MiR-140 protects against myocardial ischemia-reperfusion injury by regulating NF-κB pathway.

OBJECTIVE: The aim of this study was to investigate the effect of micro ribonucleic acid (miR)-140 on rats with myocardial ischemia-reperfusion injury (MIRI) through regulating the nuclear factor-κB (NF-κB) pathway. MATERIALS AND METHODS: A total of 36 Sprague-Dawley rats were randomly divided into three groups, including sham group (n=12), model group (n=12) and miR-140 mimics group (n=12). In sham group, only thoracotomy was performed without ischemia-reperfusion. In model group, the MIRI model was first established, followed by intervention using normal saline. In miR-140 mimics group, the MIRI model was first established as well, followed by intervention using miR-140 mimics. The content of serum creatine kinase (CK) and lactate dehydrogenase (LDH) was detected, and the morphology of myocardial tissues was observed via hematoxylin-eosin (HE) staining. Meanwhile, the relative protein expression of NF-κB was determined using Western blotting. Quantitative polymerase chain reaction (qPCR) was conducted to evaluate the expression of miR-140. The content of interleukin-1ß (IL-1ß) and tumor necrosis factor-α (TNF-α) was determined via enzyme-linked immunosorbent assay (ELISA). Furthermore, cell apoptosis was detected via terminal deoxynucleotidyl transferase-mediated dUTP nick end labeling (TUNEL) assay. RESULTS: The content of serum CK and LDH rose significantly in model group and miR-140 mimics group when compared with sham group (p<0.05). However, it declined significantly in miR-140 mimics group compared with model group (p<0.05). HE staining results showed that there were no obvious abnormalities in the morphology of myocardial tissues in sham group. However, there were injury and inflammatory infiltration in myocardial tissues in model group. Meanwhile, the structure and morphology of myocardial tissues were improved in miR-140 mimics group compared with those in model group. Western blotting revealed that the relative protein expression of NF-κB was evidently higher in model group and miR-140 mimics group than sham group (p<0.05). However, it was remarkably lower in miR-140 mimics group than that in model group (p<0.05). QPCR results demonstrated that the relative expression of miR-140 in model group and miR-140 mimics group was obviously lower than sham group (p<0.05). However, a markedly higher expression of miR-140 was observed in miR-140 mimics group than model group (p<0.05). ELISA results indicated that model group and miR-140 mimics group had remarkably higher content of IL-1ß and TNF-α than sham group (p<0.05). However, miR-140 mimics group had remarkably lower content of IL-1ß and TNF-α than model group (p<0.05). TUNEL assay indicated that the apoptosis rate increased obviously in model group and miR-140 mimics group compared with sham group (p<0.05). However, it declined significantly in miR-140 mimics group compared with model group (p<0.05). CONCLUSIONS: MiR-140 suppresses inflammation and apoptosis in myocardial tissues of MIRI rats through inhibiting the NF-κB signaling pathway, thereby exerting a cardioprotective effect.

Analysis of the cytochrome c oxidase subunit II (COX2) gene in giant panda, Ailuropoda melanoleuca.

The giant panda, Ailuropoda melanoleuca (Ursidae), has a unique bamboo-based diet; however, this low-energy intake has been sufficient to maintain the metabolic processes of this species since the fourth ice age. As mitochondria are the main sites for energy metabolism in animals, the protein-coding genes involved in mitochondrial respiratory chains, particularly cytochrome c oxidase subunit II (COX2), which is the rate-limiting enzyme in electron transfer, could play an important role in giant panda metabolism. Therefore, the present study aimed to isolate, sequence, and analyze the COX2 DNA from individuals kept at the Giant Panda Protection and Research Center, China, and compare these sequences with those of the other Ursidae family members. Multiple sequence alignment showed that the COX2 gene had three point mutations that defined three haplotypes, with 60% of the sequences corresponding to haplotype I. The neutrality tests revealed that the COX2 gene was conserved throughout evolution, and the maximum likelihood phylogenetic analysis, using homologous sequences from other Ursidae species, showed clustering of the COX2 sequences of giant pandas, suggesting that this gene evolved differently in them.

Optimal diversity-dependent contributions of genotypes to mixtures.

Deployment of genotypes to a production population decisively depends on the measure of diversity, a consideration that parallels genetic gain in the management of genotype mixtures. Optimal diversity-dependent deployment has been developed in this study for a family of diversity indices in the genetical and ecological context. The optimal solution at given diversity was expressed as the relationship between genotype contributions and their genetic performances, which maximized genetic gain. Numerical calculations were performed by using genotypes generated from normal order statistics. An optimal deployment in one situation could be nonoptimum in another. Classical uniform deployment, where superior genotypes equally contribute to the mixtures, was the limit of optimal deployment. Comparisons were made between optimal and uniform deployment and between optimal and nonoptimal deployment where genotypes contributed proportionally to the mixtures in accordance to their genetic superiority. The superiority in gain of optimal deployment over that of uniform deployment increased as the difference between the diversity measure under optimal deployment and the contributing number (N) of genotypes under uniform deployment became large and as the diversity measure and N under optimal deployment increased. The superiority over nonoptimal deployment increased rapidly at low diversity, reaching a maximum somewhere at diversity between 1 and N. Scale of superiority depended on the similitude between optimum and nonoptimum deployment; the larger the distinctiveness, the greater the superiority.

Expected gain and status number following restricted individual and combined-index selection.

Imposition of restrictions on number of individuals selected from a family and number of families from which superior individuals are selected could markedly alter the consequences of individual and combined-index selection. Predicted genetic gain and diversity measured as status number following selection were studied to draw general conclusions. Selection and its prediction were applied to two sets of real-life data. Theoretical prediction gave results close to those from factual selection. Gain and status number varied with initial family number and size, sib type, heritability, selection proportion, restriction type and intensity, and selection criteria. Proper restriction on the number of individuals selected can control the reduction of status number to an acceptable level, particularly when breeding values are used as the selection criterion. Restriction on the number of families selected would effectively improve the gain efficiency of selection based on phenotypic values. Choosing combinations of both restrictions might produce higher gain without the loss of status number. Given constant population size, family number should be large enough to ensure that restricted selection will yield higher gain and status number.

Response to selection with restrictions while considering effective family number.

Response to restricted selection (genetic gain) from unrelated families was studied as a function of effective family number. The restrictions applied were maximum limits on the number of families among which selections are allocated, or on the number of individuals selected from a family. Numerical results were calculated for large normally-distributed populations. Effects of different selection methods, selection intensities, restriction intensities, and heritability are demonstrated. Selection with restrictions is a handy alternative for tradeoff between gain and effective number. Restricted phenotypic selection seemed favourable when both gain and effective number are desirable. Optimal-index selection without restriction or with low intensity of restriction on the contributions of families was proposed to produce maximum gain if low effective number is tolerable. The conclusions were verified for a real material.

Optimal restricted phenotypic selection.

Phenotypic selection is modified by introducing upper limits on the portion (P 1) of individuals selected from a family as well as on the portion (P 2) of family number that are allowed to contribute. At a preset selection proportion, P and P 1, the maximum genetic gain is obtained by finding an optimum restriction on family number (P 2 (*) ). A numerical procedure for solving the problem of optimization is developed for infinite populations. In small populations, maximum gain and P 2 (*) can be found by simply comparing all possible P2. Numerical examples are demonstrated for infinite breeding populations, assuming a normally-distributed family mean and within-family deviation. Selection and its simulation were applied to the fieldtest results of two tree species. Optimum restriction on family number is very close to P/P 1, especially when heritability is low. In the real world of tree breeding, P 2 (*) is given, or approximated, by P/P 1+1/ tm where m is the initial family number. The improvement of gain and the conservation of inbreeding effective population size are easy with high heritability and could be simultaneously obtained by using intense selection with a relatively low P 1.

Effects of maternal environment on mortality and growth in young Pinus sylvestris in field trials.

The same full-sib families of Scots pine (Pinus sylvestris L.) were created by artificial pollination of genetically identical grafts at three localities in Sweden at approximately 56, 59 and 64 degrees N. Two field trials were established with one-year-old plants in different years at latitude 64 degrees N. Height and survival were monitored for 4-5 years following planting. Maternal environment had significant aftereffects on the height of progeny. In both field trials, plants with the maternal parent at 59 degrees N were tallest and plants with the maternal parent at 64 degrees N were shortest. The aftereffects of maternal environment were as large in six-year-old plants as in one-year-old plants. In one field trial, maternal environment had a significant effect on mortality six years after germination but not after three years. Mortality increased with decreasing latitude of the maternal location. We conclude that the aftereffects of maternal environment are too large and too permanent to be regarded as unimportant.