C.-P. Chen

EGb761 Provides a Protective Effect against Aβ1-42 Oligomer-Induced Cell Damage and Blood-Brain Barrier Disruption in an In Vitro bEnd.3 Endothelial Model

Alzheimer’s disease (AD) is the most common form of senile dementia which is characterized by abnormal amyloid beta (Aβ) accumulation and deposition in brain parenchyma and cerebral capillaries, and leads to blood-brain barrier (BBB) disruption. Despite great progress in understanding the etiology of AD, the underlying pathogenic mechanism of BBB damage is still unclear, and no effective treatment has been devised. The standard Ginkgo biloba extract EGb761 has been widely used as a potential cognitive enhancer for the treatment of AD. However, the cellular mechanism underlying the effect remain to be clarified. In this study, we employed an immortalized endothelial cell line (bEnd.3) and incubation of Aβ1–42 oligomer, to mimic a monolayer BBB model under conditions found in the AD brain. We investigated the effect of EGb761 on BBB and found that Aβ1–42 oligomer-induced cell injury, apoptosis, and generation of intracellular reactive oxygen species (ROS), were attenuated by treatment with EGb761. Moreover, treatment of the cells with EGb761 decreased BBB permeability and increased tight junction scaffold protein levels including ZO-1, Claudin-5 and Occludin. We also found that the Aβ1–42 oligomer-induced upregulation of the receptor for advanced glycation end-products (RAGE), which mediates Aβ cytotoxicity and plays an essential role in AD progression, was significantly decreased by treatment with EGb761. To our knowledge, we provide the first direct in vitro evidence of an effect of EGb761 on the brain endothelium exposed to Aβ1–42 oligomer, and on the expression of tight junction (TJ) scaffold proteins and RAGE. Our results provide a new insight into a possible mechanism of action of EGb761. This study provides a rational basis for the therapeutic application of EGb761 in the treatment of AD.

Human placental multipotent mesenchymal stromal cells modulate trophoblast migration via Rap1 activation

INTRODUCTIONnLittle is known about the interaction between human placental multipotent mesenchymal stromal cell (hPMSC) and trophoblast. We hypothesize that hPMSCs produce hepatocyte growth factor (HGF) which may interact with trophoblasts and regulate their migration during placentation.nnnMETHODSnhPMSCs were isolated from term placentas and conditioned medium was collected after 2 days of culture in hypoxic (<1% O2) or control (20% O2) conditions. Selective agonist and inhibitor or siRNA for protein kinase A (PKA) or Rap1 were combined with Rap1-GTP pull down assays, flow cytometry, integrin β1 activation assays and adhesion and migration studies to investigate HGF signaling effects in trophoblasts. The hPMSC abundance and HGF level in preeclamptic placentas were compared with gestational age-matched controls.nnnRESULTSnHGF was expressed by hPMSCs and was decreased in hypoxia. HGF induced cAMP production and Rap1 activation in trophoblasts, which in turn activated integrin β1. The HGF and PKA activator 6-Bnz-cAMP induced Rap1 activation with increased trophoblast adhesion and migration. The alterations were inhibited by PKA inhibitor H89 or Rap1 siRNA. HGF and cAMP expression were reduced in preeclamptic placentas. hPMSC number was decreased in preeclamptic placenta compared to controls (0.68 ± 0.1% vs. 1.32 ± 0.5%; P = 0.026). hPMSC conditioned medium enhanced trophoblast migration which was inhibited by c-Met blocking antibody, but migration was reduced by conditioned medium from hPMSC cultured in hypoxia.nnnCONCLUSIONSnhPMSCs secrete HGF and increase trophoblast cAMP production. The cAMP effector PKA modulates adhesion and migration of trophoblast via signaling to Rap1 and integrin β1.

Heparan sulfate proteoglycans in the basement membranes of the human placenta and decidua.

Basement membranes lie at the epithelial-mesenchymal interface of most tissues. These thin layers of highly specialized extracellular matrix vary in composition in different tissues and also over the course of tissue morphogenesis. Heparan sulfate proteoglycans, which were originally identified in basement membranes, interact with extracellular matrix proteins, growth factors and cell receptors, and influence cellular signaling. Members of this family in the human placenta and decidua that act principally in linking to collagen IV and laminin networks include perlecan, agrin, and collagen XVIII, each of which have characteristic locations. Perlecan is widely expressed in trophoblasts, the villous and endothelial basement membranes, villous stroma, and decidua, whereas collagen XVIII is not expressed in trophoblasts. Agrin expression is quite limited, occurring only in the decidua and villous stroma. Pathological conditions may alter the expression and structure of the covalently attached glycosaminoglycan chains of these molecules in the placenta. Such changes may result in remodeling of the basement membrane during placental development with consequent adverse effects, as seen for example in gestational diabetes and other diseases or experimental models.

IFPA Meeting 2011 workshop report III: Placental immunology; epigenetic and microRNA-dependent gene regulation; comparative placentation; trophoblast differentiation; stem cells

Workshops are an important part of the IFPA annual meeting as they allow for discussion of specialised topics. At IFPA meeting 2011 there were twelve themed workshops, five of which are summarized in this report. These workshops related to various aspects of placental biology: 1) immunology; 2) epigenetics; 3) comparative placentation; 4) trophoblast differentiation; 5) stem cells.

EGb761 protects against Aβ1-42 oligomer-induced cell damage via endoplasmic reticulum stress activation andHsp70 protein expression increase in SH-SY5Y cells

Studies have shown that misfolded proteins and endoplasmic reticulum (ER) stress play pivotal roles in the progression of Alzheimers disease (AD). It has also been reported that ER stress is considered to be a common mediator of apoptosis in neurodegenerative disorders like AD. However, the precise mechanisms leading to neuronal cell death caused by ER stress in AD remain unclear. Hsp70, the major inducible form of the heat shock protein family, functions at the level of chaperone-mediated protein folding. Enhanced expression of Hsp70 suppresses the neurotoxicity caused by protein misfolding. EGb761, an accepted traditional Chinese medicine used to treat AD, was used here to examine the molecular mechanism underlying its protective effect on ER stress and Hsp70. Our study shows that pretreatment with EGb761 overcomes the neurotoxicity of the Aβ1-42 oligomer by increasing Hsp70, Grp78, IRE1α and pAkt expression in a dose-dependent manner and significantly decreases cell apoptosis-related protein expression. Our findings suggest that the neuroprotective effect of EGb761 is related to ER stress activation and increased Hsp70 expression, and subsequent activation of Akt. However, the effect of EGb761 on these processes is not direct.

IFPA Meeting 2012 Workshop Report III: Trophoblast deportation, gestational trophoblastic disease, placental insufficiency and fetal growth restriction, trophoblast over-invasion and accreta-related pathologies, placental thrombosis and fibrinolysis

Workshops are an important part of the IFPA annual meeting as they allow for discussion of specialized topics. At IFPA meeting 2012 there were twelve themed workshops, five of which are summarized in this report. These workshops related to various aspects of placental biology but collectively covered areas of clinical research and pregnancy disorders: 1) trophoblast deportation; 2) gestational trophoblastic disease; 3) placental insufficiency and fetal growth restriction; 4) trophoblast overinvasion and accreta-related pathologies; 5) placental thrombosis and fibrinolysis.

Chinese herbal medicine for miscarriage affects decidual micro-environment and fetal growth

INTRODUCTIONnIntrauterine growth restriction complicates 5-10% of pregnancies. This study aims to test the hypothesis that Chinese herbal formula, JLFC01, affects pregnancy and fetal development by modulating the pro-inflammatory decidual micro-environment.nnnMETHODSnHuman decidua from gestational age-matched elective terminations or incomplete/missed abortion was immunostained using anti-CD68xa0+xa0anti-CD86 or anti-CD163 antibodies. qRT-PCR and Luminex assay measured the effects of JLFC01 on IL-1β- or TNF-α-induced cytokine expression in first trimester decidual cells and on an established spontaneous abortion/intrauterine growth restriction (SA/IUGR)-prone mouse placentae. The effect of JLFC01 on human endometrial endothelial cell angiogenesis was evaluated by average area, length and numbers of branching points of tube formation. Food intake, litter size, fetal weight, placental weight and resorption rate were recorded in SA/IUGR-prone mouse treated with JLFC01. qRT-PCR, Western blot and immunohistochemistry assessed the expression of mouse placental IGF-I and IGF-IR.nnnRESULTSnIn spontaneous abortion, numbers of decidual macrophages expressing CD86 and CD163 are increased and decreased, respectively. JLFC01 reduces IL-1β- or TNF-α-induced GM-CSF, M-CSF, C-C motif ligand 2 (CCL2), interferon-γ-inducible protein-10 (IP-10), CCL5 and IL-8 production in first trimester decidual cells. JLFC01 suppresses the activity of IL-1β- or TNF-α-treated first trimester decidual cells in enhancing macrophage-inhibited angiogenesis. In SA/IUGR-prone mice, JLFC01 increases maternal food intake, litter size, fetal and placental weight, and reduces fetal resorption rate. JLFC01 induces IGF-I and IGF-IR expression and inhibits M-CSF, CCL2, CCL5, CCL11, CCL3 and G-CSF expression in the placentae.nnnDISCUSSIONnJLFC01 improves gestation by inhibiting decidual inflammation, enhancing angiogenesis and promoting fetal growth.