A near-infrared fluorescent probe for tracking endogenous and exogenous H2O2 in cells and zebrafish.

H2O2 is an important signaling molecule in the body, and its levels fluctuate in many pathological sites, therefore, it can be used as a biomarker for early diagnosis of disease. Since the environment in vivo is extremely complex, it is of great significance to develop a probe that can accurately monitor the fluctuation of H2O2 level without interference from other physiological processes. Based on this, we designed and synthesized two new near-infrared H2O2 fluorescent probes, LTA and LTQ, based on the ICT mechanism. Both of them have good responses to H2O2, but LTA has a faster response speed. In addition, the probe LTA has good biocompatibility, good water solubility, and a large Stokes shift (95 nm). The detection limit is 4.525 µM. The probe was successfully used to visually detect H2O2 in living cells and zebrafish and was successfully used to monitor the changes in H2O2 levels in zebrafish due to APAP-induced liver injury.

Visualization of gene therapy with a liver cancer-targeted adeno-associated virus 3 vector.

Background: To evaluate the feasibility of a self-complementing recombinant adeno-associated virus 3 (scrAAV3) vector targeting liver cancer and non-invasively monitor gene therapy of liver cancer. Materials and methods: An scrAAV3-HSV1-TK-kallistatin (ATK) gene drug was constructed, which contained the herpes virus thymidine kinase (HSV1-TK) reporter gene and human endogenous angiogenesis inhibitor (kallistatin) gene for non-invasive imaging of gene expression. Subcutaneous xenografted tumors of hepatoma in nude mice were generated for positron emission tomography/computed tomography (PET/CT) imaging. The ATK group was injected with the ATK gene through the tail vein, and an imaging agent was injected 2 weeks later. PET/CT imaging was performed at 1 hour after injection of the imaging agent. The control group was injected with phosphate-buffered saline at the same volume as the ATK gene drug. HE staining is used for pathological observation of tumor sections. HSV1-TK and kallistatin expression was identified by immunofluorescence, real-time quantitative PCR, and western blotting. Results: Radioactivity on PET/CT images was significantly higher in the ATK group compared with the control group. 18F-FHBG uptake values of left forelegs in ATK and control groups were 0.591±0.151% and 0.017 ± 0.011% ID/g (n=5), respectively (P<0.05). After injection of the ATK gene drug, mRNA and protein expression of HSV1-TK and kallistatin in subcutaneous xenograft tumors was detected successfully. In vitro analysis demonstrated significant differences in the expression of HSV1-TK and kallistatin between ATK and control groups (P<0.05). Conclusions: The scrAAV3 vector has a strong liver cancer-targeting ability, and the ATK gene drug can be used for targeted and non-invasive monitoring of liver cancer gene therapy.