Bark tissue transcriptome analyses of inverted Populus yunnanensis cuttings reveal the crucial role of plant hormones in response to inversion.

Inverted cuttings of Populus yunnanensis exhibit an interesting growth response to inversion. This response is characterized by enlargement of the stem above the shoot site, while the upright stem shows obvious outward growth below the shoot site. In this study, we examined transcriptome changes in bark tissue at four positions on upright and inverted cuttings of P. yunnanensis: position B, the upper portion of the stem; position C, the lower portion of the stem; position D, the bottom of new growth; and position E, the top of new growth. The results revealed major transcriptomic changes in the stem, especially at position B, but little alteration was observed in the bark tissue of the new shoot. The differentially expressed genes (DEGs) were mainly assigned to four pathways: plant hormone signal transduction, plant-pathogen interaction, mitogen-activated protein kinase (MAPK) signaling pathway-plant, and adenosine triphosphate-binding cassette (ABC) transporters. Most of these DEGs were involved in at least two pathways. The levels of many hormones, such as auxin (IAA), cytokinin (CTK), gibberellins (GAs), ethylene (ET), and brassinosteroids (BRs), underwent large changes in the inverted cuttings. A coexpression network showed that the top 20 hub unigenes at position B in the upright and inverted cutting groups were associated mainly with the BR and ET signaling pathways, respectively. Furthermore, brassinosteroid insensitive 1-associated receptor kinase 1 (BAK1) in the BR pathway and both ethylene response (ETR) and constitutive triple response 1 (CTR1) in the ET pathway were important hubs that interfaced with multiple pathways.

[Relationship between six single nucleotide polymorphisms of angiotensinogen gene and essential hypertension].

OBJECTIVE: To evaluate the relationship of six single nucleotide polymorphisms(SNPs) and their haplotypes of angiotensinogen(AGT) gene to essential hypertension(EH) in Chinese Han population. METHODS: The genotypes in 185 patients with EH and 185 healthy controls were determined by the method of ABI PRISM SNaPshot Multiplex Kit using six AGT gene polymorphisms at position -217(G/A), -152(G/A), -20(A/C) and -6(G/A) in the promoter region and T174M, M235T in exon 2. RESULTS: The distribution of AGT genotypes and alleles frequencies showed no significant difference between the group of EH and group of controls (P>0.05). However, haplotype analysis revealed that H4 haplotype frequency, which included -152A, -20C, -6A and 235T alleles, was significantly increased in the group of EH (P<0.05). CONCLUSION: G-152A, A-20C, G-6A and M235T polymorphisms of AGT gene might play an important role in the occurrence of EH in Chinese Han population.

Single nucleotide polymorphisms in promoter of angiotensin II type 1 receptor gene associated with essential hypertension and coronary heart disease in Chinese population.

AIM: To discover single nucleotide polymorphisms (SNPs) in the promoter region of angiotensin II type 1 receptor (AT1) gene and evaluate their associations with the occurrence of essential hypertension (EH) and coronary heart disease (CHD) in Chinese Han population. METHODS: SNPs detection was performed by PCR-sequencing. The genotype was determined by the same method in a total number of 473 unrelated patients including 160 EH cases, 128 CHD cases, and 185 EH combined with CHD cases as well as 160 healthy controls. RESULTS: Six SNPs were discovered in the promoter region of AT1 gene. -810A/T was almost in completely linkage disequilibrium with -713G/T, -214A/C, -213G/C, and -153A/G polymorphisms. No statistically association was found in our population between -810A/T polymorphism and EH, the association of -810A allele and CHD was of borderline significant (chi2=3.649, P=0.056). However, significant differences of genotype distributions were observed in the EH combined with CHD group (TT=126, TA=51, AA=8) compared with the EH patients (TT=127,TA=26, AA=7, chi2=6.410, P=0.041) and the healthy controls (TT=130, TA=24, AA=6, chi2=7.742, P=0.021). The EH combined with CHD patients had a significantly increased A allele frequency than the normal references (0.181 vs 0.106, chi2=7.690, P=0.006) and the EH subjects (0.181 vs 0.125, chi2=4.119, P=0.042). Hypertensive patients carrying TA genotype (OR=1.977, 95 % CI 1.160-3.354, P=0.011) or A allele (OR=1.548, 95 % CI 1.015-2.361, P=0.043) had an increased risk for CHD morbidity. CONCLUSION: we firstly report that -810A/T polymorphism in the promoter region of AT1 gene might be a genetic risk factor for the pathogenesis of CHD complicated with EH in Chinese Han population.

High glucose enhance expression of matrix metalloproteinase-2 in smooth muscle cells.

AIM: To investigate the effects of high glucose on expression of matrix metalloproteinase-2 (MMP-2) in rat aortic smooth muscle cells and the influence of matrix remodeling on atherogenesis in diabetic patients. METHODS: The smooth muscle cells were cultured from the thoracic aorta of Sprague-Dawley (SD) rat. MMP-2 mRNA was determined by reverse transcriptase-polymerase chain reaction (RT-PCR), MMP-2 protein was measured by Western blotting, and MMP-2 activity in conditioned medium was observed by zymography. RESULTS: In comparison with the control, there was no difference in the expression of MMP-2 when glucose concentration was 1 g/L, whereas MMP-2 activity in smooth muscle cells was significantly increased by the glucose 5 g/L (P<0.01). CONCLUSION: High glucose enhanced the expression and activity of MMP-2 in smooth muscle cells, which may provide an explanation for the phenomenon that diabetes patients are prone to have atherosclerotic lesions.