[Screening for asymptomatic atrial fibrillation in elder community populations in Dalian: a single center study]

Objective: We aimed to determine the epidemiological characteristics of asymptomatic AF in elder community population (≥65 years old) to analyze the detection rate of different screening methods. Methods: The study was a prospective cohort study. The elder (≥65 years old) residents who voluntarily participated in free physical examination in Dalian community were selected. The participants were randomly divided into screening group (including intensive screening group and single screening group) and control group. The control group received interrogation, medical history collection and routine 12-lead electrocardiogram (ECG) examination. Screening group received an additional single-lead ambulatory ECG equipment worn for 5-7 days. Intensive screening group received two equal-length wearings in 2020 and 2021 respectively, while one screening group only wore once in 2020. Results: Finally 3 340 residents ((70.7±5.0) years old) which consisted of 1 488 males (44.55%) were enrolled. There were 1 945 residents in screening group, including 859 in intensive screening group and 1 086 in one-time screening group. The control group included 1 395 people. Detection rate of asymptomatic AF was significantly higher in screening group than control group (79(4.06%) vs. 24(1.72%), P<0.001). Higher detection rate was found in screening group than control group in AF risk factors (1 or 2-3) subgroups and CHA2DS2-VASc score (2-3 or≥4) subgroups (P<0.05). Additionally, no difference was found between intensive screening group and single screening group (42(4.89%) vs. 37(3.41%), P=0.100). Intensive screening increased detection rate (7(6.93%) vs. 1(0.58%), P=0.009) only in residents those with low thrombosis risk (CHA2DS2-VaSc<2). Conclusions: Screening in elderly (≥65 years old) can significantly improve the detection rate of asymptomatic AF by wearing single lead dynamic ECG device. The rate increased significantly with the increase of risk factors associated with AF by single screening. In addition, repeat screening of the same method may only improve detection rates in the group with low risk thrombotic scores and non-combination of AF risk factors.Screening methods that are appropriate for different populations may require further exploration.

ANP32B suppresses B-cell acute lymphoblastic leukemia through activation of PU.1 in mice

ANP32B, a member of the acidic leucine-rich nuclear phosphoprotein 32 kDa (ANP32) family of proteins, is critical for normal development because its constitutive knockout mice are perinatal lethal. It is also shown that ANP32B acts as a tumor-promoting gene in some kinds of cancer such as breast cancer and chronic myelogenous leukemia. Herein, we observe that ANP32B is lowly expressed in B-cell acute lymphoblastic leukemia (B-ALL) patients, which correlates with poor prognosis. Furthermore, we utilized the N-myc or BCR-ABL^p190 -induced B-ALL mouse model to investigate the role of ANP32B in B-ALL development. Intriguingly, conditional deletion of Anp32b in hematopoietic cells significantly promotes leukemogenesis in two B-ALL mouse models. Mechanistically, ANP32B interacts with purine rich box-1 (PU.1) and enhances the transcriptional activity of PU.1 in B-ALL cells. Overexpression of PU.1 dramatically suppresses B-ALL progression, and highly expressed PU.1 significantly reverses the accelerated leukemogenesis in Anp32b-deficient mice. Collectively, our findings identify ANP32B as a suppressor gene and provide novel insight into B-ALL pathogenesis.

FBXO22 promotes leukemogenesis by targeting BACH1 in MLL-rearranged acute myeloid leukemia

BACKGROUND

Selectively targeting leukemia stem cells (LSCs) is a promising approach in treating acute myeloid leukemia (AML), for which identification of such therapeutic targets is critical. Increasing lines of evidence indicate that FBXO22 plays a critical role in solid tumor development and therapy response. However, its potential roles in leukemogenesis remain largely unknown.

METHODS

We established a mixed lineage leukemia (MLL)-AF9-induced AML model with hematopoietic cell-specific FBXO22 knockout mice to elucidate the role of FBXO22 in AML progression and LSCs regulation, including self-renewal, cell cycle, apoptosis and survival analysis. Immunoprecipitation combined with liquid chromatography-tandem mass spectrometry analysis, Western blotting and rescue experiments were performed to study the mechanisms underlying the oncogenic role of FBXO22.

RESULTS

FBXO22 was highly expressed in AML, especially in MLL-rearranged (MLLr) AML. Upon FBXO22 knockdown, human MLLr leukemia cells presented markedly increased apoptosis. Although conditional deletion of Fbxo22 in hematopoietic cells did not significantly affect the function of hematopoietic stem cells, MLL-AF9-induced leukemogenesis was dramatically abrogated upon Fbxo22 deletion, together with remarkably reduced LSCs after serial transplantations. Mechanistically, FBXO22 promoted degradation of BACH1 in MLLr AML cells, and overexpression of BACH1 suppressed MLLr AML progression. In line with this, heterozygous deletion of BACH1 significantly reversed delayed leukemogenesis in Fbxo22-deficient mice.

CONCLUSIONS

FBXO22 promotes MLLr AML progression by targeting BACH1 and targeting FBXO22 might be an ideal strategy to eradicate LSCs without influencing normal hematopoiesis.

[Expression of METTL14 in epithelial ovarian cancer and the effect on cell proliferation, invasion and migration of A2780 and SKOV3 cells]

Objective: To study the expression of methyltransferase-like protein 14 (METTL14) in epithelial ovarian cancer and its clinical significance, and to explore the effect of METTL14 expression on the proliferation, invasion and migration of ovarian cancer cells. Methods: Immunohistochemistry (IHC) was used to detect METTL14 expression in tumor tissue samples, and analyze the relationships among METTL14 expression, clinicopathological factors, and prognosis in ovarian cancer. Lentiviral vectors and small interfering RNA (siRNA) were used to up-regulate and down-regulate the METTL14 expression in ovarian cancer cell lines A2780 and SKOV3, respectively. Liquid chromatography-tandem mass spectrometry (LC-MS/MS) method was used to detect the N6-methyladenosine (m6A) content in ovarian cancer cells. Cell counting kit-8 (CCK-8), wound healing assay, and transwell assay were used to examine the function of METTL14 expression in the cells. Results: (1) The IHC score of METTL14 protein was 6.2±3.7 in 20 samples of ovarian cancer tissues and 3.3±2.5 in 15 samples of normal ovarian tissues, and the difference was statistically significant (t=-2.64, P=0.012). Among the patients who suffered from ovarian cancer, there were 69 cases with high expression of METTL14 protein (IHC score≥6), accounting for 57.0% (69/121), and the cases with low expression of METTL14 protein (IHC score<6) accounting for 43.0% (52/121). Compared with the patients with low expression of METTL14, the patients with high expression of METTL14 had later stages, higher rates of lymph node metastasis, abdominal metastasis, and more ascite amount. The differences were statistically significant (all P<0.05). The overall survival rate was significantly lower in patients with high METTL14 expression than the low expression (P=0.009). (2) LC-MS/MS data showed that the relative expression of m6A in A2780 and SKOV3 cells in the lentivirus (LV)-METTL14 group were 0.213±0.024 and 0.181±0.018, which were significantly higher than those in the LV-normal control (NC) group (0.109±0.022 and 0.128±0.020; all P<0.05). While the relative expression of m6A in A2780 and SKOV3 cells in the si-METTL14 group were 0.063±0.012 and 0.069±0.015, which were significantly lower than the expression in si-NC group of 0.108±0.014 and 0.121±0.014 (all P<0.05). CCK-8 assay showed that the absorbance values were significantly lower in the si-METTL14 group compared with the si-NC group at 36, 48, 60 hours (all P<0.05); while were significantly increased in the LV-METTL14 group compared with the LV-NC group at 48, 60 hours (all P<0.01). Scratch wound assays showed that the migration rate of the si-METTL14 group was lower than those of the si-NC group, while the LV-METTL14 group were higher than the LV-NC group by 24 hours, the differences were statistically significant (all P<0.01). Cell migration and invasion were detected by transwell migration and invasion assays. After cultivated for 24 hours, the invasion cell number and the migration cell number in the si-METTL14 group were less than those in the si-NC group. While the invasion cell number and the migration cell number in the LV-METTL14 group were more than those in the LV-NC group, respectively. The differences were statistically significant (all P<0.01). Conclusion: Patients with high METTL14 expression have a worse prognosis in ovarian cancer, which may increase the m6A modification of ovarian cancer cells and promote cells proliferation, invasion and migration.

[Feasibility of radiofrequency ablation for cancer patients with atrial fibrillation]

Objective: To analyze the impact of cancer on the recurrence rate of atrial fibrillation (AF) after AF radiofrequency ablation and further evaluate the feasibility of radiofrequency ablation therapy in cancer patients with AF. Methods: This study was a single-center, retrospective study. Cancer patients with AF undergoing radiofrequency ablation for the first time in the First Affiliated Hospital of Dalian Medical University from May 30, 2008 to September 30, 2018 were included (cancer group). AF patients without cancer undergoing radiofrequency ablation for the first time during the same period served as non-cancer group. Clinical data including age, gender, past history, cancer and AF-related parameters, etc. were analyzed. Patients were followed up after radiofrequency ablation. The primary endpoints were AF recurrence or all-cause death. Kaplan-Meier survival analysis was used to analyze the effect of cancers on the recurrence after AF ablation. The multivariate cox regression analysis was further applied to correct for other confounding factors to analyze whether the impact of cancers on the recurrence of atrial fibrillation was statistically significant. Results: A total of 90 patients were enrolled, there were 30 patients in the cancer group (mean age (64.8±6.6) years, 16 (53.3%) males) and 60 patients in the non-cancer group (mean age (63.6±6.2) years, 32 (53.3%) males). Clinical data, such as age, gender, and cancer treatment, were similar between the two groups. During an average follow-up period of (328.7±110.2) days, there were 6 AF recurrences (recurrence rate 20.0%) in the cancer group, and 17 AF recurrences (recurrence rate 28.3%) in the control group. AF recurrence rate was similar between the two groups (P>0.05). During the follow-up period, there was no all-cause death in the two groups. Kaplan-Meier survival analysis showed that cancer was not related to AF recurrence after radiofrequency ablation (P = 0.383). After adjusting for other confounding factors, the multivariate Cox regression analysis showed that cancer was not an independent predictor of AF recurrence after radiofrequency ablation (HR=0.508, 95%CI: 0.192-1.342, P = 0.172). Conclusions: The combination of cancer has no impact on the recurrence of AF after radiofrequency ablation. For cancer patients with AF, radiofrequency ablation therapy can be considered as a feasible heart rhythm control treatment strategy.

[Association of RTN4 gene rs2864052 and rs6545468 with the susceptibility of nasopharyngeal carcinoma in Guangxi Zhuang population]

Objective:To study the relationship of the polymorphism of RTN4 gene rs2864052 and rs6545468 and haplotype with the susceptibility of nasopharyngeal carcinoma in Guangxi Zhuang population. Method:The polymorphism of Nogo gene (rs2864052,rs6545468) and haplotype were analyzed using the method of single-base extension PCR and DNA sequencing in 282 cases of nasopharyngeal carcinoma (NPC) and 199 healthy persons (control group) in Guangxi Zhuang Autonomous Region. Result:There were no differences between the NPC's patients and controls in the genotype and allele frequencies of RTN4 gene rs2864052 site,or rs6545468 site. The frequency of AG haplotype in the NPC's patients was significantly lower than in the controls(P=0.004, OR=0.14,95%CI=0.31-0.68). Conclusion:The haplotype AG of RTN4 gene rs2864052 and rs6545468 sites may reduce the risk of nasopharyngeal carcinoma in Guangxi Zhuang population.

Ischemia-reperfusion injury in an aortic dissection patient

Aortic dissection is a life-threatening emergency. Well-established risk factors include systemic hypertension, hereditary connective tissue diseases (Marfan syndrome and Ehlers-Danlos syndrome), coarctation of the aorta, bicuspid aortic valve, aortitis, and arch hypoplasia. Ischemia of the viscera, the kidneys, the spinal cord, or the lower extremities due to malperfusion constitutes life-threatening complications that have to be considered in the treatment strategy.We report a rare case of symptomatic ischemia of the lower extremities due to aortic dissection. This case demonstrates that the treating physician needs to be vigilant for ischemia reperfusion injuries such as osteofascial compartment syndrome and acute renal failure in aortic dissection.

Elevating bioavailability of curcumin via encapsulation with a novel formulation of artificial oil bodies

Utilization of curcumin has been limited due to its poor oral bioavailability. Oral bioavailability of hydrophobic compounds might be elevated via encapsulation in artificial seed oil bodies. This study aimed to improve oral bioavailability of curcumin via this encapsulation. Unfortunately, curcumin was indissoluble in various seed oils. A mixed dissolvent formula was used to dissolve curcumin, and the admixture was successfully encapsulated in artificial oil bodies stabilized by recombinant sesame caleosin. The artificial oil bodies of relatively small sizes (150 nm) were stably solidified in the forms of powder and tablet. Oral bioavailability of curcumin with or without encapsulation in artificial oil bodies was assessed in Sprague-Dawley male rats. The results showed that encapsulation of curcumin significantly elevated its bioavailability and provided the highest maximum whole blood concentration (Cmax), 37 ± 28 ng/mL, in the experimental animals 45 ± 17 min (t(max)) after oral administration. Relative bioavailability calculated on the basis of the area under the plasma concentration-time curve (AUC) was increased by 47.7 times when curcumin was encapsulated in the artificial oil bodies. This novel formulation of artificial oil bodies seems to possess great potential to encapsulate hydrophobic drugs for oral administration.

Decoupling free-carriers contributions from oxygen-vacancy and cation-substitution in extrinsic conducting oxides

The intrinsic oxygen-vacancies and the extrinsic dopants are two major fundamental free-carrier sources for the extrinsic conducting oxides, such as Sn-doped In(2)O(3). Yet, the individual contributions of the above two free-carrier sources to the total carrier concentrations have never been unraveled. A carrier-concentration separation model is derived in this work, which can define the individual contributions to the total carrier concentration from the intrinsic oxygen-vacancies and the extrinsic dopants, separately. The individual contributions obtained from the present carrier-concentration separation model are verified by the two-state trapping model, photoluminescence, and positron annihilation lifetime (PAL) spectroscopy. In addition, the oxygen-vacancy formation energy of the Sn:In(2)O(3) thin film is determined to be 0.25 eV by PAL spectroscopy.

Repression of P66Shc expression by SIRT1 contributes to the prevention of hyperglycemia-induced endothelial dysfunction

RATIONALE

Inactivation of the p66Shc adaptor protein confers resistance to oxidative stress and protects mice from aging-associated vascular diseases. However, there is limited information about the negative regulating mechanisms of p66Shc expression in the vascular system.

OBJECTIVE

In this study, we investigated the role of SIRT1, a class III histone deacetylase, in the regulation of p66Shc expression and hyperglycemia-induced endothelial dysfunction.

METHODS AND RESULTS

Expressions of p66Shc gene transcript and protein were significantly increased by different kinds of class III histone deacetylase (sirtuin) inhibitors in human umbilical vein endothelial cells and 293A cells. Adenoviral overexpression of SIRT1 inhibited high-glucose-induced p66Shc upregulation in human umbilical vein endothelial cells. Knockdown of SIRT1 increased p66Shc expression and also increased the expression levels of plasminogen activator inhibitor-1 expression, but decreased manganese superoxide dismutase expression in high-glucose conditions. However, knockdown of p66Shc significantly reversed the effects of SIRT1 knockdown. In addition, p66Shc overexpression significantly decreased manganese superoxide dismutase expression and increased plasminogen activator inhibitor-1 expression in high-glucose conditions, which were recovered by SIRT1 overexpression. Moreover, compared to streptozotocin-induced wild-type diabetic mice, endothelium-specific SIRT1 transgenic diabetic mice had decreased p66Shc expression at both the mRNA and the protein levels, improved endothelial function, and reduced accumulation of nitrotyrosine and 8-OHdG (markers of oxidative stress). We further found that SIRT1 was able to bind to the p66Shc promoter (-508 bp to -250 bp), resulting in a decrease in the acetylation of histone H3 bound to the p66Shc promoter region.

CONCLUSION

Our findings indicate that repression of p66Shc expression by SIRT1 contributes to the protection of hyperglycemia-induced endothelial dysfunction.

SIRT1 acts as a modulator of neointima formation following vascular injury in mice

RATIONALE

Vascular smooth muscle cell (VSMC) proliferation and migration are crucial events involved in the pathophysiology of vascular diseases. Sirtuin 1 (SIRT1), a class III histone deacetylase (HDAC), has been reported to have the function of antiatherosclerosis, but its role in neointima formation remains unknown.

OBJECTIVE

The present study was designed to investigate the role of SIRT1 in the regulation of neointima formation and to elucidate the underlying mechanisms.

METHODS AND RESULTS

A decrease in SIRT1 expression was observed following carotid artery ligation. smooth muscle cell (SMC)-specific human SIRT1 transgenic (Tg) mice were generated. SIRT1 overexpression substantially inhibited neointima formation after carotid artery ligation or carotid artery wire injury. In the intima of injured carotid arteries, VSMC proliferation (proliferating cell nuclear antigen (PCNA)-positive cells) was significantly reduced. SIRT1 overexpression markedly inhibited VSMC proliferation and migration and induced cell cycle arrest at G1/S transition in vitro. Accordingly, SIRT1 overexpression decreased the induction of cyclin D1 and matrix metalloproteinase-9 (MMP-9) expression by treatment with serum and TNF-α, respectively, whereas RNAi knockdown of SIRT1 resulted in the opposite effect. Decreased cyclin D1 and MMP-9 expression/activity were also observed in injured carotid arteries from SMC-SIRT1 Tg mice. Furthermore, 2 targets of SIRT1, c-Fos and c-Jun, were involved in the downregulation of cyclin D1 and MMP-9 expression.

CONCLUSIONS

Our findings demonstrate the inhibitory effect of SIRT1 on the VSMC proliferation and migration that underlie neointima formation and implicate SIRT1 as a potential target for intervention in vascular diseases.

A transgenic Cre mouse line for the study of cortical and hippocampal development

Wnt signaling regulates cortical and hippocampal development. In a previous study we found that a particular Wnt receptor, Frizzled9 (Fzd9), was selectively expressed in both the developing and adult hippocampus. Taking advantage of the specificity of this promoter, we generated a transgenic cre mouse line using the putative control elements of the Fzd9 gene. In the Fzd9-cre mice, Cre is mainly detected in the developing cortex and hippocampus and is confined to the CA fields and dentate gyrus in adults. Furthermore, by crossing the Fzd9-cre mouse with the ROSA26 reporter line, we examined the activity of Cre and found that it has very high recombination efficiency. Thus, this mouse line will likely prove to be a useful tool for studying cortical and hippocampal development via activation or inactivation of interesting genes.

Involvement of the p65/RelA subunit of NF-kappaB in TNF-alpha-induced SIRT1 expression in vascular smooth muscle cells

The proinflammatory cytokine TNF-alpha plays an important role in stimulating inflammatory responses of vascular smooth muscle cells (VSMCs). The anti-inflammatory function of Sirtuin 1 (SIRT1), a NAD-dependent class III histone/protein deacetylase, has been well documented, but how SIRT1 is regulated under inflammatory conditions is largely unknown. In the present research, we showed that levels of SIRT1 mRNA and protein expression increased in TNF-alpha-treated VSMCs. Overexpression of the p65/RelA subunit of NF-kappaB, a TNF-alpha-activated inflammatory transcription factor, in A7r5 cells, upregulated SIRT1 mRNA and protein expression as well as SIRT1 promoter activity, while knockdown of endogenous p65/RelA expression by RNAi not only led to a decrease in SIRT1's basal protein expression and promoter activity, but almost abolished the TNF-alpha-induced elevation of SIRT1 protein expression and SIRT1 promoter activity. Furthermore, using promoter deletion analysis and chromatin immunoprecipitation assays, we found that p65/RelA bound to the SIRT1 promoter at a consensus NF-kappaB binding site. Our study indicates that p65/RelA mediates the TNF-alpha-induced elevated expression of SIRT1 in VSMCs, shedding new light on the regulation of SIRT1 under inflammatory conditions.

SIRT1 suppresses activator protein-1 transcriptional activity and cyclooxygenase-2 expression in macrophages

SIRT1 (Sirtuin type 1), a mammalian orthologue of yeast SIR2 (silent information regulator 2), has been shown to mediate a variety of calorie restriction (CR)-induced physiological events, such as cell fate regulation via deacetylation of the substrate proteins. However, whether SIRT1 deacetylates activator protein-1 (AP-1) to influence its transcriptional activity and target gene expression is still unknown. Here we demonstrate that SIRT1 directly interacts with the basic leucine zipper domains of c-Fos and c-Jun, the major components of AP-1, by which SIRT1 suppressed the transcriptional activity of AP-1. This process requires the deacetylase activity of SIRT1. Notably, SIRT1 reduced the expression of COX-2, a typical AP-1 target gene, and decreased prostaglandin E(2) (PGE(2)) production of peritoneal macrophages (pMPhis). pMPhis with SIRT1 overexpression displayed improved phagocytosis and tumoricidal functions, which are associated with depressed PGE(2). Furthermore, SIRT1 protein level was up-regulated in CR mouse pMPhis, whereas elevated SIRT1 decreased COX-2 expression and improved PGE(2)-related macrophage functions that were reversed following inhibition of SIRT1 deacetylase activity. Thus, our results indicate that SIRT1 may be a mediator of CR-induced macrophage regulation, and its deacetylase activity contributes to the inhibition of AP-1 transcriptional activity and COX-2 expression leading to amelioration of macrophage function.

Fate of nonylphenol polyethoxylates and their metabolites in four Beijing wastewater treatment plants

Four Beijing wastewater treatment plants (WWTPs) were selected to investigate behaviours of nonylphenol polyethoxylates and their metabolites in different wastewater treatment processes. The results showed that the total concentrations of nonylphenolic compounds in the influents of the four WWTPs ranged from 0.115 to 0.347 mumol/L, as well as their removal efficiencies ranging from 75.7% to 90.8%. Both influent concentrations and removal efficiencies of nonylphenol polyethoxylates were correlated to seasons as follows: higher in the summer than in the winter, and influent concentrations were lower during the rain weather. The analysis revealed that 21.8-47.6% of nonylphenol polyethoxylates and their metabolites entering WWTPs were released via effluents and excess sludge, leaving a great part of them for biodegradation. Nonylphenol and short-chain nonylphenol polyethoxylates were disposed to the environment mainly via sewage sludge, while carboxylated nonylphenol polyethoxylates were the most abundant group of nonylphenol polyethoxylates in effluents.

Endothelium-specific overexpression of human IC53 downregulates endothelial nitric oxide synthase activity and elevates systolic blood pressure in mice

AIMS

Hypertension is one of the major risk factors for cardiovascular diseases. Endothelial cells (ECs) exert important functions in the regulation of blood pressure. A novel gene, IC53, as an isoform of the cyclin-dependent kinase (CDK)-binding protein gene C53, is mainly expressed in vascular ECs and is upregulated in the failing heart of rats. Overexpression of IC53 promotes proliferation of ECs. To examine whether IC53 plays a role in the regulation of vascular tone and blood pressure, we constructed a transgenic (tg) mouse model of the IC53 gene and studied its phenotypes relevant to vascular function.

METHODS AND RESULTS

IC53 cDNA was cloned from a human aorta cDNA library. Using the endothelium-specific VE-cadherin promoter, we constructed tg mice in which IC53 was specifically overexpressed in vascular endothelia and found that the tg mice exhibit elevated systolic blood pressure (SBP) in contrast to the wild-type (wt) controls. Further studies revealed impaired endothelium-dependent vasodilation, reduced nitric oxide (NO) production and decreased endothelial NO synthase (eNOS) expression, and activity in the tg mice. Inhibition of IC53 in human umbilical vein ECs induces upregulation of eNOS activity.

CONCLUSION

Our results indicate that IC53 participates in the regulation of vascular homeostasis. Endothelium-specific overexpression of IC53 is associated with elevated SBP, which may be in part attributed to the downregulation of eNOS signalling.

Human paraoxonase gene cluster transgenic overexpression represses atherogenesis and promotes atherosclerotic plaque stability in ApoE-null mice

The paraoxonase (PON) gene cluster consists of the PON1, PON2, and PON3 genes, each of which can individually inhibit atherogenesis. To analyze the functions of the PON gene cluster (PC) in atherogenesis and plaque stability, human PC transgenic (Tg) mice were generated using bacterial artificial chromosome. The high-density lipoprotein from Tg mice exhibited increased paraoxonase activity. When crossed to the ApoE-null background and challenged by high-fat diet, PC Tg/ApoE-null mice formed significantly fewer atherosclerotic lesions. However overexpression of the PC transgene had no additive effect on atherosclerosis compared to the overexpression of the single PON1 or PON3 transgene. Plaques from PC Tg/ApoE-null mice exhibited increased levels of collagen and smooth muscle cells, and reduced levels of macrophages and lipid, compared with those from ApoE-null mice, indicating lesions of PC Tg/ApoE-null mice had characteristics of more stable plaques than those of ApoE-null mice. PC transgene enhanced high-density lipoprotein ability to protect low-density lipoprotein against oxidation in vitro. Serum intercellular adhesion molecule-1 and monocyte chemoattractant protein-1 were also repressed by PC transgene. Proatherogenic reactions of Tg mouse peritoneal macrophages induced by oxidized low-density lipoprotein were inhibited by PC transgene, as indicated by reduced reactive oxygen species generation, inflammation, matrix metalloproteinase-9 expression, and foam cell formation. Our results demonstrate that the PC transgene not only represses atherogenesis but also promotes atherosclerotic plaque stability in vivo. PC may therefore be a useful target for atherosclerosis treatment.

[Effects of Batroxobin on distal anastomotic intimal hyperplasia after expanded polytetrafluoroethylene bypass grafting in dog common carotid artery]

OBJECTIVE

To study the morphological behavior, the expression of MCP-1 and PDGF-B of distal anastomotic neointima after expanded polytetrafluoroethylene (ePTFE) bypass grafting. And to identify the effects of Batroxobin (BX) on distal anastomotic intimal hyperplasia.

METHODS

12 adult mongrel dogs underwent end to side bypass grafting in left common carotid artery using ePTFE vascular graft (6mm in diameter, 5cm in length) were divided randomly into two groups. All 12 bypass grafts were removed 28 days after grafting and distal anastomotic parts were obtained. Using HE, Masson, IHC, RT-PCR and western blot, we analyzed the thickness, relative content of ECM, SMC PCNA index, expression of MCP-1 and PDGF-B in distal anastomotic neointima. And we compared the differences between the two groups.

RESULTS

28 day after grafting, the neointima was formed by SMC and ECM and was covered by epithelial cells. After using BX, the thickness of neointima was reduced [( 381.3 +/- 144.7) microm versus (213.8 +/- 29.0) microm, P < 0.05] and the relative content of ECM were significantly decreased (P = 0.006). The PCNA index (P = 0.109) and PDGF-B level (P = 0.055 by RT-PCR and P = 0.337 by WB) between the two groups had no significant difference. MCP-1 level was markedly decreased (P = 0.025 by RT-PCR and P = 0.016 by WB).

CONCLUSIONS

Using BX after ePTFE grafting could effectively reduce the relative content of ECM, reduce the expression of MCP-1 and decrease the thickness of neointima in the early time.

Endothelium-specific overexpression of class III deacetylase SIRT1 decreases atherosclerosis in apolipoprotein E-deficient mice

AIMS

Hazardous environmental and genetic factors can damage endothelial cells to induce atherosclerotic vascular disease. Recent studies suggest that class III deacetylase SIRT1 may promote cell survival via novel antioxidative mechanisms. The current study tested the hypothesis that SIRT1, specifically overexpressed in the endothelium, is atheroprotective.

METHODS AND RESULTS

Human umbilical vein endothelial cells (HUVECs) were used to study the effects of oxidized low-density lipoprotein (LDL) on SIRT1 expression. Endothelial cell-specific SIRT1 transgenic (SIRT1-Tg) mice were used to study the effects of SIRT1 on aortic vascular tone. SIRT1-Tg mice were crossed with apolipoprotein E null (apoE(-/-)) mice to obtain SIRT1-Tg/apoE(-/-) mice for the analysis of atherogenesis in the presence of endothelial overexpression of SIRT1. SIRT1 expression in HUVECs was increased by the treatment with oxidative LDL. Adenoviral-mediated overexpression of SIRT1 was protective of apoptosis of HUVECs. Calorie restriction increased, whereas high-fat diet decreased, the SIRT1 expression in mouse aortas. In SIRT1-Tg mice, high fat-induced impairment in endothelium-dependent vasorelaxation was improved compared with that of wild-type littermates. This was accompanied by an upregualtion of aortic endothelial nitric oxide synthase expression in the SIRT1-Tg mice. The SIRT1-Tg/apoE(-/-) mice had less atherosclerotic lesions compared with apoE(-/-) controls, without affecting blood lipids and glucose levels.

CONCLUSION

These results suggest that endothelium-specific SIRT1 overexpression likely suppresses atherogenesis via improving endothelial cell survival and function.

The apolipoprotein CIII enhancer regulates both extensive histone modification and intergenic transcription of human apolipoprotein AI/CIII/AIV genes but not apolipoprotein AV

The apolipoprotein (apo) AI/CIII/AIV/AV cluster genes are expressed at different levels in the liver and intestine. The apoCIII enhancer, a common regulatory element, regulates the tissue-specific expression of apoAI, apoCIII, and apoAIV but not apoAV. To study this regulation at the chromatin level, the histone modifications and intergenic transcription in the human apoAI/CIII/AIV/AV cluster were investigated in HepG2 and Caco-2 cells and in the livers of transgenic mice carrying the human gene cluster constructs with or without the apoCIII enhancer. We found that both the promoters and the intergenic regions of the apoAI/CIII/AIV genes were hyperacetylated and formed an open subdomain that did not include the apoAV gene. Hepatic and intestinal intergenic transcripts were identified to transcribe bidirectionally with strand preferences along the cluster. The deletion of the apoCIII enhancer influenced both histone modification and intergenic transcription in the apoAI/CIII/AIV gene region. These results demonstrate that the apoCIII enhancer contributes to the maintenance of an active chromatin subdomain of the apoAI/CIII/AIV genes, but not apoAV.

Targeted Cardiac Overexpression of A20 Improves Left Ventricular Performance and Reduces Compensatory Hypertrophy After Myocardial Infarction

Background— A20 was originally characterized as a tumor necrosis factor–inducible gene in human umbilical vein endothelial cells. As an inhibitor of nuclear factor-κB signaling, A20 protects against apoptosis, inflammation, and cardiac hypertrophy. In the present study, we tested the hypothesis that cardiac-specific overexpression of A20 could protect the heart from myocardial infarction.

Methods and Results— We investigated the role of constitutive human A20 expression in acute myocardial infarction using a transgenic model. Transgenic mice containing the human A20 gene under the control of the α-myosin heavy chain promoter were constructed. Myocardial infarction was produced by coronary ligation in A20 transgenic mice and control animals. The extent of infarction was then quantified by 2-dimensional and M-mode echocardiography and by molecular and pathological analyses of heart samples in infarct and remote heart regions 7 days after myocardial infarction. Constitutive overexpression of A20 in the murine heart resulted in attenuated infarct size and improved cardiac function 7 days after myocardial infarction. Significantly, we found a decrease in nuclear factor-κB signaling and apoptosis, as well as proinflammatory response, cardiac remodeling, and interstitial fibrosis, in noninfarct regions in the hearts of constitutive A20-expressing animals compared with control animals.

Conclusions— Cardiac-specific overexpression of A20 improves cardiac function and inhibits cardiac remodeling, apoptosis, inflammation, and fibrosis after acute myocardial infarction.

Overexpression of myofibrillogenesis regulator-1 aggravates cardiac hypertrophy induced by angiotensin II in mice

Myofibrillogenesis regulator-1 (MR-1) augments cardiomyocytes hypertrophy induced by angiotensin II (Ang II) in vitro. However, its roles in cardiac hypertrophy in vivo remain unknown. Here, we investigate whether MR-1 can promote cardiac hypertrophy induced by Ang II in vivo and elucidate the molecular mechanisms of MR-1 on cardiac hypertrophy. We used a model of Ang II-induced cardiac hypertrophy by infusion of Ang II in female mice. In wild-type mice subjected to the Ang II infusion, cardiac hypertrophy developed after 2 weeks. In mice overexpressing human MR-1 (transgenic), however, cardiac hypertrophy was significantly greater than in wild-type mice as estimated by heart weight:body weight ratio, cardiomyocyte area, and echocardiographic measurements, as well as cardiac atrial natriuretic peptide and B-type natriuretic peptide mRNA and protein levels. Our further results showed that cardiac inflammation and fibrosis observed in wild-type Ang II mice were augmented in transgenic Ang II mice. Importantly, increased nuclear factor kappaB activation was significantly increased higher in transgenic mice compared with wild-type mice after 2 weeks of Ang II infusion. In vitro experiments also revealed that overexpression of MR-1 enhanced Ang II-induced nuclear factor kappaB activation, whereas downregulation of MR-1 blocked it in cardiac myocytes. In conclusion, our results suggest that MR-1 plays an aggravative role in the development of cardiac hypertrophy via activation of the nuclear factor kappaB signaling pathway.

A20 inhibits oxidized low-density lipoprotein-induced apoptosis through negative Fas/Fas ligand-dependent activation of caspase-8 and mitochondrial pathways in murine RAW264.7 macrophages

A20 was originally characterized as a TNF-inducible gene in human umbilical vein endothelial cells. As an NF-kappaB target gene, A20 is also induced in many other cell types by a wide range of stimuli. Expression of A20 has been shown to protect from TNF-induced apoptosis and also functions via a negative-feedback loop to block NF-kappaB activation induced by TNF and other stimuli. To date, there are no reports on whether A20 can protect OxLDL-induced apoptosis in macrophages. For the first time we report that A20 expression blocks OxLDL-mediated cell toxicity and apoptosis. OxLDL induced the expression of Fas and FasL, and the subsequent caspase-8 cleavage and treatment with a neutralizing ZB4 anti-Fas antibody blocked apoptosis induced by OxLDL. Expression of dominant negative FADD efficiently prevented OxLDL-induced apoptosis and caspase-8 activation. A20 expression significantly attenuated the increased expression of Fas and FasL, and Fas-mediated apoptosis. These findings suggest that A20-mediated protection from OxLDL may occur at the level of Fas/FADD-caspase-8 and be FasL dependent. Treatment of RAW264.7 cells with OxLDL induces a series of time-dependent events, including the release of cytochrome c, Smac and Omi from the mitochondria to the cytosol, activation of caspase-9, -6, -2, and -3, which are blocked by A20 expression. No cleaved form of Bid was detected, even treatment with OxLDL for 48 h. Expression of dominant negative FADD also efficiently prevented OxLDL-induced the above apoptotic events. The release of cyto c, Smac and Omi from mitochondria to cytosol, activated by OxLDL treatment, and the activation of caspase-9 may not be a downstream event of caspase-8-mediated Bid cleavage. Therefore, the protective effect of A20 on mitochondrial apoptotic pathway activated by OxLDL may be dependent on FADD. A20 expression reversed OxLDL-mediated G(0)/G(1) stage arrest by maintaining the expression of cyclin B1, cyclin D1, and cyclin E, and p21 and p73. Thus, A20 expression blocks OxLDL-mediated apoptosis in murine RAW264.7 macrophages through disrupting Fas/FasL-dependent activation of caspase-8 and the mitochondria pathway.

Epigallocathechin-3 gallate inhibits cardiac hypertrophy through blocking reactive oxidative species-dependent and -independent signal pathways

Cardiac hypertrophy is a major cause of morbidity and mortality worldwide. Recent in vitro and in vivo studies have suggested that reactive oxygen species (ROS) may play an important role in cardiac hypertrophy. It was therefore thought to be of particular value to examine the effects of antioxidants on cardiac hypertrophy. Epigallocatechin-3-gallate (EGCG) is a major bioactive polyphenol present in green tea and a potent antioxidant. The current study was designed to test the hypothesis that EGCG inhibits cardiac hypertrophy in vitro and in vivo. In this study, we investigated the effects of EGCG on angiotensin II- (Ang II) and pressure-overload-induced cardiac hypertrophy. Our results showed that EGCG attenuated Ang II- and pressure-overload-mediated cardiac hypertrophy. Both reactive oxygen species generation and NADPH oxidase expressions induced by Ang II and pressure overload were suppressed by EGCG. The increased hypertension by pressure overload was almost completely blocked after EGCG treatment. Further studies showed that EGCG inhibited Ang II-induced NF-kappaB and AP-1 activation. Inhibition of the activity of NF-kappaB was through blocking ROS-dependent p38 and JNK signaling pathways, whereas inhibition of AP-1 activation was via blocking EGFR transactivation and its downstream events ERKs/PI3K/Akt/mTOR/p70(S6K). The combination of these actions resulted in repressing the reactivation of ANP and BNP, and ultimately preventing the progress of cardiac hypertrophy. These findings indicated that EGCG prevents the development of cardiac hypertrophy through ROS-dependent and -independent mechanisms involving inhibition of different intracellular signaling transductional pathways.

Adjustability of the circadian clock in the cockroaches: a comparative study of two closely related species, Blattella germanica and Blattella bisignata

A single 2h light pulse (250 lux) was given at various times to phase shift the locomotor circadian rhythm of two species of closely related cockroaches, Blattella bisignata and Blatella germanica. The phase-response curve (PRC) of both species showed a similar pattern. Phase delays and advances were induced by light pulse during the early and late subjective night, respectively, while no clear phase shifting was elicited during the subjective day. However, the magnitude of the phase delay (1.89h +/- 0.66h) and advance (0.69h +/- 0.36h) of B. bisignata was significantly larger than that of B. germanica (0.78h +/- 0.38h and 0.35h +/- 0.18h, respectively). This result indicates the superior adjustability of the circadian clock in B. bisignata. The period-response curve (PdRC) was also constructed for both species. Although both species did not show great flexibility in circadian period changes, the phase shifts were significantly correlated with the period changes in the advance zone of B. bisignata (r = 0.72, P < .1). This allowed the circadian clock of B. bisignata to display better entrainability since the phase advance adjustment was significantly more difficult than that of phase delay. The results indicate the overall adjustability of the circadian clock of B. germanica is inferior to that of B. bisignata. The significance of this finding is discussed from an ecological perspective.

Fluorescence quenching of ethidium ion by porphyrin cations and quaternary ammonium surfactants in the presence of DNA

Fluorescence quenching of free and DNA-bound ethidium bromide (EB) by a number of quaternary ammonium and other compounds was studied. For free EB or bound EB at lower DNA concentration the fluorescence quenching follows the Stern-Volmer equation and at higher DNA concentration follows an exponential model. At least at low quencher concentrations the quenching efficiency varies with DNA or NaCl concentrations and is about 100 times greater for bound than free EB. The quenching pathways may involve energy transfer and conformational loosening or distortion of the DNA helix in addition to possible electron transfer.

Inhibitory effect of triptolide on colony formation of breast and stomach cancer cell lines

Triptolide (Tri) is a diterpenoid triepoxide isolated from Tripterygium wilfordii Hook F. The effects of Tri on the colony formation of breast cancer cell lines MCF-7 and BT-20, stomach cancer cell lines MKN-45, MKN-7, and KATO-III, and promyelocytic leukemia cell line HL-60 were reported. Using Hamburger-Salmon's double layer agar technique with certain modifications, cancer cells were cultured in 0.3% agar in a highly humidified atmosphere of 5% CO2 at 37 degrees C for 14-21 d. Colonies were counted on d 14 (occasionally d 21) with the colony analyzer system CA-7A. Of the 5 solid tumor cell lines tested, 4 showed diminished colony formation in soft agar by greater than 70% of control value in Tri 10(-8) mol.L-1 (continuous exposure). The magnitudes of the inhibitory effect of Tri on most breast and stomach cancer cell lines were similar to that on the leukemia cell line HL-60. IC50 were 0.504-1.22 micrograms.L-1. The clinically achievable peak plasma concentration (PPC) of Tri was estimated as 0.15 mg.L-1, being 72-126 times higher than the IC70 of the cancer cell lines except KATO-III. The results suggest that Tri might have a potential therapeutic effect on some types of solid tumors, e.g., breast and stomach cancers.