Genomic and phenotypic selection indices for decreased birth weight, shortening fattening period, and regulating total weight gain in beef cattle.

Objective: To develop genomic and phenotypic indices for beef cattle selection that afford progeny with reduced birth weight and fattening period. The indices should also allow regulating total weight gain during the fattening period and avoid marked increases of inbreeding. Methods: Whether addition of constraint on total weight gain to constraints on body weight gain at up to four specific time points during the fattening process was effective for the weight gain until the end of the fattening period was examined in two selection indices with the selection trait being a phenotypic or a genomic breeding value random regression coefficient. Results: Both indices afforded cattle with desired weight gains at specific time points and desired total weight gains. One cycle of index-based selection made it possible to shorten the fattening period two weeks compared with that before selection while maintaining the same final fattening weight as before selection. The impact of constraining total weight gain was smallest when the number of weight gain constraints at specific time points was three or four. However, constraining total weight gain was necessary to avoid poor total weight gain when the number of weight gain constraints at specific time points was only one or two. Conclusion: The developed indices make it possible to regulate total weight gain during the fattening process and to achieve desired weight gains at specific time points. Importantly, the indices bring about genetic improvement without an excessive increase of inbreeding. Thus, we expect that these indices will contribute to sustainable genetic improvement in cattle while maintaining genetic diversity.

Incorporating body measurement traits to increase genetic gain of feed efficiency and carcass traits in Japanese Black steers.

The objective of the present study was to comprehensively evaluate whether body measurement traits, including body weight and body size, could be used as indicators of genetic selection for feed efficiency and carcass traits in Japanese Black steers. First, we estimated the genetic parameters for body measurements, feed efficiency, and carcass traits. Second, we estimated the correlated responses in feed efficiency and carcass traits when selection was applied to one or multiple-body measurement traits. In total, 4,578 Japanese Black steers with phenotypic values of residual feed intake (RFI) and residual body weight gain (RG) as feed efficiency traits and carcass weight (CWT) and beef marbling standard (BMS) as carcass traits were used. Eleven body measurement traits were measured at the start and finish of the fattening periods (BMT1 and BMT2, respectively), and their growth during the fattening period (BMT3) was used for genetic analyses. The results of genetic parameters showed that the heritability estimates were low to moderate (0.10 to 0.66), and the genetic correlations among body measurement traits were also estimated to be positively moderate to high in each measuring point (0.23 to 0.99). The genetic correlations of body measurement traits with RFI and BMS were estimated to be low (-0.14 to 0.30 and -0.17 to 0.35, respectively), but those with CWT were positively low to high (0.12 to 0.97). The genetic correlation estimates between BMT3 and RG were moderate to high (0.38 to 0.78). Second, correlated responses were estimated under positive selection for body measurement traits. Positive selection for BMT2 and BMT3 increased CWT and RG; however, positive selection for body measurement traits resulted in no change in RFI and BMS. Favorable directions of genetic gains, which were positive for RG, CWT, and BMS and negative for RFI, were obtained by selection indices, including multiple traits in BMT1. Our results suggest that using only one-body measurement trait as an indicator of genetic selection for RFI is difficult. However, body measurement traits can be indirect indicators of improved RG. Our results also suggest that genetic improvement of both RFI and RG without reducing CWT and BMS could be achieved using selection indices that account for a balance of body conformation using multiple-body measurement traits in Japanese Black cattle.

Improving feed efficiency is a key objective in the beef cattle industry. Still, high costs and logistical efforts make measuring daily feed intake per animal in many cattle difficult. Here, we focused on body measurement traits, including body weight and body size, as indirect indicators of feed efficiency in Japanese Black cattle, as measuring these traits is easy and inexpensive. When selection was applied to one- or multiple-body measurement traits, we estimated the correlated responses in feed efficiency and carcass traits. We also estimated the genetic relationships of body measurement traits with feed efficiency and carcass traits. Our results showed body measurement traits were heritable and had weak genetic relationships with residual feed intake. Regarding the possibility of genetic selection for residual feed intake using body measurement traits as indirect indicators, our results suggest that using a single body measurement trait as an indicator is difficult. However, our results also suggest that the genetic improvement of residual feed intake could be possible using selection indices that account for a balance of body conformation using multiple-body measurement traits in Japanese Black cattle.

Development of an index that decreases birth weight, promotes postnatal growth and yet minimizes selection intensity in beef cattle.

OBJECTIVE: The main goal of our current study was to improve the growth curve of meat animals by decreasing the birth weight while achieving a finishing weight that is the same as that before selection but at younger age. METHODS: Random regression model was developed to derive various selection indices to achieve desired gains in body weight at target time points throughout the fattening process. We considered absolute and proportional gains at specific ages (in weeks) and for various stages (i.e., early, middle, late) during the fattening process. RESULTS: The point gain index was particularly easy to use because breeders can assign a specific age (in weeks) as a time point and model either the actual weight gain desired or a scaled percentage gain in body weight. CONCLUSION: The point gain index we developed can achieve the desired weight gain at any given postnatal week of the growing process and is an easy-to-use and practical option for improving the growth curve.

Genomic dissection of repeatability considering additive and nonadditive genetic effects for semen production traits in beef and dairy bulls.

The low heritability and moderate repeatability of semen production traits in beef and dairy bulls suggest that nonadditive genetic effects, such as dominance and epistatic effects, play an important role in semen production and should therefore be considered in genetic improvement programs. In this study, the repeatability of semen production traits in Japanese Black bulls (JB) as beef bulls and Holstein bulls (HOL) as dairy bulls was evaluated by considering additive and nonadditive genetic effects using the Illumina BovineSNP50 BeadChip. We also evaluated the advantage of using more complete models that include nonadditive genetic effects by comparing the rank of genotyped animals and the phenotype prediction ability of each model. In total, 65,463 records for 615 genotyped JB and 48,653 records for 845 genotyped HOL were used to estimate additive and nonadditive (dominance and epistatic) variance components for semen volume (VOL), sperm concentration (CON), sperm motility (MOT), MOT after freeze-thawing (aMOT), and sperm number (NUM). In the model including both additive and nonadditive genetic effects, the broad-sense heritability (0.17 to 0.43) was more than twice as high as the narrow-sense heritability (0.04 to 0.11) for all traits and breeds, and the differences between the broad-sense heritability and repeatability were very small for VOL, NUM, and CON in both breeds. A large proportion of permanent environmental variance was explained by epistatic variance. The epistatic variance as a proportion of total phenotypic variance was 0.07 to 0.33 for all traits and breeds. In addition, heterozygosity showed significant positive relationships with NUM, MOT, and aMOT in JB and NUM in HOL, when the heterozygosity rate was included as a covariate. In a comparison of models, the inclusion of nonadditive genetic effects resulted in a re-ranking of the top genotyped bulls for the additive effects. Adjusting for nonadditive genetic effects could be expected to produce a more accurate breeding value, even if the models have similar fitting. However, including nonadditive genetic effects did not improve the ability of any model to predict phenotypic values for any trait or breed compared with the predictive ability of a model that includes only additive effects. Consequently, although nonadditive genetic effects, especially epistatic effects, play an important role in semen production traits, they do not improve prediction accuracy in beef and dairy bulls.

Improving reproductive efficiency is a key objective in the beef and dairy cattle industries, and bull fertility is an important determinant of the reproductive performance of cows. The heritability of semen production traits is generally low; however, their repeatability is moderate. This difference between repeatability and heritability suggests that nonadditive genetic effects, such as dominance and epistatic genetic effects, could have an important role in semen production traits in bulls. Here, we estimated repeatability for semen production traits in beef and dairy bulls by considering additive and nonadditive genetic effects. Our results suggest that the contribution of nonadditive genetic effects to differences between repeatability and heritability was very high. Nonadditive genetic effects, especially epistatic effects, played important roles in semen production traits in beef and dairy bulls. However, we found that the inclusion of nonadditive genetic effects in a predictive model does not improve phenotypic prediction accuracy; further studies are needed to improve the predictive ability when using nonadditive genetic effects.

Genomic prediction with non-additive effects in beef cattle: stability of variance component and genetic effect estimates against population size.

BACKGROUND: Genomic prediction is now an essential technology for genetic improvement in animal and plant breeding. Whereas emphasis has been placed on predicting the breeding values, the prediction of non-additive genetic effects has also been of interest. In this study, we assessed the potential of genomic prediction using non-additive effects for phenotypic prediction in Japanese Black, a beef cattle breed. In addition, we examined the stability of variance component and genetic effect estimates against population size by subsampling with different sample sizes. RESULTS: Records of six carcass traits, namely, carcass weight, rib eye area, rib thickness, subcutaneous fat thickness, yield rate and beef marbling score, for 9850 animals were used for analyses. As the non-additive genetic effects, dominance, additive-by-additive, additive-by-dominance and dominance-by-dominance effects were considered. The covariance structures of these genetic effects were defined using genome-wide SNPs. Using single-trait animal models with different combinations of genetic effects, it was found that 12.6-19.5 % of phenotypic variance were occupied by the additive-by-additive variance, whereas little dominance variance was observed. In cross-validation, adding the additive-by-additive effects had little influence on predictive accuracy and bias. Subsampling analyses showed that estimation of the additive-by-additive effects was highly variable when phenotypes were not available. On the other hand, the estimates of the additive-by-additive variance components were less affected by reduction of the population size. CONCLUSIONS: The six carcass traits of Japanese Black cattle showed moderate or relatively high levels of additive-by-additive variance components, although incorporating the additive-by-additive effects did not improve the predictive accuracy. Subsampling analysis suggested that estimation of the additive-by-additive effects was highly reliant on the phenotypic values of the animals to be estimated, as supported by low off-diagonal values of the relationship matrix. On the other hand, estimates of the additive-by-additive variance components were relatively stable against reduction of the population size compared with the estimates of the corresponding genetic effects.

Identification of deleterious recessive haplotypes and candidate deleterious recessive mutations in Japanese Black cattle.

Intensive use of a few elite sires has increased the risk of the manifestation of deleterious recessive traits in cattle. Substantial genotyping data gathered using single-nucleotide polymorphism (SNP) arrays have identified the haplotypes with homozygous deficiency, which may compromise survival. We developed Japanese Black cattle haplotypes (JBHs) using SNP array data (4843 individuals) and identified deleterious recessive haplotypes using exome sequencing of 517 sires. We identified seven JBHs with homozygous deficiency. JBH_10 and JBH_17 were associated with the resuming of estrus after artificial insemination, indicating that these haplotypes carried deleterious mutations affecting embryonic survival. The exome data of 517 Japanese Black sires revealed that AC_000165.1:g.85341291C>G of IARS in JBH_8_2, AC_000174.1:g.74743512G>T of CDC45 in JBH_17, and a copy variation region (CNVR_27) of CLDN16 in JBH_1_1 and JBH_1_2 were the candidate mutations. A novel variant AC_000174.1:g.74743512G>T of CDC45 in JBH_17 was located in a splicing donor site at a distance of 5 bp, affecting pre-mRNA splicing. Mating between heterozygotes of JBH_17 indicated that homozygotes carrying the risk allele died around the blastocyst stage. Analysis of frequency of the CDC45 risk allele revealed that its carriers were widespread throughout the tested Japanese Black cattle population. Our approach can effectively manage the inheritance of recessive risk alleles in a breeding population.

Development of a structural growth curve model that considers the causal effect of initial phenotypes.

BACKGROUND: Growth curves have been widely used in genetic analyses to gain insights into the growth characteristics of both animals and plants. However, several questions remain unanswered, including how the initial phenotypes affect growth and what is the duration of any such impact. For beef cattle production in Japan, calves are procured from farms that specialize in reproduction and then moved to other farms where they are fattened to achieve their market/purchase value. However, the causal effect of growth, while calves are on the reproductive farms, on their growth during fattening remains unclear. To investigate this, we developed a model that combines a structural equation with a growth curve model. The causal effect was modeled with B-splines, which allows inference of the effect as a curve. We fitted the proposed structural growth curve model to repeated measures of body weight from a Japanese beef cattle population (n = 3831) to estimate the curve of the causal effect of the calves' initial weight on their trajectory of growth when they are on fattening farms. RESULTS: Maternal and reproduction farm effects explained 26% of the phenotypic variance of initial weight at fattening farms. The structural growth curve model was fitted to remove the effects of these factors in growth curve analysis at fattening farms. The estimated curve of causal effects remained at approximately 0.8 for 200 d after the calves entered the fattening farms, which means that 64% of the phenotypic variance was explained by the initial weight. Then, the effect decreased linearly and disappeared approximately 620 d after entering the fattening farms, which corresponded to an average age of 871.5 d. CONCLUSIONS: The proposed model is expected to provide more accurate estimates of genetic values for growth patterns because the confounding causal factors such as maternal and reproduction farm effects are removed. Moreover, examination of the inferred curve of the causal effect enabled us to estimate the effect of a calf's initial weight at arbitrary times during growth, which could provide suitable information for decision-making when shifting the time of slaughter, building models for genetic evaluation, and selecting calves for market.

Effects of preselection of genotyped animals on reliability and bias of genomic prediction in dairy cattle.

OBJECTIVE: Models for genomic selection assume that the reference population is an unselected population. However, in practice, genotyped individuals, such as progeny-tested bulls, are highly selected, and the reference population is created after preselection. In dairy cattle, the intensity of selection is higher in males than in females, suggesting that cows can be added to the reference population with less bias and loss of accuracy. The objective is to develop formulas applied to any genomic prediction studies or practice with preselected animals as reference population. METHODS: We developed formulas for calculating the reliability and bias of genomically enhanced breeding values (GEBV) in the reference population where individuals are preselected on estimated breeding values. Based on the formulas presented, deterministic simulation was conducted by varying heritability, preselection percentage, and the reference population size. RESULTS: The number of bulls equal to a cow regarding the reliability of GEBV was expressed through a simple formula for the reference population consisting of preselected animals. The bull population was vastly superior to the cow population regarding the reliability of GEBV for low-heritability traits. However, the superiority of reliability from the bull reference population over the cow population decreased as heritability increased. Bias was greater for bulls than cows. Bias and reduction in reliability of GEBV due to preselection was alleviated by expanding reference population. CONCLUSION: Cows are easier in expanding reference population size compared with bulls and alleviate bias and reduction in reliability of GEBV of bulls which are highly preselected than cows by expanding the cow reference population.

Evaluation of feed efficiency traits for genetic improvement in Japanese Black cattle.

We evaluated the genetic relationships (1) among feed efficiency traits with different fattening periods, (2) between feed efficiency traits and growth traits, and (3) between feed efficiency traits and carcass traits, to determine the influence of genetic factors on feed efficiency traits. In total, 4,578 Japanese Black cattle from a progeny testing program were used. Residual feed intake (RFI), residual BW gain (RG), and residual intake and BW gain (RIG) were defined as feed efficiency traits, and were measured for the first half (approximately 9 to 15 months of age), latter half (approximately 15 to 21 months of age), and total period of fattening (approximately 9 to 21 months of age). A single-trait animal model for estimating heritability and a two-trait animal model for estimating genetic and phenotypic correlations were used. The heritability estimates for RFI, RG, and RIG were different in each fattening period, ranging from 0.36 to 0.46, 0.19 to 0.28, and 0.28 to 0.34, respectively, and the heritability estimates for the total fattening period were greater than those for the first and latter halves separately. RIG showed the greatest preferred genetic correlation, with a greater feed conversion ratio than the other feed efficiency traits (ranging from -0.84 to -0.96). RG in the first and latter halves of the fattening period had different genetic correlations with the growth starting point (0.82 and -0.06, respectively) and maturity rate (0.49 and -0.51, respectively) of the Gompertz growth curve parameters, and is strongly dependent on the different fattening periods. Feed efficiency traits in different fattening periods had low genetic correlations with the carcass traits (from -0.05 to 0.19 for RFI; from 0.02 to 0.31 for RG; and from -0.11 to 0.20 for RIG). This study indicated the possibility for genetic improvement through the selection of high-RIG animals to decrease feed intake and increase BW gain without any unfavorable correlated responses affecting mature (asymptotic) weight and carcass grade.

Lineage-specific gene acquisition or loss is involved in interspecific hybrid sterility in rice.

Understanding the genetic basis of reproductive barriers between species has been a central issue in evolutionary biology. The S1 locus in rice causes hybrid sterility and is a major reproductive barrier between two rice species, Oryza sativa and Oryza glaberrima The O. glaberrima-derived allele (denoted S1g) on the S1 locus causes preferential abortion of gametes with its allelic alternative (denoted S1s) in S1g/S1s heterozygotes. Here, we used mutagenesis and screening of fertile hybrid plants to isolate a mutant with an allele, S1mut, which does not confer sterility in the S1mut/S1g and S1mut/S1s hybrids. We found that the causal mutation of the S1mut allele was a deletion in the peptidase-coding gene (denoted "SSP") in the S1 locus of O. glaberrima No orthologous genes of SSP were found in the O. sativa genome. Transformation experiments indicated that the introduction of SSP in carriers of the S1s allele did not induce sterility. In S1mut/S1s heterozygotes, the insertion of SSP led to sterility, suggesting that SSP complemented the loss of the functional phenotype of the mutant and that multiple factors are involved in the phenomenon. The polymorphisms caused by the lineage-specific acquisition or loss of the SSP gene were implicated in the generation of hybrid sterility. Our results demonstrated that artificial disruption of a single gene for the reproductive barrier creates a "neutral" allele, which facilitates interspecific hybridization for breeding programs.

Autophagic adaptations in diabetic cardiomyopathy differ between type 1 and type 2 diabetes.

Little is known about the association between autophagy and diabetic cardiomyopathy. Also unknown are possible distinguishing features of cardiac autophagy in type 1 and type 2 diabetes. In hearts from streptozotocin-induced type 1 diabetic mice, diastolic function was impaired, though autophagic activity was significantly increased, as evidenced by increases in microtubule-associated protein 1 light chain 3/LC3 and LC3-II/-I ratios, SQSTM1/p62 (sequestosome 1) and CTSD (cathepsin D), and by the abundance of autophagic vacuoles and lysosomes detected electron-microscopically. AMP-activated protein kinase (AMPK) was activated and ATP content was reduced in type 1 diabetic hearts. Treatment with chloroquine, an autophagy inhibitor, worsened cardiac performance in type 1 diabetes. In addition, hearts from db/db type 2 diabetic model mice exhibited poorer diastolic function than control hearts from db/+ mice. However, levels of LC3-II, SQSTM1 and phosphorylated MTOR (mechanistic target of rapamycin) were increased, but CTSD was decreased and very few lysosomes were detected ultrastructurally, despite the abundance of autophagic vacuoles. AMPK activity was suppressed and ATP content was reduced in type 2 diabetic hearts. These findings suggest the autophagic process is suppressed at the final digestion step in type 2 diabetic hearts. Resveratrol, an autophagy enhancer, mitigated diastolic dysfunction, while chloroquine had the opposite effects in type 2 diabetic hearts. Autophagy in the heart is enhanced in type 1 diabetes, but is suppressed in type 2 diabetes. This difference provides important insight into the pathophysiology of diabetic cardiomyopathy, which is essential for the development of new treatment strategies.

OPC-28326, a selective peripheral vasodilator with angiogenic activity, mitigates postinfarction cardiac remodeling.

Although OPC-28326, 4-(N-methyl-2-phenylethylamino)-1-(3,5-dimethyl-4-propionyl-aminobenzoyl) piperidine hydrochloride monohydrate, was developed as a selective peripheral vasodilator with α2-adrenergic antagonist properties, it also reportedly exhibits angiogenic activity in an ischemic leg model. The purpose of this study was to examine the effect of OPC-28326 on the architectural dynamics and function of the infarcted left ventricle during the chronic stage of myocardial infarction. Myocardial infarction was induced in male C3H/He mice, after which the mice were randomly assigned into two groups: a control group receiving a normal diet and an OPC group whose diet contained 0.05% OPC-28326. The survival rate among the mice (n = 18 in each group) 4 wk postinfarction was significantly greater in the OPC than control group (83 vs. 44%; P < 0.05), and left ventricular remodeling and dysfunction were significantly mitigated. Histologically, infarct wall thickness was significantly greater in the OPC group, due in part to an abundance of nonmyocyte components, including blood vessels and myofibroblasts. Five days postinfarction, Ki-67-positive proliferating cells were more abundant in the granulation tissue in the OPC group, and there were fewer apoptotic cells. These effects were accompanied by activation of myocardial Akt and endothelial nitric oxide synthase. Hypoxia within the infarct issue, assessed using pimonidazole staining, was markedly attenuated in the OPC group. In summary, OPC-28326 increased the nonmyocyte population in infarct tissue by increasing proliferation and reducing apoptosis, thereby altering the tissue dynamics such that wall stress was reduced, which might have contributed to a mitigation of postinfarction cardiac remodeling and dysfunction.

Restriction of food intake prevents postinfarction heart failure by enhancing autophagy in the surviving cardiomyocytes.

We investigated the effect of restriction of food intake, a potent inducer of autophagy, on postinfarction cardiac remodeling and dysfunction. Myocardial infarction was induced in mice by left coronary artery ligation. At 1 week after infarction, mice were randomly divided into four groups: the control group was fed ad libitum (100%); the food restriction (FR) groups were fed 80%, 60%, or 40% of the mean amount of food consumed by the control mice. After 2 weeks on the respective diets, left ventricular dilatation and hypofunction were apparent in the control group, but both parameters were significantly mitigated in the FR groups, with the 60% FR group showing the strongest therapeutic effect. Cardiomyocyte autophagy was strongly activated in the FR groups, as indicated by up-regulation of microtubule-associated protein 1 light chain 3-II, autophagosome formation, and myocardial ATP content. Chloroquine, an autophagy inhibitor, completely canceled the therapeutic effect of FR. This negative effect was associated with reduced activation of AMP-activated protein kinase and of ULK1 (a homolog of yeast Atg1), both of which were enhanced in hearts from the FR group. In vitro, the AMP-activated protein kinase inhibitor compound C suppressed glucose depletion-induced autophagy in cardiomyocytes, but did not influence activity of chloroquine. Our findings imply that a dietary protocol with FR could be a preventive strategy against postinfarction heart failure.

Resveratrol reverses remodeling in hearts with large, old myocardial infarctions through enhanced autophagy-activating AMP kinase pathway.

We investigated the effect of resveratrol, a popular natural polyphenolic compound with antioxidant and proautophagic actions, on postinfarction heart failure. Myocardial infarction was induced in mice by left coronary artery ligation. Four weeks postinfarction, when heart failure was established, the surviving mice were started on 2-week treatments with one of the following: vehicle, low- or high-dose resveratrol (5 or 50 mg/kg/day, respectively), chloroquine (an autophagy inhibitor), or high-dose resveratrol plus chloroquine. High-dose resveratrol partially reversed left ventricular dilation (reverse remodeling) and significantly improved cardiac function. Autophagy was augmented in those hearts, as indicated by up-regulation of myocardial microtubule-associated protein-1 light chain 3-II, ATP content, and autophagic vacuoles. The activities of AMP-activated protein kinase and silent information regulator-1 were enhanced in hearts treated with resveratrol, whereas Akt activity and manganese superoxide dismutase expression were unchanged, and the activities of mammalian target of rapamycin and p70 S6 kinase were suppressed. Chloroquine elicited opposite results, including exacerbation of cardiac remodeling associated with a reduction in autophagic activity. When resveratrol and chloroquine were administered together, the effects offset one another. In vitro, compound C (AMP-activated protein kinase inhibitor) suppressed resveratrol-induced autophagy in cardiomyocytes, but did not affect the events evoked by chloroquine. In conclusion, resveratrol is a beneficial pharmacological tool that augments autophagy to bring about reverse remodeling in the postinfarction heart.

Application of highly differentiated SNPs between Japanese Black and Holstein to a breed assignment test between Japanese Black and F(1) (Japanese Black x Holstein) and Holstein.

Two taurine breeds, Japanese Black and Holstein, established from geographically distant origins and selected for different uses, beef and dairy, were extensively genotyped using a genome-wide single nucleotide polymorphism (SNP) chip with more than 1000 animals of each breed. The genetic structure was examined by principal component analysis, in which the first principal component clearly separated the two breeds and explained more than 15% of the variance. Highly differentiated SNPs were detected throughout the genome, some of which were clustered within small regions on BTA4 (79.2-79.7 Mb, Btau4.0) and BTA26 (22.2-23.6 Mb). A breed assignment test was developed using 18 highly differentiated SNPs to distinguish Japanese Black from F(1) (Japanese Black × Holstein) and Holstein. The error rate that an F(1) or Holstein animal is misjudged as Japanese Black was expected to be < 0.8%, while the error rate that a Japanese Black animal is misjudged as F(1) or Holstein was expected to be < 0.001%. This test provides a reliable and powerful method to detect breed label falsification in retail beef.

Prior starvation mitigates acute doxorubicin cardiotoxicity through restoration of autophagy in affected cardiomyocytes.

AIMS: Active autophagy has recently been reported in doxorubicin-induced cardiotoxicity; here we investigated its pathophysiological role. METHODS AND RESULTS: Acute cardiotoxicity was induced in green fluorescent protein-microtubule-associated protein 1 light chain 3 (GFP-LC3) transgenic mice by administering two intraperitoneal injections of 10 mg/kg doxorubicin with a 3 day interval. A starvation group was deprived of food for 48 h before each injection to induce autophagy in advance. Doxorubicin treatment caused left ventricular dilatation and dysfunction within 6 days. Cardiomyocyte autophagy appeared to be activated in the doxorubicin group, based on LC3, p62, and cathepsin D expression, while it seemed somewhat diminished by starvation prior to doxorubicin treatment. Unexpectedly, however, myocardial ATP levels were reduced in the doxorubicin group, and this reduction was prevented by earlier starvation. Electron microscopy revealed that the autophagic process was indeed initiated in the doxorubicin group, as shown by the increased lysosomes, but was not completed, i.e. autophagolysosome formation was rare. Starvation prior to doxorubicin treatment partly restored autophagosome formation towards control levels. Autophagic flux assays in both in vivo and in vitro models confirmed that doxorubicin impairs completion of the autophagic process in cardiomyocytes. The activities of both AMP-activated protein kinase and the autophagy-initiating kinase unc-51-like kinase 1 (ULK1) were found to be decreased by doxorubicin, and these were restored by prior starvation. CONCLUSION: Prior starvation mitigates acute doxorubicin cardiotoxicity; the underlying mechanism may be, at least in part, restoration and further augmentation of myocardial autophagy, which is impaired by doxorubicin, probably through inactivation of AMP-activated protein kinase and ULK1.

Asialoerythropoietin, a nonerythropoietic derivative of erythropoietin, displays broad anti-heart failure activity.

BACKGROUND: We investigated the effects of asialoerythropoietin (asialoEPO), a nonerythrogenic erythropoietin derivative, on 3 murine models of heart failure with different etiologies. METHODS AND RESULTS: Doxorubicin (15 mg/kg) induced heart failure within 2 weeks (toxic cardiomyopathy). Treatment with asialoEPO (6.9 µg/kg) for 2 weeks thereafter attenuated the associated left ventricular dysfunction and dilatation. In addition, the asialoEPO-treated heart showed less myocardial fibrosis, inflammation, and oxidative damage, and diminished atrophic cardiomyocyte degeneration, which was accompanied by restored expression of GATA-4 and sarcomeric proteins. Mice with large 6-week-old myocardial infarctions exhibited marked left ventricular dysfunction with adverse remodeling (ischemic cardiomyopathy). AsialoEPO treatment for 4 weeks significantly mitigated progression of the dysfunction and remodeling and reduced myocardial fibrosis, inflammation, and oxidative damage. Finally, 25-week-old δ-sarcoglycan-deficient mice (genetic cardiomyopathy) were treated with asialoEPO for 5 weeks. AsialoEPO mitigated the progressive cardiac remodeling and dysfunction through cardiomyocyte hypertrophy, and upregulated expression of GATA-4 and sarcomeric proteins. AsialoEPO appears to act by altering the activity of the downstream erythropoietin receptor signals extracellular signal-regulated protein kinase, Akt, signal transducer, and activator of transcription 3 and 5 in a model-specific manner. CONCLUSIONS: The findings suggest that asialoEPO exerts broad cardioprotective effects through distinct mechanisms depending on the model, which are independent of the erythrogenic action. This compound may be promising for the treatment of heart failure of various etiologies.

Differentiation in wild-type allele of the sd1 locus concerning culm length between indica and japonica subspecies of Oryza sativa (rice).

A dwarfing gene (allele) sd1-d has been intensively utilized to develop short-culm indica varieties in southeast Asia up to now. Before the first sd1-d-carrying variety IR8 was released, rice researchers had recognized the general tendency that culm length is higher in indica varieties than in temperate-japonica ones. Inter-subspecific difference of the tall (wild-type) allele SD1 at the sd1 locus was examined on the common genetic background, using five isogenic lines developed by substituting sd1-d of the recurrent parent IR36 by SD1s of two indica varieties, two temperate-japonica varieties and one tropical-japonica variety. The two indica -donor isogenic lines had longer culms than the three japonica-donor isogenic lines consistently in two different environmental conditions. Moreover, nonsynonymous single-nucleotide polymorphism between the two subspecies was detected at two sites in Exon 1 and Exon 3 of the sd1 locus. It is demonstrated that the inter-subspecific differentiation of SD1 contributes height difference between indica and japonica. The indica-originating and japonica-originating alleles at the sd1 locus were designated as SD1-in(t) and SD1-ja(t), respectively.

A novel mutation of the bovine EDA gene associated with anhidrotic ectodermal dysplasia in Holstein cattle.

Anhidrotic ectodermal dysplasia (EDA) is a genetic disease characterized by the absence or hypoplasia of hair, teeth and eccrine sweat glands that has been reported in humans, the tabby mouse mutants, cattle and dogs. The EDA gene on the X chromosome encodes a protein, ectodysplasin-A (EDA), which is responsible for EDA. Here we describe a novel mutation of the EDA gene in which a 19 bp deletion in exon 1 in male Holstein calves demonstrated the phenotypic features of EDA. The dam and the grand-dam of the affected calves were heterozygous for this deletion. It is assumed that this deletion close to the start codon confuses all transcripts, and leads to the complete loss of pleiotropic functions of the bovine EDA gene. These results suggest that this mutation might be useful as animal models for the investigation of the pathogenic mechanisms of the anhidrotic ectodermal dysplasia.

The role of autophagy emerging in postinfarction cardiac remodelling.

AIMS: Autophagy is activated in cardiomyocytes in ischaemic heart disease, but its dynamics and functional roles remain unclear after myocardial infarction. We observed the dynamics of cardiomyocyte autophagy and examined its role during postinfarction cardiac remodelling. METHODS AND RESULTS: Myocardial infarction was induced in mice by ligating the left coronary artery. During both the subacute and chronic stages (1 and 3 weeks postinfarction, respectively), autophagy was found to be activated in surviving cardiomyocytes, as demonstrated by the up-regulated expression of microtubule-associated protein-1 light chain 3-II (LC3-II), p62 and cathepsin D, and by electron microscopic findings. Activation of autophagy, specifically the digestion step, was prominent in cardiomyocytes 1 week postinfarction, especially in those bordering the infarct area, while the formation of autophagosomes was prominent 3 weeks postinfarction. Bafilomycin A1 (an autophagy inhibitor) significantly aggravated postinfarction cardiac dysfunction and remodelling. Cardiac hypertrophy was exacerbated in this group and was accompanied by augmented ventricular expression of atrial natriuretic peptide. In these hearts, autophagic findings (i.e. expression of LC3-II and the presence of autophagosomes) were diminished, and activation of AMP-activated protein kinase was enhanced. Treatment with rapamycin (an autophagy enhancer) brought about opposite outcomes, including mitigation of cardiac dysfunction and adverse remodelling. A combined treatment with bafilomycin A1 and rapamycin offset each effect on cardiomyocyte autophagy and cardiac remodelling in the postinfarction heart. CONCLUSION: These findings suggest that cardiomyocyte autophagy is an innate mechanism that protects against progression of postinfarction cardiac remodelling, implying that augmenting autophagy could be a therapeutic strategy.