Co-PI: Brian Rudd

DESCRIPTION (provided by applicant): 

A defining feature of the adaptive immune system is the existence of specialized memory cells, which originate in response to a primary infection, and provide durable immunity during subsequent infections. Multiple types of memory T cells exist, with characteristic patterns of localization and functional specialization. Tissue-resident memory (TRM) T cells reside in each adult tissue and organ provide localized immunological memory and response to infection. Understanding the gene regulatory programs that specify TRM cells and enable their functional specialization is a major goal, and recent discoveries have revealed the identities of several transcription factors that play important roles in TRM T cells. Here, we propose to systematically examine whether microRNAs contribute to TRM cell gene regulatory programs, using human and mouse cells. MicroRNAs (miRNAs), a class of small regulatory RNAs, represent an essential additional layer of gene regulation, which act to repress target mRNAs post-transcriptionally. Notably, the majority of human genes are regulated by miRNAs, and the vast majority of gene regulatory pathways are believed to incorporate miRNAs. In the immune system, many critical events are regulated by miRNAs, however, no studies have investigated miRNAs in the context of TRM cells. In Aim I, we will use genomic approaches to identify miRNAs that are preferentially expressed in human and mouse TRM T cells, compared to central memory and effector memory T cells, and computational tools to define the miRNAs that are acting to regulate the transcriptome of TRM T cells. In Aim II, we will use mouse models to functionally validate roles for specific miRNAs in TRM T cells. Completion of these Aims will break new ground by generating comprehensive profiles of all miRNAs and their targeting signatures in diverse human and mouse TRM cell populations. This study is a pivotal first step towards understanding how specific miRNAs can be used to promote more durable immunity by increasing the formation and survival of TRM cells.