Defining Genome-Wide Expression and Phenotypic Contextual Cues in Macrophages Generated by Granulocyte/Macrophage Colony-Stimulating Factor, Macrophage Colony-Stimulating Factor, and Heat-Killed Mycobacteria

Abstract

Heat-killed (HK) Mycobacterium obuense (NCTC13365) is currently being evaluated in the clinic as an immunotherapeutic agent for cancer treatment. Yet, the molecular underpinnings underlying immunomodulatory properties of HK M. obuense are still largely undefined. To fill this void, we sought to perform immunophenotyping, chemokine/cytokine release analysis and genome-wide characterization of monocyte-derived macrophages (MDM) in which monocytes were originally isolated from healthy donors and differentiated by HK M. obuense (Mob-MDM) relative to macrophage colony-stimulating factor (M-MDM) and granulocyte/macrophage colony-stimulating factor (GM-MDM). Immunophenotyping and cytokine release analysis revealed downregulated surface expression of CD36, decreased spontaneous release of CCL2 and increased spontaneous secretion of CCL5, CXCL8/IL-8, IL-6, and TNF-α in Mob-MDM relative to M-MDM and GM-MDM. Analysis of cytostatic activity showed that Mob-MDM exhibited similar growth inhibitory effects on immortalized and malignant epithelial cells compared with GM-MDM but at an elevated rate relative to M-MDM. To understand global cues in Mob-MDM, we performed comparative RNA-sequencing (RNA-Seq) analysis of Mob-MDM relative to GM-MDM and M-MDM (n = 4 donors). Clustering analysis underscored expression profiles (n = 256) that were significantly modulated in Mob-MDM versus both M-MDM and GM-MDM including, among others, chemokines/cytokines and their receptors, enzymes and transcriptions factors. Topological functional analysis of these profiles identified pathways and gene sets linked to Mob-MDM phenotype including nitric oxide production, acute phase response signaling and microbe recognition pathways as well as signaling cues mediated by the proinflammatory cytokine, interferon-gamma, and the intracellular pattern recognition receptor, nucleotide-binding oligomerization domain-containing protein 2. Taken together, our study highlights molecular immune phenotypes and global signaling cues in Mob-MDM that may underlie immunomodulatory properties of HK M. obuense. Such properties could be of valuable use in immunotherapy approaches such as adoptive cell therapy against cancer.

Mucosal Immunoregulatory Properties of Tsukamurella inchonensis to Reverse Experimental Food Allergy

“…Heat-killed Actinomyces, such as Mycobacterium obuense or Mycobacterium vaccae, have shown to be safe and promising as immunotherapeutic agents in different clinical trials, which resulted in a significant improvement in the clinical outcome in patients with different cancers (14). Their action may be based on the adjuvant effect described on innate cells, thus enhancing immune response or immunomodulation (15)(16)(17). Our work highlights a previous study in which the heat-killed Gordonia bronchialis, an actinomycetal bacteria, prevented the activation of NF-kB on intestinal epithelial cells (8).…”

The multiplicity of infection does not affect interactions betweenCryptococcus neoformansand macrophages

“…However, caution is warranted when drawing conclusions by comparing different models, as human MDMs and murine J774 macrophages do not necessarily exhibit identical activation states (Lacey et al, 2012;Levitz and Farrell, 1990). It is also important to consider that the human MDMs may have shown bias in polarisation; human MDMs are typically classified as being M2-polarised (Bazzi et al, 2017), which is permissive to intracellular cryptococcal growth -though this potential polarisation still inhibited cryptococcal replication compared to J774 macrophages. It is also possible for the macrophages to shift their polarisation state, especially after introduction of infection or cytokines (Davis et al, 2013;Lacey et al, 2012), a phenomenon that may be interesting to dissect in the future.…”

Mycobacteria-Based Vaccines as Immunotherapy for Non-urological Cancers

“…Although HK- M. obuense showed great success in the treatment of pancreatic cancer patients, little was known about its cytotoxic and immunomodulatory activity. Recently, Bazzi et al published an extensive work on how IMM-101 modulates DC, macrophages, and granulocytes, in terms of surface markers and cytokine secretion profile [ 117 , 118 ].…”