Mastitis, the inflammation of the mammary gland, is an important disease affecting dairy animals worldwide. The disease is caused by mammary pathogenic bacteria and Escherichia coli are frequently implicated. Virulence factors of mammary pathogenic E. coli are only partially known and intramammary challenge with LPS elicits neutrophil recruitment in experimental bovine and murine mastitis models. We have previously shown that neutrophil recruitment in LPS-induced murine mastitis is strictly dependent on mammary alveolar macrophages. However, the relative role of alveolar macrophages and blood neutrophils in E. coli mastitis is not well defined. To this end, we selectively depleted mammary alveolar macrophages or blood neutrophils before intramammary challenge with E. coli strain P4 (ECP4). Mice depleted of alveolar macrophages prior to intramammary challenge recruited neutrophils normally and restricted bacterial growth and interstitial invasion. Importantly however, upon depletion of alveolar macrophages, ECP4 invaded the mammary alveolar epithelial cells and formed intracellular bacterial communities. In contrast, neutrophil depletion prior to intramammary infection with ECP4 was associated with unrestricted bacterial growth, tissue damage, severe sepsis and mortality. This study suggests that neutrophils but not alveolar macrophages provide essential antimicrobial defense against mammary pathogenic E. coli. Furthermore, we show here similar invasion after depletion of alveolar macrophages as in our previous studies showing that LPS/TLR4 signaling on alveolar macrophages abrogates ECP4 invasion of the mammary epithelium. Interestingly, similar ECP4 invasion and formation of intracellular communities were also observed following intramammary infection of either iNOS gene-deficient or IL-1 receptor type 1 gene-deficient mice.
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http://dx.doi.org/10.1051/vetres/2010025 | DOI Listing |
Phytomedicine
January 2025
Co-construction collaborative innovation center for Chinese medicine and respiratory diseases by Henan & education ministry of China, Henan University of Chinese Medicine, Zhengzhou, China; Henan Key Laboratory of Chinese Medicine for Respiratory Disease, Henan University of Chinese Medicine, Zhengzhou, China; Department of Respiratory Diseases, The First Affiliated Hospital of Henan University of Chinese Medicine, Zhengzhou, China. Electronic address:
Background: The unclear chemical composition and mechanisms of action pose challenges for new drug development and quality control of traditional Chinese medicine (TCM) formulas. To address this, the concept of effective-component compatibility (ECC) was proposed to represent drug combination with equivalent efficacy to TCM formulas, along with clear composition and dosage. However, previous strategies for screening ECC have often overlooked the synergistic effects of its components.
View Article and Find Full Text PDFMicrob Pathog
January 2025
National Key Laboratory of Agricultural Microbiology, College of Veterinary Medicine,Huazhong Agricultural University, Wuhan, China; Hubei Hongshan Laboratory, Wuhan, China; The Cooperative Innovation Center for Sustainable Pig Production, Huazhong Agricultural University, Wuhan, China. Electronic address:
The spread of Porcine contagious pleuropneumonia (PCP), a severe disease that occurs in pigs caused by Actinobacillus pleuropneumoniae (APP), remains a threat to the porcine farms and has been known to cause severe economic losses. Serum amyloid A (SAA) is an acute-phase protein rapidly expressed in response to infection and inflammation in vertebrates. This study aimed to investigate the function of SAA3 in bacterial infections.
View Article and Find Full Text PDFAm J Respir Cell Mol Biol
January 2025
The University of Texas Medical Branch at Galveston, Microbiology and Immuology, Galveston, Texas, United States.
Exposure to influenza A virus (IAV), respiratory syncytial virus (RSV), and human metapneumovirus (hMPV) is well-known to increase the risk of pneumonia in humans. Type I interferon (IFN-I) is a hallmark response to acute viral infections, and alveolar macrophages (AMs) constitute the first line of airway defense against opportunistic bacteria. Our study reveals that virus-induced IFN-I receptor (IFNAR1) signaling directly impairs AM-dependent antibacterial protection.
View Article and Find Full Text PDFIn Vitro Model
June 2024
In Vitro Toxicology Group, Faculty of Medicine, Health and Life Sciences, Swansea University Medical School, Swansea University, Sketty, Wales SA2 8PP UK.
Unlabelled: Owing to increased pressure from ethical groups and the public to avoid unnecessary animal testing, the need for new, responsive and biologically relevant in vitro models has surged. Models of the human alveolar epithelium are of particular interest since thorough investigations into air pollution and the effects of inhaled nanoparticles and e-cigarettes are needed. The lung is a crucial organ of interest due to potential exposures to endogenous material during occupational and ambient settings.
View Article and Find Full Text PDFFront Immunol
January 2025
Animal Disease Prevention and Control and Healthy Breeding Engineering Technology Research Centre, Mianyang Normal University, Mianyang, China.
Introduction: Porcine reproductive and respiratory syndrome virus (PRRSV) is a major pathogen that has caused severe economic losses in the swine industry. Screening key host immune-related genetic factors in the porcine alveolar macrophages (PAMs) is critical to improve the anti-virial ability in pigs.
Methods: In this study, an model was set to evaluate the anti-PRRSV effect of tylvalosin tartrates.
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