Prognostic implications of systemic immune-inflammation index in myocardial infarction patients with and without diabetes: insights from the NOAFCAMI-SH registry.

BACKGROUND: It is well-known that systemic inflammation plays a crucial role in the pathogenesis and prognosis of acute myocardial infarction (AMI). The systemic immune-inflammation index (SII, platelet × neutrophil/lymphocyte ratio) is a novel index that is used for the characterization of the severity of systemic inflammation. Recent studies have identified the high SII level as an independent predictor of poor outcomes in patients with AMI. We aimed to investigate the prognostic implications of SII in AMI patients with and without diabetes mellitus (DM). METHODS: We included 2111 patients with AMI from February 2014 to March 2018. Multivariable Cox regression analyses were performed to estimate the hazard ratios (HRs) and 95% confidence intervals (CIs) of all-cause death and cardiovascular (CV) death. Multiple imputation was used for missing covariates. RESULTS: Of 2111 patients (mean age: 65.2 ± 12.2 years, 77.5% were males) analyzed, 789 (37.4%) had DM. Generalized additive model analyses showed that as the SII increased, the C-reactive protein and peak TnT elevated while the LVEF declined, and these associations were similar in patients with and without DM. During a median of 2.5 years of follow-up, 210 all-cause deaths and 154 CV deaths occurred. When treating the SII as a continuous variable, a higher log-transformed SII was significantly associated with increased all-cause mortality (HR: 1.57, 95%CI: 1.02-2.43) and CV mortality (HR: 1.85, 95%CI 1.12-3.05), and such an association was also significant in the diabetics (HRs and 95%CIs for all-cause death and CV death were 2.90 [1.40-6.01] and 3.28 [1.43-7.57], respectively) while not significant in the nondiabetics (Pinteraction for all-cause death and CV death were 0.019 and 0.049, respectively). Additionally, compared to patients with the lowest tertiles of SII, those with the highest tertiles of SII possessed significantly higher all-cause mortality (HR: 1.82, 95%CI 1.19-2.79) and CV mortality (HR: 1.82, 95%CI 1.19-2.79) after multivariable adjustment, and this relationship remained pronounced in the diabetics (HRs and 95%CIs for all-cause death and CV death were 2.00 [1.13-3.55] and 2.09 [1.10-3.98], respectively) but was not observed in the nondiabetics (HRs and 95%CIs for all-cause death and CV death were 1.21 [0.75-1.97] and 1.60 [0.89-2.90], respectively). Our restricted cubic splines analyses indicated a pronounced linear association between SII and mortality only in diabetics. CONCLUSIONS: In AMI patients with DM, high SII is an independent predictor of poor survival and may be helpful for patient's risk stratification.

Association of stress hyperglycemia ratio with in-hospital new-onset atrial fibrillation and long-term outcomes in patients with acute myocardial infarction.

AIMS: To investigate the predictive value and prognostic impact of stress hyperglycemia ratio (SHR) for new-onset atrial fibrillation (NOAF) complicating acute myocardial infarction (AMI). MATERIALS AND METHODS: This retrospective study included 2145 AMI patients without AF history between February 2014 and March 2018. SHR was calculated using fasting blood glucose (mmol/L)/[1.59*HbA1c (%)-2.59]. The association between SHR and post-MI NOAF was assessed with multivariable logistic regression analyses. The primary outcome was a composite of cardiac death, heart failure hospitalisation, recurrent MI, and ischaemic stroke (MACE). Cox regression-adjusted hazard ratios with 95% confidence intervals (CI) were estimated for MACE. RESULTS: A total of 245 (11.4%) patients developed NOAF. In the multivariable logistic regression analyses, SHR (each 10% increase) was significantly associated with increased risks of NOAF in the whole population (OR: 1.05, 95% CI: 1.01-1.10), particularly in non-diabetic individuals (OR:1.08, 95% CI: 1.01-1.17). During a median follow-up of 2.7 years, 370 (18.5%) MACEs were recorded. The optimal cut-off value of SHR for MACE prediction was 1.119. Patients with both high SHR (≥1.119) and NOAF possessed the highest risk of MACE compared to those with neither high SHR nor NOAF after multivariable adjustment (HR: 2.18, 95% CI: 1.39-3.42), especially for diabetics (HR: 2.63, 95% CI: 1.41-4.91). Similar findings were observed using competing-risk models. CONCLUSIONS: SHR is an independent predictor of post-MI NOAF in non-diabetic individuals. Diabetic patients with both high SHR and NOAF had the highest risk of MACE, suggesting that therapies targeting SHR may be considered in these patients. TRIAL REGISTRATION: ClinicalTrials.gov, NCT03533543.

Endophytes Alleviate Drought-Derived Oxidative Damage in Achnatherum inebrians Plants Through Increasing Antioxidants and Regulating Host Stress Responses.

Endophytes generally increase antioxidant contents of plants subjected to environmental stresses. However, the mechanisms by which endophytes alter the accumulation of antioxidants in plant tissues are not entirely clear. We hypothesized that, in stress situations, endophytes would simultaneously reduce oxidative damage and increase antioxidant contents of plants and that the accumulation of antioxidants would be a consequence of the endophyte ability to regulate the expression of plant antioxidant genes. We investigated the effects of the fungal endophyte Epichloë gansuensis (C.J. Li & Nan) on oxidative damage, antioxidant contents, and expression of representative genes associated with antioxidant pathways in Achnatherum inebrians (Hance) Keng plants subjected to low (15%) and high (60%) soil moisture conditions. Gene expression levels were measured using RNA-seq. As expected, the endophyte reduced the oxidative damage by 17.55% and increased the antioxidant contents by 53.14% (on average) in plants subjected to low soil moisture. In line with the accumulation of antioxidants in plant tissues, the endophyte increased the expression of most plant genes associated with the biosynthesis of antioxidants (e.g., MIOX, crtB, gpx) while it reduced the expression of plant genes related to the metabolization of antioxidants (e.g., GST, PRODH, ALDH). Our findings suggest that endophyte ability of increasing antioxidant contents in plants may reduce the oxidative damage caused by stresses and that the fungal regulation of plant antioxidants would partly explain the accumulation of these compounds in plant tissues.

Prognostic impact of stress hyperglycemia ratio in acute myocardial infarction patients with and without diabetes mellitus.

BACKGROUND AND AIMS: Stress hyperglycemia ratio (SHR) is associated with increased in-hospital morbidity and mortality in patients with acute myocardial infarction (AMI). We aimed to investigate the impact of stress "hyperglycemia" on long-term mortality after AMI in patients with and without diabetes mellitus (DM). METHODS AND RESULTS: We included 2089 patients with AMI between February 2014 and March 2018. SHR was measured with the fasting glucose divided by the estimated average glucose derived from glycosylated hemoglobin (HbA1c). The primary endpoint was all-cause death. Of 2 089 patients (mean age: 65.7 ± 12.4, 76.7% were men) analyzed, 796 (38.1%) had DM. Over a median follow-up of 2.7 years, 141 (6.7%) and 150 (7.2%) all-cause deaths occurred in the diabetic and nondiabetic cohorts, respectively. Compared with participants with low SHR (<1.24 in DM; <1.14 in non-DM), the hazard ratios and 95% confidence intervals for those with high SHR (≥1.24 in DM; ≥1.14 in non-DM) for all-cause mortality were 2.23 (1.54-3.23) and 1.79 (1.15-2.78); for cardiovascular mortality were 2.42 (1.63-3.59) and 2.10 (1.32-3.35) in DM and non-DM subjects, respectively. The mortality prediction was improved in the diabetic individuals with the incorporation of SHR into the Global Registry of Acute Coronary Events (GRACE) score, showing an increase in a continuous net reclassification index of 0.184 (95%CI: 0.003-0.365) and an absolute integrated discrimination improvement of 0.014 (95%CI: 0.002-0.025). CONCLUSION: The improvement in the prediction of long-term mortality beyond the GRACE score indicates the potential of SHR as a biomarker for post-MI risk stratification among patients with DM. REGISTRATION NUMBER FOR CLINICAL TRIALS: NCT03533543.

ZPI prevents ox-LDL-mediated endothelial injury leading to inhibition of EndMT, inflammation, apoptosis, and oxidative stress through activating Pi3k/Akt signal pathway.

Oxidized low-density lipoprotein (ox-LDL)-mediated endothelial dysfunction exerts an essential role in the development of atherosclerosis. Protein Z-dependent protease inhibitor (ZPI), a member of the serine protease inhibitor superfamily, could inhibit the function of activated coagulation factor X (FXa) via interaction with protein Z (PZ). Studies have pointed out that ZPI was statistically related to atherosclerotic diseases, which may have a robust cardiovascular protective effect. However, the underlying mechanism of ZPI on ox-LDL-mediated endothelial injury requires further elucidation. Human umbilical vein endothelial cells (HUVECs) were treated with ox-LDL (100 µg/ml) and ZPI (10 µg/ml). Cell viability was measured by the Cell Counting Kit-8 (CCK-8) assay. Cell apoptosis, oxidative stress, and endothelial-to-mesenchymal transition (EndMT) were analyzed by immunofluorescence (IF). Cell migration was measured using a wound-healing assay. Quantitative real-time polymerase chain reaction and western blot analysis were performed to determine messenger RNA and protein expression. Ox-LDL (100 µg/ml, 48 h) significantly reduced cell viability and migration, increased EndMT, inflammation, apoptosis, and oxidative stress. The related protein expression of phosphatidylinositol 3 kinase/protein kinase B (Pi3k/Akt) signal pathway in HUVECs was also simultaneously decreased. We also discovered that ZPI treatment could prevent ox-LDL-mediated endothelial injury through the improvement of cell viability and alleviation of apoptosis, oxidative stress, EndMT, and inflammation. Thus, the protective effect of ZPI on HUVECs may be mediated by activation of the Pi3k/Akt signal pathway. ZPI may exert an important protective role in HUVECs dysfunction triggered by ox-LDL via activation of the Pi3k/Akt signal pathway. Therefore, ZPI may possess potential therapeutic effects on atherosclerotic endothelial injury-related diseases.

An epigenome-wide DNA methylation study of workers with an occupational exposure to lead.

Using the Illumina Infinium Methylation EPIC BeadChip (850 K), we report genome-wide differences in DNA methylation between occupational workers with high blood Pb levels (BLL) and low BLL. We observed 356 significant CpG sites. In particular, GSTM1 methylation was negatively associated with high BLL. Gene ontology and KEGG pathway enrichment analysis were performed to determine the complex biological systems of Pb exposure. Enriched gene sets were involved in the oxidation-reduction process, glutathione derivative biosynthetic process and nervous system development. To our knowledge, this is the first study to employ an 850 K array to examine whether workers with occupational exposure to high levels of Pb can have an epigenetic effect on the DNA methylation pattern.

A New Self-Powered Sensor Using the Radial Field Piezoelectric Diaphragm in d33 Mode for Detecting Underwater Disturbances.

This paper presents a new sensor based on a radial field bulk piezoelectric diaphragm to provide energy-efficient and high-performance situational sensing for autonomous underwater vehicles (AUVs). This sensor is self-powered, does not need an external power supply, and works efficiently in d33 mode by using inter-circulating electrodes to release the radial in-plane poling. Finite element analysis was conducted to estimate the sensor behavior. Sensor prototypes were fabricated by microfabrication technology. The dynamic behaviors of the piezoelectric diaphragm were examined by the impedance spectrum. By imitating the underwater disturbance and generating the oscillatory flow velocities with a vibrating sphere, the performance of the sensor in detecting the oscillatory flow was tested. Experimental results show that the sensitivity of the sensor is up to 1.16 mV/(mm/s), and the detectable oscillatory flow velocity is as low as 4 mm/s. Further, this sensor can work well under a disturbance with low frequency. The present work provides a good application prospect for the underwater sensing of AUVs.

Role of Epichloë Endophytes in Defense Responses of Cool-Season Grasses to Pathogens: A Review.

Various cool-season grasses are infected by Epichloë endophyte, and this symbiotic relationship is always of benefit to the host grass due to an increased resistance to abiotic and biotic stresses. Fungal diseases adversely affect the yield, quality, and economic benefits of rangelands, which affects the production of animal husbandry. Therefore, it is imperative to breed resistant cultivars and to better understand the role of fungal endophytes in order to protect grasses against pathogens. The present review introduces research regarding how these endophytes affect the growth of pathogens in vitro and how they change the resistance of host plants to plant diseases. From the perspective of physical defense, changes in physiological indexes, and secretion of chemical compounds, we summarize the potential mechanisms by which endophytes are able to enhance the disease resistance of a host grass. Through these, we aim to establish a solid theoretical foundation for plant disease control and disease resistance breeding by application of fungal endophytes. A broader understanding of fungal endophyte effects on hosts could create a new opportunity for managing or introducing fungal symbioses in both agronomic or non-agronomic ecosystems.

Rutin alleviates Pb-induced oxidative stress, inflammation and cell death via activating Nrf2/ARE system in SH-SY5Y cells.

Lead (Pb) is harmful to almost all organs, particularly the developmental neural system, and previous studies revealed oxidative stress played an important role in Pb neurotoxicity. Rutin, a type of flavonoid glycoside found in various plants and fruits, is widely used as a dietary supplement due to its antioxidant and anti-inflammatory properties, but whether rutin could protect against Pb neurotoxicity is unclear. In this study, we found rutin treatment significantly alleviated Pb-induced cell death, oxidative stress, and inflammation, resulting in cell survival. Moreover, rutin treatment promoted nuclear factor erythroid 2-related factor 2 (Nrf2) translocation from cytoplasm to nucleus and subsequently activated antioxidant and detoxifying enzymes expression including HO-1. Knocking down Nrf2 by siRNA transfection abolished this protection of rutin against Pb. Overall, rutin could alleviate Pb-induced oxidative stress, inflammation, and cell death by activating the Nrf2/antioxidant response elements (ARE) system.

Prognostic impact of new-onset atrial fibrillation in myocardial infarction with and without improved ejection fraction.

AIMS: Improvement in left ventricular ejection fraction (impEF) often presents in contemporary acute myocardial infarction (AMI) patients. New-onset atrial fibrillation (NOAF) during AMI is an important predictor of subsequential heart failure (HF), while its impact on the trajectory of post-MI left ventricular ejection fraction (LVEF) and prognostic implication in patients with and without impEF remains undetermined. We aimed to investigate the prognostic impacts of NOAF in AMI patients with and without impEF. METHODS AND RESULTS: Consecutive AMI patients without a prior history of AF between February 2014 and March 2018 with baseline LVEF ≤ 40% and had ≥1 LVEF measurement after baseline were included. ImpEF was defined as a baseline LVEF ≤ 40% and a re-evaluation showed both LVEF > 40% and an absolute increase of LVEF ≥ 10%. Persistently reduced EF (prEF) was defined as the second measurement of LVEF either ≤40% or an absolute increase of LVEF < 10%. The primary endpoint was a major adverse cardiac event (MACE) that was composed of cardiovascular death and HF hospitalization. Cox regression analysis and competing risk analysis were performed to assess the association of post-MI NOAF with MACE. Among 293 patients (mean age: 66.6 ± 11.3 years, 79.2% of males), 145 (49.5%) had impEF and 67 (22.9%) developed NOAF. Higher heart rate (odds ratio [OR]: 0.84, 95% confidence interval [CI]: 0.73-0.97; P = 0.015), prior MI (OR: 0.25, 95% CI: 0.09-0.69; P = 0.008), and STEMI (OR: 0.40, 95% CI: 0.21-0.77; P = 0.006) were independent predictors of post-MI impEF. Within up to 5 years of follow-up, there were 22 (15.2%) and 53 (35.8%) MACE in patients with impEF and prEF, respectively. NOAF was an independent predictor of MACE in patients with impEF (hazard ratio [HR]: 7.34, 95% CI: 2.49-21.59; P < 0.001) but not in those with prEF (HR: 0.78, 95% CI: 0.39-1.55; P = 0.483) after multivariable adjustment. Similar results were obtained when accounting for the competing risk of all-cause death (subdistribution HR and 95% CIs in impEF and prEF were 6.47 [2.32-18.09] and 0.79 [0.39-1.61], respectively). CONCLUSIONS: The NOAF was associated with an increased risk of cardiovascular outcomes in AMI patients with impEF.

A Novel Bird-Shape Broadband Piezoelectric Energy Harvester for Low Frequency Vibrations.

This work presents a novel bird-shaped broadband piezoelectric energy harvester based on a two-DOF crossed beam for low-frequency environmental vibrations. The harvester features a cantilever mounted on a double-hinged beam, whose rotating motions effectively diminish its natural frequencies. Numerical simulation based on the finite element method is conducted to analyze the modal shapes and the harmonic response of the proposed harvester. Prototypes are fabricated and experiments are carried out by a testing system, whose results indicate a good agreement with the simulation. The multi-frequency energy harvesting is achieved at the first-, second-, and fifth-order resonances. In particular, the proposed harvester demonstrates the remarkable output characteristics of 9.53 mW and 1.83 mW at frequencies as low as 19.23 HZ and 45.38 Hz, which are superior to the majority of existing energy harvesters. Besides, the influences of key parameters on the harvesting performance are experimentally investigated to optimize the environmental adaptability of the harvester. This work provides a new perspective for efficiently harvesting the low-frequency vibration energy, which can be utilized for supplying power to electronic devices.

Prognostic implications of the 4S-AF scheme to characterize new-onset atrial fibrillation after myocardial infarction.

AIMS: The 4S-AF scheme (Stroke risk [St], Symptom severity [Sy], Severity of atrial fibrillation burden [Sb], Substrate [Su]) is a novel approach for the holistic characterization of AF. We aimed to investigate the prognostic implications of the 4S-AF scheme score in acute myocardial infarction (AMI) patients with new-onset atrial fibrillation (NOAF). METHODS: We included 262 patients with post-MI NOAF who had complete data for the 4S-AF scheme evaluation between February 2014 and March 2018. The 4S-AF scheme score was calculated as a sum of each domain with a maximum of 9. The primary outcome was all-cause death. RESULTS: Of 262 patients (66.0% males, mean age 74.5 ± 10.4 years) were analyzed. The mean 4S-AF scheme score was 5.0 ± 1.6. There were 62 (27.3%) all-cause deaths within a median follow-up of 2.6 years. According to multivariable Cox regression models, each 1-point increase in the 4S-AF scheme score was significantly associated with 39% increased all-cause mortality (HR: 1.39, 95% CI: 1.16-1.67, P<0.001), which was mainly driven by the Sb (HR: 1.43, 95%CI: 1.05-1.95, P = 0.025) and Su (HR: 1.53, 95%CI: 1.17-2.02, P = 0.002) domains. Adding the 4S-AF scheme score on top of the Global Registry of Acute Coronary Events score could significantly improve its discriminative capability (C-index from 0.713 to 0.761, P = 0.039) and reclassification performance (continuous net reclassification improvement: 41.0% [95%CI: 12.5-69.6]; integrated discrimination improvement: 5.1% [95%CI: 2.2-8.1]) for all-cause mortality. CONCLUSIONS: Characterization of NOAF using the 4S-AF scheme aids in the risk stratification of AMI patients with NOAF.

TRIM21 deficiency protects against atrial inflammation and remodeling post myocardial infarction by attenuating oxidative stress.

Atrial remodeling is a major contributor to the onset of atrial fibrillation (AF) after myocardial infarction (MI). Tripartite motif-containing protein 21 (TRIM21), an E3 ubiquitin protein ligase, is associated with pathological cardiac remodeling and dysfunction. However, the role of TRIM21 in postmyocardial infarction atrial remodeling and subsequent AF remains unclear. This study investigated the role of TRIM21 in post myocardial infarction atrial remodeling using TRIM21 knockout mice and explored the underlying mechanisms by overexpressing TRIM21 in HL-1 atrial myocytes using a lentiviral vector. The expression of TRIM21 in the left atrium of the mouse MI model was significantly elevated. TRIM21 deficiency alleviated MI-induced atrial oxidative damage, Cx43 downregulation, atrial fibrosis and enlargement, and abnormalities in electrocardiogram parameters (prolongation of the P-wave and PR interval). TRIM21 overexpression in atrial myocyte HL-1 cells further enhanced oxidative damage and Cx43 downregulation, whereas these effects were reversed by the reactive oxygen species scavenger N-acetylcysteine. The findings suggest that TRIM21 likely induces Nox2 expression mechanistically by activating the NF-κB pathway, which in turn leads to myocardial oxidative damage, inflammation, and atrial remodeling.

Effect of Epichloë gansuensis Endophyte on Seed-Borne Microbes and Seed Metabolites in Achnatherum inebrians.

The seed-borne microbiota and seed metabolites of the grass Achnatherum inebrians, either host to Epichloë gansuensis (endophyte infected [EI]) or endophyte free (EF), were investigated. This study determined the microbial communities both within the seed (endophytic) and on the seed surface (epiphytic) and of the protective glumes by using Illumina sequencing technology. Epichloë gansuensis decreased the richness of the seed-borne microbiota except for the epiphytic fungi of glumes and also decreased the diversity of seed-borne microbiota. In addition, metabolites of seeds and glumes were detected using liquid chromatography-mass spectrometry (LC-MS). Unlike with the seeds of EF plants, the presence of E. gansuensis resulted in significant changes in the content of 108 seed and 31 glume metabolites. A total of 319 significant correlations occurred between seed-borne microbiota and seed metabolites; these correlations comprised 163 (147 bacterial and 16 fungal) positive correlations and 156 (136 bacterial and 20 fungal) negative correlations. Meanwhile, there were 42 significant correlations between glume microbiota and metabolites; these correlations comprised 28 positive (10 bacterial and 18 fungal) and 14 negative (9 bacterial and 5 fungal) correlations. The presence of E. gansuensis endophyte altered the communities and diversities of seed-borne microbes and altered the composition and content of seed metabolites, and there were many close and complex relationships between microbes and metabolites. IMPORTANCE The present study was to investigate seed-borne microbiota and seed metabolites in Achnatherum inebrians using high-throughput sequencing and LC-MS technology. Epichloë gansuensis decreased the richness of the seed-borne microbiota except for the epiphytic fungi of glumes and also decreased the diversity of seed-borne microbiota. Compared with endophyte-free plants, the content of 108 seed and 31 glume metabolites of endophyte-infected plants was significantly changed. There were 319 significant correlations between seed-borne microbiota and seed metabolites and 42 significant correlations between glume microbiota and metabolites.

Vertically Transmitted Epichloë Systemic Endophyte Enhances Drought Tolerance of Achnatherum inebrians Host Plants through Promoting Photosynthesis and Biomass Accumulation.

Achnatherum inebrians (drunken horse grass, DHG) plants, a dominant grass species in the arid and semi-arid regions of northwest China, symbiotic with an Epichloë fungal endophyte, is well adapted to drought. However, little is known about how the presence of the foliar Epichloë endophyte enhances the tolerance of DHG to drought at the molecular level. This study explored the positive effects of the presence of the Epichloë endophyte on plant growth, biomass, and photosynthetic efficiency and processes of DHG under non-drought and two drought (moderate and severe) treatments, using RNA sequencing to compare transcriptomes. The transcriptome results showed that 32 selected unigenes involved in the photosynthesis processes within Epichloë symbiotic plants were differently expressed (DEGs) versus non-symbiotic plants. The majority of these selected DEGs were upregulated in Epichloë symbiotic plants versus non-symbiotic plants, such as upregulated unigenes (c51525.graph_c1, c47798.graph_c0 & c64087.graph_c0) under drought conditions. In line with the transcriptomes data, the presence of the Epichloë endophyte promoted the photosynthetic rate and biomass accumulation of DHG plants, and the relationship between the photosynthetic rate and biomass is linear and significant. The presence of the endophyte only increased the biomass per tiller of DHG plants under drought. This study provides further insights into the molecular mechanisms that underlie the enhanced plant growth and drought tolerance of Epichloë-symbiotic DHG plants.

Cuticular Wax Modification by Epichloë Endophyte in Achnatherum inebrians under Different Soil Moisture Availability.

The cuticular wax serves as the outermost hydrophobic barrier of plants against nonstomatal water loss and various environmental stresses. An objective of this study was to investigate the contribution of the mutualistic fungal endophyte Epichloë gansuensis to leaf cuticular wax of Achnatherum inebrians under different soil moisture availability. Through a pot experiment and gas chromatography-mass spectrometry (GC-MS) analysis, our results indicated that the hydrocarbons were the dominant components of leaf cuticular wax, and the proportion of alcohols, aldehydes, amines, and ethers varied with the presence or absence of E. gansuensis and different soil moisture availability. Amines and ethers are unique in endophyte-free (EF) A. inebrians plants and endophyte-infected (EI) A. inebrians plants, respectively. By transcriptome analysis, we found a total of 13 differentially expressed genes (DEGs) related to cuticular biosynthesis, including FabG, desB, SSI2, fadD, BiP, KCS, KAR, FAR, and ABCB1. A model is proposed which provides insights for understanding cuticular wax biosynthesis in the association of A. inebrians plants with E. gansuensis. These results may help guide the functional analyses of candidate genes important for improving the protective layer of cuticular wax of endophyte-symbiotic plants.

The effect of Epichloë endophyte on phyllosphere microbes and leaf metabolites in Achnatherum inebrians.

Upon exposure to the prevailing environment, leaves become increasingly colonized by fungi and bacteria located on the surface (epiphytic) or within (endophytic) the leaves. Many cool season grasses, including Achnatherum inebrians, host a seed-borne, intercellular, mutualistic Epichloë fungal endophyte, the growth of which is synchronized with the host grass. A study utilizing illumina sequencing was used to examine the epiphytic and endophytic microbial communities in Epichloë endophyte-infected and endophyte-free A. inebrians plants growing under hot dry field conditions. The presence of Epichloë endophyte increased the Shannon and decreased Simpson diversity of bacterial and fungal communities. Sphingomonas and Hymenobacter bacteria and Filobasidium and Mycosphaerella fungi were growing largely epiphytically, whereas Methylobacterium, Escherichia-Shigella, and the fungus Blumeria were mostly found within leaves with the location of colonization influenced by the Epichloë endophyte. In addition, leaf metabolites in Epichloë-infected and Epichloë-free leaves were examined using LC/MS. Epichloë was significantly correlated with 132 metabolites.

Transcriptomic Analyses Reveals Molecular Regulation of Photosynthesis by Epichloë endophyte in Achnatherum inebrians under Blumeria graminis Infection.

Photosynthesis is essential for the growth of all green plants, and the presence of an Epichloë endophyte enhances the photosynthesis of Achnatherum inebrians (drunken horse grass, DHG), including when it is under attack by fungal pathogens. However, few studies have examined the mechanism of the increased photosynthetic activity at the molecular level of A. inebrians when it is under pathogen stress. The present study investigated the effects of the presence of the Epichloë endophyte on the net photosynthetic rate, intercellular CO2 concentration, stomatal conductance, and transpiration rate of DHG plants under a Blumeria graminis infection condition, and we compared the transcriptomes using RNA sequencing. The results showed that the photosynthetic rate of Epichloë endophyte-infected (E+) plants was higher under the B. graminis infection condition, and also without this pathogen, when it was compared with Epichloë endophyte-free (E-) plants. The E+ plants uninfected with B. graminis had 15 up-regulated unigenes that are involved in photosynthesis which were compared to the E- plants that were uninfected with this pathogen. This suggests that the presence of an Epichloë endophyte up-regulates the genes that are involved in the process of photosynthesis.

Abscisic Acid May Play a Critical Role in the Moderating Effect of Epichloë Endophyte on Achnatherum inebrians under Drought Stress.

Water scarcity is a major constraint that adversely affects plant development and growth. Abscisic acid (ABA) is a plant stress hormone that is rapidly synthesized and can induce stomatal closure to conserve water, thereby alleviating the drought stress of plants. The Epichloë endophyte enhances the drought tolerance of Achnatherum inebrians (drunken horse grass, DHG). To better understand how the Epichloë endophyte enhances drought tolerance, DHG plants without (EF) and with (EI), an Epichloë endophyte, were grown under 20% and 60% soil water conditions (SWC), and the leaves of the three treatments of EF and EI plants were sprayed with ABA solution (1 mg/L); fluridone (FLU), the ABA biosynthesis inhibitor solution (1 mg/L); and distilled water, respectively. Four-weeks later, the results indicated that the exogenous ABA application promoted plant growth, stomatal conductance, and photosynthetic rate, while the opposite effect occurred with plants sprayed with FLU. The differences between EI and EF plants in tiller number, height, chlorophyll content, stomata conductance, and photosynthetic rate were highest when sprayed with ABA. Thus, it is concluded that ABA might be involved in the moderating effect of Epichloë endophytes on DHG plants exposed to drought by maintaining growth and improving photosynthetic efficiency.

TRIM21 aggravates cardiac injury after myocardial infarction by promoting M1 macrophage polarization.

Macrophage polarization followed by myocardial infarction (MI) is essential for wound healing. Tripartite motif-containing protein 21 (TRIM21), a member of E3 ubiquitin ligases, is emerging as a mediator in cardiac injury and heart failure. However, its function in modulating post-MI macrophage polarization remains elusive. Here, we detected that the levels of TRIM21 significantly increased in macrophages of wild-type (WT) mice after MI. In contrast, MI was ameliorated in TRIM21 knockout (TRIM21-/-) mice with improved cardiac remodeling, characterized by a marked decrease in mortality, decreased infarct size, and improved cardiac function compared with WT-MI mice. Notably, TRIM21 deficiency impeded the post-MI apoptosis and DNA damage in the hearts of mice. Consistently, the accumulation of M1 phenotype macrophages in the infarcted tissues was significantly reduced with TRIM21 deletion. Mechanistically, the deletion of TRIM21 orchestrated the process of M1 macrophage polarization at least partly via a PI3K/Akt signaling pathway. Overall, we identify TRIM21 drives the inflammatory response and cardiac remodeling by stimulating M1 macrophage polarization through a PI3K/Akt signaling pathway post-MI.