Concurrent therapies that protect against doxorubicin-induced cardiomyopathy

Doxorubicin is a chemotherapeutic agent successfully used in the treatment of a wide range of cancers. However, with cumulative doses, doxorubicin also is known to have cardiotoxic effects, including cardiomyopathy and heart failure. Research is targeted at maximizing the antitumor effects of doxorubicin while attenuating the potential cardiotoxicity. Concurrent therapies under study are combinations of doxorubicin with drugs such as probucol, carvedilol (Coreg, GlaxoSmithKline, Research Triangle Park, NC), dexrazoxane (Zinecard, Pfizer, New York, NY), and antioxidant nutrients. As patient advocates, nurses must be aware of current research, treatment options, and evidence-based patient resources and be diligent in assessing and educating patients before, during, and after treatment with doxorubicin.     

促红细胞生成素对阿霉素性心肌病大鼠心肌Bax和Bcl-2表达的影响

目的:观察凋亡相关蛋白Bax和Bcl-2在阿霉素(DOX)性心肌病大鼠心肌中的表达,探讨促红细胞生成素(EPO)保护阿霉素性心肌病大鼠的机制。方法:31只雄性Wistar大鼠随机分为对照组、DOX组和DOX+EPO组。药物干预4周后,观察各组大鼠一般情况,进行超声心动图和心肌病理学检查,采用免疫组化和RT-PCR检测Bax与Bcl-2的蛋白和mRNA表达水平。结果:DOX组大鼠符合阿霉素性心肌病表现,DOX+EPO组大鼠左心功能改善,心肌纤维化明显减少。与DOX组相比较,EPO治疗(DOX+EPO组)未能降低Bax蛋白和mRNA表达水平,但显著升高了Bcl-2的表达水平(P<0.05)。结论:EPO对阿霉素性心肌病具有良好的保护作用,这可能与其上调Bcl-2蛋白和mRNA表达有关。     

Carvedilol protects bone marrow stem cells against hydrogen peroxide-induced cell death via PI3K-AKT pathway

Carvedilol, a nonselective β-adrenergic receptor blocker, has been reported to exert potent anti-oxidative activities. In the present study, we aimed to investigate the effects of carvedilol against hydrogen peroxide (H₂O₂)-induced bone marrow-derived mesenchymal stem cells (BMSCs) death, which imitate the microenvironment surrounding transplanted cells in the injured spinal cord in vitro. Carvedilol significantly reduced H₂O₂-induced reactive oxygen species production, apoptosis and subsequent cell death. LY294002, the PI3K inhibitor, blocked the protective effects and up-regulation of Akt phosphorylation of carvedilol. Together, our results showed that carvedilol protects H₂O₂-induced BMSCs cell death partly through PI3K-Akt pathway, suggesting carvedilol could be used in combination with BMSCs for the treatment of spinal cord injury by improving the cell survival and oxidative stress microenvironments.     

Obestatin attenuated doxorubicin-induced cardiomyopathy via enhancing long noncoding Mhrt RNA expression

ObjectiveThe emergence of side-effect of doxorubicin in cardiomyopathy and heart failure has led to the search for diverse strategies to prevent its cytotoxic effects. This study was to determine the role of obestatin on doxorubicin-induced cardiomyocytes apoptosis and possible underlying mechanism.MethodsSprague Dawley rats were divided into 3 groups and received treatment for a total of 6 weeks: group1, untreated normal rats; group2, Doxorubicin-induced heart cardiomyopathy (DC) rats; and group3, obestatin treated HC rats. Doxorubicin (2.5 mg/kg) or obestatin (100 μg/kg/d) were discontinuously administered via intraperitoneal injection. Primary cardiomyocytes and H9C2 cell line were used for in vitro experiments. Mhrt and Nrf2 (nuclear factor erythroid 2 −related factor 2) mRNA expressions were determined using qRT-PCR. Expression of Nrf2 protein was determined using western blotting. TUNEL assay was performed to evaluate cell apoptosis.ResultsAdministration of obestatin significantly improved doxorubicin-induced dysfunction of left ventricular contractility function, moreover, resulted in upregulation of Mhrt and Nrf2 in failing myocardial tissue. Co-incubation of obestatin and doxorubicin in primary cardiomyocytes also enhanced Mhrt and Nrf2 expression as well as prevented cell apoptosis in comparison with doxorubicin only. Manipulation of cellular Mhrt by pcDNA-Mhrt or si-Mhrt transfection positively regulated Nrf2 expression in doxorubicin-incubated cardiomyocytes. Silencing Mhrt reversed cardioprotective effects of obestatin both in vivo and in vitro.ConclusionAdministration of obestatin attenuates doxorubicin-induced cardiac dysfunction via preservation of cardiomyocytes apoptosis in a Mhrt-Nrf2 dependent pathway.     

Thymoquinone protects against cardiac damage from doxorubicin-induced heart failure in Sprague-Dawley rats

Heart failure is a complex end stage result of various cardiovascular diseases, and has a poor prognosis. The mechanisms for the development and progression of heart failure have always been an important topic in cardiovascular research, and previous studies have shown that thymoquinone (TQ) protects against cardiotoxicity and cardiac damage. The aim of this study was to investigate the possible protective effects of thymoquinone against cardiac damage in doxorubicin (DOX)-induced heart failure in Sprague-Dawley Rats (SDR). Forty-five male SDR were randomly divided into three groups and administered different treatment regimens for 8 weeks. Left ventricular fractional shortening (LVFS) and ejection fraction (LVEF) were higher in the DOX + TQ group than those in the DOX group. Significant pathophysiology changes (HE and Masson staining) were observed in rats of the DOX group compared to those of the DOX + TQ group. The addition of Thymoquinone inhibited DOX-induced cardiac fibrosis (TGF-β, Smad3, collagen I, collagen III, and α-SMA) and apoptosis (P53, bcl-2, caspase-3, caspase-9, and BAX) in SDR, indicating that thymoquinone may be a potential therapeutic target for cardiac damage caused by DOX-induced heart failure.

Heart failure is a complex end stage result of various cardiovascular diseases, and has a poor prognosis.     

Myocardial strain analysis in a doxorubicin-induced cardiomyopathy model

The aim of our study was to determine if strain (S) and strain rate (SR) imaging are more sensitive indices with respect to standard echocardiographic parameters to assess cardiac function in an experimental model of doxorubicin (DOX)-induced cardiomyopathy. DOX was administered intraperitoneally 4x/wk at the dose of 1.25 mg/kg/d over four weeks in Wistar rats (n = 26). Other 14 Wistar rats were used as controls. Echocardiographic studies were performed before DOX treatment (baseline), after two and four weeks of treatment. At two and four weeks of DOX treatment, rat hearts were collected for histologic analysis. After two weeks of DOX treatment, there were no significant changes in standard echocardiographic parameters and in myocardial velocities, but after four weeks of treatment, ejection fraction significantly decreased and left ventricle dimensions significantly increased. Also, myocardial velocities were significantly reduced after four weeks of treatment. Conversely, S and SR values changed significantly already after two weeks of treatment. At baseline, S and SR values were 27 +/- 7% and 7.4 +/- 1.7, respectively, and they significantly decreased to 12 +/- 6% (p < 0.0001) and 6 +/- 1.5 (p < 0.005) at two weeks of treatment. These changes were also significant compared with control rat parameters (p < 0.001). At four weeks of DOX treatment, a progressive worsening occurred. Strain and SR further significantly decreased to 10 +/- 4% (p < 0.0001 vs. baseline) and 4.6 +/- 1.6 (p < 0.0001 vs. baseline), respectively. These changes were supported by histologic findings. Indeed, damage in myocardial tissue was demonstrated by histology already after two weeks of DOX treatment, with a damage progression after four weeks of treatment. Our data demonstrate that S and SR imaging are more sensitive indices in identifying early myocardial systolic changes induced by DOX than standard echocardiographic parameters and myocardial velocities. We believe that our model will be very supportive to further assess these new diagnostic strategies to provide a precocious diagnosis of LV dysfunction with a unique opportunity to initiate preventive cardioactive therapy. (E-mail: giodisal@yahoo.it).     

Erythropoietin protects against diabetes through direct effects on pancreatic beta cells

A common feature among all forms of diabetes mellitus is a functional β-cell mass insufficient to maintain euglycemia; therefore, the promotion of β-cell growth and survival is a fundamental goal for diabetes prevention and treatment. Evidence has suggested that erythropoietin (EPO) exerts cytoprotective effects on nonerythroid cells. However, the influence of EPO on pancreatic β cells and diabetes has not been evaluated to date. In this study, we report that recombinant human EPO treatment can protect against diabetes development in streptozotocin-induced and db/db mouse models of type 1 and type 2 diabetes, respectively. EPO exerts antiapoptotic, proliferative, antiinflammatory, and angiogenic effects within the islets. Using β-cell-specific EPO receptor and JAK2 knockout mice, we show that these effects of EPO result from direct biological effects on β cells and that JAK2 is an essential intracellular mediator. Thus, promotion of EPO signaling in β cells may be a novel therapeutic strategy for diabetes prevention and treatment.     

乌司他丁经p38MAPK通路对脓毒症大鼠急性肾损伤影响的研究

目的研究乌司他丁（UTI）经p38MAPK通路对脓毒症大鼠急性肾损伤（AKI）的影响。 方法采用脂多糖（LPS）诱导脓毒症AKI大鼠模型,将32只SD大鼠随机分为4组,空白对照组、脂多糖组（LPS组）、乌司他丁处理组（LPS+UTI组）、p38MAPK阻断剂干预组（LPS+SB组）,采用酶联免疫吸附试验（ELISA）法检测肾组织中肿瘤坏死因子α（TNF-α）和转化生长因子（TGF-β1）的表达,采用蛋白质免疫印迹试验（Western Blotting）检测肾组织中磷酸化p38MAPK蛋白的表达,并在光镜和电镜下观察肾小球及肾小管的变化。 结果与空白对照组相比,LPS组光镜下肾小球充血肿胀,肾球囊扩张,近曲肾小管上皮细胞肿胀明显,细胞核淡染,部分出现核浓缩、破碎甚至溶解现象,肾间质充血、水肿、大量炎性细胞浸润;电镜下肾小球毛细血管内皮细胞窗孔消失或闭塞,基底膜部分断裂消失,足细胞足突广泛融合消失,近曲肾小管上皮细胞质内线粒体排列紊乱,结构模糊,高度肿胀,有空泡样现象;均提示脓毒症肾损伤严重,且肾组织TNF-α、TGF-β1和p38MAPK蛋白的表达明显升高。与LPS组相比,LPS+UTI组肾组织TNF-α、TGF-β1和p38MAPK蛋白的表达均较LPS组下降［TNF-α（pg/ml）：4915.00±267.06 vs 8836.00±739.51;TGF-β1（pg/ml）：257.71±23.88 vs 354.39±29.44;p-p38MAPK/β-actin：0.158±0.022 vs 0.300±0.044,均P＜0.05］,LPS+SB组肾组织中TNF-α、TGF-β1和p38MAPK蛋白的表达较LPS组均下降［TNF-α（pg/ml）：4856.75±167.23 vs 8836.00±739.51;TGF-β1（pg/ml）：249.56±23.42 vs 354.39±29.44;p-p38MAPK/β-actin：0.136±0.017 vs 0.300±0.044,均P＜0.05］,但LPS+UTI组与LPS+SB组差异无统计学意义（P＞0.05）。 结论乌司他丁对脓毒症急性肾损伤有保护作用,且可能是通过抑制TGF-β1/p38MAPK信号转导通路来实现的。     

ADAR2 increases in exercised heart and protects against myocardial infarction and doxorubicin-induced cardiotoxicity

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Role of phosphatidylinositol 3-kinase/AKT as a survival pathway against CYP2E1-dependent toxicity

The objective of this work was to evaluate the possible role of PI3-kinase/AKT as a survival pathway against CYP2E1-dependent toxicity. E47 cells (HepG2 cells transfected with human CYP2E1 cDNA) exposed to 25 microM iron-nitrilotriacetate+5 microM arachidonic acid (AA+Fe) developed higher toxicity than C34 cells (HepG2 cells transfected with empty plasmid). Toxicity was associated with increased oxidative stress and activation of calcium-dependent hydrolases calpain and phospholipase A2. Treatment of E47, but not C34 cells, with arachidonic acid and iron (AA+Fe) led to a decrease in the phosphorylation state of AKT. 2-(4-Morpholinyl)-8-phenyl-1(4H)-benzopyran-4-one hydrochloride (LY294002), a specific inhibitor of PI3-kinase, produced a further decrease of phosphorylated AKT in AA+Fe-treated E47 cells. LY294002 and down-regulation of endogenous AKT with small interference RNAs increased the toxicity of AA+Fe in E47 cells. Toxicity of AA+Fe in rat hepatocytes was also increased by LY294002. LY294002 did not affect phospholipase A2 or calpain activation, CYP2E1 activity, or lipid peroxidation elicited by AA+Fe. alpha-Tocopherol prevented both AA+Fe and AA+Fe+LY294002-induced toxicity and decrease of phosphorylated AKT. LY294002 potentiated AA+Fe-induced loss of mitochondrial membrane potential and ATP, whereas overexpression of constitutively active AKT partially prevented mitochondrial impairment and toxicity. Mitochondrial permeability transition inhibitors prevented both AA+Fe and AA+Fe+LY294002-induced toxicity and decrease of mitochondrial membrane potential. These results suggest that: i) AA+Fe+CYP2E1-induced oxidative stress decreases AKT activation; ii) AKT inactivation induces mitochondrial impairment associated with opening of the permeability transition pore but is not dependent on the activation state of bad, glycogen synthase kinase-3beta, mammalian target of rapamycin, or bcl-xL; and iii) PI3-kinase/AKT may serve as a survival pathway against CYP2E1-dependent toxicity.     

Heat shock protein 25-enriched plasma transfusion preconditions the heart against doxorubicin-induced dilated cardiomyopathy in mice

Extracellular heat shock proteins (eHsps) in the circulation have recently been found to activate both apoptotic and protective signaling in the heart. However, the role of eHsps in doxorubicin (Dox)-induced heart failure has not yet been studied. The objective of the present study was to determine how Dox affects circulating eHsp25 in blood plasma and how eHsp25 affects Dox-induced dilated cardiomyopathy. Wild-type mice [HSF-1(+/+)] were pretreated with 100 μl of heterozygous heat shock factor-1 [HSF-1(+/-)] mouse plasma (which contained 4-fold higher eHsp25 compared with wild-type mice), HSF-1(+/+) plasma, or saline, before treatment with Dox (6 mg/kg). After 4 weeks of this treatment protocol, HSF-1(+/-) plasma-pretreated mice showed increased eHsp25 in plasma and improved cardiac function (percentage of fractional shortening 37.3 ± 2.1 versus 26.4 ± 4.0) and better life span (31 ± 2 versus 22 ± 3 days) compared with the HSF-1(+/+) plasma or saline-pretreated mice. Preincubation of isolated adult cardiomyocytes with HSF-1(+/-) plasma or recombinant human Hsp27 (rhHsp27) significantly reduced Dox-induced activation of nuclear factor-κB and cytokine release and delayed cardiomyocyte death. Moreover, when cardiomyocytes were incubated with fluorescence-tagged rhHsp27, a saturation in binding was observed, suggesting that eHsp25 can bind to surface receptors. Competitive assays with a Toll-like receptor 2 (TLR2) antibody reduced the rhHSP27 binding, indicating that Hsp25 interacts with TLR2. In conclusion, transfusion of Hsp25-enriched blood plasma protected the heart from Dox-induced cardiotoxicity. Hsp25 antagonized Dox binding to the TLR2 receptor on cardiomyocytes.     

Chondroitin sulfate protects SH-SY5Y cells from oxidative stress by inducing heme oxygenase-1 via phosphatidylinositol 3-kinase/Akt

We investigated the mechanism of the neuroprotective properties of chondroitin sulfate (CS), an endogenous perineuronal net glycosaminoglycan, in human neuroblastoma SH-SY5Y cells subjected to oxidative stress. Preincubation with CS for 24 h afforded concentration-dependent protection against H2O2-induced toxicity (50 microM for 24 h) measured as lactic dehydrogenase released to the incubation media; cell death was prevented at the concentrations of 600 and 1000 microM. Cell death caused by a combination of 10 microM rotenone plus 1 microM oligomycin-A (Rot/oligo) was also reduced by CS at concentrations ranging from 0.3 to 100 microM; in this toxicity model, maximum protection was achieved at 3 microM (48%). No significant protection was observed in a cell death model of Ca2+ overload (70 mM K+, for 24 h). H2O2 and Rot/oligo generated reactive oxygen species (ROS) measured as an increase in the fluorescence of dichlorofluorescein diacetate-loaded cells. CS drastically reduced ROS generation induced by both H2O2 (extracellular ROS) and Rot/oligo (intracellular ROS). CS also increased the expression of phosphorylated Akt and heme oxygenase-1 by 2-fold. The protective effects of CS were prevented by chelerythrine, 2-(4-morpholinyl)-8-phenyl-4H-1-benzopyran-4-one (LY294002), cycloheximide, and Sn(IV)-protoporphyrin IX. Taken together, these results show that CS can protect SH-SY5Y cells under oxidative stress conditions by activating protein kinase C, which phosphorylates Akt that, via the phosphatidylinositol 3-kinase/Akt pathway, induces the synthesis of the antioxidant protein heme oxygenase-1.     

Lysophosphatidic acid is a major serum noncytokine survival factor for murine macrophages which acts via the phosphatidylinositol 3-kinase signaling pathway.

Lysophosphatidic acid (LPA) is the smallest and structurally simplest of all the glycerophospholipids. It occurs normally in serum and binds with high affinity to albumin, while retaining its biological activity. The effects of LPA are pleiotropic and range from mitogenesis to stress fiber formation. We show a novel role for LPA: as a macrophage survival factor with potency equivalent to serum. Administration of LPA protects macrophages from apoptosis induced by serum deprivation, and protection is equivalent to that with conventional survival factors such as macrophage colony stimulating factor. The ability of LPA to act as a survival factor is mediated by the lipid kinase phosphatidylinositol 3-kinase (PI3K), since LPA activated both the p85-p110 and p110gamma isoforms of PI3K and macrophage survival was blocked completely by wortmannin or LY294002, two mechanistically dissimilar inhibitors of PI3K. pp70(s6k), a downstream kinase activated by PI3K, also contributes to survival, because inhibitors of pp70(s6k), such as rapamycin, blocked macrophage survival in the presence of LPA. Modified forms of LPA and phospholipids, such as phosphatidylcholine and phosphatidylethanolamine, had no survival effect, thereby showing the specificity of LPA. These results show that LPA acts as a potent macrophage survival factor. Based on striking similarities between our LPA and serum data, we suggest that LPA is a major noncytokine survival factor in serum.     

Dexmedetomidine protects cardiomyocytes against hypoxia/reoxygenation injury via multiple mechanisms

BackgroundMyocardial infarction (MI) is a serious cardiovascular disease associated with myocardial ischemia/reperfusion (I/R) injury. Dexmedetomidine (Dex), an α2‐adrenoceptor agonist, has been reported to protect against I/R injury. We examined the cardioprotective effects of Dex on cardiomyocytes under hypoxia/reoxygenation (H/R) conditions and explored the underlying mechanisms.Materials and methodsA H/R model was established to mimic the MI injury. The CCK‐8 assay was performed to measure cell viability. Cellular apoptosis was measured using the Annexin V fluorescein isothiocyanate (FITC)‐propidium iodide (PI) staining. The levels of interleukin (IL)‐1α and tumor necrosis factor (TNF)‐α, and the activity of lactate dehydrogenase (LDH) were measured using a commercial enzyme‐linked immunosorbent assay (ELISA) kit. Reactive oxygen species (ROS) were measured using the 2''‐7’ dichlorofluorescein diacetate (DCFH‐DA) staining assay. In addition, the levels of malondialdehyde (MDA) and the activity of superoxide dismutase (SOD), catalase (CAT), and caspase‐3 were measured using a commercial kit. siRNA was used to silence Bcl‐2, catalase, or STAT3. Western blotting was used to measure the change in the levels of proteins.ResultsDex improved the cell viability and inhibited the inflammatory response in H9c2 cells exposed to H/R treatment. In addition, Dex inhibited apoptosis and alleviated the endoplasmic reticulum (ER) stress and oxidative stress in H9c2 cells under the H/R treatment. Mechanism investigation showed that Dex inhibited the intrinsic pathway of apoptosis. Moreover, Dex enhanced the activation of the JAK2/STAT3 signaling pathway in H/R‐treated H9c2 cells.ConclusionAltogether, our findings suggested Dex as a promising therapeutic agent for myocardial I/R.     

CHPG通过调控mGluR5表达及JNK信号通路抑制LPS诱导的小胶质细胞激活

目的 探讨激活mGluR5为什么能够抑制激活小胶质细胞诱导的炎症反应. 方法 在正常的和基因敲减mGluR5的小胶质细胞中,用脂多糖(LPS)建立炎症模型,通过Griess实验、酶联免疫吸附试验、免疫印迹法、流式细胞术等方法,探测CHPG对LPS诱导的炎症反应,mGluR5表达及其下游MAPKs信号分子活性的影响. 结果 LPS诱导炎症反应,引起mGluR5表达量下降,下游JNK活性下降,CHPG逆转上述过程(P=0.0003, P=0.005).在mGluR5敲减的细胞中,CHPG作用消失(P=0.4694, P=0.4407). 结论 激活mGluR5抑制炎症反应是通过上调该受体表达量及其下游的JNK信号通路实现的.     

LECT2 protects mice against bacterial sepsis by activating macrophages via the CD209a receptor

Leukocyte cell–derived chemotaxin 2 (LECT2) is a multifunctional cytokine and reduced plasma levels were found in patients with sepsis. However, precise functions and mechanisms of LECT2 remain unclear. The aim of the present study was to determine the role of LECT2 in modulating immune responses using mouse sepsis models. We found that LECT2 treatment improved outcome in mice with bacterial sepsis. Macrophages (MΦ), but not polymorphonuclear neutrophils, mediated the beneficial effect of LECT2 on bacterial sepsis. LECT2 treatment could alter gene expression and enhance phagocytosis and bacterial killing of MΦ in vitro. CD209a was identified to specifically interact with LECT2 and mediate LECT2-induced MΦ activation. CD209a-expressing MΦ was further confirmed to mediate the effect of LECT2 on sepsis in vivo. Our data demonstrate that LECT2 improves protective immunity in bacterial sepsis, possibly as a result of enhanced MΦ functions via the CD209a receptor. The modulation of MΦ functions by LECT2 may serve as a novel potential treatment for sepsis.Sepsis is defined as infection with systemic inflammatory reaction syndrome and can be the result of injury, burn, pancreatitis, surgery, and other disease states (Levy et al., 2003). More than half of sepsis cases are caused by infection with bacteria, among which the most important pathogens include Escherichia coli and Pseudomonas aeruginosa (Annane et al., 2005). Sepsis remains the leading cause of death in critically ill patients worldwide, despite modern advances in critical care. Macrophages (MΦ) are the key component of the innate immune system, forming a bridge between innate and adaptive immunity by producing a myriad of cytokines, and phagocytosing and presenting antigens to the immune system, responses which are severely impaired in septic patients (Hotchkiss and Karl, 2003). Thus, MΦ are a potentially important therapeutic target in sepsis (Anderson et al., 2012).Leukocyte cell–derived chemotaxin 2 (LECT2) is a multifunctional factor originally identified as a neutrophil chemotactic protein (Yamagoe et al., 1996), consisting of 151 amino acids and three intramolecular disulfide bonds. It is produced in the liver and secreted into the blood. LECT2 is involved in many pathological conditions, such as renal amyloidosis (Benson et al., 2008), hepatocarcinogenesis (Ong et al., 2011), and severe liver injury (Saito et al., 2004). Most recently, plasma LECT2 levels were found to be down-regulated in septic patients (Ando et al., 2012), suggesting a relationship between LECT2 and sepsis. However, precise functions and mechanisms of LECT2 in sepsis remain unclear. C-type lectin receptors (CLRs) perform multiple functions in myeloid cells, including MΦ (Kang et al., 2003; Osorio and Reis e Sousa, 2011). CD209, pattern recognition receptors belonging to the CLR superfamily, can not only recognize exogenous carbohydrate ligands to provide innate resistance to microbial infection (Robinson et al., 2006) but also bind to endogenous self-ligands to maintain immune homeostasis (García-Vallejo and van Kooyk, 2009). For example, SIGN-R1(CD209b) in spleen MΦ can capture pneumococcal capsular polysaccharide to activate complement system through an unusual C3 activation pathway (Kang et al., 2006).In this study, we determined that LECT2 treatment improved survival in septic mice via the increased phagocytic ability, bactericidal activity, and beneficial cytokine production of MΦ. These effects were mediated through CD209a. Moreover, CD209a-expressing MΦ mediated the effect of LECT2 on sepsis. Collectively, our data suggest that LECT2 plays a potentially important role in MΦ activation and for the treatment of sepsis.     

Erythropoietin inhibits apoptosis in breast cancer cells via an Akt-dependent pathway without modulating in vivo chemosensitivity

Evidence for erythropoietin signaling has been shown in several nonhematopoietic tissues, including many tumor types. Clinically, recombinant erythropoietin treatment of malignancy-related anemia has yet to be definitively associated with any modulation of chemotherapy or radiotherapy efficacy. Preclinically, recombinant erythropoietin has been shown to increase tumor oxygenation, but the direct effects of recombinant erythropoietin on tumor cells that express erythropoietin receptor are not yet fully characterized. This study examined the effects of exogenous recombinant erythropoietin on rodent mammary adenocarcinoma cells (R3230) in vitro and in vivo, and determined the effects of systemic recombinant erythropoietin on tumor growth delay in Taxol treatment. We showed that systemic recombinant erythropoietin treatment of rats bearing R3230 mammary carcinomas induced an increase in phospho-Akt levels within tumor cells. This was associated with a decrease in the frequency of apoptotic cells in tumors from recombinant erythropoietin-treated animals, but did not noticeably affect tumor growth rate. In vitro studies revealed that not only does recombinant erythropoietin induce Akt phosphorylation, but it also stimulates phosphorylation of p44/42 mitogen-activated protein kinases, Erk1 and Erk2. Activation of erythropoietin-mediated signaling in R3230 cells was associated with dose-dependent inhibition of apoptosis in response to Taxol treatment and serum starvation, an effect that was blocked by the addition of a phosphatidylinositol-3-kinase inhibitor. Despite its cytoprotective effects in vitro, recombinant erythropoietin did not significantly affect tumor growth delay in Taxol treatment. This study shows direct recombinant erythropoietin-mediated activation of specific intracellular signaling pathways in mammary adenocarcinoma cells in vivo and in vitro. Modulation of tumor apoptosis pathways by recombinant erythropoietin may have negative consequences by decreasing the chemosensitivity and radiosensitivity of erythropoietin receptor-positive breast tumors, although it did not have any obvious effects on growth with or without chemotherapy in this model.     

Tanshinone IIA protects against myocardial ischemia reperfusion injury by activating the PI3K/Akt/mTOR signaling pathway

ObjectiveTo determine the mechanism by which Tanshinone IIA (Tan IIA) relieves myocardial ischemia reperfusion injury (MIRI) in rats via the PI3K/Akt/mTOR signaling pathway.MethodsSprague-Dawley (SD) rats received an intravenous injection of Tan IIA and LY294002 and were divided into the sham, control (myocardial ischemia reperfusion), Tan-L (low-dose Tan IIA), Tan-H (high-dose Tan IIA), Tan-L + LY (low-dose Tan IIA + LY294002), Tan-H + LY (high-dose Tan IIA + LY294002) and LY (LY294002) groups. Cardiomyocytes obtained from neonatal rats were treated with hypoxia reoxygenatin, Tan IIA and LY294002 and divided into the blank, control, Tan-L, Tan-H, Tan-L + LY, Tan-H + LY and LY groups. Creatine kinase MB isoenzyme (CK-MB) and lactic dehydrogenase (LDH) levels in serum and cardiomyocytes were measured. Area of necrosis/area at risk (AN/AAR) was determined with double staining of TTC and Evan’s blue; viability and apoptosis of cardiomyocytes with MTT and TUNEL assays; SOD, MDA, H₂O₂, SDH and COX levels in heart mitochondria together with PI3K/Akt/mTOR and eNOS expressions and phosphorylation with Western blotting.ResultsThe Tan-L and Tan-H groups showed a remarkable decrease in AN/AAR, serum CK-MB and LDH, mitochondrial MDA and H₂O₂ levels but an increase in SOD activity, SDH and COX levels compared with the control group. However, compared with the Tan-L and Tan-H groups, the Tan-L + LY, Tan-H + LY and LY groups indicated an inverse tendency of those indicators. As shown by MTT and TUNEL, the control group had more severe cell damage than the blank group. Furthermore, cell damage and apoptosis were less severe in the Tan-L and Tan-H groups than in the control group, while the Tan-L + LY, Tan-H + LY and LY groups showed an opposite tendency when compared with the Tan-L and Tan-H groups. Meanwhile, the Tan-L and Tan-H groups showed significantly higher expression levels of PI3K, p-Akt/Akt, mTOR and p-eNOS/eNOS than the control group, whereas the Tan-L + LY, Tan-H + LY and LY groups had lower expression levels than the Tan-L and Tan-H groups.ConclusionOur study provided evidence that Tan IIA could activate the PI3K/Akt/mTOR signaling pathway to relieve MIRI in rats.     

促红细胞生成素促进内皮祖细胞增殖依赖于PI3K/Akt信号通路

背景：促红细胞生成素能促进组织损伤部位血管生成,与其促进内皮祖细胞增殖、分化密切相关,但促红细胞生成素促进内皮祖细胞增殖、分化的机制尚不清楚。 目的：观察促红细胞生成素对小鼠骨髓来源内皮祖细胞功能活性的影响,并初步阐明其信号机制。 方法：密度梯度离心法分离获取小鼠骨髓内皮祖细胞,鉴定后传代培养,以 PI3K 特异性抑制剂 LY294002作干预处理,实验细胞分为EGM-2组、促红细胞生成素处理组（培养液中促红细胞生成素浓度分别为1,5,10 U/mL）、促红细胞生成素＋LY组（培养液中分别含有10 U/mL促红细胞生成素及10 mmol/L LY294002）、LY组（培养液中含10 mmol/L LY294002）、二甲基亚砜组（培养液中含1 mL/L二甲基亚砜）,分别采用CCK8试剂盒、流式细胞法检测细胞增殖和凋亡,采用ELISA法检测细胞裂解液内皮型一氧化氮合酶、血管内皮生长因子含量,Western blot法测定细胞裂解液中Akt及p-Akt表达。 结果与结论：促红细胞生成素能显著促进内皮祖细胞增殖,并随培养基中促红细胞生成素含量增加而呈现量效关系,而促红细胞生成素的促增殖作用可被 LY294002完全抑制。促红细胞生成素处理组细胞凋亡率明显低于促红细胞生成素＋LY组。LY组、促红细胞生成素＋LY组细胞裂解液中内皮型一氧化氮合酶、血管内皮生长因子含量显著低于促红细胞生成素处理各组。各组 Akt 表达无明显差异,而促红细胞生成素＋LY 组 p-Akt表达显著低于促红细胞生成素各组。上述结果提示,促红细胞生成素能显著促进体外培养的内皮祖细胞的增殖、降低内皮祖细胞的凋亡率,其作用依赖于PI3K/Akt信号通路。