Calcium-activated chloride channels (CaCCs) have been implicated in hypertension; however, the mechanism underlying their involvement is unknown. The aim of this study was to determine whether the ...CaCC ANO1 is involved in the pathogenesis of spontaneous hypertension. Arterial ANO1 expression and the effects on blood pressure (BP) of inhibiting ANO1 with an ANO1 inhibitor, T16Ainh-A01, and in vivo RNAi, were examined in spontaneously hypertensive rats (SHRs). Knockdown of ANO1 by siRNA prevented hypertensive development, and attenuation of ANO1 channel activity reduced BP in SHRs. Angiotensin II upregulated ANO1 expression in primary cultures of vascular smooth muscle cells (VSMCs). The protein level and activity of cellular ANO1 positively correlated with VSMC proliferation. Our data indicate an important role of increased ANO1 expression and activity in inducing hypertension in SHRs. It may mediate angiotensin II-dependent vascular remodeling. Our results increase the mechanistic understanding of hypertension and suggest ANO1 as a possible therapeutic target for hypertension.
•The calcium-activated chloride channel ANO1 has been implicated in hypertension.•Knockdown of ANO1 prevents hypertension in spontaneously hypertensive rats.•Angiotensin II enhances ANO1 expression via the AT1R-PI3K-Akt pathway.•ANO1 is a potential therapeutic target for spontaneous hypertension.
Rhoptry proteins (ROPs), secreted by specific rhoptry organelles of apicomplexan parasites, are determinants of parasite pathogenesis and sources of vaccine candidates. Twenty-eight ROPs of
Eimeria ...tenella
have been predicted by genomic approaches, and in the present study,
E. tenella
rhoptry protein 30 (EtROP30) was characterized. Subcellular localizations of EtROP30 in sporozoites and merozoites were in the apical complex and rhoptry-like bulb, suggesting that EtROP30 is a member of ROPs in
E. tenella
. Sequence analysis showed that EtROP30 contained an N-terminal secretory signal, a protein kinase domain with eight
E. tenella
-specific rhoptry kinase 1 subfamily (ROPK-Eten1) motifs, and a C-terminal nuclear localization sequence (NLS), making EtROP30 the only ROP that contains both a secretory signal and an NLS in
E. tenella
. Subsequent experiments showed that EtROP30 was a secreted protein in the sporozoite stage, relying on NLS for migration to the host nucleus. In addition, EtROP30 showed significantly higher expression levels in the parasite merozoite stage, indicating that EtROP30 plays a critical role during parasite reinvasion and development and may be a viable option as a vaccine candidate for anti-parasitic infection. The immunization protection efficacies of EtROP30 were evaluated. Significant improvements in mean body weight gain, reduction of cecum lesion score, and number of oocysts excreted were observed, indicating that EtROP30 has good immunogenicity against
E. tenella
. In the present study, a ROP of
E. tenella
with secretory and nuclear localization characteristics has been identified, and proved to be an effective vaccine candidate against this parasite.
In this study, new carbon nanomaterial N-doped carbon dots (NCDs) were obtained via a one-step hydrothermal method using isoleucine and citric acid as carbon precursors. TEM results showed that the ...NCD diameters were not uniform but distributed in the 6–15nm range, with an average value of 10nm. The maximum emission wavelength of the obtained NCDs was 415nm with an excitation wavelength of 370nm. Under optimal conditions, the nanoparticle can be used as sensors and exhibited a ‘turn-off’ fluorescence response to Fe3+, with a good linear relationship of (F/F0) versus Fe3+ over the concentration range of 0–20μmol/L.
•A new N-doped carbon quantum dots (NCDs) was synthesized via one-step hydrothermal method using isoleucine and citric acid as carbon precursor.•NCDs exhibit highly sensitive fluorescence ‘turn-off’ response toward Fe3+ in aqueous solution.•The mechanism of the quenching process has been discussed.
A novel red-emitting fluorescent probe (DDNA) for cysteine has been rationally designed and synthesized, which exhibited a low limit of detection to Cys (0.26 μM) as well as a favorable large stokes ...shift (λEm-λEx = 128 nm). This novel fluorophore (HDM), which features a large π-conjugation system and typical intramolecular charge transfer (ICT) process, has a long emission wavelength at 631 nm. Besides that, as a turn-on fluorescent probe, it shows high selectivity and sensitivity for Cys over other metal ions and amino acids including the similar structured homocysteine (Hcy) and glutathione (GSH). Finally, the probe DDNA was successfully applied to bioimage intracellular Cys in Hela cells with low cytotoxicity.
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•A novel fluorescence probe for cysteine with high selectivity was developed.•The probe showed a low limit of detection to Cys (0.26 μM) and a large stokes shift.•The probe is suitable for Cys detection in living cells with low cytotoxicity.
This study provides a 16.2-kyr record of mercury (Hg) deposition derived from a lacustrine sedimentary sequence in Dahu Swamp, eastern Nanling Mountains. Results indicate that changes in climatic ...conditions had a significant effect on Hg concentrations (Hg–C) and accumulation rates (Hg-AR). Multi-proxy records including dry density, grain size, geochemical elements, organic matter and pollen indicators were compared with Hg accumulation. The results revealed that the contributions of detrital input and atmospheric deposition were minor, and Hg accumulation in the sediments was closely related to changes in climatic conditions: relatively drier and colder climate would result in shrinkage of the lake water body thus favoring increased formation of organic-rich peat or gyttja and leading to enhanced absorption of Hg by organic matter and result in increases of Hg–C and Hg-AR in sediments, and vice versa. Our results indicate that variations of Hg accumulation in Dahu Swamp were greatly impacted by climate under the influences of solar insolation changes and shrinkage or expansion of ice sheets in high latitudes to the north. The results of this study provide an insight into the response of Hg accumulation to low latitude climate processes in the East Asian summer monsoon region.
Background
Whether 7,8-dihydroxyflavone (7,8-DHF), a tyrosine kinase receptor B (TrkB) agonist, modulates colonic smooth muscle motility and/or alleviates constipation has not yet been studied.
Aims
...Here, we aimed to determine how 7,8-DHF influences carbachol (CCh)-stimulated contraction of colonic strips and the in vivo effect of 7,8-DHF on constipation.
Methods
Muscle strips were isolated from rat colons for recording contractile tension and performing western blotting. Constipation was induced in rats with loperamide.
Results
Although it specifically activated TrkB, 7,8-DHF applied alone neither activated PLCγ1 in the colonic strips nor induced colonic strip contraction. However, 7,8-DHF enhanced CCh-stimulated PLCγ1 activation and strip contraction. The PLCγ1 antagonist U73122 suppressed both CCh-stimulated and 7,8-DHF-enhanced/CCh-stimulated contraction. While clarifying the underlying mechanism, we revealed that 7,8-DHF augmented muscarinic M3 receptor expression in the colonic strips. The M3-selective antagonist tarafenacin specifically inhibited the 7,8-DHF-enhanced/CCh-stimulated contraction of the colonic strips. Since 7,8-DHF increased Akt phosphorylation, and LY294002 (an antagonist of PI3K upstream of Akt) dramatically inhibited both 7,8-DHF-augmented M3 expression and 7,8-DHF-enhanced/CCh-stimulated contractions, we assumed that 7,8-DHF/TrkB/Akt was associated with the modulation of M3 expression in the colonic strips. ANA-12, a specific TrkB antagonist, not only inhibited TrkB activation by 7,8-DHF but also suppressed 7,8-DHF-enhanced cholinergic contraction, 7,8-DHF/CCh-mediated activation of PLCγ1/Akt, and M3 overexpression in colonic strips. In vivo 7,8-DHF, also by promoting intestinal motility and M3 expression, significantly alleviated loperamide-induced functional constipation in rats.
Conclusions
Our results suggest that 7,8-DHF regulates colonic motility possibly via a TrkB/Akt/M3 pathway and may be applicable for alleviating constipation.
Difficulties of in vitro culture and genetic manipulation of
Eimeria tenella
have hindered the screening of virulence factors in this parasite. In this study, the
E. tenella
rhoptry protein 30 ...(EtROP30) was expressed in
Toxoplasma gondii
(RH∆Ku80-EtROP30), and its effect on the proliferation and virulence of parasites was investigated. The results revealed that the expression of EtROP30 had no impact on the invasion and egress processes. However, the RH∆Ku80-EtROP30 strain formed larger plaques compared to the RH∆Ku80, indicating that the EtROP30 expression promotes
T. gondii
proliferation. Furthermore, the RH∆Ku80-EtROP30 strain exhibited greater pathogenicity, resulting in earlier mortality and shorter overall survival time compared to RH∆Ku80. These results imply that EtROP30 expression facilitates parasite intracellular proliferation and virulence in mice, suggesting that EtROP30 might be a candidate virulence factor of
E. tenella.
•7,8-DHF as a selective TrkB agonist is neuroprotective.•7,8-DHF has been proved to have antioxidant activity.•7,8-DHF could protect PC12 cells against 6-OHDA-induced toxicity.•The protection by ...7,8-DHF is due to eliminating ROS and improving SOD activity.
Oxidative stress-induced neuronal death plays a pivotal role in pathogenesis of neurodegenerative disorders. Recently, 7,8-dihydroxyflavone (7,8-DHF) has been shown to exert neuroprotective effects by acting as a selective tyrosine kinase receptor B (TrkB) agonist. In addition, the antioxidant action of 7,8-DHF may protect neuronal cells against oxidative injury. In the present study, we used PC12 cells, a cell line generally thought to lack TrkB, to investigate the effect of 7,8-DHF on 6-hydroxydopamine (6-OHDA)-induced cytotoxicity and the underlying mechanism. We found that 7,8-DHF effectively prevented cell death, apoptosis and mitochondrial dysfunction induced by 6-OHDA. In a cell free system, 7,8-DHF did not slow down extracellular auto-oxidation of 6-OHDA which may generate H2O2. However, We found that 7,8-DHF dramatically reduced cellular malondialdehyde content and phospho-histone H2A.X protein level. 7,8-DHF also elevated total superoxide dismutase activity in 6-OHDA-treated cells. These results indicate that 7,8-DHF might protect PC12 cells against 6-OHDA-induced cytotoxicity through its powerful antioxidant activity. By acting as a potent TrkB agonist and an antioxidant together with its easiness to pass across blood–brain barrier, 7,8-DHF may be developed into a promising candidate in treatment of neurodegenerative diseases.
Plasma LDL is produced from catabolism of VLDL and cleared from circulation mainly via the hepatic LDL receptor (LDLR). Proprotein convertase subtilisin/kexin type 9 (PCSK9) promotes LDLR ...degradation, increasing plasma LDL-C levels. Circulating PCSK9 is mainly secreted by the liver, whereas VLDL is exclusively secreted by hepatocytes. However, the mechanism regulating their secretion is not completely understood. Surfeit 4 (Surf4) is a cargo receptor localized in the ER membrane. It recruits cargos into coat protein complex II vesicles to facilitate their secretion. Here, we investigated the role of Surf4 in VLDL and PCSK9 secretion. We generated Surf4 liver-specific knockout mice and found that knockout of Surf4 did not affect PCSK9 secretion, whereas it significantly reduced plasma levels of cholesterol, triglyceride, and lipid-binding protein apolipoprotein B (apoB). In cultured human hepatocytes, Surf4 coimmunoprecipitated and colocalized with apolipoprotein B100, and Surf4 silencing reduced secretion of apolipoprotein B100. Furthermore, knockdown of Surf4 in LDLR knockout (Ldlr−/−) mice significantly reduced triglyceride secretion, plasma levels of apoB and non-HDL-C, and the development of atherosclerosis. However, Surf4 liver-specific knockout mice and Surf4 knockdown in Ldlr−/− mice displayed similar levels of liver lipids and plasma alanine aminotransferase activity as control mice, indicating that inhibition of Surf4 does not cause notable liver damage. Expression of stearoyl-CoA desaturase-1 was also reduced in the liver of these mice, suggesting a reduction in de novo lipogenesis. In summary, hepatic deficiency of Surf4 reduced VLDL secretion and the development of atherosclerosis but did not cause significant hepatic lipid accumulation or liver damage.
Optimization of forging process to improve the microstructure and mechanical properties of 2195 Al–Cu–Li alloy forgings is an urgent issue. In this study, a homogenized 2195 alloy ingot was subjected ...to multi-directional forging (MDF), annealing, and forging at 500 °C, 420 °C, and 240 °C with a 50% reduction in cross-sectional area, followed by a T8 heat treatment (involving solution, quenching, cold compression, and aging). The microstructural evolution during the process and the final mechanical properties in three orthogonal directions were examined. The results showed that the grain structures of the alloy were significantly refined after MDF by dynamic recrystallization (DRX), but the structure was thermally unstable and formed coarse grains during subsequent annealing by static recrystallization (SRX). The T8-treated samples forged at 500 °C, 420 °C, and 240 °C obtained fine and uniform grain structures by DRX, inhomogeneous grain structures by partial SRX, and uniform, equiaxed grain structures by full SRX, respectively. The average grain size of the forging increased with decreasing forging temperature because more significant SRX occurred for the forging that was deformed at lower temperatures. The grain structures had minimal influence on precipitation behavior and strength but had a significant influence on elongation. The fine and uniform grain structures improved the elongation; whereas, the inhomogeneous grain structures, which contained extremely large grains, significantly deteriorated the elongation. The uniform, equiaxed grain structures decreased the anisotropy in three orthogonal directions and maintained fine elongation even though the average grain size of the forging was the largest.
Graphic Abstract
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