LOX-1 deletion and macrophage trafficking in atherosclerosis

Background

Atherosclerosis is associated with macrophage accumulation. LOX-1 has been shown to induce macrophage attachment, and its deletion (LOX-1 knockout, KO) reduces atherosclerosis in LDLr KO mice fed a high cholesterol diet. We examined differences in macrophage trafficking in age-matched wild type, LOX-1 KO, LDLr KO, and LDLr/LOX-1 double KO mice.

Methods

Sections of aortas of mice fed high cholesterol diet were collected at weeks 0, 4, 8, 12 and 19 and analyzed by immunohistochemistry and flow cytometry.

Results

In the LDLr KO mice aorta, CD68 positivity (macrophage accumulation) increased over time up to 12 weeks, and then the accumulation fell modestly but significantly. The periaortal fat and adventitia showed more CD68 positivity than the media and intima. This pattern was also evident in the non-atherosclerotic areas. Importantly, LOX-1 KO and LDLr–LOX-1 double KO mice showed diminished CD68 positivity in comparison to wild type and LDLR KO mice, respectively. Further, macrophages from LOX-1 KO mice revealed a marked reduction in migration (vs. macrophages from wild type mice) in in vitro migration assay.

Conclusions

LOX-1 deletion translates into reduction in macrophage trafficking in the aorta of LDLr KO mice. Most of the macrophage trafficking appears in the subadventitial regions.     

3种苯并咪唑类药物对大熊猫西氏贝蛔虫的驱虫效果初步观察

西氏贝蛔虫Baylisascaris schroederi是圈养大熊猫Ailuropoda melanoleuca最常见、危害最严重的一种体内寄生虫,采用药物驱虫是目前控制圈养大熊猫蛔虫病的主要措施。为了筛选有效的驱虫药物,本研究观察了3种苯并咪唑类药物(阿苯达唑片剂、芬苯达唑膏剂和甲苯咪唑片剂)对大熊猫蛔虫的驱虫效果,统计了驱虫前后粪检蛔虫卵转阴率及排虫情况。结果表明,除芬苯达唑按5 mg·kg^-1体质量口服,每天1次,连续服用2 d,效果较差外,3种药物按10 mg·kg^-1体质量口服,每天1次,连续服用2 d,用药安全且有较好的驱虫效果。     

Degradation of heparan sulfate proteoglycans enhances oxidized-LDL-mediated autophagy and apoptosis in human endothelial cells

BackgroundCell surface heparan sulfate proteoglycans (HSPG) play an important role in atherogenesis. We hypothesized that degradation of HSPG may increase the binding of atherogenic oxidized low density lipoprotein (ox-LDL) to endothelial cells, and result in extensive HSPG degradation as well as autophagy and apoptosis.MethodsPrimary human umbilical vein endothelial cells (HUVECs) were used to study the expression of lectin-like ox-LDL receptor-1 (LOX-1), HSPG, autophagy and apoptosis in response to ox-LDL and heparinase III (Hep III).ResultsAs expected, ox-LDL treatment resulted in LOX-1 expression, ox-LDL uptake and reactive oxygen species (ROS) generation. Ox-LDL treatment also resulted in a modest degradation of HSPG and increase in autophagy (expression of LC3, beclin-1 and Atg5) and apoptosis (enhanced expression of caspases and Bax, and reduced expression of Bcl-2 and Bcl-xL). The effects of ox-LDL were blocked by pretreatment of cells with LOX-1 antibody or apocynin, an NADPH oxidase inhibitor. Hep III alone caused HSPG degradation and slightly, but significantly, increased ROS generation, and induced autophagy and caspase expression. However, autophagy and apoptosis induced by Hep III were not affected by apocynin or LOX-1 antibody. Importantly, Hep III pretreatment of cells significantly enhanced ox-LDL-induced HSPG degradation, LOX-1 expression, ox-LDL uptake and ROS generation as well as autophagy and apoptosis.ConclusionThese data demonstrate that Hep III enhances the pro-atherosclerotic characteristics in HUVECs induced by ox-LDL.     

Effect of LDL concentration polarization on the uptake of LDL by human endothelial cells and smooth muscle cells co-cultured

To substantiate our hypothesis that concentration polarization of low-density Upoprotein （LDL） plays an important role in the localization of atherogenesis, we investigated the effects of wall shear stress and water filtration rate （or perfusion pressure） on the luminal surface LDL concentration （cw） and the LDL uptake by human vascular endothelial cells and smooth muscle cells co-cultured on a permeable membrane using a parallel-plate flow chamber technique and a flow cyto-metry method. The results indicated that the uptake of fluorescent labeled LDL （DiI-LDL） by the co-cultured cells was positively correlated with Cw in a non-linear fashion. When cw was low, the uptake increased very sharply with increasing Cw. Then the increase became gradual and the uptake was seemingly leveled out when Cw reached beyond 160 μg/ml. The present study therefore has provided further experimental evidence that concentration polarization may occur in the arterial system and have a positive correlation with the uptake of LDLs by the arterial wall, which gives support to our hypothesis regarding the localization of atherogenesis.     

Delineation of the effects of angiotensin type 1 and 2 receptors on HL-1 cardiomyocyte apoptosis

Angiotensin II (Ang II) exerts its effects by activating its receptors, primarily type 1 (AT1R) and type 2 (AT2R). While the role of AT1R activation in cardiomyocyte physiology is well known, the role of AT2R in cardiomyocyte apoptosis remains controversial. To define the precise role of AT1R and AT2R in this process, we transfected HL-1 cardiomyocytes with AT1R or AT2R cDNA, and examined markers of apoptosis. We found that AT1R overexpression was associated with upregulation of endogenous AT2R expression, but AT2R overexpression did not affect endogenous AT1R expression. Caspase-3 staining indicated that overexpression of AT1R as well as AT2R resulted in cardiomyocyte apoptosis with appropriate alterations in annexin V, Bax and Bcl2 expression. Overexpression of AT1R and AT2R markedly increased IL-1β (AT2R>AT1R), iNOS (AT2R>AT1R) and eNOS expression. AT2R-induced cell apoptosis could be blocked by the iNOS selective inhibitor 1,400?W, and did not require exogenous Ang II. These findings suggest that AT2R overexpression induces cardiomyocyte apoptosis, most likely via iNOS upregulation. AT1R-mediated cardiomyocyte apoptosis may be partially mediated by upregulation of endogenous AT2R.     

Upregulation of 3-MST Relates to Neuronal Autophagy After Traumatic Brain Injury in Mice

3-mercaptopyruvate sulfurtransferase (3-MST) was a novel hydrogen sulfide (H₂S)-synthesizing enzyme that may be involved in cyanide degradation and in thiosulfate biosynthesis. Over recent years, considerable attention has been focused on the biochemistry and molecular biology of H₂S-synthesizing enzyme. In contrast, there have been few concerted attempts to investigate the changes in the expression of the H₂S-synthesizing enzymes with disease states. To investigate the changes of 3-MST after traumatic brain injury (TBI) and its possible role, mice TBI model was established by controlled cortical impact system, and the expression and cellular localization of 3-MST after TBI was investigated in the present study. Western blot analysis revealed that 3-MST was present in normal mice brain cortex. It gradually increased, reached a peak on the first day after TBI, and then reached a valley on the third day. Importantly, 3-MST was colocalized with neuron. In addition, Western blot detection showed that the first day post injury was also the autophagic peak indicated by the elevated expression of LC3. Importantly, immunohistochemistry analysis revealed that injury-induced expression of 3-MST was partly colabeled by LC3. However, there was no colocalization of 3-MST with propidium iodide (cell death marker) and LC3 positive cells were partly colocalized with propidium iodide. These data suggested that 3-MST was mainly located in living neurons and may be implicated in the autophagy of neuron and involved in the pathophysiology of brain after TBI.     

Antiproliferation and apoptosis of human tumor cell lines by a lectin (AMML) of Astragalus mongholicus

A lectin (AMML) from the roots of Astragalus mongholicus was extracted and purified by affinity chromatographic technique. Human cervical carcinoma cell line (HeLa), human osteoblast-like cell line (MG63) and human leukemia cell line (K562) were used to check the effects of AMML on cell proliferation, apoptosis and cell cycle. Maximum growth inhibition (92%) was observed with HeLa cells, followed by K562 cells (84%) and MG63 (48%) cells. Morphological observation showed that AMML-treated HeLa cells displayed outstanding apoptosis characteristics, such as nuclear fragmentation and appearance of membrane-enclosed apoptotic bodies. The apoptosis of HeLa cells was confirmed by flow cytometry using Annexin V/FITC and propidium iodide (PI) staining technique. For the first time we also report a significant cell cycle arrest at S phase of HeLa cells by AMML. Therefore, the present investigation may lead to the possible therapeutic use of Astragalus mongholicus lectin.     

湘西辣蓼挥发油化学成分的研究

利用气相色谱-质谱联用仪对湘西辣蓼草中的挥发油化学成分进行了研究,共鉴定出53种组分.其主要成分为1-菲兰烯、1-异丙烯基-?-甲基苯、姜烯、α-苎烯、β-石竹烯、α-蒎烯、γ-松油烯、香柠檬烯、律草烯、红没药烯等.其中1-菲兰烯含量最高.约占挥发油总量的14%.     

MSC exosome-mediated cardioprotection in ischemic mouse heart comparative proteomics of infarct and peri-infarct areas

Molecular and Cellular Biochemistry - Mesenchymal stem cell (MSC) exosomes may limit cardiac injury, and even reverse cardiac damage in animal models of ischemia. To understand exosome-mediated...