Biology subjects

Ankley, L. M.

Publications and source records attributed to Ankley, L. M..

3 recordsLinked to original sources

bioRxiv2024

TGFβ primes alveolar-like macrophages to induce type I IFN following TLR2 activation

Alveolar macrophages (AMs) are key mediators of lung function and are potential targets for therapies during respiratory infections. TGF{beta} is an important regulator of AM differentiation and maintenance, but how TGF{beta} directly modulates the innate immune responses of AMs remains unclear. This shortcoming prevents effective targeting of AMs to improve lung function in health and disease. Here we leveraged an optimized ex vivo AM model system, fetal-liver derived alveolar-like macrophages (FLAMs), to dissect the role of TGF{beta} in AMs. Using transcriptional analysis, we first globally defined how TGF{beta} regulates gene expression of resting FLAMs. We found that TGF{beta} maintains the baseline metabolic state of AMs by driving lipid metabolism through oxidative phosphorylation and restricting inflammation. To better understand inflammatory regulation in FLAMs, we next directly tested how TGF{beta} alters the response to TLR2 agonists. While both TGF{beta} (+) and TGF{beta} (-) FLAMs robustly responded to TLR2 agonists, we found an unexpected activation of type I interferon (IFN) responses in FLAMs and primary AMs in a TGF{beta}-dependent manner. Surprisingly, mitochondrial antiviral signaling protein and the interferon regulator factors 3 and 7 were required for IFN production by TLR2 agonists and the IFN response was dependent on mitochondrial reactive oxygen species. Together, these data suggest that TGF{beta} modulates AM metabolic networks and innate immune signaling cascades to control inflammatory pathways in AMs.

immunology↗

bioRxiv2023

GSK3α/β restrains IFNγ-inducible costimulatory molecule expression in alveolar macrophages, limiting CD4+ T cell activation

Macrophages play a crucial role in eliminating respiratory pathogens. Both pulmonary resident alveolar macrophages (AMs) and recruited macrophages contribute to detecting, responding to, and resolving infections in the lungs. Despite their distinct functions, it remains unclear how these macrophage subsets regulate their responses to infection, including how activation by the cytokine IFN{gamma} is regulated. This shortcoming prevents the development of therapeutics that effectively target distinct lung macrophage populations without exacerbating inflammation. We aimed to better understand the transcriptional regulation of resting and IFN{gamma}-activated cells using a new ex vivo model of AMs from mice, fetal liver-derived alveolar-like macrophages (FLAMs), and immortalized bone marrow-derived macrophages (iBMDMs). Our findings reveal that IFN{gamma} robustly activates both macrophage types; however, the profile of activated IFN{gamma}-stimulated genes varies greatly between these cell types. Notably, FLAMs show limited expression of costimulatory markers essential for T cell activation upon stimulation with only IFN{gamma}. To understand cell type-specific differences, we examined how the inhibition of the regulatory kinases GSK3/{beta} alters the IFN{gamma} response. GSK3/{beta} controlled distinct IFN{gamma} responses, and in AM-like cells, we found GSK3/{beta} restrained the induction of type I IFN and TNF, thus preventing the robust expression of costimulatory molecules and limiting CD4+ T cell activation. Together, these data suggest that the capacity of AMs to respond to IFN{gamma} is restricted in a GSK3/{beta}-dependent manner and that IFN{gamma} responses differ across distinct macrophage populations. These findings lay the groundwork to identify new therapeutic targets that activate protective pulmonary responses without driving deleterious inflammation.

immunology↗

bioRxiv2020

A genome-wide screen in macrophages identifies new regulators of IFNγ-inducible MHCII that contribute to T cell activation

AbstractCytokine-mediated activation of host immunity is central to the control of pathogens. A key cytokine in protective immunity is interferon-gamma (IFN{gamma}), which is a potent activator of antimicrobial and immunomodulatory effectors within the host. A major role of IFN{gamma} is to induce major histocompatibility complex class II molecules (MHCII) on the surface of cells, which is required for CD4+ T cell activation. Despite its central role in host immunity, the complex and dynamic regulation of IFN{gamma}-induced MHCII is not well understood. Here, we integrated functional genomics and transcriptomics to comprehensively define the genetic control of IFN{gamma}-mediated MHCII surface expression in macrophages. Using a genome-wide CRISPR-Cas9 library we identified genes that control MHCII surface expression, many of which have yet to be associated with MHCII. Mechanistic studies uncovered two parallel pathways of IFN{gamma}-mediated MHCII control that require the multifunctional glycogen synthase kinase 3 beta (GSK3{beta}) or the mediator complex subunit MED16. Both pathways are necessary for IFN{gamma}-mediated induction of the MHCII transactivator CIITA, MHCII expression, and CD4+ T cell activation. Using transcriptomic analysis, we defined the regulons controlled by GSK3{beta} and MED16 in the presence and absence of IFN{gamma} and identified unique networks of the IFN{gamma}-mediated transcriptional landscape that are controlled by each gene. Our analysis suggests GSK3{beta} and MED16 control distinct aspects of the IFN{gamma}-response and are critical for macrophages to respond appropriately to IFN{gamma}. Our results define previously unappreciated regulation of MHCII expression that is required to control CD4+ T cell responses by macrophages. These discoveries will aid in our basic understanding of macrophage-mediated immunity and will shed light on mechanisms of failed adaptive responses pervasive in infectious disease, autoimmunity, and cancer.

immunology↗