Hedgehog Induced ZFYVE21 Activates T Cell Intrinsic, NLRP3 Inflammasomes to Promote Chronic Inflammation

ZFYVE21 is a novel Rab5 effector involved in immune signaling whose functions in vivo are undefined. Using humanized mouse models and patient specimens, we describe a T cell-autonomous role for ZFYVE21 in promoting chronic inflammation. Following ischemia reperfusion injury (IRI), endothelial cells (ECs) produce Hedgehog (Hh) ligands. Hh ligands induce expression of ZFYVE21 in a “Ptchhi” cell population (CD3+CD4+CD45RO+Ptch1hiPD-1hi) that is highly responsive to Hh signaling and which display vigorous EC-mediated recruitment and effector responses in vivo. Mechanistically, following IFN-gamma-dependent priming, Hh-induced ZFYVE21 modulates T cell intrinsic, NLRP3 inflammasome activity in an Akt-dependent manner to allow IL-18-mediated potentiation of IFN-gamma responses. Hh-induced NLRP3 inflammasomes and T cell-specific ZFYVE21 augment vascular sequelae of chronic inflammation. Moreover, Ptchhi T cells highly expressing ZFYVE21 are expanded in IRI patients, and frequencies of these cells are modulated by Hh signaling. Hh-induced ZFYVE21 activates T cell intrinsic, NLRP3 inflammasomes to promote chronic inflammation. To do this, Tmem from 4 donors were stimulated with anti-CD3 in the presence of either anti-CD28 or SAG, and the P1-P4 populations emerging from these treatments were FACS-sorted for RNA sequencing.

ZFYVE21是一种新型Rab5效应蛋白，参与免疫信号转导，但其在体内的功能尚未明确。本研究借助人源化小鼠模型与患者标本，揭示了ZFYVE21在T细胞自主调控慢性炎症中的作用。缺血再灌注损伤（ischemia reperfusion injury, IRI）发生后，内皮细胞（endothelial cells, ECs）会分泌Hedgehog（Hh）配体。Hh配体可在“Ptchhi”细胞群（CD3+CD4+CD45RO+Ptch1hiPD-1hi）中诱导ZFYVE21的表达；该细胞群对Hh信号通路高度敏感，且在体内可被内皮细胞高效招募并激活效应应答。从机制层面来看，在干扰素-γ（IFN-γ）依赖性致敏后，Hh诱导的ZFYVE21会以Akt依赖的方式调控T细胞内源性NLRP3炎性小体（NLRP3 inflammasome）的活性，从而介导白细胞介素-18（IL-18）依赖的干扰素-γ应答增强效应。Hh诱导的NLRP3炎性小体与T细胞特异性ZFYVE21会加剧慢性炎症的血管并发症。此外，在IRI患者体内，高表达ZFYVE21的Ptchhi T细胞会出现扩增，且该类细胞的频率可受Hh信号通路调控。Hh诱导的ZFYVE21可激活T细胞内源性NLRP3炎性小体，进而促进慢性炎症的发生发展。为验证上述机制，研究人员对4名供者的Tmem细胞分别在抗CD28或SAG（Smoothened激动剂）存在的情况下用抗CD3进行刺激，随后将上述处理后产生的P1-P4细胞群通过荧光激活细胞分选（FACS）分离，用于RNA测序。