A Multiscale Study of Phosphorylcholine Driven Cellular Phenotypic Targeting.

Phenotypic targeting requires the ability of the drug delivery system to discriminate over cell populations expressing a particular receptor combination. Such selectivity control can be achieved using multiplexed-multivalent carriers often decorated with multiple ligands. Here, we demonstrate that the promiscuity of a single ligand can be leveraged to create multiplexed-multivalent carriers achieving phenotypic targeting. We show how the cellular uptake of poly(2-(methacryloyloxy)ethyl phosphorylcholine)-poly(2-(diisopropylamino)ethyl methacry-late) (PMPC-PDPA) polymersomes varies depending on the receptor expression among different cells. We investigate the PMPC-PDPA polymersome insertion at the single chain/receptor level using all-atom molecular modeling. We propose a theoretical statistical mechanics-based model for polymersome-cell association that explicitly considers the interaction of the polymersome with the cell glycocalyx shedding light on its effect on the polymersome binding. We validate our model experimentally and show that the binding energy is a nonlinear function, allowing us to tune the interaction by varying the radius and degree of polymerization. Finally, we show that PMPC-PDPA polymersomes can be used to target monocytes in vivo due to their promiscuous interaction with SRB1, CD36, and CD81.

Polymersomes Eradicating Intracellular Bacteria.

Mononuclear phagocytes such as monocytes, tissue-specific macrophages, and dendritic cells are primary actors in both innate and adaptive immunity. These professional phagocytes can be parasitized by intracellular bacteria, turning them from housekeepers to hiding places and favoring chronic and/or disseminated infection. One of the most infamous is the bacteria that cause tuberculosis (TB), which is the most pandemic and one of the deadliest diseases, with one-third of the world's population infected and an average of 1.8 million deaths/year worldwide. Here we demonstrate the effective targeting and intracellular delivery of antibiotics to infected macrophages both in vitro and in vivo, using pH-sensitive nanoscopic polymersomes made of PMPC-PDPA block copolymer. Polymersomes showed the ability to significantly enhance the efficacy of the antibiotics killing Mycobacterium bovis, Mycobacterium tuberculosis, and another established intracellular pathogen, Staphylococcus aureus. Moreover, they demonstrated to easily access TB-like granuloma tissues-one of the harshest environments to penetrate-in zebrafish models. We thus successfully exploited this targeting for the effective eradication of several intracellular bacteria, including M. tuberculosis, the etiological agent of human TB.

Macrophage Targeting pH Responsive Polymersomes for Glucocorticoid Therapy.

Glucocorticoid (GC) drugs are the cornerstone therapy used in the treatment of inflammatory diseases. Here, we report pH responsive poly(2-methacryloyloxyethyl phosphorylcholine)-poly(2-(diisopropylamino)ethyl methacrylate) (PMPC-PDPA) polymersomes as a suitable nanoscopic carrier to precisely and controllably deliver GCs within inflamed target cells. The in vitro cellular studies revealed that polymersomes ensure the stability, selectivity and bioavailability of the loaded drug within macrophages. At molecular level, we tested key inflammation-related markers, such as the nuclear factor-κB, tumour necrosis factor-α, interleukin-1ß, and interleukin-6. With this, we demonstrated that pH responsive polymersomes are able to enhance the anti-inflammatory effect of loaded GC drug. Overall, we prove the potential of PMPC-PDPA polymersomes to efficiently promote the inflammation shutdown, while reducing the well-known therapeutic limitations in GC-based therapy.

Metabolically Active, Fully Hydrolysable Polymersomes.

The synthesis and aqueous self-assembly of a new class of amphiphilic aliphatic polyesters are presented. These AB block polyesters comprise polycaprolactone (hydrophobe) and an alternating polyester from succinic acid and an ether-substituted epoxide (hydrophile). They self-assemble into biodegradable polymersomes capable of entering cells. Their degradation products are bioactive, giving rise to differentiated cellular responses inducing stromal cell proliferation and macrophage apoptosis. Both effects emerge only when the copolymers enter cells as polymersomes and their magnitudes are size dependent.

Hyaluronic acid-conjugated pH-sensitive liposomes for targeted delivery of prednisolone on rheumatoid arthritis therapy.

AIM: The treatment of rheumatoid arthritis remains a challenge as available therapies still entail the risk of deleterious off-target effects. The present study describes hyaluronic acid-conjugated pH-sensitive liposomes as an effective drug delivery-targeting strategy to synovial cells. MATERIALS & METHODS: Therapeutic, cytotoxic and targeting potential of developed liposomes were studied in vitro using macrophages and fibroblasts cell lines. RESULTS & CONCLUSION: Results suggest an enhanced cellular uptake of conjugated liposomes, mainly mediated by caveolae- and clathrin-dependent endocytosis. In vitro release studies demonstrated that prednisolone was preferentially released under acidic conditions mimicking intracellular endosomal compartments. Overall, results revealed that conjugated pH-sensitive liposomes are a promising nanoapproach for the targeted delivery of prednisolone within inflamed synovial cells for rheumatoid arthritis treatment.

Oxaprozin-Loaded Lipid Nanoparticles towards Overcoming NSAIDs Side-Effects.

PURPOSE: Nanostructured Lipid Carriers (NLCs) loading oxaprozin were developed to address an effective drug packaging and targeted delivery, improving the drug pharmacokinetics and pharmacodynamics properties and avoiding the local gastric side-effects. Macrophages actively phagocyte particles with sizes larger than 200 nm and, when activated, over-express folate beta receptors - features that in the case of this work constitute the basis for passive and active targeting strategies. METHODS: Two formulations containing oxaprozin were developed: NLCs with and without folate functionalization. In order to target the macrophages folate receptors, a DSPE-PEG2000-FA conjugate was synthesized and added to the NLCs. RESULTS: These formulations presented a relatively low polydispersity index (approximately 0.2) with mean diameters greater than 200 nm and zeta potential inferior to -40 mV. The encapsulation efficiency of the particles was superior to 95% and the loading capacity was of 9%, approximately. The formulations retained the oxaprozin release in simulated gastric fluid (only around 10%) promoting its release on simulated intestinal fluid. MTT and LDH assays revealed that the formulations only presented cytotoxicity in Caco-2 cells for oxaprozin concentrations superior to 100 µM. Permeability studies in Caco-2 cells shown that oxaprozin encapsulation did not interfered with oxaprozin permeability (around 0.8 × 10(-5) cm/s in simulated intestinal fluid and about 1.45 × 10(-5) cm/s in PBS). Moreover, in RAW 264.7 cells NLCs functionalization promoted an increased uptake over time mainly mediated by a caveolae uptake mechanism. CONCLUSIONS: The developed nanoparticles enclose a great potential for oxaprozin oral administration with significant less gastric side-effects.

Non-Biologic Nanodelivery Therapies for Rheumatoid Arthritis.

Rheumatoid arthritis is a common chronic inflammatory disease characterized by progressive bone and cartilage destruction causing severe functional limitations, increased morbidity and mortality rate, which results in a strong negative socioeconomic impact. Current therapies only slow the progression of the disease and try to enhance quality of life. Furthermore, such therapies present several drawbacks due to the adverse effects caused by the lack of selectively of the drugs and frequent and long-term dosing that lead to patient non-compliance. Drug delivery systems based on nanocarriers represent a promising approach to overcome the current therapeutic limitations because they can selectively carry drugs to inflamed synovium allowing for improved drug efficacy, thereby reducing the biodistribution of anti-rheumatic drugs. Additionally, controlled drug release can lead to the reduction of drug dosages. The increasing interest and confidence that nanocarriers can revolutionize the treatment of rheumatoid arthritis has led to an increased number of investigations in this field. In this context, the present review focuses on drug delivery system strategies for non-biological drugs developed for the treatment of rheumatoid arthritis.