NAC transcription factor SlNOR-like1 plays a dual regulatory role in tomato fruit cuticle formation.

The plant cuticle is an important protective barrier on the plant surface, constructed mainly by polymerized cutin matrix and a complex wax mixture. Although the pathway of plant cuticle biosynthesis has been clarified, knowledge of the transcriptional regulation network underlying fruit cuticle formation remains limited. In the present work, we discovered that tomato fruits of the NAC transcription factor SlNOR-like1 knockout mutants (nor-like1) produced by CRISPR/Cas9 [clustered regularly interspaced short palindromic repeats (CRISPR)/CRISPR-associated protein 9] displayed reduced cutin deposition and cuticle thickness, with a microcracking phenotype, while wax accumulation was promoted. Further research revealed that SlNOR-like1 promotes cutin deposition by binding to the promoters of glycerol-3-phosphate acyltransferase6 (SlGPAT6; a key gene for cutin monomer formation) and CUTIN DEFICIENT2 (SlCD2; a positive regulator of cutin production) to activate their expression. Meanwhile, SlNOR-like1 inhibits wax accumulation, acting as a transcriptional repressor by targeting wax biosynthesis, and transport-related genes 3-ketoacyl-CoA synthase1 (SlKCS1), ECERIFERUM 1-2 (SlCER1-2), SlWAX2, and glycosylphosphatidylinositol-anchored lipid transfer protein 1-like (SlLTPG1-like). In conclusion, SlNOR-like1 executes a dual regulatory effect on tomato fruit cuticle development. Our results provide a new model for the transcriptional regulation of fruit cuticle formation.

[Effects of MD2 gene silencing on high glucose-induced proliferation inhibition, apoptosis and inflammation in rat cardiomyocytes].

OBJECTIVE: To investigate the effects of myeloid differentiation-2 (MD2) gene silencing on high glucose-induced proliferation inhibition, apoptosis and inflammation in rat cardiomyocytes. METHODS: The immortalized rat cardiomyocyte cell line H9C2 were transfected with MD2 small interfering RNA (si-MD2) and negative control for 24 h, then stimulated with high glucose (HG) for 48 h. RT-qPCR was performed to detect the mRNA levels of MD2 and inflammatory factors TNF-α, IL-1ß and IL-6. MTS and flow cytometry were used to evaluate cell proliferation, cell cycle and apoptosis rate. Western blot was used to detect protein expression levels and phosphorylation levels. RESULTS: The mRNA and protein levels of MD2 in H9C2 cells were dramatically decreased after transfected with si-MD2 (P＜0.01). After stimulation of high glucose, the mRNA levels of inflammatory factors, the cells in G0/G1 phase , the cell apoptosis rate and the protein level of cleaved Caspase-3 were significantly increased, while the cell proliferation ability was decreased (P＜0.01). MD2 gene silencing antagonized the effects of high glucose on cell proliferation, cell cycle, cell apoptosis and the mRNA levels of TNF-α, IL-1ß , IL-6(P＜0.05). Western blot analysis showed that the phosphorylation levels of extracellular signal-regulated kinase(ERK1/2), P38 mitogen-activated protein kinase(P38 MAPK) and C-Jun N-terminal kinase(JNK) protein were increased significantly in H9C2 cells treated with high glucose, which could be reversed by silencing of MD2 (P＜0.01). CONCLUSION: This study demonstrates that MD2 gene silencing reverses high glucose-induced myocardial inflammation, apoptosis and proliferation inhibition via the mechanisms involving suppression of ERK, P38 MAPK, JNK signaling pathway.

[Protective effects of Curcumin analogue L6H4 on kidney from type 2 diabetic rats].

OBJECTIVE: To investigate the protective effect of curcumin analogue L6H4 on the kidney from the type 2 diabetic rats. METHODS: Twenty-four SPF male SD rats were randomly divided into 3 groups(n=8):normal control group(NC),diabetes mellitus group(DM) and DM+L6H4-treatment group(DT). After rats were fed with high-fat diet for 4 weeks, both the DM and DT groups were injected with streptozotocin intraperitoneally to induce type 2 diabetes mellitus models. The rats in DT group were given L6H4 by gavage at the dose of 0.2 mg/kg·d for 8 weeks. After the treatment, the 24 h urinary protein, fasting blood glucose (FBG), triglyceride (TG), serum creatinine(Scr),blood urea nitrogen (BUN) and uric acid (UA) were detected biochemically. The pathological changes of the kidneys were observed under light and transmission electron microscopes. The expressions of TGF-ß1, FN and Col IV were detected by immunohistochemistry. RESULTS: The levels of the 24 h urinary protein, FBG, TG, Scr and BUN were elevated significantly in diabetic group(P<0.01). The glomerular volume of DM group rats became irregularly enlarged, diffused mesangial matrix accumulated, with basal membrane proliferous hypertrophy and fusion phenomenon of foot process, the expressions of TGF-ß1,FN and Col-IV were elevated significantly (P<0.05). After treated with L6H4, the levels of the 24 h urinary protein, FBG, TG, Scr and BUN were decreased in DT group compared to DM group (P<0.01), the morphological changes of kidney were ameliorated. The expression levels of TGF-ß1, FN and Col-IV were downregulated (P<0.05). CONCLUSIONS: L6H4 exerts the protective effect on kidneys of type 2 diabetic rats by reducing expression of TGF-ß1, inhibiting secretion of Col-IV and FN, relieving the deposition of the extracellular matrix.