The RNA binding protein HNRNPA2B1 shapes the macrophage transcriptome to promote antimycobacterial immunity

The National Institute of Allergy and Infectious Diseases awarded Vanderbilt University Medical Center $262,388 on August 4, 2026, under the Allergy and Infectious Diseases Research program (CFDA 93.855) to investigate how the RNA binding protein HNRNPA2B1 regulates macrophage responses to Mycobacterium tuberculosis infection.

The research examines alternative splicing as a mechanism controlling the balance between MTB virulence and host antimicrobial defenses. The award funds work to define how HNRNPA2B1 impacts MTB pathogenesis using a conditional knockout mouse model, identify isoforms whose disruption renders macrophages permissive to MTB replication, and characterize the role of these splicing events in controlling cell-intrinsic immune responses. Preliminary data show that macrophages lacking A2B1 fail to constrain MTB replication over five-day infection, and RNA-seq analysis has identified 57 RNAs undergoing significant isoform shifts during MTB infection in A2B1-deficient macrophages.

Work is performed at Vanderbilt University Medical Center in Forest Hills, Tennessee, with a period of performance from August 4, 2026, through July 31, 2028. The award is classified as a Project Grant, a mechanism supporting discrete research efforts in infectious disease and related biomedical areas.

Abstract

MTB only causes disease in a fraction of the humans IT infects. Onset and progression of active TB disease result from upsetting the delicate balance between MTB virulence and host defenses. Alternative splicing (as), the process by which different mrnas can be generated from a single transcript, plays a major role in regulating gene expression and diversifying the proteome. Because IT dynamically tunes the functional output of protein expression, as is positioned to play a critical role in maintaining an equilibrated MTB- macrophage host-pathogen interface and keeping MTB pathogenesis at BAY. We recently became interested in a splicing factor called HNRNPA2B1 (A2B1), a ubiquitously-expressed RNA binding protein with well- established links to neurodegenerative disease and cancer. We and others have recently linked A2B1 to antibacterial immunity, demonstrating that mice lacking A2B1 in their myeloid compartment are susceptible to salmonella, e. Coli, and listeria infection. Despite these compelling phenotypes, the function of A2B1 in macrophages and its ability to control cell-intrinsic immune responses remain unexplored. To fill this GAP and gain new insights into how splicing controls the MTB-macrophage host-pathogen interface, we derived bmdms from wild-type and A2B1 CKO mice (lysmcre) and infected them with MTB. Remarkably, we observed that A2B1 KO bmdms fail to constrain MTB replication over a 5-day infection. Using RNA-SEQ and splice-aware computational pipelines, we have identified 57 rnas that undergo significant isoform shifts during MTB infection in A2B1 KO macrophages. We hypothesize that disrupting the balance of one or more of these isoforms renders A2B1 KO macrophages permissive to MTB. This proposal aims to define how A2B1 impacts MTB pathogenesis in the CKO mouse model, identify the culprit(s) of this replication phenotype in macrophages in vitro, and deliver antisense oligonucleotides (asos) to toggle splicing of pre-mrnas, boosting the generation of protein isoforms that restrict MTB replication. By promoting the expression of protective isoforms using asos we may be able to make MFS hyper-restrictive to intracellular pathogens like MTB. Thus, our work lays the foundation for the development of a new class of host-directed therapeutics to treat tuberculosis.