A Cationic Metal-Organic Framework to Scavenge Cell-Free DNA for Severe Sepsis Management.

Circulating cell-free DNA (cfDNA) released by damaged cells causes inflammation and has been associated with the progression of sepsis. One proposed strategy to treat sepsis is to scavenge this inflammatory circulating cfDNA. Here, we develop a cfDNA-scavenging nanoparticle (NP) that consists of cationic polyethylenimine (PEI) of different molecular weight grafted to zeolitic imidazolate framework-8 (PEI-g-ZIF) in a simple one-pot process. PEI-g-ZIF NPs fabricated using PEI 1800 and PEI 25k but not PEI 600 suppressed cfDNA-induced TLR activation and subsequent nuclear factor kappa B pathway activity. PEI 1800-g-ZIF NPs showed greater inhibition of cfDNA-associated inflammation and multiple organ injury than naked PEI 1800 (lacking ZIF), and had greater therapeutic efficacy in treating sepsis. These results indicate that PEI-g-ZIF NPs acts as a "nanotrap" that improves upon naked PEI in scavenging circulating cfDNA, reducing inflammation, and reversing the progression of sepsis, thus providing a novel strategy for sepsis treatment.

Research progress on antibacterial applications of metal-organic frameworks and their biomacromolecule composites.

With the extensive use of antibiotics, resulting in increasingly serious problems of bacterial resistance, antimicrobial therapy has become a global concern. Metal-organic frameworks (MOFs) are low-density porous coordination materials composed of metal ions and organic ligands, which can form composite materials with biomacromolecules such as proteins and polysaccharides. In recent years, MOFs and their derivatives have been widely used in the antibacterial field as efficient antibacterial agents. This review offers a detailed summary of the antibacterial applications of MOFs and their composites, and the different synthesis methods and antibacterial mechanisms of MOFs and MOF-based composites are briefly introduced. Finally, the challenges and prospects of MOFs-based antibacterial materials in the rapidly developing medical field were briefly discussed. We hope this review will provide new strategies for the medical application of MOFs-based antibacterial materials.

The Role of Tissue-Resident Macrophages in the Development and Treatment of Inflammatory Bowel Disease.

Inflammatory bowel disease (IBD), comprising Crohn's disease and ulcerative colitis, is a refractory disease with many immune abnormalities and pathologies in the gastrointestinal tract. Because macrophages can distinguish innocuous antigens from potential pathogens to maintain mucosa barrier functions, they are essential cells in the intestinal immune system. With numerous numbers in the intestinal tract, tissue-resident macrophages have a significant effect on the constant regeneration of intestinal epithelial cells and maintaining the immune homeostasis of the intestinal mucosa. They also have a significant influence on IBD through regulating pro-(M1) or anti-inflammatory (M2) phenotype polarization according to different environmental cues. The disequilibrium of the phenotypes and functions of macrophages, disturbed by intracellular or extracellular stimuli, influences the progression of disease. Further investigation of macrophages' role in the progression of IBD will facilitate deciphering the pathogenesis of disease and exploring novel targets to develop novel medications. In this review, we shed light on the origin and maintenance of intestinal macrophages, as well as the role of macrophages in the occurrence and development of IBD. In addition, we summarize the interaction between gut microbiota and intestinal macrophages, and the role of the macrophage-derived exosome. Furthermore, we discuss the molecular and cellular mechanisms participating in the polarization and functions of gut macrophages, the potential targeted strategies, and current clinical trials for IBD.

Metal-organic framework-mediated multifunctional nanoparticles for combined chemo-photothermal therapy and enhanced immunotherapy against colorectal cancer.

Because of molecular heterogeneity in tumors, clinical outcomes of tumor treatment are not very satisfactory, and novel strategies are therefore needed to address this challenge. Combination therapy could efficiently enhance tumor treatment by stimulating multiple pathways, reducing the systemic toxicity of monotherapy, and regulating the tumor immune microenvironments. Herein, metal-organic framework MIL-100 (Fe) nanoparticles (NPs) were synthesized by a microwave-assisted method, and oxaliplatin (OXA) and indocyanine green (ICG) were then loaded into hyaluronic acid (HA)-modified MIL-100 NPs to obtain multifunctional nanoparticles (OIMH NPs). The OIMH NPs exhibited sensitive photoacoustic imaging (PAI) for imaging-guided therapy and showed a good synergistic effect by combining chemotherapy with photothermal therapy (PTT) to kill tumor cells. Immunogenic cell death (ICD) and activation of T cells induced by the chemo-photothermal therapy could sensitize for immune checkpoint blockade (aPD-L1) response, thus eliciting systemic antitumor immunity. Finally, tumor inhibition was observed, which could be attributed to the combination of chemotherapy, PTT, and aPD-L1. On the basis of the study findings, an innovative imaging-mediated combined therapeutic strategy involving multifunctional NPs was proposed, which might potentially offer a new clinical treatment for colorectal cancer. STATEMENT OF SIGNIFICANCE: The metal-organic framework-mediated chemo-photothermal therapy guided by photoacoustic imaging (PAI) is an accurate and effective approach for tumor inhibition, which can synergistically achieve immunogenic cell death and lead to an increasing infiltration of immune cells in the tumor microenvironment, thereby enhancing the sensitivity for immune checkpoint blockade (aPD-L1) therapy. This type of therapy can not only reduce the systemic toxicity caused by traditional treatment methods, but it can also solve the issue of low response of immune checkpoint blockade in colorectal cancer (CRC). Our study provides experimental evidence for using the combination of immunotherapy and chemo-photothermal therapy against CRC.