Mutations in LRRK2 are thus far the most frequent known cause of autosomal dominant and idiopathic Parkinson’s disease (PD) with prevalent mutations being found within the GTPase (R1441C/G) and kinase (G2019S) domains. Previous in vitro studies have revealed that R1441C and G2019S mutations are associated with increased kinase activity. To better understand LRRK2-linked PD pathogenesis in vivo, we have generated transgenic C. elegans overexpressing human LRRK2 wild type, R1441C and G2019S in dopaminergic (DA) neurons. Overexpression of these LRRK2 proteins causes age-dependent DA neurodegeneration, behavioral deficits, and locomotor dysfunction that are accompanied by a reduction of dopamine levels in vivo. In comparison, R1441C and G2019S mutants cause more severe phenotypes than the wild type protein. Interestingly, treatment with exogenous dopamine rescues the LRRK2-induced behavioral and locomotor phenotypes. In contrast, expression of the GTP binding defective mutant, K1347A, or knockout of the C. elegans LRRK2 homolog, LRK-1, prevents the LRRK2-induced neurodegeneration and behavioral abnormalities. Hence, our transgenic LRRK2 C. elegans models recapitulate key features of PD including progressive neurodegeneration, impairment of dopamine-dependent behavior and locomotor function, and reduction in dopamine levels. Furthermore, our findings provide strong support for the critical role of GTPase/kinase activity in LRRK2-linked pathologies. These invertebrate models will be useful for studying pathogenesis of PD and for development of potential therapeutics for the disease.
The intelligent vehicle is a complicated nonlinear system, and the design of a path tracking controller is one of the key technologies in intelligent vehicle research. This paper mainly designs a lateral control dynamic model of the intelligent vehicle, which is used for lateral tracking control. Firstly, the vehicle dynamics model (i.e., transfer function) is established according to the vehicle parameters. Secondly, according to the vehicle steering control system and the CARMA (Controlled Auto-Regression and Moving-Average) model, a second-order control system model is built. Using forgetting factor recursive least square estimation (FFRLS), the system parameters are identified. Finally, a neural network PID (Proportion Integral Derivative) controller is established for lateral path tracking control based on the vehicle model and the steering system model. Experimental simulation results show that the proposed model and algorithm have the high real-time and robustness in path tracing control. This provides a certain theoretical basis for intelligent vehicle autonomous navigation tracking control, and lays the foundation for the vertical and lateral coupling control.
To investigate the role of miRNA in controlling human embryonic stem (hES) cell differentiation toward the endothelial lineage and chick embryonic blood vessel formation, undifferentiated hES cells were first cultured on Matrigelcoated flasks and in endothelial cell growth medium-2 (EGM-2) to initiate endothelial cell (EC) differentiation.
Objective-Smooth muscle cell (SMC) migration and proliferation play an essential role in neointimal formation after vascular injury. In this study, we intended to investigate whether the X-box-binding protein 1 (XBP1) was involved in these processes. Approach and Results-In vivo studies on femoral artery injury models revealed that vascular injury triggered an immediate upregulation of XBP1 expression and splicing in vascular SMCs and that XBP1 deficiency in SMCs significantly abrogated neointimal formation in the injured vessels. In vitro studies indicated that platelet-derived growth factor-BB triggered XBP1 splicing in SMCs via the interaction between platelet-derived growth factor receptor β and the inositolrequiring enzyme 1α. The spliced XBP1 (XBP1s) increased SMC migration via PI3K/Akt activation and proliferation via downregulating calponin h1 (CNN1). XBP1s directed the transcription of mir-1274B that targeted CNN1 mRNA degradation. Proteomic analysis of culture media revealed that XBP1s decreased transforming growth factor (TGF)-β family proteins secretion via transcriptional suppression. TGF-β3 but not TGF-β1 or TGF-β2 attenuated XBP1s-induced CNN1 decrease and SMC proliferation. Conclusions-This study demonstrates for the first time that XBP1 is crucial for SMC proliferation via modulating the platelet-derived growth factor/TGF-β pathways, leading to neointimal formation. under stress conditions. [21][22][23] Under ER stress conditions, XBP1 mRNA undergoes unconventional splicing through an ER-resident kinase that possesses ribonuclease activity, the inositol-requiring enzyme 1 α (IRE1α). 24 Our recent studies and reports from other groups showed that physiological stimuli such as vascular endothelial cell growth factor could trigger XBP1 splicing in an ER stress response-independent manner. [25][26][27][28] In endothelial cells (ECs), XBP1 splicing plays diverse roles, including cell proliferation, 26 autophagy response, 29 and apoptosis. 30 In SMCs, bone morphogenetic protein-2 was reported to activate XBP1 splicing, 31 but the exact role of XBP1 in SMCs still remains unclear. In this study, we demonstrated that XBP1 splicing is crucial in PDGF-BB-induced SMC proliferation and contributes to neointima formation after vascular injury. Materials and MethodsMaterials and Methods are available in the online-only Data Supplement. Results Vascular Injury Increased XBP1 Expression and SplicingIn response to vascular injury, vascular SMCs will be activated undergoing migration, proliferation, and apoptosis. 32 To test whether XBP1 was involved in SMC activation, femoral artery injury model was introduced into the right side of C57Bl/6 mice. The injured vessels were harvested at day 1, and day 3 post surgery, whereas the left uninjured vessels were collected as control. Double immunofluorescence staining with anti-α SMC actin and antispliced XBP1 (XBP1s) or unspliced XBP1 (XBP1u) antibodies were performed on the cryo-sections. As shown in Figure 1A, low levels of XBP1s and XBP1u were detected in the uninjure...
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