Alginate Microspheres Elicit Innate M1-Inflammatory Response in Macrophages Leading to Bacillary Killing.

We examined the role of drug-free inhalable alginate microspheres (A-MS) on phagocytosis efficiency and subsequent immune cell activation in Escherichia coli-infected THP-1-derived macrophages. Alginate particles have been widely investigated as carriers for prolonged delivery of bioactive (i.e., drugs, diagnostics, and vaccines). A-MS were fabricated by industry scalable spray-congealing process using divalent cation-induced gelification. E. coli-infected macrophages (multiplicity of infection (MOI 1:10) were treated with drug-free A-MS, where we found a consistent moderate reduction in bacillary viability. Particles were more efficiently and rapidly phagocytized by infected macrophages as compared with normal macrophage cells. Subsequently, A-MS induced markers of M1 macrophage responses and stimulated the processing and secretion of pro-inflammatory cytokines (IL-6, IL-12). It also notably augmented the generation of reactive oxygen species (ROS) and nitric oxide (NO) in infected cells. Results illustrate that, the blank A-MS (without a drug payload) able to moderately check the growth of intracellular E. coli (without significant cytotoxicity) by modulating the M1 inflammatory response by host cells. This "added value" can be utilized in the design and development of therapeutic system with the additional advantage of immune-modulatory activity, in addition to serving as a drug carrier. PMID: 31250260 [PubMed - in process]
Source: AAPS PharmSciTech - Category: Drugs & Pharmacology Authors: Tags: AAPS PharmSciTech Source Type: research