The oxidation resistance gene 1 (OXR1) prevents oxidative stress-induced cell death by an unknown pathway. Here, depletion of human OXR1 (hOXR1) sensitized several human cell lines to hydrogen peroxide-induced oxidative stress, reduced mtDNA integrity, and increased apoptosis. In contrast, depletion of hOXR1 in cells lacking mtDNA showed no significant change in ROS or viability, suggesting that OXR1 prevents intracellular hydrogen peroxide-induced increase in oxidative stress levels to avoid a vicious cycle of increased oxidative mtDNA damage and ROS formation. Furthermore, expression of p21 and the antioxidant genes GPX2 and HO-1 was reduced in hOXR1-depleted cells. In sum, these data reveal that human OXR1 upregulates the expression of antioxidant genes via the p21 signaling pathway to suppress hydrogen peroxide-induced oxidative stress and maintain mtDNA integrity.

The oxidation resistance gene 1 (OXR1) is crucial for protecting against oxidative stress; however, its molecular function is unknown. We employed RNA sequencing to examine the role of human OXR1 for genome wide transcription regulation. In total, in non-treated and hydrogen peroxide exposed HeLa cells, OXR1 depletion resulted in down-regulation of 554 genes and up-regulation of 253 genes. These differentially expressed genes include transcription factors (i.e. HIF1A, SP6, E2F8 and TCF3), antioxidant genes (PRDX4, PTGS1 and CYGB) and numerous genes of the p53 signaling pathway involved in cell-cycle arrest (i.e. cyclin D, CDK6 and RPRM) and apoptosis (i.e. CytC and CASP9). We demonstrated that OXR1 depleted cells undergo cell cycle arrest in G2/M phase during oxidative stress and increase protein expression of the apoptosis initiator protease CASP9. In summary, OXR1 may act as a sensor of cellular oxidative stress to regulate the transcriptional networks required to detoxify reactive oxygen species and modulate cell cycle and apoptosis.

As hot topics in the chemical conversion of CO2, the photo‐/electrocatalytic reduction of CO2 and use of CO2 as a supporter for energy storage have shown great potential for the utilization of CO2. However, many obstacles still exist on the road to realizing highly efficient chemical CO2 conversion, such as inefficient uptake/activation of CO2 and mass transport in catalysts. Covalent organic frameworks (COFs), as a kind of porous material, have been widely explored as catalysts for the chemical conversion of CO2 owing to their unique features. In particular, COF‐based functional materials containing diverse active sites (such as single metal sites, metal nanoparticles, and metal oxides) offer great potential for realizing CO2 conversion and energy storage. This Minireview discusses recent breakthroughs in the basic knowledge, mechanisms, and pathways of chemical CO2 conversion strategies that use COF‐based functional catalysts. In addition, the challenges and prospects of COF‐based functional catalysts for the efficient utilization of CO2 are also introduced.