Identification of Zinc Efficiency-Associated Loci (ZEALs) and Candidate Genes for Zn Deficiency Tolerance of Two Recombination Inbred Line Populations in Maize.

Zinc (Zn) deficiency is one of the most common micronutrient disorders in cereal plants, greatly impairing crop productivity and nutritional quality. Identifying the genes associated with Zn deficiency tolerance is the basis for understanding the genetic mechanism conferring tolerance. In this study, the K22×BY815 and DAN340×K22 recombination inbred line (RIL) populations, which were derived from Zn-inefficient and Zn-efficient inbred lines, were utilized to detect the quantitative trait loci (QTLs) associated with Zn deficiency tolerance and to further identify candidate genes within these loci. The BLUP (Best Linear Unbiased Prediction) values under Zn-deficient condition (-Zn) and the ratios of the BLUP values under Zn deficient condition to the BLUP values under Zn-sufficient condition (-Zn/CK) were used to perform linkage mapping. In QTL analysis, 21 QTLs and 33 QTLs controlling the Zn score, plant height, shoot and root dry weight, and root-to-shoot ratio were detected in the K22×BY815 population and the DAN340×K22 population, explaining 5.5-16.6% and 4.2-23.3% of phenotypic variation, respectively. In addition, seventeen candidate genes associated with the mechanisms underlying Zn deficiency tolerance were identified in QTL colocalizations or the single loci, including the genes involved in the uptake, transport, and redistribution of Zn (ZmIRT1, ZmHMAs, ZmNRAMP6, ZmVIT, ZmNAS3, ZmDMAS1, ZmTOM3), and the genes participating in the auxin and ethylene signal pathways (ZmAFBs, ZmIAA17, ZmETR, ZmEIN2, ZmEIN3, ZmCTR3, ZmEBF1). Our findings will broaden the understanding of the genetic structure of the tolerance to Zn deficiency in maize.

Decreased tryptophan hydroxylase 2 mRNA and protein expression, decreased brain serotonin concentrations, and anxiety-like behavioral changes in a rat model of simulated transport stress.

Transport stress causes not only physiological changes but also behavioral responses, including anxiety-like and depression-like behaviors in animals. The serotonergic system in the brain plays a pivotal role in processing anxiety. This study aimed to explore changes in concentrations of 5-hydroxytryptamine (serotonin), and the expression changes of tryptophan hydroxylase 2 (TPH2) mRNA and protein associated with anxiety-related behavioral responses under transport stress. A model of simulated transport stress was established in 40 adult male Sprague-Dawley rats, including a control group (n = 20) and a transport stress (TS) group (n = 20). The results showed that the rats in the TS group exhibited an increased feeding latency in the novelty-suppressed feeding test and a reduced frequency and dwelling time in the central area in the open-field test (OFT). Two hours following the final behavioral test, blood samples were collected. Creatine kinase (CK) activities and glucose and corticosterone concentrations in serum were significantly higher in the rats in the TS group than in the control group. Transport stress also significantly reduced the concentrations of 5-hydroxytryptamine in the hippocampus, striatum, and raphe nuclei and also reduced the expression levels of mRNA and protein for TPH2 in the raphe nuclei. Notably, the number of Fos-immunoreactive neurons was higher in the dorsal raphe nucleus under transport stress, whereas the number of 5-hydroxytryptamine-positive neurons was significantly lower. These findings are consistent with the hypothesis that the 5-hydroxytryptamine transmitter in the hippocampus, striatum, and raphe nuclei is involved in processing anxiety-related behavioral responses under transport stress. Lay summary Physiological and psychological stress responses were induced in a rat model of simulated transport stress. We examined whether serotonin in the brain may be involved in mediating behavioral responses following exposure to transport stress. Tissue concentrations of serotonin in rat brain regions, including the hippocampus, striatum, and raphe nuclei, were reduced following exposure to transport stress. Expression of tryptophan hydroxylase 2 mRNA and protein, which catalyses serotonin synthesis, as well as numbers of serotonin-immunoreactive neurons, were decreased in the brainstem raphe nuclei.

Royal Jelly Ameliorates Behavioral Deficits, Cholinergic System Deficiency, and Autonomic Nervous Dysfunction in Ovariectomized Cholesterol-Fed Rabbits.

Estrogen deficiency after menopause is associated with autonomic nervous changes, leading to memory impairment and increased susceptibility to Alzheimer's disease (AD). Royal jelly (RJ) from honeybees (Apis mellifera) has estrogenic activity. Here, we investigated whether RJ can improve behavior, cholinergic and autonomic nervous function in ovariectomized (OVX) cholesterol-fed rabbits. OVX rabbits on high-cholesterol diet were administered with RJ for 12 weeks. The results showed that RJ could significantly improve the behavioral deficits of OVX cholesterol-fed rabbits and image structure of the brain. RJ reduced body weight, blood lipid, as well as the levels of amyloid-beta (Aß), acetylcholinesterase (AchE), and malonaldehyde (MDA) in the brain. Moreover, RJ also increased the activities of choline acetyltransferase (ChAT) and superoxide dismutase (SOD) in the brain, and enhanced heart rate variability (HRV) and Baroreflex sensitivity (BRS) in OVX cholesterol-fed rabbits. Furthermore, RJ was also shown to reduce the content of Evans blue and the expression levels of Aß, beta-site APP cleaving enzyme 1(BACE1), and receptor for advanced glycation end products (RAGE), and increase the expression level of LDL(low density lipoprotein) receptor-related protein 1 (LRP-1) in the brain. Our findings suggested that RJ has beneficial effects in neurological disorders of postmenopausal women, which were associated with reducing cholesterol and Aß deposition, enhancing the estrogen levels and the activities of cholinergic and antioxidant systems, and ameliorating the blood⁻brain barrier (BBB) permeability and restoring autonomic nervous system.

ß-arrestin-2 is involved in irisin induced glucose metabolism in type 2 diabetes via p38 MAPK signaling.

Type 2 diabetes mellitus (T2DM) is a common metabolic disease worldwide. It has been reported that irisin play regulatory role in glucose metabolism in T2DM. However, the underlying mechanism involved in that is not completely known. Herein, we determined the novel role of ß-arrestin-2 in irisin-induced glucose utilization in diabetes. Effects of irisin and ß-arrestin-2 on glucose utilization were investigated in a rat model of diabetes and in diabetic C2C12 cells in vitro. Results showed that irisin had positive role in glucose metabolism via regulating glucose tolerance as well as uptake in cardiac and skeletal muscle tissues, as evidenced by IPGTT, 2-deoxyglucose uptake and plasma membrane GLUT-4 assay. ß-arrestin-2 also improved glucose utilization in diabetes by increasing the glucose uptake and insulin sensitivity, as shown in mice overexpressing ß-arrestin-2. In diabetic C2C12 myocytes, irisin-induced GLUT4 and glucose uptake were restrained by ß-arrestin-2 inhibition, but was enhanced by ß-arrestin-2 overexpression. Additionally, irisin and ß-arrestin-2 increased the activation of p38 MAPK in diabetic C2C12 cells, and the repression of p38 MAPK activation decreased the glucose uptake and plasma membrane GLUT-4 was enhanced by irisin and ß-arrestin-2 overexpression in diabetic C2C12 cells. In conclusion, we demonstrated that ß-arrestin-2 has a crucial role in irisin induced glucose metabolism in T2DM by regulating the p38 MAPK signaling. This might present a novel therapeutic target of treatment for human diabetes.

Correction to: Alzheimer-like brain metabolic and structural features in cholesterol-fed rabbit detected by magnetic resonance imaging.

Unfortunately, after publication of this article [1], it was noticed that the order of correspondence addresses was reversed. Maosheng Xu should be listed before Minli Chen. The correct order of correspondence can be seen in this correction article.

Alzheimer-like brain metabolic and structural features in cholesterol-fed rabbit detected by magnetic resonance imaging.

BACKGROUND: Hypercholesterolemia is known to increase the risk of AD in later life, the purpose of this study is to illustrate brain metabolic and structural changes in a cholesterol-fed rabbit model of Alzheimer's Disease (AD) by using clinical 3 T Magnetic Resonance Imaging (MRI). METHODS: The Institutional Animal Care and Use Committee of Zhejiang Chinese Medical University approved the study. Totally 16 Japanese White Rabbits (JWR) were randomly divided into 2 groups including normal control group fed with routine diet (group NC) and high cholesterol diet group (group CD) fed a 2% cholesterol diet with 0.24 ppm copper in the drinking water for 12 weeks. Magnetic resonance spectroscopy (MRS) and structural image of rabbit brain were performed by using a 3 Tesla (T) MRI scanner with an 8 channel Rabbit coil. The chemical metabolites were identified by LC Model including N-acetylaspartate (NAA), creatine (Cr), glutamate (Glu), glutamine (Gln), Glycerophosphatidylcholine (GPC), phosphorylcholine (PCH), and myoinositol (MI). The relative concentrations (/Cr) were analyzed. Additionally, Amyloid-ß (Aß) accumulation in the brain was measured postmortem. For comparisons of MR and Aß data between groups, two-tailed t-tests were performed. RESULTS: The ratio of NAA/Cr (0.76 ± 0.10) and Glu/Cr (0.90 ± 0.14) in group CD were lower than those in the group NC (0.87 ± 0.06, 1.13 ± 0.22, respectively, P <  0.05). Compared to the group NC (2.88 ± 0.09 cm3, 0.63 ± 0.08 cm3, respectively), the cortical and hippocampal volumes (2.60 ± 0.14 cm3 and 0.47 ± 0.07 cm3, respectively) of rabbits brain decreased in the group CD while the third and lateral ventricular volumes enlarged (44.56 ± 6.01 mm3 vs 31.40 ± 6.14 mm3, 261.40 ± 30.98 mm3 vs 153.81 ± 30.08 mm3, P <  0.05). These metabolic and structural changes were additionally accompanied by the significant increase of Aß1-42 in the cortex and hippocampus (163.60 ± 16.26 pg/mg and 215.20 ± 69.86 pg/mg, respectively, P <  0.05). CONCLUSION: High cholesterol diet can induce the brain metabolic and structural changes of the rabbit including lowered level of NAA and Glu and the atrophy of the brain which were similar to those of human AD.

GENERAL CONTROL NONREPRESSED PROTEIN5-Mediated Histone Acetylation of FERRIC REDUCTASE DEFECTIVE3 Contributes to Iron Homeostasis in Arabidopsis.

Iron homeostasis is essential for plant growth and development. Here, we report that a mutation in GENERAL CONTROL NONREPRESSED PROTEIN5 (GCN5) impaired iron translocation from the root to the shoot in Arabidopsis (Arabidopsis thaliana). Illumina high-throughput sequencing revealed 879 GCN5-regulated candidate genes potentially involved in iron homeostasis. Chromatin immunoprecipitation assays indicated that five genes (At3G08040, At2G01530, At2G39380, At2G47160, and At4G05200) are direct targets of GCN5 in iron homeostasis regulation. Notably, GCN5-mediated acetylation of histone 3 lysine 9 and histone 3 lysine 14 of FERRIC REDUCTASE DEFECTIVE3 (FRD3) determined the dynamic expression of FRD3. Consistent with the function of FRD3 as a citrate efflux protein, the iron retention defect in gcn5 was rescued and fertility was partly restored by overexpressing FRD3. Moreover, iron retention in gcn5 roots was significantly reduced by the exogenous application of citrate. Collectively, these data suggest that GCN5 plays a critical role in FRD3-mediated iron homeostasis. Our results provide novel insight into the chromatin-based regulation of iron homeostasis in Arabidopsis.

Effect of patchouli alcohol on the regulation of heat shock-induced oxidative stress in IEC-6 cells.

Purpose Patchouli alcohol (PA) is used to treat gastrointestinal dysfunction. The purpose of this study was to ascertain the function of PA in the regulated process of oxidative stress in rat intestinal epithelial cells (IEC-6). Materials and methods Oxidative stress was stimulated by exposing IEC-6 cells to heat shock (42 °C for 3 h). IEC-6 cells in treatment groups were pretreated with various concentrations of PA (10, 40, and 80 ng/mL) for 3 h before heat shock. Results Heat shock caused damage to the morphology of IEC-6 cells, and increased reactive oxygen species (ROS) level and malondialdehyde (MDA) content. Moreover, mRNA and protein expression by target genes related to oxidative stress in heat shock were also altered. Specifically, the mRNA expression by HSP70, HSP90, GSH-px, NRF2 nd HO-1were all increased, and Nrf2 and Keap1 protein expression were increased after heat shock. However, pretreatment with PA weakened the level of damage to the cellular morphology, and decreased the MDA content caused by heat shock, indicating PA had cytoprotective activities. Pretreatment with PA at high dose significantly increased generation of intracellular ROS. Compared with the heat shock group alone, PA pretreatment significantly decreased the mRNA expression by HSP70, HSP90, SOD, CAT, GSH-px, KEAP1 and HO-1. Furthermore, the high dose of PA significantly increased Nrf2 protein expression, while both the intermediate and high dose of PA significantly increased HO-1 protein expression. Conclusion Heat-shock-induced oxidative stress in IEC-6 cells, and PA could alleviate the Nrf2-Keap1 cellular oxidative stress responses.

Transport stress induces apoptosis in rat myocardial tissue via activation of the mitogen-activated protein kinase signaling pathways.

The present study aimed to elucidate the mechanism of myocardial damage induced by simulated transport stress. Sprague-Dawley rats were subjected to 35 °C and 60 rpm (0.1×g rcf) on a constant temperature shaker. The blood samples were prepared for detection of epinephrine (E), norepinephrine (NE), atrial natriuretic peptide (ANP), brain natriuretic peptide (BNP) and serum cardiac troponin T (cTNT); myocardium samples were prepared for morphological examination and signaling protein quantitative. The result showed that plasma norepinephrine (NE) and epinephrine (E) concentrations increased in all stressed groups (P < 0.01). Levels of serum cardiac troponin T (cTNT) were elevated in both the S2d (P < 0.05) and S3d groups (P < 0.01). The concentration of plasma BNP was increased significantly in S3d group (P < 0.05); the difference in ANP was not remarkable. Morphological observation demonstrated obvious microstructure and ultrastructure damage after simulated transport stress. There was also a significant increase in the number of TUNEL-positive cardiomyocytes in stressed hearts. Western blot analysis found that the mitogen-activated protein kinase (MAPK) pathways were activated by strengthening phosphorylation of ASK-1, JNK, P38 and ERK in rat myocardial tissue after simulated transport stress (P < 0.05, P < 0.01). In addition, the ratio of pro-apoptotic Bax and anti-apoptotic Bcl-2 proteins was increased in stressed rats (P < 0.01), and the amount of cleaved-caspase3 increased in all stressed rats (P < 0.01). The expression of cleaved-caspase9 protein was also elevated in S2d and S3d groups (P < 0.01). Consequently simulated transport stress induced obvious myocardial damage, which may be attributed to the activation of caspase 9-mediated mitochondrial apoptotic pathway and MAPK pathways.

Sodium tanshinone IIA sulfonate affects Marek's disease virus replication by inhibiting gB expression.

CONTEXT: Previous studies demonstrated that sodium tanshinone IIA sulfonate (STS) could inhibit MDV replication in vitro. The mechanism about how STS inhibits MDV replication is still not well understood. OBJECTIVE: In this study, we evaluated the effect of STS on gB gene/protein of Marek's disease virus (MDV). MATERIALS AND METHODS: The concentration of 0.25 mg/ml of STS was used in this study. Meanwhile, 0.25 mg/ml of acyclovir (ACV) was used as a positive control. About 9-11-d-old embryonated specific-pathogen-free (SPF) chicken eggs were used to prepare CEF cells. CEF cells were infected with MDV 2 h, followed by treatment with STS. Real-time PCR and western blot assay were used to measure the gB (UL27) gene/protein expression in STS treatment group at 24, 48, 72, and 96 h post-infection. RESULTS: Compared with MDV control, the gB gene copies were significantly decreased in STS and ACV treatment groups at 72 h and 96 h (p < 0.05), both in the DNA and in the mRNA level. Furthermore, the expression of gB protein was also inhibited by STS at 24, 72, and 96 h. DISCUSSION AND CONCLUSION: Our study demonstrated that STS could effectively inhibit the MDV replication by suppressing gB gene/protein expression in cell culture.

Punicalagin Induces Nrf2/HO-1 Expression via Upregulation of PI3K/AKT Pathway and Inhibits LPS-Induced Oxidative Stress in RAW264.7 Macrophages.

Reactive oxygen species (ROS) and oxidative stress are thought to play a central role in potentiating macrophage activation, causing excessive inflammation, tissue damage, and sepsis. Recently, we have shown that punicalagin (PUN) exhibits anti-inflammatory activity in LPS-stimulated macrophages. However, the potential antioxidant effects of PUN in macrophages remain unclear. Revealing these effects will help understand the mechanism underlying its ability to inhibit excessive macrophage activation. Hemeoxygenase-1 (HO-1) exhibits antioxidant activity in macrophages. Therefore, we hypothesized that HO-1 is a potential target of PUN and tried to reveal its antioxidant mechanism. Here, PUN treatment increased HO-1 expression together with its upstream mediator nuclear factor-erythroid 2 p45-related factor 2 (Nrf2). However, specific inhibition of Nrf2 by brusatol (a specific Nrf2 inhibitor) dramatically blocked PUN-induced HO-1 expression. Previous research has demonstrated that the PI3K/Akt pathway plays a critical role in modulating Nrf2/HO-1 protein expression as an upstream signaling molecule. Here, LY294002, a specific PI3K/Akt inhibitor, suppressed PUN-induced HO-1 expression and led to ROS accumulation in macrophages. Furthermore, PUN inhibited LPS-induced oxidative stress in macrophages by reducing ROS and NO generation and increasing superoxide dismutase (SOD) 1 mRNA expression. These findings provide new perspectives for novel therapeutic approaches using antioxidant medicines and compounds against oxidative stress and excessive inflammatory diseases including tissue damage, sepsis, and endotoxemic shock.

[Experimental research on the prevention of rabbit postoperative abdominal cavity adhesion with PLGA membrane].

The aim of this paper is to explore the prevention of rabbit postoperative abdominal cavity adhesion with poly (lactic-co-glycotic acid) (PLGA) membrane and the mechanism of this prevention function. Sixty-six Japanese white rabbits were randomly divided into normal control group, model control group and PLGA membrane group. The rabbits were treated with multifactor methods to establish the postoperative abdominal cavity adhesion models except for those in the normal control group. PLGA membrane was used to cover the wounds of rabbits in the PLGA membrane group and nothing covered the wounds of rabbits in the model control group. The hematologic parameters, liver and kidney functions and fibrinogen contents were detected at different time. The rabbit were sacrificed 1, 2, 4, 6, 12 weeks after the operations, respectively. The adhesions were graded blindly, and Masson staining and immunohistochemistry methods were used to observe the proliferation of collagen fiber and the expression of transforming growth factor ß1 (TGF-ß1) on the cecal tissues, respectively. The grade of abdominal cavity adhesion showed that the PLGA membrane-treated group was significant lower than that in the model control group, and it has no influence on liver and kidney function and hematologic parameters. But the fibrinogen content and the number of white blood cell in the PLGA membrane group were significant lower than those of model control group 1 week and 2 weeks after operation, respectively. The density of collagen fiber and optical density of TGF-ß1 in the PLGA membrane group were significant lower than those of model control group. The results demonstrated that PLGA membrane could be effective in preventing the abdominal adhesions in rabbits, and it was mostly involved in the reducing of fibrinogen exudation, and inhibited the proliferation of collagen fiber and over-expression of TGF-ß1.

The protective effect of caffeic acid against inflammation injury of primary bovine mammary epithelial cells induced by lipopolysaccharide.

Caffeic acid possesses multiple biological effects, such as antibacterial, antioxidant, antiinflammatory, and anticancer growth; however, what effects it has on bovine mastitis have not been investigated. The aim of this study was to verify the antiinflammatory properties of caffeic acid on the inflammatory response of primary bovine mammary epithelial cells (bMEC) induced by lipopolysaccharide (LPS), and to clarify the possible underlying mechanism. Bovine mammary epithelial cells were treated with various concentrations (10, 50, 100, and 200 µg/mL) of LPS for 3, 6, 12, and 18 h; the results showed that LPS significantly inhibited cell viability in a time- and dose-dependent manner. When cells were treated with LPS (50 µg/mL) for 12h, the cell membrane permeability significantly increased, which promoted cell apoptosis. Various concentrations (10, 25, and 50 µg/mL) of caffeic acid could weaken the inflammation injury of bMEC induced by LPS without cytotoxicity. Proinflammatory cytokines (IL-8, IL-1ß, IL-6, and tumor necrosis factor α) from bMEC were decreased. Nuclear transcription factor κB activity was weakened via blocking κB inhibitor α degradation and p65 phosphorylation. All these showed that the protective effect of caffeic acid on LPS-induced inflammation injury in bMEC was at least partly achieved by the decreased production of proinflammatory cytokines mediated by the effect of reducing the κB inhibitor α degradation and p65 phosphorylation in the nuclear transcription factor κB pathway. The use of caffeic acid would be beneficial in dairy cows during Escherichia coli mastitis as a safe and natural antiinflammatory drug.

[Effects of PLGA absorbable membrane on preventing postoperative abdominal adhesion in rabbits].

OBJECTIVE: To investigate the effects of PLGA absorbable membrane in prevention of postoperative abdominal adhesion in rabbits. METHODS: 66 Japanese white rabbits were randomly divided into three groups: the normal control group n = 6, model control group n = 30 and PLGA group n = 30. Rabbits were received multifactor methods to establish postoperative abdominal adhesion models except for normal control group. The cecum wound was covered PLGA membrane in the PLGA group. At postoperative 1, 2, 4, 6 and 12 weeks, the abdominal cavities were reopened and the adhesive severity was graded blindly, and the hydroxyproline level in cecum tissue was measured and the cecum histopathology was observed. RESULTS: (1) the degree of adhesion and hydroxyproline level in model control group were significantly higher than those of normal control group (P < 0.05, P < 0.01), while the degree of adhesion and hydroxyproline level in PLGA group were significantly lower than those of model control group (P < 0.05). (2) HE staining showed that cecum serosa had obviously inflammatory cell infiltration and fibroblast proliferation, while PLGA could inhibit fibroblast proliferation and reduce the inflammatory cell infiltration and collagen. CONCLUSION: PLGA absorbable membrane can inhibit fibroblast proliferation and collagen to prevent the experimental postoperative peritoneal adhesions.

Involvement of oxidative stress and mitogen-activated protein kinase signaling pathways in heat stress-induced injury in the rat small intestine.

Extreme heat stress-induced gastrointestinal injury and dysfunction may occur during summer. We investigated possible mechanisms of heat stress-induced damage in the small intestine using male Sprague-Dawley rats subjected to 2 h of heat stress (40 °C, 60% relative humidity) daily for 10 consecutive days. Rats were killed at specific times immediately following heat treatment to determine: morphological changes by optical and electron microscopy; intestinal permeability using fluorescein isothiocyanate-dextran; production of reactive oxygen species (ROS), malondialdehyde (MDA), and activities of superoxide-dismutase and glutathione-peroxidase by specific assays; phosphorylation of extracellular signal-regulated kinase 1/2 (ERK1/2), c-Jun N-terminal kinase (JNK), and p38 mitogen-activated protein kinase (MAPK) by immunocytochemistry and western-blot analysis. The rat intestinal epithelial cell line (IEC-6) and specific MAPK inhibitors were used for in vitro investigation of effects of activation of MAPKs by heat stress. Heat stress caused marked morphological damage to the small intestine and significantly increased intestinal permeability. Heat stress increased ROS and MDA production, and significantly reduced anti-oxidase activity. MAPK activity in small intestine was increased by heat stress. In vitro, heat stress caused damage and apoptosis in IEC-6 cells; inhibition of ERK1/2 activation (by U0126) exacerbated these effects, which were attenuated by inhibition of JNK (by SP600125) and p38 (by SB203580) activation. Hence, heat stress caused severe small intestine injury, increased oxidative stress, and activated MAPK signaling pathways. The in vitro studies indicated that ERK1/2 activation is anti-apoptotic, and JNK and p38 activation are pro-apoptotic in heat stressed intestinal epithelial cells.

Inhibition of heat-induced apoptosis in rat small intestine and IEC-6 cells through the AKT signaling pathway.

BACKGROUND: As the world warms up, heat stress is becoming a major cause of economic loss in the livestock industry. Long-time exposure of animals to hyperthermia causes extensive cell apoptosis, which is harmful to them. AKT and AKT-related serine-threonine kinases are known to be involved in signaling cascades that regulate cell survival, but the mechanism remains elusive. In the present study, we demonstrate that phosphoinositide 3-kinase (PI3K) /AKT signal pathway provides protection against apoptosis induced by heat stress to ascertain the key point for treatment. RESULTS: Under heat stress, rats showed increased shedding of intestinal epithelial cells. These rats also had elevated levels of serum cortisol and improved expression of heat shock proteins (Hsp27, Hsp70 and Hsp90) in response to heat stress. Apoptosis analysis by TUNEL assay revealed a higher number of villi epithelial cells that were undergoing apoptosis in heat-treated rats than in the normal control. This is supported by gene expression analysis, which showed an increased ratio of Bax/Bcl-2 (p < 0.05), an important indicator of apoptosis. During heat-induced apoptosis, more AKTs were activated, showing increased phosphorylation. An increase of BAD phosphorylation, which is an inhibitory modification, ensued. In rat IEC-6 cell line, a significant higher level of AKT phosphorylation was observed at 2 h after heat exposure. This coincided with a marked reduction of apoptosis. CONCLUSION: Together, these results suggest that heat stress caused damages to rat jejunum and induced apoptosis to a greater degree. HSPs and pro-survival factors were involved in response to heat stress. Among them, AKT played a key role in inhibiting heat-induced apoptosis.

Role of prostaglandin E2 in macrophage polarization: Insights into atherosclerosis.

Atherosclerosis, a trigger of cardiovascular disease, poses grave threats to human health. Although atherosclerosis depends on lipid accumulation and vascular wall inflammation, abnormal phenotypic regulation of macrophages is considered the pathological basis of atherosclerosis. Macrophage polarization mainly refers to the transformation of macrophages into pro-inflammatory (M1) or anti-inflammatory (M2) phenotypes, which has recently become a much-discussed topic. Increasing evidence has shown that M2 macrophage polarization can alleviate atherosclerosis progression. PGE2 is a bioactive lipid that has been observed to be elevated in atherosclerosis and to play a pro-inflammatory role, yet recent studies have reported that PGE2 promotes anti-inflammatory M2 macrophage polarization and mitigates atherosclerosis progression. However, the mechanisms by which PGE2 acts remain unclear. This review summarizes current knowledge of PGE2 and macrophages in atherosclerosis. Additionally, we discuss potential PGE2 mechanisms of macrophage polarization, including CREB, NF-κB, and STAT signaling pathways, which may provide important therapeutic strategies based on targeting PGE2 pathways to modulate macrophage polarization for atherosclerosis treatment.

Reduction of intestinal mucosal immune function in heat-stressed rats and bacterial translocation.

PURPOSE: The aim of this study was to further understand the effects and mechanism of heat stress on the intestinal mucosal immune system of the rat, including changes in the intestinal mucosal barrier and immune function and their effects on bacterial translocation. MATERIALS AND METHODS: Sprague Dawley (SD) rats were randomly divided into control and heat-stress groups. Both groups were housed in a 25°C environment of 60% relative humidity. The heat-stress group was subjected to 40°C for 2 h daily over 3 days. RESULTS: Compared with the control group villi length in the small intestines of the heat-stress group was shortened. Jejunal mucosa were seriously damaged and the number of goblet cells in the epithelia of the duodenum and jejunum was significantly reduced. Electron microscopy revealed intestinal mucosal disorder, a large number of exudates of inflammatory fibrous material, fuzzy tight junction structure between epithelial cells, and cell gap increases in the heat-stress group. Transcription of IFN-γ, IL-2, IL-4, and IL-10, was significantly reduced, as was that of the intestinal mucosal immune-related proteins TLR2, TLR4, and IgA. The number of CD3(+) T cells and CD3(+)CD4(+)CD8(-) T cells in the mesenteric lymph nodes (MLNs) was significantly lower, while the number of CD3(+)CD4(-)CD8(+) T cells was significantly increased. The bacteria isolated from the MLNs were Escherichia coli. CONCLUSIONS: Heat stress damages rat intestinal mechanical and mucosal immune barriers, and reduces immune function of the intestinal mucosa and mesenteric lymphoid tissues, leading to bacterial translocation.

Identification of Quantitative Trait Loci Associated With Iron Deficiency Tolerance in Maize.

Iron (Fe) is a limiting factor in crop growth and nutritional quality because of its low solubility. However, the current understanding of how major crops respond to Fe deficiency and the genetic basis remains limited. In the present study, Fe-efficient inbred line Ye478 and Fe-inefficient inbred line Wu312 and their recombinant inbred line (RIL) population were utilized to reveal the physiological and genetic responses of maize to low Fe stress. Compared with the Fe-sufficient conditions (+Fe: 200 µM), Fe-deficient supply (-Fe: 30 µM) significantly reduced shoot and root dry weights, leaf SPAD of Fe-efficient inbred line Ye478 by 31.4, 31.8, and 46.0%, respectively; decreased Fe-inefficient inbred line Wu312 by 72.0, 45.1, and 84.1%, respectively. Under Fe deficiency, compared with the supply of calcium nitrate (N1), supplying ammonium nitrate (N2) significantly increased the shoot and root dry weights of Wu312 by 37.5 and 51.6%, respectively; and enhanced Ye478 by 23.9 and 45.1%, respectively. Compared with N1, N2 resulted in a 70.0% decrease of the root Fe concentration for Wu312 in the -Fe treatment, N2 treatment reduced the root Fe concentration of Ye478 by 55.8% in the -Fe treatment. These findings indicated that, compared with only supplying nitrate nitrogen, combined supply of ammonium nitrogen and nitrate nitrogen not only contributed to better growth in maize but also significantly reduced Fe concentration in roots. In linkage analysis, ten quantitative trait loci (QTLs) associated with Fe deficiency tolerance were detected, explaining 6.2-12.0% of phenotypic variation. Candidate genes considered to be associated with the mechanisms underlying Fe deficiency tolerance were identified within a single locus or QTL co-localization, including ZmYS3, ZmPYE, ZmEIL3, ZmMYB153, ZmILR3 and ZmNAS4, which may form a sophisticated network to regulate the uptake, transport and redistribution of Fe. Furthermore, ZmYS3 was highly induced by Fe deficiency in the roots; ZmPYE and ZmEIL3, which may be involved in Fe homeostasis in strategy I plants, were significantly upregulated in the shoots and roots under low Fe stress; ZmMYB153 was Fe-deficiency inducible in the shoots. Our findings will provide a comprehensive insight into the physiological and genetic basis of Fe deficiency tolerance.

Mapping of the Quantitative Trait Loci and Candidate Genes Associated With Iron Efficiency in Maize.

Iron (Fe) is a mineral micronutrient for plants, and Fe deficiency is a major abiotic stress in crop production because of its low solubility under aerobic and alkaline conditions. In this study, 18 maize inbred lines were used to preliminarily illustrate the physiological mechanism underlying Fe deficiency tolerance. Then biparental linkage analysis was performed to identify the quantitative trait loci (QTLs) and candidate genes associated with Fe deficiency tolerance using the recombinant inbred line (RIL) population derived from the most Fe-efficient (Ye478) and Fe-inefficient (Wu312) inbred lines. A total of 24 QTLs was identified under different Fe nutritional status in the Ye478 × Wu312 RIL population, explaining 6.1-26.6% of phenotypic variation, and ten candidate genes were identified. Plants have evolved two distinct mechanisms to solubilize and transport Fe to acclimate to Fe deficiency, including reduction-based strategy (strategy I) and chelation-based strategy (strategy II), and maize uses strategy II. However, not only genes involved in Fe homeostasis verified in strategy II plants (strategy II genes), which included ZmYS1, ZmYS3, and ZmTOM2, but also several genes associated with Fe homeostasis in strategy I plants (strategy I genes) were identified, including ZmFIT, ZmPYE, ZmILR3, ZmBTS, and ZmEIN2. Furthermore, strategy II gene ZmYS1 and strategy I gene ZmBTS were significantly upregulated in the Fe-deficient roots and shoots of maize inbred lines, and responded to Fe deficiency more in shoots than in roots. Under Fe deficiency, greater upregulations of ZmYS1 and ZmBTS were observed in Fe-efficient parent Ye478, not in Fe-inefficient parent Wu312. Beyond that, ZmEIN2 and ZmILR3, were found to be Fe deficiency-inducible in the shoots. These findings indicate that these candidate genes may be associated with Fe deficiency tolerance in maize. This study demonstrates the use of natural variation to identify important Fe deficiency-regulated genes and provides further insights for understanding the response to Fe deficiency stress in maize.