[Effects of Apelin-13 on barrier injury of human umbilical vein endothelial cells induced by LPS].

Objective: To investigate the effects of Apelin-13 on barrier function injury of human umbilical vein endothelial cells (HUVECs) induced by LPS. Methods: The HUVECs cultured in vitro were divided into 4 groups: Control group, LPS group, Apelin-13+LPS group, Apelin-13 group. HUVECs were treated by 5 µg/ml LPS for 24 h to replicate the model with endothelial barrier impaired. Apelin-13 at the concentration of 1 µmol/L was given 30 min before LPS treatment. The cell viabillity of HUVECs was measured by CCK-8 assay. Protein expressions of VE-cadherin and F-actin were measured by Western blot and immunofluorescence. Nuclear factor κB p65(NF-κB p65) was detected by immunofluorescence. Results: Compared with the control group, the cell viabillity of HUVECs and protein expression of VE-cadherin were decreased by LPS, but the protein expression of F-actin and activation of NF-κB p65 were increased by LPS. These effects were attenuated by Apelin-13 administration. Conclusion: Apelin-13 ameliorates LPS-induced barrier function injury of HUVECs, which may be related to the inhibition of inflammation.

[Effect of autophagy inhibitor chloroquine on acute alcoholinduced liver disease].

OBJECTIVES: To investigate the role of autophagy inhibitor chloroquine (CQ) in acute ethanol-induced liver injury and its mechenism. METHODS: Twenty-one C57BL/6 male mice were randomly divided into three groups:control group, ethanol group, CQ + ethanol group (n=7). Mice in ethanol group were administered 33% (v/v) ethanol at a dose of 4.5 g/kg body weight. Ethanol-induced liver steatosis in each group was detected by hematoxylin and eosin staining. Hepatic lipid accumulation was detected by staining with Oil red O. Hepatic tissue triglyceride (TG) levels, serum aspartate aminotransferase(AST) and alanine aminotransferase(ALT) were determined by biochemical assays. Protein expression of microtubule-associated protein 1 light chain 3(LC3) and nuclear factorκB p65(NF-κB p65) were measured by Western blot and immunofluorescence. Pro-inflammatory factors tumor necrosis factor-α(TNF-α)、interleukin 6(IL-6) were detected by ELISA. RESULTS: Compared with control group, ethanol induced liver injury proved by accumulation of hepatic lipids, TG levels, AST and ALT activities were significantly increased by ethanol, protein expression of LC3-Ⅱ was also markedly increased by ethanol. Compared with ethanol group, addition of CQ increased furtherthe level of LC3-Ⅱexpression, and TG amount, serum AST and ALT activities, and the expression of NF-κB p65, TNF-αand IL-6. CONCLUSIONS: Acute ethanol-intake could induce liver steatosis and inflammation, and autophagy inhibitor CQ exacerbatedethanol-induced liver injury, suggested that autophagy might be protective effect in acute ethanol-induced liver disease.

Endoplasmic reticulum stress: relevance and therapeutics in central nervous system diseases.

Endoplasmic reticulum (ER) stress plays an important role in a range of neurological disorders, such as neurodegenation diseases, cerebral ischemia, spinal cord injury, sclerosis, and diabetic neuropathy. Protein misfolding and accumulation in the ER lumen initiate unfolded protein response in energy-starved neurons which are relevant to toxic effects. In neurological disorders, such as Alzheimer's disease, Parkinson's disease, and Huntington's disease, ER dysfunction is well recognized, but the mechanisms remain unclear. In stroke and ischemia, spinal cord injury, and amyotrophic lateral sclerosis, chronic activation of ER stress is considered as main pathogeny which causes neuronal disorders. By targeting components of these ER signaling responses, to explore clinical treatment strategies or new drugs in CNS neurological diseases might become possible and valuable in the future.

The Apelin-APJ axis is an endogenous counterinjury mechanism in experimental acute lung injury.

BACKGROUND: Although the mechanisms and pathways mediating ARDS have been studied extensively, less attention has been given to the mechanisms and pathways that counteract injury responses. This study found that the apelin-APJ pathway is an endogenous counterinjury mechanism that protects against ARDS. METHODS: Using a rat model of oleic acid (OA)-induced ARDS, the effects of ARDS on apelin and APJ receptor expressions and on APJ receptor binding capacity were examined. The protective effect of activating the apelin-APJ pathway against OA- or lipopolysaccharide (LPS)-induced ARDS was evaluated. RESULTS: ARDS was coupled to upregulations of the apelin and APJ receptor. Rats with OA-induced ARDS had higher lung tissue levels of apelin proprotein and APJ receptor expressions; elevated plasma, BAL fluid (BALF), and lung tissue levels of apelin-36 and apelin-12/13; and an increased apelin-APJ receptor binding capacity. Upregulation of the apelin-APJ system has important pathophysiologic function. Stimulation of the apelin-APJ signaling using receptor agonist apelin-13 alleviated, whereas inhibition of the apelin-APJ signaling using receptor antagonist [Ala]-apelin-13 exacerbated, OA-induced lung pathologies, extravascular lung water accumulation, capillary-alveolar leakage, and hypoxemia. The APJ receptor agonist inhibited, and the APJ receptor antagonist augmented, OA-induced lung tissue and BALF levels of tumor necrosis factor-α and monocyte chemoattractant protein-1, and plasma and lung tissue levels of malondialdehyde. Postinjury treatment with apelin-13 alleviated lung inflammation and injury and improved oxygenation in OA- and LPS-induced lung injury. CONCLUSIONS: The apelin-APJ signaling pathway is an endogenous anti-injury and organ-protective mechanism that is activated during ARDS to counteract the injury response and to prevent uncontrolled lung injury.

[Effect of autophagy inhibitor chloroquine on the proliferation of PASMCs induced by hypoxia].

OBJECTIVE: To investigate the role of autophagy inhibitor chloroquine (CQ) in the proliferation of pulmonary arterial smooth muscle cells (PASMCs) in hypoxia conditions. METHODS: The following groups in this study were set up: control group, hypoxia group, 50 micromol/L CQ + hypoxia group, 50 micromol/L CQ group. The viability of PASMCs in every group was detected by MTT assay. Autophagic vacuoles in the cells were observed by MDC staining. Protein expression of microtubule associated protein light chain 3 (LC3) was measured by Western blot. Migration of PASMCs was detected by wound healing assay. RESULTS: Compared with control group, no effect on the viability of PASMCs was observed treated by CQ alone. In 1% hypoxia group, cell viability increased significantly compared with that in control group. The number of autophagic vacuoles and the rate of cell migration and also protein expression of LC3-II were also markedly increased. Compared with hypoxia group, addition of CQ increased the number of autophagic vacuoles and the levels of LC3-II protein, but decreased the proliferation and migration of PASMCs. CONCLUSION: Hypoxia could activates autophagy and contributes to proliferation and migration of PASMCs, and autophagy inhibitor CQ could decrease the effect of hypoxia on PASMCs through inhibiting autophagy process.

[Changes of apelin and its receptor in lung tissue of rats with pulmonary hypertension induced by monocrotaline].

OBJECTIVE: To observe the change of apelin and its receptor (APJ) in the lung tissue of rats with pulmonary hypertension induced by monocrotaline and to explore its significance. METHODS: Twenty-five male SD rats were randomly divided into control group (n = 10) and monocrotaline group (n = 15). On the twenty-first day after the rats were intraperitoneally injected 60 mg/kg monocrotaline for monocrotaline group or equal volume vehicle for control group, the mean pulmonary artery pressure was measured by right heart catheterization. Histopathological study of lung tissue was done with hematoxylin-eosin (HE) and Masson's trichrome staining. The concentration of apelin in the plasma was measured by radioimmunoassay. The expressions of apelin/APJ proteins and genes in lung tissue were measured respectively by Western blot and reverse transcription polymerase chain reaction (RT-PCR). RESULTS: The mean pulmonary arterial pressure, right ventricular hypertrophy, pulmonary vascular remodeling index, content of apelin protein in lung tissue of monocrotaline group were higher than those in control group. APJ protein and gene expression in monocrotaline group were significantly lower than those in control group (P < 0.01, P < 0.05), but apelin gene expression in the lung tissue between the two groups had no significant difference. CONCLUSION: Endogenous apelin/APJ dysfunction may play an important role in the development of pulmonary hypertension induced by monocrotaline.

Regulation of autophagy and ubiquitinated protein accumulation by bFGF promotes functional recovery and neural protection in a rat model of spinal cord injury.

The role of autophagy in the recovery of spinal cord injury remains controversial; in particular, the mechanism of autophagy regulated degradation of ubiquitinated proteins has not been discussed to date. In this study, we investigated the protective role of basic fibroblast growth factor (bFGF) both in vivo and in vitro and demonstrated that excessive autophagy and ubiquitinated protein accumulation is involved in the rat model of trauma. bFGF administration improved recovery and increased the survival of neurons in spinal cord lesions in the rat model. The protective effect of bFGF is related to the inhibition of autophagic protein LC3II levels; bFGF treatment also enhances clearance of ubiquitinated proteins by p62, which also increases the survival of neuronal PC-12 cells. The activation of the downstream signals of the PI3K/Akt/mTOR pathway by bFGF treatment was detected both in vivo and in vitro. Combination therapy including the autophagy activator rapamycin partially abolished the protective effect of bFGF. The present study illustrates that the role of bFGF in SCI recovery is related to the inhibition of excessive autophagy and enhancement of ubiquitinated protein clearance via the activation of PI3K/Akt/mTOR signaling. Overall, our study suggests a new trend for bFGF drug development for central nervous system injuries and sheds light on protein signaling involved in bFGF action.

[Changes of endoplasmic reticulum stress-induced apoptosis in pulmonary tissue of rats with hypoxic pulmonary hypertension].

OBJECTIVE: To investigate the changes of endoplasmic reticulum stress-induced apoptosis in pulmonary tissue of rats with hypoxic pulmonary hypertension. METHODS: Twenty two male SD rats were randomly divided into control group and 4-week hypoxia-hypercapnia group (n=11). The mean pulmonary arterial pressure (mPAP) and the mean carotid arterial pressure (mCAP) were monitored, and the weight ratio of right ventricle (RV) to left ventricle plus septum (LV + S) were measured. The rattish pathological model were assessed by mPAP, mCAP, RV/(LV+ S), vessel wall area/total area (WA/TA), vessel cavity area/total area (CA/TA) and media thickness of pulmonary arteriole (PAMT). The pulmonary apoptotic cells were detected by Hoechst staining. RT-PCR was used to study the genetic expression of caspasel2, glucose regulated protein 78 (GRP78) and GRP94 in pulmonary tissue. The expression of GRP94 and GRP78 proteins in pulmonary tissue were determined by using immunohistochemistry. RESULTS: (1) (The mPAP, RV/(LV + S), WA/TA and PAMT were respectively higher by 50.5%, 37.3%, 72.5% and 137% in hypoxic group than those in control group, while CA/TA was lower by 41.9% (all P < 0.01). There was not significant difference of mCAP between the two groups. (2) Hoechst staining showed that the pulmonary apoptotic cells in hypoxic group outnumbered markedly than those in control group, and the apoptotic cells were mainly in pulmonary tissue, while they were rare in pulmonary vascular smooth muscle cell. (3) Compared with control group, the expression of pulmonary caspasel2, GRP78 and GRP94 mRNA in hypoxic group were higher by 144%, 137% and 80.7% (all P < 0.05), respectively. (4) The expression of pulmonary GRP78 and GRP94 proteins were up-regulated in hypoxic group, and these proteins mainly localized in pulmonary vascular endothelial cell. CONCLUSION: The endoplasmic reticulum stress-induced apoptosis may be one of the mechanism of hypoxic pulmonary hypertension and pulmonary vascular wall remodeling.

[Inhibition of Beclin 1 enhances apoptosis by H2O2 in glioma U251 cells].

Oxidative stress could induce apoptosis and autophagy process simultaneously, but the role of autophagy is still not clear. Beclin 1, a key gene regulating the preautophagosome formation, is involved in the injury induced by oxidative stress. To observe the role of autophagy in H2O2-induced injury of U251 cells, the recombinant plasmid Psilencer3.1-siRNA-Beclin 1 was transfected into U251 cells by eukaryotic cell transfection technique. Plasmid vector and cell culture medium were used as negative and control groups respectively. The cells were collected 24 h later, and the cell total protein was extracted to detect Beclin 1, Bcl-2 and Bax protein expressions by Western blot. After the Beclin 1-siRNA cells were treated with 1 mmol/L H2O2, the autophagic vacuoles in the cells were stained with monodansylcadaverine (MDC), and the cell apoptotic ratio was determined with PI/Annexin V-FITC staining by flow cytometry analysis. The results showed that the synthetic siRNA decreased the expression of Beclin 1 protein significantly, but had no obvious effect on the levels of Bcl-2 and Bax protein expressions. Compared with those in the control group, the autophagic vacuoles, the level of LC3-II protein expression and the percentage of apoptotic cells increased (P < 0.05) in 1 mmol/L H2O2 group. In Beclin 1-siRNA + H2O2 group, autophagic vacuoles and the levels of LC3-II protein expression decreased obviously, the percentage of apoptotic cells increased significantly compared with that in 1 mmol/L H2O2 group (P < 0.05). H2O2 and autophagy inhibitor 3-methyladenine (3-MA) combination also increased the percentage of apoptotic cells obviously (P < 0.05). These results revealed that the transfection of Psilencer3.1-siRNA-Beclin 1 effectively inhibited the expression of Beclin 1 protein expression, degraded the autophagy level and increased the apoptotic rate in U251 cells under oxidative stress, which was coincident with the effect of autophagy inhibitor 3-MA. This study suggests that autophagy is a cell protective role in oxidative stress process, and the inhibition of autophagy may enhance apoptosis.

[The time order of autophagy and apoptosis process in the oxidative injury in glioma U251 cells].

OBJECTIVE: To investigate the time order of autophagy and apoptosis in human U251 cells injury after H2O2 treatment. METHODS: 4 groups in this study were set up, normal control group, 1 mmol/L H2O2 (6 h,12 h, 24 h) group. The viability of U251 cells treated with H2O2 was measured by MTT assay. Cell apoptotic ratio was determined by flow cytometry analysis. Autophagic vacuoles were stained with monodansylcadaverine. The protein level of Beclin 1 and cytosolic cyt c were assayed by using Western blot. RESULTS: Compared with the control group, cell viability decreased significantly under 1 mmol/L H2O2 treatment in time-dependent way. Autophagic vacuoles and the expression of autophagic protein Beclin 1 increased at 6 h, but cell apoptotic ratio and cytosolic cyt c protein did not change obviously, cell apoptotic ratio and cytosolic cyt c protein level increased at 12 h and 24 h (P < 0.05). CONCLUSION: Oxidative stress induced autophagy and apoptosis in U251 glioma cells, and autophagy eventuated ahead of apoptosis.

Effects of plant polyphenols on ovarian follicular reserve in aging rats.

The pool of ovarian primordial follicles is established during embryonic development or at birth. During the development from primordial to primary, secondary, and antral follicles, only a small portion of follicles can mature and successfully ovulate; the others are destined to degenerate through apoptotic or atretic loss. As aging advances, females ultimately enter the cessation phase of the estrous cycle and are no longer capable of fertilization. The presumption is that if we can slow down the process of folliculogenesis or decrease follicle loss, females may have a larger ovarian follicular reserve and a longer reproductive lifespan. In our study, rats underwent intragastric administration with tea polyphenols, quercetin (meletin), genistein, or resveratrol, once a day for 4 months (from age 12 to 15 months), to test whether they have positive effects on follicular reserve or ovarian functions. The results showed that rats treated with tea polyphenols (27.8 +/- 3.2) and quercetin (36.5 +/- 4.1) had a comparable number of healthy follicles to those of controls (26.9 +/- 3.8), although significantly fewer atretic follicles were observed in the tea polyphenol group (43.4 +/- 5.9 vs 79.7 +/- 7.5; p < 0.001). Remarkably, both genistein- and resveratrol-treated rats had more healthy follicles (respectively, 42.8 +/- 3.9, p < 0.05; and 51.9 +/- 6.4, p < 0.001) and fewer atretic follicles (respectively, 58.4 +/- 8.0, p < 0.05; and 51.0 +/- 6.2, p < 0.01) than controls. These results indicate that genistein and resveratrol can increase the ovarian follicular reserve and prolong the ovarian lifespan in rats, and their positive effects may be not only due to their intervention in the transition from primordial to primary follicle, but also due to the inhibiting effect on follicular atresia.

Effects of genistein on ovarian follicular development and ovarian life span in rats.

Recently, studies reported that neonatal genistein treatment inhibited breakdown of oocyte nests and increased oocyte survival, resulting in multi-oocyte survival in adult mice. However, whether the inhibition effect in ovarian follicular development exists also in other stages during ovarian development (e.g. adult or climacteric) is unknown. So far, few studies have investigated the effect of genistein in adult or pre-menopausal ovarian follicular development and follicular reserves. We investigated ovarian follicular development in 4-month and 15-month-old rats after 4 weeks and 4 months treatment with genistein in a dose of 160 mg/kg d. Genistein-treated rats obtained a higher percentage of primordial follicles by 4 months of age and a greater number of surviving follicles at 15 months of age compared to a control group (P<0.05). In addition, vaginal cytology showed that age-dependent cessation of regular estrus was delayed for 2 months in the genistein-treated group than control group. These results suggest that genistein alters rat ovarian follicular development and increases the number of surviving follicles, which may prolong ovarian reproductive life.