An innate host-associated antimicrobial agent impacts key inflammatory biomarker expression and production

Authors: DAWES, MAISIE - Western University Of Health Sciences; XIE, CHEN - Western University Of Health Sciences; Chitko-Mckown, Carol

Submitted to: World Wide Web
Publication Type: Abstract Only
Publication Acceptance Date: 7/24/2020
Publication Date: 8/14/2020
Citation: Dawes, M.E., Xie, C., Chitko-McKown, C.G. 2020. An innate host-associated antimicrobial agent impacts key inflammatory biomarker expression and production [abstract]. In: Poster session of SoCal's Virtual Immunology, Stemcell Technologies. Zoom meeting Aug. 14, 2020. World Wide Web. Poster session.

Interpretive Summary:

Technical Abstract: With pathogen eradication being the principal goal of immune system function, once activated, effector cells assume a state of protective inflammation. However, the host response sometimes manifests as a harmful constellation of clinical signs, known as the systemic inflammatory response syndrome (SIRS), a state of profound immune dysregulation. While the cause may be either infectious or non-infectious in nature, Gram-negative bacteria remain significant etiologies in multiple species including cattle, and are a primary cause of diarrhea, endotoxemia, septicemia and ultimately death in neonatal calves; this despite advances in anti-inflammatory therapy and critical care. Given the impact of the host response to disease in humans and food animals alike, we examined the effects of supplemental bovine lactoferrin (bLF) and its functional peptide lactoferricin B (LFcin B), on the dysregulated immune response to lipopolysaccharide (LPS). We hypothesized that these non-traditional antibiotic agents have therapeutic value as novel low-risk anti-inflammatory agents, a characteristic that appears to be attributable to their regulatory role on intracellular signaling in innate cells. Present in colostrum, saliva, and mucosal secretions, bLF is notably at its highest concentration in the secondary granules of neutrophils. In the host, the 25 AA peptide LFcin B is released following the activity of proteolytic enzymes in the stomach as well as at sites of infection. Viable peripheral monocytes and neutrophils were isolated from calves and stimulated in vitro with LPS/anisomycin (Aniso - the positive control), in the presence or absence of bLF/LFcin B/SB203580 (SB -the negative control). Using western immunoblot and immunoprecipitation techniques, we compared the effect of treatments on the expression of phosphorylated p38 and activation of the transcription factor ATF-2, respectively. Meanwhile, fold changes in nitrite production, and the expression of the genes of key cytokines - expressed as mean ± SD - were detected using qRT-PCR, Meso Scale Discovery Electrochemiluminescence, and the Griess assay, respectively. The latter assays were run in triplicate (qRT-PCR), and duplicate (MSD & Greiss assay). Results were analyzed using the Student’s t-test (GraphPad Prism 7 software). Differences between LPS/Aniso - induced stimulations and bLF/LFcin B/SB effects pre- and post- stimulation, were considered significant if the P value was <0.05. The observed immunomodulatory effects suggest bLF/LFcin B exert direct influence on upstream kinases of the p38 MAP kinase signaling pathway.