Autophagy induced by silica nanoparticles protects RAW264.7 macrophages from cell death

Marquardt, Clarissa; Fritsch‐Decker, Susanne; Al‐Rawi, Marco; Diabaté, Silvia; Weiss, Carsten

doi:10.1016/j.tox.2017.01.019

Cited by 58 publications

(43 citation statements)

References 54 publications

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“…A more detailed analysis concerning the mode of cell death showed that SiO 2 NPs trigger condensation of DNA and membrane rupture reminiscent of late apoptotic events (Figure B and Figure S6, Supporting Information). Moreover, in the bright‐field images vacuoles are visible that are indicative of autophagy, an adaptive process initiated to improve survival . In contrast to our freshly synthesized material (APTES‐11 and APTES‐23), commercial amine‐modified SiO 2 NPs (SiO 2 ‐NH 2 (C)) were nontoxic but still provoked formation of vacuoles (Figure and Figure S6, Supporting Information).…”

Section: Resultsmentioning

confidence: 84%

“…Moreover, in the bright-field images vacuoles are visible that are indicative of autophagy, an adaptive process initiated to improve survival. [32] In contrast to our freshly synthesized material (APTES-11 and APTES-23), commercial amine-modified SiO 2 NPs (SiO 2 -NH 2 (C)) were nontoxic but still provoked formation of vacuoles ( Figure 2 and Figure S6, Supporting Information). For comparison, positively charged PS-NH 2 NPs (Table 1) already drastically induced cell death at lower concentrations, categorized as late apoptosis in line with previous reports.…”

Section: Biocompatibility Of Sio 2 Npsmentioning

confidence: 70%

Section: Methodsmentioning

confidence: 99%

“…Data are depicted as means ± SEM, which are derived from quadruplicate exposures and two independent experiments (n = 8). For more details see also Marquardt et al (2017) and Donauer et al (2012). [32,42] Real-Time Imaging: In order to analyze RAW264.7 macrophages by real-time imaging at single cell level, cells were first seeded in 96-well plates and incubated overnight as described above.…”

Section: Methodsmentioning

confidence: 99%

“…For more details see also Marquardt et al (2017) and Donauer et al (2012). [32,42] Real-Time Imaging: In order to analyze RAW264.7 macrophages by real-time imaging at single cell level, cells were first seeded in 96-well plates and incubated overnight as described above. Next day, macrophages were directly incubated with 0.1 µg mL −1 Hoechst 33342, 0.083 µg mL −1 propidium iodide (PI) and 500 × 10 −9 m Lysotracker, respectively, for 1 h at 37 °C and 5% CO 2 .…”

Section: Methodsmentioning

confidence: 99%

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Biocompatibility of Amine‐Functionalized Silica Nanoparticles: The Role of Surface Coverage

Hsiao

Fritsch‐Decker

Leidner

et al. 2019

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Here, amorphous silica nanoparticles (NPs), one of the most abundant nanomaterials, are used as an example to illustrate the utmost importance of surface coverage by functional groups which critically determines biocompatibility. Silica NPs are functionalized with increasing amounts of amino groups, and the number of surface exposed groups is quantified and characterized by detailed NMR and fluorescamine binding studies. Subsequent biocompatibility studies in the absence of serum demonstrate that, irrespective of surface modification, both plain and amine‐modified silica NPs trigger cell death in RAW 264.7 macrophages. The in vitro results can be confirmed in vivo and are predictive for the inflammatory potential in murine lungs. In the presence of serum proteins, on the other hand, a replacement of only 10% of surface‐active silanol groups by amines is sufficient to suppress cytotoxicity, emphasizing the relevance of exposure conditions. Mechanistic investigations identify a key role of lysosomal injury for cytotoxicity only in the presence, but not in the absence, of serum proteins. In conclusion, this work shows the critical need to rigorously characterize the surface coverage of NPs by their constituent functional groups, as well as the impact of serum, to reliably establish quantitative nanostructure activity relationships and develop safe nanomaterials.

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Section: Resultsmentioning

confidence: 84%

Section: Biocompatibility Of Sio 2 Npsmentioning

confidence: 70%

Section: Methodsmentioning

confidence: 99%

Section: Methodsmentioning

confidence: 99%

Section: Methodsmentioning

confidence: 99%

See 3 more Smart Citations

Biocompatibility of Amine‐Functionalized Silica Nanoparticles: The Role of Surface Coverage

Hsiao

Fritsch‐Decker

Leidner

et al. 2019

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A Quantitative Method for Determining Uptake of Silica Nanoparticles in Macrophages by Single Particle Inductively Coupled Plasma–Mass Spectrometry

2022

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Engineered nanomaterials are becoming increasingly ubiquitous in our society, with numerous applications in medicine, consumer products, bioremediation, and advanced materials. As these nanomaterials increase in variety, analyzing their characteristics is of great importance. Single particle inductively coupled plasma–mass spectrometry (SP‐ICP‐MS) is a high‐throughput, sensitive, and robust instrumental analysis method used to simultaneously characterize and quantify nanoparticles in a variety of matrices. One such type of nanoparticle of interest is amorphous silica nanoparticles (SiNPs). SiNPs have widespread use in consumer products such as food and cosmetics and are prime candidates for novel medical applications and uses in environmental bioremediation. Despite their increased use, SiNPs have been shown to have toxicological properties in vitro and in vivo, particularly with regard to the immune system. Because of the potential for increased SiNP exposure in the general public and in occupational settings, examining the relationship that SiNPs have with immune cells such as macrophages to elucidate mechanisms of toxicity is vital. To effectively determine the toxicity of nanoparticles, it is critical to examine dosimetry and the amount of nanoparticles taken up by the cell of interest. Different cell types have different uptake profiles, and varying physicochemical properties govern nanoparticle dosimetry and uptake in cells. Here, we describe a protocol using SP‐ICP‐MS to quantify and characterize the size, size distribution, and amount of SiNPs present in a cell and medium sample. We use a single‐step digestion, which allows for the digestion of biological matrices while simultaneously keeping the SiNPs intact for SP‐ICP‐MS analysis. Clinically, this approach has the potential to be used as a method for analyzing SiNPs in other biological matrices, potentially as a way of defining SiNP uptake as a biomarker in immune‐mediated diseases. © 2022 Wiley Periodicals LLC. Basic Protocol 1: Treatment of cells with silica nanoparticles (SiNPs) and digestion of biological matrices Support Protocol 1: Culturing RAW 264.7 cells for SiNP uptake assay Support Protocol 2: Determination of SiNP size via dynamic light scattering Support Protocol 3: Optimization of sample and ICP‐MS parameters for SP‐ICP‐MS analysis of cells and medium Basic Protocol 2: Analysis and quantification of SiNP uptake in macrophages with SP‐ICP‐MS

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Melatonin enhances autophagy and decreases apoptosis induced by nanosilica in RAW264.7 cells

Zhang

et al. 2019

IUBMB Life

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Melatonin is one of the main hormones that regulate biological rhythms and have immunomodulation, anti‐inflammatory, and antioxidation functions. In this study, we aimed to explore the effect of melatonin on the autophagy, apoptosis, and inflammatory reaction of macrophages (RAW264.7 cells) stimulated by nanosilica. SiO2 (100 mg/mL, 10–20 nm) was used to stimulate RAW264.7 cells at different time points (0, 2, 4, 8, 12, and 24 hr). Melatonin (200 μM) was added to SiO2‐stimulated macrophages at 12 hr. Beclin‐1, LC3, Bax, Bcl‐2, and Caspase‐3 were examined with western blotting. Flow cytometry was used to detect apoptosis. The levels of TNF‐α, IL‐1β, and IL‐18 were detected by ELISA. The level of TNF‐α in the supernatant of SiO2‐stimulated cells gradually increased with time but decreased following melatonin administration. In contrast, the expression of IL‐1β and IL‐18 increased after melatonin treatment. LC3 and Bax signaling pathways were activated in SiO2‐stimulated RAW264.7 cells, showing elevated expression of LC3 and reduced expression of Bax in the melatonin‐treated cells. GFP‐LC3 puncta were significantly increased in SiO2‐stimulated RAW264.7 cells and decreased in melatonin‐treated cells. The apoptotic rate in SiO2‐stimulated RAW264.7 cells increased with time and decreased after melatonin treatment, and the number of phagosomes increased with the stimulation of nanosilica and the treatment of melatonin. Melatonin might promote autophagy and inhibit apoptosis as well as inflammatory responses of RAW264.7 cells stimulated by nanosilica. © 2019 IUBMB Life, 2019

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Autophagy induced by silica nanoparticles protects RAW264.7 macrophages from cell death

Cited by 58 publications

References 54 publications

Biocompatibility of Amine‐Functionalized Silica Nanoparticles: The Role of Surface Coverage

Biocompatibility of Amine‐Functionalized Silica Nanoparticles: The Role of Surface Coverage

A Quantitative Method for Determining Uptake of Silica Nanoparticles in Macrophages by Single Particle Inductively Coupled Plasma–Mass Spectrometry

Melatonin enhances autophagy and decreases apoptosis induced by nanosilica in RAW264.7 cells

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