The design and synthesis of near-infrared (NIR) emissive fluorophores for the imaging of organelles and photodynamic therapy have received enormous attention. Hence, the development of NIR emissive fluorophores for high-fidelity lysosome targeting, two-photon fluorescence imaging, and the inducing of photo-triggered cancer-cell apoptosis is highly desirable. In this study, a novel lysosome-targeting two-photon fluorescent photosensitizer (TTRh-CN) is prepared and comprehensively investigated. TTRh-CN demonstrates near-infrared (NIR) emission, good biocompatibility, and superior photostability, and it can act as a two-photon fluorescent agent for the clear visualization of living cells and the vascular system within tissue, with deep-tissue penetration abilities. Furthermore, TTRh-CN can efficiently produce ROS in conjunction with lysosomes in situ upon light irradiation, which can damage lysosomes, up-regulate LC3 and Beclin1, increase BAX release, and induce cell apoptosis. The efficacy of TTRh-CN as a photosensitizer is explored in vivo. All these results confirm that TTRh-CN can serve as a potential platform for the two-photon fluorescence imaging of cells/tissue and for organelle-specific photodynamic therapy.

Background: It is now understood that HBV can induce innate and adaptive immune response disorders by affecting immunosuppressive macrophages, resulting in chronic HBV infection. However, the underlying mechanism is not fully understood. Dysregulated protein acetylation can reportedly influence the differentiation and functions of innate immune cells by coordinating metabolic signaling. This study aims to assess whether HBV suppresses macrophage-mediated innate immune responses by affecting protein acetylation and to elucidate the underlying mechanisms of HBV immune escape. Methods: We investigated the effect of HBV on the acetylation levels of human THP-1 macrophages and identified potential targets of acetylation that play a role in glucose metabolism. Metabolic and immune phenotypes of macrophages were analyzed using metabolomic and flow cytometry techniques. Western blot, immunoprecipitation, and immunofluorescence were performed to measure the interactions between deacetylase and acetylated targets. Chronic HBV persistent infected mice were established to evaluate the role of activating the tricarboxylic acid (TCA) cycle in macrophages for HBV clearance. Results: Citrate synthase/pyruvate dehydrogenase complex hyperacetylation in macrophages after HBV stimulation inhibited their enzymatic activities and was associated with impaired TCA cycle and M2-like polarization. HBV downregulated Sirtuin 3 (SIRT3) expression in macrophages by means of the toll-like receptor 2 (TLR2)-NF-κB- peroxisome proliferatoractivated receptor γ coactivator 1α (PGC-1α) axis, resulting in citrate synthase/pyruvate dehydrogenase complex hyperacetylation. In vivo administration of the TCA cycle agonist dichloroacetate inhibited macrophage M2-like polarization and effectively reduced the number of serum HBV DNA copies. Conclusions: HBV-induced citrate synthase/pyruvate dehydrogenase complex hyperacetylation negatively modulates the innate immune response by impairing the TCA cycle of macrophages. This mechanism represents a potential therapeutic target for controlling HBV infection.

An innovative strategy to transarterial infusion photothermal therapy (TAIPPT) of VX2 tumor implanted in rabbit is reported.

Lysosomes is emerging as a promising therapeutic target for improving immunotherapy, which dysfunction would trigger lysosomal membrane permeabilization increase and subsequent leakage of reduced iron, which contributed to ferroptosis through cell-intrinsic Fenton chemistry. However, the integrity of lysosomal membranes is not susceptible to disrupt, owing to the presence of several Endo-lysosomal damage-response mechanisms. Herein, we developed a lysosome-targeted photosensitizer (TLA), which possessed robust light stability, good bio-compatibility, and high photodynamic therapy (PDT) effect. Upon internalized by cancer cells, TLA was specifically accumulated in lysosome, and which would destroy the integrity of lysosomal membranes and inhibit protective autophagy upon exposure to light irradiation. Subsequently, the cancer cells were suffered from ferroptosis through triggering cell-intrinsic Fenton chemistry and mitochondrial dysfunction, which would release damage-associated molecular pattern molecules (DAMPs) to induce immunogenic cell death and remodel immunosuppressive tumor microenvironment. Notably, combined with PD-L1 antibody and TLA could greatly potentiate the immune response and exhibit highest anti-tumor effects. In summary, this novel lysosome-targeted photosensitizer could serve as a promising strategy for the treatment of colorectal cancer.

Introduction: It will be challenging to develop high-performance organic chromophores for light-triggered thermal ablation of the tumor. Besides, the mechanisms of organic chromophores for tumor therapy remain unclear. Herein, an acceptor-π-donor (A-π-D) structured organic chromophore based on 2-dicyanomethylenethiazole named PTM was developed for photothermal therapy (PTT) of tumors. Methods and Results: Biocompatible PTM nanoparticles (PTM NPs) were fabricated by enclosing PTM with Pluronic F-127. The results of optical and photothermal properties of PTM NPs showed robust near-infrared (NIR) absorption, excellent photostability and high photothermal conversion efficiency (56.9%). The results of flow cytometry, fluorescence microscopy, apoptosis, CCK-8 assays and animal experiments showed that PTM NPs had a good killing effect on tumors under NIR laser irradiation. Furthermore, mechanistic studies, RNA-seq and biological analysis revealed that PTM NPs can cause tumor cell death via DNA damage-mediated apoptosis. Conclusion: Light-induced thermal ablation effects of PTM NPs in vitro and vivo were surveyed. Collectively, our studies provided a new approach to developing a safe and effective photothermal agent for cancer treatment.