title: Pulmonary surfactant protein SP-D opsonises carbon nanotubes and augments their phagocytosis and subsequent pro-inflammatory immune response.
abstract: Carbon nanotubes (CNTs) are increasingly being developed for use in biomedical applications, including drug delivery. One of the most promising applications under evaluation is in treating pulmonary diseases such as tuberculosis. Once inhaled or administered, the nanoparticles are likely to be recognised by innate immune molecules in the lungs such as hydrophilic pulmonary surfactant proteins. Here, we set out to examine the interaction between surfactant protein D (SP-D), a key lung pattern recognition molecule and CNTs, and possible downstream effects on the immune response via macrophages. We show here that a recombinant form of human SP-D (rhSP-D) bound to oxidised and carboxymethyl cellulose (CMC) coated CNTs via its C-type lectin domain and enhanced phagocytosis by U937 and THP-1 macrophages/monocytic cell lines, together with an increased pro-inflammatory response, suggesting that sequestration of SP-D by CNTs in the lungs can trigger an unwanted and damaging immune response. We also observed that functionalised CNTs, opsonised with rhSP-D, continued to activate complement via the classical pathway, suggesting that C1q, which is the recognition sub-component of the classical pathway, and SP-D have distinct pattern recognition sites on the CNTs. Consistent with our earlier reports, complement deposition on the rhSP-D opsonised CNTs led to dampening of the pro-inflammatory immune response by THP-1 macrophages, as evident from qPCR, cytokine array and NF-κB nuclear translocation analyses. This study highlights the importance of understanding the interplay between innate immune humoral factors including complement in devising nanoparticle based drug delivery strategies.
authors.affiliation: Department of Life Sciences, College of Health and Life Sciences, Brunel University London, Uxbridge UB8 3PH, UK. uday.kishore@brunel.ac.uk ukishore@hotmail.com and Neuro Imaging, MIRA Institute, University of Twente, Enschede, The Netherlands.
authors.forename: Kirsten M
authors.initials: KM
authors.lastname: Pondman
authors.affiliation: Department of Life Sciences, College of Health and Life Sciences, Brunel University London, Uxbridge UB8 3PH, UK. uday.kishore@brunel.ac.uk ukishore@hotmail.com and Faculty of Science, Engineering and Computing, Kingston University Penrhyn Road, Kingston upon Thames, Surrey, KT1 2EE, UK.
authors.forename: Basudev
authors.initials: B
authors.lastname: Paudyal
authors.affiliation: Department of Pharmacology, University of Oxford, Mansfield Road, Oxford, OX1 3QT, UK.
authors.forename: Robert B
authors.identifier: http://orcid.org/0000-0002-2855-7455
authors.initials: RB
authors.lastname: Sim
authors.affiliation: Department of Life Sciences, College of Health and Life Sciences, Brunel University London, Uxbridge UB8 3PH, UK. uday.kishore@brunel.ac.uk ukishore@hotmail.com.
authors.forename: Anuvinder
authors.initials: A
authors.lastname: Kaur
authors.affiliation: Department of Life Sciences, College of Health and Life Sciences, Brunel University London, Uxbridge UB8 3PH, UK. uday.kishore@brunel.ac.uk ukishore@hotmail.com.
authors.forename: Lubna
authors.initials: L
authors.lastname: Kouser
authors.affiliation: Department of Life Sciences, College of Health and Life Sciences, Brunel University London, Uxbridge UB8 3PH, UK. uday.kishore@brunel.ac.uk ukishore@hotmail.com.
authors.forename: Anthony G
authors.initials: AG
authors.lastname: Tsolaki
authors.affiliation: Faculty of Science, Engineering and Computing, Kingston University Penrhyn Road, Kingston upon Thames, Surrey, KT1 2EE, UK.
authors.forename: Lucy A
authors.initials: LA
authors.lastname: Jones
authors.affiliation: Bioengineering Department and Krasnow Institute for Advanced Study, George Mason University, Fairfax, 22030 Virginia, USA.
authors.forename: Carolina
authors.initials: C
authors.lastname: Salvador-Morales
authors.affiliation: Department of Biochemistry, College of Science, King Saud University, Riyadh, Saudi Arabia.
authors.forename: Haseeb A
authors.initials: HA
authors.lastname: Khan
authors.affiliation: Neuro Imaging, MIRA Institute, University of Twente, Enschede, The Netherlands.
authors.forename: Bennie
authors.initials: B
authors.lastname: Ten Haken
authors.affiliation: Department of Life Sciences, College of Health and Life Sciences, Brunel University London, Uxbridge UB8 3PH, UK. uday.kishore@brunel.ac.uk ukishore@hotmail.com.
authors.forename: Gudrun
authors.initials: G
authors.lastname: Stenbeck
authors.affiliation: Department of Life Sciences, College of Health and Life Sciences, Brunel University London, Uxbridge UB8 3PH, UK. uday.kishore@brunel.ac.uk ukishore@hotmail.com.
authors.forename: Uday
authors.initials: U
authors.lastname: Kishore
mesh_terms: D015922:Complement C1q / Q000737:chemistry; D003171:Complement Pathway, Classical; D016207:Cytokines / Q000378:metabolism; D006801:Humans; D008264:Macrophages / Q000166:cytology*; D037742:Nanotubes, Carbon / Q000737:chemistry*; D010587:Phagocytosis; D037663:Pulmonary Surfactant-Associated Protein D / Q000737:chemistry*; D011994:Recombinant Proteins / Q000737:chemistry; D000074084:THP-1 Cells; D014157:Transcription Factors / Q000378:metabolism; D059467:Transcriptome; D020298:U937 Cells
chemical_list: D016207:Cytokines; D037742:Nanotubes, Carbon; D037663:Pulmonary Surfactant-Associated Protein D; D011994:Recombinant Proteins; D014157:Transcription Factors; D015922:Complement C1q