PTEN differentially regulates endocytosis, migration, and proliferation in the enteric protozoan parasite Entamoeba histolytica.
PTEN differentially regulates endocytosis, migration, and proliferation in the enteric protozoan parasite Entamoeba histolytica.
复制标题
DOI：
10.1371/journal.ppat.1010147
复制
发表时间：
2022-05
期刊：
影响因子：
6.7
通讯作者：
中科院分区：
文献类型：
--
作者：
PTEN是一种高度保守的脂磷酸酶，在所有真核生物中广泛参与细胞骨架重组、内吞作用、信号转导和细胞迁移等生物学过程。虽然在模式生物和哺乳动物中已经很好地建立了通过PTEN调节磷脂酰肌醇(3，4，5)-三磷酸[PtdIns(3，4，5)P3]信号的机制，但在寄生原生原生动物组织溶解杆菌中，它仍然难以实现，它的发病机制严重依赖于依赖磷脂酰肌醇磷酸(S)的膜运输、迁移、吞噬和巨噬细胞增多。在本研究中，我们鉴定了6种可能的PTEN中在滋养体阶段转录水平最高的主要PTEN基因EhPTEN1，以了解PtdIns(3，4，5)P3信号在该寄生虫中的意义。GFP-EhPTEN1表达的阿米巴滋养体的实时成像显示，定位主要在胞浆中，在伪足和吞噬和吞噬细胞杯的延伸边缘有较高的浓度。此外，利用共聚焦图像细胞仪对吞噬和巨噬细胞增多进行了定量分析，结果表明，EhPTEN1基因的过度表达导致巨噬细胞和巨噬细胞吞噬功能的减少，而EhPTEN1基因的转录基因沉默导致了相反的表型。这些数据表明，EhPTEN1在这些生物过程中具有抑制作用。相反，EhPTEN1对溶组织棘球绦虫滋养体中的液相和受体介导的内吞作用起着积极的调节作用。此外，我们还发现EhPTEN1是该寄生虫最佳生长和迁移所必需的。最后证明了EhPTEN1对PtdIns(3，4，5)P3的磷酸酶活性，表明EhPTEN1的生物学作用可能与其催化功能有关。综上所述，这些结果表明，EhPTEN1通过PtdIns(3，4，5)P3信号对多种细胞活动进行不同的调节，这些细胞活动对生物体的增殖和发病至关重要。在分子水平上阐明PTEN和PtdIns(3，4，5)P3信号的生物学作用有助于我们理解这种寄生虫的发病机制。溶组织内阿米巴是一种肠道原虫寄生虫，可引起人类阿米巴痢疾和肝脓肿。人们已经很好地理解了阿米巴摄取和破坏人体细胞以及入侵组织的能力是如何导致血性腹泻等疾病症状的。这种活动的潜在机制，称为致病，包括运输(运输)和分泌细胞溶解蛋白，移动(变形体运动)，以及摄取和破坏人类细胞，严重依赖于信号转导系统，通过代谢(合成和分解)磷脂酰肌醇(含0-3磷酸的磷脂酰肌醇)，以及下游调节细胞骨架(细胞质中相互连接的蛋白细丝的动态网络，如肌动蛋白)。在这项研究中，我们鉴定了一种名为EhPTEN1的酶，它可以降解和失活PtdIns(3，4，5)P3。我们已经证明，EhPTEN1参与了可溶性和固体物质的迁移、内化(内吞、吞噬和吞噬)。EhPTEN1显然以一种复杂的方式调节细胞的迁移、内吞、转铁蛋白、吞噬和增殖。我们的发现有助于阐明PTEN在肠道寄生虫和其他致病寄生虫中的生理意义以及通过肌醇磷脂调节的细胞事件，并可能导致开发针对寄生虫病的新的控制措施。
PTEN is a lipid phosphatase that is highly conserved and involved in a broad range of biological processes including cytoskeletal reorganization, endocytosis, signal transduction, and cell migration in all eukaryotes. Although regulation of phosphatidylinositol (3,4,5)-trisphosphate [PtdIns(3,4,5)P3] signaling via PTEN has been well established in model organisms and mammals, it remains elusive in the parasitic protist E. histolytica, which heavily relies on PtdIns phosphate(s)-dependent membrane traffic, migration, and phago- and trogocytosis for its pathogenesis. In this study, we characterized the major PTEN from E. histolytica, EhPTEN1, which shows the highest expression at the transcript level in the trophozoite stage among 6 possible PTENs, to understand the significance of PtdIns(3,4,5)P3 signaling in this parasite. Live imaging of GFP-EhPTEN1 expressing amebic trophozoites showed localization mainly in the cytosol with a higher concentration at pseudopods and the extending edge of the phago- and trogocytic cups. Furthermore, quantitative analysis of phago- and trogocytosis using a confocal image cytometer showed that overexpression of EhPTEN1 caused reduction in trogo- and phagocytosis while transcriptional gene silencing of EhPTEN1 gene caused opposite phenotypes. These data suggest that EhPTEN1 has an inhibitory role in these biological processes. Conversely, EhPTEN1 acts as a positive regulator for fluid-phase and receptor-mediated endocytosis in E. histolytica trophozoites. Moreover, we showed that EhPTEN1 was required for optimal growth and migration of this parasite. Finally, the phosphatase activity of EhPTEN1 towards PtdIns(3,4,5)P3 was demonstrated, suggesting that the biological roles of EhPTEN1 are likely linked to its catalytic function. Taken together, these results indicate that EhPTEN1 differentially regulates multiple cellular activities essential for proliferation and pathogenesis of the organism, via PtdIns(3,4,5)P3 signaling. Elucidation of biological roles of PTEN and PtdIns(3,4,5)P3 signaling at the molecular levels promotes our understanding of the pathogenesis of this parasite. Entamoeba histolytica is an intestinal protozoan parasite that causes amoebic dysentery and liver abscesses in humans. It has been well understood how the amoeba’s ability to ingests and destroy human cells and invade tissues contributes to disease symptoms such as bloody diarrhea. The underlying mechanisms for such activities, called pathogenicity, include trafficking (transport) and secretion of cytolytic proteins, migration (ameboid movement), and ingestion and destruction of human cells, heavily rely on the signal transduction system via metabolism (synthesis and decomposition) of phosphoinositides (phosphatidylinositols containing 0–3 phosphates), and downstream regulation of cytoskeleton (dynamic network of interlinking protein filaments, such as actin, in the cytoplasm). In this study, we characterized one enzyme called EhPTEN1, which degrades and inactivate PtdIns(3,4,5)P3. We have shown that EhPTEN1 is involved in migration, internalization of soluble and solid materials (endocytosis, trogo-, and phagocytosis). EhPTEN1 apparently regulates cell migration, endocytosis, trogo-, phagocytosis, and proliferation in a complex fashion. Our findings help in the elucidation of the physiological significance of PTEN and cellular events regulated via phosphoinositides in this enteric parasite and other pathogenic parasites, and may potentially lead to the development of new control measures against parasitic diseases.
登录
查看更多内容
影响因子：
6.7
作者：
Bracha R;Nuchamowitz Y;Anbar M;Mirelman D
通讯作者：
Mirelman D
影响因子：
5.4
作者：
DIAMOND, LS;BARTGIS, IL;MATTERN, CFT
通讯作者：
MATTERN, CFT
影响因子：
3.3
作者：
Arhets, P;Olivo, JC;Guillén, N
通讯作者：
Guillén, N
影响因子：
3.1
作者：
Ghosh, SK;Samuelson, J
通讯作者：
Samuelson, J
影响因子：
6.7
作者：
Das K;Watanabe N;Nozaki T
通讯作者：
Nozaki T