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Acute kidney injury (AKI) is a worldwide public health problem characterized by excessive inflammation with no specific therapy in clinic. Inflammation is not only a feature of AKI but also an essential promoter for kidney deterioration. Phosphoglycerate mutase 5 (PGAM5) was up-regulated and positively correlated with kidney dysfunction in human biopsy samples and mouse kidneys with AKI. PGAM5 knockout in mice significantly alleviated ischemia/reperfusion-induced kidney injury, mitochondrial abnormality and production of inflammatory cytokines. Elevated PGAM5 was found to be mainly located in kidney tubular epithelial cells and was also related to inflammatory response. Knockdown of PGAM5 inhibited the hypoxia/reoxygenation-induced cytosolic release of mitochondrial DNA (mtDNA) and binding of mtDNA with the cellular DNA receptor cGAS in cultured cells. cGAS deficiency also attenuated the inflammation and kidney injury in AKI. Mechanistically, as a protein phosphatase, PGAM5 was able to dephosphorylate the pro-apoptotic protein Bax and facilitate its translocation to mitochondrial membranes, and then initiate increased mitochondrial membrane permeability and release of mtDNA. Leaked mtDNA recognized by cGAS then initiated its downstream-coupled STING pathway, a component of the innate immune system that functions to detect the presence of cytosolic DNA. Thus, our results demonstrated mtDNA release induced by PGAM5-mediated Bax dephosphorylation and the activation of cGAS-STING pathway as critical determinants of inflammation and kidney injury. Hence, targeting this axis may be useful for treating AKI.

Maize (Zea mays) is one of the most important crops in the world. However, few agronomically important maize genes have been cloned and used for trait improvement, due to its complex genome and genetic architecture. Here, we integrated multiplexed CRISPR/Cas9-based high-throughput targeted mutagenesis with genetic mapping and genomic approaches to successfully target 743 candidate genes corresponding to traits relevant for agronomy and nutrition. After low-cost barcode-based deep sequencing, 412 edited sequences covering 118 genes were precisely identified from individuals showing clear phenotypic changes. The profiles of the associated gene-editing events were similar to those identified in human cell lines and consequently are predictable using an existing algorithm originally designed for human studies. We observed unexpected but frequent homology-directed repair through endogenous templates that was likely caused by spatial contact between distinct chromosomes. Based on the characterization and interpretation of gene function from several examples, we demonstrate that the integration of forward and reverse genetics via a targeted mutagenesis library promises rapid validation of important agronomic genes for crops with complex genomes. Beyond specific findings, this study also guides further optimization of high-throughput CRISPR experiments in plants.