Bovine fetal mesenchymal stem cells exert antiproliferative effect against mastitis causing pathogen Staphylococcus aureus

Abstract

Staphylococcus aureus is the most commonly isolated pathogen from clinical bovine mastitis samples and a difficult pathogen to combat. Mesenchymal stem cells (MSC) are multipotent progenitor cells equipped with a variety of factors that inhibit bacterial growth. The aim of the present study was to evaluate the in vitro antibacterial potential against S. aureus of conditioned medium (CM) from MSC derived from fetal bovine bone marrow (BM-MSC) and adipose tissue (AT-MSC). BM-MSC, AT-MSC and fetal fibroblasts (FB) cultures were activated by infection with S. aureus . Bacterial growth was evaluated in presence of CM, concentrated CM (CCM), activated CM (ACM) and concentrated ACM (CACM) from BM-MSC, AT-MSC and FB. Gene expression of β-defensin 4A (bBD-4A), NK-lysine 1 (NK1), cathelicidin 2 (CATHL2), hepcidin (HEP) and indoleamine 2,3 dioxygenase (IDO) and protein expression of bBD-4A were determined in activated and non-activated cells. The majority of BM-MSC and AT-MSC expressed CD73, Oct4 and Nanog, and were negative for CD34. Growth of S. aureus decreased when it was exposed to CM from BM-MSC, AT-MSC and FB. Moreover, growth of S. aureus in CCM, ACM and CACM was lower compared to controls of CM from BM-MSC and AT-MSC. Activated AT-MSC increased mRNA levels of bBD4A and NK1, and protein levels of bBD4A in CM. Thus, CM from fetal bovine BM-MSC and AT-MSC has the capacity to reduce in average ~30% of S. aureus relative growth under in vitro conditions. The in vitro antibacterial effect of fetal bovine MSC may be mediated by bBD4A and NK1 activity.

Safety and efficacy of a mesenchymal stem cell intramammary therapy in dairy cows with experimentally induced Staphylococcus aureus clinical mastitis

“…Bovine fetal AT-MSC isolation and culture. AT-MSCs were harvested from fetal AT present in the abdominal omentum from male bovine fetuses (n = 9; 7-8 months of gestation) collected at a local abattoir [9][10][11] . Approximately 10 g of AT were isolated under aseptic conditions and deposited in PBS supplemented with 100 IU/mL penicillin, 100 μg/mL streptomycin and 2.5 μg/mL amphotericin B (Hyclone, Thermo Fisher Scientific, UT, USA).…”

“…RNA extraction, cDNA synthesis and quantitative PCR. Purification of total RNA from PBLs was performed using a GeneJET purification kit (Thermo Scientific, Vilnus, Lithuania), following the manufacturer's instructions [9][10][11] . Total RNA was extracted using GeneJET RNA purification kit (Thermo Scientific) according to the manufacturer's instructions.…”

“…In addition, bovine fetal AT-MSCs are able to induce angiogenesis under in vitro conditions, which may be mediated by expression of vascular endothelial growth factor (VEGF) and angiopoietin 1 (ANGPT1) 10 . Moreover, conditioned media from bovine fetal AT-MSCs induce an anti-proliferative effect against mastitis-causing S. aureus, which may be mediated by antibacterial peptides (AP) defensin β1 (DEFβ1) and NK Lysin 11 . These studies suggest that bovine fetal AT-MSCs are able to produce several factors that may be useful to control a variety of infectious conditions including bovine mastitis.…”

Stem Cells in Veterinary Medicine—Current State and Treatment Options

“…Still, additional studies are needed to assess potential immunomodulatory and anti-inflammatory properties of endometrial MSC and their potential in the treatment of endometriosis (260). In addition to the reproductive system pathologies, MSC therapy is also investigated for the potential treatment of mastitis in farm animals, showing an antiproliferative effect against Staphylococcus aureus mediated mastitis in cows (267) and reparative and antifibrotic effect in goat chronic mastitis (268).…”

Mesenchymal Stromal Cells as Potential Antimicrobial for Veterinary Use—A Comprehensive Review

“…A number of preconditioning methods have been employed over the years including hypoxia, serum deprivation, and exposure to antagonistic substances to improve MSCs' ability to differentiate or modulate immune cells. Conditions promoting antimicrobial activity are being examined with exposure to cytokines, target bacteria, bacterial components, vitamins, and antibiotics improving both direct and indirect antimicrobial effects (Gupta et al, 2012;Guerra et al, 2017;Johnson et al, 2017;Cahuascanco et al, 2019;Yagi et al, 2020).…”