Calreticulin (CALR) promotes ionophore-induced microneme secretion in Toxoplasma gondii.

The flow of calcium ions (Ca2+) is involved in numerous vital activities of Toxoplasma gondii. Calreticulin is a type of Ca2+-binding protein in the endoplasmic reticulum (ER) that is involved in Ca2+ signaling pathway regulation, Ca2+ storage, and protein folding. In this work, the calreticulin (CALR), a protein predicted to possess a conserved domain of calreticulin in T. gondii, was characterized. The CALR localized in the ER. Using reverse genetics, we discovered that CALR is not necessary for the lytic cycle, including invasion and replication. However, depletion of CALR affected microneme secretion triggered by A23187, which is a Ca2+ ionophore used to increase cytoplasmic Ca2+ concentration. Furthermore, we discovered that CALR influences Ca2+ release. Transcriptomic comparison between Δcalr and Δku80 parasites showed that 226 genes in the Δcalr parasites were significantly downregulated (p < 0.05). The cellular biological functions of the downregulated genes were mainly involved in calmodulin-dependent protein kinase pathways. Furthermore, in the absence of CALR, tachyzoites were still able to cause acute infection in mice. These results imply that by influencing ER Ca2+ release content, CALR may further impair the ionophore-induced secretion of the parasite. However, this protein is not required for the completion of the parasite's lytic cycle or for the acute virulence of the parasite.

Identification of specific antigens between Toxoplasma gondii and Neospora caninum and application of potential diagnostic antigen TgGRA54.

Toxoplasma gondii is a zoonotic parasite that is very common in livestock. Meat products from livestock infected with T. gondii are one of the important transmission routes of toxoplasmosis. Rapid and reliable diagnosis is a prerequisite for the prevention and control of toxoplasmosis. Neospora caninum and T. gondii are similar in morphology and life history, and there are a large number of cross antigens between them, making clinical diagnosis of toxoplasmosis more difficult. In this study, immunoprecipitation-mass spectrometry (IP-MS) was used to screen for T. gondii-specific antigens, and the specific antigen was cloned and expressed in Escherichia coli. The specific antigen was then used to establish an indirect ELISA diagnostic method. A total of 241 specific antigens of T. gondii and 662 cross antigens between T. gondii and N. caninum were screened by IP-MS. Through bioinformatics analysis and homology comparison, seven proteins were selected for gene cloning and prokaryotic expression, and the most suitable antigen, TgGRA54, was selected to establish an indirect ELISA for T. gondii. Compared with the indirect immunofluorescent antibody test (IFAT), the positive coincidence rate of the ELISA based on rTgGRA54 was 100% (72/72) and the negative coincidence rate was 80.95% (17/21). The indirect ELISA method based on TgGRA54 recombinant protein was established to detect T. gondii antibodies in bovine sera, and the recombinant protein reacted well with T. gondii positive sera from sheep, mouse, and swine, indicating that the recombinant protein is a good diagnostic antigen for T. gondii.

Function of Neospora caninum dense granule protein 7 in innate immunity in mice.

The intracellular parasite Neospora caninum can parasitize all nucleated cells of the host. Dense granule proteins (GRAs) secreted by dense granules are an important material involved in the formation of parasitophorous vacuoles (PVs), which facilitate parasite survival and replication in host cells. Due to the secretory and immune properties of NcGRA7, it is considered to be a promising serodiagnosis marker and an effective neosporosis vaccine candidate. However, the intracellular regulatory mechanisms involved in NcGRA7-induced host responses have rarely been examined. Here, we used the CRISPR/Cas9 genome editing system to obtain a NcGRA7 knockout strain (ΔNcGRA7) and a NcGRA7 complementary strain (iΔNcGRA7) to study their function. We found that ΔNcGRA7 exhibited slower growth in vitro and weakened virulence in mice compared with Nc1 and iΔNcGRA7. All parasite strains can stimulate host immune cells to produce IFN-γ, and the amount of IFN-γ production stimulated by Nc1 was significantly higher than that stimulated by ΔNcGRA7. The transcription levels of the cellular immune factors GBP1, GBP2, IRGa6, and IRGb6 were significantly higher after stimulation with ΔNcGRA7 parasites than after stimulation with Nc1. Furthermore, ΔNcGRA7 infection resulted in greater IRGa6 recruitment to the PVM than Nc1 infection. ΔNcGRA7 parasites were more easily cleared by macrophages than Nc1 parasites. Collectively, these results showed that NcGRA7 plays an important role in regulating the immune factors of mice and the aggregation of IRGa6 at the PVM, which affects the pathogenicity of N. caninum.

Long noncoding RNA MALAT1 promotes high glucose-induced human endothelial cells pyroptosis by affecting NLRP3 expression through competitively binding miR-22.

Cell death and inflammation play critical roles in atherosclerosis. Pyroptosis, a novel proinflammatory programmed cell death process, participates in atherosclerosis pathogenesis. Recently, MALAT1 was identified as a pyroptosis-related long noncoding RNA (lncRNA). Here, we investigated the potential role and underlying mechanism of lncRNA MALAT1 in endothelial cells pyroptosis. We first established an endothelial cell pyroptosis model by stimulating EA.hy926 human endothelial cells (EA.hy926 cells) with high glucose. Then, we investigated lncRNA MALAT1 expression and found that it was upregulated in high glucose-treated EA.hy926 cells. Furthermore, lncRNA MALAT1 knockdown significantly inhibited high glucose-induced pyroptosis in EA.hy926 cells, which may critically influence atherosclerosis. Moreover, miR-22 was a target of lncRNA MALAT1 and was negatively correlated with lncRNA MALAT1. NLRP3 expression was significantly suppressed by transfection with a MALAT1-targeting antisense oligonucleotide (ASO). Ultimately, miR-22 overexpression abrogated the effect of MALAT1 on high glucose-induced EA.hy926 cells pyroptosis. Together, our results suggest that lncRNA MALAT1 promotes high glucose-induced pyroptosis of endothelial cells partly by affecting NLRP3 expression through competitively binding miR-22. Our findings indicate a new regulatory mechanism for endothelial cells pyroptosis under high-glucose stress, providing a novel therapeutic target for atherosclerosis.

MicroRNA-99a inhibits insulin-induced proliferation, migration, dedifferentiation, and rapamycin resistance of vascular smooth muscle cells by inhibiting insulin-like growth factor-1 receptor and mammalian target of rapamycin.

Patients with type 2 diabetes mellitus (T2DM) are characterized by insulin resistance and are subsequently at high risk for atherosclerosis. Hyperinsulinemia has been associated with proliferation, migration, and dedifferentiation of vascular smooth muscle cells (VSMCs) during the pathogenesis of atherosclerosis. Moreover, insulin-like growth factor-1 receptor (IGF-1R) and mammalian target of rapamycin (mTOR) have been demonstrated to be the underlying signaling pathways. Recently, microRNA-99a (miR-99a) has been suggested to regulate the phenotypic changes of VSMCs in cancer cells. However, whether it is involved in insulin-induced changes of VSCMs has not been determined. In this study, we found that insulin induced proliferation, migration, and dedifferentiation of mouse VSMCs in a dose-dependent manner. Furthermore, the stimulating effects of high-dose insulin on proliferation, migration, and dedifferentiation of mouse VSMCs were found to be associated with the attenuation of the inhibitory effects of miR-99a on IGF-1R and mTOR signaling activities. Finally, we found that the inducing effect of high-dose insulin on proliferation, migration, and dedifferentiation of VSMCs was partially inhibited by an active mimic of miR-99a. Taken together, these results suggest that miR-99a plays a key regulatory role in the pathogenesis of insulin-induced proliferation, migration, and phenotype conversion of VSMCs at least partly via inhibition of IGF-1R and mTOR signaling. Our results provide evidence that miR-99a may be a novel target for the treatment of hyperinsulinemia-induced atherosclerosis.

One-Dimensional Zinc-Based Coordination Polymer as a Higher Capacity Anode Material for Lithium Ion Batteries.

A zinc-based one-dimensional (1D) coordination polymer ([Zn(H2mpca)2(tfbdc)(H2O)], Zn-ODCP) has been synthesized and characterized by spectroscopic and physicochemical methods, single-crystal X-ray diffraction, and thermogravimetric analysis (H2mpca = 3-methyl-1H-pyrazole-4-carboxylic acid; H2tfbdc = 2,3,5,6-tetrafluoroterephthalic acid). Zn-ODCP shows blue luminescence in the solid state. When Zn-ODCP acts as an anode material for lithium ion batteries, it exhibits a good cyclic stability and a higher reversible capacity of 300 mAh g-1 at 50 mA g-1 after 50 cycles. The higher capacity may be mainly ascribed to the metal ion and ligand all taking part in lithium storage. Searching for electrode materials of lithium ion batteries from 1D metal coordination polymers is a new route.

Gss deficiency causes age-related fertility impairment via ROS-triggered ferroptosis in the testes of mice.

Glutathione synthetase (GSS) catalyzes the final step in the synthesis of glutathione (GSH), a well-established antioxidant. Research on the specific roles of the Gss gene during spermatogenesis remains limited due to the intricate structure of testis. In this study, we identified pachytene spermatocytes as the primary site of GSS expression and generated a mouse model with postnatal deletion of Gss using Stra8-Cre (S8) to investigate the role of GSS in germ cells. The impact of Gss knockout on reducing male fertility is age-dependent and caused by ferroptosis in the testis. The 2-month-old S8/Gss-/- male mice exhibited normal fertility, due to a compensatory increase in GPX4, which prevented the accumulation of ROS. With aging, there was a decline in GPX4 and an increase in ALOX15 levels observed in 8-month-old S8/Gss-/- mice, resulting in the accumulation of ROS, lipid peroxidation, and ultimately testicular ferroptosis. We found that testicular ferroptosis did not affect spermatogonia, but caused meiosis disruption and acrosome heterotopia. Then the resulting aberrant sperm showed lower concentration and abnormal morphology, leading to reduced fertility. Furthermore, these injuries could be functionally rescued by inhibiting ferroptosis through intraperitoneal injection of GSH or Fer-1. In summary, Gss in germ cells play a crucial role in the resistance to oxidative stress injury in aged mice. Our findings deepen the understanding of ferroptosis during spermatogenesis and suggest that inhibiting ferroptosis may be a potential strategy for the treatment of male infertility.

Microneme Protein 6 Is Involved in Invasion and Egress by Neospora caninum.

BACKGROUND: Neospora caninum, is the etiological agent of neosporosis, an infection that causes abortions in cattle and nervous system dysfunction in dogs. Invasion and egress are the key steps of the pathogenesis of N. caninum infection. Microneme proteins (MICs) play important roles in the recognition, adhesion, and invasion of host cells in other apicomplexan parasites. However, some MICs and their functions in N. caninum infection have rarely been reported. METHODS: The homologous recombination strategy was used to investigate the function of MIC6 in N. caninum infection. RESULTS: ΔNcMIC6 showed a smaller plaque size and weakened capacities of invasion and egress than Nc1. Transcription levels of the egress-related genes CDPK1, PLP1, and AMA1 of ΔNcMIC6 were downregulated. Due to the lack of NcMIC6, virulence of the pathogen in the infected mouse was weakened. The subcellular localization of NcMIC1 and NcMIC4 in ΔNcMIC6, however, did not change. Nevertheless, the transcription levels of MIC1 and MIC4 in ΔNcMIC6 were downregulated, and the expression and secretion of MIC1 and MIC4 in ΔNcMIC6 were reduced compared with that in Nc1. Furthermore, the absence of NcMIC6 weakened the virulence in mice and lower parasite load detected in mice brains. CONCLUSIONS: NcMIC6 is involved in host cell invasion and egress in N. caninum and may work synergistically with other MICs to regulate the virulence of the pathogen. These data lay a foundation for further research into the function and application of NcMIC6.

Fenofibrate Improves Insulin Resistance and Hepatic Steatosis and Regulates the Let-7/SERCA2b Axis in High-Fat Diet-Induced Non-Alcoholic Fatty Liver Disease Mice.

Fenofibrate is widely used in clinical therapy to effectively ameliorate the development of non-alcoholic fatty liver disease (NAFLD); however, its specific molecular mechanism of action remains largely unknown. MicroRNAs (miRNAs) are key mediators in regulating endoplasmic reticulum (ER) stress during NAFLD, and the deregulation of miRNAs has been demonstrated in NAFLD pathophysiology. The present study aimed to identify whether fenofibrate could influence miRNA expression in NAFLD and investigate the specific mechanism of action of fenofibrate in lipid metabolism disorder-associated diseases. We found that fenofibrate alleviated ER stress and increased the levels of SERCA2b, which serves as a regulator of ER stress. Additionally, the levels of let-7 miRNA were regulated by fenofibrate; let-7 was found to target the 3' untranslated region of SERCA2b. The present data suggest that the protective effects of fenofibrate against insulin resistance and its suppressive activity against excessive hepatic lipid accumulation may be related to the alteration of the let-7/SERCA2b axis and alleviation of ER stress.

The effect of the expression of angiotensin II on extracellular matrix metalloproteinase inducer (EMMPRIN) in macrophages is mediated via the AT1/COX-2/PGE2 pathway.

AIM: To explore the expression of extracellular matrix metalloproteinase inducer (EMMPRIN) in THP-1 macrophages induced by angiotensin II (Ang II) and the mechanism of EMMPRIN expression. METHODS: THP-1 cells were cultured and induced into macrophages, then stimulated with 10(-6) mol/L Ang II. Levels of EMMPRIN gene and its protein were measured by real-time polymerase chain reaction and western blotting. Prostaglandin E(2) (PGE(2)) expression was assayed by enzyme-linked immunosorbent assay. Antagonists of the angiotensin type-1 receptor (AT(1)R) and angiotensin type-2 receptor (AT(2)R) were used to inhibit the effect of Ang II, and PGE(2) added to detail the mechanism of Ang II-induced EMMPRIN expression. RESULTS: Ang II clearly induced the expression of EMMPRIN mRNA and protein in macrophages; this expression peaked at 12 h and declined after 24 h. The tendency of enhancement of the levels of cyclooxygenase-2 (COX-2) and PGE(2) was coincident with EMMPRIN expression. AT(1)-receptor antagonists and COX-2 inhibitors inhibited the effect of Ang II, but AT(2)-receptor antagonists did not. CONCLUSION: Ang II can up-regulate EMMPRIN expression in THP-1 macrophages via the AT(1)/COX-2/PGE(2) signal transduction pathway, and the effect can be inhibited by losartan and NS-398.

Characterization of Neospora Caninum Microneme Protein 26 and Its Potential Use as a Diagnostic Marker for Neosporosis in Cattle.

The apicomplexan parasite Neospora caninum causes neosporosis, an illness that leads to abortion or stillbirth in cattle, causing massive economic losses to the livestock industry. Rapid and viable diagnosis is the premise of prevention and control for neosporosis. In this study, we screened a new microneme protein 26 (NcMIC26) through western blot and mass spectrometry identification from the excretory secretion antigen (ESA) of N. caninum tachyzoites. NcMIC26 is subcellularly localized to the microneme of parasites. NcMIC26 is a specific antigen of N. caninum and has no cross-reaction with Toxoplasma gondii. Therefore, NcMIC26 has the potential to be a candidate diagnostic antigen for neosporosis. To test this hypothesis, recombinant NcMIC26 (rNcMIC26) was expressed in Escherichia coli (E. coli), and an indirect ELISA for detecting anti-N. caninum antibodies in cattle was established. Compared with that of the indirect immunofluorescent antibody test (IFAT), the positive coincidence rate of the ELISA based on rNcMIC26 was 76.53% (75/98), which was higher than that of an ELISA based on rSRS2 (66.33%), and the negative coincidence rate was 84.62% (33/39). It is noteworthy that 30 positive samples confirmed by IFAT were consistent with the rNcMIC26 ELISA but were negative by the rNcSRS2 ELISA. Our research illustrated that NcMIC26 is a dependable diagnostic marker for the serodiagnosis of N. caninum infection in cattle and could be utilized as a supplementary antigen for missed detection by NcSRS2.

Functional characterization of acyl-CoA binding protein in Neospora caninum.

BACKGROUND: Lipid metabolism is pivotal for the growth of apicomplexan parasites. Lipid synthesis requires bulk carbon skeleton acyl-CoAs, the transport of which depends on the acyl-CoA binding protein (ACBP). In Neospora caninum, the causative agent of neosporosis, the FASII pathway is required for growth and pathogenicity. However, little is known about the fatty acid transport mechanism in N. caninum. METHODS: We have identified a cytosolic acyl-CoA binding protein, with highly conserved amino acid residues and a typical acyl-CoA binding domain in N. caninum. The recombinant NcACBP protein was expressed to verify the binding activities of NcACBP in vitro, and the heterologous expression of NcACBP in Δacbp yeast in vivo. Lipid extraction from ΔNcACBP or the wild-type of N. caninum was analyzed by GC-MS or TLC. Furthermore, transcriptome analysis was performed to compare the gene expression in different strains. RESULTS: The NcACBP recombinant protein was able to specifically bind acyl-CoA esters in vitro. A yeast complementation assay showed that heterologous expression of NcACBP rescued the phenotypic defects in Δacbp yeast, indicating of the binding activity of NcACBP in vivo. The disruption of NcACBP did not perturb the parasite's growth but enhanced its pathogenicity in mice. The lipidomic analysis showed that disruption of NcACBP caused no obvious changes in the overall abundance and turnover of fatty acids while knockout resulted in the accumulation of triacylglycerol. Transcriptional analysis of ACBP-deficient parasites revealed differentially expressed genes involved in a wide range of biological processes such as lipid metabolism, posttranslational modification, and membrane biogenesis. CONCLUSIONS: Our study demonstrated that genetic ablation of NcACBP did not impair the survival and growth phenotype of N. caninum but enhanced its pathogenicity in mice. This deletion did not affect the overall fatty acid composition but modified the abundance of TAG. The loss of NcACBP resulted in global changes in the expression of multiple genes. This study provides a foundation for elucidating the molecular mechanism of lipid metabolism in N. caninum.

Rhodomyrtus tomentosa (Aiton.): A review of phytochemistry, pharmacology and industrial applications research progress.

Rhodomyrtus tomentosa (Aiton) is a flowering plant native to southern and southeastern Asia. Up to date, 106 chemical constituents have been isolated and identified from R. tomentosa. Among these compounds, triterpenoids, flavonoids, phenols and meroterpenoids are the major constituents. Investigations of pharmacological activities of R. tomentosa revealed that this edible medicinal herb exhibits a wide range of therapeutic potential including antibacterial, antitumor, anti-inflammatory and antioxidant activities both in vivo and in vitro. The purpose of this review is to provide an overview of R. tomentosa studies until 2019. This article also intends to review advances in the botanical, phytochemical, pharmacological studies and industrial applications of R. tomentosa, which will provide a useful bibliography for further investigations and applications of R. tomentosa in medicines and foods.

[The role of activator protein-1 in unstable coronary atherosclerotic changes].

OBJECTIVE: To investigate the relation between activator protein-1 (AP-1) and coronary atherosclerotic changes and the potential role of AP-1 in the stabilization of atherosclerotic plaques in patients with coronary heart disease (CHD). METHOD: 142 patients were included in this study and divided into CHD group (107) and control group (35) according to coronary angiography (CAG). The CHD group was further divided into a stable angina pectoris (SAP) group (32) and an acute coronary syndrome (ACS) group (75) according to the clinical manifestations. In addition, the CHD group was divided into A type group, B type group and C type group according to the standard of ACC/AHA coronary change in 1988. Meanwhile, the CHD group was further divided into light stenosis group, moderate stenosis group and severe stenosis group according to the degree of coronary lesion. The lysate of cells was obtained through lysis of the leucocytes from peripheral blood with cell lysis buffer. The amount of Phospho-c-Jun in lysate was measured with enzyme-linked immunosorbent assay (ELISA). The results were demonstrated with absorbance, which reflects the amount of AP-1. RESULTS: The main coronary changes in the SAP group were A type (68.7%) and the changes were mainly of light degree (53.1%); the main coronary changes in the ACS group were B type (52.0%) or C type (37.3%) and the changes were mainly of heavy degree (66.7%). The absorbance of Phospho-c-Jun in CHD group was significantly higher than that in the control subjects (1.43 +/- 0.33 vs 0.71 +/- 0.13, P < 0.001). The absorbance of Phospho-c-Jun in the ACS group was significantly higher than that in the SAP group (1.56 +/- 0.28 vs 1.14 +/- 0.25, P < 0.001). The absorbance of Phospho-c-Jun increased gradually from A type group to C type group (1.18 +/- 0.27 vs 1.42 +/- 0.26 vs 1.71 +/- 0.27, P < 0.001) and from light stenosis group to severe stenosis group (1.09 +/- 0.20 vs 1.37 +/- 0. 26 vs 1.60 +/- 0.29, P < 0.001). CONCLUSION: There is a significant relationship between AP-1 and coronary atherosclerotic changes. AP-1 may be a factor that can predict coronary arteriosclerotic progression and stability of the plaque.

[Association between plasma macrophage migration inhibitory factor concentration and coronary artery lesion severity.].

OBJECTIVE: To investigate the relationship between the plasma macrophage migration inhibitory factor (MIF), activator protein-1 (AP-1) and MMP-9 concentrations and the severity of coronary artery lesions in coronary heart disease (CHD) patients. METHODS: Patients were divided into normal controls (n = 35), stable angina pectoris (SAP, n = 32) and acute coronary syndrome (ACS, n = 75) according to the coronary angiography (CAG), clinical and laboratory examinations. The CAG severity and extent of coronary lesions were analyzed by means of Gensini coronary score system. Enzyme linked immunosorent assay was used to measure the plasma MIF, AP-1 and MMP-9 concentrations. RESULTS: Plasma MIF, AP-1 and MMP-9 concentrations were significant increased in CHD patients [MIF: (14.97 +/- 2.11) microg/L, AP-1: 1.43 +/- 0.33, MMP-9: (1.48 +/- 0.14) microg/L] compared to those in control group [MIF: (9.07 +/- 1.28) microg/L, AP-1: 0.71 +/- 0.13, MMP-9: (1.01 +/- 0.07) microg/L, all P < 0.05]. The MIF, AP-1 and MMP-9 concentrations in ACS group [MIF: (16.66 +/- 2.56) microg/L, AP-1: 1.56 +/- 0.22, MMP-9: (1.58 +/- 0.14) microg/L] were also significant higher than those in SAP group [MIF: (11.01 +/- 2.12) microg/L, AP-1: 1.04 +/- 0.25, MMP-9: (1.25 +/- 0.07) microg/L, all P < 0.05] and there was significant positive correlation between MIF, AP-1 and MMP-9 concentrations and the Gensini score of coronary artery lesions (all P < 0.05). AP-1 was positively correlated with MMP-9 in CHD patients (P < 0.05). CONCLUSIONS: Plasma MIF, AP-1 and MMP-9 concentrations were positively correlated to the severity of coronary lesions in CHD patients. Higher MIF, AP-1 and MMP-9 concentrations in ACS patients than in SAP patients might suggest higher plaque instability in ACS patients.

[Association between murine double minute 2 expression and AngII and ceramide induced endothelial cells apoptosis].

OBJECTIVE: To observe the relationship between murine double minute 2 (mdm2) expression and AngII and ceramide induced human umbilical endothelial cells apoptosis. METHOD: Human umbilical endothelial cells (ECs) were cultured in vitro and treated with angiotensin II alone or in combination with losartan (an inhibitor of AT1), PD123319 (an inhibitor of AT2) and FB1 (an inhibitor of ceramidase) respectively. ECs were also treated with different doses of C2-ceramide. The apoptosis of ECs was detected with Tunel, the mdm2 mRNA and protein expressions were measured with reverse transcription-polymerase chain reaction (RT-PCR) and Western blot. RESULTS: PD123319 and FB1 but not losartan inhibited AngII induced ECs apoptosis and down-regulated the AngII induced increased mdm2 expressions. C2-ceramide also induces ECs apoptosis and down-regulated mdm2 expressions at protein and mRNA levels in a dose-dependent manner. CONCLUSIONS: AngII binding with AT2 induces ECs apoptosis via ceramide. AngII and ceramide induce EC apoptosis by inhibiting mdm2.

Angiotensin II induces NF-kappa B activation in HUVEC via the p38MAPK pathway.

Angiotensin II (Ang II) is the main active peptide of the renin-angiotensin system (RAS), producing a number of inflammatory mediators that lead to endothelial dysfunction and the progression of atherosclerosis. Ang II-induced NF-kappaB nuclear translocation plays a pivotal role in this response. This study examines the NF-kappaB activation mechanism elicited by Ang II in human umbilical vein endothelial cells (HUVEC). Electrophoretic mobility shift assays and Western blotting revealed that Ang II, signaling via AT(1), produces a time-dependent increase in NF-kappaB DNA binding and IkappaBalpha degradation. These results also demonstrate that Ang II leads to MAPK phosphorylation and p38MAPK pathway-induced NF-kappaB activation. Furthermore, AT(1) is required for p38MAPK phosphorylation induced by Ang II. This study provides evidence that Ang II elicits NF-kappaB activation via the p38MAPK pathway in HUVEC.

Effect of sodium on blood pressure, cardiac hypertrophy, and angiotensin receptor expression in rats.

BACKGROUND: Sodium-induced hypertensive cardiac hypertrophy is related to pressure and volume overload. METHODS: Wistar rats were exposed to low and high sodium diet for 8 weeks. Angiotensin II receptor mRNA, abundance of p38 mitogen-activated protein kinase (p38MAPK), vasoconstriction of aortic rings, and angiotensin II-induced calcium increase were investigated. RESULTS: Rats on high sodium diet showed significantly elevated blood pressure. Heart weight, AT1 receptor mRNA in cardiac and aortic tissues, and abundance of p38MAPK were significantly increased in rats on high sodium diet. CONCLUSIONS: Increased AT1 receptor expression and angiotensin II-induced calcium increase are compensatory effects in sodium-induced hypertension.

Differentially expressed genes in hypertensive rats developing cerebral ischemia.

The molecular events occurring after cerebral ischemia in hypertension may include de novo expression of numerous genes. Receptor genes are predominantly involved in the process of cell death, neuroprotection and reconstruction after ischemic injury. Ischemic stroke was observed in the non-genetic, non-surgical model of hypertension, the cold-induced hypertensive rat. In hypertensive rats suppression subtractive hybridization analysis was used to identify differentially expressed receptor genes in stroke-tissue compared to normal rat brain. We found 76 genes predominantly expressed in hypertensive rat stroke-tissue. These predominantly expressed genes included genes involved in energy metabolism, signal transduction/cell regulation, and replication/transcription/translation. For example, the T3 receptor alpha was predominantly expressed in stroke-tissue, indicating that regeneration of nerves in stroke tissue may be facilitated by increased T3 receptor alpha expression.

[Changes of mitochondrial genes expressed in the brain tissue of rat in stroke-like episodes rats].

OBJECTIVE: Stroke is a complex disorder caused by a combination of genetic and environmental factors. Epidemiological studies have provided evidence of genetic influence on the development of human stroke. However, genetic changes which contribute to the development of stroke are not well known. This study was designed to gain a deep insight into that aspect. METHODS: Using cold-stimuli plus high-salt intake as environmental risk factors, the authors established a hypertension model in rats, which produced a complication of stroke. Then, they used the suppression subtractive hybridization(SSH) technique to identify the differential genes that specifically expressed in total cerebrum tissue of the rats in stroke group. A comparison was made between two populations, namely the control group and stroke group. RESULTS: By the use of SSH approach, a total of 576 clones were generated in this study from two subtractive libraries, among them 456 clones were usable and were analyzed. Genes for metabolism transcripts in stroke group were shown to be up-regulated (P<0.01). Mitochondrial transcripts were observed in a high rate of 26.5%. CONCLUSION: The findings suggested that mitochondrial genes should induce an increased sensitivity to stroke through the changes of gene expressions. Mitochondrial genes probably play important roles in the causes and effects of stroke.