Age-Based Differences in the Genetic Determinants of Glycemic Control: A Case of FOXO3 Variations

BackgroundGlucose homeostasis is a trait of healthy ageing and is crucial to the elderly, but less consideration has been given to the age composition in most studies involving genetics and hyperglycemia.MethodsSeven variants in FOXO3 were genotyped in three cohorts (n = 2037; LLI, MI_S and MI_N; mean age: 92.5±3.6, 45.9±8.2 and 46.8±10.3, respectively) to compare the contribution of FOXO3 to fasting hyperglycemia (FH) between long-lived individuals (LLI, aged over 90 years) and middle-aged subjects (aged from 35–65 years).ResultsA different genetic predisposition of FOXO3 alleles to FH was observed between LLI and both of two middle-aged cohorts. In the LLI cohort, the longevity beneficial alleles of three variants with the haplotype “AGGC” in block 1 were significantly protective to FH, fasting glucose, hemoglobin A_1C and HOMA-IR. Notably, combining multifactor dimensionality reduction and logistic regression, we identified a significant 3-factor interaction model (rs2802288, rs2802292 and moderate physical activity) associated with lower FH risk. However, not all of the findings were replicated in the two middle-aged cohorts.ConclusionOur data provides a novel insight into the inconsistent genetic determinants between middle-aged and LLI subjects. FOXO3 might act as a shared genetic predisposition to hyperglycemia and lifespan.     

Effects of Simulated Nitrogen Deposition on Soil Respiration in a Populus euphratica Community in the Ebinur Lake Area,a Desert Ecosystem of Northwestern China

One of the primary limiting factors for biological activities in desert ecosystems is nitrogen (N). This study therefore examined the effects of N and investigated the responses of an arid ecosystem to global change. We selected the typical desert plant Populus euphratica in a desert ecosystem in the Ebinur Lake area to evaluate the effects of N deposition on desert soil respiration. Three levels of N deposition (0, 37.5 and 112.5 kg·N·ha^-1·yr^-1) were randomly artificially provided to simulate natural N deposition. Changes in the soil respiration rates were measured from July to September in both 2010 and 2013, after N deposition in April 2010. The different levels of N deposition affected the total soil N, soil organic matter, soil C/N ratio, microorganism number, and microbial community structure and function. However, variable effects were observed over time in relation to changes in the magnitude of N deposition. Simulated high N deposition significantly reduced the soil respiration rate by approximately 23.6±2.5% (P<0.05), whereas low N deposition significantly increased the soil respiration rate by approximately 66.7±2.7% (P<0.05). These differences were clearer in the final growth stage (September). The different levels of N deposition had little effect on soil moisture, whereas N deposition significantly increased the soil temperature in the 0–5 cm layer (P<0.05). These results suggest that in the desert ecosystem of the Ebinur Lake area, N deposition indirectly changes the soil respiration rate by altering soil properties.     

Mefunidone Attenuates Tubulointerstitial Fibrosis in a Rat Model of Unilateral Ureteral Obstruction

Background

Inflammation has a crucial role in renal interstitial fibrosis, which is the common pathway of chronic kidney diseases. Mefunidone (MFD) is a new compound which could effectively inhibit the proliferation of renal fibroblasts in vitro. However, the overall effect of Mefunidone in renal fibrosis remains unknown.

Methods

Sprague-Dawley rats were randomly divided intro 6 groups: sham operation, unilateral ureteral obstruction (UUO), UUO/Mefunidone (25, 50, 100mg/kg/day) and UUO/PFD (500mg/kg/day). The rats were sacrificed respectively on days 3, 7, and 14 after the operation. Tubulointerstitial injury index, interstitial collagen deposition, expression of fibronectin (FN), α-smooth muscle actin (α-SMA), type I and III collagen and the number of CD3+ and CD68+ cells were determined. The expressions of proinflammatory cytokines, p-ERK, p-IκB, and p-STAT3 were measured in human renal proximal tubular epithelial cells of HK-2 or macrophages.

Results

Mefunidone treatment significantly attenuated tubulointerstitial injury, interstitial collagen deposition, expression of FN, α-SMA, type I and III collagen in the obstructive kidneys, which correlated with significantly reduced the number of T cells and macrophages in the obstructive kidneys. Mechanistically, Mefunidone significantly inhibited tumor necrosis factor-α (TNF-α-) or lipopolysaccharide (LPS)-induced production of proinflammatory cytokines. This effect is possibly due to the inhibition of phosphorylation of ERK, IκB, and STAT3.

Conclusion

Mefunidone treatment attenuated tubulointerstitial fibrosis in a rat model of UUO, at least in part, through inhibition of inflammation.     

Oryza sativa Chloroplast Signal Recognition Particle 43 (OscpSRP43) Is Required for Chloroplast Development and Photosynthesis

A rice chlorophyll-deficient mutant w67 was isolated from an ethyl methane sulfonate (EMS)–induced IR64 (Oryza sativa L. ssp. indica) mutant bank. The mutant exhibited a distinct yellow-green leaf phenotype in the whole plant growth duration with significantly reduced levels of chlorophyll and carotenoid, impaired chloroplast development and lowered capacity of photosynthesis compared with the wild-type IR64. Expression of a number of genes associated with chlorophyll metabolism, chloroplast biogenesis and photosynthesis was significantly altered in the mutant. Genetic analysis indicated that the yellow-green phenotype was controlled by a single recessive nuclear gene located on the short arm of chromosome 3. Using map-based strategy, the mutation was isolated and predicted to encode a chloroplast signal recognition particle 43 KD protein (cpSRP43) with 388 amino acid residuals. A single base substitution from A to T at position 160 resulted in a premature stop codon. OscpSRP43 was constitutively expressed in various organs with the highest level in the leaf. Functional complementation could rescue the mutant phenotype and subcellular localization showed that the cpSRP43:GFP fusion protein was targeted to the chloroplast. The data suggested that Oryza sativa cpSRP43 (OscpSRP43) was required for the normal development of chloroplasts and photosynthesis in rice.     

Discovery of a Novel Immune Gene Signature with Profound Prognostic Value in Colorectal Cancer: A Model of Cooperativity Disorientation Created in the Process from Development to Cancer

Immune response-related genes play a major role in colorectal carcinogenesis by mediating inflammation or immune-surveillance evasion. Although remarkable progress has been made to investigate the underlying mechanism, the understanding of the complicated carcinogenesis process was enormously hindered by large-scale tumor heterogeneity. Development and carcinogenesis share striking similarities in their cellular behavior and underlying molecular mechanisms. The association between embryonic development and carcinogenesis makes embryonic development a viable reference model for studying cancer thereby circumventing the potentially misleading complexity of tumor heterogeneity. Here we proposed that the immune genes, responsible for intra-immune cooperativity disorientation (defined in this study as disruption of developmental expression correlation patterns during carcinogenesis), probably contain untapped prognostic resource of colorectal cancer. In this study, we determined the mRNA expression profile of 137 human biopsy samples, including samples from different stages of human colonic development, colorectal precancerous progression and colorectal cancer samples, among which 60 were also used to generate miRNA expression profile. We originally established Spearman correlation transition model to quantify the cooperativity disorientation associated with the transition from normal to precancerous to cancer tissue, in conjunction with miRNA-mRNA regulatory network and machine learning algorithm to identify genes with prognostic value. Finally, a 12-gene signature was extracted, whose prognostic value was evaluated using Kaplan–Meier survival analysis in five independent datasets. Using the log-rank test, the 12-gene signature was closely related to overall survival in four datasets (GSE17536, n = 177, p = 0.0054; GSE17537, n = 55, p = 0.0039; GSE39582, n = 562, p = 0.13; GSE39084, n = 70, p = 0.11), and significantly associated with disease-free survival in four datasets (GSE17536, n = 177, p = 0.0018; GSE17537, n = 55, p = 0.016; GSE39582, n = 557, p = 4.4e-05; GSE14333, n = 226, p = 0.032). Cox regression analysis confirmed that the 12-gene signature was an independent factor in predicting colorectal cancer patient’s overall survival (hazard ratio: 1.759; 95% confidence interval: 1.126–2.746; p = 0.013], as well as disease-free survival (hazard ratio: 2.116; 95% confidence interval: 1.324–3.380; p = 0.002).     

Effects of Bifidobacterium Breve Feeding Strategy and Delivery Modes on Experimental Allergic Rhinitis Mice

BackgroundDifferent delivery modes may affect the susceptibility to allergic diseases. It is still unknown whether early intervention with probiotics would counteract this effect.ObjectivesThe effect of different delivery modes on immune status and nasal symptoms was investigated on established allergic rhinitis (AR) mouse model. In addition, the immunoregulatory effects and mechanisms of different feeding manners with Bifidobacterium breve(B. breve) were examined.MethodsLive lyophilized B. breve was orally administered to BALB/c mice born via vaginal delivery(VD) or cesarean delivery (CD) for 8 consecutive weeks, after which they were sensitized by ovalbumin(OVA) to establish experimental AR. Nasal symptoms, serum immunoglobulins, cytokines, splenic percentages of CD4⁺CD25⁺Foxp3⁺ regulatory T(Treg) cells and nasal eosinophil infiltration were evaluated.ResultsCompared with VD mice, mice delivered via CD demonstrated more serious nasal symptoms, higher concentrations of OVA-specific immunoglobulin (Ig) E, more nasal eosinophils and lower percentages of splenic CD4⁺CD25⁺Foxp3⁺Treg cells after establishing experimental AR. These parameters were reversed by administering B. breves hortly after birth. However, the effect of B. breve did not differ between different delivery modes.ConclusionCD aggravates the nasal symptoms of AR mice compared to VD. This is the first report that oral administration of B. breve shortly after birth can significantly alleviate the symptoms of AR mice born via both deliveries, probably via activation of the regulatory capacity of CD4⁺CD25⁺Foxp3⁺Treg cells.     

METTL3/N6‐methyladenosine/ miR‐21‐5p promotes obstructive renal fibrosis by regulating inflammation through SPRY1/ERK/NF‐κB pathway activation

Renal fibrosis induced by urinary tract obstruction is a common clinical occurrence; however, effective treatment is lacking, and a deeper understanding of the mechanism of renal fibrosis is needed. Previous studies have revealed that miR‐21 impacts liver and lung fibrosis progression by activating the SPRY1/ERK/NF‐kB signalling pathway. However, whether miR‐21 mediates obstructive renal fibrosis through the same signalling pathway has not been determined. Additionally, studies have shown that N6‐methyladenosine (m⁶A) modification‐dependent primary microRNA (pri‐microRNA) processing is essential for maturation of microRNAs, but its role in the maturation of miR‐21 in obstructive renal fibrosis has not yet been investigated in detail. To address these issues, we employed a mouse model of unilateral ureteral obstruction (UUO) in which the left ureters were ligated for 3, 7 and 14 days to simulate the fibrotic process. In vitro, human renal proximal tubular epithelial (HK‐2) cells were transfected with plasmids containing the corresponding sequence of METTL3, miR‐21‐5p mimic or miR‐21‐5p inhibitor. We found that the levels of miR‐21‐5p and m⁶A modification in the UUO model groups increased significantly, and as predicted, the SPRY1/ERK/NF‐kB pathway was activated by miR‐21‐5p, confirming that miR‐21‐5p plays an important role in obstructive renal fibrosis by enhancing inflammation. METTL3 was found to play a major catalytic role in m⁶A modification in UUO mice and drove obstructive renal fibrosis development by promoting miR‐21‐5p maturation. Our research is the first to demonstrate the role of the METTL3‐m⁶A‐miR‐21‐5p‐SPRY1/ERK/NF‐kB axis in obstructive renal fibrosis and provides a deeper understanding of renal fibrosis.     

一种降低dATP用量的简单易错PCR方法

易错PCR是基因体外诱变的主要方法之一,是通过在PCR体系中添加Mn2+、提高Mg2+浓度和dCTP/dTTP浓度等措施达到基因诱变的目的。【目的和方法】本研究在不添加Mn2+、不调整其它任何PCR成分的情况下,通过降低dATP浓度的底物不平衡作用,对洋葱抗菌蛋白基因Ace-AMP1和苏云金芽胞杆菌毒蛋白(Bt)基因cry1A(c)进行了PCR诱变。【结果】结果表明:随着dATP浓度的降低,序列变异率和碱基突变率均呈升高趋势。当dTTP/dCTP/dGTP∶dATP在20∶1-40∶1时,碱基突变率介于1.4%-1.8%之间,序列变异率介于77.8%-100%之间。【讨论和结论】该方法简化了常规易错PCR诱变中的条件优化过程,简单实用。降低dATP浓度的诱变方法主要引起AT→GC的变异,适用于提高靶基因GC含量的体外诱变。本研究降低单一底物浓度的诱变方法可以提高诱变基因的AT或GC含量,是对易错PCR诱变方法的拓展。