Inflammatory bowel diseases (IBDs) are often associated with elevated levels of reactive oxygen species (ROS) and highly dysregulated gut microbiota. In this study, we synthesized a polymer of hyaluronic acid–poly(propylene sulfide) (HA-PPS) and developed ROS-scavenging nanoparticles (HPN) that could effectively scavenge ROS. To achieve colon tissue targeting effects, the HPN nanoparticles were conjugated to the surface of modified probiotic Escherichia coli Nissle 1917 (EcN). To enhance the bacteriotherapy of EcN, we encapsulated EcN cells with a poly-norepinephrine (NE) layer that can protect EcN against environmental assaults to improve the viability of EcN in oral delivery and prolong the retention time of EcN in the intestine due to its strong mucoadhesive capability. In the dextran sulfate sodium–induced mouse colitis models, HPN-NE-EcN showed substantially enhanced prophylactic and therapeutic efficacy. Furthermore, the abundance and diversity of gut microbiota were increased after treatment with HPN-NE-EcN, contributing to the alleviation of IBDs.

Immunosuppressive cells residing in the tumor microenvironment, especially tumor associated macrophages (TAMs), hinder the infiltration and activation of T cells, limiting the anti-cancer outcomes of immune checkpoint blockade. Here, we report a biocompatible alginate-based hydrogel loaded with Pexidartinib (PLX)-encapsulated nanoparticles that gradually release PLX at the tumor site to block colony-stimulating factor 1 receptors (CSF1R) for depleting TAMs. The controlled TAM depletion creates a favorable milieu for facilitating local and systemic delivery of anti-programmed cell death protein 1 (aPD-1) antibody-conjugated platelets to inhibit post-surgery tumor recurrence. The tumor immunosuppressive microenvironment is also reprogrammed by TAM elimination, further promoting the infiltration of T cells into tumor tissues. Moreover, the inflammatory environment after surgery could trigger the activation of platelets to facilitate the release of aPD-1 accompanied with platelet-derived microparticles binding to PD-1 receptors for re-activating T cells. All these results collectively indicate that the immunotherapeutic efficacy against tumor recurrence of both local and systemic administration of aPD-1 antibody-conjugated platelets could be strengthened by local depletion of TAMs through the hydrogel reservoir.

Pore-forming Gasdermin protein-induced pyroptosis in tumor cells promotes anti-tumor immune response through the release of pro-inflammatory cytokines and immunogenic substances after cell rupture. However, endosomal sorting complexes required for transport (ESCRT) III-mediated cell membrane repair significantly diminishes the tumor cell pyroptosis by repairing and subsequently removing gasdermin pores. Here, we show that blocking calcium influx-triggered ESCRT III-dependent membrane repair through a biodegradable nanoparticle-mediated sustained release of calcium chelator (EI-NP) strongly enhances the intracellularly delivered GSDMD-induced tumor pyroptosis via a bacteria-based delivery system (VNP-GD). An injectable hydrogel and a lyophilized hydrogel-based cell patch are developed for peritumoral administration for treating primary and metastatic tumors, and implantation for treating inoperable tumors respectively. The hydrogels, functioning as the local therapeutic reservoirs, can sustainedly release VNP-GD to effectively trigger tumor pyroptosis and EI-NP to prevent the ESCRT III-induced plasma membrane repair to boost the pyroptosis effects, working synergistically to augment the anti-tumor immune response.

Antifungal resistance due to upregulation of efflux pumps is prevalent in clinical Candida isolates. Potential efflux pump substrates (PEPSs), which are active against strains deficient in efflux pumps but inactive against wild-type strains, are usually missed in routine antifungal screening. Here we present a method for identification of PEPSs, and show that conjugation with mitochondria-targeting triphenylphosphonium cation (TPP⁺) can enhance or restore the compounds’ antifungal activity. The screening method involves co-culturing a wild-type C. albicans strain and a Cdr efflux pump-deficient strain, labelled with different fluorescent proteins. We identify several PEPSs from a library of natural terpenes, and restore their antifungal activity against wild-type and azole-resistant C. albicans by conjugation with TPP⁺. The most active conjugate (IS-2-Pi-TPP) kills C. albicans cells, prevents biofilm formation and eliminates preformed biofilms, without inducing significant resistance. The antifungal activity is accompanied by mitochondrial dysfunction and increased levels of intracellular reactive oxygen species. In addition, IS-2-Pi-TPP is effective against C. albicans in a mouse model of skin infection.