Although cancer immunotherapy has made great strides in the clinic, it is still hindered by the tumor immunosuppressive microenvironment (TIME). The stimulator of interferon genes (STING) pathway which can modulate TIME effectively has emerged as a promising therapeutic recently. However, the delivery of most STING agonists, specifically cyclic dinucleotides (CDNs), is performed intratumorally due to their insufficient pharmacological properties, such as weak permeability across cell membranes and vulnerability to nuclease degradation. To expand the clinical applicability of CDNs, a novel pH-sensitive polycationic polymer-modified lipid nanoparticle (LNP-B) system was developed for intravenous delivery of CDNs. LNP-B significantly extended the circulation of CDNs and enhanced the accumulation of CDNs within the tumor, spleen, and tumor-draining lymph nodes compared with free CDNs thereby triggering the STING pathway of dendritic cells and repolarizing pro-tumor macrophages. These events subsequently gave rise to potent anti-tumor immune reactions and substantial inhibition of tumors in CT26 colon cancer-bearing mouse models. In addition, due to the acid-sensitive property of the polycationic polymer, the delivery system of LNP-B was more biocompatible and safer compared with lipid nanoparticles formulated with an indissociable cationic DOTAP (LNP-D). These findings suggest that LNP-B has great potential in the intravenous delivery of CDNs for tumor immunotherapy.

Cold tumors have a poor response to tumor immunotherapy due to low immune cell infiltration and the ability to evade immune attacks. Converting cold tumors into hot tumors can enhance the clinical effectiveness of anti-tumor immunotherapy. High-intensity focused ultrasound (HIFU) as a non-invasive treatment can damage tumors through mechanical effects, but there is a lack of research on its cytotoxic mechanisms at the cellular level and its role in inducing anti-immune responses. In this study, the role of HIFU in triggering tumor ferroptosis by disrupting the GSH/GSSG balance through mechanochemical action and the associated anti-tumor immune priming effect were investigated. The use of a nano-enhancer loaded with PFOB combined with HIFU could enhance ferroptosis in triple-negative breast cancer at a specific stage of tumor growth (UTGR = 0) while promoting the conversion of a cold tumor into a hot tumor, thereby improving the immune response. Overall, this provides valuable guidance for the clinical application of HIFU in tumor immunotherapy.

Chronic inflammation is critical in the onset and progression of atherosclerosis (AS). The lipopolysaccharide (LPS) level in the circulation system is elevated in AS patients and animal models, which is correlated with the severity of AS. Inspired by the underlying mechanism that LPS could drive the polarization of macrophages toward the M1 phenotype, aggravate inflammation, and ultimately contribute to the exacerbation of AS, LPS in the circulation system was supposed to be the therapeutic target for AS treatment. In the present study, polymyxin (PMB) covalently conjugated to PEGylated liposomes (PLPs) were formulated to adsorb LPS through specific interactions between PMB and LPS. In vitro, the experiments demonstrated that PLPs could adsorb LPS, reduce the polarization of macrophages to M1 phenotype and inhibit the formation of foam cells. In vivo, the study revealed that PLPs treatment reduced the serum levels of LPS and pro-inflammatory cytokines, decreased the proportion of M1-type macrophages in AS plaque, stabilized AS plaque, and downsized the plaque burdens in arteries, which eventually attenuated the progression of AS. Our study highlighted LPS in the circulation system as the therapeutic target for AS and provided an alternative strategy for AS treatment.

The promise of regeneration therapy for restoration of damaged myocardium after cardiac ischemic injury relies on targeted delivery of proliferative molecules into cardiomyocytes whose healing benefits are still limited owing to severe immune microenvironment due to local high concentration of proinflammatory cytokines. Optimal therapeutic strategies are therefore in urgent need to both modulate local immunity and deliver proliferative molecules. Here, we addressed this unmet need by developing neutrophil-mimic nanoparticles NM@miR, fabricated by coating hybrid neutrophil membranes with artificial lipids onto mesoporous silica nanoparticles (MSNs) loaded with microRNA-10b. The hybrid membrane could endow nanoparticles with strong capacity to migrate into inflammatory sites and neutralize proinflammatory cytokines and increase the delivery efficiency of microRNA-10b into adult mammalian cardiomyocytes (CMs) by fusing with cell membranes and leading to the release of MSNs-miR into cytosol. Upon NM@miR administration, this nanoparticle could home to the injured myocardium, restore the local immunity, and efficiently deliver microRNA-10b to cardiomyocytes, which could reduce the activation of Hippo-YAP pathway mediated by excessive cytokines and exert the best proliferative effect of miR-10b. This combination therapy could finally improve cardiac function and mitigate ventricular remodeling. Consequently, this work offers a combination strategy of immunity modulation and proliferative molecule delivery to boost cardiac regeneration after injury.

Platelets buoy up cancer metastasis via arresting cancer cells, enhancing their adhesion, and facilitating their extravasation through the vasculature. When deprived of intracellular and granular contents, platelet decoys could prevent metastatic tumor formation. Inspired by these, we developed nanoplatesomes by fusing platelet membranes with lipid membranes (P-Lipo) to restrain metastatic tumor formation more efficiently. It was shown nanoplateletsomes bound with circulating tumor cells (CTC) efficiently, interfered with CTC arrest by vessel endothelial cells, CTC extravasation through endothelial layers, and epithelial-mesenchymal transition of tumor cells as nanodecoys. More importantly, in the mouse breast tumor metastasis model, nanoplateletsomes could decrease CTC survival in the blood and counteract metastatic tumor growth efficiently by inhibiting the inflammation and suppressing CTC escape. Therefore, nanoplatelesomes might usher in a new avenue to suppress lung metastasis.

Anti-virulence strategy has been considered as one of the most promising approaches to combat drug-resistant bacterial infections. Pore-forming toxins (PFTs) are the largest class of bacterial toxins, inflicting their virulence effect through creating pores on the cell membrane. However, current solutions for eliminating PFTs are mostly designed based on their molecular structure, requiring customized design for different interactions. In the present study, we employed erythroliposome (denoted as RM-PL), a biomimetic platform constructed by artificial lipid membranes and natural erythrocyte membranes, to neutralize different hemolytic PFTs regardless of their molecular structure. When tested with model PFTs, including α-hemolysin, listeriolysin O, and streptolysin O, RM-PL could completely inhibit toxin-induced hemolysis in a concentration-dependent manner. In vivo studies further confirmed that RM-PL could efficiently neutralize various toxins and save animals' lives without causing damage to organs or tissues. In addition, we explored the underlying mechanisms of this efficient detoxification ability and found that it was mainly macrophages in the spleen and the liver that took up RM-PL-absorbed toxins through a variety of endocytosis pathways and digested them in lysosomes. In summary, the biomimetic RM-PL presented a promising system for broad-spectrum and powerful toxin neutralization with a mechanism of lysosome-mediated toxin degradation.

Tumor-targeted immunotherapy is a remarkable breakthrough, offering the inimitable advantage of specific tumoricidal effects with reduced immune-associated cytotoxicity. However, existing platforms suffer from low efficacy, inability to induce strong immunogenic cell death (ICD), and restrained capacity of transforming immune-deserted tumors into immune-cultivated ones. Here, an innovative platform, perfluorooctyl bromide (PFOB) nanoemulsions holding MnO₂ nanoparticles (MBP), was developed to orchestrate cancer immunotherapy, serving as a theranostic nanoagent for MRI/CT dual-modality imaging and advanced ICD. By simultaneously depleting the GSH and eliciting the ICD effect via high-intensity focused ultrasound (HIFU) therapy, the MBP nanomedicine can regulate the tumor immune microenvironment by inducing maturation of dendritic cells (DCs) and facilitating the activation of CD8⁺ and CD4⁺ T cells. The synergistic GSH depletion and HIFU ablation also amplify the inhibition of tumor growth and lung metastasis. Together, these findings inaugurate a new strategy of tumor-targeted immunotherapy, realizing a novel therapeutics paradigm with great clinical significance.

Cancer immunotherapy has veered the paradigm of cancer treatment. Despite recent advances in immunotherapy for improved antitumor efficacy, the complicated tumor microenvironment (TME) is highly immunosuppressive, yielding both astounding and unsatisfactory clinical successes. In this regard, clinical outcomes of currently available immunotherapy are confined to the varied immune systems owing in large part to the lack of understanding of the complexity and diversity of the immune context of the TME. Various advanced designs of nanomedicines could still not fully surmount the delivery barriers of the TME. The immunosuppressive TME may even dampen the efficacy of antitumor immunity. Recently, some nanotechnology-related strategies have been inaugurated to modulate the immunosuppressive cells within the tumor immune microenvironment (TIME) for robust immunotherapeutic responses. In this review, we will highlight the current understanding of the immunosuppressive TIME and identify disparate subclasses of TIME that possess an impact on immunotherapy, especially those unique classes associated with the immunosuppressive effect. The immunoregulatory cell types inside the immunosuppressive TIME will be delineated along with the existing and potential approaches for immunosuppressive cell modulation. After introducing the various strategies, we will ultimately outline both the novel therapeutic targets and the potential issues that affect the efficacy of TIME-based nanomedicines.