyword(s):  
Oxidative Stress ◽  
Hearing Loss ◽  
Cell Model ◽  
Organ Of Corti ◽  
Cell Types ◽  
Fluorescence Lifetime Imaging ◽  
Noise Induced Hearing Loss ◽  
Label Free ◽  
Age Related ◽  
The Individual

AbstractAn increasing volume of data suggests that changes in cellular metabolism have a major impact on the health of tissues and organs, including in the auditory system where metabolic alterations are implicated in both age-related and noise-induced hearing loss. However, the difficulty of access and the complex cyto-architecture of the organ of Corti has made interrogating the individual metabolic states of the diverse cell types present a major challenge. Multiphoton fluorescence lifetime imaging microscopy (FLIM) allows label-free measurements of the biochemical status of the intrinsically fluorescent metabolic cofactors NADH and NADPH with subcellular spatial resolution. However, the interpretation of NAD(P)H FLIM measurements in terms of the metabolic state of the sample are not completely understood. We have used this technique to explore changes in metabolism associated with hearing onset and with acquired (age-related and noise-induced) hearing loss. We show that these conditions are associated with altered NAD(P)H fluorescence lifetimes, use a simple cell model to confirm an inverse relationship between τbound and oxidative stress, and propose such changes as a potential index of oxidative stress applicable to all mammalian cell types.

scholarly journals Endoplasmic reticulum stress induces a novel Ca2+ signalling system initiated by Ca2+ microdomains

2020 ◽  
Author(s):  
Constanza Feliziani ◽  
Gonzalo Quasollo ◽  
Deborah Holstein ◽  
Macarena Fernandez ◽  
James C Paton ◽  
...  
Keyword(s):  
Endoplasmic Reticulum ◽  
Er Stress ◽  
Cell Model ◽  
Signal Transduction Pathway ◽  
Unfolded Proteins ◽  
Potent Inducer ◽  
Human Astrocytes ◽  
Receptor Isoforms ◽  
A Cell ◽  
Er Homeostasis

AbstractThe accumulation of unfolded proteins within the Endoplasmic Reticulum (ER) activates a signal transduction pathway termed the unfolded protein response (UPR), which attempts to restore ER homeostasis. If homeostasis cannot be restored, UPR signalling ultimately induces apoptosis. Ca2+ depletion in the ER is a potent inducer of ER stress. Despite the ubiquity of Ca2+ as intracellular messenger, the precise mechanism (s) by which Ca2+ release affects the UPR remains unknown. Use of a genetically encoded Ca2+ indicator (GCamP6) that is tethered to the ER membrane, uncovered novel Ca2+ signalling events initiated by Ca2+ microdomains in human astrocytes under ER stress, as well as in a cell model deficient in all three IP3 Receptor isoforms. Pharmacological and molecular studies indicate that these local events are mediated by translocons. Together, these data reveal the existence of a previously unrecognized mechanism by which stressor-mediated Ca2+ release regulates ER stress.

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