Maize PIMT2 repairs damaged 3-METHYLCROTONYL COA CARBOXYLASE in mitochondria, affecting seed vigor.

PROTEIN l-ISOASPARTYL O-METHYLTRANSFERASE (PIMT) affects seed vigor by repairing damaged proteins. While PIMT is capable of isoaspartyl (isoAsp) repair in all proteins, those proteins most susceptible to isoAsp formation have not been well characterized, and the mechanisms by which PIMT affects seed vigor remain largely unknown. Using co-immunoprecipitation and LC-MS/MS, we found that maize (Zea mays) PIMT2 (ZmPIMT2) interacted predominantly with both subunits of maize 3-METHYLCROTONYL COA CARBOXYLASE (ZmMCC). ZmPIMT2 is specifically expressed in the maize embryo. Both mRNA and protein levels of ZmPIMT2 increased during seed maturation and declined during imbibition. Maize seed vigor was decreased in the zmpimt2 mutant line, while overexpression of ZmPIMT2 in maize and Arabidopsis thaliana increased seed vigor upon artificial aging. ZmPIMT2 was localized in the mitochondria, as determined by subcellular localization assays using maize protoplasts. ZmPIMT2 binding to ZmMCCα was confirmed by luciferase complementation tests in both tobacco (Nicotiana benthamiana) leaves and maize protoplasts. Knockdown of ZmMCCα decreased maize seed aging tolerance. Furthermore, overexpression of ZmPIMT2 decreased the accumulation of isoAsp of ZmMCCα protein in seed embryos that underwent accelerated aging treatment. Taken together, our results demonstrate that ZmPIMT2 binds ZmMCCα in mitochondria, repairs isoAsp damage, and positively affects maize seed vigor.

[MicroRNA-223-3p inhibits the angiogenesis of ischemic myocardial microvascular endothelial cells via modulating Rps6kb1/HIF-1α signal pathway].

OBJECTIVE: To explore the role of microRNA on the myocardial microvascular endothelial cells (CMECs) of ischemic heart rats in the process of angiogenesis and related regulation mechanism. METHODS: Myocardial ischemic rats model was established by coronary ligation.Seven days after operation, the ischemic CMECs were cultured by the method of planting myocardium tissue and identified by immunocytochemistry to observe the biological characteristics of ischemic CMECs angiogenesis, to determine the window period of migration, proliferation, tube formation in the process of its angiogenesis. Dynamic expression changes of microRNA in the process of ischemic CMECs angiogenesis was detected using microRNA chip and further verified by real-time PCR, the core microRNA of the ischemic CMECs was defined and the predicted target genes of core microRNA were determined by bioinformatics methods and real-time PCR. At the same time, the protein expression of target gene and angiogenesis related genes of p38MAPK, PI3K,Akt,VEGF were measured by Western blot. RESULTS: The CMECs of rats presented typical characteristics of microvascular endothelial cells, and factor VIII, CD31 related antigens were all positively stained by immunocytochemical analysis. The migration window period was on the first day, and the tube formation window period was on the second day of both control and ischemic groups, while the proliferation window period was on the third day for the normal group, and the sixth day for ischemic group. According to the expressional difference and their relationship with angiogenesis, miRNA-223-3p was ultimately determined as the core microRNA in the process of ischemic CMECs angiogenesis, real-time PCR verified this hypothesis. Bioinformatics methods predicted that Rps6kb1 is the target genes of miRNA-223-3p, the pathway analysis showed that Rps6kb1 could regulate angiogenesis via HIF-1α signal pathway. Moreover, the mRNA and protein expression of VEGF, p38MAPK, PI3K,Akt, which were the downstream molecules of Rps6kb1/HIF-1α signal pathway, were also significantly downregulated in ischemic CMECs from migration and proliferation stage. CONCLUSION: Our results show that the miRNA-223-3p is the core microRNA of ischemic CMECs angiogenesis. MiRNA-223-3p could regulate Rps6kb1/HIF-1α signal pathway, inhibit the process of migration and proliferation of ischemic CMECs angiogenesis. MiRNA-223-3p is thus likely to be a core target for enhancing angiogenesis of ischemic heart disease.

[Chinese herbs for shen invigorating and blood activating activated MMP-9 signaling pathway to mobilize rats' bone marrow EPCs: a molecular mechanism research].

OBJECTIVE: To explore the effect of Chinese herbs for Shen invigorating and blood activating (CHSIBA) on the number of endothelial progenitor cells (EPCs) in the bone marrow and the peripheral blood and the signaling pathway of bone marrow matrix metalloproteinase 9 (MMP-9) of the myocardial infarction (MI) model rats. METHODS: The MI rat model was established by ligation. Thirty successfully modeled rats were randomly divided into the high dose CHSIBA group, the low dose CHSIBA group, and the model group, 10 in each group. Besides, another 10 normal rats were recruited as the blank group. Rats in the high dose CHSIBA group and the low dose CHSIBA group were administered with CHSIBA at 3 g/kg and 1.5 g/kg body weight by gastrogavage (by adding them in 4 mL physiological saline), once daily. Rats in the model group and the blank group were administered with 4 mL physiological saline once daily. The EPCs were collected from the bone marrow and the peripheral blood 4 weeks later. Seven days later the CD34/CD133 phenotype was identified in collected sticking wall cells using flow cytometry. The MMP-9 and water soluble Kit ligand (sKitL) were detected using Western blot. The expressions of vascular endothelial growth factor (VEGF) and stromal cell-derived factor-1alpha (SDF-1alpha) were detected using ELISA. RESULTS: The CD34/CD133 positive rate and the EPC quantity in the bone marrow and the peripheral blood were higher in the high dose CHSIBA group and the low dose CHSIBA group than in the model group (P < 0.05, P < 0.01). Besides, the expressions of VEGF, SDF-1alpha, MMP-9, and sKitL in the bone marrow and the peripheral blood were also higher in the high dose CHSIBA group and the low dose CHSIBA group than in the model group (P < 0.05, P < 0.01). CONCLUSION: CHSIBA could activate MMP-9 signaling pathway, increase its upstream and downstream signal expression levels, and mobilize EPCs in the bone marrow to enter the blood circulation.

Qi-Shen-Yi-Qi Dripping Pills Promote Angiogenesis of Ischemic Cardiac Microvascular Endothelial Cells by Regulating MicroRNA-223-3p Expression.

Traditional Chinese medicine (TCM) research shows that Qi-Shen-Yi-Qi Dripping Pills (QSYQ) can promote ischemic cardiac angiogenesis. Studies have shown that microRNAs (miRNAs) are the key component of gene regulation networks, which play a vital role in angiogenesis and cardiovascular disease. Mechanisms involving miRNA by which TCM promotes ischemic cardiac angiogenesis have not been reported. We found that microRNA-223-3p (mir-223-3p) was the core miRNA of angiogenesis of rats ischemic cardiac microvascular endothelial cells (CMECs) and inhibited angiogenesis by affecting RPS6KB1/HIF-1α signal pathway in previous study. Based on the results, we observed biological characteristics and optimal dosage for QSYQ intervening in rats ischemic CMECs angiogenesis and concluded that QSYQ low-dose group had the strongest ability to promote angiogenesis of ischemic myocardium. Using miRNA chip and real-time PCR techniques in this study, we identified mir-223-3p as the pivotal miRNA in QSYQ that regulated angiogenesis of ischemic CMECs. From real-time PCR and western blot analysis, research showed that gene and protein expression of factors located RPS6KB1/HIF-1α signaling pathway, including HIF-1α, VEGF, MAPK, PI3K, and AKT, were significantly upregulated by QSYQ to regulate angiogenesis of ischemic CMECs. This study showed that QSYQ promote ischemic cardiac angiogenesis by downregulating mir-223-3p expression in rats ischemic CMECs.

MicroRNA-223-3p inhibits the angiogenesis of ischemic cardiac microvascular endothelial cells via affecting RPS6KB1/hif-1a signal pathway.

BACKGROUND: MicroRNAs (miRNAs) are a recently discovered class of posttranscriptional regulators of gene expression with critical functions in the angiogenesis and cardiovascular diseases; however, the details of miRNAs regulating mechanism of angiogenesis of ischemic cardiac microvascular endothelial cells (CMECs) are not yet reported. METHODS AND RESULTS: This study analyzes the changes of the dynamic expression of miRNAs during the process of angiogenesis of ischemic CMECs by applying miRNA chip and real-time PCR for the first time. Compared with normal CMECs, ischemic CMECs have a specific miRNAs expression profile, in which mir-223-3p has the most significant up-regulation, especially during the process of migration and proliferation, while the up-regulation is the most significant during migration, reaching 11.02 times. Rps6kb1 is identified as a potential direct and functional target of mir-223-3p by applying bioinformatic prediction, real-time PCR and Western blot. Pathway analysis report indicates Rps6kb1 regulates the angiogenesis by participating into hif-1a signal pathway. Further analysis reveals that both the gene and protein expression of the downstream molecules VEGF, MAPK, PI3K and Akt of Rps6kb1/hif-1a signal pathway decrease significantly during the process of migration and proliferation in the ischemic CMECs. Therefore, it is confirmed that mir-223-3p inhibits the angiogenesis of CMECs, at least partly, via intervening RPS6KB1/hif-1a signal pathway and affecting the process of migration and proliferation. CONCLUSION: This study elucidates the miRNA regulating law in the angiogenesis of CMECs; mir-223-3p inhibits the process of migration and proliferation of ischemic CMECs probably via affecting RPS6KB1/hif-1a signal pathway, which in turn suppresses the angiogenesis. It is highly possible that mir-223-3p becomes a novel intervention core target in the treatment of angiogenesis of ischemic heart diseases.