Role of plant autophagy in stress response

Autophagy is a conserved pathway for the bulk degradation of cytoplasmic components in all eukaryotes. This process plays a critical role in the adaptation of plants to drastic changing environmental stresses such as starvation, oxidative stress, drought, salt, and pathogen invasion. This paper summarizes the current knowledge about the mechanism and roles of plant autophagy in various plant stress responses.

Inhibition of Tanshinone Ⅱ A on cardiac aldosterone synthesis and relevant genic expression in hypertension / 中国组织工程研究

BACKGROUND:Aldosterone is main pathogenic factor of left ventricular hypertrophy, for which, to inhibit its biosynthesis effectively may prevent and treat hypertension induced by left ventricular hypertrophy.OBJECTIVE: To investigate the effects of Tanshinone Ⅱ A on myocardiac aldosterone synthesis and expression of its relevant genic CYP11B1and CYP1 1B2 in spontaneously hypertensive rats(SHR) and explore the possi ble nechanism of Tanshinone Ⅱ A on inhibiting hypertension induced by left ventricular hypertrophy.DESIGN:SHR were employed as the objects in the experiment and WKY rats with normal blood pressure (WKY rats) were employed in the controlgroup. Complete group division and randomized control experiment was designed. Analysis of variance was used for the means comparison among groups.SETTING :Department of Emergency and Institute of Integrated Traditional Chinese and Western Medicine in Tongji Hospital Affiliated to Tongji Medical College of Huazhong University of Science and Technology.MATERIALS :The experiment was performed in the laboratory of Department of Emergency in Tongji Hospital Affiliated to Tongji Medical College of Huazhong University of Science and Technology from January 2003 to February 2004, in which, 10 male WKY rats with normal blood pressure of 12-week-old were employed in the control group and 20 male SHR of 12-week-old were randomized into two groups, named hypertension group and Tanshinone ⅡA group, 10 rats each group.METHODS:In Tanshinone Ⅱ A group, Tanshinone Ⅱ A 1.5 mg/kg was injected abdominally everyday. The distilled water of same volume was injected abdominally in hypertension group and the control group. Twelve weeks after experiment, myocardial specimens were collected after rats sacrificed. Radioimmunoassay was used to determine the contents of aldosteron and angiotensin Ⅱ in myocardial tissue and reverse transcriptase polymerase chain reaction (RT-PCR) were used to measure mRNA level of CYP11B1 and CYP11B2 genes relevant to aldosterone synthesis.MAIN OUTCOME MEASURES: Contents of aldosterone and angiotensin Ⅱ in myocardial tissue and mRNA expression of CYP11B1 and CYP1 1B2 genes.RESULTS:All of 20 SHR and 10 WKY rats entered result analysis. ① Myocardial aldosterone content of rats in 12 weeks after experiment: that in hypertension group and Tanshinone Ⅱ A group was higher remarkably than that in the control group [(0.056±0.014), (0.031±0.010), (0.018±0.009) ng/g,P ＜ 0.01, 0.05]; that in Tanshione Ⅱ A group was lower remarkably than that in the hypertension group (P ＜ 0.05). ② Myocardial angiotension Ⅱ content of rats in 12 weeks after experiment: that in the hypertension group and Tanshinone ⅡA group was higher remarkably than that in the control group [(0.093±0.016), (0.088±0.024), (0.043±0.012) ng/L, P ＜ 0.01]. ③ Expression of CYP11B1 gene in myocardial tissue of rats in 12 weeks after experiment: that in the hypertension group and Tanshinone Ⅱ A group was higher remarkably than that in the control group (2.774±0.138, 2.533 ±0.127, 1.973±0.102, P ＜ 0.05). ④Expression of CYP11B2 gene in myocardial tissue of rats in 12 weeks after experiment; that in the hypertension group and Tanshinone ⅡA group was higher remarkably than that in the control group (1.573±0.106, 1.024±0.113, 0.786±0.121, P ＜ 0.01,0.05); that in the Tanshinone ⅡA group was lower remarkably than that in the hypertension group (P ＜ 0.05). ⑤The electrophoresis band positions of myocardial CYP11B1 and CYP11B2 as well as RT-PCR products of glyceraldehydes-3-phosphate dehydrogenase (GAPDH), the consulting gene,were in conformity with the theoretic values.CONCLUSION:The inhibition of Tanshinone Ⅱ A on hypertension induced by left ventricular hypertrophy is probably contributed to its downregulating effect on myocardiac CYP11B2 gene expression relevant to aldosterone synthesis and to its reducing action on local biosynthesis of aldosterone in heart.

Effects of Tanshinone ⅡA on inhibition of biological synthesis of aldosterone / 中国组织工程研究

BACKGROUND: Aldosterone is an important pathogenic factor of left ventricular hypertrophy. There has been evidence that the extract of red sage root (a Chinese herb) can intervene the synthesis of aldosterone.OBJECTIVE: To investigate the effects of tanshinone Ⅱ A on expression of genes related to aldosterone synthesis in myocardium. DESIGN:A randomized and controlled trial. SETTING :Tongji Hospital Affiliated to Tongji Medical College, Huazhong University of Science and Technology. MATERIALS:The experiment was performed at the laboratory of Emergency Department, Tongji Hospital Affiliated to Tongji Medical College,Huazhong University of Science and Technology from November 2002 to March 2004. Totally 20 male 12-week-old rats with spontaneous hypertension were randomly divided as hypertension group and tanshinone Ⅱ A group. METHODS:Rats in each group were injected tanshinone Ⅱ A or distilled water in the same volume respectively through caudal vein. After 12-week administration,the rats were put to death by decapitation, and the samples of myocardium were prepared. The expressions of CYP11B1mRNA and CYP11B2 mRNA, or myocardial genes related to aldosterone synthesis were examined with reverse transcriptase polymerase chain reaction (RTPCR) and referring to the amplification primers of glyceraldehydes 3-phosphate dehydrogenase (GAPDH) gene. MAIN OUTCOME MEASURES:The levels of CYP11B1 and CYP11B2 mRNA related to aldosterone synthesis in myocardium.RESULTS :Totally 20 rats were involved in the trial and all entered in the final result analysis without any loss of value. ① Quantitative analysis of expression of myocardial CYP11B1 and CYP11B2 genes in rats of two groups: Taking 100bp Plus Ladder as Marker,clear amplified strands could be seen at 440bp,461bp and 336bp sites,DNA sequencing proved they were the encoding gene segments of CYP11B1,YP11B2 and GAPDH. ②Qualitative analysis of expression of myocardial CYP11B1 and CYP11B2 genes in rats of two groups:The expressive levels of CYP11B1 and CYP1 1B2 mRNA contents in tanshinone Ⅱ A group were significantly lower than those in hypertension group (0.924±0.121 vs 1.343±0.132,P ＜ 0.05;1.017±0.119 vs 1.675±0.126,P 0.01). CONCLUSION:Tanshinone Ⅱ A could directly down-regulate the expression of CYP1 1B1 and CYP1 1B2 mRNA, the genes related to aldosterone syn thesis, so that it inhibited the biological synthesis of aldosterone in myocardinm, thus playing a role to resist hypertensive left ventricular hypertrophy.

Effect of Salvia miltiorrhiza on left ventricular hypertrophy and cardiac aldosterone in spontaneously hypertensive rats / 华中科技大学学报（医学）（英德文版）

Chronic treatment with Salvia Miltiorrhiza preventing left ventricular hypertrophy (LVH) and its possible mechanism--inhibiting the action of cardiac aldosterone in spontaneously hypertensive rats (SHR) were investigated. Normotensive Wistar-kyoto (WKY) rats and SHRs were used. Part of SHRs was treated with Salvia Miltiorrhiza for 12 weeks. Systolic blood pressure (SBP) and left ventricular mass index were measured. Sections of heart tissue were stained with HE method and VanGieson method. Collagen volume fraction was determined in the left ventricle by automatically quantitative morphometry. Cardiac aldosterone concentration was measured by radioimmunoassay. The results indicated that compared with WKY rats, SHRs exhibited higher SBP, left ventricular collagen volume fraction, and aldosterone concentration (all P < 0.05). After the treatment with Salvia Miltiorrhiza, SBP, left ventricular collagen volume fraction, and aldosterone concentration in SHR were decreased as compared with control group (P < 0.05) except SBP. It was concluded that chronic treatment with Salvia Miltiorrhiza could prevent left ventricular hypertrophy in SHR, significantly inhibit collagen compositions in left ventricle. The mechanism was probably related with the inhibition of the cardiac aldosterone action.

The regulation of peroxisome proliferator-activated receptor-? on apoptotic related genes p53 and bcl-2 in cultured vascular smooth muscle cells / 中国病理生理杂志

AIM: We sought to evaluate the expression of apoptosis related genes, p53 and bcl-2, in cultured vascular smooth muscle cells (VSMCs) in which apoptosis was induced by the ligands of PPAR?-ox-LDL,ciglitazone and 15-deoxy-△ 12,14-PGJ 2,and then influenced by PGF 2?,an antagonist of PPAR?. To clarify whether PPAR? is involved in the regulations of p53 and bcl-2.METHODS: Rat aorta smooth muscle cells were isolated and cultured in DMEM containing 10%FBS. ox-LDL,ciglitazone and 15 d-PGJ 2 were added into the medium for 24 h, respectively. Using PGF 2? to inhibit PPAR? activation via activation of MAP kinase. We employed the flow cytometry analysis to quantitatively analyze the apoptosis of VSMCs. Also, we measured and analyzed the discrepancies of the expression of p53 and bcl-2 between every groups. RESULTS: During the process of apoptosis induced by PPAR?,the expression of P53 protein increased (P