Efficient Cholesterol Transport in Dendritic Cells Defines Optimal Exogenous Antigen Presentation and Toxoplasma gondii Proliferation.
Efficient Cholesterol Transport in Dendritic Cells Defines Optimal Exogenous Antigen Presentation and Toxoplasma gondii Proliferation.
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DOI：
10.3389/fcell.2022.837574
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发表时间：
2022
影响因子：
5.5
通讯作者：
Cebrian I
中科院分区：
文献类型：
--
作者：
Croce C;Garrido F;Dinamarca S;Santi-Rocca J;Marion S;Blanchard N;Mayorga LS;Cebrian I
树突状细胞是免疫系统中最强大的抗原呈递细胞。它们通过经典途径呈递与主要组织相容性复合体（MHC） II类分子相关的外源性抗原，刺激CD4+ T细胞，或与MHC- i通过交叉呈递途径激活CD8+ T淋巴细胞。dc是弓形虫感染时的主要细胞靶点之一。这种细胞内寄生虫结合必需的营养物质，如胆固醇，在一个高度特化的细胞器，寄生液泡（PV）内生长和增殖。在此过程中，弓形虫通过与蛋白质和脂质的多重相互作用来调节宿主的免疫反应。胆固醇是一种重要的细胞成分，在结构和功能水平上调节细胞生理。尽管不同的研究描述了胆固醇转运与外源性抗原呈递的相关性，但这一过程的分子机制尚未明确。在这里，我们重点研究了抑制剂U18666A，这是一种广泛用于阻止多泡体生物发生的药物，可阻断胆固醇运输并改变细胞膜的脂质组成。在用U18666A治疗骨髓源性DC （BMDC）时，我们证实了其向CD4+和CD8+ T细胞呈递外源性可溶性和颗粒性抗原的能力被严重破坏。引人注目的是，弓形虫相关抗原的呈现和寄生虫的增殖在处理细胞中受到阻碍。然而，U18666A处理既没有显著影响抗原摄取，也没有显著影响BMDC活力。相比之下，这种药物改变了MHC-I和MHC-II分子到质膜的运输。由于U18666A损害了MVBs的形成，我们分析了弓形虫感染的BMDCs中负责产生腔内囊泡的ESCRT机制。我们观察到不同的MVBs标记，包括ESCRT蛋白，被募集到PV。令人惊讶的是，ESCRT-III的主要成分CHMP4b被大量招募到PV，其表达水平在弓形虫感染BMDC后上调。最后，我们证明了用U18666A治疗BMDC会中断胆固醇的传递和CHMP4b向PV的募集，从而干扰寄生虫的有效复制。总之，我们的研究结果强调了dc中胆固醇运输和MVBs形成对最佳抗原呈递和弓形虫增殖的重要性。
Dendritic cells are the most powerful antigen-presenting cells of the immune system. They present exogenous antigens associated with Major Histocompatibility Complex (MHC) Class II molecules through the classical pathway to stimulate CD4+ T cells, or with MHC-I to activate CD8+ T lymphocytes through the cross-presentation pathway. DCs represent one of the main cellular targets during infection by Toxoplasma gondii. This intracellular parasite incorporates essential nutrients, such as cholesterol, to grow and proliferate inside a highly specialized organelle, the parasitophorous vacuole (PV). While doing so, T. gondii modulates the host immune response through multiple interactions with proteins and lipids. Cholesterol is an important cellular component that regulates cellular physiology at the structural and functional levels. Although different studies describe the relevance of cholesterol transport for exogenous antigen presentation, the molecular mechanism underlying this process is not defined. Here, we focus our study on the inhibitor U18666A, a drug widely used to arrest multivesicular bodies biogenesis that interrupts cholesterol trafficking and changes the lipid composition of intracellular membranes. Upon bone marrow-derived DC (BMDC) treatment with U18666A, we evidenced a drastic disruption in the ability to present exogenous soluble and particulate antigens to CD4+ and CD8+ T cells. Strikingly, the presentation of T. gondii-associated antigens and parasite proliferation were hampered in treated cells. However, neither antigen uptake nor BMDC viability was significantly affected by the U18666A treatment. By contrast, this drug altered the transport of MHC-I and MHC-II molecules to the plasma membrane. Since U18666A impairs the formation of MVBs, we analyzed in T. gondii infected BMDCs the ESCRT machinery responsible for the generation of intraluminal vesicles. We observed that different MVBs markers, including ESCRT proteins, were recruited to the PV. Surprisingly, the main ESCRT-III component CHMP4b was massively recruited to the PV, and its expression level was upregulated upon BMDC infection by T. gondii. Finally, we demonstrated that BMDC treatment with U18666A interrupted cholesterol delivery and CHMP4b recruitment to the PV, which interfered with an efficient parasite replication. Altogether, our results highlight the importance of cholesterol trafficking and MVBs formation in DCs for optimal antigen presentation and T. gondii proliferation.
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影响因子：
30.5
作者：
Basha G;Omilusik K;Chavez-Steenbock A;Reinicke AT;Lack N;Choi KB;Jefferies WA
通讯作者：
Jefferies WA
影响因子：
5.4
作者：
Buaillon, Celia;Guerrero, Nestor A.;Blanchard, Nicolas
通讯作者：
Blanchard, Nicolas
影响因子：
30.5
作者：
Anderson, HA;Hiltbold, EM;Roche, PA
通讯作者：
Roche, PA
影响因子：
6.4
作者：
Dou Z;McGovern OL;Di Cristina M;Carruthers VB
通讯作者：
Carruthers VB
影响因子：
7.7
作者：
Cebrian, Ignacio;Croce, Cristina;Mayorga, Luis S.
通讯作者：
Mayorga, Luis S.