Calcium-sensing receptor-mediated NLRP3 inflammasome response to calciprotein particles drives inflammation in rheumatoid arthritis.

Increased extracellular Ca2+ concentrations ([Ca2+]ex) trigger activation of the NLRP3 inflammasome in monocytes through calcium-sensing receptor (CaSR). To prevent extraosseous calcification in vivo, the serum protein fetuin-A stabilizes calcium and phosphate into 70-100 nm-sized colloidal calciprotein particles (CPPs). Here we show that monocytes engulf CPPs via macropinocytosis, and this process is strictly dependent on CaSR signaling triggered by increases in [Ca2+]ex. Enhanced macropinocytosis of CPPs results in increased lysosomal activity, NLRP3 inflammasome activation, and IL-1ß release. Monocytes in the context of rheumatoid arthritis (RA) exhibit increased CPP uptake and IL-1ß release in response to CaSR signaling. CaSR expression in these monocytes and local [Ca2+] in afflicted joints are increased, probably contributing to this enhanced response. We propose that CaSR-mediated NLRP3 inflammasome activation contributes to inflammatory arthritis and systemic inflammation not only in RA, but possibly also in other inflammatory conditions. Inhibition of CaSR-mediated CPP uptake might be a therapeutic approach to treating RA.

Spherical and Worm-Like Micelles from Fructose-Functionalized Polyether Block Copolymers.

This paper presents the synthesis and characterization of d-fructose modified poly(ethylene glycol) (Fru-PEG) and fructose modified poly(ethylene glycol)-block-poly(ethyl hexyl glycidyl ether) (Fru-PEG-b-PEHG) that are both prepared by initiation with isopropyliden protected fructose, followed by deprotection of the sugar. The block copolymers are self-assembled into micelles, and are subsequently characterized by cryo-TEM and dynamic light scattering. The fluorescent dye Nile red is encapsulated as a model hydrophobic compound and fluorescent marker to perform initial uptake tests with breast cancer cells. The uptake of sugar and nonsugar decorated micelles is compared.

Polymersomes with Endosomal pH-Induced Vesicle-to-Micelle Morphology Transition and a Potential Application for Controlled Doxorubicin Delivery.

In order to obtain a novel, pH responsive polymersome system, a series of pH responsive block copolymers were synthesized via the reversible addition-fragmentation chain transfer (RAFT) polymerization of 3,4-dihydro-2H-pyran (DHP) protected 2-hydroxyethyl methacrylate (HEMA) (2-((tetrahydro-2H-pyran-2-yl)oxy)ethyl methacrylate (THP-HEMA)) and 2-(dimethylamino) ethyl methacrylate (DMAEMA) using p(THP-HEMA) as a macro chain transfer agent (mCTA). The degree of polymerization (DP) of the p(THP-HEMA) block was fixed to 35, whereas the DP of the p(DMAEMA) block was systematically varied from 21 to 50. In aqueous solution, the block copolymer with the shortest p(DMAEMA) block (DP = 21) self-assembled into vesicles, while the polymer with 30 units of p(DMAEMA) formed a mixture of micelles and vesicles. The polymer with the longest p(DMAEMA) block (DP = 50) formed exclusively micelles. The corresponding polymersomes exhibited a morphology transition from vesicles at neutral pH values to micelles upon lowering the pH value down to endosomal pH value as investigated by DLS and cryo-TEM. The capability of polymersomes to encapsulate both hydrophobic (e.g., Nile Red) and hydrophilic (e.g., doxorubicin hydrochloride (DOX·HCl)) cargos was verified by in vitro studies. Drug release studies demonstrated that the DOX·HCl release is significantly accelerated under acidic pH values compared to physiological conditions. Cytotoxicity studies revealed that DOX·HCl loaded polymersomes exhibited an efficient cell death comparable to free DOX·HCl. CLSM and flow cytometry studies showed that DOX·HCl loaded vesicles were easily taken up by L929 cells and were mainly located in the cytoplasm and cell nuclei.

Mission ImPOxable - or the unknown utilization of non-toxic poly(2-oxazoline)s as cryoprotectants and surfactants at the same time.

Polymer based nanoparticles offer great opportunities for diverse applications, i.e. their drug delivery potential is promising. However, their major drawback is identified in preparation via the nanoemulsion technique, which is needed for the encapsulation of hydrophilic drugs and whereby the utilization of surfactants, e.g. poly(vinyl alcohol) (PVA), is mandatory. Furthermore, the preparation of nanoparticles is critical due to the need of lyophilization for storage. For this reason it is common to use cryoprotectants, which are usually sugar based. In the current study, we present the use of non-toxic, water-soluble poly(2-oxazoline)s (P(Ox)s) in terms of polymeric nanoparticle stabilizers for preparation, purification, and lyophilization. The nanoparticles were characterized via dynamic light scattering (DLS) and cryo-transmission electron microscopy (cryoTEM). The use of hydrophilic P(Ox)s with a degree of polymerization of about 60 yielded stable nanoparticles. For the preparation via nanoemulsion a PDI below 0.2 could be obtained after adjustment of the surfactant concentration. All nanoparticles were in the size range of 100 to 200 nm according to DLS. Furthermore, the addition of P(Ox) was beneficial during particle purification via centrifugation and filtration as well as lyophilization, yielding nanoparticles with a PDI below 0.3 as determined via DLS and confirmed via cryoTEM measurements. Cytotoxicity, hemolysis and erythrocyte aggregation measurements of these P(Ox)s did not show any harmful effect on the treated cells.