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p27 kip1 Modulates the Morphology and Phagocytic Activity of Microglia. Int J Mol Sci 2022; 23:ijms231810432. [PMID: 36142366 PMCID: PMC9499407 DOI: 10.3390/ijms231810432] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/18/2022] [Revised: 09/02/2022] [Accepted: 09/05/2022] [Indexed: 11/24/2022] Open
Abstract
p27kip1 is a multifunctional protein that promotes cell cycle exit by blocking the activity of cyclin/cyclin-dependent kinase complexes as well as migration and motility via signaling pathways that converge on the actin and microtubule cytoskeleton. Despite the broad characterization of p27kip1 function in neural cells, little is known about its relevance in microglia. Here, we studied the role of p27kip1 in microglia using a combination of in vitro and in situ approaches. While the loss of p27kip1 did not affect microglial density in the cerebral cortex, it altered their morphological complexity in situ. However, despite the presence of p27kip1 in microglial processes, as shown by immunofluorescence in cultured cells, loss of p27kip1 did not change microglial process motility and extension after applying laser-induced brain damage in cortical brain slices. Primary microglia lacking p27kip1 showed increased phagocytic uptake of synaptosomes, while a cell cycle dead variant negatively affected phagocytosis. These findings indicate that p27kip1 plays specific roles in microglia.
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Abstract
Alpha-synuclein (α-SYN) is the main component of anomalous protein aggregates (Lewy bodies) that play a crucial role in several neurodegenerative diseases (synucleinopathies) like Parkinson’s disease and multiple system atrophy. However, the mechanisms involved in its transcriptional regulation are poorly understood. We investigated here the role of the cyclin-dependent kinase (Cdk) inhibitor and transcriptional regulator p27Kip1 (p27) in the regulation of α-SYN expression. We observed that selective deletion of p27 by CRISPR/Cas9 technology in neural cells resulted in increased levels of α-SYN. Knock-down of the member of the same family p21Cip1 (p21) also led to increased α-SYN levels, indicating that p27 and p21 collaborate in the repression of α-SYN transcription. We demonstrated that this repression is mediated by the transcription factor E2F4 and the member of the retinoblastoma protein family p130 and that it is dependent of Cdk activity. Chromatin immunoprecipitation analysis revealed specific binding sites for p27, p21 and E2F4 in the proximal α-SYN gene promoter. Finally, luciferase assays revealed a direct action of p27, p21 and E2F4 in α-SYN gene expression. Our findings reveal for the first time a negative regulatory mechanism of α-SYN expression, suggesting a putative role for cell cycle regulators in the etiology of synucleinopathies.
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A dangerous liaison: Leptin and sPLA2-IIA join forces to induce proliferation and migration of astrocytoma cells. PLoS One 2017; 12:e0170675. [PMID: 28249041 PMCID: PMC5331986 DOI: 10.1371/journal.pone.0170675] [Citation(s) in RCA: 9] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/22/2016] [Accepted: 01/09/2017] [Indexed: 11/19/2022] Open
Abstract
Glioblastoma, the most aggressive type of primary brain tumour, shows worse prognosis linked to diabetes or obesity persistence. These pathologies are chronic inflammatory conditions characterized by altered profiles of inflammatory mediators, including leptin and secreted phospholipase A2-IIA (sPLA2-IIA). Both proteins, in turn, display diverse pro-cancer properties in different cell types, including astrocytes. Herein, to understand the underlying relationship between obesity and brain tumors, we investigated the effect of leptin, alone or in combination with sPLA2-IIA on astrocytoma cell functions. sPLA2-IIA induced up-regulation of leptin receptors in 1321N1 human astrocytoma cells. Leptin, as well as sPLA2-IIA, increased growth and migration in these cells, through activation/phosphorylation of key proteins of survival cascades. Leptin, at concentrations with minimal or no activating effects on astrocytoma cells, enhanced growth and migration promoted by low doses of sPLA2-IIA. sPLA2-IIA alone induced a transient phosphorylation pattern in the Src/ERK/Akt/mTOR/p70S6K/rS6 pathway through EGFR transactivation, and co-addition of leptin resulted in a sustained phosphorylation of these signaling regulators. Mechanistically, EGFR transactivation and tyrosine- and serine/threonine-protein phosphatases revealed a key role in this leptin-sPLA2-IIA cross-talk. This cooperative partnership between both proteins was also found in primary astrocytes. These findings thus indicate that the adipokine leptin, by increasing the susceptibility of cells to inflammatory mediators, could contribute to worsen the prognosis of tumoral and neurodegenerative processes, being a potential mediator of some obesity-related medical complications.
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Kaneko YS, Ota A, Nakashima A, Nagasaki H, Kodani Y, Mori K, Nagatsu T. Lipopolysaccharide treatment arrests the cell cycle of BV-2 microglial cells in G₁ phase and protects them from UV light-induced apoptosis. J Neural Transm (Vienna) 2014; 122:187-99. [PMID: 24919883 DOI: 10.1007/s00702-014-1256-5] [Citation(s) in RCA: 4] [Impact Index Per Article: 0.4] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/28/2014] [Accepted: 06/04/2014] [Indexed: 01/03/2023]
Abstract
We previously reported that an optimal dose of lipopolysaccharide (LPS) markedly extends the lifespan of murine primary-cultured microglia by suppressing cell death pathways. In this study, we investigated the effects of LPS pretreatment on UV light-induced apoptosis of cells from the microglial cell line BV-2. More than half of BV-2 cells were apoptotic, and procaspase-3 was cleaved into its active form at 3 h of UV irradiation. In contrast, in BV-2 cells treated with LPS for 24 h, UV irradiation caused neither apoptosis nor procaspase-3 cleavage. LPS treatment arrested the cell cycle in G1 phase and upregulated cyclin-dependent kinase inhibitor p21(Waf1/Cip1) and growth arrest and DNA damage-inducible (GADD) 45α in BV-2 cells. When p21(Waf1/Cip1) and GADD45α were knocked down by small interfering RNA, procaspase-3 was cleaved into its active form to induce apoptosis. Our findings suggest that LPS inhibits UV-induced apoptosis in BV-2 cells through arrest of the cell cycle in G1 phase by upregulation of p21(Waf1/Cip1) and GADD45α. Excessive activation of microglia may play a critical role in the exacerbation of neurodegeneration, therefore, normalizing the precise regulation of apoptosis may be a new strategy to prevent the deterioration caused by neurodegenerative disorders.
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Affiliation(s)
- Yoko S Kaneko
- Department of Physiology, Fujita Health University School of Medicine, 1-98 Dengakugakubo, Kutsukake-cho, Toyoake, 470-1192, Japan,
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Pace E, Ferraro M, Siena L, Scafidi V, Gerbino S, Di Vincenzo S, Gallina S, Lanata L, Gjomarkaj M. Carbocysteine regulates innate immune responses and senescence processes in cigarette smoke stimulated bronchial epithelial cells. Toxicol Lett 2013; 223:198-204. [PMID: 24076166 DOI: 10.1016/j.toxlet.2013.09.013] [Citation(s) in RCA: 23] [Impact Index Per Article: 2.1] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/11/2013] [Revised: 09/15/2013] [Accepted: 09/17/2013] [Indexed: 02/07/2023]
Abstract
Cigarette smoke represents the major risk factor for chronic obstructive pulmonary disease (COPD). Cigarette smoke extracts (CSE) alter TLR4 expression and activation in bronchial epithelial cells. Carbocysteine, an anti-oxidant and mucolytic agent, is effective in reducing the severity and the rate of exacerbations in COPD patients. The effects of carbocysteine on TLR4 expression and on the TLR4 activation downstream events are largely unknown. This study was aimed to explore whether carbocysteine, in a human bronchial epithelial cell line (16-HBE), counteracted some pro-inflammatory CSE-mediated effects. In particular, TLR4 expression, LPS binding, p21 (a senescence marker), IL-8 mRNA and release in CSE-stimulated 16-HBE as well as actin reorganization in neutrophils cultured with supernatants from bronchial epithelial cells which were stimulated with CSE and/or carbocysteine were assessed. TLR4 expression, LPS binding, and p21 expression were assessed by flow cytometry, IL-8 mRNA by Real Time PCR and IL-8 release by ELISA. Actin reorganization, a prerequisite for cell migration, was determined using Atto 488 phalloidin in neutrophils by flow cytometry and fluorescence microscopy. CSE increased: (1) TLR4, LPS binding and p21 expression; (2) IL-8 mRNA and IL-8 release due to IL-1 stimulation; (3) neutrophil migration. Carbocysteine in CSE stimulated bronchial epithelial cells, reduced: (1) TLR4, LPS binding and p21; (2) IL-8 mRNA and IL-8 release due to IL-1 stimulation; (3) neutrophil chemotactic migration. In conclusion, the present study provides compelling evidences that carbocysteine may contribute to control the inflammatory and senescence processes present in smokers.
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Affiliation(s)
- Elisabetta Pace
- Institute of Biomedicine and Molecular Immunology, National Research Council, Via Ugo La Malfa, 153, 90146 Palermo, Italy.
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Bell-Temin H, Zhang P, Chaput D, King MA, You M, Liu B, Stevens SM. Quantitative Proteomic Characterization of Ethanol-Responsive Pathways in Rat Microglial Cells. J Proteome Res 2013; 12:2067-77. [DOI: 10.1021/pr301038f] [Citation(s) in RCA: 28] [Impact Index Per Article: 2.5] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/30/2022]
Affiliation(s)
- Harris Bell-Temin
- Department
of Cell Biology,
Microbiology, and Molecular Biology, University of South Florida, 4202 East Fowler Avenue, Tampa, Florida 33620,
United States
| | | | - Dale Chaput
- Department
of Cell Biology,
Microbiology, and Molecular Biology, University of South Florida, 4202 East Fowler Avenue, Tampa, Florida 33620,
United States
| | - Michael A. King
- Department of Veterans Affairs Medical Center, 1601 SW Archer Road, Gainesville,
Florida 32608, United States
| | - Min You
- Department of Molecular Pharmacology
and Physiology, University of South Florida, 12901 Bruce B. Downs Boulevard, Tampa, Florida 33612, United States
| | | | - Stanley M. Stevens
- Department
of Cell Biology,
Microbiology, and Molecular Biology, University of South Florida, 4202 East Fowler Avenue, Tampa, Florida 33620,
United States
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Abstract
An important component of chronic neurodegenerative diseases is the generation of an innate inflammatory response within the CNS. Microglial and astroglial cells play a key role in the development and maintenance of this inflammatory response, showing enhanced proliferation and activation. We studied the time course and regulation of microglial proliferation, using a mouse model of prion disease. Our results show that the proliferation of resident microglial cells accounts for the expansion of the population during the development of the disease. We identify the pathway regulated by the activation of CSF1R and the transcription factors PU.1 and C/EBPα as the molecular regulators of the proliferative response, correlating with the chronic human neurodegenerative conditions variant Creutzfeldt-Jakob disease and Alzheimer's disease. We show that targeting the activity of CSF1R inhibits microglial proliferation and slows neuronal damage and disease progression. Our results demonstrate that microglial proliferation is a major component in the evolution of chronic neurodegeneration, with direct implications for understanding the contribution of the CNS innate immune response to disease progression.
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Bone marrow stromal cells induce cell cycle arrest in reactive astrocytes in vitro. Neurosci Lett 2012; 522:62-6. [PMID: 22705907 DOI: 10.1016/j.neulet.2012.06.017] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.1] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/17/2012] [Revised: 06/04/2012] [Accepted: 06/05/2012] [Indexed: 12/29/2022]
Abstract
Transplantation of bone marrow stromal cells (BMSCs) reduces astrogliosis, decreases scar thickness and improves neurological functional recovery after brain damage. It is believed that transplanted BMSCs have a profound influence on astrocytes. To obtain the possible mechanism in their interaction, a co-culture system between BMSCs and astrocytes were set to investigate whether BMSCs could modulate cell cycle machinery in reactive astrocytes. The results obtained showed cell cycle regulatory proteins, cdk4 along with its activator cyclin D1, and PCNA increased while p27, an endogenous cyclin-dependent kinase inhibitor, deceased in glutamate-treated astrocytes in vitro. However, BMSCs influenced cell cycle elements in the cocultured astrocytes: cyclin D1, cdk 4 and PCNA were downregulated, while p27 was unregulated. Flow cytometry showed astrocytes in the S phase after glutamate incubation increased to 17.4±2.0% while restored to a level of 7.8±1.1% when cocultured with BMSCs. l-Canavanine, an inhibitor of inducible nitric oxide synthase, partially reversed the S phase to 11.3±0.4% in the cocultured astrocytes. These data indicated that BMSCs might inhibit the cell cycle control system in reactive astrocytes and nitric oxide signaling was involved in this process. The decline of astrogliosis conferred by BMSCs may derive from their effect of inhibiting the cell cycle progression in astrocytes.
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Abstract
Astrogliosis is induced by neuronal damage and is also a pathological feature of the major aging-related neurodegenerative disorders. The mechanisms that control the cascade of astrogliosis have not been well established. In a previous study, we identified a novel androgen receptor (AR)-interacting protein, p44/WDR77, that plays a critical role in the proliferation and differentiation of prostate epithelial cells. In the present study, we found that deletion of the p44/WDR77 gene caused premature death with dramatic astrogliosis in mouse brain. We further found that p44/WDR77 is expressed in astrocytes and that loss of p44/WDR77 expression in astrocytes leads to growth arrest and astrogliosis. The astrocyte activation induced by deletion of the p44/WDR77 gene was associated with upregulation of p21(Cip1) expression and NF-κB activation. Silencing p21(Cip1) or NF-κB p65 expression with short hairpin RNA (shRNA) abolished astrocyte activation and rescued the astrocyte growth inhibition induced by deletion of the p44/WDR77 gene. Our results reveal a novel role for p44/WDR77 in the control of astrocyte activation through p21(Cip1) and NF-κB signaling.
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Yu HM, Zhao YM, Luo XG, Feng Y, Ren Y, Shang H, He ZY, Luo XM, Chen SD, Wang XY. Repeated lipopolysaccharide stimulation induces cellular senescence in BV2 cells. Neuroimmunomodulation 2012; 19:131-6. [PMID: 22248729 DOI: 10.1159/000330254] [Citation(s) in RCA: 57] [Impact Index Per Article: 4.8] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 01/19/2011] [Accepted: 06/17/2011] [Indexed: 11/19/2022] Open
Abstract
BACKGROUND AND AIM The dual action of microglia in neurodegenerating diseases has been controversial for some time. Recent studies indicate that microglia senescence might be the key determinant. When microglia age, they function abnormally and fail to respond correctly to stimuli, which eventually promotes neurodegeneration. Accumulating evidence has shown a close relationship between inflammation and aging. Since neuroinflammation is characterized by microglia activation, we assessed if the repeated activation of microglia would lead to senescence. METHOD The microglia cell line BV2 was repeatedly stimulated every 48 h with lipopolysaccharide (LPS; 10 ng/ml) and senescence was evaluated by β-galactosidase staining and the presence of senescence-associated heterochromatic foci as well as by cell cycle arrest detection by flow cytometry. The senescence-associated protein p53 was also detected by Western blot. RESULTS β-galactosidase staining was barely detectable in control cells, while it tended to increase with repeated LPS stimulation and was positive in most cells after stimulation with LPS 6 times. Similarly, senescence-associated heterochromatic foci were most prominent in cells repeatedly stimulated with LPS, while almost undetectable in control cells or cells receiving a single stimulation. p53 expression was highest in the cells that received LPS stimulation 6 times, and the largest number of cells arrested in the G0/G1 phase was observed in this same group. CONCLUSION Microglial cells tend to undergo senescence after repeated activation, implying that microglia senescence may start after multiple inflammatory challenges.
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Affiliation(s)
- Hong-Mei Yu
- Department of Laboratory Medicine, First Affiliated Hospital of China Medical University, Shenyang, China
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Través PG, López-Fontal R, Luque A, Hortelano S. The Tumor Suppressor ARF Regulates Innate Immune Responses in Mice. THE JOURNAL OF IMMUNOLOGY 2011; 187:6527-38. [DOI: 10.4049/jimmunol.1004070] [Citation(s) in RCA: 23] [Impact Index Per Article: 1.8] [Reference Citation Analysis] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 12/28/2022]
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Labuzek K, Liber S, Gabryel B, Bułdak L, Okopień B. Ambivalent effects of compound C (dorsomorphin) on inflammatory response in LPS-stimulated rat primary microglial cultures. Naunyn Schmiedebergs Arch Pharmacol 2009; 381:41-57. [PMID: 19940979 DOI: 10.1007/s00210-009-0472-2] [Citation(s) in RCA: 15] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/08/2009] [Accepted: 11/03/2009] [Indexed: 12/13/2022]
Abstract
It was proven that compound C displays beneficial effects in models of inflammatory-induced anemia, ischemic stroke, and fibrodysplasia ossificans progressiva. Compound C influence on microglia, playing a major role in neuroinflammation, has not been evaluated yet. The aim of the present study was to determine the effect of compound C on cytokine release, NO, and reactive oxygen species (ROS) production. The rat microglial cultures were obtained by shaking the primary mixed glial cultures. Cytokine and nitrite concentrations were assayed using ELISA kits. ROS were assayed with nitroblue tetrazolium chloride. AMPK activity was assayed using the SAMS peptide. The expression of arginase I, NF-kappaB p65, and hypoxia-inducible factor-1 alpha (HIF-1 alpha) was evaluated using Western blot. Compound C displayed ambivalent effect depending on microglia basal activity. It up-regulated the release of TNF alpha and NO production and increased the expression of arginase I in non-stimulated microglia. However, compound C down-regulated IL-1 beta, IL-6 and TNF alpha release, NO, ROS production, and AMPK activity, diminished NF-kappaB and HIF-1 alpha expression, as well as increased arginase I expression in lipopolysaccharide (LPS)-stimulated microglia. Compound C did not affect iNOS expression and IL-10 and TGF-beta release in non-stimulated and LPS-stimulated microglia. The observed alterations in the release or production of inflammatory mediators may be explained by the changes in NF-kappaB, HIF-1 alpha, and arginase I expression and 3-(4,5-dimethylthazol-2-yl)-2,5-diphenyltetrazolinum bromide values in response to LPS, whereas the basis for the compound C effect on non-stimulated microglia remains to be investigated.
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Affiliation(s)
- Krzysztof Labuzek
- Department of Clinical Pharmacology, Medical University of Silesia, Medyków 18, PL 40-752, Katowice, Poland.
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