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| − | <html> | + | <html><head><meta http-equiv="Content-Type" content="text/html; charset=UTF-8"> |
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| | <TABLE borderColor=#00ff99 height="100%" width="100%" border=0 style="table-layout:fixed"> | | <TABLE borderColor=#00ff99 height="100%" width="100%" border=0 style="table-layout:fixed"> |
| | <TR height="100%"> | | <TR height="100%"> |
| − | <TD width="27%" bgColor=#EEE8AA style="vertical-align:top"> | + | <TD width="27%" bgColor=#E6E8FA style="vertical-align:top"> |
| | </br> | | </br> |
| | <li style="line-height:250%;margin-left:10%"><a href="https://2015.igem.org/Team:NJU-China" style="font-weight:bold;font-family:幼圆;font-size:25px;color:black">Home</a></li> | | <li style="line-height:250%;margin-left:10%"><a href="https://2015.igem.org/Team:NJU-China" style="font-weight:bold;font-family:幼圆;font-size:25px;color:black">Home</a></li> |
| | <li style="line-height:250%;margin-left:10%"><a href="https://2015.igem.org/NJU-China-background.html" style="font-weight:bold;font-family:幼圆;font-size:25px;color:black">Background</a></li> | | <li style="line-height:250%;margin-left:10%"><a href="https://2015.igem.org/NJU-China-background.html" style="font-weight:bold;font-family:幼圆;font-size:25px;color:black">Background</a></li> |
| | + | <div style="line-height:250%;margin-left:10%" id="main1" onClick="document.all.child0.style.display=(document.all.child0.style.display =='none')?'':'none'" ><a href="#" style="font-weight:bold;font-family:幼圆;font-size:25px;color:black">Project</a></div> |
| | + | <div id="child0" style="display:none"> |
| | + | <ul> |
| | + | <li style="line-height:250%;margin-left:10%"><a href="https://2015.igem.org/Team:NJU-China/Design" style="font-weight:bold;font-family:幼圆;color:black">design</a></li> |
| | + | <li style="line-height:250%;margin-left:10%"><a href="https://2015.igem.org/NJU-China-project/result.html" style="font-weight:bold;font-family:幼圆;color:black">results</a></li> |
| | + | <li style="line-height:250%;margin-left:10%"><a href="https://2015.igem.org/NJU-China-project/conclusion.html" style="font-weight:bold;font-family:幼圆;color:black">conclusion</a></li> |
| | + | <li style="line-height:250%;margin-left:10%"><a href="https://2015.igem.org/NJU-China-project/future work.html" style="font-weight:bold;font-family:幼圆;color:black">future work</a></li> |
| | + | </ul> |
| | + | </div> |
| | <div style="line-height:250%;margin-left:10%" id="main1" onClick="document.all.child1.style.display=(document.all.child1.style.display =='none')?'':'none'" ><a href="#" style="font-weight:bold;font-family:幼圆;font-size:25px;color:black">Model</a></div> | | <div style="line-height:250%;margin-left:10%" id="main1" onClick="document.all.child1.style.display=(document.all.child1.style.display =='none')?'':'none'" ><a href="#" style="font-weight:bold;font-family:幼圆;font-size:25px;color:black">Model</a></div> |
| | <div id="child1" style="display:none"> | | <div id="child1" style="display:none"> |
| | <ul> | | <ul> |
| − | <li style="line-height:250%;margin-left:10%"><a href="https://2015.igem.org/NJU-China-model.html#deliverymodel" style="font-weight:bold;font-family:幼圆;color:black">Delivery model</a></li> | + | <li style="line-height:250%;margin-left:10%"><a href="https://2015.igem.org/NJU-China-model.html" style="font-weight:bold;font-family:幼圆;color:black">Delivery Module</a></li> |
| − | <li style="line-height:250%;margin-left:10%"><a href="#" style="font-weight:bold;font-family:幼圆;color:black">RNAi model</a></li> | + | <li style="line-height:250%;margin-left:10%"><a href="https://2015.igem.org/Team:NJU-China/RNAi" style="font-weight:bold;font-family:幼圆;color:black">RNAi Module</a></li> |
| | + | <li style="line-height:250%;margin-left:10%"><a href="https://2015.igem.org/Team:NJU-China/signaling" style="font-weight:bold;font-family:幼圆;color:black">Signaling Module</a></li> |
| | </ul> | | </ul> |
| | </div> | | </div> |
| − | <li style="line-height:250%;margin-left:10%"><a href="https://2015.igem.org/NJU-China-human-practice.html" style="font-weight:bold;font-family:幼圆;font-size:25px;color:black">Human Practice</a></li> | + | <li style="line-height:250%;margin-left:10%"><a href="https://2015.igem.org/Team:NJU-China/Practices" style="font-weight:bold;font-family:幼圆;font-size:25px;color:black">Human Practice</a></li> |
| | <li style="line-height:250%;margin-left:10%"><a href="https://2015.igem.org/NJU-China-parts.html" style="font-weight:bold;font-family:幼圆;font-size:25px;color:black">Parts</a></li> | | <li style="line-height:250%;margin-left:10%"><a href="https://2015.igem.org/NJU-China-parts.html" style="font-weight:bold;font-family:幼圆;font-size:25px;color:black">Parts</a></li> |
| | <li style="line-height:250%;margin-left:10%"><a href="https://2015.igem.org/NJU-China-team.html" style="font-weight:bold;font-family:幼圆;font-size:25px;color:black">Team</a></li> | | <li style="line-height:250%;margin-left:10%"><a href="https://2015.igem.org/NJU-China-team.html" style="font-weight:bold;font-family:幼圆;font-size:25px;color:black">Team</a></li> |
| | <li style="line-height:250%;margin-left:10%"><a href="https://2015.igem.org/NJU-China-attribution.html" style="font-weight:bold;font-family:幼圆;font-size:25px;color:black">Attribution</a></li> | | <li style="line-height:250%;margin-left:10%"><a href="https://2015.igem.org/NJU-China-attribution.html" style="font-weight:bold;font-family:幼圆;font-size:25px;color:black">Attribution</a></li> |
| − | <li style="line-height:250%;margin-left:10%"><a href="https://2015.igem.org/NJU-China-colaboration.html" style="font-weight:bold;font-family:幼圆;font-size:25px;color:black">Colaborations</a></li> | + | <li style="line-height:250%;margin-left:10%"><a href="https://2015.igem.org/Team:NJU-China/Collaborations" style="font-weight:bold;font-family:幼圆;font-size:25px;color:black">Colaborations</a></li> |
| | <li style="line-height:250%;margin-left:10%"><a href="https://2015.igem.org/NJU-China-safty.html" style="font-weight:bold;font-family:幼圆;font-size:25px;color:black">Safety</a></li> | | <li style="line-height:250%;margin-left:10%"><a href="https://2015.igem.org/NJU-China-safty.html" style="font-weight:bold;font-family:幼圆;font-size:25px;color:black">Safety</a></li> |
| | <div style="line-height:250%;margin-left:10%" id="main2" onClick="document.all.child2.style.display=(document.all.child2.style.display =='none')?'':'none'" > <a href="#" style="font-weight:bold;font-family:幼圆;font-size:25px;color:black">Notebook </div> | | <div style="line-height:250%;margin-left:10%" id="main2" onClick="document.all.child2.style.display=(document.all.child2.style.display =='none')?'':'none'" > <a href="#" style="font-weight:bold;font-family:幼圆;font-size:25px;color:black">Notebook </div> |
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| | </ul> | | </ul> |
| | </div> | | </div> |
| − | | + | <li style="line-height:250%;margin-left:10%"><a href="https://2015.igem.org/NJU-China-acknowledgement.html#notebook" style="font-weight:bold;font-family:幼圆;font-size:20px;color:black">Acknowledgement</a></li> |
| | | | |
| | </TD> | | </TD> |
| | <TD width="73%" bgColor=#FFFFFF style="vertical-align:top;padding-left:80px;padding-right:80px;padding-top:50px;padding-bottom:50px;word-wrap:break-word;"> | | <TD width="73%" bgColor=#FFFFFF style="vertical-align:top;padding-left:80px;padding-right:80px;padding-top:50px;padding-bottom:50px;word-wrap:break-word;"> |
| − | <h1> 1 Delivery module </h1> <br>
| + | <h1> Modeling overview </h1> |
| − | | + | |
| − | <h2> 1.1 Introduction </h2> <br><br>
| + | |
| − |
| + | |
| − | Pharmacokinetics is the quantitative study of drug absorption,
| + | |
| − | | + | |
| − | distribution and metabolism in the body. Pharmacokinetic data are indispensable for
| + | |
| − | | + | |
| − | phase I clinical trials to evaluate the tissue distribution and safety of drugs. To
| + | |
| − | | + | |
| − | construct a strategy for developing efficient and safe in vivo RNAi therapy systems,
| + | |
| − | | + | |
| − | pharmacokinetics at whole body, organ, cellular and sub-cellular levels need to be
| + | |
| − | | + | |
| − | considered [1]. <br><br>
| + | |
| − | | + | |
| − | In our laboratory study (GFP experiment), we obtained a qualitative
| + | |
| − | | + | |
| − | description of in vivo drug distribution after systematic administration. A
| + | |
| − | | + | |
| − | computational and compartmental model was built to provide mechanistic insights into a
| + | |
| − | | + | |
| − | quantitative explanation of the experimental results. <br><br>
| + | |
| − | | + | |
| − | <B> Three primary aspects were counted in this pharmacokinetic model: <br>
| + | |
| − | i) theoretically predicting the effect of RVG modification of the targeting ability of
| + | |
| − | | + | |
| − | exosomes,<br>
| + | |
| − | ii) approximating time-series exosome (siRNA) concentration data for use in modeling
| + | |
| − | | + | |
| − | RNAi kinetics in target tissue and subsequently calculating the effective dose, and
| + | |
| − | | + | |
| − | <br>
| + | |
| − | iii) determining what portion of the delivery system could be improved based on
| + | |
| − | | + | |
| − | simulation data. </B> <br><br>
| + | |
| − | | + | |
| − | <h2> 1.2 Model methods </h2> <br><br>
| + | |
| − | The process of drug delivery in humans and mice is quite
| + | |
| − | | + | |
| − | complex. Physiologically speaking, drug delivery after administration can be simplified
| + | |
| − | | + | |
| − | into two separate phases: <br>
| + | |
| − | <B> i) circulation from a central compartment (blood) to a
| + | |
| − | | + | |
| − | peripheral compartment (body tissues), and</B> <br>
| + | |
| − | <B> ii) uptake and trafficking at cellular and sub-cellular
| + | |
| − | | + | |
| − | levels in target tissues.</B> <br>
| + | |
| − | Although physiologically based pharmacokinetic (PBPK) models
| + | |
| − | | + | |
| − | have been widely used in clinical trials, few described the cellular uptake behavior
| + | |
| − | | + | |
| − | because most of the available drugs, at present, are chemically synthesized and have
| + | |
| − | | + | |
| − | different biological properties compared with exosomes. Exosomes differ from
| + | |
| − | | + | |
| − | conventional chemical drugs because of their distinct biological characteristics as
| + | |
| − | | + | |
| − | microvesicles [2]. <B>Thus, we would like to modify the current PBPK model and add
| + | |
| − | | + | |
| − | details regarding cellular uptake behavior based on the biological nature of
| + | |
| − | | + | |
| − | exosomes.</B><br><br>
| + | |
| − | | + | |
| − | <h3> 1.2.1 Modeling multi-compartmental transport</h3> <br>
| + | |
| − | In our laboratory work, we measured the relative level of GFP
| + | |
| − | | + | |
| − | in the brain, liver, lung and spleen after injecting anti-GFP siRNA into mouse.
| + | |
| − | | + | |
| − | <B>Thus, we examined separate compartments for the brain, liver, lung and spleen.</B>
| + | |
| − | | + | |
| − | Other tissues were merged into one compartment. Each peripheral compartment had blood
| + | |
| − | | + | |
| − | exchange with the central blood circulation, during which a certain percentage of
| + | |
| − | | + | |
| − | exosomes were captured into the extracellular matrix of endothelial cells in different
| + | |
| − | | + | |
| − | tissues.<br><br>
| + | |
| − | | + | |
| − | | + | |
| − | <img src="https://2015.igem.org/File:NJU-China-Model_Figure1.jpg"> <!--插入第一幅图--> <br><br>
| + | |
| − | | + | |
| − | | + | |
| − | Figure 1. Schematic diagram of the arrangement of different tissues in the
| + | |
| − | | + | |
| − | pharmacokinetic model. The blood, along with exosomes, circulates from the central
| + | |
| − | | + | |
| − | compartment to five peripheral compartments.<br><br>
| + | |
| − | | + | |
| − | As membrane vesicles, exosomes may rapidly shift from
| + | |
| − | | + | |
| − | associating with other complexes and disassociating into a free format during blood
| + | |
| − | | + | |
| − | circulation. Moreover, the ultimate fate of exosomes, similar to other microvesicles,
| + | |
| − | | + | |
| − | is degradation by lysosomes after internalization via a common process discussed later.
| + | |
| − | | + | |
| − | Research has shown that microvesicles, containing miRNAs or siRNAs, are stable in serum
| + | |
| − | | + | |
| − | and play significant biological roles in cell communication [3]. Furthermore, the
| + | |
| − | | + | |
| − | elimination of exosomes occurs primarily in specific tissues rather than in blood
| + | |
| − | | + | |
| − | circulation, albeit that the half-life of exosomes in blood circulation is much shorter
| + | |
| − | | + | |
| − | [4].<B> These two findings suggest that the elimination rate of exosomes in blood
| + | |
| − | | + | |
| − | circulation is negligible compared with that in target tissues and does not need to be
| + | |
| − | | + | |
| − | considered in this portion of the pharmacokinetic model.</B><br><br>
| + | |
| − | | + | |
| − | Using standard mass action kinetics, the equations below
| + | |
| − | | + | |
| − | describe the change in the concentration (mass) of free exosomes over time in blood and
| + | |
| − | | + | |
| − | target tissues. Here, <I>kblooddis</I> and <I>kbloodbind</I> represents the association
| + | |
| − | | + | |
| − | and disassociation, respectively, of exosomes to other complexes in the blood
| + | |
| − | | + | |
| − | circulation.<br><br>
| + | |
| − | | + | |
| − | <img src="https://static.igem.org/mediawiki/2015/6/62/NJU-China-Equation_delivery_1.jpg">
| + | |
| − | | + | |
| − | <!-- delivery公式1 -->
| + | |
| − | | + | |
| − | <br><br>
| + | |
| − | | + | |
| − | Notably, not all exosomes are effective or completely
| + | |
| − | | + | |
| − | absorbed by tissues. Therefore, <I>partitiontissue</I> is included to describe the
| + | |
| − | | + | |
| − | effective fraction of the dose. Additionally, <I>Et</I> represents the quantity of
| + | |
| − | | + | |
| − | exosomes captured by the extracellular matrix of cells in tissues, but does not
| + | |
| − | | + | |
| − | represent the final quantity of exosomes in tissues, which will be discussed in the
| + | |
| − | | + | |
| − | next portion of the model. <I>Qtissue</I> and <I>Qc</I> represents the velocity of
| + | |
| − | | + | |
| − | blood flowing in peripheral and central compartments, respectively.<br><br>
| + | |
| − | | + | |
| − | <img src="https://static.igem.org/mediawiki/2015/7/7c/NJU-China-Equation-
| + | |
| − | | + | |
| − | Equation_delivery_2.jpg">
| + | |
| − | <!-- 这里要插第三张图，是第二个出现的一条公式 -->
| + | |
| − | | + | |
| − | <br><br>
| + | |
| − | | + | |
| − | This work is supported by model of IGEM Slovenia 2012, IGEM
| + | |
| − | | + | |
| − | NJU-China 2013 and other literatures [5,6].<br><br>
| + | |
| − | | + | |
| − | | + | |
| − | <h3>1.2.2 Modeling cellular uptake and intracellular trafficking</h3> <br><br>
| + | |
| − | | + | |
| − | Extracellular vesicles can be internalized by cells via a
| + | |
| − | | + | |
| − | variety of pathways, namely, phagocytosis, clathrin- and caveolin-mediated endocytosis
| + | |
| − | | + | |
| − | and macropinocytosis [7]. We assume that receptor-mediated endocytosis is the major
| + | |
| − | | + | |
| − | pathway of primary exosome internalization.<br> <br>
| + | |
| − | | + | |
| − | The cellular uptake pathway is summarized in Figure_2.
| + | |
| − | | + | |
| − | Exosomes bind to the membranes of target cells after being captured by the
| + | |
| − | | + | |
| − | extracellular matrix and then internalized through endocytosis. The receptor-ligand
| + | |
| − | | + | |
| − | interaction may facilitate this process. After internalization, the RISC complex may
| + | |
| − | | + | |
| − | escape from endosomes, and endosomes may be ultimately eliminated by lysosomes.
| + | |
| − | | + | |
| − | Although other pathways such as transcytosis and exocytosis following endocytosis may
| + | |
| − | | + | |
| − | occur, we did not take them into account for simplification.<br><br>
| + | |
| − | | + | |
| − |
| + | |
| − | ——————这里放Figure.2，就是红色的点点exosome那个图——————<br><br>
| + | |
| − | | + | |
| − | Figure 2. Pathways that participate in exosomes uptake by target cells. Exosomes are
| + | |
| − | | + | |
| − | transported from the extracellular matrix to the cell surface and undergo intracellular
| + | |
| − | | + | |
| − | trafficking after internalization. The RISC complex in exosomes is released, and
| + | |
| − | | + | |
| − | exosomes are ultimately degraded.<br><br>
| + | |
| − | | + | |
| − | We used several equations to describe the above pathway. RVG
| + | |
| − | | + | |
| − | modification helps exosomes bind acetylcholine receptors specifically expressed in
| + | |
| − | | + | |
| − | neuronal cells. <B>Exosomes internalization is much easier provided that more exosomes
| + | |
| − | | + | |
| − | bind target cells.</B> The binding process is modeled using mass action kinetics.
| + | |
| − | | + | |
| − | <I>AR</I> denotes the number of acetylcholine receptors on target cells, and <I>km</I>
| + | |
| − | | + | |
| − | represents the specific binding constant. Non-receptor-ligand interaction--mediated
| + | |
| − | | + | |
| − | binding is summarized using <I>kbindtissue</I>.<br><br>
| + | |
| − | | + | |
| − | <img src="https://static.igem.org/mediawiki/2015/9/93/NJU-China-Equation-
| + | |
| − | | + | |
| − | Equation_delivery_3.jpg">
| + | |
| − | <!-- 这里要插第三个公式 -->
| + | |
| − | <br><br>
| + | |
| − | | + | |
| − | The internalization and elimination of exosomes are
| + | |
| − | | + | |
| − | formulated below using the parameters <I>kinttissue</I> and <I>kelimttissue</I>,
| + | |
| − | | + | |
| − | respectively. Note that different tissues have different internalization and
| + | |
| − | | + | |
| − | elimination rates.<br> <br>
| + | |
| − | | + | |
| − | <img src="https://static.igem.org/mediawiki/2015/9/93/NJU-China-Equation-
| + | |
| − | | + | |
| − | Equation_delivery_3.jpg">
| + | |
| − | <!-- 这里要插第四个公式 -->
| + | |
| − | <br><br>
| + | |
| − | | + | |
| − | The quantity of the endosomal RISC complex and escape
| + | |
| − | | + | |
| − | behavior is modeled using the following equation. The concentration of siRNA in
| + | |
| − | | + | |
| − | exosomes is determined by real-time RT-PCR in the literature [8] and represented by
| + | |
| − | | + | |
| − | <I>kc</I>. <I>kescendvec</I> represents the escape rate of the RISC complex from
| + | |
| − | | + | |
| − | exosomes (endosomes) to the cytosol.<br> <br>
| + | |
| − | | + | |
| − | ——————这里放第五个出现的公式的图，该图在word里面的figure.2下面的下面的下面———
| + | |
| − | | + | |
| − | —<br>
| + | |
| − | | + | |
| − | This part of work is based on literature [5].<br> <br>
| + | |
| − | | + | |
| − | | + | |
| − | <h2> 1.3 Parameter finding and adjustment </h2> <br><br>
| + | |
| − | The most challenging part of modeling is finding and
| + | |
| − | | + | |
| − | adjusting parameters. After reviewing the literature, we unfortunately found that few
| + | |
| − | | + | |
| − | of the parameters have been measured or reported directly. The original paper written
| + | |
| − | | + | |
| − | by Bartlett and Davis uses synthetic polyplexes as carriers to deliver siRNA [5]. The
| + | |
| − | | + | |
| − | stability and targeting ability of synthetic polyplexes diverge considerably from
| + | |
| − | | + | |
| − | exosomes due to their different biochemical nature. Using all the parameters in the
| + | |
| − | | + | |
| − | original paper without adjustment would not be appropriate because of different
| + | |
| − | | + | |
| − | biochemical natures and consequences of these delivery systems. <br><br>
| + | |
| − | | + | |
| − | Parameter adjustment is not unusual in modeling biological
| + | |
| − | | + | |
| − | processes. This endeavor is a somewhat uncertain endeavor and lacks specific
| + | |
| − | | + | |
| − | procedures. In an iterative process, each set of parameters must be run through the
| + | |
| − | | + | |
| − | model and modified to bring the output of the model into better and better agreement
| + | |
| − | | + | |
| − | with observed experiment and literature results [9]. <B>Following this doctrine, we ran
| + | |
| − | | + | |
| − | our simulation and attempted to fit the results to the experimental and literature
| + | |
| − | | + | |
| − | data. </B><br><br>
| + | |
| − | | + | |
| − | <B>You can access the description of model variables and
| + | |
| − | | + | |
| − | parameters here.</B> The determination of the parameters is also described in the list.
| + | |
| − | | + | |
| − | When one parameter was reported in the literature, we cited the literature directly;
| + | |
| − | | + | |
| − | when the parameter was not accessible but could be estimated and fitted to the
| + | |
| − | | + | |
| − | literature or experimental results, we used the terms “estimated from literature and
| + | |
| − | | + | |
| − | experimental results”.<br><br>
| + | |
| − | | + | |
| − | <h2>1.4 Results</h2> <br><br>
| + | |
| − | We simulated the pharmacokinetic model and obtained initial
| + | |
| − | | + | |
| − | results. Unfortunately, the results showed that the model was not accurate.
| + | |
| − | | + | |
| − | <B>Distinguishing the effects of RVG modification on the tissue distribution of
| + | |
| − | | + | |
| − | exosomes was difficult, as shown in the figure below.</B><br><br>
| + | |
| − | | + | |
| − | ————这里放Figure.3的图，就是那个Control-Without RVG modification——<br><br>
| + | |
| − | | + | |
| − | Figure 3. Effect of RVG modification on the tissue distribution of exosomes. A: Without
| + | |
| − | | + | |
| − | RVG modification; B: With RVG modification. The initial results are simulated with
| + | |
| − | | + | |
| − | partitionbrain set at 1×10-1.<br><br>
| + | |
| − | | + | |
| − | Why did we obtain unrealistic simulation results? The answer
| + | |
| − | | + | |
| − | simply lies in the parameter set we chose. <B>After performing parameter sensitivity
| + | |
| − | | + | |
| − | analysis, we were surprised to find that exosome bindings to the neuronal cell surface
| + | |
| − | | + | |
| − | does not determine the internalization rate.</B> In contrast, <I>paritionbrain</I> is
| + | |
| − | | + | |
| − | more sensitive, indicating that the rate limiting step for exosome internalization is
| + | |
| − | | + | |
| − | its effective dose fraction to targeted cells.<br> <br>
| + | |
| − | | + | |
| − | We next carefully investigated the presence of BBB and the
| + | |
| − | | + | |
| − | effect of RGV modification on paritionbrain. The blood brain barrier is formed by
| + | |
| − | | + | |
| − | endothelial cells at the level of cerebral capillaries [10]. The cerebral endothelial
| + | |
| − | | + | |
| − | cells may form complex tight junctions that interfere with permeability. The binding of
| + | |
| − | | + | |
| − | RVG to acetylcholine receptors, which are present in high density at the neuromuscular
| + | |
| − | | + | |
| − | junction, would provide a mechanism whereby exosomes could be locally concentrated at
| + | |
| − | | + | |
| − | sites in proximity to peripheral nerves, facilitating subsequent uptake and transfer to
| + | |
| − | | + | |
| − | the central nervous system [11]. <B>The local concentrating of exosomes at proximal
| + | |
| − | | + | |
| − | sites may significantly increase the effective dose fraction available to targeted
| + | |
| − | | + | |
| − | cells, resulting in a greater number of exosomes passing through the BBB and captured
| + | |
| − | | + | |
| − | by the extracellular matrix of target cells.</B> To our knowledge, this mechanism is
| + | |
| − | | + | |
| − | why exosomes may pass through the BBB much more easily after RVG modification. <B>Thus,
| + | |
| − | | + | |
| − | we hypothesized that <I>partitionbrain</I> may also be influenced by RVG
| + | |
| − | | + | |
| − | modification.</B><br><br>
| + | |
| − | | + | |
| − | With <I>partitionbrain</I> increased by 6-fold, we finally
| + | |
| − | | + | |
| − | obtained optimized simulation results. The biological meaning of this parameter
| + | |
| − | | + | |
| − | adjustment is that RVG modification helps exosomes bind acetyl-choline receptors, not
| + | |
| − | | + | |
| − | only facilitating internalization into target cells but also increasing the ability of
| + | |
| − | | + | |
| − | exosomes to pass though the BBB by at least 6-fold.<br><br>
| + | |
| − | | + | |
| − | | + | |
| − | ——这里放Figure.4的那三张连着的图——————<br><br>
| + | |
| − | | + | |
| − | | + | |
| − | Figure 4. Effect of RVG modification on the tissue
| + | |
| − | | + | |
| − | distribution of exosomes. The results are simulated with <I>partitionbrain</I>
| + | |
| − | | + | |
| − | increased by 6-fold. A-B: Control study of the time course of the tissue-distribution
| + | |
| − | | + | |
| − | of exosomes without RVG modification. C-D: Case study of the time course of the
| + | |
| − | | + | |
| − | tissue-distribution of exosomes with RVG modification and MOR-siRNA as cargo. E: In
| + | |
| − | | + | |
| − | situ simulation of the tissue-distribution of exosomes.<br><br>
| + | |
| − | | + | |
| − | We now better understand our delivery device using
| + | |
| − | | + | |
| − | computational simulation data. The half-life of exosomes in blood is short, which is
| + | |
| − | | + | |
| − | consistent with findings with the literature [12]. The tissue distribution pattern of
| + | |
| − | | + | |
| − | exosomes with or without RVG modifications is also consistent with findings in the
| + | |
| − | | + | |
| − | literature [13] and our GFP experiment. <br><br>
| + | |
| − | | + | |
| − | Furthermore, the simulation data shows that a small portion
| + | |
| − | | + | |
| − | of exosomes may also pass into non-targeted tissues due to circulation. We could
| + | |
| − | | + | |
| − | improve the targeting precision by further modifying the exosomes.<br><br>
| + | |
| − | | + | |
| − | | + | |
| − | <h2>1.5 Conclusion and Remarks</h2> <br><br>
| + | |
| − | | + | |
| − | <B>In this module, we created a pharmacokinetic model to
| + | |
| − | | + | |
| − | simulate the time-dependent tissue distribution of exosomes at whole organ and cellular
| + | |
| − | | + | |
| − | levels. We theoretically tested the effect of RVG modification on the capability of
| + | |
| − | | + | |
| − | exosomes to pass through the BBB. The simulation results are consistent with
| + | |
| − | | + | |
| − | experimental measurements, and provide clues regarding improvements to the delivery
| + | |
| − | | + | |
| − | device.</B><br><br>
| + | |
| − | | + | |
| − | | + | |
| − | <h2>1.6 Model Variables</h2> <br><br>
| + | |
| − | | + | |
| − | ————表格还有表格底下的注释你自己弄哦————<br><br>
| + | |
| − | | + | |
| − | | + | |
| − | <h2>1.7 Model Parameters</h2> <br><br>
| + | |
| − | | + | |
| − | ————表格还有表格底下的注释你自己弄哦——<br><br>
| + | |
| − | | + | |
| − | <br><br>
| + | |
| − | References:<br>
| + | |
| − | 1. Takakura, Y., Nishikawa, M., Yamashita, F. and Hashida, M. (2001)
| + | |
| − | | + | |
| − | Development of gene drug delivery systems based on pharmacokinetic studies. European
| + | |
| − | | + | |
| − | journal of pharmaceutical sciences : official journal of the European Federation for
| + | |
| − | | + | |
| − | Pharmaceutical Sciences, 13, 71-76.<br>
| + | |
| − | 2. El Andaloussi, S., Lakhal, S., Mager, I. and Wood, M.J. (2013)
| + | |
| − | | + | |
| − | Exosomes for targeted siRNA delivery across biological barriers. Adv Drug Deliv Rev,
| + | |
| − | | + | |
| − | 65, 391-397.<br>
| + | |
| − | 3. Zhang, Y., Liu, D., Chen, X., Li, J., Li, L., Bian, Z., Sun, F.,
| + | |
| − | | + | |
| − | Lu, J., Yin, Y., Cai, X. et al. (2010) Secreted monocytic miR-150 enhances targeted
| + | |
| − | | + | |
| − | endothelial cell migration. Molecular cell, 39, 133-144.<br>
| + | |
| − | 4. Takahashi, Y., Nishikawa, M., Shinotsuka, H., Matsui, Y., Ohara,
| + | |
| − | | + | |
| − | S., Imai, T. and Takakura, Y. (2013) Visualization and in vivo tracking of the exosomes
| + | |
| − | | + | |
| − | of murine melanoma B16-BL6 cells in mice after intravenous injection. Journal of
| + | |
| − | | + | |
| − | Biotechnology, 165, 77-84.<br>
| + | |
| − | 5. Bartlett, D.W. and Davis, M.E. (2006) Insights into the kinetics of
| + | |
| − | | + | |
| − | siRNA-mediated gene silencing from live-cell and live-animal bioluminescent imaging.
| + | |
| − | | + | |
| − | Nucleic Acids Res, 34, 322-333.<br>
| + | |
| − | 6. Levitt, D.G. and Schoemaker, R.C. (2006) Human physiologically
| + | |
| − | | + | |
| − | based pharmacokinetic model for ACE inhibitors: ramipril and ramiprilat. BMC clinical
| + | |
| − | | + | |
| − | pharmacology, 6, 1.<br>
| + | |
| − | 7. Mulcahy, L.A., Pink, R.C. and Carter, D.R. (2014) Routes and
| + | |
| − | | + | |
| − | mechanisms of extracellular vesicle uptake. J Extracell Vesicles, 3.<br>
| + | |
| − | 8. Alvarez-Erviti, L., Seow, Y., Yin, H., Betts, C., Lakhal, S. and
| + | |
| − | | + | |
| − | Wood, M.J. (2011) Delivery of siRNA to the mouse brain by systemic injection of
| + | |
| − | | + | |
| − | targeted exosomes. Nature biotechnology, 29, 341-345.<br>
| + | |
| − | 9. Sible, J.C. and Tyson, J.J. (2007) Mathematical modeling as a tool
| + | |
| − | | + | |
| − | for investigating cell cycle control networks. Methods (San Diego, Calif.), 41, 238-
| + | |
| − | | + | |
| − | 247.<br>
| + | |
| − | 10. Cecchelli, R., Berezowski, V., Lundquist, S., Culot, M., Renftel,
| + | |
| − | | + | |
| − | M., Dehouck, M.P. and Fenart, L. (2007) Modelling of the blood-brain barrier in drug
| + | |
| | | | |
| − | discovery and development. Nat Rev Drug Discov, 6, 650-661.<br>
| + | We created mathematical models of three aspects of our project: a |
| − | 11. Lentz, T.L., Burrage, T.G., Smith, A.L., Crick, J. and Tignor,
| + | |
| | | | |
| − | G.H. (1982) Is the acetylcholine receptor a rabies virus receptor? Science, 215, 182-
| + | pharmacokinetic model, RNA inference model and signaling network model. |
| | | | |
| − | 184.<br>
| + | The source code of the modeling work is available <a href="https://static.igem.org/mediawiki/2015/4/4a/Model_Code.zip">here</a> or on our <a href="https://github.com/eldronzhou/IGEM-NJU-China-2015">Github Page</a> to help others |
| − | 12. Morishita, M., Takahashi, Y., Nishikawa, M., Sano, K., Kato, K.,
| + | |
| | | | |
| − | Yamashita, T., Imai, T., Saji, H. and Takakura, Y. (2015) Quantitative analysis of
| + | reproduce and improve our work. <br><br> |
| | | | |
| − | tissue distribution of the B16BL6-derived exosomes using a streptavidin-lactadherin
| |
| | | | |
| − | fusion protein and iodine-125-labeled biotin derivative after intravenous injection in
| + | The delivery module used experimental results to simulate the kinetics |
| | | | |
| − | mice. Journal of pharmaceutical sciences, 104, 705-713.<br>
| + | of tissue-distribution of exosomes. The RNAi module modeled the |
| − | 13. Kumar, P., Wu, H., McBride, J.L., Jung, K.E., Kim, M.H., Davidson,
| + | |
| | | | |
| − | B.L., Lee, S.K., Shankar, P. and Manjunath, N. (2007) Transvascular delivery of small
| + | kinetics of downregualtion of MOR protein in response to anti-MOR |
| | | | |
| − | interfering RNA to the central nervous system. Nature, 448, 39-43.<br>
| + | siRNA. The signaling module theoretically predicted the impacts of |
| − | 14. Lai, C.P., Mardini, O., Ericsson, M., Prabhakar, S., Maguire,
| + | |
| | | | |
| − | C.A., Chen, J.W., Tannous, B.A. and Breakefield, X.O. (2014) Dynamic biodistribution of
| + | downregulating MOR protein on the reward pathway and explained the |
| | | | |
| − | extracellular vesicles in vivo using a multimodal imaging reporter. ACS Nano, 8, 483-
| + | behavioral change of mice observed in our laratory work. We had a |
| | | | |
| − | 494.<br>
| + | better understanding of our device by integrating three modules. |
| − | 15. Banks, G.A., Roselli, R.J., Chen, R. and Giorgio, T.D. (2003) A
| + | <br><br> |
| | | | |
| − | model for the analysis of nonviral gene therapy. Gene Ther, 10, 1766-1775.<br>
| + | <img src="https://static.igem.org/mediawiki/2015/5/59/NJU-China-Model_Figure0.jpg" style="width:800px;height:400px"> |
| | + | <!--插入第一幅图--> <br><br> |
| | | | |
| | | | |
