Levosimendan alleviates coronary microembolization-induced myocardial injury through LOX-1/p38 MAPK pathway / 中华急诊医学杂志

Objective:To study the effect of levosimendan on coronary microembolization (CME)-induced myocardial injury and LOX-1/p38MAPK pathway.Methods:Microspheres were injected into coronary anterior descending branch to construct swine CME model, swine was given levosimendan by continuous intravenous drip for 24 h before modeling, and myocardial-specific overexpression of lectin-like oxidized low density lipoprotein receptor 1 (LOX-1) was achieved through coronary artery injection of adeno-associated virus (AAVs) at 2 weeks before modeling. Then, echocardiography was used to measure cardiac function; HE staining and HBFP staining were used to observe the pathological changes of myocardium and myocardial microinfarction area, respectively; ELISA was used to detect the serum level of cTnI; TUNLE staining was used to detect cardiomyocyte apoptotic index; the LOX-1, Bax, caspase-3 p12, Bcl-2, and p-p38 MAPK protein in myocardial tissue was observed by immunofluorescence method.Results:Compared to the sham group, the LVEF, LVFS, and CO value in the CME group were decreased, while the LVEDd value was increased significantly (all P<0.05); the area of myocardial micro-infarction, serum cTnI level and cardiomyocyte apoptotic rate in the CME group were increased significantly (all P<0.05); the protein levels of Bax, caspase-3 p12, LOX-1, and p-p38 MAPK were increased significantly, while the Bcl-2 level was decreased significantly ( P<0.05). Levosimendan pretreatment significantly improved cardiac dysfunction, reduced the area of myocardial micro-infarction and serum cTnI level, alleviated cardiomyocyte apoptosis, and significantly reduced the LOX-1 and p-p38 MAPK protein expression levels following CME (all P<0.05); while pretreatment with levosimendan and LOX-1 overexpression AAVs simultaneously abolished the effects of pretreatment with levosimendan alone (all P<0.05). Conclusion:Levosimendan alleviates CME-induced myocardial injury through inhibiting cardiomyocyte apoptosis mediated by LOX-1/p38 MAPK signaling pathway.

Study on visfatin-induced inflammation and necroptosis via LOX-1 in human umbilical vein endothelial cells / 生物医学工程学杂志

The aim of the study is to identify the effects and underlying mechanisms of visfatin on inflammation and necroptosis in vascular endothelial cells. Human umbilical vein endothelial cells (HUVECs) were stimulated with visfatin or pretreated with Polyinosinic acid (LOX-1 inhibitor). By using the Western blot, RT-PCR, immunocytochemistry, enzyme-linked immunosorbent assay (ELISA), MTT and flow cytometry technique, the occurrence of inflammation and necroptosis in HUVECs were evaluated. Our results showed that 100 ng/mL visfatin significantly increased the mRNA and protein expression of monocyte chemotactic protein 1 (MCP-1) and LOX-1 after 24 hours' treatment in HUVECs. However, pretreatment with Polyinosinic acid could significantly reduce the expression of MCP-1 compared with visfatin group. Additionally, 100 ng/mL visfatin could induce the production of necrotic features and increase the mRNA expression of BMF (one of the markers of necroptosis), while pretreating with Polyinosinic acid markedly downregulated the mRNA expression of BMF gene and promoted the cell proliferation. These results indicate that visfatin might induce inflammation and necroptosis via LOX-1 in HUVECs, suggesting that visfatin plays a central role in the development of atherosclerosis.

Effects of Gualou Xiebai Banxia decoction on blood lipid content, oxidative stress and ox-LDL/Lox-1 pathway in ApoE-/- mice / 中国中药杂志

To observe the functions of Gualou Xiebai Banxia decoction（GXBD） on regulating lipid metabolism, anti-oxidation, and interposing ox-LDL/Lox-1 pathway, and to explore its anti-atherosclerosis (AS) mechanisms. AS models were established by using 42 Apo-E-/- male mice with high fat diet. AS model mice were randomly divided into the model group, simvastatin group, and GXBD high and low dose groups. C57BL/6J male mice were used as the normal control group, n=10 and the treatment lasted for 8 weeks. The levels of TC, TG, LDL-C, HDL-C, SOD, MDA, GSH-px, and ox-LDL in blood serum were tested 24 h after the last administration. The changes of aortic tissues structure were observed by HE staining; the expression levels of Lox-1 protein and the expression levels of mRNA were detected by Western blot and PCR respectively.Results showed that the blood lipid levels and MDA, ox-LDL levels in blood serum of model group were significantly higher than those in the normal control group, but SOD, GSH-px levels were significantly lower than those in the normal control group, and the Lox-1 protein and mRNA expression levels were also significantly higher than those in the control group(P<0.05), namely aortic atherosclerosis lesions were obvious in model group.The levels of blood lipid and MDA, ox-LDL of GXBD high and low dose groups and simvastatin group were significantly lower than those in model group, while SOD, GSH-px levels were significantly higher than those in model group, and Lox-1 protein and mRNA expression levels were significantly lower than those in model group(P<0.05), namely the aortic atherosclerosis lesions were significantly relieved. The above results indicated that GXBD was capable of modulating blood lipid, anti-oxidation, and inhibiting the expression of Lox-1, and interposing ox-LDL/Lox-1 pathway in the AS model Apo-E-/- mice, which may be one of the mechanisms of anti-atherosclerosis.

Efectos inflamatorios, oxidativos y aterogénicos del receptor endotelial de la lipoproteína de baja densidad oxidada-1 / Inflammatory, oxidative and atherogenic effects of endothelial lectin-like receptor of oxidized low density lipoprotein-1 / Efeitos inflamatórios, oxidativos e aterogênicos do receptor endotelial da lipoproteína de baixa densidade oxidativa-1

LOX-1 es un receptor endotelial de la familia de las lectinas. Su actividad biológica tiene un fuerte impacto en los fenómenos inflamatorios, oxidativos y aterogénicos endoteliales. Cuando se conoció el receptor de la lipoproteína de baja densidad (RLDL) y su regulación, se afirmó el papel aterogénico del colesterol transportado en esta lipoproteína (C-LDL). Este papel de las lipoproteínas fue la base de la denominación de dislipoproteinemias en reemplazo de dislipemias. En condiciones post-prandiales, las lipoproteínas ricas en triglicéridos, como quilomicrones y lipoproteínas de muy baja densidad (VLDL), son degradadas por la lipoproteína lipasa (LPL) de la pared vascular, produciéndose remanentes de quilomicrones (RQ) y lipoproteínas de densidad intermedia (IDL), respectivamente, que en conjunto se denominan lipoproteínas remanentes (RLPs). Dependiendo del estrés oxidativo las RLPs son oxidables y pueden unirse al LOX-1. También se liberan ácidos grasos que injurian células endoteliales y contribuyen a abrir brechas en el endotelio, que en condiciones fisiológicas es una barrera de células con uniones estrechas. El dominio intracelular de LOX-1 regula el reconocimiento de lipoproteínas de baja densidad oxidadas (LDLOX) y de RLPs. Además, posee un efecto dependiente de los radicales reactivos de oxígeno (ROS). Su dominio transmembrana actúa en el pasaje de LDLOX y monocitos al subendotelio. La inhibición de LOX-1 con anticuerpos específicos impide su unión con LDLOX, restableciendo la barrera entre el lumen vascular y el subendotelio. En cambio, las LDLOX unidas al dominio transmembrana, producen apoptosis de las células endoteliales y suprimen uniones estrechas intercelulares en el endotelio, facilitando la actividad de las moléculas de adhesión leucocitarias que promueven el pasaje al subendotelio de los elementos del lumen, tales como monocitos, plaquetas, LDLOX, RLPs oxidables y lipoproteínas (a) (Lp(a)) semejantes al plasminógeno. Las LDLOX subendoteliales aumentan la movilidad de células musculares lisas. Los monocitos subendoteliales se establecen como residentes, e incorporan LDLOX, convirtiéndose sucesivamente en macrófagos, células espumosas y lesiones aterogénicas. Sin embargo, desde Assmann G y su estudio PROCAM no puede ignorarse el papel de los triglicéridos y colesterol de lipoproteínas de alta densidad (C-HDL) como componentes del cuadro de riesgo en ECV.

LOX-1 is an endothelial receptor belonging to the family of lectins. Its biological activity has a strong impact on inflammatory, oxidative and atherogenic phenomena in endothelium. When Low Density Lipoprotein receptor (RLDL) and its regulation were known, the atherogenic role of the cholesterol transported in LDL (LDL-C) was confirmed. This lipoprotein role in atherosclerosis was the base to use the term dyslipoproteinemia instead of dyslipidemia. In post-prandial conditions, triglyceride-rich lipoproteins like chylomicrons and very low-density lipoproteins (VLDL), are degraded by lipoprotein lipase (LPL) on the vascular wall, with the resultant formation of chylomicron remnants (CR) and intermediate density lipoproteins (IDL) respectively, which as a whole are called remnant lipoproteins (RLPs). Depending on oxidative stress, RLPs are oxidized and then they can bind the LOX-1. In this process, fatty acids are also released, injuring endothelial cells and contributing to open gaps in endothelium, which under physiological conditions, is a barrier of cells with tight junctions. The intracellular domain of LOX-1 regulates the recognition of oxidized LDL (oxLDL) and RLPs, and its effect depends on reactive oxygen species (ROS). LOX-1 transmembrane domain acts in the passage of oxLDL and monocytes to the sub-endothelium. Inhibition of LOX-1 by specific antibodies prevents its binding with OxLDL, restoring the barrier between the vascular lumen and sub-endothelium. By contrast, the oxLDL, attached to the transmembrane domain, produce apoptosis of endothelial cells and the suppression of narrow intercellular junctions in the endothelium. Thus, enabling the activity of leucocyte adhesion molecules that promote the transfer to subendothelial elements lumen of monocytes, platelets, oxLDL, oxidized RLPs and lipoprotein (a) (Lp (a)), similar to plasminogen such as. Sub-endothelial OxLDL increase the mobility of smooth muscle cells. Sub-endothelial monocytes establish as resident, up-take oxLDL and successively become into macrophages, foam cells and atherosclerotic lesions. However, since Assman’s PROCAM study, the role of triglycerides and High Density Lipoprotein-cholesterol (HDL-C), as components of cardiovascular risk, cannot be ignored.

LOX-1 é um receptor endotelial da família das lectinas. Sua atividade biológica tem um importante impacto nos fenômenos inflamatórios, oxidativos e aterogênicos endoteliais. Quando foi conhecido o receptor da lipoproteína de baixa densidade (RLDL) e sua regulação, afirmou-se o papel aterogênico do colesterol transportado nesta lipoproteína (C-LDL). Este papel das lipoproteínas foi a base da denominação de dislipoproteinemias em substituição de dislipidemias. Em condições pós-prandiais, as lipoproteínas ricas em triglicérides como quilomícrons e Lipoproteínas de muito baixa densidade (VLDL) são degradadas pela lipoproteína lipase (LPL) da parede vascular, produzindo remanescentes de quilomícrons (RQ) e lipoproteínas de densidade intermediária (IDL) respectivamente, que em conjunto são chamadas lipoproteínas remanescentes (RLPs). Dependendo do estresse oxidativo, as RLPs são oxidáveis e podem se ligar ao LOX-1. Também são liberados ácidos graxos que injuriam células endoteliais e contribuem na abertura de fendas no endotélio, que em condições fisiológicas é uma barreira de células com uniões estreitas. O domínio intracelular de LOX-1 regula o reconhecimento de lipoproteínas de baixa densidade oxidativa (LDLOX) e de RLPs. Também possui um efeito dependente dos radicais reativos de oxigênio (ROS). Seu domínio transmembrana atua na passagem de LDLOX e monócitos para o subendotélio. A inibição de LOX-1 com anticorpos específicos impede sua união com LDLOX restabelecendo a barreira entre o lúmem vascular e o subendotélio. Entretanto, as LDLOX ligadas ao domínio transmembrana produzem apoptose das células endoteliais e suprimem estreitas junções intercelulares no endotélio, facilitando a atividade das moléculas de adesão leucocitária que promovem a passagem para o subendotélio de elementos do lúmem, tais como monócitos, plaquetas, LDLOX, RLPs oxidáveis e lipoproteínas (a) [Lp(a)] semelhantes ao plasminogênio. As LDLOX subendoteliais aumentam a mobilidade das células musculares lisas. Os monócitos subendoteliais se estabelecem como residentes, e incorporam LDLOX, virando sucessivamente em macrófagos, células espumosas e lesões aterogênicas. No entanto, desde Assman G e seu estudo PROCAM, não pode se ignorar o papel dos triglicérides e do colesterol de lipoproteínas de alta densidade (C-HDL) como componentes do evento de risco em ECV.

Lectin-Like Oxidized LDL Receptor 1 Mediates the Uptake of the C-Terminal Domain of Hsp70 (A Promising Immune Adjuvant Molecule) and Antigen Peptide Complexes.

Extracellular heat shock protein 70 (Hsp70) is an adjuvant molecule that stimulates the immune system. The C-terminal domain of Hsp70 (C70), without the ATPase domain, is sufficient for antigen cross-presentation. However, the mechanism by which the receptor mediates the uptake of C70–peptide complex remains unclear. We therefore aimed to determine the process by which the receptor mediates the uptake of antigenic peptide-bound C70. Methodology: Hsp70 and C70 individually cloned into pET28a were expressed in Escherichia coli BL21 (DE3) and were purified on Ni-NTA agarose and MonoQ HR5/5. Hsp70 and C70 were labeled with Alexa 555 and Alexa 633, respectively, to detect cellular binding. HEK293 cells stably expressing lectin-like oxidized LDL receptor-1 (LOX 1) and KG-1 human dendritic-like cells were incubated with Alexa-labeled Hsp70 and C70 individually or with C70 and antigenic complexes and were observed using fluorescence microscopy. The affinity of LOX-1 toward Hsp70 and C70 was analyzed by chip assay using surface plasmon resonance, which immobilized LOX-1 ligand recognition domain. Results: HEK293 cells stably expressing LOX-1 and KG-1 cells accepted the C70– peptide and Hsp70–peptide complexes. Anti-LOX-1-neutralizing antibody inhibited the uptake of the C70–peptide complexes by KG-1 cells. The dissociation constant (KD) of C70 toward the LOX-1 extracellular domain, measured by surface plasmon resonance, was 4.02 × 10−7 M and that of the C70–peptide complex was 6.6 × 10−8 M. C70 increased the LOX-1 affinity by forming a complex with the antigen peptide. Conclusion: Our findings suggest that LOX-1 is the primary receptor for the C70–peptide and the Hsp70–peptide complexes. C70 is a promising adjuvant molecule that is internalized via LOX-1. In addition, it is convenient to prepare C70 using an E. coli expression system and C70 is more stable than full-length Hsp70.

Effect of Tangshenning on Renal Function and LOX-1 mRNA Expression in Early DN Rats Model / 中国药师

Objective:To observe the effect of Tangshenning on renal function and LOX-1 mRNA expression in the kidney of early diabetic nephropathy rats model. Methods:Early diabetic nephropathy rats model was made with high fat diet, STZ and unilateral ne-phregtomy. After the 12-week drug intervention, the rats were sacrificed, the kidneys were removed and the mRNA expressions of LOX-1 in the kidney were observed by the method of RT-PCR. Results:Early diabetic nephropathy rats model was successfully made by the triple-modeling method. The mRNA expression of LOX-1 in the kidney was significantly increased, and Tangshenning could low-er the expression of LOX-1 in the kidney in a dose-dependent manner. Conclusion:The abnormal expression of LOX-1 could be one of the mechanisms for diabetic nephropathy. Tangshening has good kidney protective effect through decreasing LOX-1 abnormal expression in the kidneys, which deserves further research.

Ox-LDL increases OX40L in endothelial cells through a LOX-1-dependent mechanism

Oxidative low-density lipoprotein (Ox-LDL) is a key risk factor for the development of atherosclerosis, and it can stimulate the expression of a variety of inflammatory signals. As a new and highly sensitive inflammation index, OX40L may be a key to understanding the mechanisms that regulate interactions between cells within the vessel wall and inflammatory mediators during the development of atherosclerosis. To investigate whether Ox-LDL regulates OX40L expression through an oxidized LDL-1 receptor (LOX-1)-mediated mechanism, we investigated the effect of different concentrations of Ox-LDL (50, 100, 150 µg/mL) on endothelial cell proliferation and apoptosis. Stimulation with Ox-LDL increased OX40L protein 1.44-fold and mRNA 4.0-fold in endothelial cells, and these effects were inhibited by blocking LOX-1. These results indicate that LOX-1 plays an important role in the chronic inflammatory process in blood vessel walls. Inhibiting LOX-1 may reduce blood vessel inflammation and provide a therapeutic option to limit atherosclerosis progression.

Effects of Tangshentang on the expression of LOX-1 and secretion of extracellular matrix induced by ox-LDL in rat masengial cells / 中华中医药杂志

Objective: To investigate the effect of Tangshentang on the expression of LOX-1 and secretion of TGF-?1,FN,ColⅣ in cultured rat masengial cells(RMCs) induced by ox-LDL and to explore its molecular mechanism of preventing and treating diabetic nephropathy.Methods: The cultured RMCs were divided into control group,ox-LDL group,Tangshentang group(respectively high,medium and low group)and rosiglitazone group.The mRNA expression was tested by RT-PCR.Synthesis of TGF-?1,FN,ColⅣ in cultured RMCs were determined by ELISA methods.Results: Tangshentang drug serum significantly attenuated up-regulation of TGF-?1,LOX-1 mRNA expression and synthesis of TGF-?1,FN,ColⅣ in a dose-dependent manner,with the peak at middle concentration,in RMCs stimulated by ox-LDL(50?g/ml).Conclusion: Tangshentang drug serum may protect kidney from injury by ox-LDL via the decreased expression of LOX-1 to reduce the uptake of ox-LDL and subsequently inhibiting TGF-?1 secretion,as well as the deposition of FN,ColⅣ.

The progress in LOX-1 research / 中国药理学通报

Lectin like oxidized low density lipoprotein receptor 1(LOX 1) is a type Ⅱ membrane protein belonging to the C type lectin family molecules which can act as a cell surface endocytosis receptor for oxidized LDL.LOX 1 can support binding, internalization and proteolytic degradation of oxidized LDL. And LOX 1 is involved in the platelet endothelium interaction and mediates phagocytosis of aged/apoptotic cells in endothelial cells ox LDL. Purification of soluble LOX 1 and the N terminal amino acid sequencing identified the two cleavage sites (Arg 86 Ser 87 and Lys 89 Ser 90 ). LOX 1 expression is not constitutive, but can be induced by proinflammatory stimuli, such as Angiotension Ⅱ, fluid shear stress and so on.

Effects of candesartan on aorta oxidative stress-LOX-1 pathway in salt-loaded stroke-prone spontaneously hypertensive rats / 中国药理学通报

Aim To investigate the effects of an angiotensin Ⅱ receptor blocker,candesartan, on aorta oxidative stress-LOX-1 pathway in salt-loaded stroke-prone spontaneously hypertensive rats (SHRSP).Methods 12-week-old salt-loaded SHRSP were treated with candesartan(1.0 mg?kg-1?d-1)or a diuretic, trichlormethiazide(TCM,1.6 mg?kg-1?d-1) or no treatment(n=6) in each for 2 weeks. Age-matched salt-loaded WKY rats were served as control(n=6).Systolic blood pressure(SBP)was measured weekly throughout the 2-week period by means of the tail-cuff method.Thoracic aortas were extracted and 24 h urine was collected.NAD(P)H oxidase subunits(p22 phox, p47 phox and gp91 phox)mRNA expression in aorta were assayed by real-time PCR. LOX-1 and type Ⅳ collogen mRNA expression were examined by RT-PCR. gp91 phox and LOX-1 protein expression in aorta were assayed by immunohistochemistry.Urinary albumin excretion was examined by ELISA.Results At the end of the 2nd week, SBP was significantly higher in salt-loaded SHRSP than that in salt-loaded WKY rats. Treatment with candesartan and TCM significantly decreased SBP in salt-loaded SHRSP at similar levels.NAD(P)H oxidase subunits (p47 phox and gp91 phox)and LOX-1 mRNA expression in aorta were markedly higher in salt-loaded SHRSP than those in salt-loaded WKY rats.Candesartan and TCM had the effect of reducing the systolic blood pressure at similar levels. Candesartan significantly down-regulated aorta p22 phox, gp91 phox,LOX-1 and type Ⅳ collogen mRNA expression and decreased urine albumin excretion in salt-loaded SHRSP(P