Research progress on the application of retinal vascular bed area in diabetic retinopathy / 国际眼科杂志(Guoji Yanke Zazhi)

Retinal vascular bed area(RVBA)is the total area of retinal vasculature segmented by ultra-widefield fluorescein angiography(UWFA)images, and is an objective absolute value in square millimeter. RVBA is mainly affected by the diameter and length of retinal vessels, and whether RVBA increases or decreases depends on the “competition” between ischemia and angiogenesis, indicating subtle changes in retinal vascular morphology. As a new indicator for the study of retinal vascular diseases, RVBA may have higher stability and accuracy than the ischemia index(ISI)and non-perfusion area(NPA). RVBA is currently mainly used to evaluate the progression and prognosis of diabetic retinopathy(DR). It was found that retinal total RVBA in DR eyes was greater than the normal eyes and it decreased in DR eyes after anti-vascular endothelial growth factor(VEGF)treatment. These findings provide favorable support for the study of microvascular lesions in DR. In this article, the application of RVBA in DR was reviewed to provide a reference for the clinical study of RVBA in other retinal vascular diseases such as retinal vein occlusion(RVO).

Transcriptome Profiling of Light-Regulated Anthocyanin Biosynthesis in the Pericarp of Litchi.

Light is a key environmental factor that affects anthocyanin biosynthesis. To enhance our understanding of the mechanisms involved in light-regulated anthocyanin biosynthesis in the pericarp of litchi, we performed transcriptomic analyses on the basis of Illumina sequencing. Fruit clusters were bagged with double-layer Kraft paper bags at 42 days after anthesis. The bags were removed after 2 weeks. Under light conditions, anthocyanins accumulated rapidly in the pericarp. RNA sequences were de novo assembled into 75,935 unigenes with an average length of 913 bp. Approximately 74.5% of unigenes (56,601) were annotated against four public protein databases. A total of 16,622 unigenes that significantly differed in terms of abundance were identified. These unigenes are implicated in light signal perception and transduction, flavonoid biosynthesis, carotenoid biosynthesis, plant hormone signal transduction, and photosynthesis. In photoreceptors, the expression levels of UV RESISTANCE LOCUS 8 (UVR8), Phototropin 2 (PHOT2), Phytochrome B (PHYB), and Phytochrome C (PHYC) increased significantly when the fruits were exposed to light. This result indicated that they likely play important roles in anthocyanin biosynthesis regulation. After analyzed digital gene expression (DGE), we found that the light signal transduction elements of COP1 and COP10 might be responsible for anthocyanin biosynthesis regulation. After the bags were removed, nearly all structural and regulatory genes, such as UDP-glucose: flavonoid-3-O-glucosyltransferase (UFGT), MYB, basic helix-loop-helix (bHLH), and WD40, involved in the anthocyanin biosynthetic pathway were upregulated. In addition to MYB-bHLH-WD40 transcription complex, ELONGATED HYPOCOTYL (HY5), NAM/ATAF/CUC (NAC), homeodomain leucine zipper proteins (ATHBs), and FAR-RED ELONGATED HYPOCOTYL (FHY) possibly participate in light-induced responses. On the basis of DGEs and qRT-PCR validation, we observed a light-induced anthocyanin biosynthesis and regulation pattern in litchi pericarp. This study enhanced our understanding of the molecular mechanisms governing light-induced anthocyanin biosynthesis in litchi pericarp.

De novo assembly and characterization of pericarp transcriptome and identification of candidate genes mediating fruit cracking in Litchi chinensis Sonn.

Fruit cracking has long been a topic of great concern for growers and researchers of litchi (Litchi chinensis Sonn.). To understand the molecular mechanisms underlying fruit cracking, high-throughput RNA sequencing (RNA-Seq) was first used for de novo assembly and characterization of the transcriptome of cracking pericarp of litchi. Comparative transcriptomic analyses were performed on non-cracking and cracking fruits. A total of approximately 26 million and 29 million high quality reads were obtained from the two groups of samples, and were assembled into 46,641 unigenes with an average length of 993 bp. These unigenes can be useful resources for future molecular studies of the pericarp in litchi. Furthermore, four genes (LcAQP, 1; LcPIP, 1; LcNIP, 1; LcSIP, 1) involved in water transport, five genes (LcKS, 2; LcGA2ox, 2; LcGID1, 1) involved in GA metabolism, 21 genes (LcCYP707A, 2; LcGT, 9; Lcß-Glu, 6; LcPP2C, 2; LcABI1, 1; LcABI5, 1) involved in ABA metabolism, 13 genes (LcTPC, 1; Ca2+/H+ exchanger, 3; Ca2+-ATPase, 4; LcCDPK, 2; LcCBL, 3) involved in Ca transport and 24 genes (LcPG, 5; LcEG, 1; LcPE, 3; LcEXP, 5; Lcß-Gal, 9; LcXET, 1) involved in cell wall metabolism were identified as genes that are differentially expressed in cracked fruits compared to non-cracked fruits. Our results open new doors to further understand the molecular mechanisms behind fruit cracking in litchi and other fruits, especially Sapindaceae plants.

[Expression of T-bet and GATA3 in children with acute idiopathic thrombocytopenic purpura].

OBJECTIVE: To study the expression of transcriptional factors T-bet and GATA3 mRNA and the levels of IFN-gamma and IL-4 in blood in children with acute idiopathic thrombocytopenic purpura (ITP) and investigate the tendency of polarization of Th1/Th2 in children with ITP. METHODS: Blood T-bet and GATA3 mRNA expression were examined using RT-PCR and plasma IFN-gamma and IL-4 levels were measured using EIASA in children with acute ITP in acute (n=30) and remission stages (n=28). Twenty healthy children served as the controls. RESULTS: Blood T-bet mRNA expression and IFN-gamma levels in children with ITP in the acute stage were markedly higher than those in the remission stage and controls (p<0.01). In contrast, blood GATA3 mRNA expression and IL-4 levels in children with ITP in the acute stage were significantly lower than those in the remmission stage and controls (p<0.01). CONCLUSIONS: The high expression of T-bet and IFN-gamma and the low expression of GATA3 and IL-4 indicate the existence of Th1 polarization in children with acute ITP. This might be related to the regulation of T-bet and GATA3.