Amphiphysin 1 Is Important for Actin Polymerization during Phagocytosis

Amphiphysin 1 is involved in clathrin-mediated endocytosis. In this study, we demonstrate that amphiphysin 1 is essential for cellular phagocytosis and that it is critical for actin polymerization. Phagocytosis in Sertoli cells was induced by stimulating phosphatidylserine receptors. This stimulation led to the formation of actin-rich structures, including ruffles, phagocytic cups, and phagosomes, all of which showed an accumulation of amphiphysin 1. Knocking out amphiphysin 1 by RNA interference in the cells resulted in the reduction of ruffle formation, actin polymerization, and phagocytosis. Phagocytosis was also drastically decreased in amph 1 (−/−) Sertoli cells. In addition, phosphatidylinositol-4,5-bisphosphate–induced actin polymerization was decreased in the knockout testis cytosol. The addition of recombinant amphiphysin 1 to the cytosol restored the polymerization process. Ruffle formation in small interfering RNA-treated cells was recovered by the expression of constitutively active Rac1, suggesting that amphiphysin 1 functions upstream of the protein. These findings support that amphiphysin 1 is important in the regulation of actin dynamics and that it is required for phagocytosis.

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Faculty Opinions recommendation of DICER-LIKE 4 is required for RNA interference and produces the 21-nucleotide small interfering RNA component of the plant cell-to-cell silencing signal.

Faculty Opinions – Post-Publication Peer Review of the Biomedical Literature ◽

10.3410/f.1029052.345437 ◽

2005 ◽

Author(s):

Andy Maule

Keyword(s):

Rna Interference ◽

Plant Cell ◽

Small Interfering Rna ◽

Interfering Rna

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DrosophilaoncogeneGas41is an RNA interference modulator that intersects heterochromatin and the small interfering RNA pathway

FEBS Journal ◽

10.1111/febs.13115 ◽

2014 ◽

Vol 282 (1) ◽

pp. 153-173 ◽

Cited By ~ 4

Author(s):

Sumit G. Gandhi ◽

Indira Bag ◽

Saswati Sengupta ◽

Manika Pal-Bhadra ◽

Utpal Bhadra

Keyword(s):

Rna Interference ◽

Small Interfering Rna ◽

Interfering Rna

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RNA Interference of Human Papillomavirus Type 18 E6 and E7 Induces Senescence in HeLa Cells

Journal of Virology ◽

10.1128/jvi.77.10.6066-6069.2003 ◽

2003 ◽

Vol 77 (10) ◽

pp. 6066-6069 ◽

Cited By ~ 137

Author(s):

Allison H. S. Hall ◽

Kenneth A. Alexander

Keyword(s):

Cell Proliferation ◽

Human Papillomavirus ◽

Rna Interference ◽

Hela Cells ◽

Tumor Suppressors ◽

Small Interfering Rna ◽

Promote Cell Proliferation ◽

E6 And E7 ◽

Cellular Dna ◽

Interfering Rna

ABSTRACT The human papillomavirus oncoproteins E6 and E7 promote cell proliferation and contribute to carcinogenesis by interfering with the activities of cellular tumor suppressors. We used a small interfering RNA molecule targeting the E7 region of the bicistronic E6 and E7 mRNA to induce RNA interference, thereby reducing expression of E6 and E7 in HeLa cells. RNA interference of E6 and E7 also inhibited cellular DNA synthesis and induced morphological and biochemical changes characteristic of cellular senescence. These results demonstrate that reducing E6 and E7 expression is sufficient to cause HeLa cells to become senescent.

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Structurally modulated codelivery of siRNA and Argonaute 2 for enhanced RNA interference

Proceedings of the National Academy of Sciences ◽

10.1073/pnas.1719565115 ◽

2018 ◽

Vol 115 (12) ◽

pp. E2696-E2705 ◽

Cited By ~ 20

Author(s):

Jiahe Li ◽

Connie Wu ◽

Wade Wang ◽

Yanpu He ◽

Elad Elkayam ◽

...

Keyword(s):

Molecular Structure ◽

Rna Interference ◽

Small Interfering Rna ◽

Sirna Delivery ◽

Effector Protein ◽

Side Group ◽

Argonaute 2 ◽

Fundamental Research ◽

Delivery Vehicles ◽

Interfering Rna

Small interfering RNA (siRNA) represents a promising class of inhibitors in both fundamental research and the clinic. Numerous delivery vehicles have been developed to facilitate siRNA delivery. Nevertheless, achieving highly potent RNA interference (RNAi) toward clinical translation requires efficient formation of RNA-induced gene-silencing complex (RISC) in the cytoplasm. Here we coencapsulate siRNA and the central RNAi effector protein Argonaute 2 (Ago2) via different delivery carriers as a platform to augment RNAi. The physical clustering between siRNA and Ago2 is found to be indispensable for enhanced RNAi. Moreover, by utilizing polyamines bearing the same backbone but distinct cationic side-group arrangements of ethylene diamine repeats as the delivery vehicles, we find that the molecular structure of these polyamines modulates the degree of siRNA/Ago2-mediated improvement of RNAi. We apply this strategy to silence the oncogene STAT3 and significantly prolong survival in mice challenged with melanoma. Our findings suggest a paradigm for RNAi via the synergistic coassembly of RNA with helper proteins.

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Folate Receptor-Mediated Small Interfering RNA Delivery: Recent Developments and Future Directions for RNA Interference Therapeutics

Nucleic Acid Therapeutics ◽

10.1089/nat.2020.0882 ◽

2021 ◽

Author(s):

Sumit Gangopadhyay ◽

Rahul R. Nikam ◽

Kiran R. Gore

Keyword(s):

Rna Interference ◽

Small Interfering Rna ◽

Folate Receptor ◽

Future Directions ◽

Recent Developments ◽

Interfering Rna

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Formation of neutrophil extracellular traps requires actin cytoskeleton rearrangements

Blood ◽

10.1182/blood.2021013565 ◽

2022 ◽

Author(s):

Evelien G.G. Sprenkeler ◽

Anton T.J. Tool ◽

Stefanie Henriet ◽

Robin van Bruggen ◽

Taco W. Kuijpers

Keyword(s):

Actin Polymerization ◽

Nuclear Dna ◽

Myosin Ii ◽

Neutrophil Extracellular Traps ◽

Actin Dynamics ◽

Polymerization Process ◽

Effector Cells ◽

Extracellular Traps ◽

Cytoskeleton Rearrangements ◽

Cellular Components

Neutrophils are important effector cells in the host defense against invading micro-organisms. One of the mechanisms they employ to eliminate pathogens is the release of neutrophil extracellular traps (NETs). Although NET release and subsequent cell death known as NETosis have been intensively studied, the cellular components and factors determining or facilitating the formation of NETs remain incompletely understood. Using various actin polymerization and myosin II modulators on neutrophils from healthy individuals, we show that intact F-actin dynamics and myosin II function are essential for NET formation when induced by different stimuli, i.e. phorbol 12-myristate 13-acetate, monosodium urate crystals and Candida albicans. The role of actin polymerization in NET formation could not be explained by the lack of reactive oxygen species production or granule release, which were normal or enhanced under the given conditions. Neutrophils from patients with very rare inherited actin polymerization defects by either ARPC1B- or MKL1-deficiency also failed to show NETosis. We found that upon inhibition of actin dynamics there is a lack of translocation of NE to the nucleus, which may well explain the impaired NET formation. Collectively, our data illustrate the essential requirement of an intact and active actin polymerization process, as well as active myosin II to enable the release of nuclear DNA by neutrophils during NET formation.

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RNA-Based Immunity Terminates Viral Infection in Adult Drosophila in the Absence of Viral Suppression of RNA Interference: Characterization of Viral Small Interfering RNA Populations in Wild-Type and Mutant Flies

Journal of Virology ◽

10.1128/jvi.05518-11 ◽

2011 ◽

Vol 85 (24) ◽

pp. 13153-13163 ◽

Cited By ~ 48

Author(s):

Y.-H. Han ◽

Y.-J. Luo ◽

Q. Wu ◽

J. Jovel ◽

X.-H. Wang ◽

...

Keyword(s):

Rna Interference ◽

Viral Infection ◽

Small Interfering Rna ◽

Viral Suppression ◽

Wild Type ◽

Interfering Rna ◽

Adult Drosophila

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Antiviral Effects of Small Interfering RNA Simultaneously Inducing RNA Interference and Type 1 Interferon in Coxsackievirus Myocarditis

Antimicrobial Agents and Chemotherapy ◽

10.1128/aac.06050-12 ◽

2012 ◽

Vol 56 (7) ◽

pp. 3516-3523 ◽

Cited By ~ 5

Author(s):

Jeonghyun Ahn ◽

Ara Ko ◽

Eun Jung Jun ◽

Minah Won ◽

Yoo Kyum Kim ◽

...

Keyword(s):

Rna Interference ◽

Small Interfering Rna ◽

Antiviral Treatment ◽

Coxsackievirus B3 ◽

Hydroxyl Group ◽

Specific Gene ◽

Type I ◽

Antiviral Effects ◽

Direct Demonstration ◽

Interfering Rna

ABSTRACTAntiviral therapeutics are currently unavailable for treatment of coxsackievirus B3, which can cause life-threatening myocarditis. A modified small interfering RNA (siRNA) containing 5′-triphosphate, 3p-siRNA, was shown to induce RNA interference and interferon activation. We aimed to develop a potent antiviral treatment using CVB3-specific 3p-siRNA and to understand its underlying mechanisms. Virus-specific 3p-siRNA was superior to both conventional virus-specific siRNA with an empty hydroxyl group at the 5′ end (OH-siRNA) and nonspecific 3p-siRNA in decreasing viral replication and subsequent cytotoxicity. A single administration of 3p-siRNA dramatically attenuated virus-associated pathological symptoms in mice with no signs of toxicity, and their body weights eventually reached the normal range. Myocardial inflammation and fibrosis were rare, and virus production was greatly reduced. A nonspecific 3p-siRNA showed relatively less protective effect under identical conditions, and a virus-specific OH-siRNA showed no protective effects. We confirmed that virus-specific 3p-siRNA simultaneously activated target-specific gene silencing and type I interferon signaling. We provide a clear proof of concept that coxsackievirus B3-specific 3p-siRNA has 2 distinct modes of action, which significantly enhance antiviral activities with minimal organ damage. This is the first direct demonstration of improved antiviral effects with an immunostimulatory virus-specific siRNA in coxsackievirus myocarditis, and this method could be applied to many virus-related diseases.

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