SummaryNeovascularization (NV), as a cardinal complication of several ocular diseases, has been intensively studied, and research has shown its close association with inflammation and immune cells. In the present study, the role of interleukin-17A (IL-17A) in angiogenesis in the process of ocular NV both in vivo and in vitro was investigated. Also, a paracrine role of IL-17A was demonstrated in the crosstalk between endothelial cells and macrophages in angiogenesis. In the retinas of mice with retinopathy of prematurity, the IL-17A expression increased significantly at postnatal day 15 (P15) and P18 during retinal NV. Mice given IL-17A neutralizing antibody (NAb) developed significantly reduced choroidal NV and retinal NV. Studies on vascular endothelial growth factor (VEGF) over-expressing mice suggested that IL-17A modulated NV through the VEGF pathway. Furthermore, IL-17A deficiency shifted macrophage polarization toward an M2 phenotype during retinal NV with significantly reduced M1 cytokine expression compared with wild-type controls. In vitro assays revealed that IL-17A treated macrophage supernatant gave rise to elevated human umbilical vascular endothelial cell proliferation, tube formation and VEGF receptor 1 and receptor 2 expression. Therefore, IL-17A could potentially serve as a novel target for treating ocular NV diseases. The limitation of this study involved the potential mechanisms, such as which transcription accounted for macrophage polarization and how the subsequent cytokines were modulated when macrophages were polarized. Further studies need to be undertaken to definitively determine the extent to which IL-17A neutralizing anti-angiogenic activity depends on macrophage modulation compared with anti-VEGF treatment.

The aim of the present study was to characterize the phenotypic shift, quantity and role changes in different subgroups of retinal macrophages in a mouse model of oxygen-induced retinopathy (OIR). The mRNA expression levels of macrophage M1 and M2 subgroup marker genes and polarization-associated genes were analyzed by RT-qPCR. The number of M1 and M2 macrophages in our mouse model of OIR was analyzed by flow cytometry at different time points during the progression of OIR. Immunofluorescence whole mount staining of the retinas of mice with OIR was performed at different time points to examine the influx of macrophages, as well as the morphological characteristics and roles of M1 and M2 macrophages. An increased number of macrophages was recruited during the progression of angiogenesis in the retinas of mice with OIR due to the pro-inflammatory microenvironment containing high levels of cell adhesion and leukocyte transendothelial migration molecules. RT-qPCR and flow cytometric analysis at different time points revealed a decline in the number of M1 cells from a significantly high level at post-natal day (P)13 to a relatively normal level at P21, as well as an increase in the number of M2 cells from P13 to P21 in the mice with OIR, implicating a shift of macrophage polarization towards the M2 subtype. Immunofluorescence staining suggested that the M1 cells interacted with endothelial tip cells at the vascular front, while M2 cells embraced the emerging vessels and bridged the neighboring vessel sprouts. Thus, our data indicate that macrophages play an active role in OIR by contributing to the different steps of neovascularization. Our findings indicate that tissue macrophages may be considered as a potential target for the anti-angiogenic therapy of ocular neovascularization disease.

Fleshy fruits are major sources of necessary nutrients in many diets worldwide. Most fruit quality attributes emerge during ripening making the fruit more attractive to consumers. Understanding the molecular regulatory network underpinning fleshy fruit ripening is important not only for fruit quality improvement but also for postharvest shelf life. The phytohormone ethylene plays an essential role in climacteric fruit ripening and a number of studies have demonstrated that ethylene signaling components and related transcription factors are involved in the regulation of fruit ripening. However, the transcriptional network by which ethylene interacts with other signaling pathways to regulate the ripening process is not fully understood. In this review, focusing on the tomato as a reference species, the key points regarding the role of ethylene in coordinating the ripening process at the molecular and physiological levels are described. The interplay between ethylene and ripening‐related regulators and its crosstalk with other phytohormones and present recent data on ripening‐related epigenetic modifications are also discussed. Overall, the paper summarizes the most advanced research progress in this area to help facilitate its future development.

Tomato is a model for studying the climate for fruit development and ripening. Down-regulation of a tomato bell-like homeodomain 4 (SlBL4) resulted in a slightly darker green fruit phenotype and increased accumulation of starch, fructose and glucose. Chlorophyll content analysis and TEM observation confirmed these phenotypes, indicating that SlBL4 was involved in the chlorophyll accumulation and chloroplast formation in tomato. SlBL4-i fruits had noticeably decreased firmness and have larger intercellular spaces and thinner cell walls in the ripened fruits. RNA-Seq had identified differential expression genes involved in chlorophyll metabolism, chloroplast development, cell wall metabolism and carotenoid metabolism. ChIP-seq identified (G/A) GCCCA (A/T/C) and (C/A/T) (C/A/T) AAAAA (G/A/T) (G/A) motifs. SlBL4 directly inhibited protoporphyrinogen oxidase (SlPPO), magnesium chelatase H subunit (SlCHLD), pectinesterase (SlPE) protochlorophyllide reductase (SlPOR), chlorophyll a/b binding protein (SlCAB-3B) and homeobox protein knotted 2 (TKN2) and expressions. In addition, SlBL4 positively regulated squamosa promoter binding protein-like colorless non-ripening (LeSPL-CNR) expression. Our study indicated that SlBL4 was involved in the chlorophyll accumulation, chloroplast development, cell wall metabolism and carotenoids accumulation during tomato fruit ripening. Our data reveal novel evidence for the transcriptional regulation mechanism of BELL mediated fruit growth and ripening.