Clofazimine, a lipophilic (log P = 7.66) riminophenazine antibiotic approved by the US Food and Drug Administration (FDA) with a good safety record, was recently identified as a lead hit for cryptosporidiosis through a high-throughput phenotypic screen. Cryptosporidiosis requires fast-acting treatment as it leads to severe symptoms which, if untreated, result in morbidity for infants and small children. Consequently, a fast-releasing oral formulation of clofazimine in a water-dispersible form for pediatric administration is highly desirable. In this work, clofazimine nanoparticles were prepared with three surface stabilizers, hypromellose acetate succinate (HPMCAS), lecithin, and zein, using the flash nanoprecipitation (FNP) process. Drug encapsulation efficiencies of over 92% were achieved. Lyophilization and spray-drying were applied and optimized to produce redispersible nanoparticle powders. The release kinetics of these clofazimine nanoparticle powders in biorelevant media were measured and compared with those of crystalline clofazimine and the currently marketed formulation Lamprene. Remarkably improved dissolution rates and clofazimine supersaturation levels up to 90 times equilibrium solubility were observed with all clofazimine nanoparticles tested. Differential scanning calorimetry indicated a reduction of crystallinity of clofazimine in nanoparticles. These results strongly suggest that the new clofazimine nanoparticles prepared with affordable materials in this low-cost nanoparticle formulation process can be used as viable cryptosporidiosis therapeutics.

Sugar-based polymers have been extensively explored as a means to increase drug delivery systems’ biocompatibility and biodegradation. Here, we review the use of sugar-based polymers for drug delivery applications, with a particular focus on the utility of the sugar component(s) to provide benefits for drug targeting and stimuli-responsive systems. Specifically, numerous synthetic methods have been developed to reliably modify naturally-occurring polysaccharides, conjugate sugar moieties to synthetic polymer scaffolds to generate glycopolymers, and utilize sugars as a multifunctional building block to develop sugar-linked polymers. The design of sugar-based polymer systems has tremendous implications on both the physiological and biological properties imparted by the saccharide units and are unique from synthetic polymers. These features include the ability of glycopolymers to preferentially target various cell types and tissues through receptor interactions, exhibit bioadhesion for prolonged residence time, and be rapidly recognized and internalized by cancer cells. Also discussed are the distinct stimuli-sensitive properties of saccharide-modified polymers to mediate drug release under desired conditions. Saccharide-based systems with inherent pH- and temperature-sensitive properties, as well as enzyme-cleavable polysaccharides for targeted bioactive delivery, are covered. Overall, this work emphasizes inherent benefits of sugar-containing polymer systems for bioactive delivery.

Inspired by high promise using naturally occurring antimicrobial peptides (AMPs) to treat infections caused by antimicrobial-resistant bacteria, cationic amphiphiles (CAms) were strategically designed as synthetic mimics to overcome associated limitations, including high manufacture cost and low metabolic stability. CAms with facially amphiphilic conformation were expected to demonstrate membrane-lytic properties and thus reduce tendency of resistance development. By systematically tuning the hydrophobicity, CAms with optimized compositions exhibited potent broad-spectrum antimicrobial activity (with minimum inhibitory concentrations in low μg/mL range) as well as negligible hemolytic activity. Electron microscope images revealed the morphological and ultrastructure changes of bacterial membranes induced by CAm treatment and validated their membrane-disrupting mechanism. Additionally, an all-atom molecular dynamics simulation was employed to understand the CAm-membrane interaction on molecular level. This study shows that these CAms can serve as viable scaffolds for designing next generation of AMP mimics as antimicrobial alternatives to combat drug-resistant pathogens.

The goal of the present study was to elucidate the mechanism by which long non-coding RNA metastasis-associated lung adenocarcinoma transcript 1 (lncRNA MALAT1) promotes inflammation in Parkinson’s disease (PD). 1-Methyl-4-phenyl-1,2,3,6-tetrahydropyridine (MPTP) was used to induce PD development in C57BL/6 mice, and tyrosine hydroxylase (TH) expression was analysed by immunohistochemical analysis. Western blot and qPCR analyses were conducted to assess the expression of protein and mRNA levels, respectively. Lipopolysaccharide/adenosine triphosphate (LPS/ATP) was used to activate microglia in vitro. Chromatin immunoprecipitation (ChIP), RNA pull-down and RNA immunoprecipitation chip (RIP) assays were performed to investigate the interaction among specific molecules. The 3-(4,5-dimethylthiazol-2-yl)-2,5-diphenyltetrazolium bromide (MTT) assay was used to evaluate cell viability and proliferation. Flow cytometry was performed to analyse cell apoptosis after staining. The dichlorofluorescein diacetate (DCFH-DA) assay was used to measure the generation of reactive oxygen species (ROS) in cells. The results showed that MALAT1 was highly expressed in the brains of MPTP-induced PD model mice and in LPS/ATP-induced microglia cells. Knockdown of MALAT1 inhibited elevated nuclear factor (erythroid-derived 2)-like-2 factor (NRF2) expression, thereby inhibiting inflammasome activation and ROS production. MALAT1 was shown to promote neuroinflammation by recruiting enhancer of zeste homologue 2 (EZH2) to the promoter of NRF2, suppressing Nrf2 expression. In summary, MALAT1 epigenetically inhibits NRF2, thereby inducing inflammasome activation and reactive oxygen species (ROS) production in PD mouse and microglial cell models.

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