Titanium dioxide nanoparticles enhance macrophage activation by LPS through a TLR4-dependent intracellular pathway

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UNIVERSITA DEGLI STUDI DI PARMA Titanium dioxide nanoparticles enhance macrophage activation by LPS through a TLR4-dependent

Costa c, Magda Blosi c, Davide Gardini c, Camilla Del Pivo c, Adriele Prina-Mello d, Luisana Di Cristo a, Ovidio Bussolati b, Enrico

Department of Biomedical, Biotechnological and Translational Sciences, University of Parma; c Institute of Science and Technology for

1 UNIVERSITA DEGLI STUDI DI PARMA Titanium dioxide nanoparticles enhance macrophage activation by LPS through a TLR4-dependent intracellular pathway Massimiliano G. Bianchi a, Manfredi Allegri b, Anna L. Costa c, Magda Blosi c, Davide Gardini c, Camilla Del Pivo c, Adriele Prina-Mello d, Luisana Di Cristo a, Ovidio Bussolati b, Enrico Bergamaschi a a Unit of Occupational Medicine, Department of Clinical and Experimental Medicine and b Unit of General Pathology, Department of Biomedical, Biotechnological and Translational Sciences, University of Parma; c Institute of Science and Technology for Ceramics (CNR-ISTEC), National Research Council of Italy, Faenza(RA); d Centre for Research on Adaptive Nanostructures and Nanodevices (CRANN) and School of Medicine, Trinity College Dublin, Dublin Grant NMP4-SL

Polysaccharide tail CD14 BACKGROUND Bacterial Lipopolysaccharide (LPS or endotoxin) A common environmental PAMP (macrophage activator) Component of the outer membrane of Gram bacteria Elicits strong

2 Polysaccharide tail CD14 BACKGROUND Bacterial Lipopolysaccharide (LPS or endotoxin) A common environmental PAMP (macrophage activator) Component of the outer membrane of Gram bacteria Elicits strong inflammatory response in competent cells LPS OUT Gram - TLR4 Activation of Toll-like Receptor 4 pathway in Macrophages IN ADAPTOR Endosomes Lipid A Pyrogenic moiety MKKs NFkB Nos2 Il6, TNF Lysosomes Pro-inflammatory gene transcription

3 BACKGROUND TiO 2 nanoparticles (NPs) at a glance.. One of the most common manufactured metal-based NPs worldwide 5,4 tons in 21; expected to increase to 21,5 in 215 Used in several industrial applications Electronics, solar cells, paints, textiles Food, cosmetics, toothpaste Antibacterial and anti-polluting coatings Delivery of bio-active molecules Intrinsic Physicochemical properties Bio-activities - Inflammation - Oxidative stress - Cancerogenicity Direct particle-cell interaction

surface coatings BACKGROUND TiO 2 nanoparticles and the paradigm of protein corona Environmental/Biological Matrix size Nanostructured material

4 surface coatings BACKGROUND TiO 2 nanoparticles and the paradigm of protein corona Environmental/Biological Matrix size Nanostructured material shape Biological behavior Adapted from Nel A.E. et al., Nat. Materials 29 surface chemistry A role for environmental contaminants in TiO 2 NP effects?

AIM To asses the effects of TiO 2 NP and LPS on murine macrophage Raw 264.7 Raw 264.

5 AIM To asses the effects of TiO 2 NP and LPS on murine macrophage Raw Raw Immuno-competent cells Express TLR4 receptors Biological parameters evaluated Cytotoxicity Cell end points Inflammatory markers - Cell viability - NO production - Pro-inflammatory genes - Cytokine secretion Experimental design LPS TiO 2 NPs TiO 2 NPs + LPS Cell monolayer

6 BACKGROUND Physico-chemical properties of NAMA41 and Aeroxide P25 TiO 2 NP XRD phase distribution Anatase (%) B=Brookite R=Rutile (%) Density (g/cm 3 ) SSA BET (m 2 /g) d BET (nm) NAMA , B Aeroxide P , R Mean size distribution by intensity and ζ potential for.125 mg ml 1 of NAMA41 and Aeroxide P25 dispersed in deionized water and complete culture medium Deionized water natural ph Deionized water medium ph Complete culture medium TiO 2 NP ph Size (d. nm) PdI ζ pot. (mv) ph Size (d. nm) PdI ζ pot. (mv) ph Size (d. nm) PdI ζ pot. (mv) NAMA41 3,9 45,48 41,2 7,3 9864,76-15,9 7,3 1962,98-1,9 DEV. ST 1,9, 239,3,4 147,3,5 Aeroxide P25 6,5 286,3 37,4 7,7 3425,36-11, 7,7 532,53-1,8 DEV. ST 4,4,9 226,1,1 16,11,4

7 Cell viability (% of control) RESULTS Cytotoxicity Effects of P25 and LPS on cell viability Control LPS 1 ng/ml LPS 1 ng/ml 12 1 * Resazurin assay P25 µg/cm Resazurin Not fluorescent Ex λ=536 nm Resorufin Em λ=59 nm *p <.5 vs. Untreated cultures P25 do not markedly affect cell viability up to 48h

8 Nos2/Actin protein (a.u.) RESULTS Inflammatory markers Effects of P25 and LPS on NO production Nos2/Gapdh mrna Nitrites, M LPS ng/ml P25 8 µg/cm 2 5 * 24h * 48h ** ### ### $ $$ *p <.5 vs. Untreated cultures ### p <.1 vs. cultures treated with LPS 1 ng/ml alone $ p <.5 vs. LPS 1 ng /ml alone **p <.1, p <.1 vs. untreated cultures ## p <.1 vs. cultures treated with LPS 1 ng/ml alone $$ p <.1 vs. LPS 1 ng /ml 14kDa- 4kDa- 48h LPS 1 ng/ml P25 µg/cm alone. P25 synergize the LPS-mediated stimulation of Nos2 gene/protein expression and of NO production Nos2 - Actin

9 RESULTS Inflammatory markers Effects of P25 and LPS on cytokine secretion TNF- (pg/ml) TNF-alpha 48h $$$ $$$ LPS LPS ng/ml ng/ml TiOP25 2 NPs 8 8µg/cm g/cm IL-6 (pg/ml) IL-6 $$$ LPS LPS ng/ml TiOP25 2 NPs 8 8µg/cm g/cm ns 48h + + $$ + P25 synergize also the secretion of inflammatory cytokines induced by LPS *p <.5, p <.1 vs. untreated cultures; ## p <.1, ### p <.1 vs. cultures treated with LPS 1 ng/ml alone; $ p <.5, $$$ p <.1 vs. LPS 1 ng/ml alone

10 A comparison between the effects mediated by P25 and NAMA41 Data 1 Nitrites, M LPS 1 ng/ml NAMA41 µg/cm The synergistic effect of P25 on LPSdependent macrophage activation is shared by NAMA41 (another industrial preparation of TiO 2 NPs) ns 48h ** RESULTS Inflammatory markers ns ## ### Nos2/Gapdh mrna TNF- (pg/ml) LPS 1 ng/ml NAMA41 8 µg/cm 2 P25 8 µg/cm 2 Data 2 ** 24h 48h ** ### * ### ### ### + + **p <.1, p <.1 vs. untreated cultures; ## p <.1, ### p <.1 vs. cultures treated with LPS 1 ng/ml alone.

11 CD14 RESULTS Mechanism characterization Role of TLR4 on the P25 -mediated synergistic induction of Nos2: effect of polymyxin B LPS Polymyxin B Nos2-48h OUT TLR4 Actin - IN ADAPTOR LPS 1 ng/ml P25 8 µg/cm Polymyxin 5 µg/ml Pro-inflammatory gene transcription Suppression of Nos2 induction by Polymyxin P25 enhance macrophage activation by LPS via a TLR4-dependent mechanism

12 w/o inhibitor Cytochalasin 5µg/ml RESULTS Mechanism characterization Effect of cytoskeletal disorganization on NO production and P25 internalization P25 1 µg/cm 2 + LPS 1 ng/ml Cytochalasin blokes the endocytosis of P25

13 Nitrites, µm RESULTS Mechanism characterization Effect of cytoskeletal disorganization on NO production and P25 internalization 48h Nitrites, M W/O w/o Ihibitor Inhibitor Cytochalasin 5 g/ml ### * ns ns ** ns ### ### Endocytosis blockade inhibits the synergistic effect of P25 on LPSdependent NO production Involvement of an intracellular site LPS ng/ml P25 NPs µg 8 g/cm 8/cm *p <.5, **p <.1,p <.1 vs. untreated cultures; ###p <.1 vs. cultures treated under the same conditions without the inhibitor

RESULTS Mechanism characterization Role of MKKs in the LPS and P25 effects Tubp-ERK 1/2- ERK 1/2- Tub- 6h LPS 1 ng/ml + + P25 8 µg/cm 2 + + p-p38/(p38/tub) Fold change 2 15 1 5

uninhibited values) values) Nitrites (% of uninhibited values) 2 2 15 15 1 1 5 5 2 15 1 5 NO inhibitor NO inhibitor LPS 1 ng/ml U126 1 M ns SB2358 2 M LPS 1 ng/ml + P25 8 g/cm 2

14 RESULTS Mechanism characterization Role of MKKs in the LPS and P25 effects Tubp-ERK 1/2- ERK 1/2- Tub- 6h LPS 1 ng/ml + + P25 8 µg/cm p-p38/(p38/tub) Fold change p-p38/(p38/tub) Fold chamge p-p38- p h LPS 1 ng/ml + + P25 8 µg/cm LPS-P25 synergy involves p38 but not ERK 1/2 MAPK Nitrites Nitrites (% of (% uninhibited of uninhibited values) values) Nitrites (% of uninhibited values) NO inhibitor NO inhibitor LPS 1 ng/ml U126 1 M ns SB M LPS 1 ng/ml + P25 8 g/cm 2 NO inhibitor LPS 1 ng/ml U126 1 M ** U126 1 M SB M SB M **p <.1 and p <.1 vs. cultures incubated with the same doses of LPS and TiO2 NPs in the absence of inhibitors ns

15 SUMMING UP TiO 2 NP synergize LPS inflammogenic activity - Enhanced NO production, pro-inflammatory gene expression, cytokine secretion The effect requires TLR4 signalling, phagocytosis and the phosphorylation of p38 MAPK - TLR4 inhibitors, blockade of TiO 2 NP internalization and Inhibition of p38 phosphorylation prevent macrophage activation Hypothesis Do TiO 2 NP bind LPS?

C -7 min P25 + LPS corona Free LPS Repeated washes and centrifigations LPS hard

16 PRELIMINARY RESULTS P25 -LPS binding Assessment of LPS corona on P25 by SDS-PAGE and Silver Staining P25 (1 µg/ml) LPS (1ng/ml) 1h (37 C) Centrifugation -1 rpm -4 C -7 min P25 + LPS corona Free LPS Repeated washes and centrifigations LPS hard corona TiO 2 NP bind LPS and are likely responsible for LPS intracellular delivery

17 SUMMING UP TiO 2 NP are able to deliver high amounts of LPS in to the cell - LPS corona formation on TiO 2 has been demonstrated TiO 2 NP as TROJAN HORSES

TLR4 receptors on plasma membrane Biological effects depend (also) from the bioactive molecules present

18 CONCLUSIONS A working model. Nanomaterials change the biopersistence and/or bioavailability of PAMPs Free LPS Out-door activation of TLR4 receptors on plasma membrane Biological effects depend (also) from the bioactive molecules present in the tissue (contaminants, PAMP, etc.) Exploitable for modulating inflammatory responses? Free LPS + TiO Out-door + In-door activation of TLR4 receptors in endosomal compartments

19 Thank you all..!!

Osmotic stress induces the phosphorylation of WNK4 Ser575 via the p38mapk-mk pathway. Tokyo, Hongo, Bunkyo-ku, Tokyo , Japan

Osmotic stress induces the phosphorylation of WNK4 Ser575 via the p38mapk-mk pathway Junichi Maruyama 1, 2, Yumie Kobayashi 1, Tsuyoshi Umeda 1, Alain Vandewalle 3, Kohsuke Takeda 1, 4, Hidenori Ichijo