By Pritam Roy November 21, 2022 Reviewed by Susha Cheriyedath, M.Sc.
In a paper published in the Journal of Controlled Release, researchers used three types of porous nanoparticles (NPs), including porous cross-linked cyclodextrin carriers (CD-NPs), mesoporous magnesium phosphate carriers (MPC-NPs), and mesoporous silica ( MSN). ) to target necrosulfonamide (NSA), a novel inhibitor of gasdermin D (GSDMD) in both mouse and human macrophages. All three NPs showed high loading capacities for this effective hydrophobic drug.
Study: Inhibition of IL-1β release from macrophages targeted with necrosulfonamide-loaded porous nanoparticles. Image credit: urfin/Shutterstock.com
Time-lapse observations using high-throughput live-cell fluorescence microscopy were used to monitor NSA intracellular delivery and cellular uptake. The findings showed rapid nanoparticle uptake and efficient targeted delivery of NSA to phagocytic cells. In particular, a potent cytostatic impact was observed when macrophage cell lines were exposed to free NSA.
Functional assays revealed that CD-NP, followed by MSN-NP, had the most significant suppressive influence on human macrophages when used for NSA administration. In contrast, cell growth was less affected when NSA was administered via nanoparticle carriers. A significant concentration-dependent inhibition of IL-1β cytokine secretion from freshly differentiated human and primary murine macrophages was observed when NSA-loaded nanoparticles were used.
Furthermore, when loaded with NSA, MPC-NP inhibited the metabolic activities of macrophages. Thus, in this work, the authors illustrated the efficiency of hydrophobic drug delivery to macrophages to inhibit inflammatory responses using porous nanoparticles.
Understand the feasibility of targeting NSA with the help of NP
An organism’s physiological response to infections is inflammation, which is crucial for defense against pathogens. Chronic inflammation, however, can be detrimental to a number of diseases, including autoimmune and cardiovascular conditions and certain cancers.
The cytokines interleukin (IL)-18 and IL-1β, secreted by immune cells such as macrophages when activated by endogenous stress signals or pathogen danger signals, are two primary mediators of inflammation. These cytokines can initiate and maintain inflammatory processes throughout the body.
Immune cells release IL-1β and IL-18 as a result of a sequential process. Activation of caspase-1 by proteolytic cleavage begins with a cascade of intracellular processes triggered by the identification of viral or bacterial components by sensory proteins, which serve as danger signals. The proforms of IL-18 and IL-1β, as well as the pore-forming protein GSDMD, are then cleaved by activated caspase-1.
Ultimately, pore formation caused by GSDMD leads to the production of proinflammatory mediators such as IL-18, IL-1β, adenosine triphosphate (ATP), and high-mobility group box 1 (HMGB1), which causes pyroptosis , a type of inflammatory cell death.
In this study, the authors investigated the feasibility of porous NP targeting NSA in macrophages. In addition to their ability to cause inflammation, macrophages can ingest small particles, such as dead cells or bacteria, through phagocytosis.
The authors took advantage of this function by using NPs as a means to deliver NSA precisely to macrophages. The findings demonstrated that these NSA-loaded carriers enabled solvent-free NSA administration that prevented the release of proinflammatory IL-1β by exposing human and murine macrophages.
Three in-house generated nanocarriers with various compositions and structures were evaluated. MSN, newly created CD-NP and MPC-NP formed the nanocarriers. NSA administration efficiency, NP cellular uptake, and toxicity were investigated using primary mouse macrophage and splenocyte cell lines. In addition, we evaluated the efficiency of cytokine inhibition after NSA administration using human monocyte-derived macrophages (MDM) and murine bone marrow-derived macrophages (BMDM).
Experimental assembly
Three different materials were tested for the efficiency of NSA delivery to immune cells. All the porous nanocarriers used in this study were biocompatible and were selected for their advantageous features in solvent-free sustained drug delivery. The excellent NP stability, which allowed years of storage in ethanolic solutions, made possible a possible “off-the-shelf” application.
The first category of materials used, MSNs, was continuously developed over the years and applied in numerous biomedical applications due to their exceptional flexibility in terms of pore and particle size, NP constitution, and functionalization. molecular The second category of materials consisted of novel NPs made of cyclodextrin (CD-NPs). The third material was magnesium phosphate citrate NP (MPC-NP), which was fully biogenic.
Because macrophages specialized in the uptake of particulate material, their use as a delivery mechanism allowed for specific targeting of these cells. The findings showed that the hydrophobic NSA could be loaded onto three different nanocarriers with high loading, allowing the distribution of NSA without the need for solvents. Thus, the NSA cargo carried by MSN and CD particles was rapidly ingested by macrophages and delivered to the cells.
A large percentage of dendritic cells and macrophages were positive for CD particles after 24 hours of exposure to the mixed population of immune cells. Interestingly, after 24 hours, a significant portion of B lymphocyte cells were also positive for CD particles. In contrast, some non-phagocytic T cells were positive for CD particles. Thus, these findings demonstrated that targeting macrophages and dendritic cells, the critical inflammatory initiators, through porous NP delivery of NSA could be a successful strategy.
MSN and CD NPs were more tolerable to macrophages when loaded with NSA than free NSA compounds, which were aggregated in an aqueous medium. In contrast, even at lower concentrations of NSA, NSA-loaded MPC particles completely prevented the metabolic activity of macrophages. MPC particles required small amounts of surfactant, which could be harmful to these cells, to load NSA. Therefore, distribution by porous NP could improve the compatibility of NSA composites with macrophages, except for MPC particles.
NSA-loaded porous NPs and the future of human inflammatory responses
The authors used macrophage cell lines and freshly differentiated primary macrophages from human donors and mice in several in vitro assays. They also showed excellent compatibility of the unloaded carriers with the employed cell lines, even in long-term incubation investigations of more than 45 hours.
Two excellent options for NSA delivery were identified by the proposed particle screening in the form of CD-CDI and MSN NPs. These particles could deliver significant concentrations of the hydrophobic molecule to phagocytic cells without adding a capping layer, thus suppressing the IL-1β cytokine. In addition, these NPs were simple to synthesize, storable, scalable, and biodegradable.
The findings showed that MSN NPs were rapidly taken up by macrophages in large amounts. However, CD-NP was much more efficient in intracellular release of NSA, contributing to more significant suppression of IL-1β cytokine.
Here, the authors concentrated on the characterization of various forms of NSA-NPs and their impact on macrophage cell lines and other immune cells when tested in vitro. The findings demonstrated the potential of porous biocompatible NPs for the efficient and targeted delivery of potentially lethal hydrophobic drugs to control inflammatory responses in human and primary murine immune cells. Furthermore, these NP formulations offered further advantages in vivo.
reference
Boersma, B et al. (2022). Inhibition of IL-1β release from macrophages targeting necrosulfonamide-loaded porous nanoparticles. Controlled Release Journal. https://www.sciencedirect.com/science/article/pii/S0168365922006666?via%3Dihub
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