Spatiotemporal Variation and Driving Forces Analysis of Eco-System Service Values: A Case Study of Sichuan Province, China.

Sichuan Province is an important ecological barrier in the upper reaches of the Yangtze River. Therefore, it is critical to investigate the temporal and spatial changes, as well as the driving factors, of ecosystem service values (ESVs) in Sichuan Province. This paper used land use data from 2000, 2005, 2010, 2015, and 2020 to quantify the spatiotemporal changes in the ESVs in Sichuan Province. Correlation coefficients and bivariate spatial autocorrelation methods were used to analyze the trade-offs and synergies of ESVs in the city (autonomous prefecture) and grid scales. At the same time, we used a Geographical Detector model (GDM) to explore the synergies between nine factors and ESVs. The results revealed that: (1) In Sichuan Province, the ESVs increased by 0.77% from 729.26 × 109 CNY in 2000 to 741.69 × 109 CNY in 2020 (unit: CNY = Chinese Yuan). Furthermore, ecosystem services had a dynamic degree of 0.13%. Among them, the ESVs of forestland were the highest, accounting for about 60.59% of the total value. Among the individual ecosystem services, only food production, environmental purification, and soil conservation decreased in value, while the values of other ecosystem services increased. (2) The ESVs increased with elevation, showing a spatial distribution pattern of first rising and then decreasing. The high-value areas of ESVs per unit area were primarily distributed in the forestland of the transition area between the basin and plateau; The low-value areas were distributed in the northwest, or the urban areas with frequent human activities in the Sichuan Basin. (3) The tradeoffs and synergies between multi-scale ecosystems showed that ecosystem services were synergies-dominated. As the scale of research increased, the tradeoffs between ecosystems gradually transformed into synergies. (4) The main driving factors for the spatial differentiation of ESVs in Sichuan Province were average annual precipitation, average annual temperature, and gross domestic product (GDP); the interaction between normalized difference vegetation index (NDVI) and GDP had the strongest driving effect on ESVs, generally up to 30%. As a result, the distribution of ESVs in Sichuan Province was influenced by both the natural environment and the social economy. The present study not only identified the temporal and spatial variation characteristics and driving factors of ESVs in Sichuan Province, but also provided a reference for the establishment of land use planning and ecological environmental protection mechanisms in this region.

Study on Spatiotemporal Variation Pattern of Vegetation Coverage on Qinghai-Tibet Plateau and the Analysis of Its Climate Driving Factors.

As one of the most sensitive areas to global environmental change, especially global climate change, the Qinghai-Tibet Plateau is an ideal area for studying global climate change and ecosystems. There are few studies on the analysis of the vegetation's driving factors on the Qinghai-Tibet Plateau based on large-scale and high-resolution data due to the incompetence of satellite sensors. In order to study the long-term vegetation spatiotemporal pattern and its driving factors, this study used the enhanced spatial and temporal adaptive reflectance fusion model (ESTARFM) to improve the spatial resolution of the GIMMS NDVI3g (8 km) data of the Qinghai-Tibet Plateau in 1990 and 1995 based on the MODIS NDVI (500 m) data. The research on the spatiotemporal pattern and driving factors of vegetation on the Qinghai-Tibet Plateau from 1990 to 2015 was carried out afterward, with combined data including topographic factors, annual average temperature, and annual precipitation. The results showed that there was a strong correlation between the actual MODIS NDVI image and the fused GIMMS NDVI3g image, which means that the accuracy of the fused GIMMS NDVI3g image is reliable and can provide basic data for the accurate evaluation of the spatial and temporal patterns of vegetation on the Qinghai-Tibet Plateau. From 1990 to 2015, the overall vegetation coverage of the Qinghai-Tibet Plateau showed a degrading trend at a rate of -0.41%, and the degradation trend of vegetation coverage was the weakest when the slope was ≥25°. Due to the influence of the policy of returning farmland to forests, the overall degradation trend has gradually weakened. The significant changes in vegetation in 2010 can be attributed to the difference in the spatial distribution of climatic factors such as temperature and precipitation. The area with reduced vegetation in the west was larger than the area with increased vegetation in the east. The effects of temperature and precipitation on the distribution, direction, and degradation level of vegetation coverage were varied by the areal differentiation in different zones.

Knockdown of activated Cdc42-associated kinase inhibits human extravillous trophoblast migration and invasion and decreases protein expression of pho-Akt and matrix metalloproteinase.

Introduction: The sufficient invasion and migration of human extravillous trophoblast (EVTs) cells are crucial for placentation. Inadequate invasion of trophoblasts may correlate with the development of preeclampsia. Many studies have suggested that activated Cdc42-associated kinase (ACK1) is associated with tumor metastasis and invasion. This study investigated the ACK1 expression and its function in trophoblasts during placental development.Methods: ACK1 expression in human placentas was determined through immunofluorescence. We investigated the migration/invasion of the immortalized human first-trimester EVT cell line HTR8/SVneo. Hypoxia-reoxygenation (H/R) conditions were applied to mimic preeclampsia model in vitro. Lentiviral vector-based short-hairpin RNA directed against the sequence of ACK1 (ACK1 shRNA) was used to knock down ACK1 expression in HTR8/SVneo cells. Cell apoptosis and proliferation were determined through flow cytometry and cell counting Kit-8 (CCK-8) assays, respectively. The expression of matrix metalloproteinase (MMP) 2/9 and tissue inhibitors of metalloproteinase (TIMP) 1/2 was measured by western blotting.Results: ACK1 localized within trophoblasts of human placental villi, decidual cells in the maternal decidua. ACK1 levels in preeclampsia (PE) placentas were significantly lower than those in controls. ACK1 shRNA significantly inhibited HTR8/SVneo cells migration and invasion but did not affect their apoptosis and proliferation. ACK1 knockdown decreased MMP2/9 and increased TIMP1/2 expression, as well as downregulated the phosphorylation of AKt (p-Akt). In addition, ACK1 and MMP2/9 were downregulated following treatment with LY294002, whereas ACK1 shRNA had no effect on phosphorylation of PI3K(p-PI3K). After exposed in H/R condition, ACK1 expression, MMP2/9 protein, and p-Akt were also significantly decreased.Discussion and conclusions: ACK1 expression is lowered in preeclamptic placentas and promotes trophoblast cell invasion, migration. H/R conditions decrease ACK1 expression and appear to decouple the positive relationship between ACK1 expression and Akt activation.

Hypoxia-induced Downregulation of SRC-3 Suppresses Trophoblastic Invasion and Migration Through Inhibition of the AKT/mTOR Pathway: Implications for the Pathogenesis of Preeclampsia.

Preeclampsia (PE) is characterized by poor placentation, consequent on aberrant extravillous trophoblast (EVT) cell function during placental development. The SRC family of proteins is important during pregnancy, especially SRC-3, which regulates placental morphogenesis and embryo survival. Although SRC-3 expression in mouse trophoblast giant cells has been documented, its role in the functional regulation of extravillous trophoblasts and the development of PE remains unknown. This study found that SRC-3 expression was significantly lower in placentas from PE pregnancies as compared to uncomplicated pregnancies. Additionally, both CoCl2-mimicked hypoxia and suppression of endogenous SRC-3 expression by lentivirus short hairpin RNA attenuated the migration and invasion abilities of HTR-8/SVneo cells. Moreover, we demonstrated that SRC-3 physically interacts with AKT to regulate the migration and invasion of HTR-8 cells, via the AKT/mTOR pathway. We also found that the inhibition of HTR-8 cell migration and invasion by CoCl2-mimicked hypoxia was through the SRC-3/AKT/mTOR axis. Our findings indicate that, in early gestation, accumulation of HIF-1α inhibits the expression of SRC-3, which impairs extravillous trophoblastic invasion and migration by directly interacting with AKT. This potentially leads to insufficient uterine spiral artery remodeling and placental hypoperfusion, and thus the development of PE.

Interleukin-27 Inhibits Trophoblast Cell Invasion and Migration by Affecting the Epithelial-Mesenchymal Transition in Preeclampsia.

Preeclampsia (PE) is a pregnancy-specific disorder representing a major cause of maternal and perinatal morbidity and mortality. Invasive and migratory phenotypes are acquired by trophoblasts through the process of epithelial-mesenchymal transition (EMT). Studies have shown that trophoblast EMT events are dysregulated in PE and play an important role in its development. Dysregulation of interleukin (IL)-27 and IL-27R (T-cell cytokine receptor (TCCR)/WSX -1) is relevant to PE. In this study, our results demonstrated that IL-27 did not significantly affect the proliferation and apoptosis of HTR -8/SVneo trophoblast cells, while it did significantly inhibit trophoblast invasion and migration. The expression of EMT-related proteins in HTR-8/SVneo cells and extravillous explants was detected after treatment with IL-27. Expression of epithelial markers was increased, and mesenchymal marker expression was reduced. Furthermore, we found that IL-27 could induce significant phosphorylation of Signal Transducer and Activator of Transcription 1 (STAT1) and Signal Transducer and Activator of Transcription 3 (STAT3) in a time-dependent manner in HTR-8/SVneo cells. Selective inhibitors of STAT1 (STAT1 siRNA) and STAT3 (STAT3 siRNA) were used to determine whether both STAT1 and STAT3 are required for IL-27-mediated inhibition of EMT. STAT1 inhibition in IL-27-treated cells attenuated the IL-27 effect, while the inhibition of STAT3 activation had no effect on the development of the epithelial phenotype. These results demonstrate that IL-27 may inhibit trophoblast cell migration and invasion by affecting the EMT process through an STAT1-dominant pathway in PE.

SRC-3 Plays a Critical Role in Human Umbilical Vein Endothelial Cells by Regulating the PI3K/Akt/mTOR Pathway in Preeclampsia.

Preeclampsia (PE) is currently thought to be characterized by oxidative stress which may lead to endothelial dysfunction. The normal function of vascular endothelium is essential to vascular homeostasis. Previous studies have shown that steroid receptor coactivator 3 (SRC-3) interacts with estrogen receptors (ERs) which are involved in the vasoprotective effects of estrogen and is also associated with cell migration, invasion, and inflammation; however, its role in PE remains unclear. The main purpose of this study is to identify the role of SRC-3 in the function of human umbilical vein endothelial cells (HUVECs) during the development of PE. Our study demonstrated that the expression of SRC-3 was significantly decreased in PE placentas compared to normal placentas. Additionally, lentivirus short hairpin RNA against SRC-3 and hypoxia/reoxygenation treatments attenuated migration and tube formation abilities and enhanced HUVEC apoptosis. Furthermore, we detected possible downstream in the PI3K/Akt/mammalian target of rapamycin (mTOR) signal pathway activity, which is involved in SRC-3-mediated HUVEC function. Our data suggest that oxidative stress plays a crucial role in controlling SRC-3 expression, which influences the migration and tube formation abilities of endothelial cells through the PI3K/Akt/mTOR signaling pathways. This action may then result in PE pathogenesis.