Potential Diagnostic Value of the Peripheral Blood Mononuclear Cell Transcriptome From Cattle With Bovine Tuberculosis

Abstract

Bovine tuberculosis (bTB) is a chronic disease of cattle caused by Mycobacterium bovis. During early-stage infection, M. bovis-infected cattle shed mycobacteria through nasal secretions, which can be detected via nested-polymerase chain reaction (PCR) experiments. Little research has focused on immune responses in nested PCR-positive (bTB PCR-P) or nested PCR-negative (bTB PCR-N) M. bovis-infected cattle. Here, we investigated the transcriptomes of peripheral blood mononuclear cells (PBMCs), with or without stimulation by purified protein derivative of bovine tuberculin (PPD-B), among bTB PCR-P, bTB PCR-N, and healthy cattle using RNA-Seq. We also explored the potential value of PBMC transcripts as novel biomarkers for diagnosing bTB. Numerous differentially expressed genes were identified following pair-wise comparison of different groups, with or without PPD-B stimulation (adjusted p < 0.05). Compared with healthy cattle, bTB PCR-P, and bTB PCR-N cattle shared 5 significantly dysregulated biological pathways, including Cytokine-cytokine receptor interaction, NF-kappa B signaling pathway, Hematopoietic cell lineage, Osteoclast differentiation and HTLV-I infection. Notably, dysregulated biological pathways of bTB PCR-P and bTB PCR-N cattle were associated with cell death and phagocytosis, respectively. Lymphotoxin alpha and interleukin-8 could potentially differentiate M. bovis-infected and healthy cattle upon stimulation with PPD-B, with area-under-the-curve (AUC) values of 0.9991 and 0.9343, respectively. B cell lymphoma 2 and chitinase 3-like 1 might enable differentiation between bTB PCR-P and bTB PCR-N upon stimulation with PPD-B, with AUC values of 0.9100 and 0.8893, respectively. Thus, the PBMC transcriptome revealed the immune responses in M. bovis-infected cattle (bTB PCR-P and bTB PCR-N) and may provide a novel sight in bTB diagnosis.

In-depth systems biological evaluation of bovine alveolar macrophages suggests novel insights into molecular mechanisms underlying Mycobacterium bovis infection

“…As discussed in the blue module, apoptosis of macrophages infected with intracellular bacilli such as M. bovis and M. tuberculosis actively destroys infected host cells and their contents, including intracellular mycobacteria, thereby limiting mycobacterial growth and proliferation (Behar et al, 2011;Nalpas et al, 2015). In contrast, research has shown that one of the major mechanisms of escaping the host immune response and increasing mycobacterial survival is macrophage apoptosis subversion by M. bovis and M. tuberculosis (Keane et al, 2000;Behar et al, 2011;Abdalla et al, 2020;Fang et al, 2020). Interestingly, activation of the PI3K-Akt signaling pathway during mycobacterial infection directly modulates the apoptosis of host cells (Gong et al, 2020).…”

“…Additionally, in terms of the hub-central genes identified in the brown module, several hub-central genes such as SRC (Chandra et al, 2016), ITGB3 (Chen et al, 2021a), BCL2L1 (Sharma et al, 2016), CDKN1A (Silva et al, 2021), MDM2 (Shariq et al, 2021) (Fang et al, 2020). Interestingly, research has reported that M. tuberculosis infection leads to upregulation of the SRC hub-central gene, which directly inhibits phagosomelysosome fusion and plays an effective role in maintaining mycobacterial survival within macrophages (Lechartier et al, 2014).…”

High-resolution transcriptomics of bovine purified protein derivative-stimulated peripheral blood from cattle infected withMycobacterium bovisacross an experimental time course

“…In this regard, a previous study of unstimulated PBL from M. bovis -infected and non-infected control cattle showed enrichment and suppression of the related IPA ® Leukocyte Extravasation Signalling pathway [30]. In addition, enrichment of a very similar KEGG pathway ( Leukocyte Transendothelial Migration ) was also observed in a recent RNA-seq-based transcriptomics study of peripheral blood mononuclear cells (PBMC) from control healthy cattle versus animals that were classified PCR-positive for bTB disease using an M. bovis mpb70 gene nested PCR amplicon with nasal swabs [26].…”

Transcriptional Profiling of Human Peripheral Blood Mononuclear Cells Stimulated by Mycobacterium tuberculosis PPE57 Identifies Characteristic Genes Associated With Type I Interferon Signaling

“…A comprehensive analysis is thus essential in order to fully elucidate the complex responses of the host immune system to these mycobacterial antigens. As such, transcriptomic and bioinformatic analyses are of value as they offer a thorough understanding of the host defense mechanisms and immune evasion strategies associated with particular infections ( Zhao et al., 2017 ; Wang et al., 2019 ; Fang et al., 2020 ). Several studies have explored the immune effect of PPE57 exposure ( Zhang et al., 2007 ; Wang et al., 2008 ; Xu et al., 2015 ), but further work is needed to clarify host-pathogen interactions in this context.…”

“…RNA sequencing (RNA-seq) is a high-throughput technique to assess the full transcriptome of samples to identify gene expression in a manner more comprehensive than traditional microarray analyses ( Stark et al., 2019 ). Blood transcriptomic profiling is frequently conducted to evaluate host immune responses to particular stimulants or pathogens ( Wang et al., 2016 ; Fang et al., 2020 ). Herein, we employed an RNA-seq approach to identify genes that were differentially expressed in PBMCs upon stimulation with PPE57 to better understand global host-specific mechanisms related to the immune response in the context of TB infection.…”