Pro-Inflammatory Response of Bovine Polymorphonuclear Cells Induced by Mycoplasma mycoides subsp. mycoides.

Marta Di Federico,Tiziana Di Febo,Valeria Di Lollo,Giuseppe Marruchella,Flavio Sacchini,Mirella Luciani,Cesare Cammà,Massimo Ancora,Mauro Mattioli,Massimo Scacchia,Gianluca Orsini,Ivanka Krasteva

doi:10.3389/fvets.2020.00142

Abstract

Mycoplasma mycoides subsp. mycoides (Mmm) is the etiological agent of contagious bovine pleuropneumonia (CBPP), one of the major diseases affecting cattle in sub-Saharan Africa. Some evidences suggest that the immune system of the host (cattle) plays an important role in the pathogenic mechanism of CBPP, but the factors involved in the process remain largely unknown. The present study aimed to investigate the cell response of bovine polymorphonuclear neutrophils (PMNs) after Mmm in vitro exposure using one step RT-qPCR and Western blotting. Data obtained indicate that gene and protein expression levels of some pro-inflammatory factors already change upon 30 min of PMNs exposure to Mmm. Of note, mRNA expression level in Mmm exposed PMNs increased in a time-dependent manner and for all time points investigated; targets expression was also detected by Western blotting in Mmm exposed PMNs only. These data demonstrate that when bovine PMN cells are triggered by Mmm, they undergo molecular changes, upregulating mRNA and protein expression of specific pro-inflammatory factors. These results provide additional information on host-pathogen interaction during CBPP infection.

Highlights

Mycoplasma mycoides subsp. mycoides (Mmm) is the etiological agent of contagious bovine pleuropneumonia (CBPP), a severe respiratory disease of cattle notifiable to the World Organization for Animal Health (Office International des Epizooties [OIE]) [1]
IL-1β, IL8, and 5-LOX gene expression levels in Polymorphonuclear cells (PMNs) exposed to Mmm were significantly higher to control values (P < 0.05) in all time point tested
Acute-subacute CBPP pulmonary lesions from infected animals are characterized by a massive infiltration of inflammatory cells, with a relevant component represented by neutrophil granulocytes, together with the presence of high levels of some pro-inflammatory factors (TNFα, IL-1β, and IL-17A) [29]

Summary

Introduction

Mycoplasma mycoides subsp. mycoides (Mmm) is the etiological agent of contagious bovine pleuropneumonia (CBPP), a severe respiratory disease of cattle notifiable to the World Organization for Animal Health (Office International des Epizooties [OIE]) [1]. In adult cattle PMNs represent the second most abundant leukocyte population with a neutrophil-to-lymphocyte ratio of ∼1:2, which is lower compared to other domestic animals where PMNs represent up to 75% of the population of circulating leukocytes [12, 13] These cells are rapidly recruited to inflammatory and infection sites to provide early defense against invading microorganisms. PMNs are professional phagocytes and take part in pathogen clearance through several mechanisms like degranulation, phagocytosis, antibody derived cell cytotoxicity, and release of neutrophil extracellular traps (NETs) [15, 16] Beside their involvement in primary host defense against infections, PMNs contribute to regulate inflammatory and immune responses [17]. In CBPP, lungs showing acute-to-subacute stages of infection are characterized by an abundant cell inflammatory infiltrate containing PMNs and alveolar macrophages, suggesting the possible involvement of these cells in defensive and pathological mechanisms [19, 20]

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Results

Conclusion