CQ induces vacuole formation and cell death in ARPE-19 cells. Initially, vacuoles developed from enlarged lysosomes, followed by the activation of upstream steps in the autophagy pathway and the formation of LC3-positive AVs. Because CQ blocked the fusion of AVs with lysosomes, autophagic protein degradation was inhibited, indicating that CQ-induced retinotoxicity may be caused by the accumulation of potentially toxic ubiquitinated proteins.

The TB incidence rate and mortality rate in the Republic of Korea are 77 and 5.2 per 100,000 people respectively (2016), which are the highest among the Organization for Economic Co-operation and Development countries. Recently, the Republic of Korea's TB incidence decreased dramatically among people in their teens and twenties. This is largely attributed to the contact investigation efforts in targeting schools over the past few years. However, the TB incidence in the elderly still remains high and is even increasing compared to the past 10 years. Older persons account for 42% of all TB cases and 82% of deaths due to TB. On the other hand, the Republic of Korea's TB treatment success rate has gradually increased due to various programs, such as Control of noncompliance, insurance coverage for TB diagnosis and treatment, and TB public-private mix models. This study suggests that policy makers should focus their efforts on the policies with priorities to achieve a significant reduction in TB incidence based on the 2nd National Strategic Plan for Tuberculosis Control (2018-2022).

We have recently demonstrated that the accumulation of labile zinc in lysosomes during oxidative stress causes lysosomal membrane permeabilization (LMP) in cultured hippocampal neurons. Since autophagy involves fusion of autophagic vacuoles (AVs) with lysosomes, zinc accumulation may start in AVs. In the present study, we examined the role of endogenous zinc in H2O2-induced autophagy and cell death in mouse astrocyte cultures. Live-cell confocal imaging of astrocytes transfected with GFP-LC3 revealed that the number of AVs positive for LC3 (microtubule-associated protein 1 light chain 3) increased following exposure to H2O2 or ferrous chloride (FeCl2). Staining of RFP-LC3-transfected astrocytes with FluoZin-3 indicated that the levels of labile zinc increased in AVs as well as in the cytosol and nuclei. The majority of AVs were double-stained with LysoTracker, indicating that they were fused with lysosomes. Chelation of zinc with tetrakis [2-pyridylmethyl]ethylenediamine (TPEN) decreased the number of AVs in H2O2-treated astrocytes, whereas exposure to zinc increased their number, suggesting that dysregulation of zinc homeostasis is mechanistically linked to autophagy. Unexpectedly, inhibition of autophagy blocked the rise in labile zinc levels. Astrocytic death induced by H2O2) was ccompanied by LMP. Autophagy inhibitors (3-methyladenine, bafilomycin-1) or TPEN attenuated LMP and cell death in astrocytes. These results support the possibility that endogenous zinc plays a key role in autophagy under oxidative stress in astrocytes, and suggest that autophagy is a necessary preceding event for LMP and cell death in oxidative injury.

In this study, we describe a novel approach to human cancer therapy that is based upon trans-splicing ribozyme-mediated replacement of cancer-specific RNAs with new transcripts that exert therapeutic activities. We have developed a specific ribozyme that can reprogram human telomerase reverse transcriptase (hTERT) RNA to induce transgene activity selectively in cancer cells that express the RNA. The ribozyme-mediated triggering of the transgene expression was accomplished via a high-fidelity trans-splicing reaction with the targeted residue in the hTERT-expressing cells. The ribozyme also induced cytotoxic activity in various hTERT-expressing cancer cells, hence selectively retarding the growth of those cells. Efficient and specific cell regression was also detected with ganciclovir (GCV) treatment only in hTERT-positive cancer cells, which were established to express stably the specific ribozyme that contains the herpes simplex virus thymidine kinase (HSV-tk) gene. Tissue-specific expression of the ribozyme could further augment the target specificity of the ribozyme. Importantly, we observed efficient regression of tumors with GCV treatment in mice that had been inoculated subcutaneously with hTERT-positive cancer cells that stably expressed the specific ribozyme that contains HSV-tk. These results suggest that the hTERT RNA-targeting trans-splicing ribozyme could be a powerful agent for tumor-targeted specific gene therapy.