Analysis of DNA methylation of perennial ryegrass under drought using the methylation-sensitive amplification polymorphism (MSAP) technique.

Perennial ryegrass (Lolium perenne), an excellent grass for forage and turf, is widespread in temperate regions. Drought is an important factor that limits its growth, distribution, and yield. DNA methylation affects gene expression and plays an important role in adaptation to adverse environments. In this study, the DNA methylation changes in perennial ryegrass under drought stress were assessed using methylation-sensitive amplified polymorphism (MSAP). After 15 days of drought stress treatment, the plant height was less than half of the control, and the leaves were smaller and darker. Genome-wide, a total of 652 CCGG sites were detected by MSAP. The total methylation level was 57.67 and 47.39 % in the control and drought treatment, respectively, indicating a decrease of 10.28 % due to drought exposure. Fifteen differentially displayed DNA fragments in MSAP profiles were cloned for sequencing analysis. The results showed that most of the genes involved in stress responses. The relative expression levels revealed that three demethylated fragments were up-regulated. The expression of a predicted retrotransposon increased significantly, changing from hypermethylation to non-methylation. Although the extent of methylation in two other genes decreased, the sites of methylation remained, and the expression increased only slightly. All of these results suggested that drought stress decreased the total DNA methylation level in perennial ryegrass and demethylation up-regulated related gene expressions and that the extent of methylation was negatively correlated with expression. Overall, the induced epigenetic changes in genome probably are an important regulatory mechanism for acclimating perennial ryegrass to drought and possibly other environmental stresses.

Levels of inflammatory cytokines in type 2 diabetes patients with different urinary albumin excretion rates and their correlation with clinical variables.

Although the pathogenetic mechanism of DN has not been elucidated, an inflammatory mechanism has been suggested as a potential contributor. This study was designed to explore the relationship between low-grade inflammation and renal microangiopathy in T2DM. A total of 261 diabetic subjects were divided into three groups according to UAE: a normal albuminuria group, a microalbuminuria group, and a macroalbuminuria group. A control group was also chosen. Levels of hs-CRP, TNF-α, uMCP-1, SAA, SCr, BUN, serum lipid, blood pressure, and HbA1c were measured in all subjects. Compared with the normal controls, levels of hs-CRP, TNF-α, uMCP-1, and SAA in T2DM patients were significantly higher. They were also elevated in the normal albuminuria group, P < 0.05. Compared with the normal albuminuria group, levels of these inflammatory cytokines were significantly higher in the microalbuminuria and macroalbuminuria group, P < 0.01. The macroalbuminuria group also showed higher levels than the microalbuminuria group, P < 0.01. Also they were positively correlated with UAE, SBP, DBP, LDL-C, and TC. We noted no significance correlated with course, TG, or HDL-C. Only TNF-α; was positively correlated with HbA1c. This study revealed the importance of these inflammatory cytokines in DN pathogenesis. Further studies are needed to fully establish the potential of these cytokines as additional biomarkers for the development of DN.

[Effect of mycophenolate on expression of MCP-1 and fibronectin in human mesangial cells induced by high glucose].

AIM: To investigate the effect of high glucose and mycophenolate (MMF) on the expression of MCP-1 in human mesangial cells (HMCs) and fibronectin (FN). METHODS: The HMCs were divided randomly into five groups: control group (5 mmol/L glucose), high glucose group (30 mmol/L glucose), mannitol group (5 mmol/L glucose and 25 mmol/L mannitol), high glucose+MMF-10 group (30 mmol/L glucose plus 10 µg/mL mycophenolate) and high glucose+MMF-100 group (30 mmol/L glucose plus 100 µg/mL mycophenolate). We detected the levels of MCP-1 and fibronectin in each group at 24 h, 48 h and 72 h, respectively. The expression levels of the MCP-1 mRNA were detected by RT-PCR, and the protein expression of MCP-1 and fibronectin was measured by ELISA. RESULTS: Compared with the control group, the levels of the MCP-1 and FN in high glucose group were significantly increased with the expression peak at 48 h (P<0.01). The MMF with different concentration could inhibit the expression of MCP-1 and FN in time- and dose-dependent manner (P<0.05). CONCLUSION: Mycophenolate could inhibit the expressions of MCP-1 and FN in human mesangial cells and it might be expected to delay the development and progression of glomerular sclerosis and interstitial fibrosis.

[The effect of fasudil via Rho/ROCK signaling pathway on the inflammation and fibrosis in human mesangial cells in high glucose medium].

OBJECTIVE: To study the effect of fasudil on inhibiting the Rho/ROCK signaling pathway under high glucose in human mesangial cells (HMCs) inflammation and fibrosis. METHODS: Synchronized HMCs were divided into following groups: (1) Normal glucose control group (NG, 5.5 mmol/L glucose); (2) High glucose group (HG, 30 mmol/L glucose); (3) Mannitol group (Man, 5.5 mmol/L glucose + 24.5 mmol/L mannitol); (4) High glucose + fasudil group (HG + F, the concentrations of fasudil were 25, 50 and 100 µmol/L, respectively). Collect the supernatant and cells at 0, 12, 24, 36, 48 and 72 h respectively, and determine the concentration changes of the RhoA, ROCK-I, connective tissue growth factor (CTGF)mRNA with real-time PCR method in the cells, then used the ELISA method to check the protein content of the fibronectin (FN), CTGF, TNFα in the supernatant. RESULTS: (1) RhoA, ROCK-I and CTGF mRNA of the HMCs cultured under the high glucose expressed significantly higher than those in the normal group, and there was certain time-dependence. Besides, there was no statistic significance by comparing Man and NG. (2)Under the high glucose situation, after the fasudil pretreatment with different concentrations and 24 h or 48 h culture with high glucose, RhoA, ROCK-I, CTGF mRNA expression was significantly decreased in HG + F, compared with HG, and there was certain concentration-dependence. (3) High glucose increased the FN, CTGF, TNFα protein secretion of HMCs in a time-dependent manner, but normal glucose and mannitol had no such effect. (4) After the fasudil pretreatment with different concentrations and culture with high glucose for 12, 24, 36, 48, 72 h, the FN, CTGF, TNFα protein secretion was significantly reduced compared with HG. CONCLUSION: Fasudil can reduce the secretion of downstream inflammatory factors and cytokines by inhibiting high glucose-activated HMCs Rho/ROCK signaling pathway, and reduce the inflammation and fibrosis of HMCs. This provides a new basis for the therapeutic target in the treatment of diabetic nephropathy.

[Effects of inhibiting RhoA by Stealth RNA on high glucose-induced RhoA/ROCK signaling pathway in human mesangial cells].

OBJECTIVE: To observe the effect of small interference RNA (Stealth RNAiTM siRNA) of RhoA on the inflammatory response and fibrosis in human mesangial cell (HMC) and explore the role of RhoA/ROCK signaling pathway in the process of diabetic nephropathy. METHODS: Synchronized HMC were divided into several groups. Lipofectamine(TM)2000 was employed to transfect RhoA-siRNA and RhoA-negative siRNA into the above cells. RhoA-siRNA could inhibit the expression of RhoA. The expressions of RhoA, ROCK-I, fibronectin (FN), connective tissue growth factor (CTGF) and tumor necrosis factor-alpha (TNF-α) were detected by real-time reverse transcription-polymerase chain reaction (RT-PCR) and ELISA (enzyme-linked immunosorbent assay). RESULTS: (1) The expressions of RhoA, ROCK-I and CTGF mRNA were inhibited by RhoA siRNA transfection in high glucose-induced HMC. The expression of each mRNA was reduced 26% - 60% as compared with the high glucose-induced group (P < 0.05); (2) After RhoA siRNA transfection and culturing with high glucose for 48 h, FN, the secretions of CTGF and TNF-α significantly declined [FN: (1.99 ± 0.04) mg/L vs. (4.31 ± 0.13) mg/L, CTGF:(4.98 ± 0.17) mg/L vs. (6.06 ± 0.09) mg/L; TNF-α: (61.17 ± 2.59) ng/L vs.(91.76 ± 2.27) ng/L, all P < 0.05]. The levels of FN and CTGF almost decreased to those of normal glucose-induced HMC. CONCLUSION: The levels of FN, CTGF and TNF-α in high glucose-induced HMC may be lowered by inhibiting RhoA through RNA interference and reducing the accumulation of extracellular matrix, glomerular fibrosis and inflammation. Thus it provides a new intervention target for the prevention of diabetic nephropathy.