Endocytic pathway rapidly delivers internalized molecules to lysosomes: an analysis of vesicle trafficking, clustering and mass transfer.
Endocytic pathway rapidly delivers internalized molecules to lysosomes: an analysis of vesicle trafficking, clustering and mass transfer.
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DOI：
10.1016/j.jconrel.2012.05.022
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发表时间：
2012-08
期刊：
影响因子：
--
通讯作者：
Chinmay Pangarkar;A. Dinh;S. Mitragotri
中科院分区：
文献类型：
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作者：
Chinmay Pangarkar;A. Dinh;S. Mitragotri
溶酶体在细胞内药物传递中起关键作用。对于基于酶的治疗，它们代表了一个潜在的靶点，而对于核酸或许多蛋白质药物，它们代表了潜在的降解位点。无论哪种方式，了解物质进入细胞后进入溶酶体的机制和过程对药物递送领域具有重要意义。除疏水小分子外，大多数治疗物质通过内吞作用进入细胞。内吞的货物通过微管转运转运到溶酶体，并最终通过内吞囊泡的系结和聚集被各种溶酶体共享，随后交换其内容物。本文采用实验和数值相结合的方法，研究了模型细胞系3T3成纤维细胞内吞囊泡内的传质速率。为了了解质传递与微管运输和囊泡聚集的关系，我们通过不同的药物改变了这两种性质。同时，通过扩散-平流方程和Smoluchowski方程分别模拟了微管运输和囊泡聚集。我们的分析表明，传质速率与微管运输和囊泡的聚类特性最佳相关。此外，在细胞的固有状态下，传质率最高。对微管运输或囊泡聚集的任何扰动都会导致向溶酶体的质量传递减少。这些结果表明，在没有外部干预的情况下，内吞途径似乎可以最大限度地将分子递送到溶酶体。讨论了减少向溶酶体传递质量的策略，从而延长分子在核内体或后期核内体中的停留时间，从而潜在地增加它们在溶酶体中处置之前逃逸的可能性。
Lysosomes play a critical role in intracellular drug delivery. For enzyme-based therapies, they represent a potential target site whereas for nucleic acid or many protein drugs, they represent the potential degradation site. Either way, understanding the mechanisms and processes involved in routing of materials to lysosomes after cellular entry is of high interest to the field of drug delivery. Most therapeutic cargoes other than small hydrophobic molecules enter the cells through endocytosis. Endocytosed cargoes are routed to lysosomes via microtubule-based transport and are ultimately shared by various lysosomes via tethering and clustering of endocytic vesicles followed by exchange of their contents. Using a combined experimental and numerical approach, here we studied the rates of mass transfer into and among the endocytic vesicles in a model cell line, 3T3 fibroblasts. In order to understand the relationship of mass transfer with microtubular transport and vesicle clustering, we varied both properties through various pharmacological agents. At the same time, microtubular transport and vesicle clustering were modeled through diffusion–advection equations and the Smoluchowski equations, respectively. Our analysis revealed that the rate of mass transfer is optimally related to microtubular transport and clustering properties of vesicles. Further, the rate of mass transfer is highest in the innate state of the cell. Any perturbation to either microtubular transport or vesicle aggregation led to reduced mass transfer to lysosome. These results suggest that in the absence of an external intervention the endocytic pathway appears to maximize molecular delivery to lysosomes. Strategies are discussed to reduce mass transfer to lysosomes so as to extend the residence time of molecules in endosomes or late endosomes, thus potentially increasing the likelihood of their escape before disposition in the lysosomes.