Uncoupling Protein 2 Alleviates Myocardial Ischemia/Reperfusion Injury by Inhibiting Cardiomyocyte Ferroptosis.

INTRODUCTION: Following our recent finding that Ucp2 knockout promotes ferroptosis, we aimed to examine whether UCP2 alleviates myocardial ischemia/reperfusion injury (MI/RI) by inhibiting ferroptosis. METHODS: The left anterior descending coronary arteries of wild-type and Ucp2-/- C57BL/6 mice were ligated for 30 min and reperfused for 2 h to establish an MI/RI model. The effects of UCP2 on ferroptosis and MI/RI were determined by echocardiography, 2,3,5-triphenylttrazolium chloride staining, hematoxylin-eosin staining, Masson's trichrome staining, Sirius red staining, and analysis of myocardial injury markers and ferroptosis indicators. Ferrostatin-1 (Fer-1) and erastin (Era) were used to investigate whether UCP2 alleviated MI/RI by inhibiting ferroptosis and the molecular mechanism. RESULTS: UCP2 was upregulated in the MI/RI model in WT mice. Deletion of Ucp2 exacerbated ferroptosis, altered the expression levels of multiple ferroptosis-related genes, and significantly exacerbated MI/RI. Knockout of Ucp2 promoted ferroptosis induced by Era and inhibited the antiferroptotic effects of Fer-1. Knockout of Ucp2 activated the p53/TfR1 pathway to exacerbate ferroptosis. CONCLUSION: Our results showed that UCP2 inhibited ferroptosis in MI/RI, which might be related to regulation of the p53/TfR1 pathway.

Emodin ameliorates myocardial fibrosis in mice by inactivating the ROS/PI3K/Akt/mTOR axis.

BACKGROUND: Emodin is a traditional medicine that has been shown to exert anti-inflammatory and anti-oxidative effects. Previous research has indicated that emodin can alleviate myocardial remodeling and inhibit myocardial hypertrophy and fibrosis. However, the mechanism by which emodin affects myocardial fibrosis (MF) has not yet been elucidated. METHODS: Fibroblasts were treated with ANGII, and a mouse model of MF was established by ligation of the left anterior descending coronary artery. Cell proliferation was examined by a Cell Counting Kit-8 (CCK8) assay. Dihydroethidium (DHE) was used to measure reactive oxygen species (ROS) levels, and Masson and Sirius red staining were used to examine changes in collagen fiber levels. PI3K was over-expressed by lentiviral transfection to verify the effect of emodin on the PI3K/AKT/mTOR signaling axis. Changes in cardiac function in each group were examined by echocardiography. RESULTS: Emodin significantly inhibited fibroblast proliferation, decreased intracellular ROS levels, significantly upregulated collagen II expression, downregulated α-SMA expression, and inhibited PI3K/AKT/mTOR pathway activation in vitro. Moreover, the in vivo results were consistent with the in vitro. Emodin significantly decreased ROS levels in heart tissue and reduced collagen fibrillogenesis. Emodin could regulate the activity of PI3K to increase the expression of collagen II and downregulate α-SMA expression in part through the PI3K/AKT/mTOR pathway, and emodin significantly improved cardiac structure and function in mice. CONCLUSIONS: This study revealed that emodin targeted the PI3K/AKT/mTOR pathway to inhibit the development of myocardial fibrosis and may be an antifibrotic agent for the treatment of cardiac fibrosis.

Wheat NAC-A18 regulates grain starch and storage proteins synthesis and affects grain weight.

KEY MESSAGE: Wheat NAC-A18 regulates both starch and storage protein synthesis in the grain, and a haplotype with positive effects on grain weight showed increased frequency during wheat breeding in China. Starch and seed storage protein (SSP) directly affect the processing quality of wheat grain. The synthesis of starch and SSP are also regulated at the transcriptional level. However, only a few starch and SSP regulators have been identified in wheat. In this study, we discovered a NAC transcription factor, designated as NAC-A18, which acts as a regulator of both starch and SSP synthesis. NAC-A18, is predominately expressed in wheat developing grains, encodes a transcription factor localized in the nucleus, with both activation and repression domains. Ectopic expression of wheat NAC-A18 in rice significantly decreased starch accumulation and increased SSP accumulation and grain size and weight. Dual-luciferase reporter assays indicated that NAC-A18 could reduce the expression of TaGBSSI-A1 and TaGBSSI-A2, and enhance the expression of TaLMW-D6 and TaLMW-D1. A yeast one hybrid assay demonstrated that NAC-A18 bound directly to the cis-element "ACGCAA" in the promoters of TaLMW-D6 and TaLMW-D1. Further analysis indicated that two haplotypes were formed at NAC-A18, and that NAC-A18_h1 was a favorable haplotype correlated with higher thousand grain weight. Based on limited population data, NAC-A18_h1 underwent positive selection during Chinese wheat breeding. Our study demonstrates that wheat NAC-A18 regulates starch and SSP accumulation and grain size. A molecular marker was developed for the favorable allele for breeding applications.

TabHLH95-TaNF-YB1 module promotes grain starch synthesis in bread wheat.

Starch is the most abundant substance in wheat (Triticum aestivum L.) endosperm and provides the major carbohydrate energy for human daily life. Starch synthesis-related (SSR) genes are believed to be spatiotemporally specific, but their transcriptional regulation remains unclear in wheat. Here, we investigate the role of the basic helix-loop-helix (bHLH) transcription factor TabHLH95 in starch synthesis. TabHLH95 is preferentially expressed in the developing grains in wheat and encodes a nucleus localized protein without autoactivation activity. The Tabhlh95 knockout mutants display smaller grain size and less starch content than wild type, whereas overexpression of TabHLH95 enhances starch accumulation and significantly improves thousand grain weight. Transcriptome analysis reveals that the expression of multiple SSR genes is significantly reduced in the Tabhlh95 mutants. TabHLH95 binds to the promoters of ADP-glucose pyrophosphorylase large subunit 1 (AGPL1-1D/-1B), AGPL2-5D, and isoamylase (ISA1-7D) and enhances their transcription. Intriguingly, TabHLH95 interacts with the nuclear factor Y (NF-Y) family transcription factor TaNF-YB1, thereby synergistically regulating starch synthesis. These results suggest that the TabHLH95-TaNF-YB1 complex positively modulates starch synthesis and grain weight by regulating the expression of a subset of SSR genes, thus providing a good potential approach for genetic improvement of grain productivity in wheat.

TaTPP-7A positively feedback regulates grain filling and wheat grain yield through T6P-SnRK1 signalling pathway and sugar-ABA interaction.

Grain size and filling are two key determinants of grain thousand-kernel weight (TKW) and crop yield, therefore they have undergone strong selection since cereal was domesticated. Genetic dissection of the two traits will improve yield potential in crops. A quantitative trait locus significantly associated with wheat grain TKW was detected on chromosome 7AS flanked by a simple sequence repeat marker of Wmc17 in Chinese wheat 262 mini-core collection by genome-wide association study. Combined with the bulked segregant RNA-sequencing (BSR-seq) analysis of an F2 genetic segregation population with extremely different TKW traits, a candidate trehalose-6-phosphate phosphatase gene located at 135.0 Mb (CS V1.0), designated as TaTPP-7A, was identified. This gene was specifically expressed in developing grains and strongly influenced grain filling and size. Overexpression (OE) of TaTPP-7A in wheat enhanced grain TKW and wheat yield greatly. Detailed analysis revealed that OE of TaTPP-7A significantly increased the expression levels of starch synthesis- and senescence-related genes involved in abscisic acid (ABA) and ethylene pathways. Moreover, most of the sucrose metabolism and starch regulation-related genes were potentially regulated by SnRK1. In addition, TaTPP-7A is a crucial domestication- and breeding-targeted gene and it feedback regulates sucrose lysis, flux, and utilization in the grain endosperm mainly through the T6P-SnRK1 pathway and sugar-ABA interaction. Thus, we confirmed the T6P signalling pathway as the central regulatory system for sucrose allocation and source-sink interactions in wheat grains and propose that the trehalose pathway components have great potential to increase yields in cereal crops.

Conservatively transmitted alleles of key agronomic genes provide insights into the genetic basis of founder parents in bread wheat (Triticum aestivum L.).

BACKGROUND: Founder parents play extremely important roles in wheat breeding. Studies into the genetic basis of founder parents and the transmission rules of favorable alleles are of great significance in improving agronomically important traits in wheat. RESULTS: Here, a total of 366 founder parents, widely grown cultivars, and derivatives of four representative founder parents were genotyped based on efficient kompetitive allele-specific PCR (KASP) markers in 87 agronomically important genes controlling yield, quality, adaptability, and stress resistance. Genetic composition analysis of founder parents and widely grown cultivars showed a consistently high frequency of favorable alleles for yield-related genes. This analysis further showed that other alleles favorable for resistance, strong gluten, dwarf size, and early heading date were also subject to selective pressure over time. By comparing the transmission of alleles from four representative founder parents to their derivatives during different breeding periods, it was found that the genetic composition of the representative founder parents was optimized as breeding progressed over time, with the number and types of favorable alleles carried gradually increasing and becoming enriched. There are still a large number of favorable alleles in wheat founder parents that have not been fully utilized in breeding selection. Eighty-seven agronomically important genes were used to construct an enrichment map that shows favorable alleles of four founder parents, providing an important theoretical foundation for future identification of candidate wheat founder parents. CONCLUSIONS: These results reveal the genetic basis of founder parents and allele transmission for 87 agronomically important genes and shed light on breeding strategies for the next generation of elite founder parents in wheat.

Survival outcome among patients with out-of-hospital cardiac arrest who received cardiopulmonary resuscitation in China: a systematic review and meta-analysis.

BACKGROUND: This study aimed to assess the survival outcomes among patients with out-of-hospital cardiac arrest (CA) who received cardiopulmonary resuscitation (CPR) in China. METHODS: Relevant studies, published between January 1, 2010 and September 5, 2022, were retrieved from databases, including EMBASE, PubMed, Cochrane Library, the China Biology Medicine disk, China National Knowledge Infrastructure, and Wanfang databases. We included clinical studies in which all patients were diagnosed with CA and underwent out-of-hospital CPR, and the outcome variables were at least one of the following: return of spontaneous circulation (ROSC), survival to admission, survival to hospital discharge, 1-month survival, achieved good neurological outcomes, and 1-year survival. Two investigators independently extracted the study data and assessed its quality using a modified Newcastle-Ottawa Scale tool. The data were pooled using random-effects models. RESULTS: Of the 3620 identified studies, 49 (63,378 patients) were included in the meta-analysis. The pooled ROSC rate was 9.0% (95% confidence interval [CI] 7.5-10.5%, I2 = 97%), the pooled survival to admission rate was 5.0% (95% CI 2.7-8.0%, I2 = 98%), and the pooled survival to discharge rate was 1.8% (95% CI 1.2-2.5%, I2 = 95%). Additionally, the ROSC rate of patients with bystander CPR was significantly higher than that of those without bystander CPR, and the pooled odds ratio (OR) was 7.92 (95% CI 4.32-14.53, I2 = 85%). The ROSC rate of participants who started CPR within 5 min was significantly higher than that of those who started CPR after 5 min, and the pooled OR was 5.92 (95% CI 1.92-18.26, I2 = 85%). The ROSC rate of participants with defibrillation was significantly higher than that of those without defibrillation, and the pooled OR was 8.52 (95% CI 3.72-19.52, I2 = 77%). CONCLUSION: The survival outcomes of out-of-hospital CPR in China are far below the world average. Therefore, the policy of providing automated external defibrillators (AEDs) in public places and strengthening CPR training for healthcare providers and public personnel should be encouraged and disseminated nationwide. Trial registration This study was registered in PROSPERO (CRD42022326165) on 29 April 2022.

Fast integration and accumulation of beneficial breeding alleles through an AB-NAMIC strategy in wheat.

Wheat (Triticum aestivum) is among the most important staple crops for safeguarding the food security of the growing world population. To bridge the gap between genebank diversity and breeding programs, we developed an advanced backcross-nested association mapping plus inter-crossed population (AB-NAMIC) by crossing three popular wheat cultivars as recurrent founders to 20 germplasm lines from a mini core collection. Selective backcrossing combined with selection against undesirable traits and extensive crossing within and between sub-populations created new opportunities to detect unknown genes and increase the frequency of beneficial alleles in the AB-NAMIC population. We performed phenotyping of 590 AB-NAMIC lines and a natural panel of 476 cultivars for six consecutive growing seasons and genotyped these 1066 lines with a 660K SNP array. Genome-wide association studies of both panels for plant development and yield traits demonstrated improved power to detect rare alleles and loci with medium genetic effects in AB-NAMIC. Notably, genome-wide association studies in AB-NAMIC detected the candidate gene TaSWEET6-7B (TraesCS7B03G1216700), which has high homology to the rice SWEET6b gene and exerts strong effects on adaptation and yield traits. The commercial release of two derived AB-NAMIC lines attests to its direct applicability in wheat improvement. Valuable information on genome-wide association study mapping, candidate genes, and their haplotypes for breeding traits are available through WheatGAB. Our research provides an excellent framework for fast-tracking exploration and accumulation of beneficial alleles stored in genebanks.

The auxin response factor TaARF15-A1 negatively regulates senescence in common wheat (Triticum aestivum L.).

Auxin plays an important role in regulating leaf senescence. Auxin response factors (ARFs) are crucial components of the auxin signaling pathway; however, their roles in leaf senescence in cereal crops are unknown. In this study, we identified TaARF15-A1 as a negative regulator of senescence in wheat (Triticum aestivum L.) by analyzing TaARF15-A1 overexpression (OE) and RNA interference lines and CRISPR/Cas9-based arf15 mutants. OE of TaARF15-A1 delayed senescence, whereas knockdown lines and knockout mutants showed accelerated leaf senescence and grain ripening. RNA-seq analysis revealed that TaARF15-A1 delays leaf senescence by negatively regulating senescence-promoting processes and positively modulating senescence-delaying genes including senescence-associated phytohormone biosynthesis and metabolism genes as well as transcription factors (TFs). We also demonstrated that TaARF15-A1 physically interacts with TaMYC2, a core jasmonic acid (JA) signaling TF that positively modulates wheat senescence. Furthermore, TaARF15-A1 suppressed the expression of TaNAM-1 (TaNAM-A1 and TaNAM-D1) via protein-protein interaction and competition with TaMYC2 for binding to its promoter to regulate senescence. Finally, we identified two haplotypes of TaARF15-A1 in global wheat collections. Association analysis revealed that TaARF15-A1-HapI has undergone strong selection during wheat breeding in China, likely owing to its earlier maturity. Thus, we identify TaARF15-A1 as a negative regulator of senescence in common wheat and present another perspective on the crosstalk between auxin and JA signaling pathways in regulating plant senescence.

A Sheathed Spike Gene, TaWUS-like Inhibits Stem Elongation in Common Wheat by Regulating Hormone Levels.

The elongation and development of wheat (Triticum aestivum L.) stem play an important role in plant architecture. The shortened stem would result in a sheathed spike and a low yield in crops. Unraveling the molecular mechanisms underlying a sheathed spike would be beneficial for plant architecture and yield improvement. We identified a novel gene, TaWUS-like (WUSCHEL-related homeobox-like), which regulated sheathed spike and plant architecture in wheat. The plant height of overexpression transgenic lines was significantly decreased and the spike was not completely elongated and enclosed in flag leaf sheaths. Moreover, the increase in tiller angle resulted in loose plant architecture and lower yield. The statistical and cytological analysis demonstrated that the length of the uppermost and secondary internode was significantly shortened, especially the uppermost internode which was only half the length of the wild-type. The size of parenchyma cells was obviously reduced and cell length on the longitudinal section was elongated insufficiently compared with wild-type. The analysis of hormone content showed that there was a lack of gibberellin A 3 (GA3) in internodes but a higher brassinosteroid (BR) content. TaWUS-like may inhibit the synthesis of GA3 and/or BR, thus affecting the function of signal transduction of these hormones, which further caused stem shortening and plant dwarfing in wheat.

Starch Metabolism in Wheat: Gene Variation and Association Analysis Reveal Additive Effects on Kernel Weight.

Kernel weight is a key determinant of yield in wheat (Triticum aestivum L.). Starch consists of amylose and amylopectin and is the major constituent of mature grain. Therefore, starch metabolism in the endosperm during grain filling can influence kernel weight. In this study, we sequenced 87 genes involved in starch metabolism from 300 wheat accessions and detected 8,141 polymorphic sites. We also characterized yield-related traits across different years in these accessions. Although the starch contents fluctuated, thousand kernel weight (TKW) showed little variation. Polymorphisms in six genes were significantly associated with TKW. These genes were located on chromosomes 2A, 2B, 4A, and 7A; none were associated with starch content or amylose content. Variations of 15 genes on chromosomes 1A and 7A formed haplotype blocks in 26 accessions. Notably, accessions with higher TKWs had more of the favorable haplotypes. We thus conclude that these haplotypes contribute additive effects to TKW.

The NAC transcription factor NAC019-A1 is a negative regulator of starch synthesis in wheat developing endosperm.

Starch is a major component of wheat (Triticum aestivum L.) endosperm and is an important part of the human diet. The functions of many starch synthesis genes have been elucidated. However, little is known about their regulatory mechanisms in wheat. Here, we identified a novel NAC transcription factor, TaNAC019-A1 (TraesCS3A02G077900), that negatively regulates starch synthesis in wheat and rice (Oryza sativa L.) endosperms. TaNAC019-A1 was highly expressed in the endosperm of developing grains and encoded a nucleus-localized transcriptional repressor. Overexpression of TaNAC019-A1 in rice and wheat led to significantly reduced starch content, kernel weight, and kernel width. The TaNAC019-A1-overexpression wheat lines had smaller A-type starch granules and fewer B-type starch granules than wild-type. Moreover, TaNAC019-A1 could directly bind to the 'ACGCAG' motif in the promoter regions of ADP-glucose pyrophosphorylase small subunit 1 (TaAGPS1-A1, TraesCS7A02G287400) and TaAGPS1-B1 (TraesCS7B02G183300) and repress their expression, thereby inhibiting starch synthesis in wheat endosperm. One haplotype of TaNAC019-B1 (TaNAC019-B1-Hap2, TraesCS3B02G092800) was positively associated with thousand-kernel weight and underwent positive selection during the Chinese wheat breeding process. Our data demonstrate that TaNAC019-A1 is a negative regulator of starch synthesis in wheat endosperm and provide novel insight into wheat yield improvement.

Development of a High-Efficient Mutation Resource with Phenotypic Variation in Hexaploid Winter Wheat and Identification of Novel Alleles in the TaAGP.L-B1 Gene.

Mutated genetic resources play an important role in gene/allele characterization. Currently, there are few hexaploid winter wheat mutated resources available. Here, we developed a hexaploid winter wheat resource by inducing mutations via EMS treatment by the single seed descent method. A broad mutation spectrum with high mutation frequency (∼19%) on phenotypic variations was identified. These mutations included spike, leaf and seed morphology, plant architecture, and heading date variations. To evaluate the efficiency of the resource for reverse genetic analysis, allelic variations in the TaAGP.L-B1 gene, encoding the AGPase large subunit, were screened by the TILLING approach. Four missense mutations were identified and one allele in line E3-1-3, resulted in an amino acid change predicated to have severe effects on gene function. The other three mutations were predicted to have no effect. Results of gene expression patterns and grain starch content demonstrated that the novel allele in E3-1-3 altered the function of TaAGP.L-B1. Our results indicated that this mutated genetic wheat resource contained broad spectrum phenotypic and genotypic variations, that may be useful for wheat improvement, gene discovery, and functional genomics.

Novel mutant alleles of the starch synthesis gene TaSSIVb-D result in the reduction of starch granule number per chloroplast in wheat.

BACKGROUND: Transient starch provides carbon and energy for plant growth, and its synthesis is regulated by the joint action of a series of enzymes. Starch synthesis IV (SSIV) is one of the important starch synthase isoforms, but its impact on wheat starch synthesis has not yet been reported due to the lack of mutant lines. RESULTS: Using the TILLING approach, we identified 54 mutations in the wheat gene TaSSIVb-D, with a mutation density of 1/165 Kb. Among these, three missense mutations and one nonsense mutation were predicted to have severe impacts on protein function. In the mutants, TaSSIVb-D was significantly down-regulated without compensatory increases in the homoeologous genes TaSSIVb-A and TaSSIVb-B. Altered expression of TaSSIVb-D affected granule number per chloroplast; compared with wild type, the number of chloroplasts containing 0-2 granules was significantly increased, while the number containing 3-4 granules was decreased. Photosynthesis was affected accordingly; the maximum quantum yield and yield of PSII were significantly reduced in the nonsense mutant at the heading stage. CONCLUSIONS: These results indicate that TaSSIVb-D plays an important role in the formation of transient starch granules in wheat, which in turn impact the efficiency of photosynthesis. The mutagenized population created in this study allows the efficient identification of novel alleles of target genes and could be used as a resource for wheat functional genomics.