Ferroptosis was involved in the oleic acid-induced acute lung injury in mice.

The aim of the present study was to investigate the role of ferroptosis in acute lung injury (ALI) mouse model induced by oleic acid (OA). ALI was induced in the mice via the lateral tail vein injection of pure OA. The histopathological score of lung, lung wet-dry weight ratio and the protein content of bronchoalveolar lavage fluid (BALF) were used as the evaluation indexes of ALI. Iron concentration, glutathione (GSH) and malondialdehyde (MDA) contents in the lung tissues were measured using corresponding assay kits. The ultrastructure of pulmonary cells was observed by transmission electron microscope (TEM), and the expression level of prostaglandin-endoperoxide synthase 2 (PTGS2) mRNA was detected by quantitative polymerase chain reaction (q-PCR). Protein expression levels of glutathione peroxidase 4 (GPX4), ferritin and transferrin receptor 1 (TfR1) in lung tissues were determined by Western blot. The results showed that histopathological scores of lung tissues, lung wet-dry weight ratio and protein in BALF in the OA group were higher than those of the control group. In the OA group, the mitochondria of pulmonary cells were shrunken, and the mitochondrial membrane was ruptured. The expression level of PTGS2 mRNA in the OA group was seven folds over that in the control group. Iron overload, GSH depletion and accumulation of MDA were observed in the OA group. Compared with the control group, the protein expression levels of GPX4 and ferritin in lung tissue were down-regulated in the OA group. These results suggest that ferroptosis plays a potential role in the pathogenesis of ALI in our mouse model, which may provide new insights for development of new drugs for ALI.

MARIS plays important roles in Arabidopsis pollen tube and root hair growth.

In flowering plants, male gametes are delivered to female gametes for double fertilization through pollen tubes. Therefore, pollen tube growth is crucial for double fertilization. Despite its importance to sexual reproduction, genetic mechanisms of pollen tube growth remain poorly understood. In this study, we characterized the receptor-like cytoplasmic protein kinase (RLCK) gene, MARIS (MRI) that plays critical roles in pollen tube growth. MRI is preferentially expressed in pollen grains, pollen tubes and roots. Mutation in MRI by a Ds insertion led to a burst of pollen tubes after pollen germination. Pollen-rescue assay by pollen and pollen tube-specific expression of MRI in the mri-4 mutant showed that loss of MRI function also severely affected root hair elongation. MRI protein interacted with the protein kinase OXIDATIVE SIGNAL INDUCIBLE1 (OXI1) in the in vitro and in vivo assays, which functions in plant defence and root hair development, and was phosphorylated by OXI1 in vitro. Our results suggest that MRI plays important roles in pollen tube growth and may function in root hair elongation through interaction with OXI1.

ABORTED GAMETOPHYTE 1 is required for gametogenesis in Arabidopsis.

In flowering plants, the male and female gametogenesis is a crucial step of sexual reproduction. Although many genes have been identified as being involved in the gametogenesis process, the genetic mechanisms underlying gametogenesis remains poorly understood. We reported here characterization of the gene, ABORTED GAMETOPHYTE 1 (AOG1) that is newly identified as essential for gametogenesis in Arabidopsis thaliana. AOG1 is expressed predominantly in reproductive tissues including the developing pollen grains and ovules. The AOG1 protein shares no significant amino acid sequence similarity with other documented proteins and is located mainly in nuclei of the cells. Mutation in AOG1 caused degeneration of pollen at the uninucleate microspore stage and severe defect in embryo sacs, leading to a significant reduction in male and female fertility. Furthermore, the molecular analyses showed that the aog1 mutant significantly affected the expression of several genes, which are required for gametogenesis. Our results suggest that AOG1 plays important roles in gametogenesis at the stage prior to pollen mitosis I (PMI) in Arabidopsis, possibly through collaboration with other genes.