Prolonged Release and Functionality of Interleukin-10 Encapsulated within PLA-PEG Nanoparticles

Abstract

Inflammation, as induced by the presence of cytokines and chemokines, is an integral part of chlamydial infections. The anti-inflammatory cytokine, interleukin (IL)-10, has been reported to efficiently suppress the secretion of inflammatory cytokines triggered by Chlamydia in mouse macrophages. Though IL-10 is employed in clinical applications, its therapeutic usage is limited due to its short half-life. Here, we document the successful encapsulation of IL-10 within the biodegradable polymeric nanoparticles of PLA-PEG (Poly (lactic acid)-Poly (ethylene glycol), to prolong its half-life. Our results show the encapsulated-IL-10 size (~238 nm), zeta potential (−14.2 mV), polydispersity index (0.256), encapsulation efficiency (~77%), and a prolonged slow release pattern up to 60 days. Temperature stability of encapsulated-IL-10 was favorable, demonstrating a heat capacity of up to 89 °C as shown by differential scanning calorimetry analysis. Encapsulated-IL-10 modulated the release of IL-6 and IL-12p40 in stimulated macrophages in a time- and concentration-dependent fashion, and differentially induced SOCS1 and SOCS3 as induced by chlamydial stimulants in macrophages. Our finding offers the tremendous potential for encapsulated-IL-10 not only for chlamydial inflammatory diseases but also biomedical therapeutic applications.

Suppressors of Cytokine Signaling (SOCS)1 and SOCS3 Proteins Are Mediators of Interleukin-10 Modulation of Inflammatory Responses Induced byChlamydia muridarumand Its Major Outer Membrane Protein (MOMP) in Mouse J774 Macrophages

“…Herein, the potent IL-10 anti-inflammatory function [31,93,94] is now validated for chlamydial inflammation by impeding the release of not only cytokines but also chemokines in macrophages, which are congruent with our previous findings [27,41]. Many investigators have reported on IL-10 inhibitory actions in macrophages exposed to protozoans (Leishmania braziliensis and Leishmania chagasi), viruses (Tacaribe Virus), fungal and bacteria (Chlamydia spp., Borrelia burgdorferi, Helicobacter pylori, Staphylococcus aureus, Streptococcus pneumoniae, and Yersinia enterocolitica) [95].…”

“…Cm [strain Nigg II; previously called C. trachomatis mouse pneumonitis (MoPn) biovar] expressed as inclusion forming units (IFU/mL) was purchased from Virusys Corporation (Taneytown, MD, USA) [ 41 ]. The purified live Cm elementary bodies (EBs) were suspended in Sucrose-Phosphate Glutamic acid (SPG) buffer and stored in small aliquots at -80°C until used.…”

“…It is well-known that SOCS1 and SOCS3 are rapidly induced by TLR agonists [108,109], which in part explain their induction by a variety of bacterial pathogens, including Borrelia burgdorferi [39], Listeria monocytogenes [110], Mycobacterium bovis [111], M. tuberculosis [112], Salmonella enterica [113], and S. aureus [114], or bacterium-derived substances such as LPS [115,116] and CpG-DNA [117]. Our previous [41] and current findings demonstrate that Chlamydia and its MOMP can differentially induce SOCS1 and SOCS3 in macrophages.…”

“…The resulting RNA samples were transcribed into complementary deoxyribonucleic acid (cDNA) using the High Capacity cDNA Reverse Transciption Kit (Applied Biosystems, Foster City, CA, USA). Next, TaqMan® qRT-PCR was employed as described [42] [19,26,41]. Amplification of gene transcripts was performed according to the manufacturer's protocol using ABI ViiA™ 7 realtime PCR (Applied Biosystems) and standard amplification conditions.…”

“…This data has important therapeutic implications in targeting IL-10 and SOCS in macrophages and, therefore, could be beneficial for controlling Chlamydia and other bacterial inflammatory diseases. Notably, the reciprocal regulation of SOCS1 and SOCS3 in macrophage by PLA-PEG-encapsulated IL-10 to prolong its biological half-life warrants more studies [41]. Our future research encompasses studying the in vivo role of SOCS1 and SOCS3 in the IL-10-mediated inhibition of chlamydial-induced genital inflammation to expound on the roles of these regulators in the remediation of Chlamydia inflammatory etiologies.…”